Hydraulic Accumulators Flashcards
Hydraulic accumulators are often used as a protection against failure of the _____________.
oil supply
When the power brakes on large machines, If the system oil supply fails, the _________________ traps enough oil for several brake applications, thus providing emergency braking
accumulator
How does a hydraulic accumulator absorb shock?
Accumulators take in excess oil during peak pressures and let it out again after the surge is past.
Why would an accumulator use a gas instead of a fluid?
Fluids do not compress, but gases do compress.
This means you can charge the oil and to provide a cushion for shock loads.
Pneumatic means operated by _________________
compressed gas.
In pneumatic accumulators, the gas is separated from the oil by: _____________
a piston, a bladder, or a diaphragm
What is the function of the a piston, a bladder, or a diaphragm in a pneumatic accumulator?
This prevents mixing
of the gas and oil and keeps gas out of the hydraulic system.
Some accumulators used for ______________ or fairly static applications do not have a
separator between the gas and oil.
low-pressure
In a piston-type accumulator, a free-floating piston separates the _________________
gas from the oil
In a piston-type accumulator, a bleed hole is needed to make certain the _______________
top O-ring is lubricated.
In a ____________-type accumulator, a flexible bag made of synthetic rubber contains the gas and separates it from the hydraulic oil.
bladder-type
In a bladder-type accumulator, when system hydraulic oil pressure drops, protection is needed to prevent the bladder from being forced into the oil passage. How is this prevented?
To prevent damage to the bladder, a valve, a protective button, or a screen is used.
The ______________ is the gas pressure in the accumulator before
any oil is admitted.
precharge
The accumulator will not accept oil until the hydraulic pressure exceeds the _______________
gas pressure.
You should never fill an accumulator with __________or _________
oxygen or compressed air
Why should you never fill an accumulator with oxygen?
An explosion could result if oil and oxygen mix under pressure.
Why should you never fill an accumulator with compressed air?
An explosion could result if oil and oxygen mix under pressure. and
When air is compressed, water vapor in the air condenses and can cause rust. This in turn may damage seals and ruin the accumulator.
Always fill an accumulator with _____________. This gas is inert and free of both water vapor and oxygen.
dry nitrogen
Never charge an accumulator to a pressure more than ______________
that recommended by the manufacturer.
Before removing an accumulator from a hydraulic system, _________________
release all hydraulic pressure.
Before you disassemble an accumulator, ____________
release both gas and hydraulic pressures.
When you disassemble an accumulator, make sure that dirt and abrasive material does not _______________
enter any of the openings.
Before Removing Accumulator From Machine be sure all hydraulic pressure is released. To do this ______________
Shut down the pump and cycle a priority function within the hydraulic circuit that contains the accumulator until all pressure is relieved.
Why is air not recommended for use in a pneumatic accumulator?
An explosion could result if oil and oxygen mix under pressure. and
When air is compressed, water vapor in the air condenses and can cause rust. This in turn may damage seals and ruin the accumulator.
What are the four major uses of accumulators?
- Store energy
- Absorb shock
- Provide emergency power
- Maintain system pressure
