HYDAC International SBO Série Mode D'emploi page 44

4. Commissioning
NOTE
Diaphragm accumulators must be charged
with nitrogen. Check before commissioning
(see section 5.3).
The closing elements (e.g. protective plugs) on
the fluid side must be removed. The min./max.
operating data is permanently marked on the
accumulator. The marking must be kept in a
legible condition.
4.1 Pre-charge pressure
Diaphragm accumulators are normally supplied
with a transit pressure of approx. 2 bar. If
required, the accumulator can be supplied pre-
charged to the customer's required pressure
setting. The pre-charge pressure (p
indicated on a label on the accumulator body,
or stamped on the accumulator body.
The accumulator must be charged by the
operator to the required pre-charge pressure
before commissioning. The level of pre-charge
pressure is calculated from the operating data
of the system.
NOTE
GB
If the pre-charge pressure is too high the
all-PTFE diaphragm can become damaged.
Critical values of the pre‑charge
pressure
Diaphragm accumulator
SBO with all-PTFE
diaphragm
SBO330-1 l
SBO250-1 l and
SBO250-2 l
all sizes > 2.8 l
SBO...-2.8 l
other sizes < 2.8 l
all screw-type designs
Torque value of the int. hex. screw (1) 20 Nm.
44
4.2 Charging gas
Hydraulic accumulators must only be charged
with nitrogen class 4.0 minimum. Deviations
from these specifications must be agreed with
HYDAC.
4.3 Charging the accumulator
The HYDAC FPU charging and testing unit
must be used to charge the diaphragm
accumulator.
The charging and testing unit is supplied with
detailed operating instructions.
During the charging process the accumulator
must be securely mounted. See also section
5.3 of this manual.
4.4 Permitted operating
) is
The permitted operating temperature is
0
determined by the material of the accumulator
body, diaphragm and seal, and is indicated
on the stamped marking and the certificate of
conformity.
4.5 Permitted operating pressure
The permitted operating pressure is determined
by the material of the accumulator body and
is indicated on the stamped marking and the
certificate of conformity.
4.6 Hydraulic fluids
Hydraulic accumulators must only be operated
with hydraulic fluids to a minimum cleanliness
level of:
– NAS 1638 Class 6 or
Permitted
– ISO 4406 Class 17/15/12.
pressure ratio
p : p
4.7 Installation position
max 0
2 : 1
Diaphragm accumulators must preferably be
p ≤ 200 bar
installed vertically, with the gas valve at the
0,t max
top. Other installation positions are possible.
However, performance may be impaired.
4 : 1
Irrespective of the installation position, the
marking on the accumulator as shown on the
type code label or accumulator body must be
6 : 1 (4 : 1)
accessible and legible.
8 : 1
Allow an area of approximately 150 mm x 150
10 : 1
mm above the gas charging connection for
fitting the charging unit.
temperatures