GB1049737A - Foam pump system - Google Patents

Abstract

1,049,737. Rotary pumps. CHEMETRON CORPORATION. Aug. 19, 1963 [Aug. 27, 1962], No. 32725/63. Heading F1F. A rotary pump in a foam pumping system for extinguishing fires, comprises a cylindrical casing 23, Fig. 3, eccentrically mounting a rotor 30 having a central boss 34 and spokes 35 forming therebetween hollow spaces 36 to reduce rotor weight and slotted to slidably receive vanes 37a-f, angled as shown (or radial). The casing is surmounted by a manifold 28 having inlet and outlet portions 28a, 28b connected respectively to adjacent pump inlet and outlet passages 25, 26 separated by a wall 27. The inlet portion 28a is connected through a pipe 16, Fig. 1, vented to atmosphere through a predetermined restricted orifice 18 to a valve 15 which proportions the desired amount of water and foam stabilizer from tanks 11, 12 respectively and the outlet portion 28b is connected through a pipe 21 to nozzles 20. In operation, on rotation of the rotor 30 in the direction of the arrow, vacuum is initially created behind the vanes and this vacuum through an operative connection between the pump and the valve 15, opens the valve to supply a water and foam mixture to the pump. A horn-shaped port 51, Fig. 4 (not shown) in one end face of the casing 23 is positioned to suck in air during the intake cycle of the water and foam, and this air is compressed during the discharge cycle of the pump. This is stated to improve the efficiency of the pump, the air requiring less energy to compress than the liquid being introduced when the vanes are in their fully extended position. The air admitted through the orifice 18 in controlled amounts adjusts the initial vacuum in the intake cycle and hence the amount of opening of the valve 15 and the amount of liquid supplied to the pump and consequently the proportion of liquid to air which is varied depending upon the type of fire to be tackled. Instead of air being admitted through the port 51, carbon dioxide, nitrogen, hydrogen or other gases may be used. The pump is driven through reduction gearing. The direction of rotation of the rotor may be reversed, in the case of a rotor with angled vanes this will necessitate the end-to-end reversal of the rotor. The pump may be truck mounted on feet 22.