Internal structure of the cast iron water pump gate valve

The internal structure of a cast iron gate valve mainly consists of the following key components, which work together to enable the valve to open, close, and maintain a seal:  

**Valve body**: Serving as the main structure of the valve, the valve body is the essential component for installing the valve cover, accommodating the valve seat, and connecting to the pipelines. It is typically made of cast iron materials such as gray cast iron or ductile iron, which provide good strength and corrosion resistance.  

**Valve cover**: Combined with the valve body, it forms a pressure-resistant cavity and contains the packing gland, which holds the packing to ensure a seal. The valve cover is also connected to the support bracket and the gland, providing structural support.  

**Valve stem**: It connects the operating mechanism (such as a handwheel or an electric actuator) to the gate plate, transmitting the operating torque through rotational or linear motion to control the opening and closing of the gate plate. Valve stems can be divided into exposed stem and concealed stem types.  

**Gate plate**: As the component that opens and closes the valve, the gate plate moves perpendicular to the flow direction to block or allow the passage of fluid. It can be designed in wedge-shaped configurations (such as single-gate, double-gate, or elastic gate plates) or parallel configurations (also with single or double gate plates) to suit various operating conditions.  

**Valve seat**: Fixed on the valve body, it forms a sealing pair with the gate plate. Valve seats are usually made of stainless steel, cemented carbide, or elastic materials (such as rubber or PTFE) to enhance wear resistance and sealing reliability.  

**Packing and packing gland**: The packing is installed inside the packing gland and compressed by the packing gland to seal the gap between the valve stem and the valve cover, preventing the leakage of the medium.  

**Support bracket and valve stem nut**: The support bracket supports the valve stem and the operating mechanism, while the valve stem nut connects to the actuator, converting external power into the linear motion of the gate plate.  

In addition, some modern cast iron gate valve designs also incorporate optimized features such as **integrated rubber-coated gate plates** (which enhance sealing performance and durability) and **flat-bottomed valve seats** (which reduce the accumulation of debris and improve fluid flow efficiency). These components collectively ensure the high efficiency and reliability of the gate valve in fluid control applications.