Gate valve

Claim 2

In a gate valve comprising a rigid body structure having an axis and an annular end portion defining an axial passage, a first sealing ring fixed relative to the end portion, a second sealing ring in axially spaced relation to the first sealing ring, a pressure sleeve coaxial with and movable relative to the passage and fixed relative to the second sealing ring, a gate movable between a passage opening position and a passage closing position between the two sealing rings, and shfiting means for selectively applying said second sealing ring against the gate and shifting the second sealing ring away from the gate; the feature that said shifting means comprise in combination a rectangular frame having four corners and four integral side members defining an opening in which the sleeve is located, the side members being adapted and arranged to have substantially optimum stiffness, for a given volume of the material of the side members, in longitudinal planes of the side members parallel to said axis so as to minimize warping of the frame when applying the second sealing ring against the gate, eight connecting means connecting the frame to the sleeve so as to be capable of rigidly transmitting movement of the frame to the sleeve axially of said passage, pairs of the connecting means being disposed on each of the four side members of the frame in spaced relation to the corners of the frame and the eight connecting means being arranged on the periphery of the sleeve symmetrically with respect to said axis, four shifting devices respectively interposed between the body structure and thE corners of the frame and comprising worm-drive mechanisms, and cardan shaft means for driving the worm-drive mechanisms in synchronism and forcefully applying the second sealing ring against the gate.

Claim 3

In a gate valve comprising a body structure having an axis and a first end portion and a second end portion, the end portions being in rigidly fixed axial positions and defining passages aligned on said axis and being adapted to be fixed to pipe sections between which the valve is to be inserted, a first sealing ring fixed relative to the first end portion, a second sealing ring in axially spaced relation to the first sealing ring, a pressure sleeve interposed between the two end portions and coaxial with and axially movable relative to the passages and fixed relative to the second sealing ring, a gate movable between a passage opening position and a passage closing position between the two sealing rings, and shifting means for selectively applying the second sealing ring against the gate and shifting the second sealing ring away from the gate; the feature that the shifting means comprise in combination: a rectangular frame having four corners and four integral side members which define an opening in which the sleeve is located, the side members being adapted and arranged to have substantially optimum stiffness, for a given volume of the material of the side members, in longitudinal planes of the side members parallel to said axis so as to minimize warping of the frame when applying the second sealing ring against the gate, eight connecting means connecting the frame to the sleeve so as to be capable of rigidly transmitting movement of the frame to the sleeve axially of said passages, pairs of the connecting means being disposed on each of the four side members of the frame in spaced relation to the corners and the eight connecting means being arranged on the periphery of the sleeve symmetrically with respect to said axis, four drive means respectively interposed between the body structure and the four corners of the frame for forcefully applying the second sealing ring against the gate and means for driving the four drive means in synchronism.

Claim 4

In a gate valve comprising a body structure having an axis and a first end portion and a second end portion, the end portions being in rigidly fixed axial positions and defining passages aligned on said axis and being adapted to be fixed to pipe sections between which the valve is to be inserted, a first sealing ring fixed relative to the first end portion, a second sealing ring in axially spaced relation to the first sealing ring, a pressure sleeve interposed between the two end portions and coaxial with and axially movable relative to the passages and fixed relative to the second sealing ring, a gate movable between a passage opening position and a passage closing position between the two sealing rings, and shifting means for selectively applying the second sealing ring against the gate and shifting the second sealing ring away from the gate; the feature that the shifting means comprise in combination: a rectangular frame having four corners and four integral side members which define an opening in which the sleeve is located, the side members being adapted and arranged to have substantially optimum stiffness, for a given volume of the material of the side members, in longitudinal planes of the side members parallel to said axis so as to minimize warping of the frame when applying the second sealing ring against the gate, eight connecting means connecting the frame to the sleeve so as to be capable of rigidly transmitting movement of the frame to the sleeve axially of said passages, pairs of the connecting means being disposed on each of the four side members of the frame in spaced relation to the corners and the eight connecting means being arranged on the periphery of the sleeve symmetrically with respect to said axis, four drive means respectively interposed between the body structure and the four corners of the frame for forcefully applying the second sealing ring against the gate and means for driving the four drive means in synchronism.

Claim 5

A valve as claimed in claim 2, further comprising elastically yieldable sealig means interposed between and connected to the body structure and the pressure sleeve.