GB311670A - Improvements in or relating to apparatus for use in the manufacture of artificial silk or other operations in which liquids are supplied under pressure - Google Patents

Abstract

311,670. British Celanese, Ltd., and Kinsella, E. Feb. 9, 1928. Regulating delivery by by-passes. -Pumping apparatus for delivering regulated quantities of spinning solution or other liquid to the spinning nozzles of an artificial silk &c. plant, comprises a static measuring-device a rotary or other pump delivering liquid under pressure to the static measuring-device, and a pressure - balance valve actuated differentially by the inlet and delivery pressures of the static measuring-device and arranged to control a by-pass connecting the inlet and delivery sides of the pump so as to maintain a constant difference of pressure between the inlet and delivery pressures of the static measuring-device. The static measuring-device may be adapted to maintain constant the supply of liquid therethrough under variations of temperature. The pressure-balance valve may be so constructed, or means may be provided in association therewith, that should excess pressure develop on either side of the static measuring-device, the inlet and delivery sides of the pump are put freely into communication. As shown in Figs. 2, 3 and 4 the static measuring-device 4 consists of an orifice 19 in a plate 18, and the pressure-balance valve comprises a piston 6 working in a chamber 9 against a spring 23 and a hollow piston valve 7 mounted on the piston 6 and provided with a notch or notches 14 serving to control the passage of liquid to a groove 15 in communication with the inlet -side of the pump 2 ; the notch 14 and groove 15 form part of a by-pass connecting the inlet and delivery sides of the pump, and other parts being the chamber 8, apertures 13 and the hollow stem of the piston valve 7. By suitable proportioning of the parts and by the provision of recesses 28, Fig. 3, in the walls of the piston chamber 9, excess pressure developed on the delivery side causes the piston valve to rise uncovering the groove 15 so that the inlet and delivery sides of the pump are put into free communication, while further movement of the piston permits the execss pressure on its underside to be relieved through the recesses 28, which now are uncovered; a spring 32 serves to return the valve to its normal position. Under excess pressure on the inlet side, the piston 6 is forced downwards and the upper edge of the valve 7 uncovers the groove 15, the pump then working idly. Alternative means for dealing with excess pressures are shown in Fig. 4, and comprise an auxiliary piston 33 poised between springs 42, 43 while being subjected to the inlet and delivery pressures of the static measuring-device. Piston valves 35, 36 on the auxiliary piston control passages connected through a pipe 40 with the inlet side of the pump. In the place of the piston valve 7, a needle valve 10, Fig. 7, may be employed; and the piston 6 may be substituted by a spring-loaded diaphragm 5, Fig. 7.