SWDM240B OPERATION & MAINTENANCE MANUAL
3. The use time is too long, the value of parts required to be changed, is almost 80% of the new
manufacturing ones.
Repairable Criteria:
Each section of Kelly can be repaired at one or two positions at most to ensure the use. The
repair cost is less than the sale value after remanufacturing.
Methods of Repair Technology
Square-head repair:
1.Connect 1.5m steel pipe at square head for gas cutting, cut spline at surplus place for
180mm-250mm to make every it form 45 bevel edge, mutually staggered, not damaging the
steel pipe, polish that after gas-cutting.
2. Determine whether the square head can be used repeatedly, if OK, gouge square head and
steel pipe welding groove, and polish to shine.
3. Cover the square head on the spring seat to connect 1.5m new steel pipe, open grooves on
two end of new pipe to guarantee the same axial less than 1.5mm, do that according to the heat
preservation requirements for preheating and welding.
4. Install spring-stiffened arc plate and do that according to the heat preservation requirements
for preheating and welding.
5. Measure the length of key bar which required to be arranged, weld that completely,
remembering that welding should be done one step by one step. After welding, polish the
groove to avoid interference.
Positioning ring repair:
1. Do gas-cutting for the positioning ring, and remove the damaged part without breaking the
steel pipe and polish it to shine.
2. If it’s a structure of two positioning rings, do ring gas-cutting on the steel pipe between two
rings, and then install the new positioning ring.
3. Mount the new part, don’t weld the O-ring, which is a movable part, weld the kidney slot of
the positioning ring together with the other side.
4. If the steel pipe has been cut with gas, it should be weld together again for the same axial less
than 1.5mm.
Repair for the crack of Kelly center pressurized block or inclined plate:
1. Find the crack position to determine whether the steel pipe body is damaged.
2. If the crack doesn’t damage the pipe body, change or weld on the spline or pressurized block
directly.
3. If the crack damage the pipe body but the distance is not over than 1/5 circle, the operation
should be done skillful professional personnel. Figure out the crack source on two ends,
eliminate the crack source completely, repair the crack into a V-shaped groove, and then weld it
again and polish the surface.
4. The middle part of steel pipe and accessories should be changed if the crack is too long, cut
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