Abstract:
A beverage brewing apparatus is provided including a reservoir, a brew basket configured to container a flavorant for preparing a brewed beverage, and a heating mechanism fluidly coupled to the reservoir and the brew basket. A flow meter is configured to measure a volume of fluid supplied from the reservoir to the brew bask. The flow meter is configured to calibrate dynamically in response to at least one operating parameter of the beverage brewing apparatus.

Description:
BACKGROUND 
       [0001]    This application relates to a flow meter, and more specifically to dynamic calibration of a flow meter of a beverage brewing apparatus. 
         [0002]    A plurality of factors influence the flavor when brewing a cup of coffee, including the quantity of coffee, the quantity of water, the temperature of the water, and the contact time between the coffee and the water. In many systems configured to brew a beverage such as coffee, a flow meter is used to monitor a volume of water delivered to the coffee. The flow meter generally includes a rotor having opposing polarity magnets embedded therein. The rotor is configured to spin about a central axis as water flows there through. As the flow meter rotates, these magnets pass a Hall Effect sensor, functioning as a switch that it activated and deactivated by the magnetic fields of the magnets. For every rotation of the rotor, a high and low signal is observed by the Hall Effect sensor. 
         [0003]    Under constant conditions, a high quality flow meter may be accurate to within 0.5%, meaning that each toggle in the flow meter signal can be related directly to a volume of water. For example, if a system intends to deliver 1000 mL of water and the flow meter is calibrated to deliver 0.5 mL per pulse, a controller will simply track the total number of pulses until 2000 pulses have been observed. Accuracy of these systems is dependent upon the linearity of the flow meter over the operating range of the system. In order to control the operation conditions of a beverage brewing system a pump is typically used to control the flow rate. However, in systems where the operating conditions are not controlled, the flow rate of fluid through the flow meter may change based on variates in the wall voltage, boiler power, boiler efficiency, water temperature, or other influencing factors. As these factors shift the flow rate away from the nominal target rate, the performance of the flow meter similarly shifts, thereby compromising the accuracy of the system. 
       SUMMARY 
       [0004]    According to one embodiment, a beverage brewing apparatus is provided including a reservoir, a brew basket configured to container a flavorant for preparing a brewed beverage, and a heating mechanism fluidly coupled to the reservoir and the brew basket. A flow meter is configured to measure a volume of fluid supplied from the reservoir to the brew bask. The flow meter is configured to calibrate dynamically in response to at least one operating parameter of the beverage brewing apparatus. 
         [0005]    In addition to one or more of the features described above, or as an alternative, in further embodiments the at least one operating parameter includes voltage of the beverage system. 
         [0006]    In addition to one or more of the features described above, or as an alternative, in further embodiments the at least one operating parameter includes a temperature of the fluid. 
         [0007]    According to another embodiment, a method of dynamically calibrating a flow meter is provided including identifying a relationship between calibration variance and pulse rate of the flow meter to form an advanced logic calibration and applying the advanced logic calibration to the flow meter. 
         [0008]    In addition to one or more of the features described above, or as an alternative, in further embodiments the advanced logic calibration is applied to each pulse observed by the flow meter. 
         [0009]    In addition to one or more of the features described above, or as an alternative, in further embodiments the relationship between calibration variance and pulse rate is generally linear. 
         [0010]    In addition to one or more of the features described above, or as an alternative, in further embodiments the relationship between calibration variance and pulse rate of the flow meter is determined using data collected during operation of a beverage brewing apparatus. 
         [0011]    In addition to one or more of the features described above, or as an alternative, in further embodiments the advanced calibration logic is based on data collected from a plurality of beverage brewing apparatuses. 
         [0012]    In addition to one or more of the features described above, or as an alternative, in further embodiments the method includes identifying a relationship between calibration variance and flow rate of a fluid through the flow meter to form an advanced logic calibration. A relationship between between flow rate and pulse rate is then determined. 
         [0013]    In addition to one or more of the features described above, or as an alternative, in further embodiments an average pulse rate per time interval is calculated for the plurality of beverage brewing apparatuses. The advanced logic calibration is then applied to the average pulse rate. 
         [0014]    In addition to one or more of the features described above, or as an alternative, in further embodiments an operating condition of at least one of the plurality of beverage brewing apparatuses is different. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0015]    The accompanying drawings incorporated in and forming a part of the specification embodies several aspects of the present disclosure and, together with the description, serves to explain the principles of the disclosure. In the drawings: 
           [0016]      FIG. 1  is a schematic diagram of an example of a beverage brewing apparatus; 
           [0017]      FIG. 2  is a graph comparing flow rate and volumetric variation measured for a single beverage brewing apparatus; 
           [0018]      FIG. 3  is a graph illustrating the pulses of a flow meter over a set period of time for a single beverage brewing apparatus; 
           [0019]      FIG. 4  is a graph comparing flow rate and calibration variation measured for a single beverage brewing apparatus; 
           [0020]      FIG. 5  is a graph comparing pulse rate and calibration variation measured for a single beverage brewing apparatus 
           [0021]      FIG. 6  is a graph comparing flow rate and pulse rate based on the measured data of a single beverage brewing apparatus; 
           [0022]      FIG. 7  is a graph representing a volume of fluid delivered by a flow meter having fixed logic and a flow meter having advanced calibration logic compared to a target volume; and 
           [0023]      FIG. 8  is a graph comparing pulse rate to the volume variance for a plurality of beverage brewing apparatuses having varying operational parameters. 
       
    
    
       [0024]    The detailed description explains embodiments of the disclosure, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION 
       [0025]    With reference now to  FIG. 1 , a schematic diagram of an example of a basic automatic beverage brewing apparatus  20 , such as a coffee maker for example, is illustrated in more detail. The apparatus includes a housing  22 , a reservoir  24 , a heating mechanism  26 , a shower head  28 , and a brew basket  30 . The reservoir  24 , heating mechanism  26 , showerhead  28 , and brew basket  30  are arranged sequentially in fluid communication. Upon activation of the apparatus  20 , water or another fluid stored within the reservoir  30 , is provided to a heating mechanism  26 . After being heated to a desired temperature, the water is provided to the shower head  28 . The shower head is aligned with and disposed vertically above the brew basket. The water is configured to flow through one or more holes formed in the shower head onto coffee grounds or another flavorant contained within the brew basket. The fluid containing a portion of the flavorant, is provided to a container  31  via an outlet formed near the bottom of the brew basket. 
         [0026]    As illustrated in  FIG. 1 , a flow meter  32  may be arranged within a conduit extending between the water reservoir  24  and the heating mechanism  26 . As shown, the water reservoir  24  may be vertically aligned with the flow meter  32  such that water is fed to the system  20 , and more specifically to the flow meter  32 , by gravity. The flow meter  32  is configured to monitor an amount of water passing there through, which is generally indicative of the amount of water provided to the shower head  28 . Various types of flow meters are within the scope of the disclosure. For example, the flow meter  32  may be a rotatable paddle wheel where each rotation generates a signal indicating that a known amount of water has passed through the flow meter  92 . Further detail on this type of beverage brewing apparatus  20  is disclosed in U.S. patent application Ser. No. 14/568,471 filed on Dec. 12, 2014 and U.S. patent application Ser. No. 14/812,731 filed on Jul. 29, 2015, the contents of both of which are incorporated herein by reference. However, it should be understood that the beverage brewing apparatus  20  described herein is intended as an example only, and any other apparatus including a flow meter is within the scope of the invention. 
         [0027]    With reference now to  FIGS. 2-8 , a software algorithm for dynamically calibrating the flow meter  32  based on the operational parameters of the beverage brewing system  20 , also referred to herein as “advanced calibration logic”, is described in more detail. The brewing apparatus  20  is configured to provide a known volume of fluid when operated in a first mode. To generate an equation to be applied to operation of the flow meter  32  as advanced calibration logic, the relationship between pulse rate and the calibration variance of the flow meter  32  must be identified. 
         [0028]    By measuring the actual volume of fluid provided and by monitoring one or more operational parameters of the system  20 , a relationship between operation of the flow meter  32  and one or more parameters of the system  20  may be determined. For example, as shown in Table 1 illustrated below, the voltage provided to the flow meter  32  and the time required to provide the desired volume of fluid are measured. 
         [0000]    
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Recorded Measurements from Test Unit 1 
               
             
          
           
               
                   
                 Volume 
                 vs. 
                 Effective 
                 Flow 
               
               
                 Voltage 
                 Delivered 
                 Target 
                 Time (s) 
                 Rate 
               
               
                   
               
             
          
           
               
                 128 
                 1267 
                 −1.1% 
                 305 
                 4.15 
               
               
                 128 
                 1259 
                 −1.7% 
                 303 
                 4.16 
               
               
                 120 
                 1294 
                 1.0% 
                 340 
                 3.81 
               
               
                 120 
                 1291 
                 0.8% 
                 337 
                 3.83 
               
               
                 112 
                 1310 
                 2.3% 
                 382 
                 3.43 
               
               
                 112 
                 1323 
                 3.3% 
                 386 
                 3.43 
               
               
                 104 
                 1351 
                 5.5% 
                 447 
                 3.02 
               
               
                 104 
                 1348 
                 5.2% 
                 451 
                 2.99 
               
               
                   
               
             
          
         
       
     
         [0029]    In the illustrated, non-limiting embodiment, the programmed volume of fluid to be provided was 1281 mL. As shown in the table above, the difference between the programmed volume and the measured volume was between −1.7% and 5.5% for each of the various test runs. Through this experimentation, it has been determined that the accuracy of the flow meter  32  fluctuates with the flow rate when the voltage applied to the system  20  is varied. A graph comparing the flow rate (mL/s) and Volume Variation of the data of Table 1 is illustrated in  FIG. 2 . 
         [0030]    During operation, the system  20  is only configured to observe pulses generated by the flow meter  32  and has no knowledge of flow rate.  FIG. 3  indicates the recorded pulse rates on a moving average basis, or more specifically, the number of pulses recorded in a set time period. Although a time period of 2 seconds was used in the illustrated, non-limiting embodiment, any length of time sufficient to provide an accurate representation of the data with a minimized delay is acceptable. Using this pulse information, the average flow rate can be tracked and converted into a calibration scaling factor. An example of the data recorded for a 50 pulse section of the graph of  FIG. 3  is shown in Table 2 below. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Time Array of recorded pulses 
               
             
          
           
               
                   
                 Array 
                 Pulse 
               
               
                   
                 Element 
                 Time 
               
               
                   
                   
               
             
          
           
               
                   
                 0 
                 8801 
               
               
                   
                 1 
                 8966 
               
               
                   
                 2 
                 9086 
               
               
                   
                 3 
                 9225 
               
               
                   
                 4 
                 9329 
               
               
                   
                 5 
                 9444 
               
               
                   
                 6 
                 9542 
               
               
                   
                 7 
                 9642 
               
               
                   
                 8 
                 9744 
               
               
                   
                 9 
                 9851 
               
               
                   
                 10 
                 9946 
               
               
                   
                 11 
                 10053 
               
               
                   
                 12 
                 10160 
               
               
                   
                 13 
                 10284 
               
               
                   
                 14 
                 10391 
               
               
                   
                 15 
                 10501 
               
               
                   
                 16 
                 10604 
               
               
                   
                 17 
                 10705 
               
               
                   
                 18 
                 10800 
               
               
                   
                 19 
                 10904 
               
               
                   
                 20 
                 11001 
               
               
                   
                 21 
                 11109 
               
               
                   
                 22 
                 11209 
               
               
                   
                 23 
                 11321 
               
               
                   
                 24 
                 11427 
               
               
                   
                 25 
                 5252 
               
               
                   
                 26 
                 5335 
               
               
                   
                 27 
                 5428 
               
               
                   
                 28 
                 5514 
               
               
                   
                 29 
                 5611 
               
               
                   
                 30 
                 5703 
               
               
                   
                 31 
                 5805 
               
               
                   
                 32 
                 5901 
               
               
                   
                 33 
                 6008 
               
               
                   
                 34 
                 6111 
               
               
                   
                 35 
                 6226 
               
               
                   
                 36 
                 6338 
               
               
                   
                 37 
                 6463 
               
               
                   
                 38 
                 6584 
               
               
                   
                 39 
                 6720 
               
               
                   
                 40 
                 6852 
               
               
                   
                 41 
                 7008 
               
               
                   
                 42 
                 7164 
               
               
                   
                 43 
                 7362 
               
               
                   
                 44 
                 7581 
               
               
                   
                 45 
                 7864 
               
               
                   
                 46 
                 8115 
               
               
                   
                 47 
                 8337 
               
               
                   
                 48 
                 8513 
               
               
                   
                 49 
                 8665 
               
               
                   
                   
               
             
          
         
       
     
         [0031]    By analyzing this data relative to voltage and temperature ranges, two graphs, shown in  FIGS. 4 and 5 , were generated to identify the relationship between flow rate and calibration variance ( FIG. 4 ), as well as pulse rate and calibration variance ( FIG. 5 ). The graph of pulse rate vs. calibration variance is configured to indicate the variation in the calibration coefficient based on how fast the flow meter  32  is rotating. 
         [0032]    The relationship presented in  FIG. 5  directly correlates a signal sent from the flow meter  32  and received by a controller of the brewing system  20  with a calibration variation. As a result, the calibration coefficient can be used to determine a total volume delivered by the flow meter  32  with each pulse. In this embodiment, for every pulse fewer recorded per 2-second averaging window, the calibration would increase by 2.64% as noted by the linear regression through the data set. In this embodiment, the nominal calibration coefficient, corresponding to a volume of water passing through the flow meter, was specified to be 0.656 milliliters of fluid per pulse under nominal conditions. If a pulse were to exist whereby the average number of pulses recorded in a 2-second window was 10.0, the scaling factor would thus be calculated as: 
         [0000]      Scaling Factor=−0.0264*(10.0)+1.3751=1.111
 
         [0000]    This pulse, therefore, would have a delivery volume of 0.656 milliliters*1.111=0.7288 milliliters, which is then added to the total volume delivered. This scaling factor is applied to every pulse observed by the flow meter  32  until the total volume delivered has reached a prescribed target volume, in this embodiment 1281 mL. 
         [0033]    This scaling factor can be applied to a recorded data set to more accurately predict the volume of fluid delivered by a flow meter  32 . For example, the graph of  FIG. 7  compares the volume of fluid delivered by a flow meter  32  using the fixed calibration logic, and the volume of fluid delivered by a flow meter  32  using the scaling factor of the advanced calibration logic relative to a target volume. As is clearly illustrated, the flow meter  32  using the advanced calibration logic is substantially more accurate relative to the target volume. 
         [0034]    Because both of the graphs in  FIGS. 4 and 5  compare calibration variance, a relationship between the flow rate and the average pulse rate may be established. A graph illustrating the relationship between the average flow rate and the average pulse rate is illustrated in  FIG. 6 . This relationship enables an average pulse rate to be approximated for test runs on where only volume and time were recorded. 
         [0035]    The data illustrated in Tables 1 and 2 and  FIGS. 2-7  is representative of a single beverage brewing apparatus  20 . Although each unit of a mass produced beverage brewing apparatus  20  is formed substantially identically, differences in performance may occur due to variances in manufacturing, assembly, or usage conditions. To create a universal calibration coefficient applicable to all of the units of a mass produced beverage brewing apparatus  20 , similar experimentation is performed using a plurality of units of the beverage brewing apparatus  20  to create an approximation of the average pulse rates based on average flow rates thereof, as shown in  FIG. 6 . 
         [0036]    By applying similar transformations to the data collected from a plurality of units, for example 14 units, it was determined that although a spread in performance exists, most of the units followed a predictable trend illustrated in  FIG. 8 .  FIG. 8 , which compares average pulse rate to volumetric variance, clearly shows that in the absence of advanced calibration logic, the volume of water delivered via a flow meter  32  may drastically increase as the power to the system varies. It is also observed that a nominal calibration coefficient is centered about 13.4 average pulses, which corresponds to room temperature water being brewed using 120V of power. However, because the voltage range provided across the United States extends from between 107V to 128V and because most brewing apparatuses  20  instruct an operator to use cold water, it is desirable to set the neutral point of operation at averaged conditions assuming a power supply of 117V and a cold water temperature of about 3-5° C. Under these conditions, the average pulse count is approximately 10.2 pulses per 2 seconds. By adjusting the equation of the linear regression line of  FIG. 8  to account for this shift in the average conditions, the resultant dynamic flow meter calibration scaling value is: 
         [0000]      Scaling Value=−0.012305* n   pulses +1.25508
 
         [0037]    Application of this scaling value to the flow meter calibration coefficient allows the volume of fluid measured by the flow meter  32  to adjust dynamically during operation of the apparatus  20  to such that a more accurate amount of water is consistently provided for brewing a beverage. 
         [0038]    All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
         [0039]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure. 
         [0040]    Exemplary embodiments of this disclosure are described herein, including the best mode known to the inventors for carrying out the disclosure. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the disclosure to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.