Disadvantages of pilot oil accumulator

What are the disadvantages of gas-charged accumulators?

A main disadvantage of gas-charged accumulators is that they are not suitable for high pressure and large volume. Additionally, they lose pressure as fluid discharges because the nitrogen gas must expand to push fluid out.

What are the disadvantages of a weight-loaded accumulator?

The main disadvantage of a weight-loaded accumulator is its physical size. An accumulator for the circuit shown in Figure 1-49 would require a 10-in. ram with a 60-in. stroke for the cylinder to have full force for its entire cycle. This size accumulator needs almost 160,000 lb of weight on the ram to get the required volume and pressure stated.

Why do gas-charged accumulators lose pressure?

All gas-charged accumulators lose pressure as fluid discharges because the nitrogen gas was compressed by incoming fluid from the pump and the gas must expand to push fluid out. A main disadvantage of this design is that it is not good for high pressure and large volume.

What is a problem with air cylinder loaded accumulators?

Physical size can also be a problem with air-cylinder-loaded accumulators, especially when using low air pressure. Most plant systems operate at 100 to 125 psi so the unit required to handle the cylinder in Figure 1-50 might be a 40-in. bore air cylinder driving a 9-in. ram with a 75-in. stroke.

What happens when oil accumulator discharges?

At this point, the accumulator relief/unload/dump valve is open, draining pressurized oil stored in the accumulator. As fluid in the accumulator discharges, pressure at gauge PG1 starts dropping. By controlling the flow with a fixed orifice or a flow control, pressure deteriorates slowly when there is oil in the accumulator.

Does a weight-loaded accumulator lose pressure?

A weight-loaded accumulator, as shown in Figure 16-1, does not lose pressure until the ram bottoms out. Thus, 100% of the fluid is useful at full system pressure.