A foot valve is a one-way valve installed at the bottom of a water pump's suction pipe. Its core working principle is that the valve disc opens under fluid pressure and automatically closes when the pump stops, relying on pressure difference, gravity, or spring force. This prevents backflow, maintains stable pressure and liquid level in the pipeline system, ensures efficient pump startup, and prevents water hammer and pump damage.

Working Principle and Structure: The foot valve is based on a one-way valve design, and its operation consists of two stages:

* Opening Stage: When the pump starts, a negative pressure is created in the suction pipe. The fluid pressure pushes the valve disc upwards, allowing fluid to enter the pipeline system.

* Closing Stage: After the pump stops, the fluid pressure disappears or backflow occurs. The valve disc quickly returns to its original position and closes under the action of pressure difference, gravity, or spring force, sealing the valve inlet and preventing backflow.

Key structural components include:

* Valve Body and Cover: Form the main frame. Materials can be gray cast iron, stainless steel, or plastic.

* Valve Disc: The core component, driven to open or close by fluid pressure.

* Sealing Components: Ensure airtightness when closed. Auxiliary design features: Some models include a spring to enhance closing force, or a filter to prevent clogging.