What Is A Piston Pump And Its Types?

Due to their high efficiency and robustness, piston pumps find use in a wide range of applications. A piston pump is a type of reciprocating pump that is utilized to displace liquids or compressed gasses from one point to another. The piston moves up and down in the compression cylinder, and it is connected with a crankshaft that is supplied power by an electric motor to drive the piston. They are particularly useful in applications where there is a requirement of high consistent pressure.

Piston Pump Parts

Piston pumps consist of many different parts, all of which will be outlined in this section. To begin, piston pumps contain an intake, where an input like a liquid or high-pressure gas is drawn in. Meanwhile, the port plate acts as the separating medium between the input and output port, and the intake is sent via this medium. Next, a rotating barrel serves as the dynamic part of the pump where the pistons are inserted in their specific grooves. As the barrel rotates alongside the pistons, the intake is successfully displaced.

The piston constitutes the most important part of the pump. It serves as the interfacing medium between the non-rotating swash plate and the barrel. Furthermore, pistons have a spring-like system that can reshape their size when the barrel revolves. The non-rotating swash plate is the interface for the external system and pistons. As the pistons reshape themselves, they get compressed under the force of the swashplate. Lastly, the shaft is coupled to the rotating barrel and the swashplate, and it also houses the entire assembly.

How It Works

A piston pump operates on the principle of positive displacement. An electric motor or engine powers the crankshaft. As the crankshaft is supplied with power, it turns and delivers its rotary motion to the connecting rod. Then, the connecting rod transforms the motion into reciprocating motion and sends it to the piston, allowing it to move in a downward direction to create a vacuum inside the pump cylinder. As a result of the vacuum, there is a pressure difference between the cylinder’s inner pressure and outer pressure.

As the inner pressure becomes lower than the pressure of the reservoir, the inlet valve opens, allowing fluid to enter the cylinder. When the suction process is done, the inlet valve closes, and the piston moves upward to pressurize the fluid. This upward motion causes the cylinder’s inner area to decrease due to the compressed fluid. During the compression process, the fluid’s pressure and temperature becomes very high. Once the fluid pressure reaches the desired pressure, the discharge valve opens and fluid is transferred to the intended place. After the first stroke of the piston, the crank forces the piston downward and the process repeats itself.

Piston Pump Types

There are four types of piston pumps, those of which include lift, force, axial, and radial variations. However, this section will only outline how lift and force piston pumps operate. 

Lift piston pumps operate by drawing fluid from the suction valve to the bottom of the cylinder. During the upward stroke, the piston moves up and creates suction, causing fluid to enter the cylinder via the valve. During the downward stroke, the piston moves down and creates pressure on the fluid. At the same time, the valves allow fluid to pass through the piston to the other side. A last upward stroke forces the fluid in the upper part of the cylinder out while fluid is drawn into the lower part.

With force piston pumps, the piston’s upward motion sucks fluid into the cylinder through an inlet valve. Once the compression process is complete, the downstroke releases the fluid from the pump into the discharge pipe via an outlet valve. Force pumps only require one upward stroke to suck the fluid and one downward stroke to discharge it.

Advantages and Disadvantages

In terms of advantages, piston pumps can operate under a wide range of pressures. More than that, they can move slurries and high viscosity fluids. They do not require priming and are more efficient than plunger pumps.

With regard to disadvantages, these pumps provide a pulsating fluid which may not be ideal for all applications. Additionally, they have lower power than centrifugal pumps, and they have a high maintenance cost.


NSN Supplies is a leading distributor of piston pumps, sensors, industrial processing devices, and more. With over 2 billion items in our inventory, fulfilling your operational requirements is simple. Kickoff the procurement process with a competitive quote and see how NSN Supplies can serve as your strategic sourcing partner!


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