Ever wonder why your lubrication is causing so many bearing failures? Maybe it''s due to the use of inferior quality grease. Or a lack of resistance to contaminants. Maybe it''s the age of the grease, or even poor grease analysis.
Actually, you may be asking the wrong question. Rather than, "What''s wrong with the lubrication I''m using?" a more appropriate question might be, "Is my lubrication being applied correctly?" In fact, more and more maintenance people are recognizing that it''s as important to understand how much and how often lubricant should be delivered as it is to know the type. As a result, newly designed, single-point automatic lubricators are taking the worry -- and maintenance -- out of bearing lubrication.
Very often the name of the game in manufacturing productivity is preventive maintenance; that is, carrying out maintenance that can be performed economically in order to prevent equipment breakdowns before they occur. Considering that nearly 90% of all bearings are lubricated with grease, and that 80% of all bearing failures are lubrication related, a crucial aspect of preventive maintenance is ensuring that your bearings are maintained at proper lubrication levels, with adequate grease to help keep out water, dust, and other contaminants.
Unfortunately, in many applications proper lubrication is not the highest priority on some maintenance agendas, often due to the inaccessibility of bearings or because they cannot be lubricated until the equipment stops operating. Needless to say, potential danger sometimes lurks when trying to reach relatively inaccessible bearings while equipment is operating, oftentimes reason enough -- in the eyes of some -- for bearing lubrication to go unchecked. At the same time, grease amounts can be a nagging problem, with over-greasing or under-greasing a potential cause of bearing failures.
For the most part, there are three basic approaches to providing lubrication in applications: manually; through a centralized lubrication system; and through single-point automatic lubrication.
Manual lubrication sounds simple enough in theory, yet carrying it out properly and reliably is not quite as simple as you might think. Extreme diligence must be taken on the part of your maintenance team to ensure that each bearing application receives the right amount of grease at the proper operational intervals. Manual lubrication increases costs, since it requires a person dedicated to lubricating each bearing application.
Centralized lubrication systems, on the other hand, while more reliable, are also quite expensive and typically are most cost-effective only if you have numerous lubrication points grouped in relatively close proximity to one another using the same type of grease.
Next Generation Automatic Lubricators
The solution was clear to FAG Bearings: offer a virtually maintenance-free lubrication device that is cost effective and easy to install; one that guarantees a lubrication schedule that reliably introduces fresh lubricant based on the precise needs of the application. (As pictured, device can be installed on just about any application requiring regular greasing.)
There are numerous advantages to adopting automatic lubricators to your equipment maintenance schedule. From a maintenance-engineering standpoint, the benefits of a single-point automatic lubricator include:
- Guaranteed continuous and controlled lubrication flow
- No temperature increase during lubrication
- Continued lubrication in dangerous areas during machine operation
- No introduction of foreign particles in lubrication line
- Bearings in hard-to-reach, forgotten areas will be relubricated
- Longer maintenance intervals
- Reduced grease consumption (more efficient use of the lubricant)
- Improved operating time/decreased downtime
- Quick return on investment from lower repair/maintenance costs.
FAG, for example, offers two different models, an electrochemical unit and one that is motor driven, in order to satisfy specific customer requirements. These units were designed after market research confirmed that traditional automatic lubricators were either not performing at optimum levels in the field, or that manufacturers of the devices were not assisting customers with proper setup. (Automatic lubricators are an easy solution for lubricating in hard to reach or dangerous areas, as illustrated.)
Electrochemical Units
The electrochemical automatic lubricator operates on a bladder principle, where the bladder expands inside its housing through the formation of gas. An activator screw in the rear of the unit drops a pellet into a liquid electrolyte to create up to 65 psi of pressure through a chemical reaction. This pressure causes the bladder to push a piston forward and continuously dispense grease into the lubrication point. The length of time it takes to empty the unit (which holds approximately 120 cc of grease) is controlled by the use of different activating screws -- offering one, three, six, and 12 month lube periods -- and allows for precise and continual lubrication. The activation screws, as well as the ambient temperature, determine how rapidly the chemical reaction builds up pressure and, therefore, how quickly the lubricant is dispensed.
The FAG Compact and Compact Polar units are made from sheet metal and will not allow any of the gas to escape. Even still, it is important to note that the gases formed are completely safe, and the unit can be discarded as any other non-hazardous item. As a special offering to meet food industry standards on washdown requirements, Compact Clear, a plastic electrochemical unit, is available as well. However, over time, some of the gases may be lost through permeation of the plastic housing, so it is recommended that this plastic unit not run for more than six months.
When to use gas-driven units: electrochemical units are affected by temperature, since the gas will expand faster under hot conditions and therefore will expel the grease at a faster rate than in colder temperatures. However, the activating screw can be changed to ensure that the unit works in temperatures from -13°F to 104°F. Also, it must be remembered that these units contain a fixed amount of grease, 120 cc (1 cc is approximately .9 g of lubricant, depending on lubricant density), and are disposed of once the grease has been dispensed. Although gas-driven units can function in virtually any position -- including under water and in explosionproof environments -- the remotely mounted type can extend no more than six feet from the lubrication point.
Electromechanical Units
This second category is a system that consists of a reusable, battery-powered motor unit and a replaceable lubrication canister. Each of these units can be easily set for different discharge periods and be turned on and off with a switch. The electromechanical units are temperature independent and have very precise discharge periods. The motor has two dip switches, one for determining the volume of grease that can be attached to the device (60 cc, 120 cc or 250 cc), and the second switch regulating the discharge time period. Once the unit is set and turned on, a red light will appear, followed by a green light indicating the unit is on and operating error free. This electromechanical unit also has a self-check capability, with the "intelligence" to issue a warning when the unit is out of grease or if there is a problem delivering lubricant.
One of the major advantages of this motor-driven automatic lubricator is that it will ensure that the discharge cycle is reliable and that the same amount of grease is delivered every time. Once switched on, the motor activates the gear set which, in turn, is connected to a threaded spindle on which a piston rides. The piston immediately builds to 75 psi pressure and begins dispensing the grease. As indicated, the reusable motor will drive any of three lubricant canisters -- 60, 120, and 250 cc -- and can be set to different discharge periods depending on any future change in lubrication requirements.
As an example, a 120 cc unit might be programmed for three months of lubrication, and set to discharge grease every 4 ½ hours, or roughly 1.33 cc of lubrication/day. Certainly, when evaluated properly, a little lubrication goes a long way. Yet, strategically, more frequent lubrication with lesser amounts could conceivably eliminate friction caused by insufficient grease, while slightly reducing the amount of lubricant could help reduce heat buildup. It''s this precise delivery of grease that results in the many benefits offered by automatic lubricators, the most important being extending the life of bearings and reducing downtime for your operation. Electromechanical lubricators can be remotely mounted up to 12 feet from your equipment -- allowing you to place it in a more convenient location -- although it must be positioned between a 90 and a 270 degree angle and can only be used in a non-explosive environment.
Automatic lubricators can be applied to just about anything that requires a steady flow of grease, and can even be utilized as a smaller version of a complete central lubricating system delivering grease to multiple points without an outside supply of energy or controls. Its grease can be applied in a preset, controlled fashion to the following industries:
- Pulp & Paper
- Aggregate
- Cement
- Metal (steel, aluminum)
- Agriculture
- Petrochemical
- Mining
- Wind Power
- Automotive
- Power Generation
- Phosphate
- Food Processing
- Water/Waste Water Treatment
- HVAC
- Oil
- Facility Management
- Chemical
- Textile
Applications include:
- Fans
- Conveyors
- Gear Boxes
- Blowers
- Shaker Screens
- Pumps
- Electric Motors
- Chains
- Compressors
Adjustable Lubricators
FAG continues to work on enhancing the efficiency and convenience of automatic lubricators. A system is presently under test where the technology will enable these relatively inexpensive devices to "read" a lubrication scenario and adjust the delivery level of grease accordingly. The advantages of this technology are obvious, including virtually worry-free maintenance and longer service life of bearings and operating equipment.
The design and reliability of today''s automatic, single-point lubricators make them an important component of preventive maintenance. These very useful and cost-effective devices -- no longer limited for use in hard-to-reach areas, but rather, in critical lubrication areas as well -- offer a simplicity and long-term cost savings that cannot be ignored. They provide maintenance personnel with the kind of flexibility and choices that can only make decisions easier and more timely.