Rollers / Stations
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Item#03
Return rollers with rings
The straight tracking of the belt may be compromised by the type of conveyed material, especially when this material is sticky and thereby adheres easily to the belt surface.
In this case, material is also deposited on the return rollers that support the belt, adding an irregular addition of scale to the roller itself.
As a consequence, not only wear and tear of the belt occurs, but forces are brought into play to move the belt away from its correct track.
Return rollers with spaced rubber rings contribute largely to eliminating the build up of scale that forms in certain conditions on the belt surface. The rings are pointed, assembled at intervals, in the central part of the roller, where they have the scope to break up the scale which normally is present at the belt centre; meanwhile flat rings mounted in groups at the extremities of the belt, support and protect the belt edges, also in cases of limited belt wandering.
Return rollers with rings should not be used as belt tensioning devices.
 Click to download NG product range |
Arrangement “NG” Return rollers with pointed rings spaced in the central part and positioned in sets at the side. Used on belt conveyors of medium capacity. |
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 Click to download NL product range |
Arrangement “NL” |
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 Click to download NC product range |
Arrangement “NC” |
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Arrangement with special flat rubber ring type B for pulp and paper and other industries. |
Download “BULK ROLLER SELECTION FORM”
RETURN - Roller selection
If you have already decided
• roller dimensions as A, B, C lengths
• shell and shaft diameter
• bearings size
• slots
• eventual rubber rings or special coatings
• and the load capacity
the roller selection can be done by simply looking into our catalogue pages and finding the correct roller to suit the requested data.
In the case that only the conveyor data is known, but the roller size is not decided, the roller selection type (series, steel, plastic, coated) and dimensions (shell and shaft diameter, bearing size, eventual rubber rings) depends on the following application data. This data must be given by the conveyor designer (for new projects) or by the end user or maintenance contractor (for spare parts):
• Belt width [mm]
• Conveyor capacity [t/h)]
• Belt Speed [m/s]
• Belt weight per meter [kg/m]
• Roller diameter (if stated) [mm]
• Idler sets distance (stations pitch) [mm]
• Angle of the side rollers (20°, 30°, 35°, 45° or other)
• N° theoretical bearing lifetime hours L10h requested (10.000, 30.000, 50.000 or other)
• Material lump size (max material block dimension) [mm]
• Transported material type, condition (dry, wet, sticky), abrasion, corrosion
• Climate, max & min temperature, marine or chemical corrosive environment.
For return rollers selection in addition to the above data :
- Are they a single flat return roller or V-return rollers?
- Are rubber rings required on the tube?
- What would be the: base roller diameter/rubber ring diameter (if stated)
- Their configuration (NG, NL, NC etc. see catalogue pages).
For impact rollers calculation selection:
- Drop height of material [mm]
- Max material lump size[mm]
- Type of loading (free fall on the belt, hopper, loading inclined plane, extractor conveyor).
According to this data and a proper load capacity and lifetime calculation (see our technical chapter), the rollers can be selected and dimensioned.
For help and guidelines with regard to roller loading capacity we refer to our roller catalogue (direct download our catalogue from this web site or request it from your local Rulmeca offices.)
In case you are not familiar with this selection and calculations, please fill accurately the attached "Bulk roller selection form" with all the requested data and send it to your local Rulmeca office.
Download “BULK ROLLER SELECTION FORM”
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