Lubrication in the cement industry presents some unique challenges. The problem is not so many types of equipment, but the environment in which the machine operates, which can vary from season to season depending on the location of the facility.
This factor should be carefully considered when choosing and applying lubricants because oils and greases that work well on almost the same equipment may not be effective in the conditions that this industry often needs to encounter.
Transportation of Raw Materials;
Typically, a cement factory is located adjacent to or very close to a quarry. The raw material should be transported from the quarry to the cement factory and eventually to large storage hoppers. The mode of transportation is usually done with conveyors, the most common types are belt conveyors.
Even if the raw material is brought to the cement plant from a distance, there will still be many conveyors throughout the plant.
These conveyors are usually driven by electric motors, some of which will be large due to the power required to pull the belts. Larger types have grease nipples that require sparse greasing. In addition, there will be greased bearings on both the drive end and the non-drive end and the tension rollers between them.
Many different types of grease are successfully used in these applications. The specific grease used is not as important as the frequency of greasing, which can help keep dust away from the bearings and prevent rapid wear rates. Since the conveyors are usually outside and open to all weather conditions, it is not uncommon to choose a water resistant grease to prevent water ingress.
Lubrication Frequency;
In these applications, greasing is rarely done frequently enough due to the distances between the bearings and the height above the ground. Lack of labor force may contribute to this problem.
It is conceivable to use automatic greasing systems where a centrally located reservoir feeds multiple points through pipes. However, pipelines can potentially be quite long, and such systems may require multiple systems as they will lubricate some of them.
Another alternative would be a single point grease lubricant that is directly attached to each bearing. These lubricants can be adjusted to drain grease for variable periods to suit the application and bearing size.
They can also significantly reduce the amount of effort required to grease the bearings individually, and they can help alleviate the ingress of contaminants by applying constant pressure to the bearing.
Of course, the total cost of using such lubricants throughout a facility should be weighed based on the amount of workmanship involved. Also, keep in mind that these systems should be checked on a regular schedule to make sure they are working properly. No automatic lubrication system should be applied in the “install and forget” approach.
Lubrication Reducers;
Conveyors are typically driven by different reduction gearboxes, including worm gearboxes, to allow the electric motor to sit adjacent to the conveyor and over-project. In these cases, a simple oil with a suitable viscosity can be used. The lubricant does not have to have extreme pressure properties.
Transmissions and bearings are also found in many breakers in the feed section of the quarry. These components must cope with the same problems as conveyors in terms of dust. Centralized lubrication systems are widely used here because the bearings are located close to each other, which ensures that the pipelines are not too long and are easily placed inside the grease chamber.
These gearboxes are usually quite large and have a considerable amount of oil capacity. Gear teeth often experience high shock loading, so overpressure gear oil is often used for this reason.
Crusher gearboxes greatly benefit from regular oil analysis and condition monitoring. The small oil sample required does not affect the total oil level, and information from the subsequent analysis can save considerable money to avoid unplanned downtime and consequently lost production costs.
Open Gears;
There are many different types of open gears with different lubricants and application methods associated with cement plants. The main requirement for these open gears is that the lubricant can stick to the entire revolution of the drive gear to provide the necessary protection.
This lubrication requirement occurs when the drive gear is coupled. For this reason, the best lubricants for these applications are sprayed into the threads just before the pinion and drive gear assembly. Spray pattern is critical for covering matching teeth.
Normally the lubricant is sprayed directly from a nozzle due to the amount required. The lubricant may also need a certain heat resistance and should not melt.
It can be used as long as grease and thick oils can be sprayed with adhesive additives. They must also have the ability to bear suitable loads to withstand potentially high loads to be experienced. Conventional greases are not suitable because they do not have these properties. Be sure to check your gear teeth from time to time to check for uneven wear that may indicate ineffective lubricant coverage. That's why we recommend Whitmore Envirolube XE Heavy oil for your open gear lubrication.
Rotary Ovens;
Rotary kilns have their own lubrication challenges for both bearings and gearboxes due to their slow rotation, high loads and thermal transfer of process heat. It is common for transmission oil to be used in both heat transfer systems and a circulation system that uses filtration. The oil is usually synthetic, but this is not always necessary if the flow rate is sufficient and the heat transfer system is efficient.
It can be advantageous, such as the natural friction properties and high viscosity index of certain types of synthetic lubricants. However, since greased bearings will not provide the same cooling effects, the choice of synthetic grease will probably be more important than choosing a synthetic oil for the gearbox.
In most cement plants, slow-moving conveyors, sometimes called clinker conveyors, carry the material directly from the furnaces. These conveyors are typically made of metal and consist of a series of hinged buckets. They are usually carried by wheels on guide rails with a grease nipple in the middle. Due to unfavorable working conditions, that is, dusty and hot, they often require greasing.
Central lubrication systems do not work in this type of application due to the constant movement of the wheels. A system should be installed that moves with the buckets for a short time and the lubrication probes are automatically reflected in the grease nipple. This automated system works well, but should be checked regularly due to many moving parts and associated sensors.
Large cement plants often have a limited stock of lubricants to keep lubricant application as simple as possible. Although this approach can be somehow effective, special lubricants should be considered in certain applications. Due to increased initial costs, longevity of the equipment and reduced downtime, it can save even more in the long run. Attention should also be paid to the use of synthetic gear oils in larger gear drives, as potential energy savings can be significant.
Although each cement plant operates differently and has its own existing lubrication strategies, preferences, historical problems, maintenance requirements, management structure, and current workforce, the selected lubricants can be defined as optimum solutions for the equipment and maintenance regime used to apply these lubricants.
All of these elements can then be combined with appropriate condition monitoring techniques. By coordinating both lubrication and condition monitoring strategies with your maintenance regimes, you can make your cement plant work more efficiently and cost-effectively.
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