Hydraulic accumulator

Hydraulic accumulators, also known as hydro-accumulators, are key components used in hydraulic systems that enable the storage of liquid energy under high pressure. Thanks to their functionality and versatility, they are used in many industrial sectors, including construction, agricultural, production, and power machinery. At the Hydron store, we offer a wide selection of hydraulic accumulators characterized by the highest quality and durability, ensuring reliable operation even in demanding conditions. What are hydraulic accumulators and how do they work ?  Hydraulic accumulators are devices that store energy in the form of compressed gas (usually nitrogen) separated from the hydraulic fluid by a special membrane, diaphragm, or piston. This mechanism allows for the temporary storage and release of energy depending on the system's needs.

What are hydraulic accumulators used for ?

Hydraulic accumulators play a key role in improving the functionality and efficiency of hydraulic systems. Their main applications include: 1) Energy storage: They store excess energy while the system is operating under a lower load and release it when demand is higher. 2) Reduction of pressure fluctuations: They stabilize the pressure in the system, allowing for smoother and more reliable operation. 3) Damping of vibrations and shocks: They suppress sudden pressure spikes, protecting system components from damage. 4) Overload protection: They protect the system from the effects of a rapid increase in pressure that could damage hoses or equipment. What is the task of a hydraulic accumulator ? The main task of a hydraulic accumulator is to ensure optimal working conditions for the hydraulic system by: maintaining constant pressure in the system, enabling energy storage for use at peak load moments, reducing noise and vibrations associated with the operation of a hydraulic pump, protecting components from the effects of shocks and overloads.

What pressure should a hydraulic accumulator be set to ?

Correct pressure setting in the accumulator depends on the specific requirements of the given hydraulic system. Typically, the pre-charge pressure (of nitrogen) should be between 60% and 90% of the maximum operating pressure of the system. For example: If the maximum operating pressure is 200 bar, the pre-charge pressure in the accumulator should be set in the range of 120 to 180 bar. Exact values are recommended by the accumulator manufacturer or the hydraulic system designer.

How to charge a hydraulic accumulator ?

Charging a hydraulic accumulator is done by introducing compressed gas (usually nitrogen) using a specialized service kit. This process requires precision and appropriate equipment to ensure safety and proper operation of the device. Procedure steps: 1) Preparation: Make sure the accumulator is emptied of hydraulic fluid and disconnected from the system. 2) Service kit connection: Connect the accumulator to the pressure gauge and nitrogen cylinder using service hoses. 3) Pressure regulation: Gradually introduce nitrogen, monitoring the pressure value on the gauge until it reaches the appropriate level. 4) Control: After reaching the target pressure, check the tightness of connections and disconnect the service kit. Note: The charging process should be performed by trained specialists using appropriate equipment to avoid damage to the accumulator or danger to the user.

Types of accumulators 

We distinguish bladder, diaphragm, and piston hydro-accumulators. Hydro-accumulators are sealed pressure vessels storing working fluid under high pressure for use when needed. Most commonly used are hydropneumatic accumulators with a separator in the form of a piston (piston accumulators), a bladder (bladder accumulators), or a diaphragm (diaphragm accumulators) separating the gas from the liquid. They use gas compressibility to store energy and release it during moments of increased demand. They are widely used in hydraulic power units for industrial machinery and equipment, in vehicle suspension components, in concrete mixers, and working machinery. 

How to select a hydraulic accumulator ?

Selecting a hydraulic accumulator is a key stage in designing a hydraulic system. It requires considering system operating parameters such as pressure, stored fluid volume, or environmental conditions. Proper selection of the accumulator allows for efficient hydraulic energy storage, pressure stabilization, and improved system performance. Determining the application of the accumulator. First of all, it is necessary to define what function the accumulator will perform in the system.  Calculating accumulator capacity : The capacity of the accumulator depends on the amount of energy it must accumulate and the pressure range in the system. The following should be considered: Pre-charge pressure (P0): Minimum gas pressure in the accumulator before starting work. Operating pressure (P1 and P2): The range in which the accumulator will operate. P1 is the maximum pressure, and P2 is the minimum usable pressure. Fluid volume (V): The amount of fluid that the accumulator must accumulate in a given pressure range. The formula for calculating accumulator capacity is often based on the ideal gas law, e.g.:

V0=V(P1/P0)−(P1/P2)V_0 = \frac{V}{(P1/P0) - (P1/P2)}V0=(P1/P0)−(P1/P2)V

Where:

• V0V_0V0 – accumulator capacity,
• $V$ – required amount of fluid,
• $P0,P1,P2$ – pressure values.