JP2641554B2 - Vending machine induction heating device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating device for a vending machine that hot-sells (hereinafter called HOT sale) by heating a canned beverage such as coffee at the time of sale.

2. Description of the Related Art In recent years, there has been proposed a vending machine that applies induction heating technology to induction-heat a canned beverage stored at a refrigerated or normal temperature at the time of sale and sells the hot beverage by HOT. As it is difficult to accurately detect the temperature of a canned beverage during induction heating as disclosed in Japanese Patent Application Laid-Open No. 52-89399, this type of vending machine has an appropriate canned beverage. In most cases, a constant time method is used in which heating is performed for a fixed time at a constant output in order to sell at a temperature.

Problems to be Solved by the Invention However, in such a configuration, the heating efficiency varies with the input voltage as shown in FIG. There was a problem that temperature could not be achieved.

In the experiment, input voltage 200V ± 15%, heating output 2.40KW, diameter
As a result of heating measurement of a can beverage having a content of 250 g of 53 mm, a difference of about ± 1.5% was generated in terms of heating efficiency. For this reason, when selling chilled and stored canned beverages (initial temperature 4 ° C) with the HOT selling temperature raised to 60 ° C, the temperature of the canned beverages after heating is about ± 1.1 ° C
Will vary.

The present invention has been made in view of the above problems, and provides an induction heating device of a vending machine for raising a canned beverage to an appropriate HOT selling temperature.

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 induction heating of a canned beverage, and a high frequency for converting low frequency power from a commercial power supply to high frequency power. A power conversion device, a heating control unit that controls the high-frequency power output from the high-frequency power conversion device to be constant, a timer that integrates the heating time, and an input voltage detector that detects an input voltage to the high-frequency power conversion device, Timer correction means for correcting the integration time of the timer according to a signal from the input voltage detector,
Drive means for driving the heating control means by a control signal from a timer.

According to the present invention, the input voltage detector detects the input voltage to the high-frequency power converter, and the timer correction means corrects the time accumulated in the timer based on the detection result. Then, the heating control means is driven by the driving means, and the high-frequency power converter is controlled to a constant output so that the canned beverage always has an appropriate HOT selling temperature.

FIG. 1 is a configuration diagram of an induction heating device for a vending machine according to the present invention. Reference numeral 1 denotes a heating coil for induction heating the canned beverage 2. Reference numeral 3 denotes a high-frequency power converter that converts low-frequency power from the commercial power supply 4 to high-frequency power and supplies the high-frequency power to the heating coil 1. Reference numeral 5 denotes heating control means for operating / stopping the high-frequency power converter 3 at a predetermined heating output. Reference numeral 6 denotes an input voltage detector for detecting an input voltage to the high-frequency power conversion device 3, and the output thereof is input to the control device 7. The control device 7 is HO
A driving means 9 for driving the heating control means 5 in response to a sales start signal from the group of sales switches, and a timer for converting the heating time and outputting a heating end signal to the driving means 9 in a specified time.
And timer correction means 11 for correcting the accumulated time of the timer 10 based on the detection signal from the input voltage detector 6.

 Next, a timer correction method will be described.

Now, assuming that the heating efficiency is η, a canned beverage (initial temperature 4 ° C) with a diameter of 53mm and a content of 250g is heated at 2.4KW and the HOT selling temperature (60
℃), the heating time t (seconds) is: t = 4.19 × 0.25 × 56 (2.4 × η) ... (1) Since 4.19 is determined by the proportionality constant, the heating output is constant (2.4KW) If the efficiency is also constant, the heating time is determined in one way from equation (1).
However, in actuality, as shown in FIG. 4, even if the heating output is constant, the heating efficiency changes with the input voltage. Therefore, in order to raise the HOT selling temperature (60 ° C.), it is necessary to heat for a time corresponding to this heating efficiency. is there. As shown in FIG.
Since the heating efficiency changes by 3% due to the change of 60V, the heating efficiency is a linear function of the input voltage, η = k × (Vin−200) +0.1815 (2) k = 0.03 / 60 Vin is given by the effective value Can be Therefore, the heating efficiency according to the input voltage at the time of heating is obtained by the formula (2), and the heating time is determined by the formula (1) from the result, thereby always obtaining a constant temperature rise (56 deg) regardless of the input voltage. Can be.

FIG. 2 shows an example of a specific circuit of a main part. 1 is a coil for inductively heating the canned beverage 2, 12 is a capacitor for resonance, 13
Is a power switching semiconductor, 14 is a diode for reverse conduction operation connected in anti-parallel to the power switching semiconductor 13, 15 and 16 are rectifier bridge diodes and smoothing capacitors for full-wave rectification of the commercial power supply 4, and the above is low. A voltage-type resonance inverter circuit 17 that converts frequency power into a high-frequency power converter is configured, and this corresponds to the high-frequency power converter 3. The control device 7 includes a microcomputer 18 and peripheral circuits. The microcomputer 18 has a CPU, ROM,
This is a so-called one-chip microcomputer having a RAM and an input / output unit. The input voltage detector 6 is a resistor 19 that divides the input voltage to the voltage-type resonant inverter circuit 17 into a low voltage (1/100).
Consists of 20. The detection signal from the input voltage detector 6 is A /
The input section of the microcomputer 18 is connected via the D converter 21. As a result, the detection signal from the input voltage detector 6 is converted into a binary code, and is read into the microcomputer 18. The microcomputer 18 implements a peak hold function on a program so as to store a peak value within a certain period of time. The HOT sales switch group 8 is input to the microcomputer 18 to determine whether or not it has been pressed. The output of the microcomputer 18 is connected to the heating control means 5 for controlling the voltage-type resonance inverter circuit 17.

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.

When a HOT sale start signal is input from the HOT sale switch group 8 (step 101), R in the microcomputer 18
In accordance with the procedure of the program shown in the flowchart of FIG.
In step W), heating is started (step 102), and at the same time, the timer 10 in the microcomputer 18 adds up the heating time (step 103). Next, the microcomputer 18 measures the input voltage from the commercial power supply 4 during heating. The input voltage signal detected by the resistors 19 and 20 is converted into a binary code by the A / D converter 21 and read into the microcomputer 18 (step 104). In fact, microcomputer 1
What is read in 8 is the peak value of the input voltage divided (1
/ 100), and if the value from the A / D converter 21 is X, the effective value Vin of the input voltage at this time is Becomes This value is obtained by calculation and substituted into equation (2) to calculate the heating efficiency η at this input voltage, and this η is substituted into equation (1) to obtain a heating time t corresponding to the input voltage (step). 105). The time of the timer 10 for integrating the heating time corrected in this way is compared (step 106), and when they match, a control (stop) signal is output to the heating control means 5 to end the heating of the canned beverage (step 107). ). Then, the vending machine (not shown) carries out the canned beverage 2 and completes the HOT sale by induction heating (step 108).

According to the configuration of the above embodiment, the heating time is corrected according to the input voltage with respect to the heating efficiency that changes with the input voltage, so that the temperature of the canned beverage 2 can be constantly raised (56 deg). This makes it possible to heat and sell with very little variation relative to the hot selling temperature (60 ° C).

As described above, as is clear from the embodiments, the present invention detects the input voltage to the high-frequency power conversion device by the input voltage detector, and based on the result, calculates the time accumulated in the timer by the timer correction means. The heating control means is driven by the driving means with the control signal from the timer, and the high-frequency power converter is controlled to a constant output to correct the heating time according to the input voltage with respect to the heating efficiency that changes with the input voltage. As a result, the temperature of the canned beverage can always be raised by a certain temperature, thereby making it possible to carry out the heating and selling with very little variation with respect to the HOT selling temperature.

[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 circuit diagram of a main part of the embodiment, FIG.
FIG. 4 is a flowchart showing an example of an induction heating program according to the present embodiment. FIG. 4 is a diagram showing an input voltage-heating efficiency characteristic when the heating output is fixed. 1 ... heating coil, 2 ... canned beverage, 3 ... high frequency power converter, 4 ... commercial power supply, 5 ... heating control means, 6 ...
Input voltage detector, 9 ... driving means, 10 ... timer, 11 ...
... Timer correction means.

Claims (1)

(57) [Claims] 1. A heating coil for inductively heating a canned beverage, a high-frequency power converter for converting low-frequency power from a commercial power supply to high-frequency power, and a constant high-frequency power output from the high-frequency power converter. Heating control means, a timer for integrating the heating time, an input voltage detector for detecting an input voltage to the high-frequency power converter, and correcting the integrated time of the timer in accordance with a signal from the input voltage detector. An induction heating apparatus for a vending machine, comprising: a timer correction unit; and a driving unit that drives the heating control unit with a control signal from the timer.