For anyone who works in a paper plant, you know you work with some serious, heavy-duty machinery, and those machines are subjected to extreme operating conditions. Modern papermaking machines are often more than 30 feet wide, 60 feet tall, and more than 600 feet long, with each machine being comprised of thousands of different moving parts. Factor in the extreme humidity, chemicals, water, and paper dust generated during the papermaking process, and it’s easy to see why good lubrication is necessary to keep these complex machines working.
Moisture in lubricating oils is a significant and primary factor associated with the root cause of prematurely damaged oil and the accelerated wear of machine components in paper plants. In order to protect machinery from the harsh, humid paper plant environment, use specifically formulated machine oils designed to withstand heat and separate from water. Of course, the type of fluid you need—oil or grease—to defend against heat, water, and corrosion depends on the production point and other factors.
To help you know which fluid is necessary for each section of the machine, consider these lubrication best practices and 8 types of lubricants commonly used in paper processing plants.
Paper Plant Lubrication Best Practices
Each papermaking machine can be broken down into four sections: a forming section, press section, dryer section, and reeler. In each section, different parts of the machine perform special tasks that are vital to the papermaking process. In order to ensure your machine is operating at its fullest potential in each section, specialized lubricants are required to optimize machine performance. To help give you a better idea of which lubricants work best in each section, follow the tips below:
Forming Section/Wet Section
The first part of the papermaking process starts at the forming section, where wet pulp is placed on the paper web to drain its water content. When pulp enters the machine here, it’s roughly 99% water. Because so much water is involved in this part of the process, heat usually isn’t a factor when determining which lubricant would be best. With that in mind, bearings in this section are typically best lubricated with grease to keep out water and purge contaminants. If oil is used instead of grease, be sure to select compatible bearing seals. Whether you use oil or grease, however, both should have good corrosion preventing properties and be formulated with the necessary additives to help control the amount of water that reaches lubricating surfaces.
After going through the forming section, the paper web is sent through the press section with its water content at about 80%. Here, even more water is pressed from the pulp. And while heat may become more of a factor in this section, water is still the primary concern. The type of lubrication here will depend on the size and speed of the bearings and rolls, as well as operating temperatures. For large bearings that rotate relatively fast, oil is preferred to help dissipate the heat caused by friction, as well as prevent skidding problems commonly associated with grease.
Once the paper web leaves the press section, its water content is around 50%. By the time it leaves the drying section, however, it will be down near 5-10%. In order to dry the paper here, bearings are exposed to temperatures as high as 257°F over long periods of time, not to mention steam acting as a potential corroder. To help keep temperatures down, it’s important that your oil is water-free and the appropriate viscosity. To ensure that it is, your fluid supplier should be able to run a computer analysis that determines the ideal oil properties for your operating environment.
Now that the paper is dry, the web is sent to the reeler where the finished paper is rolled up on a spool for collection, cutting, and shipment. These gigantic rolls of paper can weigh up to 100 tons, meaning relatively slow rotations for the bearings, but with a heavy load. Compared to other sections of the machine, these bearings are much better protected from water, heat, and other damaging elements, but still require protection from paper dust and heavy loads. In most cases, grease is used for the reel-drum bearings, but if you have a circulating oil system in use already, circulating oil is another reliable option. It is worth noting, however, that the bearing arrangements for the reel-drum can often be lubricated with the same grease as the forming and press sections.
8 Types of Lubricants Commonly Used in Paper Processing/Production Plants
Now that you know a little more about the lubrication best practices for different sections, here is a quick overview of 8 common lubricant types you should consider for your own paper processing/production plant:
1) Synthetic Gear Oil — Used in gearboxes of the tank agitator, wet & dry sections, size press & coatings, and in the circulation system of the calendar stack.
2) Premium EP Gear Oil — Used in gearboxes of the tank agitator, wet & dry sections, size press & coatings, and in the circulation system of the calendar stack.
3) Industrial Greases — Used in electric motors, tank agitator, and pump bearings, as well as pump motors, dryer bearings, exhaust fan motor bearings, and the winder.
4) Electric Motor Bearing Grease — Used in the electric motors of the tank agitator, wet & dry sections, exhaust fan, and size press & coatings.
5) Paper Machine Grease — Used in wet section bearings, press roll and felt roll bearings, dryer bearings, size press & coatings bearings, and the winder.
6) Paper Machine Oils — Used in gearboxes of the tank agitator, wet & dry sections, size & press coatings, pump & wet section bearings, press stack, and circulation systems in wet, press, and dryer sections.
7) Premium Zinc-Free Hydraulic Circulating Oil — Used in circulation systems in the wet section, press section, dryer section, and calendar stack.
8) Other Specialty Oils — Used in various applications, from couplings & bearings for tank agitators, to press/production & coatings.
Of course, choosing the ideal lubricant and formulation for your specific operating environment requires a little more information and knowhow, but that’s where we can help. At U.S. Lubricants, we offer a wide variety of high-quality lubricants used in paper plant machinery, and our expert lubricant technicians will work closely with your team to ensure the perfect formulation for your plant’s needs.
Not sure where to start? Our handy, at-a-glance cheat sheet can help you identify the right lubricant for your paper plant equipment. Download it below, and contact Tony Springer at TSpringer@uslube.com or by phone (800) 490-4900 ext. 8823 if you have any other questions.