JPH0429935B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a temperature control device for a vaporizer in a vaporization type combustor, and in particular, the present invention relates to a temperature control device for a vaporizer in a vaporization type combustor. The present invention relates to a temperature control device for a vaporizer that controls the limit temperatures on the high temperature side and the low temperature side.

[Technical background of the invention and its problems] For example, in a vaporizing fuel device used as a type of hot air heater for home use, the fuel in the fuel tank is vaporized by a vaporizer, and the vaporized fuel is Burn it in the combustion chamber. The air heated by this combustion heat is then blown as hot air into the room to be heated by an air blower. In order to improve the fuel combustion efficiency in such a vaporization type combustor, it is necessary to control the temperature of the vaporizer to a substantially constant value to efficiently vaporize the fuel supplied from the fuel tank.

Such a temperature control device for a vaporizer is configured as shown in FIG. 5, for example. One end of a thermistor 1 as a temperature sensor attached to a vaporizer (not shown) is grounded via a voltage dividing resistor 2, and the other end is connected to a DC +Vc power supply terminal. The voltage at the connection point between the thermistor 1 and the voltage dividing resistor 2 is applied to each of the three comparison circuits 3, 4, and 5 as a temperature detection voltage.
input to the side input terminal. Each comparison circuit 3, 4, 5
The voltage at the connection point of each of the four voltage dividing resistors 7, 8, 9, and 10 for generating a reference voltage, which are inserted between the +Vc power supply terminal and the ground, is input to one side input terminal. There is. That is, the comparator circuit 3 receives the limit voltage corresponding to the high temperature limit temperature Th, the comparator circuit 4 receives the set voltage corresponding to the set temperature Ts, and the comparator circuit 5 receives the low temperature limit temperature Tl. The limit voltage corresponding to is input.
The output signals of the comparison circuits 3, 4, and 5 are respectively input to the control circuit 6. Although not shown, a heater for heating the vaporizer is attached to the vaporizer.

If you have a temperature control device configured like this,
When the vaporizer temperature T detected by the thermistor 1 during combustion in the vaporizer combustor exceeds the set temperature Ts as shown in FIG. 6, the output signal of the comparator circuit 4 changes,
The control circuit 6 operates to cut off power to the heater. Even when the heater is shut off, the temperature T does not drop immediately due to residual heat, but drops after reaching a temperature slightly higher than the set temperature Ts. And the set temperature Ts
When it falls below, the output signal of the comparator circuit 4 changes again,
The control circuit 6 operates to start energizing the heater again. When the heater starts energizing, the temperature T is the set temperature
It rises after reaching a temperature slightly lower than Ts. When the temperature T of the vaporizer exceeds the high-temperature limit temperature Th for some reason, and the low-temperature limit temperature
When the temperature falls below Tl, the output signals of the comparison circuits 3 and 5 change, and the control circuit 6 operates to cut off the electricity to the heater and stop the fuel supply to the carburetor to extinguish combustion.

However, the vaporizer temperature control device constructed as shown in FIG. 5 has the following problems. That is, in addition to the comparison circuit 4 for detecting the set temperature Ts, two extra circuits are used to detect the high temperature limit Th and the low temperature limit Tl.
Since it is necessary to provide two comparison circuits 3 and 5, the number of electronic components increases, including the voltage dividing resistors 8 and 10 for generating the reference voltage, and there is a risk that the manufacturing cost of the entire temperature control device will increase. .

[Objective of the Invention] The present invention has been made based on the above circumstances, and its purpose is to measure the elapsed time after cutting off and starting energization of the heater, thereby determining the power of the comparator circuit. It is an object of the present invention to provide a temperature control device for a vaporizer in a vaporization type combustor, which can reduce the number of uses and reduce the manufacturing cost of the entire device.

[Summary of the Invention] In the temperature control device for a vaporizer in a vaporization type combustor of the present invention, the temperature of the vaporizer heated by a heater is detected by a temperature sensor, and this detected temperature is set in a preset setting. When the temperature rises to the set temperature, the energization to the heater is cut off, and the first timing means starts counting the elapsed time from the energization cutoff time, and when the temperature falls to the set temperature, the energization to the heater is started. When the second timer starts measuring the elapsed time from the energization start time and the temperature exceeds the set temperature when the first timer measures the predetermined first set time, and When the timer means measures a second preset time and the temperature falls below the set temperature, an extinguishing command for the entire vaporizing combustor is output.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a temperature control device for a vaporizer in a vaporizing combustor according to an embodiment. 11 in the diagram
a, 11b are power wires connected to a 100 volt AC power source via a plug, and these power wires 11a,
A heater 13 attached to a carburetor (not shown) is connected between 11b and 11b via a contact 12a of a relay 12. One end of a contact 14a of another relay 14 is connected to the power supply line 11a, and this contact 14a
Between the other end and the power line 11b, there is an electromagnetic pump 15 for supplying fuel from the fuel tank to the carburetor, an ignition transformer 16 for igniting the fuel vaporized in the carburetor and introduced into the combustion chamber, and an ignition transformer 16 for igniting the fuel vaporized in the carburetor and introduced into the combustion chamber. Blower motor 1 that blows heated air into the room as warm air
7 are connected in parallel. In addition, the power supply line 11
A control circuit 18 for controlling the operation of each relay 12, 14 is connected between a and 11b.

As shown in FIG. 2, the control circuit 18 is composed of a microcomputer, and a CPU (central processing unit) 19 of this microcomputer is connected to a bus line 2 consisting of a data bus, an address bus, etc.
ROM2 that stores the control program through 0
1. RAM2 that stores data such as set temperature Ts
2. Controls an input port 23, an output port 24, a first timer 25 as a first timer, a second timer 26 as a second timer, and the like.

Further, one end of a thermistor 27 as a temperature sensor attached to a vaporizer (not shown) is connected to a voltage dividing resistor 2.
8, and the other end is connected to a DC +Vc power supply terminal 29. Thermistor 27
The voltage at the connection point between and the voltage dividing resistor 28 is inputted to the input port 23 via the A/D conversion circuit 30 as a temperature detection voltage. Further, a command signal output from the output port 24 is input to the relay drive circuit 31. This relay drive circuit 31 drives the drive coil 1 of each relay 12, 14 based on the input command signal.
Controls the drive current flowing through 2b and 14b.

A preset temperature is stored in the RAM 22.
In addition to Ts, as shown in Figure 4, thermistor 27
A first set time T ₁ from the time when the temperature T of the vaporizer detected at 1 rises to the set temperature Ts and the power supply to the heater 13 is cut off, and when the temperature T falls to the set temperature Ts. A second set time _T2 from the time when energization of the heater was started is stored. As shown in FIG. 4, the value of the first set time T ₁ is determined from the time when the heater 13 is cut off until the temperature T reaches a temperature slightly higher than the set temperature Ts and then decreases until it falls below the set temperature Ts again. The value is set to a value that is longer than the required time and shorter than the time required for the temperature to rise again and reach the established temperature Ts.
Similarly, the value of the _second elapsed time T2 is such that after the heater 13 starts energizing, the temperature T reaches a temperature slightly lower than the set temperature Ts, and then rises again to the set temperature Ts.
The temperature is set to a value that is longer than the time required to exceed the temperature Ts and shorter than the time required for the temperature to drop again and reach the set temperature Ts.

The CPU 19 of the microcomputer is configured to control the temperature of the vaporizer according to the flowchart shown in FIG. 3 after the vaporizing combustor is powered on and various initial processes are performed. That is, the detected voltage input from the thermistor 27 to the input port 23 via the A/D conversion circuit 30 is read as the temperature value T. The temperature T read at P1 and
The magnitude relationship with the set temperature Ts stored in the RAM 22 is checked, and if the temperature T is higher than the set temperature Ts, the energization state of the heater 13 is checked from the energization state of the drive coil 12b of the relay 12. If the power is still on, the first timer 25 is started to start measuring the first set time _T1 , and the relay 12 is sent to the relay drive circuit 31 via the output port 24.
Sends an open command. Relay drive circuit 31 that received this open command operates drive coil 1 of relay 12.
Since the drive current to 2b is cut off, the contact 12a of the relay 12 is opened and the power supply to the heater 13 is cut off.

After the operation to cut off the current to the heater 13 or when the heater 13 is already in the current cut off state, P2
Then, it is checked whether the first timer 25 has finished measuring the first set time _T1 stored in the RAM 22. When the measurement is completed, the first timer 25 stops measuring, and the measured value is cleared to zero. and
The temperature T of the vaporizer at the time when the measurement ends at P3 is read from the input port 23, and it is confirmed that this temperature T is lower than the set temperature Ts.

If the temperature T read at P1 is less than the set temperature Ts, check the energization state of the heater 13, and only when it is still in the cut-off state, start the second timer 26 and start the second timer 26.
At the same time, the relay ₁ is sent to the relay drive circuit 31 via the output port 24.
The second drive command is sent to start energizing the heater 13.

When the temperature T is below the set temperature Ts at P3 and
If the first set time T ₁ has not been reached at P2, it is checked at P4 whether the second timer 26 has finished measuring the second set time T ₂ stored in the RAM 22. When the measurement is completed, the second timer 26 stops measuring, and the measured value is cleared to zero.
Then, at P5, the temperature T of the vaporizer at the time when the measurement ends is read from the input port 23, and it is confirmed that this temperature T is equal to or higher than the set temperature Ts. When the temperature T is equal to or higher than the set temperature Ts at P5, and when the second set time _T2 has not been reached at P4, the process returns to the beginning of this flowchart and reads the next temperature T.

When the temperature T exceeds the set temperature Ts at P3 and when the temperature T falls below the set temperature Ts at P5,
It is determined that some abnormality has occurred in the temperature control system and the temperature control is no longer working properly, and the output port 2 is
4, a command to open the relays 12 and 14 is sent to the relay drive circuit 31. Therefore, the drive coils 12b, 14 of the relays 12, 14
Since the drive current to b is cut off, relays 12,
14 contacts 12a and 14a are opened, and power to the heater 13 of the carburetor, the electromagnetic pump 15 for fuel supply, the ignition transformer 16, and the motor 17 of the blower is cut off. As a result, the fuel supply is stopped and the evaporative combustor is extinguished.

If the temperature control device for the vaporizer of the vaporization type combustor is configured in this way, the time can be adjusted as shown in Figure 4.
When the power is turned on at t ₀ , contact 12 of relay 12
Energization of the heater 13 with the switch a closed is started, and the temperature T of the vaporizer increases. Note that until the temperature T reaches the set temperature Ts, the first and second timers 25,
Since the heater 26 is not activated, the power supply to the heater 13 is not cut off. At time t ₁ , temperature T is the set temperature
When the temperature rises to Ts, the contact 12a of the relay 12 is opened and the heater 13 is de-energized, and the first timer 25 starts measuring the first set time _T1 . After that, the temperature T becomes slightly higher than the set temperature Ts, and then decreases again at time t ₂ , the set temperature Ts
decreases to At time _t2, power supply to the heater 13 is started, and at the same time, the second timer 26 starts measuring the second set time _T2 . After time _t2 , the temperature T once drops to a value slightly lower than the set temperature Ts, and then rises again. It is confirmed that the temperature T at time _t3, which is the first set time _T1 elapsed from the time _t1 when the heater 13 was shut off, is equal to or lower than the set temperature Ts.

The temperature T exceeds the set temperature Ts again at time _t4 ,
The temperature T at time t ₅ , when the second set time T ₂ has elapsed from time t ₂ when the heater 13 was shut off, is the set temperature.
It is confirmed that it is Ts or higher.

Due to some factor, the temperature T becomes the set temperature at time _t1 .
If the heater 13 is not shut off even though Ts has been reached, the temperature T rises as shown by the dotted line A in the figure. However, at time _t3 , when the first set time _T1 has passed, the relays 12 and 14 are opened and the heater 13 and fuel supply are cut off, so that the temperature T of the carburetor reaches the high temperature limit temperature _TH . At that point, the evaporative combustor is extinguished.

Similarly, if the heater 13 fails and is not energized during combustion in the vaporizing combustor, the temperature T decreases as shown by the dotted line B in the figure. However, at time _t5 , when the second set time _T2 has passed, the relays 12 and 14 are opened and the heater 13 and fuel supply are cut off, so that the temperature T of the carburetor reaches the lower limit temperature T _L. At this point, the evaporative combustor is extinguished.

With the temperature control device for the vaporizer of the vaporization type combustor configured in this way, there is no need to provide each of the comparison circuits 3, 4, and 5 as in the conventional temperature control device shown in FIG. The manufacturing cost of the entire control device can be reduced.

In particular, the microcomputer shown in Figure 2 is 1
The above effects can be further improved by treating the chip microcomputer as a single electronic component.

Note that the present invention is not limited to the embodiments described above. In the embodiment, the first timer 2
Although the timer 5 and the second timer 26 are provided as independent components, they are incorporated into the RAM 22 as the first and second counters, and the first and second set times T ₁ and T ₂ are set using the clock signal of the CPU 19 itself. may also be measured. By doing so, it is possible to further improve the above-mentioned effects.

[Effects of the Invention] As described above, according to the present invention, the limit temperatures on the high temperature side and the low temperature side are controlled by measuring the elapsed time after the heater is cut off and the energization is started. Therefore, the number of comparison circuits used can be reduced, and the manufacturing cost of the entire vaporizer temperature control device in the vaporizing combustor can be reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a temperature control device for a vaporizer in a vaporizer combustor according to an embodiment of the present invention;
Fig. 2 is a control circuit diagram showing the main parts of the temperature control device, Fig. 3 is a flow chart showing the operation of the temperature control device, Fig. 4 is a temperature characteristic diagram showing the operation of the temperature control device, and Fig. 5 6 is a schematic configuration diagram showing a conventional temperature control device, and FIG. 6 is a temperature characteristic diagram for explaining the operation of the temperature control device. 3, 4, 5... Comparison circuit, 12, 14... Relay, 12a, 14a... Contact, 13... Heater,
15...Electromagnetic pump, 16...Ignition transformer, 1
8...Control circuit, 19...CRU, 22...
RAM, 23...Input port, 24...Output port, 25...First timer, 26...Second timer, 27...Thermistor, 30...A/D conversion circuit, 31...Relay drive circuit , T...Temperature, T _S
...Set temperature, T ₁ ...First setting time, T ₂ ...
Second set time.

Claims (1)

[Claims] 1. In a vaporizing combustor that burns fuel vaporized in a vaporizer, a heater that heats the vaporizer, a temperature sensor that detects the temperature of the vaporizer,
a heater energization cutoff means for cutting off energization to the heater when the temperature detected by the temperature sensor rises to a preset set temperature; a heater energization start means for starting energization to the heater at the time; a first timer for measuring the elapsed time from the heater energization cutoff time; and a second timer for measuring the elapsed time from the heater energization start time. and when the temperature detected by the temperature sensor exceeds the set temperature when the first timer measures a predetermined first set time, and the second timer measures a predetermined first set time, and means for outputting a command for extinguishing the entire vaporizing combustor when the temperature detected by the temperature sensor when measuring a second set time falls below the set temperature. A temperature control device for a vaporizer in a vaporizer combustor.