DESCRIPTION

The invention regards a mixer with rotatable bowl, as well as a method for using such mixer with rotatable bowl.

Mixing machines for making bread, pasta and the like, also referred to as 'mixers', generally comprise a framework for supporting a bowl for containing a dough to be mixed and at least one mixing tool, driven to operate in the containment compartment of the bowl.

In order to improve the quality of the dough mixers with fixed bowl are currently known, in which such fixed bowl comprises an inner container at least partly surrounded by a jacket defining - with said inner container - an interspace for a cooling fluid, treated by a corresponding cooling circuit outside the bowl and directly connected to the aforementioned interspace.

Thus, the mixer is capable of processing the dough, keeping it at the ideal temperature for the development of gluten and below the rising limit.

However, these mixers reveal the drawback of the fixed bowl, where a rotatable bowl determines major advantages of different type, for example in terms of production speed, optimisation of the distribution of the dough in the bowl, and the like.

In mixers with rotatable bowl of the prior art, a generic rotatable bowl, in a normal operating configuration, generally rotates around a vertical axis.

In order to overcome the drawbacks of the mixers of the prior art, there have been provided, and they are also currently known, mixers with rotatable bowl whose interspace for a cooling fluid is interconnected with a cooling circuit. A similar mixer is for example described in the European patent EP1 1 17300. Thus, the rotatable bowl is configured to rotate around a vertical axis during the operation of the at least one mixing tool arranged therein.

Such rotatable bowl is configured to rotate, in the use configuration thereof, around a vertical axis, where such rotation must be considered as a rotation by angles greater than 360°, i.e. a continuous rotation for a pre-established period of time in the same rotation direction.

The vertical axis X coincides with the symmetry axis of the rotatable bowl when the latter is in use configuration.

The rotation of the rotatable bowl, as mentioned above, may occur simultaneously with the operation of the mixing tool; thus, besides the mixing of a dough determined by the tool, there also occurs a mixing of the same dough determined by the rotation of the bowl in which the dough is arranged; the rotation of the bowl facilitates the continuous re-distribution of the dough in the bowl.

Such mixer with rotatable bowl has a stable connection between the cooling circuit and the interspace of the bowl, obtained in a particularly complex manner, with a hydraulic connection defined at the rotation axis of the bowl and comprising an axial sealing joint which is severely stressed by the rotary movement of the bowl.

Though efficient, such mixer is complex and expensive to manufacture, both in terms of components and in terms of assembly and thus manpower.

Furthermore, the stability of the hydraulic connection makes the sealing members more exposed to wear, with ensuing risks of malfunctioning and costs-related machine shut down to replace components.

The task of the present invention is to provide a mixer with rotatable bowl capable of overcoming the aforementioned drawbacks and limits of the prior art.

In particular, an object of the invention is to provide a mixer with rotatable bowl whose bowl can be cooled in a simple and reliable manner.

Another object of the invention is to provide a mixer with rotatable bowl whose connection and hydraulic sealing elements are subjected to little or no wear.

A further object of the invention is to provide a mixer with rotatable bowl that is more robust and less subjected to machine shut downs with respect to the similar mixers of the known type.

Still another object of the invention is to provide a mixer with rotatable bowl with performance and efficiency not below the mixers of the known type.

A further object of the invention is to provide a method for using a mixer with rotatable bowl as the main task.

The aforementioned task and objects are obtained by a mixer with rotatable bowl according to claim 1 .

Further characteristics of the mixer with rotatable bowl according to claim 1 are described in the dependent claims.

The aforementioned task and objects, alongside the advantages described hereinafter, shall be outlined in the description of an embodiment of the invention, provided solely by way of non-limiting example, with reference to the attached drawings wherein:

- figure 1 represents a perspective view of a mixer with rotatable bowl according to the invention;

- figure 2 represents a perspective cross-section of a rotatable bowl according to the invention;

- figure 3 represents a first perspective view of a component of the rotatable bowl according to the invention;

- figure 4 represents a second perspective view of the component of figure 3; - figure 5 represents a portion of a first diametrical section of the rotatable bowl of a mixer according to the invention;

- figure 6 represents a portion of a second diametrical section of the rotatable bowl;

- figure 7 represents a perspective cross-section of the reversible connection means of a mixer according to the invention in a first operating configuration;

- figure 8 represents the same view of figure 7 in a second operating configuration;

- figure 9 represents a sectional lateral view of a first part of the reversible connection means;

- figure 10 represents a sectional lateral view of a second part of the reversible connection means;

- figure 1 1 represents a further perspective view of the connection means;

- figure 12 schematically represents a cooling circuit of the mixer according to the invention;

- figure 13 schematically represents a method of use of a mixer with rotatable bowl according to the invention;

- figure 14 represents a lateral view of a detail of the mixer according to the invention.

With reference to the aforementioned figures, a mixer with rotatable bowl according to the invention is indicated in its entirety with number 10.

Such mixer 10 comprises a framework 11 for supporting a driven rotatable bowl 12, for containing a dough, inside which there is driven to operate at least one driven mixing tool (not shown in the figures and to be deemed of the per se known type), such as - for example but not exclusively - a shaped blade, or a spatula, or a plurality of blades or a plurality of spatulas.

As clearly visible in figure 2, the rotatable bowl 12 comprises an inner container 13 laterally surrounded by means for the thermal treatment of the inner container 13.

Such means for the thermal treatment of the inner container 13 are of the thermal exchange fluid type.

In the embodiment of the invention described herein, to be deemed a non- limiting example of the invention, such means for the thermal treatment of the inner container 13 consist of means for cooling the inner container 13.

The thermal exchange fluid is a cooling fluid, for example glycol.

The thermal treatment means, hereinafter described for cooling during the mixing operations, shall be deemed similarly usable as thermal treatment means which are heating means, with the aim of heating during the mixing operations; similarly, the thermal treatment means shall be deemed as usable for pasteurisation operations, or, still, for maintaining a desired temperature. The distinctiveness of the invention lies in the fact that said thermal treatment means comprise reversible connection means 17, for filling the thermal treatment means with a thermal exchange fluid, such reversible connection means 17 being configured to alternatingly take a configuration selected from among

- a connection configuration, with the rotatable bowl 12 inoperative, for introducing and circulating the thermal exchange fluid in said thermal treatment means of the inner container 13,

- a disconnection configuration, with the rotatable bowl 12 available for the rotation, and with the at least one driven mixing tool driven to operate in the rotatable bowl 12.

Thus, the rotatable bowl 12 is configured to rotate during the operation of the at least one mixing tool arranged therein.

Such rotatable bowl 12 is configured to rotate, in use configuration, around a vertical axis X, clearly visible in figure 1 .

The rotatable bowl 12 is suitable to rotate with respect to the vertical axis X by angles greater than 360°, in particular it is suitable to perform several complete sequential rotations, i.e. rotating continuously for a pre-established time interval in the same rotation direction.

The vertical axis X coincides with the symmetry axis of the rotatable bowl 12 when the latter is in use configuration.

In particular, in the embodiment of the mixer according to the invention, herein described by way of non-limiting example of the invention, the thermal treatment means with thermal exchange fluid comprise a jacket 14 laterally surrounding said inner container 13 to define - with the inner container 13 - an interspace 15 for the thermal exchange fluid.

The reversible connection means 17 determine the connection of the thermal treatment means with a circuit 16 for treating and circulating said thermal exchange fluid.

The rotatable bowl 12 has an outer insulating protection lining 18.

Such outer lining 18 comprises an outer wall 19 defining - with the jacket 14 - a second interspace 19a designated to contain a thermally insulating material.

The jacket 14 comprises a lower corner portion 14a extending to surround a peripheral portion of the bottom of the inner container 13.

From the wall 19 there extends an annular lining 19b suitable to cover part of the bottom of the bowl 12, and in particular to cover the lower corner portion

14a.

Such outer lining 18 counters the thermal exchange of the fluid, inside the jacket 14, with the outside, so as to prevent the external temperature from affecting the thermal exchange fluid, the latter maintaining the ideal operating temperature as long as possible.

The rotatable bowl 12 comprises an inlet mouth 20 and an outlet mouth 21 for the interspace 15.

Such inlet 20 and outlet 21 mouths are defined on a block 22 fixed to the rotatable bowl 12.

The reversible connection means 17, herein described by way of non-limiting example of the invention, comprise, for each of said inlet 20 and outlet 21 mouths, an automatic quick coupling 23 and 24 respectively.

Such automatic quick couplings 23 and 24 are driven to operate in a radial direction or in a direction parallel to a radial direction with respect to the rotation axis X of the rotatable bowl 12.

The automatic quick coupling 23 and 24 is, for example, of the male-female type, whose first part 25 and 26 is carried by the block 22, while a second corresponding part 27 and 28 is fixed to a moveable support plate 29.

By way of example, each first part 25 and 26 consists of a female element of the corresponding automatic quick coupling 23 and 24, while each second part 27 and 28 consists of a male element of the corresponding automatic quick coupling 23 and 24.

Each first part 25 and 26 is connected to a line, either delivery or return, of the circuit 16 for the thermal exchange fluid of the rotatable bowl 12.

Such automatic quick couplings 23 and 24 can be of the per se known type, for example of the concentric double-coupling type.

An automatic quick coupling 23 and 24 with concentric double-coupling provides for, for example, an outer collar 30 extending from the body 31 of a second part, for example the second part 27 as exemplified in figure 9, suitable to be inserted into a counter-shaped opening 32, with sealing ring 33, of the body 34 of the first corresponding part 25, for pushing to recede a shutter bushing 35 inside the body 34 of the first part 25, so as to determine a first coupling defining a sealing duct for the passage of the fluid; an axial stem 36, visible in figure 10, present in the first part 25, and integrally joined to the body 34 thereof, is revealed by the receding motion of the shutter bushing 35, such axial stem 36 being designated to abut against a juxtaposed axial shutter 37 extending in the body 31 of the second part 27 and free to recede axially therein, so as to determine a second coupling suitable to open the communication between the two first 25 and second 27 parts.

Such automatic quick couplings 23 and 24 advantageously have annular seals, i.e. O-rings, made of silicone so as to resist against the chemical attack by the thermal exchange fluid.

The reversible connection means 17 also comprise actuator means for displacing said moveable support plate 29.

Such actuator means for example consist of a pneumatic cylinder 40, secured for a fixed part thereof to the framework 11 and for a moveable part thereof to the support plate 29.

The pneumatic cylinder 40 comprises a casing 41 and a stem 42, with piston. The casing 41 defines the fixed part of the pneumatic cylinder 40 and it is fixed to the framework, while the stem 42 defines the moveable part and carries the support plate 29, for example by means of an intermediate flange 44.

The casing 41 is fixed to the framework 11 through a bracket 45, clearly visible in figure 1 1 .

In said interspace 15 between the inner container 13 and the jacket 14 there is defined a labyrinth circuit 50, whose inlet and outlet correspond to said inlet mouth 20 and outlet mouth 21 of the interspace 15, and it is configured to conduct the thermal exchange fluid over the entire available outer surface of the inner container 13.

The inlet 20 and outlet 21 mouths are approached to each other, so as to enable the simultaneous coupling of the automatic quick couplings 23 and 24 as described above.

In the present embodiment, the labyrinth circuit 50 defined in the interspace 15 comprises two coil-like channels, respectively 51 and 52, clearly visible in figures 3 and 4, communicating with each other, each of which extending to involve a semi-cylindrical portion of said interspace 15.

Such coil-like channels 51 and 52 are defined by several coaxial annular partitions 54 where the reference axis is the rotation axis of the rotatable bowl 12, extending over the entire radial width of the interspace 15, defining several superimposed annular channels 55 surrounding the inner container 13.

A lower annular channel 55a of such annular channels 55 is involved by the inlet 20 and outlet 21 mouths.

Such annular channels 55 are shut off by two opposite vertical septa 56 and 57, a first septum 56 being arranged between said inlet 20 and outlet 21 mouths, and a second septum 57 being arranged in a diametrically opposite position.

The first septum 56 is shaped so as to shut off all annular channels 55.

The second septum 57 is shaped so that an upper annular channel 55b is vacant, i.e. it is not shut off by such second septum 57.

The annular partitions 54 have two passage openings, for example indicated with 58, 59, 60 and 61 in figures 3 and 4, one on one side and the other on the other side with respect to one of the two vertical septa 56 and 57 and in proximity of a corresponding vertical septum.

The two openings 58 and 59 of an annular partition 54, for example a first annular partition 54a in figure 3, are arranged at a first vertical septum, for example the front vertical septum 56, while the two openings 60 and 61 of a previous or subsequent annular partition, for example the annular partition 54b in figure 4, are arranged at the opposite vertical septum, for example the rear vertical septum 57.

The annular partitions 54 and the vertical septa 56 and 57 determine the two coil-like channels 51 and 52 which are placed in mutual communication by means of the upper annular channel 55b.

The upper annular partition 54c is continuous and closes the interspace 15 at the top part.

In a variant embodiment of the invention, not illustrated for the sake of simplicity, the thermal treatment means with thermal exchange fluid consist of a tubular coil, for example made of metal material, copper in particular, reel-wound around the inner container of the rotatable bowl.

The reversible connection means 17 also comprise centring means for the proper connection of said automatic quick couplings 23 and 24.

For example, such centring means comprise at least one centring relief 62, for example a pin, with a frusto-conical or rounded or wedge-shaped end 63 extending from the support plate 29 to which it is fixed, suitable for insertion into a counter-shaped centring seat 64 fixed to the rotatable bowl 12, for example defined in the block 22.

In the embodiment described herein, there are present two centring reliefs 62 and 65, and two corresponding centring seats 64 and 66.

Each centring relief 62 and 65 extends from the support plate 29 covering a greater length with respect to the extent of projection on the same side of the support plate 29 of the second parts 27 and 28 of the automatic quick couplings 23 and 24 towards the block 22 carrying the first parts 25 and 26; thus, the centring reliefs 62 and 65 shut off the inlet blocks of the respective centring seats 64 and 66 before the second parts 27 and 28 start coupling with the first parts 25 and 26, thus ensuring the correct alignment of the automatic quick couplings 23 and 24 before the connection translation starts.

The mixer 10 according to the invention also comprises a system for directing the rotatable bowl 12 for a first alignment of the first parts 25 and 26 with the respective second parts 27 and 28 of the automatic quick couplings 23 and 24. Such direction system comprises a detection sensor 68, for example an inductive sensor, fixed to the framework 11 , positioned and configured to detect a position marker, for example a sign, or a relief 22a like in figures 1 and 3, defined on the rotatable bowl 12.

The detection sensor 68 is schematised in figure 14; such detection sensor is fixed to a support bracket in turn positioned on the framework 11 in an available area established when assembling the mixer 10. Once through with the processing cycle, or for other reasons, the rotatable bowl 12 must stop; then there intervenes an alignment operative mode, or step, by means of which the rotatable bowl 12 is made to rotate once at a suitable speed, lower than the processing speed; during the aforementioned rotation the sensor detects the marker and the immediate stop of the bowl 12 is actuated.

Given that the masses in question make the alignment position inaccurate, there are allowed millimetric deviations which are then resolved through the centring means, whose pins with frusto-conical ends 63 force the alignment. The circuit 16 for treating and circulating said cooling fluid is incorporated in the framework 11.

Alternatively, the circuit 16 is outside the mixer 10 and it is connected to the mixer 10 through reversible connection means 17.

Such circuit 16, in the present embodiment, consists of a cooling circuit, and it is designated for cooling the cooling fluid.

Such cooling circuit 16 comprises a tank for accumulating the cooling fluid, suitable to contain such cooling fluid at amounts proportional to the size of the rotatable bowl 12, given that the larger the bowl, the greater the amount of cooling fluid required to obtain the desired cooling.

In particular, the cooling circuit comprises, as schematised in figure 12:

- a duct 16a for delivering the cooling fluid coming from a chiller unit 70, per se known, and directed towards the bowl 12,

- a duct 16b for the return of the cooling fluid, from the bowl 12 towards the chiller unit 70,

- a by-pass unit 16c configured to enable the circulation of the cooling fluid in the cooling circuit 16 when the reversible connection means 17 are in disconnection configuration, with the rotatable bowl 12 free to rotate and thus to operate,

- a first thermometer 16d for detecting the temperature in the delivery duct

16a,

- a second thermometer 16e for detecting the temperature in the return duct

16b,

- a first manometer 16f for detecting the pressure in the delivery duct 16a,

- a second manometer 16g for detecting the pressure in the return duct 16b, - a delivery pressure relief valve 16h, - a discharge 16m for the pressure relief valve 16h,

- a delivery pipe 16p connecting the delivery duct 16a with the reversible connection means 17,

- a return pipe 16q connecting the reversible connection means 17 with the return duct 16b.

The by-pass unit 16c comprises a first three-way valve 16r, arranged on the delivery duct 16a, a second three-way valve 16t, arranged on the return duct 16b, and an intermediate tubular element 16z, hydraulically connecting the first three-way valve 16r and the second three-way valve 16t.

The first 16r and second 16t three-way valves are, for example, of the pneumatic control type.

On a compressed air line by means of which the three-way valves 16r and 16t are controlled, there is installed a flow regulator, i.e. a pressure regulator filter, so as to be able to control the switching speed of the three-way valves; in particular, such three-way valves are controlled so that the second valve 16t on the return duct 16b closes and opens respectively delayed and in advance with respect to the first valve 16r on the delivery duct 16a, so as to avoid creating overpressure in the interspace 15 of the bowl 12.

The reversible connection means 17 also comprise means for checking whether connection or disconnection has occurred.

Such checking means comprise, for example, a pair of sensors fixed in cavities present on the casing of the pneumatic cylinder 40 and provided as accessories thereof.

Such control means also comprise an inductive sensor 69, visible in figure 14, integrally joined with the framework 11 , which detects successful and proper recession of the support plate 29; such inductive sensor 69 represents a redundant control, required considering potential damage to the bowl 12 which could arise from failure or malfunctioning of the sensors associated to the pneumatic cylinder 40.

A method for using a mixer with rotatable bowl 10 as described above is also part of the invention.

Such method, schematically illustrated in figure 13 and therein indicated in its entirety with number 80, comprises, in the order below, as outlined in the chart of figure 13, the following operative steps:

- starting a thermal treatment cycle, for example a cooling cycle, for the rotatable bowl 12; such step is indicated with block 81 ;

- directing the rotatable bowl 12; such step is indicated with block 82;

- connecting the rotatable bowl 12 to the circuit 16, for example a cooling circuit; such step is indicated with block 83;

- recirculating the thermal exchange fluid, for example a cooling fluid, and thermally treating, i.e. cooling, the rotatable bowl 12; such step is indicated with block 84;

- loading the rotatable bowl 12 with a dough; such step is indicated with block 85;

- disconnecting the rotatable bowl 12 from the circuit 16; such step is indicated with block 86;

- starting a cycle for mixing the dough loaded in the rotatable bowl 12; such step is indicated with block 87.

In this method, the cycle for mixing the dough loaded in the rotatable bowl 12 comprises the rotation of the rotatable bowl 12 around the rotation axis X thereof.

Such method also comprises the following operative steps:

- checking whether a supplementary thermal treatment, for example supplementary cooling, of the rotatable bowl 12 is required; such step is indicated with block 88;

- if supplementary thermal treatment is not required, then complete the mixing cycle and remove the mixed dough; such step is indicated with blocks 89 and 90;

- if supplementary thermal treatment is required, then follow the subsequent auxiliary operations:

- directing the rotatable bowl 12; such step is indicated with block 91 ; such direction step, around the axis X, is actually required for the rotation of the rotatable bowl 12 around the vertical axis X during the execution of the mixing cycle 87;

- connecting the rotatable bowl 12 to the circuit 16; such step is indicated with block 92;

- recirculating the thermal exchange fluid and thermally treating the rotatable bowl 12; such step is indicated with block 93;

- disconnecting the rotatable bowl 12 from the circuit 16; such step is indicated with block 94; - starting another cycle for mixing the dough loaded in the rotatable bowl 12; such step is indicated with the same block 87 indicated above.

The method 80 according to the invention comprises, subsequently to the step 90 of removing the dough, the following operative steps:

- checking whether to load new dough; such step is indicated with block 95;

- if new dough is not to be loaded, then stop using the mixer 10; such step is indicated with block 96;

- if new dough is to be loaded, then start a cycle for the thermal treatment of the rotatable bowl 12 as shown in block 81.

Thus, the loading of the dough to be processed can be carried out with the bowl connected keeping the glycol recirculating in the interspace 15, or

- alternatively - the dough can be loaded with the rotatable bowl disconnected. Though the mixer 10 and the method 80 according to the invention are described above with thermal treatment means which are cooling means and for cooling during the mixing operations, they shall be deemed similarly usable with thermal treatment means which are heating means and for heating during the mixing operations; similarly, the thermal treatment means shall be deemed as usable for pasteurisation operations, or, still, for maintaining a desired temperature. Basically, it has been observed that the invention attains the pre-set task and objects.

In particular, the invention provides a mixer with rotatable bowl whose bowl can be treated thermally, for example it can be cooled, in a simple and reliable manner, thanks to reversible means for the connection of the means for the thermal treatment, for example cooling means, of the bowl with a circuit for the treatment of the thermal exchange fluid, configured to operate in a connection and disconnection configuration by means of simple and precise translation motions.

In particular, the invention provides a mixer with rotatable bowl whose connection and hydraulic sealing elements are subjected to little or no wear, given that when the reversible connection means are in connection configuration, the sealings operate statically.

Furthermore, the invention provides a mixer with rotatable bowl that is more robust and less subjected to machine shut downs with respect to the similar mixers of the known type.

The invention provides a mixer with rotatable bowl with performance and efficiency not below the mixers of the known type.

In addition, the invention provides a method for using a mixer with rotatable bowl as per the main task.

The invention thus conceived is susceptible to numerous modifications and variants, all falling within the inventive concept; furthermore, all details can be replaced by other technically equivalent elements.

Basically, the components and materials used, provided they are compatible with the specific use, as well as the dimensions and contingent shapes, may vary depending on the technical needs and the state of the art.