JPH0749238Y2 - Thermal baking equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a combustion apparatus that performs combustion operation by supplying combustion air together with fuel to a combustion section.

(Prior Art) For example, in a fan heater that uses kerosene as fuel, the carburetor is heated in response to the operation switch being turned on, and the electromagnetic pump is driven to supply kerosene to the carburetor and vaporize it.
The vaporized gas is supplied to the combustion section and the combustion motor is rotated to send combustion air to the combustion section, and the mixed gas of the vaporized gas and air is ignited and burned.

In a combustion device that needs to send combustion air to the combustion unit in this way, the rotation of the motor becomes unstable due to initial failure of the combustion motor or failure due to aging, etc., and the combustion air is not sufficiently sent. There is a risk of ignition failure such as explosion and ignition, which in turn causes a fire.

Therefore, conventionally, a wind pressure switch is provided in a ventilation air passage for the combustion air, and after a certain time (for example, 2 minutes) has elapsed since the combustion motor was energized in response to the operation switch being turned on, the wind pressure switch is activated. It judges whether it is operating by the wind pressure of, and if it is operating, it continues the combustion operation and carries out the ignition operation, and if it is not operating, the combustion operation is stopped, and explosion fire or fire due to lack of air Was prevented.

(Problems to be solved by the invention) However, in the conventional combustion apparatus of this kind as described above, the good / defective of the combustion motor is judged by the one-point control by the on / off operation of the wind pressure switch. After a certain period of time when the state of the switch was read, the amount of air increased and the wind pressure switch was turned on, but it was not possible to detect a defective motor whose start-up was delayed and which was unstable.

In addition, since it was not possible to determine whether the combustion motor was good or bad until a fixed time elapsed until the state of the wind pressure switch was read, it wasted time until the defective motor was detected.

Therefore, the present invention intends to provide a combustion device capable of efficiently and surely detecting a defect of a combustion motor in a short time to stop the combustion operation and further improving safety.

[Structure of the Invention] (Means for Solving the Problems) In the combustion apparatus of the present invention, the rotation speed detection circuit for detecting the rotation speed of the combustion motor and the rotation speed of the combustion motor are normally set immediately after the operation switch is turned on. A comparison circuit that compares the number of revolutions of the combustion motor detected by the number-of-rotations detection circuit with the set number of revolutions corresponding to the elapsed time every time a predetermined time elapses until the steady rotation during combustion is reached. A combustion control circuit that continues the combustion operation when the rotation speed of the combustion motor reaches the corresponding set rotation speed by this comparison circuit, and stops the combustion operation when the rotation speed of the combustion motor is insufficient. It is a thing.

(Operation) With a combustion device that takes such measures, the combustion motor is rotated every time a predetermined time elapses during the period immediately after the operation switch is turned on until the rotation speed of the combustion motor reaches steady rotation during normal combustion. The number of revolutions of the combustion motor detected by the number detection circuit is compared with the set number of revolutions corresponding to the elapsed time. As a result, if the number of revolutions of the combustion motor reaches the corresponding set number of revolutions, combustion operation is performed. Is continued, and if the set speed is insufficient, the combustion operation is stopped.

(Embodiment) An embodiment in which the present invention is applied to a fan heater using kerosene as a fuel will be described below with reference to the drawings.

FIG. 1 is a circuit configuration diagram of the device of the present embodiment, in which an AC power source 1 supplies an oil pump 4A for supplying a combustion motor 3 and kerosene in an oil storage tank to a carburetor through a normally open contact 2 of a relay described later. A pump drive circuit 4B for driving the is connected. A phototransistor 5 is connected to the input side of the pump drive circuit 4B.

Although not shown, a heater for heating the vaporizer, an igniter for igniting a mixed gas of vaporized gas and air in the combustion section, and the like are also connected to the AC power supply 1.

Further, a power source input terminal V _D of a microcomputer 6 as a combustion control circuit main body is connected to a DC voltage source + E obtained by rectifying and stabilizing the AC power source 1.

The DC voltage source + E is a series circuit of a thermistor 7 and a resistor 8 for detecting the room temperature, a variable resistor 9 and a resistor 10 for setting the room temperature.
And 11 and a series circuit of the operation switch 12 and the resistor 13 are connected, respectively.

The connection point between the thermistor 7 and the resistor 8 is connected to the AD conversion function input terminal A / D ₁ of the microcomputer 6, and the movable point of the variable resistor 9 is input to the microcomputer 6 with the AD conversion function. It is connected to the terminal A / D ₂ and the connection point between the operation switch 12 and the resistor 13 is connected to the input terminal K ₁ of the microcomputer 6.

Further, a PNP type in a rotation speed detection circuit 17 including a parallel circuit of a relay 14 and a diode 15 for driving the DC voltage source + E to open and close the normally open contact 2 and a hall element 16 for detecting rotation of the combustion motor 3. A series circuit including a transistor 18 and a resistor 19 and the a terminal of the hall element 16 are connected.

The output terminal D ₁ of the microcomputer 6 is connected to the parallel circuit of the relay 14 and the diode 15 via the inverter circuit 20, and the input terminal D ₂ is connected to the collector of the transistor 18.

In the rotation speed detection circuit 17, the base and emitter of the transistor 18 are connected via a resistor 22, and the base is connected to the collector of an NPN transistor 24 via a resistor 23. The base and emitter of the transistor 24 are connected via a resistor 25, and the base is connected to the b terminal of the Hall element 16 via a resistor 26. Further, the a terminal of the hall element 16 is connected through a resistor 27.
It is connected to the collector of the NPN transistor 28, the b terminal is connected to the collector of the transistor 28, and the c terminal is connected to the emitter of the transistor 28.

In addition, the output terminal T of the microcomputer 6 is a resistor
It is connected via 29 to a parallel circuit composed of a photodiode 30 and a resistor 31. The photodiode 30 is paired with the phototransistor 5.

FIG. 2 is a sectional view showing the structure of the combustion motor 3, in which a rotor (rotor) 43 is provided between a pair of stators (stators) 41, 42, and A rotating shaft 44 is rotatably attached to the center. Further, a plurality of magnets 45, 46 are attached to one side surface of the rotor 43, and a stator (in this case,
The Hall element 16 is attached to 42).

This Hall element 16 is a magnet when the rotor 43 rotates.
When 45 or 46 approaches, the transistor 28 in FIG. 1 is turned on by its magnetic force, and when it goes away, the transistor 28 is turned off. When the transistor 28 is turned on, the transistor 24 is turned off, the transistor 18 is turned off, and the input terminal D ₂ of the microcomputer 6 becomes low level. On the other hand, when the transistor 28 is turned off, the transistor 24 is turned on, the transistor 18 is turned on, and a current flows through the resistor 19 to generate a voltage, so that the input terminal D ₂ of the microcomputer 6 becomes high level. Therefore, in the microcomputer 6, it is possible to detect the number of revolutions of the combustion motor 3 by calculating the number of repetitions of the low level and the high level at the input terminal D _{2 by} the number of the magnets 45 and 46 and the constant time. Is.

Then, the microcomputer 6 has a DC voltage source +
When a DC voltage of a predetermined voltage is supplied to the power input terminal V _D by E, the built-in program is activated to control each part. Then, when the closing of the operation switch 12 is detected by the input of the input terminal K ₁ , the combustion operation is started. In this combustion operation, the heater (not shown) is energized to heat the carburetor, and the signal from the output terminal D _{1 is set} to a high level to energize the relay 14 to close the normally open contact 2 and the combustion motor 3 and Drives the motor drive circuit 4B. Then, kerosene is supplied to the carburetor by the oil pump 4A driven by the motor drive circuit 4B to be vaporized, and the vaporized gas is supplied to the combustion section, and the combustion motor 3 rotates to generate combustion air to the combustion section. The mixed gas of the vaporized gas and the combustion air is generated in the combustion section. Therefore, the microcomputer 6 drives the igniter to ignite the mixed gas after a certain period of time until the mixed gas is generated, and starts the combustion operation. After starting the combustion operation, the room temperature is input from the input terminal A / D ₁ , and the combustion amount is determined by calculating the difference from the set temperature input from the input terminal A / D ₂ . Then, the pump drive circuit 4B is controlled by changing the frequency of the signal from the output terminal T according to the combustion amount.
The fuel supply amount by the oil pump 4A is controlled to adjust the combustion amount.

Further, the microcomputer 6 executes the combustion operation control routine shown in FIG. 3 in response to turning on of the operation switch 12. That is, turning on the operation switch 12 causes the input terminal K ₁
When it is detected by the input of, the built-in time counting timer is started. Then, when the time measured by the timer has passed t1 seconds, the number of revolutions of the combustion motor 3 detected by the input to the input terminal D ₂ is read, and this number of revolutions is preset corresponding to t1 time. Compare with the set number R1. When the number of revolutions of the combustion motor 3 is insufficient for the set number of revolutions, the signal output from the output terminal T is immediately stopped, and the relay 14 is de-energized to stop the above-mentioned combustion operation. .

On the other hand, when the rotation speed of the combustion motor 3 reaches the set rotation speed, the time measured by the timer is t2 (> t
1) When the number of seconds has passed, similarly, the rotation speed of the combustion motor 3 is set to a preset rotation speed corresponding to t2 time.
Compare with R2 (> R1). Then, when the rotation speed of the combustion motor 3 is insufficient to the set rotation speed, the above-described combustion operation is immediately stopped.

On the other hand, when the rotation speed of the combustion motor 3 reaches the set rotation speed, the time measured by the timer is t3 (> t
2) When the number of seconds has passed, similarly, the rotation speed of the combustion motor 3 is set to a preset rotation speed corresponding to t3 time.
Compare with R3 (> R2). Then, if the rotation speed of the combustion motor 3 is insufficient for the set rotation speed, the above-described combustion operation is immediately stopped, and if it has reached this control routine, this control routine is ended.

The set rotational speeds R1, R2, R3 (R1 <R2 <R3) are the lower limit values of the normal rotational speed of the combustion motor 3 at the corresponding clock times t1, t2, t3 (t1 <t2 <t3). .

In the present embodiment having such a configuration, the operation switch 12
When is turned on, the combustion operation is started, and the combustion motor 3 and the pump drive circuit 4B are activated. In addition, the time count by the built-in time count timer is started, and the rotation speed of the combustion motor 3 is detected by the output of the rotation speed detection circuit 17. In this state, the time measured by the timer is t1
When seconds have passed, the rotation speed of the combustion motor 3 at that time and
A preset rotational speed R1 (for example, 500 rpm) that is preset corresponding to t1 seconds is compared. Then, if the motor rotation speed reaches the set rotation speed R1, the combustion operation is continued, but if it is insufficient, it is determined that the combustion motor is defective and the combustion operation is stopped.

Here, if the combustion motor 3 is not judged to be defective and combustion operation is continued, when the time measured by the timer exceeds t2 seconds, the rotation speed of the combustion motor 3 at that time and t2 seconds are corresponded. Preset rotation speed R2 (for example, 1000rp
m) is compared with. Similarly, if the motor speed reaches the set speed R2, the combustion operation is continued, but if it is insufficient, it is determined that the combustion motor 3 is defective and the combustion operation is stopped. .

Here, if the combustion motor 3 is not determined to be defective and the combustion operation is continued, when the time measured by the timer exceeds t3 seconds, the rotation speed of the combustion motor 3 at that time and t3
The preset rotational speed R3 corresponding to the second (for example,
2000 rpm) is compared. If the motor rotation speed is lower than the set rotation speed R3, the combustion motor 3 is determined to be defective, and the combustion operation is stopped. On the other hand, if the set speed R3 is reached, it is determined that the combustion motor 3 is normal and the combustion operation is continued.

The relationship between the time counts t1, t2, t3 of the above-mentioned timer and the set rotational speeds R1, R2, R3 for the combustion motor 3 is shown by G in FIG. In addition, typical rotation speed rising characteristics of a normal combustion motor at 60 Hz and 50 Hz are shown in FIGS. Further, FIGS. 7C and 7D show the rotation speed rising characteristics of the combustion motor, which is defective because dust or the like is clogged between the stators 41 and 42 and the rotor 43.

When a combustion motor having a rising characteristic as shown in FIG. 6C is used, when the ignition operation is performed in response to the operation switch being turned on, the combustion air is so small that it extinguishes the suffocation.
At this time, if the combustion operation is not stopped, the combustion part is filled with the vaporized gas, and thereafter, the combustion motor normally rotates to explode and ignite when sufficient combustion air is fed.

On the other hand, when a combustion motor having a rising characteristic as shown in FIG.
Combustion air runs short because the rotation speed of the combustion motor does not increase. At this time, if the combustion operation is not stopped, an oil sump will be generated at the bottom of the combustion part, and the accumulated oil may be ignited to cause a fire.

Therefore, conventionally, as described above, the good / defective of the combustion motor is judged by observing the on / off of the wind pressure switch when a certain time has elapsed after the operation switch was turned on. Assuming that the motor rotation speed when turning on is about 2000 [rpm] and the fixed time is one-point control of t3 seconds, the combustion motor with the bad characteristic C cannot be detected and explosion ignition occurs. In addition, even a combustion motor having a poor characteristic D could not be detected until t3 hours had passed, and there was a risk of fire.

On the other hand, in the present embodiment, for a combustion motor having a bad characteristic C, it takes a short time after the operation switch is turned on.
At t1, the motor speed does not reach the set speed R1 (500 rpm), so it is determined to be defective and the combustion operation is stopped. For a combustion motor with a poor characteristic D, the motor speed is set at the time t2, which is shorter than the time t3.
Since it has not reached R2 (1000 rpm), it is determined to be defective and combustion operation is stopped.

Therefore, according to this embodiment, the microcomputer 6
Can be used to make a good / bad judgment of the combustion motor in multiple stages to make a judgment in accordance with the operation of the actual machine, and at the start of the combustion operation, the failure of the combustion motor 3 can be reliably and efficiently achieved in a short time. It can be detected well and the combustion operation can be stopped. As a result, there is no risk of explosion ignition or fire due to lack of air, and safety can be further improved. Further, the cost can be reduced because a relatively inexpensive Hall element is used without using an expensive wind pressure switch.

In the above-mentioned embodiment, the case where the control is performed only at the start of the combustion operation is shown. However, even during the steady state, the rotation speed of the combustion motor 3 is constantly monitored at the set rotation speed R3, so that the combustion motor after the steady state is It is possible to reliably detect the abnormality of item 3.

Further, in the above-described embodiment, the case where the rotation speed of the combustion motor 3 is detected by the detection circuit including the Hall element 16 is shown, but the present invention is not limited to this, and other circuit configurations may be used. Needless to say. Further, the number of magnets attached to the rotor 43 may be one. Further, in the above-described embodiment, the case where the present invention is applied to the fan heater using kerosene as a fuel has been described, but it is needless to say that the present invention can be applied to any combustion device that supplies combustion air together with fuel to the combustion section for combustion.

[Advantages of the Invention] As described in detail above, according to the present invention, it is possible to detect the rotation failure of the combustion motor immediately after the operation switch is turned on efficiently and surely and stop the combustion operation. It is possible to provide a combustion device that can improve safety without the risk of explosion ignition or fire due to lack of air.

[Brief description of drawings]

1 to 4 are views showing an embodiment of the present invention. FIG. 1 is a circuit configuration diagram of a combustion device, FIG. 2 is a sectional structure diagram of a combustion motor, and FIG. 3 is a microcomputer. FIG. 4 is a flow chart showing the combustion operation control routine in FIG. 4, and FIG. 4 is a diagram for explaining the function and effect of this embodiment. 3 ... Combustion motor, 4A ... Pump drive circuit, 4B ... Oil pump, 6 ... Microcomputer, 12 ... Operation switch, 16 ... Hall element, 17 ... Rotation speed detection circuit, 41, 4
2 …… stator, 43 …… rotor, 45,46 …… magnet.

Claims (1)

[Scope of utility model registration request] 1. A rotation system for detecting the number of rotations of a combustion motor in a combustion apparatus for supplying fuel to a combustion part by turning on an operation switch and supplying combustion air by rotating a combustion motor. A number detection circuit and a period from immediately after the operation switch is turned on until the rotation speed of the combustion motor reaches a steady rotation during normal combustion,
A comparison circuit that compares the number of revolutions of the combustion motor detected by the number-of-revolutions detection circuit with a set number of revolutions corresponding to the elapsed time each time a predetermined time elapses, and the comparison circuit A combustion device, comprising: a combustion control circuit that continues combustion operation when the rotation speed reaches a corresponding set rotation speed, and stops the combustion operation when the rotation speed falls short of the set rotation speed.