Peripheral pumps, also referred to as regenerative pumps, are centrifugal pumps whose impeller rotates in a largely concentric casing channel with an inlet and an outlet opening. As the fluid handled repeatedly circulates between the impeller and the casing channel the energy transferred to it is very high.
In total the fluid moves along the circumference from the inlet to the outlet of the casing with increasing pressure. A stripper arranged between the outlet and the inlet prevents a hydraulic short circuit between the high-pressure and the low-pressure side of the casing channel.
Due to the large increase in energy, peripheral pumps can be relatively small in size. They are often designed as close-coupled pumps.