Damping valve for pressure regulator

A pressure regulator operative responsive to inlet pressure and outlet pressure comprising:

• a. a housing having an inlet, an outlet, a transverse wall separating the inlet and the outlet, and an outlet chamber formed on the outlet side of the transverse wall,
• b. a valve diaphragm disposed on the outlet side of the transverse wall and having one side thereof in communication with the outlet chamber,
• c. an inlet orifice formed in the transverse wall to communicate the inlet with the outlet,
• d. a valve connected to be actuated by the valve diaphragm and to be shifted toward or away from the inlet orifice responsive to the pressure in the outlet chamber,
• e. a damping chamber formed in the housing below the valve, said damping chamber having a circular cross section,
• f. hydraulic liquid filling the damping chamber,
• g. a flexible seal, having a central aperture, to separate the outlet chamber from the damping chamber,
• h. a piston, having a head, slidingly received in the damping chamber, said head of the piston being circular and of substantially equal diameter to the cross section of the damping chamber, a lower portion being formed on the piston below the head and of reduced diameter, and a spring is received about the lower portion and to engage the bottom of the chamber to normally urge the piston upwardly in the direction of the seal.
• i. a plurality of flats formed on the head in circumferentially spaced relationship to each other to provide passages for the hydraulic liquid to pass from one side of the piston to the other whenever the piston is moved,
• j. a connecting rod sealingly passing through the flexible seal, and having one end located in the valve and the other end affixed to the piston, and
• k. said housing having a portion opposite the inlet orifice which is counterbored to define a large upper bore and a small lower bore, with the lower bore forming said damping chamber, the flexible seal being circular and fitted within the upper bore, and a retaining ring clamps the flexible seal to the bottom of the upper bore to enclose the top of the damping chamber.