发明名称 |
Thermally-sensitive type flow meter having a high accuracy |
摘要 |
A thermally-sensitive type flow meter measures a flow rate with a high accuracy by eliminating a noise generated in a source voltage. The flow meter includes a sensor chip comprising a substrate carrying sensing elements. First and second resistors are provided on first and second bridges formed over a depression formed on the substrate. The first bridge is positioned on an upstream side and the second bridge is positioned on a downstream side. The first and second resistors generate a heat by the same voltage source. First and second temperature measuring resistors are provided adjacent to the first and second resistors, respectively, to measure a temperature of the first and second resistors. Third and fourth temperature measuring resistors are provided for measuring the temperature of the fluid. A temperature control unit, including the first, second, third and fourth temperature measuring resistors, controls a temperature of each of the first and second resistors to be constant. A flow rate of the fluid is determined based on a voltage difference between a first voltage applied to the first resistor and a second voltage applied to the second resistor.
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申请公布号 |
US5703288(A) |
申请公布日期 |
1997.12.30 |
申请号 |
US19960682162 |
申请日期 |
1996.07.17 |
申请人 |
RICOH COMPANY, LTD.;RICOH ELEMEX CORPORATION;RICOH SEIKI COMPANY, LTD. |
发明人 |
HORIGUCHI, HIROYUKI;NAKAYAMA, YOSHINOBU |
分类号 |
G01F1/68;G01F1/684;G01F1/692;G01F1/698;G01F1/699;G01P5/12;(IPC1-7):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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