Diaphragm breakage condition detecting device for a pressure control device

Claim 1

A diaphragm breakage condition detecting device for a pressure control device comprising: (a) a casing (62), (b) a diaphragm member (64) pertitioning the casing (62) into a first chamber (66) and a second chamber (68), said second chamber (68) having an opening (68a) exposed to air, (c) a compression spring (78) interposed between the diaphragm member (64) and the inner wall of said casing (62) within said second chamber (68). (d) an actuating rod (70) one end of which is supported by said diaphragm member (64), while the other end thereof extends towards exterior of said casing (62) through said opening (68a), (e) a breakage detecting switch (72) supported by a displaceable partitioning member (74) which is at the bottom portion thereof mounted on an inner wall of said second chamber (68), which is opposite to said diaphragm member (64), (f) a third chamber (76) defined by said displaceable partitioning member (74) and the inner wall of said casing (62), (g) a control vacuum P 1 supplied into said first and third chambers (66, 76), whereby, if there occurs breakage in said diaphragm member 64, said breakage detecting switch (72) mounted on said displaceable partitioning member (74) moves towards said diaphragm member (64) to become in contact with the one end of said actuating rod (70), thereby to become operative to detect the breakage in said diaphragm member (64).