CARRYING 3,300 GALLONS IN ONE VEHICLE.
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Details of the Latest Scammell Tractor-trailer Tank Wagon in Which the Tank Constitutes the Frame of the Trailer Portion.
APARTICULARLY interesting type of vehicle which presents considerable potentialities has just been completed. by Scammeil Lorries, Ltd., 14-18, Holborn, London, E.C.1. This is--a 3,300.? gallon tractor-tthiler tank wagon built for Shell-Mex, Ltd:, to carry Alex fuel oil, The chief feature about the vehicle is that the tank also forms theframe of the trailer portion, for which purpose the brackets for the turntable and for the rear springs are bolted direct to the tank .
The size of the tank is 19 ft, 6 ins. by 5 ft. 10 ins., and it is provided with cross stiffeners to take any local stresses which
might occur as a result of the disposition of the load or road shock. These stiffeners also act as awash plates in order to pre-vent, surging of the oil. • There is a special pad under the tank, towards the front end, which is used as a rest for the head of the jack while the vehicle. is being connected to, or disconnected from, the tractor portion, This pad is made of steel and packed with hard wood.
To provide additional strength to the tank, double plates are fitted wherever important parts are bolted. .
The bottom plate of the tank is in one piece running the whole length, i.e., 19 ft. 6 ins., and having a-width of approximately 6 ft.
The arrangement of Jim turntable is somewhat novel, as the upper half of it is a standard lower half reversed, and seating against another lower half in the ordinary position.
The spring brackets are Of cast steel and are bolted right through the tank, the bolts being driven into position in order to avoid the risk of leakage 'The brackets for the brake sliding compensator are also bolted direct to the tank. This construction enableS a saving in weight of 15 cwt., arid, consequently, the vehicle may carry 12 tons of oil. Mounted on the cross-member in front of the radiator is a three.cylinder radial air compressor. which_ can also be converted into an air exhausting pump. This pump works at is normal speed of 600 r.p.rit, although it, has been run at considerably higher speeds than this for long periods without injury.
It is connected to the front end of the crankshaft by an Oldham coupling, and is engaged or disengaged by a lever at the near side of the engine. This air pump works practically silently and without vibration. Each-cylinder has a separate 'piston valve, the valves being operated by eccentrics, and the. lubricant pressure fed.
In order to fill the tank, the air is exhausted and the fuel takes its place. For discharging the oil the air pump is kept in action and a pressure of 20 lb. to 30 lb. is attained. This allows the oil to be forced out rapidly under the control of a large valve at the rear end of the tank. If necessary, 40 113 pressure can easily be attained, but this would seldom be required.
Quite apart from its,„use as an oil car .]ter, the new vehicle has great possibilities for the cariying of large quantities of water or other liquids. It should prove specially suitable for street 'watering in provincial towns, where the main water is scarce, as the vehicle could he driven to the dearest large source of supply, and it could then be kept in use for a considerable -period oh the one tank of water. With a 6-in. hose it can be filled in a few minutes. For watering purposes a great advantage is that the pressure does not vary with the speed. It can easily be kept constant by altering the position at which the relief valve open.s.
For special purposes, such as providing water for troops, the vehicle might also prove of great utility, as it Can if necessary, carry 15 tons of water, although such a quantity would bring its total weight above the legal limit, so that it could only be used with its full load in cases a special urgency:
As will be seen from our illustrations, the whole tank slopes to the rear, and this alone provides a small head of water. A base box is fitted along each side above the wing brackets.