Fabricated gate valves

A gate valve has a hollow substantially T-shaped housing having opposed tubular ends through which a pair of coaxial sleeves extend, the sleeves terminating in the interior of the housing in a pair of seats. A gate includes a pair of gate members which are movable in the space between the seats to and from closed positions engaging the seats. The gate members are moved by a structure which first displaces the gates transversely to the common axis of the sleeves until the gates are in a position of alignment with the sleeves, and then while the structure which moves the gates continues to operate, a stop engages the gate members to guide them for movement into engagement with the seats. When engaging the stop the gate members move along the common axis of the sleeves. The sleeves serve to protect the housing from the effects of temperature fluctuations of the fluid flowing through the sleeves. In addition the sleeves can readily be removed and replaced as required. Preferably at least the sleeves and in addition the other components of the valve are made of forged or rolled steel so that the valve does not have any cast steel components which are likely to crack as a result of casting deficiencies or flaws.  A gate valve comprising housing means having a hollow interior and opposed coaxial tubular ends each with an integral end flange, cylindrical tubular means removably carried by said housing means extending between said ends and fixedly secured to said end flanges and with said housing means during operation of said valve and having a central axis along which fluid is adapted to flow, said tubular means terminating internally of said housing means opposite from said end flanges in spaced seat means integral at the inner end of each said tubular means and removable with said tubular means through a selected one of said tubular ends, said seat means disposed normal to said axis to form a parallel gap therebetween, gate means situated internally of said housing means and having a closed position engaging said seat means only in a plane normal to said axis for providing a fluid-tight seal and preventing flow of fluid through said tubular means and an open position situated beyond the axis of said tubular means for enabling flow of fluid therethrough, said tubular means being in removable threaded engagement with said housing means for a short axial distance at said end flange for a distance substantially less than the axial length of the tubular means and of the adjacent housing, the non-treaded portion of said tubular means having an outside diameter substantially less than the inside diameter of said housing means to provide an annular clearance therebetween to thereby thermally shield said housing from temperature influences produced by the fluid which flows through said tubular means, moving means operatively connected for moving said gate means between said open and closed positions thereof, said moving means when moving said gate means from said open to said closed position first moving said gate means transversely with respect to said axis to a position of alignment with said seat means while still being spaced therefrom, and stop means situated in said housing means in the path of movement of said gate means from said open toward said closed position thereof for stopping the movement of said gate means by said moving means transversely with respect to said axis when said gate means reaches said position of alignment with said seat means, said moving means after displacing said gate means to said position of alignment determined by said stop means then cooperating with said gate means for displacing the latter only in an axial direction into said fluid seal engagement with said seat means to assume said closed position, said stop means guiding said gate means during seating movement thereof into engagement with said seat means by the continued operation of said moving means.

                                                                                                          Shanghai Remy Valve Manufacturing Co., Ltd 

2012-01-19 05:57