Vacuum News

One of the uses of Aerolift vacuum lifting equipment which is being manufactured and sold in the UK by Bridon Aerolift

furnaces manufactured by General under Licence from R D Brew Et Co of the United States of America.

General see their Heat Treatment Shop as a vital adjunct to their sales and manufacturing programme in furnaces. They feel that only the tip of the iceberg is showing as far as vacuum heat treatment is concerned and that half the battle in selling any vacuum furnace is firstly to sell the process. The Heat Treatment Shop will, therefore, be used to a large extent to treat customers samples for subsequent evaluation, to establish the correct processing parameters for a given job, and to treat small quantities of components on a regular basis for customers whose throughput does not justify the purchase of a furnace.

General Engineering (Radcliffe) Ltd Circle number 45 on Reader Enquiry Service card

Dust-collection system for giant new power station BVC Ltd designed, manufactured and installed the surface and bulk dust handling vacuum plant in the South of Scotland Electricity Board’s giant new coal-fired power station at Longannet.

Largest single undertaking in the SSEB’s building programme, Longannet power station represents more than half the total generating capacity of all the Board’s other power stations and is the biggest single engineering project ever to be carried out in Scotland.

Situated near Kincardine, on the north bank of the River Forth, Longannet is capable of producing 2,400,OOO kW. Each of its four boilers uses more than 200 tons of coal an hour.

The BVC installation comprises : three 70 hp D.9 exhauster units; two 12ft diameter primary interceptors or pre-collectors; one 12ft diameter final filter unit; three automatically-controlled rotary dust-conditioners for waste disposal ; approximately 15,000ft of pipework and a total of 206 hose-connection points.

Each pre-collector is connected by means of fixed pipe-work to 75 bulk hose-connection points (dual purpose outlets serving 4 in. or 2 in. hoses) and 28 2-in. hose-connection points for surface cleaning. The pre-collectors can be used individually for bulk handling in conjunction with the final filter unit, suction being provided by two D9 exhausters.

The plant is designed basically to handle more than IO tons of dust an hour from any boiler with six operators working simultaneously, or, alternatively, for multi-operator surface cleaning duty.

Storage capacity of each pre-collector is 30 tons and the final filter unit accommodates 10 tons of boiler flue dust. All but the finest particles are intercepted by the pre-collector, the final filtration being achieved by means of banks of multiple ceramic filter tubes housed above the container of the final filter unit.

The three containers are mounted above the roadway between the walls of the boiler house and the electrical annex. Below each container is the dust-conditioner. This is based on a Wingate turbomixer fed by a rotary valve where the dust is mixed with water to form a slurry for discharge into disposal lorries. BVC have converted this unit to give automatic mixing and discharge in batches at pre-selected intervals. The discharge rate is 20 tons/hour per container.

BVC Ltd have had a long association with the British electricity generating industry, having installed large capacity boiler cleaning systems at a number of CEGB and Scottish generating stations. Other installations for the SSEB include those at Barony and Kincardine. The system at Longannet was completed in co-operation with the SSEB’s engineering consultants, Merz 8 McLellan.

BVC Ltd Circle number 46 on Reader Enquiry Service card

Self-retained pins are tamper-proof, won’t fall out A self-retaining pin, which automatically locks in place when it is installed and which cannot be removed without a special tool, has been introduced.

Known as the Quick-Click system, the new pins were designed as replacements for clevis pins with cotter pins or clip rings. A circular, C-shaped spring located in a tapered neck at the point end of the pin compresses in the deepest part of the taper as the pin is pushed into place and expands to resist back-out when the pin is completely assembled.

When using clevis pins, the installer may forget to assemble the cotter pin or clip or may forget to spread the cotter pin. The clevis pin may then drop out, creating a hazard or resulting in expensive downtime while repairs are made. This cannot occur when the Quick-Click system is used because the circular spring automatically expands when the pin is pushed home, holding the pin firmly in place.

A finger pressure of 4 or 5 lb is all that is needed to install the Quick-Click system. As the pin enters the hole, the pressure pushes the spring back to the smallest diameter of the tapered-neck portion of the pin, where it easily compresses to allow the pin to be pushed completely through the hole. As the

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Vacuum News

end of the pin exits from the far end of the hole, the spring expands to larger than hole size. Attempts to push out the pin without the removal tool cause the spring to ride up on the larger end of the tapered neck, where it cannot be compressed. Since it won’t compress, it holds the pin firmly in place. Removal force without the special tool is more than 2800 lb for the 9/l 6-in. pin and 220 lb for the small No 10 pin, thus the Quick-Click pin is tamper-proof under most circumstances.

By contrast, the simple cylindrical removal tool which fits over the end of the pin permits the pin to be removed with about the same force as is needed to insert it. The tool locates the spring against the flange at the smaller diameter of the tapered neck and, as the tool is pushed, permits the spring to compress, allowing the pin to be pushed out of the assembly. No more force is required to install or remove a larger pin than a small one.

A Quick-Click pin can be installed in the average assembly in about six seconds, or approximately half the time required for a clevis and cotter pin. Because of this fast installation, in-place cost of the Quick-Click pin is seldom more, and is often less, than that of clevis pins with cotter pins or clip rings.

The Quick-Click pin can be used to replace clevis type or similar pins in any axle or pin application, including control linkages of all types, roller chains, and hinge pins for elevator doors. In effect, they are useful in any application where severe vibration with shear loading and the need for clamp-up occurs. They prevent accidental separation of components and discourage theft of parts. They may be easily removed for maintenance or repair of parts and are re-usable many more times than clevis and cotter pins. The Quick-Click pin may be specified either for original equipment or to replace clevis pins on a direct size-for-size basis.

The new pins are supplied in either carbon or alloy steel, in sizes from 1 /I 6-in. to 1 -in. diameters. Lengths ordinarily are from l/4-in. to 6 in., but much longer lengths can be furnished. Shear strengths are from 35,000 to 100,000 psi, depending upon the material and heat treatment. Various finishes are available, including thermal oxide black finish and platings such as cadmium and zinc. The Quick-Click pin can be supplied as a double-ended pin with springs on both ends for use where there is insufficient clearance for heads or where it may be desirable to install from two directions.

Unbrako Ltd Circle number 47 on Reader Enquiry Service card

Prevent water condensate from small volume compressed air supplies To users of pneumatic control systems for heating and ventilation of buildings, for air gauging and for general instrumentation comes new from Oxy Fluid Control of Woking, Surrey, of a ‘new look’ for their smallest Deltech compressed air dryer. Small paint spraying installations, laboratory air service and devices with air bearings could also benefit from the dry air provided by this equipment.

The latest Deltech Minidryer Model RFA-04D serves compressed air flows up to 20 scfm at 100 psig (1 Odm3/s at 7 bar) and replaces the two earlier ‘C’ type models covering the same capacity range. Use of a shell case moulded from resin-bonded fibreglass and mounted on a rigid subframe gives strength and durability to a unit of pleasing but functional appearance with an attractive light grey finish which requires no maintenance.

The principle of operation is to cool the warm moisture-laden compressed air coming from the aftercooler to a low temperature by

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simple hermetic refrigeration, thereby precipitating water vapour that would otherwise have condensed throughout the air lines and pneumatic equipment. Better water separation and automatic drainage are further features of the improved Minidryer design which promote reliability in unattended locations.

Overall dimensions of the new dryer cabinet are 20 x 13 x 13 in. (51 x33 x33 cm), inlet and outlet size is 0.5 in. screwed BSP and approximate mounting weight is 70 lb (32 kg).

Oxy Fluid Control Circle number 48 on Reader Enquiry Service card

Australian agent for Thermindex Synthetic 8 Industrial Finishes Limited, of Imperial Way, Watford, have appointed Proco International Pty Limited, 437 St. Kilda Road, Melbourne, Victoria, Australia 3004 (Tel. Melbourne 261725/6) agents in Australia for Thermindex products, including the range of temperature indicating paints and devices.

Synthetic and Industrial Finishes Ltd Circle number 49 on Reader Enquiry Service card

Appointments at Chloride Mr John Ray has been appointed Chairman of Chloride’s Industrial Division. Mr Harry Lymath succeeds Mr Ray as Chairman of Chloride’s Automotive Division. Both Mr Ray and Mr Lymath are members of the Management Board of Chloride Group Ltd - Britain’s largest manufacturer of rechargeable batteries.

Two other important appointments have also been announced by Chloride’s Automotive Division. Mr Kevin Corcoran, managing director of Gaedor Ltd - a Chloride company specialising in the wholesaling of auto-electrical and related components - is to take on the additional role of marketing director for Chloride Automotive Batteries Ltd. This dual role will enable Chloride to co-ordinate more closely the marketing policies of both companies.

Mr Denis Howarth who is currently marketing director of Chloride Automotive Batteries has been appointed managing director of Bardic Systems Ltd. Bardic is one of the fastest growing companies in the Chloride Group and specialises in safety and emergency lighting and security systems.

Chloride Group Ltd Circle number 50 on Reader Enquiry Service card

Electron and ion optics kit Students model EAI 707 is a new kit containing the pieces required to build at least the following : diode electron gun, triode electron gun with electrostatic focusing, Faraday cup. The diode and triode electron gun use many of the same parts so only one or the other of these can be built at the same time. The Faraday cup may be built for use in studying the output of either gun.

In order to use the kit, the buyer should have a small vacuum system (suitable for operation at 1 x 1 O-4 torr or lower) with electrical lead-throughs, power supplies, electrometer, and if possible a small spot welder. The small hand tools required are supplied as part of the kit.

The range of experiments which can be done with the student kit include: (1) Study of filament emission as function of filament temperature (Richardson-Dushman equation). (2) Study of the relation between emission current and electric field (Child’s Law). (3) Construction of a simple diode and demonstration of rectification. (4) Construction of a simple triode. (5) Study of focusing properties of electron guns. (6) Study of properties of