Liquid presence determination in beverage machine

Abstract

Methods and systems for employing a sensor to detect whether a liquid is present in a beverage machine. A sensor may have a controller to apply alternating current (AC) excitation pulses to one of two probes disposed in the beverage machine. The sensor may also have a detector to obtain voltage measurements used to determine a presence of liquid.

Description

LIQUID PRESENCE DETERMINATION IN BEVERAGE MACHINEFIELD

[0001] This disclosure relates to beverage machines, such as coffee brewers that use a liquid to form the beverage.BACKGROUND

[0002] Beverage machines frequently employ a temperature sensor to detect a temperature of water or other liquid, e.g., to help ensure that the liquid is suitably heated, cooled or otherwise at a desired temperature for beverage formation. As an example, some coffee brewers use a temperature sensor positioned to contact liquid in a heater tank to detect the temperature of liquid in the tank and to control a heater accordingly.SUMMARY

[0003] According to one aspect, a beverage machine is provided. The beverage machine may include a liquid supply tank to provide liquid for use in forming a beverage. The liquid supply tank may have an internal volume with a floor. A conduit may receive liquid from the liquid supply tank. The conduit may be external to the internal volume of the liquid supply tank. A sensor may detect a presence of liquid in the conduit. The sensor may include probes located within the conduit and at a height within the conduit that is above the floor of the liquid supply tank. A controller may provide an excitation signal based on an alternating current (AC) or a pulsating excitation signal to the probes. Voltage at at least one of the probes resulting from a cycle of the AC excitation signal or pulsating excitation signal may be used to determine the presence of liquid in the conduit.

[0004] A method of sensing liquid in a beverage machine may include applying an excitation signal based on an alternating current (AC) or a pulsating excitation signal to a first probe located in the beverage machine. The method may also include obtaining voltage measurements from the first probe to detect voltage values between the first probe and a second probe in the machine. The voltage values result from application of a cycle of the AC excitation signal or pulsating excitation signal, and two or more of the voltage values may be used to determine a presence of the liquid.

[0005] A system in a beverage machine may include probes disposed in the beverage machine, and a controller to apply an excitation signal based on an alternating current (AC) or a pulsatingexcitation signal to the probes. A detector may obtain first and second voltage measurements indicating respective first and second voltage values between the probes resulting from application of a cycle of the AC excitation signal or pulsating excitation signal. The first and second voltage values may be used to determine a presence of water.

[0006] These and other aspects of the disclosure will be apparent from the following description and claims. It should be appreciated that the foregoing concepts, and additional concepts discussed below, may be arranged in any suitable combination, as the present disclosure is not limited in this respect. Further, other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments when considered in conjunction with the accompanying figures.BRIEF DESCRIPTION OF DRAWINGS

[0007] In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0008] FIG. 1 is a perspective view of a beverage machine in an illustrative embodiment;

[0009] FIG. 2 is schematic diagram of selected components of the beverage machine in an illustrative embodiment;

[0010] FIG. 3 is a circuit diagram of an exemplary sensor arrangement that can be employed in a beverage machine;

[0011] FIG. 4 is a circuit diagram of another exemplary sensor arrangement that can be employed in a beverage machine; and

[0012] FIG. 5 is a circuit diagram of another exemplary sensor arrangement that can be employed in a beverage machine.DETAILED DESCRIPTION

[0013] It should be understood that aspects of the disclosure are described herein with reference to certain illustrative embodiments and the figures. The illustrative embodiments described herein are not necessarily intended to show all aspects of the disclosure, but rather are used to describe a few illustrative embodiments. Thus, aspects of the disclosure are not intended to be construed narrowly in view of the illustrative embodiments. In addition, aspects of the disclosure may be used alone or in any suitable combination with other aspects of the disclosure.

[0014] Generally speaking, a beverage machine may be used to form any suitable beverage, such as tea, coffee, other infusion-type beverages, beverages formed from a liquid or powderedconcentrate, soups, juices or other beverages made from dried materials, carbonated or uncarbonated beverages. The beverage machine can form such beverages using a base liquid, such as water (e.g., demineralized water, tap water, bottled water), stored in a liquid supply tank. A beverage machine can be capable of forming a variety of beverages, each requiring a different amount of the base liquid. Thus, it may be desirable for a beverage machine to include features that allow the beverage machine to detect one or more physical characteristics of the liquid, e.g., detect a liquid level in the liquid supply tank, detect that liquid is available for use and / or is being provided to the machine components, detect a temperature of the liquid, etc. As discussed in more detail below, in some embodiments, a beverage machine can include a sensor that detects a presence or absence of the liquid. In addition, aspects of the detection technique may allow different types of liquid, including demineralized water, to be detected.

[0015] FIG. 1 shows a perspective view of a beverage machine 100 that incorporates features of this disclosure. In this illustrative embodiment, the machine 100 is arranged to form coffee or tea beverages. As is known in the art, a beverage cartridge 1 may be provided to the system 100 and used to form a beverage that is deposited into a user’s cup or other suitable container 2. The cartridge 1 may be manually or automatically placed in a brew chamber of a beverage dispensing station 15 that in some embodiments includes a cartridge holder 3 and cover 4 of the beverage machine 100. For example, the holder 3 may be or include a circular, cup-shaped or otherwise suitably shaped opening in which the cartridge 1 may be placed. With a cartridge 1 placed in the cartridge holder 3, a handle 5 may be moved by hand (e.g., downwardly) so as to move the cover 4 to a closed position (as shown in FIG. 1). In the closed position, the cover 4 at least partially covers the cartridge 1 , which is at least partially enclosed in a space in which the cartridge 1 is used to make a beverage. For example, with the cartridge 1 held by the cartridge holder 3 in the closed position, water or other liquid may be provided to the cartridge 1 (e.g., by injecting the liquid into the cartridge interior) to form a beverage that exits the cartridge 1 and is provided to a cup 2 or other container. Of course, aspects of the disclosure may be employed with any suitably arranged system 100, including drip-type coffee brewers, carbonated beverage machines, and other systems that deliver water or other liquid to form a beverage. Thus, a cartridge 1 need not necessarily be used, but instead the beverage dispensing station 15 can accept loose coffee grounds or other beverage material to make a beverage. Also, the dispensing station 15 need not necessarily include a cartridge holder 3 and a cover 4. For example, dispensing station 15 can include a filter basket that is accessible to provide beverage material (such as loose coffee grounds), and the filter basket itself may be movable, e.g., by slidingengagement with the beverage machine housing 10, and a cover 4 may be fixed in place. In other embodiments, the dispensing station 15 need not be user accessible but, instead, beverage material may be automatically provided to, and removed from, the dispensing station 15. Moreover, the system 100 need not have a brew chamber but, instead, other types of dispensing stations, e.g., that dispense hot and / or cold water (whether still or carbonated) at an outlet such as a dispensing nozzle without mixing with any beverage ingredient. Accordingly, a wide variety of different types and configurations for a dispensing station may be employed with aspects of this disclosure.

[0016] In some embodiments, the beverage machine 100 uses liquid, such as water, that is provided by a liquid supply 6 to form a beverage. In some embodiments, the liquid supply 6 can include a tank 61 arranged to hold water or other liquid. The tank 61 can be removably supported on a base 62, which fluidly couples to a port on a bottom of the tank 61 to receive and deliver liquid to other components of the machine 100, such as the dispensing station 15. The floor 60 of the tank 61 is indicated above the base 62 in FIG. 2. A removable tank 61 can be convenient for a user because the user can remove the tank 61 from the base 62, e.g., by grasping a handle on the tank 61, for filling and then replace the tank 61 on the base 62. This is just one example, however, and a machine 100 can receive and / or store liquid in other ways. For example, the machine 100 can have a connection to a mains water supply (e.g., so-called “city water” or a line that delivers water under pressure to the machine 100), can have an internal or non-removable liquid supply tank or reservoir, or other suitable arrangement.

[0017] In some embodiments, the machine 100 has one or more sensor components, and some of those components may detect characteristics of liquid in the liquid supply 6. As an example, the machine 100 can include a sensor component that contacts liquid in the liquid supply 6 to detect a presence or absence of liquid (e.g., to indicate a low water level in the tank 61), a temperature of water received from the tank 61, and / or other physical characteristics of the liquid. Such sensor components can be part of a sensor circuit that is electrically powered and used by a machine controller to detect the physical characteristics of the liquid and control the machine 100 accordingly. As an example, a controller can use a low water signal from a sensor circuit to provide an indication to a user that water needs to be added to the tank 61 and / or use a temperature signal from a sensor circuit to control a heater or other liquid conditioner (such as a chiller, carbonator, etc.).

[0018] In some embodiments, for example, the beverage machine 100 can have a sensor component arranged to detect physical characteristics of the liquid in a supply line, such as the presence or absence of the liquid and / or a temperature of the liquid.

[0019] FIG. 2 shows a schematic diagram of selected beverage machine 100 components in one embodiment that employs a sensor 9 that includes sensor components 91, 92 arranged to detect at least one physical characteristic of liquid in the liquid supply 6. In one example, the sensor component 91 may include conductive component arranged to contact liquid in the supply line 63 and may also include a temperature component arranged to detect a temperature of liquid in a supply line 63. Thus, in some arrangements, the sensor component 91 can include a first conductive probe having an electrically conductive portion in contact with the liquid to detect a first physical characteristic of the liquid (e.g., to detect a presence and absence of the liquid), and a temperature probe that is electrically insulated from the liquid and arranged to detect a second physical characteristic of the liquid (e.g., the temperature probe such as a thermistor arranged to detect temperature of the liquid). The first conductive probe of the sensor component 91 may work in conjunction with the sensor component 92, which may include a second conductive probe, as discussed. The sensor component 92 may, additionally or alternately to the sensor component 91, also include a temperature probe.

[0020] In some embodiments, the supply line 63 is fluidly coupled to the tank 61 (e.g., via a port at a bottom of the tank 61) and arranged to deliver liquid to a pump 12. The pump 12 can have an inlet fluidly coupled to the supply line 63 to receive liquid from the tank 61, and can deliver the liquid via an outlet to a heater 13 (or other liquid conditioner such as a chiller, carbonator, etc. that is fluidly coupled to the pump outlet), which heats (cools, carbonates, etc.) the liquid that is subsequently delivered to the dispensing station 15. In FIG. 2, the sensor component 91 is shown between the tank 61 and the pump 12, but the sensor (or other additional sensors) can be located in other places, such as between the pump 12 and heater 13, for example. The second sensor component 92 is shown upstream of the heater 13, but may also be located in other places. The sensor components 91, 92 may be located anywhere along the liquid supply conduit (between the tank 61 and dispensing station 15). Thus, generally at least one of the sensor components 91, 92 are at a height above the floor 60 of the tank 61.

[0021] In some embodiments, the sensor components 91, 92 and specifically, the first conductive probe and the second conductive probe can detect the presence or absence of liquid in the supply line 63, as detailed with reference to FIGs. 3-5. If the sensor component 91 and / or the sensor component 92 includes a temperature probe or a pressure sensor, detecting thepresence of liquid may provide an indication that another physical characteristic detected by the sensor component 91, 92 (such as a temperature or pressure) is associated with the liquid rather than some other item. This can be useful, for example, where the sensor 9 is located in a part of the liquid supply 6 where liquid is not always present, and / or where the sensor 9 detects another characteristic, such as temperature, that is used to control operation of a pump 12 and / or heater 13. In addition, the presence / absence of liquid determined and signaled by the sensor 9 can provide an indication that the tank 61 is disconnected from the machine 100, has an exhausted liquid supply and / or that a liquid level in the tank 61 is below a threshold level. In the arrangement of FIG. 2, the supply line 63 is fluidly coupled to the bottom of the tank 61 and extends upwardly, e.g., above a maximum liquid level ML of the tank 61.

[0022] Since the sensor components 91, 92 are arranged in the supply line 63 and the path from the heater 13 to the dispensing station 15, this can allow the sensor 9 to detect whether liquid is present at least between the sensor components 91, 92.

[0023] In some cases, the sensor 9 can detect whether a liquid level LL of liquid in the supply line 63 is above or below a location of the sensor component 91 along the supply line 63. This can allow a determination of whether a liquid level LL in the tank 61 is below a threshold level, such as a minimum level required to dispense a beverage. In some embodiments, the supply line 63 can include a vent 64 arranged to vent the supply line 63 to atmospheric or other ambient pressure, e.g., the vent 64 can include an electrically-operated valve that a controller 16 can open to expose the supply line 63 to ambient pressure. In some cases, the vent 64 can be positioned above the maximum liquid level ML and / or above a position of the sensor component 91. Venting of the supply line 63 can allow the liquid level in the supply line 63 to correspond to, or be the same as, the liquid level LL in the tank 61. Thus, if the supply line 63 is vented and the sensor 9 detects the presence of liquid, the controller 16 can determine that the liquid level LL in the tank 61 is above the position or height of the sensor component 91 (e.g., above a threshold level), and if the sensor 9 does not detect the presence of liquid (i.e., detects the absence of liquid), the controller 16 can determine that the liquid level LL in the tank 61 is below the position or height of the sensor component 91 or that the tank 61 is disconnected from the supply line 63. In some embodiments, the beverage machine need not include a valve for the vent 64. For example, the vent 64 can have a permanently open orifice or other opening of suitable size to always vent the supply line 63 to atmosphere. The vent 64 opening sized can be arranged relative to the pump capacity such that the pump can deliver liquid for beverage formation even though air may be drawn into the vent 64.

[0024] In some embodiments, the pump 12 is located at or above the maximum liquid level ML of the tank 61 or at least downstream of the location of the sensor component 91 along the supply line 63. This arrangement can allow a determination whether liquid is being supplied to the pump 12 or not and can be useful to determine whether the tank 61 is disconnected from the machine 100 and / or a liquid supply in the tank 61 has been exhausted. For example, if the tank 61 is removed from the base 62 or runs out of liquid during operation of the pump 12 in drawing liquid from the tank 61, air will be drawn into the supply line 63 rather than liquid. When air reaches the sensor component 91, the sensor 9 can detect the absence of liquid and thus that the tank 61 has been removed or the liquid supply exhausted.

[0025] As will be understood from the above, the sensor components 91, 92 of the sensor 9 can be positioned in a liquid supply 6 in a location where liquid may not always be present between the first and second conductive probes, e.g., whether upstream or downstream of the pump 12 and / or in other locations. Thus, where the sensor 9 can detect the presence / absence of liquid and any other characteristics of the liquid such as temperature or pressure, the sensor 9 can provide the controller 16 with information regarding not only whether liquid is present or absent, but also whether the other detected characteristic is properly associated with the liquid or not. For example, if no liquid is detected by the sensor 9, then a detected temperature by the sensor component 91 may not be of the liquid, but rather of the supply line 63, air or other item. The controller 16 can use signals from the sensor 9 regarding detected characteristics to control at least a portion of the beverage machine. As an example, the controller 16 may normally use liquid temperature sensed by the sensor component 91 to control a heater 13, such as an inline heater or flash heater. Such inline heaters heat liquid relatively rapidly as the liquid passes through the heater 13, and so the incoming temperature of liquid can be useful to control a heating rate, output power or other characteristics of the heater 13 and / or to control a flow rate of liquid delivered by the pump 12 to the heater 13. As an example, colder incoming water may require use of a higher heating rate or power and / or a lower liquid flow rate than warmer incoming water.

[0026] Where the sensor component 91 is positioned upstream of the heater 13, the controller 16 can determine whether a sensed temperature is indicative of liquid delivered to the heater 13 or not, and this information can be used to control the heater 13, the pump 12 and / or other components. For example, in some embodiments, the controller 16 can be arranged to control the vent 64 and pump 12 to deliver air to the heater 13 so that the air can be heated and delivered to dispensing station 15 (e.g., to pre-heat the station 15 prior to dispensing a hot beverage. Thiscan be done by opening the vent 64 and operating the pump 12 so only air is pumped to the heater 13 and dispensing station 15.). Heating air may require a lower heating rate or output power than heating water and so the controller 16 may control the heater accordingly.

[0027] Subsequently, the controller 16 can control the vent 64 and pump 12 to deliver liquid from the tank 61 to the heater 13 for heating and delivery to the dispensing station 15 (e.g., by closing the vent 64 and operating the pump 12 to draw liquid from the tank 61 and deliver the liquid to the heater 13). The sensor component 91, which may be positioned between the vent 64 and the pump 12 or between the pump 12 and heater 13 in this example, can be used to detect temperature of air or water, as well as to determine, in conjunction with sensor component 92, whether and when liquid is being delivered to the heater 13.

[0028] The controller 16 can control various components of the beverage machine 100 in different ways based on signals from the sensor 9 regarding detected physical characteristics. In some embodiments, the controller 16 can provide an indication to the user to add liquid to the tank 61 as well as shut down or reduce a heating rate of the heater 13 if the sensor 9 detects the absence of liquid. The sensor 9 can also provide an indication that the tank 61 is removed from the machine 100 if the sensor 9 detects the absence of liquid while the pump 12 is drawing water from the tank 61. That is, if the tank 61 is removed as the pump 12 is pulling liquid from the supply line 63, liquid will no longer be provided to the inlet side of the supply line 63 and the pump 12 will empty the supply line 63. Once liquid is drawn past the sensor component 91, the sensor component 91 will no longer detect liquid, indicating that the tank 61 has been removed. In this case, the controller 16 can provide an indication to the user to replace the tank 61, stop pump and heater operation, etc.

[0029] In some embodiments, such as those detailed with reference to FIGs. 3-5, the sensor 9 can include circuit elements and be electrically powered by a non-isolated power supply 7 that receives input electrical power via a mains power connection 8 (such as a plug arranged to connect with a wall outlet or other power source) and conditions the input power to provide output power to the sensor 9. The input electrical power to the power supply 7 can be arranged in various ways, but in general will be at a higher voltage than that used by the sensor 9 and other components of the machine 100. As an example, the input electrical power can be about 120 Volts AC as provided within some residences. The non-isolated power supply 7 can be arranged to reduce the voltage of the input electrical power, e.g., to 120 Volts AC, and to convert the input electrical power to direct current, e.g., 120 Volt AC can be converted to 12 Volt DC.

[0030] The non-isolated power supply 7 can use a plurality of impedances (e.g., resistors) to reduce the voltage of the input electrical power, and a voltage converter to convert the 120 Volt AC to 12 Volt DC. The non-isolated power supply 7 can also include a voltage regulator or other component to reduce the voltage of the converted DC power, e.g., to reduce the 12 Volt DC to 3.3 Volts DC. The 3.3 Volt DC output electrical power can be used to power the sensor circuit 9 as well as other components of the machine 100, such as parts of the controller 16. Similarly, the 12 Volt DC power can be used to power other components, such as the pump 12 and / or parts of the controller 16. In some cases, some components such as the heater 13 can be powered by unmodified input power, e.g., the input electrical power can be selectively directly connected to the heater 13 using relay switches or other components controlled by the controller 16. These are only illustrative embodiments, however, and the non-isolated power supply 7 can be arranged to produce other voltage levels using any suitable components. Regardless, the nonisolated power supply 7 employs a common ground or circuit neutral for input and output power. Note as well that the machine 100 can employ other types of power supplies than a nonisolated power supply, such as isolated power supplies, to power beverage machine components including the sensor 9.

[0031] FIG. 3 is a circuit diagram of an exemplary sensor 9 that can be employed in the FIG. 2 arrangement and others. The metallic probes of the sensor components 91, 92 are shown with a simplified electric model of water as an exemplary medium between them. When the medium is water, as in the exemplary illustration, the capacitance (C_Medium) may be 2.1 nanofarad (nf) and the resistance (R_Medium) may be 1800 kilo-ohm (K). Each of the values varies with the medium and resistance may vary with ionic content and probe design. Prior approaches to detecting whether liquid is present in a beverage machine rely on the conductivity (resistance) of water (e.g., by using direct current (DC) excitation). However, these approaches are sensitive to the ionic content of water. That is, conductivity of water can vary widely based on ionic content and impurities in water such that threshold values used to detect the presence of water with a given ionic content may not apply to water with a different ionic content, for example. Thus, demineralized water may be difficult to detect with prior approaches. According to the approach described with reference to the exemplary embodiments illustrated in FIGs. 3-5, both the conductivity and capacitance of a medium are used to detect the presence of a liquid.

[0032] This may be reflected in the use of alternating current (AC) or pulsating DC excitation and in multiple measurements of voltage resulting from each excitation pulse cycle, as detailed. While an AC changes direction such that the resulting voltage (referred to as AC excitation forexplanatory purposes) spans between positive and negative values (e.g., between +120 Volts and -120 Volts for an average of 0 Volts over a cycle), a pulsating DC refers to switching DC voltage on and off such that the DC current oscillates in amplitude over a cycle (i.e., pulsating DC is also periodic). Because DC does not change direction like AC, the average voltage resulting from pulsating DC (referred to as pulsating excitation for explanatory purposes) is a non-zero value. For example, an exemplary pulsating excitation voltage may be a 3.0 Volt square wave that is 3.0 Volts for 50 percent of the time such that the average voltage over a pulsating DC cycle is 1.5 Volts. As noted, multiple voltage measurements may be taken within one pulsating excitation cycle. For example, voltage measurement, at analog-to-digital converter (ADC) 330, may be obtained twice per excitation pulse cycle and may additionally be obtained when / where the two measurements are expected to have the largest difference.

[0033] The optional shunt resistor (R_shunt) 310 may be included to limit the voltage at the analog-to-digital converter (ADC) input (ADC_in) 320. The ADC input 320 is to an ADC 330 that provides a digital signal for processing at the controller 16, as further discussed. One of the first or second conductive probes of the sensor components 91, 92 may be provided with an AC excitation via the general input / output (GPIO) pin 340. The power supply 7 may be used to obtain a voltage at voltage excitation pin (V_pin) 350 that is output as an excitation pulse at the GPIO pin 340. The resistor (R_series) 360 may be a current limiting resistor in series with the voltage pin 350 and may have a value that is chosen based on the ADC 330. One or both of the capacitors (C_seriesP, C_seriesN) 370P, 370N may be arranged, as shown, to limit the input to the ADC input 320 for safety. That is, regardless of the capacitance value of the medium is, the input to the ADC 330 is limited by the value of the capacitor(s) 370P, 370N. The value of the capacitors 370P, 370N may be on the order of 100 nF, for example. In terms of excitation, rather than detection, the capacitors 370P, 370N may convert a pulsating excitation at V_pin 350 (i.e,. a voltage resulting from pulsating DC) to AC excitation at the first and second conductive probes of the sensor components 91, 92. Each of the optional connectors 380 facilitates connection and disconnection between the sensor components 91, 92 and the detection portion including the excitation source (350).

[0034] The sensor 9 may operate based on control and determination by the controller 16. The controller 16 may control application of the excitation pulses to the conductive probe of the sensor component 91, according to the exemplary arrangement shown in FIG. 3. Voltage values between the sensor components 91, 92 resulting from the excitation pulses are measured at the ADC 330 and may be used to determine a presence of liquid (i.e., the medium being other thanair). Specifically, as shown in FIG. 3, voltage is measured using the same conductive probe (sensor component 91) that received the excitation pulse. Further, as shown, the detector of the sensor 9 is configured such that the voltage measured at the ADC 330 is a filtered version of the voltage signal between the sensor components 91, 92 determined by the capacitor 370P and resistor 310.

[0035] As noted, for each applied excitation pulse, multiple voltage values may be measured. That is, multiple voltage measurements (two or more measurements) may be obtained at the ADC 330 between excitation pulses. The controller 16 may then determine a difference between the minimum and maximum voltage values resulting from each excitation pulse. The controller 16 may compare the difference with a threshold value to determine if a liquid is present. The difference obtained when the medium is air (i.e., no liquid is present) may be higher than the difference obtained when any liquid is present. Thus, the difference may have to be below a threshold value for the controller 16 to determine the presence of a liquid. Alternately, a single voltage measurement may be compared with a threshold value or range to determine a presence of liquid (e.g., a voltage measurement resulting from an excitation pulse at the conductive probe of the sensor component 91 may have to be below a threshold value or between minimum and maximum threshold values in order for the controller 16 to indicate a presence of liquid).

[0036] FIG. 4 is a circuit diagram of another embodiment of an exemplary sensor 9 that can be employed in the FIG. 2 arrangement and others. The exemplary circuit arrangement of FIG. 4 is a simplified version of the circuit arrangement shown in FIG. 3. As discussed with reference to FIG. 3, an excitation pulse (e.g., pulsating excitation) is generated at voltage excitation pin (V_Pin) 450 and provided as excitation pulses at pin 460. Unlike in the exemplary embodiment of FIG. 3, the simplified embodiment of FIG. 4 is shown without the capacitors 370P, 370N or other components to convert pulsating excitation to AC excitation at the conductive probes of the sensor components 91, 92. Thus, the average current at the conductive probes of the sensor components 91, 92 is not zero in the exemplary embodiment of FIG. 4 (as it is when AC excitation is applied as in the exemplary embodiment of FIG. 3) but may be lower than the average current that results from prior approaches using (non-pulsating) DC excitation.

[0037] The resistor (Rseries) 470 may be a current limiting resistor in series with the excitation pin 450 and may have a value that is chosen based on the ADC 420. The optional connectors 480 facilitate connection and disconnection between the conductive probes of the sensor components 91, 92 and the detection portion including the excitation source (450). For eachexcitation pulse that is provided to the conductive probe of the sensor component 91, voltage between the conductive probes of the sensor components 91, 92, represented at ADC input (ADC_pin) 410 is measured by the ADC 420 and used by the controller 16 to determine whether the medium between the sensor components 91, 92 is a liquid (i.e., not air).

[0038] Specifically, as is the case for the detector shown in FIG. 3, the configuration of the voltage detection portion of the sensor 9 of FIG. 4 is as a voltage divider. Thus, for each cycle of excitation pulse, multiple voltage measurements are obtained at the ADC 420, and each voltage measurement is a fraction of the voltage between the sensor components 91, 92 that is based on values of the ADC resistor (R_adc) 430 and the ADC capacitor (c_adc) 440. As noted for the embodiment of FIG. 3, the controller 16 may obtain a difference between the maximum and minimum voltage measurements at the ADC 420 per excitation pulse and compare that difference with a threshold value to determine whether liquid is present between the sensor components 91, 92. In particular, the difference may have to be below the threshold value to indicate the presence of liquid. Alternately, as noted with reference to FIG. 3, a single voltage measurement may be used with one or a set of threshold values to detect a presence of liquid.

[0039] FIG. 5 is a circuit diagram of another embodiment of an exemplary sensor 9 that can be employed in the FIG. 2 arrangement and others. Like the sensor configurations shown in FIGs.3 and 4, the exemplary configuration of the sensor 9 shown in FIG. 5 includes optional connectors 580 that facilitate connection and disconnection between the sensor components 91, 92 and the detection portion. In the case of the exemplary sensor 9 of FIG. 5, the detection portion includes a transformer that provides galvanic isolation between the primary coil 520 and secondary coil 530. An optional shunt resistor (R_shunt) 510 is shown, as in the embodiment of FIG. 3. This shunt resistor 510 may limit the voltage on the primary side and, thus, on the secondary side, which effects the voltage at the ADC input (ADC_in) 560 provided to the ADC 570.

[0040] As is the case for the embodiments shown in FIGs. 3 and 4, the voltage measured at the ADC 570 represents voltage between the conductive probes of the sensor components 91, 92 and is based on excitation pulses provided from voltage excitation pin (V_Pin) 550 through the resistor (R_series) 540 that is in series and that may be a current limiting resistor. Like the exemplary embodiment shown in FIG. 3, the exemplary embodiment of FIG. 5 involves the application of AC excitation at the conductive probes of the sensor components 91, 92. The conversion of pulsating excitation at V_Pin 550 to AC excitation is based on mutual inductances LI at the primary coil 520 and secondary coil 530, as indicated, that serve a similar function inthe conversion as the capacitors 370P, 370N in the exemplary embodiment of FIG. 3. As previously noted, one or multiple voltage measurements may be obtained based on each excitation pulse and one or more threshold values may be used to detect a presence of liquid between the sensor components 91, 92.

[0041] To initiate a beverage cycle, a user may first insert a cartridge 1 into the dispensing station 15 and provide an indication (e.g., by pressing a button or other suitable step) to beverage machine 100 to prepare a beverage. At or before this time, the controller 16 can monitor the sensor 9 to assess whether liquid is present between the sensor components 91, 92. If the supply line 63 is provided with a controllable vent 64, the controller 16 can open the vent valve 64 to help ensure that the liquid level in the supply line 63 is equal to the liquid level in the tank 61. If no liquid is detected, the controller 16 can stop beverage formation and provide an indication to the user, e.g., via a user interface on the housing 10, that water or other liquid must be added and / or the tank 61 replaced. If liquid is detected, the controller 16 can proceed with beverage formation, e.g., including closing the vent 64, operating the pump 12 to deliver liquid to the heater 13. A temperature of the incoming liquid (e.g., detected by a temperature probe at sensor component 91) can be used by the controller 16 to control the heater 13 and / or pump 12. As an example, a power output of the heater 13 and / or a flow rate of the pump 12 can be adjusted to compensate for different incoming liquid temperatures. During pump 12 operation, the controller 16 can monitor the sensor 9 for the absence of liquid. If an absence of liquid is detected, the controller 16 can stop pump operation, heating and / or other functions, e.g., because the tank 61 may have been removed and / or a liquid supply in the tank 61 exhausted. The controller 16 can provide an indication to a user via the user interface that the tank 61 should be replaced to begin or restart beverage dispensing.

[0042] As noted above, operation of the pump 12, heater 13 and other components of the machine 100 may be controlled by the controller 16, which may include a programmed processor and / or other data processing device along with suitable software or other operating instructions, one or more memories (including non-transient storage media that may store software and / or other operating instructions), temperature and liquid level sensors, pressure sensors, input / output interfaces (such as a user interface on the housing 10), communication buses or other links, a display, switches, relays, triacs, or other components necessary to perform desired input / output or other functions. A user interface may be arranged in any suitable way and include any suitable components to provide information to a user and / or receive information from a user, such as buttons, a touch screen, a voice command module (including a microphoneto receive audio information from a user and suitable software to interpret the audio information as a voice command), a visual display, one or more indicator lights, a speaker, and so on.

[0043] While aspects of the disclosure may be used with any suitable cartridge, or no cartridge at all, some cartridges may include features that enhance the operation of a beverage machine 100. As is known in the art, the cartridge 1 may take any suitable form such as those commonly known as a sachet, pod, capsule, container, tablet, or other. For example, the cartridge 1 may include an impermeable outer covering within which is housed a beverage medium, such as roasted and ground coffee or other. The cartridge 1 may also include a filter so that a beverage formed by interaction of the liquid with the beverage medium passes through the filter before being dispensed into a container 2. As will be understood by those of skill in the art, cartridges in the form of a pod having opposed layers of permeable filter paper encapsulating a beverage material may use the outer portion of the cartridge 1 to filter the beverage formed. The cartridge 1 in this example may be used in a beverage machine to form any suitable beverage such as tea, coffee, other infusion-type beverages, beverages formed from a liquid or powdered concentrate, etc. Thus, the cartridge 1 may contain any suitable beverage material, e.g., ground coffee, tea leaves, dry herbal tea, powdered beverage concentrate, dried fruit extract or powder, powdered or liquid concentrated bouillon or other soup, powdered or liquid medicinal materials (such as powdered vitamins, drugs or other pharmaceuticals, nutriaceuticals, etc.), and / or other beveragemaking material (such as powdered milk or other creamers, sweeteners, thickeners, flavorings, and so on). In one illustrative embodiment, the cartridge 1 contains a beverage material that is configured for use with a machine that forms coffee and / or tea beverages, however, aspects of the disclosure are not limited in this respect.

[0044] In some embodiments, a cartridge may be provided in the form of a beverage tablet. In some embodiments, the beverage ingredients of the beverage tablet have been compacted to form the tablet. The beverage tablet may be able to hold its own shape, and thus may not require individual packaging to prevent dispersing of the beverage ingredients prior to use in forming a beverage. In some embodiments, the tablet may be coated. In some embodiments, the beverage tablet may directly contact a beverage machine without intervening packaging containing the beverage tablet. For example, in some embodiments, the coating of the beverage tablet, or the compacted ingredients (e.g. coffee grounds) of the tablet, may directly contact a beverage machine without intervening packaging.

[0045] Also, the disclosure may be embodied as a method, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way.Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0046] As used herein, “beverage” refers to a liquid substance intended for drinking that is formed when a liquid interacts with a beverage material, or a liquid that is dispensed without interacting with a beverage material. Thus, beverage refers to a liquid that is ready for consumption, e.g., is dispensed into a cup and ready for drinking, as well as a liquid that will undergo other processes or treatments, such as filtering or the addition of flavorings, creamer, sweeteners, another beverage, etc., before being consumed.

[0047] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0048] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0049] Having thus described several aspects of at least one embodiment of this disclosure, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

CLAIMS1. A beverage machine comprising: a liquid supply tank configured to provide liquid for use in forming a beverage, the liquid supply tank having an internal volume with a floor; a conduit configured to receive liquid from the liquid supply tank, the conduit being external to the internal volume of the liquid supply tank; and a sensor configured to detect a presence of liquid in the conduit, the sensor comprising: probes located within the conduit and at a height within the conduit that is above the floor of the liquid supply tank, and a controller configured to provide an alternating current (AC) excitation or pulsating excitation to the probes, wherein voltage values between the probes resulting from a cycle of the AC excitation or pulsating excitation are used to determine the presence of liquid in the conduit.

2. The machine according to claim 1, further comprising a dispensing station configured to form a beverage, wherein the conduit fluidly connects the liquid supply tank to the dispensing station.

3. The machine according to claim 2, wherein the dispensing station comprises a brew chamber that uses the liquid from the liquid supply tank to form the beverage.

4. The machine according to claim 1, wherein the liquid is demineralized water.

5. The machine according to claim 1, wherein the sensor additionally comprises a detector configured to obtain the voltage values resulting from the AC excitation or pulsating excitation including a first voltage value and a second voltage value between the probes resulting from the cycle of the AC excitation or pulsating excitation.

6. The machine according to claim 5, wherein a difference between the first voltage value and the second voltage value is used to determine the presence of the liquid.

7. The machine according to claim 5, wherein the detector is configured as a voltage divider with an analog-to -digital converter (ADC) arranged to measure the voltage values.

8. The machine according to claim 5, wherein the detector is configured with a transformer that provides galvanic isolation between the liquid and an electrical detection circuit of the detector.

9. A method for sensing liquid in a beverage machine comprising: applying alternating current (AC) excitation or pulsating excitation to a first probe located in the beverage machine; and obtaining voltage measurements from the first probe to detect voltage values between the first probe and a second probe in the machine, wherein the voltage values result from application of a cycle of the AC excitation or pulsating excitation, and two or more of the voltage values are used to determine a presence of the liquid.

10. The method according to claim 9, wherein the obtaining the voltage measurements includes obtaining three or more of the voltage measurements resulting from application of a same cycle of the AC excitation or pulsating excitation.

11. The method according to claim 10, further comprising identifying a minimum voltage value among the three or more of the voltage measurements and identifying a maximum voltage value among the three or more of the voltage measurements.

12. The method according to claim 11, further comprising obtaining a difference between the minimum voltage value and the maximum voltage value, wherein determining the presence of the liquid includes comparing the difference with a threshold value.

13. The method according to claim 9, wherein determining the presence of the liquid includes determining the presence of demineralized water.

14. A system in a beverage machine comprising: probes disposed in the beverage machine; a controller configured to apply alternating current (AC) excitation or pulsating excitation to the probes; and a detector configured to obtain first and second voltage measurements indicating respective first and second voltage values between the probes resulting from application of acycle of the AC excitation or pulsating excitation, wherein the first and second voltage values are used to determine a presence of water.

15. The system according to claim 14, wherein the detector is further configured to obtain a third voltage measurement indicating a third voltage value resulting from a same cycle of the AC excitation or pulsating excitation, and is configured to identify a minimum voltage value and a maximum voltage value among the first voltage value, the second voltage value, and the third voltage value.

16. The system according to claim 15, wherein the detector is configured to obtain a difference between the minimum voltage value and the maximum voltage value and to determine the presence of water based on comparing the difference with a threshold difference value.

17. The system according to claim 14, wherein the detector includes a voltage divider and an analog-to-digital converter (ADC) configured to obtain the first voltage measurement and the second voltage measurement.

18. The system according to claim 14, wherein the detector includes a transformer to provide galvanic isolation between the water and an electrical detection circuit of the detector.

19. The system according to claim 14, wherein the water is demineralized water.

20. The system according to claim 14, wherein the probes are arranged to determine the presence of water in a conduit arranged to fluidly connect a liquid supply tank to a dispensing station of the machine.

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