types of hydraulic pump

Different Types of Hydraulic Pumps

A hydraulic pump is a mechanical device used in hydraulic systems for converting mechanical power to hydraulic energy. They work by pushing large amounts of hydraulic fluid through a cylinder or motor. Different types of hydraulic pumps are capable of generating different types of liquid pressure.

Hydraulics is a flexible and efficient form of energy transfer. Many modern machines and devices make use of innovative hydraulic pump technology as their source of power.

There are several types of hydraulic pumps that are used in various kinds of equipment and machinery. The three most common types of hydraulic pumps are gear pumps, piston pumps, and vane pumps. However, there are other kinds of pumps as well. They are hydraulic pumps with a clutch, hydraulic pumps with a dump valve, and hydraulic pumps used for refuse vehicles such as dry valve pumps.

In this article, we’ll look into the different types of hydraulic pumps their features, and their applications.

Working principle of hydraulic pumps

The principle of operation of the hydraulic pump is based on the method of displacement which involves the use of mechanically sealed chambers to transport fluid from the inlet or suction port to the outlet or pressure port.

Types of Hydraulic Pumps

There are generally 2 categories of hydraulic pumps – fixed displacement pumps and variable displacement pumps. The following are the most used type of hydraulic pumps:

  1. Vane Pump
  2. Gear Pump
  3. Piston Pump
  4. Clutch Pump
  5. Dump Pump
  6. Refuse Pump, and
  7. Screw Pump

1. Vane pumps

A vane pump has a cartridge that is located inside a housing. The input shaft of the pump is attached to the back of the cartridge. The output shaft of the pump is connected to the front of the cartridge. The rotating of the input shaft of the pump causes oil to be pumped. The more that the input shaft rotates, the more that oil will be pumped out of the pump. In a vane pump, the vanes are on the cartridge. When the input shaft rotates, the vanes change the area of the cartridge.

These are hydraulic pump that operates with low flow pulsation. Vane pumps produce less noise. They have low-pressure capability. The Vane pump produces a relatively high speed of up to 3,600rpm at a hydraulic pressure of 300ba. They have usually used injection molding and die casting machines applied by several industries as well as land and road construction companies.

Vane pumps come in different types:

  • Variable displacement
  • Fixed displacement
  • Single dension vane pump
  • Double dension vane pump and
  • Triple dension vane pump.
Hydraulic Vane Pump
Hydraulic Vane Pump

Advantages of Vane pumps

    • Operationally quiet
    • They have a moderate efficiency
    • They come with many control options

Disadvantages

    • Gives off much heat waste

2. Gear pumps

Gear pumps are hydraulic pumps with a simple design and widespread availability. They are employed in many hydraulic systems due to their design and working operation. Gear pumps have only a few moving parts and operate at a pressure of up to 210 bar. They are fixed displacement, also called positive displacement pumps. The same volume of flow with each rotation of the pump’s shaft is produced. The displacement chambers in a gear pump are formed between the rotating gear wheel and the housing of the hydraulic pump.

Different types of gear pump available include:

  • External gear pumps
  • Internal gear pump
  • Screw spindle jump
  • Gear ring pump.
Hydraulic Gear Pump
Hydraulic Gear Pump

Applications: The gear pumps most commonly used in open center hydraulic systems are the gear pump, the vane pump, and the lobe pump. Gear pumps come in a wide range of sizes. The smaller ones will be used in engine systems with low pressures and low horsepower needs. The larger sizes are used in high-pressure applications.

Advantages of Gear pumps

    • They are easy to install
    • Economical
    • Reliable when in use

Disadvantages

    • Relatively lower efficiency
    • They give off noise during operation

3. Piston pumps

Hydraulic piston pumps are used when high operating pressures are required, these types of hydraulic pumps deal with higher pressure than gear pumps in the same displacement. Reciprocating pistons are used to alternately generate suction and flow discharge. However, its limitation is the higher cost of acquisition and it is usually susceptible to contamination. Some designs of vane pumps are capable of 95% efficiency. Piston pumps are designed to withstand higher pressure than gear or vane pumps.

There are two types of piston pumps:

  • Axial piston pump and
  • Radial piston pump.
Hydraulic piston pump
Hydraulic piston pump

Advantages of Piston pump

  • They are highly efficient
  • Used to generate suction and flow discharge
  • Can withstand higher pressure

Disadvantage

  • They are expensive
  • Susceptible to contamination

7. Screw pump

This type of pump is a fixed displacement pump that is widely used in hydraulic systems. It features two screws that are interconnected and are enclosed inside a single chamber. Screw pumps are used in onboard ships with a hydraulic pressure system. They are used for high flows with relatively low pressure. They are used in controlling ball valves and also to help drive the steering and other parts. They give a low sound level but have a low-efficiency level. The hydraulic transition is also usually transmitted in an opposing direction to the flow.

Advantages of Screw pump

    • Quiet operation

Disadvantages

    • Low efficiency
hydraulic Screw pump
hydraulic Screw pump

FAQs

Which is the most efficient hydraulic pump?

A piston pump that works at almost 95% efficiency is widely regarded as the most efficient hydraulic pump. It has high efficiency of converting input mechanical energy into hydraulic energy. The overall efficiency of a hydraulic pump is obtained by multiplying the volumetric efficiency by mechanical efficiency. A piston pump does on not only deliver a high efficient pump but also gives off less waste heat

What is a 2-stage hydraulic pump?

A 2-stage hydraulic pump is a hydraulic pump that essentially contains 2 pump sections. It has an internal pressure-sensing valve that cuts over between the two pump sections. One section of the pump helps to generate flow at lower pressure while the other section helps to generate higher pressure at a lower pressure. 2-stage hydraulic pumps are usually employed in log splitters for retracting the piston into the cylinder.

What is the advantage of hydraulic pumps over other types of pumps?

Hydraulics is more advantageous than electric and gas pumps in that they have lower weight and high capabilities. Hydraulic units are generally powered by a significantly smaller motor that weighs less than the motors used in electric machines. Hydraulic pumps usually come with better system designs, modern technological components, and greater augmentation for the energy efficiency of machines. Also, the design of the hydraulic pumps functions in a more energy-efficient manner. This makes them the choice of use in many commercial industries.

Conclusion

Hydraulic pumps are now widely used in different industries to maximize performance, due to their high efficiency. There are several types of hydraulic pumps, with vane pumps, piston pumps, gear pumps, and screw pumps dominating the market. Hydraulic pumps play an integral role in maintaining precision and required force for most systems. Some of their areas of application include the manufacturing of construction equipment, cranes, trucks, tractors, hand tools, and so on.

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