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12838 Stainless Drive, Holland, MI 49424
MECHANICAL SEAL
MAINTENANCE
Although mechanical seals, when properly installed,
require minimal maintenance, periodic inspection should
be performed to help identify and avert a potential failure.
The following procedures are recommended:
1. Establish a daily routine of inspecting all equipment.
2. For lubricated seals, check for adequate seal
lubricant in reservoir.
3. For double mechanical seals, check seal chamber
pressure source (nitrogen bottle, etc.) for proper
pressure (20 PSIG above tank pressure) and for
adequate supply.
4. Observe mixer shaft when operating for excessive
deflection. Shaft deflection (or run-out) at the top of
the seal must not exceed .075" T.I.R. maximum.
Run-outs exceeding this limit are an indication of
mechanical or process problems (bent shaft, high
inlet flow impinging directly on impeller, etc.) and not
only will destroy the mechanical seal, but may
damage other components of the mixer and tank.
5. Observe for signs of leakage around seal. Excessive
leakage is an indication of seal face wear, improper
installation, excessive shaft deflection, etc. If the seal
has provided a relatively long service life, wear is
probably the cause and indicates that repair or
replacement of the seal is in order.
6. When mixer is not operating, check seal drive collar
set screws, stationary insert retainer cap screws and
mixer shaft coupling hardware for proper tightness.
Also check for excessive clearances in the mixer
shaft support bearings. This can be detrimental, not
only to the mechanical seal, but also to the mixer
final drive gearing.
Copyright 2018 BRAWN Mixer
SEAL INSTALLATION
MECHANICAL SEAL REPAIR
Mechanical seals are precision-manufactured, and
effective sealing is dependent upon maintaining this
precision. Therefore, if the proper equipment for repair
of the seal is not available, it is recommended the seal
be returned to the factory for repair.
The following points apply to virtually all mechanical
seals:
1. Read and follow the seal manufacturer's instructions.
2. Cleanliness of all seal components, especially the
mating faces of seal ring and stationary insert, is of
utmost importance.
3. Check the rotating seal components for excessive
wear and to be certain the drive pins and springs are
free in the pin holes or slots. Replace all worn or
damaged components.
4. Install new set screws and make sure they are free
in their threads to turn and seat properly.
5. Install new O-rings and shaft packing.
6. Seal rings and stationary inserts are delicate and
require special handling. Careless handling of these
components can result in irreparable damage such
as fracture, chipping, scratches, etc.
7. Sealing faces are lapped surfaces and must be flat
to within three (3) light bands for effective sealing. If
lapping and inspection equipment is not available,
return seal assembly to the factory for repair. A used
seal face should not be mated with a new face.
8. Before re-installation of the seal, check the mixer
shaft support bearings for excessive axial clearance
(.005" maximum) and radial clearance (.001
maximum). Also check the output shaft face for
excessive run-out (.003" maximum). Correct any
deficiencies.
9. Visually inspect the mixer shaft for damage as
indicated by nicks, scratches, dents, wear, etc. Shaft
surface finish must be 32 RMS or better. Also
inspect seal flange mounting surface for damage.
Correct any deficiencies.
www.BRAWNMIXER.com
2/5/2018
& M
AINTENANCE
Phone: 616/399-5600 Fax 616/399-3084
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