The Right Match
The right match
When specifying a chain for a particular application, key considerations include efficiency, reliability, and, crucially, cost. Often, lubrication doesn't feature in this list, which is an oversight, as it plays a critical role in a chain’s performance.
For example, when a roller chain is lubricated correctly, Renold select them to typically last at least 15,000 hours on most applications. Without it, the chain will wear rapidly, compromising operation and damaging profitability.
With lubrication having such a significant effect on a chain’s performance, it is important to understand the range of lubrication options available. Here, we outline five common methods, while giving examples of their typical use cases. The method used generally depends on chain speed and load or power when selected in accordance with Renold’s chain rating charts.
1. Manual lubrication
It is possible to lubricate chains manually, but this method is usually only recommended in special instances because it can be time-consuming, inefficient, expensive, and error-prone. The lubricant is applied to the chain using a brush or oil can straight to the spaces between the inner and outer plates, where the chain connects with the sprocket. The challenge is to ensure that the oil penetrates the joints; otherwise, it won't be able to lubricate the bearings sufficiently. Unfortunately, to ensure safe continuous operation, the process needs to be repeated approximately every eight hours, resulting in frequent downtime.
- Low intensity drives in general purpose applications
- Non-critical drives with low loads and speeds
- Environments where excess lubrication is of no great concern
- Low duty or rarely used drives
2. Drip lubrication
Drip lubrication is typically recommended for chains operating at relatively slow speeds, ranging between 1.5 to 8 m/s. In this method, the oil is applied by a drip oiler, which automatically inserts the oil between the inner and outer plates. However, the process needs to be targeted carefully, as the oil can only penetrate the internal components to protect the bearing surfaces if it is applied to the very edges of the chain. The oil reservoir must also be checked regularly to ensure adequate flow of lubricant, determined by the speed of the chain.
- Slow speed general purpose drives for conveyors, etc where manual access is limited or in an unsuitable human environment
- Higher load and speed applications
- 24 hour running applications
3. Bath lubrication
This is an effective option for applications operating at moderate speeds. As the name describes, bath lubrication involves running the chain through an oil bath, either in the drive housing or using a slinger disc, which picks the oil up from the sump and deposits it on the chain. It is also good to bear in mind that to benefit from bath lubrication, the chain plates need to have circumferential speeds between 180 and 2240m/minute.
- High speed drives in automation system with enclosed drives which are difficult to access
- High load systems with high power motors
- Smaller sized chains operating at high speeds
- Large chains operating at lower speeds such as automotive drives
4. Stream lubrication
This method is especially suitable for applications where the chain operates at high speeds because as well as adequate lubrication, it also provides cooling and shock absorption. Sometimes also called force-feed lubrication, it features a continuous stream of oil which is sprayed from the pipe onto the chain. It is an effective way of spreading the lubricant, as long as the nozzles direct the spray to the edge of the chain. It can also help dampen the damaging impact of the rollers on the sprockets' teeth, reducing wear.
- Extreme high speeds with high loads and high power
- Heavy duty high speed drilling
5. Lubrication-free options
While operators can usually find a suitable method of lubrication from the above options, some applications make the use of lubricants impossible. In many food manufacturing processes, for example, manufacturers can't take the risk that the lubricant contaminates the product. That's why leading manufacturers offer lubrication-free chains, that have been developed to provide optimal performance without any lubrication. Renold's Syno NP chain, for example, delivers the lubricant only when the chain is running using a purpose-designed sintered bush. As soon as the chain stops running, the lubricant returns to the bush, eliminating any chance of contamination. Other lubrication-free methods include using chains featuring inner links with bush inserts made of polymer such as Renold Syno PB: these chains often require no lubrication at all.
As these examples demonstrate, a range of solutions exists to help operators optimise their application and reduce downtime, unplanned maintenance, and other risks to profitability. A consultation with the chain manufacturer, when specifying the chain, will help ensure that sufficient lubrication is achievable for the chosen option. To find out more, visit /support/chain-info-index/