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Note: This is a sub-section of 1931 Institution of Mechanical Engineers
The area drained by this pumping plant is approximately 3,000 acres in Burwell Fen, the water being pumped from the low level of the Fen into the higher level of the River Cam. The original drainage plant was installed in 1846, when the Fen was first drained, and consisted of a 50 b.h.p. beam-engine, steam for which was generated by Lancashire boilers. The beam-engine operated a scoop-wheel by direct coupling. The scoop-wheel not draining the Fen to a sufficiently low level, an auxiliary scoop-wheel was fixed in front at a lower level to assist it, which it did successfully. This plant was in operation for some fifty years when the beam-engine and boilers were removed and a 50 h.p. Hornsby paraffin-driven engine was fixed to drive the scoop-wheels. After running for a few years this engine and the scoop-wheels were burned by a fire in the engine-house. A Ruston crude-oil engine was then installed to drive a 24-inch centrifugal pump in place of the scoop-wheels. This plant is now efficiently draining the Fen. As an auxiliary an 80 h.p. suction-gas engine and plant have recently been fixed, this engine being used mainly in times of flood.
The Cambridge Scientific Instrument Company was founded in 1881, registered as a limited liability company in 1895 under the chairmanship of the late Sir Horace Darwin, F.R.S., and incorporated the business of Mr. R. W. Paul with works at Muswell Hill, London, in 1919, changing its name to the Cambridge and Paul Instrument Company. In April 1924 the name was changed again to the Cambridge Instrument Company, and the employees now number nearly 700. In 1922 an associated American company was formed.
The Cambridge Works are concerned mainly with the manufacture of scientific apparatus designed for special purposes, and of mechanical, physical, gas-analysis and temperature-measuring instruments. The Muswell Hill Works deal mainly with electrical instruments.
In the mercury-thermometer shop thermometers covering a wide range of temperatures are made. They include mercury-in-glass thermometers, both of simple and special design, and mercury-in-steel recording and indicating thermometers. Temperature regulators working on the mercury-in-steel principle and pressure recorders are also made. The shop has interesting methods of testing and calibrating the instruments.
The main instrument assembly shop is devoted to the manufacture of most of the temperature-measuring indicators and recorders other than those operated by mercury, and the manufacture of physical and engineering instruments. These include measuring microscopes, comparators, chronographs, Chattock micromanometers, Rosenhain calorimeters, extensometers, Callendar " J " Apparatus, and other special instruments for various applications. The machine shop contains twenty-four capstan lathes, ten milling machines, a large number of drilling machines, and miscellaneous gear for special purposes.
The electrical wiring and assembly shop deals with the mounting and suspending of indicators and recorders, and the construction of thermocouples and resistance thermometers. One department of this assembly shop is devoted to medical and physiological apparatus, and here may be seen electro-cardiographs, polygraphs, alveolar air apparatus, Lucas pendulums, microtomes, muscle troughs, hot-wire sphygmographs, string galvanometers and recording cameras.
In the test room the testing and standardization of most of the apparatus seen in the course of construction in the other departments is carried out.
A research department, on the first floor of the main office building, deals among other things with problems relating to micro-photometry, photo-electric recording, gas-analysis, paper testing, galvanometry, and apparatus for the textile industries, while provision is made for dealing with special problems that arise from time to time in applying scientific instruments to industry.
In an enamelling, polishing and plating shop the enamelling is done by the spraying process, and plating in copper, nickel, silver, and gold is carried out. There is also a packing and dispatch department, with finished instrument and material stores. In the new office building on an upper floor is a spacious mess-room, which is also used for social purposes.
It was under the patronage of Desiderius Erasmus that printing was first begun at Cambridge, by John Lair of Siegburg, or John Siberch as he is known to history. The first Cambridge book was printed by him in 1521, although as early as 1276 there is reference to university "stationers," who made copies of approved texts for the use of students in the University. In 1534, as the result of a petition to Cardinal Wolsey, letters patent were granted to the University by Henry VIII to appoint printers residing within the University to print books of every kind that had been approved by the Chancellor. The first printer, Thomas Thomas, was appointed in 1583, and since his time the office has been filled without interruption. Thomas's Latin Dictionary was famous, for it ran into ten editions between 1587 and 1610. Since the time of Thomas Buck, who was appointed University Printer in 1625, the Press has continuously exercised the privilege of printing both Bibles and Prayer-Books, which it holds in common with the Clarendon Press and the King's Printer.
In 1698 new additions were made to the buildings, new presses were set up, and beautiful types were imported from Holland. Further a body of Curatores Prali Typographici was appointed to represent the University in controlling the working and output of the Press. The present syndicate, comprising the Vice-Chancellor and the Treasurer of the University (ex officio) and fourteen Syndics, is the direct successor of this body.
In 1763 John Baskerville produced his Cambridge Bible which has been described as " one of the most beautifully printed books in the world." In 1831 the building, known as the Pitt Press, was commenced, it having been resolved that part of the surplus fund for erecting a statue of William Pitt should be devoted to this purpose. Many additions and extensions have since been made.
Mr. Bruce Rogers spent the greater part of the years 1917-1919 in Cambridge, and was responsible for the design of such books as " The New Shakespeare " and Sir Thomas Heath's " Euclid in Greek." The present buildings include machine rooms, containing perfectors, Miehle and platen presses; a foundry, comprising a stereotyping and electrotyping department; type storerooms, composing rooms and monotype rooms, where books are set up in all varieties of type— among them Caslon, Garamond, Baskerville, Goudy, Polyphilus, Blado and Fournier—and many languages. Every month an average of over fifty tons of printed matter leaves the warehouse, the greater part of it destined, when bound, for the Syndics' London office, some of it for other London publishers. A library containing a representative collection of Cambridge books dating from 1584 to the present day, and including recent books printed by Mr. Walter Lewis, the present printer, for other publishers, is kept at the Cambridge offices.
It was in 1806 that the Chivers family settled as fruit farmers at Histon, in a district which has an historic association with fruit growing, for it is on record that an orchard was planted there as long ago as the seventh century, by the first Abbot of Ely. Their efforts met with success, and ultimately the time came when the quantity of fruit produced was so great that difficulty was experienced in marketing it, even though supplies were sent far afield by road and rail. The suggestion was then made of preserving the fruit on the spot where it was grown, and in 1873 the first boiling of jam took place in a small barn which still stands on the firm's estates.
From this small beginning has grown up what is now one of the largest factories of its kind in the country, and at the same time the farming side has been extending continually, until to-day the firm has over 6,000 acres under cultivation. This source alone provides the factory each year with thousands of tons of freshly picked fruit, and constitutes the largest fruit-growing concern in the British Isles. In conjunction with fruit farming, the breeding of pedigree stock and utility poultry is carried out on an extensive scale, and many successes are achieved in the show ring annually.
Like jam-making, where fresh fruit is used, fruit canning, which the firm started on a commercial scale thirty-five years ago, is seasonal, and in order to keep the factory going the whole year round other products have been introduced, such as marmalade, table jellies, lemon curd, custard powder, mincemeat and plum puddings, etc. In this way the firm is able to give regular employment to some 3,000 people, and during the busy fruit season the number in the works and on the farms rises to about 4,000.
Much of the machinery used in the factory is designed and built by the firm's staff of engineers. There is, too, a can-making department, where all the cans required for fruit canning are made. Branch factories have been developed at Montrose, Scotland, specially to deal with the canning of raspberries, and at Huntingdon, where the canning of fresh vegetables is commencing this season.
Barrington Works, which were designed by Messrs. Horace Boot and Partners, consulting engineers, were built in 1926, and commenced production in the summer of the following year. They are situated about eight miles from Cambridge, and excavate their raw material from Chapel Hill, which is composed of a deposit of "clunch" and has been used for many generations in the neighbourhood for building. The works employ the "wet" process.
The clunch is dug in the pit from a working face of 35 feet by a Ransomes and Rapier 0.75-yard steam-shovel which unloads into "jubilee" wagons. The latter are drawn up to three wash-mills by rope haulage and tipped directly into them. The mills consist of annular pits 20 feet in diameter. The drive is through a crown-wheel and pinion direct from a line-shaft driven by a 200 h.p. motor. The crown-wheel is mounted on a vertical shaft, by the operation of which steel harrows are dragged round in the "slurry." When it is fine enough it is beaten through the surrounding sieves, formed of perforated steel plates, and passes into a trough leading to three totally enclosed bucket elevators. Three Clarke's separators are employed to ensure that the fineness of the wet material shall be consistent, and any material that will not pass through the 0.75-millimetre screens returns to the wash-mills. From the separators the slurry passes down a chute into a 66-ft. diameter storage tank. To keep the lime content in the slurry constant a second 66-ft. diameter storage tank is used, and from this the kiln is fed.
Each tank is stirred mechanically by a mixer of the "Sun and Planet" type. Three-throw slurry pumps deliver the slurry from one mixer to the other, and to the kilns. The slurry fed to the kilns enters a spoon feeder controlled from the firing floor, and its amount fixes the output of the kiln. Each of the two kilns is 9 feet and 10 ft. 6 in. diameter by 200 feet long, and is driven by a cast-steel spur-ring and pinion through four trains of gearing and a variable-speed motor. The speed can be raised from one-half to one revolution per minute according to the output required. The clinker is discharged into rotary coolers underneath in a white-hot state. The coolers are 6 ft. 6 in. diameter and 67 feet long. The air required for combustion in the kilns passes through the cascading clinker in these coolers and is thus preheated. The cool clinker is delivered into the boots of two chain-link bucket elevators, and passes into two storage bunkers above the cement mills. Beside these are the gypsum bunkers.
Both the gypsum and the clinker are fed into the mills by table feeders. The mills are of the combination type, with three grinding chambers loaded with steel balls. They have an output of 10 tons per hour each to a fineness well within the British Standard Specification. The cement mills are 7 feet in diameter by 36 feet long, with trunnion ends. The coal mill is similar to the cement mills, but is 6 feet in diameter by 30 feet long. It grinds a sufficient quantity of coal for firing both kilns. The powdered coal is blown into the kilns with hot air by variable-speed fans. Both the cement and coal mills are fitted with dust-collecting plants. The raw coal is dried in a rotary dryer 40 feet long, 6 feet in diameter. The hot air from the furnaces passes round the outside of the dryer drum and then through the centre.
After coming from the grinding mills the cement falls into the boots of two elevators of the chain-link bucket type, and is conveyed either to a battery of eight silos having a capacity of 5,000 tons, or across the road by a belt conveyer to a battery of five round silos holding 5,000 tons, and arranged for pneumatic extraction and bagging of the cement.
The works have their own power station, and generate electric power at 550 volts, three-phase, 50 cycles per second. Each unit is driven by a separate motor. Lighting and heating are provided for by three transformers at 200 volts, one in the power station, one in the cement mill, and the third on the kiln-firing platform. The boiler-house is provided with three Stirling five-drum type boilers stoked by Babcock and Wilcox travelling chain-grates. Steam is generated at 250 lb. per sq. in. and is superheated to 616° F. Each boiler is capable of evaporating 20,000 lb. of water per hour. The products of combustion are passed through a Green's ringstay economizer. The power units comprise two turbo-alternators and a standby alternator driven by a reciprocating compound double-valve engine. The works are served by the Barrington Light Railway, which extends to Foxton Station on the London and North Eastern Railway main line. The greater part of the line is practically straight, and where it passes over the river Cam a concrete viaduct 240 feet long has been built.
The maximum capacity of the works is 2,800 tons of cement per week.
Just as there is a field of science related to the practice of medicine or the pursuit of agriculture so there is a field definitely related to the preservation and handling of foodstuffs. The Low Temperature Research Station is devoted to the work in this field, which covers, for example, the chemical and the physical properties of muscle, alive and dead, the physiology of fruit and vegetables, and so on. It is indeed an extension of animal and vegetable physiology and of biochemistry and biophysics in certain definite directions. The equipment of the Station is interesting. Thirty-two chambers are provided in which temperatures from 75° F. to -30° F. can be maintained. To this end three CO2 compressors are fitted, which cool brine in three tanks to -18° F., 12° F., and 32° F. Circulating pumps deliver the brine into distribution headers, where certain quantities of two brines are mixed to approach the temperature required in a particular chamber. The mixed brine then circulates through grids or drums fitted to the walls and ceilings of the chambers, returns to the brine tanks and is cooled again. The temperature of the brine delivery is slightly lower than is required, but thermostatically operated electric heaters are fitted in the chambers to counteract the excess of cold, and this enables the air temperature in the chambers to be maintained within one-twentieth of a degree day and night all the year round.
Air temperatures from -5° F. to -30° F. are obtained in two rooms cooled by direct expansion with a separate CO2 compressor. Observation laboratories are provided alongside some of the chambers. Various laboratories are fitted for chemical, biochemical, physical, biophysical, bacteriological work, etc., and a complete small-scale canning factory is equipped. Experiments with fruit in lots of up to one ton are carried out, while larger-scale experiments with fruit are conducted at the Ditton Laboratory, East Malling, Kent, where one store can hold 120 tons of fruit. Experiments with meat in lots of up to eight hind-quarters of beef are performed, and larger-scale experiments are arranged for at public abattoirs.
The Observatory is situated on the Madingley Road about a mile and a half from Great St. Mary's Church. The main building was erected in 1824, the exact site being chosen so that the transit instrument could be placed in the same meridian as the tower of Grantchester Church, lying 2.5 miles south of the observatory. A brass frame on the tower provided a meridian mark, which was periodically observed in the early years; collimators placed north and south of the instrument now render the use of the meridian mark unnecessary.
The principal instrument in the main building is the Meridian Circle mounted in 1870 during the directorship of Professor J. C. Adams. The object glass is 8 inches in aperture, the focal length being 9 feet, and the mounting is by Troughton and Simms. The principal work undertaken with this instrument was (i) the catalogue of stars lying between 25° and 30° north declination, in conformity with the co-operative plan inaugurated by the Astronomische Gesellschaft; (ii) the catalogue of stars lying in the Zodiac.
South-west of the main building is the Northumberland Equatorial Telescope presented by the Duke of Northumberland in 1835. The object glass by Cauchoix has an aperture of 12 inches and a focal length of 19.33 feet. The mounting, of the English form, was constructed under the supervision of Sir George Airy, then Plumian Professor. In the summer of 1846 the then director, Professor J. Challis, searched for the undiscovered planet Neptune according to the predictions made by J. C. Adams. The planet was observed on at least two occasions, but its unique character was not appreciated at the time - not until the predicted body was observed by Dr. Galle at Berlin in September 1846, and its true planetary nature established. Adjoining is the Thorrowgood Equatorial Telescope, the object glass of 8 inches aperture, on loan for ten years from the Royal. Astronomical Society.
South-east of the Northumberland Telescope is the Sheepshanks Telescope of the Coude type. The object glass, aperture 12.5 inches and focal length 19.33 feet, was made by Mr. Dennis Taylor of Cooke and Sons. The mounting was made by Sir Howard Grubb. This instrument is mainly used for celestial photography, and has been engaged in (i) determining the distances of the stars; (ii) determining the distance of the sun by means of observations of the minor planet Eros; and (iii) measuring the proper motions of the stars in different parts of the sky. Recently a photo-electric photometer has been installed at the eye-end of the telescope, the object of which is the precise measurement of the variation of brightness of selected stars.
The Solar Physics Observatory stands on the Madingley Road, close to the older Observatory. It combines the former Astrophysical Department of the University Observatory and the Solar Physics Observatory, formerly at South Kensington, which was entrusted to the charge of Cambridge University in 1913.
The principal instruments are the following: (1) the Newall Telescope (aperture 25 inches) in the large dome; presented to the University in 1890, the gift of Mr. R. S. Newall, F.R.S., of Gateshead-on-Tyne, in whose private observatory it was erected about 1870 (it is devoted to spectrographic work); (2) the McClean solar instruments, comprising a double coelostat with mirrors 16 inches in diameter, an object glass having an aperture of 12 inches and a focal length of about 60 feet, and a spectrograph of the Littrow form; provided by the bequest of Mr. Frank McClean, F.R.S., and erected in buildings adjoining the Newall dome; (3) the Huggins Telescopes, which had been placed at the disposal of Sir William Huggins for many years by the Royal Society; they were presented in 1908 to the University by the Society and erected in a dome adjoining the astrophysical building; (4) a concave grating, mounted after Rowland's method, in the laboratory which was built in 1913 on the transference of the Solar Physics Observatory from South Kensington to Cambridge; (5) a spectroheliograph for the study of solar phenomena in monochromatic light, erected in the buildings to the south of the astrophysical building; and (6) a 36-inch reflector with a mirror (silver on glass) worked by Dr. Common, mounted equatorially in a dome to the south of the Newall dome.
The laboratory contains spectroscopic, photometric, and other apparatus for experimental research, and many photographic records of the spectra of both celestial and terrestrial sources of light.
A few years ago the works of the company occupied only 11,000 sq. ft. of floor area and employed fifty people. They now consist of five main buildings totalling 75,000 sq. ft. and give employment to approximately 900, while further extensions are being carried out or projected. The chief departments are as follows research department; machine shop, which includes model-making and tool-making sections; central material and component stores; component assembly, plating department; chassis assembly; coil-winding department; wiring, testing, and casing departments. There are in addition wood-polishing shops, a cabinet store, finished goods store, etc. The entire radio receiver chassis, with the exception of a few small component parts, is made and assembled in the works.
The Mill. - Sawston Paper Mill is mainly devoted to the manufacture of rag, tub-sized papers, but engine-sized rag and wood papers are also made. Rags cannot be mixed indiscriminately, and although they come into the mill from the rag-merchants under certain classifications, the final sorting must be left to the mill worker. Apart from the colour and condition of the rags, the fibre will differ in the various qualities, and considerable skill and experience is needed in sorting. The processes of cutting, boiling, and breaking-down to the "half-stuff" stage follow, and in the last stage, when the "half-stuff" goes to the beaters for reduction to pulp, fine adjustment of the beaters and careful judgment of the length of time required for beating are necessary in order to produce a high quality of fibre. The conversion of the pulp into paper follows, and reference may be made to the Paper read before the Institution by Messrs. W. W. Beaumont and L. N. Burt in 1926 for a description of modern paper-making machines. The final operations of cutting, sorting, packing, and baling demand the same care as all that has preceded them.
The Factory. - Sawston Factory is comparatively new and is of special interest, as the manufacture of pulp bottles and containers is not to be seen elsewhere. Wood pulp containers are made for edible products and are non-hygroscopic. They are also suitable for protecting glass, whilst specially impregnated they are being used for dry-cell batteries, etc. The plant used for their production involves the usual beating machines for reducing pulp boards to the pulp state, a series of vats through which the pulp passes until it reaches the moulding machines, and an air-compressing and superheating plant for drying and forcing the moisture out of the pulp. The pulp, a mixture of mechanical and sulphite wood, is kept in a state of constant agitation until it reaches the feed-pipe to the mould, into which it is forced. The excess water in the pulp drains off, and by means of compressed air at 70 lb. per sq. in. pressure and 750° F. temperature, the water still remaining in the pulp is blown out and the pulp itself practically dries. The regulation of the amount of pulp required for each bottle or box is a matter of mechanical adjustment on the machine; the opening of the mould and ejection of the article are also automatic. The container is given a final drying and then passes to the finishers, the inside being waxed where necessary. Every bottle or container is tested by hand for perfect fit of cap or lid, and any excess particles of pulp adhering to the edges are cleaned off. Paper pulp is also extensively used for a great variety of domestic and fancy goods. The process in use at Sawston differs from the old papier mache process, and the impregnation of the pulp takes place after the goods are made.
Another department of Sawston Factory is occupied in the manufacture of waxed paper, which, in consequence of the growth of the practice of wrapping foods, sweets, and bread, is now produced in enormous quantities. The web of paper to be waxed is fed between a steel and rubber-coated roller, which takes the wax from the trough and coats the paper as it passes through. Thence the paper passes over water-cooled drums and is rewound. Adjustment can be made to the machine for waxing one side of the paper only. As wrapping is now done mainly by machinery, a high degree of accuracy is demanded in the cutting, slitting and re-reeling processes which follow. Waxed wrappings for sweetmeats are slit and rewound into coils of a definite number of yards in length, the slitters on the machines being set to the necessary width. After threading its way through a series of smoothing rollers the reel of waxed paper passes over the rotary slitters to prepared cardboard spools on which it is rewound, the machine automatically stopping after the requisite length has been run off.
The manufacture of envelopes and toilet rolls is also carried on at Sawston. A large number of automatic envelope-making machines is employed, and these are each capable of turning out up to 8,000 commercial envelopes an hour.
The serious study of engineering at Cambridge may be said to have commenced in 1891, although prior to this date workshops existed and a limited amount of engineering instruction was provided. In that year Professor Ewing, now Sir Alfred Ewing, K.C.B., F.R.S., was appointed to be head of the Department of Engineering, and under his guidance and that of the late Professor Bertram Hopkinson, F.R.S. (1902-18), the Department grew steadily in numbers of students and in extent of buildings and equipment. After the War, when Professor Inglis was appointed to the Chair, the original premises in Free School Lane were no longer capable of further expansion, and steps were at once taken to commence the erection of new laboratories on the Scroope House site, which was acquired by the University for the purpose.
During the past ten years a gradual transference to the new site has been taking place, and now all the premises in Free School Lane have been vacated and the new laboratories, workshops. drawing office, and lecture rooms have been completed, with the exception of a portion of the front block. The whole school is, therefore, now self-contained on one site, and the Department of Aeronautics is also housed in Scroope House. The buildings of the Cambridge University Air Squadron have been erected in the adjacent grounds. The present number of students working in the Engineering Department is about 500.
Equipment. — In addition to a library containing the proceedings of the principal English engineering societies and the most important technical periodicals and books, the equipment of the new Engineering Laboratories includes:—
(1) In the Heat Engine Laboratory, two gas-engines (one fitted with a producer plant); five oil-engines (including a German submarine six-cylinder Diesel engine of 550 h.p., a 50 h.p. Diesel engine, and a 30 h.p. cold-starting engine); four petrol-engines (including a Ricardo variable-compression unit and a 360 h.p. Rolls-Royce aero-engine); steam-turbines (small de Laval and two Parsons); a Mirrlees steam-ejector; several steam-engines (including a Uniflow and a Robey compound); four refrigerating plants; and two small air-compressors. All the prime-movers are fitted either with brakes (of which two are Heenan and Froude water brakes) or direct-driven dynamos, and there are the usual measuring appliances, including exhaust calorimeters. Provision is also made for physico-chemical experiments, including the testing of oil fuels. In addition to the boilers required for warming the building, the Boiler-House contains two Babcock and Wilcox boilers with economizer, and one Cochran vertical boiler. One of the Babcock boilers is fitted with a chain-grate; the other two boilers are adapted for oil fuel, and three types of oil burner are represented. The boiler-house contains a steam-meter and automatic CO2 indicator.
(2) In the Structures and Testing of Materials Laboratory, seven testing machines, the largest of 50 tons capacity; a 150-ton hydraulic press; a strut tester; Brinell hardness testers; an Izod impact testing machine; and many special pieces of apparatus, such as alternating-stress machines; cement- and concrete-testing plant.
(3) In the Hydraulics Laboratory, two motor-driven centrifugal pumps delivering to an overhead tank of 20,000 gallons capacity, which supplies a turbine and Pelton wheel as well as the usual pipes, weirs and orifices, all fitted with suitable measuring apparatus; also a Pelton wheel for large head supplied direct from a centrifugal pump and motor, and a self-recording Venturimeter.
(4) In the Ferrous Metallurgical Laboratory, microscopes, photo-micrographic outfit, polishing and etching apparatus, electric furnaces, thermo-couple, radiation and resistance pyrometers as well as a thread recorder and other self-recording apparatus. A small chemical laboratory is equipped for the analysis of steel-works materials.
(5) In the Electrical Laboratory, a comprehensive equipment of direct, mono-, two-, and three-phase machines and motors, including rotary converters, transformers, synchronous and induction motors. There is a very full and complete outfit of measuring instruments.
(6) In the Wireless Laboratory, two aerials and an earth connexion are provided; and there is a quantity of measuring apparatus, condensers, inductances, and components for assembling transmitting and receiving arrangements of all kinds. Various direct-current and alternating-current supply voltages are available for thermionic work.
(7) In the workshops (which are now in process of transference from the old site in Free School Lane to the Scroope House site), the equipment comprises modern machine- and hand-tools for carpentry, pattern-making, turning, fitting and forging. A scientific-instrument makers' shop is also available, being chiefly used for maintenance work and the manufacture of research apparatus.
The operation of this factory is remarkable for the fact that it is confined to the months of October, November, and December, when the beetroots become available. No means of successfully storing them have yet been devised, so that the organization is faced with the difficult economic problem of operating its plant for only three months of the year. This difficulty is intensified by the necessity for a transport system capable of collecting and delivering at the factory two or three thousand tons of beets per day at a reasonable cost. These peculiar conditions are met by operating the plant at its greatest possible capacity night and day during the "campaign," as it is called, and spending the remainder of the year in so thorough an overhaul of the equipment that breakdown during operation is eliminated, as far as is humanly possible.
The boiler plant consists of thirteen Babcock boilers, eight of which supply saturated steam at 100 lb. per sq. in. gauge direct to the process mains, while the remainder supply the turbo-alternators with superheated steam at 160 lb. per sq. in. gauge. Wherever possible, condensate is conserved in the factory and returned to the feed-pump suction tank, and this supply is reinforced by condensed water vapour produced in the evaporating pans, so that there is no lack of distilled make-up water. The generating plant, which carries a maximum load of 1,000 kw., comprises three back-pressure turbo-alternators delivering their exhaust steam to the process mains of the factory at 15 lb. per sq. in. gauge pressure. There is also an auxiliary 50 kva. set driven by a 55 h.p. oil-engine which supplies the requirements of the factory during the non-productive period. A complete system of indicating signal lamps has been arranged to facilitate interchange of operating information, and in some departments distant centralized controls have been provided. These refinements are intended to minimize the smaller operating delays.
The process of beet sugar manufacture at this factory may now be summarized. On arrival at the factory the beets are unloaded into the silos and are conveyed by water through beet flumes to the pump which elevates them to the beet washer. They are then automatically weighed and fall into the cutting mills. The shredded beet, called "cossettes," is conveyed thence to the Steffen presses and the diffusion batteries, where juice is extracted. The pulp is dried and put into bags. After measurement the raw juice is mixed with quicklime, and carbon dioxide is then pumped through it to precipitate the impurities, which form insoluble compounds. These are extracted in filter presses, after which the juice is reheated and again carbonated and filtered to remove all the lime. The resulting "thin juice" then passes through bag filters and sulphitation tanks for the further removal of impurities, after which it goes to the evaporators where the water is evaporated and the "thin juice" changed into "thick juice." The latter passes into the vacuum or boiling press where it is boiled down to a "massecuite" (i.e. crystallization). The massecuite then falls into the crystallizers, and the sugar is finally separated in the centrifugals, after which it is conveyed to the granulator, the sugar bins, and the bagging machine.
At the end of the War the Royal Air Force had a very large number of aircraft and aero-engines, the output of the country having attained its maximum just at the cessation of hostilities.
Under war conditions more stress had necessarily to be laid on the production of new material than on the repair of that which was partly worn; but in order to economize the resources available as far as possible, repair units were set up as close to the theatre of operations as they could be effectively maintained, where repairs could be effected or aircraft, wrecked beyond repair, could be overhauled for the salvage of such spare parts as could be obtained from them. In the reconstruction period after 1919, only one of these units survived at home, namely the Home Aircraft Depot; and in the Air Force Commands overseas (in India, Iraq and Egypt) repair work was made to form a part of the functions of each of the main store depots from which the areas are supplied.
The Home Aircraft Depot is therefore the only unit at home of its kind in the Royal Air Force entirely devoted to the reconditioning of aircraft and their engines. From this special function it has naturally become the centre at which the skilled aircraft riggers and fitters of the Service receive final training before being drafted to work in the depots overseas. In order that this shall be done a certain proportion of the repairs and overhauls necessarily arising from the use of aircraft by squadrons at home is diverted from its normal route back to the manufacturer's works and taken to Henlow; so that the airmen there are enabled to perform actual useful work on the same kinds of aircraft and engines as they would have to deal with in time of war.
These men come from the School of Technical Training at Halton in Buckinghamshire with some theoretical knowledge and a certain amount of skill of hand, but at Henlow they learn confidence in their own capacity under the conditions required by a regular flow of output. They do not acquire this skill, however, under the conditions of a modern factory; for the essential feature of Henlow is to impart the skill necessary for maintaining aircraft and aero-engines under the conditions obtaining in overseas commands or on active service. Moreover, there is no opportunity for introducing mass-production methods, because of the variety of the damage which has been sustained by the machines and engines returned for overhaul. Every craftsman has therefore to develop the highest degree of practical skill of which he is capable he may be called upon to carry out an important piece of work in a repair depot or out in the desert. Whatever the conditions may be, the Service demands that the damage should be repaired as rapidly and systematically as possible so as to enable the machine to return to the fighting strength of t)ie squadron.
The Depot is organized with a Headquarters, to which are attached a stores section and an accounting section. The stores section not only supplies the new parts required to make up deficiencies observed in overhauling machines and engines, but also has a large storage section in which the material awaiting overhaul or repair is stored until it can be allotted to the appropriate workshop. The actual workshops are controlled by the Central Technical Office, which is not only responsible for the actual work carried out, but sees that any improvements which have recently been incorporated in the design of a machine or engine are also embodied in those which are passing through the Depot. This office also reports on all defects of importance, so that the technical departments of the Air Ministry and the manufacturers may be made aware of improvements which in practice are found to be necessary.
Acting under the Central Technical Office are two Repair Sections, one for aeroplanes and one for engines. At the present time the following aircraft will be found at the Depot; De Havilland Moth; Vickers Vimy; Armstrong-Whitworth Atlas; Armstrong-Whitworth Siskin; Bristol Bulldog; Fairey IIIF (general purpose); and Westland Wapiti. The following engines will be seen undergoing repair: Armstrong-Siddeley Jaguar; Lynx and Mongoose; Napier Lion; and Bristol Jupiter. Each of these engines has several "marks" or varieties in the general series; thus there will be observed the Jaguar IV, IV*, IVC, supercharged, and IVC supercharged. The complexity of work in these two sections may be judged by the number of different trades which are employed: carpenters, clerks, coach painters, coppersmiths and metal workers, metal riggers, electricians, fabric workers, fitters (aero), fitters (armourer), and storekeepers.
Parallel with the other repair sections under the Central Technical Office is a General Engineering Section, which is employed on repair of the many accessory items of equipment which go to make up the modern fighting aeroplane. The armament repair shop deals with machine-guns, ammunition drums, bomb racks, bomb sights, Scarf rings and other weapons employed in the aircraft. The photographic repair shop deals with the highly sensitive cameras which are used for reconnaissance from great heights; the wireless repair shop with the delicate instruments required for wireless telegraphy and telephony, both from aircraft to their ground headquarters and to one another; the instrument repair shop with the air-speed indicators and other instruments provided for the pilot's guidance in flying his machine, as well as sparking-plugs, magnetos and the ignition systems of aero-engines. There is also a foundry and blacksmith's shop, and a metal component shop for dealing with parts of the aircraft which need moulding or welding, such as radiators, tanks, water- pumps and other components of the aircraft. The M/T repair shops undertake a small quantity of various repairs to motor transport specifically for giving a sufficient number of craftsmen a technical insight into the various types of vehicle employed overseas in the Royal Air Force.
An interesting part of the Depot is the Parachute Shop, which is the centre of all parachute work in the Royal Air Force. It will be remembered that parachutes were introduced into the Service about five years ago, and have been instrumental in saving a number of lives in cases where the aircraft would otherwise have crashed to the ground out of control with its occupants on board. Here new types of parachutes are tested with weighted dummies, and parachutes of the type which is at present standard in the Royal Air Force are similarly tested individually before they are issued to the Service. A certain amount of instructional work is also carried out here so that officers and men of the squadrons may be fully conversant with the maintenance of the parachute to which at some time or another they may be obliged to trust their lives.
Henlow is also the home of the Officers' Engineering Course, at which those officers of the Royal Air Force who specialize in aeronautical engineering are trained. About thirty officers take the course each year, and stay for two years: every one of them has had four years of practical flying in squadrons before he commences the course. At its termination, a few of the most able students proceed for two or sometimes three years further study at Cambridge or London University; but the majority are appointed for specialist engineering duties with squadrons and other units of the Service.
It will be recollected that it was announced in the Annual Report for 1930 that an arrangement has been concluded for the award of a National Diploma (Air) in Mechanical Engineering by the Institution in conjunction with the Board of Education and the Air Ministry to officers of the Royal Air Force who successfully pass through this course at Henlow and the examination at its conclusion. The work of the Course is subject to review by representatives of the Institution and the Board, and the final examination is assessed on behalf of the Institution in the same manner as the examinations held in civilian technical colleges and schools. The instructional workshops and laboratories used by these student officers, which are quite distinct from the workshops of the Repair Depot, will be open to view.
The activities of the Depot are at the moment (June 1931) under reorganization, and certain parts of it are still in process of formation. Visitors will therefore unfortunately not be able at the present time to see in operation the whole of the system which has been described above.
These works are laid out to manufacture 60,000 tons of Portland cement per year, but they have been designed and built in such a way that the output can be trebled at comparatively small extra cost. The cement is manufactured from clay and limestone available in quarries situated on the company's property. Until sufficient clay has been removed the limestone will be obtained from the dumps of stone deposited during the quarrying operations of the last 800 years. These dumps contain about three million tons of limestone, and as no explosives are required it is obtainable very economically. As the estate contains both high silicious and high aluminous clay the slurry is corrected exactly to what is required.
The slurry mixing operation is carried out by the usual mechanical mixer, but in addition the slurry is at intervals aerated by means of a compressed-air installation, thus securing very thorough mixing. The whole of the plant is of modern design and was actually erected in less than twelve months.
The factory consists of a machine shop, fitting shop, sub-assembly, and final assembly departments, and printing department, and is devoted to the manufacture of electrical tabulating and sorting machines and the printing of the necessary cards for use with them.
Letchworth is the first material outcome of the labours of the late Sir Ebenezer Howard. Observing the tendency of many of the older and the modern towns to become developed, even at the point of congestion, with industrial and commercial buildings, while they drew from outlying districts large populations for whom they were unable to provide healthy conditions of life, Sir Ebenezer Howard suggested a means by which this process may be checked and towns of the old type replaced by towns of the new type. Such new towns were not to be suburban annexes to old ones, but towns complete in themselves and planned for industry and healthy living, of a size that makes possible a full measure of social life, and surrounded by a permanent belt of rural land.
The company entitled "First Garden City" was formed in 1903 and acquired the land, about 4,600 acres in extent, on which the present town stands. The whole town is divided into areas for specific types of development; land near the railway is reserved for factories; the centre of the town is reserved for shops and public buildings, while a little removed from these two areas are the residential zones.
The features of the estate were very carefully surveyed by Dr. Raymond Unwin and Mr. Barry Parker in 1904, and the different areas, subsequently allocated for specific purposes, were all decided upon after consideration of their essential needs. The many attractive features such as the Norton Common, the valley now occupied by Howard Park, the villages of Norton and Willian, and the green spinneys and belts of trees have all been reserved and incorporated in the general plan of the town. A definite part of the plan for the development of Letchworth is the provision of a civic centre. The Town Square, now surrounded by tall poplar trees and laid out with flower gardens and lawns, will eventually have fronting it the chief public buildings of the town. The rural aspect of the older roads has been carefully preserved, and the aboriginal oaks, elms, and ash groves were brought into the scheme of road direction. The new roads have been planted with trees in suitable variety, thus imparting to each road a special character of its own.
To the north-east of the town is to be found the industrial area. The prevailing wind coming from the south-west, the little smoke that is necessarily produced is blown away from the residential area. Surrounding the whole town is a belt of open land, which has been reserved for all time for its present use. This acts as protection against overgrowth from without or within, and ensures that the countryside shall be always within walking distance of the centre of the town. The company have provided and administer the water, gas, and electricity undertakings, and, before the creation of the Urban District Council, roads and sewerage; the latter are now under the control of the Council. With new development the company construct the roads and sewers to the Urban District Council's specifications and they are taken over by the Council for maintenance under the Private Street Works Acts.
Waterworks. - The construction of the waterworks was begun in 1904. The site of the pumping station was fixed in relation to the surface lie of the land and the main valleys. Water runs off the neighbouring Chilterns into the underground chalk, giving an ideal condition for purity of water supply. The quantity of water pumped in 1930 was 273 million gallons. Excellent reservoirs have been constructed, completely roofed in with reinforced concrete, supported upon brick partition walls, on the Weston Hills; these enable a good water pressure to be given over the whole area. The plant installed in the water-pumping station consists of electric motors driving Ashley bore-hole and high-service reciprocating pumps; gas-engines driving similar plants; and electrically driven vertical centrifugal plant. The largest unit requires 200 h.p., and pumps 60,000 gallons per hour.
Gas Undertaking. — The erection of a gasworks was commenced by the company in 1905. An increase in consumption has been reported each year, and extensions and new holders have been erected as demands have increased. The total holder capacity is 450,000 cu. ft. In 1930 over 130,000,000 cu. ft. were used.
Electricity. — Electricity was first supplied in Letchworth in 1907, and at the present time not only is the whole town supplied, but in addition, by special order, the company supplies Baldock, Biggleswade, Stotfold and Arlesey, and a number of villages also. The total population served by the company is over 33,000 and the area nearly 25,000 acres. There are now 3,200 consumers connected to the company's mains. The generating plant has been extended as required and the total capacity of the station is now 10,000 kw.
The main output of this factory is devoted to the measurement and automatic control of temperature by electrical means. The instruments to be seen in the course of construction include the electrical resistance thermometer for low temperatures, the thermo-electric pyrometer for medium temperatures, and the optical and radiation types for the highest attainable temperatures. The types of apparatus made for temperature measurement include some for laboratory and research work, but are mainly for industrial use. The combination of robustness, to withstand rough usage in service, with intrinsic delicacy has been made possible by the incorporation of a special system of spring mounting of the moving coil whereby the necessarily delicate pivot points are shielded from damage in service.
Interesting developments have taken place in recent years in systems of automatic control of temperature for furnaces heated by electricity, gas, or oil and for apparatus heated by the secondary means of steam or hot water. Although hand control would appear to have the power of anticipation, while an automatic system cannot anticipate but can only deal with the state of affairs at any given instant, yet it is the universal experience that temperatures controlled by automatic systems are more regular than can be achieved with hand control. Other apparatus of technical interest includes a Duplex electrical aero-engine speed indicator, in which the speeds of two engines are directly contrasted, thus greatly assisting the pilot; and the "Introscope," an optical apparatus for the internal examination of tubes, bores, and other engineering enclosures. The present year marks the "coming of age" of the business.
Some of the first motor-cabs to appear on the streets of London were made at the firm's original works at Bassingbourn, established in 1900. Later the company built the first factory at Letchworth, called Gresham Iron Works, where they have carried on the manufacture of railway materials, especially the component parts of the continuous automatic vacuum brake, and industrial oil-engines. These works have been almost continuously extended since the firm transferred its activities to them, with the exception of the War period.
The present establishment contains a commodious iron foundry equipped with modern moulding and handling machinery, and has attached to it a pattern shop and pattern store. In the plating shop, chambers and reservoirs of all descriptions, both welded and riveted, are manufactured, and batteries of drop-hammers turn out drop-forgings not only for use in the firm's own products, but for dispatch to customers elsewhere. This shop also contains presses, hydraulically and power operated, from quite a small size to the largest power press built in this country, and a still larger double-acting hydraulic press which is capable of making, from a steel blank, a solid-drawn article of a greater depth than can be obtained anywhere else in the British Isles.
The die-sinking shop is equipped for sinking the tools required on the drop-hammers and the smallest presses, but tools for the larger presses are made in the machine shop. This machine shop carries on the manufacture of petrol paraffin engines in sizes from 2 to 28 b.h.p. The engines are used for electric-lighting and water-pumping sets, and for driving air-exhausters, etc. The air-exhausters manufactured have been specially developed for reliable service under railway conditions.
Vacuum brake cylinders, made throughout from wrought steel, are manufactured, and cylinders, engines, exhausters, and other equipment are fully tested in the various testing departments before dispatch. The original offices are used for storage purposes and the present offices are lit by an electric lighting set driven by one of the firm's oil-engines.
This factory, which was erected and equipped during the War, is situated in the reserved factory area of Letchworth Garden City and covers about 27 acres, of which about 6 acres are under roof. During the War the works employed about 3,000 Belgian refugees on the manufacture of munitions. They are now under British management and employ about 700 work-people, all of whom are British.
The works consist of a large steel foundry and an up-to-date engineering shop. The steel foundry is engaged upon the production of steel castings varying from a few pounds up to 5 tons in weight. They include general engineering steel castings, railway rolling-stock castings such as locomotive and wagon wheel centres, axle-boxes, etc., marine castings such as ships' davit arms and frames (which form one of the firm's specialities), motor lorry castings, crane castings, etc. The foundry building is made up of two bays under one roof 730 feet by about 150 feet and has a handling equipment of two 15-ton and seven 5-ton overhead electric cranes.
The melting plant consists of four surface-blown steel converters fed by two cupolas of 6 tons per hour capacity each. The converters themselves have a capacity of about 2.5 tons each. There is also one basic-lined electric furnace of 30 cwt. capacity. The equipment also includes annealing ovens and mould- and core-drying furnaces, all of which are equipped with thermo-electric pyrometers. There are numerous moulding machines either of the hand-operated or compressed-air types, and there is also a sand Slinger.
The sand-mixing plant is entirely automatic and built on the gravity principle. Castings are cleaned by shot blasting and both electric and oxy-acetylene plants are installed for cutting off risers, welding, etc. The firm has also recently installed an oxygen producing plant based on the principle of the fractional distillation of liquid air, which is producing regularly 100,000 cu. ft. of oxygen of high purity per week.
The output capacity of the foundry on the basis of full-time working is about 600 to 700 tons of steel castings per month on a day shift only. An up-to-date chemical and metallographical laboratory controls the composition of the raw materials and liquid steel and the structure of the castings after heat-treatment.
The extensive machine shop covers a total area of 385 feet by 188 feet and is equipped with some 300 modern machine-tools. One large bay of the shop served by two 5-ton overhead electric cranes is devoted to the machining of castings from the foundry and to the erecting of crude-oil engines, the firm having recently taken over the connexion of the Campbell Gas Engine Company of Halifax. These engines range from 10 h.p. to 72 h.p. for the single-cylinder types, are produced at the rate of about three per week and are shipped to all parts of the world. There is also an extensive trade in spare parts for all existing Campbell engines. Attached to the machine shops is a physical testing department, a well-equipped tool room, and heat-treatment department.
The remaining buildings are occupied as assembly shops, general stores, etc., and on a site close to the factory the company have erected a large canteen capable of catering for the needs of their employees.
The Marmet patent was taken out by the inventor and present managing director, Mr. E. T. Morriss, in 1912. In 1913 a private limited liability company was formed, and it became a public company in 1924. The factories are situated in Letchworth, one in Works Road and the other or main factory, which is a modern reinforced concrete building, in Icknield Way.
The Works Road factory comprises timber sheds, saw-mill, and woodworking shop, and manufactures all the parts for the perambulator bodies, which are then conveyed by lorry to the main factory for assembly. The manufacture of furniture was started some two years ago and is carried out throughout at the Works Road factory.
The main factory is in the form of a hollow square. The perambulator bodies are assembled in the carpenters' shop, then proceed to the paint shop, which is equipped with up-to-date spray- painting outfits using both oil paints and cellulose, and finally through the varnish and drying rooms. They are then upholstered, and supplied with the necessary parts from the hood-making, apron-making, and machine departments, which are equipped with batteries of power-driven sewing machines, finally passing to the fitting-up department. The manufacture of the chassis is carried out in the tool room and the machine shop. All enamelling, nickel-plating, chromium-plating, copper-plating, etc., are done on the premises. There is a modern rim-making plant consisting of rolling, cutting, and electric welding machines, automatic punches, etc.
Besides the manufacture of baby carriages, doll prams, and folding baby carriages, invalid chairs and cyclettes are also produced.
There was no other low-loading road vehicle on the market at the time the firm commenced production in 1922 of the pioneer "S D Freighter," but it was followed by such success that vehicles of this type are now extensively used for municipal refuse collection, the conveyance of cable-drums, and aerodrome work. The works have been extended every year, and now cover a large area, with a block of offices facing south. The ground floor of the latter is mainly occupied by the workmen's dining-room and cloak-room. There is direct access from the offices to the works, of which the main part is laid out in seven well-lighted bays. The latest extension, a separate building at the west end of the works, has three large bays, and houses the paint shop and chassis-testing and body-building departments. Of the main building, three bays constitute the machine shop, while other sections form the fitting and erecting shops; engine-building shop; engine test, hardening, and tool rooms; tool, rough, and finished stores; and view room.
The Air Ministry have placed contracts with the firm for certain special designs and experimental work, of which an interesting example is a special motor-driven unit for handling large aeroplanes on the ground. The employees of the firm are paid more than the Trade Union rate for the district, and more than 50 per cent of the shareholders are employees. The company and the vehicles which it produces are entirely British as to capital, labour and materials, and 85 per cent of the adult employees are ex-servicemen.
The Spirella Factory, devoted to the manufacture of corsets and lingerie, is of special interest on account of its ideal conditions and the attention that has been paid to the welfare of the employees, of whom nine-tenths are women. Almost one-half the present employees count over ten years of service with the company. The factory covers a floor space of 3 acres and is a beautiful building set in sylvan surroundings. Every work-bench is so placed that the operator may enjoy the maximum proportion of direct sunlight. A break of fifteen minutes is made in mid-morning and mid-afternoon for rest and refreshment. The company sells its products through the medium of resident corsetieres, who attend a permanent training school attached to the factory, and there is also a commercial college where the office employees are thoroughly trained in commercial subjects, classes being conducted during business hours and the cost being borne by the company. The well-equipped library is an outstanding feature of the welfare provision afforded in this ideal factory.
Since its foundation the business of shoe-making has undergone revolutionary changes. Most of the processes were originally carried out by hand in the men's own homes. It is only in comparatively recent years that machine processes have been developed, making possible mass-production in commodious buildings. The business was founded in 1826 and the company of Lotus was incorporated in 1919. It operates factories in Stafford, Stone, and Northampton which were founded by the forefathers of the present directors. The factory at Northampton is devoted to the manufacture of men's shoes. There are six main departments: (1) "Clicking," where the uppers are cut from skins, mostly of calf and kid; (2) "Closing," where the parts of the upper are stitched together; (3) "Bottom stuff," in which soles, insoles, stiffeners, etc., are cut and prepared in various ways; (4) "Making," in which, as the name implies, the shoes are actually made; (5) "Finishing," in which the rough leather of the soles is finished; and (6) "Treeing," in which the uppers of the shoes are cleaned, ironed, and dressed. The machinery in all the departments is run by electric power, with two or more motors in each room. There is a tendency to incorporate separate motors in individual machines, and where this is economical the method is adopted.
The company's speciality is the manufacture of in-stock shoes which are distributed to the public through agents, this system giving better service to retailers than making shoes to order. With a commodity as multifarious as footwear a highly efficient stock system is not easy to run. Taking into account different styles, shapes, fittings and sizes, some 10,000 to 15,000 varieties of product have to be made and stocked. In addition to its home trade the company exports a considerable portion of its products, but this business is becoming increasingly difficult owing to the general raising of tariffs. Gymnasia and extensive sports grounds are provided for the welfare of the 2,000 to 3,000 work-people.
At this factory the five main divisions of shoe manufacturing, namely "Clicking," "Closing," "Rough Stuff," "Making," and "Finishing," which have preserved their identity for at least a century, are observed. In "Clicking," or cutting out the sections of an upper, careful selection of the portion of skin is made, the butts being used for the best quality and the most important wearing parts of the shoe, and shoulders and flanks for less important parts or cheaper goods. Defects of growth, flaying, and branding, need to be avoided, and the picked parts arranged best for wear and matching. In the "Closing" operations the best English shoes still retain the fitting processes, i.e. the sticking together of certain principal parts before permanently sewing them, which is done on fitting blocks. A flattened-out upper without this preparation would require forced shaping in subsequent machinery operations, and would revert to unshapeliness in course of wear. Sewing machines similar to the ordinary domestic machine, except that they are run by power and with a guiding wheel, are employed. Some of the sewing machines have a curved or cylindrical bed and others have a knife attachment which trims the lining to the shape of the outside part while stitching both together. All edges are first "skived" and then turned, beaded or bound. There are automatic machines for the making of button holes and the fixing of buttons and eyelets.
The "Rough Stuff," or foundations of the shoe, are stamped out with power presses and the same procedure of "skiving" edges, moulding and preparing for the making up is observed as in the upper closing operations. A grading machine "feels" for the thinnest part of soles of uneven thickness and reduces the whole to that standard, marking the key number of the substance arrived at on the sole, and passing it on in a moment. The sole leather is stored and sorted to order.
There are four distinct methods of "Making": (1) hand-sewn, (2) machine welted, (3) machine sewn, and (4) "turnshoe" method. The first follows the procedure handed down and perfected from generation to generation, and in the second machines have been invented which very nearly approach the hand operations, so that the last remains in the shoe throughout all the process of making and finishing. The "machine sewn" method at its inception completely revolutionized previous ideas of shoe-making, and in its modern form is indispensable for producing lightweight shoes economically and quickly. It differs from the welted method in that the upper is attached first to the insole by permanent tacks instead of sewing, and as there is no welt, the stitches that hold the shoe pass straight through the upper and insole. It is necessary to clench these fine lasting tacks, so the bottom of the wooden last has an iron plate. The "turnshoe" method produces the shoes known as "pumps," which are made inside out, "lasted" with the linings outside and after sewing are turned carefully while wet. "Heeling" is common to each of the four processes and is done by machines embodying a power hammer faced with long driving pins. "Louis" heels, however, demand quite another set of operations, and Messrs. Manfield were the first to install a complete Louis heeling plant.
In the "Finishing" department the foreparts and heels are pared round the edges with knives and the edges are then coloured and set by hot pulsating irons. Rotary machines burnish the heel and sole, which have been previously coloured. In the stock room over 1,000 varieties of boots and shoes are stocked; each variety may be kept in three or even four fittings, or widths, and in every width there are thirteen sizes or half-sizes. The rises and falls of this reservoir of stock are being constantly noted by the directorate, and calculations bearing on material, plant, machinery, and labour revised accordingly.
The welfare of the employees is looked after by a fully qualified welfare supervisor and a voluntary elective committee. H.R.H. The Duke of York paid a surprise visit to the factory recently and was especially interested in the welfare work of the firm, which extends beyond the provision of a spacious recreation room and the distribution of cups of tea to the departments every afternoon, since workers overtaken by illness are visited at their homes and assisted in various ways where necessary.
The present installed capacity of the generating station is 31,500 kw. Current is generated at 6,600 volts at a frequency of 50 cycles per second. The maximum half-hour load during 1930 was 17,740 kw. and the thermal efficiency of the station for that year 18.72 per cent. The coal, consisting mainly of Warwickshire and Leicestershire fine slacks of about 9,020 B.Th.U. gross calorific value, is dealt with in the private siding by an electric battery locomotive and thence by bucket-type elevators and pusher-plate and drag-link conveyers capable of handling 60 tons per hour.
The steam-raising plant comprises ten water-tube boilers of Babcock and Wilcox and Stirling types, with a total normal evaporative capacity of 336,200 lb. per hour. Mechanical travelling and chain-grate stokers are fitted throughout. The latest extension consists of two five-drum Stirling boilers, with a normal duty of 60,000 lb. per hour; each unit is fitted with Underfeed "L" type grates and [Howden|Howden Ljungstrom]] air-heaters, no economizer being fitted. The forced-draught and induced-draught fans are housed above the boiler, making a very compact arrangement. Access to the fan chamber and boiler tops is obtained by means of an electric lift. The gases from the boilers discharge into a common short steel stack. When supplied with feed-water at 150° F., the efficiency of each unit is 86 per cent, the steam conditions being 220 lb. per sq. in. pressure and 750° F. total temperature.
The make-up water is obtained from the river. The initial hardness of 20 degrees is reduced to about 4 degrees by means of lime and soda in a Kennicott softening plant with an output of 10,000 lb. per hour. The treated water is fed into a Vickers "Controflo" evaporator and the distillate from this constitutes the "make-up," thus ensuring and maintaining pure boiler feed. The boiler feed-pumps, six in number, are housed in two separate rooms and are steam-turbine driven, the heat in the exhaust steam being recovered in direct-contact feed-heaters through which the main turbine condensate passes.
The ash is removed from the ash hoppers, and by means of bogies is conveyed to an automatic ash hoist which feeds a concrete storage hopper. The ashes can be taken from this hopper by railway wagon or by lorry.
The main turbine room contains six turbo-generators, the largest of which is a two-cylinder machine of 12,500 kw. maximum continuous rating. The steam is delivered to the turbine room at 200 lb. per sq. in. and 725° F. One of the earlier machines of 6,000 kw. capacity is fitted with a de-superheater capable of reducing the temperature of 75,000 lb. of steam per hour from 725° F. to 625° F. The auxiliary plant of each set consists of circulating- water pumps, water-extraction pumps and air-pumps all in duplicate. Alternating-current low-tension motor drives are employed with alternative direct-current motor drives for emergency use. The circulating water is obtained from the river Nene, and two cooling towers with a combined capacity of 864,000 gallons per hour are provided for emergency use. The water is continuously treated with a Patersons chlorine plant, ensuring freedom from condenser and pipe-work fouling. Distance indicating thermometers are provided on the condensing plant and on the alternators for easy observations of conditions. Closed-circuit air-cooling is employed in the later machines, the ventilating fans in all cases being mounted on the main alternator shafts.
Voltage is controlled by a Metropolitan-Vickers Tirrel type regulator which can be used in conjunction with any alternator. The 6,600 volt switch-gear is housed in stone-work cubicles, and duplicate bus-bars are provided, the bus-bar chamber and switch chambers being on separate floors. 11,000 volt bus-bars and 33,000 volt bus-bars are installed to supply various feeders at these voltages through step-up transformers, one of which, for 33,000 volts, is fitted with a choke coil for power-factor correction on light loads. The extra high-tension switch-gear is of the metal-clad type and is remote controlled, batteries being provided for the closing and tripping circuits.
The works supply switchboards are fed by 6,600 volt to 420 volt step-down transformers, the auxiliaries being, in the main, alternating-current driven, with direct-current standby provided by batteries and a works rotary converter.
Northampton has been for centuries the centre of the boot-making industry, and is known all the world over for the high quality of its productions. In the early days the Cordwainer or Cobbler used to carry on his craft in his own home. Towards the end of the last century, machinery was introduced and the transference of the work from the home to the factory was begun. The "True-form" business was established about the time this revolution in the trade was taking place, forty years ago, in a small factory capable of an output of only a few hundred pairs per week. The factory at that time was merely a centre for assembling and distributing the parts of the shoes amongst the workers, and a store-house for the finished article. Some years later a new site was acquired, and a more modern factory built.
In 1912 the present company was formed, which now operates two of the largest boot factories in the country. These buildings are situated in the most healthy part of the town, covering a large area of ground and containing spacious well-lighted, well-warmed, and well-ventilated rooms. The larger factory in Stimpson Avenue is devoted to the production of men's boots and shoes, and has an output of 24,000 pairs per week; in the other factory situate in Barry Road only ladies' shoes are made, the capacity being 12,000 pairs per week. The number of employees in the two factories is 2,000.
Power is derived from the supply of the Northampton Electric Light and Power Company. The machines in the men's factory are driven by thirty-six electric motors of a total of 328 h.p., and those in the ladies' factory by seventeen motors of a total of 180 h.p. Dust-extracton plants are fitted, working with a cyclone for the removal of fine particles of leather and dust occasioned by the various operations.
The company has its own retail branches situate in all large towns in the British Isles. The retail price of all goods is stamped on the sole in the factories and the shoes are stored in the adjoining warehouse, which is capable of accommodating half-a-million pairs. The distribution to the retail branches is made weekly, road transport being chiefly employed.
In 1927, soon after the completion of a new wing to the men's factory, H.R.H. The Prince of Wales visited Northampton and was conducted over the completed works. In 1922, the company purchased ground which has been converted into playing fields for various sports for the use of the employees.
The company was formed in 1909 to continue the business formerly carried on by Messrs. Archibald Smith and Stevens. The records of the latter go back to 1760, when a general engineering business was transacted in a small works located on the site of the Prince of Wales Theatre, Leicester Square, London. Very early in the nineteenth century the manufacture of the "Janus" door spring was commenced, and subsequently the manufacture of wire-cable stranding machines was taken up, and among the machines produced were some that were used for making the first Atlantic cable.
About this period new and larger works were built at Battersea, London, and the activities of the firm began to be concentrated on the making of lifts. In the early days these were operated by hand or belt power, or hydraulically. A certain number of steam-driven lifts have been produced, but their application is strictly limited for obvious reasons. Later, in the "nineties," when the use of electricity was developing, this form of power was investigated, and to-day it has practically supplanted all other means of driving lifts.
In 1910 the company moved to Northampton where Abbey Works was built, doubling the previous output capacity of the Battersea shops. The latter were retained to deal with London maintenance service and repairs. Abbey Works as built originally consisted of seven bays, each 30 feet wide by 160 feet long, with a separate two-story office building 90 feet by 30 feet. In 1918 two of the bays were lengthened by an additional 220 feet to deal with munitions requirements. The manufacture of all types of lifts is carried out completely, except for the castings and electric motors, and it will be of interest to mention that, except for one ship, all H.M. "Dreadnoughts" and "Super-Dreadnoughts" were equipped with lifts by the company, totalling upwards of 200 in number.
At the latter end of last year the company amalgamated with The Express Lift Company (General Electric Company) of Westminster and elsewhere. It is proposed to manufacture the whole of the requirements of the combined company at Abbey Works, and a large extension of the factory is practically completed for this purpose.
The whole trend of lift design in this country has been revolutionized during the last four or five years, due to the demand for higher speeds, extreme accuracy of stop at floor levels, more complete automatic operation, and the standardization of alternating-current. The company has taken its share in the design and development of the requisite control gear. It produced the first all-British design of "gearless" lift, and with its associated company is now engaged in the manufacture of the first all-British moving stairway. The latest form of lift control-gear employs the thermionic valve to achieve greater silence in operation.
Abbey Works is noteworthy for the flexibility of its arrangement of shafting, etc., which permits a rearrangement of departments to be made with the maximum of ease and without waste of material. Attention is also directed to one or two machine-tools of special design, namely a worm-wheel generator, a guide drilling machine, etc.
The firm was founded in 1915 and employs about fifty people. The products are mostly machine-tools for special purposes, chiefly in connexion with precision grinding and profile milling. The firm has recently specialized in automatic thread-grinding machines, in which considerable interest is being taken.
The work of Jacob Perkins, so well known to engineers as the inventor of a high-pressure boiler in the early days of the nineteenth century, was the origination of this firm, which was established in 1819 under the style of A. M. Perkins and Son. Operating from London, it established a large connexion in small-bore heating installations, and was responsible for notable developments in high- pressure steam-boilers and engines, among which not the least interesting are " Uniflow " cylinders and the use of pressures of up to 1,000 lb. per sq. in. By successive steps of absorption or amalgamation, the company now comprises (in addition to A. M. Perkins and Son) Werner and Pfleiderer, London; Joseph Baker and Sons, Willesden; Lewis and Pointon Panification of Wellington; and David Thomson of Edinburgh; and has important financial and technical associations with large works in Germany, France, U.S.A., Canada and Australia.
The company specialize in the manufacture of food-producing machinery (especially for bread, biscuit, confectionery, chocolate and sugar manufacture), and laundry, soap, rubber and artificial silk machinery. Some of the machines for these purposes are, by modification, capable of wider use in the chemical and allied industries.
The English Works normally employ some 2,500 people, and are up-to-date. At the Peterborough Works are a pattern shop and foundry (for iron, alloy steel, brass, and aluminium castings), a plate shop, containing an extensive electric and acetylene welding section, machine and erection shops, tool room and stores. The various bays are served by electric cranes, and the lay-out is on modern lines. Separate experimental departments exist for research and development work.
Queen Street Ironworks were founded about 1830 in their present location, within five minutes' walk of Peterborough Cathedral. Although now known best for the manufacture of motor road-rollers, the works still construct steam-cooking apparatus almost identical with that made at the inception of the firm, and exhibited in the first Great International Exhibition at Paris in 1867. About 1850 Mr. William Barford joined the firm, and in 1860 Mr. Thomas Perkins became a partner. One of their first joint enterprises was a patent taken out in 1862 for grass and road rollers so constructed that the weight could be increased by filling them with water.
In the "Seventies" and early "Eighties," the "Roundabout" method of steam cultivation developed by the firm helped to build up its reputation. About 1884 the manufacture of small, vertical steam-engines with cross-tube boilers was undertaken, and in 1887 self-propelled steam-rollers were made. In 1904 a new era was inaugurated by the design and manufacture of the first internal-combustion engined road-roller. The motive power was a single- cylinder Simms engine of 8 h.p., and this roller was exhibited at the Royal Show in 1905. The firm has also made a speciality of home and hand rollers for upwards of seventy years.
The major activity in the works is now the construction of motor road-rollers (petrol, paraffin, and high-speed Diesel) of from 1 to 17 ton, for road construction work. The works are laid out with specialized machinery for their production, and are well equipped with machine-tools, electric welding plant, and oxy-acetylene cutting machines. The foundry supplies all grey-iron castings required without recourse to outside concerns. Electric drives are used throughout and both alternating- and direct-current is used.
Another section of the works is devoted to the construction of cooking plant, and in addition carries out extensive contracts for heating and ventilating large buildings. Allied to this branch of engineering is a section producing dairy equipment, which has been largely instrumental in the introduction of cleaner methods and more sanitary equipment, of both large and small dairies, during the last few years. This work was commenced in 1923, and since then the firm has equipped over 3,000 dairies. The average number of employees is about 500, and their social welfare is well looked after by a sports and social committee as well as by a Works Council.
The firm was founded by the late Mr. Peter Brotherhood in 1867, and formerly occupied works on Thames-side on the site of the new County Hall. The name first came into prominence by the invention of the Brotherhood three-cylinder radial engine, which was widely used during the period 1878 to about 1895 for driving directly the dynamos fitted for the lighting of warships, fans for forced draught, circulating pumps, etc. Engines of this type were also used for the propulsion of the earliest Whitehead torpedoes, and are still, in a four-cylinder form, universally used for this purpose. Compressors for the high-pressure air for the torpedo service of most of the navies of the world were, and still are, one of the firm's chief specialities.
In 1907 the firm moved to its present site, extending to about 16 acres. The various workshops occupy a covered space of about 8 acres. The iron foundry is a separate building with a floor area of 34,000 sq. ft., to which the fuel and pig-iron are brought direct by means of a railway siding. The cupolas are capable of producing castings up to about 18 tons in weight, and all castings of an intricate nature or subject to heavy wear or high pressure are cast in nickel-iron alloy. At the rear of the main administrative offices is a series of shops, comprising the pattern shop and stores, non-ferrous metals foundry, welding and cutting shops, main machine shop bays, erecting and testing shops, smithy, coppersmiths' shop, and water- testing shop.
Power for the works is supplied from three power houses, two having been added to meet the increasing output of the works.
The first contains three Babcock boilers with a capacity of about 40,000 lb. per hour, fitted with chain-grate stokers, and three Brotherhood high-speed generating sets with a total capacity of 550 kw. The second, on the other side of the main building, contains four horizontal heavy-oil engines, two by Blackstone and two Brotherhood, with a combined output of 500 kw. The third, separate from the other buildings, contains a Brotherhood twin-cylinder heavy-oil engine of 150 kw. capacity, a 50 kw. Brotherhood Ricardo engine and dynamo, and a vertical suction-gas engine and 100 kw. dynamo. The supply throughout the works and offices is 220 volts d.c.
At present the firm's principal productions are high-pressure compressors for air and gas for the chemical industry, and auxiliary air service for motor ships; internal-combustion engines, including the Brotherhood Ricardo high-speed Diesel engine; steam-turbines; steam-engines; refrigerating machinery; and many other machines of a specialized character.
The use of fired clay as a building material and the consequent manufacture of burnt bricks have a history of some four-thousand years. Bricks are being made to-day in many cases by methods not far removed from those employed in the Babylon of Nebuchadnezzar. The operations of the company are of engineering interest in that the manufacture of hundreds of millions of bricks has been treated as an engineering problem, and the greatest possible degree of mechanization employed. The present daily output of four-million means that 75,000 tons of clay must be quarried and dealt with by the various processes every week. The company operates twenty works constituted into seven works groups; the works to be visited are in the Fletton (Peterborough) group.
The essentials of the company's process consist in reducing the raw material by grinding to a powder. After screening, mixing and any necessary humidification, the ground clay is fed automatically to the presses, which mould the bricks at high pressure between heated dies. This pressure is not applied in one motion but in four progressively increasing thrusts, hence the company's trade mark "Phorpres." The green or raw brick thus produced is of such strength that it may be stacked directly into the kiln without the preliminary drying required by other methods, thus effecting a large saving in handling and in time. The kilns employed and developed by the company are marked by the efficient use of all the available heat, and by the complete control over firing conditions which is possible; they operate in continuous cycles, and the burnt bricks are loaded directly into railway wagons standing alongside. A large number of auxiliary services are required, and the company operates its own foundry and engineering shops, drawing offices, and so forth.
Two forms of clay pit are in operation. The first employs the usual type of mechanical digger upon a straight pit face, with other excavators dealing with the overburden which is tipped back into the pit by a jib conveyer. The second pit is of a greater depth than can be worked effectively with a jib navvy, and a shale planer developed by the company in conjunction with Messrs. Ruston and Hornsby is employed: in these machines an endless chain fitted with cutting knives runs around a triangular guide, the longer side being in proximity and parallel to the pit face. Alternating with the cutters are flat steel plates which serve to scrape the cut material down the face and up into the loading hopper above the wagons. It will be observed that the machine is so designed that an effective batter is left to the pit face. The overburden is, in this case, dealt with by a drag-line excavator. In all, forty mechanical excavators are employed by the company.
Electric power from public supply undertakings is used in all works, a total of over 20,000 h.p. being required. The company employs 5,400 work-people, who participate in profits under a scheme whereby they are assumed to hold six shares for each year of service up to ten years: upon this notional holding is paid a bonus at the rate of dividend declared to the Ordinary shareholders. Recreation and the cultivation of the team spirit which is so essential in modern industry are encouraged by the provision of football, cricket and other sports grounds, and by financial grants towards the maintenance of the various sports clubs.
Peterborough Power Station occupies a site approximately four acres in extent, adjoining the River Nene and the L. & N. E. Railway, a siding from which is provided for delivery of coal. The coal wagons are emptied by a wagon tippler to a system of belt conveyers, which convey the coal either direct to the raw-coal bunker in the dryer house, or to either of two stacking grounds. One stacking ground is equipped with a belt conveyer with tripping arrangement for distributing the coal and a travelling grab-crane for reclaiming it; the other stacking ground is provided with a transporter of 90-foot radius which distributes the coal over the ground or reclaims as desired. The plant is simple in design and requires a minimum amount of labour for operation. Cooling water is drawn from the River Nene by vertical-spindle, electrically driven, remote-controlled centrifugal pumps, which are erected in a separate building on the river bank, the water being delivered through a cast-iron main to the power station.
The coal-preparation plant is housed in a building separate from the power station proper. It consists of a Ruggles Coles rotary coal dryer of 12 tons per hour capacity, and a multiple ball mill of the same capacity for pulverizing the coal, together with the necessary conveyers, etc. This building also contains the feeders and primary air fans for the supply of pulverized coal from the storage bunker to the boiler combustion chambers. The main building of the power station houses the boiler and turbine plant, the switch-gear for the control of the generating plant and for the distribution system of the Corporation, and in addition contains the electrical control plant for the Central Electricity Board's grid substation, which is situated on land immediately across the river. The Peterborough Power Station is a selected station under the Central Electricity Board's scheme.
The boiler plant consists of two 75,000-1b. tri-drum water-tube boilers with water-cooled combustion chambers fired by pulverized coal. There are four burners to each combustion chamber. No coal whatever is stored in the boiler-house; the primary air fans and coal feeders are placed in the separate coal-preparation building. In this building the coal is drawn from the storage bunker and transmitted by air to the burners on the boilers. Each boiler is provided with a control panel on which are mounted four complete sets of electrical controls, one for each burner. By means of these controls the boiler attendant operates the supplies of coal and primary air from the adjoining building and the supply of secondary air which is provided by fans adjacent to the boilers. Pressure-gauges, temperature recorders, CO2 recorders, steam-flow meters, etc., are all mounted on the control panel. The feed-water is automatically controlled by a feed regulator. The control of the boilers is thus rendered simple and efficient. Ashes and dust from the boilers are delivered to a sluice which conveys them underground to a separate pump-house from which they are pumped to settling ponds on the opposite side of the river.
The generating plant contained in the main building consists of two turbine-driven alternators, one of 6,000 and the other of 12,500 kw. capacity. The smaller set is driven by a single-cylinder impulse turbine and the larger set by a combined impulse and reaction turbine. The alternators in each case are provided with closed-circuit cooling. The high-tension switch-gear controlling the alternators and the feeders to the Corporation distribution system is of the cellular type, but the switch-gear provided for the control of connexions to the Central Electricity Board's substation is of the metal-clad type. The electrical control gear provides for the control of the whole generation and distribution and for the operation of the Central Electricity Board's substation, both on the 6,000 volt side and the 132,000 volt main transmission. The Central Electricity Board's metering equipment, on which all the financial transactions between the Board and the Corporation are based, is housed in the electrical control room.
The present buildings represent rather more than half of the completed power station as designed, The outstanding feature of the design is that the boilers and the generating plant are all housed in one room.
Cambridge railway station has recently been resignalled, and by the use of all-electric power two signal-boxes now do the work which formerly required five mechanical cabins. The two new boxes are known as the South and the North respectively. There is only one platform at Cambridge station, apart from four bay lines, and ordinarily, trains from the north use the south end of the single platform and trains from the south the north end. The complication of traffic movements thus entailed is centred at the scissors crossing in the middle of the station; but as it is often necessary to modify the customary routing of traffic the connexions at the south and north ends of the station and the scissors crossing are so arranged and signalled that the two roads through the station can be used in either direction. One of the noteworthy features of the signalling is the arrangements for safeguarding this reversible working.
The mechanical locking is placed vertically in front of the locking frame. The levers are distinguished by coloured handles: red for signals, black for points, and blue for the ground frame controls. The sequence of operations on moving a point lever is as follows. The signalman presses a push-button, and if the lever is free of its electric lock the lever number is illuminated. He then pulls the lever part way, the stroke being automatically limited. Current energizes the point motor, and after the points have worked correctly the overrun of the point motor generates a dynamic indication current to the signal-box. This frees the lever and automatically completes its stroke. Thus a point lever cannot be fully moved unless the points have responded correctly and indication received, in order to free the locking for the operation of other dependent levers. In the case of a signal lever, an automatic indication stroke-completion is only given for the "on" position of the signal.
The points are unlocked, operated, and locked by a 110-volt motor, acting through a series of gear-wheels, with a cam-operated point lock-blade connexion, also cam-operated drive-rod connexion to points. A pole-changer device is housed in one end of the gear-box for the purpose of mechanically changing, at the end of each switch operation, the direction of the motor for the automatic indication. All signals except those of the dwarf type are operated by motors. The majority have their mechanism fixed at the bottom of the post or at the base of the "doll" on brackets and gantries. The two groups of signals that protect the up and down through line at the scissors crossing have the "topmast" method of fixing, the mechanism of which actuates the spindle of the arm directly.
Six route indicators are included in the equipment, and of special interest is the arrangement whereby a short length of track circuit delays the action of the signal admitting a train to the main platform when it is clear only up to the home signals at the scissors crossing, so that the arm will not go to "clear" until the train is on the track circuit, thus ensuring that Rule No. 40 is automatically worked to.
Power is obtained from 128 accumulators charged by a generator driven by an alternating-current motor. One-half of the cells supplies power at the signal-box for point and signal operation, while the other half supplies current for lever locks, track circuits, detection, etc.
The plant at the pumping station consists of a low-pressure condensing beam-engine of 70 h.p. with a scoop-wheel of a capacity of 130 tons per minute, which was installed in 1850, together with a 140 h.p. semi-Diesel oil-engine and centrifugal pump.