Hamilton Jet HJ241, Manual

Page: 128 / 202

9.24
9 OVERHAUL
9.7 T
AILPIPE
A
REA
- O
VERHAUL
HJ-241 / HSRX
9.7.5 Impeller Area - Overhaul
Minor corrosion damage around the Wear Ring /
Impeller position inside the Tailpipe, such as pitting
may be repaired by welding. Grind the welded
surface flush with the original surface.
If the surface wear is more than 1mm deep, a new
Intake should be fitted.
9.7.6 Impeller Overhaul
NOTE: All welds must be passivated to prevent
corrosion.
Impellers are stainless steel type CF8M conforming
to ASTM A 743 or 316 to BS 3100. Filler metal
should have chemical analysis similar to AISI 316L
(Carbon content less than 0.03%) Post weld heat
treatment is not required. Passivation is required
after welding is completed.
INSPECTION:
1. Inspect all surfaces of the Impeller for any sign of
corrosion or erosion damage. Damaged areas
should be weld repaired and dressed back to a
smooth surface.
2. Check the Impeller leading and trailing edges for
damage. In particular the outer corners of a blade
may be bent if the Impeller has been dropped or
mishandled. Bent or dented blades may be
straightened using suitable tools. Bring the blade
back to it's original smooth profile checking
against undamaged blades.
3. Inspect the leading edges, excessively worn or
blunt leading edges may be built up by welding.
Blunt Impellers cause loss of performance and
sometimes cavitation.
4. Check the Impeller O.D .
BLADE LEADING EDGE REPAIR PROCEDURE:
Drawing
HJ-241-03-001 Impellers shows the
desired blade profile. The following information
should also be referred to:
1. Dress the edge back to a smooth curve removing
the minimum amount of metal.
2. Weld repair damaged edges if required.
3. Dress both faces of the blade taking slightly more
metal off the rear side until the leading edge is the
same thickness all along.
Refer to Drawings
82206 Impeller Blade Dressing Instructions and
Balancng Information Sht 1 - 4.
4. Blend well back into the original blade surface.
5. Both front and rear surfaces are to be a smooth
uniform curve with no sudden bumps or change
in direction.
6. Grind or file a smooth radius along the leading
edge. Refer to Drawings 82206 Impeller Blade
Dressing Instructions and Balancng Information
Sht 1 - 4.
IMPELLER OUTSIDE DIAMETER (O.D.) REPAIR
PROCEDURE:
1. If the Impeller OD is excessively worn it may be
built up by welding. After welding turn the
Impeller on a mandrel to the correct OD. Use
light cuts to avoid blade distortion. Dress the
faces back flush with the original surfaces.
2. Turn the outside diameter to 239.55 - 239.40 mm
(9.431" - 9.425")
making sure that it is
concentric with the bore. (Light cuts should be
taken when turning outside diameter to avoid
deformation of the Impeller Blades).
3. File and polish the Impeller Blades.
Figure 33: Wear Ring Aft Position
C
AUTION
Avoid using excessive heat during
welding.
AFT
0.8mm(
1
32
") GAP
INTAKE
INSULATOR
WEAR RING