Such a device is known and is much used in catering establishments, such as for instance so-called fast-food restaurants, for preparing soft ice-cream, milk shakes and similar products. For this purpose a mixture of the soft ice-cream constituents is carried in the form of a liquid paste into the first space where cooling of the mixture normally takes place. It is noted that the terms"mixture of soft ice-cream constituents"and"soft ice-cream constituent mixture"are understood to include mixtures of milk shake constituents and similar products. In the second space a further cooling of the mixture takes place, preferably to below 0°C. The further cooled mixture can subsequently be drawn off per portion from the second space as soft ice-cream or as a milk shake or similar product. For this purpose the second space is coupled to at least one draw-off member. Owing to the coupling of the first space to the second the soft ice-cream constituent mixture can flow from the first to the second space in a manner which may or may not be forced; this can take place for instance after a quantity of soft ice-cream has been drawn off from the second space, so that the second space is completely filled at all times. Air is moreover added to the mixture during the passage of the soft ice-cream constituent mixture from the first to the second space.

Since a soft ice-cream constituent mixture is composed substantially of dairy products and sugar, such a mixture is sensitive to bacteria. This sensitivity is such

that strict hygienic measures must be observed to limit the growth of bacteria as much as possible. Particularly locations on or close to the outlet where the soft ice- cream or related product is drawn off are found to be sensitive to bacteria. Situated at this outlet is the transition between the cooled device which is not accessible from outside and a non-cooled area which is accessible from outside. During dispensing of soft ice-cream or a related product remnants of the product are normally left on or close to the outlet of the draw-off member which is in open communication with the non-cooled environment. It will be apparent that bacteria growth in the discarded remnants will be stimulated rather than inhibited, not least because the sweet product attracts insects.

In order to inhibit as far as possible the above stated undesired bacteria growth the draw-off member must be cleaned and made sterile with great regularity. This usually takes place by wiping clean the outlet of the draw-off member with a cloth or brush soaked with a solution of a cleaning agent or disinfectant. It is important that this latter operation is carried out very carefully so that no product remnants whatever remain behind on the underside. If the care taken is not optimal and product remnants do thus remain behind on the outlet, this will result in further bacteria growth and deterioration of the product to be dispensed.

It will be apparent that the above mentioned method of cleaning the draw-off member is not"watertight"and that the risk of the operation not being carried out carefully is considerable.

The present invention has for its object to provide a device for preparing soft ice- cream, milk shakes and related products, wherein the above stated problems do not occur. For this purpose the present invention provides a device as according to the preamble which is characterized in that the draw-off member is provided with heating means which can bring about a local heating of the draw-off member to at least 70°C.

Through local heating of the draw-off member, wherein at least a temperature of 70°C must be reached, the possibly present bacteria located in the soft-ice cream product remnants on the draw-off member are eliminated.

It should be noted that in some embodiments of soft-ice cream devices the draw-off member is already subjected to a heat treatment. These are devices which are embodied such that they can be subjected to a process wherein the soft ice-cream constituent mixtures situated in both the first space and in the second space are heated simultaneously to about 70°C, subsequently held at this temperature for about 30 minutes and then cooled. This process is known as pasteurization and re- cooling. This process is normally carried out at the end of each working day in order to rid the soft ice-cream constituent mixture present in the device as far as possible of the bacteria which may be present therein. A part of the draw-off member is also heated by the heat transfer from the mass in the second space.

The heat to which the draw-off member is subjected during the above pasteurization process is however insufficient to achieve complete elimination of the bacteria present in or on the draw-off member. Furthermore, a part of the draw- off member on or close to the outlet is usually manufactured from plastic and in this part the temperature at which elimination of the bacteria occurs is not reached.

It will be apparent that the present invention does not relate to the heating means which realize a pasteurization treatment but to separate heating means which on the contrary are incorporated in the draw-off member and can bring about a heating at that location.

In a particular embodiment the heating means comprise an electrical heating element.

Such an element can be controlled from outside and can preferably be adjusted, for instance such that heating of at least a part of the draw-off member takes place during pasteurization of the first and the second space.

Since the problem of the undesired bacteria growth takes place particularly in the part of the draw-off member close to the outlet, it is recommended that the heating means are provided on or close to the outlet of the draw-off member.

In a preferred embodiment the heating means can be releasably coupled to the outlet of the draw-off member.

In this embodiment a simple coupling of the heating means to the outlet takes place, followed by performing of a heating treatment, whereafter the heating means are removed and the outlet is free of bacteria.

Finally, the present invention relates to heating means suitable for use in the above stated device.

In an embodiment suitable for this purpose, such heating means can likewise be applied in already existing devices for preparing soft ice-cream, milk shakes and related products in order that these devices are also provided with a"watertight" system for the removal of undesired bacteria.

The present invention will be further elucidated hereinbelow with reference to the annexed drawing, in which: figure 1 shows schematically a draw-off member of a device for preparing soft ice-cream or related products, in addition to a part of this device; and figure 2 shows schematically the draw-off member of figure 1 which is releasably coupled to heating means.

The figure is purely schematic and not drawn to scale. For the sake of clarity some dimensions in particular are shown in greatly exaggerated manner. Corresponding components are designated as far as possible in the figures with the same reference numeral.

Figure 1 shows schematically the part of a device for preparing soft ice-cream, milk shakes and related products 1 where the draw-off member 2 is provided.

Reference numeral 3 shows the second space of the above stated device, or the freezing cylinder, where the soft ice-cream constituent mixture is cooled to below 0°C. This space 3 communicates with draw-off member 2 via a passage 4. Draw- off member 2 comprises a housing 5 of substantially circular cross-section. As the figure shows, a part of the housing also forms the front side of the second space 3 of the soft ice-cream device. In housing 5 is arranged a substantially solid, cylindrical element 7 which in the configuration shown in the figure connects to the inner wall of housing 5 by means of two 0-rings 8,9. Reference numeral 10 shows the outlet of draw-off member 2.

The housing 5 of draw-off member 2 is usually manufactured from plastic material, as is the upper part 7A of cylindrical element 7. The lower part of this latter element is usually manufactured from a metal.

When a portion of soft ice-cream is drawn off from the device 1, the cylindrical element 7 is moved in upward direction using operating means (not shown in the figure); this situation is indicated with dashed lines in figure 1. During this situation the soft ice-cream product present in freezing cylinder 3 can flow out of the outlet 10 via passage 4. Typically situated on the outlet is a nozzle (not shown in the figure) which is connected fixedly or releasably, for instance by means of a screw connection, to the outlet 10 of draw-off member 2. When cylindrical element 7 is moved downward again into the position indicated in figure 1 with full lines, the connection of passage 4 to outlet 10 is blocked so that the soft ice-cream product cannot flow out of the outlet.

Due to the reciprocating movement of cylindrical element 7 which comes into contact with the soft ice-cream product, ice-cream remnants remain behind particularly on the underside of the housing 5 close to outlet 10 and in the part close to O-rings 8,9. As stated, such product remnants are very sensitive to bacteria.

When the soft ice-cream device is embodied such that the soft ice-cream constituent mixture in the first and second space can be subjected to a pasteurization process, heat is transferred during this process from the mass in the second space to the draw-off member. A part of the draw-off member, i. e. the part manufactured from metal, is herein found to be heated to a temperature of 70°C.

However, the parts of draw-off member 2 which are manufactured from plastic, i. e. housing 5 and a part of cylindrical element 7, where as discussed above a source of bacteria growth is present, are found not to reach such a temperature, so that here the danger of excessive bacteria growth is not eliminated.

This problem is solved according to the present invention by providing the draw- off member with heating means which can bring about a local heating of the draw- off member to at least 70°C. Such heating means can for instance comprise an electrical heating element which is incorporated in the housing 5 of draw-off member 2 and can effect a local heating to at least 70°C of those parts of the draw- off member where there is a danger of excessive bacteria growth.

A preferred embodiment of the device according to the present invention is shown in figure 2. This figure shows a device as according to figure 1, which however is releasably coupled to heating means 12 in the form of an electrical heating element which can be coupled to the outlet of draw-off member 2 and can effect a local heating of the parts of the draw-off member where there is a danger of excessive bacteria growth. Setting the heating means into operation results in the plastic parts of the draw-off member also being heated to 70°C so that bacteria growth is eliminated. The coupling between heating means 12 and outlet 10 can take place in any manner known to the skilled person.