| 摘要 |
PURPOSE: A filter device related with a valve insert is provided to reduce flow resistance and to facilitate installation and removal. CONSTITUTION: A valve insert(1) comprises a thermostat valve(3) concentrically or serially arranged with a backstop valve(2). The backstop valve comprises a spring-loaded backstop valve piston(4) and a backstop valve housing(5). A guide for the backstop valve piston is formed in one side of the backstop valve housing, and a valve seat is formed in the other side thereof. |
