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Product category: Lubrication - lubricants and lubrication systems
News Release from: Kluber Lubrication GB | Subject: Graphite-free lubricants for gears
Edited by the Manufacturingtalk Editorial Team on 13 August 2002

Graphite-free lubricants guard gears and
pinions

The development of so called adhesive lubricants started about thirty years ago, in order to meet requirements made by the industry.

Graphite-free lubricants safeguard gear and pinion drives The development of so called adhesive lubricants started about thirty years ago, in order to meet requirements made by the industry This type of lubricant was supposed to provide reliable low-quantity lubrication for open girth gear and pinion drives in rotary kilns and tubular mills which rarely run under ideal operating conditions

Adhesive lubricants at that time were free of bitumen, but contained lead additives, chlorine and sometimes the solvent CFC.

The graphite contained in these lubricants protected the tooth flanks even under starved lubrication conditions, however it also gave the product its opaque black colour.

In the course of time, lead additives, chlorine and CFC were eliminated.

The products did and still do their job without any problem; They have, however, remained opaque.

The trend to use modern, environmentally sound lubricants also affected adhesive lubricants, which led to the development of completely new products.

The aim was to formulate products which contained neither bitumen, lead or chlorine, nor CFC, the latter being an ozone-depleting substance.

These products should be of a light colour in order to avoid the contamination that occurs with graphite products and to enable easier maintenance of the drives and lubricant disposal.

In the meantime, partially or fully synthetic lubricants of high and very high viscosity are available on the market which are free of graphite and contain different kinds of additives.

These new lubricants are also highly adhesive and offer excellent flank protection.

Modern graphite-free adhesive lubricants achieve a load stage of 12 with a wear rate of < 0.2mg/kWh in the FZG test A 8,3/90 degC according to DIN 51354 and a welding load = 6500N in the VKA (four-ball wear test), DIN 51350, point 4.

These lubricants can be applied by spraying, immersion or circulation lubrication, depending on the operating conditions.

With spray lubrication, consumption quantities can be reduced by up to 50 % which also has a positive influence on lubricant disposal.

Experience gained in practice shows that also oscillations at the pinion bearings and tooth flank temperatures can be considerably reduced.

Another important aspect is that light, transparent lubricants make maintenance and inspection of drives much easier.

Tooth flank inspection by stroboscope is possible without having to stop the drive.

Costly and time-intensive cleaning of the drive is no longer necessary.

The transparent lubricating film makes any changes to the tooth flanks visible at once.

Disposal costs are reduced not only because of the lower lubricant quantities used, but also due to the fact that these lubricants are classified under the German directive of the Clean Air Act, class IV.

In view of the many advantages offered by light, transparent lubricants, it can be assumed that they will replace the dark, graphite products in the long run.

The selection of the adequate lubricant, however, will always be based on the specific operating and application conditions as well as on the approvals from the manufacturers of machines and drives. Request a free brochure from Kluber Lubrication GB ...

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