JP3538974B2 - Forced combustion 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 forced combustion apparatus for forcibly feeding combustion air to a burner to perform combustion, and more particularly, to increasing a primary air ratio with an increase in the amount of combustion. The present invention relates to a forced combustion device which can obtain good combustion characteristics with a large turndown ratio.

[0002]

2. Description of the Related Art In a forced combustion apparatus, fuel gas is supplied from a fuel gas supply line, and combustion air is forcibly fed to a burner by an air supply means such as a blower fan to perform combustion. . Here, a part of the air pumped into the combustion device by the blower fan enters the burner from the burner inlet together with the fuel gas ejected from the nozzle of the gas line, mixes with the fuel gas, and travels to the flame outlet. The remaining air becomes secondary air that passes through the outside of the burner to reach the combustion position and contributes to combustion.

Here, the total amount of combustion air is controlled so as to have a fixed ratio to the fuel gas input amount. Therefore, the ratio of the primary air and the secondary air to the gas input amount is determined by the resistance of each air passage. , And the passage resistance is mainly determined by the shape of the air passage. In the conventional combustion apparatus, the passage resistance is uniquely determined, and the ratio of the primary air to the supply amount is almost constant regardless of the input amount of the fuel gas. It had the characteristic that the ratio of primary air to air amount increased. This combustion apparatus aims to reduce the dew point of the combustion gas by increasing the amount of air in order to prevent a problem of dew condensation at the time of a small input with a relatively low burner temperature.

[0004]

However, the forced combustion device according to the above prior art has the following problems.

That is, for example, if a setting is made so that the ratio of the primary air to the supply air amount becomes about 50% at the time of 100% input while giving importance to the combustion characteristics at the time of large input, the input is reduced to about 20%. It is not preferable because the primary air sometimes becomes excessive and the combustion flame back phenomenon or lifting occurs. On the other hand, if the setting is made so that the primary air ratio is about 20% at the time of 20% input while giving importance to the combustion characteristics at the time of small input, the input can be reduced to 10%.
When it is increased to near 0%, primary air becomes insufficient, and poor combustion such as incomplete combustion occurs. Therefore, there is a problem that the input range in which a good combustion state is obtained is narrow regardless of the setting.

[0006] In order to solve the problems of the prior art, the present invention has been broadened by providing such a characteristic that the primary air ratio is increased or the secondary air ratio is decreased as the gas input increases. It is an object of the present invention to provide a forced combustion device capable of uniformly obtaining good combustion in an input range. It is another object of the present invention to provide a forced combustion device that performs control to decrease the passage resistance of the primary air as the gas input increases. Alternatively, it is another object of the present invention to provide a forced combustion device having a characteristic in which the passage resistance of the secondary air increases as the gas input increases.

[0007]

SUMMARY OF THE INVENTION The present invention provides a burner,
Gas amount adjusting means for adjusting the gas supply amount to the burner ,
Forced combustion apparatus having a blower fan for supplying combustion air
And controlling the blowing fan to supply combustion air.
Where the supply amount is relative to the gas supply amount by the gas amount adjustment means.
Fan control means for maintaining the temperature within a predetermined allowable range;
As the combustion air supply by the fan increases, the burner
Secondary air reduction means for reducing the secondary air ratio of
In addition, the secondary air reducing means is configured to reduce the secondary air of the burner.
It has two ventilation plates in which ventilation holes are formed,
The upstream ventilation plate is an elastic member with respect to the downstream ventilation plate.
Are arranged side by side at predetermined intervals through the
The interval decreases with the increase of combustion air supply
To increase the secondary air passage resistance of the vent hole.
That is the gist.

[0008] The present invention further provides a burner and a burner for the burner.
Gas amount adjusting means for adjusting the gas supply amount, and combustion air
In the forced combustion device having a blower fan for supplying,
By controlling the blower fan, the supply amount of combustion air is
Predetermined range for the gas supply amount by the gas amount adjustment means
Fan control means to maintain the inside of the
The secondary air ratio of the burner increases with the supply of combustion air.
Secondary air reducing means for reducing the rate of secondary air.
The air reducing means includes a vent as a secondary air passage of the burner.
Having a plurality of ventilation plates formed with
As the amount of combustion air supplied by the blower fan increases,
At regular intervals, the passage resistance of the secondary air through the pores increases.
The gist is that it is established.

In this case, the juxtaposed and adjacent
The ventilation holes formed in the ventilation plate face each other.
It is good to be provided in a position where there is no. Or the ventilation
The opening shape of the vent hole of the plate is narrow on the upstream side of the secondary air and downstream
It is good to form so that a side may become large.

The present invention relates to a burner and a burner.
Gas adjusting means for adjusting the gas supply amount of the combustion air
Of forced-combustion device with blower fan for supplying air
Controlling the blower fan to increase the supply amount of combustion air.
Predetermined allowance for gas supply amount by the gas amount adjustment means
Fan control means for maintaining the temperature within the range;
As the combustion air supply increases due to the
Secondary air reduction means for reducing the air ratio.
The secondary air reducing means includes a secondary air passage for the burner.
It has a ventilation plate with a plurality of pores.
Rotational component is added to the secondary air passing through the ventilation hole on the downstream side of the mouth.
By providing a rectifying plate at an angle,
With the increase in the supply of combustion air by the fan,
The main point is to increase the passage resistance of the secondary air.
You.

[0011]

According to the forced combustion apparatus of the present invention having the above-described structure, the combustion air is supplied by the blower fan, and the gas supplied to the burner via the gas amount adjusting means is burned. Here, the supply amount of the combustion air is maintained within a predetermined allowable range with respect to the gas supply amount by the gas amount adjustment unit by the fan control unit. And for combustion with gas supply
When the supply of air increases, the supply of combustion air
Secondary air that passes through the outside of the burner and reaches the combustion section as it increases
Is formed as a passage for the secondary air of the burner.
Reduced by the secondary air reduction means having a closed ventilation plate
As a result, the ratio of primary air increases and good combustion is performed.
It is supposed to be.

That is, the ventilation as a passage of the secondary air of the burner.
The upstream ventilation plate of the two ventilation plates with holes
Leave a predetermined distance from the ventilation plate on the flow side via an elastic member.
Increase the supply of combustion air by the blower fan
In addition, the space becomes narrower, so that the secondary air flows through the vent hole.
If the road resistance is increased, the upstream and downstream sides
By the passive action of the two ventilation plates and the elastic body,
As the air supply for combustion by the fan increases,
The secondary air passage resistance of the formed ventilation hole is increased to
Acts as secondary air reduction means to reduce the secondary air ratio
You.

Also, a vent as a passage for secondary air of the burner.
Combustion of multiple ventilation plates with air blower fan
As the amount of air supply increases, the passage resistance of the secondary air in the ventilation holes increases.
If they are juxtaposed at large intervals, the flow rate of secondary air
Passage resistance is small when the flow rate is small, and
As road resistance increases to reduce the secondary air ratio
Acts as secondary air reducing means.

In this case, the adjacent ventilation plates are formed side by side.
The ventilation holes that have been
With this configuration, the combustion air
Changes in the secondary air passage resistance of the ventilation holes due to the increase in air supply
It is possible to further increase the size. Also the ventilation plate
The opening shape of the vent hole of the secondary air is narrow on the upstream side and downstream
If the configuration is made so that
As the air passes through the vent, for example,
The vortex generated by peeling off at the edge of the hole becomes more pronounced,
A contraction occurs in the flow of the secondary air and interferes with the flow.
To effectively increase the secondary air passage resistance
it can.

The vent hole is located downstream of the opening of the vent hole.
Rectifier plate that gives rotation component to secondary air passing through
In this configuration, the secondary air passage shape is
When the air velocity is low, the passage resistance is low and the flow velocity is high.
When the passage is large, the secondary air ratio
Acts as secondary air reduction means to reduce the rate.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A forced combustion device according to the present invention will be described below in detail with reference to embodiments shown in the drawings.

First, a reference example will be described with reference to FIGS. The forced combustion device 1 according to the reference example shown in FIG. 1 is generally configured by disposing a gas burner 3, a blower fan 4, and a heat exchanger 5 in a machine frame 50.

A gas port 3a is formed in the upper part of the gas burner 3, and a primary air port 3b is formed in the lower part. Then, facing the primary air port 3b of the gas burner 3,
A gas nozzle 8 for ejecting a fuel gas G supplied from a gas supply pipe 7 is provided. The gas supply pipe 7 is provided with a shutoff valve 9 for shutting off gas supply and a proportional valve 10 for adjusting the gas supply amount.

The primary air port 3b of the gas burner 3 is provided with a damper plate 12 and a damper motor 13. The damper plate 12 is provided with an opening 12 a in a substantially fan-shaped plate, as shown in the view of the arrow A in FIG. 2, and is rotatable about a shaft 14. On the opposite side of the opening 12a, the tooth 1
2b is formed and meshed with the motor gear 15 coaxial with the damper motor 13. That is, the damper plate 12
Is to cover the primary air port 3b of the gas burner 3 and to reduce the effective opening area of the primary air to the overlapping area of the primary air port 3b and the opening 12a. When the damper motor 13 rotates the damper plate 12, The overlapping area changes to change the primary air passage resistance.

The blower fan 4 is an electric fan rotated by a motor, and forcibly discharges combustion air.
It is sent into the inside. A part of the combustion air sent by the blower fan 4 enters the primary air port 3b of the gas burner 3 together with the fuel gas G.
The remainder is the secondary air S that passes through the outside of the gas burner 3 and reaches the flame F. At the position between the primary air port 3b and the flame port 3a of the gas burner 3 inside the machine frame 50, a ventilation plate 17 for making the distribution uniform is fixed and provided. A large number of ventilation holes 17a as passages for S are formed so as to have appropriate passage resistance.

Heat exchanger 5 located above gas burner 3
Is for heating the water C supplied to the water supply pipe 52 with the flame F of the gas burner 3 to discharge the water from the tapping pipe 54. The water supply pipe 52 is provided with a flow sensor 53, and the tapping pipe 54 is provided with a thermistor 55. An exhaust pipe 51 for discharging the combustion exhaust gas E is attached to an upper end of the machine frame 50 above the heat exchanger 5.

A controller 20 for controlling the forced combustion device 1 is provided. The controller 20 is a microcomputer formed by combining a known CPU, ROM, and RAM, receives signals from a flow sensor 53, a thermistor 55, a remote controller (not shown), and shuts off a valve 9, a proportional valve 10, a blower fan 4, A drive signal is sent to the damper motor 13.

The main control function of the controller 20 is to control the amount of gas supply by controlling the opening of the proportional valve 10 so that the tapping temperature detected by the thermistor 55 becomes a desired value, thereby controlling the amount of heat generated by the gas burner 3. Temperature control function,
An air ratio maintaining function that adjusts the rotation speed of the blower fan 4 in accordance with the opening of the proportional valve 10 to maintain the supply amount of combustion air within a predetermined allowable range with respect to the gas supply amount. At the same time, the damper motor 13 is driven to drive the damper plate 1.
There is a primary air ratio adjustment function for adjusting the position of No. 2 and adjusting particularly the amount of primary air among the combustion air.

Next, the operation of the forced combustion device 1 will be described. When the flow sensor 53 detects the water flow in the water supply pipe 52, the fact is input to the controller 20. Then, the controller 20 opens the shut-off valve 9 according to the hot water supply request, supplies the fuel gas G to the gas burner 3 and rotates the blower fan 4 to supply the combustion air.

A part of the combustion air enters the gas burner 3 from the primary air port 3b of the gas burner 3 together with the fuel gas G as the primary air P, is mixed with the fuel gas G, and enters the gas burner 3a through the flame port 3a. Outflow of 3 The rest,
As the secondary air S, the gas passes through the outside of the gas burner 3 and joins with the mixed gas of the primary air P and the fuel gas G flowing out from the flame opening 3 a of the gas burner 3. Then, the fuel gas G is burned by the primary air P and the secondary air S to form a flame F. The water C is heated by the heat exchanger 5 by the generated heat of the flame F, and the hot water H flows out of the tapping pipe 54.

At this time, the controller 20 adjusts the opening of the proportional valve 10 based on the tapping request and the temperature detected by the thermistor 55. This is because the amount of the fuel gas G supplied to the gas burner 3 is adjusted to increase or decrease the amount of heat generated by the flame F, so that the detected temperature of the thermistor 55 matches the required temperature. Therefore, when the required temperature is high, the opening of the proportional valve 10 is increased so that a sufficient amount of heat is obtained, and when the required temperature is low, the opening of the proportional valve 10 is narrowed down.

At the same time, the controller 20 adjusts the rotation speed of the blower fan 4 in accordance with the opening of the proportional valve 10. This is to prevent the shortage or excess of the combustion air by maintaining the supply amount of the combustion air within a predetermined allowable range for the gas supply amount. Therefore, when the required temperature is high and the opening of the proportional valve 10 is increased, the rotation speed of the blower fan 4 is increased so that sufficient combustion air is supplied.
When the opening of 0 is narrowed, the rotation speed is reduced.

The controller 20 further controls the damper motor 1 according to the opening of the proportional valve 10 and the rotation speed of the blower fan 4.
3 to adjust the position of the damper plate 12 so that the primary air P
Increase or decrease the effective opening area of Primary air P mixed with fuel gas G in the gas burner 3 among the combustion air
The reason for this is that the combustion speed is greatly affected, and if this is not within an appropriate range, the back phenomenon of the flame F into the gas burner 3 and other abnormal combustion occur.

Therefore, when the opening of the proportional valve 10 is large and the rotation speed of the blower fan 4 is high, the primary air port 3b of the gas burner 3 and the opening 12a of the damper plate 12 almost coincide, and the effective opening area is large. The passage resistance of the primary air P is set to a small state. This is because the supply amount of the fuel gas G is large, so that the primary air ratio is increased to prevent poor combustion such as incomplete combustion. On the other hand, the opening of the proportional valve 10 is small,
When the rotational speed of the gas burner 3 is low,
Most of b is closed by the damper plate 12 so that the effective opening area is small and the passage resistance of the primary air P is large. This is to prevent a back phenomenon of the flame F due to an excessive amount of the primary air P because the supply amount of the fuel gas G is small.

That is, in the forced combustion device 1, the damper plate 12 and the damper motor 13 act as primary air ratio increasing means for increasing the supply amount of combustion air and increasing the primary air ratio. Accordingly, a forced combustion device capable of burning at an appropriate primary air ratio regardless of whether the supply amount of the fuel gas G is large or small is realized.

Next, a first embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The forced combustion device 2 of the first embodiment shown in FIG. 3 is generally the same as the forced combustion device 1 of the reference example in that a gas burner 3, a blower fan 4, and a heat exchanger 5 are arranged in a machine frame 50. Therefore, in the following description, the same parts are denoted by the same reference numerals, and the description will focus on the differences from the forced combustion apparatus 1. The difference in the configuration of the forced combustion device 2 from the forced combustion device 1 is that the damper plate 12 and the damper motor 13 are not provided, and that the forced ventilation device 17 is attached to the ventilation plate 17.
Are provided via the spring 21. There is no particular difference in other respects.

The ventilation plates 17 and 18 will be described with reference to the enlarged view of FIG. The ventilation plate 17 is fixed to the machine frame 50 similarly to that of the forced combustion device 1, and has a large number of ventilation holes 17 a serving as a passage for the secondary air S. On the other hand, the ventilation plate 18 is attached to the ventilation plate 17 via the spring 21 and is not fixed to the machine frame 50. The spring 21 provides an appropriate interval W between the ventilation plates 17 and 18. The spring 21 is compressed and shortens the interval W when the pressure T of the combustion air sent by the blower fan 4 increases. Similarly to the ventilation plate 17, the ventilation plate 18 has a large number of ventilation holes 18a serving as passages for the secondary air S, but the ventilation holes 18a are formed at positions not opposed to the ventilation holes 17a.

In this case, the passage resistance of the secondary air S is the distance W
The smaller the is, the larger it is. That is, the ventilation plates 17 and 18
Is configured such that the passage resistance of the secondary air S changes according to the pressure T of the combustion air. On the other hand, primary air P
Since the damper plate 12 is not provided,
It does not vary with the supply of combustion air. Since the damper motor 13 is not provided, the control function of the damper motor 13 in the controller 20 is omitted.

Next, the operation of the forced combustion device 2 will be described. Since the basic operation is the same as the operation of the forced combustion device 1, only the difference between the primary air ratio and the secondary air ratio will be described. Although the forced combustion device 2 does not change the passage resistance of the primary air P, the passage resistance of the secondary air S changes due to the action of the spring 21.

That is, when the opening of the proportional valve 10 is large and the number of rotations of the blower fan 4 is high, that is, when the pressure T of the combustion air is large, the spring T is compressed by the pressure T and the pressure between the ventilation plates 17 and 18 is reduced. The interval W is reduced, and the passage resistance of the secondary air S is increased. For this reason, the secondary air ratio decreases and the primary air ratio increases accordingly. Thereby, the amount of primary air is increased, and even if the supply amount of the fuel gas G is large, poor combustion such as incomplete combustion does not occur.

On the other hand, when the opening of the proportional valve 10 is small and the rotation speed of the blower fan 4 is low, that is, when the pressure T of the combustion air is small, the elasticity of the spring 21 is superior and the spring 21 expands and the ventilation plate 17 The distance W between the secondary air S and the passage 18 increases, and the passage resistance of the secondary air S decreases. For this reason, the secondary air ratio increases and the primary air ratio decreases accordingly. As a result, the amount of the primary air is reduced, and even if the supply amount of the fuel gas G is small, the back phenomenon of the flame F due to the excess of the primary air P does not occur.

That is, the forced combustion device 2 includes a damper motor 13 controlled by the controller 20 in the forced combustion device 1.
Although the air passage resistance is not increased or decreased by an active method such as driving of the air, the supply amount of the combustion air is increased due to the passive action of the ventilation plates 17 and 18 and the spring 21 and the pressure T is increased.
And the passage resistance of the secondary air S increases 2
The primary air ratio is increased in response to the decrease in the secondary air ratio. This realizes a forced combustion device that can burn at an appropriate primary air ratio regardless of whether the supply amount of the fuel gas G is large or small.

Next, a second embodiment of the present invention will be described with reference to FIGS. The forced combustion device 6 according to the second embodiment shown in FIG. 5 generally comprises a machine frame 50 provided with a gas burner 3, a blower fan 4, and a heat exchanger 5, and a ventilation plate 17 serving as a secondary air ratio reducing means. First in that it comprises
It is common to the forced combustion device 2 of the embodiment. Therefore, in the following description, common parts use the same reference numerals, and the forced combustion device 2
The following description focuses on the differences from FIG.

The constructional difference between the forced combustion device 6 and the forced combustion device 2 is that the ventilation plates 17 and 18 are fixed to the machine frame 50 and the spring 21 is not provided. . Therefore, in the forced combustion device 6, the distance D between the ventilation plates 17 and 18 is a fixed value. In the forced combustion device 6, the ventilation holes 17a and 18a of the ventilation plates 17 and 18 are provided at positions facing each other. In FIG. 5, the ventilation plate 17,
18 is provided at a part of the gas burner 3 at a position lower than the primary air port 3b, and a partition 26 is provided above the primary air port 3b.
This is different from the forced combustion device 2 in that the primary air P does not pass through the ventilation plates 17 and 18 and the secondary air S passes through the ventilation plates 17 and 18. This is not substantially different from the arrangement of the ventilation plates 17 and 18 in the case of the forced combustion device 2.

Next, the operation of the forced combustion device 6 will be described. Since the basic operation is the same as the operation of the forced combustion device 2, only the operation of changing the secondary air ratio, which is the difference, will be described. In the forced combustion device 6, the passage resistance naturally changes according to the flow velocity of the secondary air S according to the passage shape of the secondary air S.

That is, when the opening of the proportional valve 10 is small and the rotation speed of the blower fan 4 is low, that is, when the flow velocity of the combustion air is small, the secondary air S is supplied to the vent hole 17 as shown in FIG.
a, the passage resistance of the secondary air S is small because the swirl hardly occurs by passing through the air smoothly. For this reason, the secondary air ratio increases and the primary air ratio decreases accordingly. This gives 1
The amount of the primary air is reduced, and even if the supply amount of the fuel gas G is small, the back phenomenon of the flame F due to the excess primary air P does not occur.

On the other hand, when the opening of the proportional valve 10 is large and the rotation speed of the blower fan 4 is high, that is, when the flow velocity of the combustion air is high, the secondary air S
When passing through a and a, a part of the flow separates at the edge, and a vortex V is remarkably generated. In the situation where the vortex V is generated, a contraction occurs in the flow, and the flow is obstructed by interference.
The passage resistance of the next air S is large. For this reason, the secondary air ratio decreases and the primary air ratio increases accordingly. Thereby, the amount of primary air is increased, and even if the supply amount of the fuel gas G is large, poor combustion such as incomplete combustion does not occur.

That is, the forced combustion device 6 is configured such that the passage shape of the secondary air S is such that the passage resistance is small when the flow velocity of the secondary air S is small, and the passage resistance is large when the flow velocity is large. It functions as an air ratio decreasing means, and increases the primary air ratio in reaction to the decrease in the secondary air ratio. This realizes a forced combustion device that can burn at an appropriate primary air ratio regardless of whether the supply amount of the fuel gas G is large or small.

This effect is shown in the graph of FIG. This graph shows the Reynolds number Re, which is a dimensionless number proportional to the flow velocity.
Is a graph showing the change of the flow coefficient C on the horizontal axis.
As shown by the curve y, the flow coefficient C in the forced combustion device 6 decreases as the Reynolds number increases, that is, the passage resistance increases. On the other hand, for comparison, the ventilation plate 18
The curve x showing the characteristic when one ventilation plate 17 is used except for the above is a substantially constant flow coefficient C regardless of the Reynolds number.
Which is remarkably different from the characteristics of the forced combustion device 6.

Various modifications can be made to the ventilation plates 17 and 18 as the secondary air ratio reducing means in the forced combustion device 6 of this embodiment. For example, vent holes 17a, 18a
Need not necessarily be provided at positions facing each other,
They may be provided at different positions. Also, as shown in FIG. 9, three ventilation plates 17, 18, and 19 are provided,
a, 18a and 19a may be formed.

Alternatively, as shown in FIG.
Vent plates 17A and 18A in which warpages 17b and 18b are formed at an edge portion of 18a may be used. This warp 17b, 1
When the ventilation plates 17A and 18A with 8b are used, the flow separation effect at the edge is large, and the change in passage resistance due to the flow velocity appears more strongly. As shown in FIG. 11 or 12, only one of the two ventilation plates may be warped. Alternatively, as shown in FIG. 13, by using thick ventilation plates 17B and 18B and forming wedge portions 17c and 18c at the edges of the ventilation holes, the flow separation effect can be increased.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. The forced-combustion apparatus 11 of the third embodiment shown in FIG. 14 generally includes a machine frame 50 provided with a gas burner 3, a blower fan 4, and a heat exchanger 5, and has a fixed secondary air ratio reducing means. In this respect, it is common to the forced combustion device 6 of the second embodiment. Therefore, in the following description, the same reference numerals are used for the common parts, and differences from the forced combustion device 6 will be mainly described. What is provided as a secondary air ratio reducing means in the forced combustion device 11 is a ventilation plate 22, in which a large number of ventilation holes 23 are formed, and a slope is formed immediately above each ventilation hole 23. Is provided. Then, as shown in FIG. 15, each current plate 24 has a shape like an axial fan as a whole due to its inclination.

Next, the action of changing the secondary air ratio in the forced combustion device 11 will be described. In the forced combustion device 11, similarly to the forced combustion device 6, the passage resistance of the secondary air S naturally changes according to the flow velocity of the secondary air S according to the passage shape of the secondary air S. That is, in the forced combustion device 11, since each straightening plate 24 is given an inclination like an axial fan, a rotation component is given to the secondary air S passing through the ventilation hole 23 as shown in FIG.

Therefore, when the opening of the proportional valve 10 is small and the rotation speed of the blower fan 4 is low, that is, when the flow velocity of the combustion air is small, the rotational component is small and the interference is small, so that the passage resistance of the secondary air S is reduced. small. For this reason, the secondary air ratio increases and the primary air ratio decreases accordingly. As a result, the amount of the primary air is reduced, and even if the supply amount of the fuel gas G is small, the back phenomenon of the flame F due to the excess of the primary air P does not occur.

On the other hand, when the opening of the proportional valve 10 is large and the rotation speed of the blower fan 4 is high, that is, when the flow velocity of the combustion air is large, the rotation component also becomes large, causing interference of the flow and the secondary air S. The passage resistance is significantly increased. For this reason, the secondary air ratio decreases and the primary air ratio increases accordingly. Thereby, the amount of primary air is increased, and even if the supply amount of the fuel gas G is large, poor combustion such as incomplete combustion does not occur.

That is, the forced combustion device 11 is connected to the forced combustion device 6
Similarly to the above, the passage shape of the secondary air S is set so that the passage resistance is small when the flow velocity of the secondary air S is small, and the passage resistance is large when the flow velocity is large. The primary air ratio is increased in reaction to the decrease in the secondary air ratio.
This realizes a forced combustion device that can burn at an appropriate primary air ratio regardless of whether the supply amount of the fuel gas G is large or small.

As described above in detail, in each forced combustion device according to each of the above-described embodiments, the blowing fan 4 is driven in accordance with the supply amount of the fuel gas G to the gas burner 3 to make the combustion air excessive or insufficient. And the primary air ratio is increased with an increase in the supply amount of the fuel gas G. Therefore, when the supply amount of the fuel gas G is small, the primary air ratio is decreased to cause an excess of the primary air P. When the back-up phenomenon of the flame is prevented and the supply amount of the fuel gas G is large, 1
An excellent forced combustion device has been realized in which the ratio of secondary air is increased to prevent poor combustion due to a shortage of primary air P.

In particular, in the forced combustion device 1 according to the reference example, the damper plate 1 partially covering the primary air port 3 b of the gas burner 3.
2, the controller 20 drives the damper motor 13 to change the effective opening area to increase or decrease the passage resistance of the primary air P. Therefore, when the supply amount of the fuel gas G is small, the effective opening area is reduced. To reduce the primary air ratio by decreasing the passage resistance of the primary air P, and to decrease the passage resistance of the primary air P by increasing the effective opening area when the supply amount of the fuel gas G is large. Accordingly, the primary air ratio can be increased, and a good combustion state can be obtained regardless of the supply amount of the fuel gas G.

Further, in the forced combustion device 2 according to the first embodiment, the passage resistance of the secondary air S is increased by the increase of the pressure T of the combustion air sent from the blower fan 4 by the ventilation plates 17 and 18 and the spring 21. The fuel gas G
When the supply amount of fuel gas G is small, the pressure T of the combustion air is also small, so that the passage resistance of the secondary air S is small and the secondary air ratio is large. Since the pressure T is also large correspondingly, the passage resistance of the secondary air S is large and the secondary air ratio is small. Therefore, the primary air ratio increases and decreases in the opposite direction to the secondary air ratio, and a good combustion state can be obtained regardless of the supply amount of the fuel gas G.

In the forced combustion device 6 according to the second embodiment, the ventilation plates 17 and 18 increase the flow velocity of the combustion air sent from the blower fan 4 and increase the passage resistance of the secondary air S. Therefore, when the supply amount of the fuel gas G is small, the flow velocity of the combustion air is also small, so that the passage resistance of the secondary air S is small and the secondary air ratio is large, while, when the supply amount of the fuel gas G is large, Since the flow velocity of the combustion air is also large correspondingly, the passage resistance of the secondary air S is large and the secondary air ratio is small. Therefore,
The primary air ratio increases and decreases in the opposite direction to the secondary air ratio, and a good combustion state is obtained regardless of the supply amount of the fuel gas G. The same effect can be obtained with the forced combustion device 11 according to the third embodiment.

It should be noted that the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the scope of the present invention.

[0057]

As described above, according to the present invention, as the gas input increases , the passage of the ventilation holes as the passage of the secondary air increases.
The characteristic that the road resistance increases increases the gas input
Is large, the secondary air ratio is reduced,
Increase air ratio to prevent primary air shortage and reduce gas
When the cut is small, increase the secondary air ratio and
Forced combustion with reduced primary air ratio to prevent excessive primary air
A baking device can be provided . Because of this,
Prevents excessive or insufficient primary air flow in the put range
Good combustion is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a forced combustion device according to a reference example.

FIG. 2 is a view showing a portion of a primary air port of a gas burner of the forced combustion device of FIG. 1;

FIG. 3 is a diagram showing a configuration of a forced combustion device according to the first embodiment.

FIG. 4 is a diagram showing a configuration of a ventilation plate portion of the forced combustion device of FIG. 3;

FIG. 5 is a diagram showing a configuration of a forced combustion device according to a second embodiment.

FIG. 6 is a diagram showing a flow of secondary air at the time of small input of the forced combustion device of FIG. 5;

FIG. 7 is a diagram showing a flow of secondary air at the time of large input of the forced combustion device of FIG. 5;

FIG. 8 is a graph illustrating a ventilation resistance characteristic of secondary air of the forced combustion device of FIG. 5;

9 is a diagram showing a modification of the configuration of the ventilation plate portion of the forced combustion device of FIG.

10 is a diagram showing a modification of the configuration of the ventilation plate portion of the forced combustion device of FIG.

11 is a diagram showing a modification of the configuration of the ventilation plate portion of the forced combustion device of FIG.

12 is a diagram showing a modification of the configuration of the ventilation plate portion of the forced combustion device of FIG.

13 is a diagram showing a modification of the configuration of the ventilation plate portion of the forced combustion device of FIG.

FIG. 14 is a diagram showing a configuration of a forced combustion device according to a third embodiment.

15 is a diagram showing a configuration of a ventilation plate portion of the forced combustion device of FIG.

FIG. 16 is a diagram showing a flow of secondary air in the forced combustion device of FIG.

[Explanation of symbols]

3 Gas burner 4 blower fan 10 Proportional valve 12 Damper plate 13 Damper motor 17, 18 Vent plate 20 Controller 21 Spring 22 Vent plate 24 Rectifier plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-240913 (JP, A) JP-A-64-67524 (JP, A) JP-A-3-38541 (JP, U) JP-A-61-38541 149630 (JP, U) Japanese Utility Model Showa 60-6957 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23N 3/00

Claims (5)

(57) [Claims] In a forced combustion apparatus having a burner, a gas amount adjusting means for adjusting a gas supply amount to the burner, and a blowing fan for supplying combustion air, the combustion air is controlled by controlling the blowing fan. Fan control means for maintaining the supply amount of gas within a predetermined allowable range with respect to the gas supply amount by the gas amount adjustment means, and combustion air supply by the blowing fan.
The secondary air ratio of the burner is reduced with an increase in the supply amount.
Secondary air reducing means, wherein the secondary air reducing means
Has a vent formed as a secondary air passage of the burner.
Two ventilation plates, of which the upstream ventilation plate is
At a predetermined distance from the side ventilation plate via an elastic member
Increase the supply of combustion air by the blower fan
When the space is reduced, the secondary space of the vent hole is reduced.
Forced combustion characterized by increasing air passage resistance
apparatus. 2. A forced combustion device having a burner, gas amount adjusting means for adjusting a gas supply amount to the burner, and a blower fan for supplying combustion air, the combustion air being controlled by controlling the blower fan. Fan control means for maintaining the supply amount of gas within a predetermined allowable range with respect to the gas supply amount by the gas amount adjustment means, and combustion air supply by the blowing fan.
The secondary air ratio of the burner is reduced with an increase in the supply amount.
Secondary air reducing means, wherein the secondary air reducing means
Has a vent formed as a secondary air passage of the burner.
A plurality of ventilation plates, and these ventilation plates
As the air supply for combustion increases due to the
They are juxtaposed at intervals that increase the resistance of the air passage.
A forced combustion device, characterized in that: 3. An air vent formed in said juxtaposed and adjacent ventilation plate.
Are provided at positions where they do not face each other.
3. The enforcement according to claim 1 or 2, wherein
Combustion equipment. 4. The ventilation hole of the ventilation plate has a secondary shape.
It is formed so that the upstream side of the air is narrow and the downstream side is wide
4. The method according to claim 1, wherein
Forced combustion equipment. 5. A burner and a gas supply amount to the burner.
Adjust gas volume to adjust Means and air supply for supplying combustion air
A forced combustion device having a fan;
Means for controlling the supply amount of combustion air by the gas amount adjusting means.
Within the specified tolerance for gas supply by
Fan control means; and air supply for combustion by the blower fan.
The secondary air ratio of the burner is reduced with an increase in the supply amount.
Secondary air reducing means, wherein the secondary air reducing means
Is formed with a plurality of ventilation holes serving as secondary air passages of the burner.
The ventilation plate is provided downstream of the openings of these ventilation holes.
Rectifier plate that gives a rotating component to the secondary air passing through the ventilation hole
The combustion by the blower fan
With the increase in the supply amount of air for use, the passage resistance of the
A forced combustion device characterized by increasing resistance.