Pumps are initially distinguished into types based on their method of operation. The two primary pumping mechanisms are kinetic (dynamic) and positive displacement.
Kinetic or dynamic pumps include all pumps that use fluid velocity and the resulting momentum to generate pumping power and move fluid through the system.
Most dynamic pumps are designated as centrifugal pumps, those which use an impeller to accelerate fluids. Centrifugal pumps are the most common type of pump used in industry. There are three basic sub-types of centrifugal pumps:
- Axial Flow Pumps are high flow, low pressure pumps which lift fluid in a direction parallel to the impeller shaft.
- Mixed Flow Pumps are medium flow, medium pressure pumps which push fluid out away from the pump shaft at an angle greater than 90°.
- Radial Flow Pumps are high pressure, low flow pumps which accelerate fluid along the impeller blades perpendicular to the shaft.
There are also a number of special types of dynamic pumps which are defined by certain characteristics.
- Cantilever Pumps are centrifugal pumps with long cantilever design used in sump pump applications.
- Jet Pumps are kinetic pumps with an ejector attached at the discharge outlet, utilizing the Venturi effect and motive fluid to generate pumping pressure.
- Turbine Pumps are centrifugal pumps that use pressure in combination with a rotary mechanism with numerous small impellers and vanes to transfer energy to a fluid.
Positive Displacement Pumps
Positive displacement pumps include all pumps which use fixed volume cavities displaced using a mechanical force to move fluid through the system. These pumps differ based on whether the motion used to displace the chamber is reciprocating or rotary.
Reciprocating pumps use linear rather than rotary motion to move fluids. They utilize a piston or diaphragm which draws fluid in (upstroke) and pushes it out (downstroke), using check valves to regulate and direct flow through the system.
- Bladder Pumps consist of a flexible, squeezable bladder encased in a rigid outer casing. They are low-flow pneumatic devices for sampling applications.
- Diaphragm Pumps use a diaphragm that moves back and forth to transport liquids from one place to another.
- Double Diaphragm Pumps use two reciprocating diaphragms to compress and pump fluid.
- Peristaltic Pumps use rotating rollers pressed against flexible tubing to create a pressurized flow.
- Piston Pumps and Plunger Pumps use plungers or pistons to push media through a cylinder chamber.
- Triplex Pumps are plunger pumps configured with three plungers for higher pumping power and efficiency.
Rotary pumps move fluid using rotating mechanical motion. As the rotor of the pump spins in a circular motion, liquid is drawn into and forced out of spaces created by the moving parts.
- Gear Pumps use rotating, intermeshing gears to compress fluids and generate flow.
- Progressing Cavity Pumps use rotating mechanisms to push fluids through continuously moving open cavities.
- Rotary Lobe Pumps use rotating lobes to direct flow.
- Rotary Vane Vacuum Pumps use two or more rotating vanes to move media from inlet to outlet generating a region of low pressure.
- Screw Pumps use one or more screws to transfer fluids or materials along an axis.