Mass flow rate controller |
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| 申请号 | JP30718889 | 申请日 | 1989-11-27 | 公开(公告)号 | JPH03166611A | 公开(公告)日 | 1991-07-18 |
| 申请人 | Nec Corp; | 发明人 | KANO TSUNEO; | ||||
| 摘要 | PURPOSE: To constitute the controller so that abnormality of a flow rate control valve caused by adhesion of particles, etc., can be known quickly by outputting an alarm signal in the case a difference of outputs from two pieces of mass flow rate sensors provided on a passage of a fluid to be controlled goes off from a prescribed range. CONSTITUTION: When particles, etc., in a fluie adhere to the inside of a passage of a mass flow rate sensor 1 for controlling a flow rate or the inside of a bypass tube 6, and the flow separation balance in an inlet part of the sensor 1 is varied, a difference is generated between a flow rate value shown by the sensor 1 and a flow rate value of a fluid supplied actually from a mass flow rate controller. In this case, a difference between an output signal 11 of the sensor 1 and an output signal 14 of a mass flow rate sensor 2 for comparison exceeds a prescribed range from a regular state and varied, therefore, this variation is detected by a comparing circuit 5, and from the comparing circuit 5, an alarm signal 15 is outputted. In such a way, a worker, etc., can know quickly abnormality of the mass flow rate controller. COPYRIGHT: (C)1991,JPO&Japio |
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