Differences in Pump Types
There are a number of different pumps on the market, and it’s important to understand the differences in order to select the right one for your application. The type you will need will depend on the type of liquid you are pumping, the distance you want the liquid to move, and the volume you need over a specific time frame. Since there are so many pumps on the market, there are two types of pumps that work in different ways and will encapsulate most pump designs. These designs are centrifugal pumps and positive displacement pumps. A piston pump, diaphragm pump, gear pump, vane pump, and progressing cavity pump all fall under the category of positive displacement pumps.
Centrifugal Pumps: These are the most common types of pumps used today. This pump will use an impeller, which is a rotating blade to generate suction to move the fluid. The rotating impeller will create the centrifugal force, which gives the pump its name. These pumps can be driven by engine or electric motor. These pumps are used for liquids low in solid concentration and viscosity. There is the centrifugal slurry pump, which can move liquids that have a large amount of particles. There are three types of impeller designs. The axial flow impeller will discharge fluid along the shaft axis. The radial flow impeller will discharge the fluid at 90 degrees to the shaft axis. The mixed flow impeller discharges fluid in a conical direction, using both axial and radial pumping action. These pumps do have the highest flow rate of all pump types and can handle dirty or clean liquids. Liquids shouldn’t contain vapors or air.
Positive Displacement Pumps: These pumps create an expanding cavity on the suction side and a contracting cavity on the discharge outlet. The difference will create pressure, which pulls and pushes fluid simultaneously with enough force to create flow. There are two different designs of these pumps. With reciprocating, these create suction by a piston, which plunges into and pulls out material. Valves are used to make sure the flow will only go in one direction. A reciprocating design will pulse the liquid at identical intervals. A piston pump, plunger pump, and diaphragm pump are considered reciprocating design pumps. A rotary design uses two gears that mesh together. The movement creates the high pressure to create flow. These pumps are better at handling viscous material because of the design. These pumps are used in many different industries where they are favored over centrifugal pumps because of their ability to work with liquids with high viscosity. These are the best choice for moving liquids gently and can be used for certain niches that need low flow or a high-pressure combination.