Question on Why Sealed Spherical Roller Bearings

First, let us assume that the average number of belt conveyor pulley drums per cement plant is 100. This is based on the fact that there are many types of belt conveyors used in the cement industry, such as long belt conveyors, pipe conveyors, bucket elevators, apron conveyors, etc. Each belt conveyor may have several pulley drums, depending on the length, configuration, and tensioning system of the conveyor. For example, a long belt conveyor may have a drive or head pulley, a tail pulley, a bend pulley, a snub pulley, and a take-up pulley. A pipe conveyor may have a head pulley, a tail pulley, and several transition pulleys. A bucket elevator may have a head pulley, a boot pulley, and a counterweight pulley. An apron conveyor may have a drive pulley, a tail pulley, and a snub pulley. Therefore, the number of pulley drums per conveyor may vary from 2 to 6 or more. Assuming an average of 4 pulley drums per conveyor, and an average of 25 conveyors per cement plant, we get 100 pulley drums per cement plant.

Second, let us assume that each pulley drum has two spherical roller bearings, one on each end of the shaft. This is a common arrangement for pulley drums, as spherical roller bearings can accommodate both radial and axial loads, and have high load carrying capacity and speed capability. Spherical roller bearings are also suitable for harsh environments, such as dust, heat, and vibration, which are common in cement plants. Therefore, the total number of spherical roller bearings per cement plant is 200.

Third, let us assume that the current spherical roller bearings are open type, meaning that they require periodic lubrication and maintenance. According to this source, the typical service life of open spherical roller bearings in cement plants is 12 months, and the typical grease consumption is 0.5 kg per bearing per month. Therefore, the total grease consumption per cement plant is 1200 kg per year, and the total number of bearings that need to be replaced per year is 200.

Fourth, let us assume that the sealed spherical roller bearings have twice the service life and half the grease consumption of the open spherical roller bearings. This is based on the fact that sealed spherical roller bearings have better protection against contamination and lubricant leakage, and therefore require less maintenance and lubrication. According to this source, sealed spherical roller bearings can reduce the total cost of ownership (TCO) by reducing maintenance and increasing service life. Therefore, the total grease consumption per cement plant with sealed spherical roller bearings is 600 kg per year, and the total number of bearings that need to be replaced per year is 100.

Fifth, let us assume that the average cost of a spherical roller bearing is $100, the average cost of grease is $10 per kg, the average labor cost for replacing a bearing is $50, and the average downtime cost for a conveyor is $1000 per hour. These are rough estimates based on some online sources, and may vary depending on the size, type, and quality of the bearings, grease, and labor, as well as the production capacity and efficiency of the cement plant. Therefore, the total cost of using open spherical roller bearings per cement plant per year is:

(200×100)+(1200×10)+(200×50)+(200×1×1000)=260,000

The total cost of using sealed spherical roller bearings per cement plant per year is:

(100×100)+(600×10)+(100×50)+(100×1×1000)=135,000

Therefore, the total savings of using sealed spherical roller bearings per cement plant per year is:

260,000?135,000=125,000

This means that changing the spherical roller bearings from open to sealed type can result in a 48% reduction in the total cost of ownership (TCO) per year. This also means that the bearing life can be increased by 100%, the grease consumption can be reduced by 50%, the labor cost can be reduced by 50%, and the downtime can be reduced by 50%.

Of course, these are only rough estimates based on some assumptions and averages, and the actual savings may vary depending on the specific conditions and parameters of each cement plant. However, I hope this answer gives you some idea of the potential benefits of using sealed spherical roller bearings in cement plants.