Peripheral pumps

The peripheral pump, also known as the regenerative pump, is a centrifugal pump , whose impeller rotates in an approximately concentric casing channel with inlet and outlet openings. As the fluid handled is repeatedly circulated between the impeller and the casing channel, the energy transferred to it is very high.

In short, the fluid moves along the circumference from the inlet to the outlet of the casing as the pressure increases. The vapor lift tower placed between the outlet and the inlet prevents a hydraulic short circuit between the high and low pressure sides of the casing channel.

The size of the peripheral pumps can be relatively small due to the large increase in energy. They are usually designed as tightly coupled pumps.
Peripheral pumps have head coefficients or pressure coefficients that exceed those of side channel pumps, and they have steeper characteristic curves. The pump input power of peripheral pumps decreases as the flow rate increases.

Peripheral pumps with multiple impellers arranged at different diameter levels of the impeller are considered multistage pumps. At a common speed of 2,900 rpm, they can produce a pressure head of up to 1,200 m. For low flow rates, peripheral pumps can be used in part with high pressure gear pumps.

Another feature of peripheral pumps is that, unlike other centrifugal pumps, they can convey fluids with relatively high gas content. Even severe bubble formation will not cause flow cut-off or have a significant impact on the smooth operation of the pump. the H/Q curve will gradually deviate from the H/Q curve measured under cavitation-free conditions, rather than deviating abruptly. Another advantage is the symmetrical flow direction.

Peripheral pumps are less efficient than runoff pumps. They are suitable for pumping uncontaminated liquids, for example as boiler feed pumps for small boilers, booster pumps, car wash pumps, pumps for the chemical industry and all applications where low flow rates must be pumped at high pressures.