JP3094615B2 - Combustion device soot clogging safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus such as a water heater using gas or petroleum fuel as a heat source, a heater for a hot water circulating heating device, a circulating heater for bathtub water, and a hot air circulating heater. The present invention relates to a device capable of obtaining safe operation when a heat exchanger for instantaneously passing and heating water or air is clogged with soot.

[0002]

2. Description of the Related Art Conventionally, a heat exchanger of a combustion appliance of this kind has
Incomplete combustion occurs when the burner starts and stops, such as when the burner starts and stops.Unburned carbon, etc. is emitted from gas or oil as fuel and adheres to the fins for absorbing heat absorbed by the heat exchanger to burn the burner. The condition was getting worse. Unburned carbon is also generated during combustion as so-called soot, soot clogging of fins and the like is accelerated, and the heat efficiency as a heat absorption rate of the heat exchanger is reduced. This decrease in the heat absorption rate causes the temperature of the combustion chamber of the heat exchanger to rise abnormally, and an overheating temperature detector is provided on the outer periphery of the side wall of the combustion chamber to detect the overheating temperature. I was taking.

[0003]

However, in the above configuration, when the overheated temperature detector detects an abnormality, it is already in a dangerous state for use, for example, the combustion chamber is locally damaged and the combustion gas overheats the parts in the appliance. Fire hazard.
For this reason, when the detection temperature of the over-temperature detector is lowered, there is a problem that the detection is performed erroneously even though the temperature is not abnormal, and a means for effectively avoiding danger due to soot clogging of the heat exchanger has been desired. .

Accordingly, the present invention provides a soot clogging safety device for a combustion apparatus, which can detect the degree of soot clogging before a danger due to soot clogging of a heat exchanger.

[0005]

Means for Solving the Problems In order to achieve the above-mentioned object, a first means of the soot clogging safety device for a combustion appliance according to the present invention comprises: an inlet water temperature detector for detecting an inlet water temperature to a heat exchanger; a burner for heating the water detector and the incoming water to detect the water flow rate, a fuel control means for adjusting the amount of fuel supplied to the burner, hot water detects the hot water temperature from the heat exchanger temperature detector and the hot water set temperature A setter, a combustion amount indicator for receiving signals from each of the detectors and the hot water setter, calculating a heating load of the heat exchanger, and outputting an instruction signal for fuel supply amount adjustment to fuel control means; plant calculates the thermal efficiency of the exchanger
The heat exchanger includes a soot clogging efficiency determiner that determines a degree of soot clogging of the combustion gas passage from the burner as compared with a fixed thermal efficiency .

[0006]

[0007]

[0008]

According to the first means described above, the soot clogging safety device for a combustion appliance according to the present invention is characterized in that the heat exchanger is in a state of soot clogging with unburned fuel in a combustion gas passage such as a fin for absorbing the combustion heat of the burner. Proceeds, the soot clogging efficiency determiner receives each detection signal from the incoming water temperature detector, the water amount detector, and the hot water temperature detector, and calculates the heat output of the heat exchanger. Further, the heat efficiency is calculated by dividing by the heat input corresponding to the heating load calculated when the combustion amount indicator indicates the fuel supply amount to the burner.

On the other hand, the soot clogging efficiency judging device is based on the experimental data of the heat efficiency according to the degree of clogging of the fins of the heat exchanger and the like. Stress, high-temperature oxidation, etc., causing high-temperature combustion gas to leak into other equipment from the heat exchanger due to cracks, breakage, etc. Has been entered. When the heat efficiency of the heat exchanger is calculated during the operation, the heat efficiency can be compared with the predetermined heat efficiency, and the predetermined heat efficiency can be detected before the danger is reached, and utilized for a notice, a warning, a prohibition measure, etc. according to the degree of soot clogging. And driving safety can be ensured.

[0010]

[0011]

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a safety device for combusting soot of a combustion appliance according to the present invention.

FIG. 1 shows, as one embodiment of the present invention, a water heater of an instant heating type using gas as a fuel, and a water supply passage 1 for receiving water from a water pipe or the like has a water amount detector 2 for detecting a flow rate of water supply, The apparatus is provided with an incoming water temperature detector 3 for detecting the temperature of supplied water, and supplies water to the heat exchanger 4. The heat exchanger 4 has a large number of fins 6 for absorbing the heat of combustion of the burner 5, a heating pipe 7 for instantaneously heating the feed water passing therethrough by brazing or the like, and a large space for burning the burner 5. And a discharge chamber 9 for collecting and discharging the combustion gas after heat transfer.

The gas passage 10 that receives gas supply as fuel from a gas supply pipe or the like has a proportional valve 11 that adjusts the gas supply proportionally on the way, and supplies fuel to the burner 5. The heat exchanger 4 that has heated the water supply supplies hot water to the hot water supply path 12, and the hot water supply path 12 detects the hot water temperature by the hot water temperature detector 1.
3. Hot water is supplied from a hot water tap 15 via a water flow control valve 14 for adjusting the flow rate of hot water.

The combustion air of the burner 5 is supplied from a blower fan 16 airtightly attached to the combustion chamber 8,
The rotation number 6 is detected by a rotation number detector 17. Proportional valve 11
And the like are electrically connected to the controller 18 as shown by the broken lines in FIG. The controller 18 has a blower fan 1
6, a drive circuit 19 as drive means for outputting a drive signal to the proportional valve 11, etc., a combustion amount indicator 20 for outputting an instruction signal to the drive circuit 19, and a fan drive current detection for detecting a fan drive current from the drive circuit 19 Current detection circuit 2 as a detector
1. An efficiency determination circuit 22 as a soot clogging efficiency determiner for determining soot clogging of the fins 6 and the like from the heat efficiency of the heat exchanger 4, and a soot clogging of the fins 6 and the like from a fan drive current corresponding to the rotation speed of the blower fan 16. A fan current determination circuit 23 and the like as a soot clogging current determination device are provided.

An operation panel 24 is also electrically connected to the controller 18. The operation panel 24 includes an operation switch 25 for instructing input of an external power supply to the controller 18, a hot water temperature display, a soot clogging abnormality of the heat exchanger 4, and the like. And a hot water temperature setting device 27 for setting the hot water temperature from the hot water tap 15.

Based on the above configuration, the principle that the heat absorbing operation of the heat exchanger 4 is hindered and deteriorated by soot clogging will be described first. FIG. 2 shows the heat exchanger 4 partially enlarged.
Heating pipe 7 has a large number of fins 6 by a furnace brazing process or the like at a narrow interval B _0. Then, the combustion gas G next to the combustion flame F of the burner 5 is hollow arrows, and passes through the narrow gap B ₀ of fins 6 applies heat q ₀ a large area S of the fins 6. The heat q ₀ is transmitted to the heating pipe 7 as heat q ₁ , and transfers the heat q ₂ to the water supply passing through the heating pipe 7 to process hot water. The burner 5 has a low flame temperature at the time of the point ignition for starting the combustion, at the beginning of the transition to the heating combustion, or at the time of the combustion stop, or incomplete combustion due to various unstable conditions such as a balance between the gas and the air. It passes through the fins 6 only by decomposing the carbon.

Then, as shown in FIG. 3, high-temperature combustion gas G is contained on the surfaces of the heating pipe 7 and the fin 6 having low surface temperature after passing through the low-temperature water supply, and the moisture generated by the combustion is condensed. Unburned fuel and decomposed carbon adhere to the place.
Further, the carbon charged at the time of decomposition has an electrical adhesive force. The deposits are heated by the combustion gas G. However, since the temperature condition is not sufficient to complete combustion, so-called incomplete combustion at the carbonization level is performed, and soot C is added to the fins 6 and the heating pipe 7 as shown in FIG. Adheres and deposits. Further, it is also deposited on other combustion gas passages such as the exhaust port 9a of the exhaust chamber 9.

The soot C gradually grows with the lapse of use time. For example, in the state shown in the figure, the combustion gas G does not directly apply heat to the fins 6 and the heating pipe 7, and the soot C as a poor conductor of heat transfer is removed. The combustion gas G is exhausted from the exhaust chamber 9 without sufficiently radiating heat, and the heat efficiency of the heat exchanger 4 is reduced. The degree of the decrease in the thermal efficiency is proportional to the thickness of the layer on which the soot C is deposited.

Further, when the soot C adheres to the fins 6 and the layer grows, the interval B through which the combustion gas G passes is narrowed.
The blower fan 16 has an increased ventilation resistance and reduces the amount of blown air. In other words, the blower fan 16 is controlled to a predetermined rotation speed by the drive circuit 19, but when the soot C increases, the work becomes smaller than in the clean operation, and the drive circuit 19
, The drive current value gradually decreases. For this reason, the air blowing amount is reduced with respect to the fuel supply amount of the proportional valve 11, and
The balance between fuel and air is lost, resulting in incomplete combustion of insufficient air, the burner 5 generates a large amount of carbon even during normal combustion for heating the feed water, and the soot C of the fins 6 increases with acceleration. Similarly, the number of the exhaust ports 9a increases.

When the fins 6 and the like are clogged with a large amount of soot C,
The combustion flame F of the burner 5 increases due to incomplete combustion.
The combustion chamber 8 in which a sufficiently large combustion space is set by preventing overheating due to the radiant heat of the combustion flame F has an increased combustion flame F, a reduced distance from the combustion flame F, and a heat reception amount proportional to the inverse square of the distance. Is significantly increased and overheated. In the combustion chamber 8 which receives overheating, a thermal stress is generated and an unreasonable force is applied to a processed portion or the like, so that a crack is generated. In addition, a material such as copper that has been overheated to a high temperature is deteriorated and abraded by high-temperature corrosion, and is partially lost and damaged. At the time of this phenomenon, the combustion gas G leaks from the cracked portion or the broken portion into the inside of the vessel, and there is a danger of damaging or igniting the synthetic resin coating and other combustibles of the signal line.

FIG. 4 is a graph in which the horizontal axis represents the level at which the soot C grows and the amount of deposit accumulates with the passage of time, and the vertical axis represents the heat exchanger 4.
3 shows a state in which the thermal efficiency of the fan or the drive current of the blower fan 16 changes. There is a slight decrease from the initial stage of use to the level Ca, but at the point b, the descending gradient Tb is considerably large, and the descending gradient Tc at the point c is extremely large. Point a is in a state where it can still be used but care must be taken for the accumulation of soot C.
At the point b, the thermal efficiency and the fan drive current thereafter deteriorate in an accelerated manner. Then, the point c is in a terminal stage , and the combustion chamber 8 is performing extremely dangerous combustion in which cracks and breakage occur. These points a, b, and c can be grasped with sufficient certainty based on past use results and experimental data.

Next, the operation of the efficiency judgment circuit 22 and the fan current judgment circuit 23 for judging the soot clogging of the heat exchanger 4 and taking action according to the level of the soot clogging state will be described sequentially according to the flowchart shown in FIG. .

S1 (signal shown on left shoulder, the same applies hereinafter)
Then, the operation switch 25 is turned on to turn on the power to the controller 18 from the external power supply, and prepare for the operation start. When the hot water tap 15 is opened in S2, the water amount detector 2 detects the flow of water to the water supply channel 1, and the controller 18 receiving this detection signal determines the operation start. Then, in S3, the combustion amount indicator 2
0 calculates the hot water supply load based on the detection signals from the water amount detector 2 and the incoming water temperature detector 3 and the setting signal of the hot water temperature setting device 27 input when the hot water tap 15 is opened. When the hot water supply load exceeds the maximum capacity of the water heater, an instruction is given to the drive circuit 19 to throttle the hot water supply flow rate to the maximum capacity. When the hot water supply load is calculated, the respective supply amounts from the proportional valve 11 and the blower fan 16 are obtained, and an instruction signal is output. The drive circuit 19 receiving this signal outputs a drive current to the proportional valve 11 and the blower fan 16. In S4, the burner 5 burns and the feed water passing through the heat exchanger 4 is heated and heated by the combustion air supplied by the blower fan 16 and the gas supplied by the proportional valve 11, and the hot water tap 15
Supplies hot water at the set temperature.

When the combustion of the burner 5 is continued after the predetermined time has elapsed and stabilized, the current detection circuit 21 detects the fan drive current I which the drive circuit 19 outputs to the blower fan 16 in S5. On the other hand, the efficiency determination circuit 22 calculates the heat output of the heat exchanger 4 based on the detection signals from the water amount detector 2, the incoming water temperature detector 3, and the hot water temperature detector 13, and further calculates the heat output and the combustion amount. The heat efficiency η of the heat exchanger 4 is calculated from the heat input corresponding to the hot water supply load calculated by the indicator 20.
The calculated thermal efficiency η and the fan drive current I are determined as follows by the efficiency determination circuit 22 and the fan current determination circuit 23 in each flow from S6 to S7.

In S6, it is determined whether or not the point a shown in FIG. 4 has been reached, and the efficiency ηa and the current Ia corresponding to the value A on the vertical axis are determined.
Are compared with the current I as the detection value and the efficiency η. When the current I and the efficiency η exceed the current Ia and the efficiency ηa, respectively, a point b at the next level is obtained in S7.
Is determined. When the point b has not been reached, there is no problem in use yet, but the warning level at the point a is displayed on the display 26, and it is notified in advance that the use state will soon deteriorate, and as shown in S9. Driving continues. When the point b is exceeded in S7, the combustion state deteriorates at an accelerated rate thereafter, and the dangerous state at the point c is reached soon. Therefore, the efficiency determination circuit 22 and the fan current determination circuit 23 immediately stop the operation as shown in S10, perform a measure to prohibit the subsequent operation, and display the fact on the display 26.

The above determinations in S6 and S7 combine the determinations of the two determination circuits 22 and 23, thereby improving the reliability of the determination. However, when one of the determination circuits cannot perform the correct determination operation, the determination result of the other determination circuit alone is adopted, not necessarily based on the composite determination. That is, the two determination circuits 22, 2
3 also has use states that cannot be determined. For example, in the case of the fan current determination circuit 23, when a strong wind exceeding the outdoor setting reference is applied to the exhaust chamber 9, the blower fan 16 receives a strong resistance. Then, the state cannot be distinguished from the resistance due to soot clogging. However, even if the combustion state becomes poor, the efficiency determination circuit 22 detects a better state than the fan current determination circuit 23. That is, the two determination circuits 22 and 23
If the judgment results do not match, take action based on the good judgment result. When the flow rate of hot water supply is small and the load of hot water supply is small, the thermal efficiency is lower than at other hot water supply loads. However, the fan current determination circuit 23 makes a determination based on the ratio data for soot clogging of the drive current proportional to the hot water supply load, has a determination ability regardless of the degree of the hot water supply load, and can make a correct determination independently. .

FIG. 6 shows another embodiment of the present invention.
The controller 28 is different from the above embodiment. The controller 28 does not change the drive circuit 19 and the combustion amount indicator 20, and the voltage detection circuit 29 detects the drive voltage output from the drive circuit 19 to the blower fan 16. Further, a rotation speed determination circuit 3 as a soot rotation speed determination device for determining the degree of clogging of the heat exchanger.
0 is provided. When the heat exchanger 4 advances in the soot clogging state in the same manner as in the above embodiment, the voltage detection circuit 29 detects the drive voltage output to the blower fan 16 by the drive circuit 19 and outputs the drive voltage to the rotation speed determination circuit 30. I do. When the heat exchanger 4 is clogged with soot, the fan drive current changes its current value with respect to the same supply voltage due to a decrease in the number of revolutions based on a decrease in the work amount of the blower fan 16. For this reason, the blower fan 1
6, a drive voltage is detected instead of the drive current as the drive signal to the drive signal 6. This detected drive voltage corresponds to the degree of soot clogging of the heat exchanger 4 and can be compared with a plurality of comparison criteria for warning and operation prohibition, and the degree of soot clogging can be determined according to the progress level.

As described above, according to the present embodiment, a troublesome control sequence for controlling the blower fan 16 to a predetermined number of rotations becomes unnecessary, so that the determination operation can be simplified and, for example, the heat exchanger 4 after the combustion is stopped is burned. Soot clogging can be determined by a very easy and simple circuit configuration during the post-purge, in which the accumulated heat is stored and the accumulated water is boiled, and the cooling fan is blown by the blower fan 16 to prevent so-called after-boiling.

The present invention is not limited to the above-mentioned water heater, but includes a heater of a hot water heating device for circulating hot water to an indoor radiator, a bath reheating heater for circulating and heating bath water, and a circulating heater for indoor air. It can also be widely used for combustion equipment such as a warm air heater for heating a living room, and can improve a use condition in which the heat exchanger reaches a dangerous state at the end of use.

[0031]

As described above, according to the first aspect of the present invention, there is provided a safety device for clogging soot of a burning appliance, in which the heat exchanger deposits soot on the passage of the combustion gas from the burner by unburned carbon or the like. However, when the exhaust gas is blocked, the soot clogging efficiency determiner compares the heat efficiency of the heat exchanger calculated based on the detection signals of the respective detectors with a predetermined heat efficiency, so that the soot clogging is accurately performed.
Level, for example, when the incoming water temperature is low and the
Normal for soot clogging when temperature does not reach constant temperature
You can use hot water for the time being at low temperature
But the inlet temperature is too high and the outlet temperature does not reach the set temperature
In this case, it is natural that the thermal efficiency is
Judgment of soot clogging, which impairs usability
The degree of soot clogging can be accurately determined without any problem. Yo
As a result, it is possible to detect the condition before the heat exchanger cracks or breaks at the end of the process and reaches dangerous operation. It is possible to use the burning appliance in a safe state and with security.

[0032]

[0033]

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a soot clogging safety device for a combustion appliance of the present invention.

FIG. 2 is a partially enlarged sectional view of a heat exchanger of the apparatus.

FIG. 3 is a partially enlarged sectional view of a heat exchanger of the apparatus.

FIG. 4 is a characteristic diagram that changes due to soot clogging of a combustion appliance.

FIG. 5 is a flowchart showing the operation.

FIG. 6 is a configuration diagram of a controller showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 16 blower fan 17 rotation number detector 19 drive circuit 20 combustion amount indicator 21 current detection circuit 22 efficiency determination circuit 23 fan current determination circuit 29 voltage detection circuit 30 rotation number determination circuit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Kotani 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-200133 (JP, A) JP-A-2-2 146412 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23N 5/24 104 F23N 5/14 370

Claims (1)

(57) [Claims] 1. An incoming water temperature detector for detecting an incoming water temperature to a heat exchanger, a water amount detector for detecting a passing water flow rate, a burner for heating the incoming water, and a fuel control means for adjusting a fuel supply amount to the burner. A hot water temperature detector for detecting a hot water temperature from the heat exchanger and a hot water temperature setting device for setting, receiving signals from the detectors and the hot water temperature setting device, and calculating a heating load of the heat exchanger. Calculate the thermal efficiency of the burner indicator and the heat exchanger that output a command signal for adjusting the fuel supply to the fuel control means and compare it with a predetermined thermal efficiency to determine the degree to which the heat exchanger has clogged the combustion gas passage from the burner. and determining soot clogging efficiency determination unit
Soot clogging safety device combustion instrument with a.