Method of detecting abnormalities in flow rate in pressure-type flow controller

Patent 6450190 Issued on September 17, 2002. Estimated Expiration Date:

April 6, 2021. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Method of compensating for changes in the flow characteristics of a dispensed fluid to maintain the volume of dispensed fluid at a setpoint
Patent #: 5054650
Issued on: 10/08/1991
Inventor: Price

Mass flow controller with supplemental condition sensors
Patent #: 5129418
Issued on: 07/14/1992
Inventor: Shimomura, et al.

Method and apparatus for detection of orifice clogging in pressure-type flow rate controllers Patent #: 6302130
Issued on: 10/16/2001
Inventor: Ohmi, et al.

Inventors

Assignee

Application

No. 826834 filed on 04/06/2001

US Classes:

137/14, Involving pressure control137/486, Responsive to change in rate of fluid flow137/487.5, Electrically actuated valve137/557, Fluid pressure responsive indicator, recorder or alarm340/611Pressure

Examiners

Primary: Buiz, Michael
Assistant: Krishnamurthy, Ramesh

Attorney, Agent or Firm

Griffin & Szipl, P.C.

Foreign Patent References

8-338546 JP. 12/13/1996
WO-00/11531 WO. 03/13/2012

International Class

G05D 007/06

Foreign Application Priority Data

1999-08-10 JP

Abstract

A method of detecting abnormalities in flow rate in pressure-type flow controller. The method checks the flow rate for abnormalities while controlling the flow rate of fluid in a pressure-type flow controller FCS using an orifice--the pressure-type flow controller wherein with the upstream pressure P1 maintained about two or more times higher than the downstream pressure P2, the downstream flow rate QC is calculated by the equation QC =KP1 (K: constant) and wherein the control valve CV is controlled on the basis of the difference signal QY between the calculated flow rate QC and the set flow rate QS.