Importance

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Abstract

A friction-free gate valve for regulating gas flow in semiconductor manufacturing comprises a gate which, prior to being lifted up for the valve-opening position, is horizontally flitted away from the passage wall surface against which it was pressed against for valve closure, lest undesirable frittered particles should occur from rubbing the gate against the passage wall surface. The gate is axially coupled to and made integral with a vertically and horizontally movably disposed valve stem. The valve stem is also operatively coupled to a cam mechanism which is actuated by a reciprocating piston rod which, in an earlier part of its stroke, drives vertically the valve stem through the cam mechanism, moving the gate to a lower position where the gate blocks the passage. While the piston rod further moves to cover the remaining part of stroke, additional pressure exerted on the cam mechanism causes the valve stem to tilt, thereby pressing the gate into tight contact with the opposed wall surface of the passage. When the gate is moved out of the passage, the steps are followed backward, by starting the piston rod to reverse the stroke. The gate is first caused to edge away from pressure contact with the surface, then is lifted up.

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First Claim