Hydac SK Series, Operating Instructions Manual

Page: 44 / 97

GB
44
INT 3.301.BA4/05.16
4.4 Permitted operating
temperatures
The permitted operating temperature is
determined by the material of the accumulator
shell and the seal, and is indicated on the
name plate and the certificate of conformity.
4.5 Permitted operating pressure
The permitted operating pressure is determined
by the material of the accumulator shell, and is
indicated on the name plate and the certificate
of conformity.
4.6 Hydraulic fluids
Hydraulic accumulators must only be operated
with hydraulic fluids with a minimum cleanliness
class of:
– NAS 1638 Class 6 or
– ISO 4406 Class 17/15/12.
4.7 Installation
Piston accumulators can be installed in any
position. However, the vertical position with the
gas valve at the top is required for certain
position indicating systems.
Irrespective of the installation position, the
marking on the accumulator as shown on the
name plate or accumulator shell must be
accessible and legible.
Allow an area of approx. 150 mm x 150 mm
above the gas valve for fitting the charging unit.
4.8 Earthing
The piston accumulator must be earthed.
4.9 Mounting
The piston accumulator must be installed
securely to withstand vibrations during
operation or any break in the connection lines.
Also, the mounting elements must not exert
stress in any form on the piston accumulator.
For suitable clamps and consoles please refer
to the brochure "Supports for Hydraulic
Accumulators", no. 3.502.
4.10 General
For further technical details please refer to the
following brochures:
"Piston accumulators", no. 3.301 and
"Piston Accumulators Series SK280",
no. 3.303.
4. Commissioning
NOTE
Before commissioning and after charging the
accumulator to the required pre-charge
pressure, check that the connections on the
fluid and gas side are tightened to the correct
torque, and tighten further if necessary. It
must be ensured that no attachment parts
become twisted.
For tightening torques, see fold-out page.
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. Piston accumulators must be
charged with nitrogen. Check before
commissioning (see section 5.3).
If bleeding is required, this must be done prior
to commissioning, on the oil-side connection.
4.1 Pre-charge pressure
If required, the accumulator can be supplied
pre-charged to the customer's required
pressure setting. The pre-charge pressure (p
0
)
is indicated on a label on the accumulator shell,
or stamped on the accumulator shell or
engraved on the name plate.
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.
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 piston 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.