Gate valve body structure and valve body flow path
The structure of the valve body of the gate valve is determined by the connection between the valve body and the pipe, the valve body and the valve cover, and in terms of the manufacturing method, there are several types of casting, forging, forging, casting, and tube sheet welding. The forged valve body has developed toward a large diameter, and the cast valve body has gradually developed toward a small diameter. Any type of gate valve body can be forged or cast, depending on the user's requirements and the manufacturing methods owned by the manufacturer.
The flow passage of the gate valve body can be divided into two types: full-diameter type and reduced-diameter type. The flow passage aperture is nominally the same as the valve through the nominal diameter. The flow aperture is smaller than the nominal diameter of the valve. The reduced diameter shape has two types of uniform diameter reduction and uniform diameter reduction. The flow path is a conical tube shape, which is a non-uniform diameter reduction. The diameter of the inlet end of such a valve is basically the same as the nominal diameter, and then gradually shrinks to a small size at the valve seat.
The use of reduced-diameter flow passages (whether non-uniform diameter reduction or uniform diameter reduction) is advantageous in that the valve of the same specification can reduce the size, opening and closing force and torque of the gate; the disadvantage is that the flow resistance is increased and the pressure is increased. The drop and energy consumption increase, so the shrinkage hole should not be too large. For the tapered tubular diameter, the ratio of the inner diameter of the valve seat to the nominal diameter is usually 0.8 to 0.95. For diameter-reducing Valves with a nominal diameter of less than 250 mm, the inner diameter of the seat is generally lower than the nominal diameter; for a reduced-diameter valve with a nominal diameter of 300 mm or more, the inner diameter of the seat is generally second-order lower than the nominal diameter.
