Pressure line safety valve - has sprung bypass valve opening opposite to main valve which then requires sufficient back pressure for opening

摘要

The valve consists of a housing with a valve pressed by a spring in the direction of flow against its seat. The valve incorporates a bypass valve which can be operated by hand via a push rod. When the bypass valve is opened, pressure medium can flow from the inlet side via a channel in the valve to the outlet side. The bypass valve is pressed by a spring against its seat and opens in the opposite direction to the main valve in which it is mounted. The main valve body has a hollow stem which protrudes through a seal from the housing and is used to close the valve by hand. The operating rod for the bypass valve passes through this hollow stem. The outlet side of the valve is first pressurised via the bypass valve before the full flow area is opened by the main valve.