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. 29, 1993
Filed:
Aug. 24, 1992
Joel T Fisher, South St. Paul, MN (US);
Richard D Lewis, Bloomington, MN (US);
Charles Rescorla, Plymouth, MN (US);
Graco Inc., Golden Valley, MN (US);
Abstract
An air valve having a runaway control feature, including a movable piston which is insertable into air blocking position in a valve passage, a diaphragm separating two chambers, one chamber being coupled to the air passage upstream of the movable piston and the other chamber coupled to the air passage downstream of the movable piston, a rod movable by the diaphragm to activate a second air valve, the second air valve controlling the flow of air from the air passage upstream of the piston valve to the piston valve itself, thereby forcing the piston valve to move into air closure position in the passageway when the pressure drop upstream and downstream of the piston valve exceed predetermined limits. The invention includes a test feature which includes a third valve for manually unbalancing the air pressure across the diaphragm chambers to simulate the runaway air flow condition and thereby actuate the piston valve closure.