What occurs if the discharge valve is closed on a rotary pump?

When the discharge valve on a rotary pump is closed, the pressure in the system will increase because the rotary pump continues to operate and create displacement. If the pressure reaches a certain threshold, this can lead to potential damage to the pump or the connected systems. In many pump designs, including rotary pumps, a relief valve is incorporated as a safety feature to prevent damage from overpressure situations.

When the discharge valve is closed, the relief valve opens to relieve the pressure, allowing fluid to bypass back to the suction side or to a designated discharge location. This function protects the pump from experiencing excessive pressure that could cause seals or other components to fail, thus prolonging the life of the pump and maintaining safe operating conditions.

In contrast, if the pumping system was designed without a relief valve, the consequences could be severe, leading to mechanical failure or damage due to overpressure conditions. Understanding the function of the relief valve and its activation when the discharge side is obstructed is crucial for maintaining operational integrity in rotary pump systems.