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VM 623.0004 GB/07.00 – Ident–Nr. 550 298
3.3 Preservation and storage of the screw pumps
3.3.1 Preservation
In the case of storage or prolonged standstill, the
pumps must be protected against corrosion. In those
cases, an outside and inside preservation is to be
provided. The durability of the protection against
corrosion, which is limited in time, depends on the
composition of the preservative to be applied and the
storage conditions.
Under normal circumstances the pumps
have no special preservative.
At an additional charge we can, however, supply
pumps and replacement parts ex factory with a preser-
vative adequate to the planned storage period.
We will be pleased to specify suitable preservatives for
you on request.
3.3.1.1 Outside preservation
The outside preservative should be applied by painting
or spraying with a spray gun.
Points of preservation:
All bright and unvarnished parts (e.g. shaft ends, cou-
plings, flange facings, valve and manometer connec-
tions).
3.3.1.2 Inside preservation
The preservative is to be applied by filling the pump. For
these purposes, the suction side of the pump must first
be closed with a dummy flange. During filling, the
pressure flange must be on a higher level than the
suction flange. During the filling process, the shaft must
be slowly cranked against the direction of rotation.
Filling must be continued until the preservative reaches
the sealing strip of the delivery flange, bubble–free.
Then the outlet side is to be closed with a dummy
flange.
Note: Not required for pumps made of stainless ma-
terials.
Points of preservation:
All bright parts inside the pump (e.g. pump casing in-
side, screw spindles, ball bearings, pressure–relief
valves).
3.3.1.3 Monitoring of preservation
In the event of prolonged storage, the preservation of
the pump must be checked by the customer at regular
intervals.
Every six months the pump level must be checked; if
necessary, preservative must be topped up to the
sealing strip on the pressure flange.
At the same time, the packing must be checked for
destruction, and repaired if necessary.
Note: Liability for damages caused by improper
preservation cannot be assumed by us.
3.3.1.4 Depreservation
Prior to setting the pump in motion, the preservative
applied must be removed.
Environmentally compatible disposal must be
ensured.
The preservative applied for inside preservation can
normally be removed by flushing the pump with the fluid
to be conveyed.
Alternative, suitable solvents may be applied for
removing the inside and outside preservation.
Appropriate solvents are for example: petroleum,
benzene, Diesel fuel, spirit, alkalis (industrial cleaners)
or any other wax solvents. Steam jet cleaning devices
with appropriate admixtures can also be used (allow
wax solvent to act beforehand).
Prior to start–up after prolonged storage,
all elastomers (O–rings, shaft seals) must
be checked for their elasticity of shape. Embrittled
elastomers must be exchanged. Elastomers of
ethylene–propylene rubber (EPDM) must always be
replaced. The pump must be filled with fluid to prevent
seizing of the components. A pressure–relief valve
attached or fitted in the pipeline must be checked for
passage.
Note: If on the plant side, the pipelines, (oil) tanks or
other parts are wetted with paraffin–containing
preservative, the entire plant must be depreserved as
paraffin is detrimental to the air separating capability of
oil. This may result in unsteady operation of the pump
and loud noise.
3.3.2 Storage
During storage of the pump, the suction and outlet
branches and all other supply and discharge branches
must always be closed with dummy flanges or dummy
plugs.
Storage should be in a dry, dust–free room. During
storage, the pump should be cranked at least once a
month. During this process, parts such as the shaft and
bearings should change their position.
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