JPH05332531A - Burner with heat exchanger - Google Patents

Abstract

PURPOSE:To suppress vibrating combustion at the time of starting and to prevent noise, vibration of a burner with a heat exchanger by providing a dumper in a vent passage, and setting an opening of the dumper to a small value at the time of starting. CONSTITUTION:Premixed gas of air and fuel generated at the time of supplying hot water is fed to a vent passage 3a. A pair of right and left dumpers 10 to be so operated as to increase pressure loss of both the passage 3a and a burner port 4 at the time of starting are provided in the passage 3a. The pressure loss of an upstream side from the port 4 at the time of starting is increased by regulating the opening of the dumper 10. As a result, vibrating combustion at the time of starting can be prevented. A temperature detector 12a is provided in the passage 3a and a dumper controller 11 is provided out of combustion gas, and the opening of the dumper 10 may be increased slightly until it reaches a predetermined temperature. Thus, the opening of dumper the can be continuously controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor with a heat exchanger used for heating, hot water supply and the like.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram of a conventional hot water supply combustor.

At the time of hot water supply, the air in the mixing chamber 51 and the fuel sent from the fuel supply section 59 are mixed in the mixing chamber 51 to generate a premixed gas. The generated premixed air is sent to the air passage a53 while being further mixed by the blower 52, and further reaches the flame port 54 provided downstream of the air passage a53. At the start of hot water supply, the premixed mixture is ignited by the igniter 55. The premixed gas burns in the flame opening 54 to become high-temperature combustion gas, and the air passage b5 provided downstream of the flame opening 54
The high temperature gas is discharged toward 6. The discharged combustion gas is sent to the heat exchanger 57 provided downstream of the ventilation path b56, and exchanges heat with the fluid passing through the inside of the heat exchanger 57. The combustion gas that has been heat-exchanged and cooled is discharged into the atmosphere through a ventilation path c58 provided downstream of the heat exchanger 57.

This apparatus takes a combustion mode called total primary combustion in which air and fuel necessary for combustion are mixed and burned in advance, and sometimes vibrating combustion is performed. In particular, vibration combustion often occurs at startup.

[0005]

In the above conventional structure, vibration combustion is likely to occur particularly at the time of start-up, and noise or vibration is generated from the combustor with a heat exchanger, which exceeds the environmental standard of noise, and sometimes heat is generated by vibration. There was a problem that the combustor with the exchanger was damaged.

[0006]

The technical means used in the present invention to solve the above-mentioned conventional problems are as follows.

According to a first aspect of the present invention, as described in claim 1, a damper is provided in the air passage a, and a damper controller for setting the damper opening to a small value at the time of starting is provided.

In the first aspect of the present invention, it is preferable that a temperature detector is provided in the air passage a and the damper controller is configured to control the opening degree of the damper based on the temperature detected by the temperature detector. Further, in the first aspect of the invention, pressure detectors are provided at appropriate positions of the ventilation path b and at appropriate positions between the damper and the blower, and the damper is activated by the pressure difference between the pressures detected by the pressure detectors. Suitably, the damper controller is configured to control.

According to a second aspect of the present invention, as described in claim 4, an exhaust fan is provided in the air passage c, and an exhaust fan controller for controlling the operation of the exhaust fan so as to rotate at high speed at startup is provided. It is a thing.

In the second aspect of the invention, it is preferable that a pressure detector is provided at the inlet side or the outlet side of the exhaust fan, and the exhaust fan controller is configured to control the rotation of the exhaust fan based on the pressure detected by the pressure detector. Is. The second
In the present invention, it is preferable that a temperature detector is provided on the inlet side or the outlet side of the exhaust fan, and the exhaust fan controller is configured to control the rotation of the exhaust fan based on the temperature detected by the temperature detector.

[0011]

The present invention has the following actions by the above means.

According to the first aspect of the invention, since the damper arranged in the air passage a is controlled by the damper controller and the damper opening degree is set to a small value at the time of starting, the pressure loss on the upstream side of the flame mouth portion becomes large. , It is possible to prevent oscillatory combustion that occurs at startup.

According to the second aspect of the invention, the exhaust fan arranged in the ventilation passage c is controlled by the exhaust fan controller and rotates at a high speed during vibration, so that the exhaust draft of the ventilation passage b and the ventilation passage c increases and the exhaust gas is exhausted. Therefore, it is possible to prevent the oscillating combustion that occurs at the time of startup.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

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

At the time of hot water supply, the air in the mixing chamber 1 and the fuel sent from the fuel supply unit 9 are mixed in the mixing chamber 1 to generate a premixed gas. The generated premixed air is sent to the ventilation passage a3 while being further mixed by the blower 2, and further reaches the flame port 4 provided downstream of the ventilation passage a3. At the start of hot water supply, the premixed mixture is ignited by the igniter 5. Flame part 4
In the above, the premixed gas burns into a high-temperature combustion gas, and the high-temperature combustion gas is discharged toward the ventilation path b6 provided downstream of the flame mouth portion 4. The exhausted combustion gas is sent to the heat exchanger 7 provided downstream of the ventilation path b6, and exchanges heat with the fluid passing through the inside of the heat exchanger 7. The combustion gas cooled by heat exchange is
It is discharged into the atmosphere through a ventilation path c8 provided downstream of the heat exchanger 7.

It is known that in order to prevent oscillatory combustion, the pressure loss on the downstream side of the flame opening 4 should be small and the pressure loss on the upstream side of the flame opening 4 should be large.

In the above structure, during steady combustion, the air passage a3 upstream of the flame port 4 reaches several tens to one hundred and several tens of degrees Celsius. However, at the time of start-up, the air passage a3 on the upstream side of the flame port 4 is at room temperature, and the temperature is lower and the viscous resistance is smaller than that during steady combustion, so the pressure loss is small. Therefore, vibration combustion is easily performed. To prevent this, the following is effective.

In the first embodiment, a pair of left and right dampers 10 are provided inside the air passage a3 so that the combined pressure loss of the air passage a3 and the flame port 4 is large at the time of starting. .. By adjusting the opening degree of the damper 10, the pressure loss at the time of starting upstream of the flame port 4 is increased. As a result, it is possible to prevent oscillatory combustion that occurs at startup. The damper 10 is controlled such that the time for heating the ventilation path a3 is obtained in advance, and the opening of the damper 10 is reduced only at the time of startup (when the temperature is low) so that vibration combustion does not occur. For this purpose, a separate damper controller 11 for controlling the damper 10 may be used, or a shape memory alloy or the like may be used for the damper 10 so that the damper 10 itself has a control function.

The second embodiment is the same as the first embodiment except that
A temperature detector a12 and a damper controller 11 are provided outside the combustor in the air passage a3, and the opening of the damper 10 is gradually increased until a predetermined temperature is reached. As a result, the opening degree of the damper 10 can be continuously controlled.
That is, the control as in the first embodiment makes it possible to detect the fluctuation of the pressure in the air passage a3 more accurately, so that the fluctuation becomes smoother and the time until the steady operation is shortened.

In the first embodiment, the damper 1
The pressure detector a13 and the pressure detector b14 are provided at appropriate positions between 0 and the blower 2 and at appropriate positions of the ventilation path b6.
The third embodiment can be configured by providing the damper controller 11 outside the combustor. As a result, the opening degree of the damper 10 is controlled to be gradually increased until the differential pressure value detected by the two pressure detectors a13 and b14 reaches or exceeds a predetermined value. As a result, it is possible to prevent oscillating combustion that occurs at the time of hot water supply startup, and to shorten the time required for steady operation.

The combustor shown in FIG. 1 is set in a vertical direction and is exhausted upward. A preferred embodiment applied to such a type of combustor will be described below.
During steady combustion, the temperature of the combustion gas is 10 in the air passage b6.
The temperature may reach more than 00 ° C, and the vent passage c8 may reach several hundreds of ° C. Therefore, during steady combustion, the smoke-draft effect due to natural convection is larger than the increase in viscous resistance due to the temperature rise inside the ventilation passages b6 and c8. Get smaller. On the other hand, immediately after the start-up, since the air passage b6 and the air passage c8 downstream of the flame port 4 are at room temperature, there is almost no smoke-draft effect, the pressure loss becomes large, and vibration combustion easily occurs. To prevent this, the following is effective.

In the fourth embodiment, an exhaust fan 15 is provided inside the air passage c8 so as to facilitate the exhaust at the time of startup and increase the exhaust draft of the air passage b6 and the air passage c8. As a result, it is possible to prevent oscillating combustion that occurs when hot water supply is started. The control of the exhaust fan 15 and the time for heating the ventilation passage c8 are obtained in advance, and during that time, the rotation operation of the exhaust fan 15 is made faster than during steady combustion to prevent oscillatory combustion. To this end, an exhaust fan controller 18 that controls the exhaust fan 15
Is used.

The fifth embodiment is different from the fourth embodiment in that a pressure detector c16 is provided at the inlet side of the exhaust fan 15,
Alternatively, the pressure detector d17 is provided on the outlet side of the exhaust fan 15, and the exhaust fan controller 18 is provided outside the combustor. Thus, the pressure on the inlet side or the outlet side of the exhaust fan 15 is detected, and the rotation of the exhaust fan 15 is controlled to decrease from high speed to low speed when the pressure becomes equal to or lower than a predetermined value. As a result, it is possible to prevent oscillating combustion that occurs at the time of hot water supply startup, and to shorten the time required for steady operation. The exhaust fan 15
It is possible to gradually reduce the rotation speed of the motor as the pressure decreases.

In the sixth embodiment, in the second invention, a temperature detector b19 is provided on the inlet side of the exhaust fan 15 or a temperature detector c20 is provided on the outlet side and the exhaust fan controller 18 is provided outside the combustor. It is provided. This detects the temperature at the inlet or outlet of the exhaust fan,
The exhaust fan 15 is controlled so as to be high speed at low temperature and low speed at high temperature. As a result, it is possible to prevent oscillating combustion that occurs at the time of hot water supply startup, and to shorten the time required for steady operation.

Although the hot water supply combustor is shown in the above embodiment,
The same effect can be observed when the present invention is applied to a heat exchanger for warm air and other heat exchangers for heating.

[0027]

The present invention has the following effects.

The effect of the first invention is that by increasing the pressure loss on the upstream side of the flame opening at the time of startup, it is possible to prevent oscillatory combustion that occurs at startup.

In the first invention, the damper is controlled by the temperature detected by the temperature detector,
Oscillatory combustion that occurs at startup can be prevented smoothly, and the time required for steady operation can be shortened. Also,
In the first aspect of the invention, the damper is controlled by the pressure difference between the pressures detected by the two pressure detectors, so that the oscillating combustion that occurs at the time of startup can be smoothly prevented, and the time until the steady operation is reached. Can be shortened.

The effect of the second invention is that by increasing the exhaust draft on the upstream side of the flame mouth portion at the time of starting, it is possible to prevent the oscillating combustion occurring at the time of starting.

In the second aspect of the present invention, the pressure on the inlet side or the outlet side of the exhaust fan is detected and the exhaust fan is controlled, so that oscillating combustion that occurs at startup can be smoothly prevented and steady operation is achieved. The time to reach can be shortened. Further, in the second aspect of the present invention, the temperature at the inlet side or the outlet side of the exhaust fan is detected and the exhaust fan is controlled, whereby oscillating combustion that occurs at startup can be smoothly prevented, and steady operation is achieved. You can shorten the time until.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a hot water supply combustor according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a hot water supply combustor of a conventional example.

[Explanation of symbols]

 1 Mixing Chamber 2 Blower 3 Ventilation Path a 4 Flame Port 6 Ventilation Path b 7 Heat Exchanger 8 Ventilation Path c 10 Damper 11 Damper Controller 12 Temperature Detector a 13 Pressure Detector a 14 Pressure Detector b 15 Exhaust Fan 16 pressure detector c 17 pressure detector d 18 exhaust fan controller 19 temperature detector b 20 temperature detector c

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F24H 1/10 303 Z

Claims (6)

[Claims] 1. A blower, a fuel supply unit, a mixing chamber for mixing air sent by the blower and fuel sent from the fuel supply unit, and ventilation of a premixed gas generated in the mixing chamber. A passage a, a flame opening provided downstream of the ventilation passage a, a ventilation passage b provided downstream of the flame opening, a heat exchanger provided in the ventilation passage b, and a heat exchanger provided downstream of the heat exchanger. A combustor with a heat exchanger provided with a ventilation passage c, wherein a damper is provided in the ventilation passage a and a damper controller for setting a small opening degree of the damper at startup is provided. Combustor. 2. The combustor with a heat exchanger according to claim 1, wherein a temperature detector is provided in the air passage a, and the damper controller is configured to control the opening of the damper based on the temperature detected by the temperature detector. 3. A pressure detector is provided at each of the proper position of the ventilation path b and the proper position between the damper and the blower, and the operation of the damper is controlled by the pressure difference between the pressures detected by both pressure detectors. The combustor with a heat exchanger according to claim 1, wherein the damper controller is configured as described above. 4. A blower, a fuel supply section, a mixing chamber for mixing the air sent by the blower and the fuel sent from the fuel supply section, and the ventilation of the premixed gas generated in the mixing chamber. A passage a, a flame opening provided downstream of the ventilation passage a, a ventilation passage b provided downstream of the flame opening, a heat exchanger provided downstream of the ventilation passage b, and a heat exchanger provided downstream of the heat exchanger. Air passage c
In a combustor with a heat exchanger, the heat exchanger is provided with an exhaust fan in the air passage c and an exhaust fan controller for controlling the operation of the exhaust fan so as to rotate at high speed at startup. Combustor with. 5. The heat exchanger according to claim 4, wherein a pressure detector is provided on an inlet side or an outlet side of the exhaust fan, and the exhaust fan is configured to control rotation of the exhaust fan based on pressure detected by the pressure detector. Combustor with. 6. The heat according to claim 4, wherein a temperature detector is provided on the inlet side or the outlet side of the exhaust fan, and the exhaust fan controller is configured to control the rotation of the exhaust fan based on the temperature detected by the temperature detector. Combustor with exchanger.