Pressure reducer

摘要

A pressure reducer includes a piston slidably accommodated in a cylinder to define a decompression chamber and a pressure adjusting chamber. A seal member includes an elastic member and a sliding portion. The sliding portion is pressed by the elastic member such that the sliding portion slides on an inner circumferential surface of the cylinder. An annular member is located on an outer circumferential surface of the piston and between the seal member and the pressure adjusting surface. The annular member is pressed against the inner circumferential surface of the cylinder with a force that is less than a force with which the sliding portion is pressed against the inner circumferential surface of the cylinder. Thus, the pressure reducer prevents the piston from being moved by an excessive amount with highly accurately adjusting pressure.

主权项

1. A pressure reducer for reducing a pressure of high-pressure gas flowing in through a first port and sending the gas to a second port, the pressure reducer comprising:
a valve located between the first port and the second port; a cylinder located downstream of the valve; a piston slidably accommodated in the cylinder to define a decompression chamber and a pressure adjusting chamber, wherein the piston has a pressure receiving surface exposed to the decompression chamber and a pressure adjusting surface exposed to the pressure adjusting chamber, wherein gas can flow into the decompression chamber from the first port through the valve, wherein the piston moves in the cylinder according to a difference between a force received by the pressure receiving surface and a force received by the pressure adjusting surface, thereby selectively opening and closing the valve; and a lip seal disposed on an outer circumferential surface of the piston, wherein the lip seal is fitted in an accommodation groove formed in the outer circumferential surface of the piston and is secured to the piston with a fastening nut, wherein the lip seal includes an elastic member and a sliding portion, the sliding portion being pressed by the elastic member such that the sliding portion slides on an inner circumferential surface of the cylinder, wherein an annular member is located on the outer circumferential surface of the piston between the lip seal and the pressure adjusting surface, the annular member sliding on the inner circumferential surface of the cylinder, the annular member having elasticity, wherein the annular member is formed of a rubber or elastomer to include a compressibility as the elasticity in a range from 8% to 15%, such that the annular member prevents the piston from moving abruptly upon a change in a demand for gas, caused when the force received by the pressure receiving surface overcomes a frictional force of the lip seal against the inner circumferential surface of the cylinder, wherein the annular member is compressed by the inner circumferential surface of the cylinder, and wherein the compressibility of the annular member is obtained by dividing an amount of decrease of a thickness of the annular member by a thickness of the annular member before being compressed, such that by a dynamic friction force between the sliding portion and the inner circumferential surface of the cylinder and by a friction force between the annular member and the inner circumferential surface of the cylinder, an abrupt movement of the piston, which takes place due to an abrupt change of the gas pressure at a supplying side of the pressure reducer is prevented.