New L.P.G. Carriers for Shell
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THE first two vehicles to he built for the bulk carriage of liquefied petroleum gas in this country have been put into service by Shell-Mex and B.P., Ltd.
Hitherto L.P.G. has been carried in relatively small metal cylinders, but the new vehicles have a capacity of 1,800 gallons and are fitted with pumping and metering equipment. They have been built for use in South Wales, and are operated from the Llandarcy refinery, one of the present delivery runs being to the plant of Britsh Geon, Ltd., at Barry.
The L.P.G. tanks were supplied by Whessoe, Ltd., Darlington, and have a gross water capacity of 2,044 gallons. They are 15 ft. long over the dished ends and have an inside diameter of 5 ft. 6 in. The barrel plates are 15/32 in. thick and the end plates are 21/32 in. thick, the working pressure being 210 p.s.i. The liquid is carried at a20 approximately 125 p.s.i., this pressure varying slightly according to the atmospheric temperature.
A.E.C. Monarch four-wheeled chassis with 7.7-litre oil engines and four-speed gearboxes are used. Michelin D20 metallic tyres are fitted and the gross running weight is approximately 13 tons, the taxation weight being 8 tons 21 cwt.
A Bayhams 6-in. R. and G. float-type contents gauge is fitted, ' it being impossible to dip the contents of an L.P.G. tank, and the Bayhams gauge is supplemented by two Rego fixed-tube gauges to provide a further check. The discharge rate is 40 gallons per minute.
Lockheed-Avery propane wet hose couplings are used with the filling hose, the inlet connection being in the rear of the tank. A vapour-return fitting is also provided to hold the initial pressure In the lowest level and to correspond with the supply-tank pressure.
The delivery system includes a Shand and Jurs hydraulically operated footvalve, a Rego excess-flow valve, and a Varley SH.75 propane pump, driven from the gearbox power take-off. An Audco HX.154 four-way change-over valve is used and the outflow is diverted to a Brodie B.53 meter. The hose is diameter Lockheed Avery type 7 (fire resistant), And is 30 ft. long.
When the tank is empty the Brodie meter automatically ceases the delivery, closure of the hose end check valve being assured by the inability of the pump to develop sufficient pressure (by reason of the bleed return to the tank) to offset the spring load. After complete discharge, the delivery hose and the .meter arc left " wet." The hose racks are arranged so that the stowed hose falls away to the meter and delivery valve, thus permitting the 'liquid remaining in the hose to be returned to the tank.