JPH0733892B2 - Combustion device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a combustion device equipped with a catalyst for purifying exhaust gas, which is used for heating, heating, drying and the like.

2. Description of the Related Art Combustion equipment such as stoves and fan heaters that burn oil and gas are equipped with catalysts for exhaust gas purification, and there are some that purify by oxidizing unburned components and carbon monoxide contained in exhaust gas. Although it is in practical use, it has a conventional flat plate structure and is installed horizontally above the combustion chamber so as to cover its exhaust port, or horizontally, that is, at a substantially right angle to the exhaust gas flow direction. Met.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the case of the flat plate-shaped catalyst body as in the above-mentioned conventional example, in order to collect the entire amount of the exhaust gas here and purify it by the catalytic reaction, a tubular flow path for guiding the exhaust gas to the catalyst body Since the structure must be installed side by side, and the catalyst body is located facing the exhaust port of the combustion chamber, the radiant heat radiated from the upstream surface of the catalyst body, which has the highest temperature, is reduced to the combustion chamber, This caused abnormal temperatures in the combustion chamber, causing problems such as flashback and runaway combustion.

In addition, when the amount of combustion in the combustion chamber temporarily increases and the fire spreads and comes into contact with the catalytic body, the combustion reaction is interrupted by the catalytic body, and carbon monoxide, odor, soot, etc. are generated. It was happening. In order to avoid this, when an exhaust gas mixing member such as punching metal is added to the upstream surface of the catalyst body, the mixing member is significantly heated and thermal reduction to the combustion chamber is further promoted, resulting in combustion abnormality. It was something that

Therefore, in reality, the catalyst body is set apart from the combustion section by a considerable distance, but the exhaust gas cannot be collected in total because of the pressure loss of the catalyst body and leaks to the peripheral release section with less resistance. Further, since the catalyst body is not sufficiently heated, there is a drawback that the purification performance is attenuated particularly when used in a state where the combustion amount is small, and exhaust gas cannot be completely purified in any case.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a combustion instrument including an exhaust gas purifying catalyst that is excellent in exhaust gas purifying performance and does not adversely affect the combustion chamber.

Means for Solving the Problems The technical means used in the present invention for solving the above-mentioned conventional problems is a tubular shape having a large number of communication holes downstream of the exhaust port of a combustion chamber and having a closed downstream end. The catalyst body is provided such that its cylinder inlet portion faces the exhaust port, and an exhaust gas mixing member is provided along the inner surface of the peripheral wall of the catalyst body or at the cylinder inlet portion of the catalyst body.

Action The present invention allows the catalyst body to form a flow path structure for guiding the exhaust gas into the inside of the catalyst body by the tubular shape in which the downstream end portion is closed, so that the catalyst body can be contacted without impairing the exhaust gas collecting ability. The medium can be installed at a considerable distance from the combustion chamber. Therefore, it is possible to reduce the radiant heat that the catalyst body returns to the combustion chamber, and it is possible to maintain the exhaust gas purification performance even when the combustion amount is small.

Embodiments Embodiments of the present invention will be described below with reference to FIGS. 1 to 9. In FIG. 2, reference numeral 1 is a box of the combustion apparatus, and the rear side of the combustion cylinder 2 provided in the central portion is surrounded by a reflection plate 3.
A glass tube 4 is arranged on the combustion tube 2, and a part of radiant heat from an internal red heat section (not shown) is transmitted therethrough, and a part is supplied to the outside by secondary radiation. An exhaust port 5 is opened above the combustion cylinder 2, and a cylindrical catalyst body 6 is vertically provided above the exhaust port 5.

The catalyst body 6 is formed by bending a honeycomb-shaped ceramic carrier containing silica and alumina as main components into a cylindrical shape,
An active component containing a white metal as a main component is supported on this, the inner diameter of which is larger than that of the exhaust port 5 and is positioned parallel to the opening method of the exhaust port 5, and the exhaust port 5 is provided on the side wall.
A large number of communication holes 7 are formed in a direction substantially perpendicular to the opening direction of the. Although FIG. 1 shows a cross section of the catalyst body 6,
The downstream end, that is, the upper end, is closely fixed to the top plate 8 that covers the upper portion of the combustion cylinder 2, and is in a closed state. On the other hand, the upstream end portion, that is, the lower end portion is opened to guide the exhaust gas discharged from the exhaust port 5. Near the inner wall of the catalyst body 6, an exhaust gas mixing member 9 made of a tubular expanded metal is provided in a substantially concentric manner.

Next, the operation will be described in detail. The fuel burns in the combustion cylinder 2, the inner wall surface is heated by the combustion heat, and a part of the radiant heat radiated from the heating wall surface passes through the glass cylinder 4 and a part thereof The cylinder 4 is heated and radiated and radiated again there, and diffused to the surroundings. On the other hand, untwisted components and carbon monoxide which have not been completely burned in the combustion tube 2 are discharged upward from the exhaust port 5 together with the heat which has not been recovered.

Here, the tubular catalyst body 6 is located above the exhaust port 5, and its downstream end is closed by the top plate 8. Therefore, as shown in FIG. 3, the tubular catalyst body 6 flows into the catalyst body 6. The exhaust gas (indicated by the arrow) gradually bends the flow path, and a part of the top plate 8
After being collided with, the flow path is refracted, passes through the communication hole 7 which is the only opening, and is discharged to the surroundings. Since the exhaust gas passage is completely covered with the tubular catalyst body 6, the entire amount of the exhaust gas surely passes through the communication hole 7, and the purification efficiency is remarkably enhanced.

Further, an exhaust gas mixing member 9 is attached near the inner wall of the catalyst body 6, and the exhaust gas collides there and is sufficiently mixed and then flows into the catalyst body 6. It is possible to carry out a complete oxidation action without causing a shortage.

In particular, even when the combustion amount becomes excessive in the combustion cylinder 2 and the flame is extended from the exhaust port 5, the oxygen-deficient portion at the flame center is mixed by the exhaust gas mixing member 9 and the catalyst body 6 is supplied with sufficient oxygen. Can be
Generation of carbon monoxide, odor, soot, etc. can be prevented.

On the other hand, in terms of heat, the catalyst body 6 which is the largest heat recovery / heat radiating body is positioned in the direction perpendicular to the combustion tube 2, and the exhaust gas mixing member 9 mounted inside the combustion tube 2 is also included. Are not opposed to each other, the radiant heat is emitted in a state of being dispersed more in the circumferential direction than in the direction directly below the combustion cylinder 2.

Therefore, the heat reduced from the catalytic body 6 toward the combustion tube 2 is significantly reduced, and a thermal adverse effect on combustion is caused, for example, runaway combustion due to excessive vaporization amount in the wick type, and overheating of the flame mouth portion in the premix type. Abnormal conditions such as flashback to the vaporization chamber can be prevented. Although there is some heat reduction from the top plate 8 and the reflection plate 3 etc., since these are made of metal plates, they have poor heat storage properties and heat is sequentially dissipated to the outside. Heat radiation to the can be almost avoided.

Thus, the combustible components in the exhaust gas are completely oxidized by the exhaust gas mixing member 9 into carbon dioxide and water, and most of the heat of the exhaust gas is recovered by the top plate 8, but most of it is the catalyst body. While passing through 6, the exhaust gas, which is collected and is clean and has a low temperature, is discharged. Since the entire amount of exhaust gas passes through the catalyst body 6, there is no leakage of harmful components as in the conventional case, and the heat radiated from the side wall of the catalyst body 6 heated by the heat retained by the exhaust gas or the combustion heat of unburned components is Either directly or after being reflected by the reflecting plate 3, they are supplied to the front and can be used for heating, heating, drying and the like.

The exhaust gas mixing member 9 is preferably made of a material having a small heat capacity and an excellent mixing effect of the exhaust gas, and in addition to the expanded metal as shown in FIG. 1, a wire mesh shown in FIG. 4 and a bunching metal shown in FIG. The metal perforated plate, or a metal plate or rod in which the rods are arranged in parallel as shown in FIG. 6 can be used. Further, the exhaust gas mixing member 9 can exert the above effect if it is provided only at a position where the exhaust gas directly collides with the catalyst body 6. Therefore, when the diameter of the catalyst body 6 is sufficiently large with respect to the exhaust gas passage, it is shown in FIG. As described above, by providing only the upper portion of the catalyst body 6, that is, the downstream side portion, the mixing action of the exhaust gas is sufficiently obtained, and the thermal reduction to the combustion cylinder 2 can be further reduced.

Further, in order to obtain the effect of mixing the exhaust gas, in addition to being mounted along the inside of the peripheral wall of the catalyst body 6 as described above, the central portion of the catalyst body 6 is at the cylinder inlet of the catalyst body 6 as shown in FIG. The exhaust gas mixing member 9 having the central hole 10 protruding inward may be provided, and the same effect can be obtained even if the exhaust gas is mixed before flowing into the inside of the catalyst body 6. In a normal combustion state, the mixing is almost completed at the position of the exhaust port 5, and it is necessary to promote mixing only when the flame extends, but when the flame extends, the temperature of the exhaust gas rises and the volume of the exhaust gas also increases. The number of channels increases and the flow channel expands. At this time, the exhaust gas mixing member 9 provided at the cylinder inlet of the catalyst body 6 works effectively,
Mixing can be promoted to prevent incomplete reaction. Here, the exhaust gas mixing member 9 has a central hole as shown in FIG.
The peripheral portion of 10 has a concavo-convex continuous structure, which causes turbulence in the flow of the exhaust gas, resulting in promotion of the mixing action.

In any of the above cases, the catalyst body 6 can use a braided body of heat-resistant fibers or the like in addition to the honeycomb ceramic carrier. In this case, the carrier is lightweight and highly flexible. Therefore, there is an advantage that it is strong against impact and can be easily processed into a cylindrical shape, a rectangular shape, or another shape. As the active component of the catalyst body 6, not only oxidative purification of unburned components and carbon monoxide, but also catalysts for purification, decomposition, reduction of nitrogen oxides (nox) and sulfur oxides (socks) are carried. However, the above effects can be sufficiently exhibited in any case as long as the purpose is to purify exhaust gas.

EFFECTS OF THE INVENTION As described above, according to the present invention, exhaust gas mixing in the upstream of the catalyst body is promoted, incomplete cleaning action due to partial concentration change of exhaust gas is eliminated, and complete purification action is performed. At the same time, it is possible to provide a combustion instrument with high radiation efficiency while preventing thermal adverse effects on the combustion section.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a combustion apparatus according to a first practical example of the present invention, FIG. 2 is an entire front view thereof, FIG. 3 is an explanatory view of its action, and FIGS. 4 to 7 are combustion of the same embodiment. A modified example of the exhaust gas mixing member in the apparatus, FIG. 8 is a sectional view of the main part of the combustion apparatus in the second embodiment, and FIG. 9 is a perspective view of the main part. 2 ... Combustion cylinder, 5 ... Exhaust port, 6 ... Catalyst body, 7 ... Communication hole, 9 ... Exhaust gas mixing member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masato Hosaka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-1-306704 (JP, A) Actual development Sho 56-13631 (JP, U) Actual opening Sho 55-114826 (JP, U) Actual opening Sho 55-114828 (JP, U) Actual opening 55-42102 (JP, Y2) Actual opening Sho 51-15869 (JP, Y2)

Claims (2)

[Claims] 1. A tubular catalyst body having a closed downstream end, in which a large number of communication holes are formed in a peripheral wall, is provided on a downstream side of an exhaust port of a combustion chamber so that a tubular inlet part faces the exhaust port. Moreover, an exhaust gas mixing member composed of a metal porous body such as a wire mesh, expanded metal, or punching metal is attached along the inner surface of the peripheral wall of the catalyst body. 2. A downstream side of the exhaust port of the combustion chamber is provided with a cylindrical catalyst body having a plurality of communication holes formed in the peripheral wall and having a closed downstream end so that the cylindrical inlet part faces the exhaust port. Further, a combustion apparatus is provided with an exhaust gas mixing member formed of a concavo-convex continuous body at a cylinder inlet portion of the catalyst body.