JPH02275215A - Burner - Google Patents

Abstract

PURPOSE:To reduce the component of a low frequency and minimize the noise during combustion without enlarging the equipment size and increasing the pressure loss by installing a sound absorbing section having a plurality of pipelines whose opening length varies within an apparatus main body designed to supply fuel with one end closed and the other end opened. CONSTITUTION:A plurality of pipelines 28 whose length varies are installed between an outside case 24 and an apparatus main body 14 based on a pipe length l where a frequency corresponds with a resonance component of Helmholtz f0 produced in the apparatus main body by combustion in such a manner that one end may be closed while the other end may be opened to a waste duct 21. The installation of a sound absorbing section 29 which comprises a plurality of pipelines whose length varies to meet the resonance component and opened inside the apparatus main body 14 allows the resonance component to be absorbed into the aforesaid pipelines inside the apparatus main body 14, thereby providing the effect of sound reduction in a low frequency band.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to noise reduction in domestic combustion machines such as water heaters and space heaters.

BACKGROUND OF THE INVENTION Conventionally, this type of combustion apparatus has had a configuration as shown in FIG.

That is, a fan 1, a burner 2, a combustion chamber 3, a heat exchanger 4, an exhaust hood 5, and an exhaust port 6 are connected in order from the upstream side along the air flow while maintaining airtightness. A fuel supply system 7 is connected to the heat exchanger 4, a water supply pipe 8 and a hot water outlet pipe 9 are connected to the exhaust hood 5, and a perforated plate 10 is connected to the exhaust hood 5.
Resonance chamber 11 is connected via. Here, perforated plate 1
0 and the resonance chamber 11 are designed to match the resonance frequency of the combustion system, forming a resonance type muffler. A sound absorbing material may be installed inside the resonance chamber 11. In addition, as another conventional example, a partition plate 13 having a constriction part 12 is provided inside the exhaust hood 5 as shown in FIG. was. (For example, Japanese Utility Model Application Publication No. 59-62446) Problems to be Solved by the Invention However, in the above configuration, in order to reduce the low frequency band that is the main component of noise during combustion in the combustor, the exhaust passage is The thickness of the sound-absorbing material and the size of the resonant muffler must be considerably increased, which limits the installation space, increases the size of the equipment, and causes the muffler itself to resonate (generate secondary noise). It had Furthermore, with the expansion type muffler, the exhaust pressure exceeds the limit due to the resistance of the throttle part, making it necessary to use a larger fan and a rotational speed amplifier, making it impossible to achieve an overall noise reduction effect.

The present invention is intended to solve such conventional problems, and aims to reduce noise during combustion by reducing low frequency components without increasing the size of equipment or increasing pressure loss.

Means for Solving the Problems In order to solve the above problems, the combustion apparatus of the present invention includes a combustion section having a burner and a combustion chamber, an exhaust section having an exhaust duct and an exhaust port, and an air blower for supplying air to the burner. A sound absorbing section having a plurality of conduits of different lengths, one end of which is closed and the other end of which is open into the instrument main body, is provided in an instrument body having a fuel supply mechanism section and a fuel supplying mechanism section.

Operation The combustion device of the present invention has one end closed due to the above configuration, and
An acoustic filter called a side branch is configured, the other end of which opens into the instrument body, and the target frequency and the reduced volume are determined by equations (1) and (2), respectively.

f=c/41...(1) where f is the frequency, C is the speed of sound, 1 is the tube length, A is the reduced volume,
a indicates the tube diameter.

Therefore, for a Helmholtz resonance component molecule 0 generated in the instrument body due to combustion, the pipe length 1 where the r coincides with fo
By installing multiple pipes of different lengths around the main body of the instrument, the sound of the target frequency is absorbed by the pipes, and as a result, the sound of the resonance beak r0 is attenuated, and the sound from the exhaust port to the equipment is absorbed by the pipes. It is released to the outside.

Embodiment Hereinafter, an embodiment of the present invention will be described in the case of a gas water heater based on the attached drawings.

Figures 1 and 2 show a gas water heater.
The combustion section 17 is provided with a blower section 18 for supplying combustion air and a mechanism section 19 for supplying fuel on the upstream side of the combustion section 17, and an exhaust section 23 having a heat exchanger 20, an exhaust duct 21 and an exhaust port 22 on the downstream side. It is surrounded by a front case 24 and a back case 25. The front case 24 also has an opening 26 through which the exhaust port 22 passes, and an air supply port 2 that is an air intake port.
7, and a third
A sound absorbing section 29 consisting of a plurality of pipes 28 having different lengths, one end of which is closed and the other end is open to the exhaust duct 21 as shown in the figure.
is installed.

In the above configuration, pressure fluctuations occur within the appliance main body 4 due to combustion in the burner 15, resulting in combustion chamber 16 and exhaust dug 1.
-21, etc., and is emitted to the outside mainly from the exhaust port 22, and this component accounts for a large portion of the noise of the water heater. However, since the sound absorbing section 29 is opened into the instrument main body 4 and is composed of a plurality of conduits 28 having different lengths according to the resonance components,
Resonance components within the instrument body 4 are absorbed by the pipe 28, and as shown in FIG. 4, a sound reduction effect is obtained in the low frequency range. In addition, the installation position of the pipe line 2B is the exhaust duct 2 in this embodiment.
1, it is provided on the inner surface of the instrument body 4, but it may be opened anywhere on the rear or side surface, and the opening is not limited to the exhaust duct 21, but may be opened anywhere on the instrument body.

Effects of the Invention As described above, the combustion apparatus of the present invention provides the following effects.

(1) The instrument body is provided with a plurality of conduits of different lengths, one end of which is closed and the other end of which is open inside the instrument body, to constitute a plurality of acoustic filters, so that resonance components generated within the instrument body are The sound reduction effect in the low frequency range, which is absorbed by the pipe and is particularly difficult to reduce, can be obtained without increasing the size of the instrument body or increasing the pressure.

(2) Since the frequency at which sound is attenuated differs for each pipe, acoustic energy is dispersed in each pipe, making it difficult for resonance of the constituent members themselves to occur, which occurs when using a resonant muffler.

(3) In addition, the length of the pipe is not limited to a straight line; the same effect can be obtained even if it is curved, and it can be installed anywhere on the device itself, so there is no space for installation inside the device. can be used effectively.

(4) By arbitrarily setting the number and diameter of the pipes in accordance with the frequency components and attenuation amounts to be reduced, effective noise reduction can be achieved easily.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the main parts of a gas water heater equipped with an embodiment of the present invention, Fig. 2 is a perspective view of the external appearance with the case removed, Fig. 3 is a sectional view of the sound absorbing part, and Fig. 3 is a sectional view of the sound absorbing part. FIG. 4 is a frequency characteristic diagram showing the effect, and FIGS. 5 and 6 are vertical cross-sectional views of main parts of a conventional gas water heater. Tail: Equipment body, 15: Burner, 1
6... Combustion chamber, 17... Combustion part, 18
...Blower section, 21...Exhaust duct, 2
2... Exhaust port, 23... Exhaust part, 28
...Pipe line, 29...Sound absorption part. Name of agent Patent attorney Shigetaka Awano 1 person Fig. 1 2.3 /4 ′-M section main body/S , - burner 16 - 11 1γ゛-, moon I sitting t8-゛° feed- skin Part 2 / - Old To Qi Duct 22 - - - η To qi ton 7 ゜ 23 ・ - Saishou Qi Part zq - - 1 No Poverty Old Part Figure 3? 8 Figure Figure & Y & S4 ρ ri 5 ρ O Shoulder浚＠：(H7-,) Figure/f Funeral map

Claims (1)

[Claims] A device body including a combustion part having a burner and a combustion chamber, an exhaust part having an exhaust duct and an exhaust port, a blower part for supplying air to the burner, and a mechanism part for supplying fuel, with one end closed, A combustion device comprising a sound absorbing section having a plurality of pipes having different lengths, the other end of which opens into the instrument main body.