The structure of the gate valve body determines the connection between the valve body and the pipeline, the valve body and the bonnet. In terms of manufacturing methods, there are casting, forging, forging welding, casting welding and tube sheet welding. Forged valve bodies have developed towards larger diameters, while cast valve bodies have gradually developed towards smaller diameters. Any kind 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 bore type and reduced bore type. The diameter of the flow passage is basically the same as the nominal diameter of the valve, which is the full diameter type; the diameter of the flow diameter is smaller than the nominal diameter of the valve, which is called the reduced diameter type. There are two types of reduced diameter shapes: uniform diameter reduction and fee uniform diameter reduction. The taper-shaped flow channel is a kind of non-uniform diameter reduction. The aperture of the inlet end of this type of valve is basically the same as the nominal diameter, and then gradually shrinks to the minimum at the valve seat.

The use of reduced-diameter flow channel (whether it is a tapered tube-shaped non-uniform diameter reduction or uniform diameter reduction), its advantage is that the valve of the same specification can reduce the size of the gate, the opening and closing force and the moment; the disadvantage is that the flow resistance increases and the pressure The reduction and energy consumption increase, so the shrinkage cavity should not be too large. For tapered tube diameter reduction, the ratio of the inner diameter of the valve seat to the nominal diameter is usually 0.8 to 0.95. For reduced-diameter valves with a nominal diameter of less than 250mm, the inner diameter of the seat is generally one step lower than the nominal diameter; for reduced-diameter valves with a nominal diameter equal to or greater than 300mm, the inner diameter of the valve seat is generally lower than the nominal diameter by two steps.