JPH01310217A - Combustion plate - Google Patents

Abstract

PURPOSE:To prevent instability of combustion, e.g. blow off, due to blow off even when high load combustion is made on fuel gas having a slow burning velocity and to enable increase of a combustion load by a method wherein burner ports are blinded at intervals of at least two burner ports or up to four burner ports. CONSTITUTION:In burner ports 11 formed in the shape of a lattice, large burner ports with a diameter of 1.5-2.0 millimeters are formed at intervals of a distance of 3.0-4.0 millimeters, and a blind part 12 where a burner port is formed is situated at intervals of three burner ports. When fuel-air mixture of combustion air and fuel gas is increased for high load combustion, the velocity of flow of the fuel-air mixture injected through the burner ports is increased to a value higher than a flame propagation speed. Flame F is blown up to cause the occurrence of blow off. However, since at the blind part 12, recirculation of combustion gas is produced as shown by an arrow mark, fuel-air mixture injected through the burner ports situated around the blind part 12 is continuously ignited by means of high temperature recirculation gas to perform stable combustion, and high load combustion being higher than that of a combustion plate having no blind part 12 can be achieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a heat-resistant plate such as a ceramic plate with a large number of flame holes,
This invention relates to a high-load combustion plate used as a tinder for combustion equipment.

[Prior Art] In this type of combustion plate, when the cross-sectional area of each flame hole is made constant, an unstable region of combustion occurs when the calorific value is varied over a wide range. In order to solve this problem, the flame hole is composed of a large flame hole and a medium flame hole with a cross-sectional area of about 1/2 that encloses the large flame hole.
It is known that combustion stability and combustion noise reduction can be achieved over a relatively wide range.

Further, Japanese Patent Publication No. 57-41648 describes an invention in which a combustion plate is applied to a gas burner in which flame holes with different opening areas are provided irregularly to reduce combustion noise.

Furthermore, Japanese Patent Publication No. 50-7125 discloses a burner plate that has flame holes of two or more different diameters alternately arranged in a symmetrical manner to make it possible to change the calorific value over a wide range and to improve the stability of combustion. is proposed.

However, the inventor discovered that when burning a fuel gas with a slow combustion rate such as propane or butane 13A under high load in a combustion device of all primary air combustion type (all premix type) using a combustion plate as a tinder, the combustion gas It has been found that generating recirculation is the most effective way to raise the upper limit of stable high-load combustion.

The purpose of the present invention is based on the above-mentioned knowledge, to prevent instability of combustion such as blow-off due to blow-off even when fuel gas with a slow combustion rate is burned under high load.
The object of the present invention is to provide a combustion plate that can increase the combustion load.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a combustion plate in which a heat-resistant plate having a predetermined shape is provided with a large number of flame holes penetrating the front and back sides in a lattice shape or a lattice shape. , 2 of the flame hole
We adopted a configuration in which the flame holes are blind at every fourth and every fourth.

Effects and Effects of the Invention] The combustion plate of the present invention has flame holes in a lattice shape or in a lattice shape.

In addition to providing a grid pattern, every second or more of the flame holes,
Every fourth or less flame hole is blind, so recirculation of combustion air occurs in the blind part of the flame hole, and even when fuel gas with a slow combustion rate is burned under high load, high-temperature The ignition of the mixture of fuel gas and combustion air by the recirculated combustion air is sustained, making higher-load combustion possible.

[Example] Next, the present invention will be explained based on a first example shown in FIGS. 1 and 2.

In this embodiment, the combustion plate 1 includes a ceramic plate 10 having a rectangular plane, and a large number of flame holes 11 penetrating the front and back sides.
are arranged in a grid (matrix). The flame hole 11 has a diameter of 3.0 to 4 large flame holes with a diameter of 1.5 to 2.0 mm.
．． They are formed at intervals of 0 mm, and every third blind part 12 has no flame holes.

As shown in Fig. 2, this combustion plate is used as a vent for a gas combustion device 2 of all primary air combustion type, and the fire 1]
Heat exchanger 11 installed above! ! Heat a container (not shown). As the fuel gas, in addition to 6C113A, which is city gas, fuel gases with high calorific values such as propane and butane are also used. In this case, when the supply amount of the mixture of combustion air and fuel gas is increased due to high-load combustion, the flow velocity of the mixture ejected from the flame hole becomes higher than the flame propagation velocity.
A so-called blow-off occurs in which the flame F blows up.

However, in the blind part 12 of the combustion plate, recirculation of combustion air occurs as shown by the arrow, so the air-fuel mixture ejected from the flame holes around the blind part 12 is continuously ignited by this high-temperature recirculated air. This results in stable combustion. As a result, higher high-load combustion can be achieved compared to a combustion device using a combustion plate without the blind portion 12.

If the area of the blind portions 12 is too large or the number thereof is too large, the proportion of the surface area of the combustion plate that does not contribute to combustion will increase, and the combustion load will be reduced on the contrary.

Also, if the area is too small or the number is too small, the above recirculation will be weak or the recirculation will be too small.

Since there are few areas where rings occur, the effect of preventing blow-off is weakened. Therefore, it is best to blind every two or more flame holes and every fourth or less flame holes.

The flame hole around the blind part 12 has a diameter of 1.2 to 1.2 degrees.
A medium long hole of about 4 mm or a diameter of 0.9 to 1.
It may be a small flame hole of about 1 mm.

3 and 5 show a second embodiment of the invention.

The combustion plate 3 is made of ceramic, and in this embodiment is constructed by providing a heat-resistant plate 30 having a rectangular planar shape with a large number of flame holes penetrating the front and back sides. The planar shape of the heat-resistant plate 30 can be selected as desired depending on the application, such as circular or triangular, and may be spherical, convex, or concave in addition to being flat.

This flame hole includes a large flame hole 31 with a diameter of 1.9 mm, a medium long hole 32 with a diameter of 1.3 mm, and a diameter of 1.0 mm.
It consists of three types of flame holes: small flame holes 33 of millimeter size. These three types of flame holes all have a circular shape, and the small flame holes 33 are arranged in a grid pattern. The large flame hole 31a is
Four small flame holes 33a, 33b, 33c, 33d located at equal intervals on a circle with a distance of 12.4 mm from the center.
Four medium elongated holes 3 located at equal intervals on concentric circles with a center-to-center distance of 3.4 mm
It is surrounded on four sides in the middle by 2a, 32b, 32c, and 32d. That is, four small flame holes 33a, 33b
, 33c, and 33d are the four medium elongated holes 32a, respectively.
It is arranged so as to be located between 32b, 32c, and 32d.

In this arrangement of flame holes, every other large flame hole 31 and four small flame holes 33 surrounding the large flame hole 31 are blind to form a blind portion 34. That is, there is a row in which small flame holes 33 are provided in a grid pattern, a medium elongated hole 32 is provided in the center of a square surrounded by four adjacent small flame holes 33, and a large flame hole 31 and a medium elongated hole in the center of the square. 32 are arranged alternately, and only every other large flame hole 31 is blind, and the four small flame holes 33 around it are blind.

This is a blind portion 34. Further, blind holes 3a are arranged in a row around the combustion plate 3 and at the mounting position of the ignition device to reduce thermal shock.

In addition, as in the modification shown in FIGS. 4A and 4B, the surface of the heat-resistant plate 30 has a conical, spherical, or cylindrical shape that includes all or half of the four small flame holes 33 around the large flame hole 31. If the recess 35 is provided, especially for propane with a slow burning speed, 13A
It is effective for flame stabilization of fuel gases such as (especially when the excess air ratio is high during low-load combustion), and can also reduce combustion noise during high-load combustion.

FIG. 5 shows a gas water heater 4 using combustion plates 3. Two combustion plates 3 are installed in parallel in the longitudinal direction, and air and fuel forcedly blown by a blower 41 are mixed. The gases are mixed in a mixing chamber 42 upstream of the plate 3, and ignited and combusted in a combustion chamber 43 on the first flow side of the plate 3. The heat generated by combustion is mainly absorbed by a heat exchanger consisting of water pipes 44 and fins 45, and is transferred to the flowing water in water pipes 44.

At this crater, the calorific value is 5.0OOkcal/hr
It is set so that it can be changed from 45,000 kcal/hr to 45,000 kcal/hr, and the amount of gas and air supplied is adjusted according to the calorific value. In this case, in the low calorific value region (30,0OOkcal/hr or more), the flame in the large flame hole 31 is stabilized by the small flame hole 33, and the medium elongated hole 32 is also stabilized in the same way, thereby stabilizing the entire flame group. is realized. Also, high calorific value region (5,0OOkcal/hr ~ 1
0,000 kCal/hr), the flames mainly in the medium elongated hole 32 and the large flame hole 31 become a dominant flame group and are stabilized.

In this case, the cross-sectional area ratio of each large, medium, and small flame hole is 4:2:
Grade 1 is most desirable.

In this gas water heater 4, in order to increase the flame stability of the large flame holes 31 during high-load combustion, if the small flame holes 33 are provided at a small pitch as flame-holding flame holes, the flame during low-load combustion Group stabilization can be measured. At this time, during high-load combustion, the large flame hole 31 and the medium long hole 32 become dominant in the flame group, and the stability of the flame group during high-load combustion is not impaired. If configured in a pattern, the combustion load will be extremely wide in °C.

Stable combustion can be ensured within the range, and destabilization of the flame hole group, which can cause abnormal combustion, can also be prevented.

In other words, the large flame hole is surrounded on four sides by small flame holes that provide good flame stability during low load combustion, is surrounded on four sides by medium flame holes that provide good flame stability during medium load combustion, and is surrounded on four sides by medium flame holes that provide good flame stability during high load combustion. Since the flame stability is essentially good, the flame stability is good over a wide range of changes in calorific value.

Furthermore, when using a fuel gas with a slow combustion speed such as propane or butane 13A, the jetting speed of the mixture of air and fuel gas from the flame hole becomes higher than the flame propagation speed during high-load combustion, which tends to cause blow-off. There is a flameless zone, which is made up of a large flame hole and the small flame holes around it, and this flameless zone forms a flame recirculation area and maintains the flame, allowing stable combustion.

FIG. 6 shows a third embodiment of the invention.

In this embodiment, the combustion plate 5 has a small flame hole 53 with a diameter of 1.0 mm in a heat-resistant plate 50, with a diameter of 3 to 4 mm.
A row of large flame holes 51 with a diameter of 1.5 mm is provided at the center of a square surface surrounded by four small flame holes 53, and a row of large flame holes 51 with a diameter of 1. . Rows of medium flame holes 52 of 3 mm are arranged alternately both vertically and horizontally, and only one large flame hole 51 is located at the intersection of the vertical and horizontal rows and columns. This arrangement, which forms a blind part 54 at every turn, enables extremely high-load combustion of fuel gases with high calorific values such as propane and butane in addition to city gas 6C113A. . In this embodiment, a small flame hole 53 is provided instead of the medium flame hole 52, and a large flame hole 51 is provided.
A similar effect can be obtained by setting the diameter to 1.6 millimeters.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a combustion plate showing a first embodiment of the present invention, and FIG.
Figure 3 is a plan view of a combustion plate showing a second embodiment of the present invention; Figure 4A is an enlarged view of a modified example; is a sectional view taken along the line C-C, and FIG. 5 shows the combustion. FIG. 6 is a schematic sectional view of a fully primary air combustion type gas water heater using a combustion plate as a nozzle, and FIG. 6 is a plan view of a combustion plate showing a third embodiment of the present invention. In the figure 1.3.5... Combustion plate 2- All primary air combustion type gas combustion equipment 4... Gas water heater 11... Flame hole 12.34.54... Blind part 31.51・
Large flame hole 32.52...Medium flame hole 33.53...Small flame hole Representative Patent attorney Ken Ishiguro Three tubes 1 Figure 47.・・′

Claims (1)

[Scope of Claims] 1) A combustion plate in which a heat-resistant plate having a predetermined shape is provided with a large number of flame holes penetrating the front and back in a lattice shape or a zigzag lattice shape, including every second or more flame holes, or every four flame holes. A combustion plate characterized by blind flame holes below the arbor. 2) A large number of large flame holes and small flame holes, or a large flame hole, a medium flame hole, and a small flame hole, penetrating the front and back sides of a heat-resistant plate having a predetermined shape,
In each combustion plate, which is provided in a lattice shape or a chidori lattice shape in a predetermined pattern, only the large flame holes are connected to two of the large flame holes.
A combustion plate characterized by having blinds at every third or more and every fourth or less. 3) In the combustion plate, which is a heat-resistant plate with a predetermined shape and has three types of cross-sectional areas, large, medium and small, and has many flame holes penetrating the front and back, the small flame holes are arranged in a lattice pattern to create a large flame. a first pattern band in which the hole is located at the center of the small flame hole, and each of the small flame holes is set in the middle of two adjacent medium flame holes arranged in a band shape; One pattern band was shifted by half a pitch in the large flame hole, and the patterns were arranged in a band shape, and a second pattern band in which the large flame hole and the small flame holes around it were blind were arranged alternately every other pattern. combustion plate. 4) In a combustion plate made of a heat-resistant plate with a predetermined shape and a large number of flame holes that penetrate through the front and back sides and have three types of cross-sectional areas: large, medium, and small, small flame holes are provided in a lattice pattern and adjacent to each other. A row in which a large flame hole is provided in the center of a square surrounded by four small flame holes, and a row in which a large flame hole and a medium flame hole are alternately provided in the center of the square are arranged alternately in both vertical and horizontal directions, A combustion plate characterized in that every other large flame hole is blind at a position where a vertical row and a horizontal row intersect.