发明名称 |
Thermal flow meter, thermal flow meter control method, and sensor element of thermal flow meter |
摘要 |
A thermal flow meter corrects flow rate detection errors produced by vaporization of liquid phase components included in a gas to be measured. The thermal flow meter includes a correction circuit 500 that applies respectively different predetermined voltages to heating resistors consisting of first heating resistor Rh1 and second heating resistor Rh2 of a sensor element disposed in the gas to be measured to set a first temperature state and a second temperature state, calculates a first flow rate value Q1 of the gas to be measured in the first temperature state and a second flow rate value Q2 of the gas to be measured in the second temperature state, and calculates a flow rate correction valueΔQ based on a ratio (Q1/Q2) between the first flow rate value and second flow rate value or a fourth-power value (Q1/Q2)4 of the ratio to correct a flow rate of the gas to be measured. |
申请公布号 |
US7814785(B2) |
申请公布日期 |
2010.10.19 |
申请号 |
US20080242347 |
申请日期 |
2008.09.30 |
申请人 |
HITACHI, LTD. |
发明人 |
SUKEGAWA YOSHIHIRO;TOKUYASU NOBORU;HOSHIKA HIROAKI;KASHIO KAORI |
分类号 |
G01F1/68 |
主分类号 |
G01F1/68 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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