US 11,988,543 B2
Abnormality detection method for flow rate control device, and flow rate monitoring method
Atsushi Hidaka, Osaka (JP); Masaaki Nagase, Osaka (JP); Kouji Nishino, Osaka (JP); Nobukazu Ikeda, Osaka (JP); and Kaoru Hirata, Osaka (JP)
Assigned to FUJIKIN INCORPORATED, Osaka (JP)
Appl. No. 17/755,966
Filed by FUJIKIN INCORPORATED, Osaka (JP)
PCT Filed Nov. 26, 2020, PCT No. PCT/JP2020/044049
§ 371(c)(1), (2) Date May 12, 2022,
PCT Pub. No. WO2021/111979, PCT Pub. Date Jun. 10, 2021.
Claims priority of application No. 2019-220976 (JP), filed on Dec. 6, 2019.
Prior Publication US 2022/0390269 A1, Dec. 8, 2022
Int. Cl. G01F 25/10 (2022.01); G01F 1/36 (2006.01); G05D 7/06 (2006.01)
CPC G01F 25/15 (2022.01) [G01F 1/36 (2013.01); G05D 7/0635 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An abnormality detection method for a flow rate control device provided in a gas supply system, the method comprising:
a step of providing the gas supply system including:
the flow rate control device including a restriction part, a control valve provided upstream of the restriction part, a flow control pressure sensor configured for measuring an upstream pressure between the restriction part and the control valve, and a control circuit configured to control the control valve based on an output of the flow control pressure sensor;
an inflow pressure sensor configured for measuring a supply pressure upstream of the control valve; and
an upstream on/off valve provided upstream of the inflow pressure sensor;
a step of closing the upstream on/off valve in a state where a gas flows downstream of the restriction part at a controlled flow rate by controlling an opening degree of the control valve based on the output of the flow control pressure sensor;
a step of measuring a drop in the supply pressure upstream of the control valve using the inflow pressure sensor, after closing the upstream on/off valve while keeping the control valve open; and
a step of diagnosing a condition of the flow rate control device based on a measured drop in the supply pressure.