CONVENIENT LUBRICATION OF ROLLERS AND TIRES RACEWAYS
Selection of the right type of lubricant for the rolling elements is one of the
most important problems which face the rotary drum maintenance stuff. Oil based
lubricants or even occasional use of water generates disadvantageous effects in
the surface layers of raceway's material. On the tire - see the photo below - are
presented the effects of pitting phenomenon, depending on the chipping of the parts
of material, which is subject to changeable pressure in presence of incompressible
liquid. Micro cracks present on the tire (and/or roller) surface are filled up with
the oil (or water) and those are compressed by the very high contact pressures,
causing further defects propagation, up to the form of wide material chipping.
Besides, it is not difficult to imagine wet (and/or oiled) surface in dusty environment.
It is not too esthetic view. Moreover connection of dirt, dust and other production
process based substances, is not only disadvantageous appearance, but also a difficulties
in maintenance and in even force distribution in supporting system. Alternative
to oil and water is graphite.
This special form of carbon as a medium of lamellar, hexagonal crystal structure
and anisotropic properties, under the load of even low tangential stresses, shows
easy displacements of crystal layers. This property (called compressibility) is
the base of use of graphite as the main or as a base component of the lubricant.
Additionally, use of graphite, which is a dry lubricating medium, enhances the cleanness
of lubricated surfaces. Not without the matter are also the economical and the ecological
Besides the graphite there are other known chemical compounds of similar properties.
In common use we can find also:
- aboron nitride,
- molybdenum diselenide,
- molybdenum disulfide,
- wolfram disulfide.
Those compounds, although of similar properties, differ from each other with chosen
parameters of which the most important is the coefficient of sliding friction. Also
the graphite possesses a lot of additional features, which determines or even excludes
its use in specific conditions.
During the selection of the proper lubricating medium there should be considered:
- value of slope of the drum,
- rotary speed of the drum,
- unitary pressure in the spot of tire and roller contact,
- environment conditions (temperature, dustiness, ...),
- type of drum's drive.
Graphite lubrication system
SOLUTION DEDICATED TO INDIVIDUAL REQUIREMENTS
Knowing the object's parameters and specific exploitation conditions, we can determine
the type of lubricant - optimal for the analyzed application.
In case of graphite based solution or similar medium indication - we will also design
the right construction for product application.
To complement the implementation process, we offer manufacturing and assembly of
complete system sets on the object.
- implementation of the new raceway lubrication system changes the friction coefficient
between the tire and rollers;
- such a situation requires calculation of the new, target values of rollers' skews
to compensate changes of axial forces, which are the effect of mentioned friction
- in case of objects which are subject to our frequent audits, calculations are executed
basing on the data obtained during the last inspection;
- in case of objects of transient state of support system geometry, necessary complementation
of the service is detailed measurement of the object to determine actual skews of
the rollers and axial forces distribution;
- in both cases we provide suitable assistance - supervision over the adjustment implementation
of rollers skews, to obtain the expected final effect.
ADVANTAGES OF GRAPHITE LUBRICATION
/ Ask for
- minimization of pitting and spalling effects,
- increase of object's axial stability
(by the increase of friction coefficient stability),
- constancy of friction coefficient on the wide spectrum of temperature conditions,
- zincrease of raceways' cleanness
(limitation of risk of raceway's damages in case
of presence of unnecessary dirt on surface),
- easy and safe lubricant application,
- limited to minimum servicing activities,
- possibility to adapt the system for any type (construction) of rotary drum,
- low cost of using.