GB1360405A - Automatic drainage of liquid from pressurised gas systems - Google Patents

Abstract

1360405 Fluid-pressure servomotor systems JOY Mfg CO 2 Nov 1971 50940/71 Heading G3P [Also in Division F1] In compressed gas, steam or distillation systems wherein collected condensate 11 has to be drained through a passage 13, 17, 22, 25 with the minimum loss of the gaseous fluid above the condensate, a periodically opened drain valve 14 is closed in response to the change in pressure which occurs in a chamber 21 when gas instead of condensate flows therethrough. The pressure change occurs in the chamber 21 as a result of restricted orifices 18, 19 disposed, respectively, in the inlet and outlet lines 17, 22 of the chamber 21, the orifice 19 being of equal or greater area than the orifice 18. In the embodiment shown the valve 14 is fluid controlled but it may be controlled by an electric circuit, Figs. 3 and 6 (not shown) which circuit includes a pressure switch operable when pressure rises in the chamber 21. Periodic opening of the valve 14 is caused by a timer which moves a valve 30 to a position connecting a pressure source 32 to a line 28, 24 thereby to act on a diaphragm 16 and open the valve 14. When pressure rises in the chamber 21 due to the commencement of gas flow, this pressure acting through a line 23 lifts a spool 27, Fig. 2, against the bias of a spring 37. The line 24 is therefore exhausted through a passageway 42 whereby the valve 14 closes. The lifting of the spool 27 also causes pressurization of a chamber 36 via a spool passage 38 and a branch pressure line 28' so that the spool is held in its lifted position. Hence, when the pressure falls in the chamber 21 because of the closure of the valve 14, the spool remains lifted until the timer returns the valve 30 to its original position. A system for draining condensate from between the stages of a four-stage compressor is described, the system utilizing a single chamber 21 for controlling the drain valves of a pair of drain lines.