GB293325A - 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

293,325. British Celanese, Ltd., and Kinsella, E. Dec. 23, 1926. Pumps, regulating delivery of by throttle and stop valves.--Apparatus for supplying regulated quantities of artificial silk spinning solution or other liquid to a spinning jet or jets or other points of use, comprises a source of liquid supply under pressure, which source is conveniently a pump, one or more measuring pumps particularly of the gear-wheel type, and one or more control units corresponding with the measuring pumps, each control unit being provided with a valve member actuated differentially by the pressure on the inlet and delivery sides of its measuring pump, the valve controlling a port through which liquid is supplied to the measuring pump, all in such a manner as to maintain substantially equal the pressures on the inlet and delivery sides of the measuring pump. The control unit may be so arranged as to provide a relief for any excess out-of-balance pressure that may develop on either side of its measuring pump. As shown in Fig. 1, a main header 1, a control unit 3, and a measuring pump 2 are so conected that liquid under pressure drawn from the header passes to the control unit, thence to the measuring pump, then returns to the control unit, being finally delivered to the spinning jet or other point of use. The control unit comprises a piston 5 constituting a partition between the chambers 7, 8 connected to the inlet and delivery sides of the measuring pump 2; a hollow member 6 carried by the piston 5 acts as a piston valve controlling the supply of solution from a groove 11 in communication with the main header; solution passes through a port or ports 14 into the interior of the member 6, and from thence through apertures 15 into the space 7 from which the measuring pump draws liquid. In normal operation, the ports 14 are opposite the groove 11; when an excess pressure is developed on the delivery side of the pump, the control member rises, closing the ports 14 and eventually exposing a relief passage 18 conveniently closed by a diaphragm of easilyruptured material. A by-pass passage 20 adapted to be closed by a screw 21 permits of the supply of solution when initially starting the apparatus. In other forms of control unit, the piston 5 is replaced by a diaphragm, and the piston control valve is substituted by a double conical valve 6, as shown, for instance, in Fig. 1<A>; the spring 19 used to assist the return of the control member against the delivery pressure is omitted; and the measuring pump is mounted directly on its control unit. Alternative constructions of devices for dealing with excess pressures that may be developed are shown in Figs. 1<A>, 2<A> and 3<A>. These consist essentially of an auxiliary piston 12 exposed on its two sides to the inlet and delivery pressures existing in the chambers 7, 8 of the control unit. The auxiliary piston 12 carries a piston valve 13 which under normal conditions covers the relierf passage 19. The form shown in Fig. 1<A> deals with excess delivery pressures only, and in this form the piston 12 is supported by a stem 17 against the action of a spring 18; the modification shown in Fig. 2<A> can function as a relief device in respect of excess inlet pressures and excess delivery pressures, the construction differing from the simpler device in that the stem of the piston 12 is shortened and that the latter is held poised between opposing springs 17a, 18. An excess delivery pressure by raising the piston 12 and its piston valve 13 uncovers the relief passage 19 which is then put in communication with the inlet side of the pump through the passage 14 and open channel 15 ; similarly an excess pressure on the inlet side of the pump causes the piston to move downwards, again uncovering the relief passage 19 and permitting liquid to escape from the inlet side of the pump as before. The source of liquid supply under pressure is conveniently a gear-wheel pump; and the delivery pressure is maintained substantially constant by the provision on the inlet side of the pump of a throttling-valve 14, Fig. 3, carried by a piston 13 which is itself exposed to the delivery pressure; and there may also be used a bye-passing valve 15a, Fig. 3<B> exposed to the delivery pressure and controlling a bye-pass 17, the bye-passing valve compensating any sluggish action of the throttling- valve.