1935 Institution of Mechanical Engineers: Visits to Works
Note: This is a sub-section of 1935 Institution of Mechanical Engineers
THE BATH CABINET MAKERS' COMPANY, LTD., FLIGHT WORKS.
The works were built during 1917-18 for the production of aircraft, but were designed with a view to their ultimate utilization as a furniture and joinery manufactory, and were converted to that use shortly after the Armistice. The buildings are solidly constructed of red brick, Bath stone, and concrete, and consist of six blocks; the central block is six stories in height and contains approximately 100,000 sq. ft. of workshop floor area.
Modern plant is employed in the manufacture of furniture, and the capacity of the works enables the firm to carry out large joinery and furnishing contracts for offices, shops, hotels, and public buildings. A speciality of the company is the supplying and fixing of panelling in oak, walnut, and mahogany.
CITY OF BATH ELECTRICITY WORKS.
Bath's electricity undertaking is one of the pioneers of the electricity supply industry. It dates back to 1888, when a small privately owned generating station commenced working on the site now occupied by the Empire Hotel. A new generating station was inaugurated and operated by the City of Bath Electric Lighting and Engineering Company in 1890 on the existing site, and in 1897 the undertaking was purchased by the Bath Corporation. A modern three-phase generating system was initiated in 1921 and the station is now "selected" to operate on the national grid.
The boiler house comprises one oil-fired and four coal-fired boilers having a total steaming capacity of 200,000 lb. per hour. Each boiler is of the water-tube type and is fitted with superheaters. Chain-grate mechanical stokers are fitted to the coal-fired boilers, with balanced draught fan equipments. Coal is fed from overhead bunkers, and a wet ash conveyer is installed in the basement. The working pressure of each boiler is 200 lb. per sq. in., with a steam temperature of 600 deg. F. The turbine house contains five turbo- alternators of the Brush-Ljungstrom type generating three-phase current at 6,600 volts with a frequency of 50 cycles per second. Circulating water for condensing purposes is obtained from the River Avon. The total generating capacity is 21,500 kW. The main switchgear is metal-clad, of the electrically remote-controlled type, and each unit has a rupturing capacity of 350,000 kVA.
During the last ten years the units generated have increased from 6,200,000 to 37,398,000 per annum. The generating station buildings, with the offices and showrooms, form an outstanding example of the adaptation of classic buildings in harmony with the eighteenth-century tradition of the city.
BATH GAS COMPANY.
The company, which was established in 1818, annually supplies over 1,300,000,000 cu. ft. of gas to 27,000 consumers in Bath and the surrounding districts. The gas is delivered through 210 miles of mains over an area of 106 square miles.
Coal is received in railway wagons in sidings connected with the London, Midland and Scottish Railway Company's lines, and is discharged by an electrically operated tippler into an underground hopper. The coal is fed from this hopper to the breakers, then elevated by twin elevators to a scraper conveyer extending the full length of the retort house, and delivered into the overhead storage bunkers, which are of 24 hours' capacity.
Carbonization is carried out entirely in horizontal retorts. The major portion of the gas is manufactured in a modern horizontal retort plant erected in 1926. The retort house building, which is a steel-framed structure with brick panelling, rests on a reinforced concrete raft supported on reinforced concrete piles 14 inches square and about 30 feet long. The building contains two benches of horizontal retorts, each consisting of seven settings of ten retorts each. The retorts are of D-section, 24 inches x 18 inches x 23 feet long, and arranged in pairs in five tiers. Each retort carbonizes 17l cwt. of coal in 12 hours. The retorts are of fireclay, the combustion chambers and transverse walls being of silica. The outside walls and top of each setting are faced with insulating bricks to minimize heat losses. Coke-fired producers, fitted with " Bath " grates, supply the necessary heat for the carbonization of the coal.
The retorts are operated by two combined charging and discharging machines by Messrs. Drakes, Ltd. The coke from the retorts is discharged on to a De Brouwer chain conveyer which delivers it to a cross-conveyer of similar type leading to the overhead coke- handling plant. Here the coke is first cut by a Cort coke cutter and then passes to the travelling screen where it is graded into various sizes and stored in separate overhead hoppers, which are arranged to deliver into railway wagons or road vehicles.
An additional retort house situated on the north side of the river consists of seventeen settings of eight retorts each. The retorts are of D-section, 22 inches x 16 inches x 20 feet long and carbonize 9 cwt. of coal per retort in 8 hours. They are operated by two Fiddes-Aldridge machines, one having the box type chain, while the other machine is of the central chain type. The coke from this house is conveyed to an overhead screening and storage plant by means of a De Brouwer chain conveyer.
The condensing plant consists of three water-tube condensers having a total capacity of 6,1- million cu. ft. of coal gas per day.
In engine room No. 1 there are three sets of coal gas exhausters, driven by horizontal reciprocating steam engines. One set is capable of dealing with 300,000 cu. ft. of coal gas per hour, whilst the other two each have a capacity of 230,000 cu. ft. per hour. The building also contains four sets of steam-driven gas compressors for supplying gas at high pressure to the outlying districts of Chippenham, Corsham, Saltford, etc., and also for feeding the low-pressure mains at outlying points throughout the district.
Two of the compressors are of the Belliss and Morcom reciprocating type, and each have an hourly delivery capacity of 200,000 cu. ft. The other two sets are rotary compressors, capable of delivering 150,000 and 55,000 cu. ft. per hour, respectively. The gas is compressed to a pressure of 10 lb. per sq. in.
The whole of the exhaust steam from the compressors and exhausters is condensed in a Belliss and Morcom multi-kinetic jet condenser. All pressure and vacuum gauges are mounted on one panel for convenience. A Morris 5-ton hand-operated travelling crane is available for lifting and transporting machinery when required. There are two sets of electrically driven ventilating fans, capable of giving four complete changes of air per hour. Oil filters are installed in the inlet air shafts to remove any dust from the air before it is brought into the room.
Four Lancashire boilers provide steam for the coal gas plant and compressors. Two of these boilers are 25 feet long by 7 feet diameter, and two 26 feet long by 6 feet diameter, and are equipped with Meldrum grates. River water is used, and as it has a hardness of about 20 deg. it is softened in a Paterson plant. The fuel is coke breeze, brought from the screening plant in wagons, elevated to a cross-band conveyer, and tipped into the bunkers above the boilers.
The coal gas, after leaving the exhausters, passes to the two Livesey washers, each with a capacity of 4,000,000 cu. ft. per day. It then passes through two Holmes rotary-brush washer-scrubbers of the same capacity, the first acting as an ammonia washer (using water as the extracting medium), whilst gas oil is used in the second washer for the extraction of naphthalene.
Hydrated ferric oxide is used in the cast iron purifier boxes for the removal of sulphur from the gas. The plant is in two units, each unit comprising four purifier boxes 40 feet x 30 feet x 6 feet deep and one catch box 40 feet x 25 feet x 6 feet. The gas flows downwards through two layers of purifying material each about 18 inches deep. Adjoining the purifiers is the oxide revivifying floor, which is covered by a steel roof. The oxide on removal from the purifiers is passed through a centrifugal disintegrator to prepare it for revivification and subsequent use.
The coal gas made is measured by three station meters; two are of the wet-drum type with capacities of 60,000 and 80,000 cu. ft. per hour respectively, and there is one Connersville rotary meter of 250,000 cu. ft. per hour capacity.
The carburetted water-gas plant, which is housed in a set of buildings comprising generator house, boiler house, and engine room, consists mainly of a generator, carburettor, superheater, wash-box, and condenser. There are two sets, each capable of producing 1,600,000 cu. ft. of carburetted water-gas per day, and one set with a daily capacity of 1,250,000 cu. ft. of blue water-gas.
The air blast for these sets is supplied by a battery of three Sturtevant rotary fans directly driven by de Laval steam turbines of which two are of 30 b.h.p. and one of 55 b.h.p. The steam for power and process work is supplied by three dish-ended Lancashire boilers, each 30 feet long by 7 ft. 6 in. diameter, fitted with superheaters. Weir feed pumps are installed in duplicate for supplying softened preheated water to the three boilers. The coke for the manufacture of water gas is brought from the screening plant in railway wagons and discharged into skips. The skips are then elevated by a hydraulic hoist to the charging platform for the generators.
There are two sets of exhausters, each with a capacity of 100,000 cu. ft. per hour. Each set is driven by a 27.5 b.h.p. horizontal reciprocating steam engine. The exhausters draw the gas from a single-lift relief holder of 80,000 cu. ft. capacity. A tar extractor removes the bulk of the tar before the gas passes to the rotary brush washer-scrubber for the extraction of naphthalene. The washing plant has a daily capacity of 3,000,000 cu. ft. Four purifier boxes, each 35 feet square by 6 feet deep, remove the sulphur from the gas, after which it is measured by a Thorpe rotary meter with a capacity of 80,000 cu. ft. per hour. The gas then passes on to meet the coal gas stream as it enters the gas holders.
The buildings just described also contain the electrical generating plant, comprising two sets of Belliss and Morcom compound steam engines, driving two open type inter-pole compound dynamos with shunt regulators. The engines work at a pressure of 120 lb. per sq. in., using superheated steam; the exhaust steam can be discharged to atmosphere or through a multi-kinetic jet condenser, driven by a 7 h.p. electric motor. The whole of the condensing plant is accommodated in the basement of the machinery room.
The two generators each supply 125 kW. at a pressure of 200 volts, d.c. The electrical energy is taken direct to a main switchboard by cables underneath the floor of the machinery room, whence it is fed by overhead insulated cables to the distribution boards, etc., in the works. This plant was installed to augment the existing generating plant—located in the lower portion of the main workshops—which comprises a 22.5 kW. 220-volt continuous current dynamo, driven by a 44 b.h.p. gas engine; the whole installation is in duplicate. A subsidiary switchboard in this power house enables the auxiliary plant to be thrown into circuit in place of the main plant, in the event of the latter being under repair or otherwise not working. The current from either power plant is fed through distributing and control boards to the forty-five motors distributed throughout the works.
Two single-inlet Rateau turbo-boosters are used to increase the gas pressure at periods of maximum demand. One machine has a delivery capacity of 500,000 cu. ft. per hour at 1,500 r.p.m. against a pressure of 12 inches water gauge and is driven by a 30 h.p. ventilated type of compound-wound motor. The other, which will deliver 750,000 cu. ft. per hour, is driven by a 45 h.p. motor and is similar in other respects. These machines are installed on the outlet main from the gasholders and maintain a constant pressure at the inlet to the station governors.
The crude tar from the storage wells is dehydrated for road- spraying purposes. Dehydration is effected by a Wilton coil still, working under a pressure of 60 lb. per sq. in. and a minimum temperature of 180 deg. C. The dehydrated tar is utilized as required in the manufacture of " Spatar," a well-known first-grade compound used for road making and dressing.
The gas storage capacity approximates to 6f million cu. ft. Two of the holders have a capacity of 1,225,000 cu. ft. each, whilst the largest holds 3,750,000 cu. ft. These holders each have three lifts and are column-guided.
There are well-equipped fitting and blacksmiths' shops for the general repairs of the machinery throughout the works and in addition there are meter and stove repair shops. A laboratory is centrally situated. Two locomotives (one in reserve) and a 5-ton crane deal with the coal, coke, and other traffic.
Showrooms, Offices and Distribution Department.- The premises comprising the showrooms, offices, and distribution department were recently acquired by the company and are situated in the centre of the city. They have been completely modernized and the showrooms architecturally designed in accordance with the nature of the exhibits displayed. The main showrooms and lecture theatre occupy the ground floor, whilst the basement is devoted to the display of cooking and water-heating apparatus. The executive offices, general offices, and board room are situated on the upper floor. The distribution offices and stores are accommodated at the rear of the building.
The building is heated and ventilated on the "Plenum" system, fresh air being drawn from outside through a battery of radiators by a fan and distributed through ducts to the various parts of the building. The vitiated air is also extracted by a fan, four changes per hour being arranged. The water for the radiators warming the air is heated in gas-fired boilers, thermostatically controlled. The boilers are in three units, one or more being operated according to requirements, and they have a total rating of 675,000 B.Th.U. per hour. Additional heating is provided by hot-water radiators and gas fires.
MESSRS. CHARLES BAYER AND COMPANY (1931), LTD.
The business was founded by the late Mr. Charles Bayer, who commenced the manufacture of corsets in 1870. The present factory is a red brick structure erected about forty years ago. There are five stories, each containing 8,000 sq. ft. of floor space, and care has been taken to ensure good lighting and ventilation. Electrical power is used throughout, and is supplied by the corporation. A new system of gas heating has recently been installed.
In the designing room, drawings and patterns for each new type of corset are prepared and transferred to the actual materials. The various sections are first pinned on to a dummy figure, and after final rearrangement are sewn together; the garment is then fitted on a human model. The types of garments manufactured comprise "hooksides," "wraparound," front-lacing and back-lacing models, corselettes, and two-way stretch corsetry incorporating "Lastex" yarn.
The stock rooms, in which the materials used in manufacture are stored, receive large quantities of cloth or broche, in various shades, the predominant one at the moment being tea rose; broche was formerly purchased from France, Germany, and America, but is now chiefly obtained from Lancashire. All widths of elastic are stocked, from garter or suspender web to surgical elastic 16 inches wide, and in all shades to match the broche; in addition there are large stocks of steels, ribbons, eyelets, suspender fittings, and other accessories. After inspection, the material passes to the factory to be marked out by means of cardboard patterns, laid on the upper side of a pile of 48 layers of cloth. The patterns are arranged so that cutting shall be "on the cross," and the operation is carried out on finch band knife machines.
After cutting, the material passes directly to the stitching room for making up. The work is highly skilled and is carried out chiefly on sewing machines having from one to four needles, according to the operation to be performed. The machines make twelve stitches to the inch and their working speed is from 3,500 to 4,000 stitches per minute. When seaming is completed, the garments are passed on for strapping; various widths of strappings for the reception of the bones are then stitched to the insides of the garments. The strapping is run through a gauge, ensuring perfect alignment.
Bones and steels are next inserted. This is done by hand, as great care is necessary to ensure that the various lengths are inserted in the correct positions. After boning, the garments, according to their type, pass on to the eye-letting machines, which punch the holes and impress the eyelets accurately, or to other machines which attach the hooks and eyes. Then they are bound, the suspenders inserted, and trimming affixed. Ironing or "pressing" is then carried out on machines having shoes which are raised and lowered by electrical means; after a final examination, the corsets are ready for boxing. An extensive warehouse is provided for the finished corsets which are awaiting dispatch. Foreign orders, an important item in the firm's business, are dealt with in an export section. In the counting house, the book-keeping is done on electrically operated machines.
A rest room is provided for the girls, who form the majority of the firm's employees. A first-aid department is also provided, and a matron is employed on the premises. In addition, a dining hall has been built which is a great boon to employees living in the outlying districts.
MESSRS. ISAAC CARR AND COMPANY, LTD., TWERTON MILLS, BATH.
The company manufactures the highest grade over-coatings for men's wear and lighter-weight coating cloths for ladies' wear. The men's wear cloths are chiefly heavy-weight types suitable for Canada and the U.S.A., while the lighter-weight products sell chiefly in England. All operations from the raw wool to the finished cloth are carried out at the company's two mills (Twerton Mill and Weston Mill), where from 4,000 to 6,000 yards of cloth are produced weekly.
The drive for the two mills consists of water turbines developing up to 150 h.p., according to the height of water available from the river. This power is supplemented by a Belliss and Morcom back- pressure engine coupled to an alternator generating three-phase current at 400 volts, the periodicity being 50 cycles per second. The machinery is driven by motors ranging from 1 to 100 h.p. and the two mills are connected by an underground cable. The engine exhausts at a pressure of 222 lb. per sq. in., and this steam is used for process work. In certain cases where high temperatures have to be reached, supplementary pressure steam is introduced and the pressure kept constant by means of an Arca regulating valve which is automatically controlled.
MESSRS. W. AND R. COOK, TWERTON.
The clothing factory derives power from a generator driven by a water turbine, arranged to run automatically in conjunction with the city electricity supply, through a switchboard of up-to-date pattern.
Over forty cutters are employed on bespoke tailoring in the cutting room. An electrically driven band knife will cut from thirty to forty layers of cloth at a time. An up-to-date system of Hoffman presses has been installed.
In separate sections of the factory, coats, vests, and trousers are made complete. Machines for buttonhole making, for sewing on buttons, for edge basting, and steam irons for under-pressing are provided in each section.
MESSRS. FORTT'S ORIGINAL BATH OLIVER BISCUIT FACTORY.
The original Bath Oliver biscuit was invented in 1735 by the celebrated Dr. Oliver, who was at that time physician to the Bath Mineral Water Hospital. The only biscuits then before the public were the "Captain" and the "Abernethy," and, no doubt, the success of the latter in some measure induced the doctor to turn his attention to the production of another first-class biscuit, which should be not only a novelty but a luxury, and an aid to digestion. The doctor, who died in 1764, bequeathed the secret of the composition of the biscuit to his coachman, who took a small shop in Green Street, Bath, and became its sole manufacturer. Eventually it came into the hands of the present proprietors, who for many years carried on the manufacture in the original house. The premises, however, had to be constantly enlarged, and a large factory with modern equipment was added in Manvers Street.
The old method of manufacture was known as the "staff brake." This was merely a staff of wood attached at one end to the side of a table or board, on which the dough was placed in such a manner as to allow of its being freely pressed. The dough was first thoroughly kneaded with the staff in this way; then each biscuit was weighed and moulded by hand, and, lastly, separately rolled with rolling pins. The staff brake in time became too slow and cumbersome for the purpose, and gave way to the steel roller. The principle was the same as that of a mangle, but it also had to yield to much quicker methods; its place was taken by machinery designed and introduced by the present proprietors.
In addition to Bath Oliver biscuits, many other biscuits are manufactured and sent daily to all parts of the country, as well as a large variety of cakes and confectionery.
THE HORSTMANN GEAR COMPANY, LTD., NEWBRIDGE WORKS.
The firm manufactures a wide range of apparatus for street lighting control. The basis of all these devices is a high-quality clockwork movement, practically every part of which is manufactured on the premises.
The plant consists of raw material stores, machine shops for the making of small turned and milled parts, power presses for making stampings, gear-cutting shop, heat treatment shop, chemical finishing and plating shops, and final assembly departments. All press tools, jigs, and gear-cutting tools are made in the company's tool room. The company also manufactures hardened plain cylindrical and screw gauges of the highest accuracy.
Another section of the works is devoted to the manufacture of gas switches for indoor gas lighting, principally for domestic use. An extensive variety of these switches is manufactured, including those utilizing a bypass for ignition; also a patented form of electro-catalytic ignition by which the necessity for a pilot is obviated. These switches are also being extensively applied to gas fires, thus obviating the use of matches or bending down to light the fire.
The company also manufactures a number of other gas appliances to special order for gas undertakings, including safety cut-off valves and patented constant-pressure governors. The company has been established for twenty-nine years and now employs about 300 hands.
SIR ISAAC PITMAN AND SONS, LTD., THE PITMAN PRESS.
The Press was established in 1888 to produce the publications of the parent company, and now handles all its own publications, in addition to those of other publishers, as well as general printing. It is capable of producing upwards of 100,000 books per week.
The printing trade provides matters of special interest to engineers, not only on account of the ingenuity of the machines used, but also the fine limits of accuracy to which they must be built. Especially interesting are the monotype casting machines which automatically adjust the spaces between the words so that every line of a book or page becomes exactly the same length; the screens of the process engraving cameras which are ruled by diamond point on the glass with from 150 to 200 lines per inch, in order to divide up the glass into minute panes so that the light is split up and gradations of light and shade can be reproduced, or colour values faithfully rendered; the large printing presses handling sheets 3 ft. 4 in. by 5 feet, where the type bed is "crowned" by 5/1,000 inch so that under pressure the type bed shall be perfectly fiat; the ink fountains for feeding the ink to the type, which are tested for accuracy to 1/40,000 inch; the trips and catches to stop the press if no sheet, or if more than one sheet, is fed to the machine, and the almost human movements of some of the bookbinding machines.
MESSRS. STOTHERT AND PITT, LTD. NEWARK WORKS AND VICTORIA WORKS.
The alterations in progress during the Bristol Summer Meeting in 1930 have since been completed. The large shop at the west end of the yard, which was built originally for munition work, is now used as a fitting shop for cranes and patent rotary pumps, of which the latter now form a very important part of the firm's productions. A pump testing department, with the necessary tanks and apparatus, adjoins the pump fitting shop. A large erecting shop 80 feet high and 170 feet long by 65 feet wide is situated in the centre of the works. This building is fitted with sliding doors, 50 feet high, along one side to enable dockside cranes to be completely erected under cover and moved out into the yard as required for test. The brass foundry and another fitting shop adjoin the erecting shop.
The structural department at the Victoria Works is served by four electric overhead travellers and contains high-speed machine tools for the fabrication of structural steelwork. Oxy- acetylene cutting machines and electric welding plants are used extensively. Riveting is done by pneumatic gap riveters and hand machines.. A templating shed nearby, in addition to a board in the side bay of the shop, enables all structures to be laid out full size and made to templates to ensure accurate work.
The iron foundry has a main bay 250 feet by 50 feet served by overhead electric cranes, with a side bay 100 feet by 30 feet for small castings. Castings of all sizes are produced, including non-corrosive alloys for special pump requirements. A well-equipped pattern shop and pattern stores are situated on the west side of the road.
The fitting shop is 300 feet by 50 feet and is used principally for the manufacture of concrete mixers and modern road-making machinery.
MESSRS. C. AND T. HARRIS (CALNE), LTD., CALNE.
The firm, which originated the style of cure known as Wiltshire bacon, based upon the dry cure, was founded in 1770. Recently, however, the developments of the Pigs and Bacon Marketing Schemes have caused the firm to provide up-to-date machinery and white tiled tanks for curing in the Continental style, known as "tank cure." A comparison between the methods of curing is of interest.
Pigs arrive daily, by road or rail, and are subject to ante- and post-mortem examination by a qualified whole-time veterinary surgeon. After slaughter the carcases are transported along rails to the scalding room, where they are scalded and the hair removed, after which the skin is scraped by machinery. They are then scrutinized by the veterinary surgeon and those which pass his inspection are allocated to the various departments, where they again pass through an inspection to qualify for curing into hams and bacon. The sides are trimmed and are transported by mechanical means to the cooling and curing cellars, which are some of the largest in the country, and are capable of holding approximately 80,000 sides at a time. The most up-to-date refrigerating machinery is employed to maintain these vast cellars at the correct temperature. After salting and maturing, the hams and sides are hung in the smoke stoves for two or three days, where specially prepared sawdust only is used. The sides are then again classified by the packer into the various grades to meet the requirements of the trade.
In the separate and enlarged factory devoted to the preparation of small goods (which are manufactured in many varieties to meet the increasing demand for cooked foods) the perfect sanitation and cleanliness are notable. All raw material purchased for manufacture is carefully examined by the laboratory staff and any not up to standard is rejected.
The factory is entirely self-contained as regards power. The power plant, housed in a central station built beside the river running through the middle of the company's property, consists of a battery of four 30-foot by 8 ft. 6 in. Lancashire boilers, fitted with economizers and superheaters generating steam, mainly for process purposes, at 160 lb. per sq. in. pressure and about 450 deg. F. total temperature. A Stirling boiler, working in parallel with the Lancashire boilers, and generating steam at 225 lb. per sq. in. pressure and 710 deg. F. total temperature, is a recent addition, installed mainly to supply steam for the turbo-generator which was added at the same time. All high-pressure steam surplus to power requirements is passed to the process steam main through an Arca regulator (controlled on both the high-pressure and low-pressure sides) and de-superheater.
The main electric power unit is a Belliss and Morcom "Compact" type turbo-generator of 800 kW. capacity, supplying direct current to the main switchboard at 220 volts. For standby there are two Howden high-speed reciprocating ejector condensing sets, each of 400 kW. capacity. Besides supplying all domestic requirements the plant also provides current for distribution through the Corporation Electricity Department.
A noteworthy feature of the power station equipment is the refrigerating plant. This is a layout of three vertical enclosed twin-cylinder York ammonia compressors, arranged with their respective motors and controllers "in line ahead," the auxiliary water pumps being arranged alongside "in line abreast," leaving a gangway between. A vertical shell and tube ammonia condenser and a receiver are arranged over the river, outside the engine room wall, and a herring-bone coil evaporator with the necessary brine circulating pumps is arranged on a platform over the economizer and water-treatment plant at the opposite side of the engine room. Complete supervision and temperature control of all refrigerator rooms, and also of a fully automatic ammonia refrigerating plant and a dry cold-air battery installed at a distance, is exercised from the engine room by means of the switchboard instruments and electrical distance thermometers.
For the purpose of supplying power to the by-products plant, about mile away, there is a motor-generator set of 100 kVA. capacity, generating three-phase alternating current at 400 volts with a frequency of 50 cycles per second. An automatically controlled compressed air plant, arranged in duplicate, supplying compressed air at a pressure of 80 lb. per sq. in. for a variety of purposes; completes the equipment.
Adjacent to the power station is the maintenance department - a fine single-story glass-roofed building—in direct communication with all parts of the factory and equipped with all the machine tools and apparatus necessary to a modern engineering works of this size. Advantage has been taken of oxy-acetylene welding and cutting to such an extent that this equipment is now practically indispensable.
THE WESTINGHOUSE BRAKE AND SIGNAL COMPANY, CHIPPENHAM.
Westinghouse Brake and Signal Co
The brake works at York Road, London, were moved to Chippenham in 1933. Advantage was taken of this amalgamation to reorganize, extend, and re-equip the buildings, which are, therefore, up to date as regards plant and equipment. In 1935 the name of the firm was changed to the Westinghouse Brake and Signal Company. The factory now occupies an area of 13 acres, and the areas of the chief departments are now as follows : foundries, iron and non-ferrous, with pattern shop, and stores, etc., 63,000 sq. ft.; smithy and drop forging, 18,000 sq. ft.; machine shop, 45,000 sq. ft.; assembly shops, 53,500 sq. ft.; instrument shop, 12,200 sq. ft.; rectifier shop, 29,000 sq. ft.; woodworking shop, 16,000 sq. ft.; structural steel and fabrication shop, 18,000 sq. ft. Approximately 1,700 people are employed.
MESSRS. JOHN B. CHAMPION AND SONS (DURSLEY), LTD., DURSLEY.
The firm changed hands two years ago, since when the works have been entirely reorganized and modernized. They are devoted principally to the production of reversible wool carpets, rugs, and mattings.
MESSRS. HUNT AND WINTERBOTHAM, LTD., CAM MILLS, CAM, GLOS.
The process of manufacture of woollen and worsted cloths remains substantially the same as when members last visited these mills. An interesting point brought out on this occasion is that wool is extremely hygroscopic. Its normal moisture content is about 16 per cent under ordinary atmospheric conditions and, to secure the best results, the manufacturer should endeavour to complete each process so that the material possesses as nearly as possible this normal moisture content.
MESSRS. R. A. LISTER AND COMPANY, LTD., DURSLEY.
The firm manufactures industrial, electrical, and agricultural machinery, the chief products being vertical cold-starting solid- injection Diesel engines ranging from 3 to 38 h.p., also petrol and paraffin engines of the vertical four-stroke stationary type from 1 to 20 h.p., electric generating plants, petrol-driven three-wheel industrial transport trucks and commercial narrow-gauge petrol-driven locomotives, cream separators, churns, butter moulders, butter workers, and other dairy equipment, in addition to sheep-shearing machinery, harrows, ploughs, etc. Vertical cold-starting Diesel engines and petrol engines for marine propulsion and auxiliary purposes are also manufactured. A new extension to the works has recently been opened to cope with the cream separator business, the firm being the largest manufacturers of this type of machinery in the country.
The company has been a pioneer in industrial welfare, and the works are equipped with a dental and medical clinic. A recreation and social club company has been formed, in which the employees are the shareholders. The club is well appointed for indoor amusements; in addition there is a hall with seating accommodation for over 900, and the playing fields cover more than 12 acres. The firm has set up a joint board at which employee directors, elected by their fellow employees, discuss with the directors of the company questions appertaining to the general efficiency of the works and the welfare of the employees.
THE BRISTOL AEROPLANE COMPANY, LTD., ENGINE DEPARTMENT.
The Engine Department of the Bristol Aeroplane Company, Ltd., was formed in 1920 with a personnel of thirty-four and installed in a factory having 15,000 sq. ft. of floor space, situated on the company's private aerodrome at Filton. The department now occupies 250,000 sq. ft. of floor space and employs over 2,500 men.
Since acquiring the designs and patent rights of the "Jupiter" engine in 1920, the engine department has concentrated upon the production and development of the nine-cylinder single-bank air-cooled radial engine, and its activities in this sphere have had a marked influence upon the technical development of this type of aero-engine. During the first ten years, eleven series of the "Jupiter" engines were evolved, followed by the improved "Mercury" and "Pegasus" engines, of which there have been several series. Since the inception of the engine department the progress that has been achieved with the same cylinder capacity, due largely to the steady development of thermodynamic technique and the evolution of better materials and fuels, may be summed up as follows. The output per litre of cylinder capacity has been increased 130 per cent; the specific weight, in spite of the addition of airscrew reduction gearing and supercharger, has been reduced 40 per cent; brake mean effective pressures have increased from 112 to 185 lb. per sq. in.; fuel consumption has been reduced 25 per cent; and maximum crankshaft speeds have been increased from 1,625 r.p.m. to 2,925 r.p.m. in the case of the "Pegasus" series, and to 3,125 r.p.m. in the case of the "Mercury" series.
The designs of the engine department have been widely accepted abroad by foreign manufacturers and at one period no fewer than sixteen countries had acquired manufacturing licences, while at present considerable quantities of "Mercury" and "Pegasus" engines are being produced in various European countries.
The factory is the most up-to-date and completely equipped factory in Europe solely engaged upon the production of aero-engines. The production capacity at present is about 1,000 engines per year, and plans have been prepared for substantially increasing this amount in times of emergency. The main machine equipment is largely driven by electricity, but during recent extensions machines having individual electric drives have proved to be of advantage, and a considerable proportion of this type are now in use.
There exists also an extensive research and experimental organization which is self-contained and highly specialized. This provision gives scope for intensive development work to be carried out. The general production and experimental work of the factory is assisted by supplementary sections, including the design department, the chemical and metallurgical laboratory, the aluminium foundry, the engine test department, the installation department, and an extensive scheme of inspection and stores which ensures the highest quality in production and experimental work. Provision is made for carrying out all necessary material process work, and treatments, including cadmium and chromium plating, etching, various heat treatments, and similar requirements.
As a result of research upon original lines, the principal developments of the experimental department are the " Phoenix " compression-ignition engine, which holds the world's height record for this type of engine, and the " Aquila " and " Perseus " sleeve valve engines, which were exhibited at the Paris Salon in 1934.
MESSRS. J. S. FRY AND SONS, SOMERDALE.
Messrs. Fry, after being in business in Bristol for over 200 years, have now transferred their factories and registered offices • to the new garden village of Somerdale, which is about 6 miles from the Guildhall, Bath.
The development of Somerdale Factories and Village began in 1921. The first transfer from the Bristol Works occurred at the beginning of 1924 and has continued as each new factory has been completed, until the early part of 1935. Therefore, so far as accommodating the manufacturing and administration departments (affecting about 5,000 employees), Somerdale can now be considered complete, but provision has been made for additions to meet the increasing demand for the firm's products, without modifying the general layout of factories, gardens, and playing fields.
Somerdale is pleasantly situated on the banks of the River Avon, and the total area is about 450 acres. The factories have been constructed on scientific lines and up-to-date machinery has been installed for the production and handling, through all stages, of edible and allied products.
An interesting feature of Somerdale is its gardens, which are interspersed among the factories and the adjoining playing fields.
KEYNSHAM PAPER MILLS, LTD.
The mills are of recent construction, building operations having been commenced in July 1932 and completed in August 1933. They are situated on the River Avon, approximately half way between Bath and Bristol, and were built by Messrs. E. S. and A. Robinson, Ltd., makers of paper bags, cardboard boxes, and specialists in high-class printing, for the primary purpose of supplying the firm with the paper, which was formerly purchased from Scandinavia, for their bag factory. The site is well placed; it has an ample supply of water, is adjacent to the main line between Bristol and London, and is also within easy reach of important coalfields.
Wood pulp is the only raw material used, and only one class of paper is made, this being known as "M.G." (machine-glazed), as distinct from a paper which is glazed on separate calenders. The machine has a width of 160 inches and its most interesting feature is the glazing cylinder, weighing 65 tons, and believed to be the heaviest and largest paper-machine glazing cylinder in the world.
All the power used on the site, except for week-end services, is produced from two Babcock and Wilcox boilers with a capacity of 30,000 lb. per hour, working at 300 lb. per sq. in. One 1,750 kW. Fraser and Chalmers turbo-alternator of the pass-out type is installed. This generates current at 3,300 volts, at which pressure it is used for all motors rated at 50 h.p. and above. For motors having a lower rating, the voltage is transformed to 400, current for lighting being supplied at 230 volts. All portable tools and lights are supplied from a separate 100-volt d.c. circuit, provided by a small motor-generator set. The coal is delivered by rail and grabbed direct from the trucks by a Strachan and Henshaw telpher plant with a capacity of 25 tons per hour, and delivered to the overhead bunkers. A very complete water-softening plant, having a capacity of 20,000 gallons per hour, has been installed for treating all process water in the mill. The water for condenser and mill purposes is obtained from the River Avon, through Mather and Platt pumps, and conveyed to the mill through an 18-inch underground steel main.
THE AVON INDIA RUBBER COMPANY, LTD., MELKSHAM.
A Babcock and Wilcox boiler with Bailey water walls has recently been installed. The evaporative capacity is 30,000 lb. per hour, and the designed working pressure 450 lb. per sq. in. In addition there is a coal- and ash-handling plant, a 375 kW. back-pressure turbo-generator, a new electrical substation, a water-softening plant, hydraulic pumping equipment, and air compressors. An interesting motor drive, with dynamic braking, has been installed for a rubber-compounding machine, and is supplied with alternating current at 3,000 volts. The speed is 98 r.p.m.
MESSRS. SPENCER (MELKSHAM), LTD., MELKSHAM.
The works of the company, which are now 32 years old, remain unchanged since they were described on the occasion of the Summer Meeting in Bristol in 1930.
WILTS UNITED DAIRIES, LTD., MELKSHAM CONDENSORY.
This depot, which was established over fifty years ago, now forms one of the firm's chain of similar factories operating in the country. Condensing at the depot commenced over thirty-five years ago, and the quantity of milk handled has gradually increased, necessitating in recent years extension of the factory and of operations in every direction. The area of the site is approximately 34. acres, almost entirely covered; the operations consist of milk cooling, cream production and processing, condensing under vacuum, the filling of condensed milk into tins,' and the making of the tin containers.
The plant incorporates many of the most recent applications of engineering to the food industry, which enables manufacture to proceed under the most hygienic conditions. On the power side, a mechanical coal-handling plant is installed, feeding four Babcock and Wilcox water-tube boilers fitted with chain-grate mechanical stokers, and having a total evaporative capacity of 27,500 lb. of steam per hour. Steam is generated at 120 lb. per sq. in. and supplies one 150 kW. direct-coupled high-speed vertical engine and generator, and two similar sets of 50 kW. each, all working at 15 lb. per sq. in. back pressure. In addition there is a direct-coupled Diesel generator set of 85 kW. Electric drives are employed throughout.
The refrigerating plant consists of three compressors, with a total capacity of 1,500,000 B.Th.U., two motor-driven direct-coupled sets and one direct-coupled Diesel machine. The compressors and many other items of plant and machinery were made by the sister company, the U.D. Engineering Company, Ltd. Both the steam ejector type and the reciprocating double-action piston type of vacuum pump is installed, each pump discharging approximately 30,000 gallons per hour. The back-pressure steam from the generators is employed for process work, and is augmented with steam at boiler pressure. The vacuum pans are capable of carrying out process work at an output of 1,100 gallons per hour.
The can-making plants are capable of producing cans at a speed of 120 and 300 per minute respectively, and the can-filling machines and the seamers deal with 100 cans per minute. An extensive conveyer system enables the full cans to be delivered to the various stores before being labelled, and the subsequent labelling is conducted on machines at a speed of 80-110 cans per minute. Box-printing and box-making machines are also installed.
All water used in the factory passes through filters of 16,000 gallons per hour capacity, and is subsequently sterilized chemically. A pure air system is installed ensuring a supply of filtered air to all rooms devoted to process work. In order to avoid erosion of the river bank in time of flood, a heavy concrete retaining wall has been constructed and is continued with steel piling.
Milk is collected over a radius of about 20 miles by a fleet of the usual standard lorries, milk tanks, and articulated lorries; this form of transport is also employed for certain other goods inwards and outwards. Chemical and biological laboratories furnish data for the control of the process work, the cleanliness of the plant, and the testing of the raw material and finished products.
GREAT WESTERN RAILWAY COMPANY, LOCOMOTIVE, CARRIAGE, AND WAGON WORKS, SWINDON.
THE LOCOMOTIVE WORKS.
A number of improvements have recently been effected in the works, resulting in more economical operation and increasing the rate of production. In "A" machine and fitting shop modern milling machines have been installed for dealing with coupling and connecting rods, while in "W" cylinder and machine shop the slotting of frames on machines is now preceded by cutting approximately to shape by means of oxy-coal gas jets, after which the frames are slotted to the finished dimensions in batches of ten. A special machine, with four radial heads, drills all holes in the frames. Improvements in "V" boiler shop include the gradual replacement of compressed air by electric power for driving the machines and the introduction of the oxy-coal gas process for cutting out boiler plates and shaping the edges.
A concentration yard has been laid out to facilitate the central handling of all general scrap, including the cutting up of condemned locomotives, boilers, tenders, etc. A large building has been erected and contains a 25-ton overhead crane, plate-bending rolls, shearing machines, and the necessary compressors, acetylene generator, oxygen mains, and electric lifting magnets. Dismantling of engines and boilers takes place in this building, and the parts are sorted into the respective classes of scrap. Three Goliath electric cranes, with capacities of 3 to 10 tons, are installed in the yard for stacking and for loading material into wagons. Sidings are also laid out for coal and coke stacking in this area. In a protected area a drop ball handled by an electric Goliath crane is used for breaking up large castings.
The spring shop has been completely remodelled. The furnaces are gas-fired, the temperature of each being automatically controlled.
To provide the oxygen used in the cutting and welding processes, a plant has been installed for the extraction of oxygen from the atmosphere by the liquid air process.
Centralized control of the transport of materials in the works has been introduced, and the transport equipment includes a large number of petrol-electric and petrol-driven trucks, all of which can be utilized with trailers.
CARRIAGE AND WAGON WORKS.
A new saw mill and new timber-drying kilns have been installed. The latter are arranged on the Sturtevant compartment system, securing the three essentials of an artificial seasoning plant, namely, controlled air circulation, heat, and moisture. In the stamping shop, all kinds of forgings formerly produced by the smith are now stamped out by dies. The steel dies are machine-cut in an automatic machine which has superseded hand-cutting.
A disinfecting plant for killing vermin and destroying bacteria in coaches and other vehicles, especially those for conveying flour and grain, has been built, and consists of a steel cylinder 85 feet long and 16 ft. 6 in. in diameter, fitted with a railway track upon which the vehicles to be disinfected are run, without having to be dismantled in any way.
WELFARE AND RECREATION.
A sports ground of about 13 acres was opened in May 1931 on the outskirts of the town, and this is managed by the G.W.R. (Swindon) Athletic Association. It has a cricket ground, tennis courts, bowling green, and an outdoor miniature rifle practice range. A fine pavilion has just been erected, and includes a skittle alley, recreation room, baths, and a refreshment bar.
MESSRS. KEMP AND HEWITT, LTD., TROWBRIDGE.
The wool used in cloth-making in the firm's mills is either Australian or South African, and arrives in bales containing the fleeces as they come from the sheep's back. A fleece contains two or three qualities of wool, the finest coming from the loins and shoulders, and the coarsest down the legs; sorting is therefore necessary to keep the blends standard. The animal grease, which may amount to half the weight of the natural wool, is then extracted in a series of bowls containing soap, alkali, and warm water. The wool is propelled gently through the bowls on the teeth of swinging rakes, and, after drying by hot air, passes to the dyeing vats. The firm's cloth is "dyed in the wool," as opposed to "dyed in the piece"; the former method, though rather more costly, secures better penetration. Dyeing is carried out in copper vats, the dye being heated to a certain temperature, and stirred continuously by wooden poles. The wool is dried again, and is then "blended." In the case of a grey, the black wool and the white are laid in alternate layers on the floor, sprayed with oil and water, mixed, and fed through a machine in which the matted fibres are opened out. The machine consists of a cylinder about 4 feet in diameter, studded with fine steel hooks, on which the wool is carried round while it is worked upon by three similar but smaller cylinders revolving in the opposite direction. The next operation is carding. Three or four carding engines constitute a "set "; each machine comprises a large cylinder covered with very fine wire, which carries round the blend fed on to it. A smaller cylinder revolving very slowly in the opposite direction takes the blend, and is relieved of it by another, which returns it to the main cylinder. This occurs five times, until the wool, now appearing as a fine web, is stripped off the last cylinder by a steel comb. A small overhead conveyer takes the rope of web to the next engine; the process is repeated and the web is taken to the third engine. On leaving the last cylinder, the web is divided into small strips which pass through leather rubbers that rub them into soft loose yarn, called " sliver," which is then rolled on to long horizontal spools.
The yarn is spun into thread on the spinning mule, which consists of a carriage containing about 400 spindles in front of a framework holding the spools from the carding engines. Each thread of sliver is attached to a spindle. When the carriage starts to retreat bodily on wheels and rails, a few feet of sliver are unwound from the spools. The sliver is held firm, and the carriage retreats further, drawing the sliver out while the spindles twist it to strengthen it; when the carriage is withdrawn to its greatest extent the spindles revolve very fast, twisting the yarn into a hard firm thread. Allowance is made for the shortening of the thread—caused by twisting—by advancing the carriage slightly. Then the machine stops for a second, and the carriage runs in, winding the thread on to bobbins on the spindles. The size of yarn is regulated by the weight of wool fed to the carding engines per minute, and by the distance the sliver is drawn out on the mule.
Weaving is carried out on looms in which the warp consists of about 100 bobbins of yarn. From each of these 62 yards (or other required length) of thread are wound on to a wooden drum 7 or 8 feet long. The threads are cut off, and a further 62 yards is wound close to the first batch, the process being repeated until the drum, or "warping bar," is covered. The threads, numbering up to 4,000, are wound on to a roller, which is then fixed into the back of the loom, and are then passed through thin looped wires. The order in which the wires rise and fall governs the pattern of the cloth.
The oil, sprayed into the wool before carding, is removed at this stage by scouring in wooden tanks filled with a solution and fitted with heavy rollers between which the cloth passes until it is clean. The next process is "milling," to shrink the cloth in width and to make the texture finer. The piece, saturated with soap, is put through a mouthpiece and run between two rollers, the upper roller being heavily weighted, for about twelve hours. It passes into a narrow trough, and is repeatedly pushed back by a heavy tongue. The rollers shrink the cloth in width, while the compression caused by the trough and tongue shrinks it in length. Ina box cloth the width is thus reduced from 100 inches to 54 inches, and the length from 50 yards to 40 yards. The piece is again scoured to remove the soap and is then dried by feeding each selvedge on to an endless chain of hooks, which carry the cloth between coils of steam pipes.
Cloths requiring facing are taken to a "gig mill," consisting of a top and a bottom roller and a large cylinder on which teazles are mounted. The cloth is pulled from the bottom to the top roller, passing the teazle cylinder which revolves rapidly in the opposite direction, raising and laying the wool, and giving the cloth a "face." Lustre is imparted by rolling up the piece tightly and immersing it in water for four or five days. Cropping is then carried out to cut off the wool made rough in milling. The action is similar to that of a lawn mower, except that the cloth moves under the blades, instead of the blades moving over the cloth.
Finally the cloth is damped, folded between sheets of stiff cardboard, and pressed for about twelve hours, after which it is examined yard by yard by experts, and then measured and rolled up for dispatch.
MESSRS. PALMER AND MACKAY, LTD., TROWBRIDGE.
The early type of steam engine with a wooden beam was in use in the firm's mill within living memory. Later, producer gas engines and condensing steam engines were installed; the latter have now been replaced by a high-speed enclosed steam engine and generator.
MESSRS. APLIN AND BARRETT, LTD., YEOVIL.
The company commenced trading on the present site in 1898 and from its inception steady progress was maintained, necessitating the subsequent erection of additional factories at London, Westbury (Wilts), and Frome. The parent works consist chiefly of two main buildings occupying approximately 3 acres and separated by a roadway for incoming traffic; in the block nearest the railway station are housed the departments dealing with butter, milk, fancy cheese, and other dairy products.
Milk is collected daily from neighbouring farms by the company's lorries, brought into the creamery for process work and pasteurizing, and subsequently converted into butter, cream, cheese, etc. An inspector visits the farms to ascertain the standard of hygiene and the health of the herds. Practically every phase of dairying is carried out, several departments being concerned in manufacturing various kinds of fancy cheese, which are packed and wrapped by ingenious automatic machinery. Other departments in this building are the laboratories, general stores, printing department, box- making rooms, refrigerating plant, power house, and cold storage. The main offices are also situated on the top floor, where over 130 clerks are engaged.
The other building, which was entirely rebuilt in 1932-3 on up-to-date lines, is used almost exclusively for meat products, and has a frontage of 64 feet. The building is faced internally throughout with glazed bricks. It comprises model kitchens, bakeries with electric ovens for veal and pork pies; while in other departments are manufactured various packed table delicacies ranging from sandwich pastes to Christmas puddings. Electric lifts and overhead conveyers are used to transport the goods from one department to another, and the various classes of foods are prepared, packed, cooked, and labelled, practically untouched by hand.
The staff employed at Yeovil works numbers approximately 600, and in the aggregate (including those at other factories, branch creameries and distributing depots) the staff numbers approximately 1,350.
MESSRS. PETTERS, LTD. WESTLAND WORKS, YEOVIL.
The machine at present in production at the Westland Aircraft Works for the Royal Air Force is the "Westland Wallace," a general purpose machine, used for bombing reconnaissance, army co-operation, etc. The works have also produced the "Pterodactyl," an interesting tailless type of machine which, it is considered, has great possibilities.
YEOVIL AND DISTRICT ASSOCIATION OF GLOVE MANUFACTURER
Glove-making involves an amount of time and labour not generally realized, for it is a matter of from six to eight weeks before the raw skin can be worked into finished leather, after which the operations of glove-cutting and making occupy perhaps an additional two weeks before the finished articles are ready for dispatch.
The raw skins are soaked, scraped, and generally treated for the removal of dirt, grease, and wool. They are then subjected to various processes for manufacture into leather, after which they are stoved and dried and then " staked "; the latter operation is performed either by hand or machine, and involves the softening of leather from the dried stage by drawing it in a damp prepared state over a crescent-shaped knife, thus removing all particles of flesh. The leather is then softened and " stuffed," after removing excess natural grease, when it is ready for dyeing.
The dyeing was formerly performed by wood and bark dyes alone, as these were not so fugitive as anilines, but in the modern pickle grain finishes, aniline predominates. The leather is again stoved, dried, and re-softened for "wheeling," after which it is given a grain or suede finish, according to its quality. It is then re-sorted and graded. In glove-making, the cutter works the leather to measures and pulls it into shaped pieces. The gloves, or "tranks," pass on for sewing, but before this can be done, the imprint of the fingers must be stamped through the leather, to guide the machinist. The gloves are then ready for "pointing" or backing, after which the sewing is completed. After examination the gloves are paired, and buttons or domes are added; they are then boxed for the wholesale dealer, after having passed through a total of seventy-two operations.
The craft of glove-making has been handed on from generation to generation for some 400 years, and throughout a wide district around Yeovil the villagers may be observed sewing gloves in their homes.
The works visited were those of Messrs. Atherton and Clothier, Ltd., Messrs. Blake and Fox, and Messrs. Whitby Brothers, Ltd.
See Also
Sources of Information