JP2000074367A - Combustor and hot-water supplier provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of an offensive odor while the ignitability of a combustor at the time of igniting the combustor is secured in a superior state by setting the mixing ratio of a mixed fuel supplied to a combusting section when the combustor is ignited on the fuel-rich side on the basis of the optimum mixing ratio at which the fuel makes complete combustion when the combustion is continued. SOLUTION: In initial combustion treatment, an igniter 31 is ignited by supplying fuel by the amount corresponding to an output number (for example, number 7.8) larger than the lower-limit output number (number 4.8) to a carburetor 20 by driving a constant-flow pump 43 while the number of revolutions of a supply fan 51 is maintained at the value (for example, 2,200 rpm) corresponding to the lower-limit output number (number 4.8) of allowable output numbers (for example, numbers 4.8-26). In short, the mixing ratio of mixed fuel supplied to a combusting section when an igniter 31 is ignited is set on the fuel-rich side, namely, the amount of the air supplied by means of the supply fan 51 is set to number 4.8 or equivalent and the amount of the fuel supplied by means of the constant-flow pump 43 is set at number 7.8 or equivalent in order the suppress the occurrence of an offensive odor while the stable ignitability of the igniter 31 is secured at the time of igniting the igniter 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device for supplying air to a combustion section to perform a combustion operation and a hot water supply device provided with the combustion device.

[0002]

2. Description of the Related Art As a conventional combustion apparatus, for example, there is a liquid fuel vaporization type combustion apparatus. In this type of combustion apparatus, a vaporized fuel obtained by vaporizing fuel such as kerosene and air are mixed in a combustion section. And ignited and burned in the combustion section.

Conventionally, at the time of ignition, instead of immediately supplying a mixed fuel corresponding to a required combustion capacity, in order to achieve ignition stability, a mixed fuel corresponding to a lower limit combustion capacity set in an apparatus is supplied. After ignition, control is performed so as to gradually increase the amount of fuel to the mixed fuel corresponding to the required combustion capacity.

[0004] The mixing ratio of the above-mentioned mixed fuel is set to an optimum value for complete combustion in a stable combustion state such as during continuous combustion. This optimum value is determined experimentally. Incidentally, when the mixture ratio of the mixed fuel is on the fuel lean side (small fuel supply amount side), an odor tends to be easily generated, and when the mixture ratio is on the fuel rich side (high fuel supply amount side), soot is easily generated. It becomes a tendency.

[0005]

In the above-described conventional combustion apparatus, for example, in a situation where ignition is repeated frequently,
It was found that off-flavors were likely to occur. For example, in the case of a hot water supply device equipped with the above-described combustion device, there are many situations where the hot water supply is repeatedly performed in a short time,
In such a case, an unpleasant odor is generated from the combustion part.
The generation of such an unpleasant odor may cause the user to feel distrust.

[0006] In the first place, the combustion state becomes unstable immediately after ignition, for example, the flame tends to fluctuate, so that incomplete combustion tends to occur. Nevertheless, in the past, even at the time of ignition, the mixture ratio of the mixed fuel was set to be the same as the optimal mixture ratio for complete combustion in a stable combustion state, such as during continuous combustion, so that the above-mentioned odor generation occurred. It can be said that the malfunction occurred. From this, it can be said that the mixing ratio of the mixed fuel supplied to the combustion section at the time of ignition is not optimal,
There is room for improvement here.

[0007] In view of such circumstances, an object of the present invention is to provide a combustion device and a hot water supply device capable of suppressing generation of an unusual odor while securing good ignitability at the time of ignition.

[0008]

According to a first aspect of the present invention, there is provided a combustion apparatus for burning a mixed fuel obtained by mixing air and vaporized fuel. The fuel-rich side is set on the basis of the optimum mixing ratio at which the combustion is almost complete when the combustion is continued.

A combustion unit according to a second aspect of the present invention includes a combustion unit for burning a mixed fuel obtained by mixing air and vaporized fuel;
An air supply unit that supplies air to the combustion unit, a fuel supply unit that supplies vaporized fuel to the combustion unit, and a management unit that controls a combustion operation in the combustion unit, wherein the management unit includes:
The mixture ratio of the mixed fuel supplied to the combustion part at the time of ignition is
The fuel-rich side is set on the basis of the optimum mixing ratio at which the combustion is almost complete when the combustion is continued.

A combustion unit according to a third aspect of the present invention comprises a combustion unit for burning a mixed fuel obtained by mixing air and vaporized fuel;
An air supply unit that supplies air to the combustion unit, a fuel supply unit that supplies vaporized fuel to the combustion unit, and a management unit that controls a combustion operation in the combustion unit, wherein the management unit includes:
When a combustion request is received, first, an initial combustion process with a combustion capability smaller than the required combustion capability is performed, and a combustion control for gradually starting up to the required combustion capability is performed. In the above, the mixing ratio of the mixed fuel supplied to the combustion section is set on the fuel rich side on the basis of the optimum mixing ratio at which the combustion is substantially complete when the combustion is continued.

According to a fourth aspect of the present invention, there is provided a combustion device for burning a mixed fuel obtained by mixing air and vaporized fuel;
An air supply unit that supplies air to the combustion unit, a fuel supply unit that supplies vaporized fuel to the combustion unit, and a management unit that controls a combustion operation in the combustion unit, wherein the management unit includes:
When a combustion request is received, first, an initial combustion process with a combustion capability smaller than the required combustion capability is performed, and a combustion control for gradually starting up to the required combustion capability is performed. In addition to setting the mixture ratio of the mixed fuel supplied to the combustion unit to a fuel rich side with reference to the mixture ratio at which combustion is substantially complete when combustion continues, the mixture ratio of the mixed fuel supplied to the combustion unit after ignition is determined The correction is made so as to match the optimum mixing ratio at which the combustion is almost complete during the continuation.

According to a fifth aspect of the present invention, there is provided a hot water supply apparatus, wherein water is passed from one end side to the other end side, and a middle portion is provided to a combustion section of the combustion apparatus. A heat exchange pipeline penetrated therethrough.

In summary, according to the present invention, the mixture ratio of the fuel mixture supplied to the combustion section is not the same between the time of ignition and the time of continuous combustion, but the mixture ratio at the time of ignition is set to the optimum mixture ratio during continuous combustion. On the other hand, it is set on the fuel rich side. This ensures good ignitability during ignition,
It is possible to suppress the generation of off-flavors.

According to the fourth aspect of the present invention, since the mixture ratio is corrected to an optimum mixture ratio at which the combustion is substantially complete when the combustion is continued after ignition, the process is shifted from the initial combustion process to the combustion control process with the required combustion capacity. This makes it possible to avoid abnormal combustion during the transition period.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on embodiments shown in the drawings.

FIGS. 1 to 3 relate to an embodiment of the present invention. FIG. 1 is a view showing an entire hot water supply apparatus, and FIG.
FIG. 3 is a diagram showing a combustion device in the inside, and FIG. 3 is a diagram showing a control flow used for explaining the operation.

In the figure, A indicates the entire combustion apparatus. The combustion apparatus A includes a heat exchange can 10, a carburetor 20, a burner 30 corresponding to a combustion section, a fuel supply means 40, and an air supply. A blower 50 corresponding to the means and a damper 60 are provided. For this combustion apparatus A, a hot water supply circuit 70, a bath re-cooking circuit 80, and a controller 9 corresponding to management means are provided.
0 is attached to the water supply device.

A vaporizer 20 and a burner 30 are arranged below the heat exchange can 10, and heat exchange circuits of a hot water supply circuit 70 and a bath reheating circuit 80 are arranged above the heat exchange can 10. Pipes 72 and 82 are penetrated.

The vaporizer 20 vaporizes liquid fuel such as kerosene supplied from the fuel supply means 40, and includes a diffusion blade 21, a vaporization heater 22, a vaporizer temperature sensor 23, a vaporization wall surface 24, a mixing chamber 25, Mixing chamber heater 26, motor 2
7, an air supply temperature sensor 28, a motor speed sensor 29, and the like. In the vaporizer 20, the supplied liquid fuel is scattered on the vaporizing wall 24 around the diffusion blade 21 by rotating the diffusion blade 21 by the motor 27,
Vaporization is performed by heat from the vaporization heater 22 and the mixing chamber heater 26. In addition, the supply air temperature sensor 2
Numeral 8 detects the temperature of the air sent to the vaporizer 20 and the burner 30.

The burner 30 ignites and burns the vaporized fuel supplied from the vaporizer 20 and the air supplied from the blower 50, and comprises an igniter 31 and a flame detector 32.

The fuel supply means 40 supplies liquid fuel from a liquid fuel tank (not shown) to the vaporizer 20, and includes a pump 41, a sub-tank 42, a constant flow pump 43 and the like. Since the detailed structure of the constant flow pump 43 is well known, it is not shown.

The blower 50 includes the vaporizer 20 and the burner 3.
0 to supply air to the air blower 5
1, a drive motor 52, a rotation speed sensor 53, and the like.

The damper 60 is provided in the middle of a ventilation passage connecting the carburetor 20 and the blower 50, and controls the opening of the ventilation passage to control the amount of ventilation to the burner 30 as the combustion part. Is what you do. This damper 60 is located at a position where the ventilation passage is closed by driving means such as a motor (not shown) (see FIG. 2).
(See the solid line) and the position to open the ventilation path (see the broken line in FIG. 2)
Is displaced into two states: The damper 60 here is
At the closed position, the required ventilation is possible without completely closing the ventilation path, and at the open position, the ventilation path is opened to allow the maximum ventilation. A limit switch 62 is provided on the closed position side of the damper 60 to detect the open / close position of the damper 60. When the damper 60 is at the closed position, the contact is closed and the limit switch 62 is turned on, and when the damper 60 is at the open position, the contact is opened and turned off.

In the combustion apparatus A having such components 10 to 60, liquid fuel such as kerosene supplied from the fuel supply means 40 is vaporized by the vaporizer 20 and the vaporized fuel is supplied to the air supplied from the blower 50. And the mixture at a required ratio and sent to the burner 30 for combustion.

The water passing through the heat exchange pipes 72 and 82 of the hot water supply circuit 70 and the bath reheating circuit 80 in the heat exchange can 10 is heated by the combustion heat. The air supplied from the blower 50 and passed through the damper 60 is sent to the carburetor 20 side as primary air, and is also directly supplied to the burner 30 as secondary air, and a part of the secondary air is invalid air. And passes through the heat exchange can 10.

The hot water supply circuit 70 has a bypass mixing structure in which, for example, tap water or the like is mixed with hot water heated by the combustion device A and a part of the tap water, and the hot water is supplied from a hot water supply curran (see a broken line). The hot water supply circuit 70 includes a water inlet pipe 71,
Heat exchange line 72, tapping line 73, bypass line 74, hot water supply line 75, incoming water flow sensor 76, incoming water temperature sensor 7
7, a tap water temperature sensor 78, a hot water supply temperature sensor 79, and the like. The hot water supply pipe 75 is branched on the way into a general hot water supply pipe 75a and a hot water supply pipe 75b.

The bath after-cooking circuit 80 takes out bath water from a bathtub (not shown), heats the bath water to a required temperature by the combustion device A, and returns the bath water to the bathtub. The hot water supply circuit 70 can mix hot water at a required temperature. It has such a structure. The bath reheating circuit 80 includes a bath return line 81, a heat exchange line 8,
2. A bath line 83, a bypass line 84, a circulation pump 86 and the like are provided.

The controller 90 executes at least the hot water supply operation shown in FIG. In this hot water supply operation, when the water supply amount sensor 76 detects the minimum operation water amount MOQ or more, for example, by opening a hot water supply curl, data of the required hot water supply flow rate, the required hot water supply temperature, and the incoming water temperature input from the sensors. The required output number, that is, the required amount of combustion heat is calculated based on the above, and the combustion control corresponding to the required output number is performed. In this combustion control, the opening and closing of the damper 60 is performed by adding the combustion heat amount by the FB (feedback) control to the combustion heat amount by the FF (feed forward) control so that the actual combustion heat amount approaches the required combustion heat amount (required output number). The operation, the amount of air supplied by the blower 50 (the number of rotations by the blower fan 51), and the amount of fuel supplied by the constant flow pump 43 are controlled. In this embodiment, the calculated required output number, that is, the total combustion heat quantity (FF combustion number + FB combustion number) is converted into a first reference value and a second reference value (first reference value + required value) determined in advance. Then, whether the damper 60 is in the open position or the closed position is determined. The reason for using the two reference values in this way is that if the required output number does not exceed the second reference value even if the required output number exceeds the first reference value, the damper 60 is used.
Is held in the closed position, the hysteresis in switching the damper 60 is substantially increased, and the occurrence of a hunting phenomenon in which the damper 60 opens and closes frequently is prevented.

A feature of the present invention is that an initial combustion process is devised until a combustion control corresponding to a required output number is performed when starting hot water supply.

Next, the operation of the water heater will be described with reference to the control flow of FIG.

When an operation switch (not shown) is turned on in step n1, preheating is applied to the vaporizer 20 in steps n2 and n3. Here, the vaporizing heater 22 is driven until the value detected by the vaporizer temperature sensor 23 reaches a required set temperature. Thereafter, in step n4, the process waits for a combustion command to be input. As the combustion command, there are a hot water supply request and a post-cooking request.

Here, when a combustion command is input, a required combustion capacity, that is, a required output number is calculated and obtained in step n5, and then initial combustion processing relating to initial combustion such as ignition is performed in steps n6 to n12 described below. Then, in step n13, a combustion control process for gradually increasing the required combustion capacity is performed.

In the above-described initial combustion process, step n
6 and n7, the blower fan 51 is driven to maintain the rotation speed (for example, 2200 rpm) corresponding to the lower limit output number (4.8) of the allowable output number (for example, 4.8 to 26). In step n8, the constant flow pump 43 is driven to supply the fuel to the carburetor 20 in an amount corresponding to an output number (for example, 7.8) larger than the lower limit output number (4.8). In step n9, the igniter 31 is ignited. in short,
In the above steps n6 to n8, in order to suppress the generation of offensive odor while securing the ignition stability at the time of ignition, the mixing ratio of the mixed fuel supplied to the combustion unit at the time of ignition is set to the combustion rich side, that is,
The amount of air supplied by the blower fan 51 is set to 4.8, and the amount of fuel supplied by the constant flow pump 43 is set to 7.8. By the way, if both the air supply amount and the fuel supply amount are equivalent to the same output number, almost complete combustion can be performed during continuous combustion, and such a mixture ratio is called an optimum mixture ratio.

Thereafter, the process waits until the ignition is actually performed in step n10. The determination of the presence or absence of the ignition is performed by detecting the combustion flame by the flame detector 32. When the ignition is detected, the constant flow pump 43 is driven in step n11 so as to reduce the fuel supply amount from 7.8 to 4.8. Here, both the fuel supply amount and the air supply amount are set to 4.
By making it equivalent to No. 8, the optimum mixture ratio is corrected, thereby making it difficult to perform abnormal combustion in the transitional period when the process shifts to the combustion control process corresponding to the required combustion capacity in step n13 described below.

After this ignition, it waits for the time required for the flame ignited in step n12 to stabilize (for example, one second) to elapse, and after that elapses, in step n13, the required combustion capacity calculated in step n5 is reduced. Control to start up. This control is the same as the control that has been performed in the past, and a detailed description thereof will be omitted.

The allowable range when the mixture ratio of the mixed fuel supplied to the combustion section at the time of the initial combustion processing is set to the combustion rich side will be described.

That is, in order to set the mixture ratio on the fuel rich side, the fuel supply amount may be set to a value larger than that of No. 4.8, but if the fuel supply amount is set too large, soot is easily generated. Another problem such as a tendency occurs.

Therefore, the critical point of soot generation was examined by experiments. As a result, it was found that when the fuel supply amount was less than No. 8, soot was hardly generated. For this reason, the allowable range on the fuel rich side for preventing the generation of soot while suppressing the generation of unpleasant odor at the time of ignition is a range in which the fuel supply amount is larger than 4.8 equivalent and smaller than 8 equivalent. I found it. In the above embodiment, the reason why the fuel supply amount is set to 7.8 equivalent to the upper limit of the permissible range is to take into consideration the variation in the combustion capacity of the combustion apparatus A, and this 7.8 equivalent is used. Is just an example.

As described above, in the hot water supply apparatus of the present embodiment, when the combustion apparatus A is ignited, the mixture ratio of the mixed fuel supplied to the combustion section is not set to the optimum relation when the combustion is continued, and the fuel rich side is used. Since the initial combustion process is set to be set to, the generation of an odor can be suppressed while ensuring good ignitability at the time of ignition.

In addition, in the initial combustion process, the ignition ratio is corrected before returning to the combustion control process with the required combustion capacity so that the mixture ratio of the mixed fuel is returned to an optimum relationship when the combustion is continued. As a result, it is possible to avoid abnormal combustion in the transition period when the process shifts to the combustion control process with the required combustion capacity, as compared with the case where no correction is made.

In particular, in the above embodiment, the lower limit of the number of drive rotations of the blower fan 51 at the time of ignition is used.
Since the speed is set to 2200 rpm corresponding to No. 8, quietness can be ensured, and the advantage that the combustion flame can be prevented from extinguishing even in the event of a strong wind (eg, about 18 m / s) can be obtained. Thus, the hot water supply apparatus of the present embodiment can be used without any problem whether it is an indoor type or an outdoor type.

It should be noted that the present invention is not limited to only the above embodiment, and various applications and modifications are conceivable.

(1) In the above embodiment, the air supply amount in the initial combustion process is set to be equal to the lower limit output number.
The number setting may be changed according to the required output number. This means that if the required output number becomes large, such as the upper limit output number, for example, 26, the air supply amount in the initial combustion process may be set higher than the lower limit output number equivalent. . In this case, it is necessary to set the fuel supply amount on the fuel rich side with respect to the air supply amount described above.

[0044]

In the combustion apparatus according to the first to fourth aspects of the present invention, the mixture ratio of the mixed fuel supplied to the combustion portion at the time of ignition is not made equal to the optimum mixture ratio during the continuation of combustion, and the fuel-rich side is used. Because it is set to, it is possible to improve the flammability while securing the ignitability at the time of ignition, and it is possible to suppress the generation of offensive odor, especially when frequent ignition is repeated. And avoid distrust.

In particular, in the combustion apparatus according to the fourth aspect of the present invention, the mixture ratio is corrected to an optimum mixture ratio at which the combustion is substantially completed when the combustion is continued after ignition in the initial combustion process. It is possible to avoid abnormal combustion in the transition period when the process shifts to the combustion control process based on the capacity. By the way, since the flame is stable after ignition even in the initial combustion process, it is expected that if the fuel-rich mixture ratio at the time of ignition is left as it is without performing the correction, abnormal combustion in which soot is generated is likely to occur. According to the invention of claim 4, such a concern can be avoided.

Since the hot water supply apparatus according to the fifth aspect of the present invention has the above-described combustion apparatus, even if the hot water supply request is frequently repeated within a short time, for example, it is possible to prevent the generation of offensive odor and to stably produce the odor. It is not necessary to give the user distrust, for example, by supplying hot water.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a hot water supply device of the present invention.

FIG. 2 is a configuration diagram showing a combustion device in FIG. 1;

FIG. 3 is a diagram showing a control flow used for explaining the operation of the hot water supply device in FIG. 1;

[Explanation of symbols]

 A combustion apparatus 20 carburetor 30 burner 32 flame detector 40 fuel supply means 43 constant flow pump of fuel supply means 50 blower 90 controller

Continued on the front page (72) Inventor Hirokazu Kuwahara 93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Pref. (72) Inventor Hiroki Hasegawa 93-Edo-cho, Chuo-ku, Kobe-shi, Hyogo (72) ) Inventor Hitoshi Hara 93, Edocho, Chuo-ku, Kobe, Hyogo Prefecture Inside Noritz Co., Ltd. (72) Inventor Noriyuki Kanda 93, Edocho, Chuo-ku, Kobe City, Hyogo F-term in Noritsu Co., Ltd. (Reference) 3K003 AA01 AB02 AB06 AC01 AC03 BC06 CA03 CA05 CC01 DA04

Claims (5)

[Claims] 1. A combustion device for burning a mixed fuel obtained by mixing air and vaporized fuel, wherein a mixture ratio of the mixed fuel supplied to a combustion unit at the time of ignition is:
A combustion apparatus characterized in that it is set on the fuel rich side based on an optimum mixture ratio at which almost complete combustion is performed during continuous combustion. 2. A combustion section for burning a mixed fuel obtained by mixing air and vaporized fuel, air supply means for supplying air to the combustion section, fuel supply means for supplying vaporized fuel to the combustion section,
Management means for controlling the combustion operation in the combustion unit, the management means, the mixture ratio of the mixed fuel to be supplied to the combustion unit at the time of ignition, based on the optimal mixture ratio of almost complete combustion when the combustion is continued, A combustion device set on a fuel rich side. 3. A combustion section for burning a mixed fuel obtained by mixing air and vaporized fuel, air supply means for supplying air to the combustion section, fuel supply means for supplying vaporized fuel to the combustion section,
Management means for controlling a combustion operation in the combustion section, wherein the management means, when receiving a combustion request, first performs an initial combustion process with a combustion capacity smaller than the required combustion capacity, and gradually increases the required combustion capacity. The combustion control is performed so that the mixture ratio of the mixed fuel supplied to the combustion unit at the time of ignition in the initial combustion processing is determined based on the optimum mixture ratio at which the combustion is substantially completed when the combustion is continued. A combustion device, which is set on the side. 4. A combustion section for burning a mixed fuel obtained by mixing air and vaporized fuel, air supply means for supplying air to the combustion section, fuel supply means for supplying vaporized fuel to the combustion section,
Management means for controlling a combustion operation in the combustion section, wherein the management means, when receiving a combustion request, first performs an initial combustion process with a combustion capacity smaller than the required combustion capacity, and gradually increases the required combustion capacity. The combustion control is performed to increase the mixture ratio of the mixed fuel supplied to the combustion unit at the time of ignition in the initial combustion processing, based on the mixture ratio of substantially complete combustion when the combustion is continued, on the fuel rich side. Besides, after ignition, the mixing ratio of the mixed fuel supplied to the combustion section is
A combustion apparatus, wherein the correction is made so as to match an optimum mixture ratio at which combustion is almost complete when combustion is continued. 5. The combustion device according to claim 1, wherein:
A hot water supply device, comprising: a heat exchange pipe through which water is passed from one end side to the other end side and a middle portion penetrates through a combustion portion of the combustion device.