Sale AeroShell Grease 7
French [AIR 4210/B]
THE DEFINITION OF A GREASE IS:
"A solid or semi-solid lubricant comprising a dispersion of a thickening agent in a liquid lubricant to which various additives have been added to improve particular properties".
Within the aviation industry there are very many grease lubricated applications covering a very wide range of performance requirements which are being increasingly extended through new technology developments.
Over the years, many different formulation greases have been developed to meet specific requirements, and one of Shell’s recent objectives, as a major supplier of aviation greases, has been the development of wide
performance range products.
Greases, depending on the thickening agent, are broadly classified as either soap-based or non-soap. The soap based greases include, for example, aluminum, calcium, sodium or lithium soaps; the non-soaps silica gel, clay and substituted urea.
The low melting points of some soap greases limit their usefulness. As a result alternative thickening agents have been developed – soap-complex thickened greases, and non-soap greases with a much higher or no melting point. Non-soap thickening agents were developed for greases needing superior high temperature performance characteristics. Shell’s search for thickeners without the limitations of the soap-type, resulted in their ‘Microgel®’ technology.
Shell Companies have developed and patented an inorganic grease thickening agent, based on hectorite clay, which has been registered under the Shell trade name of 'Microgel®'. The Microgel® thickener, which does not have any of the limitations of soap type thickeners, provides the AeroShell greases in which it is used with the following excellent physical properties, making them particularly suitable for multi-purpose as well as specialised applications:
1. No melting point, within any conceivable temperature range to which aircraft greases are likely to be subjected.
2. Very little change in consistency with variation in temperature.
3. Extremely good load carrying ability without the need for extreme pressure additive.
4. Excellent water resistance due to the use of exclusive tenacious waterproofing agents developed by Shell.
5. Low oil separation or 'bleeding', because of the high gelling efficiency of Microgel®.
During recent years the number of greases required for aircraft lubrication/maintenance has been reduced by more extensive use of multi- purpose greases. However, because of commercial and technological limitations, special greases are still required. Most aircraft grease requirements are covered by the products in the AeroShell grease range.
To minimise the number of greases required per aircraft it should be remembered that by far the most widely used specification in the aviation industry today is the general purpose grease to MIL-PRF-23827.
More recently Boeing has introduced a multi-purpose grease specification (BMS 3-33) which is intended to replace many of the different greases now required in support of Boeing aircraft.
Detailed information of each AeroShell grease is given in this section, but for ease of reference AeroShell greases can be split into the following application categories.
AeroShell Grease 7 is an advanced multi-purpose grease,
composed of a synthetic oil thickened with Microgel®, possessing
good load carrying ability over a wide temperature range. It is
inhibited against corrosion and has excellent resistance to water.
The useful operating temperature range is –73°C to +149°C.