摘要 |
<p>A safety valve has a housing with an inlet, outlet and a threaded opening carrying a walled unit which is sealingly removable from the housing; the portion of the unit extending into the housing is apertured to permit flow and has a valve seat and co-operating plate to which is attached a valve stem extending through an annular diaphragm in secured relationship. The diaphragm is supported by the housing and in the portion of the unit exterior of the housing is a biasing device which acts on the diaphragm.</p> |