The invention relates to a method of removing labels from the exterior of reusable bottles of glass by using a cleaning agent-NaHC03-which is directed towards the bottles with pressurized air. This is done before the bottles continue into the washing machine for the inside cleaning.

The invention can be used with mayor advantage in the industrial washing plants and by the beverage industries having their own washing machine.

At the time when the recycling system for glass bottles, e. g. for beer and soft drink bottles as well as wine bottles, was introduced, nobody thought of the drinking water supplies. To-day, however, the scarcity of pure drinking water is a global problem, and the attempts made to reduce the water consumption by means of high water rates has made water the heaviest cost for the industry in question. To that can be added the treatment of the waste water.

The known process of bottle cleaning consists in cleaning the bottles inside and outside by immersion in a huge vat with heated water to which is added caustic soda. However, in order to remove the glue and thus the labels, especially from wine bottles, a strong chemical additive is used. With this method there are still bottles with rests of glue and label because new types of self-adhesive labels are developed and they are difficult to remove. The result is that too many bottles will have to pass through the washing machine 3 to 4 even 5 times and even so they are not clean. Such bottles are sent to be crushed.

A method for cleaning surfaces, including labels especially of plastic, is known.

(DE 197 09 621 A). The cleaning agent, dry ice, is a totally different agent and useless for the purpose we describe. There is another method known to cut and remove tubular plastic labels from bottles. (EP 0 587 358 A 1). This method is also useless for the purpose we describe, and furthermore, like the patent first mentioned, water is used to remove the cut labels. We use only air together with NaHC03.

Another method for cleaning the surface layer of the inside of a container, such as a drum by using NaHC03 is known. (US 6.113. 475). The NaHC03 particles used are, however, so fine that it is described as powder and this is blasted by pressurized air through a complicated apparatus on to the inside of a container together with water. For our purpose NaHC03 as fine as powder will be of no use. A bigger particle, usually between 0,7 and 1 mm, is demanded, i. e. should be described as a granulate. And we do not use water, it is not necessary for our purpose. The construction of the apparatus is unfit for our purpose which is the cleaning of the exterior of glass bottles in a sequence where the existing method. of production have other claims to the apparatus than what is described for the cleaning of the inside of larger containers such as drums. Further, there is also a known method (DE 4.018. 113) relating to an apparatus for the removal of foil and labels from containers, e. g. bottles. There is, however, no mention of any particular cutting agent, but water is suggested. Water alone is useless for our purpose as it can not dissolve the glue and by that the label. As to the construc- tion of the apparatus, we have the same comments as stated above.

(see US 6. 113. 475). Finally, there is a known method (US 5.885. 401) which re- lates to the removal of tubular labels by first cutting a parting line through the label so it can be removed. There is no mention of a particular cutting agent, but the propelling agent could be either water or air and water. The purpose of our invention is 1) to carry out the exterior cleaning of glass bottles, especially wine bottles, without using water, 2) to apply a natural cleaning agent NaHC03 as a granulate. US no. 5.885. 401 does not meet this demand.

In the comext of our invention a solution has been developed for the removing of"difficult"labels, especially from wine bottles, comprising: a) a cleaning agent NaHC03, which as a granulate is injected into an air stream which is directed towards the surface of the bottle, b) that there is a relative movement between the bottle and the air stream, c) that the blasting is carried out under the right pressure, angle and speed, so that the label is removed when the granules reach the bottle, and

a machine has been designed (a cleaning station) comprising: a) a blasting chambers with one or several nozzles, b) a top holding device and bottom support for fastening the bottle in the blasting chamber, c) a drive in the top holder for the rotation of the bottle during the blasting.

The machine is designed for installation on the conveyor belt and placed between the starting point where the unwashed bottles are placed onto the conveyor belt and the known type of washing machine.

Fig. 1 shows a conveyor belt (1), the cleaning station (2) and the conveyor belt leading to the washing machine (3) for washing the inside of the bottle.

Fig. 2 shows the blasting chamber (4), nozzles (5) and bottles seen from above (6). Fig. 3 shows a drive for the rotation of the bottle (7), bottle top (8), bottom support (9), the body of the bottle (10), label (11) and nozzles (5). The cleaning station (2) comprises one, two or more blasting chambers, each of which having one or several nozzles each connected to a NaHC03 blasting machine. Each blasting chamber should be connected to a vacuum conduit for the removal of pieces of label and residua of glue and cleaning agent into a separate bin.

The traditional method known for wine bottles places the unwashed bottles by hand and in an upright position onto the conveyor belt (1). The pressure from the bottles coming after, pushes these into the blasting chamber (4) where they are held by a bottom support (9) fixing the bottle at the bottom and at the same time the bottle top (8) will be supported with a rubber cone (7) which is pressed into the bottle neck acting as a counterhold centering device, and drive. The nozzles (5) direct the pressurized air stream to the body of the bottle (10) in the correct angle. When the label (11) has been removed, i. e. after a few seconds, the bottom support and top holder are withdrawn and the pressure from the in- coming bottles push the blown bottles further on the conveyor belt and into the washing machine for the inside cleaning in the cleaning vat, and the water now only containing caustic soda.

The cleaning agent used is a natural product in a larger crystal size of blasting

grade Sodium Bicarbonate. Being a product used in the food industry (however in a smaller size, as powder) it is approved and need not to be classified under the Regulation of the Factories Inspectorate. The water solubility is 100, %.

Tests related to the invention have been made by blowing manually on used and unwashed wine bottles as they are received from the bottle collectors. Also we have carried out cleaning of wine bottles still with glue and paper residua after being through a washing machine up to 4 times. Both tests confirmed the idea of the invention and gave the expected result. Thus the cleaning method related to the invention solve the problem with"difficult"labels, i. e. labels which can not be removed completely in the traditional way in the washing machine. All the bottles can be cleaned completely on the outside without damaging the surface, and the designed machine express the utility of the method for industrial purpose in connection with the known washing machines. The washing industries will be able to reduce the water consumption considerably due to the fact that the water contained in the huge vat will be without glue and paper residua, which again means fewer re-fillings of the vat with clean water and less water is needed when all the bottles only will have to pass through the washing machine once.

Finally, the chemicals applied at present can be omitted completely. All of this will result in a purer discharge of waste water from the washing plants.