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. 16, 1993
Filed:
Nov. 22, 1991
Applicant:
Inventor:
M Dale Mayes, Baton Rouge, LA (US);
Assignee:
The Dow Chemical Company, Midland, MI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16K / ;
U.S. Cl.
CPC ...
137244 ; 251122 ;
Abstract
An improved control valve assembly that resists plugging by fluids contaminated with sticky solids, e.g. sludge or particulates, comprising a valve containing a modified valve trim having a stepped cross-section rather than a continuous taper created by reducing the diameter of the valve stem at a point on the stem corresponding to a position of 90 percent open, so that the modification causes the flow area to suddenly increase drastically when the valve opens to 90 percent open in response to flow falling below a predetermined setpoint.