General principles for the selection of equipment lubri […]
General principles for the selection of equipment lubrication materials:
1) Movement speed: high viscosity oil should be used for low speed movement and low viscosity oil should be used for high speed movement.
2) Load size: The larger the motion auxiliary load, the higher the viscosity of the lubricating oil and the better the oil.
3) Motion state: For the mechanism that starts, reverses and stops frequently, high viscosity lubricant should be used.
(4) Working temperature: When the ambient temperature is low, low viscosity, high permeability lubricating oil should be used, and at higher temperature, the opposite lubricating oil should be selected.
5) Surrounding environment: Consider whether the water and humidity are serious, how much dust, and whether there are toxic gases and other factors.
6) Clearance: The smaller the clearance of the motion pair, the lower the viscosity of the lubricating oil.
7) Hardness: The lubricating pair with high friction surface hardness should use lubricating oil with low viscosity and sufficient oil content.
8) Surface accuracy: The higher the surface precision of the moving pair, the lower the viscosity of the lubricating oil.
9) Lubrication method: High-viscosity lubricating oil should be used for manual oiling devices. Anti-oxidation additives should be used for splashing and oil mist lubrication systems.
Approximately 1,500 bearings of various modern paper machines are subject to corrosion in harsh environments, including water, heat, steam and paper dust. Each part requires special lubrication. Modern paper machines consist of at least four parts: nets, presses, dry cadres and paper rolls. Different types of paper machines produce different types of paper. We recognize different lubrication requirements depending on the product and machine speed.
When the pulp enters the portion of the paper machine, the web, it contains about 99% water. At the end of the web, paper is formed substantially. This forming process is a process of dehydrating a large amount of paper. When it enters the printing section, the paper has been formed.
Therefore, the mesh of the paper machine used in modern factories is immersed in a large amount of water, and in most cases, the bearings in the net must be lubricated with butter. Butter has the function of sealing, waterproofing and removing impurities, especially for bearings. One way to lubricate mesh bearings is to use an automated system to pump the prepared butter into the bearing every day. This method ensures that the new grease is used to clean the bearings on a regular basis.
Sometimes, some lubricants choose oil instead of butter as the lubrication of the net bearing, which may be caused by one or more reasons. For example, in high-speed networks where operating temperatures continue to rise, bearings may require too much lubricant to lubricate, while good lubricants may be more economical and cleaner. When oil lubrication is selected, the bearing must use an oil seal that matches the oil.
In general, the choice of mesh bearing lubricants is a high quality lubricant with artificial viscosity and good water resistance. At the same time, corrosion resistance is also a factor in the choice of mesh lubricants. Therefore, both butter and oil must contain good anti-rust ingredients.
When the paper enters the press section, it contains 80% moisture, while the press section squeezes excess water out. Pressing is a more economical method of removing paper moisture than steam heating, and it also improves the quality of the paper. Therefore, pressing methods have been widely developed in paper machines.
Especially in the news department and the network department, water is a problem, but calories are not. Therefore, butter and oil are usually used in the pressure portion of the bearing. The type of lubrication selected is usually determined by the bearing specifications and speed. For butter lubrication, multi-stage composite seals help prevent water ingress, while water-insulated covers prevent water from entering when the hose is dropped.
Circulating oils are typically used for relatively high speed bearings because braking problems can occur when lubricating with grease at higher speeds. In addition, in high speed paper machines, the large bearings on the press rolls generate a relatively high amount of frictional heat, requiring a large amount of circulating oil to flow and dissipate heat. Reducing the inlet temperature and installing a separate cooling tank helps maintain the desired circulating oil viscosity. In press roller bearings lubricated with circulating oil, the oil seal prevents oil from flowing out of the frame and the multi-stage oil seal is waterproof. Regardless of the type of lubricant, rust inhibitors are an integral part.
There is a reason for oil lubrication on the felt roll of the press section. When the line speed is fixed, the smaller the roller diameter, the higher the speed. If the high-speed rolling bearing is lubricated with butter, the operating temperature of the rolling bearing will be high. If lubricated with butter, the amount of butter will be large and excess butter may contaminate the equipment.
Please note that oil-lubricated bearing oil seals are not as effective as butter multi-grade oil seals. In addition, the oil lubricated bearings on the pressure section must be sufficiently effective since the oil lubricated bearings are immersed in the water during operation and descent.
When the paper comes out of the press part, it usually contains less than 50% of water, and then enters the dry cadre to remove excess water, so that the water is reduced to 5% ≤ 10%.
Bearings are exposed to high temperatures for a long time in dry cadres, and the working environment of these bearings is quite harsh. With the rapid development of modern equipment, the challenges of lubricating oil and lubrication transmission systems are increasing. Because of the rapid development of modern equipment, equipment is constantly moving to large-scale, high-speed and automated, larger machines, faster speeds and higher speeds. The temperature of the steam.
There are many types of rollers for dry cadres, such as drying cylinders, which are used to drive paper and are immersed in water vapor. Steam heating increases the temperature of the drying cylinder depending on the production and mechanical speed. In many cases, even with an insulating ring, the bearing temperature can reach 125 degrees Celsius. The drying cylinder is the same as the press section, and there is also a felt drive roller. They are used to dry paper.
The dry parts of the bearings such as drying drums, dry wire rolls, and rollers are generally lubricated with circulating oil. There is usually a special oil station, which is lubricated with oil and is determined according to the requirements of the environment in which the bearings of the dry cadres are located. Lubrication of dry cylinder bearings requires a large amount of waterproof oil of appropriate viscosity. In order to properly lower the temperature of the drying cylinder and prolong the service life of the bearing, in the high temperature environment, a heat insulating ring appears in the equipment. Modern machines with insulated rings typically reduce the temperature of the bearing to less than 90 degrees Celsius.
There are many factors that affect the flow of lubricants. According to the different requirements of different equipments, with the development of equipment diagnostic technology and detection technology, a new type of computer analysis and detection technology has emerged, which can solve the lubricating oil problem through computer analysis, including equipment lubrication flow and lubrication status.
With the continuous development of equipment, the scale is getting larger and larger, and the width of large paper machines can now reach more than 10 meters. Before selling paper, you must cut the paper into small rolls. As the coiler continues to increase during the operation of the coiler, the weight of the coiler, including the coiler, gradually increases. Finally, the reel weight that meets the reel requirements can exceed 100 tons. Then, the reel is required to cut the reel into a small reel that the customer needs. For such a large weight, on the reel. In this device, the most important thing is to roll the paper onto the bearing on the paper tube.
Compared to the other parts of the paper machine, the reel bearings are in a relatively good working environment, dry, low temperature, about 25 degrees Celsius. However, these bearings must be protected from paper dust.
The relative rotational speed of the paper roll machine is slow, especially in the case where the paper roll is continuously increased, the rotational speed is gradually reduced. Butter is mainly used for lubrication of the shaft. Many manufacturers are now using circulating oil to lubricate these bearings, and the use of a unified circulating oil system, especially large machinery and equipment, is becoming more common, so it is necessary to ensure that sufficient oil is provided for both purposes. When lubricated with butter, the bearing lubrication of the web machine can use the same butter as the net and press. Lubrication is done about once a month.