Hydraulic Pump Basics

Pumps are devices that move fluids by applying mechanical force. There are many types of pumps, but they can be classified into two main categories: dynamic pumps and positive displacement pumps.

Dynamic pumps use kinetic energy or momentum to move fluids. They have a rotating or oscillating part that creates a pressure difference between the inlet and outlet of the pump. Some examples of dynamic pumps are centrifugal pumps, axial flow pumps, mixed flow pumps, jet pumps and electromagnetic pumps.

Positive displacement pumps use mechanical force to displace a fixed amount of fluid per cycle. They have a moving part that creates a sealed chamber with the inlet and outlet of the pump. Some examples of positive displacement pumps are reciprocating pumps, rotary pumps, screw pumps, progressive cavity pumps and gear pumps.

Gear pumps are a type of positive displacement pump that use meshing gears to pump fluid by displacement. They are one of the most common types of pumps for hydraulic fluid power applications. Hydraulic fluid is a liquid that transmits power in hydraulic systems.

Gear pumps have two gears that rotate in opposite directions. As the gears rotate, they separate on the intake side of the pump, creating a void and suction which is filled by fluid. The fluid is then trapped between the teeth of the gears and the casing of the pump. As the gears mesh on the discharge side of the pump, they push the fluid out of the pump.

Gear pumps are simple, compact and reliable. They can handle high pressures and viscosities, and they produce a smooth and constant flow of fluid with little or no pulsation. However, gear pumps also have some disadvantages. They are not suitable for abrasive or corrosive fluids, as they can cause wear and damage to the gears and seals. They also have a limited range of flow rates and efficiencies, and they can generate noise and vibration.

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Peristaltic Pump

Peristaltic pumps are a type of positive displacement pump that use a flexible tube to move fluids without exposing them to contamination. They are also known as roller pumps or tubing pumps.

Peristaltic pumps work by squeezing a section of the tube with a rotating mechanism, creating a vacuum that draws fluid into the tube. As the mechanism moves along the tube, it pushes the fluid ahead of it, creating a continuous flow. The tube returns to its original shape after being released, allowing more fluid to enter.

Peristaltic pumps have several advantages over other types of pumps. They are self-priming, which means they can lift fluids from a lower level without needing a suction valve. They can handle fluids with high viscosity, solids, abrasives, corrosives or sensitive substances without damaging them or the pump components. They are easy to clean and maintain, as only the tube comes in contact with the fluid.

Peristaltic pumps also have some limitations. They have a lower flow rate and pressure than other positive displacement pumps, such as gear pumps or piston pumps. They can cause pulsation or shear stress in the fluid, which may affect its quality or properties. They can also wear out the tube over time, requiring frequent replacement.

Peristaltic pumps are widely used in various industries and applications, such as food and beverage, pharmaceutical, chemical, water treatment, mining and biotechnology. They are ideal for pumping fluids that require hygiene, accuracy or gentle handling.

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