PURPOSE: To detect an accurate value even when excessive pressure is applied from a process fluid by providing a differential pressure transmitter so that the pressure receiving direction of a center diaphragme is different from the pressure receiving direction of first and second seal diaphragms.
CONSTITUTION: When the pressure from a process fluid is applied to a seal diaphragm 6, pressure is transmitted to a semiconductor differential pressure sensor 44 from the seal liquid 15 of a pressure receiving chamber 201 and the isolated chamber 203 between an overload protecting diaphragm 4 and a center metal fitting. Even when pressure is applied to a seal diaphragm 7, in the same way, the pressure is transmitted to the rear surface of the sensor 44 from the seal liquid 16 of a pressure receiving chamber 202 and an insolated chamber 204. Since the diaphragm 4 is arranged in the direction right-angled to the diaphragms 6, 7, even when excessive pressure is applied to measuring fluid pressure receiving chambers 17, 18, the strain of a member generated in the vicinity of the diaphragms 6, 7 becomes hard to transmit to the diaphragm 4 and, therefore, the change of the zero point of the diaphragm or the change of a motion fulcrum is eliminated and accurate differential pressure can be measured.
| JPS6042351 | [Title of the device] Pressure gauge |
| WO/1988/009921 | MODULAR TRANSMITTER |
| JPH04120350 | [Title of the device] Differential pressure detecting device |
NAGASU AKIRA
TAJIRI YOJI
YAMAMOTO YOSHIKI
