A positive displacement pump requires what on its discharge side?

A positive displacement pump requires what on its discharge side?

• A. Relief valve on its discharge side
• B. Inline filter on the discharge line
• C. Backflow check valve on the suction line
• D. Pressure gauge on the discharge line

Answer: (A)

The key idea is overpressure protection for a positive displacement pump. These pumps move a fixed amount of fluid per cycle, so if the discharge path is blocked or highly restricted, pressure can rise rapidly and reach damaging levels. A relief valve on the discharge side stays closed during normal operation but automatically opens if the pressure exceeds a preset limit, diverting excess fluid back to the reservoir or suction line. This keeps the pump, seals, and piping safe and allows a controlled restart after a blockage clears. An inline filter is useful for protecting downstream equipment and removing contaminants, but it does not prevent overpressure. A backflow check on the suction line prevents reverse flow, not pressure buildup on discharge. A discharge pressure gauge provides indication, not protection, and doesn’t limit the pressure.

The key idea is overpressure protection for a positive displacement pump. These pumps move a fixed amount of fluid per cycle, so if the discharge path is blocked or highly restricted, pressure can rise rapidly and reach damaging levels. A relief valve on the discharge side stays closed during normal operation but automatically opens if the pressure exceeds a preset limit, diverting excess fluid back to the reservoir or suction line. This keeps the pump, seals, and piping safe and allows a controlled restart after a blockage clears.

An inline filter is useful for protecting downstream equipment and removing contaminants, but it does not prevent overpressure. A backflow check on the suction line prevents reverse flow, not pressure buildup on discharge. A discharge pressure gauge provides indication, not protection, and doesn’t limit the pressure.