The traditional method of using a grease gun to purge a bearing until the grease runs out of the seals is now a thing of the past thanks to a new automated grease pump from Hove of Denmark. A first for the South African market, the new technology is being distributed exclusively by wear-control specialist Filter Focus.
The Hove automated grease pump has been designed specifically to place small or large quantities of grease in an application as accurately and as quickly as possible, without any contamination entry in the process, Filter Focus Chief Operating Officer, Craig FitzGerald, explains.
Traditionally, most industrial customers have a large pail of grease that stands open. If you rub your fingers through this grease, a colour change will occur due to the commonly seen layer of dust contamination. Dirty hands are generally used to place contaminated grease into a dirty grease gun. In addition, the process of actually purging a bearing with grease using a grease gun is both physically arduous and time-consuming, wasteful and unnecessary.
“Everyone involved in greasing operations in South African industry has been taught to purge grease until it comes of the seals. This is simply the way that things have been done until now, despite the fact it is wasteful and also detrimental to bearings.
“A bearing has fine tolerances. Fill it with contaminated grease, and bearing life will be severely shortened,” FitzGerald points out. “This effectively leads to unnecessary wearing of the lubricated surfaces of the bearing and race, and condemns your equipment to a very short service life with regular unplanned stoppages.
“People simply do not understand the implications of this. Further unknown are the safety risks as many modern synthetic greases can be toxic, which means that skin contact must be avoided at all times.”
FitzGerald paints a picture of a mine carrying out routine maintenance, which requires an entire plant shutdown, followed by workers carrying out greasing operations manually over a three-day period. With the new Hove automated grease pump, these three days can be reduced to a matter of hours.
The secret to the automated pump is that it uses grease cartridges prefilled under highly hygienic factory conditions in Denmark. The cartridges are available in 1 500 ml, 3 000 ml and 5 000 ml sizes, and are very easy to replace and interchange. The entire pump unit weighs only 13 kg, has wheels for easy transportation, and can even be carried in a backpack for maximum flexibility on-site.
Apart from contamination, the major disadvantage of the traditional grease-gun method is that invariably far more grease is used than what is necessary. “There is significant wastage in industry,” FitzGerald stresses. The new Hove automated grease pump not only provides the exact amount of lubricant required, but also means bearings benefit with a much longer lifespan, with improved performance, reliability and availability – which all translates into reduced downtime, longer Mean Time Between Failures (MTBF) and improved efficiencies.
“It is important to note that over-lubrication of bearings has many negatives. Consider the energy required if you were walking on the beach ankle deep in water. If you walked deeper in until the water was near the top of your chin, considerably more energy would be required to do the same work.
In general, only a third of a bearing should be filled with grease. Lubricant churning not only means that the bearing has to work harder, but temperature increases occur through friction. This can cause grease to melt, and run out of the bearing.”
FitzGerald explains that the correct method to lubricate a bearing is to look at the bearing size, rotational speed and load. These are the main factors that need to be taken into account in terms of the lubrication frequency and the quantity of lubricant that is required. A slow-moving, heavily loaded bearing requires more lubricant with more frequent lubrication, whereas a high-speed bearing needs less lubricant, less frequently.
Purging a bearing with a grease gun until grease comes out of it also runs the risk of bearing failure. “Workers want to get the job as done as quickly as possible, and purge the grease too quickly, which increases the internal pressure and could cause the seal to blow out,” FitzGerald cautions.
Instead the Hove automated grease pump can be connected straight to the bearing, and the precise quantity of lubricant required inputted and injected. An added benefit is that the speed of the pump can be changed accordingly, from 20% up to 100%.
“If you have 100 bearings on a plant requiring the same quantity of grease, which is generally the case, then you can input these parameters into the Hove automated pump, thereby reducing the time required for lubrication significantly,” FitzGerald highlights. The Hove easy carry grease system provides, pre-programmed or one-touch user settings for simple operation.