What Is An Accumulator?

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Video Transcript

Hi everybody. Welcome to white papers on whiteboard. My name is Miguel Vita. I work for Freudenberg in the hydraulic accumulator division. I was invited today by our partners ESP International to talk about hydraulic accumulators.

We decided to start with the basics:

What is an accumulator?

How can I use an accumulator?

What are the different technologies that we have on an accumulator?

What Is An Accumulator? The Basic Principle.

What Happens On The Hydraulic System?

Basic Functions Of An Accumulator

1. Starting with the pulsation dampening. On the hydraulic system, you have pulsation. This pulsation is coming basically from the hydraulic pumps. So the accumulator will make a dampening on this pulsation and will stabilize your system. You’ll reduce the noise, you’ll reduce the vibration of the system and you’ll have the system working this move.
2. Also, the accumulator can keep constant pressure in your system. If you have a leakage, for example, you’re going to lose the pressure of the system. The accumulator will stabilize the pressure and you keep the pressure at a certain level until you can stop your system for maintenance.
3. Another function of the accumulator is really to be an emergency source of power in your system. For example, when you have your system being applied on hydraulic brakes and you need a sudden release of pressure in your system, the accumulator will help you release this pressure whenever it is needed.

Three Types of Accumulators

And here we come to the three different types of accumulators. We have the bladder, diaphragm, and the piston type of accumulators.

1. Bladder Accumulator

The Bladder is the bread-and-butter. You can use bladder accumulators everywhere. Most of the hydraulic systems use bladder accumulators.

• You have a bladder bag.
• You have the pre-charge of nitrogen.
• Connected to the hydraulic system.

Those accumulators are used in pulsation dampening where you have high frequency, especially in a small amplitude. A lot of applications, right? But this type of accumulator has a restriction. The bladder has a vulcanized seam, and this is the weak point of the bladder system. If you have high frequency and high cycle demand, you can have a rupture in this seam. This is the restriction of this type of accumulator.

2. Diaphragm Accumulator

Then we can go to the diaphragm type accumulator.

• Basically, the same where you have a carbon steel shell but instead of a bladder, you have a diaphragm.
• Also, the pre-charge of nitrogen and this portion is connected to the system.

Very similar applications as the bladder type accumulator. However, the diaphragm accumulator has an advantage.

Since you don’t have a seam in the diaphragm, you don’t have the restrictions that you have with the bladder type accumulator.

So applications pretty much the same, but this one is really a reliable accumulator, especially when you have high cycle demands. Applications with 1 million, 2 million, 3 million cycle demands – this is where to use a diaphragm accumulator.

3. Piston Accumulator

• Instead of a bladder or a diaphragm, we are using an aluminum piston to make a barrier with the nitrogen.
• You keep the nitrogen pre-charged.
• The system is connected to your hydraulic system.

But really you don’t have limits for this type of accumulator.

Since you machine the accumulator, you can make it in any size. You can make accumulators with a quarter gallon. You can make accumulators with 300 gallons. You can make accumulators going to 40,000 PSI.

Custom ports, custom design, and materials so the piston accumulator is really for limited applications where you can make custom design accumulators.

Thank you.