Abstract:
An espresso coffee dispensing system including at least one espresso coffee production machine including at least one espresso coffee dispensing unit, the unit comprising a filter for containing ground coffee powder and hot water feeder; a coffee grinder having an exit port for coffee powder and a temperature sensor disposed in proximity to the exit port to measure the temperature value of the ground coffee powder leaving the port; electronic controller associated with the coffee grinder to determine the water temperature value.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an espresso coffee dispensing system and method. 
     In particular, the present invention finds application in the professional preparation of espresso coffee in bars, restaurants or the like. 
     BACKGROUND OF THE INVENTION 
     Once roasted and ground, coffee is known to be extremely sensitive to the conditions of the environment in which it is located, in the sense that they can considerably influence the result of the beverage obtained in terms of taste and quality. 
     One of the conditions which mostly influence the beverage quality is the temperature of the ground coffee powder at the moment in which the hot water flow passes through it on preparation. 
     The temperature of the ground coffee powder can firstly vary with varying temperature of the environment in which the coffee grinder operates. 
     Of even greater influence however is the heating effect produced by the grinding itself. In fact, such machines generate on the coffee beans a considerable friction causing the powder to undergo heating. Sometimes the machine action itself can cause overheating of the coffee powder. 
     Examples of known espresso coffee dispensing systems can be seen in WO 2010/085850, DE 20 2009 009496 and EP 1 584 273. 
     The effect of temperature on the coffee powder is reflected in the quality of the beverage obtained. 
     In this respect, it is found that the higher the coffee powder temperature, the more the extraction time (i.e. the time in which a predetermined hot water quantity passes through the coffee powder) decreases. In other words, extraction becomes quicker. 
     This determines less effective extraction of the coffee aromatic components. Moreover, the cream obtained is more unstable, deteriorating rapidly. 
     This causes a further aroma loss from the beverage, as the cream helps to maintain the aromatic substances within the beverage. 
     SUMMARY OF THE INVENTION 
     In this situation, the technical aim at the basis of the present invention is to propose an espresso coffee dispensing system and method which overcome the aforestated drawbacks of the known art. 
     A particular object of the present invention is to provide an espresso coffee dispensing system and method which enable espresso coffee to be prepared of high and constant quality. 
     The stated technical aim and the specified object are substantially attained by an espresso coffee dispensing system and method comprising the technical characteristics stated on one or more of the accompanying claims. 
     Further characteristics and advantages of the present invention will be more apparent from the indicative and therefore non-limiting description of a preferred but non-exclusive embodiment of an espresso coffee dispensing system and method, as illustrated in the accompanying  FIG. 1  which shows a schematic representation of an espresso coffee dispensing system in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows overall an espresso coffee dispensing system according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the accompanying FIGURE ( FIG. 1 ), the reference numeral  1  indicates overall an espresso coffee dispensing system according to the present invention. 
     The system  1  comprises at least one machine  2  for producing espresso coffee. The machine  2  is preferably of the professional type used, for example, in bars, restaurants and the like. 
     The machine  2  comprises at least one espresso coffee dispensing unit  3 . Preferably, the machine  2  comprises a plurality of mutually separate dispensing units  3 . The dispensing units  3  are housed in a single box casing  4  of the machine  2 . 
     Each dispensing unit  3  comprises a filter  5  for containing a predetermined quantity of ground coffee powder and hot water feed means  6  to cause a flow of hot water to pass through the filter  5  in order to prepare the espresso coffee. 
     The feed means  6  comprise a boiler (not shown) for heating the water to a desired temperature and a pump (not shown) for delivering the water at a desired pressure which, typically, is of 9 bar. 
     The feed means  6  of each dispensing unit  3  can be controlled independently of each other. In other words, at least the temperature of the water fed to each dispensing unit  3  can be controlled separately. 
     The system  1  also comprise at least one coffee grinder  7  functionally connected to the machine  2 . Preferably, the system  1  comprises a plurality of coffee grinders  7  for producing ground coffee powder of different types. 
     Each coffee grinder  7  (represented only schematically) comprises a container  8  for containing coffee beans, and grinding wheels  9  for grinding the coffee beans to obtain the coffee powder. A box casing  17  encloses the grinding wheels  9  and the other non-described components. 
     An exit port  10  for the newly ground powder is disposed downstream of the grinding wheels  9 . 
     Preferably, the coffee grinders  7  do not comprise a coffee powder collection tray, hence the coffee grinder  7  delivers only the quantity of coffee powder required to provide the desired beverage at the moment of preparation. 
     Advantageously, the machine  2  and the coffee grinder  7  are separate and are separated from each other. 
     Each coffee grinder  7  also comprises a temperature sensor  11  in a position corresponding with the exit port  10 . 
     The temperature sensors  11  of the coffee grinders  7  generate respective temperature signals “STC” representative of the temperature of the coffee powder leaving the respective exit ports  10 . 
     For example, the temperature sensors  11  can be thermoresistors of PT100 or PT1000 type. Alternatively, the temperature sensors  11  can be of any other suitable type. 
     The system  1  also comprises electronic control means  12  functionally associated with the coffee grinder  7  to receive the respective coffee temperature signals “STC” and functionally associated with the machine  2  to generate respective regulating signals “SR” and send them to the dispensing units  3 . The regulating signals “SR” are representative of the desired water temperature. 
     As will be clearer hereinafter, the regulating signals “SR” are generated on the basis of the coffee temperature signals “STC” arriving from the temperature sensors  11 . 
     Advantageously, the electronic control means  12  comprise a first processor unit  13  disposed inside the machine  2  and a second processor unit  14  disposed inside the coffee grinder  7 . 
     The first  13  and the second processor unit  14  are functionally connected together. 
     For example, the first  13  and the second processor unit  14  are microprocessor units. 
     The electronic control means  12  comprise a comparison element (or subunit)  15  which receives the coffee temperature signals “STC” and compares them with at least one preset reference temperature value. A plurality of different reference values can be set depending on the type of coffee used. 
     The comparison element  15  is preferably disposed in the second processor unit  14 . In alternative embodiments, the comparison element  15  is disposed in the first processor unit  13 . 
     Following the said operation, the comparison element  15  generates corresponding difference signals “SS” which represent the difference between each measured value of the temperature of the coffee leaving the coffee grinder  7  and the reference value. 
     The electronic control means  12  also comprise a regulating element (or subunit)  16  functionally connected to the comparison element  15  to receive the difference signals “SS”. 
     The regulating element  16  is preferably disposed in the first processor unit  13 . In alternative embodiments, the regulating element  16  is disposed in the second processor unit  14 . 
     The regulating element  16  is also functionally connected to the dispensing units  3  to generate a corresponding number of said regulating signals “SR” and send them to said units. In greater detail, the regulating signals “SR” are sent to the hot water feed means  6  such as to set the desired water temperature for each dispensing unit  3 . 
     As stated, each dispensing unit  3  can be controlled independently. Moreover, advantageously, each coffee grinder  7  is functionally associated unequivocally with one or more of the dispensing units  3 . 
     In this manner, water temperature regulation is implemented precisely on that dispensing unit  3  for which the coffee has just been ground. 
     A further temperature sensor  18  is contained inside the box casing  17  of each coffee grinder  7 , preferably distant from the coffee powder exit port  10 . 
     Advantageously, the further temperature sensor  18  is disposed at the second processor unit  14 . 
     Each further temperature sensor  18  generates an internal temperature signal “STI” representative of the temperature value measured in the interior of the compartment of the respective coffee grinder  7 . 
     Each further temperature sensor  18  is functionally associated with the electronic control means  12  to send the respective internal temperature signal “STI” thereto. 
     In this respect, the electronic control means  12  comprise a surveillance element (or subunit)  19  functionally connected to each further temperature sensor  18  to receive the respective internal temperature signal “STI”. 
     The surveillance element  19  is also functionally connected to each further temperature sensor  18  to receive the respective coffee temperature signals “STC”. 
     The surveillance element  19  senses when the measured coffee powder temperature value exceeds a threshold coffee temperature value and at the same time the measured internal temperature value is less than a threshold internal temperature value. 
     In that case the surveillance element  19  generates a maintenance signal “SM” representative of the need to replace the grinding wheels  9  of the coffee grinder  7  in question. This maintenance signal “SM” can be displayed by suitable display means  21 , such as a liquid crystal screen. 
     The surveillance element  19  also generates a ventilation signal “SV” and sends it to a fan  20  inside the box casing  17  of the coffee grinder  7 , to activate it when the measured internal temperature value exceeds the threshold internal temperature value. 
     The invention also provides a method for dispensing espresso coffee. 
     This method comprises the step of grinding a predetermined quantity of coffee. This step is implemented by the coffee grinder  7 . The coffee powder quantity is placed in the filter  5  of the machine  1 . 
     The method also comprises the step of heating a predetermined water quantity to the desired temperature and bringing the water to the desired pressure which, as seen, is preferably  9  bar. These steps are implemented by the feed means  6 . 
     The water is made to pass through the quantity of ground coffee powder, by making it pass through the filter  5 . 
     According to the present invention, the method comprises the step of measuring a ground coffee powder temperature. This step is implemented by the temperature sensor  11 . In particular, the value of the temperature of the powder leaving the coffee grinder  7  is measured. In that case the temperature measurement step and the coffee grinding step are simultaneous. 
     The desired temperature to which to heat the water is determined on the basis of the measured value of the coffee powder temperature. This step is conducted by the electronic control means  12 . 
     In particular, the water temperature determination step is achieved by comparing the measured temperature value with the reference temperature value. In that manner, the difference between the measured temperature value and the reference temperature value is determined. This step is conducted by the comparison element  15  of the electronic control means  12 . 
     Having determined this difference, the value of the water temperature is determined. 
     In particular, a corrective temperature value is determined, to be added to a preset water temperature value. This corrective value is calculated as a function of the value of said difference. 
     This step is conducted by means of the regulating element  16  of the electronic control means  12 . 
     In detail, the corrective temperature value is positive when the difference is negative, whereas it is negative when the difference is positive. 
     As an example, the corrective value is 0.5° C. for each 5° C. of the difference value. 
     In effect, any temperature variation in the ground coffee powder is compensated by modifying the temperature of the water with which the extraction takes place. 
     The invention so described attains the specified purpose. 
     Consequently, the extraction time is maintained constant, hence maintaining the quality of the obtained beverage constant.