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:
Feb. 13, 2001
Filed:
Mar. 04, 1999
Applicant:
Inventors:
Bruce F. Grumstrup, Marshalltown, IA (US);
Stephen G. Seberger, Marshalltown, IA (US);
Assignee:
Fisher Controls International Inc., Clayton, MI (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F16K 3/1124 ;
U.S. Cl.
CPC ...
F16K 3/1124 ;
Abstract
An emergency shutdown system for a process control system includes an emergency shutdown (ESD) valve and an associated valve actuator. An emergency shutdown (ESD) controller provides output signals to the ESD valve in the event of a failure in the process control system. A solenoid valve responds to the ESD controller to vent the actuator to a fail state. A digital valve controller (DVC) test strokes the ESD valve. An impedance booster device enables the dc powering of the solenoid valve and the DVC over a two wire line while still permitting digital communication over the same two wire line.