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:
Jun. 02, 1998
Filed:
May. 29, 1997
Akira Ohtsuka, Tokyo, JP;
Chosei Kaseda, Tokyo, JP;
Yamatake-Honeywell Co., Ltd., , JP;
Abstract
In a control valve abnormality detection method of detecting abnormality in a control valve, a characteristic expression representing the relationship between three factors in the normal state of the control valve is pre-set. The three factors consist of the displacement of the valve stem, a driving force from the valve stem driving device which changes upon displacement of the valve stem, and the force of the fluid which acts on one end of the valve stem through the valve. The three factors are detected on the basis of measurement result. On the basis of two factors selected from the detected three factors, the estimated value of one factor, which is not selected, is calculated by using the pre-set characteristic expression. The detected value of one factor, which is not selected, is compared with the calculated estimated value, and abnormality in the control valve is determined on the basis of the comparison result. A control valve abnormality detection apparatus is also disclosed.