METHOD FOR DETECTING ABNORMAL FLOW RATE FOR PRESSURE FLOW RATE CONTROLLER

Title:

METHOD FOR DETECTING ABNORMAL FLOW RATE FOR PRESSURE FLOW RATE CONTROLLER

Document Type and Number:

WIPO Patent Application WO/2001/013191

Kind Code:

A1

Abstract:

A method for detecting abnormal flow rate by easily detecting an obstruction of an orifice while a fluid pressure flow rate controller using an orifice is controlling the flow rate. The method uses a flow rate controller (FCS) so as to calculate the flow rate Q¿c? on the downstream side when the upstream-side pressure P¿1? is maintained at a value about twice or more the downstream-side pressure P¿2? from Q¿c?=KP¿1? (K: constant) and to control the operation of a control valve (CV) according to a signal Q¿y? representing the difference between the calculated flow rate Q¿c? and a preset flow rate Q¿s?. A testing circuit or flow rate setting circuit provided separately outputs a testing signal $g(D)Q¿s? having a testing amplitude V¿0? to the control valve (CV). The pressure amplitude V of a pressure variation $g(D)P¿1? of the upstream-side pressure P¿1? occurring in response to the opening/closing of the control valve (CV) is measured. When the pressure amplitude V decreases below a limit amplitude V¿t?, the obstruction of the orifice is announced, thus implementing the method. If the testing signal $g(D)Q¿s? is superimposed on a steady-state preset flow rate signal Q¿s0? and outputted together from the testing circuit or the flow rate setting circuit to the control valve (CV), an abnormal flow rate can be detected while controlling the flow rate by using the steady-state preset flow rate signal Q¿s0?.

Inventors:

OHMI TADAHIRO (JP)
IIDA SEIICHI (JP)
KAGATSUME SATOSHI (JP)
HIROSE JUN (JP)
FUKASAWA KAZUO (JP)
KOIZUMI HIROSHI (JP)
NAGAOKA HIDEKI (JP)
UNO TOMIO (JP)
NISHINO KOUJI (JP)
IKEDA NOBUKAZU (JP)
DOHI RYOUSUKE (JP)
IDETA EIJI (JP)

Application Number:

PCT/JP2000/005043

Publication Date:

February 22, 2001

Filing Date:

July 27, 2000

Export Citation:

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Assignee:

TOKYO ELECTRON LTD (JP)
FUJIKIN KK (JP)
OHMI TADAHIRO (JP)
IIDA SEIICHI (JP)
KAGATSUME SATOSHI (JP)
HIROSE JUN (JP)
FUKASAWA KAZUO (JP)
KOIZUMI HIROSHI (JP)
NAGAOKA HIDEKI (JP)
UNO TOMIO (JP)
NISHINO KOUJI (JP)
IKEDA NOBUKAZU (JP)
DOHI RYOUSUKE (JP)
IDETA EIJI (JP)

International Classes:

G01F1/36; F16K37/00; G05B23/02; G05D7/06; (IPC1-7): G05B23/02; F16K17/22; G05D7/06; G01D21/00

Foreign References:

JPH1163265A	1999-03-05
JPH04160319A	1992-06-03

Other References: