In various hydraulic applications, a brief surge of high flow is necessary, such as in a punch press. Hydraulic accumulators can effectively supplement pump flow to meet this requirement. For instance, a punching operation may require 20 gallons per minute (gpm) over 10 seconds to achieve the desired cycle speed, but if the pump’s output is only 5 gpm, this velocity cannot be reached with the pump’s power alone. During the 50 seconds of idle time between press functions, the 5 gpm pump can store energy in the accumulator, ensuring the system is ready for the high-speed press function when needed. By using accumulators to enhance pump flow, energy is conserved, allowing for the use of a smaller pump while still meeting higher demand.
This same setup can be applied to control intermittent actuators, like clamps, which require less than the previously mentioned 20 gpm. For example, if a clamp cylinder needs just 5 gpm for five seconds every minute, the power unit can be controlled via a pressure switch installed downstream of a check valve. The accumulator will store enough energy for several clamp functions before it runs low, at which point the pressure switch will activate the power unit until the system regains full pressure, turning it off again. Another application of this circuit is to maintain pressure at an actuator; the clamp can remain engaged with the directional valve activated while the accumulator compensates for any leakage or decay within the circuit components.
Automotive Lift Repair Orlando Accumulators are sized for energy storage based on the flow required and the difference between maximum and minimum work pressures. The compression ratio of the accumulator is also an essential factor, as it indicates the recommended maximum ratio between minimum and maximum operations. A higher compression ratio enables greater fluid storage, with piston accumulators generally outperforming bladder types in this aspect.
The effectiveness of 10-gallon bladder and Automotive Lift Repair Orlando piston accumulators can be assessed through their compression ratios, working pressures, and required precharges. An optimal precharge is usually about 80% of the minimum working pressure. A precharge that is too high can prevent the accumulator from fully filling, while one that is too low limits energy storage. Additionally, a greater difference between maximum and minimum pressures increases energy capacity; for example, a drop from 5000 to 1000 PSI will yield more volume than a drop from 5000 to 4000 PSI.
Automotive Lift Repair Orlando Accumulators are also useful for mitigating pump pulsations and absorbing shock. Pump pulsations occur due to pressure waves created as gears, vanes, or pistons reach the outlet port in discrete bursts rather than a steady flow. These pulsations can lead to vibrations and noise, but a properly sized diaphragm-type accumulator can dampen these effects, providing smoother pump flow.
When working with hydraulic accumulators, it’s crucial to prioritize safety during setup and maintenance. Be aware of the potential hazards associated with charging accumulators and handle the cylinders carefully. Ensure that your charging equipment is in proper working condition and suitable for the task, as there are many different charge heads available. Always deplete the hydraulic energy stored in the accumulator before performing any service, typically achieved using accumulator safety valves or ball valves. Rapidly released stored energy can cause significant damage or injury if not managed properly.
Hydraulic accumulators are devices that store energy within a hydraulic circuit, functioning similarly to capacitors in electrical circuits. They serve various purposes in hydraulic systems, with the most common application being the rapid delivery of oil to extend and retract cylinders quickly. Accumulators can also absorb shocks, minimize noise, maintain pressure, and provide fluid in case of a power failure.
For Automotive Lift Repair Orlando accumulators designed to handle volume, they are typically pre-charged with dry nitrogen to about half to two-thirds of the maximum system pressure. For instance, if the system’s maximum pressure is set at 1500 PSI, the accumulator should be pre-charged between 750 and 1000 PSI. The pre-charge refers to the nitrogen pressure in the gas chamber of the accumulator when it contains no fluid. Depending on the design, gas-filled accumulators use a bladder, piston, or diaphragm to separate the dry nitrogen from the hydraulic fluid.
When there is no fluid pressure in the system, the dry nitrogen fills the Automotive Lift Repair Orlando accumulator completely, causing the bladder or diaphragm to extend fully or the piston to press against the fluid inlet cap. Once the pump is activated, the fluid pressure increases beyond the pre-charge pressure, compressing the nitrogen gas until the maximum system pressure, potentially reaching 1500 PSI, is achieved. For example, in a 10-gallon accumulator with a pre-charge of 750 PSI, there would be 5 gallons of fluid in the accumulator when the gas pressure hits 1500 PSI. When directional valves are engaged in the system, the combined pressure of the system and the accumulator will start to decline if the demand for fluid exceeds the pump’s output. In a bladder accumulator, the nitrogen compresses the bladder, forcing oil out, while in a piston type, the piston pushes against the fluid side, delivering a high flow rate to the system. Generally, the accumulator’s volume works in tandem with the pump volume to power the actuators.
Automotive Lift Repair Orlando Accumulators that are continuously operating in a system typically exhibit higher temperatures at the fluid end compared to the gas end. This temperature differential is a useful indicator of proper accumulator function. If the shell temperature is uniform, it may suggest a ruptured bladder, pre-charge pressure exceeding the compensator or relief valve settings, or nitrogen leakage from the valve stem. The heat difference will depend on factors such as the size of the accumulator, the frequency of cycles, and the volume being delivered. The accumulator can provide a portion of its rated gas capacity based on the pre-charge to system pressure ratio.
In addition to checking temperature variations, the accumulator’s performance can be assessed by monitoring the fluid pressure gauge when the system is turned off. Often, accumulators are equipped with manual or solenoid-operated valves to release fluid back into the tank when the system is inactive. As fluid exits the Automotive Lift Repair Orlando accumulator and flows back to the tank, the system pressure gradually decreases until all fluid is discharged. At this point, the pressure gauge will quickly drop to 0 PSI. The last reading before this drop closely resembles the pre-charge pressure.