Perhaps we should begin with why checking your hydraulic accumulator pressure is important.
It’s important because the variety of functions, including maintaining pressure and reducing pressure surges, reducing vibrations and storing energy in a similar way to a rechargeable battery, are all essential to the practical and safe running of the hydraulic system.
Now we know the why, we can get to the how in this step-by-step guide on how to check hydraulic accumulator pressure.
Understanding Hydraulic Accumulators
Hydraulic accumulators hold and compress nitrogen. They have either a piston or a membrane within a sealed container attached to the pump or hydraulic system.
There are three main functions of hydraulic accumulators; dampening the pulsation and vibration, pressure stabilisation, including if there is a leak or a peak in the system, and as a power source – especially in an emergency.
There are also three main types of hydraulic accumulators; a bladder accumulator, a diaphragm accumulator and a piston accumulator.
Bladder accumulators are the most commonly used type of hydraulic accumulator and are great for dampening high system pressure spikes.
Diaphragm accumulators are often used in very high-pressure systems and those with high cycle demands.
Piston accumulators are completely adaptable and are commonly used in custom-built hydraulic systems because they can be made to cope with high volume, high flow rate and any accumulator size.
Safety Precautions
Working with hydraulic systems and hydraulic accumulators can be hazardous and should only be attempted by those who are experienced and qualified to do so.
PPE (personal protective equipment) such as safety goggles and gloves must be worn at all times when working with the hydraulic system pressure.
Step-by-Step Guide on Checking Hydraulic Accumulator Pressure
It is advisable to check accumulator pressure at least monthly by following the below steps:
1. Locating the Accumulator & Pressure Gauge
Check the hydraulic system manual to locate the accumulator gas valve and its associated pressure gauge.
2. Releasing System Pressure
When the system is pressurised to a normal level slowly drain the hydraulic fluid or oil and watch the system pressure gauge needle carefully.
When it reaches the pressure drop point, the needle will suddenly drop to zero after going down at a steady rate until this point. Where the needle was pointing to on the pressure gauge, before the pressure drop point, shows the precharge pressure and charge pressure.
3. Analysing & Adjusting the Pressure
If the gas pressure reading shows a 10% variation in what it is supposed to be, it will need to be charged using a charging kit or charging rig. The minimum working pressure will vary between hydraulic systems – always familiarise yourself with the pre-charge pressure and maximum system pressure for the particular system you are working on.
Conclusion
Always ensure your hydraulic systems are checked at least monthly and that an experienced and qualified person carries out the checks. Following the instructions for the particular system you are using is also of paramount importance.