JP2000018579A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve safety upon use by judging to the utmost any failure of combustion operation. SOLUTION: The present apparatus includes a first thermocouple 17 for outputting a larger electromotive force as temperature of a combustion flame from a burner 3 becomes higher, and control means C for interrupting combustion of the burner 1 when it judges any failure of combustion operation based upon detection information of the first thermocouple 17. Herein, the control means C judges any failure of the combustion operation based upon an increased state of a detected value by the first thermocouple 17 as combustion continuation time is passed during set time is elapsed since initiation of the combustion operation of the burner 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromotive force generating means for outputting an electromotive force which increases as the temperature of a combustion flame of a burner increases, and determines abnormality of a combustion operation based on detection information of the electromotive force generating means. Then, the present invention relates to a combustion device provided with control means for stopping combustion of the burner.

[0002]

2. Description of the Related Art In the above-described combustion apparatus, for example, a thermocouple is conventionally used as the electromotive force generating means, and at the start of the burner combustion operation, the electromotive force output from the electromotive force generating means generates a combustion flame. Since it takes a predetermined time to increase to an appropriate electromotive force corresponding to the temperature, the control means sets the time until the set time (for example, about 60 seconds) elapses after starting the combustion operation of the burner. Further, the abnormality determination of the combustion operation based on the detection information of the electromotive force generating means is not executed.

[0003]

In the above-described conventional configuration, it is not possible to determine the abnormality of the combustion operation until the set time elapses after the start of combustion of the burner. Even in the case where an abnormality in the combustion operation has already occurred, for example, in an incomplete combustion state in the operation, the burner combustion operation is performed until the set time elapses. Will be.

[0004] Therefore, when the burner starts burning in a state where the above-mentioned abnormality of the combustion operation has already occurred, the burner is started despite the abnormality of the combustion operation already occurring. There is a disadvantage that the combustion operation is performed until the set time has elapsed, and there is room for improvement.

The present invention has been made in view of such a point, and an object of the present invention is to provide a combustion apparatus capable of improving safety in use by determining abnormality of a combustion operation as quickly as possible. The point is to provide.

[0006]

According to a feature of the present invention, the control means controls the combustion continuation time from the start of the combustion operation of the burner to the lapse of a set time. An abnormality in the combustion operation is determined based on a state in which the detection value of the electromotive force detection means increases with time.

When the combustion of the burner is started, the temperature of the combustion flame of the burner is high, so that the detection value of the electromotive force generating means increases. At this time, for example, in a normal combustion operation state of the burner, Assuming that there is a case and a case where the burner has already experienced an abnormality in the combustion operation, the detection value of the electromotive force detection means increases as the combustion continuation time elapses according to the difference between those situations. There will be differences. For example, in a normal combustion state, the detected value of the electromotive force rapidly increases, and the value when the detected value is stabilized increases. On the other hand, when an abnormality occurs in the combustion operation, the detected value of the electromotive force may increase more slowly and to a smaller value than in a normal case.

Therefore, at the start of combustion of the burner, it is possible to determine an abnormality in the combustion operation based on the increase in the detection value of the electromotive force detection means. In this way, by burning the burner in the abnormal state of the combustion operation as soon as possible to determine the abnormality of the combustion operation and stop the combustion of the burner, it is possible to shorten the time for burning the burner in the abnormal state of the combustion operation and improve the safety in use. Reached.

According to a second aspect of the present invention, in the first aspect, the control means is configured such that the combustion continuation time elapses from the start of the combustion operation of the burner to the elapse of the set time. The electromotive force discrimination level is set so as to sequentially increase as the power consumption increases, and when the value detected by the electromotive force generation means falls below the electromotive force discrimination level, it is determined that the combustion operation is abnormal. ing.

That is, when the combustion of the burner is started, it is heated by the combustion flame of the burner and the detection value of the electromotive force generating means gradually increases. At this time, an abnormality in the combustion operation has occurred. At this time, since the detection value of the electromotive force is slower to increase than in the normal combustion state, the detection value set by the electromotive force generation means is set so as to gradually increase as the combustion duration time elapses. This is below the power determination level, and it is determined that the combustion operation is abnormal.

Therefore, since the discrimination processing is executed by simply comparing the electromotive force discrimination level with the detection value by the electromotive force generating means, for example, the change rate (differential value) of the detection value is calculated. The control configuration for discrimination becomes simpler than a configuration or the like in which the obtained change rate is compared with a preset change rate.

According to a third aspect of the present invention, in the first or second aspect, after the set time has elapsed, the control means may determine that a value detected by the electromotive force generation means corresponds to a steady combustion operation. If the level falls below the set electromotive force determination level for steady operation, it is determined that the combustion operation is abnormal.

In the steady combustion state, the value detected by the electromotive force generation means becomes a substantially constant and stable value. Therefore, when the level falls below the predetermined electromotive force determination level for the steady operation corresponding to the steady combustion operation, the combustion operation is started. It is determined that it is abnormal. Therefore, the abnormality of the combustion operation can be properly determined with a simple configuration.

According to a fourth aspect of the present invention, in the first aspect, the control means includes a means for generating the electromotive force during a period from the start of the combustion operation of the burner to a lapse of the set time. If the rate of change of the detection value on the increase side is smaller than a set value, it is determined that the combustion operation is abnormal.

When the combustion of the burner is started, it is heated by the combustion flame of the burner, and the detection value of the electromotive force generating means gradually increases. Since the detection value of the electromotive force is slower to increase than in the normal combustion state, the rate of change on the increase side of the detection value by the electromotive force generating means becomes smaller than the set value, and it is determined that the combustion operation is abnormal. Will be.

Therefore, the state of increase in the value detected by the electromotive force generating means is directly determined based on the rate of change on the increasing side.
For example, as compared with a configuration in which a determination level that changes over time is set and the determination level is compared with the detection value of the electromotive force generating means, the increase state can be determined more appropriately.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the heat exchanger heated by the burner is provided on an upper part of a cylinder body forming a combustion chamber of the burner, The electromotive force generating means includes a first thermocouple that outputs a higher electromotive force as the temperature of the combustion flame of the burner is higher, and a first thermocouple that outputs a higher reverse electromotive force as the ambient temperature in the combustion chamber is higher. 2 thermocouples are provided, the first thermocouple and the second thermocouple are connected in series, and the total value of the output of the electromotive force in each thermocouple is input to the control means. The control means is configured to determine an abnormality in the combustion operation based on the increasing state of the total value.

For example, when the combustion products and dust are clogged between the heat exchangers due to long-term use and the exhaust passage is closed, the ambient temperature in the combustion chamber becomes high.
The thermocouple will generate a large reverse electromotive force.
That is, the total value of the outputs of the thermocouples fluctuates depending not only on the combustion state of the burner but also on the state of exhaust gas blockage.

As a result, at the start of burner combustion,
Based on the increase in the total value of the outputs of the thermocouples, it is possible to appropriately determine not only the abnormality of the combustion state of the burner but also the abnormality of the exhaust blockage.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where a combustion device according to the present invention is applied to a water heater will be described below with reference to the drawings. First, the overall configuration of the hot water supply device will be described with reference to FIG. A fin tube type heat exchanger for water heating 2 is provided at the upper end inside the cylinder 1, a burner 3 for heating the heat exchanger 2 is provided below the cylinder 1, and the burner 3 is provided inside the cylinder 1. A combustion chamber R is formed. Water supply channel W to heat exchanger 2
i, a water shutoff valve 4, a water governor 5 for adjusting a water supply amount in response to a change in water pressure, and a diverter valve 6 are provided. A hot water outlet Wo from the heat exchanger 2 is connected to a flexible pipe 7 And is connected to the tapping tool 8 via. The gas supply path G to the burner 3 is connected to the water governor 5 via the shut-off valve 9 and the interlocking rod 10a in response to a water pressure responsive valve 10 that opens only in a water supply state, and in response to a change in the original pressure of the fuel gas supply. A gas governor 11 for maintaining the fuel gas supply pressure to the burner 3 at an appropriate pressure, and an adjustment valve 12 for adjusting the fuel gas supply amount are provided. The shunt valve 6
The amount of water supplied to the heat exchanger 2 and the amount of bypass water to be separately supplied from the water supply channel Wi to the hot water channel Wo via the bypass channel Wb are adjusted. Further, a controller C is provided as a control means including a microcomputer for performing various controls of the hot water supply device.

Next, the control operation of the controller C at the time of tapping and stopping water will be described. When the tapping-type tapping operation tool 13 is pressed to tap the tap, the operation microswitch 14 is pressed.
Is turned on, and at the same time, the water stop valve 4 is opened in conjunction with the pushing operation of the tapping operation tool 13, the water enters the water governor 5, and the interlocking rod 10a opens the water pressure responsive valve 10 by the water pressure. In response, the hydraulic micro switch 15 is turned on. When the operation microswitch 14 and the hydraulic microswitch 15 are turned on, the controller C causes the spark plug 16 to spark and causes an adsorption current to flow through the coil 9a of the shutoff valve 9, so that the shutoff valve 9 is opened. Therefore, the fuel gas is supplied to the burner 3 through the shut-off valve 9, the water pressure responsive valve 10, the gas governor 11, and the regulating valve 12 opened by the interlocking rod 10a responsive to the water pressure, and supplied to the burner 3, and ignited by the spark of the spark plug 16. Being burned. The first thermocouple 17 is provided in contact with the combustion flame of the burner 3, and is attracted from the controller C to the coil 9 a of the shut-off valve 9 by the electromotive force of the first thermocouple 17 heated by the combustion flame of the burner 3. The current continues to flow, and the opening of the shutoff valve 9 continues. On the other hand, the water flows through the water stop valve 4, the water governor 5, and the flow dividing valve 6, flows into the heat exchanger 2, and at the same time, flows through the bypass path Wb to the hot water path Wo. Then, the hot water from the heat exchanger 2 and the water from the bypass passage Wb are mixed, and the hot water at an appropriate temperature is discharged from the tapping tool 8.

When the tapping operation tool 13 is pressed in the tapping state to stop water, the water stop valve 4 is closed and water supply is stopped in conjunction with the pushing operation, so that the water governor 5 has no water pressure difference. The interlocking rod 10a responds in a direction to close the hydraulic pressure responsive valve 10, the hydraulic pressure responsive valve 10 is closed, the fuel gas supply to the burner 3 is cut off, and the combustion of the burner 3 is stopped. With the pushing operation of the tapping operation tool 13 in the tapping state described above,
Operation micro switch 14 and hydraulic micro switch 1
When the switch 5 is turned off, the controller C stops flowing the adsorption current to the coil 9a, so that the shut-off valve 9 is closed.

Next, with reference to FIG. 1, a description will be given of the configuration of the safety means that is executed when an abnormality such as a combustion abnormality occurs in the burner 3 or an exhaust blockage of the heat exchanger 2 occurs. The above-described first thermocouple 17 that outputs an electromotive force according to the temperature of the combustion flame of the burner 3 and the second thermocouple that outputs an electromotive force having a polarity opposite to that of the first thermocouple 17 according to the temperature of the combustion chamber R. 2
A thermocouple 21, a temperature fuse 19 near the nozzle that blows when the temperature near the gas nozzle 18 becomes abnormally high, and a tube that blows when the temperature near the outer periphery of the cylindrical body 1 becomes abnormally high. A body thermal fuse 20 is provided.

The first thermocouple 17 uses a metallic thermocouple mounting plate so that the heat-sensitive portion is located inside the combustion flame in a normal combustion state, and the plus side thereof is electrically connected to the thermocouple mounting plate. It is provided to be connected. The second thermocouple 21 is
The heat sensing portion is provided so as to face a temperature measurement opening 1 a formed in the cylinder body 1.

The thermal fuse 19 for the vicinity of the nozzle and the thermal fuse 20 for the cylinder body have the same configuration, and although not shown, a fuse element having lead wires connected to both ends thereof is made flexible and heat resistant. The temperature fuse 19 for the vicinity of the nozzle is located below the gas nozzle 18 corresponding to the burner 3 while being inserted into the tube and having the outer periphery of the tube bound with a binder and fixed in the tube. The temperature fuse 20 for the cylinder body is arranged in the vicinity of the rear side of the outer peripheral portion of the cylinder body 1 (the wall surface side when the hot water supply device is installed on a wall surface).

As shown in FIG. 2, the negative terminal of the first thermocouple 17 and the temperature fuse 1 for the vicinity of the nozzle are used.
9. Each of the cylinder body thermal fuse 20 and the minus terminal of the second thermocouple 21 are connected in series, and the plus terminal of the first thermocouple 17 and the minus terminal of the second thermocouple 21 are connected to the controller C, respectively. They are connected to input terminals a and b. In other words, the total value Vt of the electromotive forces of the thermocouples 17 and 21 is input to the input terminals a and b so that the second thermocouple 21 has an electromotive force having a polarity opposite to that of the first thermocouple 17. Make up.

Then, the controller C includes the first thermocouple 1
7, and the second thermocouple 21
It is configured to determine the operation abnormality based on the detection information of the electromotive force due to. More specifically, for example, in a steady combustion state, the controller C causes the total value Vt (input between the input terminals a and b) as shown in, for example, FIG. When the electromotive force becomes lower than the steady-state electromotive force determination level Vst, it is determined that the operation is abnormal, and the flow of the attraction current to the coil 9a of the shutoff valve 9 is stopped, and the shutoff valve 9 is closed. Thus, the combustion of the burner 3 is stopped.

If the amount of the primary air for combustion sucked from the receiving port 32 becomes abnormally small, or if the oxygen concentration in the primary air for combustion abnormally decreases, the burner 3 causes incomplete combustion and the combustion flame is generated. become longer. If the burner 3 causes such incomplete combustion as an operation abnormality to prolong the combustion flame or unexpectedly extinguish the combustion flame, the first burnout may occur.
When the electromotive force V1 of the thermocouple 17 decreases, as shown in FIG. 3A, the total value Vt decreases and falls below the electromotive force determination level Vst for steady operation. C closes the shut-off valve 9 and sets the burner 3
Supply of fuel gas to the burner 3 is stopped, and the combustion of the burner 3 is stopped.

Further, when the combustion products and dust in the combustion gas adhere to the heat exchanger 2 and the combustion gas passage of the heat exchanger 2 becomes narrow, the amount of the combustion gas remaining in the combustion chamber R increases. hand,
The ambient temperature in the combustion chamber R increases. Due to such exhaust blockage, the ambient temperature in the combustion chamber R increases, and high-temperature combustion gas flows out of the temperature measurement opening 1a, and as shown in FIG. Although V2 becomes large, the electromotive force V2 has the opposite polarity to the electromotive force V1 of the first thermocouple 17, so that the total value Vt becomes small. When the ambient temperature in the combustion chamber R becomes abnormally high, the total value Vt falls below the electromotive force determination level Vst for steady-state operation. Closes the shut-off valve 9 to stop the combustion of the burner 3.

The atmosphere temperature in the combustion chamber R abnormally rises due to the adhesion of the combustion products and dust in the combustion gas to the heat exchanger 2, and the temperature near the outer periphery of the cylinder 1 is increased. When the temperature becomes abnormally high, the temperature fuse 20 for the cylinder body is blown.
Further, a spider's web or dust accumulates in the receiving port 32 of the burner 3, and a part of the fuel gas ejected from the gas nozzle 18 leaks out of the receiving port 32, and the leaked gas governor 3 When the temperature in the vicinity of the gas nozzle 18 becomes abnormally high due to ignition or burning by the combustion flame, the nozzle-use temperature fuse 19 is blown. When the temperature fuse 20 for the cylinder body is blown or the temperature fuse 19 for the vicinity of the nozzle is blown in this way, the total value (electromotive force input between the input terminals a and b) becomes substantially zero, The controller C closes the shut-off valve 9 to stop the burner 3 from burning.

In this hot water supply apparatus, the first thermocouple 17 operates not only in the steady combustion state as described above, but also in a transitional operation state from the start of combustion of the burner 3 to the elapse of a set time. An operation abnormality is determined based on the detection information of the electromotive force.

For example, when the combustion of the burner 3 is started, the combustion chamber R is already in an oxygen-deficient state at that time. Immediately after the start of the combustion, the burner 3 lifts, for example, and the combustion state becomes unstable. It is possible that
Such an abnormality in the combustion operation is determined to avoid disadvantages such as unnecessary burning of the burner 3 in the abnormal operation state.

That is, the controller C determines whether the value of the detected value of the first thermocouple 17 has increased with the lapse of the combustion duration from the start of the combustion operation of the burner 3 to the lapse of the set time. Thus, an abnormality in the combustion operation is determined. More specifically, during the period from the start of the combustion operation of the burner 3 to the elapse of the set time, the electromotive force determination level is set so as to gradually increase as the combustion duration time elapses. When the total value Vt falls below the electromotive force determination level, it is determined that the combustion operation is abnormal. still,
Immediately after the start of the combustion, the ambient temperature in the combustion chamber R hardly rises, so that the detection value of the second thermocouple 21 can be considered to be almost zero, and the total value Vt at this time is , Can be considered to be substantially the same as the electromotive force of the first thermocouple 17.

More specifically, as shown in FIG. 4, after the first set time t1 (for example, about 3 to 4 seconds) has elapsed since the combustion of the burner 3 was started, as shown in FIG. From the start of combustion to the elapse of the second set time t2 (for example, about 10 to 15 seconds), if the electromotive force discrimination level is normal, a higher electromotive force is already generated in the normal combustion state. The first setting level Vs1 is assumed to be set. Then, after the time t2 has elapsed from the start of combustion, the combustion state of the burner 3 and the first
The stabilization elapsed time tn as the set time at which the electromotive force of the thermocouple 17 is predicted to reach a stable steady combustion state.
Until the elapse of (for example, about 60 seconds), the electromotive force determination level is higher than the first set level Vs1 and if the combustion state is normal, a higher electromotive force is already generated. Second setting level Vs assumed to be present
Set to 2. After the elapse of the stabilization elapsed time tn, the electromotive force determination level Vst for the steady operation corresponding to the steady combustion operation is set. It should be noted that the symbol Vt in FIG.
The line indicated by (OK) indicates a change in the detected value (the total value) of the electromotive force in the normal combustion state, and the line indicated by the symbol Vt (NG) in FIG. The change of the detected value of the electromotive force when it occurs is shown. In addition, after the combustion of the burner 3 is started, the erroneous determination may be performed until the first set time t1 elapses. Therefore, the above-described electromotive force level determination operation is not performed.

As described above, as the electromotive force discrimination level sequentially increases with the lapse of the burning duration, the output of the thermocouple also gradually increases immediately after the combustion of the burner 3 is started. Even during a short period, the combustion operation of the burner 3 can be stopped as early as possible by appropriately determining the abnormality of the combustion operation, and the safety in use can be improved.

[Other Embodiments] (1) In the above embodiment, three levels are set as the electromotive force discrimination level. However, the present invention is not limited to such three levels, and is not limited to the three levels until the set time elapses. , Four or more levels may be set so as to sequentially increase as the combustion duration elapses, or two levels of a discrimination level for steady-state combustion and an intermediate level smaller than the discrimination level may be set. It may be.

(2) In the above-described embodiment, the structure for judging an increase in the detection value of the first thermocouple (electromotive force detecting means) as the combustion duration time elapses is determined. While the electromotive force discrimination level is sequentially increased, it is determined that the operation is abnormal when the detected value of the first thermocouple falls below the electromotive force discrimination level. It may be configured as follows.

That is, if the rate of change of the value detected by the electromotive force generating means on the increasing side is smaller than the set value during the period from the start of the burner combustion operation to the elapse of the set time, the combustion operation of the burner is started. The configuration is such that it is determined to be abnormal. More specifically, when the combustion of the burner is started, the detection value of the first thermocouple is sequentially increased by the heating of the combustion flame of the burner. If the amount of increase, that is, the slope of the increase in the detected value is smaller than a preset value, it is determined that the operation is abnormal. With this configuration, it is possible to more accurately detect the operation abnormality.

(3) In the above embodiment, the first thermocouple 17 and the second thermocouple 21 are connected in series, and only the total value of the electromotive force is input to the controller. Although the detection value of the first thermocouple is determined by the value, instead of such a configuration, for example, as shown in FIG. 5, both ends of each of the thermocouples connected in series and an intermediate connection point are connected. Electrically connected to a controller C (control means), and the total value of the output of the electromotive force in each thermocouple;
The output value of the electromotive force of the first thermocouple 17 may be configured to be input, or, as shown in FIG.
7 and the second thermocouple 21 are electrically connected in parallel to a controller C (control means) so that an electromotive force can be separately detected.
7 and the detection information of the electromotive force by the second thermocouple 21 may be obtained separately.

(4) In the above-described embodiment, the temperature fuse 19 for the vicinity of the nozzle and the temperature fuse 20 for the cylinder body are provided to further enhance the safety in use. You may.

(5) In the above embodiment, the case where the specific configuration of the combustion apparatus to which the present invention is applied is a hot water supply apparatus is illustrated. However, the specific configuration of the combustion apparatus can be variously changed.
For example, a heating device may be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a hot water supply apparatus to which the present invention is applied.

FIG. 2 is a control block diagram.

FIG. 3 is a diagram showing an electromotive force generation state;

FIG. 4 is a diagram showing an electromotive force generation state;

FIG. 5 is a circuit diagram showing a connection state of a thermocouple of another embodiment.

FIG. 6 is a circuit diagram showing a connection state of a thermocouple of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Heat exchanger 3 Burner 17 1st thermocouple 21 2nd thermocouple C Control means R Combustion chamber tn Setting time

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuharu 1-52 Oka, Minami-shi, Minato-ku, Osaka-shi, Osaka F-term in Harman Co., Ltd. (reference) 3K003 SA02 SB01 SB02 SC03

Claims (5)

[Claims] An electromotive force generating means for outputting an electromotive force that increases as the temperature of a combustion flame of a burner increases, and an abnormality in a combustion operation is determined based on detection information of the electromotive force generating means.
Control means for stopping the combustion of the burner, wherein the control means, from the start of the combustion operation of the burner until the set time has elapsed, the combustion continuation time A combustion device configured to determine an abnormality in the combustion operation based on a state in which the detection value of the electromotive force detection means increases as time passes. 2. The control means sets the electromotive force discrimination level such that the electromotive force discrimination level increases gradually as the combustion continuation time elapses from the start of the combustion operation of the burner to the elapse of the set time. 2. The combustion apparatus according to claim 1, wherein the combustion device is configured to determine that the combustion operation is abnormal when a value detected by the electromotive force generation means falls below the electromotive force determination level. 3. The control unit according to claim 1, wherein after the set time has elapsed, when a value detected by the electromotive force generation unit falls below an electromotive force discrimination level for a steady operation set corresponding to a steady combustion operation, 3. The apparatus according to claim 1, wherein the combustion operation is determined to be abnormal.
A combustion device as described. 4. The control means, if the rate of change of the value detected by the electromotive force generating means on the increasing side is smaller than a set value between the start of the combustion operation of the burner and the elapse of the set time. 2. The combustion device according to claim 1, wherein the combustion device is configured to determine that the combustion operation is abnormal. 5. A heat exchanger heated by a burner is provided on an upper part of a cylinder body forming a combustion chamber of the burner, and the electromotive force generating means increases the temperature of the combustion flame of the burner as the temperature increases. A first thermocouple that outputs electric power, a second thermocouple that outputs a larger electromotive force in the opposite direction as the ambient temperature in the combustion chamber is higher is provided, and the first thermocouple and the second thermocouple are provided. Are connected in series,
The total value of the output of the electromotive force in each of the thermocouples is configured to be input to the control unit, and the control unit is configured to determine an abnormality in the combustion operation based on the increasing state of the total value. Claim 1
5. The combustion device according to any one of 4.