Bleaching and dyeing; fluid treatment and chemical modification – Cleaning or laundering – Dry cleaning
Patent
1997-01-24
1998-10-27
Diamond, Alan
Bleaching and dyeing; fluid treatment and chemical modification
Cleaning or laundering
Dry cleaning
8137, 81491, 68 1208, 68 1209, D06F 4308
Patent
active
058273298
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/FR95/00976 filed Jul. 20, 1995.
The invention concerns a method for cleaning in a liquid medium fabrics or clothes, and plant for implementing such method.
In cleaning techniques in a liquid medium currently used, the articles to be cleaned are first washed by bringing them into contact with the liquid, which is constantly cleaned, by agitation within a rotating drum or by spraying the liquid onto the moving articles.
In a second phase, a greater or lesser proportion of the liquid is mechanically removed by various spinning or pressing techniques.
Finally, the remainder of the liquid must be extracted from the articles during an operation known as drying.
The latter must be continued to the point of total elimination of the liquid, especially in the case of organic solvents which are often toxic, even in very small amounts.
Most cleaning machines using a solvent employ an air circulation closed circuit drying method.
The heat needed to evaporate the solvent remaining after mechanical spinning is introduced by the circulating air. The entrained solvent is then condensed in the cold part of the circuit.
The closer together the evaporation and cooling temperatures, the more similar are the heating and cooling requirements.
Modern cleaning machines are fitted with a heat pump system that recovers approximately 50% of the necessary thermal energy.
Also known in themselves are methods of cleaning clothes using solvents in which the drying step is carried out in a vacuum. This is the case in particular in the methods described in patent FR-A-1338 398 and its patent of addition FR-E-88 834. In the method as described in the patent of addition, before and/or during the application of the vacuum, application of heated vapour or heated or superheated steam, in particular vapours of solvents, to transfer the heat to the residual solvent to evaporate it is recommended. Nevertheless, this document does not contain any suggestion of applying vapour produced at a low pressure, in particular superheated steam, throughout the drying stage.
Tests conducted by the inventor of the present application have clearly shown that the use of superheated steam as soon as the vacuum is applied greatly contributes to the acceleration of the heat exchanges needed for drying.
French patent FR-2 696 480 also describes an extraction vacuum drying method, called an "azeotropic" method, using expanded steam.
This method has a certain number of advantages over the conventional methods: fast drying, complete elimination of solvent, quality of cleaning, absence of electrostatic charges.
In the current state of the art, the machines used are relatively well suited to the use of solvents such as perchlorethylene.
Nevertheless, the toxicity of this solvent is such that it is likely to be banned in the medium term if it were not possible to reduce emissions effectively to around zero, which conventional air drying machines are not really capable of.
The latter machines also represent a compromise in terms of specific treatment capacities.
In these machines, twice the "container" capacity is needed for drying as for washing. The drum capacity adopted is therefore a compromise between these two values.
Moreover, the use of hydrocarbon solvents such as undecane in conventional type machines raises safety problems that are alleviated by operating in an inert gas, produced by a relatively costly nitrogen generator.
Furthermore, because of the low volatility of the solvent, the drying time is practically doubled (compared to the chlorinated solvent).
Moreover, with the use of low volatility solvents from the hydrocarbon family, as currently envisaged, methods utilising a vacuum drying stage consume a great deal of energy, like other, more conventional methods.
The new method and the means for implementing it that are the subject matter of the present invention provide a response to the inadequacies and to the imperfections of the current technique and to the requirements expressed by users.
Accordingly, to be more precise,
REFERENCES:
patent: 1843657 (1932-02-01), Welles et al.
Diamond Alan
Fink Edward M.
I.L.S.A., S.P.A.
Michaelson Peter L.
LandOfFree
Method for cleaning in a liquid medium fabrics of clothes, and p 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 for cleaning in a liquid medium fabrics of clothes, and p, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for cleaning in a liquid medium fabrics of clothes, and p will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1610782