Selecting the best lubrication method for your PT operations can help maximize both the life and operational efficiency of your roller chain
Proper lubrication is essential for a chain drive to achieve its potential design life. In fact, the type of lubrication employed may be the sole limiting factor in determining the horsepower capacity of a chain drive. Lubrication combats roller chain wear caused by bearing pressure, angle-sliding movements of the pins and rotation of the rollers by…
- Impeding rust and corrosion
- Lubricating the pin bushing joint and chain sprocket contact point
- Cushioning impact loads
- Dissipating heat
- Flushing away foreign matter
There are five primary roller chain lubrication methods: manual, drip, oil bath, oil-ring and force-feed. Selecting the best lubrication method for your chain depends on various factors, such as: operating temperatures, chain speed, the working environment of the chain, cost and other various preferences.
1 – Manual Lubrication
This type of lubrication is done using an oil can, aerosol spray and brush, and requires someone to manually add lubricant into the gap between the inner and outer link plate of the loose side of the chain. This method should be done at least once a day (or once every 8 running hours).
Removing the chain guard to apply lubrication mid-operation can be dangerous. Therefore, it is only recommended if machinery is shut down at regular intervals for maintenance or for machinery with secondary drives/low chain speeds.
“While manual lubrication is the most cost-effective option for roller chain lubrication,” says Tim Zerger, IBT Director of Bearings and Power Transmission, “it is the least desirable. It reduces productivity, leaves more room for human error and has a higher potential for injury.”
2 – Oil Bath Lubrication
In an oil bath lubrication, the chain is installed in an enclosure and the bottom of the chain is fully immersed in a pool of oil. The immersion should not be too deep or too shallow as it may cause the oil to heat up and lead to untimely oxidation of the oil.
“Because the oil is maintained within the casing, a well-sealed drain plug is crucial to avoid leaking,” says Zerger. “This is the most effective method of lubrication because you can guarantee that the whole chain is being thoroughly lubricated.”
3 – Drip Lubrication
Wick oilers, needle oilers or drip oilers, where oil from the oil cup is supplied by drip feeding, are only suitable for low bearing pressure drives. The standard procedure is to apply 5-20 drops of oil per minute for every strand of chain (quantity depends on the speed).
According to Zerger, this method of roller chain lubrication is ideal for machinery with spatial constraints because you can feed the oil to the location you need with a hose from an external source. However, similarly to the oil bath, if the drain plug is not sealed well, the oil can leak out and create a mess.
4 – Oil-Ring Lubrication
In oil-ring lubrication, the chain operates above oil level, while a disk is submerged into the lower oil level. The disk centrifuges oil against the casing walls from where it continuously runs down onto the chain via drip rails. The disk should be mounted on both sides of the sprocket and also requires a leak-free enclosure. Additionally, this method of chain lubrication is only effective at speeds in excess of 300 RPM.
“While this method doesn’t apply oil as effectively as an oil bath, it is sometimes more practical and economical than using an enclosure,” says Zerger.
5 – Force-Feed Lubrication
In force-feed lubrication, an oil pump and oil feeding pipe supplies a continuous spray of oil to the inside of the lower span of chain to ensure the circulating cooling of the chains. The spray nozzles should be near the gearing places of the chain and sprocket, and the nozzle number should be more than the chain strands number to make them aim at the gap of each row link plate.
“This method is recommended for large horsepower drives, heavily loaded drives, high-speed or where other types of lubrication cannot be used or are ineffective. The spray nozzle gives you control to direct the spray exactly where you want; however you have to be sure that it’s not spraying outside the guard, causing leakage,” says Zerger.
Though this is the most costly method, it is also the most effective for extracting the greatest performance and life out of the chain drive. Learn more about other best practices for optimum roller chain performance here.
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