Types of Pumps Glossary

Four Basic Pump Types

Just about every pump on the market can be categorized as one of four very basic types of pump: positive displacement pumps, velocity pumps, impulse pumps, and gravity pumps. Each type of pump uses a different method to move water. Understanding these four basic methods will give you a better grasp of how many of the pumps on the market operate.

Gravity Pump

- literally uses gravity to move water. It only works if the water source is at a higher elevation than the point you are trying to pump water to. For example, if you had an aquifer on a mountain (point A), and were trying to pump water from it to a valley below (point B), you would run a pipe line from point A down to point B, and apply a small amount of suction to the pipeline at point B. This would get the water flowing, and it would continue to flow until the aquifer ran dry. You could cap the end of the pipe at point B, or put a valve on it, but as soon as you removed the cap or opened the valve, the water would begin to flow again, without re-applying suction.

Impulse Pump

- uses trapped gas (usually air) to create pressure which pushes the water into the discharge pipe.

Positive Displacement Pump

- moves water by alternately trapping a fixed amount and then forcing that trapped water into the discharge pipe.

Velocity Pump

- moves water by increasing the flow velocity, and then converting the energy increase (which occurs when the velocity is reduced as the flow enters the discharge pipe) into pressure, which forces the water up the discharge line.

Axial Flow Pump

- a type of velocity pump designed specifically for high flow and low head.

Booster Pump

- used to increase water pressure in areas where it is insufficient. There are many types of booster pumps for a variety of applications, including corrosion-resistant, hygienic, and non-clog designs for pumping anything from saltwater to fuel to hazardous waste.

Centrifugal Pump

- a type of velocity pump which uses centrifugal force to create the velocity needed for the energy to pressure conversion.

Chopper Pump

- a pump with a special serrated impeller designed to cut large solids passing through the pump to prevent clogging.

Diaphragm Pump

- a type of positive displacement pump which uses pressurized air to push the diaphragm, which in turn pushes the water out of the chamber and into the discharge pipe.

Double Suction Pump

- has a closed impeller with two water intake points, instead of one. This provides very stable, reliable performance because the hydraulic forces are balanced.

Double Volute Pump

- double volute literally means double housing; this type of pump has a partition, or second wall, inside the pump housing, which divides the flow of water from the impeller to the discharge pipe into two streams, which reduces the radial load on the impeller, allowing the pump to run more smoothly.

End Suction Pump

- the most common type of centrifugal pump. Composed of a horizontal shaft and a single impeller, the end suction pump pulls water in one end of the casing and discharges out the top.

External Gear Pump

- a type of positive displacement pump composed of two side-by-side interlacing gears in a single housing. The rotation of the gears pumps the liquid around the perimeter of the inside of the housing and out the discharge pipe. External gear pumps are used for high pressure industrial applications.

Gravity Pump

- literally uses gravity to move water. It only works if the water source is at a higher elevation than the point you are trying to pump water to. For example, if you had an aquifer on a mountain (point A), and were trying to pump water from it to a valley below (point B), you would run a pipe line from point A down to point B, and apply a small amount of suction to the pipeline at point B. This would get the water flowing, and it would continue to flow until the aquifer ran dry. You could cap the end of the pipe at point B, or put a valve on it, but as soon as you removed the cap or opened the valve, the water would begin to flow again, without re-applying suction.

Impulse Pump

- uses trapped gas (usually air) to create pressure which pushes the water into the discharge pipe.

Internal Gear Pump

- a type of positive displacement pump composed of two gears- a smaller gear inside an interlacing larger gear. The water is trapped in the gaps between the gear cogs as it rotates, and is pushed out the discharge pipe.

Jet Pump

- consists of two pipelines connected to an above-ground centrifugal pump. One pipeline (usually the smaller of the two) forces water away from the centrifugal pump, back down into the well. This creates enough pressure in the well to push water into the second pipeline, which uses the venturi effect to pull the water up to the centrifugal pump. Jet pumps are less expensive than submersible pumps, and work well in low pressure applications.

Lobe Pump

- a type of positive displacement pump used primarily in food applications. The design is a variation of the external gear pump.

Low NPSH Pump

- a type of centrifugal pump designed for low head applications; has an inducer to serve as a booster pump to the main impeller.

Multistage Pump

- a type of centrifugal pump designed for low head applications; has an inducer to serve as a booster pump to the main impeller.

Peripheral Pump

- also known as a regenerative turbine pump. A type of velocity pump very similar to a centrifugal pump, designed for low capacity/high head applications.

Pitot Pump

- also called a rotating casing pump. The pitot pump is designed for medium/low flow rates at high pressures.

Progressive Cavity Pump

- a type of positive displacement pump which uses a stator and rotor assembly to move the water. The rotor fits snugly in the stator, and as it rotates, it forms separate sealed cavities along the entire length of the stator assembly. These sealed cavities hold the liquid being pumped, and move progressively down the length of the assembly as the rotor rotates, and the liquid is ejected as each cavity reaches the end of the assembly.

Radial Flow Pump

- a specific design of centrifugal pump; used for medium head/medium flow or high head/low flow applications.

Radial Vane Pump

- also called a partial emission pump or vane pump. Radial vane pumps are specifically designed to handle corrosive chemicals at low flows.

Recessed Impeller Pump

- sometimes called a vortex pump; the impeller is recessed against one wall of the casing, rather than being centered in the casing. This design allows it to pump some solids, air entrained liquids, or shear-sensitive liquids.

Regenerative Pump

- see peripheral pump

Sealless/Glandless Pump

- this is a highly leak resistant type of pump designed specifically for handling highly volatile, radioactive, or toxic liquids.

Self-Priming Pump

- any pump that does not require priming or filling with liquid before every start-up. Self-priming pumps have a reservoir of water in the casing that helps create the suction at start-up.

Side Channel Pump

- this pump’s design forces the liquid or liquid/gas combination being pumped to move between the impeller blades many times before being forced into the discharge pipe. This creates a buildup of centrifugal force, and therefore a pump head that is 5-10 times stronger than that of a standard centrifugal pump. The side channel pump is capable of creating high head at low flow, as well as pumping gases.

Sludge Pump

- a pump with a built-in agitator that prevents sludges from settling. Some types of sludge are prone to rapid settling, and therefore are hard to keep in motion.

Slurry Pump

- a heavy-duty pump used primarily in the mining industry. Slurry pumps are designed specifically to handle abrasive slurries with particles of different sizes.

Steam Pump

- any pump powered by a steam engine.

Valveless Pump

- any pump which does not require a valve to operate; a gravity pump is an example of a valveless pump.

Vane Pump

- see radial vane pump

Vertical Turbine Pump

- a type of centrifugal pump designed to be vertically inserted into a bore-hole well, open reservoir, or river.

Viscous Drag Pump

- a pump with a vaneless impeller; relies on contact between the water and a flat, rotating impeller to move the water.

Vortex Pump

- see recessed impeller pump