Commissioning; Checks Before Commissioning; Gas Pre-Charge Pressure - Freudenberg BA 15-B02 000/18 Instrucciones De Operación

5. Commissioning

5.1. Checks before commissioning

Inspections prior to commissioning and recurring inspections must be carried out in accordance
with the national regulations.
Before commissioning, at least ensure that
•
the bladder accumulator is undamaged after installation.
•
all tubes are intact as well as the accumulator and tube connections are tightened.
•
the accumulator is well clamped and no additional tension is initiated to the vessel.
•
the max. allowable working pressure as well as the allowable working temperatures of the accumulator meet
the requirements of the machine or application in which the bladder accumulator is to be operated.
•
bladder and seal elastomers have sufficient chemical resistance to the operating fluid and the pressure
fluid meets the requirements of PED fluid group II.
•
the purity of the operating fluid (ISO 4406 class 17/15/12 or better recommended) is adequate.
•
the pre-charge pressure meets the requirements of the name plate.
Bladder accumulators are often shipped with a pre-charge pressure of approx. 0.5 - 2 bar for
preservation. The actual pre-charge pressure must always be double checked and, if necessary,
corrected before commissioning.
5.2. Pre-charge pressure
The pre-charge pressure is determined depending on the accumulator application and the operating conditions
on site. The volumetric efficiency and accumulated energy density depend significantly on it. When determining
the gas preload, the following proportional shall be applied:
P ≤ 0.9·P and P
0,max 1 0, min
Common values depending on the application are:
P = 0.9 · P
0 1
P = 0.6～0.75 · P for pulsation dampener
0 m
P = 0.6～0.9 · P for shock absorber
0 m
with P = pre-charge pressure, P
0
pressure.
The pre-charge pressure changes with the gas temperature. The pre-charge pressure P0 indicated
on the nameplate, on drawings or in other documents applies to nitrogen with a gas temperature of
20°C. After filling or draining nitrogen, the actual pressure can only be correctly adjusted to its
specified value after a sufficient temperature compensation period.
≥ 0.25·P
2
for general accumulator applications
= min. working pressure, P
1
= max. working pressure, P
2
= mean pulsating
m
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