7
Parker Olaer
Accumulator and Cooler Division
Sandycroft, UK
Product Information
Accumulators
Catalogue HY10-4005-UM/UK
precharged with nitrogen.
2. Check details of accumulator on label and shell for maximum working pressure. The maximum
hydraulic system pressure must not exceed the MWP of the accumulator.
3. Always use a nitrogen pressure regulator valve when the accumulator shell pressure rating is
lower than gas pressure in nitrogen cylinder.
4. Precharge pressures vary with operating conditions. CONSULT PARKER OLAER if no precharge
has been previously recommended. For a guide the following values can be used; - Storage
application: 90% of minimum allowable system pressure, Shock application: 90% of flow
pressure at accumulator position, Pulsation application: 70% of mean pumping pressure, NB.
Allowing precharge to fall below 20% of maximum system pressure in a bladder accumulator
may cause
premature failure of the bladder
. Excessive precharge pressures in relation to
minimum system pressure may cause failures of the bladder and/or poppet valve and in piston
accumulators, may cause excessive stresses due to the piston frequently contacting the end
cap.
5. Ensure that moving parts such as bladders and pistons are adequately lubricated with
system fluid before commencing precharging. This is especially important where the
system fluid is of low viscosity e.g. water based.
CONSULT PARKER OLAER FOR FURTHER INFORMATION.
PRECHARGING PROCEDURE
The following procedures should be adopted for safe precharging of accumulators.
For accumulators having a working pressure less than the nitrogen source refer to fig.2.
For accumulators having a working pressure equal to or greater than the nitrogen source refer to fig.3.
see note 4.
For accumulators fitted with a permanent charging set refer to fig.4.
For transfer barrier accumulators fitted with a back-up-bottle or remote charging point, refer to fig.5.
Procedure 1. – using a Nitrogen Pressure Regulator Valve (NPRV) fig.2.
•
Remove protective cap (1) if fitted and sealing cap (2).
•
Attach NPRV (3) to nitrogen cylinder (4). Ensure centre spindle (10) is fully unwound.
•
Attach charging set (5) to accumulator gas valve assembly (6) and connect charging hose (7)
between NPRV (3) and charging set connection.
•
Back off handle (8) anti-clockwise until loose, check gas bleed valve (9) on charging set is closed
and screw handwheel (10) clockwise to open gas valve.
Do not screw knob down tight.
•
Open nitrogen cylinder valve by turning key (11), cylinder pressure will register on right-hand
gauge (12). This pressure should be checked against the required precharge pressure.
•
Turn handle (8) clockwise until outlet pressure on left-hand gauge (13) registers 10% higher than
required precharge pressure. When pressure on the charging set and outlet gauges are equal,
close nitrogen cylinder valve.