JP2000002417A - Combustion air supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion air supplying device capable of surely decreasing or deadening combustion resonance noises by a simple device structure. SOLUTION: The combustion air supplying device comprises a fan case 1 having a rotary vane 2 with a plurality of vane parts 5 centrifugally blowing air toward its radius direction by rotation, a rotary shaft 3a interlockingly connected to the rotary vane 2, a suction port 7 that surrounds the rotary vane 2 and sucks air in the rotary shaft center direction of the rotary vane 2, and an exhaust port 8 exhausting air in an roughly tangential direction of the rotation peripheral direction of the rotary vane 2, and a drive mechanism 3 driving the rotary shaft 3a. In a high pressure region in an air channel that reaches the rotary vane 2 from the suction port 7, a shield object 9b shielding a part of the air channel is extendedly provided toward the inside of the fan case 1 from the suction port 7, and the shielding object 9b is position-alterably and fixably provided in the rotation peripheral direction of the rotary vane 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary blade having a plurality of blades for centrifugally blowing air in the radial direction by rotation, a rotary shaft interlocked to the rotary blade, and a rotary blade surrounding the rotary blade. And a fan case having an intake port for sucking air in the direction of the rotation axis of the rotary blade and an exhaust port for discharging air in a direction substantially tangential to the rotational direction of the rotary blade, and driving the rotary shaft. And a combustion air supply device having a driving mechanism.

[0002]

2. Description of the Related Art Such a combustion air supply device is used, for example, for supplying combustion air to a gas burner of a hot water supply device, and is used for discharging a burner box containing a gas burner and exhaust gas after combustion. When various factors such as the shape and volume of the exhaust box or the combustion characteristics of the burner satisfy the resonance condition, a resonance phenomenon of combustion noise may be generated to generate low frequency (for example, tens of Hz) combustion resonance sound. It has been known.

Conventionally, to solve such a resonance phenomenon, (1) a resonance box containing a diaphragm is communicated with a burner box containing a burner to reduce resonance noise by vibration of the diaphragm (for example, (2) To reduce resonance sound by a so-called active noise control in which a sound input from a microphone is output from a speaker in an opposite phase (for example, the official technique number 91-21133). (3) A method of reducing combustion noise by releasing the pressure generated by combustion to the outside by means of an escape means such as a pressure equalizing pipe (for example, Japanese Patent Application Laid-Open No. 63-176916) (4) A vibrating piece that resonates at the frequency generated by combustion of the burner is mounted near the intake port of the fan case, and the vibrating piece absorbs vibration energy and A device that reduces a sound (for example, see Japanese Utility Model Laid-Open No. 5-25141) is known.

[0004]

SUMMARY OF THE INVENTION
In the method (1), the resonance box requires a certain volume,
There is a drawback that the device becomes large, and the method (2) requires an input / output device such as a microphone and a speaker and a control unit,
There are drawbacks such as a complicated and expensive device. Also,
In the method (3), a means for releasing the pressure generated between the heat exchanger and the exhaust section is provided. In the method (4), only the resonator element that resonates with the vibration frequency during combustion is located somewhere between the intake side opening and the exhaust side opening of the combustion device. Therefore, it is quite difficult to prevent various kinds of combustion resonance noise only by the vibrating reed, and there is a disadvantage that the applicable range is extremely limited. As described above, the conventionally known methods (1) to (4) are not sufficiently established in terms of technology, or the structure is complicated and expensive. It was hard to find a satisfactory method.

The present invention focuses on such disadvantages of the prior art, and has as its object to provide a combustion air supply device capable of reliably reducing or eliminating combustion resonance with a relatively simple device configuration. To provide.

[0006]

According to the first aspect of the present invention, in order to achieve the above object, in the high-pressure region of the air flow path from the intake port of the fan case to the rotating blades, Since the shielding object that shields a part of the flow path extends from the intake port toward the inside of the fan case, the flow of the air taken in from the intake port is increased by the shielding object in the high-pressure region. Partially interrupted, a turbulence occurs, which interacts immediately with the rotational movement of the rotating blades rotating immediately downstream. And although the detailed reason is not clear, as is clear from the results of the examples described later, the combustion resonance sound of the burner is reduced by the interaction in the high pressure region in a state where there is almost no decrease in the blowing amount. It is considered that the resonance is suppressed, and as a result, the combustion resonance can be reliably reduced or eliminated with a relatively simple device configuration. And, there remains a problem that the mounting position of the shielding object is not constant due to a manufacturing error, even if the device has the same specification.
Regarding that point, the position of the shielding object can be changed in the high pressure region while the device is actually operating by configuring the shielding object so that the position of the shielding object can be changed and fixed in the rotational circumferential direction of the rotating blades. By determining the optimum position based on the operation of and fixing the shielding object, the combustion resonance can be reliably reduced or eliminated.

According to the second aspect of the present invention, the shielding object is provided so as to be capable of changing its position along an arc centered on the rotation axis of the rotating blade so as to be freely fixed. When determining the optimal position by changing the mounting position of the shielding object while making it, the position of the shielding object can be freely changed within the high pressure area without the shielding object interfering with the rotating blade In addition, it is possible to easily determine the optimum position of the shielding object, perform a position change fixing operation, and the like.

According to the third aspect of the present invention, since the shielding object is formed of a flat plate, it can be manufactured with a very simple configuration and at a low cost. Since it is attached to the fan case via the position change fixing means, the shielding object can be fixed with a simple configuration using the necessary fan case, and
By attaching to the fan case surrounding the rotating blade, the position of the shielding object with respect to the rotating blade can be easily determined, and the effect of reducing or eliminating the combustion resonance sound by the shielding object can be obtained more reliably.

According to the fourth aspect of the present invention, the rotary blade is composed of a plurality of blades and a rotary plate fixedly holding the plurality of blades. When viewed from the back, the rotating shaft is fixed to the rotating plate and the rotating shaft is fixed to the rotating plate. Since they are integrally connected, in the high pressure area of the air flow path from the intake port of the fan case to the rotating blades,
In addition to the shielding object, the flow of air on the far side of the fan case is also partially interrupted by the parallel plate portion continuously provided at the end thereof, causing turbulence.
In addition, the turbulence interacts with the rotational movement of the rotary blade immediately afterward, so that combustion resonance can be more effectively reduced or eliminated.

According to the fifth aspect of the present invention, the position change fixing means is formed by an arc-shaped long hole provided in one of the shielding object and the fan case, and a fixing tool penetrating the long hole. With this configuration, the position change fixing means can be formed with a very simple configuration, and the position change of the shielding object can be extremely easily performed using the arc-shaped long hole with the fixing tool loosened. Fixing work can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a combustion air supply device according to the present invention will be described with reference to the drawings. This combustion air supply device is used, for example, to supply combustion air to a burner of a hot water supply device.
As shown in FIG. 2, the sirocco fan F is of a centrifugal blow type. The sirocco fan F as a combustion air supply device includes a fan case 1 and a rotary blade 2 housed and held in the fan case 1, and the rotary blade 2 is driven by an electric motor 3 as a drive mechanism. The case 1 is configured to be driven to rotate in a direction indicated by an arrow in FIG.

The rotating blade 2 includes a disk-shaped rotating plate 4,
A plurality of plate-like blade portions 5 fixedly held around the rotary plate 4, and ends of the respective blade portions 5 on the opposite side to the rotary plate 4 are also connected by an annular ring plate 6. The rotating plate 4 is fixedly held on the rotating shaft 3a of the electric motor 3. The fan case 1 is provided with a bell mouth-shaped intake port 7 for air suction on the front surface thereof, and gradually surrounds the rotating blade 2 toward the downstream side in the rotation direction of the rotating blade 2 while the fan case 1 surrounds the rotating blade 2. A rectangular exhaust port 8 which spreads and discharges air after pressurization is provided at an upper end thereof.

With respect to the fan case 1, the rotating plate 4 is positioned on the back side of the fan case 1 when viewed from the intake port 7, and the electric motor 3 is fixed to the rear surface of the fan case 1, whereby The blades 2 are housed and held in the fan case 1 in a state where the rotation axis 3a, which is the rotation axis thereof, substantially coincides with the center of the intake port 7 and the ring plate 6 of the rotary blades 2 faces the intake port 7. It is configured to be.
Then, the rotary blades 2 are driven to rotate by the electric motor 3, so that air is sucked from the intake port 7 in the direction of the rotation axis of the rotary blades 2 and the sucked air is centrifugally blown by the rotary blades 2 in the radial direction. The air is pressurized while being discharged, and the pressurized air is discharged from an exhaust port 8 located substantially tangentially in the rotational circumferential direction of the rotary blade 2.

The air sucked from the intake port 7 is discharged from the exhaust port 8 in this manner.
In the air flow path from the intake port 7 to the rotary blade 2 and in the high pressure region, a shielding member 9 for shielding a part of the air flow path from the air flow path to the exhaust port 8. Is located. The shielding member 9 is integrally bent by a metal flat plate, and has a mounting portion 9a that contacts along the front surface of the fan case 1 and a shielding portion that is bent substantially at right angles to the mounting portion 9a. A flat plate portion 9b as an object, substantially perpendicular to the flat plate portion 9b, and
And a parallel plate portion 9c that is bent to the opposite side.

The mounting portion 9a is formed with an arc-shaped long hole 10 centered on the rotation axis of the rotary blade 2, and a screw 11a as a fixture is penetrated into the long hole 10 to form a fan case. By screwing into the female screw hole 11b engraved on the front surface of the fan case 1, the shielding member 9 can be attached to the fan case 1. With the shielding member 9 attached, the flat plate portion 9b of the shielding member 9 It extends toward the inside of the case 1 and is located in the air flow path from the intake port 7 to the blade part 5 of the rotary blade 2 and is located in the high-pressure region of the air flow path. Is configured. That is, the air sucked from the intake port 7 is gradually pressurized with the rotation of the rotary blades 2 and is exhausted from the exhaust port 8. More specifically, as shown by a dashed line in FIG. 5, it is configured to be located in a region near the exhaust port 8.

When the shielding member 9 is attached to the fan case 1, the parallel plate portion 9c of the shielding member 9 is positioned substantially parallel to the rotary plate 4 adjacent to the rotary plate 4 of the rotary blade 2. Further, the screw 11a is loosened, and the position of the shielding member 9 is changed along an arc centered on the rotation axis of the rotary blade 2 using the arc-shaped long hole 10 of the mounting portion 9a, and again The position of the shielding member 9 can be changed by tightening and fixing the screw 11a. That is, the long hole 10 and the screw 11 of the mounting portion 9a
a and the female screw hole 11b of the fan case 1 constitute a position change fixing means.
The mounting positions of the shielding member 9, particularly the mounting positions of the flat plate portion 9b and the parallel plate portion 9c, are determined by 0, 11a, and 11b.
It is configured so that the position of the rotary blade 2 can be changed and fixed in the rotational circumferential direction within the high-pressure region.

In the sirocco fan F having such a shielding member 9, the intake port 7 is
A part of the air which is sucked from and reaches the blade portion 5 of the rotary blade 2 through the inside of the high-pressure region is formed by the flat plate portion 9 b of the shielding member 9.
And the parallel plate portion 9c interrupts the flow and causes turbulence, and the turbulence immediately interacts with the rotational movement of the blade portion 5 rotating immediately downstream. It is considered that this interaction can suppress the combustion resonance of the burner as shown in the results of the examples described later.

The sirocco fan F is used, for example, for supplying combustion air to a burner of a hot water supply apparatus. The burner of the hot water supply apparatus has a schematic configuration shown in FIG. As shown in the actual configuration, a plurality of rich burners 12 are arranged in the burner case 13 so that a plurality of light burners B are formed between the rich burners 12 in a light-and-light combustion burner B. A plurality of dark burners 12 are divided into two blocks, and the divided dark burners 1 are divided into two blocks.
2 and the light burner 14, the original gas supply path 1
5, three gas supply paths 15a, 15b, 1
5c are configured to supply fuel gas, respectively,
The original gas supply path 15 has an original gas solenoid valve 16 and a gas proportional valve 17, and each of the gas supply paths 15 a, 15 b, 15 c has
Switching electromagnetic valves 18a, 18b, 18c are provided respectively.

The lean burn burner B is also provided with an igniter 19 for ignition. At the time of high capacity combustion, all the switching solenoid valves 18a, 18b and 18c are opened, and all the rich burners 12 are opened. And the light burner 14 are burned, and when the combustion is in progress, the two switching solenoid valves 18a,
The valve 18c is opened, and only the rich burners 12 of both blocks, in other words, all the rich burners 12 are burned. Further, during combustion with a small capacity, only one switching electromagnetic valve 18a is opened, and only the rich burner 12 of one block is burned. In any combustion state, the opening degree of the gas proportional valve 17 is increased. The adjustment controls the combustion amount of the burner B.

The burner B is accommodated in the burner box 20, and the heat exchanger 21 located above the burner box 20 is heated by the combustion of the burner B, and passes through the heat exchanger 21. The flowing water is heated and supplied with hot water, and the exhaust gas after combustion is discharged to the outside through the exhaust port 23 of the exhaust box 22. The exhaust port 8 of the sirocco fan F described above is connected to an opening 24 opened at the bottom of the burner box 20, and the combustion air from the sirocco fan F is supplied to the rich burner 12.
The fuel gas is mainly supplied by the ejector action accompanying the blowing of the fuel gas from the gas supply passages 15a and 15c, and is supplied to the light burner 14 mainly in a form mixed with the fuel gas in the burner case 13; When combustion is performed, the combustion air is supplied from the light burner 14.

In the hot water supply apparatus having such a configuration, the sirocco fan F, the burner B, the burner box 2
0, even if all members such as the exhaust box 22 have the same specifications, when actually operated, the position of the shielding member 9 suitable for suppressing the combustion resonance caused by the combustion of the burner B is not necessarily. They do not match and vary slightly depending on the individual device. In such a situation, while actually operating the apparatus, the mounting position of the shielding member 9 is changed and adjusted by using the arc-shaped long hole 10 provided in the mounting portion 9a of the shielding member 9, thereby changing each position. The optimum mounting position for the apparatus can be easily and quickly determined, and then the screw 11a is tightened and fixed, so that the shielding member 9 can be easily mounted.

[Another Embodiment] Another embodiment will be described below. (1) In the above embodiment, the flat plate portion 9b of the shielding member 9 is a flat plate. However, as shown in FIG. 6, a flat plate portion as a shielding object is formed as a curved plate almost along the inside of the rotary blade 2. 9d
In this case, the gap between the curved plate 9d and the rotary blade 2 can be reduced, and a part of the air flow path can be more reliably shielded.
The intake port 7 can be hardly blocked, and an increase in pressure loss can be prevented.

(2) In the above embodiment, the shielding object is the flat plate 9b or the curved plate 9d, and the side end portion thereof is not particularly devised. However, as shown in FIG. An internal bending piece 9e for windbreak can be extended from the side end of the rotating blade 9b toward the rotation upstream side of the rotating blade 2, and in this case, in addition to suppressing the combustion resonance noise, the rotating blade 2 , And another inner curved piece 9f can be extended toward the downstream side of the rotation of the rotary blade 2 as shown by a virtual line.

(3) In the above embodiment, an example is shown in which the arc-shaped long hole 10 is formed in the mounting portion 9a of the shielding member 9. However, the hole 10 is not necessarily required to be arc-shaped. As shown in the figure, the shielding member 9 can be configured to be freely changeable and fixed in the rotation circumferential direction of the rotary blade 2 by using a linear elongated hole 10a extending substantially in the vertical direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for clarifying the above-mentioned functions and effects of the present invention will be described below. Example 1 A sirocco fan F as shown in FIG. 1 and FIG. 2 was manufactured with the following dimensions, and a gas supply amount (Ip ) And the air ratio (Mo) were actually changed, and the suppression effect of combustion resonance was examined. Diameter of the intake port 7 of the fan case 1: 77 mm Depth from the intake port 7 to the rotating plate 4: 36 mm Diameter of the rotation locus inside the blade 5: 77 mm Width of the flat portion 9 b in the vertical direction: 52 mm of the flat portion 9 b Length in the depth direction: 32 mm Width of the parallel plate portion 9 c: 13 mm The dimensions of each part in the burner B are as follows. Burner case 13: width 200 mm x depth 150 mm
X height 160mm heat exchanger 21: width 200mm x depth 150mm
X height 180mm exhaust box 22: width 200mm x depth 150mm
× height 50 mm FIG. 8 shows the results of three separate runs. Each data shows the case where the air supply ratio (Mo) is gradually reduced while the gas supply amount (Ip) is constant, and the combustion resonance sound starts to be generated. The air ratio (Mo) is shown. That is, when the air supply ratio (Mo) falls below a certain value while the gas supply amount (Ip) is constant in the above-described rich-burn combustion burner B, combustion resonance is generated, but the suppression effect is reduced by the reduction effect of the air ratio (Mo). It has been examined. As shown by these results, the air ratio was reduced by about 0.2 for all three times by using the flat plate portion 9b as the shielding object.
It can be seen that the combustion resonance is suppressed accordingly. Note that, in the above-described light-and-dark combustion burner B, the air ratio is 1.6 to 2.2.
Since it is ideal to control the combustion in the range of 0, it is very significant not to generate combustion resonance in this range.

Example 2 An experiment similar to that of Example 1 was performed, except that the shapes of the flat plate portion 9b and the parallel plate portion 9c were changed to the following. FIG. 9 shows the result. Assuming that the width of the flat plate portion 9b in the vertical direction is W, the depth length of the flat plate portion 9b is H, and the width of the parallel plate portion 9c is L, A: W = 52 mm, H = 32 mm, L = 10 mm B: W = 48 mm, H = 32 mm, L = 10 mm C: W = 52 mm, H = 29 mm, L = 10 mm. A 'has the same size as A, and the mounting portion 9a has
Vent 9g (17 × 36mm) as shown by a virtual line inside
A ″ is obtained by firmly fixing A to the fan case 1. As the result of FIG. 9 shows,
In the first embodiment, even if the shapes of the flat plate portion 9b and the parallel plate portion 9c are changed.
It was found that the same effect as described above was obtained. The fact that the degree of the effect does not change even when the mounting strength of the flat plate portion 9b and the parallel plate portion 9c is changed indicates that the effect of the present invention cannot be obtained due to resonance of the shielding object. This is supported by the fact that the same effect is obtained even when the flat plate portion 9b and the parallel plate portion 9c are formed three-dimensionally and the weight is increased.

Example 3 An experiment similar to that of Example 1 was performed, except that the shapes of the flat plate portion 9b and the parallel plate portion 9c were changed to the following and firmly fixed. The result is shown in FIG. In the shielding member 9 shown in FIG. 7, the vertical width of the flat plate portion 9b is W, the depth length of the flat plate portion 9b is H, the width of the parallel plate portion 9c is L, and the radii of the inner bent pieces 9e and 9f are R. Then, D-1: W = 52 mm, H = 32 mm, L = 10 mm,
R = 10 mm (Vent 9g (17 × 20
mm)) D-2: W = 52 mm, H = 32 mm, L = 10 mm,
R = 10 mm (without vent 9g in the mounting portion 9a) D-3: W = 52 mm, H = 32 mm, L = 10 mm,
R = 10 mm (the mounting portion 9a has no vent 9g). D-3 is arranged so as to be almost in contact with the rotation trajectory inside the blade portion 5 (the gap is 2 mm), and the others are provided with a gap of 4 mm.
mm. As shown in the results of FIG.
It was found that the same effect as in Example 1 was obtained even if the shape of b and the parallel plate portion 9c were changed.

Embodiment 4 A sirocco fan F as shown in FIGS. 1 and 2 and a burn-in-and-burn burner B as shown in FIGS. The actual combustion was performed while changing the rotation speed of (Ip) and the sirocco fan F, and the effect of suppressing the combustion resonance was examined. Diameter of the intake port 7 of the fan case 1: 65 mm Depth from the intake port 7 to the rotary plate 4: 25 mm Diameter of the rotation locus inside the blade 5: 80 mm Width of the flat portion 9 b in the vertical direction: 40 mm Length in the depth direction: 24.6 mm Width of the parallel plate portion 9 c: 9.8 mm The dimensions of the burner box 20 including the heat exchanger 21 are as follows. Burner box 20: 185mm width x
FIG. 11 shows the results of the measurement performed a plurality of times. As is clear from the results, the use of the flat plate portion 9b or the parallel plate portion 9c as the shielding object makes it possible to reduce the generation region of the combustion resonance sound. It can be seen that there is a large deviation from the fan control line L of the light and shade combustion burner B, and it is very significant that no combustion resonance is generated on the fan control line L.

Example 5 Using the same sirocco fan F and the thick and light combustion burner B as in Example 4, the actual air flow was examined while changing the rotation speed of the sirocco fan F. The gas supply amount (Ip) is
It was constant at about 30,000 Kcal / hour. The result is shown in FIG. 12, and it is clear from the result that the actual airflow does not change much when the shielding member 9 is attached and when it is not attached.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of a combustion air supply device.

FIG. 2 is a front view of a combustion air supply device.

FIG. 3 is a schematic configuration diagram of a burner using a combustion air supply device.

FIG. 4 is an exploded perspective view of a burner using a combustion air supply device.

FIG. 5 is a schematic diagram showing a high pressure region of the combustion air supply device.

FIG. 6 is a perspective view showing a shielding member of another embodiment.

FIG. 7 is a perspective view showing a shielding member of another embodiment.

FIG. 8 is a diagram showing the results of Example 1.

FIG. 9 is a diagram showing the results of Example 2.

FIG. 10 shows the results of Example 3.

FIG. 11 shows the results of Example 4.

FIG. 12 shows the results of Example 5.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fan case 2 Rotating blade 3 Drive mechanism 3a Rotating shaft 4 Rotating plate 5 Blade 7 Inlet 8 Exhaust 9b, 9d Shielding object 9c Parallel plate 10 Arc-shaped long hole 11a constituting position changing fixing means 11a position changing and fixing Connecting means constituting means F combustion air supply device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikatsu Ishikawa 1-152 Oka, Minami-ku, Osaka-shi, Osaka F-term in Harman Co., Ltd. 3H034 AA02 AA13 BB02 BB06 CC03 DD05 EE06 3K023 AA02

Claims (5)

[Claims] 1. A rotating blade having a plurality of blades for centrifugally blowing air in a radial direction by rotation, a rotating shaft interlockingly connected to the rotating blade, and surrounding the rotating blade and the rotating blade. A fan case having an intake port for sucking air in the direction of the rotation axis and an exhaust port for discharging air in a direction substantially tangential to the rotation circumferential direction of the rotating blades; and a drive mechanism for driving the rotation shaft. A high-pressure region of an air flow path from the intake port to the rotary blade, wherein a shielding object that shields a part of the air flow path from the intake port to the fan. A combustion air supply device that extends toward the inside of a case and is provided such that the position of the shielding object can be freely changed and fixed in the rotational circumferential direction of the rotary blade. 2. The combustion air supply device according to claim 1, wherein the shielding object is provided so that its position can be changed and fixed along an arc centered on the rotation axis of the rotary blade. 3. The combustion air supply device according to claim 1, wherein the shielding object is formed of a flat plate, and the shielding object is attached to the fan case via position change fixing means. 4. The rotating blade includes a plurality of blades and a rotating plate fixedly holding the plurality of blades, and
The rotating plate is located on the back side of the fan case when viewed from the intake port, and the rotating shaft is fixed to the rotating plate, and the end of the shielding object formed of the flat plate on the back side of the fan case. 4. The combustion air supply device according to claim 3, wherein a parallel plate portion substantially parallel to the rotary plate is integrally connected. 5. The position changing and fixing means comprises an arc-shaped long hole provided in one of the shielding object and the fan case, and a fixing tool penetrating the long hole. Or the combustion air supply device according to 4.