GB699029A - Improvements relating to vehicles for the bulk transport of liquids - Google Patents

Abstract

699,029. Liquid transport vehicles. SHELL REFINING & MARKETING CO., Ltd. Feb. 4, 1952 [Jan. 8, 1951], No. 561/51. Class 21 [Also in Groups XXVI, XXVIII and XXIX] A pump for emptying the tank of e.g. a petrol lorry, motivated by a supply of compressed air carried by the lorry, comprises two liquid chambers 4, Fig..3, separated from air chambers 3 by two mechanically connected diaphragms 5 whereby the liquid chambers are emptied alternately by the movement of the diaphragms, and an attached valve member 8, driven by the compressed air. The liquid chambers 4 have an inlet port 6a and outlet port 6b. The diaphragms 5 are attached centrally to a rod 7 sliding in the valve member 8, which itself can move axially in a fixed chamber 9 comprising a centre sleeve having two ports 11 registering with a recess 36 in the housing to which is attached the compressed air feed pipe 13, and two pairs of ports 12a, 12b registering with the air chambers 3 alternately through ducts 37 in the casing 2. The chamber 9 also has a central port registering with an air outlet duct in the housing which is not visible in this view. Operation of pump. In the extreme right-hand position of the diaphragms 5, the left hand ports 11, 12a intercommunicate via the interior of valve chamber 9 to drive left-hand diaphragm 5 to the left. Right-hand port 12b is open to atmosphere via a recess 16 and the central port, whereby the pressure in chamber 3 is released. As the left-hand diaphragm 5 moves to the left it causes the righthand diaphragm to perform its suction stroke via rod 7. Near the end of its stroke, right-hand diaphragm 5 strikes the end face of valve member 8 and moves it through the central position, seen in Fig. 3, when the pressure input and output connections are interchanged, so that when the diaphragms reach the end of the stroke, the right-hand diaphragm 5 is under full pressure to reverse the stroke, the valve member 8 staying in its position until the left-hand diaphragm 5 moves it to the right. A delivery nozzle, Fig. 6, connected to the hose by a swivel connection 29, comprises a valve member 23 held by a spring 24 against a central valve seat 21. The front end 26 of the valve member 23, shrouded by a flexible, electrically conductive cap 27, is pressed into the filling orifice of the tank to be filled, when valve member 23 is forced backwards to open the valve. On closing the valve, the back pressure of the liquid stalls the pump.