SPP Pumps Auto Prime Medium Head Open Set - AC & AL Range - Manual (Page 11)

Operators Handbook for
Diesel Driven Pump Sets
Manual No/Rev
W72-002E / 11
Our policy is one of continuous improvement and we reserve the right to alter specifications at any time
Page 11 of 16
PUMP VACUUM PRESSURE SEAL
The seal is product lubricated and therefore
requires only regular inspections of condition,
signified by rate of leakage, and eventual
replacement. To replace the packing:-
7.5.1 Close coupled AC50, AC75, AC80 &
AC100 pumps
1. Ensure the volute is drained and
contains no harmful residues. A drain
tap is located on the bottom of the
volute.
2. Disconnect the vacuum pump suction
line from the top of the priming tank
assembly. On AC80 and AC100 units
disconnect the back priming line.
3. Remove the complete priming tank and
sump assembly from the volute. Note
the number of gaskets fitted between the
sump
and volute. Examine their
condition and either replace or retain for
reuse
Figure 0-3 Removing impeller (AC50 shown)
4. Unscrew the impeller (LH thread for
AC50 & AC75; RH thread for AC80 &
AC100). See Figure 7-3. Note that this
figure shows a AC50 unit. On an AC80
or AC100 unit the impeller would be
tapped in the opposite direction of
rotation. Record the number of shims
fitted behind the impeller and retain for
re use. Removal of the impeller exposes
the vacuum pressure seal.
5. Remove old packing from packing
holder. Clean the holder. Examine the
spring for signs of corrosion. Replace if
necessary.
6. Cut a length of packing (see Technical
Data section for dimensions) ensuring
the ends are square. The packing
material is graphite impregnated
braided P.T.F.E.
7. Place the packing into the holder
(see Figure 7-4), butting the two
ends first then pressing the
remainder of the packing into the
holder (NB the length of the
packing is greater than the
circumference of the holder and
some difficulty may therefore be
experienced. The packing will
protrude slightly from the face of
the holder on completion.
Figure 0-4 Replacing vacuum pressure
seal packing
1. Refit the impeller ensuring that it
secures the shims and spacer
sleeve.
2. Refit the complete priming tank
assembly complete with gaskets.
7.5.2 Open coupled pumps
1. Ensure the volute is drained and
contains no harmful residues. A
drain tap in the bottom of the
volute is provided for this purpose.
2. Remove guard from around pump
shaft.
3. Release screws holding the spring
carrier to the rear cover plate and
slide the spring carrier back along
the pump shaft.
Note these are the protruding hexagon
headed screws NOT the
countersunk recessed Alan
screws which should not be
touched. This will automatically
withdraw the packing holder.
4. Follow steps 5, 6 and 7 in section
7.5.1. above.