JPS6096831A - Safety device for indoor combustion device - Google Patents

Abstract

PURPOSE:To detect a polluted air in a simple and positive manner, by providing a group of flame ports having a flame port load greater than that for other portions at a part of burner independently from other groups of flame ports and by providing an abnormal combustion detecting element to orient toward the part of burner. CONSTITUTION:A group of flame ports 10 having a flame port load greater than that of flame port 10 defined through other portions (b) is provided at the part (a), for example, a side portion of frontal face of burner 6 independently from other portions. An abnormal combustion detecting element 9 is provided at the upper face of flame ports group b to orient toward the part (a). Upon a room oxygen becoming starved and the like, an abnormal combustion immediately takes place in some flame ports groups having a flame port load greater than that of other portions. Such abnormal combustion is detected by the abnormal combustion detecting element oriented toward the group, and thereby putting the flame out. The operational safety of device is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to a combustion safety device for a combustor installed indoors, such as an indoor open space heater or a small instantaneous water heater.

Conventional combustors of this type that discharge all exhaust gas into the chamber pose problems not only in the amount of carbon monoxide contained in the exhaust gas but also in the presence of NOx. For example, Japanese Patent Laid-Open No. 57-192740 shows that the amount of NOX decreases when combustion is performed at an excess air ratio (approximately 1.3 to 1.5) that is larger than the excess air ratio 1.
It is known from the publication No.

However, this stuff burns with an excess of air, so the indoor air becomes increasingly polluted; in other words, the oxygen concentration drops to around 18 to 16%, resulting in an oxygen deficiency. There is no struggle and the combustion is normal, but simply placing a combustion detection element such as a thermocouple on the top of the burner of the combustor cannot detect the desired 1B to 16%, which is inconvenient.

Therefore, the applicant first installed a small burner that requires secondary air in the combustion chamber in which the burner is installed, and a thermocouple that detects the combustion of the burner. We previously proposed a method that detects all signals and stops the burner combustion.

However, this method has the disadvantage that a separate small burner must be provided in the combustion chamber.

In view of the current situation, an object of the present invention is to provide a safety device that can easily and reliably detect indoor air contamination in a combustor that burns at an excess air ratio greater than the theoretical excess air ratio. This is a total air type burner that has a large number of flame holes installed in an airtight combustion chamber with only the exhaust port open, and is a type that burns with an air supply amount larger than the excess air ratio 1. In the burner, a part of the burner has a flame hole load larger than the flame hole load of the other part.
r is provided independently from other flame hole groups, and an abnormal combustion detection element for detecting abnormal combustion is provided in a part thereof,
The present invention is characterized in that combustion in the burner is stopped upon detection of abnormal combustion by the detection element.

Embodiments of the present invention will be described with reference to Attachment 1.

In the drawing, (1) shows the lower part r3i + the frame cylinder (3) equipped with the warm air outlet (2) is the airtight combustion chamber (
4) shows a fan for blowing hot air facing the lower part of the frame tube (1), and the combustion chamber (3) communicates with the outside only through two exhaust ports (5), and the inside thereof is equipped with a burner (6), and the burner (6) has an excess air ratio (1) larger than an excess air ratio (1).
, 3 to 1.5), and as shown in the figure, the burner (6) is heated by the suction of the fan (4).
(8) does not show the gas supply nozzle facing the intake port (force).

On the front side of the burner (6), there is a group of flame holes (10) with a flame hole load larger than the flame hole load of the flame hole 00) in the pond part 1IJb on a part a, for example, at the - side end. It is installed independently from other parts to prevent abnormal combustion from occurring on the upper surface of the group of flame holes.
The ever-changing '7δ needle-fired smart element (9) is now available.

To explain this in detail, part a has a large flame hole load (0) (
)) is a plate burner made of ceramic or the like having a large number of flame holes 00), for example, as shown in FIGS. The length of the flame hole group in part a is determined by the flame hole group in the other part (1,0
This length is shorter than that of +, thereby completely eliminating the passage resistance of each flame hole 00) in the flame hole group of part a and increasing the flame hole load.

That is, the gas wall per unit area of the flame hole was made larger than that of other parts.

In the embodiment shown in FIGS. 3 and 4, a hemispherical recess aυ is formed in a part of the surface of the plate burner (6) made of ceramic or the like, and an annular flame hole is formed on the outer periphery. A portion a21' without (If) was provided to make the flame hole group of part & independent from the flame hole group of the other portion.

However, the shape of the recess 01) is not limited to this, and may be rectangular with a flat bottom as shown in Figures 6 and 7. In this case, the portion 02) without the flame hole 00) is It is desirable to have a U-shape that surrounds the

In addition, in order to separate the flame hole group in part a from the flame hole groups in other parts, there are openings (13a) in the center that correspond to the flame hole groups in part a, as shown in the 7th south and in Figure 8. It is also possible to make the shielding plate 03 independent by placing it close to the front of the burner (6).

In addition, the flame hole group with a large load as described in AtJ is the flame hole 0ω of the part.
It can also be formed by making the diameter of the part slightly larger than that of other parts.

In the drawing, reference numeral 04) indicates that the on-off valve (15) interposed in the gas supply path A connected to the gas nozzle (8) is an electromagnetic valve, and the electromotive force of the thermocouple or other abnormal combustion detection element (9) Valve 051'fr: Directly or indirectly controlled to open and close.

(lη indicates a thermocouple facing the other flame hole part of the burner (6), and the electromotive force of the thermocouple u7) causes the fan (4) to
) The control circuit (19) of the motor (181) that drives the motor (181) is switched, for example, the amount of gas supplied to the burner (6) is reduced,
Along with this, when the temperature drops and the output of thermocouple 07 decreases, the rotation of the motor (stage) is reduced and the fan (4) described above is
) to adjust the amount of primary air intake from the intake port (power).

Next, the operation of this device a will be explained.

When the on-off valve 04) and the solenoid valve 05) are opened by an appropriate means from the outside, the burner (6) is ignited by an appropriate means, and the fan (4) is fully driven by the motor (181), the fan (4) is opened. The suction force sucks a large amount of air from the intake port of the burner (6), and the oxygen concentration in the room is normal (21%).
The burner (6) burns at an excess air ratio of about 1.3 to 1.5 when the burner (6) is close to the engine, and performs combustion with low NOx, which is not particularly different from the conventional example.

However, when the oxygen concentration in the indoor air decreases, the burner (6)
Abnormal combustion occurs, that is, the flame at the core extends first in the flame hole part where the flame hole load is large in part a, and as a result, the contact between the thermocouple (9) and the flame becomes incomplete, and the thermocouple (9) The electromotive force decreases rapidly. This is shown in Figure 9, in which
This shows that the electromotive force decreases rapidly when the oxygen concentration that we want to detect ranges from 18% to 16%.The flame hole group provided in part a of the burner with a large load is independent from the flame hole group in other parts. In the area without a flame hole for heating or without a shielding plate, as shown in FIG. 10, there was no sharp decrease in output at the oxygen concentration of 18% to 16%, which was particularly desired to be detected.

This seems to occur because the flame in the flame hole group a adjacent to the flame hole group A is pulled, and this high-temperature part comes into contact with the thermocouple (9).

The above characteristic curves are obtained by experimenting with 13A gas in the embodiments shown in FIGS. 3 and 4, with the maximum depth of the concave Ql) being 4+am, but the depth of the concave 0υ was varied. As shown in FIG. 11, it was found that when the electromotive force suddenly decreased, the value of the oxygen concentration changed. In Fig. 11, a indicates the depth of the concave Uυ is 4 gates, b indicates 3 ken, 0 indicates 2 ken, and d
is 0 and some flame holes are made independent from other parts,
Furthermore, as shown in FIGS. 5 and 6, it has been found that when the bottom is flat, the output characteristics of the thermocouple (9) change stepwise as shown in FIG. 12.

Incidentally, FIG. 13 is a characteristic curve of the thermocouple (9) of the embodiment shown in FIGS. 7 and 8.

Even if the mixing pipe (6a) of the burner (6) is clogged with lumps or the like and air cannot enter from the intake port (7), abnormal combustion may occur in part a of the burner (6) as described above. As described above, the combustion of the burner (6) can be stopped in the same manner as described above.As described above, according to the present invention, a group of flame holes having a flame hole load larger than that of other parts is provided in a part of the burner. In addition to being provided independently from other flame hole groups, an abnormal combustion detection element for detecting all abnormal combustion is placed in a part of the burner, and combustion of the burner is stopped when the detection element detects abnormal combustion. , when the indoor air becomes deficient in oxygen, abnormal combustion occurs quickly in some groups of flame holes that have a higher flame hole load than other areas, and the abnormal combustion elements that are present detect this and start combustion. It is safe because it can be stopped, and there is no need to worry about using a burner that separately detects oxygen deficiency, etc. like the one proposed earlier, and the plum fat is easy to use.

[Brief explanation of the drawing]

FIG. 1 is a cut front view showing one example of implementing the present invention. Figure 2 is a cutaway 1!9r side view, Figure 3 is an enlarged front view of the main part, Figure 4 is a plan view thereof, Figure 5 is an enlarged front view of the main part of a modified example, and Figure 6 is a plan view thereof, FIG. 7 is an enlarged cutaway front view of the main part of another modification, FIG. 8 is a plan view thereof, and FIG. 9 is a characteristic curve diagram of the embodiment shown in FIGS. 5 and 4. Fig. 10 is a characteristic curve diagram in a state where one part of the burner hole group is not independent from other burner hole groups, Fig. 11 is a characteristic 1-ga line diagram in a state where the depth of the striped depressions is varied, Figure 12 is the characteristic curve diagram shown in Figures 5 and 6, and Figure 13 is the characteristic curve diagram shown in Figure 7.
FIG. 8 and FIG. 8G are special semi-curve diagrams shown in FIG. (4)...Combustion chamber (5)...Exhaust port (9)...
・Abnormal combustion detection') l (I element 00)...flame hole a.
...／<- Part of the part b... Two other people outside the burner Fig. 3 Fig. 4. Figure 9

Claims (1)

[Claims] In an all-air type burner having a large number of flame holes ft provided in an airtight combustion chamber with only the exhaust gas 1 open, the burner burns with an air supply amount larger than the excess air ratio 1, In a part of the burner, a group of flame holes with a negative flame hole load higher than that of other parts is provided independently from the other groups of flame holes, and in the part, there is an abnormality for detecting abnormal combustion. A combustion safety device, characterized in that a combustion detection element is exposed, and combustion of the burner is stopped when abnormal combustion is detected by the detection element.