COLD PACK FOR VANS
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American-type Refrigeration Equipment Offers the Advantages of Ease of Installation and Removal for Servicing
ALTHOUGH the growing carriage by road of frozen foods, ice cream. meat, fish, vegetables, fruit and other perishable goods has expanded the demand for vehicle refrigeration equipment, in general the need for mobile mechanical refrigeration plant has been met, in this country, by the adaptation of conventional stationary apparatus, Now, however, as announced in The Commercial Motor on December 25, 1959, Hawker Siddeley (Hamble), Ltd., Hamble, Southampton, have, under licence from the Thermo King Corporation of America, begun to import a range of mobile refrigeration plant which is specifically designed for vehicle installation.
At present, only assembly is carried out at Hamble from imported components, but it is envisaged that in three months' time 25 per cent. of the components used will be of British origin, rising to 60 per cent, at the end of six months. The intention is to manufacture all the components here eventually.
This should bring about a substantial reduction in cost as freight charges and import duty raise the retail price of the complete unit by about 25 per cent, at the moment.
According to Mann Egerton and Co.. Ltd., who are one of the five distributors appointed for the Thermo King equipment and were the first to fit it to an insulated semi-trailer van in this country. it is only half the size of normal refrigeration plant required to do the same job.
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The Thermo King equipment takes up little body space, as the power unit, compressor, condenser coils and controls are fitted in a box which is mounted on top of the cab on rigid vehicles and to the front of the body on semi-trailers. The rear section, which protrudes into the body. contains the cooling coils, circulating fan and the automatic control valve. Longitudinal ducting may be fitted at the top of the body to ensure correct
dispersal of the cold-air output from the unit.
The eight basic models offered by Hawker Siddeley employ the same compression principle of refrigeration with forced convection. Warm air is drawn from the body, passed over the cooling coils and blown back into the top of the cooled space. The types available provide cooling down to below 0°E. for vehicles ranging from small vans to the largest semi-trailers likely to be operated in Britain. or in the countries overseas to which Hawker Siddeley will export the Thermo King equipment.
Each unit is offered with a choice of three power units or any combination of them. The compressor can be driven by a petrol engine, an electric motor or a hydraulic motor receiving its oil supply frcrm a pump connected to either a gearbox power take-off or V-belts on a crankshaft pulley.
VV1i.en a vehicle is to be used for multistop delivery work, a petrol engine would normally be employed to give a constant degree of refrigeration, although hydraulically driven versions are being used for this work with some success. The disadvantage of the hydraulic system is that cooling can take place only while the main engine is running.
In most installations, the petrol engine or hydraulic motor is supplemented by an electric motor which can be used for pre-cooling or to maintain refrigeration overnight when the vehicle is off the road.
With either, the petrol engine or electric motor, control of the unit is automatic once the .desired body temperature has been set and the unit started. A temperature-sensing device starts and stops the motor to maintain the thermostat setting. A gauge indicating the internal body temperature is normally placed where it can be seen .from the, cab to warn the driver of malfunctioning: Automatic Defrosting Regular defrosting of the cooling coil is essential, and this is carried out automatically by a solenoid every four hours. This closes a shutter to cut off the cooling air supply and causes hot refrigerant gas (Freon) to be fed through the cooling coils. A manual control may replace or augment this if required.
As the Thermo King equipment is produced as a unit, it is easy to fit to a vehicle and equally simple to remove for servicing. Both Sparshatts (Metal Bodies), Ltd., Southampton, and C. L. Whitaker and Co., Ltd., Grimsby, who are Thermo King distributors and have already fitted the equipment to vehicles. support this claim.
Hawker Siddeley will offer also for buses an air-conditioning system employing the same principle as the refrigeration plant. As this unit costs over £1,500 it is unlikely that it will prove popular in this country, but might be a boon for the Middle East and Commonwealth countries to which it could be exported.