JP3073316B2 - Combustor with heat exchanger - Google Patents

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 and hot water supply.

[0002]

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

[0003] 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 air. The generated premixed gas is sent to the ventilation path a53 while being further mixed by the blower 52, and further reaches the flame port 54 provided downstream of the ventilation path a53. At the start of hot water supply, the premixed gas is ignited by the igniter 55. The pre-mixed gas burns in the flame port 54 to become a high-temperature combustion gas, and a ventilation path b5 provided downstream of the flame port 54 is provided.
Exhaust the hot gas towards 6. The discharged combustion gas is sent to a heat exchanger 57 provided downstream of the ventilation path b56, where it exchanges heat with a fluid passing through the inside of the heat exchanger 57. The combustion gas cooled by the heat exchange is discharged into the atmosphere through an air passage c58 provided downstream of the heat exchanger 57.

[0004] The present apparatus takes a combustion form of all-primary combustion in which air and fuel necessary for combustion are mixed in advance and burns, and may perform oscillating combustion. Especially at the time of startup, the combustion often occurs.

[0005]

In the above-mentioned conventional construction, vibration and combustion are liable to occur, especially at the time of startup, and noise and vibration are generated from the combustor with the heat exchanger. There was a problem that the combustor with 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, a damper is provided in a ventilation path a disposed downstream of the blower and upstream of the flame port, and the opening degree of the damper is reduced at the time of startup. A damper controller to be set is provided.

In the first aspect of the present invention, it is preferable that a temperature detector be provided in the ventilation path a and the damper controller be configured to control the degree of opening of the damper based on the temperature detected by the temperature detector. Further, in the first invention, a pressure detector is provided in each of an appropriate location of the ventilation path b and an appropriate location between the damper and the blower, and the operation of the damper is performed by a differential pressure between the pressures detected by the two pressure detectors. Preferably, the damper controller is configured to control.

According to a second aspect of the present invention, an exhaust fan is provided in the ventilation path c, and an exhaust fan controller that controls the operation of the exhaust fan so that the exhaust fan rotates at a high speed at startup is provided. Things.

[0010] In the second aspect of the present invention, it is preferable that a pressure 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 pressure detected by the pressure detector. It is. Also the second
In the present invention, it is preferable that a temperature detector be provided on the inlet side or the outlet side of the exhaust fan, and the exhaust fan controller be 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 effects by the above means.

According to the first aspect of the invention, the damper disposed in the ventilation path a downstream of the blower and upstream of the flame opening is controlled by the damper controller, and the opening degree of the damper is set small at the time of startup. Therefore, the pressure loss on the upstream side of the flame opening becomes large, and the oscillating combustion that occurs at the time of startup can be prevented. Even if the vibration combustion occurs, the influence of the vibration combustion can be attenuated at the damper portion, so that the influence on the blower and the fuel supply unit can be reduced.

According to the second aspect of the present invention, the exhaust fan disposed in the air passage c is controlled by the exhaust fan controller and rotates at a high speed during vibration, so that the exhaust draft of the air passage b and the air passage c increases, and the exhaust air is exhausted. Therefore, vibration combustion occurring at the time of startup can be prevented.

[0014]

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 according to one 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 air. The generated premixed gas is sent to the ventilation passage a3 while being further mixed by the blower 2, and further reaches the flame outlet 4 provided downstream of the ventilation passage a3. At the start of hot water supply, the premixed gas is ignited by the igniter 5. Flame mouth 4
In, the premixed gas burns to become a high-temperature combustion gas, and the high-temperature combustion gas is discharged toward the ventilation path b6 provided downstream of the flame opening 4. The discharged combustion gas is sent to a heat exchanger 7 provided downstream of the ventilation path b6, where it exchanges heat with a fluid passing through the inside of the heat exchanger 7. The combustion gas cooled by heat exchange is
The air 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 oscillating combustion, the pressure loss on the downstream side of the flame port 4 should be small and the pressure loss on the upstream side of the flame port 4 should be large.

In the above configuration, 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 startup, the air passage a3 on the upstream side of the flame port 4 is at room temperature, and has a lower temperature and lower viscous resistance than during steady combustion, so that pressure loss is small. As a result, the fuel easily vibrates. To prevent this, the following is effective.

In the first embodiment, a pair of right and left dampers 10 are provided inside the ventilation path a3 so as to operate so that the pressure loss of the combination of the ventilation path a3 and the flame opening 4 becomes large at the time of startup. . By adjusting the degree of opening of the damper 10, the pressure loss at the time of startup on the upstream side of the flame opening 4 is increased. As a result, it is possible to prevent oscillating combustion occurring at the time of starting. Even if the vibration combustion occurs, the influence of the vibration combustion can be attenuated at the damper portion, so that the influence on the blower and the fuel supply unit can be reduced. The damper 10 is controlled in advance by calculating the time required for heating the ventilation path a3, and only when the damper 10 is started (at low temperature).
The opening degree of “0” is reduced to control so as not to vibrate.
For this purpose, a separate damper controller 11 for controlling the damper 10 may be used, or the damper 10 itself may have a control function using a shape memory alloy or the like.

The second embodiment is different from the first embodiment in that
A temperature detector a12 is provided in the ventilation path a3 and a damper controller 11 is provided outside the combustor, and the opening of the damper 10 is gradually increased until a predetermined temperature is reached. Thus, the opening of the damper 10 can be continuously controlled.
That is, compared to the control as in the first embodiment, the fluctuation of the pressure in the ventilation path a3 can be detected more accurately, and the fluctuation becomes smoother, and the time until the steady operation can be shortened.

In the first embodiment, the damper 1
A pressure detector a13 and a pressure detector b14 are provided at appropriate positions between the blower 2 and the air blower 2 and at appropriate positions in the ventilation path b6, respectively.
The third embodiment can be configured by providing a damper controller 11 outside the combustor. Thus, the opening of the damper 10 is controlled so as to gradually increase until the differential pressure value detected by the two pressure detectors a13 and b14 becomes equal to or greater than a predetermined value. As a result, it is possible to prevent the oscillating combustion occurring at the time of starting hot water supply, and to shorten the time until the steady operation.

Although 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
The temperature may reach 00 ° C. or more, and may reach several hundred ° C. even in the ventilation path c8. For this reason, at the time of steady combustion, the smoke tube draft effect due to natural convection is greater than the increase in the viscous resistance due to the temperature rise inside the ventilation path b6 and the ventilation path c8. Become smaller. On the other hand, immediately after the start, the ventilation path b6 and the ventilation path c8 downstream of the flame outlet 4 are at room temperature, so that there is almost no smoke tube draft effect, the pressure loss becomes large, and the fuel easily vibrates and burns. 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 easily exhaust air at the time of startup and to increase the exhaust draft of the air passage b6 and the air passage c8. As a result, it is possible to prevent the oscillating combustion that occurs when the hot water supply is started. The control of the exhaust fan 15 and the time during which the ventilation path c8 is heated are obtained in advance, and during that time, the rotation of the exhaust fan 15 is set to a higher speed than during steady-state combustion to prevent oscillating combustion. For this purpose, an exhaust fan controller 18 for controlling the exhaust fan 15
Is used.

The fifth embodiment differs from the fourth embodiment in that a pressure detector c16 is provided on the inlet side of the exhaust fan 15;
Alternatively, a pressure detector d17 is provided on the outlet side of the exhaust fan 15, and an 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 when the pressure becomes equal to or lower than a predetermined value, the rotation of the exhaust fan 15 is controlled to be reduced from a high speed to a low speed. As a result, it is possible to prevent the oscillating combustion occurring at the time of starting hot water supply, and to shorten the time until the steady operation. The exhaust fan 15
It is also possible to configure so that the rotation of the motor gradually decreases 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 that the speed is high when the temperature is low and low when the temperature is high. As a result, it is possible to prevent the oscillating combustion occurring at the time of starting hot water supply, and to shorten the time until the steady operation.

In the above embodiment, the hot water supply combustor is shown.
Similar effects can be obtained when the present invention is applied to a heat exchanger for warm air or other heat exchangers for heating.

[0027]

According to the present invention, the following effects can be obtained.

The effect of the first invention is to prevent the oscillating combustion occurring at the time of startup by increasing the pressure loss at the upstream side of the flame opening at the time of startup. Even if the oscillating combustion occurs, the effect of the oscillating combustion can be attenuated at the damper portion, so that the effect on the blower and the fuel supply unit can be reduced.

In the first invention, the damper is controlled by the temperature detected by the temperature detector.
Oscillating combustion occurring at the time of startup can be smoothly prevented, and the time required for steady operation can be shortened. Also,
In the first invention, the damper is controlled by the differential pressure 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 to prevent the oscillating combustion occurring at the time of startup by increasing the exhaust draft upstream of the flame opening at the time of startup.

In the second aspect of the present invention, by detecting the pressure on the inlet side or the outlet side of the exhaust fan and controlling the exhaust fan, it is possible to smoothly prevent the oscillating combustion occurring at the time of startup and to achieve steady operation. The time to reach can be shortened. Further, in the second invention, by detecting the temperature of the inlet side or the outlet side of the exhaust fan and controlling the exhaust fan, it is possible to smoothly prevent the oscillating combustion occurring at the time of starting and to reach a steady operation. Time until

[Brief description of the drawings]

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mixing chamber 2 Blower 3 Vent path a 4 Flame port 6 Vent path b 7 Heat exchanger 8 Vent 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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F23N 3/06 F23N 5/02 F23N 5/18 F24H 1/10 303

Claims (6)

(57) [Claims] 1. A fuel supply unit, a mixing chamber for mixing room air and fuel sent from the fuel supply unit, and a blast for downstream mixing while further mixing premixed gas generated in the mixing chamber. And a ventilation path a for premixed air sent from the blower
A flame port provided downstream of the vent a, a vent b provided downstream of the flame, a heat exchanger provided in the vent b, and a vent provided downstream of the heat exchanger c) in the combustor with a heat exchanger of the all-primary combustion type, a damper is provided in the ventilation path a located between the blower and the flame port, and the opening degree of the damper is reduced at the time of startup. A combustor with a heat exchanger, comprising a damper controller for setting. 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 degree of opening of the damper based on the temperature detected by the temperature detector. 3. A pressure detector is provided in each of a proper position of the ventilation path b and a proper position between the damper and the blower, and the operation of the damper is controlled by a differential pressure between the pressures detected by the two pressure detectors. The combustor with a heat exchanger according to claim 1, wherein the damper controller is configured as described above. 4. A fuel supply unit, a mixing chamber for mixing room air with fuel sent from the fuel supply unit, and a blower for downstream mixing while further mixing premixed gas generated in the mixing chamber. And a ventilation path a for the premixed gas sent from the blower
A flame port provided downstream of the ventilation port a, a ventilation path b provided downstream of the flame port, a heat exchanger provided downstream of the ventilation path b, and a ventilation provided downstream of the heat exchanger. In a combustor with a heat exchanger of the all-primary combustion type having the path c, an exhaust fan is provided in the ventilation path c, and an exhaust fan controller that controls the operation of the exhaust fan so that the exhaust fan rotates at high speed at startup is provided. A combustor with a heat exchanger. 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 the rotation of the exhaust fan based on a pressure detected by the pressure detector. With combustor. 6. The heat generator according to claim 4, wherein a temperature detector is provided at an inlet side or an outlet side of the exhaust fan, and the exhaust fan controller is configured to control rotation of the exhaust fan based on a temperature detected by the temperature detector. Combustor with exchanger.