Accumulator Capacity Calculator

An accumulator is a metallic ball-like structure, internally separated into two compartments by a man-made rubber partition. The top compartment holds the system’s fluid under pressure, while the bottom compartment is filled with nitrogen or air.

A cylindrical variant of the accumulator is also utilized in high-pressure hydraulic systems. Multiple accumulators can be found in the hydraulic systems of numerous aircraft, including a primary system accumulator and a backup system accumulator. Additional accumulators may also be found in different subsystems.

Here is a more detailed explanation of the parts of the hydraulic accumulator in the image:

• Hydraulic system pressure: This is the pressure of the hydraulic fluid in the hydraulic system.
• Diaphragm: The diaphragm is a flexible membrane that separates the hydraulic fluid from the pressurized gas.
• Screen to prevent extrusion: This screen prevents the diaphragm from extruding through the gas servicing valve.
• Rigid button or disc to prevent extrusion: This button or disc also prevents the diaphragm from extruding through the gas servicing valve.
• Hydraulic fluid: This is the fluid that is stored and transported in the accumulator.
• Nitrogen or air: This is the pressurized gas that drives the hydraulic fluid out of the accumulator.
• Gas servicing valve: This valve allows the gas pressure in the accumulator to be adjusted.
• Retaining plug: This plug seals the gas servicing valve.

Accumulator Types

There are two main types of hydraulic accumulators: bladder accumulators and diaphragm accumulators. Both types work on the same basic principle, but they use different methods to separate the hydraulic fluid from the gas.

In a bladder accumulator, the hydraulic fluid is separated from the gas by a flexible bladder. The gas is usually nitrogen, which is an inert gas that does not react with the hydraulic fluid.

In a diaphragm accumulator, the hydraulic fluid is separated from the gas by a flexible diaphragm. The diaphragm is usually made of a synthetic rubber material.

The gas in the accumulator is pre-charged to a pressure that is higher than the operating pressure of the hydraulic system. This pre-charge pressure provides the force to push the hydraulic fluid out of the accumulator when needed.

Accumulators are used in a variety of hydraulic systems for a variety of purposes. Some of the most common uses for hydraulic accumulators include:

• To provide energy for auxiliary systems. Accumulators can be used to provide energy for auxiliary systems, such as brakes, steering, and winches. This can be useful in applications where the main hydraulic system is not always running.
• To absorb shock and vibration. Accumulators can be used to absorb shock and vibration caused by sudden changes in load or pressure. This can help to protect the hydraulic system from damage.
• To maintain system pressure. Accumulators can be used to maintain system pressure when the hydraulic pump is not running. This can be useful in applications where the hydraulic system must be able to operate even when the engine is not running.
• To smooth out flow pulsations. Accumulators can be used to smooth out flow pulsations caused by the hydraulic pump. This can help to improve the performance of the hydraulic system and extend the life of the components.

Accumulator Capacity Calculator

The calculations used in this calculator are based on ideal gas laws and assume that the gas and fluid are not interacting. In real-world applications, these assumptions may not be fully accurate, and additional factors like temperature, fluid compressibility, and gas-to-fluid ratio may need to be taken into account. 

Now, let’s describe each input in the formula:

1. BC (Accumulator Container Volume per capacity in gallons): This is the physical volume of the accumulator container. It can be found on the manufacturer’s specifications sheet or tag on the accumulator itself.
2. Pp (Pre-charge Pressure in psi): This is the initial gas pressure in the accumulator before any fluid is sent to it. The pre-charge pressure is usually set by the manufacturer and can often be found on the product specifications sheet. In some cases, it may be necessary to manually measure this pressure using a pressure gauge.
3. Ps (System Pressure in psi): This is the pressure of the system when it is running under normal operating conditions. In many cases, the system pressure is set by the pressure relief valve and can be found in the system’s operational manual or by using a pressure gauge.
4. Pf (Final Pressure in psi): This is the maximum pressure the accumulator will reach when it is fully charged. This value is set based on the system’s requirements and can be found in the system’s operational manual. In practice, it may be necessary to adjust the final pressure to account for changes in system demand or energy requirements.

Enter Accumulator Container Volume per capacity (gallons):


Enter Pre-charge Pressure (psi):


Enter System Pressure (psi):


Enter Final Pressure (psi):


Calculate

Hydraulic accumulators are an important component of many hydraulic systems. They provide a variety of benefits, such as improved performance, increased reliability, and reduced maintenance costs.