Patent ID: 6662819
Filing Date: 2003-12-16
Classification: F17C,Y10T

Abstract:
A valve for automatic switchover from a plurality of pressure sources to a common outlet in response to failing or failure of said source, said valve comprising:a valve body having first and second inlet ports for connecting to said pressure sources and a common outlet; a valve body having an internal bore communicating with said first inlet, said second inlet, and said outlet; a valve member in the form of a spool, moveable in said bore between a first position where fluid pressure is communicated with said first inlet and said outlet and blocking said second inlet, and a second position where fluid pressure is communicated with said second inlet and said outlet and blocking said first inlet; said spool with means of communicating with each said inlet and first and second piston effect chambers in said valve bore; said spool being subject to fluid pressure supplied to said first inlet for moving it to the first mentioned position and to fluid pressure supplied to said second inlet for moving it to the second mentioned position; springs positioned on either end of said spool, biased axially against said piston effect of said spool; pressure force of said piston effect set against said spring bias whereas minimum source pressure is overcome by said spring; a gap configured between said spool and said spring to allow unencumbered movement of said spool upon depletion of said piston effect pressure in said chamber.