Patent Description:
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.

Under constant conditions, a high quality flow meter may be accurate to within. <NUM>%, 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 <NUM> of water and the flow meter is calibrated to deliver. <NUM> per pulse, a controller will simply track the total number of pulses until <NUM> 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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:.

With reference now to <FIG>, a schematic diagram of an example of a basic automatic beverage brewing apparatus <NUM>, such as a coffee maker for example, is illustrated in more detail. The apparatus includes a housing <NUM>, a reservoir <NUM>, a heating mechanism <NUM>, a shower head <NUM>, and a brew basket <NUM>. The reservoir <NUM>, heating mechanism <NUM>, showerhead <NUM>, and brew basket <NUM> are arranged sequentially in fluid communication. Upon activation of the apparatus <NUM>, water or another fluid stored within the reservoir <NUM>, is provided to a heating mechanism <NUM>. After being heated to a desired temperature, the water is provided to the shower head <NUM>. 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 <NUM> via an outlet formed near the bottom of the brew basket.

As illustrated in <FIG>, a flow meter <NUM> may be arranged within a conduit extending between the water reservoir <NUM> and the heating mechanism <NUM>. As shown, the water reservoir <NUM> may be vertically aligned with the flow meter <NUM> such that water is fed to the system <NUM>, and more specifically to the flow meter <NUM>, by gravity. The flow meter <NUM> 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 <NUM>. Various types of flow meters are within the scope of the disclosure. For example, the flow meter <NUM> 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 <NUM>. Further detail on this type of beverage brewing apparatus <NUM> is disclosed in <CIT> and <CIT>. However, it should be understood that the beverage brewing apparatus <NUM> described herein is intended as an example only, and any other apparatus including a flow meter is within the scope of the invention.

With reference now to <FIG>, a software algorithm for dynamically calibrating the flow meter <NUM> based on the operational parameters of the beverage brewing system <NUM>, also referred to herein as "advanced calibration logic", is described in more detail. The brewing apparatus <NUM> 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 <NUM> as advanced calibration logic, the relationship between pulse rate and the calibration variance of the flow meter <NUM> must be identified.

By measuring the actual volume of fluid provided and by monitoring one or more operational parameters of the system <NUM>, a relationship between operation of the flow meter <NUM> and one or more parameters of the system <NUM> may be determined. For example, as shown in Table <NUM> illustrated below, the voltage provided to the flow meter <NUM> and the time required to provide the desired volume of fluid are measured.

In the illustrated, non-limiting embodiment, the programmed volume of fluid to be provided was <NUM>. As shown in the table above, the difference between the programmed volume and the measured volume was between -<NUM>% and <NUM>% for each of the various test runs. Through this experimentation, it has been determined that the accuracy of the flow meter <NUM> fluctuates with the flow rate when the voltage applied to the system <NUM> is varied. A graph comparing the flow rate (mL/s) and Volume Variation of the data of Table <NUM> is illustrated in <FIG>.

During operation, the system <NUM> is only configured to observe pulses generated by the flow meter <NUM> and has no knowledge of flow rate. <FIG> 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 <NUM> 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 <NUM> pulse section of the graph of <FIG> is shown in Table <NUM> below.

By analyzing this data relative to voltage and temperature ranges, two graphs, shown in <FIG> and <FIG>, were generated to identify the relationship between flow rate and calibration variance (<FIG>), as well as pulse rate and calibration variance (<FIG>). 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 <NUM> is rotating.

The relationship presented in <FIG> directly correlates a signal sent from the flow meter <NUM> and received by a controller of the brewing system <NUM> with a calibration variation. As a result, the calibration coefficient can be used to determine a total volume delivered by the flow meter <NUM> with each pulse. In this embodiment, for every pulse fewer recorded per <NUM>-second averaging window, the calibration would increase by <NUM>% 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 <NUM> milliliters of fluid per pulse under nominal conditions. If a pulse were to exist whereby the average number of pulses recorded in a <NUM>-second window was <NUM>, the scaling factor would thus be calculated as: <MAT> This pulse, therefore, would have a delivery volume of <NUM> milliliters * <NUM> = <NUM> millilters, which is then added to the total volume delivered. This scaling factor is applied to every pulse observed by the flow meter <NUM> until the total volume delivered has reached a prescribed target volume, in this embodiment <NUM>.

This scaling factor can be applied to a recorded data set to more accurately predict the volume of fluid delivered by a flow meter <NUM>. For example, the graph of <FIG> compares the volume of fluid delivered by a flow meter <NUM> using the fixed calibration logic, and the volume of fluid delivered by a flow meter <NUM> using the scaling factor of the advanced calibration logic relative to a target volume. As is clearly illustrated, the flow meter <NUM> using the advanced calibration logic is substantially more accurate relative to the target volume.

Because both of the graphs in <FIG> and <FIG> 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>. This relationship enables an average pulse rate to be approximated for test runs on where only volume and time were recorded.

The data illustrated in Tables <NUM> and <NUM> and <FIG> is representative of a single beverage brewing apparatus <NUM>. Although each unit of a mass produced beverage brewing apparatus <NUM> 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 <NUM>, similar experimentation is performed using a plurality of units of the beverage brewing apparatus <NUM> to create an approximation of the average pulse rates based on average flow rates thereof, as shown in <FIG>.

By applying similar transformations to the data collected from a plurality of units, for example <NUM> units, it was determined that although a spread in performance exists, most of the units followed a predictable trend illustrated in <FIG>, 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 <NUM> may drastically increase as the power to the system varies. It is also observed that a nominal calibration coefficient is centered about <NUM> 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 <NUM> 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 <NUM>-<NUM>. Under these conditions, the average pulse count is approximately <NUM> pulses per <NUM> seconds. By adjusting the equation of the linear regression line of <FIG> to account for this shift in the average conditions, the resultant dynamic flow meter calibration scaling value is: <MAT>.

Application of this scaling value to the flow meter calibration coefficient allows the volume of fluid measured by the flow meter <NUM> to adjust dynamically during operation of the apparatus <NUM> to such that a more accurate amount of water is consistently provided for brewing a beverage.

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 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.

Claim 1:
A beverage brewing apparatus, comprising:
a reservoir;
a brew basket configured to contain a flavorant for preparing a brewed beverage;
a heating mechanism fluidly coupled to the reservoir and the brew basket; and
a flow meter configured to produce pulses, at a pulse rate, to measure a volume of fluid supplied from the reservoir to said brew basket, each pulse representing a nominal volume of said fluid passing through the flow meter; characterized in that
the apparatus is configured to calibrate the flow meter dynamically during operation of the apparatus, in response to at least one operating parameter of the apparatus, by applying a scaling factor to adjust the nominal volume represented by each pulse, wherein the scaling factor is based on an identified relationship between calibration variance and pulse rate of the flow meter.