Foot valve assembly and submerged pump system

A foot valve assembly comprising:

• a cylindrical adapter configured to be attached to a lower opening end of a cylindrical pump column configured to accommodate a pump configured to be submerged in a handling liquid, the cylindrical adapter configured to accommodate a suction port of the pump;
• a valve disc including a flow path defining surface that is located below a lower end surface of the cylindrical adapter and is configured to define, between the lower end surface of the cylindrical adapter and the flow path defining surface, an inflow path that allows the handling liquid to flow into the pump, the valve disc configured to open and close a lower opening of the cylindrical adapter;
• a biasing member that biases the valve disc toward the cylindrical adapter;
• and
• a one-way valve disposed in the inflow path, wherein:
• the one-way valve is configured to open the inflow path, when the valve disc is closed, in response to a pressure of a fluid discharged from the lower opening of the cylindrical adapter, to allow flow of the discharged fluid in a flow direction away from the lower opening of the cylindrical adapter, and
• the one-way valve is further configured to close the inflow path and to seal against flow of the handling liquid toward the lower opening of the cylindrical adapter.