Start  Rotary vessels  Regeneration by grinding

Regeneration of rings and rollers raceways by grinding

















INTRODUCTION

Basic components of a rotary vessel are rings and rollers, forming its support system. The vessel's primary movement is rotation, being accompanied by axial displacement. Resistance of both movements is closely dependent on the contact conditions between the surfaces of rollers and rings. Correct contact between the two is guaranteed only when the raceways of both components are cylindrical in shape. Unfortunately, even during normal operation, the rotary vessel is exposed to numerous factors, which in a long run will cause deformation of the contact surfaces, making the rolling components lose their original shape to a larger or smaller degree.
Such factors are:
  • roller shafts misalignment /1/;
  • ring axial run-out /2/;
and they result in excessive and unevenly distributed loads on the contact surfaces of the ring and the rollers.
Total elimination of the above-mentioned factors is difficult, and sometimes even impossible. Shape errors (/3/, /4/) are therefore inevitable, and their magnitude and rate of occurrence depends on the number and values of faults.
Even the smallest errors disturb the correct distribution of forces in the rotary vessel's support system, as points appear where the unit loads exceed the permissible values /5/.
In extreme cases, such errors can cause serious disturbances in the vessel's movement, both rotary and axial.
Movement resistance and incorrect distribution of forces can result in considerable damage, such as:
  • wear, breaks of the thrust stop blocks /6/;
  • bearing bushing damage by excessive loads /7/;
  • breaks of the roller shafts' thrust collars;
  • further, hastened wear of the rollers and rings raceways caused by increased unit loads in the contact areas /8/, /9/.

Such a movement resistance has also a negative effect on the drive system, where the teeth wear in the gear unit is faster /10/. This creates a feedback which results in further deformation of the rings raceways, this time as characteristic furrows /11/.
Removal of such a damage entails significant costs caused by both, production downtime and elimination of the failure results.
Periodical checks and restoration of the correct shape of rings and rollers raceways is desirable from the technical point of view and fully justified business-wise.

TRADITIONAL MACHINING

The shape can be restored in a traditional way: by dismantling and machining on stationary equipment. In such case, the downtime is inevitable: if the rollers are refurbished, the downtime will be shorter (a few dozens of hours); in case of the ring, the downtime will be fairly long (several weeks).
The costs of restoration are also sizeable, and include amongst others:
  • dismantling and re-assembly (in case of the ring, often the kiln's shell needs to be cut);
  • transport (difficult, as the parts are usually oversize);
  • machining (machine tools are few and expensive).
Machining without dismantling any parts of the facility, even during its normal operation can significantly reduce such costs.
In case of the rollers, which axis of rotation is relatively stable, the available machining operations include turning and grinding on more or less adapted traditional machine tools.
In case of raceway rings, changing position of the axis necessitates much more sophisticated and refined technology, unavailable on a day-to-day basis.
The machining requires also a deep knowledge and an extensive experience in measurements and adjusting such facilities.

NEW SOLUTION

The ZMP engineers do have such knowledge and experience.
The company has independently engineered, manufactured and successfully implemented the advanced equipment to machine the rings and rollers raceways without dismantling.
The equipment in question is a high-capacity, abrasive belt grinder with a self-adjusting positioning system (/12/).
The axial displacement of the machined piece, occurring always in the rings and sometimes in rollers, is compensated by two rotary articulated joints in the grinder's support structure, which allow the follow-up change of the equipment position (/13/).
A specially designed roller guiding system ensures the stability of the machined diameter. The solution is based on the three-point method of determining the circle diameter (/14/).

SCOPE OF THE SERVICE

With such specialized equipment and necessary engineering expertise in rotary vessels, we can offer you the comprehensive service of refurbishing the raceways of rollers and rings.
The service includes:
  • strength analysis to determine the usefulness and possibility of removing the material layer necessary to restore a correct shape;
  • measuring assistance and supervision of rollers position adjustment, which is necessary during the process;
  • raceway regeneration (/15/, /16/, /17/, /18/) with control of the generator's diameter and shape on the machined piece.

ADVANTAGES

  • no need for costly and time-consuming dismantling and re-assembly;
  • elimination of expensive transport to and from the machining facility;
  • minimizing the production losses (high capacity machining);
  • during machining, the reference line is actual axis of rotation of the piece (high accuracy, minimal shape errors);
  • small surface roughness after regeneration.


APPLICATION

  • grinding the raceways of rotary vessels' rings and rollers,
  • grinding other large rotary pieces, without dismantling.


See also: regeneration of rollers' raceways by turning.




























Stock Market ShMP (Secondhand Machines Parts)

no title of offer
offer expiry date
43 - SP   system smarowania pierścieni 2006-02-24 do odwołania
74 - SP   Sztabki smarne EasyBar 2010-05-25 do odwołania
56 - SP   Zespół napędowy walczaka 2007-10-19 do odwołania
55 - SP   Zespół rolek nośnych 2007-10-19 do odwołania
54 - SP   Pierścień biegowy 2007-10-19 do odwołania
53 - SP   Wieniec zębaty 2007-10-19 do odwołania