According to their structural form, cast iron gate valves can be divided into rising stem gate valves and hidden stem gate valves. Further research is needed on the specific structural characteristics and application scenarios.
The opening and closing component of a gate valve is the gate plate, and the direction of movement of the gate plate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate valve has two sealing surfaces, and the most commonly used mode gate valve has two sealing surfaces that form a wedge shape. The wedge angle varies with the valve parameters, usually 50 degrees, and 2 ° 52 'when the medium temperature is not high.
The gate of a wedge gate valve can be made as a whole, called a rigid gate; It can also be made into a gate that can produce slight deformation to improve its processability and compensate for the deviation of the sealing surface angle during the processing. This type of gate is called an elastic gate.
When the gate valve is closed, the sealing surface can be sealed solely by the medium pressure, that is, the sealing surface of the gate is pressed against the valve seat on the other side by the medium pressure to ensure the sealing surface is sealed, which is called self sealing.
The gate of a gate valve that moves in a straight line with the valve stem is called a rising stem gate valve (also known as a lift stem gate valve). Usually, there are trapezoidal threads on the lifting rod, which convert rotational motion into linear motion through the nut at the top of the valve and the guide groove on the valve body, that is, convert operating torque into operating thrust.
Some valves have valve stem nuts installed on the gate plate, and the handwheel rotates to drive the valve stem to rotate, thereby lifting the gate plate. This type of valve is called a rotary stem gate valve or a concealed stem gate valve.
