Views: 1 Author: Site Editor Publish Time: 2016-09-06 Origin: Site
There are two types of gearbox lubrication systems currently used: splash lubrication systems and force-feed lubrication. The intent of both types of systems is to distribute oil to each component of the gearbox sufficient for lubrication and cooling of that component, yet minimizing heat generation by oil churning.
Given the integral role that the lubrication system plays in the overall life and longevity of a gearbox, it must be continually maintained. This ensures the system is functioning at peak performance. It’s important to develop a systemic method of inspection, condition verification and documentation to avoid any unexpected lubrication system failures, and ultimately, equipment damage. The following are areas of concern for maintaining a properly functioning lubrication system:
- Cleanliness. Dust, dirt, grit and wear particles in the lubricant supply must be kept to a minimum. Filters and strainers should be serviced regularly to avoid circulating contaminants within the oil, as well as to avoid excessive pressure drops that can reduce the quantity of oil supplied to the gear drive.
- Lubricant condition. The service life of a lubricant is negatively affected by a number of factors, including high temperatures, water and/or emulsions, solid contaminants and operating environment. An oil sample should be drawn from the oil sump at scheduled intervals and analyzed by the lubricant supplier or a reputable maintenance provider. The lubricant supplier should be consulted for typical oil change-out limits for the particular oil used.
- Sensor/switch settings. An annual check of all switches and sensors should be performed to verify operation as per lubrication system schematic-specified settings. System vibration and environmental conditions can alter settings, ultimately affecting critical timing and initiation of sensor functions.
- Auxilary pump function. Pumps and other motorized accessories should be checked at scheduled intervals to verify operability, proper oil delivery, pressures and motor power draw. Relief-valve settings should be checked to ensure that the required oil delivery is supplied to the gear drive at the proper pressure.
- Flow and pressure check. Flows and pressure drops at the cooler, filters and inlet to the rotating equipment should be routinely monitored and recorded to identify any adverse trends that might be developing.
- Cooler condition. An annual check of cooler condition is important to maintain cooler efficiency. Water-cooled heat exchanger coolant ports should be checked for any fouling or blockage. All sacrificial anodes should be replaced. Air-oil cooler core fins should be checked and cleaned of any dirt build up that would affect heat transfer efficiency.
- Breathers. Oil breathers should be checked frequently, as they will become dirty. Any blockage in the breather could potentially lead to leakage elsewhere in the drive to relieve pressure.
- Visual component check. The entire lubrication system should be checked daily for all indicator gauge readings, pipe connections, vibration, bolted connections, oil leaks or seepage, loose accessories and wiring connections.
- Sound levels. The operating sound level of the pumps should be routinely noted. Any increase in sound level could indicate the presence of air in the lube system, blockage at the pump intake, air leaks in the pump shaft seal, worn or loose parts in the pump, filter blockage or high oil viscosity from the pumped fluid being too cold.
- Greased points. Some motors and pumps are equipped with greased bearings, which must be lubricated at manufacturer-recommended intervals.
The lubrication system plays a vital role in the successful operation of a gearbox. Continuing such success is largely dependent upon the uninterrupted supply of the proper quantity, quality and condition of lubrication oil.
Developing a systematic method of inspection, condition verification and documentation, as well as partnering with a lubrication and/or manufacturing expert that can provide further insights into lubrication system operation, is essential. This will help to avoid any unexpected lubrication system shutdowns and possible subsequent equipment damage.