Title:
VACUUM PUMP, MAIN SENSOR, AND SCREW GROOVE STATOR
Document Type and Number:
WIPO Patent Application WO/2018/173704
Kind Code:
A1
Abstract:
[Problem] To provide a vacuum pump provided with a sensor capable of detecting that a deposit has accumulated in a flow passage to a prescribed thickness, even if the chemical composition of the deposit in the flow passage cannot be identified.
[Solution] A vacuum pump 1 includes: a rotating portion and a fixed portion between which an internal flow passage is formed; an exhaust mechanism which feeds gas from a suction inlet port through the internal flow passage toward an exhaust port; and a main sensor 42 for detecting that a deposit has reached a prescribed thickness in a detection position in the internal flow passage. The main sensor 42 includes at least a pair of electrodes 54, 56 disposed in the internal flow passage with a spacing corresponding to the prescribed thickness, and an electrostatic capacitance detecting circuit 46 which is connected to the pair of electrodes 54, 56 to detect an electrostatic capacitance between the pair of electrodes 54, 56. The electrostatic capacitance detecting circuit 46 determines that the deposit in the internal flow passage has reached the prescribed thickness on the basis of a reduction in a rate of increase of the electrostatic capacitance.
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Inventors:
KABASAWA TAKASHI (JP)
Application Number:
PCT/JP2018/008139
Publication Date:
September 27, 2018
Filing Date:
March 02, 2018
Export Citation:
Assignee:
EDWARDS JAPAN LTD (JP)
International Classes:
G01B7/06; F04D19/04
Domestic Patent References:
| WO2012077411A1 | 2012-06-14 |
Foreign References:
| JPH06101655A | 1994-04-12 | |||
| JPS60217982A | 1985-10-31 | |||
| JPH1123511A | 1999-01-29 | |||
| JPH06101655A | 1994-04-12 | |||
| JPH06109409A | 1994-04-19 |
Other References:
See also references of EP 3605008A4
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