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1. Polysius Services 2. Grinding of supporting rollers, kiln tyres and thrust rollers 3. Grinding of supporting rollers in progress 4. Measuring device to check the diameter and out of roundness of tyres and supporting rollers 5. Dimensional stability after refurbishment 6. Damages due to miss alignment 7. Refurbishment of Mill slide rings

Senior Service Engineer Udo Feldotto

Polysius Anlagenservice

Refurbishment of kiln tyres and

supporting rollers by grinding units

surface damages of kiln tyres and or supporting rollers

Reason for geometrical errors and surface damages:

- Process difficulties (kiln bending due refractory failures, not uniform coating)

- Increased surface wear, due to malfunctioning of axial kiln movement

- Misalignment (Skewing, Inclination failures)

Abnormal contour of kiln tyres and supporting rollers:

- Surface damages, scoring and scuffing in circumference direction und corrugation

across

- Surface deformations

Grinding service by Polysius: The following grinding units are available

Big grinding unit (Quantity 1)

Operational field: Rotary Kiln : Tyre diameter Ø > 5m, Tyre width max.1500 mm

: Roller diameter Ø max 3m, Roller width max.1500 mm

Smaller grinding unit (Quantity 2)

Operational field: Rotary Kiln : Tyre diameter Ø < 5 m, Tyre width < 900 mm

: Roller diameter Ø < 2 m, Roller width < 900 mm Mill Slide ring : Slide ring diameter max 10 m, Slide ring width < 900 mm Trunnion shaft : Trunnion shaft Ø max 3 m

Rotary drums : Tyre diameter Ø < 5 m, Tyre width < 900 mm

: Roller diameter Ø < 2 m, Roller width < 900 mm

Cup wheel grinder unit (Quantity 2x2)

Operational field: Rotary Kiln: Lateral tyre surface

: Thrust rollers (Fixed and or Hydraulic thrust units)

Kiln supporting roller:

Corrugation due to kiln drive vibrations

Kiln tyre:

Convex shape of kiln tyre

Tyre and roller surface damages in circumference direction

Example: The inclination of the supporting rollers differed by 0.5% Due to the inclination failure the customer skewed the supporting rollers wrong Finally the skewing failure create the surface damage.

Grinding of supporting rollers, kiln tyres and thrust roller

Grinding of supporting rollers, kiln tyres and

thrust roller

Polysius is providing the full service for

refurbishment of damaged surfaces, including

necessary adjustment

Grinding of supporting rollers in progress

Measuring device to check the diameter and out of roundness of tyres and supporting rollers

Dimensional stability after refurbishment:

- Supporting rollers Out of roundness max 0,20 mm (Rotary Kiln, Rotary drum)

Measuring device to check the diameter and out of roundness of tyres and supporting rollers

Alignment of thrust rollers to theoretical Kiln axis

Thrust roller:

Possibilities of miss alignment

Thrust roller:

Alignment of thrust rollers to theoretical Kiln axis

Different inclination between thrust roller and kiln axis

Angle miss alignment due to settlements, or wrong assembly

= =

Thrust roller:

- Offset to the vertical centre line

- Due to our experience offsets

bigger than 5 mm will cause surface

damages

- Realignment by using circle

measuring device

= =

B B

Thrust roller offset in

accordance to theoretical

kiln centre line

A : Kiln rotation direction

B : Allowable lateral offset =

2.0 to 5.0 mm

The lateral offset must be

selected that the

tyre slightly presses the

thrust roller downward!

Damages due to miss alignment

Damages due to miss alignment

Grinding of tyre lateral surface and thrust roller

Grinding of tyre thrust surface and thrust

Roller in progress

Important slide ring surface areas

1 Contact area of slide shoe bearings

2 Contact area of the housing seals

Damaged slide ring surfaces have to be refurbished for a trouble free mill operation

Polysius is providing a full service of slide ring surface refurbishment

Refurbishment with powerful belt grinding machines

Different grinding belts are available (from rough up to fine quality)

Measuring device to check the diameter and out of roundness of slide rings

The grinding works have to be done with the mill auxiliary drive

The maximum mill speed is 1,5 rpm

Polysius provides mill turning device, if required

Measuring device to check the diameter and out of roundness of the slide ring

Measuring device to check the diameter and out of roundness of the slide ring

Refurbishment with powerful belt grinding machine

Slide ring surface

before grinding /after grinding

• Executed biggest radius reduction

of seal area up to 12 mm

carried out in 2003

• Reduction of slide ring diameter

< 2 mm will not effect the

contact between slide ring and

bearing shoes