The valve stem is driven to move linearly by rotating the handwheel to cut off or conduct the fluid.
The working principle of concealed stem gate valve can be summarized as the following core mechanisms:
Transmission structure
When the handwheel is rotated, the valve stem converts the rotary motion into linear motion through thread or gear transmission. The nut at the top of the valve stem cooperates with the guide groove of the valve body to ensure that the valve stem only moves up and down linearly without rotating. This design avoids the exposure of the valve stem and is suitable for installation environments with limited space.
Gate action and sealing
Closing process: Turn the handwheel clockwise, the valve stem pushes the gate down and fits tightly with the valve seat. The sealing force is formed by the combined action of the gate gravity, the valve stem thrust and the fluid pressure.
Opening process: Turn the handwheel counterclockwise, the gate moves up and leaves the valve seat, the fluid channel is fully opened, and the flow resistance is minimized.
The gate structure is divided into parallel or wedge-shaped, the latter of which enhances the sealing wedge gate sealing principle through angle design.
Key Components Collaboration
Valve stem: Usually made of stainless steel, the bottom trapezoidal thread cooperates with the gate guide groove to ensure movement accuracy.
Packing and gasket: Seal the gap between the valve stem and the valve body to prevent medium leakage.
Operational Characteristics
The opening and closing torque must be controlled within 240N·m, which is convenient for single-person operation.
The standard requires that the opening and closing direction is unified as clockwise closing, and the number of revolutions does not exceed 600 revolutions (large-diameter valves).
