Where is the foot valve located in a positive displacement chemical feed pump system?

In a positive displacement chemical feed pump system, the foot valve is located at the lower part of the suction tubing. This position is critical because the foot valve functions to maintain the prime in the suction line. By being situated at the bottom of the suction tubing, it prevents backflow of the liquid once the pump is turned off, ensuring that the pump remains filled with the chemical being fed. This allows for consistent operation and effective chemical delivery when the pump is activated.

The design of positive displacement pumps relies on this mechanism to function effectively. If the foot valve were positioned elsewhere, such as at the top of the discharge tubing or at the midpoint, it would not be able to fulfill its primary purpose of keeping the liquid in the suction line, leading to issues with pump priming and efficiency. The discharge valve, meanwhile, is located at the outlet side of the system and is not involved in maintaining suction, which further supports the rationale behind the correct placement of the foot valve in the system.