Gate valve disc

Claim 2

In a gate valve having a body provided with a flow passageway and having a disc receiving guide slot transversely intersecting the passageway, a valve stem having one end portion axially movable within the disc slot toward and away from the axis of the passageway and having a pair of disc seat rings formed from material having a Rockwell scale C hardness of at least forty disposed, respectively, on the upstream and downstream sides of the disc slot coaxial with respect to the passageway and defining confronting seat ring surfaces respectively disposed in the planes forming the upstream and downstream sides of the slot, the improvement comprising: a metallic disc slidable within the disc slot, said disc having a head portion removably secured to said one end portion of said valve stem for moving said disc and opening and closing the passageway, said disc having a transverse U-shaped opening, at least equal in area to the transverse cross-sectional area of the passageway, in its end portion opposite said disc head portion and having a transverse aperture communicating with the Ushaped opening and coaxial with the passageway when said disc is in valve closed position and being at least diametrically equal to the diameter of the passageway; and, a plug formed of material having a Rockwell scale C hardness of at least forty freely received by the disc aperture and slidably interposed between said disc seat rings for coaxially registering and sealing with said disc seat ring on the downstream side of the disc slot and closing the passageway when said disc is moved to a valve closed position.

Claim 3

The gate valve according to claim 1 in which the tolerance between the diameter of said plug and the disc aperture permits the axis of said plug to be tilted on an acute angle, by fluid pressure thereagainst, with respect to the axis of the passageway when sealingly contacting said downstream seat ring.

Claim 4

In a gate valve having a body provided with a flow passageway and having a disc receiving guide slot transversely intersecting the passageway, a valve stem having one end portion axially movable within the disc slot toward and away from the axis of the passageway and having a pair of disc seat rings formed from material having a Rockwell scale C hardness of at least forty disposed, respectively, on the upstream and downstream sides of the disc slot coaxial with respect to the passageway and defining confronting seat ring surfaces respectively disposed in the planes forming the upstream and downstream sides of the slot, the improvement comprising: a metallic disc slidable within the slot, said disc having a head portion removably secured to said one end portion of said valve stem for moving said disc and opening and closing the passageway, said disc having a transverse opening, having its axis parallel with the axis of the passageway and at least equal in area to the transverse cross-sectional area of the passageway, in its end portion opposite said disc head portion and having a transverse aperture coaxial with the passageway when said disc is in valve closed position and being at least diametrically equal to the diameter of the passageway, said disc having a recess in its upstream and downstream surface providing communication between the aperture and the opening; and, a plug formed of material having a Rockwell scale C hardness of at least forty freely received by the disc aperture and slidably interposed between said disc seat rings for coaxially registering and sealing with said disc seat ring on the downstream side of the disc slot and closing the passageway when said disc is moved to a valve closed position.

Claim 5

In a gate valve having a body provided with a flow passageway and having a disc receiving guide slot transversely intersecting the passageway, a valve stem having one end portion axially movable within the disc slot toward and away from the axis of the passageway and having a pair of disc seat rings formed from material having a Rockwell scale C hardness of at least forty disposed, respectively, on the upstream and downstream sides of the disc slot coaxial with respect to the passageway and defining confronting seat ring surfaces respectively disposed in the planes forming the upstream and downstream sides of the slot, the improvement comprising: a metallic disc slidable within the slot, said disc having a head portion removably secured to said one end portion of said valve stem for moving said disc and opening and closing the passageway, said disc having a transverse opening, having its axis parallel with the axis of the passageway and at least equal in area to the transverse cross-sectional area of the passageway, in its end portion opposite said disc head portion and having a transverse aperture coaxial with the passageway when said disc is in valve closed position and being at least diametrically equal to the diameter of the passageway, said disc having a recess in its upstream and downstream surface providing communication between the aperture and the opening; and, a plug formed of material having a Rockwell scale C hardness of at least forty freely received by the disc aperture and slidably interposed between said disc seat rings for coaxially registering and sealing with said disc seat ring on the downstream side of the disc slot and closing the passageway when said disc is moved to a valve closed position.