JPH0362969B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a forced air combustion device in which pressure loss is likely to occur due to the reduction in the size of the exhaust section in order to reduce noise during operation. The present invention relates to a forced air combustion device improved to suppress the occurrence of oscillatory combustion due to pressure loss.

[Prior Art] In recent forced-air combustion devices, such as instantaneous water heaters, air and fuel gas are forcibly supplied by a blower, combusted under high load in a combustion chamber, and water is transferred through a heat exchanger. can be heated to provide hot water.
After the fuel gas in the combustion chamber passes through the heat exchanger, it is discharged to the outside from the exhaust section as exhaust gas. In this case, combustion noise is likely to occur due to the high load combustion being carried out in the combustion chamber, and in order to reduce this combustion noise, the exhaust part is bent over the elbow,
Efforts are being made to increase the length of the passage or to provide a sound absorbing member in the exhaust section to obtain a noise reduction effect.

[Problems to be Solved by the Invention] However, with the above configuration, although combustion noise can be suppressed, the flow path resistance of the exhaust flow in the exhaust section becomes large, and the following new problems arise. In other words, as pressure oscillations and combustion reactions resonate with combustion in the combustion chamber, oscillatory combustion occurs.
Noise is generated due to this.

The present invention has been made in view of the above circumstances, and its object is to provide a forced air combustion device that can effectively suppress the generation of noise due to oscillatory combustion without hindering the reduction in combustion noise.

[Means for solving the problem] In order to achieve the above purpose, a combustion chamber is formed inside where combustion air is forcibly supplied and high-load combustion is performed, and the upper part of the combustion chamber is used as a heat exchange section. In a forced air combustion apparatus, the forced air combustion apparatus includes a combustion case, and an exhaust section having an exhaust passage provided inside an exhaust pan connected above the combustion case and an exhaust outlet formed on a wall surface. an inlet sound absorbing panel forming a narrow exhaust inlet between the section and the heat exchange section, the exhaust pan having a lower surface for deflecting an exhaust flow entering from the exhaust inlet, and an upper surface and the exhaust pan. An internal sound-absorbing panel is provided between the ceiling and the inlet panel to form an exhaust flow path through which the exhaust flow that has detoured around the lower surface flows out from the exhaust outlet, and further reduces the cross-sectional area of the exhaust outlet. A configuration is adopted in which a pressure outlet path is provided upstream or upstream of the internal sound absorbing panel to release the force generated in the heat exchange section or the exhaust section by the exhaust flow of combustion operation to the outside.

[Operations and Effects of the Invention] According to the present invention, the exhaust section is provided with a double throttling means consisting of an internal sound absorbing panel and an inlet sound absorbing panel to reduce combustion noise. This is an excellent forced-air combustion system that can effectively suppress the occurrence of oscillatory combustion with a small cross-sectional area of the pressure outlet, as the pressure increase in the exhaust section is released to the outside through the pressure outlet. can be provided.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show an instantaneous gas water heater to which the forced air combustion device of the present invention is applied.

In this example, a forced air combustion device was applied to the instantaneous gas water heater 1. The instantaneous gas water heater 1 is housed in a main body case 10, and includes a combustion section 2, a heat exchange section 3, a centrifugal blower 7 which is a supply section that supplies combustion air to the combustion section 2, and a gas supply path. 8 and an electronic control device 9. The main body case 10 has an opening 11 that takes in combustion air and an opening 12 that exhausts combustion exhaust.

The combustion section 2 includes a combustion case 20 provided with an exhaust section 4 on the upper part, and a fixing fitting 21 on the combustion case 20.
A combustion chamber 23 equipped with a ceramic combustion plate type gas burner 22 which is attached through a ceramic plate body and has a large number of injection holes in a ceramic plate body;
A mixing chamber 24 is provided at the bottom of the mixing chamber 24. The heat exchange section 3 consists of a plate fin group 31 that increases heat exchange efficiency, a water supply pipe 32, and a hot water supply pipe 33, and is arranged between the gas burner 22 and the exhaust section 4, and hot water is sent from upstream of the supply pipe 32. The water is exchanged with the combustion exhaust in the combustion chamber 23. As shown in FIGS. 4 to 6, the exhaust section 4 has an inlet section 41a and a bent section 41b.
and a rectangular exhaust outlet 4 that opens toward the outside.
It consists of an exhaust pan 42 and an exhaust hood 6, in which an exhaust passage 41 having a diameter 1c is formed. As shown in FIG. 4, the exhaust pan 42 is attached to the upper part of the combustion case 20, and is made up of the upper and lower surfaces of a sound absorbing material 43c in which a large number of rectangular exhaust inlets 43a forming exhaust inlets of the exhaust passage 41 are opened in a staggered manner. An exhaust inlet sound absorbing panel 43 is provided at the lower part 42a, with the exhaust air inlet sound absorbing panel 43 sandwiched between diamond-shaped wire meshes (lath metal) 43b for protection. Furthermore, the exhaust pan 42 has an exhaust passage 4 opened on the back side.
Internal sound-absorbing panels 45 and 46 that hold sound-absorbing materials 43d and 43e arranged to reduce the opening area of the exhaust outlet 41c of No. 1, and a ceiling sound-absorbing panel 47 that holds sound-absorbing material 43f provided on the upper part 42b.
and an upper plate 48. These sound absorbing panels 43, 45, 46, 47 are held within the exhaust pan 42 by a holding frame 44.

In this state, the internal sound-absorbing panel 45 protrudes into the exhaust passage 41, making the sound-absorbing effect of the sound-absorbing material 43b effective, as will be described later in the explanation section.

Further, the holding frame 44 has an opening 44 provided to form an exhaust outlet 41c of the exhaust passage 41.
a, an inner circumferential edge 44 provided on the inner circumference of the opening 44a;
b, and extends from the lower edge 44c of the inner circumferential edge 44b to a point that reduces the opening area of the exhaust outlet 41c of the exhaust passage 41. Further, in the internal sound absorbing panels 45, 46 and the ceiling sound absorbing panel 47, a large number of circular through holes are formed in the sound absorbing materials 43d, 43e, 4.
3f is bored to expose it to the exhaust passage 41.

The exhaust hood 6 is connected to the exhaust outlet 41 of the exhaust passage 41.
As shown in FIGS. 5 and 6, it is attached to sandwich the outer peripheral edge 44h of the holding frame 44, and has slit-shaped exhaust ports 65a, 65b and similar holes on both left and right sides. Exhaust port 65
c and 65d are formed in two upper and lower stages. Also,
In the exhaust heat 6, a pressure equalizing hole 200 is formed below and close to the exhaust port 65b, and arranged vertically with the other exhaust ports 65a.

Now, a through hole 100 is formed in the holding frame 44e so as to communicate with the passage space S between the internal sound absorbing panel 45 and the heat exchange section 3. Reference numeral 101 denotes a pressure equalizing pipe bent into a crank shape, which functions as a pressure outlet path as the gist of the present invention, and has an interior thereof as the outlet path 101a. This pipe 101 has one end communicating with the through hole 100 and the other end communicating with the pressure-limiting hole 200 in the exhaust hood 6. Note that 67 is a mounting hole through which the exhaust hood 6 is fastened to the holding frame 44 with a screw or the like.

On the other hand, the centrifugal blower 7 includes a scroll casing 71, a fan 72, and a driving motor 73 for the fan 72. scroll casing 7
1 is a cylindrical body 75 that has a spiral shape and is fastened to a side surface 74; and a shielding plate 76 that is fastened to the cylindrical body 75.
and a dustproof net 77 that covers the shielding plate 76.

The cylindrical body 75 forms a bell-mouth-shaped suction port 78 that is open to the outside, and its tip 79 fits into the fan 72 by a predetermined dimension in consideration of the rotational speed of the centrifugal blower 7 .

As shown in FIG. 7, the shield 76 has a conical part 76b with a tip 76a located at the center of a bellmouth-shaped suction area 78, and a circle extending along the outer periphery from the other end 76c of the conical part 76b. A plate portion 76 and three L-shaped mounting legs 76 hanging down from the disk portion 76b.
e, and three L-shaped dustproof net attachment parts 76f that are connected from the disc part 76d. The L-shaped dustproof net mounting part 76 has three L-shaped mounting legs 76e.
Since the outer periphery is extended from f, the shielding plate 7
6 and the dustproof net 77 can be attached to the cylindrical body 75 after being assembled in advance.

The gas supply path 8 is integrally molded with the scroll casing 71 and includes a gas jet nozzle 81 that discharges fuel gas, a gas supply pipe 82 that supplies fuel gas to the gas jet nozzle 81, and a gas control unit 83. Become. Gas control unit 8
3 is an electromagnetic on-off valve 84 that is provided between the gas ejection nozzle 81 and the gas supply pipe 82 and opens and closes by energization and specific energization, and an electromagnetic on-off valve 84 that is provided downstream of the on-off valve 84 to adjust the gas flow rate. It is provided with a governor valve (not shown) and an electromagnetic proportional control valve 85 which is provided downstream of the governor valve and whose opening ratio is varied according to the amount of current supplied. An orifice 86 is attached to the other end of the gas injection nozzle 81 to adjust the supply pressure and flow rate of fuel gas.

The electronic control device 9 includes a start switch (not shown) that turns on the instantaneous gas water heater 1, and a temperature adjustment knob (not shown) that is scanned by the user and sets the temperature of the water flowing out from the hot water pipe 33. (not shown),
A spark electrode 92 that blows sparks on the combustion surface of the gas burner 22 at the time of ignition in response to input from a thermocouple 91 that detects the oxygen supply state of the flame of the gas burner 22, a driving motor 73 of the centrifugal blower 7, and a gas control unit. Controls energization and de-energization of devices such as 83.

Next, the operation of the above configuration will be explained.

In the instantaneous gas water heater 1, when the start switch is turned on, the fan of the centrifugal blower 7 rotates and blows combustion air from the scroll casing 71 to the gas burner 22.
supply to. Then, the electronic control device 9 controls the on-off valve 84 and the comparison control valve 8 of the gas control unit 83.
5, the on-off valve 84 and the proportional control valve 85
Open the door. Further, the combustion air existing outside the scroll casing 71 has dust and dirt removed by the dustproof net 77 and is sucked into the cylindrical state 75 while the flow rate of the combustion air is throttled.

Then, the spark electrode 92 is controlled by the electronic control device 9.
A spark discharge occurs at the gas burner 22, and the gas burner 22 is ignited and starts combustion. Thereafter, the combustion exhaust gas from the gas burner 22 passes through the heat exchange section 3 as an exhaust stream and reaches the exhaust passage 41 of the exhaust section 4 . In this process, the water from the water supply pipe 32 is heat exchanged with the exhaust flow by the heat exchanger 3 and is supplied from the hot water supply pipe 33 as hot water. Thereafter, the exhaust flow is directed to the exhaust inlet 4 of the inlet sound absorbing panel 43.
3a from the exhaust outlet 41c, and then the exhaust ports 65a, 65b, 6c5, 6 of the exhaust hood 6.
It is discharged from d5.

At this time, the exhaust passage 41 is first narrowed by the inlet sound absorbing panel 43, and then the internal sound absorbing panel 45 protrudes to further narrow the exhaust outlet 41c, resulting in a large flow path resistance of the exhaust flow.
In this configuration, the pressure equalizing pulp 10 is used as a pressure outlet path.
1, the flow path space S is equalized by the pressure equalizing pipe 101.
It is released to the outside through the lead-out path 101a. In this embodiment, the inlet of the pressure equalizing pipe 101 is opened on the lower surface side of the internal sound absorbing panel 45, which is a large flow path area upstream of the non-air outlet 41c, which is a constriction part.
In this part, the flow rate of exhaust gas is slow and the static pressure is therefore high, so even a relatively thin pipe can have a large pressure relief effect. For this reason, the internal sound absorbing panel 45
The pressure in the flow path space S between the combustion chamber and the heat exchange section 3 is prevented from increasing, the generation of induced vibrations is effectively controlled, and there is no generation of resonance noise caused by combustion vibrations. Due to the interaction between the double throttle between the exhaust inlet 43a and the exhaust port 43e and the pressure equalizing pipe 101, it is also possible to eliminate vibrational combustion noise that occurs especially in an unstable state of combustion immediately after ignition.

As is clear from the above, according to the present invention, in order to reduce combustion noise, the exhaust section 4 is provided with a sound absorbing material with a throttling function that acts as a flow path resistance, but it is also effective in preventing pressure loss and generating combustion vibrations. It has excellent effects when controlled.

Furthermore, since the pressure equalization holes 200 are provided close to the exhaust port 65b, the pressure equalization holes 200 are arranged vertically in line with the exhaust port 65b that originally exists, which impairs the design appearance. The effects of the embodiment described above can also be obtained.

Furthermore, a straight pressure equalizing pipe is used instead of the crank-shaped pressure equalizing pipe 101, and the exhaust hood 6
It may be provided in a penetrating state. Alternatively, the through hole 10
0, the pressure equalizing pipe 101 may be omitted, and the through hole 100 may be configured to communicate with the exhaust ports 65a to 65d via the space between the holding frame 44 and the exhaust hood 6.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, a through hole 100 with a diameter of 5 mm is formed on both left and right sides of the holding frame 44 instead of the through hole 100 and pressure equalizing pipe 101 of the previous embodiment, and between the holding frame 44 and the exhaust hood 6. Partition plate 3
00, and the opening 44a and the through hole 100 are partitioned by the partition plate 300. The passage space S' between the inlet sound absorbing panel 43 and the heat exchange section 3 and the inside of the exhaust hood 6 are communicated through the through hole 100 . Furthermore, a hole 400 is formed in the exhaust fan 6,
Due to this extraction hole 400, the flow path space S' is expanded to the through hole 100.
and communicates with the outside via the inside of the hood 6.

According to this configuration, the exhaust inlet 43 which is the throttle part
Since the through hole 100 as a pressure outlet path is provided just before the point a, the same effect as in the first embodiment can be obtained. Furthermore, the flow path space S′, the through hole 100 and the extraction hole 4
Since the passage through which the 00s communicate with each other is not obstructed by the exhaust flow through the opening 44a, a good low noise effect can be obtained.

In addition, the forced air combustion apparatus of the present invention may be applied to a heating apparatus, and various other changes may be made without departing from the spirit of the invention.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing an instantaneous gas water heater to which an embodiment of the forced air combustion device of the present invention is applied, and Fig. 2 is a side sectional view showing an instantaneous gas water heater to which an embodiment of the forced air combustion device of the present invention is applied. A front sectional view showing an instantaneous gas water heater; FIG. 3 is a front view showing an instantaneous gas water heater to which an embodiment of the forced air combustion device of the present invention is applied;
FIG. 4 is a perspective view of an exhaust pan attached to an instantaneous gas water heater to which an embodiment of the forced-air combustion device of the present invention is applied, and FIG. 5 is an embodiment of the forced-air combustion device of the present invention. 6 is a side sectional view of FIG. 5, and FIG. 7 is a front view of an exhaust hood attached to an instantaneous gas water heater to which an embodiment of the forced air combustion device of the present invention is applied. FIG. 8 is a perspective view of a shielding plate attached to a gas water heater, and FIG. 8 is a longitudinal cross-sectional view of main parts in another embodiment. In the figure, 1... Instantaneous gas water heater, 3... Heat exchange section, 4... Exhaust section, 20... Combustion case, 23...
...Combustion chamber, 41...Exhaust passage, 41c...Exhaust outlet, 42...Exhaust pan, 43...Inlet sound absorption panel, 43a...Exhaust inlet, 45...Internal sound absorption panel, 100...Through hole (pressure derivation) road), 101...
Pressure equalization pipe (pressure outlet path).

Claims (1)

[Scope of Claims] 1. A combustion case which forms a combustion chamber inside which combustion air is forcibly supplied to perform high-load combustion, and whose upper part is a heat exchange section; and a combustion case connected above the combustion case. In a forced air combustion apparatus, the forced air combustion device is provided with an exhaust passage formed inside an exhaust pan, and an exhaust section having an exhaust outlet formed on a wall surface, wherein a narrow exhaust section is provided between the exhaust section and the heat exchange section. An inlet sound absorption panel forming an inlet is provided, the exhaust pan having a lower surface that deflects an exhaust flow flowing in from the exhaust inlet, and an exhaust flow that bypasses the lower surface between the upper surface and the exhaust pan ceiling. An internal sound absorbing panel is provided to form an exhaust flow path through which the exhaust gas flows around and flows out from the exhaust outlet, and further reduces the cross-sectional area of the exhaust outlet, and upstream of the inlet sound absorbing panel or upstream of the internal sound absorbing panel, a combustion operation 1. A forced-air combustion device characterized by being provided with a pressure outlet path for releasing the pressure generated in the heat exchange section or the exhaust section to the outside by the exhaust flow.