To obtain differential pressure measured values without output errors or internal pressure differences between filler liquids even with the presence of temperature differences between the high-pressure measurement side and low-pressure measurement side of a fluid to be measured by providing high pressure-side and low pressure-side filler liquid compensating chambers and high pressure-side and low pressure-side capillary tubes.
A high pressure-side filler liquid compensating chamber 21 is provided for the main body block 72 of a high pressure-side diaphragm seal unit 7 and filled with a filler liquid 8 to compensate temperature differences in the high pressure-side diaphragm seal unit 7. A low pressure-side filler liquid compensating chamber 23 is provided for the main body block 112 of a low pressure-side diaphragm seal unit 11 and is filled with a filler liquid 12 to compensate errors. One ends of low pressure-side and high pressure-side compensating capillary tubes 22 and 24 are connected to the low pressure side and high pressure side of a differential pressure measuring device 1. Their middle parts are in parallel with high pressure-side and low pressure-side capillary tubes 6 and 9. The other ends are connected to the high pressure side and low pressure-side filler liquid compensating chambers 21 and 23. Both compensating capillary tubes 22 and 24 are filled with the filler liquids 8 and 12 to compensate errors in the high pressure-side and low pressure-side capillary tubes 6 and 9.
TAKAHASHI HIROYASU
ITO AKIHIKO
MARUYAMA AKIHIKO
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