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Title:
DIFFERENTIAL PRESSURE MEASURING DEVICE
Document Type and Number:
Japanese Patent JP3180512
Kind Code:
B2
Abstract:

PURPOSE: To enable self-diagnosis of the leakage of sealed liquid by comparing the 0 points obtained by making the pressures on the high pressure side and low pressure side during self-diagnosis equal to a measuring pressure and the atmospheric pressure, respectively with the characteristic value at the initial 0 point.
CONSTITUTION: In normal measurement, if pressure acts from the higher pressure side, the pressure is transmitted to a silicon diaphragm by sealed liquid A and on the contrary, if pressure acts from the lower pressure side, the pressure is transmitted to a silicon diaphragm by sealed liquid B. Therefore, in accordance with the pressure difference between the high pressure side and the low pressure side, the silicon diaphragm is distorted and from this distortion, the differential pressure is measured. During self-diagnosis, the 0 point measured under the condition that the pressures on the high pressure side and low pressure side of the device are equalized to the measuring pressure, and the 0 point measured under the condition that the pressures on the high pressure side and low pressure side are equalized to the atmospheric pressure are compared by a CPU 22 with the characteristic value at the initial 0 point stored in a memory 21. If the difference is larger than a predetermined value, the leakage of the sealed liquid A or B is judged.


Inventors:
Saichiro Morita
Akira Fujita
Application Number:
JP15205993A
Publication Date:
June 25, 2001
Filing Date:
June 23, 1993
Export Citation:
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Assignee:
Yokogawa Electric Corporation
International Classes:
G01L13/02; G01L9/00; G01L27/00; (IPC1-7): G01L13/02; G01L27/00
Domestic Patent References:
JP636431A
JP2213736A