JPH02293519A - Ignition sound reducing device of forced ventillation type hot air heater - Google Patents

Abstract

PURPOSE:To reduce an ignition sound and further prevent mixed gas from returning back to a burner by a method wherein in case of ignition, an air supplying fan is controlled, an amount of supplied air for a combustion chamber is set to a higher state, a fuel pump is controlled and a control means for making an amount of fuel supplied to the combustion chamber to a lower stage is provided. CONSTITUTION:An ignition sound reducing device is provided with an air supplying fan 2b for feeding air in a stepwise manner to a combustion chamber 3 and a fuel 2f for feeding fuel to the combustion chamber 3 in a stepwise manner. In case of ignition, a control means 10 is provided for controlling the air supplying fan 2b to make an amount of supplied air to the combustion chamber 3 to a higher stage and then for controlling a fuel pump 2f to make an amount of supplied fuel for the combustion chamber 3. In case of ignition, the control means 10 may control the fuel pump 2f to make an amount of supplied fuel to the combustion chamber 3 to a lower stage and then an expansion caused by the combustion of the mixed gas in the combustion chamber 3 is reduced. The air supplying fan 2b is controlled to make an amount of air supplied to the combustion chamber 3 to a higher stage and further an inverse flow of flame from the combustion chamber 3 is enclosed, so that even in case of a machine having a small amount of combustion, an ignition sound can be reduced and further the mixed gas is prevented from returning back to the combustion equipment.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention relates to an ignition noise reduction device for semi-enclosed and closed forced air supply/exhaust type warm air heaters, and more specifically, to The present invention relates to an ignition noise reduction device for a forced air supply/exhaust hot air heater that prevents the generation of fire and enables quiet and stable combustion startup.

Problems to be solved by conventional technology and invention〉Commonly known as FF
Forced air supply and exhaust type hot air heaters, also known as type stoves, use holes or windows in the wall to expose the air supply and exhaust ports of the supply and exhaust pipe to the outdoors, and the air supply and exhaust ports are connected to the interior of the room. Combustion air is forcibly supplied into the sealed combustion chamber using a combustion blower, and the mixture of the combustion air and the fuel blown out from the nozzle of the burner built into the combustion chamber is ignited. The combustion gas is then discharged outdoors through the exhaust port. - Cool indoor air is forcibly blown around the combustion chamber heated by combustion heat using a convection blower, and converted into warm air through a heat exchanger interposed between the combustion chamber and the exhaust stack. This increases the temperature inside the room.

In the above-mentioned forced air supply and exhaust hot air heater, when igniting,
The air-fuel mixture in the combustion chamber rapidly expands and becomes a high-speed flow that attempts to escape outdoors through the supply and exhaust stacks, but this is suppressed by the pipe resistance piles of the supply and exhaust stacks, resulting in high pressure inside the combustion chamber. . When this high-pressure gas mixture moves back and forth at high speed through the openings provided around the burner, a large vibration noise (so-called combustion vibration) is generated. Additionally, there was a problem in that backfire noise was generated as a result of the mixed gas returning to the nozzle side of the burner.

In view of these problems, various devices have been considered to reduce ignition noise.

Figure 6 is a diagram showing a conventional burner, which is used in models with a large combustion amount, and is equipped with an air supply fan (51) in a duct (51) facing the combustion chamber (50).
52), ignition nozzle (53), main combustion nozzle (54)
), and an ignition solenoid valve (55) and a main combustion solenoid valve (5B) are connected to the ignition nozzle (53) and main combustion nozzle (54), respectively.

In this burner, when igniting, the ignition nozzle (
By injecting fuel from 53) into the combustion chamber (50), ignition noise is reduced by reducing the amount of fuel supplied and igniting. Also, during the main combustion, the main combustion nozzle (
By injecting fuel from 54) into the combustion chamber (5o), the thermal power can be increased.

However, the two-stage combustion method described above cannot be applied to models with a small combustion amount. This is because when the two-stage combustion method is applied to a model with a small combustion amount, it is necessary to reduce the diameter of the ignition nozzle, which causes the problem that the nozzle is easily clogged.

In addition, the nozzle placed in the duct is integrated, and the voltage applied to the fuel pump is controlled by Cyrisk to gradually increase, igniting when the discharge pressure of the fuel pump reaches a predetermined value, and the discharge pressure increases further. A method is being considered in which the main combustion occurs when the rated pressure is reached. However, when the combustion chamber and the heat exchanger are downsized, there is a problem in that a sufficient ignition noise reduction effect cannot be achieved.

Furthermore, simply controlling the fuel supply amount cannot completely prevent the mixed gas from returning to the burner side.
There is a risk of causing a packfire, and there is also the problem that soot adheres to the ignition plug, flame sensor, etc., causing leakage of the ignition plug and poor sensitivity of the flame sensor.

In view of the above-mentioned problems, this invention is a forced air supply/exhaust type hot air heater that can reduce ignition noise and prevent the mixed gas from returning to the burner side even in models with a small combustion amount. The purpose of this invention is to provide an ignition noise reduction device for aircraft.

Means for Solving the Problems> To achieve the above object, the ignition noise reduction device for a forced air supply/exhaust hot air heater according to the present invention includes an air supply fan (C3) that feeds air in stages into the combustion chamber (C3). 2b》 and combustion chamber (3)
and a fuel pump (2f) that feeds fuel in stages, and further controls the air supply fan (2b) at the time of ignition to increase the amount of air supplied to the combustion chamber (3), It has a control means (10) that controls the pump (2f) to lower the amount of fuel supplied to the combustion chamber G).

According to the ignition noise reduction device for a forced air supply and exhaust hot air heater configured as described above, when igniting, the control means (10) controls the fuel pump (2') to blow the combustion chamber (3'). ), it is possible to reduce the expansion due to combustion of the mixed gas in the combustion chamber (3).Furthermore, by controlling the air supply fan (2b), the amount of fuel supplied to the combustion chamber (3) can be reduced. 》 By setting the air supply amount to a high level, the backflow of flame from the combustion chamber (3) can be contained by air, so even with models with a small combustion amount, the ignition noise can be reduced. At the same time, it is possible to prevent the mixed gas from returning to the combustor side.

Example Embodiments will be described in detail below with reference to the accompanying drawings showing examples.

FIG. 2 is a schematic configuration diagram showing an embodiment of the ignition noise reduction device for a forced air supply/exhaust hot air heater of the present invention, and FIG. 1 is an enlarged view of the combustion device and a connection diagram with a control board. .

In the figure, this forced air supply/exhaust hot air heater (A) is
Inside the casing (1), there is an air supply chamber (B) and a heat exchange chamber (C).
and a fan room (D), and an air supply room (B)
A combustion device (2) is disposed in the heat exchange chamber (C), a combustion chamber (3) and a heat exchanger (4) are disposed in the heat exchange chamber (C), and a convection fan is disposed in the fan chamber (D). (5) is installed.

Furthermore, the supply cylinder (6) communicating with the combustion device (2) and the exhaust cylinder (7) communicating with the heat exchanger (4) are configured as double cylinders (11) and are exposed to the outdoors. Furthermore, the fan room (D) is provided with a suction grill (8) for sucking indoor air, and the heat exchange room (C) is provided with an outlet grill (9) for blowing out warm air indoors. ing.

A control board (10) (see FIG. 1) that controls the combustion device (2) and adjusts the fuel supply amount and air supply amount in stages is provided at a suitable location in the casing (1).

As shown in Fig. 1, the combustion device (2) is connected to the air supply side or to the supply cylinder (6), and the air supply side is connected to the side wall (3a) of the combustion chamber (3).
It has a duct (2a) that communicates with an opening (3b) provided in the duct (2a), and inside this duct (2a), an air supply fan (2b), a nozzle (2c), a spark plug (2d), and a flame detection sensor (
2e), and the above nozzle (2a) is placed outside the duct (2a).
2c), a combustion pump (2f) that discharges fuel, a fuel supply path (2g), an ignition transformer (2h) that applies high voltage to the ignition plug (2d), and an electromagnetic relay (21). be.

The combustion pump (2f) includes an electromagnetic pump (2j) connected to the fuel supply path (2g), a bypass path (2k) that bypasses the fuel supply path (2g), and this bypass W! (
It has a solenoid valve (2L) that opens and closes the control board (2k).
The electromagnetic valve (2L) is opened and closed according to the driving voltage from the electromagnetic pump (2L), and the amount of fuel supplied to the electromagnetic pump (2L) is adjusted in stages.

In addition, the normally open contact (2+n) of the electromagnetic relay (2I) is connected to the drive coil of the electromagnetic relay (2I), and the normally closed contact (2n) is connected between the control board (10) and the electromagnetic valve (2L). Intervening connection.

The combustion chamber (3) is a chamber in which fuel injected from the nozzle (2c) is combusted, and as shown in FIG.
) from the top of the side wall (3a) to the heat exchanger (4),
The exhaust passage (3c) is connected to the exhaust passage (3c), and the combustion gas that burns in the combustion chamber (3) and becomes high temperature is transferred to the exhaust passage (3c).
is sent to the heat exchanger (4) through the heat exchanger (4). The outlet portion (4a) of the heat exchanger (4) is communicated with the exhaust pipe (7).

The control board (10) has a drive terminal (log) (job)
(10c) (10d), has an input terminal (foe), an air supply fan (2b), a fuel pump (2f),
A control circuit for sequence control of the ignition transformer <<2h>> etc. is incorporated. An air supply fan (2b) is connected to the drive terminal (<10a), an electromagnetic pump (2j) is connected to the drive terminal (10b), and the drive terminal (10c)
includes an ignition transformer (2h) and an electromagnetic relay (2l)
is connected, and a solenoid valve (2L) is connected to the drive terminal (10d). Further, a flame sensor (2e) is connected to the input terminal (10e).

FIG. 3 is a schematic diagram of input/output timing and input/output voltage of the control board (10).

In the figure, S is a start pulse that starts this forced air supply/exhaust hot air heater (A), and a is a drive terminal (10a
) shows the drive voltage supplied to the air supply fan (2b), and is set in two levels, high and low, to adjust the amount of air supplied to the combustion chamber (3). b indicates the drive voltage supplied from the drive terminal (tab) to the electromagnetic pump (2j), and the rise is made more gradual than that of a phase control circuit (not shown) to prevent fuel from being suddenly discharged at the time of ignition. C indicates a drive pulse supplied from the drive terminal (toe) to the electromagnetic relay (21) and the ignition transformer (2h). d is the drive terminal (lod) and the normally closed contact (2n) of the electromagnetic relay (2I).
) shows the low combustion adjustment signal provided through the e is a flame detection signal supplied to the input terminal (toe) from the flame sensor (2e).

Next, the operation of this ignition noise reduction device will be explained using the pressure characteristic diagram of the electromagnetic pump (2j) in Figure 4 and the combustion chamber (3) in Figure 5.
The explanation will be based on the pressure characteristic diagram shown below.

When the start pulse S is input to the control board (10),
The control board (10) supplies the high-level drive voltage a from the drive terminal (10a) to the air supply fan (2b), and
Air is fed into the combustion chamber (3) through. That is, in order to prevent backflow in the combustion chamber (3), the shutoff pressure (Pi in FIG. 5) applied to the combustion chamber (3) is made high. In addition, the cut-off pressure when low-stage drive voltage a is supplied (P1' in Figure 5)
becomes lower.

After the start pulse S is input and a certain period of time has elapsed,
The drive pulse C is sent from the drive terminal (10c) to the electromagnetic relay (2
l) and the ignition transformer (2h), and the drive voltage b is supplied from the drive terminal (10b) to the electromagnetic pump (2j).
supply to.

The electromagnetic relay (2l) that receives the drive pulse C has a normally open contact (
2a+) is closed and a driving pulse C is supplied to the solenoid valve (2L). Therefore, the electromagnetic valve (2L) is opened and fuel flows into the fuel supply path (2g) and the bypass path (2k), so the amount of fuel supplied to the electromagnetic pump (2j) is small.

On the other hand, the electromagnetic pump (2j) receiving the driving voltage b pumps fuel from the fuel supply path (2g) and the bypass path (2k) to the nozzle (2j) at a discharge pressure proportional to the rise of the driving voltage b.
2C). From this, the discharge pressure of the electromagnetic pump (2j) approaches the saturated state P3 as shown in FIG.
While the drive pulse C is being output (from the origin to T2 in Figure 4), the bypass passage (2k) is open, so the amount of fuel supplied to the combustion chamber (3) is in a low stage state. It is.

The ignition transformer (2h) that receives the drive pulse C makes the potential high and then applies it to the ignition plug (2d). The output timing of this applied voltage requires time to raise the drive pulse C to a high potential, and the ignition timing requires the drive pulse C
It is delayed by time T from the rise of .

Then, the mixture in the combustion chamber (3) becomes high pressure due to the young flame, and this mixture tries to flow back into the opening (3b) of the combustion chamber (3), but the amount of fuel supplied at the time of ignition is small. , the maximum value of ignition pressure (point P2 in Fig. 5) is the maximum value of ignition pressure (point P2 in Fig. 5) when ignition occurs without restricting the fuel supply amount (
(point P2' in FIG. 5).

Moreover, the air supply fan (2b)
By driving the combustion chamber (3), air is supplied at high pressure into the combustion chamber (3), and the cut-off static pressure applied to the combustion chamber (3) is kept high (PI in Fig. 5). 3) can block the air-fuel mixture flowing back into the opening (3b). That is, by preventing combustion vibrations generated at the opening (3b) during ignition, excessive noise during ignition can be reduced. In addition, by preventing the backflow of the air-fuel mixture, backfire can be reliably prevented, and the ignition plug (2d) and flame sensor (2e
) etc. can be prevented from adhering to soot. Therefore, leakage of the ignition plug (2d) due to soot adhesion and flame sensor (
2e) poor sensitivity can be prevented.

Next, the flame sensor (2e) detects the ignition and supplies a flame detection signal to the input terminal (10e) of the control board (10).

Next, the drive pulse C falls and the electromagnetic relay (2
1) and the ignition transformer (2h) are stopped,
The normally open contact (2m) of the electromagnetic relay (21) is OFF.
The normally closed contact (2n) is turned on. Therefore, the solenoid valve (2L)
Since the supply of electricity to the electromagnetic pump (2j) is stopped and the bypass passage (2k) is closed, the amount of fuel supplied to the electromagnetic pump (2j) becomes high. From the time when the above operations are completed (72 in FIG. 4), the main combustion operation begins.

In addition, after receiving the flame detection signal and recognizing ignition, the control board (10) also controls the flame holding time (9) to prevent misfire after ignition.
The drive voltage a (high stage) is supplied to the air supply fan (2b) for 0 seconds) to increase the amount of air supplied.

After the flame holding time ends, the temperature is adjusted according to the room temperature.

That is, when the room temperature rises, a low-level drive voltage b is supplied from the terminal (10a) to the air supply fan (2b), and a low combustion adjustment signal d is supplied from the terminal (10d) to the solenoid valve. Since the amount of fuel supplied to the pump (2j) is reduced, the temperature inside the combustion chamber (3) can be lowered. On the other hand, when the room temperature drops, the high-level drive voltage a is supplied from the terminal (10a) to the air supply fan (2b), and when the electromagnetic valve (2L) is de-energized, the electromagnetic pump (
2j) increases the amount of fuel supplied to the combustion chamber (3).
can increase the internal temperature.

Effects of the Invention> As described above, according to the ignition noise reduction device for a forced air supply and exhaust hot air heater according to the present invention, when igniting, the control means (
10) controls the fuel pump (2f) to open the combustion chamber (3).
By reducing the amount of fuel supplied to the combustion chamber (3
), and by controlling the air supply fan (2b) to increase the amount of air supplied to the combustion chamber (3), the flame from the combustion chamber (3) is reduced. Since backflow is contained by air, ignition noise can be reduced even in models with a small combustion amount. In addition, by preventing the backflow of the mixed gas, it is possible to prevent packfires and soot from adhering to the ignition plug (2d), flame sensor (2e), etc.
leakage and poor sensitivity of the flame sensor (2e) can be prevented.

[Brief explanation of the drawing]

Fig. 1 is an enlarged view of the combustion device and a connection diagram with the control board, Fig. 2 is a schematic configuration diagram showing an embodiment of the ignition noise reduction device for a forced air supply/exhaust hot air heater of the present invention, and Fig. 3 4 is a schematic diagram of the input/output timing and input/output voltage of the control board, FIG. 4 is a discharge pressure characteristic diagram of an electromagnetic pump, FIG. 5 is a pressure characteristic diagram in the combustion chamber, and FIG. 6 is a diagram showing a conventional burner. (10)...Control board (2b)...Air supply fan, (2f)...Fuel pump, (2g)...Fuel supply path, (2h)...Bypass path, (21)...・・Electromagnetic relay No. 2 time

Claims (1)

[Claims] 1. The air supply fan (2b) and the fuel pump (2f) are controlled to adjust the air supply amount and fuel supply amount to the combustion chamber (3) in stages, In a forced air supply/exhaust hot air heater that burns a mixture of air and fuel in the chamber (3), the air supply fan (2b) is controlled at the time of ignition to control the amount of air supplied to the combustion chamber (3). Along with increasing the level of
Ignition noise reduction device for a forced air supply/exhaust hot air heater, characterized by comprising a control means (10) that controls the fuel pump (2f) to lower the amount of fuel supplied to the combustion chamber (3). .