JPH0512613B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a forced air combustion apparatus in which combustion air is supplied by a blower, and is particularly effective in those that perform high-load combustion.

[Conventional technology]

In recent years, there has been a demand for smaller combustion devices, especially water heaters. In addition, in forced-air combustion devices that supply combustion air into the casing using a blower, noise is likely to be generated due to high-load combustion. The applicant has already proposed a combustion device in which noise is reduced by matching the natural frequency of the supply section in which the

[Problem to be solved by the invention]

However, when combustion generates noise, such as wind noise from blowing air or vibration from flame propagation, small combustion devices have limited combustion chamber volume, so these noises can cause problems. 800Hz
Air column vibrations of 3200Hz are likely to occur. As a result, there is a problem in that the combustor resonates and generates large noise.

An object of the present invention is to provide a forced air combustion device that can reduce noise generation, especially in a small combustion device.

[Means to solve the problem]

In the forced air combustion device of the present invention, in the first aspect of the invention, in the forced air combustion device, a burner having a flame port whose ejection direction is parallel to the casing is arranged, and combustion air is supplied by a blower. Within, the length of the opposite surface is 800Hz
Regarding the plane corresponding to the half wavelength of sound from 3200Hz,
The technical means is to make the surfaces non-parallel to the opposing surfaces.

In the second invention, a burner plate having a flame port whose ejection direction is parallel is arranged in a casing having an air supply port and an exhaust port to form a combustion chamber and a mixing chamber, and a blower casing equipped with an air blower is provided. In the forced air combustion device connected to the air supply port and supplying combustion air to the mixing chamber by the blower, the length of the opposing surface within the casing forming the mixing chamber is 800 Hz. The technical means is to make the surface corresponding to a half wavelength of sound from 3200 Hz to a non-parallel surface with respect to the opposing surface.

In the third invention, a combustion chamber is formed by arranging a burner having a flame port whose ejection direction is parallel to the casing having an air supply port and an exhaust port, and a forced-air combustion type equipped with a blower for supplying combustion air. In the device,
In the casing forming the combustion chamber, a surface whose length with the opposing surface corresponds to a half wavelength of sound from 800 Hz to 3200 Hz is made non-parallel to the opposing surface. Use technical means.

In the fourth invention, a burner plate having a flame port whose ejection direction is parallel is disposed inside the casing to form a combustion chamber and a mixing chamber, and a blower casing provided with an air blower is attached to the casing forming the mixing chamber. In a forced-air combustion device, the burner plate is connected perpendicularly to the surface facing the burner plate, and the blower supplies combustion air to the mixing chamber. The technical means is that it is placed on a non-parallel plane.

[Action and effect of the invention]

In the first invention, the surfaces whose length corresponds to the half wavelength of sound from 800Hz to 3200Hz, which is likely to be generated as noise during combustion, are non-parallel to each other, so vibrations occur within the casing. Since there are no repeated reflections and air column vibrations are less likely to occur, there is no resonance and no noise. In the second invention, the length of the mixing chamber between the opposing surfaces ranges from 800Hz to 3200Hz, which is likely to generate noise during combustion.
Since the planes corresponding to half the wavelength of sound are non-parallel to each other, the vibrations are not repeatedly reflected within the casing, and air column vibrations are less likely to occur, so they resonate in the mixing chamber. There will be no noise.

In the third invention, the length of the combustion chamber between the opposing surfaces is 800 mm, which tends to generate noise during combustion.
The surfaces corresponding to the half wavelength of sound from Hz to 3200Hz are non-parallel to each other, so vibrations are not repeatedly reflected within the casing.
Since air column vibration is less likely to occur, it does not resonate within the combustion chamber and cause noise.

In the fourth invention, since the burner plate has a non-parallel surface with the surface facing the burner plate of the casing forming the mixing chamber, the vibrations generated in the mixing chamber are caused by the vibration between the burner plate and the casing on the mixing chamber side. Since there are no repeated reflections between the two, there is no resonance and noise.

〔Example〕

Next, a forced air combustion apparatus of the present invention will be explained based on an embodiment shown in the drawings.

FIG. 1 shows a gas water heater 1 as a first embodiment of the present invention.

This gas water heater 1 includes a combustion section 10, a supply section 2
0, a water pipe 30, a fuel pipe 40, and a control device 50, and the entire system is housed in a water heater case (not shown).

In the combustion section 10 , a flat burner plate 12 having a large number of flame ports is arranged at the opening at the lower end of the combustion case 11 , and an exhaust pan 13 is provided at the opening at the upper end of the combustion case 11 .
A combustion chamber 14 is formed by the exhaust pan 13, and an exhaust passage 15 is formed by the exhaust pan 13.

The exhaust pan 13 is provided with an exhaust port 16 to discharge the combustion gas passing through the exhaust path 15 to the outside. Further, as shown in FIG. 2, the exhaust pan 13 has an inclined surface 13a formed of glass wool 13b at a portion facing the burner plate 12. This is because, in this embodiment, the length between the exhaust pan 13 and the burner plate 12 is, for example, 22.0 cm, which corresponds to a half wavelength of sound from 800 to 3200 Hz, which is the frequency at which air column vibration is likely to occur during combustion. Also, since the surface of the burner plate 12 is a flat surface that reflects air vibrations in the same direction, in order to prevent repeated reflections, the direction of reflection is changed from the direction of reflection of the burner plate 12, and the burner is placed in the exhaust pan 13. The surface parallel to the surface of the plate 12 is eliminated. This prevents resonance between the exhaust pan 13 and the burner plate 12 during combustion. Here, the inclined surface 13a is formed by fixing several layers of glass wool 13b with an inorganic binder.

A heat exchanger 31 connected to a water pipe 30 is provided in the upper part of the combustion case 11, and two sparkers 17 for ignition are provided near the burner plate 12 in the combustion case 11, and two sparkers 17 are provided for detecting ignition. A flame rod 18 for detecting the combustion temperature and a thermocouple 19 for detecting the combustion temperature are provided.

The supply unit 20 accommodates a mixing case 21 provided at the lower end of the combustion case 11 and a blower 22 that drives an impeller by a motor, and is provided in communication with an inlet 23 at the lower end of the mixing case 21. It consists of a ventilation case 24.

In the mixing case 21, the walls 21a and 21b in the left-right direction in FIG. 1 are inclined so that the distance on the combustion case 11 side becomes wider. In this example, this corresponds to mixed case 2.
The horizontal length of 1 is the burner plate 1 described above.
Similar to the relationship between 2 and the exhaust pan 13, this is for example 27.0 cm, which corresponds to a half wavelength of the frequency at which air column vibration is likely to occur at room temperature, so this is to prevent repeated reflections within the mixing case 21. . Here, the inclination of the wall portion 21a is made smaller than the inclination of the wall portion 21b, and differences are provided in the degree of inclination. As a result, compared to the case where there is no difference in the degree of slope,
By increasing the area of the rectifying plate 25 provided between the inlet 23 in the mixing case 21 and the burner plate 12, the load on the blower 22 can be reduced, so the rotation speed of the blower 22 can be lowered. It is possible to achieve low noise. Note that a plurality of holes are formed in the current plate 25 to equalize and supply air.

An air supply duct 26 is provided at the suction port 24b of the ventilation case 24, and the air supply port 26 of the air supply duct 26
A is provided with a nozzle 41 that spouts fuel gas supplied through a fuel pipe 40.

The fuel pipe 40 is equipped with a main solenoid valve 42 that controls the supply of fuel gas, a main solenoid valve 43, and a governor proportional valve 44 that adjusts the amount of fuel supply. Proportional valve 44
A solenoid valve 47 whose upstream and downstream sides are communicated by a bypass pipe 46 equipped with an orifice 45 is downstream of the solenoid valve 47 .
is provided.

On the other hand, a water flow sensor 32 for detecting the amount of water flowing into the heat exchanger 31 and an inflow water temperature thermistor 33 for detecting the temperature of the water flowing out from the heat exchanger 31 are installed in the water pipe 30 upstream of the heat exchanger 31. A hot water temperature thermistor 34 for detecting the temperature of the hot water is provided downstream of the heat exchanger 31, respectively.

In this embodiment, the length of the combustion case 11 forming the combustion chamber 14 in the left-right direction is about 27 cm, but the temperature inside the combustion chamber 14 is high during combustion and the frequency is such that air column vibrations are likely to occur. 800~3200
It does not correspond to a half wavelength of Hz sound, and in the left and right direction,
Since the flame has a sound absorption effect, there is no need to make it non-parallel to prevent noise.

The operation of the gas water heater 1 having the above configuration is controlled by the control device 50, and operates as follows.

When the user operates the faucet, water flows into the heat exchanger 31, and when this is detected by the water flow sensor 32, the blower 22 rotates at a predetermined rotation speed.
When this is detected, ignition control is started in a predetermined sequence, spark discharge is performed by the sparker 17, and the main solenoid valve 42, main solenoid valve 43, and solenoid 47 are opened, and the governor proportional valve 44 is opened. Apply current for slow ignition.

Then, air is sucked into the air supply duct 26 through the air supply port 26a, and further into the ventilation case 24 through the suction port 24b.

On the other hand, the fuel gas supplied from the fuel pipe 40 is
It passes through the main solenoid valve 42 and the main solenoid valve 43, the supply amount is adjusted by the governor proportional valve 44, and then the solenoid valve 47
The air passes through the nozzle 41 and is ejected into the air supply duct 26, mixes with air, and is sucked into the air blowing case 24, where it becomes an air-fuel mixture.

The air-fuel mixture in the blower case 24 is supplied to the mixing chamber 20a through the blower outlet 24a and the inlet 23, and after the pressure is equalized with respect to the burner plate 12 by the baffle plate 25, it flows into the combustion chamber 14. and is ignited by the activated sparker 17.

Ignition is detected by flame rod 18,
After a certain period of time has passed until the flame stabilizes, the blower 22 and the governor proportional valve 44 are controlled based on the set temperature by the controller 51 operated by the user and signals from each sensor and thermistor, and the combustion starts. will continue.

During combustion, some operating noise of the blower 22 and vibration noise due to flame propagation occur, but the walls 21a and 21b of the mixing case 21 forming the mixing chamber 20a,
Since the burner plate 12 and the exhaust pan 13 are non-parallel to each other, the length between them is at a frequency where air column vibration is likely to occur.
Even if it corresponds to a half wavelength of sound between 800 and 3200Hz, it will not resonate. Therefore, the noise is small.

FIGS. 3 and 4 respectively show a second embodiment and a third embodiment, which are modified versions of the mixed case of the first embodiment.

In the second embodiment shown in FIG. 3, in the mixing case 27, not only the wall portions 27a and 27b in the left and right directions shown in the figure are made non-parallel to each other, but also the bottom surface 27c provided at the inlet 23 is made relative to the burner plate 12. The surfaces are non-parallel.

In the third embodiment shown in FIG. 4, in the mixing case 28, wall portions 28a and 28b are provided with irregularities, respectively. In this case, if the unevenness is shallow, it will not be very effective in preventing the occurrence of air column vibration, so it is preferable to provide the uneven surface as deep as possible.

A fourth embodiment of the present invention is shown in FIGS. 5 and 6. In order to simplify the explanation, the same numbers are given to the same parts and the same functional parts as in the first embodiment.

In this embodiment, the burner plate 12a has a flat, approximately V-shaped cross section so that the surface is non-parallel to the flat surface 13c at the upper end of the exhaust pan 13, and the burner plate 12a has a flat, approximately V-shaped cross section. This prevents repeated reflections.

Further, in this embodiment, a damper 29 is provided in the air supply duct 26, as shown in FIG. 6, in order to make it difficult to generate noise even when the combustion amount changes. The damper 29 is swingably supported by a shaft 29a, and changes the opening degree of the air supply port 26a according to the amount of air sucked in by the blower 22. Further, the fuel gas is dispersed and ejected from a large number of ejection ports 48a and 49a arranged in two nozzle pipes 48 and 49, which are branched from the fuel pipe 40.

In addition, in FIG. 5, 35 is a water flow control valve for regulating the amount of inflow water, 36 is a heating water temperature thermistor that detects the temperature of the hot water that has passed through the heat exchanger 31, and 37 is a water flow control valve that does not allow water to pass through the heat exchanger 31. 38 is a heat exchanger 31
This is a bypass amount control valve that adjusts the ratio between the amount of water flowing out from the bypass pipe 37 and the amount of water flowing out from the bypass pipe 37.

In this embodiment, even if the length between the burner plate 12a and the exhaust pan 13 corresponds to a half wavelength of sound from 800 to 3200 Hz, which is the frequency at which air column vibration is likely to occur, resonance cannot occur. do not have. Further, when the combustion amount changes, the damper 29 changes according to the operating state of the blower 22, and the mixing chamber 2
Since the natural frequency of the supply side consisting of the air blowing case 24 and the air supply duct 26 can be made to match the natural frequency of the combustion chamber 14 side, no noise is generated.

FIG. 7, FIG. 8, and FIG. 9 show a fifth embodiment, a sixth embodiment, and a seventh embodiment of the present invention, respectively. In the fourth embodiment, the burner plate is a simple V
However, if the surface is not parallel to the exhaust pan or the mixing case, multiple V-shapes or convex shapes can be used, as shown in Figures 7, 8, and 9, respectively. Even if the surface is a curved surface or a simple inclined surface, generation of resonance can be similarly prevented.

FIG. 10 shows an eighth embodiment. In the gas water heater 1 of the eighth embodiment, the combustion chamber 1 in the combustion case 11
A heat exchanger 31 is provided only above the 4, a slit burner 12b for Bunsen combustion is provided below, and a nozzle pipe 48 is connected to each slit burner 12b.
Fuel gas is ejected from the ejection port 48a. In this embodiment, the wall surface 1 in the left and right direction of the combustion case 11 is
The distance between 1a and 11b is formed to be inclined so as to gradually widen upward. By this,
Even if the distance in the horizontal direction corresponds to a half wavelength of sound from 800 to 3200Hz, which is the frequency at which air column vibrations are likely to occur during combustion, reflection in the horizontal direction is prevented, resonance does not occur, and noise is eliminated. be able to.

Here, the wall surface of the combustion case is formed to gradually widen, but it may be formed to gradually narrow on the contrary, or only one side may be inclined.

In the above embodiments, a gas water heater has been described, but resonance noise can be prevented by using a similar configuration in any combustion equipment in which a burner is provided in a casing.

Although the present invention is aimed at reducing noise, the length of the opposing surface inside the combustion equipment is
Even if there is a surface corresponding to a half wavelength of the frequency from 800Hz to 3200Hz, it is not necessarily necessary to make all the corresponding surfaces non-parallel as long as the noise is reduced to a level that does not pose a problem during operation.

[Brief explanation of the drawing]

1 and 2 show a gas water heater according to a first embodiment of the present invention, FIG. 1 is a schematic front view thereof, and FIG.
The figure is a side sectional view, FIGS. 3 and 4 are partial front sectional views showing the outlines of the second and third embodiments, respectively, which are modified versions of the mixed case of the first embodiment, and FIGS. 5 and 6 5 shows the fourth embodiment of the present invention, FIG. 5 is a schematic front view thereof, FIG. 6 is a partial side sectional view, and FIGS. 7, 8, and 9 show the fifth embodiment of the present invention. FIG. 10 is a front view schematically showing the eighth embodiment of the present invention. In the figure, 11... combustion case (casing), 12
...Burner plate, 21...Mixing case (casing), 22...Blower, 24...Blower case (casing).

Claims (1)

[Claims] 1. A forced-air combustion device in which a burner having a flame outlet parallel to the ejection direction is disposed in a casing and combustion air is supplied by a blower, comprising: length is
A forced air combustion device characterized in that the surfaces corresponding to a half wavelength of sound from 800Hz to 3200Hz are non-parallel to the opposing surface. 2 A burner plate having a flame port whose ejection direction is parallel is arranged in a casing having an air supply port and an exhaust port to form a combustion chamber and a mixing chamber, and a blower casing equipped with an air blower is connected to the air supply port. in the forced air combustion device that is connected to the air blower and supplies combustion air to the mixing chamber by the blower, the length of the casing forming the mixing chamber with respect to the opposing surface is between 800 Hz and 3200 Hz. A forced air combustion device characterized in that a surface corresponding to a half wavelength of is made non-parallel to the opposing surface. 3. A forced-air combustion device comprising a burner having a flame port whose ejection direction is parallel to the casing having an air supply port and an exhaust port to form a combustion chamber, and a blower for supplying combustion air. In the casing forming the combustion chamber, a surface whose length corresponds to a half wavelength of sound from 800Hz to 3200Hz is made non-parallel to the opposing surface. Forced air combustion equipment. 4 A burner plate having a flame port whose ejection direction is parallel is disposed inside the casing to form a combustion chamber and a mixing chamber, and a blower casing equipped with an air blower is arranged in the burner plate of the casing forming the mixing chamber. connected perpendicularly to the surface facing the
In the forced air combustion device in which combustion air is supplied to the mixing chamber by the blower, the burner plate is arranged in a non-parallel plane with respect to a surface facing the burner plate. Combustion device.