One of the greatest concerns of a packerhead pipe producer is bell quality. Most of the problems encountered can be avoided by following proper bell-making techniques. The following list of problems and possible causes, while not complete, should give you a good starting point towards solving your bell area concerns.
Overpack in Bell (showing cage lift)
Check these first when bell issues develop:
- Make sure that the bell down unit is lifting the curing pallet to the proper height.
- Check that the top of the longbottom is 1/4″ (6 mm) above the pallet when the bell down unit is raised.
- Check the timer for proper vibrating and turning time.
- Make certain that the proper amount of water is sprayed onto the concrete during the bell cycle, if applicable.
- Check that the pallets have been properly cleaned and oiled.
- Check to see that the shock absorber pads have a minimum of 1/8″ (3 mm) clearance (applies only to older machines).
CONCERN: Cage Lift
Too much concrete on the rollerhead while making bell.
SUGGESTION: Check to see if it is over-packed.
CONCERN: Cracks in Top of Bell
Bell down unit is lifting pallet too high.
Pallet is not properly seated in mold for turning and vibration.
Improper stripping of mold.
Pipe sticking to mold.
SUGGESTION: Check to see if the mold is level.
Check to see if the material is too wet.
CONCERN: Exposed Wire or Wire Shadow in Bells
Cages are going off center.
Cages are out-of-round.
Cage diameter is incorrect.
Bells were not properly expanded.
SUGGESTION: Try using cage stirrups.
Bells should be expanded to center on pallet flange.
CONCERN: Rocky Exterior Bells
Bell material too dry.
Not enough bell water added.
Not enough material in bell.
Over or under vibration during bell cycle.
Vibrator weights incorrectly set.
Adjustment to shock absorber pads incorrect.
Bell down unit not lifting pallet.
The top of the longbottom should be 1/4″ (6 mm) above the top of the pallet when the bell down unit is raised.
Check mix design.
Check bell reinforcing for size and location.
SUGGESTION: Add concrete until cage stops turning.
Check mix design, you may have too much rock.
CONCERN: Rough Interior Bells
Bell material too dry.
Not enough bell water added.
Not enough material in bell.
Over or under vibration during bell cycle.
Vibrator weights incorrectly set.
Adjustment to shock absorber pads incorrect.
Bell down unit not lifting pallet.
The top of the longbottom should be 1/4″ (6 mm) above the top of the pallet when the bell down unit is raised.
Dirty pallets.
No release agent being used.
Release agent not properly applied.
Wrong type of release agent used.
Check mix design.
SUGGESTIONS: Add concrete until cage stops turning.
Check mix design, you may have too much rock.
ISSUE: Picking Off of the Bells on the Transition
Concrete is too wet.
Cage lift.
Over or under vibration during bell cycle.
Vibrator weights incorrectly set.
Adjustment to shock absorber pads incorrect.
Bell down unit not lifting pallet.
The top of the longbottom should be 1/4″ (6 mm) above the top of the pallet when the bell down unit is raised.
SUGGESTION: Use an admix to reduce concrete bond to mold.
ISSUE: Swedging
Concrete is too wet.
Too much concrete on the rollerhead during the first pass while making the bell.
Too much concrete on the rollerhead during the second pass.
Cage lift.
SUGGESTIONS: Check to see if it is over-packed.
Pipe settles after stripping.
If you have any questions, please contact our customer service team by phone +1.989.354.1000.
