Patent Publication Number: US-2020288902-A1

Title: Machine and method for preparing beverages

Description:
FIELD OF THE INVENTION 
     The present invention concerns a machine, either automatic or semiautomatic, suitable for preparing beverages, advantageously hot, such as coffee, tea, various infusions, or even just water, and a method for preparing the beverage. 
     BACKGROUND OF THE INVENTION 
     Machines that produce American-style coffee are known, that is, those long coffees also called “drip coffee”, obtained by brewing a quantity of coffee powder with hot water. 
     The Applicant set himself the problem of improving these machines, making them suitable to provide a wide range of beverages, whether cold, or, advantageously, hot. 
     It is known that current machines have a tank for the water, a device for heating the water, a container suitable for positioning a filtering element for the coffee powder, or other aromatic mixture, which is passed through by the hot water, and a receptacle, for example a jug, normally suitable to contain a maximum volume sufficient to fill a certain number of cups or glasses for the end users. 
     The jug is normally associated with its own heating means to keep the coffee beverage dispensed in the jug hot. 
     The heating device is generally put in co-operation with the tank, or put downstream of the tank, for example along a pipe that connects an exit of the tank to the filtering container. 
     When the heating device is activated, the heated water is made to flow from the tank to the filtering container in a known manner, either by convective motion, or by means of a pumping element. 
     The mixture can be introduced or loaded automatically into the filtering element. Means for containing the powdered mixture, and/or metering means and automatic loading means can be present. 
     It is also known that such machines are generally structured and organized to provide the filtering container with the quantity of hot water useful and/or necessary, or to empty the tank. 
     These machines have a number of limitations and/or disadvantages. 
     A first disadvantage is that they dispense a fixed quantity of brewed beverage. 
     Another disadvantage is that they are generally structured to dispense only coffee-based infused beverages, so that they are not structured to dispense tea-based infused beverages or other plant substances. 
     Moreover, such machines are not able to dispense partial quantities with respect to the size of the jug and/or the tank. 
     Another disadvantage of known machines is that they are not suitable to dispense water alone. 
     To partly solve such problems, machines are known that dispense beverages of the “drip coffee” type, which provide the possibility of selecting the quantity of brewed beverage, and also the degree of infusion of the same. 
     For example, machines are known that provide to control the quantity of water to be dispensed by regulating the operation of the heating mean. Such solutions, however, do not allow accurate control of the quantity of water to be dispensed in relation to the selection made by the user, since convective motion is generally unreliable. 
     Machines are also known that provide to control the quantity of water to be dispensed by a pump. These solutions too, however, do not guarantee to dispense the specific quantity of water for each beverage preparation. 
     Known solutions also provide to control the intensity of the beverage dispensed by performing a pre-infusion step and regulating the quantity of water and/or the pre-infusion time on each occasion. 
     Providing a pre-infusion step, however, entails an increase in the time required for dispensing the infused drink, which can therefore exceed the time normally set as a requirement by the “high quality” certification parameters. 
     Moreover, the period of time needed for pre-infusion, during which there is a pause in the delivery of the water, entails a decrease in the heat of the water delivered which influences the qualities of taste of the brewed beverage prepared. 
     From WO-A-2016/034255 an apparatus and a method are known for preparing beverages, in particular espresso type coffee or “cappuccino”, in which the apparatus comprises a brewing chamber, a pump for supplying water from a tank to the brewing chamber, two heating elements to heat the water, and a controller to independently activate the heating elements. This solution, while offering a certain versatility of control of the temperatures reached by the water before the infusion, does not solve the problem of thermal losses of the heated water, as well as presents limits in terms of efficiency of the cycle. 
     The document WO-A-2008/007306 discloses an apparatus for preparing hot beverages comprising a boiler to heat a quantity of water, a pump, and a heating element to heat the water in the boiler. When a thermostat detects that the water has reached the desired temperature, the pump is started. 
     WO-A-2014/195842 refers to a machine for the instantaneous preparation of a hot liquid, or steam, comprising a heating element, a temperature sensor connected to the heating element, a control unit connected to the heating element and the thermostat, and a pump. 
     Known solutions, moreover, are generally suitable only for the preparation of coffee beverages, and do not allow to change the temperature of the water simply and quickly to adapt it to aromatic mixtures of a different type, even for each preparation cycle of a beverage. 
     Furthermore, in known machines, at the end of preparation of the desired beverage, a certain quantity of residual water can remain inside the hydraulic circuit that connects the tank to the filtering element, which can entail problems of flavor and/or hygiene, if the water stays inside for more than a certain period. 
     In addition, the quantities of residual water of a previous preparation can distort the measurement of the water fed, which can result in a brewed beverage which has its predefined characteristics altered. 
     The Applicant thus set himself the purpose of extending the function and functionality of this type of machine, while at the same time improving the efficiency of the dispensing cycle and avoiding the disadvantages identified above, and others. 
     A first purpose of the present invention is to dispense a quantity of beverage as demanded by the user in a precise manner. 
     Another purpose is to dispense the beverage with the desired concentration. 
     It is another purpose to facilitate and simplify the use of this machine by the user. 
     Another purpose is to provide a machine that resets its initial state at the end of each beverage preparation, ensuring the delivery of the quantity of water desired on each occasion, to each operation in a precise manner. 
     Another purpose of the present invention is to provide a machine able to regulate dynamically the water temperature dispensed, according to the request. 
     Another purpose of the present invention is to provide a machine able to regulate the temperature of the dispensed water according to the organoleptic characteristics required in the beverage. 
     Still another purpose of the invention is to provide a machine which, on the one hand, allows to reduce the thermal losses, and on the other to ensure that the water is delivered on each occasion at the precise desired temperature. 
     Another purpose of the present invention is to optimize the efficiency of the water heating. 
     It is also a purpose of the present invention to provide a machine able to minimize energy consumption and to prevent the contamination of the beverages dispensed due to possible water stagnation along the pipes in which the water passes. 
     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, embodiments described here concern a machine for preparing a beverage which allows to dispense, on each occasion, the necessary quantity of water, or also the necessary quantity of water, in relation to the beverage required by a user. 
     The machine according to the invention also allows to optimize, on each occasion, the temperature, or also the temperature, of the heated water according to the beverage required. 
     The machine according to the invention provides, in particular, that a user can choose, by means of an interface, a particular type of beverage, for example a beverage with precise organoleptic characteristics. 
     For example, according to some embodiments, a user can select a coffee beverage, specifying its concentration, or intensity, for example light, normal, or strong, and possibly the quantity of beverage to be dispensed, choosing the size of the container to be used, for example, a jug, cup, mug, glass, or container of different size. 
     The machine comprises a water tank, of a known type, which can be filled on each occasion, either periodically or continuously. 
     Means to indicate the volume of water are possibly present in the water tank, said means being associated with signaling means and/or means to control the water delivery into the tank. 
     According to a variant, instead of the tank, or in association with it, a continuous water source can be provided. 
     If the tank is associated with a continuous water source, it can be provided that the user can choose the preferred source of supply: tank or direct. 
     The tank, advantageously, is placed in fluid communication, by means of at least one circuit, with the filtering container suitable to contain the aromatic mixture. 
     According to some embodiments, the filtering container can be standard, that is, suitable to contain a desired quantity of aromatic mixture on each occasion. 
     For example, the aromatic mixture can be a powdered mixture and/or with a desired grain size, in leaves, or portions thereof, of coffee, tea, or other vegetable substance, or other. 
     According to another variant, the machine comprises a pump suitable to pick up the water from the tank and supply it to the filtering container. 
     According to another variant, the pump has an advantageously adjustable and controllable flow rate. 
     According to some embodiments of the invention, between the tank and the filtering container, there is an instrument suitable to control the quantity of water dispensed. 
     Along the water path there is also a device to heat the water in transit. 
     According to other embodiments, the heating device comprises a boiler. 
     According to some embodiments, the boiler comprises at least one transit channel associated with at least one heating element disposed at least along most of its longitudinal extension. 
     According to a variant, the internal wall of the transit channel is lined with a material which does not allow the sedimentation of the limescale present in the water. 
     The combination of the heating element and the boiler is, however, sufficient to support the increased water delivery provided at the desired temperature. 
     According to a variant, the heating element is active only in relation to the specific delivery. 
     According to another variant, the heating element is always active. 
     According to another variant, the heating element is always active but with different heating capacities, for example between the dispensing function and the standby function. 
     It is another variant to provide that the heating element is active, or can be activated, according to the base temperature set during the standby function. 
     According to some embodiments, the boiler has at least a substantially vertical extension in such a way as to optimize heating efficiency and reduce thermal losses to a minimum. 
     According to other embodiments, the boiler has an accumulation zone for the water inside it. 
     According to other embodiments, the boiler comprises two heating elements, autonomous and independent of each other, which can be selectively activated and/or deactivated in relation to specific requirements. 
     According to some embodiments, sensor means are provided to control that the dispensed water has the desired temperature. 
     The sensor means for temperature control can be disposed downstream of the boiler, or in relation to the terminal part thereof. 
     According to some embodiments, the machine according to the invention comprises a control and command unit configured to regulate the functioning thereof, subjecting one or more parts, depending on the beverage selected by the user. 
     According to some embodiments, the control and command unit communicates with the sensor means to regulate the functioning in such a way as to regulate the temperature of the water delivered according to the beverage selection made by the user. 
     According to a variant, the machine allows to modify the functioning parameters of one or more components (pump, heating device, infusion time, etc.) depending on the specific drink selected by the user by means of the interface. 
     The machine, according to another variant, is provided with a diffusion head configured to dispense water, at the desired temperature, in a shower, jet, or mist, in relation to the type of aromatic mixture to be infused, and to the type and quantity of beverage to be prepared, that is, depending on the user&#39;s request. 
     According to a variant, the machine has means suitable to define the maximum volume of the container, where it is provided to be able to use various types of containers. 
     According to another variant, means are provided that indicate the useful volume to the user, so that the user can indicate the degree of filling of the container, that is, the physical quantity. 
     In this case, the means that can be used by the user also include the possibility for the user to indicate the degree of filling of the container with the dispensed beverage. 
     The filtering container of the aromatic mixture suitable to create the brewed beverage, according to one variant, can have controlled dispensing means in order to obtain the degree of infusion required by the user on each occasion. 
     Possible heating means located under the receiving jug, according to a variant, can be subject to the characteristics of the beverages as chosen by the user. 
     The embodiments described here also concern a method for preparing a specific quantity of beverage with the organoleptic characteristics selected by a user. 
     The method according to the invention provides that when the user has selected the desired beverage, an operation to prepare the beverage is started. 
     At the start of the preparation, the method provides initially to activate the pump to fill the boiler with the water to be heated, reaching the temperature sensor means, and subsequently to activate the heating element until the water inside the boiler reaches a temperature consistent with the selected beverage. 
     In this way, the beverage is always dispensed at the desired temperature, regardless of the time interval elapsed since the previous beverage preparations. 
     According to some embodiments, when the temperature sensor means detect a temperature of the heated water corresponding to the specific temperature, the control and command unit starts the pump again to dispense the quantity of water corresponding to the selection made to the filtering container and to the outlet. 
     According to a variant, based on the selection made, the control and command unit predisposes the various operating components according to the organoleptic characteristics and/or the temperature selected by the user. 
     According to other embodiments, at the end of the dispensing of the beverage, the method provides to restore the initial conditions of the machine, so as to guarantee, on each occasion, for each beverage selected, both to heat the water to the correct and specific temperature, and also to provide the defined quantity thereof. 
     According to other embodiments, at the end of the dispensing of the beverage, the method provides to deactivate the pump, leaving the heating device active for a certain time so as to empty the circuit by means of a convective motion, and possibly to dry the water remaining inside it. 
     In this way, possible residual water is prevented from remaining in the circuit and distorting the measurement of the quantity of water dispensed in a subsequent beverage dispensing operation. 
     By drying the circuit downstream of the pump, in fact, it ensures that the water fed to the filtering element for each beverage preparation operation corresponds to that actually required by the selection made by the user, thus avoiding both the preparation of unsuitable or too diluted beverages, and also avoiding dispensing excessive quantities of liquid with respect to the container selected, and used by the user. 
     According to a variant, periodically, or in relation to a signal received from the control and command unit, the method can provide a function for cleaning the boiler, to eliminate any sedimentation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other characteristics of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein: 
         FIG. 1  is a schematic view of a machine for preparing beverages, according to embodiments described here; 
         FIG. 2  is a detailed schematic view of a component of the beverage preparation machine in  FIG. 1 ; 
         FIG. 3  is a schematic view of the control system of the beverage preparation machine according to embodiments described here. 
     
    
    
     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 embodiment can conveniently be incorporated into other embodiments without further clarifications. 
     DETAILED DESCRIPTION OF SOME EMBODIMENTS 
     Forms of embodiment described here with reference to  FIG. 1  concern a machine  10  for the preparation and delivery of a hot or cold beverage, starting from an aromatic mixture  11  in powder form or ground, by brewing, infusing it or mixing it with water. 
     According to some embodiments, the machine  10  according to the invention allows a user to select the type and quantity of beverage to be prepared by means of a user interface  35 . 
     According to some embodiments, the user interface  35  can comprise pressure keys, selection knobs, and/or a touch screen, by means of which the user can select the intensity of the beverage to be dispensed, for example between light, normal, or strong, and the quantity thereof, that is, the size of a receptacle  15  to be used, such as a jug, half jug, cup, mug, glass, or suchlike. 
     The machine  10  comprises a tank  12  for the water, fluidly connected to a filtering container  13  suitable to contain the aromatic mixture  11  to be infused, and to an outlet for the beverage  14  through which the infused beverage can be dispensed into the suitable receptacle  15 . 
     According to some embodiments, the output for the beverage  14  is associated with dispensing means  41 , for example a valve  48 , which can be selectively activated to open or close the output for beverage  14 , and/or to regulate the flow rate through it. 
     The tank  12  can generally be a container configured to contain a certain quantity of water to prepare a beverage. For example, the volume of the tank  12  can be equal to at least the quantity of water needed to fill a jug. 
     The tank  12  can be provided with an introduction aperture  12   a , associated with a lid  60 , through which water can be introduced thereto, and an outlet aperture  17  from which the desired quantity of water can be taken on each occasion. 
     According to some embodiments, the tank  12  can be positioned inside a housing  20  of the machine  10 , or attached thereto, possibly removably, to be subjected to cleaning and/or for filling. 
     According to a variant, the tank  12  can be associated with a continuous water supply source. 
     According to some embodiments, the filtering container  13  for the mixture can have a funnel shape, and a filtering element  18  can be inserted therein, suitable to retain the solids of the aromatic mixture  11 , preventing them from being dispensed together with the infused drink. 
     According to some embodiments, the filtering container  13  can be provided with manual or automated closing valves  48 , to leave the aromatic mixture  11  infusing for a period of time before dispensing the brewed beverage into the receptacle  15 . 
     According to some embodiments, access means  61  and/or movement means can be provided, configured to allow access to the filtering container  13  in order to introduce on each occasion a desired quantity of aromatic mixture  11  and/or remove it together with the possible filtering element  18  at the end of delivery of the beverage prepared. 
     According to some embodiments, the machine  10  comprises a diffusion head  19 , disposed above the filtering container  13  and configured to dispense the water arriving from the tank  12  above the aromatic mixture  11  so as to increase the contact between the water and the aromatic mixture  11 . 
     According to some embodiments, the diffusion head  19  can be configured to dispense the water in a shower, jets, mist, or also possibly in a continuous flow. 
     The machine  10  also comprises a heating device  21 , disposed between the tank  12  and the filtering container  13 , and configured to heat the water in transit to the desired temperature. 
     According to some embodiments, the heating device  21  is disposed along the hydraulic circuit  22  that connects the tank  12  to the diffusion head  19 . 
     According to some embodiments, the heating device  21  comprises a boiler  24  having at least one conduit  25  defining a transit channel  25   a  for the water to be heated, and at least one heating element  26  associated with it. 
     According to some embodiments, the transit channel  25   a  defines a segment of the circuit  22 . According to possible solutions, the internal walls of the transit channel  25   a  have a suitable shape to extend the useful heat exchange surface. 
     According to some embodiments, the transit channel  25   a  is internally lined with a material which does not allow the sedimentation of limescale. 
     According to other embodiments, the boiler  24  comprises at least one first branch  24   a  and at least one second branch  24   b.    
     The second branch  24   b  is disposed downstream of the first branch  24   a  along the path of the water from the tank  12  to the diffusion head  19 . 
     According to some embodiments, the second branch  24   b , or larger branch has a longitudinal extension greater than the first branch  24   a , or smaller branch. 
     According to some embodiments, the two branches  24   a ,  2   b  have their respective axis of longitudinal development not aligned along a common straight line. 
     In other words, a branch, in particular the larger branch  24   b , develops substantially in a vertical direction, for the reasons already stated, and for what reported in the following, while the other branch, that is the smaller branch  24   a , has at least one substantially horizontal segment, or at least partly curved, having an angle with respect to the larger branch  24   b.    
     According to some embodiments, the larger branch  24   b  is disposed in a vertical direction, so as to reduce thermal losses to a minimum. 
     When the water flows in a vertical segment, in fact, it is in direct contact with all the internal walls of the transit channel  25   a , so that the heat exchange surface is maximized. 
     In the horizontal segments, on the contrary, if the pressure and/or the flow of the fed water is not high enough, the quantity of water fed could be insufficient to fill the section of the transit channel  25   a , thus reducing the usable heat exchange surface. 
     The inlet of the boiler  24  in particular is positioned at a lower height than its output. 
     According to some embodiments, the length of the larger branch  24   b  is predominant with respect to the overall vertical extension of the circuit  22 . In other words, the larger branch  24   b  extends for the most part of the vertical longitudinal development of the circuit  22 . 
     According to some embodiments, the larger branch  24   b  extends substantially to the proximity of the diffusion head  19 , so as to eliminate or at least reduce as much as possible the thermal losses downstream of the larger branch  24   b.    
     In this way it is ensured that the water delivered into the filtering container  13  is on each occasion at the desired and required temperature. 
     According to some embodiments, the boiler  24  can be L-shaped, providing that the smaller branch  24   a  is disposed at least partly along a horizontal direction, while the larger branch  24   b  develops substantially vertically. 
     According to possible embodiments, the boiler  24  comprises an accumulation zone  24   c , in which possible water residues present in the boiler  24  can be collected at the end of the water supply. 
     The accumulation zone  24   c  is preferably disposed upstream of the larger vertical branch  24   b  along the path of the water. 
     According to some embodiments, for example in the case where the boiler  24  is L-shaped, the accumulation zone  24   c  can also comprise at least a part of the first branch  24   a.    
     According to some embodiments, the boiler  24  can comprise two branches  24   a ,  24   b , both disposed along a vertical direction, located on one side and the other of the accumulation zone  24   c  which defines the intermediate connecting zone. 
     According to possible variant embodiments, the boiler  24  can be U-shaped or J-shaped. 
     The U or J shape is particularly advantageous since the water possibly present inside tends to accumulate in the accumulation zone  24   c , allowing it to be dried by activating the heating element  26 . 
     According to some embodiments, the heating device  21  comprises two or more heating elements  26 ,  27  disposed on opposite sides of the conduit  25 . 
     According to other embodiments, the heating elements  26 ,  27  can be electrical resistances disposed along most of the longitudinal development of the boiler  24 , in a linear manner or in a spiral. 
     According to a variant, the heating elements  26 ,  27  can be activated so that they reach the target temperature, or to modulate their temperature. 
     According to some embodiments, the heating elements  26 ,  27  are autonomous and independent of one another. In particular, the heating elements  26 ,  27  can be selectively fed according to the temperature to which the water in transit is to be heated and/or depending on the state of progress of the beverage preparation operation. 
     According to some embodiments, the heating elements  26 ,  27  have the same power, that is, each one corresponds to 50% of the overall power of the heating device  21 . 
     According to possible variants, the heating elements  26 ,  27  have different powers from each other, thus allowing a further modulation of the heating temperature. 
     For example, according to possible implementations, the heating elements  26 ,  27  can have proportional powers, for example 60%-40%, 70%-30%, 75%-25%, 80%-20%, or intermediate values. 
     According to some embodiments, the machine  10  also comprises temperature sensor means  28  disposed along the circuit  22  and configured to detect the temperature of the water in transit. 
     According to some embodiments, the temperature sensor means  28  are disposed downstream of the boiler  24  so as to detect the temperature of the water in transit near the area in which it comes into contact with the aromatic mixture  11 . 
     According to possible variants, the temperature sensor means  28  can be positioned inside the boiler  24 , possibly in correspondence with the exit end of the transit channel  25   a.    
     According to other variants, temperature sensor means  28  can be provided both integrated in the boiler  24  or in the heating device  21 , and also disposed downstream thereof and possibly upstream as well, so as to be able to regulate the supply of the one or more heating elements  26 ,  27  also depending on the difference in water temperature detected upstream and downstream of the heating device  21 . 
     According to possible solutions, the temperature sensor means  28  can comprise a Negative Temperature Coefficient (NTC) resistance, located inside a pipe defining a segment of the circuit  22 . 
     According to some embodiments, the machine  10  comprises a pump  30  disposed along the circuit  22  and configured to draw the water from the tank  12  and feed it through the boiler  24  toward the filtering container  13 . 
     According to some embodiments, the pump  30  can be selectively activated to take on each occasion the quantity of water suitable for preparing the quantity of beverage selected by the user. 
     According to some embodiments, the pump  30  is of the adjustable flow type, so that it is possible to regulate the speed of the water that passes through the boiler  24  and through the aromatic mixture  11 . 
     According to some embodiments, the machine  10  comprises flow detection means disposed in the tank  12  and/or along the circuit  22  to measure the quantity of water in transit through it. 
     According to some embodiments, the flow detection means comprise a flowmeter  32 . 
     According to some embodiments, the flowmeter  32  is located upstream of the pump  30 , allowing a faster and more efficient detection of the flow rate and therefore a dynamic and real-time regulation of the pump  30 . 
     According to some embodiments, the machine  10  comprises a control and command unit  34 , configured to regulate the functioning of the heating device  21  and the pump  30  on the basis of selection made by a user, to heat the water to a temperature suitable for preparation of the selected beverage. 
     According to some embodiments, the control and command unit  34  can comprise, or be connected to, a memory unit  33  in which the optimum temperature and/or water speed values can be memorized for each beverage that can be selected by the user, that is, for each combination defined according to the type of aromatic mixture  11 , and/or the intensity of the beverage and/or the selected quantity of the beverage. 
     The regulation of the temperature makes it possible to prepare, in addition to coffee, tea-based beverages or other vegetable substances, which generally require lower infusion temperatures than those required for coffee. 
     By way of example, while for a coffee drink a water temperature preferably comprised between about 92° C. and about 96° C. is required, to prepare tea a water temperature comprised between about 70° C. and about 90° C. is preferable, depending on the quality of the tea used. 
     According to some embodiments, described with reference to  FIGS. 1 and 3 , the control and command unit  34  is also connected to the temperature sensor means  28  and to the flowmeter  32  to receive the data detected by them. 
     The control and command unit  34  is also configured to compare the data received with the values memorized in the memory unit  33 . 
     Depending on the selection made by the user on the type and/or quantity of beverage to be prepared, and on the basis of the data received from the temperature sensor means  28  and the flowmeter  32 , the control and command unit  34  can regulate the flow rate of the pump  30  and/or the switching on and off of the heating element  26 ,  27  of the heating device  21  to obtain the beverage selected. 
     According to some embodiments, the control and command unit  34  receives in real time the data relating to the flow rate and temperature of the water and dynamically regulates, with a feedback control, the pump  30  and the heating device  21 . 
     According to a variant, the control and command unit can regulate the flow rate of the pump  30  and activate the heating device  21  by means of a PID type regulation system, or by other suitable means. 
     According to these embodiments, for example, the PID regulation system can receive as inputs the flow rate of the water detected by the flowmeter  32  and the temperature of the water detected by the temperature sensor means  38  and supply as outputs the flow rate of the pump  30  and the power supply of the heating element  26 ,  27  of the heating device  21 . 
     In particular, given the same temperature of the heated water, the control and command unit  34  can decrease or increase the flow rate of the pump  30 , and hence the water speed, respectively, to extract more or fewer substances from the aromatic mixture  11 , and thus regulate the intensity of the beverage. 
     For example, it can be provided that the control and command unit  34 , to modify the flow rate, acts on the feed power of the pump  30 , in such a way as to increase or decrease the number of revs of the motor of the pump. 
     According to other embodiments, the pump  30  can be selectively activated/deactivated to deliver the water in pulses, so as to perform a “pour-over” infusion, that is, to obtain a particularly slow extraction of the substances from the aromatic mixture  11 . 
     According to other embodiments, the control and command unit  34  can selectively switch on and off the at least one heating element  26 ,  27  according to a certain duty-cycle, so as to keep it at the suitable temperature. 
     According to other embodiments, the control and command unit  34  autonomously and independently switches on and off each heating element  26 ,  27 , so as to suitably modulate the temperature of the heating device  21  according to the operations to be performed. 
     For example, the temperature of the heating device  21  can be modulated on the basis of slow preheating operations, temperature maintenance, high temperature delivery, or other. 
     The possibility of dynamically modifying both the flow rate of the pump  30  and also the temperature of the heating device  21 , and hence of the water, allows to optimize the extraction of the substances of the aromatic mixture  11  to obtain the desired intensity of the beverage as selected by the user, without needing to provide a pre-infusion step, thus meeting the requirements for high quality. 
     According to possible variants, however, it can be provided to perform a pre-infusion step of the aromatic mixture  11  before dispensing the brewed beverage. 
     According to other embodiments, the housing  20  is provided with a support base  37  for the receptacle  15 . 
     According to possible variants, the support base  37  can be provided with additional heating means  38  which can be selectively activated by the control and command unit  34  to keep the beverage dispensed in the receptacle  15  warm. 
     For example, the additional heating means  38  can comprise a Positive Coefficient Temperature (PCT) resistance. 
     According to possible embodiments, not shown, other support bases can be provided, possibly folding or mobile, configured to bring the receptacle  15  closer to the outlet of the beverage  14  so as to prevent any splashes of the beverage, if the receptacle  15  used is either a cup, or a glass. 
     The embodiments described here also concern a method for preparing a beverage which, on the one hand, provides to dispense the selected beverage at its respective optimum temperature, and on the other hand to restore the same conditions of the machine  10  at the end of each beverage preparation operation. 
     The method for preparing a beverage according to the invention provides to receive, in a control and command unit  34 , a command relating to a type and quantity of beverage to be prepared by a user by means of a user interface  35 . 
     Based on the command received and on the parameters memorized, the control and command unit  34  can determine the values of water temperature and speed specific to the selected beverage and can selectively activate the pump  30  and the heating element  21  to obtain the above values. 
     According to some embodiments, at the start of a beverage preparation operation, the method provides to activate the pump  30  at least to fill the circuit  22  with water, preferably at least up to the temperature sensor means  28 . 
     In this step of activating the pump  30 , the heating device  21  can be kept switched off. 
     Subsequently, the method provides to deactivate the pump  30  so as to stop the water supply to the circuit  22  and to activate the heating device  21  to heat the water inside it to the specified temperature value. 
     This, in particular, is made possible by the particular configuration of the boiler  24 , thanks to which the water remains inside it even when the pump  30  is deactivated, and can therefore be heated rapidly and effectively. 
     According to some embodiments, the temperature sensor means  28  are advantageously located in a vertical pipe segment, so that the water supplied by the pump  30  remains confined inside the pipe itself even when the pump  30  is deactivated. 
     According to some embodiments, in order to obtain a rapid heating of the heating device  21 , the control and command unit  34  can switch on both the two or more heating elements  26 ,  27 . 
     Subsequently, when the water downstream of the heating device  21  has reached the specified temperature value, the method provides to activate the pump  30 , possibly regulating its flow rate, to infuse the aromatic mixture  11  and dispense the selected beverage in the receptacle  15 . 
     According to some embodiments, during the dispensing step, the control and command unit  34  can selectively switch on and off one or both of the heating elements  26 ,  27 , to keep the specified temperature value. 
     At the end of the beverage dispensing operation, the method provides to deactivate the pump  30 , stopping the water supply in the circuit  22 , and to restore the initial conditions of the machine  10 . 
     According to some embodiments, in particular, the method provides to empty and dry the circuit  22 , leaving the heating device  21  activated for a period of time suitable to empty the circuit  22  by means of a convective motion, and possibly to empty the water remaining inside it. 
     The form of the boiler  24  allows in particular to accumulate any residual water in the accumulation zone  24   c , allowing it to be removed effectively. 
     According to some embodiments, during the emptying step, the control and command unit  34  can selectively switch on and off one, or both, the heating elements  26 ,  27 . 
     According to some embodiments, the emptying step is carried out immediately at the end of the delivery of the beverage. In this way, the water remains inside the circuit  22  for a negligible time, allowing to prevent unwanted contamination of subsequent beverages. 
     In the case of sequential delivery, it is advantageous to keep the heating device  21  active at the end of each single dispensing operation, since it reduces the energy consumption for the subsequent delivery. 
     In this case, the heating device  21  remains hot and therefore the water for subsequent delivery reaches the desired temperature in less time. 
     According to other embodiments, the method can provide, at least in the case where the selected receptacle  15  is a jug, to activate the additional heating means  38  to keep the dispensed beverage hot. 
     It is clear that modifications and/or additions of parts can be made to the machine  10  and method for preparing a beverage 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 machine  10  and method for preparing a beverage, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.