Seating The Packing; Replacing The Packing - Brawn BGMF33 Operation And Maintenance Manual

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SEATING THE PACKING

What makes a stuffing box seal effectively is a thin film
of lubricant between the shaft and the packing. If this
film is too thick, it will not be able to resist the tank
pressure and, therefore, will not seal. If the film is too
thin, it will dissipate, resulting in excessive heat that will
cause deterioration of the packing and damage to the
shaft. The film thickness depends on how tight the
packing is compressed. To obtain the correct
compression, the packing should be run-in as outlined
below, using heat and pressure to ensure that the
packing molds itself to the cavity between the shaft and
the stuffing box hub.
1. Tighten the two packing adjusting nuts, located
above the packing gland, until they feel snug.
2. Loosen the adjusting nuts and re-tighten until they
are only finger-tight.
3. Start the mixer and gradually tighten the adjusting
nuts in quarter-turn increments, until the outside of
the box is too hot to keep your hand on it
(approximately 125º F). Allow about ten minutes
between adjustments for the temperature to
stabilize.
4. Turn the mixer off and tighten the adjusting nuts
evenly while the packing is still hot.
5. After the stuffing box has returned to room
temperature, loosen the adjusting nuts and re-tighten
until they are only finger-tight. Check to make sure
that the packing gland is parallel with the top of the
stuffing box to ensure uniform compression.
6. To maintain the correct lubricant film thickness, the
packing must be periodically tightened. The intervals
between adjustments vary, depending on your
specific operating conditions. Initially, we
recommend that the stuffing box be checked daily for
leakage or excessive temperature. After monitoring
for a few days, you will be able to determine a
maintenance schedule that is practical for your
application. When making adjustments, do not
tighten more than a quarter-turn, to avoid excessive
friction.
Copyright 2015 BRAWN Mixer, Inc.
BGMFSB-S
ERIES
www.BRAWNMIXER.com
O & M
PERATION
Phone: 616/399-5600 Fax 616/399-3084
REPLACING PACKING
1. Make sure that the mixer is turned off and the tank is
vented to atmospheric pressure.
2. Remove the OSHA-compliant cover guards from the
mixer pedestal.
3. Remove the adjusting nuts, split packing gland,
packing, and lantern ring (if applicable) from the
stuffing box.
4. Clean the shaft and stuffing box hub and inspect the
shaft for damage. If the shaft is significantly worn, it
should be repaired or replaced.
5. Select the correct size and type of packing (refer to
the mixer specification sheet). Using a bar that is
the same diameter as the mixer shaft, wrap the
packing around the bar once for each ring of packing
that is required. We do not recommend cutting the
packing on the mixer shaft because it can score the
shaft and cause leakage. If butt-cut joints are
desired, make one longitudinal cut across all rings
(see Figure 4). If diagonally-cut joints are desired,
draw two longitudinal lines, spaced equal to the
packing thickness. Then, individually cut each ring
at a 45-degree angle (see Figure 5).
6. Coat all surfaces of the packing rings and lantern
ring (if applicable) with a high-quality lubricant that is
compatible with the product and suitable for the
service conditions, and install in the sequence shown
in Figure 1 or Figure 2.
7. After each ring of packing is installed, it should be
tamped in place. A half-round piece of tubing or pipe
makes an excellent tamping tool.
8. For optimum sealing, each ring of packing should be
installed with the split line oriented approximately 90
degrees relative to the ring preceding it.
9. After all packing has been installed, assemble the
split packing gland and adjusting nuts. Then,
lubricate and seat the packing as explained in
Sections on LUBRCATION and SEATING THE
PACKING.
8/6/2015
M
AINTENANCE ANUAL
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