Regenerative pumps employs a combination of mechanical impulse and centrifugal force to produce heads of several hundred feet at low volumes, usually less than 100 gal/min. the impeller, which rotates at high speed with small clearances, has many short radial passages milled on each side at the periphery. These pumps are particularly useful when low volumes of low-viscosity liquids must be handled at higher pressures than are normally available with centrifugal pumps.