Pilot operated change-over valve

摘要

A transfer valve according to this invention has an internal pilot channel (15) in communication with a supply port (7); an external pilot channel (16) in communication with an external pilot port (X1); a shuttle valve (25) that selectively guides pilot fluid from the internal (15) and external (16) pilot channels to a pilot valve (3). The shuttle valve (25) has two inlets (25a,25b), one outlet (25c) and a shuttle valve member (29) that always connects the inlet on the high pressure side to the outlet while closing the inlet on the low pressure side, wherein the two inlets (25a,25b) are individually connected to the internal (15) and external (16) pilot channels while the outlet (25c) is connected to the pilot valve (3).