JPS5997416A - Combustion device - Google Patents

Abstract

PURPOSE:To reduce dimensional sizes and lower a noise level of the titled device, by arranging such that the device comprises a burner adapted to burn a fuel with a primary and a secondary air, a secondary air jet orifice, a combustion chamber surrounding a flame and a combustion fan, being of pull type and provided at the downstream side of the burner for jetting out a secondary air to shorten a flame length. CONSTITUTION:A fuel enters into a fuel control valve 2 through a fuel supplying pipe 1 and is jetted out of a nozzle 3. An air is withdrawn by means of a pull type combustion fan 9' and divided into a primary and a secondary air under the control of primary air damper 4. The secondary air is jetted out of a secondary air jetting orifice 6. The primary air flows into a burner together with a fuel oil for being burnt in a combustion chamber 7. When the combustion is started, the secondary air is forcibly jetted out through the combustion fan 9' and impinges against a flame, and thereby significantly shortening the flame length and consequently eliminating the need of large space for the combustion chamber 7. A combustion gas enters into a heat exchanger 8 to heat up a water fed thereto from a water feed pipe 11 and the hot water is distributed through a hot water supply pipe 12.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a combustion device for heating or hot water supply by burning fuel such as gas or oil. The present invention relates to a combustion device whose purpose is to produce low noise even if the noise is low.

Conventional configuration and its problems As a conventional combustion device, n1 has the configuration shown in FIG.
There is something. 1 is a fuel supply pipe, 2 is a fuel control valve, 3 is a nozzle, 4 is a primary air damper, 6 is a burner, and 6 is a secondary air injection hole. 7 is a combustion chamber, and 8 is a heat exchanger. 9 is a combustion fan, 10 is an air supply port, 11 is a water supply pipe,
12 is a hot water supply pipe. Next, the operation will be explained. Fuel is supplied to the fuel supply pipe 1 through the fuel control valve 2 and is ejected through the plurality of nozzles 3. Air is supplied by a forced combustion fan 9
The secondary air is supplied from the secondary air supply port 1o, and the secondary air damper 4
The secondary air is controlled to be separated into primary air and secondary air, and the secondary air is blown out through the secondary air blow-off holes 6. - Air and fuel then enter the burner 6 and burn in the combustion chamber 7. At this time,
Since the secondary air is forced out during combustion, the flame becomes very short and the combustion chamber 7 becomes smaller. The combustion gas enters the heat exchanger 8 and heats the water supplied from the water supply pipe 11, which is then supplied from the hot water supply pipe 12.

Although this configuration has the advantage of making the combustion device compact, it also has the problem of extremely high combustion noise.

Purpose of the Invention The present invention is intended to solve such conventional problems, and aims to reduce the size of the device by shortening the flame by blowing out secondary air, and also to reduce the noise of the device. .

Structure of the Invention In order to achieve the above-mentioned object, - a burner that burns with secondary air and secondary air, a secondary air jet hole that blows out secondary air, a combustion chamber surrounding a flame, and - secondary air. The combustion fan to be supplied and Karana 9, the combustion fan is a tension type,
It is placed downstream of the burner.

Here, some conventional combustion devices are equipped with only a tension-type combustion fan to provide forced exhaust, but in this case, there is no secondary air injection hole and the device does not become smaller, so the present invention I would like to add that they have completely different purpose configurations.

DESCRIPTION OF EMBODIMENTS An embodiment of a water heater according to the present invention will be described with reference to FIG. Components that are the same as those in Figure 3 are marked with the same numbers, and 1
3 is an exhaust section.

Next, the operation will be explained. Fuel enters the fuel control valve 2 from the fuel supply pipe 1 and is ejected from the nozzle 3. Air is supplied by a tension type combustion fan 9, and is separated into primary air and secondary air under the control of a secondary air damper 4, and the secondary air is blown out from a secondary air jet hole 6. - Air and fuel enter the burner 5 and burn in the combustion chamber 7. At this time, the secondary air is forcibly blown out by the combustion fan 9 and hits the flame, so the flame becomes very short and the combustion chamber 7 becomes smaller. The combustion gas enters the heat exchanger 8, heats water supplied from the water supply pipe 11, and hot water is supplied from the hot water supply pipe 12. Due to the above-mentioned structural action, a low-noise device can be realized.
The reason for this will be explained using FIG. 2.

In FIG. 2, the horizontal axis is the frequency, and the vertical axis is the amplification factor as shown below.

(amplification factor) = (sound pressure during combustion) - (sound pressure during non-combustion) 2nd
As is clear from the figure, if the fan is used as a tension type, the sound pressure during non-combustion (that is, fan noise) is hardly amplified. However, if used as a push-in method, it can be seen that the sound pressure during non-combustion is amplified by about 15 clB. We were the first to invent this phenomenon,
The reason may be as follows. It has been known for a long time that flame has the effect of amplifying sound pressure, but this phenomenon is caused by the flame reacting to the sound pressure on the upstream side of the nozzle. Therefore, if the fan is located upstream of the burner (i.e., push type), the sound pressure will be amplified, but if the fan is located downstream of the burner (i.e., tension type), the sound pressure will be amplified. When it is fed back to the side, it is significantly attenuated because it passes through the -s 5 and the secondary air outlet 6.Also, of course, if there is no secondary air outlet 6, The sound pressure does not attenuate, and the difference in amplification factor as shown in Figure 3 does not appear.

Effects of the Invention By providing the secondary air outlet, the flame can be shortened, and by using a tension type fan, the device can be made to have low noise. This effect is about 15 dB compared to a push-in type fan. For example, if the noise of a push-in type combustion device is 5 odB (A), it is possible to reduce the noise to 36 dB (A) by using a tension type combustion device, which is extremely This is a big effect.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the water heater of the present invention;
FIG. 2 is a graph showing the difference in amplification factors between the push method and the tension method, and FIG. 3 is a front view showing a conventional example. 5... Burner, 6... Secondary air outlet, 7... Combustion chamber, 9... Combustion fan.

Claims (1)

[Claims] A burner that burns with primary air and secondary air, a secondary air outlet that blows out secondary air, a combustion chamber that surrounds a flame, and a combustion fan that supplies secondary air. This is a tension type combustion device installed downstream of the burner.