Service Life - HYDAC International SK210 Instrucciones De Servicio

5.3 Testing the pre-charge
pressure
The pre-charge pressure (p
with or without the FPU charging and testing
unit.
On small hydraulic accumulators, and wherever
possible, the pre-charge pressure (p
be tested without the charging and testing unit
to avoid any nitrogen loss during the test.
NOTICE
For drawings referred to in the text, see
fold-out page.
Testing without the charging and
testing unit FPU-1
If the hydraulic accumulator is set up as per the
fold-out page or by using the safety and
shut-off block (SAF or SAB), the pre-charge
pressure (p ) can also be checked via the fluid
0
side.
EN
– Isolate hydraulically charged piston
accumulator with shut-off valve  from the
system.
– Use pressure relief valve  to slowly drain
the piston accumulator on the fluid side.
– Watch the pressure gauge .
– The pressure will initially fall slowly. It will
drop suddenly only after the hydraulic
accumulator has drained completely. This
pressure is the same as the pre-charge
pressure (p
0
– If the indicated pre-charge pressure (p
differs from the nominal pressure, it must be
corrected where possible, see section 4.3.
Testing with the charging and testing
unit FPU-1
To test and charge using the charging and
testing unit FPU-1, see section 4.3.
34
) can be tested
0
0
) of the piston accumulator.
5.4 Checking for oil leakage on
the gas side
When the hydraulic accumulator is operated
fast and continuously, oil can leak through the
piston seals into the gas side. This can be
detected as follows:
– A loss of power of the machine or system
) should
– A higher gas pre-charge pressure than
before
– Escape of oil or oil mist when loosening the
hex screw (210)
NOTICE
The oil must only be removed by
appropriately qualified persons. Detailed
instructions are available on request.

6. Service life

Like all pressure vessels, piston accumulators
have a finite service life. The service life is
dependent on the cyclic test pressure and on
the number of load reversals.
The permitted load reversals are specified in
the Declaration of Conformity. The authorised
representative can use this data to determine
the operating life of the piston accumulator
(housing strength) depending on the operating
conditions of the hydraulic system.
)
0