Improvements in or relating to fluid pressure control valves

摘要

985,308. Valves. G. HECKMANN. June 20, 1961 [June 21, 1960], No. 22278/61. Heading F2V. A main spool valve 17 controlling inlet, exhaust, and work ports 26-29, is moved between opposite end positions by the controlled fluid supplied to end chambers 21, 22, the pressures in these chambers being controlled by positioning of an auxiliary piston valve 2 housing a ball valve 4, under the control of an external pilot valve which may be pneumatically, or electromagnetically operated to open and close an outlet control conduit 1 from the auxiliary piston, the arrangement being such that successive opening movements of the control valve result in alternate movements of the main valve from one end position to the other whilst successive closing movements thereof result in positioning of the auxiliary piston alternately in one or the other end position to control the main valve. Pressure fluid is supplied to the end chambers through the interior of the main valve and orifices 15, 16 therein, and the chambers are selectively placed in communication with the control conduit 1 by the auxiliary piston, opposite end chambers of which are selectively placed in communication with the pressure supply or exhaust of the main valve through passages 10, 11 by movement of the main valve. In the position shown, the external control valve is assumed closed. The right-hand end of the auxiliary piston communicates with the pressure supply and the left-hand end with exhaust. Opening of the external control valve results in the main valve moving to the right, thus reversing the connections 10, 11. Ball valve 4 moves to the right past radial ports 7. On re-closing the external control valve pressure builds up on the left of the auxiliary piston moving it to the right in preparation for a reverse movement of the main valve on the next succeeding opening of the external control valve. The main valve may be controlled directly by shut-off valves connected at 30, 31 to the end chambers. In another embodiment, a plain piston auxiliary valve is used, the ball valve 4 being replaced by two ball check valves between the end chambers of the auxiliary piston and the control conduit 1. The device may be used, e.g. in the control of a remote-operated points-adjusting apparatus such as for a travelling train in mining work.