Improved device for supplying a liquid at a definite and constant rate for use in the manufacture of artificial silk and allied materials

摘要

In a system for the continuous supply of a liquid at a definite and constant rate, by means of a measuring pump, to an artificial silk spinning solution flowing under pressure to spinning nozzles or other extrusion devices, in which system a supply pump having a larger output than the measuring pump is provided in the feed line to the measuring pump and the line connecting the discharge side of the supply pump to the suction side of the measuring pump is connected by means of a return line with the feed line to the supply pump, part of this return line consists of a pipe, the walls of which are flexible and resilient, e.g. a flexible rubber tube, and which is located in a closed vessel either forming a part of the discharge line of the measuring pump or being in communication therewith so that increases or decreases in the pressure in the discharge line of the measuring pump will effect corresponding increases or decreases in the pressure in the return line and consequently in the feed line of the measuring pump. As shown, the liquid to be added to the spinning solution is fed from the storage tank 2 via the feed line 31, three-way cock 9, the feed lines 32, 33, the gear wheel supply pump 5 and the feed lines 34 and 35 to the gear wheel measuring pump 4, the capacity of which is only a fraction (e.g. one-tenth) that of the pump 5. The excess of liquid delivered by the pump 5 flows via the return lines 61, 62 and 63 back into the supply pump feed lines 32, 33 and only a minor proportion of the liquid supplied by the pump 5 is fed to the spinning line 1 via the feed lines 36, 37, 38, the chamber 8 and the non-return valve 13. The pressure in the chamber 8, which is equal to the pressure in the delivery line of the pump 4, presses together the walls of the return line 62, which consists of a rubber tube, as a result of which the pressure in the return line 61 and feed lines 34 and 35 is increased. In th state of equilibrium the pressure in the rubber tube 62 is almost equal to that in the chamber 8, so that the pressures at the inlet and discharge sides of the pump 4, as indicated by pressure gauges 14 and 15, are practically the same, and the output of the pump is therefore constant for a given pump r.p.m. and unaffected by any variations in the pressure of the liquid in the pipe 38. The output of pump 4 may be measured as follows. The three-way cock 9 is turned to fill the measuring vessel 11 with liquid from the feed tank 2. This filling may be allowed to take place without interruption of the supply of liquid to the spinning solution. The vessel 12 is then filled with a second liquid of lower specific gravity than the first liquid, e.g. a colourless mineral oil, as an indication liquid. The cock 9 is then turned so that the line 32 is in communication with the measuring vessel 11 only and the time then required to discharge the first liquid from the vessel 11 is then observed. A non-return valve 13 may be provided at the junction of the liquid supply line 39 with the spinning line 1. The liquid supplied to the spinning solution may contain a dye and/or pigment in order that the spun threads may be coloured and/or delustred.