ANALYSIS OF ECONOMIC AND OTHER EFFECTS IN APPLYING TECHNOLOGICAL COATING OF THE DRUMS ON THE RUBBER CONVEYOR BELTS SYSTEMS USING THE METHOD OF “SEGMENTATION”

Conveyor systems based on rubber conveyor belts, massively used in mines and surface Cups to transport tailings, coal, ores, various non-metals and other raw materials.

The basis of each system based on rubber conveyor belts consist of the following elements:

  • The supporting metal structure of the transport system
  • driver of the transport system consisting of engines, gearboxes and other components
  • rubber conveyor belts of various qualities, sizes and shapes depending on the type of raw material being transported
  • reel (operating and tightening development), which are coated with rubber for resistance to wasting
  • system-rollers with rubber rings or “SGC” Return rolls The subject of this analysis is the evaluation of the economic effects (savings),
    which is achieved by coating on drum rubber conveyor system with rubber bands, using the method of “segmentation”.

1. EXISTING TECHNOLOGY OF DRUM COATING

In current practice, on transportation systems, are used mainly in the form of a rubber compresses mantle, which in an autoclave applied to the circumference of the drum. The technological process of coating drum rubber is processed through the following stages:

  • removal of the drum and its preparation for coating (removal of worn old rubber linings, finishing the damaged surface of the drum, remove residual deposits of transported materials, sanding the outer surface of the drum on which the fit-wrap, etc.)
  • transport the drum to the rubber factory where preparations were being made for the drum coating (coating the outer surface of adhesive agents and adhesives)
  • preparation rubber lining (preparing raw rubber mixture and overheating on roll mill, extracting the required thickness and cutting to size according to the technological requirements of gumming by autoclaving and surface coating adhesive hot vulcanizing)
  • Silk wet bandage strip and inserting into the autoclave, together with wheelchair on which the drum is placed
  • vulcanization by autoclaving at a prescribed temperature on technology of approximately 145 to 155 degrees Celsius
  • extraction of drum autoclave, processing edges, burn relief diamond dimensions given – transport and installation of the drum to the rubber conveyor system

2. NEW TECHNOLOGY PROCESS ON COATING DRUMS

The new technological process of coating rubber drums for transport systems with rubber bands, significantly different from the current one. Instead of a complete rubber sheath on your load-bearing surface of the drum, put the separate segments are composed of steel and rubber layers. Unlike existing technological process in which the deterioration of the to rubber lining necessary to make disassembly and replacement of the entire mantle, new technological process enables perform on-site replacement of old with new segments, without large and lengthy interruption of work processes.

The segments are themselves made separately, in the following manner:

  • acquisition stone foundations segment thickness of 4 mm, a certain width, length and radius of the fittin on the drum (depending on the size of the drum)
  • sandblasting metal surfaces basics segment that will be covered with rubber
  • degreasing metal area of sandblasted basics segments
  • preparation of raw rubber compound and overheating on roll mill, and then pull the required thickness, cutting to size moulds for vulcanization
  • preparing moulds for vulcanization and mount the appropriate equipment
  • filling the mould for vulcanization, vulcanization, extracting moulded parts by prescribed technology and repeat the procedure until you get the required number of segments

Finished segments are fitted on the drums in two ways: through direct metal welding the segments on the mantle of the drum and the other way is much more convenient to use for the installation of special segments of the “T” rails. These mounts are welded along the length of of the drum (through special grooves at several places along the length of extracted router). The number of “T” of the carrier is determined according to the number of segments required and which in turn depends on the characteristics of the drum. To ensure easy installation segments in the grooves of “T” bracket on the mantle of the drum, tin bases of the segments are wider than the rubber lining.

Segments of the coating drum can be from any part or for the whole length of the drum, or from two or three parts and the size of the drum depends on the characteristics of the technological process and in operation of the drum within the of the transport system.

3. EFFECTS ACHIEVED IN THE NEW SYSTEM OF DRUM DISPOSING

a) Measurable effects

The measurable effects achieved in the implementation of new technological procedure drums with rubber coating method “segmentation” are related to the possibility of calculating the direct savings on all drums that are in the system of conveyor belts (driver, inflection and tightening drums). This takes into account the amount of rubber components and sheet in a segment that is spent lining and drum life of the rubber segments compared to the existing method of complete coating drum. An overview of these effects is given in the following table.

b) Immeasurable effects:

The immeasurable effects that can be expected in the application of new technologies coating drums method “segmentation” are:

  • procedure for replacing the drums with the existing technological process is expensive and complicated repair job, which leads to prolonged interruption in the operation of the transport system
  • unlike the existing technological process by which the drum has to be removed and taken to prepare and re-coating with the new process technology segments which are installed (replaced) on the spot without removing the drums
  • In this process there are no long delays, which is very important for the efficiency of the transport system
  • because the replacement is performed on the spot transport costs are avoided from hiring, machinery for loading and unloading of drums
  • there is no need for prior written technical operations on the preparation of drums such as sandblasting, coating drums for re-coating with rubber sheathed
  • a significant savings in labour, whose engagement with new technological procedure when replacing segments minimized compared to the existing method that requires substantially greater involvement of the labour force on disassembly, preparation, loading, transport, unloading and re-assembly of drums to transport system

In Srbobran, February 2011.

Preparation: Kovacic Nikola,
akademic Krunic Tomislav, dipl. oec.