DISPOSITIF D'ALIMENTATION EN FLUIDE D'UNE INSTALLATION HYDRAULIQUE, PNEUMATIQUE OU HYDRO-PNEUMATIQUE

摘要

A flow-control valve has a valve housing defining a chamber formed with axially offset source, sump, and user ports. A valve body in the chamber has first and second coaxial but axially independently movable parts, the first part having a mainly axial throughgoing passage having one end exposed continuously to one of the source and sump ports and an opposite axially open end axially sealingly engageable with the second valve part. A central seat between the source and sump ports is axially sealingly engageable with one of the valve parts to isolate one of the source and sump ports from the other of the source and sump ports. The parts are displaceable between one end position permitting flow in the chamber between the user and the other port while blocking flow between same and the one port with the valve parts in sealing engagement with each other and the one valve part out of engagement with the central seat, an intermediate position blocking flow in the chamber between the ports with the valve parts in sealing engagement with each other with the one valve part in sealing engagement with the central seat, and a drain end position permitting flow in the chamber between the user and one port while blocking flow between same and the other port.