JPH0779596B2 - Temperature control method and temperature control device for firing furnace in multi-stage electric oven - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric oven for baking confectionery and bread by heating the baking furnace with an electric heater installed in the baking furnace. The present invention relates to improvements in a temperature control method and a temperature control device for a firing furnace, which are performed in a multi-stage electric oven provided in, by controlling energization of an electric heater installed in each firing furnace.

[0002]

2. Description of the Related Art The temperature control means of a baking furnace in a multi-stage electric oven for baking bread and confectionery is a conventional one. Turning on / off of electricity to an electric heater such as simmering fire is automatically controlled by a temperature sensor provided at a predetermined portion in each firing furnace.

[0003]

[Problems to be Solved by the Invention] The conventional multi-stage type in which the electric power to the electric heaters provided on the hearth and ceiling of the firing furnace is automatically controlled by a temperature sensor provided in the firing furnace. There is a problem that it is difficult for the temperature control means of the baking oven in the electric oven to control the temperature in the baking oven while the bread dough is loaded into the baking oven and the baking operation is performed so as to keep the temperature in the target temperature range.

This is because the temperature inside the firing furnace is controlled by controlling the on / off of electric power to the electric heaters built in the hearth and ceiling of the firing furnace by a temperature sensor arranged in the firing furnace. When the temperature is set to around 200 degrees C set in the sensor, the electric heater heats up to a temperature far exceeding the set temperature by energization, whereas the baking furnace required for baking bread Since the internal temperature is around 200 ° C. described above, when the temperature in the firing furnace reaches the required temperature, the temperature becomes high even if the electric heater is turned off by the control by the temperature sensor. The temperature inside the firing furnace is the temperature set by the temperature sensor as it continues to be heated by the heat of the hearth itself including the electric heater and the holding member of the electric heater. Since becomes higher becomes wins above, control to be maintained in the range of target temperature within the firing furnace is due to the difficulty.

Further, the multi-stage electric oven has a large electric capacity by disposing electric heaters for upper and lower fires on the hearth and ceiling of each firing furnace provided in multiple stages inside the machine body. However, the bread and confectionery factories have an upper limit on the capacity for receiving commercial power, and it is not possible to freely set the capacity of the electric heater to be installed in each of the baking furnaces arranged in multiple stages. There are restrictions. Therefore, when adding firing furnaces in multiple stages, the electric heaters installed in each firing furnace must be selected with a small capacity so that the sum of their capacity falls within the regulation of the receiving capacity. This makes it more difficult to finely control the temperature in the firing furnace during firing work.

The present invention has been made in order to solve the above-mentioned problems occurring in the conventional multi-stage electric ovens, and is provided for each of the multiple electric heaters assembled in the firing furnaces arranged in multiple stages. It is an object of the present invention to provide a new means capable of delicately controlling the temperature of each firing furnace by turning on / off the power so as to keep each firing furnace within a desired temperature range set to a desired value. To do.

[0007]

SUMMARY OF THE INVENTION The present invention, however, has been completed based on the findings obtained by various studies for the above-mentioned purpose. That is, the electrothermal heaters provided in multiples by incorporating them in each of the firing furnaces arranged in multiple stages, the energization to them is selected by sequentially selecting one of the multiple electrothermal heaters by the rotary switch. , The selected electric heater is energized, and the selected one electric heater is sequentially switched by the rotation of the rotary switch. One electrothermal heater selected from the heaters is switched and circulated in sequence,
At this time, the time for energizing the selected one electric heater is set to a short time of about 10 seconds, and the electric heaters arranged in parallel in this series are sequentially switched at a certain time and selected. By setting each electric heater to be turned on sequentially for a short period of time set for each electric heater, compared to the case of energizing all of the electric heaters arranged in parallel at the same time, a multistage The time required to raise the temperature of each firing furnace to the desired temperature range is inversely proportional to the total capacity of the entire electric heater and the capacity of the selected electric heater However, it has been found that the temperature of each of the firing furnaces provided in multiple stages can be raised so that they are all in a uniform state.

After the temperature inside the firing furnace reaches a predetermined temperature, all of the electric heaters incorporated in the firing furnace are turned off by the operation of the temperature sensor that controls them individually. In the above, the rotation speed of the rotary switch is increased to extremely shorten the energization time to the feeding path of the electric heater to be selected, and the operation of the rotary switch is set to be equal to or lower than the set temperature from the multi-speed electric heater. Switch to the operation to search for the electric heater built into the firing furnace, which caused a firing furnace whose temperature fell below the set temperature.When searching for this, slow down the rotary speed of the rotary switch again. Then, only for the electric heater incorporated in the firing furnace that has reached the set temperature or lower, repeat for a short time until the firing furnace reaches the set temperature. When the electricity is turned on, the calorific value of the hearth including the electric heater and the holding member of the electric heater, which become hot when energized, heats the firing furnace for a while even after the energization is turned off. As a result, the phenomenon in which the firing furnace was heated above the set temperature was resolved by intermittently energizing the firing furnace for a short period of time, and the temperature inside the firing furnace was maintained. This is because the control by turning on / off the electric heater incorporated in was able to perform remarkably delicately.

Therefore, in the present invention, as means for achieving the above-mentioned object, the respective power feeding paths of the electric heaters respectively incorporated in the firing furnaces arranged in multiple stages are controlled by rotary switches. One of these power supply paths is sequentially selected and controlled to be turned on, and the operation of each electric heater is detected by a temperature sensor installed in each firing furnace. The temperature is controlled to be turned off when the set temperature set in the furnace is reached, and the rotation speed of the rotary switch is set so that all the temperatures in the firing furnaces arranged in multiple stages reach the set temperature. The multi-stage type is characterized in that it is controlled to rotate at a high speed and to rotate at a low speed by firing a firing furnace having a temperature lower than the preset temperature among firing furnaces arranged in multiple stages. As well as raise the temperature control method of the firing furnace in a gas oven, a baking furnace and arranged in multiple stages, incorporate respective electric heater in their firing furnace,
A rotary switch is connected to the electric power feeding paths of the electric heaters so as to sequentially select and turn on one of the electric power feeding paths by the rotary operation. Each control circuit is connected to turn off energization when each temperature in the temperature controller reaches the set temperature, and the rotary switch is set to its advance rate and all temperatures in each firing furnace are set. The temperature of the firing furnace in the multi-stage electric oven is characterized by connecting an oscillator that controls the firing speed to reach the set temperature and the firing speed to reach the set temperature in each firing furnace. A control device is proposed.

[0010]

Embodiments Next, embodiments will be described in detail with reference to the drawings. FIG. 1 shows an overall block circuit diagram of a temperature control device for a firing furnace in a multi-stage electric oven according to the present invention. FIG. 2 is an enlarged view of one half of the above, and FIG. 3 is another half of the same. It is a figure.

The electric oven of this embodiment is an example in which firing furnaces a are provided in three stages. In the figure, a-1 is a first-stage firing furnace, a-2 is a second-stage firing furnace, and a- -3 shows the baking furnace of the 3rd step.

Further, in the figure, reference numeral 1 is a temperature controller provided on a control panel of the machine body, which is a setting unit for setting a desired set temperature, a temperature set therefor and a measurement detected by a temperature sensor provided in the firing furnace a. An electric heater provided with a comparison circuit that compares the temperature and outputs a voltage proportional to the difference, and is provided in a pair in each of the firing furnaces a-1, a-2, and a-3 that are arranged in multiple stages. Heater heater consisting of 19-1 ・ 19
-3.19-5 and lower heat heater 19-2.19-4.1
Corresponding to 9-6, six stations are provided as shown in 1-1 to 1-6.

2-1 to 2-6 are electrically insulated amplifiers connected to the respective output sides of the six temperature controllers 1-1 to 1-6. , Outputs a voltage that is proportionally controlled to the input voltage, and outputs the temperature controller 1-1 to 1
-6 acts to prevent mutual interference of signal voltages.

3-1 to 3-6 are the temperature controllers 1-1 to 1
When there is a signal voltage output from -6, it is a relay drive section that increases the signal voltage to drive a relay, and is connected to each output side of the temperature regulators 1-1 to 1-6 separately. I am doing it.

Reference numerals 4-1 to 4-6 are control circuits composed of thyristor switches for controlling the energization time in proportion to the signal voltage input by a non-contact switch.
The above-mentioned upper heater 19 provided in -1, a-2, and a-3.
-1, 19-3, 19-5 and lower heat heater 19-2.1
9-4 and 19-6 are provided separately for the respective drive circuits.

Numeral 7 is a triple upper fire heater 19-1, 19
-A rotary switch for upper fire consisting of a ring counter that selects the power supply path to be energized from each of the power supply paths of 3 ・ 19-5.
・ Select one of the
It goes one by one and goes around, and by doing this
Outputs two signals and selects the power supply path.

Numeral 8 is a triple lower heat heater 19-2, 19
-A rotary switch for lower heat, which is composed of a ring counter for selecting a power supply path to be energized from among the power supply paths of 4-19-6, and is configured in the same manner as the rotary switch 7 for upper heat described above, Works the same way.

Reference numeral 6 is a top heat heater 19-1, 19-3.1, in which a rotary switch 7 for top heat and a rotary switch 8 for bottom heat are connected to a power supply path selected thereby.
9-5 and lower heat heater 19-2, 19-4, 19-
6, a self-oscillator that sends a signal to move forward every time length required to activate 6, which in this example emits a signal every 7 seconds, which results in rotary switch 7 and The lower heat rotary switch 8 is controlled so as to advance the power feeding path selected by them to the state of selecting the next power feeding path every 7 seconds, and the upper heat heater 19-connected to the selected power feeding path. 1.19-3.19-5 and the lower heat heater 19-2.19-4.19-6 are energized every 7 seconds.

Reference numeral 5 is a rotary switch 7 for the upper fire and a rotary switch 8 for the lower fire by the oscillator 6 described above.
By intermittently energizing the upper heater and the lower heater of each of the firing furnaces a-1, a-2, and a-3, the temperature of each firing furnace rises, and the upper heater and the bottom heater are heated. When all of the temperature sensors (not shown) arranged around the fire heater and provided in the firing furnace detect that the temperature has reached the set temperature, the rotary switch 7 for upper heat is used. And a self-oscillator for setting the rotary switch 8 for lower heat to advance at a high speed. In this example, a signal is oscillated at an extremely short interval of about 0.1 second, and the rotary switch for upper heat is rotated. The switch 7 and the rotary switch 8 for lower heat are advanced so as to advance at a high speed to orbit. As described above, the oscillator 5 has a temperature controller 1 that controls all the upper and lower fire heaters by operating the multiple upper and lower fire heaters so that all firing furnaces reach the set temperature. When the output of the signal voltage from all of 1 to 1-6 is stopped, it is controlled to be driven by it. Further, even if one of the temperature regulators provided in the above-mentioned multiple units outputs a signal voltage, that is, even if one of the temperature regulators provided in the multiple units falls below the set temperature. The drive is controlled to turn off when something comes out.

Numeral 9 widens the input signal from the rotary switch 7 for the upper heat to increase the upper fire relay 14-1, 14-2-1.
It is an upper fire relay drive unit that drives 4-3.

Numeral 10 amplifies the input signal from the lower fire rotary switch 8 to lower fire relays 15-1 and 15-2.
-It is a lower fire relay drive part which drives 15-3.

Reference numeral 11 indicates an upper heat heater 19-1, 19-3, 19 which supplies electric power when the rotary switch 7 for upper fire and the rotary switch 8 for lower fire select one power feeding path, respectively. -5 and lower heat heaters 19-2, 19-4, 19-6, one for each stage and 2
It is a changeover switch that changes to each step.

12-1, 12-2, and 12-3 are relay contacts x1, x2, and x3, respectively, provided in the power feed paths of the upper heat heaters 19-1, 19-3, and 19-5. It is a relay of the upper heat heater to drive.

13-1, 13-2, and 13-3 respectively have relay contacts x11, x12, and x13 provided in the power feed paths of the lower heat heaters 19-2, 19-4, and 19-6, respectively. It is a relay of the lower heat heater to drive. In addition, the relays 13-1, 13-2, 13-3 of the lower heat heater and the relays 12-1, 12-2, 1 of the above-mentioned upper heat heater.
2-3 supplies power to the circuit to which the relay contacts driven by them are connected, but at this time, if there is no signal voltage from the temperature regulators 1-1 to 1-6 connected to the circuit. Is a control circuit 4-1 composed of a thyristor switch.
Since ~ 4-6 is off, the electric heaters such as the upper heater and the lower heater are not energized.

Reference numerals 14-1, 14-2, and 14-3 are upper fire power supply line relays respectively provided on the three power supply lines selected by the upper fire rotary switch 7.

Reference numerals 15-1, 15-2, and 15-3 are lower fire power supply line relays provided on the three power supply lines selected by the lower fire rotary switch 8.

Reference numerals 16 and 17 are drive relays for switching the operation of the high speed oscillator 5 and the low speed oscillator 6.

Reference numerals 18-1, 18-3, and 18-5 are upper-fire search relays for searching the upper-heat heaters 19-1, 19-3, and 19-5 for the upper-heat heaters to be supplied with power. Top heat temperature controller 1-1.1- that controls the top heat heater
It is driven when there is a signal voltage from 3.1-1-5, and the drive searches for the upper heater that needs power supply. If there is no signal voltage from the upper heat temperature controller 1-1, 1-3, 1-5, it is not driven and the power supply is moved to the next upper heat heater.

Reference numerals 18-2, 18-4, and 18-6 are lower heat search relays for searching lower heat heaters to be supplied from lower heat heaters 19-2, 19-4, and 19-6. It works in the same way as the upper fire search relay to search the lower fire heater that needs power supply.

Next, the changeover switch 11 is switched to the position shown in FIG. 3, and when the rotary switch 7 for upper fire and the rotary switch 8 for lower fire select one power feeding path, they are simultaneously operated. The operation will be described for the case where the next-order power supply path is also energized, and the selected power supply path and the next-order power supply path are paired to be energized in two stages. To do.

The temperature of a predetermined portion inside the firing furnaces a-1, a-2, and a-3 at each stage is equal to or lower than the preset temperature set in each of the temperature controllers 1-1 to 1-6. In this case, the upper fire rotary switch 7 and the lower fire rotary switch 8 are controlled by the operation of the low speed oscillator 6 to advance at a low speed, and one of the three power supply paths is sequentially switched. Select over.

At this time, the rotary switch 7 for the upper fire
However, if you select the upper heat supply line, the upper heat supply line relay 14
-1 is driven, and the upper heat heater relay 12-1 and the upper heat heater relay 1 are connected via the A contact of the relay 14-1.
2-2 is operated. Thereby, the relay contact x1 of the upper heat heater relay 12-1 and the upper heat heater relay 12
-2 relay contact x2 is turned on, and the thyristor switches 4-1 and 4-3 turn the temperature regulator 1-1 of the first stage upper heater and the temperature regulator 1-3 of the second stage upper heater. In response to the signal voltage from the switch, those contacts are turned on and the first stage upper heater 19-1 and the second stage upper heater 19-3 are turned on.
Will be supplied with a voltage of 200V.

Also, a rotary switch 8 for lower heat,
By selecting the lower heat supply line, the lower heat supply line relay 15
-1 is driven, and the lower heat heater relay 13-1 and the lower heat heater relay 1 are connected via the A contact of the relay 15-1.
3-2 is operated.

As a result, the lower heat heater relay 13-1
The relay contact x11 and the relay contact x12 of the lower heat heater relay 13-2 are turned on, and the one-stage lower heat heater temperature controller 1-2 and the two-stage lower heat heater temperature controller 1-
The signal voltage from 4 is applied to the thyristor switch 4-2-4-4.
Then, those contacts are turned on, and the first stage lower heat heater 19-2 and the second stage lower heat heater 19-4 are turned on.
It comes to be supplied with a voltage of 0V.

When the selection of the upper heat power supply path and the lower heat power supply path is completed, the upper heat power supply path relay 14-1 is turned off,
Upper fire power supply line relay 12-1 and upper heat power supply line relay 12
-2 relay contacts x1 and x2 are also turned off, and the first stage upper heater 19-1 and the second stage upper heater 19
The power supply to -3 is stopped.

At the same time, the lower heat feeding path relay 15-1 is turned off, the relay contacts x11 and x12 of the lower heat heater relay 13-1 and the lower heat heater relay 13-2 are turned off, and the lower one stage. Power supply to the fire heater 19-2 and the two-stage lower heat heater 19-4 is stopped.

Next, if the rotary switch 7 for upper heat selects the upper heat feeding path and the rotary switch 8 for lower heat selects the lower heat feeding path, the selected upper heat feeding path is Drives the power feeding path relay 14-2, and its relay 1
The upper heat heater relay 12-2 and the upper heat heater relay 12-3 are operated via the A contact of 4-2.

As a result, the upper heater relay 12-2
The relay contact x2 and the relay contact x3 of the upper heat heater relay 12-3 are turned on, and the temperature regulator 1-3 of the two-stage upper heat heater and the temperature regulator 1-5 of the three-stage upper heat heater are turned on. The control circuit 4-3, 4-5 consisting of a thyristor switch receives the signal voltage from the
The second stage upper heater 19-3 and the third stage upper heater 19-5 are supplied with a voltage of 200V.

Further, the selected lower heat power supply path drives the lower heat power supply path relay 15-2, and the relay A of the relay 15-2 is driven.
The lower heat heater relay 13-2 and the lower heat heater relay 13-3 are operated via the contacts.

As a result, the lower heat heater relay 13-2
The relay contact x12 and the relay contact x13 of the lower heat heater relay 13-3 are turned on, and the two-stage lower heat heater temperature controller 1-4 and the three-stage lower heat heater temperature controller 1-
The signal voltage from 6 is applied to the thyristor switch 4-4-4-6.
Then, those contacts are turned on, and the two-stage lower heat heater 19-4 and the three-stage lower heat heater 19-6 are turned on.
It comes to be supplied with a voltage of 0V.

When the selection of the upper fire power supply path and the lower heat power supply path is completed, the upper heat power supply path relay 14-2 is turned off,
The relay contacts x2 and x3 of the upper heat heater relay 12-2 and the upper heat heater relay 12-3 are also turned off,
Power supply to the two-stage upper heat heater 19-3 and the third-stage upper heat heater 19-5 is stopped.

At the same time, the lower heat supply line relay 15-2 is turned off, and the relay contact of the lower heat heater relay 13-2 x 1
2 and relay contact of lower heat heater relay 13-3 x 1
3 is also turned off, and the power supply to the lower stage heater 19-4 of the second stage and the lower stage heater 19-6 of the third stage is also stopped.

Next, the upper fire rotary switch 7 selects the upper fire power supply path, and the lower fire rotary switch 8 is selected.
Alternatively, if the lower heat power supply path is selected, the selected upper heat power supply path drives the upper heat power supply path relay 14-3, and the upper heat heater relay 12-3 via the A contact of the relay 14-3.
And the upper heater relay 12-1 is operated.

As a result, the upper heat heater relay 12-3
The relay contact x3 and the relay contact x1 of the upper heat heater relay 12-1 are turned on, and the temperature regulator 1-5 of the three-stage upper heat heater and the temperature regulator 1-1 of the one-stage upper heat heater are The control circuits 4-5 and 4-1, which are composed of thyristor switches, receive the signal voltage from the thyristor switches, the contacts of these control circuits are turned on, and the three-stage upper heater 19-5 and the first-stage upper heater 19 are connected. -1 comes to be supplied with a voltage of 200V.

Further, the selected lower heat power supply path drives the lower heat power supply path relay 15-3, and the relay 15-3
The lower heat heater relay 13-3 and the lower heat heater relay 13-1 are operated via the contacts.

As a result, the lower heat heater relay 13-3
The relay contact x 13 of the lower heat heater and the relay contact x 11 of the lower heat heater relay 13-1 are turned on, and the temperature regulator 1-6 of the lower heat heater of the three stages and the temperature regulator 1 of the lower heat heater of the first stage 1
The control circuits 4-6 and 4-2 receive the signal voltage from 2 and the contacts of those control circuits are turned on, and the three-stage lower-heat heater 19-6 and the one-stage lower-heat heater 19-2 are turned on.
It comes to be supplied with a voltage of 00V.

In this way, the rotary switch 7 for the upper fire and the rotary switch 8 for the lower fire advance every time the input signal from the oscillator 6 is present, and circulate so as to sequentially switch the power feed paths, The upper heater 19-provided in each stage of the firing furnaces a-1, a-2, and a-3 depending on the degree of advance.
1.19-3.19-5 and lower heat heater 19-2.
19-4 and 19-6 are sequentially switched to energize them. And the upper heater 19-1, 19-3, 19
-5 and lower heat heater 19-2, 19-4, 19-6
In each case, the interval of the signal oscillated from the oscillator 6 is 7
If it is seconds, the operation of turning on for 14 seconds, which is twice that of 7 seconds, and turning off for 7 seconds is repeated, and the temperature of each firing furnace is raised.

At this time, the output voltages of the temperature controllers 1-1 to 1-6 of the upper heater and the lower heater of each stage are supplied to the upper heater via the relay driving units 3-1 to 3-6. Each of the search relays 18-1, 18-3, 18-5 and the lower heat search relays 18-2, 18-4, 18-6 is driven, and the A contacts of the relays are circulated over the upper heat feed line. The relays 14-1, 14-2, 14-3 and the lower heat feeding path relays 15-1, 15-2, 15-3 are in a conductive state with the respective A contacts, and are for switching between high speed and low speed via the operation power source. The drive relay 16 and the drive relay 17 are turned on, so that the drive relay 16 and the drive relay 17
The contact is turned off and the oscillation operation of the oscillator 5 is held in a stopped state.

Next, when the temperature in the firing furnace of each stage reaches the set temperature set in each temperature controller 1-1 to 1-6 by the above-mentioned operation, the signal voltage of each temperature controller is changed. Output stops. As a result, the upper fire search relays 18-1, 18-3,
18-5 and lower heat search relay 18-2, 18-4.1
Each search relay of 8-6 stops driving, each A contact of the upper heat search relay and the lower heat search relay, and the circulating upper heat power supply path relays 14-1, 14-2, 14-3 and the lower heat. The power supply path relays 15-1, 15-2, 15-3 are not electrically connected to the respective A contacts, and the drive relay 16 and the drive relay 17 for switching between high speed and low speed are turned off. B contact of is turned on,
The oscillator 5 starts oscillating. As a result, the rotary switch 7 for the upper fire and the rotary switch 8 for the lower fire are switched to the high-speed orbiting state by the signal oscillated from the oscillator 5 for the high speed.

In this state, each temperature controller 1-1 to 1
Since the control circuits 4-1 to 4-6 each made up of a thyristor switch controlled by −6 are turned off, the rotation of the rotary switch 7 for upper fire and the rotary switch 8 for lower fire causes Relay contact × 1 ・ × 11 ・ ×
Even if 2 · × 12 · × 3 · × 13 is turned on, power is not supplied to the upper heat heater 19-1, 19-3, 19-5 and the lower heat heater 19-2, 19-4, 19-6. Not done. Then, when one of the temperature controllers 1-1 to 1-6 for controlling the upper heater and the lower heater which outputs a signal voltage due to the temperature decrease of the firing furnace, the temperature controller is output. When the upper heat rotary switch 7 or the lower heat rotary switch 8 selects the power supply path of the upper heat heater or the lower heat heater controlled by 1,
By the operation of the B contact described above, the oscillator 6 returns to the state in which the rotary switch 7 for upper heat and the rotary switch 8 for lower heat are returned to the state in which the oscillator 6 is connected to the power supply path selected according to the input signal from the oscillator 6. Supply power to the fire heater or bottom heater.

Therefore, the operation of the rotary switch 7 for the upper fire and the rotary switch 8 for the lower fire controlled by the high-speed oscillator 5 is carried out at a high speed by rotating the electric heater of the firing furnace whose temperature has dropped below the set temperature. Only the electric heaters searched will be searched and power will be supplied.

[0052]

As described above, in the temperature control device for a firing furnace in a multi-stage electric oven according to the present invention, each power feeding path of an electric heater incorporated in each of the firing furnaces arranged in multiple stages is provided with a rotary switch. In this way, one of the power supply lines is sequentially switched and selected to be controlled to be turned on, and the operation of each electric heater is detected by the temperature sensor provided in each firing furnace. Is controlled to be turned off when the temperature reaches the set temperature set in the temperature controller, and the advance rate of the rotary switch is set so that all the temperatures in the furnaces of the firing furnaces arranged in multiple stages are equal to each other. The speed is controlled to reach the set temperature set by the controller, and the speed is controlled to lower by setting the firing temperature below the set temperature among firing furnaces arranged in multiple stages. Therefore, in the preliminary operation to raise the temperature of all firing furnaces to the set temperature, reverse the ratio of the total capacity of the electric heaters installed in series and the capacity of one electric heater selected from those electric heaters. Although it will take a long time proportionally, after all the firing furnace temperatures have reached the set temperature, the firing furnaces that have fallen below the set temperature are searched for and the electric heaters installed in that firing furnace are searched. Only after a certain period of time, power will be supplied at fixed intervals, so even after the electric heater is turned off, the temperature of the hearth including the electric heater does not shift to the high temperature side. As a result, the temperature inside the baking furnace during the baking work can be delicately controlled, and the confectionery and bread can be baked into good quality ones.

[Brief description of drawings]

FIG. 1 is an overall block circuit diagram of a temperature control device for a firing furnace in a multi-stage electric oven according to the present invention.

FIG. 2 is a block circuit diagram up to a portion indicated by symbol (a) in the circuit diagram of FIG.

FIG. 3 is a block circuit diagram of a portion below the portion indicated by symbol (B) in the circuit diagram of FIG.

[Explanation of symbols]

a ... Baking furnace, 1 ... Temperature controller, 2 ... Widening device, 3 ... Relay drive unit, 4-1 to 4-6 ... Control circuit consisting of thyristor switch, 5 ... High speed self-oscillator, 6 ... Low speed Self-oscillator, 7 ... rotary switch for upper heat, 8 ... rotary switch for lower heat circle, 9 ... upper heat relay drive unit, 10 ... lower heat relay drive unit, 11 ... changeover switch, 12-1, 12-
2 / 12-3 ... Relay of upper heat heater, 13-1 / 13
-2.13-3 ... Lower Heater Relay, 14-1.1
4-2 ・ 14-3 ... Up fire power supply line relay, 15-1 ・ 15
-2.15-3 ... Lower fire power supply line relay, 16.17 ... Drive relay, 18-1,18-3,18-5 ... Upper fire search relay, 18-2,18-4,18-6 ... Lower Fire search relay,
19-1, 19-3, 19-5 ... Upper heater, 19-
2.19-4, 19-6 ... Lower heat heater.

Claims (2)

[Claims] 1. Built into firing furnaces arranged in multiple stages
Each feed path's electric heat heater, a rotary switch, and controls so going to turn sequentially selects one one from among them feedline, each conductive
The temperature of the heating heater is set in each firing furnace.
A setting that sets the temperature in the furnace detected by the sensor to the temperature controller.
The temperature is controlled to turn off by reaching a constant temperature, and the rotation speeds of the rotary switches are set so that the temperatures in all of the firing furnaces arranged in multiple stages reach the set temperature.
Therefore, the rotation speed becomes high, and the rotation speed becomes low when the firing furnaces with the above-mentioned set temperature or less are released in the firing furnaces arranged in multiple stages .
A method for controlling the temperature of a firing furnace in a multi-stage electric oven, which is characterized in that it is controlled as described above . 2. A plurality of firing furnaces are arranged side by side, and the firing furnaces are arranged in parallel.
Each built-in electric heating heater, and those electric heating
-The power supply line of the
A rotary switch that sequentially selects and turns on one power supply line.
Each drive circuit of the electric heater
The temperature of each firing furnace is set in the temperature controller.
There is a control circuit that turns off the power when the temperature reaches the set temperature.
Connect each one, and the rotary switch
Adjust the angular velocity so that all temperatures in each firing furnace reach the set temperature.
Use the and to increase the speed and set the firing temperature below the set temperature in each firing furnace.
Connected an oscillator that controls the speed to be low
Baking furnace in a multi-stage electric oven characterized in that
Temperature control device.