The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 2000
Filed:
Jan. 15, 1999
Toru Horiuchi, Higashimurayama, JP;
SMC Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a self-diagnosis method for a mass flow controller comprising a pressure control valve, a first shut off valve for performing opening/closing operation on an inflow side of the pressure control valve, an orifice disposed on an outflow side of the pressure control valve, a pressure sensor for detecting an inflow side pressure of the orifice, and a second shut off valve for performing opening/closing operation on an outflow side of the orifice. The first shut off valve is in an open state and the second shut off valve is in a closed state while the pressure control valve is in a fully open state so that a previously determined gas having a predetermined pressure is charged via the first shut off valve into a pipework ranging from the first shut off valve to the second shut off valve. Subsequently, the first shut off valve is in a closed state and the second shut off valve is in an open state so that the gas charged in the pipework is allowed to cause outflow. Diagnosis is performed for the mass flow controller on the basis of a period of time required to lower a detection pressure detected by the pressure sensor to a previously determined detection pressure as a result of the outflow. This self-diagnosis process requires no hardware to be newly added, other than hardware necessary for ordinary operation of the mass flow controller.