Flowserve Mechanical Seal and Seal Support System Storage - Manual (Page 2)

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If a mechanical seal is stored installed in a centrifugal pump, the preparation and storage conditions
for both components must be considered together. In many cases, the centrifugal pumps are perfor-
mance tested or hydrostatic tested on water prior to storage. The pump and seals must be dried before
storage. This will require completely draining the pump, seal, and seal support system. Blowing dry air
or nitrogen through the seal chamber and seal support system can aid in drying out these cavities.
Some pump storage procedures require that oils or liquid phase corrosion inhibitors are used inside
the pump casing to prevent corrosion. These products can potentially damage the mechanicals seals
if they come into contact with the seal components. Vapor phase inhibitors which do not leave a film
or residue on the surfaces present less hazards to the seals. The use of desiccants or drying agents to
absorb water vapors in the pump casing is the best solution for mechanical seals.
All openings on the pump, seals, and seal support systems must be flanged or plugged to isolate
the pump casing from the environment. Blank flanges should be gasketed and threaded connections
should be plugged with a suitable plug and sealant. The clearance between the seal gland and shaft
(in the area of the drive collar) should be masked off to prevent atmospheric contamination, debris or
water from entering the seal gland.
Many pump storage procedures require that the shaft be rotated several revolutions by hand at regular
intervals. This may serve the function of lubricating the bearings, preventing brinelling in the bearings,
or minimizing shaft sag. The mechanical seals can tolerate this procedure without damage. Any masking
between the seal gland and shaft that is removed during shaft rotation must be reapplied when complete.
4 Expected Storage Life
For storage periods longer than two years, environmental conditions may influence the flatness of
rotating and stationary seal faces and cause deterioration of some gasket materials. After two years of
storage, Flowserve recommends onsite professional inspection and static testing of product assem-
blies prior to commissioning by a Flowserve representative. After three years of storage, Flowserve
recommends that mechanical seals are returned to a Flowserve facility for inspection and air testing.
Damage and contamination of internal mechanical seal components may not be readily apparent. The
condition of the packaging or pump in which the seal was stored may provide indicators of corrosion,
physical damage, water damage, or a dusty storage environment. If the mechanical seals have been
stored in conditions not meeting the recommendations above or if the storage life history is unknown,
the user should return the seals to a Flowserve facility for inspection and air testing prior to use.
Failure to confirm the integrity of improperly stored mechanical seals could lead to excess leakage and
seal damage during commissioning.
5 Air Testing of Pump Assemblies
Users should consider air testing the complete pump and seal package prior to final installation.
This procedure commonly consists of blocking in the pump, pressurizing the pump to a low pressure
(typically 1.7 bar or 25 psi), and measuring the pressure decay over a defined period of time
(typically 30 minutes). Pump assemblies which have excessive pressure decay should be examined
to determine the source of the leakage and take corrective actions. If the seal is determined to be
leaking, it is recommended that the seal be inspected by a Flowserve specialist.
In dual seals, the static air test should be repeated on the buffer/barrier/containment seal chamber to
confirm the integrity of the outboard seal. Non-contacting seals designed to run on nitrogen should be
statically tested with nitrogen.
6 Additional Information
The requirements and recommendations in this document are applicable to a wide range of mechanical
seals and products. For additional information or for a review of special storage requirements, please
contact your Flowserve representative.