JPH0727479A - Control method of vacuum heating-dryer - Google Patents

Abstract

PURPOSE:To properly detect an abnormal event such as a leakage from a container and a mis-heating by monitoring changes with time in pressures inside a container and exhaust gas temperatures. CONSTITUTION:A control circuit 100, to which a treatment start switch 4, a treatment stop switch 5, a pressure sensor 7 and a temperature sensor 8 are connected, receives and recognizes operating input information and measuring information from component parts. An exhaust time measuring timer 21 of the control circuit 100 measures time period of exhaust operation by a vacuum pump 17 within a specified period, and a heating time measuring timer 22 measures heating time periods every time a magnetron is operated. According to those information, the control circuit 100 monitors changes with time in pressures inside a container and exhaust gas temperatures. Thereby, an abnormal event such as a leakage from the container and mis-heating can be properly detected, and safety can be ensured by automatically, quickly stopping an apparatus when an abnormal event is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a vacuum heating / drying apparatus, and more particularly to a vacuum method for drying raw garbage in a finite closed space such as a spaceship, a submarine, an aircraft, etc. The present invention relates to a control system of a heating / drying device or a control system of a vacuum heating / drying device for drying an organic substance (including food) or an inorganic substance at the above-mentioned location.

[0002]

2. Description of the Related Art Conventional vacuum heating and drying apparatuses using microwaves are disclosed in JP-A-61-211201, JP-A-61-211202, and JP-A-62-1941.
Apparatuses described in Japanese Patent No. 81 and Japanese Patent Laid-Open No. 4-80585 are known.

In the above-mentioned JP-A-61-211201 and JP-A-61-211202, the apparatus is activated by a microwave switch attached to the lid of a microwave shielding container (hereinafter sometimes simply referred to as a container). Then, the magnetron is started at the stage when the vacuum gauge attached to the container is below the predetermined pressure, and then the magnetron is turned on and off according to the detection information from the temperature detector in the vacuum pipe.
It was configured to let.

Further, in the above-mentioned Japanese Patent Laid-Open No. 62-194181, when the magnetron is turned on and off based on the detection information from the temperature detector in the vacuum pipe, the magnetron is turned off from ON.
If the time to F exceeds a certain value, the device is stopped.

Further, in the above-mentioned Japanese Patent Laid-Open No. 04-080585, the vacuum exhaust is configured only for the inner container installed in the microwave shielding container.

[0006]

By the way, in the prior arts according to the above-mentioned prior applications, no consideration is given to leakage from the container, and even if a large amount of leakage occurs due to a hole or the like in the container. There was a serious problem that the abnormality of the device could not be detected.

In addition, in the above-mentioned prior art, no consideration is given to empty cooking, and the container does not contain the material to be dried, or the container contains the material to be dried that has been completely dried from the beginning. However, since the apparatus starts heating after reaching a predetermined vacuum degree and does not stop the heating operation until the exhaust temperature reaches a predetermined value, there is a problem that the apparatus overheats and is dangerous.

Furthermore, in the above-mentioned prior art, no consideration is given to the heating efficiency by the magnetron, and when the temperature difference between the temperature at which the magnetron is stopped and the temperature at which it is restarted is large, the ratio of heating by the magnetron is high. There was a problem that was small.

The present invention has been made in view of the above points,
The purpose of this is to detect the occurrence of a large amount of leak in the container, automatically stop the operation, and prevent the failure from spreading.

Another object of the present invention is to:
While detecting the exhaust temperature, identify the state that there is no dried object in the container, or the state that the dried object has been completely dried from the beginning in the container, that is, the empty cooking state, and identify it as empty cooking In such a case, the apparatus is promptly stopped to ensure safety, and when a material to be dried containing moisture is contained, the apparatus is operated until normal termination.

Still another object of the present invention is to increase the heating rate by the magnetron and improve the processing speed.

[0012]

Among the above-mentioned objects, in order to achieve detection of an abnormality of the device when a large amount of leak occurs in the container and prevention of expansion of the failure, Add a pressure sensor to the vacuum exhaust pipe,
A timer is added to the control device that controls the entire vacuum heating / drying device, and the control device determines whether or not a leak has occurred depending on how the exhaust pressure changes over time. The drive is controlled or stopped.

In addition, among the above-mentioned purposes, a temperature sensor is added to the vacuum exhaust pipe outside the microwave shielding container in order to distinguish the cooking state from the normal state and to safely drive or stop the apparatus. In addition, by adding a timer to the above control device, the control device determines whether or not the material to be dried containing water is contained in the microwave shielding container according to the information on the time change of the exhaust temperature. The drive is controlled or stopped according to the determination result.

Furthermore, in order to make it easier to distinguish between the above-mentioned cooked state and normal state, a heating frequency counter is added to the control device.

Further, among the above objects, in order to increase the heating rate by the magnetron and improve the processing speed, the temperature difference between the temperature at which the magnetron is stopped and the temperature at which it is restarted is optimized. Configured to do so.

[0016]

By adding a pressure sensor to the vacuum exhaust pipe outside the microwave shielding container and adding a timer to the control device that controls the entire vacuum heating / drying device, the control device has a function during the starting vacuum exhaust operation (at the time of starting). ) And the vacuum pumping operation accompanied by heating with a magnetron (during the operation after the operation is started), the vacuum pump monitors the change in the pressure applied to the material to be dried in the container by the information from the timer and the pressure sensor. Can be operated. Then, the control device determines that it is abnormal if the predetermined pressure is not reached (the pressure does not decrease to the predetermined pressure) even after a predetermined time elapses during the starting vacuum evacuation operation or during the vacuum evacuation operation accompanied by heating by the magnetron. At this time, when the starting vacuum exhaust operation is being performed, the control device immediately stops the operation operation of the entire device. Also, during the vacuum exhaust operation accompanied by heating by the magnetron, the control device stops the heating by the magnetron, continues the vacuum exhaust for a predetermined period, and lowers the exhaust temperature when the pressure does not drop below the predetermined pressure. After that, the operation of the entire device is stopped. Furthermore, the control device displays a warning in each case. This allows
Even if the lid is closed, if a large amount of leak occurs in the microwave shielding container, this can be detected as an abnormality. Therefore, it becomes possible to automatically stop the device before the failure spreads, and prevent the propagation of the failure.

Further, by adding a temperature sensor to the vacuum exhaust pipe outside the microwave shielding container and further adding a timer to the above-mentioned control device, after the predetermined pressure is reached, the control device is operated by the timer and the temperature sensor. It is possible to drive and control the magnetron while monitoring the change of the exhaust temperature by the information. Then, when the exhaust temperature does not rise even after the lapse of a predetermined time during the first heating, the control device determines that it is abnormal, stops the magnetron, and then confirms that the exhaust temperature has become sufficiently low, and then performs vacuum exhaust. Stop the operation of the entire device by stopping. As a result, it can be recognized that the microwave-shielded container does not contain a substance to be dried (moisture-containing), and the device can be safely stopped and a warning can be displayed.

On the other hand, after the predetermined temperature is reached, the control device controls the operation of the magnetron while monitoring the change of the exhaust temperature by the information from the timer and the temperature sensor.
At this time, the control device stops the heating by the magnetron and the time measurement by the timer at the time when the exhaust temperature reaches the boiling temperature of water at the ultimate vacuum in the container, and the exhaust temperature is changed from the boiling temperature above. After the temperature has decreased by the predetermined temperature difference, the heating by the magnetron and the time measurement by the timer are restarted. Further, in the case of not the first heating, if the exhaust temperature does not reach the boiling point temperature of water at the ultimate vacuum in the container even after a predetermined time has elapsed after restarting the magnetron, it is judged that the drying is completed and the magnetron is stopped. While the vacuum is being exhausted, the normal end is displayed, and after confirming that the exhaust temperature is sufficiently low, the operation of the entire device is stopped.
This makes it possible to safely end the operation of the device.

Further, by adding a heating frequency counter to the control device, it is possible to judge whether or not the heating is the first heating, and the control operation described above can be easily executed.

Further, the temperature at which the magnetron is stopped,
By optimizing the temperature difference from the restarting temperature, the heating rate by the magnetron can be increased and the processing speed can be improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to each embodiment shown in FIGS. FIG. 1 is a configuration diagram of a control system of a vacuum heating and drying apparatus according to the first embodiment of the present invention. In the figure, 1 is an outlet, 2 is a main power switch operated by an operator, 3 is a DC power supply for a control circuit, 4 is a process start switch operated by the operator, 5 is a process stop switch operated by the operator, and 6 Is a display device (eg, CRT display,
A display unit consisting of an LCD display, and 7 is an exhaust pipe (vacuum pump 17) outside a container (microwave shielding container) not shown.
To the pressure sensor, 8 is a temperature sensor also installed in the exhaust pipe outside the container (the conduit to the vacuum pump 17), 9 is a magnetron thermostat, 10 is a container thermostat, and 11 and 11 are Lid limit switch as a lid opening / closing detection sensor for detecting the open / closed state of the lid of the container, 12 main power relay, 13 magnetron drive relay, 14 vacuum pump drive relay, 15 high voltage power supply for magnetron, 16 inside container 1. A magnetron (microwave heater) for heating the material to be dried, a vacuum pump 17 for evacuating the inside of the container, and a magnetron cooling blower 18 for cooling the magnetron 16. Further, 100 is a control circuit that controls the overall control of the entire system (the entire vacuum heating / drying apparatus). In this embodiment,
An exhaust time measuring timer 21, a heating time measuring timer 22, and a heating frequency counter 23 are provided.

As shown in FIG. 1, the DC power source 3 for the control circuit is used.
The main power supply relay 12 is connected to the outlet 1 via the main power supply switch 2 (this can be omitted if unnecessary), and the control circuit power supply 3 is connected to the control circuit 100. The control circuit 100 includes a process start switch 4, a process stop switch 5, a pressure sensor 7, and a temperature sensor 8.
Are connected to the control circuit 100, and the control circuit 100 includes the constituent elements 4, 5, 7,
It receives the operation input information and the measurement information from 8 and recognizes this. A display unit 6 is connected to the control circuit 100, and the display unit 6 displays a message according to a signal from the control circuit 100.

The control circuit 100 and the main power supply relay 12 are
The signal line via the lid limit switch 11 and the other signal line are connected to each other, and the control circuit 100
Recognizes the open / closed state of the lid by the lid limit switch 11, and turns on the main power relay 12 as necessary.
OFF control. The main power supply relay 12 is connected to a magnetron drive relay 13 and a vacuum pump drive relay 14, respectively, the magnetron drive relay 13 is connected to a magnetron 16 via a magnetron high-voltage power supply 15, and the vacuum pump drive relay 14 is a vacuum pump. Pump 1
7 and a magnetron cooling blower 18, respectively. In addition, the control circuit 100 and the magnetron drive relay 13 are now connected to the signal line through the magnetron thermostat 9 and the container thermostat 10.
The control circuit 10 is connected by a book signal line.
0 recognizes the conduction state of the magnetron thermostat 9 or the container thermostat 10 and controls ON / OFF of the magnetron drive relay 13 as needed. Further, the control circuit 100 and the vacuum pump drive relay 1
4 is also connected, and the control circuit 100 controls ON / OFF of the vacuum pump drive relay 14 as needed. In this embodiment, the vacuum pump drive relay 14
When is turned on, the vacuum pump 17 and the magnetron cooling blower 18 are both driven.
The vacuum pump 17 and the magnetron cooling blower 18 may be driven and controlled independently of each other.

The exhaust time measuring timer 21 and the heating time measuring timer 22 of the control circuit 100 are the same as the control circuit 100.
The time counting operation and the resetting operation are controlled based on the control signal from the timer control unit of the exhaust time measuring timer 21.
Is for measuring the exhaust time by the vacuum pump 17 in a predetermined period, and the heating time measuring timer 22 is for measuring the heating time of the magnetron each time the magnetron is activated. The heating number counter 23 of the control circuit 100 is reset when the apparatus is activated, and counts the number of times a control signal is transmitted to the magnetron drive relay 13 to count the number of heatings by the magnetron.

In the above structure, when the outlet 1 and the main power switch 2 are turned on, electric power is supplied to the control circuit power supply 3 and the main power relay 12. As a result, the control circuit 100 is activated and the device (system) is in a standby state, and the control circuit 100 causes the display unit 6 to display a message indicating that it is in a standby state. By operating the processing start switch 4 in this state, the control circuit 100 is instructed to start control for performing vacuum heating and drying. As a result, the control circuit 100 executes the control process according to the flow shown in FIG. The operation of this embodiment will be described below with reference to FIG.

When the control start is instructed, the control circuit 100
First, the conduction state of the signal line connected from the lid limit switch 11 to the main power relay 12 is confirmed (step ST1), and it is determined whether or not the lid is closed (step ST2). If it is open, this fact is displayed on the display unit 6 (step ST9), and the subsequent operation is stopped. Further, when it is confirmed in step ST2 that the lid is closed, the control circuit 100 sends a relay contact connection command to the main power supply relay 12 to cause the main power supply relay 12 to first enter a conductive state. Then, next, a command for relay contact connection is sent to the vacuum pump drive relay 14 to make the vacuum pump drive relay 14 conductive, whereby the vacuum pump 17 and the magnetron cooling blower 18 are connected.
To start the vacuum evacuation operation (step ST
3). Simultaneously with the start of the exhaust, the exhaust time measuring timer 21 of the control circuit 100 is started to start measuring the time t from the start of the exhaust (step ST4).
The heating counter 23 is reset (step ST
5).

In the above state (after step ST5), the control circuit 100 monitors the exhaust pressure P from the object to be processed measured by the pressure sensor 7, and the time t from the start of exhaust by the exhaust time measuring timer 21. Then, it is determined whether or not the exhaust pressure P reaches the preset pressure P0 or less within a preset time t0 (steps ST7 and ST8), and if the determination is NO (NO), the container leak is large. After that, a command to open the relay contact is sent to the vacuum pump drive relay 14 to stop the exhaust operation (step ST8), and a message indicating that there is a leak is displayed on the display unit 6 (step ST9). Stop the entire driving operation. That is, the fact that the exhaust pressure P does not reach the preset pressure P0 or less within the preset time t0 after the start of exhaust means that the inside of the container is vacuum-exhausted with the lid closed. Nevertheless, it means that the intended depressurization operation has not been achieved, and it can be judged that the leak from the container is large. Therefore, even if the lid is closed, if a large amount of leak occurs in the container, this can be detected, this fact can be recognized by a message, and the device can be automatically stopped before the failure expands.

On the other hand, in steps ST7 and ST8,
When it is confirmed that the pressure P measured by the pressure sensor 7 reaches the preset pressure P0 or less within the preset time t0, the control circuit 100
Sends a relay contact connection command to the magnetron drive relay 13 to cause the magnetron 16 to start a heating operation via the magnetron high-voltage power supply 15 (step ST
10). As a result, the object to be processed is heated. By the start of this heating operation, the heating time measurement timer 22 of the control circuit 100 is started, and the time t ′ from the start of heating is started to be measured (step ST11), and the heating frequency counter 23 of the control circuit 100 causes the magnetron 16 to operate. Number of heatings by N
Is counted (step ST12). In this state, the control circuit 100 constantly operates the exhaust pressure P by the pressure sensor 7,
Exhaust temperature T and heating time measurement timer 2 by temperature sensor 8
A predetermined determination process is executed while monitoring the time t ′ from the start of heating by 2 (steps ST13, S
T14, ST15).

That is, in step ST13, when it is determined that the pressure P has risen to the pressure P0 or more due to the start of heating (NO in step ST13),
The control circuit 100 interrupts the heating by the magnetron 16 (step ST16) and resets the content of the exhaust time measurement timer 21 (step ST17),
Returning to step ST3, the operation is restarted from the state of starting the exhaust. This is because when a large amount of volatile components other than water vapor is generated from the material to be dried, it is necessary to depressurize the inside of the container again and then perform heating again from the beginning. Further, if a leak occurs due to some factor during the heating operation, after the heating is stopped, the steps ST6 and ST7 are performed.
This is because the leak is detected by the determination process in step S8, the warning is displayed in the process after step ST8, and the device is automatically stopped safely (this is done in step ST described later).
22 is also the same).

Even when the pressure P is kept below P0 by the start of heating (YES in step ST13), the exhaust temperature T is set to the preset time t1 from the start of heating in steps ST14 and ST15.
When it is determined that the preset temperature T1 (see FIG. 3) has not been reached (see FIG. 3) (step ST
If YES in 15), heating is stopped (step ST28), and after confirming that the exhaust temperature is sufficiently low (step ST29), exhaust by the vacuum pump 17 is stopped (step ST30). After this, the control circuit 1
00 indicates that the heating number N is 1 in step ST31.
The number of heating times N is 1 by asking whether it is (first heating).
In the case of (first heating), it is determined that the container does not contain the material to be dried, and the display unit 6 displays a message indicating that the object does not contain the material to be dried (step). ST9), the operation operation of the entire apparatus is stopped. What happens is that the exhaust temperature T does not reach the preset temperature T1 within a preset time t1 from the start of heating when the number of heating times N is 1 (first heating) means that the material to be dried is This is because it indicates that the exhaust gas temperature has not risen due to the generated steam, and it is determined that the cooking is done in the air. Therefore, the cooked state can be detected early in the operation start, the fact can be recognized by the message, and the device can be automatically stopped safely.

On the other hand, if it is determined in steps ST14 and ST15 that the exhaust temperature T has reached the preset temperature T1 within the preset time t1 from the start of heating (YES in step ST14). Proceeds to step ST18 and the heating number N is 1
If N = 1, the heating setting time ta is set to t2 (see FIG. 3) (step ST19), and if N is 2 or more, heating setting is performed. Time ta
Is set to t3 (see FIG. 3) (step ST20).
Then, next, the control circuit 100 determines that the exhaust temperature T reaches the ultimate vacuum degree in the container within the set time t2 or t3 and in the state where the exhaust pressure P is lower than the preset pressure P0. It is determined whether or not the boiling point temperature T0 of water in step S21 has been reached (steps ST21 and ST2).
2, ST23). When the exhaust pressure P becomes equal to or higher than the preset pressure P0 by this determination process (NO in step ST22), the control circuit 100 interrupts the heating by the magnetron 16 (step ST16) and measures the exhaust time. After resetting the content of the timer 21 (step ST17), the process returns to step ST3 to restart the operation from the state of starting the exhaust.

Further, steps ST21, ST22, ST2
When it is determined by the determination process of No. 3 that the exhaust temperature T does not reach the boiling point temperature T0 of water at the ultimate vacuum in the container within the set time (heating set time) t2 or t3 (step ST23). If YES, the control circuit 100 stops heating (step ST28),
After confirming that the exhaust temperature is sufficiently low (step ST2
9), the evacuation by the vacuum pump 17 is stopped (step ST30). Then, after this, the control circuit 100 asks in step ST31 whether or not the heating number N is 1 (first heating), and when the heating number N is 1 (in other words, the set heating setting is performed). (When the time is t2)
After determining that the cooking is due to any of the following factors, and displaying a message on the display unit 6 indicating that the cooking is due to any of the factors ,, (step ST
9) Stop the operation of the entire device. What if
When the heating number N is 1 (first heating), the exhaust temperature T
However, that the boiling point temperature T0 of water at the ultimate vacuum in the container does not reach within the set time t2 means that the material to be dried is not in the container, but a small amount of water exists in the container. Or, almost no steam was generated from the dried object, and the dried object which was almost completely dried was put in the container from the beginning, or the thermometer malfunctions due to noise or the like, and thus the steps ST14, ST15 This is because the case can be determined to be incorrect. Therefore, it is possible to detect leaks and empty cooking in which the dried material is almost completely dry in the container from the beginning, as well as empty cooking without the dried material. Can be recognized by a message, and the device can be automatically stopped safely.

On the other hand, the steps ST21, ST22,
The heating time t2 set by the determination processing in ST23
Alternatively, when it is determined that the exhaust temperature T reaches the boiling point temperature T0 of water at the ultimate vacuum in the container within t3 (YES in step ST21), the control circuit 100
Judges that the heating operation for a predetermined period is normally performed, and sends a command to open the relay contact to the magnetron drive relay 13 to stop the heating (step ST24). After that, when it is confirmed that the exhaust gas temperature T has dropped to the temperature T2 (step ST25), the control circuit 100 resets the content of the heating time measurement timer 22 (step ST26), and then starts heating again. At the same time, the content (number of times) of the heating number counter 23 is incremented by 1 (step ST27), and the process returns to step ST18. Then, by such an operation, the magnetron 16 is turned ON-O.
Heating and cooling are repeated by FF control. FIG. 3 shows the change over time of the exhaust temperature T at this time. In FIG. 3, when the exhaust temperature is increasing with time, the magnetron 16 is in the ON state, and when the exhaust temperature is decreasing with time, the magnetron 16 is off.
It is in a state.

Here, as the drying of the material to be dried progresses, the time during which the magnetron 16 is in the ON state gradually begins to increase, and at the end of the drying, the ON time of the magnetron 16 rapidly increases. Therefore, once the exhaust gas temperature T reaches the temperature T0, the heating time measurement timer 22 is reset each time heating is completed, and the number of times N of heating of the number-of-heating counter 23 is incremented by 1, and the above-mentioned is performed. Set the heating time to t
The time t ′ from the start of turning on the magnetron 16 is measured at each time. When the number of heating times N is 2 or more, in other words, the set time is t
In the case of 3, the above-mentioned steps ST21, S
When the measurement time t ′ exceeds the heating set time t3 by the determination processing of T22 and ST23 (step ST23 described above).
If YES, the control circuit 100 stops heating (step ST28), confirms that the exhaust temperature is sufficiently low (step ST29), and then the vacuum pump 17
The exhaust by is stopped (step ST30). Then, after this, the control circuit 100 proceeds to step S as described above.
At T31, it is asked whether or not the heating number N is 1 (first heating). In this case, since the heating number N is 2 or more, it is judged that the drying of the material to be dried is completed, and the display unit 6 is dried. After displaying a message that the process has been completed (step ST3
2) Stop the driving operation of the entire device and end the series of processes. By such processing, it is possible to cause the device to perform the drying processing and safely end the operation.

During the above process, the pressure P
However, when the pressure rises to P0 or higher, the heating is interrupted in any case, and the operation is restarted from the state of starting the exhaust. Furthermore, when it is detected by the magnetron thermostat 9 or the container thermostat 10 that the magnetron 16 or the microwave shielding container is in an overheated state, the magnetron 16 is immediately turned off,
Stop heating. When the lid limit switch 11 detects that the lid is open, the operation of the entire apparatus is stopped at that point. The two lid limit switches 11 are used as those having the functions of the processing start switch 4 and the processing stop switch 5 (the lid limit switch 11 that detects closure of the lid is used as the processing start switch 4 and the lid is opened). It is also possible to use the lid limit switch 11 for detecting the above as the process stop switch 5). Further, it is possible to use one of the lid limit switches 11 instead of the main power supply relay 12 and directly connect the other one of the lid limit switches 11 to the control circuit 100.

Further, the control circuit 100 described above may be one using a microprocessor, one using a comparator and a logic circuit, one using a thermometer with a temperature contact and a relay circuit, or a mixed circuit thereof. Can be configured. As the temperature sensor 8, any one can be used in combination with the control circuit 100 as long as it can generate a temperature signal or a temperature contact signal, such as a thermocouple, a resistance temperature detector, a thermistor, or a thermostat. Is. As the pressure sensor 7, any pressure sensor or pressure contact signal such as a semiconductor pressure sensor, a strain gauge pressure sensor, a spring pressure sensor, a pressure switch, or the like can be used. It can be used.

As described above in detail, according to this embodiment, a large leak has occurred in the container, or the container is in an empty cooked state with no material to be dried, or in the container. If it is determined that the dried material that has almost completely dried up is in the empty state that was put in from the beginning, and if these abnormalities are identified, the equipment is stopped immediately to ensure safety and A corresponding message can be displayed, and if there is no abnormality, the apparatus is operated until normal termination, so that a vacuum heating and drying apparatus with extremely high safety can be realized.

Here, FIG. 3 described above simulates a change in exhaust temperature predicted in an actual device. The exhaust gas temperature is approximately equal to the temperature of water contained in the material to be dried when the water vapor in the exhaust gas is evaporated. During heating, as the temperature rises, the vapor pressure of water at that temperature rises. As a result, the evaporation of water is activated, so that a large amount of latent heat of evaporation flows out together with the steam, and the temperature of the remaining water rises slowly. In addition, since there is no heat source after the end of heating, the evaporation of water, which was initially active, decreases as the temperature decreases (and therefore the vapor pressure of water decreases). Becomes slower. Therefore, as shown in FIG.
The temperature change in each heating state and each cooling state when heating-cooling is repeated has the largest change rate at the start of each state, and the change rate decreases with the passage of time. Therefore, the ratio during heating by the magnetron 16 is increased by reducing the temperature control width so that the temperature change indicated by the broken line is not the temperature change indicated by the solid line in FIG. That is, when the exhaust gas temperature T drops to T2 ′ after the heating is stopped, the heating is restarted to increase the ratio during heating by the magnetron 16.

It is obvious to those skilled in the art that the above-described control processing can be easily performed by setting the determination in step ST25 of FIG. 2 as T ≦ T2 ′. If the temperature control width is reduced in this way, the rate of heating by the magnetron 16 can be increased, and the drying processing speed can be improved.

In the above-described first embodiment described so far, the number of times the magnetron 16 is turned on and off is measured, and whether the number of times of heating is the first time or not is determined to be a comparison target of the measured heating time t '. Set the heating time to t
The method was changed to 2 or t3, and the method of distinguishing between the empty cooking and the end of processing was adopted. However, by comparing the measured heating time t ′ with the three parameters t1, t2, and t3 without measuring the number of times of heating, it is possible to distinguish between the idle cooking and the end of processing. Next, heating time t'is set to t1,
An example in which empty cooking and end of processing are distinguished by comparing with three parameters of t2 and t3,
This will be described with reference to FIGS. 4 and 5.

FIG. 4 is a block diagram of the control system of the vacuum heating and drying apparatus according to the second embodiment of the present invention. The present embodiment differs from the first embodiment of FIG. 1 in that the heating frequency counter 23 of the control circuit 100 is deleted from the configuration of FIG.
Further, FIG. 5 shows a control processing flow executed by the control circuit 100 of the present embodiment, and in FIG.
The process relating to the process of determining the number of times of heating in the process flow is deleted, and the heating time t ′ is set to 3 of t1, t2, t3.
A processing operation for comparing with one parameter is added.

As shown in FIG. 5, when the control start is instructed, the control circuit 100 first causes the lid limit switch 1
Check the open / closed state of the lid by 1 (step ST5
1) Based on this, it is determined whether or not the lid is closed (step ST52). If the lid is open, this is displayed on the display unit 6 (step ST58), and the subsequent operation is stopped. . When it is confirmed in step ST52 that the lid is closed, the control circuit 100 sends a command for relay contact connection to the main power supply relay 12, and first causes the main power supply relay 12 to transition to the conductive state. Then, next, a command for relay contact connection is sent to the vacuum pump drive relay 14 to make the vacuum pump drive relay 14 conductive, whereby the vacuum pump 17 and the magnetron cooling blower 1 are connected.
8 to start the vacuum exhaust operation (step S
T53). Further, at the same time when the exhaust is started, the control circuit 10
The exhaust time measurement timer 21 of 0 is started and starts measuring the time t from the start of exhaust (step ST54).

In the above state (after step ST54), the control circuit 100 monitors the exhaust pressure P and the time t from the start of exhaust, and the exhaust pressure P is preset within the preset time t0. It is determined whether or not the pressure P0 or less has been reached (steps ST55 and ST5).
6) If the determination is NO (NO), it is determined that the container leak is large, the evacuation operation by the vacuum pump 17 is stopped (step ST57), and a message indicating the leak is displayed on the display unit 6 ( In step ST58), the driving operation of the entire device is stopped.

On the other hand, in steps ST55 and ST56, when it is confirmed that the pressure P reaches the preset pressure P0 or less within the preset time t0, the control circuit 100 heats the magnetron 16. The operation is started (step ST59). By the start of this heating operation, the heating time measurement timer 22 of the control circuit 100 is started and starts measuring the time t ′ from the start of heating (step ST60). In this state, the control circuit 1
00 constantly executes a predetermined determination process while monitoring the exhaust pressure P by the pressure sensor 7, the exhaust temperature T by the temperature sensor 8, and the time t ′ from the start of heating by the heating time measurement timer 22 (steps ST61, ST62). ，
ST63).

That is, when it is determined in step ST62 that the pressure P has risen to the pressure P0 or higher due to the start of heating (NO in step ST61),
The control circuit 100 interrupts the heating by the magnetron 16 (step ST64) and resets the content of the exhaust time measurement timer 21 (step ST65),
Returning to step ST3, the operation is restarted from the state of starting the exhaust.

Even when the pressure P is kept below P0 by the start of heating (YES in step ST61), the exhaust temperature T is set to the preset time t1 from the start of heating in steps ST62 and ST63.
When it is determined that the preset temperature T1 (see FIG. 3) has not been reached (see FIG. 3) (step ST
In the case of YES in 63), the control circuit 100 determines that there is no substance to be dried in the container. Then, the control circuit 100 stops the heating (step ST75), confirms that the exhaust temperature is sufficiently low (step ST76), and then stops the exhaust by the vacuum pump 17 (step ST77). After displaying a message indicating that cooking is being performed (step ST58), the driving operation of the entire apparatus is stopped.

On the other hand, if it is determined in steps ST62 and ST63 that the exhaust temperature T has reached the preset temperature T1 within the preset time t1 from the start of heating (YES in step ST62). In the control circuit 100, when the exhaust pressure P is lower than the preset pressure P0 within a preset time t2, the exhaust temperature T is the water at the ultimate vacuum in the container. It is determined whether or not the boiling point temperature T0 of has reached (steps ST66, ST67,
ST68). By this determination processing, when the exhaust pressure P becomes equal to or higher than the preset pressure P0 (step ST
If NO in 67, the control circuit 100 interrupts the heating by the magnetron 16 (step ST).
64) After resetting the content of the exhaust time measurement timer 21 (step ST65), the process returns to step ST53 to restart the operation from the exhaust start state.

Further, steps ST66, ST67, ST6
When it is determined by the determination process of 8 that the exhaust temperature T does not reach the boiling point temperature T0 of water at the ultimate vacuum in the container within the preset heating time t2 (YES in step ST68). In the control circuit 100,
It is determined that the cooking is due to any of the above factors. Then, the control circuit 100 stops the heating (step ST75), confirms that the exhaust temperature is sufficiently low (step ST76), and then stops the exhaust by the vacuum pump 17 (step ST77). After displaying the message that the meal is cooked in the air (step S
T58), the driving operation of the entire apparatus is stopped.

On the other hand, steps ST66, ST67,
The heating time t2 set by the determination process of ST68
When it is determined that the exhaust temperature T has reached the boiling point temperature T0 of water at the ultimate vacuum in the container (step ST
If YES in 66), the control circuit 100 determines that the heating operation for the predetermined period is normally performed, and stops the heating by the magnetron 16 (step ST69). After that, the control circuit 100 determines that the exhaust temperature T is equal to the temperature T2.
When it is confirmed that the temperature has decreased to (or T2 ′) (step ST70), the contents of the heating time measurement timer 22 are reset (step ST71), and then heating is restarted (step ST72). Then, next, it is determined whether or not the exhaust temperature T has reached the boiling point temperature T0 of water at the ultimate vacuum in the container (step ST73), and if YES in step ST73, the process returns to step ST69 to perform heating. Stop and turn on the magnetron 16 by this loop.
Heating and cooling are repeated by FF control.

If NO at step ST73,
After confirming that the exhaust pressure P does not exceed the preset pressure P0 (step ST74), in step ST78, the measurement time t ′ from the restart of heating is the preset heating time t3 (or t3 ′). It is determined whether or not is exceeded. If NO in step ST78, the process returns to step ST73. On the other hand, if YES in step ST78, the control circuit 100 determines that the drying of the material to be dried is completed, and stops heating (step S78).
(T79), after confirming that the exhaust temperature is sufficiently low (step ST80), the exhaust by the vacuum pump 17 is stopped (step ST81), and a message indicating that the drying is completed is displayed on the display unit 6 (step ST82). , The operation of the entire device is stopped, and the series of processes is ended.

As described above, in this embodiment, in the first heating after the start of the vacuum evacuation, the measurement time t'is compared with the time t1 until the exhaust temperature T reaches T1, and the measurement time t. 'And the time t2 until the temperature T reaches T0 are compared with each other, and the cooked air (the cooked food in a state in which there is no material to be dried or water, the above-mentioned factors ,,
Each of the above) is detected. After the exhaust gas temperature T once reaches T0, the heating time timer 22 is reset when the exhaust gas temperature T cools to T2, and after the heating is restarted, until the measurement time t ′ and the temperature T reach T0. The end of processing is detected by comparing the time t3 of the above. As a result, in this embodiment as well, it is possible to determine whether the cooking is completed and the drying is completed, similarly to the first embodiment.

As described above, according to the present embodiment, the number of parts is reduced by removing the heating counter 23,
It has the effect of improving reliability.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram of the control system of the vacuum heating and drying apparatus according to the third embodiment of the present invention. As shown in FIG. 6, in the present embodiment, the main power switch 2 is omitted from the configuration of the second embodiment shown in FIG. 4 (addition can also be easily realized). Further, the main power supply relay 12 and the signal line connected to the main power supply relay 12 in FIG. 4 are deleted.
Along with this, from the control circuit 100 to the main power relay 1
The lid limit switch 11 added to the signal line connected to 2 is connected to the signal line from the control circuit 100 to the magnetron drive relay 13 and the signal line from the control circuit 100 to the vacuum pump drive relay 14, respectively. , At least one is connected at a time. Further, the pressure sensor 7 in FIG. 4 is omitted, and a pressure switch 71 (a switch that becomes conductive when P <P0) and a current sensor 72 are connected to two signal lines from the control circuit 100 to the magnetron drive relay 13. I connected each.

In this embodiment, since the pressure switch 71 does not pass through the control circuit 100, the time until the pressure P0 is reached cannot be measured in the operation after the start of vacuum evacuation. For this reason, the control circuit 100 constantly generates a command for relay contact connection to the magnetron drive relay 13, and the time t measured by the exhaust time measurement timer 21 is measured by the current instead of the time until the pressure P0 is reached. The measurement is performed by the time until the sensor 72 is energized. This is P in FIG.
<Achievable by replacing P0 with I ≠ 0. On the other hand, since the pressure switch 71 does not pass through the control circuit 100, when the pressure is around P0, it is possible to directly control the relay contact connection command to the magnetron drive relay 13. The operation of each part other than this is the same as the operation of the second embodiment shown in FIGS.

In this embodiment as well, similarly to the first embodiment shown in FIG. 1, the lid limit switches 11 and 1 are used.
1 may be used instead of the process start switch 4 and the process stop switch 5. Further, in the configuration of the present embodiment shown in FIG. 6, the main power switch 2, the main power relay 12, and the signal line connected to the main power relay 12 are installed in the same arrangement as in the second embodiment of FIG. It can be easily realized. Furthermore, the conditions for the control circuit 100 and the temperature sensor 8 are the same as in the first embodiment shown in FIG. Further, also in this embodiment, it is possible to add the heating number counter 23 to the control circuit 100 as in the first embodiment of FIG. This case can be achieved by replacing P <P0 in FIG. 2 with I ≠ 0.

According to the third embodiment shown in FIG. 6, the pressure switch 71 directly cuts off the magnetron drive relay 13 without passing through the control circuit 100, so that the safety against temperature control when the pressure rises is improved. There is an effect of doing.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a block diagram of the control system of the vacuum heating and drying apparatus according to the fourth embodiment of the present invention. As shown in FIG. 7, in the present embodiment, from the configuration of the second embodiment shown in FIG. 4, a main power supply relay 12 and a signal line connected to the main power supply relay 12, a magnetron thermostat 9, a container thermostat 10 are provided. And the temperature sensor 91 for a magnetron and the temperature sensor 101 for a container connected to the control circuit 100 are provided in place of the thermostat 9 for a magnetron and the thermostat 10 for a container in FIG. Further, the lid limit switch 11 in FIG. 4 is connected to the control circuit 100, and the control circuit 100 integrally controls all states. In such a configuration, the temperature sensor 91 for magnetron and the temperature sensor 101 for container can be the same kind as the temperature sensor 8.

The operation of this embodiment shown in FIG. 7 is the same as that of the first embodiment shown in FIG. 1 except that the control circuit 100 directly carries out all drive control of each part.

Also in this embodiment, the lid limit switch 11 can be used in place of the processing start switch 4 and the processing stop switch 5 as in the first embodiment shown in FIG. The main power switch 2 may be omitted in the present embodiment of FIG. 7 by adding the main power relay 12 and the signal line connected to the main power relay 12 in the same manner as in the second embodiment of FIG. It can be easily installed.
Furthermore, the conditions for the control circuit 100, the pressure sensor 7, and the temperature sensor 8 are the same as those in the first embodiment shown in FIG. It is also possible to add the heating number counter 23 to the control circuit 100 as in the first embodiment of FIG.

In the present embodiment, since all the state data are collected in the control circuit 100, there is an effect that the decision circuit for making a composite decision of each state data is common or simplified.

In each of the above-mentioned embodiments, any power source can be used as long as it can drive the magnetron and the vacuum pump. In addition, depending on the power source used, the main power relay 12, the magnetron drive relay 13, the vacuum pump drive relay 14
In addition to mechanical relays, semiconductor relays, etc., any type can be used as long as it can function as a switch that is opened / closed by an external signal and is suitable for the power source used. Further, the exhaust time measurement timer 21 and the heating time measurement timer 22 can be shared by one timer. Further, instead of the lid limit switch 11, it is possible to use a rotation detection sensor or the like attached to a portion that rotates when the lid is opened and closed. Also, as for the control flow, not only the control flow shown in FIG. 2 or FIG. 5, but also any control flow can be used as long as it can perform control equivalent to a series of processing operations in each embodiment. Is.

[0062]

As described above, according to the present invention, by monitoring the temporal changes in the pressure inside the container and the exhaust temperature, it is possible to prevent leaks in the container and empty cooking (no substance to be dried is contained in the container). It is also possible to accurately detect abnormalities such as that the dried material has been put in the container from the beginning), and if it is judged to be abnormal, safety is secured by automatically stopping the device immediately. In addition, when the object to be dried containing water is contained in the container, the apparatus is operated until the normal end, so that a highly reliable vacuum heating and drying apparatus can be realized, and its value is great.

Further, by decreasing the control temperature range, the heating rate by the magnetron can be increased, which has the advantage of improving the processing speed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a control system of a vacuum heating / drying apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a control processing flow executed by the control circuit of FIG.

FIG. 3 is an explanatory diagram showing an example of a change in exhaust temperature due to a vacuum heating / drying operation in each embodiment of the present invention.

FIG. 4 is a configuration diagram showing a configuration of a control system of a vacuum heating / drying apparatus according to a second embodiment of the present invention.

5 is a flowchart showing a control processing flow executed by the control circuit of FIG.

FIG. 6 is a configuration diagram showing a configuration of a control system of a vacuum heating / drying apparatus according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram showing a configuration of a control system of a vacuum heating / drying apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Outlet 2 Main power switch 3 Control circuit power supply 4 Processing start switch 5 Processing stop switch 6 Display 7 Pressure sensor installed in exhaust pipe 8 Temperature sensor installed in exhaust pipe 9 Magnetron thermostat 10 Container thermostat 11 Lid limit Switch 12 Main power supply relay 13 Magnetron drive relay 14 Vacuum pump drive relay 15 High voltage power supply for magnetron 16 Magnetron 17 Vacuum pump 18 Magnetron cooling blower 21 Evacuation time measurement timer 22 Heating time measurement timer 23 Heating counter 71 Pressure switch 72 Current sensor 91 temperature sensor for magnetron 100 control circuit 101 temperature sensor for container

Claims (9)

[Claims] 1. A microwave shielding container for containing a material to be dried, a vacuum pump for evacuating the inside of the microwave shielding container, and a magnetron (microwave heater) for heating the material to be dried in the microwave shielding container. ) And a vacuum heating / drying device having a basic configuration, a temperature sensor and a pressure sensor are added to the exhaust pipe outside the microwave shielding container, and a control device for controlling the overall vacuum heating / drying device is further added. A vacuum heating / drying apparatus, wherein a timer is added, and the control device stops the operation operation when it is determined to be abnormal based on the information from the temperature sensor, the pressure sensor, and the timer. Control method. 2. The control device according to claim 1, wherein the control device controls the timer and the pressure sensor during a starting evacuation operation before driving the magnetron and during an evacuation operation accompanied by a heating operation by the magnetron. The vacuum pump is drive-controlled while monitoring the change in pressure applied to the material to be dried in the microwave shielding container, and when the pressure does not reach the predetermined pressure after a predetermined time elapses, it is determined to be abnormal and the starting vacuum exhaust At the time of operation, immediately stop the driving operation of the entire device and display a warning,
Further, when the vacuum exhaust operation accompanied by the heating operation by the magnetron is being performed, the heating by the magnetron is stopped, the vacuum exhaust is continued for a predetermined period of time to reduce the exhaust temperature, and then the vacuum exhaust is stopped. A method of controlling a vacuum heating / drying device, characterized in that the operation of the entire device is stopped and a warning is displayed. 3. The exhaust system according to claim 1, wherein the control device changes the exhaust temperature of water vapor generated from the material to be dried in the microwave shielding container by the timer and the temperature sensor after reaching a predetermined pressure. While controlling the drive of the magnetron while monitoring the above, when the exhaust gas temperature does not rise to the predetermined temperature after the elapse of a predetermined time during the first heating, it is judged as abnormal and the magnetron is stopped, and then the exhaust gas temperature is sufficient. After confirming that the temperature is low, the vacuum exhaust is stopped to stop the operation of the entire apparatus, and a warning is displayed. 4. The exhaust system according to claim 3, wherein after the predetermined pressure and the predetermined temperature are reached, the control device drives and controls the magnetron while monitoring a change in exhaust temperature with the timer and the temperature sensor. When the temperature reaches the boiling temperature of water at the ultimate vacuum in the microwave shielding container, the heating by the magnetron and the time measurement by the timer are stopped, and the exhaust gas temperature is a predetermined temperature difference from the boiling temperature. After the temperature has dropped, heating by the magnetron and time measurement by the timer are restarted. 5. The temperature according to claim 1, wherein the magnetron and the timer are stopped,
By reducing the temperature difference with the temperature to restart,
A control system for a vacuum heating and drying apparatus, characterized in that a heating rate by the magnetron is increased. 6. The control device according to claim 4, wherein, in a case where the heating device is not the first heating device, the exhaust gas temperature is the ultimate vacuum degree in the microwave shielding container even after a predetermined time has elapsed after the magnetron is restarted. If it does not reach the boiling point temperature of water, it is judged that the drying is completed, the magnetron is stopped, and after confirming that the exhaust temperature is sufficiently low, the vacuum exhaust is stopped to stop the operation of the entire apparatus. At the same time, a method for controlling the vacuum heating and drying device is characterized by displaying the completion of drying. 7. The method of controlling a vacuum heating / drying device according to claim 1, wherein a heating number counter is added to the control device, and the number of heatings by the magnetron is counted. 8. A control system for a vacuum heating / drying device according to claim 1, wherein an opening / closing detection sensor is added to an opening / closing part of a lid of the device to provide a redundant system of a safety device. . 9. The vacuum heating / drying device according to claim 1, wherein a temperature sensor is added to the microwave shielding container and the magnetron to form a redundant system of a safety device. method.