The housing of a reduction valve includes an input chamber, an output chamber, and a main valve seat located therebetween which is engaged, when the valve is closed, by a main piston. The interior of the main piston defines a control chamber into which fluid from the input chamber can flow at a limited but substantial rate. An inner valve seat is formed in the top of the main piston which defines an opening leading from the control chamber to the output chamber. An inner piston is adapted to engage the inner valve seat, thus sealing the control chamber against the output chamber when the valve is closed. A lower chamber into which fluid can flow freely from the input chamber is located beneath the control chamber. A vane structure atop the main piston provides an upward force in response to fluid flow across the main valve seat.
The present invention is directed to pulse dampener devices of the type employed to dampen pulses within hydraulic systems such as result from the use of pumps of the piston type. The device includes a pressure vessel having a movable partition therein, dividing the vessel into two chambers, each having a port in communication therewith, respectively a gas port for charging a gas under pressure into one said chamber and an oil port for connection to the hydraulic line. The device is characterized by an improved fitting which is subject to economical manufacture and which provides both the mounting means and the necessary hydraulic connection to the hydraulic system, while at the same time affording improved pulse dampening operation.
In order to improve the balance of fluid forces existing in a balance plug innervalve assembly, a pressure tap is made at the approximate location of the lowest static pressure upstream of the disc seating surface and in close proximity to the vena contracta in order to aspirate the balance piston pressure chamber. This tap allows the lower static pressure to be transmitted to the balance piston by tubing or through a drilled passage in the valve stem to impart a modified piston force that is a closer balance of innervalve force. With this improved force balance, the initial droop is decreased in a self-contained regulator. In a balance piston-type globe valve the actuator size is reduced.
