Diffuser Pump

The diffuser pump is a kind of radial flow centrifugal pump that differentiates itself from other centrifugal pumps by the fact that it encompasses a ring of fixed vanes. After leaving the impeller, the fluid is passed through these vanes and diffused. In this way, a more controlled flow is obtained and the efficiency of the conversion of velocity head into pressure head is increased.

By adding stationary diffuser vanes to a large impeller pump, efficiency rates of 90 percent can be achieved. The number of impeller vanes is never the same with the number of diffuser vanes. In this way thumping and knocking are avoided. Also excessive buildup of pressure is prevented.

As it was said, the diffuser pump is a type of centrifugal pump. A centrifugal pump is a device designed to move liquids and gases. There are two very important parts that a centrifugal pump includes: the impeller, which is a wheel with vanes, and the circular pump casing around it. Such a pump is generally used when working with flows of over 100 gpm at moderate pressures. Flows must be fairly constant and large and the viscosity of the fluid must be a low one.

A parameter that is used to characterize all centrifugal pumps, including the diffuser pump, is the specific speed, which depends on the speed of the impeller, the flow rate and the net positive suction head. It has no measure unit. A diffuser pump works with specific speeds between 500 and 15000.

Here is the way a diffuser pump works: it draws fluid into the impeller at its center and then flings it outward due to the centrifugal force. As it leaves the impeller, the liquid reaches higher pressure and speed than it had at the time it entered. The pump casing, which contains the stationary diffuser blades, then partially transforms the velocity, and especially its tangential component, into additional pressure.

« Back