Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Processes of purifying or recovering used lubricant...
Reexamination Certificate
1999-12-23
2001-02-20
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Processes of purifying or recovering used lubricant...
C208S179000, C208S180000
Reexamination Certificate
active
06191077
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method for cleaning liquid cooling lubricants, especially those with a mineral-oil base, which preferably are in continuous circulation in metal-processing facilities, in which a deposition filtration system is provided.
Above all, liquid oil-based or emulsion-based cooling lubricants are used in metal-cutting facilities which cut off chips to cool and to lubricate cutting locations and to carry off abraded particles formed as a result. The liquid cooling lubricant is in continuous circulation, and to supply several metal-processing machines, the liquid cooling lubricant is re-introduced through a central supply facility into the individual machines.
To achieve ideal cross-sectional images of the workpiece, it is necessary to clean the liquid cooling lubricant after use. For this reason, continuously operating cleaning facilities are included in the circuit in which facilities the used cooling lubricant is freed, above all, from solid abraded metal particles by means of sedimentation facilities, magnets, or filters.
Deposition filters, in which a suspension is formed from the cooling lubricant together with a filtering aid and thereafter filtered through a carrier web with deposition of the filtering aid, are used especially for the extra-fine purification of the mineral-oil-based cooling lubricant.
Such a process is known from DE 25 37 384. In this process, highly surface-active, adsorbing, solid substances are used as filtering aids. Activated earth which has an average particle size of less than 0.06 mm is particularly preferred.
Systems are also known as deposition filters which work by deposition of internally-produced contamination. However, these processes do not offer a sufficient cleaning under high performance requirements. Under normal circumstances, therefore, filtering aids are deposited in a separate circuit before the actual filtration occurs by means of the interconnected second circuit. The contaminated oil or contaminated emulsion, which has been contaminated by grits and grinds, metal filings, or other types of contamination such as rolling scale or draw-in scale, travels from the metal-cutting machines or machine tools through a dirt return line into a dirty liquid buffer container. From there, the dirty liquid is conveyed via filter pumps through cartridge filters, in the process of which the contamination accumulates on the cartridges and forms a filter cake of dirt.. The oil purified by means of the filter cartridges travels into a clean tank and is once again transported from there to the machines or to sites of use.
One disadvantage of the known methods is that large quantities of the filtering aids are necessary. Disposal of these filtering aids is extremely difficult because this involves toxic substances which have to be disposed of following special disposal techniques. In addition, the filtration intervals are of relatively short duration since the filtering aid layer very quickly becomes loaded with the absorbed contamination, so only small amounts of liquid can be filtered.
SUMMARY OF THE INVENTION
It is the object of the invention to avoid the aforementioned disadvantages and to provide a method for cleaning liquid cooling lubricants in which the use of filtering aids is reduced and the filtration intervals are lengthened.
This object is achieved by the invention as described and claimed herinafter.
The substantial advantage of the invention is that the filtering aids are introduced into to the filter circuit in the form of an inoculation which takes place continuously or discontinuously. This has the advantage that the porosity of the deposits on the filter cartridges is increased and accordingly, the exposure time, i.e. the filtration interval, can be lengthened. In addition, this system provides the possibility of very precisely metering the amount of filtering aid applied and of increasing the quality of the filtration by means of the flow resistance of the liquid through the filtering medium.
One embodiment of the invention is designed so that the inoculation occurs by means of supplying the filtering aid in the contaminated liquid feed. The inoculation can thereby be performed directly in front of the deposition filter. In this way it is possible to achieve short flow paths for the filtering aid. It is also possible to carry out the introduction of the filtering medium on the suction side of the pump for the contaminated liquid. In this way, the pressure required for introduction is reduced.
In accordance with another embodiment of the invention, the inoculation is regulated in dependance on the openness of the porosity of the filter. A further reduction in the use of filtering aids is thus attained.
Of course, in addition to inoculation, there is the possibility of carrying out a base deposition of a filtering aid. This base deposition has a significantly thinner layer thickness, however, than was necessary for the previously known deposition filters. Cellulose or a coarse corn meal, for example, are suitable for the base deposition; cellulose is suitable for the inoculation. The deposition using diatomaceous earth used previously is thus no longer necessary. Diatomaceous earth is a health hazard which necessitates very high disposal costs.
Furthermore, the advantage in using cellulose or coarse corn meal as the inoculation or deposition material is that the material used can be disposed of thermally. The disposal costs are thus reduced considerably.
These and other features of the preferred embodiments of the invention also proceed from the description and the drawings as well as from the claims, whereby the individual features can be realized individually or together in the form of sub-combinations in embodiments of the invention and in other contexts and can represent advantageous embodiments which can be protected in and of themselves, for which protection is claimed here.
REFERENCES:
patent: 3954602 (1976-05-01), Troesch et al.
patent: 4264436 (1981-04-01), Shim
patent: 4357243 (1982-11-01), Dobrez et al.
patent: 4492636 (1985-01-01), Burke
patent: 4789460 (1988-12-01), Tabler et al.
patent: 5154828 (1992-10-01), Schneider et al.
patent: 5968371 (1999-10-01), Verdegan et al.
patent: 211282 (1984-07-01), None
patent: 35 37 384 A1 (1987-04-01), None
patent: WO 98/40148 (1998-09-01), None
PCT/EP98/01451, (Filterwerk Mann and Hummel GMBH), European Search Report and International Preliminary Examination Report, Mar. 1999.
Baumgartner Reinhard
Bremer Karl-Guenther
Bungenberg Rudi
Janning Walter
Panhans Joachim
Bayerische Motoren Werke Aktiengesellschaft
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
McAvoy Ellen M.
LandOfFree
Method of cleaning liquid cooling lubricants does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of cleaning liquid cooling lubricants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of cleaning liquid cooling lubricants will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2579935