Hydraulic Accumulators: Different Types And Their Applications

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Categories: Hydraulic

The purpose of hydraulic accumulators is simple as all they need to do is store energy in the form of fluid when under pressure. Accumulators basically store hydraulic energy in the form of pressurized fluid. The pump initially provides the fluid and later delivers it to the system whenever needed. 

This can be very useful in boosting the efficiency of your hydraulic systems as accumulators have the potential to store extensive energy and release the same when needed by the machine.

Different Types of Hydraulic Accumulators   

The classification of hydraulic accumulators is facilitated through the use of energy storage. That being said, there are currently three different types of hydraulic accumulators that include:

  1. Weight loaded accumulator
  2. Spring-loaded accumulator
  3. Gas loaded accumulator     

1. Weight Loaded Accumulator

Weight loaded accumulators are generally equipped with a piston loaded with a dead weight. Hence when the piston moves within the cylinder, this results in exerting pressure on the hydraulic fluid. Materials such as iron, concrete block or even steel are generally used as the dead weight.  

• Application Of Weight Loaded Accumulators

The bulk and size of weight-loaded accumulators limit their applications to stationery equipment that generally includes heavy-duty presses where large volumes are necessary.

2. Spring Loaded Accumulators

These are accumulator types that generally come with a spring-loaded piston in the cylinder. The fluid enters this accumulator from the other side of the cylinder and is stored under pressure by leveraging the force exerted by the spring.

When the spring is compressed optimally, the pressure also reaches its peak. Consequently, the pressures drop to a minimum as the spring reaches its entire length.  

• Applications Of Spring Loaded Accumulators 

These accumulators are generally used where space is a constraint, and the work is done in smaller volumes. This includes mobile and automotive hydraulic applications. 

3. Gas Loaded Accumulators 

Gas loaded accumulators, also called hydro-pneumatic accumulators, are further divided into two categories: non-separator type accumulators and separator type accumulators.  

(I) Non-Separator Type Accumulator

These are the types of accumulators where the entry of pressurized gas into the cylinder results in pressurization. Hence the increase in pressure ultimately results in opening the oil port, following which the oil enters the cylinders reducing the volume of gas. This further increases the pressure resulting in a pressure gap that drives the accumulator. 

Applications Of Non-Separator Type Accumulator

Such accumulators are used where the hydraulic fluid used in the system comes with a higher separate-ability. Therefore, the slightest missing of gasses does not result in any complications. 

II. Separator Type Accumulator 

Separator type accumulators are the ones where the piston works as a barrier between the hydraulic fluid and gas. Hence when the charged oil pushes the piston, it automatically results in gas compression.

This further means that reducing the volume of the gas will further increase the pressure. This gap in the pressure forces the oil out of the cylinder whenever needed in the circuit.    

 Furthermore, there are three different types of separator type accumulator that include: 

  • Bladder Type Accumulator: These accumulators leverage a bladder that functions as a flexible separator between the gas and the hydraulic fluid. The bladder will be fastened within a steel shell through the vulcanized gas valve assembly in any bladder type accumulator.
  • Diaphragm Type Accumulator: These accumulators use a diaphragm as an elastic separator where the diaphragm is thoroughly clamped between the pressure vessel walls.
  • Piston Type Accumulator: The piston will act as a separation between the oil and compressed gas in this accumulator. The construction of this accumulator is not much different from a spring-loaded accumulator except for one distinction where the spring is replaced with the pressurized gas.        

• Application Of Separator Type Accumulators

There are many applications of separator type accumulators, as the bladder type accumulator can be seen in a wheel suspension of vehicles.

Further, the diaphragm type accumulator can be seen when one requires high pressures with smaller volumes. Lastly, piston-type accumulators can be seen used in high-temperature systems where the volume requirements are more diminutive.  

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FAQs:

What are hydraulic accumulators?

Hydraulic accumulators are simple devices used to store hydraulic energy in the form of pressurized fluid delivered by the pump and later to the system whenever needed. 

Why is nitrogen used in accumulators?

Hydraulic accumulators use nitrogen to maintain the pressure of the hydraulic fluid. This means that when one pumps the fluid into the accumulator, this compresses the nitrogen in the accumulator. 

Should accumulators only be mounted in a vertical direction?

Certain hydraulic accumulators such as piston hydraulic accumulators or bladder accumulators must be mounted vertically. However, this is not a necessity for every accumulator as their working principles and applications might vary. 

How do hydraulic accumulators work?

Hydraulic accumulators are pressure vessels with varied applications in a hydraulic system. The accumulators collect the pressure fluid when the pressure rises, resulting in the gas being compressed and expanding again to push the fluid into the circuit. 

What is a hydraulic accumulator used for?

A hydac accumulator is used for varied purposes, including increasing the speed of the operating circuit, dampening periodic shocks and pulsations, reducing pressure peaks, powering the chassis suspensions, maintaining pressure, recapturing and storing hydraulic energy.