Understanding and Maintaining Hydraulic Accumulators

Blog | July 27th, 2022

Accumulators for hydraulic fluid may be found in virtually every type of manufacturing facility. The majority of establishments have more than one of them, yet the majority of the time, they are misinterpreted. Not because they are intrinsically harmful, but rather due to a lack of understanding, accumulators can be the most dangerous hydraulic components in the mill. This is not because accumulators themselves are dangerous. Accumulators in hydraulic systems serve a variety of purposes, but ultimately, they all store energy, thus it is imperative that they be handled with at least some degree of reverence.

Its Various Functions

Either to add volume to the system at a very rapid pace or to absorb shock is one of the uses that a hydraulic accumulator may be put to. These are the two primary functions of an accumulator. The amount of charge it has stored determines which function it will carry out. If the accumulator is going to be utilised to add volume to the system, the pre-charge of the accumulator has to be somewhat lower than the maximum pressure of the system so that oil may enter it. If the accumulator is going to be used to absorb shock, it has to be pre-charged to a pressure that is near to the utmost that the system can handle. This will ensure that there is very little oil, if any, in the device.

Importance of Pre-Charging It

Most of the time, dry nitrogen is used to pre-charge an accumulator. Nitrogen doesn’t react badly with hydraulic oil under pressure, and since it makes up about 78% of the earth’s atmosphere, it is the safest and least expensive gas to use. The next most common non-reactive gas is argon, which makes up less than 1% of the atmosphere of the earth.

An accumulator should be pre-charged with a charging rig. When you do the pre-charge, there should be no oil in the accumulator. Let out any pressure at the inlet of the accumulator. Most batteries have a valve that can be opened to let oil flow into the tank. Attach the charging rig to the Schrader valve on the accumulator and push down on the pin by turning the gas chuck handle clockwise. The charging rig can then show how much pre-charge is left.

The right amount of pre-charge depends on the use and type of accumulator. The bladder, piston, and diaphragm types of accumulators are the most common. If the original equipment manufacturer (OEM) has any suggestions, you should follow them. If not, the right amount of the pre-charge can be guessed.

Most of the time, an accumulator fails because it was pre-charged too much. If the pre-charge is higher than it should be, the bladder in a bladder accumulator will hit the poppet assembly during each cycle. This can cut the bladder or cause the spring in the poppet to wear out faster than it should because of the stress. In piston accumulators, if the pre-charge is too high, it can hurt the piston and keep it from hitting the bottom of the cycle each time. Too low of a pre-charge (or an increase in system pressure without a corresponding increase in the pre-charge) can also cause problems with operation, like slowing down or stopping. It could even cause damage to the accumulator.

When Having it Mounted

A mounting bracket should be placed about two-thirds of the way up the accumulator’s shell when it is installed in a vertical position. The seals on a horizontally-mounted piston accumulator will wear out more quickly. If a bladder accumulator is positioned horizontally, it might potentially be damaged. A cavity that occurs between the bladder and the shell might prevent fluid from escaping the outlet and cause uneven bladder wear. Mounting a diaphragm accumulator is often flexible.

Mobile Hydraulic Specialties Pty Ltd

Factory 89, 38-40 Popes Road
Keysborough, Victoria, 3173

Phone: (03) 9798-6511

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Mobile Hydraulic Specialties Pty Ltd

Phone: (03) 9798-6511
Address: Factory 89, 38-40 Popes Road, Keysborough, Victoria, 3173