JPH01225811A - Combustion device - Google Patents

Abstract

PURPOSE:To reduce the generation of noise, by a method wherein when a fluctuation in a pressure occasioned by combustion is produced in the combustion chamber of a combustion device, e.g. an instantaneous water boiler, a fluctuation in a pressure is absorbed by means of a number of pores formed in the wall surface of a combustion case and a cover with which the pores are covered. CONSTITUTION:An instantaneous gas water boiler 1 is provided with a combustion chamber 2, a body case 4 having a heat exchanger 3 disposed to the upper part of the combustion chamber, and a centrifugal blower 5 with the aid of which combustion air is fed to the combustion chamber 2. A number of pores 13 are formed in the portion, where the combustion chamber 2 is formed, and the portion, having the heat exchanger 3, of the wall surface of the body case 4, and a cover 14 is airtightly mounted in a manner to cover the pores therewith. A sound absorbing material 15, e.g. glass wool, is situated between the cover 14 and the body case to the upper part of a discharge port 11. When a fluctuation in a pressure is produced in the body case 4 due to combustion, a fluctuation in a pressure is absorbed in the cover 14 through a number of the pores 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion apparatus that performs high-load combustion by forcibly supplying combustion air to a combustion chamber.

[Prior Art] For example, in a combustion device such as a household instantaneous water heater, fuel gas and air are mixed and forcibly supplied to a combustion chamber by a blower to perform high-load combustion.

Combustion gas generated by combustion undergoes heat exchange with water in a heat exchanger, and then is discharged to the outside from an exhaust section as exhaust gas.

In this case, since high-load combustion is performed in the combustion chamber, combustion noise is generated due to pressure fluctuations within the combustion chamber.

In order to reduce this combustion noise, conventional methods have been used to create a sound-deadening effect by bending the exhaust passage that makes up the exhaust section, increasing the length of the passage, or attaching sound-absorbing materials to the exhaust section. was.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the combustion noise generated due to pressure fluctuations during combustion is muffled in the exhaust section, and therefore the expected sound muffling effect cannot be obtained. It had some problems.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a combustion device that absorbs pressure fluctuations within a combustion chamber and reduces combustion noise.

[Means for Solving the Problems] In order to achieve the above object, the first invention forms a combustion chamber in which combustion air is forcibly supplied and burns fuel, and the wall surface of the combustion chamber is formed. The technical means includes a combustion case in which a large number of small holes are opened, and a cover airtightly attached to the combustion case from the outside of the combustion case so as to cover the large number of small holes.

Further, the second invention includes a combustion chamber to which combustion air is forcibly supplied to combust the fuel, and a heat exchanger disposed therein to exchange heat between the combustion gas generated in the combustion chamber and a fluid. and a heat exchanger case having a large number of small holes in a wall surface, and a cover airtightly attached to the heat exchanger case from the outside of the heat exchanger case so as to cover the large number of small holes. This is a technical means.

Functions and Effects of the Invention] (First Invention) The first invention having the above configuration has a large number of small holes formed in the wall surface of the combustion case forming the combustion chamber, and the large number of small holes are opened from the outside of the combustion case. By providing a cover to cover the combustion chamber, when pressure fluctuations occur due to combustion within the combustion chamber,
The pressure fluctuations are absorbed within the cover attached to the combustion case through the small holes, reducing combustion noise associated with pressure fluctuations.

Thereby, the combustion noise can be further reduced compared to the conventional case where the generated combustion noise is muffled or absorbed in the exhaust section.

(Second Invention) On the other hand, the second invention having the above-mentioned configuration is such that a large number of small holes are opened in the wall surface of a heat exchanger case equipped with a heat exchanger, and the large number of small holes are opened from the outside of the heat exchanger case. By providing a cover to cover the combustion chamber, when pressure fluctuations occur due to combustion in the combustion chamber, the pressure fluctuations are absorbed within the cover attached to the heat exchanger case through the small holes, and the combustion caused by the pressure fluctuations is absorbed. Reduce noise.

As a result, similarly to the first aspect of the invention, the combustion noise can be further reduced compared to the conventional case in which the generated combustion noise is muffled or absorbed in the exhaust section.

[Example] Next, an example of the combustion apparatus of the present invention will be described based on the drawings.

FIG. 1 is a side sectional view of an instantaneous gas water heater to which the combustion device of the present invention is applied, and FIG. 2 is a front sectional view of the instantaneous gas water heater shown in FIG.

As shown in FIG. 2, this instantaneous gas water heater 1 forms a combustion chamber 2 in which fuel is combusted, and a heat exchanger installed in the upper part of the combustion chamber 2 (on the "-" side in FIG. 2). a main body case 4 including a combustion chamber 3; a centrifugal blower 5 that supplies combustion air to the combustion chamber 2; and a gas supply path 6 that supplies fuel gas to the combustion chamber 2.
and an electronic control circuit 7 that controls the combustion state in the combustion chamber 2.

Note that the main body case 4 constitutes a combustion case and a heat exchanger case of the present invention.

The combustion chamber 2 has a large number of ejection holes 8a in a ceramic plate.
A combustion plate type gas burner (hereinafter abbreviated as burner) 8 is provided.

The burner 8 is fixed in the main body case 4 by a frame-shaped fixing fitting 10 together with a ceramic refractory frame 9 fitted around the outer peripheral edge of the burner 8 .

The heat exchanger 3 includes a heat exchange pipe 3a whose one end is connected to a water supply pipe (not shown) and the other end is connected to a hot water supply pipe (not shown), and a plate fin group 3b that increases heat exchange efficiency. configured. The heat exchanger 3 heats the water supplied from the water supply pipe to the heat exchange vibe 3a by exchanging heat with the combustion gas generated in the combustion chamber 2, and then flows out to the hot water supply pipe.

At the upper part of the main body case 4 (upper side in Figure 1), there is an exhaust Dll for exhausting combustion gas generated by combustion in the burner 8.
is formed, and its exhaust port 11 is connected to an exhaust pipe (not shown) communicating with the outside of the main body case 4. Further, a mixing chamber 12 is formed upstream of the combustion chamber 2 (lower side in FIG. 1) to mix combustion air and fuel gas and supply the mixture to the burner 8.

As shown in FIG. 1, a large number of small holes 13 are formed in the front wall surface (left side in FIG. 1) and back wall surface of the main body case 4 in the portion forming the combustion chamber 2 and the portion including the heat exchanger 3. There is. Furthermore, covers 14 are installed on the front wall surface and the back wall surface of the main body case 4 from the outside of the main body case 4 so as to cover the large number of small holes 13 opened in the main body case 4.
is installed airtight.

The space formed between the cover 14 and the main body case 4 is filled with a sound absorbing material 15 such as glass wool, and the sound absorbing material 15 is similarly attached to the upper part of the exhaust port 11.

The centrifugal blower 5 includes a scroll casing 16 and a fan 1
7 and a fan motor 18 , and a discharge port 16 a of the scroll casing 16 is connected to the mixing chamber 12 .

The gas supply path 6 includes a gas supply pipe 19 having a gas injection nozzle 19a that injects fuel gas into the scroll casing 16, a flow rate control valve 20 provided in the gas supply pipe 19 that adjusts the flow rate of the fuel gas, and Safety valve 2'1 that automatically shuts off the fuel gas supply in the event of a gas leak, etc.
It consists of

The electronic control circuit T includes a spark electrode 22 which is an ignition device that causes sparks to fly off the front surface of the burner 8 at the time of ignition, a thermocouple 23 which is a combustion sensor that detects the oxygen concentration (air-fuel ratio) of the combustion flame, and the above-mentioned thermocouple 23. It drives and controls the flow rate control valve 20, the safety valve 21, the fan motor 18 of the centrifugal blower 5, and the like.

Next, the operation of this embodiment will be explained.

When the user turns on a starting switch (not shown), the fan motor 18 of the centrifugal blower 5 is driven via the electronic control circuit 7, and combustion air is taken in. At the same time, the flow rate control valve 20 and the safety valve 21 are opened by the output of the electronic control circuit 7, so that the gas supply pipe 1
9 is supplied with fuel gas, and the fuel gas is injected into the scroll casing 16 from the gas injection nozzle 19a.

Thereafter, the fuel gas mixed with combustion air is supplied to the burner 8, and is ignited by spark discharge from the spark electrode 22 to begin combustion.

The combustion gas generated by combustion in the burner 8 exchanges heat with water supplied from the water supply pipe to the heat exchange vibe 3a when passing through the heat exchanger 3, and is then discharged from the exhaust pipe through the exhaust port 11. be done.

The heated water exchanges heat with the combustion gas and flows out to the hot water pipe as hot water.

In the above operation, when pressure fluctuation occurs in the main body case 4 including the combustion chamber 2 and the heat exchanger 3 due to combustion, the pressure fluctuation propagates inside the main body case 4 as a sound wave.
Pressure fluctuations are absorbed within the cover 14 through the numerous small holes 13 formed in the main body case 4, and the kinetic energy of the sound generated by the pressure fluctuations is converted into thermal energy by the sound absorbing material 15 filled within the cover 14. be done.

As a result, it is possible to reduce combustion noise caused by pressure fluctuations during combustion, and compared to the conventional method of muffling or absorbing generated combustion noise in the exhaust section, it is possible to reduce combustion noise. You can get a big effect.

The size, shape, number, etc. of the large number of small holes 13 formed on the front and back walls of the main body case 4 are appropriately determined within a range that reduces combustion noise.

(Modified Example) In the above embodiment, the small hole 13 is provided in the wall surface of the main body case 4 forming the combustion chamber 2 and the wall surface of the main body case 4 in which the heat exchanger 3 is disposed. The small hole 13 may be formed in only one of the walls of the main body case 4 forming the heat exchanger 3 and the wall surface of the main body case 4 on which the heat exchanger 3 is disposed.

A main body case 4 forming a combustion chamber 2 in the combustion device of the present invention
Although applied to an instantaneous gas water heater 1 equipped with a heat exchanger 3 inside, the combustion device is formed by separating a combustion case forming a combustion chamber 2 and a heat exchanger case equipped with a heat exchanger 3. May be applied to In this case, small holes 13 may be formed only on the wall surface of the combustion case or only on the wall surface of the heat exchanger case.
You may also open a

Although the case in which the heat exchanger 3 is provided is illustrated, the present invention may also be applied to a combustion device that does not have the heat exchanger 3, such as a fan heater.

Although the cover 14 is exemplified as being filled with the sound absorbing material 15 such as glass wool, the inside of the cover 14 may be used as a cavity without being filled with the sound absorbing material 15.

Furthermore, when using the sound absorbing material 15, in addition to the above-mentioned glass wool, porous synthetic resin, fibrous felt, or the like may be used.

Although the combustion device of the present invention is applied to an instantaneous gas water heater, it may be applied to other combustion devices such as a combustion type heating device.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an instantaneous gas water heater to which the combustion device of the present invention is applied, and FIG. 2 is a front sectional view of the instantaneous gas water heater shown in FIG. In the diagram 1... Instantaneous gas water heater (combustion device) 2...
Combustion chamber 4... Main body case (combustion case and heat exchanger case) 13... Small hole 14... Covered/instantaneous gas water heater (combustion device) 2... Combustion chamber 4... Main body case (combustion case and heat exchanger case) 13...small hole 14...on the cover\1617

Claims (1)

[Scope of Claims] 1) (a) A combustion case in which a combustion chamber is formed into which combustion air is forcibly supplied and fuel is combusted, and a large number of small holes are formed in the wall of the combustion chamber; b) A combustion device comprising: a cover airtightly attached to the combustion case from the outside of the combustion case so as to cover the large number of small holes. 2) (a) A combustion chamber to which combustion air is forcibly supplied to combust fuel, and (b) a heat exchanger inside to exchange heat between the combustion gas generated in the combustion chamber and a fluid. (c) a cover airtightly attached to the heat exchanger case from the outside of the heat exchanger case so as to cover the large number of small holes; A combustion device comprising: