초록 ▼

A hydraulic piloted pressure reducing and regulating valve which is fail safe for holding the valve at the last selected operating pressure in the event of the loss of control signals. A pressure regulating valve having a body and a control piston therein is provided with a pilot piston in the body

A hydraulic piloted pressure reducing and regulating valve which is fail safe for holding the valve at the last selected operating pressure in the event of the loss of control signals. A pressure regulating valve having a body and a control piston therein is provided with a pilot piston in the body which is adapted to be connected to a hydraulic pilot pressure. A spring is provided between the pilot piston and the control piston whereby the control piston can move in response to flow demands in the valve. A rod is connected to the pilot piston with a locking sleeve engaging the rod and releasably locking the rod and pilot piston against movement. A hydraulic pressure port is in communication with the space between the rod and the sleeve for releasing the rod upon application of pressure to the port. The port and the pilot piston are separately connected to a hydraulic fluid supply and a control system whereby upon failure the valve will maintain the last selected operating pressure.

대표청구항 ▼

In a hydraulic pilot pressure reducing and regulating valve having a body and a control piston therein, the improvement of a fail safe means for holding the valve at the last selected operating pressure in the event of loss of control signals comprising, a pilot piston in said body and adapted to be

In a hydraulic pilot pressure reducing and regulating valve having a body and a control piston therein, the improvement of a fail safe means for holding the valve at the last selected operating pressure in the event of loss of control signals comprising, a pilot piston in said body and adapted to be connected to hydraulic pilot pressure, spring means between the pilot piston and the control piston whereby the valve is regulated in response to hydraulic pilot pressure, a rod connected to the pilot piston, a locking sleeve normally gripping the rod and releasably locking the rod and pilot piston against movement, a hydraulic pressure port in communication with the space between the rod and the sleeve for releasing the rod from the sleeve upon application of pressure to said port, said port and said pilot piston separately connected to a hydraulic supply and a control system, and said control system including means for controlling the application of the hydraulic supply to said port and said piston, said means connecting the hydraulic supply to the port for releasing the locking sleeve when the hydraulic supply to the piston is changing, but venting the hydraulic supply to its port when hydraulic supply to the piston is static thereby allowing the locking sleeve to lock for maintaining the valve in its last selected operating pressure.