Valve devices for use in measuring or controlling gas-pressure.

摘要

A valve device enabling gas-pressure above a predetermined value to be readily detected comprises a valve member (31) urged by a spring (29) onto a seat (13). Pressurized gas entering by way of a restriction (7) forces the valve open and escapes by way of a whistle formation (34,35). The device may be adjustable for different pressures, and to this end the spring-loading can be varied by rotation of a tube (16) connected to the valve body (2) by a screw-formation (9). The pressure-setting is indicated by a scale (20) on the tube and an index (21) on the body. Initial adjustment can be effected in the factory by a screw (27). Subsequent access to the screw is then prevented by the application of a snap-on cap (33). An adjustable pressure-relief valve is similar in construction but lacks the whistle-formation.