JPH0627566B2 - Thin-film flame-type combustion equipment using flame holding plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention uses a thin film flame burner for performing a stratified combustion of a premixture of a fuel gas and air necessary for burning the gas into a thin film. It was about the burning equipment.

[Prior Art] In the Japanese Patent Application No. 63-38396, the applicant of the present invention has a flat or flat surface which blocks the jet flow at a predetermined distance from the jet port of a burner which jets a premixed gas of fuel gas and air. Combustion device using a thin-film flame burner for arranging a shut-off plate close to, and heading to the shut-off plate in the stagnation flow region of the jet flow, and performing stratified combustion of a premixture flowing along the shut-off plate into a thin-film flame Is proposed.

This gas combustion device had the following features.

a) It can be easily applied to cooking by using the blocking plate as a heated object, and heating by using the blocking plate as a radiant heat source,
It can be used for applications such as heating.

b) Since the combustion flame can be made thin and flat over a large area, the object to be heated can be heated uniformly.

c) Since stable combustion can be performed even in a region where the excess air ratio is large, the combustion temperature is low, and nitrogen oxides (N
Generation of Ox) is small.

d) Since a flat and thin premixed flame can be formed in a large area close to the object to be heated, the thermal efficiency is high.

[Problems to be Solved by the Invention] However, in the gas combustion device using the thin film flame, the formation of the thin film flame and the flow velocity of the premixed gas are maintained within a delicate balance range. Therefore, in the thin film flame formation region,
If the jet flow of the premixed air becomes non-uniform, the thin film flame fluctuates and is not stable. As a result, deterioration of combustibility and reduction of combustion efficiency occur.

An object of claim 1 of the present invention is to provide a thin-film flame-type combustion apparatus capable of increasing the combustibility and stability of a thin-film flame.

An object of claims 2 and 3 of the present invention is to provide a thin-film flame-type combustor, which has a high-grade appearance because the barrier plate is transparent or semi-transparent, and can be easily visually recognized whether or not it is burning. is there.

[Means for Solving the Problems] To achieve the above object, the present invention employs the following configurations.

(1) A blocking plate that blocks the jet flow is placed at a predetermined distance from the jet outlet of the burner that jets the premixed mixture of fuel gas and combustion air, and the pre-stagnation region of the jet flow In a combustion device for stratified combustion of an air-fuel mixture into a thin film flame, an annular flame holding plate portion, and a flame holding plate having an upward edge rising from the outer periphery of the flame holding plate portion, the flame holding plate portion of the ejection port It was arranged so as to be substantially flush with the jet surface around the periphery.

(2) In the configuration of (1) above, the blocking plate is formed of a transparent or semi-transparent glass plate or a ceramic plate, and the upward edge of the flame holding plate is closer to the outer peripheral edge of the blocking plate. An annular ridge made of a heat-resistant material is provided on the upper surface of the outer periphery of the flame holding plate located inside.

(3) With the configuration of (1) above, the blocking plate is formed of a transparent or translucent glass plate or a ceramic plate, and a porous ceramic plate is fixed to the lower surface of the blocking plate.

[Operation and Effect of the Invention] (Regarding Claim 1) By adopting the flame holding plate, the following operation and effect can be obtained.

(A) Since the outer peripheral edge of the thin film flame adheres to the flame holding plate portion, the stability and combustibility of the thin film flame can be improved.

That is, in the case where there is no flame holding plate, the thin film flame has a premixed gas that diffuses into the outer peripheral portion of the thin film flame, and the fuel becomes leaner than the combustible air-fuel ratio. The fuel gas is discharged unburned.

The flame holding plate portion prevents the premixed air from diffusing into the outside air at the outer peripheral edge portion of the thin film flame, and eliminates such inconvenience. The upward edge prevents the entry of wind or the like to protect the outer peripheral edge of the thin film flame from the influence of the outside air.

(B) Since the thin film flame is held between the blocking plate and the flame holding plate portion, the stability of the thin film flame can be improved against the disturbance of the atmosphere such as a gust of wind.

(C) The flame holding plate reflects the heat generated by the thin film combustion and supplies a large amount of radiant heat to the blocking plate, so that the blocking plate is efficiently heated.

(Claims 2 and 3) The barrier plate is made of a transparent or translucent glass plate or a ceramic plate, and the upward edge of the flame holding plate is located inward of the outer peripheral edge of the barrier plate. By providing a ring-shaped ridge made of a heat-resistant material on the outer peripheral upper surface of the flame plate portion, or by arranging a porous ceramic plate on the lower surface of the blocking plate, the following operational effects are achieved.

(D) Since the blocking plate 4 is transparent or semi-transparent and has no protrusions such as Gotoku and is flat, it is possible to obtain a combustion device having a high-grade appearance.

(E) Since the thin film flame is an all-primary air combustion flame and is thin, it emits less visible light, and it is difficult to determine whether combustion is in progress or combustion is stopped based on the presence or absence of the flame. However, since the annular ridge made of heat-resistant material or the porous ceramic plate is heated to emit a large amount of visible light, it is easy to determine whether the burner is burning.

[Embodiment] Next, the present invention will be described based on an embodiment shown in FIGS.

FIG. 1 shows a thin-film flame type gas combustion apparatus (gas stove in this embodiment) according to the present invention, and 100 is its case, which has a flat box shape. Top plate 1 of case 100
01 is provided with a round hole 102 in the center, and the round hole 102
An annular juice tray 110 is fitted into the inner peripheral portion of the. The soup saucer 110 includes a bottom plate portion 111, an outer peripheral cylinder portion 112,
It comprises a brim-shaped eaves portion 113 extended to the upper end and an inner peripheral cylindrical portion 114 extending from the inner periphery of the bottom plate portion. Soup saucer 110
A cylindrical partition wall 120 for partitioning the burner installation chamber from the inside of another case is provided coaxially with the round hole 102 and is fixed to a case bottom plate 104 having a ventilation hole 103 below. .

Reference numeral 1 denotes an all-premixed combustion (all primary air) type burner using a combustion plate, and a case 10 that is coaxial with the round hole 102.
It is installed vertically within 0. The burner 1 is formed by covering the upper surface of a cylindrical metal burner body 11 having a bottom and an open upper surface with a combustion plate 2. Reference numeral 3 denotes a premixed gas supply device, which supplies the burner 1 with a premixed gas of fuel gas and combustion-required air. 4 is above the burner 1 and above the combustion plate 2
Is a circular glass blocking plate arranged in parallel with (orthogonal to the axis of the burner), and its lower surface is a blocking surface 4A. The burner 1, the premixed air supply device 3 and the shut-off plate 4 constitute a thin film flame burner.

The combustion plate 2 has a circular small hole 22 having a diameter of 1.0 to 2.5 mm and a diameter of 3.0 to 6 on the entire surface of the ceramic plate 21 mainly composed of cordierite and having excellent thermal shock resistance except the outer peripheral edge portion. .0
It is formed in a grid pattern with mm intervals.

In this embodiment, the upper end of the burner body 11 is expanded to form a flange-shaped portion 12, and the tip thereof is extended in the axial direction to provide a large-diameter cylindrical portion 13. A heat-resistant metal ring 14 having an upper end bent outward is externally fitted to the large-diameter cylindrical portion 13, and the combustion plate 2 is placed on the flange-shaped portion 12 and fitted into the large-diameter cylindrical portion 13. ing.

The flame holding plate 5 includes an annular flame holding plate portion 51, an upward edge portion 52 rising from the outer periphery of the flame holding plate portion 51, and a holding plate portion 53, and is welded to the heat resistant metal ring 14.

The flame holding plate portion 51 is substantially flush with the upper surface 2A which is the jet outlet surface of the combustion plate 2, spreads on the outer periphery of the upper surface 2A, and is arranged around the injection port so as to be flush with the jet surface.

The holding plate portion 53 extends to the inner circumference of the flame holding plate portion 52 and holds the upper surface of the outer peripheral edge portion of the combustion plate 2.

The upper surface of the outer peripheral edge of the combustion plate 2 is edged so that the upper surface of the flame holding plate 5 and the upper surface of the combustion plate 2 are flat and continuous without a step. The upper surface of the flame holding plate portion 51 is the flame holding surface 5.
A, and a narrow gap 5B is provided between the outer periphery of the flame holding plate 5 and the inner peripheral cylindrical portion 114 of the juice receiving tray.

The premixed gas supply device 3 has an upstream connected to a blower port of a blower and a downstream connected to a supply port of a fuel gas supply pipe 32 in a mixing pipe 31 connected to the burner body 11. The inside of the burner body 11 is a premixed air chamber.

The blocking plate 4 is composed of a circular heat-resistant glass plate 41 having a thickness of 3 to 12 mm and a diameter of 120 to 200 mm, a metal ring 42 wound around the outer periphery thereof, and legs 43 fixed to the metal ring 42 at three positions. Become. The glass plate 41 used is colorless or colored and is transparent or translucent. The blocking plate 4 is formed such that the lower ends of the legs 43 are inserted and fixed in the holes formed in the bottom plate portion 111 of the juice tray, and the distance between the blocking surface 4A and the upper surface 2A of the combustion plate becomes a set value. Has been done.

Next, the operation of the thin film flame type gas combustion equipment according to this embodiment will be described.

The fuel gas is mixed with the air forcibly supplied from the blower so that the air is somewhat in excess of the stoichiometric air-fuel ratio, and the mixing pipe 3
At 1, the mixture is uniformly mixed and supplied to the mixture chamber. When the ignition device provided in the vicinity of the burner is operated at the same time, the premixed gas ejected from the small holes of the combustion plate is ignited.

[When heat generation amount is large] The small jets from the small holes 22 are faster than the flame propagation speed, and the small jets spread in the horizontal direction to widen the cross-sectional area of the basin and contact each other, and are almost parallel to each other. It becomes a large jet with a large area. The flow velocity of this large jet in the direction of the blocking surface gradually decreases,
It becomes zero at the blocking surface 4A. The large jet is deflected by the blocking plate 4 and spreads radially along the blocking plate 4. The jet flow that spreads radially becomes slower because the cross-sectional area of the flow passage increases as the distance from the center increases.

When ignited in this state, the flame propagation speed S of the premixed air,
Velocity of large jet (composite velocity of intercepting surface and radial direction) V
A thin-film combustion flame is formed on the mating surface. It has been confirmed by a number of experiments by the present inventor that the thin film flame F is substantially circular and has an area slightly larger than that of the combustion plate 2. The outer peripheral edge of the thin film flame F is
Due to the action of the boundary layer generated in the premixed air flowing along the flame holding surface 5A, the flow velocity of the large jet spreading radially becomes small near the flame holding surface, so that the curved surface is curved toward the flame holding surface and the edges are flame held. It becomes attached to the surface. Further, in the combustion flame F, the flame propagation speed S becomes large because the jet speed of the small jet increases (the combustion amount increases) or the air-fuel ratio of the premixed air becomes lean (excessive combustion air). When it is lowered, it is displaced toward the blocking plate 4 as in F1 and the area is increased, and when it is reduced, it is displaced toward the combustion plate 2 as in F2 and the area is reduced. That is, the large jet flow velocity V> S (flame propagation velocity)
As long as the above, there is always a surface having a large jet flow velocity V = S (flame propagation speed) between the upper surface 2A of the combustion plate 2 and the cutoff surface 4A, so misfiring due to blowout is unlikely to occur.

As described above, in this combustion device, the formation position and size of the thin-film combustion flame F change only slightly with respect to changes in the combustion amount, changes in the excess air ratio, or changes in the oxygen concentration in the air. And the combustion itself is extremely stable.

Thereby, the stability and combustibility of the thin film flame F can be improved. That is, without the flame holding plate 5, the thin film flame F
Is a non-combustible air-fuel ratio in which the fuel is leaner than the combustible air-fuel ratio, the outer peripheral edge of the thin film flame F is shaken, and a small amount of fuel gas is discharged unburned. To be done. As described above, the flame holding plate 5 adheres the outer peripheral edge of the thin film flame F to the surface of the flame holding plate 5 to prevent the mixing of the outside air, so that such inconvenience is eliminated.

Furthermore, since the thin film flame F is held between the blocking surface 4A and the flame holding surface 5A, stability can be improved against atmospheric disturbance such as gusts of wind, and heat rays generated by combustion are reflected on the flame holding surface 5A. By doing so, a large amount of radiant heat can be supplied to the blocking surface 4A, and the blocking surface 4A can be efficiently heated. Therefore, when the object to be heated is placed on the blocking plate 4 or the radiant heat is used for heating or drying, the efficiency is improved.

In this embodiment, the ventilation hole 103, the burner installation chamber A, the outer periphery of the flame holding plate 5 and the inner peripheral cylindrical portion 11 of the soup saucer.
An air flow (arrow K) due to natural convection that cools the flame holding plate 5 is generated through a narrow gap 5B between the flame holding plate 5 and the frame 4.

[When the calorific value is small] As shown in FIG. 2, a small flame f that adheres to each small hole and burns
The surface of the combustion plate 2 becomes red like the all-primary-air infrared burner using a ceramic plate (combustion plate) having many ordinary small holes. It is well known that this burner burns stably.

The transition from this burner to a thin film flame burner is the combustion amount,
That is, it is performed reversibly and stably with a change in the supply amount of the premixed gas. As a result, the diameter of the combustion plate 2 is 65
In case of mm, the calorific value is 400 kcal / h ~ 4000 k
It can be changed up to cal / h. This maximum calorific value is the ratio of the minimum calorific value (generally called the Derntown ratio)
Is a value sufficient to use this burner as a cooking heat source such as a stove, a heating heat source such as a stove, or a heating source such as a water heater.

Further, the thin-film combustion flame F is stable in combustion even in a state in which the air is sufficiently in excess of the stoichiometric air-fuel ratio, so that combustion with excessive combustion air is possible and a large amount of heat is dissipated by radiation, so that the combustion temperature is It can be made low and the generation of nitrogen oxides is small.

Furthermore, since a thin film combustion flame F capable of dissipating a large amount of heat due to radiation can be formed in a wide area close to the blocking plate 4, when the blocking plate 4 is an object to be heated, high heating efficiency can be obtained.

When the jet flow is a laminar flow, the thin-film combustion flame F has a sharp thin-film shape, but the shape is slightly unclear in the transition region from laminar flow to turbulent flow, and thick with vortex in the turbulent flow region. Spread as a layer. Therefore, the combustion device using the thin film combustion flame F of the present invention exerts a sufficient effect only in the laminar flow region of the jet flow.

FIG. 3 shows another embodiment.

In this embodiment, the flame holding plate 5 has a diameter smaller than that of the blocking surface 4A and is provided with a ring-shaped ridge 6 made of a heat-resistant material on the outer circumference, or a porous ceramic plate 7 is fixed to the blocking surface 4A.

The annular protrusion 6 is formed by adhering a ring made of glass cotton or ceramic cotton, and a honeycomb ceramic sintered body is preferably used for the porous ceramic plate 7.

The annular projection 6 and the porous ceramic plate 7 are both heated by a thin film flame to emit a large amount of red visible light,
It functions so that it can be visually recognized that it is burning.

The present invention includes the following modes in addition to the above-described embodiments.

A) The blocking plate 4 and the flame holding plate 5 may be a porous body having some air permeability like a porous ceramic plate.

B) The blocking plate 4 and the flame holding plate 5 may be arranged so as to be slightly inclined with respect to the axis, and may be a curved surface having a large radius of curvature or an obtuse conical surface.

C) The combustion plate 2 may be a regular polygon such as a square, or may be made of heat-resistant metal.

D) The premixed gas ejected from each of the small holes 22 of the combustion plate may be a premixed gas whose primary air is somewhat smaller than the theoretical air-fuel ratio, in addition to the total premixed gas having an excess air ratio of 1 or more.

E) The burner may be a nozzle whose cross-sectional area gradually decreases toward the tip, and the tip of this nozzle is provided with a perforated baffle plate such as a mesh or a honeycomb, or of a multiple structure arranged coaxially. It may be a burner having a nozzle.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a thin film flame type gas combustion device according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the combustion part thereof.
FIG. 3 is a cross-sectional view of a main part of a thin-film flame combustion device of another embodiment, FIG. 4 is an overall perspective view showing the assembly of the burner portion excluding the juice pan, and FIG. 5 is an overall perspective view. In the figure, 1 ... All premixed combustion (all primary air) type burner using combustion plate, 2 ... Combustion plate, 3 ... Premixed gas supply device, 4 ... Blocking plate, 4A ... Blocking surface, 5 ...... Flame holding plate, 5
A ... Flame holding surface, 6 ... Annular ridge, 7 ... Porous ceramic plate, F, F1, F2 ... Thin film flame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Ishikawa 2-26 Fukuzumi-cho, Nakagawa-ku, Nagoya, Aichi Prefecture Linnai Co., Ltd. (72) Inventor Shunichi Oshida 507-2, Takaracho, Tokai City, Aichi Prefecture Toho Gas Co., Ltd. Inside Research Institute, Institute of Technology (72) Inoue Chiyomi, 507-2, Takaracho, Tokai City Gas Technology Co., Ltd., Research Institute of Technology (56) Reference JP-A-1-310214 (JP, A) Actual development Sho-53-56139 (JP, U)

Claims (3)

[Claims] 1. A position separated from a jet port of a burner for jetting a premixed mixture of fuel gas and combustion air by a predetermined distance,
In a combustion device that arranges a shutoff plate that shuts off the jet flow and stratifies the premixed mixture into a thin film flame in the stagnation flow region of the jet flow, the annular flame stabilizer plate and the outer circumference of the flame stabilizer plate A thin film flame type using a flame holding plate, characterized in that the flame holding plate having a facing edge portion is arranged so that the flame holding plate portion is substantially flush with the ejection port surface around the ejection port. Combustion equipment. 2. The thin-film flame combustion device according to claim 1, wherein the blocking plate is formed of a transparent or translucent glass plate or a ceramic plate, and an upper edge portion of the flame holding plate is the blocking plate. A ring-shaped ridge made of a heat-resistant material is provided on the upper surface of the outer periphery of the flame holding plate portion, which is located inward of the outer peripheral edge of 3. The thin film flame type combustion apparatus using the flame stabilizing plate according to claim 1, wherein the blocking plate is formed of a transparent or translucent glass plate or a ceramic plate, and a bottom surface of the blocking plate is provided. The porous ceramic plate was fixed.