Importance

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Abstract

A totally open-totally closed valve leakproof shut off device, suitable for backflow prevention, to terminate fluid flow, which comprises a virtual or real keyway between aligned opposite flanges with central openings; said keyway having a lateral opening greater than the lateral dimension of said flange openings. A pair of seated annular seals on opposite sides of the keyway; extend slightly into the keyway to touch each other such that when no key is inserted, fluid flows without leakage; and when a segregable key is inserted into the keyway, it slides between the two seals and closes off the opening of the keyway in a leakproof manner. The device is adaptable for large valves by utilizing retaining means such as hasps and fingers to removably retain the key in place, and by disposing the key internally in a housing from which removal can be achieved by use of an actuator.

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First Claim