Patent Publication Number: US-2017360060-A1

Title: Machine for the production of ice-cream and heat exchange device used in said machine

Description:
FIELD OF THE INVENTION 
     The present invention concerns a machine for the production of ice-cream of the type used in the domestic and/or professional field. 
     The invention also concerns a heat exchange device suitable to be used in the machine and configured so as to increase the heat exchange characteristics during the production of the ice-cream. 
     BACKGROUND OF THE INVENTION 
     Substantially automatic machines to produce ice-cream are known, in the domestic and/or professional field. 
     These machines generally comprise a container for the ingredients to prepare the ice-cream, which is normally holed axially and inserted inside a support body. 
     The support body normally contains inside it a motorized drive mechanism to drive a blade to mix the ingredients, and also at least part of the cooling circuit by means of which the ingredients are taken to the temperature suitable to form the ice-cream. 
     To produce ice-cream it is known to put the container inside the support body. 
     A preparation and/or the ingredients needed to produce ice-cream are put inside the container, as well as a liquid, for example water, milk or other. 
     Once inserted, the ingredients start to cool and are mixed and homogenized by the mixing blade. 
     The support body can also comprise a timing mechanism to set and/or pre-memorize the mixing times needed to obtain the ice-cream according to the methods required by the type of preparation. 
     The mixing of the preparation and the liquid, and the low temperature induced by the cooled walls, promote the formation of the ice-cream until it is ready for consumption. 
     The cooling circuit normally comprises at least an evaporator device that surrounds the walls of the container of the ingredients for the production of ice-cream from the outside, determining a heat transmission by means of which the temperature of the ingredients is lowered to the desired value. 
     If applied in the domestic field, such evaporators must develop a high cooling capacity, given the limited size of the components. 
     In this context evaporators of the coil type are known, inside which a heat exchange fluid flows, for example glycol, or a gel. These known coil-type evaporators define a cavity inside which the container is located, with the ingredients of the ice-cream to be produced. 
     Evaporators are known, for example, associated with a cooling chamber having a substantially cylindrical cavity in which to insert containers with a mating cylindrical shape. 
     Other examples of machines are described, by way of example, in documents U.S. Pat. No. 3,952,538 (US&#39;538), EP 0 179 027 (EP&#39;027) and EP 0 088 351 (EP&#39;351). 
     US&#39;538, EP&#39;027 and EP&#39;351 describe machines for the production of ice-cream that have substantially truncated cone-shaped cavities or cooling chambers inside which containers can be inserted having mating truncated cone shapes. 
     In the machines for the production of ice-cream described in these documents containers can be used that entirely occupy the cavity of the cooling chamber associated with the evaporator. In particular, the containers generally rest on and are supported by a bottom wall of the evaporator or cooling chamber associated therewith. One disadvantage is that inside known evaporators only containers with substantially the same shape and sizes as the cavity defined by the evaporator can be introduced, so that they can be supported and clamped stably inside the evaporator. This is particularly disadvantageous if it is necessary to produce a quantity of ice-cream different from the capacity of the container, for example if it is necessary to produce a much smaller quantity than the capacity of the container, not efficiently exploiting the heat exchange of the evaporator with the container. 
     Furthermore, in known evaporators, there is generally a discontinuous contact between the coils and the support casing, due to which empty spaces are formed, between one point of contact between the coil and the wall and the adjacent one, which can create considerable heat dispersion. 
     Due to these problems there is therefore a need to optimize as much as possible the efficiency of the heat exchange between the evaporator and the container, in particular for machines to produce ice-cream of the domestic type. 
     It must also be noted that, in order to optimize the heat exchange properties, such evaporators are generally made of aluminum or similar materials, and this causes problems in particular in the welding of several coils and/or in the production step. 
     One purpose of the present invention is to obtain a machine for the production of ice-cream that can produce quantities of ice-cream that vary according to the needs and requirements of a user and/or consumer and that therefore allows to use containers with different capacities and sizes. 
     Another purpose of the present invention is to obtain a machine for the production of ice-cream that can improve the efficiency of the heat exchange between evaporator and container. 
     Another purpose is to obtain an evaporator device for machines for the production of ice-cream that can improve the efficiency of the heat exchange. 
     The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. 
     SUMMARY OF THE INVENTION 
     The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea. 
     In accordance with the above purposes, a machine for the production of ice-cream is provided, in a substantially conventional manner, with a support body inside which a container for ingredients can be removably inserted, and a cooling circuit comprising at least an evaporator element. 
     The container comprises a lateral wall and a containing compartment for the ingredients that make up the ice-cream. 
     The evaporator element consists of a plurality of coils which, during use, contact the external surface of the container, either directly or by means of a support casing, in order to achieve the heat exchange that determines the cooling of the ingredients inserted inside the container. 
     According to one characteristic of the present invention, the plurality of coils, together with the corresponding support casing, define a housing seating for the container, with a truncated cone shape in section, and said container has a mating truncated cone shape. 
     Thanks to the truncated cone configuration of the cavity defined by the coils and the support casing on the external face of which the coils are applied, for example welded, it is possible to insert inside it containers with a different size, in order to satisfy specific requirements in terms of quantity of ice-cream to be produced. 
     The mating truncated cone configuration of the cavity defined by the coils and the container of the ingredients also allows an intimate contact or adhesion, whatever the size of the container, between the external surface of the container and the coils of the evaporator element, allowing a support and stable clamping of the container and promoting a better heat exchange and a more effective cooling of the ingredients. 
     In the machine for the production of ice-cream according to the invention, the one or more coils of the evaporator element define a plurality of contact portions, direct or indirect, with the external surface of the support casing and can be compressed against said external surface. 
     According to another characteristic of the present invention, at least the peripheral surface of the coils facing the external surface of the container is compressed, defining a D-shaped section, so as to define a substantially flat contact surface, with respect to the point-by-point contact that occurs when the coils have a substantially circular section. 
     Furthermore, in the case of a compressed section, the contact surfaces of adjacent coils are nearer each other and the empty spaces between adjacent coils, where there is substantially no heat exchange, are reduced. 
     Moreover, in another formulation of the invention, inside the empty spaces defined between the external surface of the support or cooling casing, and the one or more coils, a filler material can be interposed, which can have high heat conductivity. 
     According to another characteristic of the present invention, the coils of the evaporator element are made of copper and, at least at their ends, have an internal core made of weldable material which protrudes from the external covering made of copper to allow welding of two or more adjacent coils to each other and/or to the pipes that feed the cooling liquid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other characteristics of the present invention will become apparent from the following description of some forms of embodiment, given as a non-restrictive example with reference to the attached drawings wherein: 
         FIG. 1  is a front section view of a machine for the production of ice-cream according to the present invention; 
         FIG. 2  is a lateral view of a coil of the evaporator element of the machine in  FIG. 1 , according to the present invention; 
         FIG. 3  is a section view of the evaporator in  FIG. 2 , with a container according to the present invention inserted inside it; 
         FIG. 4  is an enlarged detail of the evaporator in  FIG. 3 , according to the present invention. 
     
    
    
     To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one form of embodiment can conveniently be incorporated into other forms of embodiment without further clarifications. 
     DETAILED DESCRIPTION OF SOME FORMS OF EMBODIMENT 
     We shall now refer in detail to the various forms of embodiment of the present invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described insomuch as they are part of one form of embodiment can be adopted on, or in association with, other forms of embodiment. It is understood that the present invention shall include all such modifications and variants. 
     According to the present invention, a machine  10  for the production of ice-cream, partly shown in  FIG. 1 , can comprise a support body  12 , hollow inside, to contain the ice-cream during its preparation. 
     The support body  12  can for example have a box-like shape, cylindrical, conical or truncated cone, and can be made of heat-insulating material. 
     The support body  12  is provided with an external wall  14  which can substantially delimit its lateral bulk, and with a bottom wall  15  located below the machine  10  in order to support it. 
     According to some forms of embodiment, the support body  12  can be provided with an insulating casing  18  inserted inside it. 
     The insulating casing  18  can have a cylindrical, conical or truncated cone shape, and is hollow inside. 
     The machine  10  is provided with a cooling circuit  20  to cool the ice-cream inside the support body  12 . The cooling circuit  20  can be, for example, a heat pump that exploits in a known manner the heat exchanges deriving from the phase changes that take place inside it. 
     The cooling circuit  20  is a substantially known type and its configuration and structure are not relevant here for the present invention, except for the features that will be described in detail hereafter. 
     The cooling circuit  20  can comprise a condenser, a compressor, an electronic expansion valve, not shown in the drawings, and an evaporator  22 . 
     As shown in  FIGS. 3-4 , the evaporator  22  can consist of one or more coils  29  that delimit a support or cooling casing  24 . 
     The support casing  24  can be smaller than the insulating casing  18  and is disposed substantially inside and resting on the latter. 
     According to the present invention, the support casing  24 , onto the external face of which the coils  29  of the evaporator element  22  are welded, has a truncated cone shape, for the reasons described in more detail hereafter. 
     The support casing  24  can be hollow inside and can define an internal surface  26  and an external surface  27 . 
     According to the present invention, the coils  29  of the evaporator element  22  extend substantially along the whole external surface  27  of the support casing  24 . 
     In particular, the coils  29  can surround the entire support casing  24  in a lower portion thereof. 
     According to one form of embodiment of the present invention, the coils  29  and the support casing  24  are made of copper. 
     The use of this material advantageously allows to facilitate the operations to attach the coils  29  on the external surface  27  of the support casing  24 . 
     The coils  29  can be disposed adhering, with several contact portions  30 , to the external surface  27  of the support casing  24 . 
     According to the present invention, the coils  29  can be provided, longitudinally to their development, with an interspace  31  inside which a suitable cooling liquid or gel can flow, able to be frozen and/or unfrozen according to the functioning of the cooling circuit  20 . 
     Inside the evaporator  22  a container  35  can be removably inserted, having a containing seating  36  to contain, mix and cool the ingredients of the ice-cream. 
     According to the present invention, the container  35  advantageously has a truncated cone shape, substantially mating with at least part of that of the housing seating defined by the truncated cone section of the coils  29 , and/or the support casing  24 . 
     According to one aspect of the present invention, the internal surface  26  of the support casing  24  is configured to support and stably clamp through interference the container  35  inside the housing seating. 
     Thanks to the truncated cone shape of the housing seating defined by the support casing  24 , and hence by the coils  29 , the truncated cone shaped container  35  can be variable in size, and hence not constrained to a specific size, and can be housed stably in the housing seating defined by the support casing  24 . 
     In particular, the invention advantageously allows to use containers  35  having different capacities to produce varying quantities of ice-cream depending on the requirements and needs of a user and/or consumer. 
     Advantageously, as shown by way of example in  FIG. 3 , containers  35  having different sizes, in particular different heights, said containers  35  being selected from a variety of containers  35  in a defined range of heights, can be supported and stably clamped thanks to the truncated cone shape of the housing seating of the support casing  24  and in particular the internal surface  26 . In fact, the truncated cone development of the internal surface  26 , mating with the truncated cone development of the external wall of the container  35 , causes a stable clamping and positioning of the latter, through interference, without its base resting on the bottom of the evaporator  22 , irrespective of the specific height of the container  35 . Furthermore, the clamping through interference of the conical surfaces also causes an optimum adherence, without play, of the surfaces, optimizing the heat exchange. 
     According to one aspect of the present invention, the evaporator  22 , in particular its internal surface  26 , is disposed in contact with, in particular adhering to, the external wall of the container  35  in order to cool it after the cooling of the cooling liquid contained inside the interspace  31  of the coils  29 . 
     According to one form of embodiment of the present invention, the coil  29  has a compressed section shape, for example D-shaped, at least on the face facing toward the external surface  27  of the support casing  24 , and hence toward the container  35 . 
     This section shape allows to increase the overall surface of the contact portions  30  of the coils  29  on the external surface  27  of the support casing  24  and consequently to reduce the empty spaces that are created through a discontinuity of contact with the latter. In this way the heat dispersion of the heat transmitted by the evaporator  22  is reduced, and the heat exchange efficiency is advantageously increased. 
     According to another form of embodiment of the present invention, a filler material M can be provided, preferably with high heat conductivity, interposed between the coils  29  and the external surface  27  of the support casing  24  inside the empty spaces. 
     Providing the material M, it is possible to considerably increase the heat exchange efficiency between evaporator  22  and container  35 , substantially zeroing the empty spaces and creating a substantially continuous contact between external surface  27  and coils  29 . 
     According to another form of embodiment of the present invention, the internal surface  26  can be smooth. By smooth surface we mean a surface that has a linear development without interruptions of material. 
     This characteristic advantageously allows to further increase the heat exchange efficiency between evaporator  22  and container  35  as described above. 
     Between the insulating casing  18  and the external  14  and bottom  15  walls, and between the evaporator  22  and the external wall  14 , empty spaces are created which allow to insulate the container  35  thermally with respect to the outside. 
     As shown in  FIG. 2 , at least the ends of the coils  29  can be provided with internal terminal cores  52  made of easily weldable material to facilitate the welding operations between consecutive coils and/or between coil and cooling liquid feed pipes. 
     According to the present invention, the machine  10  can be provided with a removable lid  40 , which can be disposed resting on the support body  12  to seal the containing seating  36  from the outside. 
     According to the present invention, the machine  10  can be provided with a mixing unit  45  to mix the ingredients contained inside the container  35  during the preparation of the ice-cream, in particular during cooling. 
     The mixing unit  45  can be provided with a shaft  46  rotating around a longitudinal axis X, passing through the center of the machine  10  described here and through a cavity provided axially in the container  35 . 
     A mixing blade  48  can be mounted on the shaft  46 , and can perform the mixing of the ingredients as described above. 
     According to the present invention, the shaft  46  can support and substantially hinge the whole support body  12 . 
     According to some forms of embodiment of the present invention, the machine  10  can be provided with a defrosting system for the evaporator. 
     The defrosting system can provide, for example, electromagnetic sensors to detect the presence of ice inside the evaporator  22 . 
     In this example form of embodiment, once ice has been detected, the defrosting system can command electric resistances to defrost the evaporator  22 . 
     In other forms of embodiment, the defrosting system provides an electrochemical treatment inside the coils  29  of the evaporator  22 . 
     In other forms of embodiment, the evaporator  22  can be defrosted exploiting the inverse principle of a heat pump, i.e. inverting the functioning of the cooling circuit  20 . 
     It is clear that modifications and/or additions of parts may be made to the machine as described heretofore, without departing from the field and scope of the present invention. 
     It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of machines, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.