发明名称 |
HEATING RESISTOR FLOW RATE MEASURING INSTRUMENT |
摘要 |
A heating resistor flow rate measuring instrument includes a sub-passage (3) disposed in a main passage (4). A heating resistor (1) and a thermally sensitive resistor (2) are disposed in the sub-passage (3). The sub-passage (3) comprises a first sub-passage having an upstream-side opening face substantially perpendicular to the forward direction of a fluid flow and a downstream-side opening face substantially parallel to the direction opposite to the forward fluid flow, and a second sub-passage having an upstream-side opening face substantially parallel to the forward direction of the fluid flow and a downstream-side opening face substantially perpendicular to the direction opposite to the forward fluid flow. The heating resistor (1) is disposed in the first sub-passage, and the thermally sensitive resistor (2) is disposed in the second sub-passage. The heating resistor (1) is heated to a temperature about 100 DEG C - 300 DEG C higher than a fluid temperature Ta. The thermally sensitive resistor (2) is heated higher than the fluid temperature Ta by about 1/10 to 1/2 of the temperature to which the heating resistor (1) is heated. When the fluid flows in the forward direction, the heating resistor (1) outputs a value depending on the flow rate of the fluid. When the fluid flows in the opposite direction, the thermally sensitive resistor (2) is cooled to a temperature lower than that resulting when the fluid flows in the forward direction, and an electric current flowing through the heating resistor (1) is decreased. As a result, even when a pulsation occurs in the fluid, a precise flow rate can be measured because not only a plus effect caused by a backward flow is eliminated, but also a value corresponding to the backward flow is subtracted. <IMAGE> |
申请公布号 |
EP1396709(A4) |
申请公布日期 |
2006.04.12 |
申请号 |
EP20010941031 |
申请日期 |
2001.06.13 |
申请人 |
HITACHI, LTD.;HITACHI CAR ENGINEERING CO., LTD. |
发明人 |
IGARASHI, S.,;SAITOU, T.,;KIKAWA, H., |
分类号 |
G01F1/684;G01F1/72 |
主分类号 |
G01F1/684 |
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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