From Practical Hydraulic Systems: Operation and Troubleshooting for Engineers and Technicians

7.5 Accumulators

Accumulators are devices, which simply store energy in the form of fluid under pressure. This energy is in the form of potential energy of an incompressible fluid, held under pressure by an external source against some dynamic force. This dynamic force can come from three different sources: gravity, mechanical springs or compressed gases. The stored potential energy in the accumulator is the quick secondary source of fluid power capable of doing work as required by the system. This ability of the accumulators to store excess energy and release it when required, makes them useful tools for improving hydraulic efficiency, whenever needed. To understand this better, let us consider the following example.

A system operates intermittently at a pressure ranging between 150 bar (2175 psi) and 200 bar (2900 psi), and needing a flow rate of 100 lpm for 10 s at a frequency of one every minute. With a simple system consisting of a pump, pressure regulator and loading valves, this requires a 200 bar (2900 psi), 100-lpm pump driven by a 50 hp (37 kW) motor, which spends around 85% of its time, unloading to the tank. When an accumulator is installed in the system as shown in Figure 7.12, it can store and release a quantity of fluid at the required system pressure.


Figure 7.12: Circuit diagram showing an accumulator

The operation of the system with accumulator is illustrated by Figure 7.13;


Figure 7.13: Graphical representation of accumulator operation

At time A, the system is turned...

Copyright IDC Technologies 2005 under license agreement with Books24x7

Products & Services
Web Accumulators and Coil Accumulators
Web accumulators and coil accumulators are used to control the tension of materials in continuous manufacturing processes.
Pressure Washers
Pressure washers direct a high-pressure stream or jet of water against a surface to clean, descale, degrease or prepare a surface.
Hydraulic Repair Services
Hydraulic repair services rebuild, repair and calibrate used hydraulic components and equipment such as hydraulic pumps, valves and servo valves, cylinders, motors, jacks, rams, actuators, hydraulic power units (HPUs) and hydraulic machines or systems.
Water Jetting Equipment and Water Blasters
Water jetting equipment and water blasters direct high pressure (10,000+ psi) streams of water against a surface to clean or cut the material.

Topics of Interest

7.6 Heat exchangers Heat is generated in a hydraulic system because of the simple reason that no component can operate at 100% efficiency. Significant sources of heat include pumps, pressure relief...

Accumulators are simple devices that store energy in the form of fluid under pressure. Because of their ability to store excess energy and release it when needed, accumulators are useful tools in...

Hydraulic-equipment designers are finding new ways to save energy and cut equipment costs. Senior Application Engineer Parker Hannifin Hydraulic Accumulator Div. Rockford, Ill. Hydropneumatic...

Accumulator-based energy recovery systems improve mobile-equipment efficiency. Hydropneumatic accumulators are widely used in industrial and mobile hydraulic systems because they provide auxiliary...

Nine university teams recently tested their engineering skills and racing prowess on fluid-powered bikes. The pneumato-bike from Univ. of California, Irvine, stored pressurized air in a series of...