Use and Maintenance of Paper Machinery Equipment
General principles for selecting lubricating materials for equipment:
1) Motion speed: High-viscosity lubricant should be used for low-speed motion and low-viscosity lubricant should be used for high-speed motion.
2) Load size: The bigger the motion pair load, the higher the viscosity of lubricating oil, the better the oil.
3) Motion state: High viscosity lubricating oil should be selected for frequently starting, reversing and stopping mechanisms.
(4) Working temperature: At lower ambient temperature, low viscosity and high permeability lubricants should be selected, while at higher temperatures, opposite lubricants should be selected.
5) Ambient environment: Consider whether water and humidity are serious, how much dust, whether there are toxic gases and other factors.
6) Clearance: The smaller the clearance of the pair, the lower the viscosity of the lubricant.
7) Hardness: Motion pairs with high friction surface hardness should use lubricants with low viscosity and sufficient oil content.
8) Surface Accuracy: The higher the surface accuracy of the pair, the lower the viscosity of the lubricating oil.
9) Lubrication mode: Artificial refueling device should generally use high viscosity lubricating oil, splash and oil mist lubrication system should use antioxidant additives.
About 1500 bearings of various modern paper machines are corroded in harsh environments, including water, heat, steam and paper dust. Every part needs special lubrication. Modern paper machines consist of at least four parts: nets, press, drying cadres and paper rolls. Different types of paper machines produce different types of paper. According to different products and machine speeds, we recognize different lubrication requirements.
When the pulp enters the part of the paper machine, that is, the mesh, it contains about 99% water. At the end of the net, paper is basically formed. This forming process is the dehydration of a large amount of paper. When it enters the printing department, the paper has been formed.
Therefore, the meshes of paper machines used in modern factories are immersed in a lot of water, and in most cases, the bearings in the meshes must be lubricated with butter. Butter has the functions of sealing, waterproofing and removing impurities, especially for bearings. One way to lubricate mesh bearings is to pump the prepared butter into the bearings every day using an automatic system. This method ensures regular use of new butter cleaning bearings.
Sometimes, some lubricants choose oil instead of butter as the lubrication of net bearings, which may be caused by one or more reasons. For example, in a high-speed mesh, the working temperature keeps rising, bearing may need too much lubricant to lubricate, and a good lubricant may be more economical and cleaner. When selecting oil lubrication, bearings must use oil seals matching oil.
Generally speaking, the choice of mesh bearing lubricant is high quality lubricant with artificial viscosity and good water resistance. At the same time, corrosion resistance is also a factor in the selection of mesh lubricants. Therefore, butter and oil must contain good rust-proof ingredients.
When the paper enters the press section, it contains 80% water, while the press section extrudes excess water. Pressing is a more economical method of removing moisture from paper than steam heating. It also improves the quality of paper. Therefore, pressing methods have been widely developed in paper machines.
Water is a problem, especially in the news and Internet sectors, but heat is not. Therefore, butter and oil are usually used in the pressure part of bearings. The type of lubrication selected is usually determined according to the specifications and rotational speeds of the bearings. For butter lubrication, multi-stage composite seals help prevent waterproofing, while water insulation caps prevent hoses from falling into the water.
Circulating oil is usually used for bearings with relatively high rotational speeds, because braking problems may occur when lubricated with butter at higher rotational speeds. In addition, in the high-speed paper machine, the friction heat generated by the large bearing on the roller is quite high, which requires a large amount of circulating oil to flow and heat dissipation. Lowering the inlet temperature and installing a separate cooling chamber help to maintain the required circulating oil viscosity. In the squeezing roller bearing lubricated with circulating oil, oil seal can prevent oil from flowing out of the rack, and multi-stage oil seal can be waterproof. No matter what kind of lubricant, rust inhibitor is an indispensable component.
There is a reason why there is oil lubrication on the wool rollers in the press section. When the online speed is fixed, the smaller the roll diameter is, the higher the speed is. If high-speed rolling bearings are lubricated with butter, the working temperature of rolling bearings will be very high. If lubricated with butter, the amount of butter will be very large, and excessive butter may contaminate equipment.
Please note that oil-lubricated bearing oil seals are not as effective as butter multi-stage oil seals. In addition, since oil-lubricated bearings are immersed in water during operation and descent, the oil-lubricated bearings in the pressure section must be sufficiently effective.