Table of Contents
Advertisement
RE 50170/12.10 HAB
Application, mode of operation
Applications
Hydro-pneumatic accumulators offer versatile applications:
– Energy storage for saving pump drive power in systems
with intermittent operation.
– Energy reserve for emergencies, e.g. in case of hydraulic
pump failure.
– Compensation of leakage losses.
– Shock and vibration absorption in periodic vibrations.
– Volume compensation in case of pressure and tempera-
ture changes.
V
0
p
0
Calculation
Pressures
In the accumulator calculation, the following pressures are of
vital importance:
p
= Gas filling pressure at room temperature
0
and drained fluid chamber
p
(t )
= Gas filling pressure at operating temperature
0
p
(t
) = Gas filling pressure at max. operating temperature
0
max
p
= Minimum operating pressure
1
p
= Maximum operating pressure
2
In order to achieve the best utilization of the accumulator vol-
ume possible as well as long service life, compliance with the
following values is recommended:
p
(t
)
0.9 p
(1)
0
max
1
Mode of operation
Liquids are almost incompressible and are therefore not able
to store pressure energy. In hydro-pneumatic Rexroth accu-
mulators, the compressibility of a gas is used for the fluid stor-
age. You may only use nitrogen of cleanliness class 4.0!
N
Charge
V
1
p
1
Discharge
The largest hydraulic pressure is not to exceed four times the
filling pressure as otherwise, the bladder elasticity is greatly
strained and excessive compression changes with consider-
able gas heating result:
The accumulator bladder service life is the longer the smaller
the difference between p
the reduction in the corresponding degree of utilization of the
maximum storage capacity.
Hydraulics Bosch Rexroth AG
= 99.99 vol. %
2
Charge
Discharge
(2)
p
4 • p
2
0
and p
1
5/18
V
2
p
2
. This, however, results in
2
Hide quick links:
Advertisement
Table of Contents
