BEDU S Series, Руководство по эксплуатации и техническому обслуживанию

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c) Replacing dynamic seals
To remove the dynamic part of the external seal

it is advisable to hold the spring

and,
with a rotation movement in the same direction as that of its coil, exert a traction force paral-
lel to the shaft
 D, by paying attention not to scratch this last. After greasing the shaft to
make assembly easier, insert the new mechanical seal by rotating the spring in the direction
opposite to that of the coil; use a pad interposed with a soft bearing to press the seal up to
make the spring rest on the external stop ring

fixed on the shaft.
To replace the dynamic part of the internal seal  , it is necessary to disassemble the exter-
nal ring

, secured on the shaft by means of threaded grub screws

. We recommend to
mark accurately the ring position on the shaft before disassembly, so as to ensure
the correct seal pre-load later.
Loosen the hexagonal head screws  and disassemble
the flange  (with the static part of the internal mechanical seal) and the O-ring  . To ex-
tract the dynamic part of the internal seal

it is advisable to use an iron wire bent at 90° at
one end to hook the first or the second coil of the seal spring  . Exert a traction force paral-
lel to the shaft

D, by paying attention not to scratch this last. Ensure that grub screws

did not scratch the shaft  D.
After greasing the shaft to make assembly easier, insert the new mechanical seal by rotating
the spring in the direction opposite to that of the coil; use a pad interposed with a soft bear-
ing to press the seal up to make the spring

rest on the internal ring

(or on the seeger)
fixed on the shaft.
4) Magnetic drive coupling (see Figure 4)
a) Access to inner magnet
Place a basin of suitable size and capacity under the inner magnet cover; loosen the hexag-
onal head screws

and disassemble the cover

and the O-ring

. Unscrew the screw
 , remove the washer  and disassemble the inner magnet  . On reassembly, pay atten-
tion not to pinch the sealing O-ring

housed on the centering ring

. We recommend the
use of tools in non-magnetic material.
d) Replacing bearing bushes
Proceed as described at points a) , b), c) , e) . To replace the graphite bearing bushes  , it is
necessary to break them with a chisel or other convenient tool, by paying great attention not
to damage the seat diameter of bushes and their base plane. Before inserting new bushes,
clean very carefully bush seats with alcohol in order to remove all impurities and dry well. Fit
new bushes by
spreading a layer of glue of “LOCTITE 648” type over their outer diameters,
by paying attention that the cut bush and the integer bush match perfectly. First introduce
the integer bush and then the other, by letting glue dry for about 10

15 minutes. When the
operation is over, set to zero the bush shims with the relevant housing covers. If a surfacing
feed is not available, you can choose a base plane abraded with fine emery cloth with P80
type grain for rough grinding and 400 type grain for finishing, by making a circular motion.
For assembly, follow the instructions at points
e) , c) , b), a) .
e) Replacing gears and shafts
Proceed as described at points a), b) , c) . Loosen the hexagonal head screws

which fas-
ten the rear cover

and remove this last, by keeping into account that the operation may
become difficult for the accuracy of shafts and dowel pins  . For pumps of size greater than
that of NEX400, loosen the hexagonal head screws on the front cover.
f) Safety valve replacement
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