To suppress a change in zero point of an overload protecting diaphragm especially due to high pressure and a change in zero point due to deformation of a pressure receiving member.
Chambers 17, 18 for receiving pressure of measured fluid are formed of a seal diaphragm attaching hole of a single pressure receiving member 20 and plugs 32, 35, 36, and seal diaphragms 6, 7 are attached in parallel to both ends of the pressure receiving member. An overload protecting diaphragm 4 and a sensor assembly 2 are provided in a perpendicular direction to the seal diaphragms 6, 7, a first pressure receiving chamber 201, a first isolation chamber 203 and a semiconductor differential pressure sensor are conductive via conductive paths, and similarly, a second pressure receiving chamber 202, a second isolation chamber 204 and the semiconductor differential pressure sensor are conductive via conductive paths. In order to suppress deformation of the second isolation chamber, a sealing member of the second isolation chamber is made into a double structure comprising first and second fixing jigs 8, 28, and a third isolation chamber 206 is provided between them to lead a pressure of the same fluid to be measured as the second isolation chamber.
HIDA TOMOYUKI
ISHIHARA TAMIO
