1933 Institution of Mechanical Engineers: Visits to Works
Note: This is a sub-section of 1933 Institution of Mechanical Engineers
MESSRS. ALDER AND MACKAY.
The company was founded in 1850 for the manufacture of gas meters. The present works were built in 1891 and with subsequent extensions now have a floor space of approximately three acres and employ 450 hands. Extensive plant for punching, drawing, and shearing tinplate parts is installed, and there is also a brass foundry. The machine equipment includes hydraulic moulding machines, automatic turning and screwing lathes, capstan lathes, gear hobbing machines, power guillotines, drawing presses, milling machines and air pumps. About half the necessary driving power is provided by two 45 h.p. gas engines, the remainder being obtained by grouped electrical drives.
The factory is lighted in winter time with a modern high-pressure gas installation, and ample working space and ventilation are arranged for in all departments. Complete testing equipment is laid down for testing gas meters for tightness and accuracy of measurement, and alongside the factory is housed a Government testing station for the official stamping of all meters. The output is approximately one thousand meters per week.
The works, which are devoted to the construction of paper-making plant, cover an area of about three acres, and comprise modern steel buildings arranged generally in a series of long parallel bays, each equipped with electric overhead travelling crane and consisting of the usual machine and fitting shops. The pattern-making shop and pattern stores are in a separate building specially designed for the purpose. A small brass foundry and an up-to-date smiths' shop complete the buildings. The plant consists of the usual machine tools and equipment to be found in medium to heavy machinery-making works, but there are also a number of special machines and tools.
The notices of the various works, etc., visited in connexion with the Meeting were prepared for the information of members from particulars supplied by the respective authorities or proprietors.
An iron foundry acquired some years ago is situated at Westfield Road, about three miles from the St. Katherine's Works, and consists of steel-framed buildings designed for foundry work and equipped with modern melting furnaces and core-drying stoves, sand mixers, electric cranes, etc., to deal with castings up to approximately 20 tons in weight. The main offices at Sciennes consist of a newly constructed building in which the lighting, heating, and vacuum installation and general layout are noteworthy features.
The company have built 216 paper-making and board-making machines, excluding experimental machines, of which a considerable number have been constructed, and have been associated with many paper-making inventions of the first importance. Two of the most outstanding may be mentioned. Their patent wire frame has been described as the most revolutionary improvement since the introduction of the original Fourdrinier machine. It is arranged with a shaking breast roll with stationary side bars, the slice being arranged above the breast board, which is stationary, and any required "head" can be obtained to suit the speed, without pressure on the apron. The wire frame works in conjunction with a patent high-speed shake motion, and gives a closer formation of the sheet. The strength of the paper across the machine is thus considerably increased and in some cases has been made greater across than in the longitudinal direction. The firm have also successfully introduced a patent beater.
MESSRS. JAMES BERTRAM AND SON.
The firm was founded in 1845 and has throughout its history been mainly concerned with the production of machinery used in the manufacture of paper and pulp. The works comprise machine shops, erecting shops, pattern shop, smithy and brass foundry. Although the ground occupied by the works was formerly the site of an iron foundry, there is now no iron foundry, and iron castings are obtained from outside sources. The works are driven entirely by electricity, power being obtained from the Edinburgh Corporation.
MESSRS. BROWN BROTHERS AND COMPANY, ROSEBANK IRONWORKS.
For almost seventy years the firm has been engaged on the production of marine auxiliaries and hydraulic machinery. The founder of the firm, the late Mr. A. Betts Brown, M.I.Mech.E., was a prolific inventor, and as far back as 1888 he patented the steam tiller steering gear and the hydraulic steering telemotor. In recent years the firm has devoted attention to the development of electrohydraulic auxiliaries for ships, and particularly the electrohydraulic steering gear, which, although originally evolved to meet the requirements of motor vessels where steam is not available, has been adopted for ships of all classes. The firm are also the original patentees and principal manufacturers of hydraulic helm signals and indicators, and direct-acting reversing engines for controlling steam engines, turbines, and Diesel engines.
The works cover an area of five acres and employ normally about 600 men. They are equipped with up-to-date machine tools, and include a brass and an iron foundry.
MESSRS. BRUNTONS (MUSSELBURGH), MUSSELBURGH.
The works were first established about 1870, and came under the full control of the late Mr. W. N. Brunton in 1876. The firm commenced the manufacture of rope wire in 1888, and this has been their main product ever since. It was followed two years later by the manufacture of wire ropes for all purposes.
The works have been greatly extended since that date and now occupy a ground area of roughly 20 acres. The main works comprise a rod rolling mill, several wire drawing mills, with accessory heat-treating and pickling plant, bright-bar and shape-drawing factory, cold-rolled strip mills, and a large modern wire rope factory. There is also an extensive and fully equipped research laboratory.
The products of the works include rope wire, spring wire, music wire for mechanical purposes and for pianos, high-carbon drill steel wire and high-speed steel, and stainless steel wire. Among the special products are aircraft wires, the manufacture of which was commenced as long ago as 1906, armature binding wire, electrical resistance wire, aero-engine valve spring wire, and turbine blading. The firm are also the sole manufacturers of the "Haigh" alternating stress machine for the fatigue testing of metal.
MESSRS. T. AND A. CONSTABLE, UNIVERSITY PRESS.
This is the centenary year of the firm under the name of Constable, though it is the successor of an earlier firm. The work done is letterpress printing, mostly book work and mainly in black, though colour printing is also carried out. The present works, which were built in 1930, are laid out on one floor with roof lighting. There are departments for the setting up of type, both by hand and by Monotype machines. There is a foundry for the manufacture of electrotype and stereotype plates.
The printing department contains machines from the smallest size up to presses which print both sides of a sheet 45 by 68 inches in size. On such a machine 128 pages of the size of the usual novel can be printed at one operation. The binding department contains folding machines, thread and wire stitching machines, and paper-cutting guillotines. There is storage space for electrotype plates, for type, and for paper.
MESSRS. ALEXANDER COWAN AND SONS, VALLEYFIELD MILLS, PENICUIK.
The firm has been identified with the manufacture of paper at Penicuik, Midlothian, for more than a century and a half, during which the business has been carried on by successive generations of the family. It was founded by Charles Cowan in 1779, who purchased the mill and became a merchant in Leith, carrying on business in tea, wine, and paper. The output gradually rose until it reached a total of 8,000 tons in the year before the War, when about 600 workers were employed.
Since the War the mill has been reconstructed. In 1927 a large paper machine was installed and a new power plant started, a steam turbine and generator replacing the many steam engines previously used. The chief products are fine writing and printing papers, including a large variety of art papers. Envelopes are also manufactured.
CITY OF EDINBURGH ELECTRICITY SUPPLY, PORTOBELLO POWER STATION.
The site on which Portobello Power Station stands was purchased by the Corporation of Edinburgh in 1914. It is situated on the sea front, thus affording an unlimited supply of cooling water, and is conveniently located for the delivery of fuel from the Lothian coalfields. The construction of the station was, however, postponed during the War, and when in 1919 it could be commenced it was decided, in view of the developments in the supply of cheap electrical power which were then seen to be likely, to erect a station of much larger size than was originally intended. The first section was designed to accommodate 55,000 kW. of generating plant of which 37,500 kW. was immediately installed. This comprises six tri-drum water-tube boilers, each having a capacity of 80,000 lb. of steam per hour at a pressure of 300 lb. per sq. in. and a total temperature of 700 deg. F. The turbine plant comprises three 12,500 kW. turbo-alternator sets running at 1,500 r.p.m., and generating three-phase current at 6,600 volts, and 50 cycles per second. The turbines operate at 290 lb. per sq. in. pressure. In 1924 a further 12,500 kW. turbo-generator was installed, together with its complement of boilers, auxiliary plant and switchgear. In this case the turbine, which is of the two-cylinder impulse reaction type, is designed to run at 3,000 r.p.m. In the same year a 5,000 kW. turbo-generator set was reconditioned and transferred from the McDonald Road Station to Portobello. Thus the equipment of the first section of the station was completed.
The further extension of the station involved not merely the installation of an additional turbo-generator set with its boilers and switchgear but the civil engineering work associated with the preparation of foundations and the construction of the building, additional sea work, and coal sidings. Whilst the preliminary work was in progress the Electricity (Supply) Act, 1926, was passed and Portobello was declared one of the selected stations under the Act. It was decided to install two turbo-generating sets each having a maximum continuous rating of 31,250 kW., together with the complementary equipment. The floor space necessary represented approximately two-thirds of the remaining area of the site, but in view of probable future developments it was decided to construct the whole of the foundation raft necessary for the station in its final form in one operation. The additional building and constructional work, however, was confined to that required by the plant about to be installed. The work involved included the provision of an additional sea tunnel in view of the increased quantity of circulating water required, together with two new circulating water pumps each of 30,000 gal. per min. capacity. These pumps are of the vertical- spindle centrifugal type. Additional coal-handling plant has also been installed and with the present layout a duplicate feed is available to every coal bunker in the station. The steam-generating plant in each of the two new boiler houses consists of four units of the tri-drum type fitted with integral superheaters, tri-drum economizers and air heaters. Four of the new boilers are designed for a continuous output of 80,000 lb. of steam per hour, and four with an output of 90,000 lb. per hr. Mechanical stokers of the chain grate type are fitted. The turbines are of the three-cylinder type with double exhaust and two separate condensers per set.
The main switchgear in the station is of the metal-clad compound filled type with duplicate busbars. Complete phase separation has been maintained by assembling each phase busbar in a separate metal enclosing trunk and providing independent tanks on each phase of the main oil circuit breaker, the busbar selectors and cable isolating switches.
CITY OF EDINBURGH GAS DEPARTMENT.
The history of the undertaking dates back to the year 1818, when an Act was passed for lighting the city and suburbs of Edinburgh and places adjacent with gas. A company was formed for the purpose, under the name of the Edinburgh Gas Light Company. This company obtained another Act in 1829, and a further Act in 1840 to enable it "more effectually to light with Gas the town of Leith, the vicinity thereof and other places in the County of Edinburgh." In the same year, 1840, another company was incorporated under the name of the Edinburgh and Leith Gas Light Company, the Act being entitled "An Act for the better lighting with Gas the City of Edinburgh and town of Leith, and places adjacent." This company was known as the Leith Company to distinguish it from the original company which was referred to as the Edinburgh Company; but neither company paid any attention to the municipal boundaries of Edinburgh and Leith, each one carrying on its operations indiscriminately on both sides of these boundaries. A third company, the Edinburgh Oil Gas Company, with Sir Walter Scott, Bart., as Chairman, had been incorporated in 1824. This, however, was absorbed by the Edinburgh Company in 1829.
The existence of these rival undertakings led to friction and public discontent, and it was ultimately arranged in 1888 that the Corporations of Edinburgh and Leith should acquire the under- takings of both companies and set up a Joint Commission for the supply of gas in Edinburgh and Leith.
By 1898, the Commissioners found that though their works had been equipped with modern machinery they were unable to keep pace with the increase in business. They therefore obtained power by their Act of 1898 to construct new works at Granton. Operations on these works were commenced in the same year; the first section was formally opened in 1903, and the second section in 1906. The total cost up to that time was £842,000. The ground at Granton is over 106 acres in extent, and 50 acres are already occupied by the manufacturing buildings and plant.
No extensions of importance took place between the completion of the Granton Works in 1906 and the passing of the Edinburgh Extension Act, 1920. Owing, however, to the continued and increasing demand for gas for all purposes, the Town Council in 1924 approved of a scheme for the introduction of an improved type of carbonizing plant employing vertical retorts, together with the necessary coal and coke handling plant, surplus-heat boilers, and other accessories. In addition to and in anticipation of the extra yield from the new plant, larger and more efficient exhausters, condensers, washers, scrubbers and tar extracting plant were installed. The combined schemes involved an expenditure of roughly £250,000. The inauguration of the new vertical retort plant took place on 9th October 1926.
It also became necessary to make further provision for storage accommodation, and it was decided, after careful study of the problem, to erect a waterless gas holder, the first of its kind in Scotland, having a capacity of 5 million cu. ft., at a cost of about £65,000.
It was later considered advisable to install additional vertical retorts and coal and coke handling plant, at a cost of £150,000. This plant is of the battery type, and the retorts are heated by gas made in outside producers from the coke residue from the retorts. The coal and coke handling plant is both novel and extensive and consists of belt, gravity bucket, and push plate conveyers. Arrangements have also been made for blending the coal preparatory to carbonizing. Recently a fully automatic carburetted water-gas plant complete with waste-heat boilers has been erected, capable of producing 21 million cu. ft. per day. This is entirely self-acting, the various changes in the operations being controlled automatically by an intricate piece of mechanism. The plant was erected by Messrs. Humphreys and Glasgow at a cost of approximately £22,000.
The total output of gas last year amounted to 3,367 million cu. ft. of a calorific value of 500 B.Th.U. per cu. ft., and the number of consumers supplied was 120,668. The gas is pumped from the works, which are situated about 31 miles from the city, through a 48-inch main, by electrically driven boosters, each capable of dealing with 1 million cu. ft. of gas per hour. The electricity required for the boosters and for other motors on the works is generated either by gas engines or by steam engines supplied with steam from the waste-heat boilers. The gas is sent through over 540 miles of mains, and the area of supply covers approximately 50 square miles.
CITY OF EDINBURGH TRANSPORT DEPARTMENT.
The central repair works of the Transport Department, where all repair work is now concentrated, are situated at Shrubhill, Leith Walk. The buildings were erected about 1871 and were originally used as a depot for horse tramways. They are now used solely for the maintenance of the Department's fleet of 370 tramcars and 150 omnibuses and coaches. The vehicles are given a thorough overhaul every 12 or 15 months.
The engineering machine shop is equipped with several of the latest type of production machines, and the Department also operates a non-ferrous foundry for the production of overhead trolley wire fittings and aluminium, bronze, and gunmetal fittings. The body- building and repair shops are fully equipped for the production of complete car bodies, the rebuilding of omnibus bodies and repairs of all descriptions.
In 1932 the Department built a tramcar body of an entirely new design, with one-piece side pillars and longitudinal members of duralumin and aluminium, special extruded sections being obtained for this purpose. This car is of the straight-side type, with double cross seats in the lower saloon, giving an increased total seating capacity and a reduction of unladen weight of approximately 12 per cent per seated passenger. The car has been in service for twelve months with satisfactory results. Two tramcar bodies built entirely of steel, with the exception of the floors, have recently been supplied and placed in service. These are also of the straight-side type with increased seating capacity, and in the all-steel construction several interesting and novel methods in the use of steel members of light section have been used. They are the first double-deck tramcars of this type to be used in the country. The Transport Department has recently had a standard tramcar converted for regenerative control by a system which effects a reduction in overall power consumption of from 25 per cent to 30 per cent.
The garage for the fleet of omnibuses and coaches is situated a short distance from Shrubhill and has a floor area of approximately 10,000 sq. yards. A washing machine is installed, and a brake-testing machine is used for testing brakes on all four wheels simultaneously. An omnibus hoist facilitates inspection and repair. The bulk supply of petrol is situated outside the garage, and power-driven pumps enable filling to be rapidly carried out. Experiments are being made with tar oil as fuel in sleeve-valve and ordinary poppet-valve engines. The results so far have been very satisfactory.
CITY OF EDINBURGH WATER DEPARTMENT.
The waterworks at Alnwickhill were constructed about the year 1876 and consisted of a service reservoir, four filters, and a clear-water tank. The service reservoir has a capacity of 20 million gallons and was formed by means of an earthen embankment all round having a central puddle clay core. The slopes of the embankment both inner and outer are 2.5 to 1. The four filters have masonry walls with a central cement mortar core. The faces of the filter walls have a batter of 1 in 10, and the thickness of the walls is 3 ft. 6 in. at the top and 4 ft. 6 in. at the bottom. There is 3 feet depth of water and the filtering material originally consisted of 18 inches of fine sand, 6 inches of coarse sand, 6 inches of sea shells, 6 inches of fine gravel, and 3 ft. 3 in. of coarse gravel or broken stone. Below the filtering material fireclay pipes are laid to convey the filtered water to the outlet wells. Each of these filters is about 2,800 sq. yards in extent, but eight additional sand filters have since been constructed so that the total filtering area is now 35,000 sq. yards, the average area of each filter being about 3,000 sq. yards. Of the filters one at a time is always being cleaned. The original clear-water tank holds about 4.5 million gallons and is constructed with battered masonry walls like the filters and is covered with a roof of brick arching carried on brick pillars. A second tank built of brick has been added, and the capacity of the two tanks together is 10 million gallons.
At Fairmilehead there is a plant of Bell's mechanical filters consisting of twelve steel shells each 8 feet diameter. The plant is capable of dealing with 2 million gallons a day in a regular and continuous flow, for the water is delivered into a clear-water tank from which the supply to the town is drawn at an irregular rate. The stirring arms of the filters are driven by an electric motor. Sulphate of alumina is used to the extent of about one grain per gallon filtered, and after filtration chalk is added with the object of absorbing carbolic acid gas set free by the action of the alumina sulphate upon the natural carbonate contained in the water. In addition to the mechanical filters there are five open sand filters each 3,000 sq. yards in extent. The filter walls are built of unreinforced concrete vertical in the face with steps at intervals so that the thickness of the walls is 19 inches at the top and 2 ft. 9 in. at the bottom. The walls to a level below the sand are faced with English blue brick. The filtering material consists of 2 feet of sand brought from Arran or Loch Etive derived from disintegrated granite. Below the sand there are 3 inches of crushed granite, 3 inches of whinstone chips and 6 inches of broken whinstone. The floor of the filters is of concrete 9 inches thick put in in two layers 4.5 inches thick each with bitumen sheeting in between. The tank at Fairmilehead is also built of concrete, and the roof consists of arching carried on pillars.
In round figures 15 million gallons a day pass through the works at Alnwickhill and 7 million gallons a day through the works at Fairmilehead.
THE EDINBURGH AND LEITH FLINT GLASS WORKS.
The works were established over sixty years ago, and are now the only glass works producing fine table crystal in Scotland. All that was best in the old traditions of craftsmanship has been preserved, and many of the designs have probably been made in Edinburgh from the date of their original creation. All the glass is blown, and most of it is what is known as "full crystal," or lead potash glass. The glass is melted in crucibles, or pots, in modern furnaces of the recuperative type, and the articles are blown with or without the assistance of moulds, according to their character. The crucibles can be seen in process of manufacture in the works.
The works are mainly engaged in producing services and suites for table use. The craft of glass making is rooted in antiquity, and the firm is alive to the beauty of the old designs. In "period reproductions" the character of the originals has been recaptured by following in every essential the original process of manufacture, and by paying meticulous attention to such details as the correct elevation of the foot and the retention of the pontil mark.
THE FORTH BRIDGE.
The Forth Bridge, which crosses the estuary of the River Forth at Queensferry, forms a connexion in the East Coast Route of the London and North Eastern Railway between London and Aberdeen. Designed by Sir John Fowler and Sir Benjamin Baker, construction was started in December 1882, and the bridge was opened to traffic in March 1890, the cost being about £3,000,000 sterling. The total length of the bridge with its approaches is 1 mile 1,005 yards. The bridge itself is composed of three sections, the South Approach Viaduct, the Main Structure, and the North Approach Viaduct.
The South Approach Viaduct consists of ten spans of steel girders on masonry piers at 168-foot centres and four spans of stone arches giving a total length of 660 yards.
The Main Structure consists of three main cantilevers resting on masonry pier foundations, the centre one of which is situated on the Island of Inchgarvie; the main cantilevers support two suspended spans. The clear span between piers is 1,710 feet, the distance between the 12-foot diameter tubular columns being 145 feet, for the Queensferry and Fife Towers, and 260 feet for the Inchgarvie Tower. The height of the rails above sea level at high tide is about 157 ft. 8 in., and the extreme height to the top of the towers is 361 feet.
The main columns are splayed, being 120 feet apart at pier level and 33 feet at the top. This splay is maintained throughout the cantilevers and suspended spans. The weight of the 1,710-foot span is 11,571 tons, of the Inchgarvie Tower 7,036 tons, and of the Fife and Queensferry Towers 4,816 tons each. These weights, in addition to the live load, are carried by circular piers, 49 feet diameter at the top, increasing to 70 feet at the bottom in the case of the deepest pier, which has its foundation on the rock 89 feet below high water level.
The piers are constructed of rubble masonry, faced with granite, placed on a concrete foundation. Built into the masonry are forty-eight steel bolts 26 feet long, which fix the superstructure, allowance being made for expansion in the latter due to variation in temperature. The internal viaduct, which carries the track through the cantilevers and towers, has spans varying from 39 feet to 145 feet. The two centre suspended spans are identical and have a length of 346 ft. 6 in., the depth of the girders being 41 feet at the ends and 51 feet at the centre. The weight of the complete truss is 821 tons. These spans rest on rocking posts which transmit the weight to the cantilevers, at the same time permitting longitudinal movement in accordance with any variation in temperature.
The North Approach Viaduct is constructed in the same manner as the South Approach Viaduct, and consists of five spans of steel girders on stone piers at 168-foot centres, and three spans of stone arches giving a total length of 322 yards. The cantilevers were erected in such a manner that the structure was always approximately symmetrical about the centre of the tower, the suspended span being temporarily fixed to the end of the cantilever and erected as such, junction being made in the centre, and the temporary ties removed, leaving the span free on its bearings. The approach span girders were erected at a low level and jacked up as the piers were raised in height till the final level was reached.
The construction of the bridge involved the use of 54,160 tons of steel, 740,000 cu. ft. of granite, 48,400 cu. yards of ordinary stone, 64,300 cu. yards of concrete, 21,000 tons of cement, and 6,500,000 (or 4,200 tons) rivets. The total surface of steel extends to 145 acres and has to be painted every three years, requiring 17 tons of paint per annum. The number of men employed on the bridge is 48 in summer and 43 in winter.
The permanent way on the bridge consists of bridge section steel rails weighing 126 lb. to the yard, resting on teak bearers fixed on oak longitudinal timbers inside the steel rail troughs. The outside rail troughs act as the top booms of the main girders of the internal viaduct. Special expansion joints are fitted in the permanent way at the ends of the cantilevers to permit of longitudinal movement.
MESSRS. JOHN HERDMAN AND SONS, HAYMARKET FLOUR MILLS.
The original mill buildings were built very many years ago, and the surrounding portion of the city has since grown around them. The flour mill itself was rebuilt three years ago and is at present one of the most modern in the country in its equipment. The plant is driven by a 650 h.p. marine type engine, steam being supplied from boilers of recent design equipped with automatic stokers.
HERIOT-WATT COLLEGE, MECHANICAL ENGINEERING WORKSHOPS AND LABORATORIES.
Until 1908 the mechanical engineering workshops and laboratories were situated in the basement of the main building. The need for increased accommodation then led to the erection and equipment of a single-story building of 12,000 sq. ft. floor area on the site of a disused brewery at the rear of the college, at a cost of £18,000. This year, owing to the growing needs of the college as a whole, the Governors have embarked upon a large extension, the first section of which is in progress of construction. It has been necessary to demolish the smiths' shop and the strength of materials laboratory in order to make way for this new building, and to accommodate the equipment displaced in the remaining laboratories.
The new building will provide laboratories for strength of materials (including building materials), hydraulics, and mechanics, and a classroom. The existing mechanics laboratory will be devoted to motor-car engineering and to the study of fuels.
The workshops include a pattern shop (which is also used for carpentry and joinery), an engineering workshop, and a temporary smiths' shop. The equipment of the engineering workshop is being modernized; a universal milling machine, and a tool room lathe suitable for investigation of the use of high-speed tool steels, have recently been added. This workshop is used for instructional work, and for maintenance and the manufacture of apparatus.
In addition to the usual apparatus for the study of fuels, the analysis of gases, the quality of steam and similar determinations, the equipment includes a Stirling and a locomotive boiler, and an independently fired superheater, a de Laval turbine, and three reciprocating steam engines with condensers and measuring tanks which are so arranged that drainage of condensed steam from the cylinders to the tanks is by gravity. The larger of the two engines is fitted with jackets, and electrical resistance thermometers are provided.
In the internal-combustion section of the laboratory the main equipment consists of a compression-ignition engine of the Blackstone type, a National gas engine and a Petter two-stroke engine, a motor car chassis, and three petrol engines, all of these being arranged for a variety of tests. There are also an electrically driven air compressor of the two-stage type with separate water jackets to the cylinder barrels and heads, and a CO2-type refrigerating plant specially designed for experimental investigation.
The equipment relating to the testing of materials, temporarily accommodated in the other laboratories and in a small room at the bottom of the main staircase, includes a 100,000 lb. Greenwood and Batley universal testing machine, a 5-ton Avery universal machine, a torsion machine, a fatigue tester, an Izod machine, and two cement testing machines, all provided with the necessary extensometers and other measuring apparatus. There is also a small laboratory devoted to the study of the heat treatment and the microscopic examination of metals.
Students of the college prepare for National Diplomas and National Certificates in Mechanical Engineering and laboratory practice forms an important part of the instruction.
THE LEITH DOCK COMMISSION.
The recorded history of Leith Docks dates from 1329, when King Robert the Bruce granted a Charter of the "Harbour and Mills of Leith" to the City of Edinburgh. Until the beginning of the last century the accommodation for shipping at Leith consisted of what is now known as the Inner Harbour, which is formed in the bed of the stream known as the Water of Leith. On the banks of this stream quay walls had been built extending for nearly half a mile, but as no protecting piers were provided at the entrance, great difficulty was experienced by navigators in reaching the harbour. This was the position in 1799 when the Town Council of Edinburgh wisely consulted John Rennie, who designed and constructed for them the first two docks at Leith. These are known as the East and West Old Docks and are now only used by small vessels. About the year 1835, following a Government inquiry, the present Commission was formed to administer the Harbour and Docks. In 1847 the Victoria Dock was built and the piers extended to the plans of Mr. James Rendel, the dock being opened for traffic in 1853. The Victoria Dock is 750 by 300 feet. The entrance is 60 feet wide, and the sill is 6 feet lower than the Old Dock sill.
The next extension was the Albert Dock (opened in 1868) to the designs of Sir Alex. Rendel, and this and all further works were constructed on the east side of the Water of Leith on what was then known as the East Sands. The Albert Dock is 1,100 feet long and 450 feet wide, with a lock 350 feet long, 60 feet wide, and a sill 26 feet deep or 2 feet lower than the Victoria Dock. The Edinburgh Dock, which is an extension of the Albert Dock, was opened in 1881 and is 1,500 feet long and 650 feet wide. The Imperial Dock, the last dock constructed at Leith, was opened for traffic in 1902. It is 1,900 feet long, 550 feet wide for a length of 1,100 feet, and 280 feet wide for the remaining length of 880 feet. This dock is entered by a lock 350 feet long between sills 70 feet wide and 38 feet deep from coping to sill, giving a depth of water at high spring tides of about 30 feet.
New Hydraulic Power Station, Imperial Dock. — The Commissioners recently installed a new hydraulic power station at the Imperial Dock. The station is electrically driven and comprises five pumping units working against an accumulator pressure of 800 lb. per sq. in., and is capable of giving a total output of 2,800 gal. per min. Three of the pumping units are of the multi-stage centrifugal type, two having a capacity of 800 gal. per min. and one of 600 gal. per min. The remaining two units are of the reciprocating type, each with a capacity of 300 gal. per min. The electric motors installed in the power house have a total capacity of 2,067 h.p.
The station is built with a deep basement so that all piping and electric cables are placed below the power house floor and are readily accessible for inspection and repairs. Sea water pumped from the Imperial Dock is used as the source of supply, and three circulating pumps having a total capacity of 2,000 gal. per min. are provided in the station and pump the make-up water from the dock into overhead feed-water tanks having a total capacity of 12,000 gallons. The general layout of the plant is so arranged that with the exception of the electric motors, the whole of the electrical switchgear, contactors, control board, and meters have been kept separate from the pumping units and arranged on a raised part of the floor at one end of the power house.
The pressure pipes are so arranged as to supply the dock system through each end of the power house and the water is returned to the feed tanks. The pressure main at each end of the power house is fitted with a Venturi meter and the recording instruments are placed in the electrical section of the power house alongside the main control panel. The starting and stopping of the main pumps is automatically controlled by the rising and falling of a hydraulic accumulator. In order that each pump in its turn may get its fair share of work, a selector board is provided in the electrical section of the power house, by means of which the pumps can be started and stopped in four different sequences.
New Coal Hoists, Imperial Dock. — The two new hydraulic coal hoists at the Imperial Dock are of the latest design. They are of the movable type and are constructed to lift and tip a wagon weighing 30 tons. The truck traversers serving the two hoists form, perhaps, the most interesting item in the installation. They are fitted with two tipping rams, one for the full truck and one for the empty truck, and the power operating the wheels for moving the traversers to and fro on their rails is provided by variable speed gear (oil transmission), the prime mover being a constant running slip-ring motor mounted on the traverser floor. The virtue of the oil transmission system lies in the perfect control afforded, combined with considerable economy in electric power used. Both hoists are fitted with a 12-ton crane and anti-breakage box which is operated from the driver's cabin. One of the hoists is fitted with a "Norfolk Spade" for clearing "duff" or small coal from the wagons, a difficult operation on some occasions, especially during frosty weather.
Grain Discharging Plant and Storage Silos at Edinburgh Dock. — The grain ships arriving at Leith are discharged by means of two pneumatic discharging plants erected on the north quay of the Edinburgh Dock. These are of the travelling type and can, therefore, be placed at any point to suit the hatches of the ships. Each plant is capable of discharging 150 tons of wheat per hour, by means of two pipes, the lower ends of which are lowered into the holds of the ships, the upper ends being connected to a large steel container from which air is exhausted by means of a rotary air pump driven by an electric motor.
The grain is discharged from the steel container by means of a mechanically operated air lock and falls into an automatic weighing machine, after which it is lifted by a bucket elevator and discharged through a pipe on to one or two belt conveyers placed in a gantry over the transit shed at the back of the quay. This gantry extends to the grain warehouse at the head of the dock and the grain is there thrown off the belt through a chute and on to the grain-handling plant inside the warehouse.
The grain warehouse is built entirely of reinforced concrete and is a rectangular shaped building about 160 feet long by 114 feet wide. It is in two sections; one section, consisting of 55 silos, is for the storage of grain, and the other section, consisting of 32 smaller silos with the working floors and machinery, is used for the delivery of the grain. The storage capacity of the silos is 16,000 tons. Each storage bin is provided with an electrically controlled temperature recorder, which records the temperature of the grain in each bin at points every 10 feet down the bin. The roads and railways at the warehouse are so arranged that grain can be loaded in bulk or in sacks, either into railway wagons or motor lorries as required by the merchants.
An electric substation is provided adjacent to the warehouse. Energy is supplied by Edinburgh Corporation in the form of alternating current at 6,600 volts, and this is converted into direct current at 460 volts, by means of two 750 kW. motor converters. The interesting feature of the substation is that it is arranged to be controlled from the switchboard of the Commissioners' main station at the Albert Dock, which is nearly one mile away. This is done by means of a series of relays which are placed beside each of the motor converters in the substation and are connected by a pilot cable to the control panel in the main station.
The Commissioners are at present constructing a new grain warehouse at the Imperial Dock which will be capable of storing 20,000 tons of grain. This warehouse will be equipped with all the latest grain-handling appliances; and new grain-discharging plant of the pneumatic type is also being constructed on one of the quays of the Imperial Dock, where a pump house and electric substation will also be provided.
THE LOTHIAN COAL COMPANY, LADY VICTORIA PIT, NEWTONGRANGE.
This is the most extensive working on the coalfield operated by the company. Sinking operations were commenced in 1890, and the shaft is 1,650 feet deep. The winding engine, built by Messrs. Grant, Ritchie and Company of Kilmarnock, has two cylinders 42 inches diameter by 7 feet stroke. The steel winding drum is cylindrical, and is 20 feet diameter by 10 ft. 6 in. wide. The double-breast brakes are operated by a 12-inch steam cylinder placed directly in front of the drum. The winding ropes are recapped at intervals of six months. An overwinding arrangement worked by bevel gear from the crankshaft automatically shuts off steam from the engine at a point 30 fathoms from the surface, and applies the steam brake. The water pumped daily reaches a total of 5,000 tons — two and a half times the output of coal. The lower feeders are dealt with by electrically driven pumps situated at a depth of about 1,650 feet, and there are still lower feeders at about 2,750 feet.
Two 1,000 kW. mixed-pressure Curtis turbines driving three-phase B.T.H. alternators at a speed of 3,000 r.p.m. supply current at 3,300 volts. During the day the winding and haulage engines exhaust into an accumulator which supplies the turbine with steam at a pressure of 1 to 2 lb. per sq. in. above atmospheric pressure. When necessary live steam is automatically admitted from the boilers. The condensing plant was supplied by Messrs. Cooper and Greig of Dundee and gives 29 inches of vacuum at full load and 30 inches barometric pressure. The temperature of the cooling water is lowered in cooling towers.
The hauling engine was made by Messrs. Barclay and Company to sink the Lady Victoria Pit and afterwards was converted into a haulage engine. There are two cylinders 25 inches by 5 feet. The endless rope or band rope makes 4.5 turns round the 12-foot Clifton wheel and then passes down the pit to another 12-foot Clifton wheel. The latter is mounted on a shaft carrying three other Clifton wheels 8 feet in diameter, each of which drives an endless haulage rope about 8,000 yards in length. There are six boilers 30 feet by 8 feet, fitted with superheaters, and supplying steam at 100 lb. per sq. in. pressure.
The loaded hutches, as they are drawn from the cage, run by gravity to the weighing machine, and then pass to the various tipplers. The tipplers are belt-driven and make a complete revolution, depositing the coal in a heap on a slightly inclined distributing "jigger-plate." The coal is slowly pushed forward to a perforated jigging-screen lying at a steeper gradient, through which the dross falls into a scraper-conveyer travelling at right-angles to the jigger. The larger coal passes over the end of the jigging-screen to an endless belt of steel plates about 35 feet long and travelling about 60 ft. per min. Any foreign material which may be among the coal is picked out by men and boys stationed alongside the belt.
The dross from the various screens is carried by the scraper conveyer already mentioned to a dross "pit," sunk about 21 feet below surface level and alongside the washer. The dross is elevated out of the pit to a height of about 60 feet and deposited on a distributing plate, from which it passes to a series of inclined jigging- screens, with perforations, varying from 0.25 inch diameter at the top to 2.5 inches at the bottom.
The principle of this type of washer is to separate the coal into the various sizes required, and then wash each size separately. The coal is divided into five sizes, the first three of which are washed in bosh or plunger tanks and the remaining two over felspar. The quantity of water required to wash the coal is about 1,000 gal. per min. The fine coal washed away is used for firing the boilers at the colliery.
Electric coal-cutting machines and motor-driven conveyers are in operation in the workings. Instead of the usual wooden props, steel tubes are used for securing the roof at the coal face. These are recovered and the ends are cut off old props by an electrically driven disk cutter. The pit is ventilated in conjunction with the neighbouring Lingerwood Mine by a "Sirocco" fan 10 ft. 6 in. diameter. The fan is rope driven. A steam-driven Guibal fan 30 feet in diameter is held in reserve.
The "blaes," of which large quantities are removed in the workings, is brought to the surface and made into bricks. For this a complete brick-making plant is installed, and about 15,000 bricks per day are regularly manufactured.
MESSRS. MACKENZIE AND MONCUR, EDINBURGH FOUNDRY.
This iron foundry was opened in 1890 and covers an area of about 4 acres. It consists of moulding shops for greensand, drysand, and loam moulds, together with pattern and fitting shops and a small brass foundry. The shops are well equipped with electric travelling and hydraulic swing cranes. Electric current is taken from the Edinburgh Corporation, the alternating-current supply being converted to direct current for use in the foundry. Castings from a few pounds to 20 tons in weight are made mostly for mechanical and electrical engineers, and the present plant is capable of producing 100 tons per week.
Cast iron manhole covers, gully traps, and similar castings for roads are a speciality. All kinds of castings for structural work, including iron fire escape stairs, are made, and lamp pillars are supplied for many towns at home and abroad.
MESSRS. MORRISON AND GIBB.
The firm are engaged in the manufacture of books and catalogues, and in colour printing, bookbinding, etc. During the last five years a considerable amount of equipment of the most recent type has been installed for printing and bookbinding. There is a studio in which eight artists are employed on creative work.
THE NORTH BRITISH RUBBER COMPANY, CASTLE MILLS.
The company was established in Castle Mills in 1857, rubber footwear being originally the principal product. Plant was soon afterwards installed for making machinery belting, hose, and mechanical goods, and the factory has gradually developed until to-day it covers an area of over 20 acres. Footwear is still the chief item of production, but the company also manufacture practically everything else which is made of rubber.
Electric power is obtained from Edinburgh Corporation and is transformed and converted on the premises for use in the works and for lighting. Process steam is supplied by five Inglis boilers and two Lancashire boilers, fitted with "Underfeed" stokers, generating steam at 90 lb. per sq. in. pressure, together with one Cochrane and one gas-fired boiler, with a working pressure of 150 lb. per sq. in., the total steaming capacity being 100,000 lb. per hour. A water-softening plant, Howden-Ljungstrom preheaters, and an oil-fired installation form part of the boiler house plant. Hydraulic power is supplied throughout the works by electrically driven pumps and accumulators at working pressures of 1,750 and 1,250 lb. per sq. in. Compressed air at working pressures of 150 and 100 lb. per sq. in. is supplied by motor-driven Reavell compressors with a capacity of 1,600 cu. ft. of free air per minute. The machine and fitting shops deal with the general engineering requirements and manufacture moulds for general mechanical rubber goods and tyres.
MESSRS. BRUCE PEEBLES AND COMPANY.
The original company was founded in 1866 by the late Mr. David Bruce Peebles, the works being established for the manufacture of gas meters and gas appliances at Fountainbridge, Edinburgh. In 1876 the works were removed to Tay Works, Leith, at which the manufacture of electrical machinery was commenced in 1897. The present company was formed in 1902. The following year the firm acquired the site at East Pilton on the north side of Edinburgh, on which the present works and offices stand.
There can be few works which occupy so attractive or so healthy a site. On the north is a view of the Firth of Forth and the Highlands beyond, and on clear days the peaks of Ben Ledi and Ben Lomond are plainly visible; to the south a fine view of the city of Edinburgh and the Pentland Hills can be seen.
Extensions to the works were made in 1918, 1925, and 1930. The works and offices now cover an area of 15 acres and are in direct communication with the docks at Leith and Glasgow.
The company now manufacture all sizes and types of rotating electrical machinery, transformers, and rectifiers both of the steel-cylinder and glass-bulb types. These three different types of electrical plant are manufactured in three separate factories.
The electrical machinery shop includes the heavy engineering shop, tool room, pattern shop, smithy, and brass foundry. The heavy engineering shop, which deals with all types of rotating machinery, is 410 feet by 50 feet, and is equipped with the necessary overhead travelling cranes and jib cranes. This shop is capable of the complete manufacture and testing of large alternators with outputs up to 10,000 kVA., the largest motor converting and rotary converting plants, and generators and motors of all types and sizes. The firm were the original patentees of the "Peebles-la Cour" motor converter, and were also the first to supply converters operating at 1,500 volts d.c.
Adjacent to the heavy engineering shop a section has been allocated for the manufacture of mercury arc rectifiers. The firm possess an exclusive licence from Messrs. Brown Boveri for the manufacture of the steel cylinder rectifier. Many of these rectifiers have been supplied for traction service and for industrial power systems, including eighteen complete substation equipments for the Brighton electrification of the Southern Railway. This section also deals with the manufacture and assembly of glass bulb rectifier equipments.
The transformer shop is one of the most modern in the country.
It comprises four bays: the main bay 325 feet by 60 feet; two bays 225 feet by 30 feet; and one bay 150 feet by 30 feet. Since it commenced operation over 1,000,000 kVA. of transformers have been manufactured, the largest units having a capacity of 30,000 kVA. at 124,000 volts. Apart from the usual equipment necessary for the manufacture of transformers, the plant for the special treatment of core laminations, the welding shop, the vacuum and impregnating plant, and the testing plant, which includes a 500,000-volt testing transformer, are of interest.
Electric current is supplied from the Edinburgh Corporation at 6,200-7,000 volts, 50 cycles per second, three-phase, and is converted into direct current by a 500 kW. motor converter and a 500 kW. rotary converter, any other alternating current voltages for testing purposes being obtained by means of step-down transformers. There is also a motor generator to provide power for an electric shunting locomotive.
POST OFFICE AUTOMATIC TELEPHONE EXCHANGE, EDINBURGH CENTRAL.
The Edinburgh automatic telephone exchange system serves the whole of the area, with the exception of Leith, within a radius of five miles from the Central Exchange, which is situated in close proximity to the west end of Princes Street. Ten other exchanges housed in specially erected buildings in the suburbs are served from the Central Exchange. The total number of subscribers in the Edinburgh area is 17,958, and the number of trunk and junction circuits serving the eleven exchanges is 2,650. Approximately 16,500,000 local calls and 1,500,000 trunk calls were originated in the Edinburgh automatic area during the year 1932.
The ultimate direct exchange line capacity of the Edinburgh Central Exchange building is 15,000 subscribers' lines. At the present time, the exchange has equipment for 11,000 subscribers' lines. The whole of the equipment for the eleven automatic exchanges in the Edinburgh area was manufactured by Messrs. Siemens Brothers and Company of Woolwich. The automatic switching apparatus is of the step-by-step type and operates on Strowger principles. The switching apparatus comprises 10,460 first preselectors, 1,340 second preselectors, 3,609 second, third, and incoming selectors, 801 ordinary final selectors, and 537 private branch exchange final selectors.
The district is served by an underground cable scheme. Sixty nine cables of paper-core lead covered type enter the building from Rose Street and terminate on the main distribution frame. Some of these cables contain as many as 1,000 pairs of wires, the total number of pairs of wires terminated being 20,000. Long-distance cables entering the exchange include those from London, Leeds, Newcastle, Glasgow, Dundee, and Aberdeen.
The Edinburgh automatic exchange system is operated from 60-volt secondary cell batteries and the power plant at Edinburgh Central includes two 30-cell batteries of 4,000 ampere-hour capacity, with provision for extension to an ultimate capacity of 6,000 ampere-hours. There are also 11 counter E.M.F. batteries for adjusting the power supply to private branch exchanges. Two 105 h.p. d.c. motor generators, capable of delivering 1,000 amperes at 69 volts are provided for charging the batteries. These motor generators are driven from the Corporation 460-volt and 230 volt d.c. supplies. The ringing current for the exchange is furnished by two 75-volt 2-ampere ringing generators, one of which is driven from the public supply mains, and the other from the exchange battery. There are also 20 motor interrupters which provide current for driving the selectors. These machines are located on racks in the automatic switch room.
The work of routine testing the whole of the switching apparatus in an automatic exchange involves much time and labour when carried out entirely by manual methods, and recently much of it has been transferred to automatic routine testing machines, known as "Routiners." The Routiner tests all selectors, one by one, for electrical and mechanical operation. If a switch is defective the Routiner automatically stops, switches an alarm into circuit, and indicates by means of lamp signals the type of fault existing. As the routine testing of the "two-motion" selectors constitutes a very large percentage of the total routine testing in the exchange, a great saving of labour has been effected by the introduction of these machines. Routine testing has not yet been introduced at the satellite exchanges.
All calls not completed wholly by automatic switching are dealt with in the manual switch room situated on the top floor of the building. From this switch room there are direct lines to London, Glasgow, Carlisle, Perth, Dundee, Dumfries, and to sixty-two other exchanges having a community of interest with the capital. The main features of the manual switch room are the long-distance trunk positions, the "A" and "B" positions, and the monitor's desk. At the "A" positions calls for exchanges other than for long-distance centres are completed. When a caller dials "0" a lamp glows; an operator answers, records particulars of the call and immediately establishes communication with the distant exchange. The calling equipment is repeated at convenient intervals over the whole suite of positions. By this means a calling signal appears in sight of a large number of operators and a prompt answer is thus ensured. At these positions calls are timed from "Veeder" clocks. This type of clock is operated electrically and shows the timing to decimals of a minute.
The "B" positions are switching points for calls from and to exchanges which have no direct communication with each other, and for incoming calls to subscribers in the automatic area from exchanges which do not obtain them by dialling direct.
At the monitor's desk inquiries and complaints are received. A specially trained team is employed here which has at hand telephone directories for all exchange areas in the British Isles as well as other books of reference and records in card index form, so that subscribers may be furnished with any desired information without delay. If it is found necessary to refer an inquiry to a distant exchange this is done by the monitor without charge to the caller. All complaints are recorded on special dockets, which are passed to the engineering officers for attention.
A new and important development of the public telephone service is the introduction of the "Demand System" of working. The installation of the necessary equipment for this is nearing completion. Under this system long-distance calls which are at present dealt with on a delay basis will be completed while the caller waits, i.e. retains the receiver to the ear. One of the interesting features at the "demand" positions is the provision of "chargeable time indicators." This timing device is started by the controlling telephonist when satisfactory conversation is heard to commence. When the subscriber replaces his receiver the timing mechanism stops; the telephonist then operates a key which causes the chargeable duration of the call, in minutes, to be displayed on an illuminated screen on the face of the switchboard.
Another recent innovation is known under the title "Telex" service whereby typewritten messages can be sent over the public telephone system. A "Telex" subscriber (i.e. a telephone subscriber with teleprinter apparatus) can make an ordinary telephone call to another "Telex" subscriber and typewritten messages can then be passed between them. A confirmation copy of the message is automatically typed on the sender's machine. The calls are connected at a special "Telex" position in the Edinburgh manual switch room.
MESSRS. REDPATH, BROWN AND COMPANY, ST. ANDREW STEEL WORKS.
The firm of Redpath and Brown was established in Edinburgh in 1802 to conduct the business of wholesale ironmongers, nail makers and iron merchants. In 1820 the style of the firm was altered to Redpath, Brown and Company, when Mr. James Marshall was assumed by Mr. John Redpath and Mr. John Brown as a partner. Mr. James Marshall was associated with the business, first as an apprentice and afterwards as Principal, from 1812 to 1873, a period of sixty-one years, but this record was eclipsed by his nephew, Mr. John Cowan (afterwards Sir John Cowan) who joined the firm as an apprentice in 1860. At the time of his death in 1929 his service to the company had covered a period of nearly sixty-nine years. Mr. Brown, one of the original partners, was a pioneer in the design of wrought-iron suspension bridges. A wire suspension foot bridge of 110 feet span over the Tweed near Peebles, which is still in use, is one of the earliest on record, and was constructed to Mr. Brown's design in 1817.
It was not, however, until about 1880 that the firm, under the direction of Mr. John Cowan as sole partner, opened a department for iron constructional work such as beams and roof trusses. At first, operations were on a small scale, but they gradually increased, especially after the introduction in 1885 of mild steel rolled joists. In the following year the firm made some steel joist compound girders, the first in Scotland. Ten years later, in 1896, the company was incorporated, the late Sir John Cowan being the first chairman. The present site of the St. Andrew Steel Works was acquired and workshops, equipped with the latest plant available at the time, were constructed. (None of the shops erected in 1896 is now in existence.) The company now specialized in steel construction for buildings, and it was among the first to substitute steel stanchions for cast iron columns. During the next ten years it supplied the steelwork for the first steel skeleton buildings in England, Scotland, and Ireland.
The St. Andrew Steel Works, Edinburgh, are typical also of the firm's other works in London, Manchester, and Glasgow. There is a large stockyard containing the various sections and plates used in steel construction. Adjacent to the stockyard is the cutting department equipped with modern high-speed saws. At the other end of the works is a large template loft, and in the main shops are the platers' benches (with individual automatic hoists), drilling, shearing, and riveting machines, together with finishing tools such as planing and girder-ending machines.
Electricity is the general motive power, but hydraulic and pneumatic power are also used, together with oxy-acetylene and arc-welding plant. There is a large assembling and erecting shop and painting is usually performed by pneumatic sprayers.
MESSRS. HENRY ROBB.
The firm's shipbuilding and repairing yard at Leith is similar to most shipbuilding yards devoted to the construction of miscellaneous vessels of the smaller type. The works include an oil-fired furnace for bending plates and angles, rollers for bending and setting plates, punching machines, and a large sawmill. There are six building slips capable of accommodating vessels up to 300 feet in length. They are fitted with modern electric cranes.
THE ROYAL SCOTTISH MUSEUM.
The Royal Scottish Museum, which was founded in 1854 under the name of the Industrial Museum of Scotland, is situated in Chambers Street, Edinburgh, and is under the control of the Scottish Education Department. The collections dealing with engineering, mining, metallurgy, and cognate subjects form a separate section of the museum, under the title of the Technological Department, and are being developed with the special view of affording facilities to students of these subjects. The collections are arranged in two large halls on the ground floor and in two galleries on the second floor. Many of the models are of great historical interest, whilst those of modern machinery have been made mainly in the workshops of the museum. The following notes refer to the more important exhibits.
Amongst the steam engines are the Wylam Dilly locomotive, built in 1813, a Watt engine with sun-and-planet motion, of 1786, and a quarter-size model of a 1,000 h.p. triple-expansion engine, made in the workshops of the museum from drawings supplied by Messrs. W. H. Allen, Sons and Company of Bedford.
In the railway transport section, models of various leading types of locomotives are shown as well as numerous examples of historical permanent way, and a specially fine exhibit illustrating Westinghouse, vacuum, and steam brakes. Through the kindness of various firms of boilermakers, who have presented models, boilers are also well represented.
Aeronautics are illustrated by the glider on which Pilcher carried out experiments near Glasgow, a number of model gliders, aeroplanes, and balloons, and a collection of British and foreign aeroplane engines, including a very early example presented by the Wright brothers. An exceptionally complete collection of electric lamps includes examples of original Lane-Fox, Swan, and Edison lamps, and the first gas-filled lamp made in Britain, by the British Thomson-Houston Company in 1913.
A special feature of the naval and maritime collections is the fine series of models of ships and marine engines. Among the models are representative Mediterranean, Viking, and early British craft, gradually working down through Elizabethan ships to examples of sail-o'-the-line and clipper merchantmen. Typical examples of steamships and marine engines show the development of a great modern industry.
The collection of models of lighthouses and lighthouse apparatus, shown in the Civil Engineering Gallery, is, owing to the generous co-operation of the Commissioners of Northern Lighthouses, the finest in the world; it contains specimens of every type of optical arrangement from the wooden paraboloid, lined with pieces of mirror, to the latest arrangements of optical glass, the first mineral oil burner, and a specially interesting series of models, made by John Smeaton himself, of the various lighthouses which have stood on the Eddystone Rock before he built his lighthouse there in the year 1759. In the same gallery is exhibited a series of models which illustrate various important types of bridges, including examples from the historic Coalbrookdale iron bridge to the latest structures in steel and ferroconcrete. Water supply is also dealt with in this gallery by models of filters, sand and mechanical, catchment areas, embankments, etc.
The mining collection illustrates mainly Scottish practice in coal mining. Three large glass models of the Mid Lothian and the Fife coalfields, and the Lothian shale field give an instructive representation of these economically important areas. Colliery surface arrangements, including steam and electric winders, screening and washing plant, etc., are very fully dealt with.
The peculiarly Scottish industry of shale mining and distillation is well represented by specimens of the original products made by Sir James Young, the founder of the industry, many models of the plant used, and specimens of modern manufacture presented by Messrs. Scottish Oils of Glasgow. Apparatus for rescue work in mines is very completely represented.
The metallurgical exhibits deal mainly with the manufacture of iron and steel in Scotland, and consist of models of furnaces and other plant, specimens of the various products, etc. Two interesting items are a pig of iron made in Strathspey in 1729, which has the date cast on it, and a crucible-steel locomotive tyre made by Messrs. Cammell in 1876.
There are also valuable and extensive collections in the Museum under the charge of the Keepers of the Art and Ethnographical and Natural History departments. Temporary exhibitions are held from time to time in the Museum, and at present the fine collection of aircraft models belonging to the Department of Overseas Trade is on exhibition. This collection gives a complete survey of the development of the heavier-than-air machine and has been exhibited in several of the great international exhibitions throughout the world.
UNIVERSITY OF EDINBURGH, DEPARTMENT OF ENGINEERING.
The Chair of Engineering in the University of Edinburgh was instituted by Sir David Baxter, Bart., in 1868, its first occupant being Professor Fleeming Jenkin, F.R.S. Amongst the students in those early days were William Hole and Robert Louis Stevenson who, in his own words, "acted upon an extensive and highly rational system of truantry which cost him a great deal of trouble to put in exercise." During the sessions 1871-3 the prizeman was James Alfred Ewing, later to become Principal of the University, an honoured Member of the Institution who received the freedom of his native city, Dundee, on the occasion of the visit of the members to that city on 31st May.
The Chair was occupied from 1885 to 1901 by Professor G. F. Armstrong, who established a laboratory in the basement of the Old College, and this condition still prevailed when the present occupant of the Chair, Sir Thomas Hudson Beare, D.L., M.I.Mech.E., was appointed in 1901. Under Sir Thomas Hudson Beare a new department was established at High School Yards in a building which had previously been the High School of Edinburgh. As a result of this expansion there was a rapid increase in the number of engineering students, and by 1925 the accommodation was taxed to its utmost extent.
In 1927, under the will of the late Mr. James Sanderson of Galashiels, the University received a bequest of £50,000 and decided to devote it to meet the costs of the erection and equipment of new engineering laboratories.
Sanderson Laboratories. — The new building forms part of the King's Buildings of the University and is situated in Mayfield Road. It is oblong in plan, 200 feet in length and 144 feet in breadth. The front portion is two-storied and contains the lecture theatre and class rooms on the ground floor, and the drawing office, library, and staff rooms on the upper floor. The rear portion is subdivided to form laboratories, boiler house, and workshops. A tower, 80 feet high, serves the dual purpose of chimney and water tower for supplying the hydraulic laboratory.
Strength of Materials Laboratory. — The plant forming the principal equipment of the laboratory consists of a 100-ton Buckton testing machine with pump and accumulator; two 10-ton hand operated Buckton testing machines; a 60,000 lb. gear-driven Riehle testing machine; a 120-ton Amsler compression and bending testing machine; a 10,000 lb. Olsen wire and strip-testing machine; a 10,000 in.-lb. Buckton torsion machine; a 2,000 in.-lb. torsion machine; a 2,300 lb. Adie cement testing machine; a Haigh alternating stress machine; an Olsen cast iron beam tester; a 23 ft.-lb. Izod impact testing machine; a Brinell hardness tester; and apparatus for tests on combined bending and torsion. The preparation of test pieces and cubes for cement and reinforced concrete testing is carried out in a laboratory specially constructed for this purpose.
Boiler House and Heat Engines Laboratory. — The steam boiler is of the Yarrow type, coal fired by hand, and capable of evaporating 6,000 lb. of water per hour at 250 lb. per sq. in. pressure. A steam superheat temperature of 175 deg. F. is obtainable, and the plant is so arranged that superheated steam or saturated steam may be obtained simultaneously in any desired proportions. The steam units installed at present include the following: a 15 b.h.p. turbine dynamo of the single-stage De Laval geared type; an open type compound high-speed vertical engine of 15 b.h.p.; and a 40 b.h.p. horizontal compound engine; all having separate surface condensing plant placed in a pit 4 feet below the main laboratory floor.
The equipment of the laboratory also includes two gas engines of 20 b.h.p. and 7 b.h.p. respectively, two oil engines also of 20 b.h.p. and 7 b.h.p., a 25 b.h.p. "Albion" petrol engine direct coupled to a Macfarlane electric dynamometer, and a six-cylinder Leyland compression-ignition engine of the very latest type fitted with a suitable apparatus for determining the horse-power.
Hydraulics Laboratory. — The floor of the hydraulics laboratory is laid out on two levels. The equipment on the upper level is arranged so that experiments may be made on the flow of water through orifices, on losses in pipes, bends, sudden enlargements and contractions, and on the pressure of water on vanes. There are also two Pelton wheels and a reaction turbine on which brake tests may be made.
The water from this apparatus is led into drainage channels from which it flows to large measuring tanks below the floor at the lower end of the laboratory. An open concrete channel, 30 feet long and 3 feet wide, runs the whole length of the upper level. This channel may be used for current meter experiments, and discharge takes place over a notch into the measuring tanks. On the lower floor are placed two centrifugal pumps, one having two stages, and of capacity 400 gal. per min. at a head of 100 feet, and the other, three stages, of capacity 350 gal. per min. at a head of 250 feet. These pumps are available for testing.
Water is supplied to the laboratory either from the pumps or from a storage tank of 6,500 gallons capacity in the tower, at a head of 70 feet. There is also available a main water supply through a 6-inch pipe under a head of 125 feet. Each piece of apparatus in the laboratory is provided with a gauge of either Venturi or orifice type, making it a self-contained unit so that several experiments may be carried on simultaneously.
Machines Laboratory. — The equipment in the machines laboratory consists of apparatus for experimental work on moments of forces, couples, and the centroids of areas. The operation of machines and the calculation of their efficiency is carried out with the Duplex screw apparatus, Weston pulley blocks, rope pulley blocks, single-purchase crab winch, double-purchase crab winch, and the worm and wormwheel. Machines are also installed for determining the friction of ropes and belts, the moment of inertia and radius of gyration of flywheels and the whirling of shafts.
MESSRS. WILLIAM YOUNGER AND COMPANY, HOLYROOD BREWERY.
The company was established in 1749, and ranks among the largest brewing firms in the country. Water is obtained from the company's own wells, four in number, each fitted with duplicate electrically driven pumps automatically operated by float switch. The wells are 200 feet deep, and each set of pumps can handle 18,000 gal. per hour. The water-heating equipment has a capacity of 70,000 gal. per hour raised in temperature from 50 deg. to 212 deg. F. and is fire-heated in addition to being steam-heated by a calorifier fitted with automatic temperature regulation. Wort-boiling coppers, of which there are ten of 90 barrels capacity each, are fire-heated. Cooling the wort is carried out over twelve refrigerators, from which it runs by gravity to any of the 136 fermenting vessels. From the fermenting vessels the beer gravitates to the racking squares and to cask.
Yeast is collected in aluminium vessels, of which there are 30, pressed and stored in a building specially built for the purpose. Duplicate laundry washing machines and hydro-extractors are used to deal with the cloths from the yeast filter presses. Absolute cleanliness is essential in the brewing industry and every precaution is taken to attain this object.
Bottling is carried out with plant of the latest type. There are two 8-ton ice-making machines for chilling purposes in this department. The cooperage is capable of handling 2,500 casks per day, and great care is exercised to obtain clean and sterile casks. The maltings are capable of making 100,000 quarters per season, and modern types of barley- and malt-handling machinery are installed. Motive power in the maltings is both electric and steam.
Steam is used principally for process work at 60 lb. per sq. in. pressure and is generated in eight Lancashire boilers 30 in. by 7 ft. 6 in. and three Cochran boilers 14 ft. 6 in. by 6 ft. 6 in. The laboratory is very well equipped and is of the greatest value in controlling the processes of the brewery. The total number of electric motors installed in the breweries and maltings is 140. The company has its own works department for carrying out building and general engineering work.
MESSRS. WILLIAM BRIGGS AND SONS, DUNDEE.
Oil from Venezuela, Mexico, Trinidad, and other sources is pumped direct from the arriving tank steamers through a pipe line to the storage tanks at the firm's Camperdown bitumen refinery. In the process of refining the oil is heated in a tube still by means of an oil-fired furnace. The vapours pass into a fractionating tower kept under vacuum. The light vapours are drawn off at the top and condensed to form Diesel oils, while the heavier vapours, which form lubricating oils of various specific gravities, are drawn off lower down. The residuum is pure bitumen. The bitumen is dispatched whilst hot in special insulated railway tank wagons, or, when required, in steel drums.
MESSRS. CAIRD (DUNDEE).
Raw jute, an annual plant which grows 8 to 16 feet high, is packed before export from Calcutta by means of hydraulic presses into "bales" weighing approximately 400 lb. each. The first process at the Ashton Works is "batching," in which the jute is sorted to fulfil three conditions: cost, the right blend of grades to obtain uniform quality and colour, and the proper assortment to suit either warp or weft yarn as required. The bales are then opened up by a special machine and the heads split up into "stricks" weighing about 2 lb. each. These are fed into the jute softener, in which they pass through a long series of fluted rollers whilst oil and water are dropped from above. The fibre is then allowed to stand for forty-eight hours. After weighing into what are known as "dolop lots" it passes through a combing process, the action of which depends upon the relative speeds of various rollers and the angular direction of the pins along and around the rollers. The fibre is delivered in the form of a "sliver" or riband into cans and then passes through a "finisher card" in which it is combed to a finer degree. The next process is "drawing." It is a further combing process but is carried out on drawing frames having gill pins differing only in general arrangement from those of the carding machines. Several types of drawing frames are used according to the class of jute and the yarns required. Four ends or slivers are carried in at the back of the machines and delivered as one at the front. Two of these single slivers are then passed through a second drawing machine having still finer pins and are further combed and drawn out and delivered as one.
The final process of preparing the fibre for spinning is called "roving" and in this operation each sliver passes separately through the machine. The fibre is further drawn and as it is delivered at the front of the machine it receives a small amount of twist to strengthen it. Thus it can be successfully wound by means of the flyer upon the roving bobbins. The rove yarn thus produced is transferred to the spinning frames, in which the original twist is unwound to permit of the rove being drawn before it receives a permanent twist prior to being wound upon the spinning bobbin. Certain yarns are twisted harder to give the "warp," whilst the softer twist gives the "weft." The yarns are next wound upon spools and are transferred to the dressing machines. The weft yarns are taken to the "cop" winding machine and wound into "cops" ready for manufacture into cloth by means of shuttles.
The first process in the weaving department is to prepare the warp yarns by dressing or starching them on the dressing machines. The yarn is drawn from spools revolving in banks through a back reed which keeps the threads at a uniform distance from one another, after which the threads pass between two dressing rollers, one of which revolves in starching mixture. The threads pass along to and round the drying cylinders, which are heated by steam.
Every woven fabric is composed of two systems of yarn—warp and weft. The warp runs lengthwise, and consists of a large number of threads, or ends, according to the build of the cloth required, and those threads of warp are all wound tightly upon the yarn beam. Before the yarn beam is taken to the loom the different threads have to be drawn through heddles in the leaves of the "camb." The camb consists of a series of leaves, the number of which is determined by the nature of the weave of the cloth. The camb is fixed upon the loom, and the mechanism is arranged to control these leaves so that a shed or opening formed by the warp threads allows the shuttle to pass through and interlace the weft threads in the form of cloth. The weft is made up in the form of cops or pirns. Each of these is singly inserted into the shuttle, which is propelled by a picking arm, and passes through the shed made by the operation of the camb leaves. Before the loom is put in action the threads have been drawn forward and attached to another roller at the front of the loom, known as the cloth beam, and upon this beam the woven material is automatically wound after the actual cloth weaving is completed. After a certain length of cloth is woven and wound upon this cloth beam, the beam is taken out and the cloth unwound by means of a stripping machine.
The cloth is now taken to the finishing house and after inspection of the surface is passed to the cropping machine where the projecting fibres are removed. All jute fabrics, with very few exceptions, are damped prior to the actual finishing process, after which the cloth is rolled up as tightly as possible and allowed to lie in this condition for a period of 24 to 48 hours. The essential difference between the subsequent operations of calendering and mangling lies in the fact that in the former finishing process every inch of cloth is subjected in regular succession to the comparatively heavy but somewhat momentary pressure during its rapid passage between the rolls of the machine, whereas in mangling the whole piece of cloth of about 100 yards in length is first beamed hard round an iron roller, called a "pin," then placed into position between the "bowls" of the hydraulic mangle and for some time subjected to a continuous heavy pressure. During the actual mangling process a reversing motion comes into operation, which has the effect of causing the rollers of the mangle to rotate alternately in different directions. This alteration of the direction of rotation under the heavy pressure employed, coupled with the fact that the pressure is imparted practically to the whole piece through the medium of the layers of the cloth itself, directly accounts for the characteristic finish of mangled cloths. The object of calendering is to flatten the threads before placing the material in the mangle. Finally the material is accurately measured by machine and rolled or lapped for dispatch.
MESSRS. D. CALLANDER, CUNMONT QUARRY, ANGUS.
Cunmont Quarry is situated about 8 miles from Dundee, and some 1.5 miles from Kingennie Station. It is within easy reach of a part of Scotland noted in history for its association with General Claverhouse, "bonnie Dundee" of Covenanting times. A fine view of the Firth of Tay and the coast of Fifeshire is obtainable from the Quarry, which is cut into the east side of Cunmont Hill. The engineering equipment at Cunmont has all been installed within the past three years, and incorporates many labour-saving devices, as for example, the electrically heated tar boiler, with automatic temperature control, which requires no attendance whatever, the magnetic pulley for automatic removal of tramp iron or hammerheads from the stone, and numerous conveyers which transport the stone from point to point without requiring labour.
The primary crusher is noteworthy. It is capable of crushing 1,500 tons per day to 6-inch size. The method of lubrication used in the bearings is unusual, grease and water being employed. The top halves of the bearings have annular spaces to receive a large quantity of grease, water connexions being made direct to the bearings.
Electric power for driving the machinery is taken from the mains of the Grampian Electricity Supply Company, at 11,000 volts, and is transformed to 440 volts, three-phase, 50 cycles per second. The entire output of the quarry consists of whinstone, which is crushed and graded into various sizes from 2.5 inches down to 1/8 inch. The product is used solely for road work, a considerable quantity being sent as far afield as the South of England. The plant is capable of an output approaching 1,000 tons per day of crushed stone, of which about 350 tons can be converted into tarmacadam.
An interesting design of oscillating screen is in use, which gives very fine separation of the various sizes of stone, while consuming much less power than the old rotary type. The dust-extraction plant which is in operation collects several tons of fine stone flour per day, the flour being bagged and used in the making of asphalt, etc. The methods of storage and handling of crushed stone are of special interest, large reinforced concrete bins of 3,000 tons capacity being employed and supplemented by bins of material which are dumped and lifted by means of a three-motor electric travelling crane on a gantry.
MESSRS. DONALD BROTHERS, DUNDEE.
The firm have been manufacturers of linen in Dundee and the neighbourhood since the days of hand-loom weaving. About forty years ago they turned their attention to the production of furnishing, decorative, and needlework fabrics. Their works are situated in Old Glamis Road, and are only a few miles from Glamis Castle. With the permission of the Earl of Strathmore they adopted a picture of the Castle as their trade mark, and their fabrics are now known as Old Glamis Fabrics. The Duchess of York and Countess of Strathmore visited the works some years ago and the firm reproduced certain fabrics, from rare and old pieces, loaned by the distinguished ladies.
THE DUNDEE FLOORCLOTH AND LINOLEUM COMPANY, DUNDEE.
The company was formed in 1901. The buildings are of brick and ferroconcrete with large open floor areas, and include commodious warehouses for both finished stocks and raw materials. Within the past ten years extensive additions and improvements have been made to the plant and buildings, including a general reconstruction of the power plant, which have not only resulted in modernized methods of production, but have opened up the way for the manufacture of other important floor-covering productions. The whole of the plant is now electrically driven, and power is economically generated by high-speed steam generator sets.
DUNDEE TECHNICAL COLLEGE AND SCHOOL OF ART.
The Dundee Technical College and School of Art is the central institution for technical and art instruction for Dundee and the surrounding districts of Angus, Fife, and Perthshire. The present building in Bell Street was erected in 1910 at a total cost of £80,000 for site, buildings, and equipment to replace an earlier Technical Institute situated in Small's Wynd, adjacent to University College, which owed its inception to the generosity of the late Sir David Baxter, Bart., of Kilmaron, merchant in Dundee, who died in 1872.
The institution provides full day and evening courses of instruction in many technical subjects and in art suited to the requirements of students employed in the industries and trades of the locality. The college is under the supervision of the Scottish Education Department, and is maintained by class fees, endowment, and grants from the Department and the Education Authorities of the districts from which students are drawn.
The School of Engineering is an extensive one, the enrolment amounting to 800 students under normal conditions of trade. The lecture rooms are situated on the first floor, where space is also provided for the suite of classrooms for machine drawing and design. The large junior room has places for 64 students. The mechanical and electrical laboratories are located on the ground floor together with the boiler house and workshops. The Textile Department is accommodated in a separate building in the rear quadrangle; the spacious spinning and weaving sheds are fully equipped with the different types of frames and looms necessary for the complete demonstration of the various practical processes of jute and linen manufacture from raw material to finished product.
THE NORTH BRITISH LINOLEUM COMPANY, DUNDEE.
Although one of the youngest British linoleum manufacturing firms, it possesses one of the best equipped linoleum factories in the world. The buildings occupy 4.5 acres, and the layout of the departments has been planned to give a continuous progress from the raw material to the finished product. Bales of cork are imported from Spain and Portugal, and the contents are first passed over a magnetized bed to extract the metallic substances often found in virgin cork. The cork bark is then broken into pieces of standard size in a disintegrator, and dust and foreign matter are removed by air extraction. The cleaned cork then passes to the "hurstings," massive machines which grind the cork to powder. The powder is then graded into varying degrees of fineness by centrifugal machines.
From the cork grinding department the material passes to the mixing tower, 80 feet high. It has six storeys and is served by an electric lift. Each floor carries a mixing machine through which, beginning on the top floor, the mass to be mixed passes by gravitation until it finally emerges on a steel band roller which feeds the calender. The latter weighs about 140 tons, and is electrically driven. It travels along rails the entire length of the building. In this machine the linoleum mass is subjected to extreme pressure, and is keyed on the jute hessian backing which forms the base of most linoleums. This machine conveys the linoleum direct to the drying rooms, where it is allowed to remain at varying temperatures until finally seasoned. These drying rooms are about 140 feet long and 50 feet high, and when loaded resemble the "gridiron" over a theatre stage. When fully seasoned, the cloth is tested and thereafter removed to the trimming departments for final inspection before dispatch.
MESSRS. D. C. THOMSON AND COMPANY, DUNDEE.
The firm are the proprietors of a number of newspapers and periodical publications, and at their Dundee offices practically every feature of engineering interest connected with the collection and dissemination of news and the publication of magazines may be seen. The composing room is on the top floor so as to have the advantage of roof lighting. Underneath the main machinery hall, where the printing presses are housed, there is a power house in which electrical power is generated by gas engines. There is also a complete engineering workshop to enable repairs to be carried out instantly.
UNIVERSITY COLLEGE, DUNDEE, UNIVERSITY OF ST. ANDREWS. DEPARTMENT OF ENGINEERING.
Founded in 1881, University College, Dundee, was united to the University of St. Andrews in 1890. The union was dissolved in 1895 but reconstituted in 1897, since when the college has formed an integral part of the University. The Chair of Engineering was one of the first to be established, and in 1882, Professor (now Sir Alfred) Ewing was elected as its first occupant. He was followed in 1891 by T. Claxton Fidler, on whose resignation in 1909 Dr. A. H. Gibson, M.I.Mech.E., was elected. In 1920 he was succeeded by the present Professor of Engineering, Dr. A. R. Fulton.
During the last twenty-five years new buildings for the accommodation of the Engineering Department have been erected, and modern equipment installed.
Strength of Materials Laboratory. — This includes a 50-ton Wicksteed machine, Ewing's and Lamb's extensometers, an alternating stress machine, spring and gauge testers, Herbert and Vickers hardness testers, an Olsen torsion testing machine, and apparatus for the testing of struts and investigating the elastic vibrations and deformations of structures. A special section is set aside for the testing of cement, and contains machines for moulding and testing concrete beams, columns, and slabs.
Hydraulics Laboratory. — There is an extensive equipment of turbines and centrifugal and reciprocating pumps, apparatus for experimental work on a large scale on notch, weir, and channel flow, on the flow of water through pipes and orifices, on the impact of jets, and on problems of water hammer.
Heat Engines Laboratory. — A horizontal compound steam engine develops up to 150 i.h.p., and there are a 50 h.p. steam turbine, a Babcock and Wilcox boiler with superheater and economizer, a "National" gas engine and producer, a Ruston and Hornsby cold-starting, solid-injection oil engine, a Heenan and Froude brake, an air compressor, and apparatus for the accurate determination of the calorific values of solid, liquid and gaseous fuels, and for the analysis of flue gases.
The Peters Electrical Laboratory. — The equipment includes a range of apparatus for the demonstration of the principles of electricity and magnetism, and for measurements and testing. Standardizing apparatus comprises direct- and alternating-current potentiometers, a mutual inductometer, standard resistances, inductances and condensers, a Kelvin balance, a magnetic standard, photometric standards, and other components. A steady direct-current source is furnished by a 230-volt battery of 125 ampere-hours capacity, subdivided into ten sections. The machine laboratory includes three motor-alternator sets and a rotary converter, arranged for parallel running in various combinations. One of the machines is a sine-wave alternator for iron testing, and a frequency range of 20 to 80 cycles per second is obtainable. There are also shunt and series direct-current Hopkinson sets, single- and three-phase alternating-current commutator motors, dynamometers for electrical and mechanical load tests, transformers, voltage regulator, and frequency changer. The equipment has been kept flexible to enable various special combinations to be obtained. A high-frequency electromagnetic oscillograph gives either visual or photographic recording on all apparatus, and a high-frequency generator is in process of being installed. High-tension direct current at 20,000 volts is supplied by a valve rectifier. The laboratory is well equipped for sensitive measurements as well as for practical testing.
MESSRS. PETER ANDERSON, BRIDGE MILL, GALASHIELS.
The business carried on by Mr. Peter Anderson was originally started in 1892 in a small weaving shop, where the plant comprised three hand looms and one set of warping stakes, the finished goods being stocked in a room in the house. The firm prospered, and in 1896 removed to a larger flat in Roxburgh Street, which was partly fitted up as a warehouse. Later, all four flats in the building were occupied. Owing to continued expansion of business, Mr. Anderson, in 1907, bought Bridge Mill, Huddersfield Street, which was driven by steam and water power. Warping and weaving only were at first carried on, but later carding and spinning, and finishing were added. To-day, the whole process of tweed manufacture, with the exception of dyeing, is carried on at this mill.
SCOTTISH POWER COMPANY. THE HYDRO-ELECTRIC POWER WORKS OF THE GRAMPIAN ELECTRICITY SUPPLY COMPANY.
Ericht Development. — The Ericht Development was completed in November 1930, provision being made in the present scheme for further development, including the raising of Ericht Dam and adding a third pipe line and generating set; the tunnel was made large enough for this addition to the scheme. The Tummel Development is at present under construction. The Ericht Development utilizes the difference in elevation between Loch Ericht and Loch Rannoch amounting to 485 feet. The catchment area in the present development is 75 square miles, and the storage area of Loch Ericht is 7.15 square miles, giving a storage of 3,425,000,000 cu. ft. or 28,820,000 kW.-hr.
The natural water level of Loch Ericht has been raised 14 feet by the Ericht Dam, which is a concrete gravity dam, and a channel 1.5 miles long has been excavated from Loch Ericht to the dam to draw down 5 feet below the previous natural water level. The water is drawn off at the intake tower inside the dam and passes through screens down a vertical shaft and through a gate at the entrance to the tunnel. The tunnel, which is 12 ft. 4 in. diameter inside the concrete lining, conveys the water for a distance of 2.75 miles to the portal and valve house at the top of the pipe line, and on the route crosses the River Ericht by means of a steel pipe 11 ft. 10 in. in diameter. Near the portal a surge shaft 192 feet deep and 45 feet in diameter is connected to and above the tunnel to balance the varying demands for water from the power house.
Before the tunnel comes to the surface at the portal, it branches into two smaller tunnels each 10 ft. 6 in. diameter, and each of these branches again into two steel pipe lines. These are each 7 ft. 10.5 in. diameter and 2,700 feet long, two being already constructed and provision made for adding a third. The pipe lines were made up in lengths of 24 feet, three plates to the circumference, water-gas welded in the shop, and the pipe joints were riveted at the site.
The pipe line is supported at 48-foot intervals on concrete pedestals with steel rollers to allow for expansion and contraction under varying temperatures, and is anchored by heavy concrete blocks about 600 feet apart. Expansion joints of the stuffing box type are situated immediately below each anchorage. The thickness of the steel pipe shell varies between 0.5 inch and 0.875 inch. At the bottom of each pipe line, before it enters the power house, a Venturi meter is provided to measure the quantity of water. Each pipe line drives a turbine of 22,000 h.p. and then enters the tail race, which consists of a large concrete-lined channel about 400 feet in length, leading the water into Loch Rannoch.
The power house is a steel-framed structure with concrete block work walls 100 feet long by 60 feet wide by 46 feet above alternator floor level, and contains two vertical generating sets each of 22,000 b.h.p. The alternators generate at 11,000 volts, three phase, 50 cycles per second, and run at 500 r.p.m. The outdoor substation contains two 20,000 kVA. transformers, transforming from 11,000 to 132,000 volts with two boosters; also two 5,000 kVA. transformers, transforming from 11,000 to 33,000 volts.
The 132 kV. transmission line extends from the Rannoch Power Station to Abernethy, a distance of 58 miles, and is carried on steel towers averaging 97 feet high with spans of 900 feet to 1,500 feet. The 33 kV. line extends to Arbroath, a distance of 74 miles, and is a wood-pole "H" type line.
Tummel Development. — The Tummel Development is at present under construction and is situated below the Rannoch power house. It utilizes the area of Loch Rannoch, amounting to 7.35 square miles, as a water storage area, and the catchment area including the area in the Ericht Development already constructed amounts to 284 square miles.
The outlet to Loch Rannoch is the River Tummel which commences at Kinloch Rannoch, and at this point a control weir is being constructed to regulate the water level of the loch and give a depth of storage of 8 feet. From this point the water will be passed down the river as required to the reservoir to be formed by the intake dam about 5 miles down the River Tummel. For this purpose the River Tummel, both above and below the control weir, for a distance of about 5,000 feet, has been deepened and the foundations of the Kinloch Rannoch masonry arch road bridge, built in 1760, have been protected against scour.
At the intake dam there is enough storage to balance the fluctuations in the daily demand for water by the power station. The dam is a concrete structure on rock foundation and has two large steel sluice gates, each 25 feet square, to pass flood water. There are also four automatic syphons to keep the water level from rising more than a limited amount during floods. A fish ladder, consisting of twenty-three pools, is provided to enable fish to proceed above the intake dam.
On the south bank the water is taken off through screens into the Tummel Aqueduct which follows a contour along the hillside for a distance of about three miles. It consists of a concrete-lined channel on a gradient of 1 in 3,200, varying in water depth from 11 feet to 15.5 feet, and in water surface width from 51 feet to 80 feet at the forebay at the lower end. The aqueduct has been formed by excavating along the hillside and forming a bank on the lower side. At the forebay the water will pass through screens and enter two steel pipe lines each controlled by a steel sluice gate 12 ft. 6 in. square. Each pipe line is 12 ft. 6 in. in diameter and 650 feet long, and is supported at 32-foot centres on roller bearings and anchored by a large concrete block between the forebay and the power house. The expansion joints are of the stuffing box type.
Before entering the power house each pipe line is provided with a Venturi pipe for measuring the flow. The head is 170 feet and there are two horizontal generating sets each of 24,000 h.p. generating current at 11,000 volts, 50 cycles per second, three phase at 300 r.p.m. The capacity of the overhead electric crane is 120 tons. The current passes through the substation into the 132 kV. transmission line from the Rannoch power station.
The power house is a steel-framed structure 175 feet long by 90 feet wide by 50 feet high above alternator floor level with concrete block work walls. Over the tailrace a concrete bridge has been provided to take the road.
The works were designed and constructed by Messrs. Balfour Beatty and Company of London; and Mr. W. T. Halcrow of Messrs. C. S. Meik and Halcrow acted as advising civil engineer to the Grampian Company.