Technical Field

The invention relates to a chocolate tempering- machine comprising a cooling zone followed by a heating zone when seen in the flow direction of the chocolate mass, said zones including a number of separate processing sections, through which the chocolate mass passes subs antially in horizontal direction while subjected to stirring and tempering means .

Background Art

Chocolate tempering machines of the above type are known, where the stirring and tempering means are formed by stirring wings operating on horizontal cooling or heating surfaces . All the stirring wings are mounted on a vertical pivot shaft extending through both the cooling and the heating zone. Cooling and heating surfaces,, respectively, separate the processing sections from chambers through which preferably water of a predetermined temperature passes so as to cool or heat the cooling and heating sur- faces, respectively, of said processing sections.

A tempering of the chocolate mass causes formation of stable crystals in β-form in the chocolate mass in the cooling section simultaneously with formation of macro¬ crystals. It is very important to avoid formation of unstable macrocrystals because the ready-made chocolate articles can otherwise be difficult to remove from the moulds as well as be discoloured. The succeeding heating in the heating zone allows then an increase of the choco¬ late discharge temperature to between 29 and 34°C before the following moulding in the moulds. It is of vital importance for achieving a high quality of the chocolate mass that the temperature of said chocolate mass is accu-

rately controlled both during the cooling and during the heating of said mass while it passes through the temper¬ ing machine. In other words, the chocolate mass must shrink so much in connection with the hardening in the moulds that it is easily removed therefrom. Simultaneously, the chocolate article must be provided with an optimum stora- bility while maintaining especially an appetizing appear¬ ance, viz. with a glossy surface.

The known types of tempering machines do not always allow achievement in a simple manner of the above high-quality properties of all types of chocolate mass because the temperature of the chocolate mass can only be adjusted by adjusting the temperature of the cooling and heating water, respectively, as well as by regulating the number of revolutions of the shaft on which the stirring wings are mounted because the chocolate mass is heated by an inner frictional heat when it is processed by the stirring wings. It is also possible to change the temperature or the amount of chocolate mass supplied to the tempering machine. A too small amount of passing chocolate mass results easily in an overheating of the chocolate mass as well as in a melting of the formed β-crystals whereby the chocolate is easily spoilt.

Disclosure of the Invention

The object of the present invention is to provide a choco¬ late tempering machine allowing a particularly accurate control of the temperature of the chocolate mass when said mass passes the cooling zone and the succeding heating zone, and whereby a chocolate mass of a particularly high quality is produced.

The chocolate tempering machine according to the present invention is characterised in that the stirring and temper¬ ing means placed in the processing sections of the heating

zone are controllable independent of the stirring and tempering means placed in the processing sections of the cooling zone. In this manner it is possible to control the temperature of the chocolate mass in a particularly accurate manner while said mass passes the cooling zone and the succeeding heating zone. Accordingly, when the stirring and tempering means of the processing sections of the cooling zone are operated in a suitably controlϊ-ed manner, it is always possible to obtain the desired final temperature of the chocolate mass when said mass leaves the cooling zone. Independent of the processing of the chocolate mass in the cooling zone it is simultaneously possible to control the stirring and tempering means of- the processing sections of the succeeding heating zone so as to obtain the desired final temperature of the chocolate mass when said mass leaves the heating zone.

According to the invention the stirring and tempering means may comprise stirring wings mounted on vertical pivot shafts, and the pivot shaft(s) of the heating zone may be driven independent of the pivot shaft(s) of the cooling zone with the result that a particularly simple structure of the tempering machine is obtained.

Moreover according to the invention the heating zone and the cooling zone may comprise their respective separate vertical pivot shaft provided with stirring wings. As a result, it is possible to use a commonly structured temper¬ ing machine which has been adjusted to the present inven¬ tion.

In addition according to the invention the pivot shafts of the heating zone and the cooling zone may be formed by a hollow shaft and a shaft, respectively, concentrically arranged in said hollow shaft, whereby a particularly room-saving embodiment of the tempering machine is obtained because the driving means for the two shafts can be ar-

4 ranged in the same end of the tempering machine.

Moreover according to the invention the stirring and tempering means of the heating zone may comprise ultrasonic transmitters, whereby the temperature of the chocolate mass leaving the heating zone can be controlled in a particularly accurate manner.

Finally according to the invention the heating and cooling zones may be provided with temperature sensors connected to a control means, such as a microcomputer, which in turn is also connected to separate driving means for the stir¬ ring and tempering means of the heating zone and the cooling zone, respectively, so as to allow an individual control in the two zones of the temperature of the choco¬ late mass therein. As a result, it is possible in a parti- cularly accurate manner to control and regulate the temper¬ ature of the chocolate mass during the processing thereof through the tempering machine.

Brief Description of the Drawing

The invention is explained in greater detail below with reference to the accompanying drawing, in which

Fig. 1 is a partially vertical sectional view through the chocolate tempering machine according to the invention,

Fig. 2 is a top, perspective and partially sectional view through one of the processing sections of the tempering machine , and

Fig. 3 illustrates a second embodiment of a processing section.

Best Mode for Carrying Out the Invention

The chocolate tempering machine of Fig. 1 comprises cooling zone 2 and a succeeding heating zone 3 when see in the flow direction of the chocolate mass. The chocolate mass enters the tempering machine at M- _j _ and leaves said machine at M _u whereafter it is ready for hardening. The zones 2 and 3 comprise their respective number of separate processing sections 4, 5, which the chocolate mass passes in horizontal direction while subjected to stirring wings 6, 7 mounted on vertical shafts 8, 9.

All the stirring wings 6 of the cooling zone 2 are mounted on the same pivot shaft 9 which is driven by an electric driving motor Ml of a varying number of revolutions. All the stirring wings 7 of the heating zone 3 are also mounted on a separate pivot shaft 8 which is driven by another electric driving motor M2 of a varying number of revolu¬ tions . The pivot shafts 8 and 9 are arranged in continua¬ tion of one another and with a common axis of rotation 0. The entire chocolate tempering machine may be surrounded by a cover 12.

The structure of each separate processing section 4 of the cooling zone 2 is explained in greater detail below with reference to Figs . 2 and 3 , but said explanation could also refer to a processing section of the heating zone 3 because said sections are substantially identically structured.

For the sake of clarity Figs. 2 and 3 only show a partially sectional view of the bottom 18 of the processing section 4. The bottom 18 is provided with cooling channels with an inlet K-^ and an outlet K _u . The outlet K _u is preferably connected to the inlet of the next superposed processing section 4. The processing section is separated from the following processing section by means of the bottom of said following processing section. The bottom 18 is provid¬ ed with a passage 17 for the chocolate mass, and the

passage in the bottom of the following processing section Is positioned diametrically opposite said first passage. As a result, the chocolate mass is forced to move horizon¬ tally through the processing section 4 when leaving the passage 17 of the processing section in question so as to enter the passage 17 of the following processing section. While passing the processing section 4, the chocolate mass is continuously stirred by means of the stirring wings 6, said wings 6 being provided with means continuous- ly removing said chocolate mass from the bottom 18 of the processing section 4 in question as well as from the bottom of the superposed processing section. The latter means are for instance knobs 14, cf. Fig. 2, or scrapers 15, cf. Fig. 3.

In the embodiment of the processing section 4 shown in Fig. 3, the passage 17 is provided with a temperature measuring device 10 for measuring the temperature of the chocolate mass before said mass enters the processing section in question. The processing section may for inst- ance be structered as- indicated by a T in Fig. 1. The temperature measuring device 10 is connected to a microcom¬ puter 11 simultaneously connected to an inlet valve 13 for regulating the amount of cooling water fed to the bottom 18 of the processing section. In addition, the microcomputer 11 can be connected to the driving motors Ml and M2 , whereby it is rendered possible in a very accurate manner by a suitable choice of amount of supplied cooling water as well as by a suitable choice of number of revolu¬ tions of the pivot shafts 8 and 9 to control the tempera- ture of the chocolate mass while said mass passes through the tempering machine.

When the chocolate mass enters the bottom of the cooling section 2, cf. the arrow M^ in Fig. 1, it has been heated in advance to a temperature preferably in the range of 40 to 50°C. Subsequently, the chocolate mass is cooled to a

temperature substantially about 29 ^C C while passing all th processing sections 4 of the cooling zone 2. Simultaneous ly, a sufficiently high amount of crystals in stable β form is formed in the mass. Subsequently, the chocolat mass enters the succeeding heating zone 3, where it i heated to a temperature substantially in the range of 3 to 35°C while being processed in the processing section 5 of said heating zone 3. As a result, the unstable cryst als formed in the chocolate mass are melted, and nothin but stable crystals remain in microform in the chocolat mass, whereafter said mass leaves the heating zone 3 an continues to a hardening process, optionally in a chocolat moulding machine .

As the stirring wings 6 of the cooling zone 2 can b controlled completely independent of the stirring wings of the heating zone 3, it is possible in combination wit the temperature of the cooling water always to achiev the correct, predetermined temperature of the chocolat mass everywhere in the tempering machine 1. A suitabl choice of number of revolutions of the pivot shaft 8 o the heating zone 3 allows feeding of a varying inner energ in form of the inner frictional heat to the chocolat mass, said frictional heat resulting from the processin of the chocolate mass by the stirring wings 7 in th heating zone 3.

Other embodiments are also possible, where the stirrin wings of the heating zone 3 have been completely or parti ally replaced by ultrasonic transmitters also feeding a amount of inner energy to the chocolate mass.

Many modifications may be carried out without thereb deviating from the scope of the invention. Thus the pivo shafts of the cooling zone and the heating zone may b replaced by a hollow shaft and a shaft arranged concentric¬ ally in said hollow shaft in such a manner that the stir-

ring wings of the two zones can be driven from the same end of the tempering machine.