Abstract:
The invention refers to a moka coffee machine, basically traditional, modified in order to obtain an expresso coffee without altering the organoleptic properties thereof. The machine according to the invention allows to control the temperature of the water inside the boiler, and to prepare the drink without having the water reaching exceedingly high pressures.

Description:
This application is the U.S. national phase of International Application No. PCT/IT2005/000321 filed 8 Jun. 2005 which designated the U.S. 
     BACKGROUND OF THE INVENTION 
     The present invention refers to a coffee machine, and in particular to a coffee maker of the kind commonly designated by the term “moka”, and to an improved method for preparing a coffee-flavoured drink. 
     Moka coffee makers are mainly made of alloys of steel, aluminium or ceramics and provide some indisputable advantages, such as their simplicity of use and maintenance and their low purchase price. 
     However, it is well-known that the coffee prepared with such coffee makers is of lower quality with respect to the one that can be had at a bar. 
     The principles exploited for preparing expresso coffee are basically different from those exploited in moka coffee makers; this is basically the reason for the differences in quality, and above all in taste. 
     In coffee prepared at home in a moka coffee maker, the water in the boiler reaches high temperatures (greater than 100° C.) due to the pressure that is generated in the latter and then contributes to allow water to rise and flow through the coffee-containing filter up to the top container collecting the prepared drink. 
     However, the above-described method, above all owing to the high temperatures of the water coming into contact with the coffee powder, sensibly alters the organoleptic properties of the coffee itself, burning most of the fatty component, the one giving “body” to the drink and producing the well-known aroma. 
     Therefore, the resulting coffee generally is a very fluid drink, of low thickness and body and scarcely aromatic. Proof of the above is the fact that the coffee thus prepared is never accompanied by a high quantity of “cream”, significant of the preservation of such fatty components. 
     Moreover, the temperature reached by the water during the preparing is also excessive for an immediate consumption, forcing the user to wait for the coffee to cool down to an acceptable temperature. 
     The alternative to such a preparing is just that of an expresso coffee prepared as at a bar. 
     In fact, to obtain a high-quality coffee these professional machines must adopt a set of technical contrivances allowing a very accurate control of all the parameters coming into play, from temperature to water pressure. 
     At coffee bars, the famed expresso coffee (an Italian source of worldwide pride) is obtained by using professional machines, which however are very sophisticated and expensive, in the operation as well as the maintenance thereof. 
     A household alternative to professional machines for coffee bar use is represented by small expresso coffee machines, which on principle should work similarly to the former and therefore prepare an alike coffee. 
     However, it has to be pointed out that while a professional machine used at a coffee bar is controlled at all times, used with the right coffee and its maintenance and cleaning is regularly carried out, often household machines are improperly used, the coffee used is not always the right one, the water used is nearly always rich in calcareous deposits, thereby deteriorating over extremely short times. On the other hand, those are machines belonging to a sophisticated typology, adapted to household operation by often coming to compromises between costs and quality. 
     SUMMARY OF THE INVENTION 
     The technical problem underlying the present invention is to provide a moka coffee maker, to be commonly used at home without any specific care, overcoming the drawbacks mentioned hereto with reference to the known art. 
     Such a problem is solved by a coffee machine as described. 
     Moreover, a further object of the present invention is to provide a method for preparing a coffee-flavoured drink. 
     The present invention, by overcoming the mentioned known-art problems, entails several evident advantages. 
     The main advantage lies in obtaining a rich and tasty coffee, alike and even better than that of a coffee bar, in an extremely simple manner, at home, by means of a coffee maker basically identical to that commonly found in households. 
     This, in order to obtain an ever-improved coffee, entails an evident advantage in economic terms. In fact, suffice it to remember that the moka coffee maker is surely the one with a lower unitary cost per coffee, whereas all other solutions proposed, from the most professional ones to the ones imitating them at household level, entail markedly higher unitary costs. 
     Moreover, the purchase prices of a coffee maker according to the present invention will be almost the same of today, and the costs of assistance will be next to zero, as the latter does not necessarily envisage the use of specific electric or mechanical tools. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages, features and the operation modes of the present invention will be made apparent in the following detailed description of some embodiments thereof, given by way of a non-limiting example. Reference will be made to the figures of the annexed drawings, wherein: 
         FIG. 1A  is an exploded view of a first embodiment of a moka coffee machine according to the present invention; 
         FIGS. 1A-1  is a detailed view of a quick connector; 
         FIG. 1B  is an exploded view showing a variant of coffee maker with a dispensing spout; 
         FIG. 2  is a section of the coffee maker of  FIG. 1A ; 
         FIGS. 3 and 4  refer to a second embodiment of a moka coffee machine according to the present invention; 
         FIG. 4A  is a detailed view of a quick connector; 
         FIGS. 5 and 6  refer to a third embodiment of a moka coffee machine according to the present invention; 
         FIGS. 7 and 8  refer to a variant of the coffee machine of  FIGS. 5 and 6 ; 
         FIG. 9  shows an embodiment with a compressed gas tank; and 
         FIG. 10  shows an embodiment using a micro compressor. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is based on the observation of the fact that, in order to obtain an expresso coffee exhibiting the correct organoleptic qualities, the right body proper to expresso coffee and a good aroma, some parameters of the method for preparing the drink are of fundamental importance; in particular, the temperature and the pressure of the water transiting the coffee powder in the filter. 
     Initially referring to  FIG. 1A , it shows an exploded view of a first embodiment of a coffee machine according to the present invention. 
     More particularly, a moka coffee maker  1  consists of a boiler body  2  housing water to be heated on a burner or the like for preparing the coffee-flavoured drink. 
     Onto the boiler  2  it is screwed, or secured in another equivalent manner, a dispenser  3 , optionally associated to a container  4  that will contain the drink once prepared. 
     Between the boiler  2  and the dispenser  3  it is interposed a first coffee-holding filter  5  holding the coffee powder for preparing the drink. 
     Preferably, a second filter  6  is placed above the first one, to prevent the coffee powder from ending up in the container along with the drink. 
     According to a well-known alternative, illustrated in  FIG. 1B , the container could be replaced by a support holding cups in which the dispenser, provided with a dispensing spout, directly delivers the prepared drink. 
     According to the present invention, the coffee maker  1  comprises means for controlling the temperature of the water inside the boiler  2 . 
     In particular, according to such a first embodiment, such temperature controlling means  7  consists of a thermometer, secured on the boiler body, whose indication is visible from outside. According to an extremely simple variant embodiment, it can be implemented by means of a temperature-sensitive graduated strip  7 , secured on the outside of the boiler body  2 , e.g. of the kind in which different strip portions vary their coloration at a certain temperature. Of course, as it will be described hereinafter, different variant embodiments could be envisaged. 
     Thanks to the presence of this thermometer, the person preparing the coffee could monitor the temperature of the water in the boiler during the preparing of the drink. In particular, the temperature deemed optimal to the ends of the present invention is in the neighbourhood of 90° C. 
     Hence, when the thermometer signals the reaching of such a predetermined temperature the coffee maker could be removed from the heat source, or the latter could be turned off, in a manner such as not to further increase the temperature of the water in the boiler. 
     Moreover, on the boiler body  2  of the coffee maker according to the present invention, it is present means  8 ,  9  for inletting a gaseous-state fluid in the boiler. 
     E.g., such means could advantageously comprise a one-way valve  8  having an external connection to the boiler, preferably of a quick type (see  FIGS. 1A-1 ), to which there could be connected a device  9  providing the gaseous fluid, e.g. an accumulation tank. 
     The fluid to be used should be an inert gas, in no way reacting with the water in the boiler and, of course, that may be provided in the gaseous state at the temperatures into play (80° C.-90° C.). In particular, it could be air, nitrogen, carbon dioxide, or other gas. 
     Advantageously, the tank providing the gas may be such as to accumulate a remarkable quantity thereof in compressed form, so as to constitute a useful reserve for preparing several coffees; e.g., it could be a compressed gas bottle  9 . 
     Then, upon reaching the ideal temperature for preparing the drink, the bottle  9  is connected to the valve  8  via a feed duct. Then, a certain quantity of compressed gas is introduced into the boiler  2 , causing a pressure increase therein that forces the heated water to rise into the container through the duct of the filter  5 . Evidently, for a correct operation the pressure thus generated inside the boiler should be greater than the atmospheric pressure. 
     Thus, the temperature of the water coming into contact with the coffee is not so high as to spoil most of the organoleptic features of the coffee; therefore, the resulting drink will have, upon reaching the container  4 , the appearance, the aroma and the taste of an excellent expresso coffee, very similar to that prepared with a professional machine for coffee bar use. 
     The first embodiment of the present invention described hereto is that representing more simply the inventive concept underlying the present invention and allowing the implementation thereof in the most simple and inexpensive manner. 
     Evidently, always within the scope of the same inventive principle, there could be envisaged some variant embodiments allowing an easier use of the coffee maker according to the present invention and requiring a lesser intervention by a person wishing to prepare the drink. 
     Therefore, with reference to  FIGS. 3 and 4 , hereinafter it will be described a second embodiment of a coffee machine according to the present invention. 
     Such a second embodiment refers to a moka coffee maker  10 , comprising a boiler body  12 . To the boiler body  12  it is connected a handle  23 . The handle  23 , besides from carrying out the common function of handle for gripping the coffee maker, is configured in a manner such as to house the means  14 ,  18 ,  19  for inletting gas inside the boiler. In particular, it is provided a compressed air bottle  19 , advantageously equipped with a quick connector (see  FIG. 4A ) so as to be removable and replaceable with extreme ease, through the opening  18 , closeable by a lid  20 . 
     Therefore, the bottle  19  is connected, via a duct internal to the handle  23 , to a one-way valve opening it on the inside of the boiler  12 . 
     In addition, it is provided means  7 ,  17  for controlling the temperature. More specifically, such means comprises, inside the boiler  12 , a thermometer probe  17  detecting the temperature of the water. The probe is connectable to a signalling circuit SC, external to the boiler; when the temperature reaches a predetermined threshold, e.g. of 90° C., said circuit provides a signal via signalling devices such as a thermometer, a LED  15  and/or a buzzer  16 . 
     Such a signal can also be used to enable the operation of activation means  14 , e.g., an activation pushbutton allowing the operator to let gas flow inside the boiler. 
     Evidently, the number of times the coffee maker can operate without having to replace the compressed gas bottle  19  basically depends on the modes with which the gas itself is accumulated in the bottle. The greater the storage pressure, the greater the number of operation cycles of the bottle. Therefore, these parameters will depend also on the nature of the gas. 
     To the ends of the present invention, it is likewise important to be able to adjust the pressure reached inside the boiler. In fact, depending on the coffee powder used and above all on its grounding, such a pressure is decisive. In particular, the more finely ground the coffee powder is, the greater the pressure inside the boiler will be. 
     For this purpose, the coffee maker could advantageously be provided with a pressure and/or flow regulator, mounted onto the duct for inletting gas in the boiler, allowing to obtain the desired pressure value. 
     The regulator could also be of a presettable kind, optionally among a finite number of choices, so as to set the pressure value depending on the coffee used. 
     Next,  FIGS. 5 and 6 , refer to a third embodiment of a coffee machine according to the present invention. 
     According to such an embodiment of the invention, a coffee machine  100  comprises a coffee maker  101  comprising a boiler body  102  onto which it is mounted a one-way valve  108  for inletting a gas inside of the boiler itself. 
     Moreover, inside the boiler  102  it is advantageously installed a thermometer probe  107  for metering the water temperature during the operation of the coffee maker. Such a probe  107  will have the corresponding electric contacts connected to a connector located outside of the boiler body. 
     Alternatively, onto the boiler there could be provided different means for controlling the water temperature, like e.g., a thermometer visible from the outside of the boiler itself. 
     In addition, the coffee machine  100  comprises a base  110  onto which there may be housed the coffee maker  101 . 
     Advantageously, the base  110  is equipped with a connecting region  113  provided with quick connectors  114 ,  115 , respectively, for a duct carrying the gas to be introduced under pressure into the boiler and, optionally, for the electric contacts of the thermometer probe  107 . 
     In order to prepare the coffee-flavoured drink, the coffee maker  101 , upon having normally been loaded with water and coffee powder, can be placed on a burner, as usual. 
     When the water inside the boiler reaches the desired temperature, and this can be checked through the boiler thermometer or according to alternatives described hereto or equivalent ones, the operator could position the coffee maker  101  onto the base  110  in a manner such that the one-way valve  108  be connected to the connector  114 . Advantageously, the base  110  could be shaped so as to allow a correct positioning of the coffee maker. 
     Then, the operating means could activate the gas flow to the inside of the boiler  102 , by means of the connector  114 . 
     In this case, the base  110  could comprise a compressed gas tank  160 , as in the above-described embodiments, operated, e.g., by means of a solenoid valve  161 . See  FIG. 9 . 
     Alternatively, the base  110  comprises an micro compressor  162  for air that, when operated, provides compressed air to be introduced in the boiler body. See  FIG. 10 . 
     Moreover, the base could provide a pressure and/or flow regulator, adjustable by means of an adjustable control device  118 , in order to set various desired pressure values inside the boiler, depending on the different kinds of coffee used. 
     Advantageously, according to a variant of such a third embodiment illustrated in  FIGS. 6 and 7 , the base  110  may further comprise a heat source  111 , e.g. an electric cooker, powered through the network supply  112 . 
     More particularly, in order to prepare the coffee-flavoured drink, the coffee maker  101 , upon having normally been loaded with water and coffee powder, can be placed on the cooker  111  in a manner such as to connect the one-way valve  108  to the connector  114  and the thermometer probe to the electric connector  115 . In order to ease such connections, the cooker  111  could be shaped in a manner such as to allow a correct positioning of the coffee maker. 
     According to this embodiment, upon turning on the coffee machine  100 , e.g., via the switch  116 , all the steps of the method for preparing the coffee-flavoured drink according to the present invention could be automatically performed by the machine itself. 
     In fact, it is provided the option of presetting the maximum temperature to be reached by the water for preparing coffee, e.g., of 90° C., via the adjusting of a thermostat  117 . 
     The signal provided by the thermometer probe  107  is provided to operating means  163 , e.g. an electric or electronic circuit, which will deactivate the heat source  111 . See  FIGS. 9 and 10 . 
     Moreover, upon reaching said temperature, the operating means could activate the gas flow to the inside of the boiler  102 , by means of the connector  114 . 
     In this case, the base  110  could comprise a compressed gas tank, as in the above-described embodiments, operated, e.g., by means of a solenoid valve. 
     Alternatively, the base  110  comprises a micro compressor for air which, once operated, provides compressed air to be introduced in the boiler body. 
     Moreover, the base could provide a pressure and/or flow regulator, adjustable by means of an adjustable control device  118 , in order to set different desired pressure values inside the boiler, depending on the different kinds of coffee used. 
     The present invention has hereto been described with reference to preferred embodiments thereof. Evidently, the three embodiments described hereto could be combined thereamong in a manner such as to originate other embodiments having different combinations of features, without however departing from the inventive kernel of the present invention. 
     In addition, it is understood that other embodiments afferent to the same inventive kernel may exist, all falling within the protective scope of the appended claims.