JP3021796B2 - Vending machine heater control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater control device for a so-called hot and cold type vending machine having a compartment for warm storage having a heater and a compartment cooled by a cooling circuit.

[0002]

2. Description of the Related Art Conventionally, in such a hot and cold type vending machine, a plurality of types of warmed products such as canned coffee, etc., and canned juices, etc., which are kept cold, are simultaneously sold. Are divided into a plurality of storage compartments, which are heated to a predetermined temperature, and a storage compartment, which is cooled to a predetermined storage temperature by a cooling circuit including a refrigerating cycle including a compressor. Since the heat capacity of the products in each refrigerator differs depending on the type of product, and the remaining quantity also varies depending on the sales status of each product, a heater is provided in each refrigerator compartment and the temperature in each refrigerator is detected. The internal product is kept at a predetermined temperature by controlling the power supply to the heaters independently of each other.

[0003]

In such a vending machine, in addition to the heater, the power consumption of the compressor of the cooling circuit, the lighting circuit and the like is added, so that when the loads are simultaneously energized, the vending machine flows. There is a danger that the total current will exceed the safe current.

For example, the current of the compressor is 5 A, the current flowing in the lighting circuit and other control circuits is 2 A, and the current of the heater is 3 A.
Assuming that there are three currents in the storage compartment and three heaters, the total current when energized at the same time is
There is a problem that the current reaches 16 A (effective current value in each of the above cases), which is much higher than the safe current value of 13.5 A.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heater control device for a vending machine which solves the above problem and suppresses the total current flowing through the vending machine to a predetermined safe current value or less.

[0006]

According to the present invention, there are provided a plurality of heaters for heating a plurality of storage compartments.
0, 11 and a cooling circuit 14 for cooling the inside of the refrigerator
And a plurality of temperature detectors 2, 3, 4 for respectively detecting the temperature in the storage compartment in a vending machine equipped with a lighting circuit 15 and the like, and a control section for controlling energization of heaters 9, 10, 11. The control unit 5 includes temperature detectors 2, 3,.
Based on the output of 4, the heater 9, 10, 11 in the storage compartment corresponding to the output is controlled independently of each other, and further, the power supply timing to each heater 9, 10, 11 is shifted to automatically sell The configuration is such that the total current flowing through the machine is kept below the safe current value.

[0007]

When the temperature in the refrigerator decreases to the lower limit based on the output from each of the temperature detectors 2, 3, and 4, the control section 5 energizes the heaters 9, 10, and 11, and the temperature rises to the upper limit. Then, the power supply to the heaters 9, 10, and 11 is cut off to keep the product at a predetermined temperature. However, when the energizing periods of the heaters 9, 10, and 11 overlap and the total current value flowing to the vending machine exceeds a predetermined value (safe current value), the energizing timing of the heaters 9, 10, and 11 is shifted, and Keep the current value below the safe current value.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an electric circuit diagram of a heater control device 1 of a vending machine according to the present invention. In the embodiment, the present invention is applied to a vending machine having three hot storage compartments (not shown) and a total of four cold storage compartments.

In FIG. 1, the temperature (air temperature) in each storage compartment is detected by temperature detectors 2, 3, and 4 composed of a thermistor or the like. It is input to the control unit 5 composed of a computer. The output of the control unit 5 includes a triac 6,
Gates 7 and 8 are connected. Triac 6, 7, 8
Are connected in series with heaters 9, 10, and 11, each of which is an electric heater, to a 100 VAC power supply. The heaters 9, 10, 11 are arranged corresponding to the respective temperature detectors 2, 3, 4 so as to heat the interior of the storage compartment.

[0010] The operation state of the cooling circuit 14 is further input to the control unit 5. The cooling circuit 14 is constituted by a well-known refrigeration cycle equipped with a compressor. The operation of the compressor is stopped by a temperature sensing operation of a thermostat (not shown) for detecting the temperature in the refrigerator, and the product in the refrigerator is stopped. Is kept at a predetermined refrigeration temperature. The operating state of the compressor (not shown) is input to the control unit 5.

Further, a control circuit 16 serving as a power supply for the lighting circuit 15 of the vending machine and the control unit 5 itself is provided for the AC 100 V power supply.
Is connected, and the lighting state of the lighting circuit 15 is also input to the control unit 5. Further, a zero voltage point detection circuit 13 for detecting a point at which the voltage becomes zero is connected to the AC 100 V power supply,
The output is input to the control unit 5 and AC100V
The output of the total current detection circuit 18 including the current transformer (CT) 17 connected to the power supply is also input to the control unit 5.

Next, the operation of the control unit 5 will be described with reference to the timing charts of FIGS. The control unit 5 controls only the energization of the heaters 9, 10, and 11, and
In FIG. 2, when the compressor of the cooling circuit 14 is stopped (OFF), the temperature detector 2 (or 3, 3) detects that the temperature in a certain storage has dropped to the lower limit temperature, for example, + 55 ° C. When 4) is detected, the corresponding heater 9 (1)
A signal is sent to the gate of the triac 6 (7, 8) at 0, 11) to trigger and conduct (ON), and the heater 9 (1) is turned on.
0, 11), and when the temperature detector 2 (or 3, 4) detects that the temperature has risen to the upper limit temperature, for example, + 60 ° C., the corresponding heater 9 (1)
0, 11), the signal to the gate of the triac 6 (7, 8) is cut off, and the heater 9 (1) is turned off.
The heat generation of 0, 11) is stopped. These controls are performed independently for each storage compartment, thereby keeping the products in each storage compartment at a predetermined temperature.

At this time, the control unit 5 includes a zero voltage point detection circuit 13
The zero voltage point of the AC100V power supply is detected based on the output of the triac 6, and at the timing when the voltage becomes zero, each triac 6,
Trigger gates 7 and 8. Thereby, generation of noise is suppressed.

The current flowing through the compressor of the cooling circuit 14 during operation is 5 A, the current flowing through the lighting circuit 15 and the control circuit 16 is 2 A, and the current flowing through one heater is 3 A. In this case (all effective current values), while the compressor of the cooling circuit 14 is stopped (OFF), the total current is maintained even during the period from T1 to T2 when all the heaters 9, 10, and 11 are energized in FIG. 11A, which is within the safe current. Therefore, the control unit 5 continuously energizes the heaters 9, 10, and 11 from the lower limit temperature to the upper limit temperature based on the outputs of the temperature detectors 2, 3, and 4, respectively.

However, when all heaters 9, 10, and 11 are energized at the next T3, the cooling circuit 14
When the compressor is started (ON), the total effective current value becomes 16 A, which exceeds the safe current value.

Therefore, the controller 5 energizes the heaters 9, 10 and 11 by the control shown in FIGS. 3 to 5 during the operation (ON) of the cooling circuit 14. That is, FIG. 3 shows the energization timing of each of the heaters 9, 10, and 11 in an enlarged manner. Here, a continuous energization period to each of the heaters 9, 10, and 11 is a pulse having a width of at least several seconds. Are shifted so that there are no more than two overlaps,
Energize in order. As a result, the total effective current value becomes 13 A at the maximum, and the total current value can be suppressed within the safe current value.

When the capacity of the heaters 9, 10, and 11 is large and the current value is, for example, 4 A, it is preferable to shift the pulses one by one so as not to overlap each other as shown in FIG. When it is not necessary to energize any of the heaters (for example, 11), only the heaters 9 and 10 are naturally energized as shown in FIG. Thereby, also in this case, the total current value can be suppressed to 11A.

Each pulse is stopped when the temperature in the storage room reaches the upper limit temperature + 60 ° C., and stops at the lower limit temperature + 60 ° C.
Needless to say, it is controlled so that it occurs again when the temperature drops to 55 ° C. Such forward feeding is performed only during the operation of the cooling circuit 14. When the cooling circuit 14 is stopped, the continuous feeding is resumed. Further, when the control of the progressive feeding is started, first, at the time when the compressor is started, the triac 6 of the heater (9 in FIG. 2) in the storage compartment which is closest to the upper limit temperature at that time is turned off (OFF). If so, the influence on the temperature control in each storage compartment can be minimized.

The above is a control in the case where the effective current value flowing to each heater is normal. However, if a failure occurs in any of the heaters and an abnormal current flows in the circuit and exceeds the safe current value, The total current detection circuit 18 detects this and generates an output. The control unit 4 stops the energization of each load thereafter based on the output of the full current detection circuit 18 or shifts to the heater control of FIG. 3 to FIG. 5 even if the cooling circuit 14 is stopped, and Activate the alarm device that does not work.

[0020]

According to the present invention, if the total current value flowing through the vending machine exceeds a predetermined safe current value due to the overlapping of the energizing periods to the heaters in the plurality of storage compartments, the heaters are not supplied to the respective heaters. Since the energization timing is shifted to suppress the total current value to a value equal to or less than the safe current value, it is possible to control the temperature in the storage compartment while preventing overheating of the wiring due to a large current and a fire accident. In particular, when a large-capacity heater is used, a great effect is exhibited.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of a heater control device of a vending machine.

FIG. 2 is a timing chart showing a state of energizing a cooling circuit and each heater.

FIG. 3 is a timing chart showing an example of the timing of energizing each heater.

FIG. 4 is a timing chart showing another embodiment of the timing of energizing each heater.

FIG. 5 is a timing chart showing an example of energization timing to each heater showing another situation of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heater control device 2 Temperature detector 3 Temperature detector 4 Temperature detector 5 Control part 9 Heater 10 Heater 11 Heater 14 Cooling circuit 15 Lighting circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G07F 9/10 G07F 9/00

Claims (1)

(57) [Claims] 1. A vending machine comprising: a plurality of heaters for heating a plurality of insides of a refrigerator; a cooling circuit for cooling the inside of a refrigerator; an illumination circuit; and the like. It comprises a plurality of temperature detectors for respectively detecting the temperature in the storage compartment, and a control section for controlling the energization of the heater. The vending machine is characterized in that the heaters in the refrigerator are independently controlled to be energized, and when the total current flowing through the vending machine exceeds a predetermined safe current value, the respective heaters are energized at a shifted timing. Heater control device.