John W Clove

US Patent:

59506679, Sep 14, 1999

Filed:

Apr 2, 1998

Appl. No.:

9/054283

Inventors:

Mark R. Nicewonger - Aptos CA
John W. Clove - Santa Clara CA

Assignee:

Proteus Industries, Inc. - Mountainview CA

International Classification:

F16K 1720

US Classification:

137459

Abstract:

An apparatus detects an opening in a fluid flow passageway such as occurs when a resistance welding cap which is cooled by the fluid flow becomes accidently detached from a welding machine. Upon detection of an opening, an air-actuated pinch lever is activated to quickly pinch shut flexible fluid inlet and outlet hoses and thereby shut off the fluid flow. Inlet and outlet flow rate sensors provide periodic outputs to a digital computer which determines directions of inlet and outlet flow acceleration. If either the inlet or outlet acceleration changes direction, a baseline inlet or outlet flow rate is set equal to the corresponding current flow rate value to prevent erroneous opening detection due to normal flow fluctuations. If the inlet and outlet accelerations are in the same direction, the baseline values are similarly updated. If the inlet acceleration is positive and the outlet acceleration is negative, it indicates a probable opening.