DIAPHRAGM TYPE CONTROL VALVE DEVICE

摘要

Disclosed is a diaphragm apparatus comprising a first chamber and a second chamber which are separated by a diaphragm. The diaphragm has on its peripheral portion an annular raised portion projecting into the first chamber. A part of the casing defining the second chamber is arranged so as to abut against the recessed rear surface of the annular raised portion for preventing the annular raised portion from being flexed in the reverse direction when the vacuum level in the second chamber becomes greater than that in the first chamber.