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.
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.
The head coefficients, or pressure coefficients, of peripheral pumps, exceed those of side channel pumps, and their characteristic curves are steeper. The pump input power of peripheral pumps decreases with increasing flow rate.
Peripheral pumps with several blade wheels arranged at the various diameter levels of the impeller are considered multistage pumps. For low flow rates, peripheral pumps can partly be used for the same applications as high-pressure geared pumps and even positive displacement pumps.
Another characteristic of peripheral pumps is that, unlike other centrifugal pumps, they can transport fluids with a relatively high gas content. Even severe vapor bubble formation will not lead to flow cut-off or have a major impact on the pump’s smooth running. The H/Q curve will deviate gradually rather than suddenly from the H/Q curve measured in cavitation-free conditions.
- Transport fluids with a relatively high gas content