JP2578950B2 - Vending machine induction heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating device for a vending machine that heats and sells (hereinafter called HOT sale) canned beverages such as coffee and sports drinks by induction heating.

2. Description of the Related Art In recent years, vending machines that apply an induction heating technology to instantly heat canned beverages at the time of sale and sell HOTs have been proposed. Hereinafter, a conventional induction heating device of a vending machine will be described. FIG. 8 is a block diagram of a conventional induction heating device of a vending machine. Reference numeral 1 denotes a heating coil for induction heating the canned beverage 2. Reference numeral 3 denotes a high-frequency power converter for converting low-frequency power from the commercial power supply 4 into constant high-frequency power and supplying the high-frequency power to the heating coil. The high-frequency power is electromagnetically induced in the can and heated. Reference numeral 5 denotes a control device that operates / stops the high-frequency power conversion device 3 upon receiving a sales signal from the HOT sales switch group 6.

The operation of the induction heating device of the vending machine configured as described above will be described. First, when any one of the HOT sales switch groups 6 is pressed, the canned beverage is introduced into the heating coil 1 from a storage (not shown) in which the canned beverage 2 is stored at a refrigerated or normal temperature. Next, the control device 5 operates the high-frequency power conversion device 3 to inductively heat the canned beverage 2 at a constant heating output for a fixed time, and
It is sold at a high selling temperature.

However, the content of the canned beverage is limited because it is heated to a predetermined HOT selling temperature by heating at a constant heating output for a fixed time. A solution to this problem has been proposed in the public relations of Japanese Utility Model Publication No. 54-23695. FIG. 9 shows a control device for judging the size (content) of a canned beverage proposed in this publicity. 1 is a heating coil for inductively heating canned beverages 2a and 3b having different contents. This heating coil has a content of 250g and a height of 132.5mm
Of canned beverage 2a and canned beverage 2 of 190g in height and 104.5mm in height
b is introduced. Reference numeral 7 denotes a selection lever for selecting the two types of canned beverages 2a and 2b, and reference numeral 8 denotes a selection switch that is interlocked with the operation of the selection lever 7.

The operation of the vending machine (not shown) at the time of HOT sale, including the operation of the control device for determining the size of the canned beverage of the vending machine configured as described above, will be described.

In FIG. 9, a canned beverage product is selected and the heating coil 1 is selected.
When 250 g of canned beverage 2a is introduced, the selection lever 7 is pushed by the can wall and the selection switch 8 is turned off. Meanwhile, 190
When the can beverage 2b having a short g is introduced, the sorting lever 7 does not come into contact with the can wall, so it jumps upward and the sorting switch 8 is turned on by this operation. That is, the control device shown in FIG. 8 determines the content of the canned beverage, the 250g canned beverage 2a generates an OFF signal of the selection switch 8, and the 190g canned beverage 2b generates an ON signal. In response to the ON / OFF signals, the conventional induction heating device of the vending machine energizes the heating coil for a time corresponding to the internal capacity, and heats to a predetermined HOT selling temperature for sale.

Problems to be Solved by the Invention However, in the above configuration, it is not possible to determine the type (structure) of the can of the can beverage even if the content of the can beverage can be determined. In recent years, there are three-piece cans 2 and two-piece cans 2 'as shown in FIGS. 10 and 11, even steel can beverages of the same content suitable for induction heating. The two-piece can 2 'has been conventionally used for aluminum cans, and this technology has been adopted for steel cans. 0.1mm thinner than 0.2mm). Therefore, 3 pieces can 2 with the same heating power
When the two-piece can 2 'is heated, the temperature rise of the can wall becomes larger in the two-piece can 2'. If the heating output is increased unnecessarily in the case of the two-piece can 2 ', the coating on the inner wall of the can is peeled off. , And can burn. In the experiment, when the heating output was 2.0 KW, no abnormality such as peeling of the coating on the inner wall of the can was observed, but when the heating output was set to 2.4 KW, not only the coating on the inner wall of the can but also the burning of the can occurred. . In the case of 3 piece can 2, 2.4KW
No abnormalities such as peeling of the coating on the inner wall of the can were observed at all, but burning of the can occurred at 2.8KW.

On the other hand, a vending machine equipped with an induction heating device, unlike a heater-type HOT vending machine, takes several tens of seconds for heating from the time the sales switch is pressed until the canned beverage is carried out,
In order to shorten this time even a little, a method of increasing the heating output even a little is used. However, as mentioned above,
Since the upper limit of the allowable heating output differs between two-piece cans and two-piece cans, when selling these two types of cans in a HOT sale, the heating output must be reduced to match the two-piece cans, and the sales time There was a problem that the operating rate of the vending machine was reduced.

The present invention has been made in view of the above problems, and provides an induction heating apparatus for a vending machine that automatically determines the type (structure) of a can of a canned beverage without using a special mechanism component and controls a heating output according to the type of the can. Things.

Means for Solving the Problems In order to solve the above problems, an induction heating device for a vending machine according to the present invention comprises a heating coil for inductively heating canned beverages having different contents, the heating coil, a resonance capacitor, and power switching. A voltage resonance type inverter circuit composed of a semiconductor and converting DC power or low frequency power to high frequency power, a first voltage detection circuit detecting an input voltage of the inverter circuit, and a voltage generated in the power switching semiconductor. A second voltage detection circuit for detecting,
Can determination means for determining the type of can based on the detection value from the first and second voltage detection circuits, and heating output determination means for determining a heating output amount based on the type of can determined by the can determination means And driving means for controlling the amount of heating output of the inverter circuit in accordance with a control signal from the heating output determining means.

Operation The present invention has the above-described configuration. In the can determination means based on the voltage value detected by the first voltage detection circuit and the voltage value generated in the power switching semiconductor detected by the second voltage detection circuit when the can beverage is heated, the configuration described above. The type of can of the canned beverage is determined, the heating output amount is determined by the heating output determining means based on the determination result, and the heating output amount of the inverter circuit is determined by the driving means by the control signal from the heating output determining means. By controlling, it is possible to automatically heat the canned beverage by varying the heating output amount according to the type (structure) of the can.

FIG. 1 is a block diagram showing an embodiment of the present invention, wherein 1 is a heating coil for inductively heating canned beverages 2 having different contents, 9 is a resonance capacitor, 10 is a power switching semiconductor, and 11 is power. Diodes connected in reverse parallel to the switching semiconductor for reverse conduction operation. Rectifiers and capacitors 12 and 13 for full-wave rectification of the commercial power supply 4 are the voltage resonance type inverters for converting low frequency power to high frequency power. The circuit 14 is configured. The inverter circuit 14 includes an oscillation control circuit 16 that controls conduction / non-conduction of the power switching semiconductor 10 based on a detection signal from a current detector 15 that detects an input current.
To generate a constant high-frequency electric power, and the canned beverage 2 is induction-heated by the heating coil 1. Reference numeral 17 denotes a first voltage detection circuit for detecting an input voltage (rectified voltage in the present embodiment) of the inverter circuit 14, and 18 detects a voltage (collector-emitter voltage) generated in the power switching semiconductor 10 during heating. The second voltage detection circuit is connected to the can determination means 20 in the control circuit 19. The control circuit 19 includes a can determination means 20 for determining the type of the can based on the voltage values detected by the first and second voltage detection circuits 17 and 18, and a heating output amount based on the result determined by the can determination means 20. Means for determining heating output
21 and an oscillation control circuit for controlling the heating output of the inverter circuit 14 by a control signal from the heating output determining means 21.
A driving unit 22 for driving the driving unit 16 and a timer 23 for determining a time for driving the driving unit 22 in accordance with a control signal from the heating output determining unit 21 are provided. Further, the control circuit 19 is connected to the HOT sale switch group 6, and when a HOT sale start signal is input, heating is performed by the driving means 22 with a preset heating output (2.0 KW in this embodiment). To start the induction heating by driving the oscillation control circuit 16, and the second voltage detection circuit
The configuration is such that a voltage generated in the power switching semiconductor 10 is input from 18.

Next, the principle of determining the type of the can will be described with reference to FIGS. 2, 3, 4, and 5. FIG. FIG. 2 is a view showing a positional relationship between canned beverages having different contents and a heating coil, wherein the heating coil 1 includes a three-piece diameter 53 mm-190 g can 24, a three-piece diameter 53 mm-250 g can 25, and a can wall. Is wound in a cylindrical shape along the line. FIG. 3 shows operation waveforms of the power switching semiconductor 10 in the voltage resonance type inverter circuit 14, where V _CE is a collector-emitter voltage, and I _{c / d} is the sum of the collector current and the current flowing through the diode 11. Due to the characteristics of the voltage resonance type inverter, when the distance between the heating coil 1 and the object to be heated (canned beverage in this embodiment) changes, the operation waveform shown in FIG. 3 also changes. That is, as the distance increases, the peak values of V _CE and I _{c / d} , V _{CE (P)} and I _{c / d (P)} increase,
Conversely, the distance decreases as the distance decreases, so if the shape of the canned beverage in the heating coil 1 is different, the equivalent distance between the heating coil 1 and the canned beverage is different.
There is a difference between _{CE (P)} and I _{c / d (P)} . V _{CE (P)} and I _CE also _depend on the thickness of the induction-heated portion of the object to be heated.
There is a difference in _{c / d (P)} . That is, when comparing canned beverages having the same content, a two-piece can (0.1 mm) with a thin can wall has a higher value than a three-piece can (0.2 mm) with a thick can wall. Attention is paid to these two characteristics.

FIG. 4 is a characteristic diagram showing a change in V _{CE (P)} value according to the type of can according to the input value of the commercial power supply 4. As shown in the figure, the peak value V _{CE (P)} of the collector-emitter voltage is the lowest for a 3-piece diameter 53 mm-250 g can when focusing on a certain input voltage, then a 3-piece diameter 53 mm-190 g can and a 2-piece diameter. 53mm−
The price increases to 250g cans, and the 3-piece 53mm-190g cans are the highest. The value of V _CE of each can the fluctuation range of the commercial power supply 4 as 170V~230V is approximately proportional to the input voltage value. From this characteristic diagram, when the correction is made with the input voltage value of the commercial power supply 4 (for example, a value proportional to the input voltage value is subtracted from V _{CE (P)} and the value is set as V ′ _{CE (P)} ), the fourth The characteristic shown in FIG. 5 is a characteristic unrelated to the input voltage value of the commercial power supply 4 as shown in FIG. That is, the peak value V ' _{CE (P)} of the collector-emitter voltage corrected by the input voltage value is a three-piece diameter of 53 mm-250 g.
V ' _{CE (P)} <V1, V1≤V' for cans, 3-piece diameter 53mm-190g cans, 2-piece diameter 53mm-250g cans, and 2-piece diameter 53mm-190g cans regardless of the input voltage value _{CE (P)} <V2, V2 ≦ V '
_{CE (P)} <V3, V3 ≦ V ′ Take values in four voltage zones _{CE (P)} . This makes it possible to determine the type of canned beverage.

FIG. 6 shows an example of a specific circuit of a main part. Control circuit
Reference numeral 19 denotes a microcomputer 26 and peripheral circuits. The microcomputer 26 shown here has a CPU,
This is a so-called one-chip microcomputer having a ROM, a RAM, and an input / output unit. The first voltage detecting circuit 17 includes a first resistor 27 and a second resistor 28 for dividing the rectified DC voltage into a low voltage.
, A first diode 29 for holding the peak value of the divided voltage, and a first capacitor 30. Similarly, the second voltage detecting circuit 18 is divided into a third resistor 31 and a fourth resistor 32 for dividing a voltage generated in the power switching semiconductor 10 (same as a heating coil voltage) into a low voltage. A second diode 33 for holding the peak value of the applied voltage,
It comprises a second capacitor. The first voltage detecting circuit 17 and the second voltage detecting circuit 18 are each a first differential amplifier.
Connected to 35 negative-phase input terminals and 35 common-phase input terminals. The first differential amplifier 35 outputs a signal obtained by multiplying the difference between the voltage applied to the in-phase input terminal and the voltage applied to the negative-phase input terminal by several times. The output terminal of the first differential amplifier 35 is connected to an A / D converter 36 which converts the amplified analog signal into a digital signal and inputs the digital signal to the microcomputer 26. The HOT sales switch group 6 is input to the microcomputer 26 so as to determine whether or not the switch is pressed. An output from the microcomputer 26 for oscillating (heating) / stopping the oscillation control circuit 16 is connected to the oscillation control circuit 16 (output terminal O1). The oscillation control circuit 16 controls the conduction angle of the power switching semiconductor 10 so that the analog signal from the second differential amplifier 37 becomes constant, and controls the heating output. The current detector 15 includes a current transformer 38 for detecting an input current (alternating current), a rectifier bridge 39 for rectifying an output signal from the current transformer 38 and holding a peak value thereof, and a third capacitor 40. It is connected to the common mode input terminal of the differential amplifier 37. A fifth resistor 41, a sixth resistor 42, and a seventh resistor 41, which divide the power supply voltage (+ V _CC ), are connected to the negative-phase input terminal of the second differential amplifier 37.
The voltage given by the resistor 43 is input. Reference numeral 44 denotes a transistor for changing this voltage value, and its collector-emitter terminal is connected in parallel to the seventh resistor 43. The base of the transistor 44 is connected to the output terminal O2 of the microcomputer 26. The other components (inverter circuit 14) are the same as those in FIG.

Next, the operation of the induction heating device of the vending machine configured as described above will be described with reference to the flowchart of FIG. First, when there is a switch input for starting the HOT sale from the HOT sale switch group 6 (step 101), the microcomputer 2
6 operates (heats) from its output terminal O1 to the oscillation control circuit 16
A signal is issued, and heating is started at a heating output of 2.0 kW at which the two-piece can cannot be burned (step 102). At this time, an H-level signal is output from the output terminal O2 of the microcomputer 26, the transistor 44 is turned on, the seventh resistor 43 is short-circuited, and the power supply voltage is applied to the negative-phase input terminal of the second differential amplifier 37. (+ V
A constant voltage (V _2.0 ) obtained by dividing _CC ) by the fifth resistor 41 and the sixth resistor 42 is applied, and the oscillation control circuit 16 makes the analog signal from the second differential amplifier 37 constant. As described above, the heating output amount is controlled by controlling the conduction angle of the power switching semiconductor 10 to 2.0 KW output. And the second
The voltage applied to the in-phase input terminal of the differential amplifier 37 is a voltage value output from the current detector 15 and is V _{2.0 + α} ( _α is constant). That is, the oscillation control circuit 16 controls the voltage difference between the in-phase input terminal and the negative-phase input terminal of the second differential amplifier 37 to be α. When the heating is started, the operation waveform shown in FIG. 3 appears in the power switching semiconductor 10, and the peak value of the collector-emitter voltage is detected by the second voltage detecting circuit 18 and the first differential amplifier 35 The peak value of one input voltage to the in-phase input terminal is detected by the first voltage detection circuit 17 and input to the opposite-phase input terminal. Since the value corresponding to the input voltage from the commercial power supply 4 is subtracted (corrected) from the peak value of the collector-emitter voltage by the first differential amplifier 35, the first differential amplifier 35
The output voltage has a characteristic unrelated to the fluctuation of the input voltage as shown in FIG. Using this characteristic, the microcomputer 26 converts the output voltage from the first differential amplifier 35 into a digital signal by the A / D converter 36 and inputs the digital signal (step
103), the type of canned beverage 2 is determined. That is, the corrected peak value V ′ _{CE (P) of} the collector-emitter voltage becomes V
If lower than 1 (step 104), canned beverage 2 has a 3 piece diameter
A 53 mm-250 g can is set and the heating time is set to 15 seconds (step 105). Here, the heating time is set to 15 seconds because the temperature of the canned beverage 2 stored in the storage (not shown) of the vending machine in the present embodiment is 30 ° C., the HOT selling temperature is 58 ° C. In the case of a three-piece can, the output was calculated as 2.4 KW, with a heating efficiency of 83%. Similarly, if _{V1≤V'CE (P)} <V2 (step 106), the canned beverage 2 is a 3-piece can with a diameter of 53 mm-190 g and the heating time is set to 11.4 seconds (step 107). If the can has three pieces, an L-level signal is output from the output terminal O2 to set the heating output to 2.4 kW, and the transistor 44
Is turned off (step 108). As a result, a voltage value (V _{2.4) obtained by} dividing the power supply voltage (+ V _CC ) by the fifth resistor 41, the sixth resistor 42, and the seventh resistor 43 is supplied to the negative-phase input terminal of the second differential amplifier 37. ) Is input (V _2.4 > V _2.0 ). The oscillation control circuit 16 controls the voltage difference between the in-phase input terminal and the negative-phase input terminal of the second differential amplifier 37 so as to be α.
Heating output to phase input terminal of the differential amplifier 37 becomes V _2.4 -V _2.0) higher than the voltage detected current detector 15 at the time of 2.0KW for. That is, the current detector 15 outputs a voltage proportional to the current detected by the current transformer 38,
The input current is larger than when the heating output is 2.0 kW, and the heating output increases (in this case, 2.4 kW). And
In the case of a three-piece can, heating is performed for a set time with a heating output of 2.4 kW (step 109), and when the time is over, the canned beverage 2 is carried out and HOT sale ends (step 110). On the other hand, V2 ≦
If _{V'CE (P)} <V3 (step 111), the canned beverage 2 is a two-piece 53mm-250g can and the heating time is set to 18 seconds (step 112). The heating time was set at 18 seconds
In the case of a piece, the heating output was calculated as 2.0 KW. Similarly, when V3 ≦ V ′ _{CE (P)} , the canned beverage 2 is a two-piece can with a diameter of 53 mm to 190 g and the heating time is set to 13.7 seconds (step 113). In the case of a two-piece can, the heating output is kept at 2.0 kW (step 114), and the heating is performed for a set time (step 109).
Is carried out, and the HOT sale ends (step 110).

According to the configuration of the above embodiment, the type of the can of the canned beverage 2 is automatically determined without using any special mechanical parts, and the heating output is changed to the upper limit of the heating power allowed for the can according to the type of the can. The canned beverage 2 can be heated in the shortest time in each can without causing burning in the thin two-piece cans, and the content of the canned beverage 2 can be determined. The operating rate at which the beverage 2 can be sold can be improved. In addition, since the determination of the type of the can utilizes the electrical characteristics of the inverter circuit 14, the reliability is superior to that of the mechanical parts.

As described above, the induction heating device of the vending machine according to the present invention comprises a heating coil for inductively heating canned beverages having different contents, a resonance capacitor, and a power switching semiconductor. The first voltage detection circuit detects the input voltage of the voltage resonance type inverter circuit that converts the frequency power to the high frequency power, and the second voltage detection circuit detects the voltage generated in the power switching semiconductor. The type of the can is determined by the can determination means based on the detection value from the second voltage detection circuit, the heating output amount is determined by the heating output determination means based on the result, and the control signal from the heating output determination means is determined. Is used to control the amount of heating output of the inverter circuit, so that the type of canned beverage is automatically determined without using special mechanical parts, The heating output can be changed according to the type of can, so that the can beverage can be heated in the shortest time for each can without causing burning in the thin two-piece can with thin can walls, and the content of the can beverage Since the same vending machine can sell many kinds of canned beverages, the operating rate can be improved. Further, since the determination of the type of the can utilizes the electric characteristics of the inverter circuit, the can is more excellent in reliability than the case of the mechanical parts.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an induction heating device of a vending machine showing one embodiment of the present invention, FIG. 2 is a schematic sectional view showing a positional relationship between canned beverages having different contents and a heating coil, and FIG. FIG. 4 and FIG. 5 are voltage characteristic diagrams showing the principle for judging the type (structure) of cans of canned beverages in a voltage resonance type inverter circuit, FIG. 4 and FIG. FIG. 7 is a flowchart showing the operation of the induction heating device of the vending machine of this embodiment, FIG. 8 is a block diagram of the conventional induction heating device of the vending machine, FIG.
The figure is a cross-sectional view of a conventional can beverage content determination device,
FIG. 11 is an external view of a three-piece can and a two-piece can, respectively. 1 ... heating coil, 2 ... canned beverage, 9 ... resonance capacitor, 10 ... power switching semiconductor, 14 ... inverter circuit, 17 ... first voltage detection circuit, 18 ... second voltage detection Circuit, 20: can determining means, 21: heating output determining means, 22: driving means.

Claims (1)

(57) [Claims] 1. A heating coil for inductively heating canned beverages having different contents, a voltage resonance type inverter comprising the heating coil, a resonance capacitor and a power switching semiconductor for converting DC power or low frequency power to high frequency power. A circuit, a first voltage detection circuit that detects an input voltage of the inverter circuit, and a second voltage detection circuit that detects a voltage generated in the power switching semiconductor,
Can determination means for determining the type of can based on the detection value from the first and second voltage detection circuits, and heating output determination for determining a heating output amount based on the type of can determined by the can determination means Means for controlling the amount of heating output of the inverter circuit in accordance with a control signal from the heating output determining means.