JPS632755Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an incomplete combustion detection device for indoor open type combustion equipment.In particular, it accurately detects incomplete combustion in the main burner itself, and also detects incomplete combustion in the main burner and incomplete combustion detection tube. The purpose is to make it easier to ignite.

If the fuel supply is normal, there are three possible causes of incomplete combustion in combustion equipment:

(1) Caused by a decrease in indoor oxygen concentration.

(2) Caused by a lack of primary air due to dust clogging in the primary air hole of the main burner.

(3) Causes due to lack of secondary air due to clogging of the exhaust section, such as clogging of heat exchanger fins.

As a countermeasure for the drop in oxygen concentration mentioned in (1) above, there is a pilot burner for detecting a drop in oxygen concentration, which utilizes the rise of flame when the oxygen concentration drops.
It has no effect on the primary air shortage in the main burner (2), and cannot be detected against the secondary air shortage (3) unless the oxygen concentration around the pilot burner decreases. Therefore, for the secondary air shortage mentioned in (3) above, there is a method that uses the pressure inside the combustion chamber caused by the clogging of the heat exchanger fins to guide contaminated air to the vicinity of the pilot burner, or a There are some methods that take advantage of the overflow of the main burner's flame and install a pilot burner in the position where the main burner's flame overflows, but in either case, it is a secondary detection and is subject to accuracy.

As described above, as a means to deal with all of the above three types of causes, it is necessary to monitor the main burner itself. As such means, the first
There is a conventional example as shown in the figure. FIG. 1 shows an elongated main burner 1 with an incomplete combustion detection tube 2 attached thereto, FIG. 1A is a top view, and FIG. 2B is a side view. 3 is a temperature sensing element, 4 is an air hole for secondary air control, 5 is a nozzle holder, and 6 is a nozzle from which gas is ejected, sucks primary air, enters main burner 1, and crosses in the longitudinal direction. A flame is formed in the flame hole section 7 consisting of a large number of flame holes 7a. The incomplete combustion detection tube 2 is attached so as to share a part of this flame hole portion 7. 8 is a gas supply pipe. This incomplete combustion detection tube 2 applies the principle of a so-called separate flame burner, and as the incomplete combustion detection tube 2, the primary flame is formed in a part of the burner flame hole 7, and the primary air is formed in the main burner 1. The primary air enters from the primary air suction portion 1a, and gas is also supplied from the nozzle 6. Therefore, the primary flames of the main burner 1 and the incomplete combustion detection tube 2 are formed with the same gas-air mixture ratio. On the other hand, in the main burner, sufficient secondary air can be taken in from the surroundings, but in the incomplete combustion detection tube 2, the air hole 4 for secondary air control
Under normal conditions, a primary flame is formed at the base of the incomplete combustion detection tube 2, but when the oxygen concentration decreases,
The amount of secondary air is controlled so that the primary flame of the main burner 1 blows off from the base of the incomplete combustion detection tube 2 before it blows off or lifts and generates CO.

Therefore, an extreme temperature change can be applied to the temperature sensing element 3 attached to the center of the incomplete combustion detection tube 2 when the oxygen concentration decreases. Such devices can cause incomplete combustion due to the three types of causes mentioned earlier: a decrease in the oxygen concentration in the room, a lack of primary air due to a blockage in the primary air intake section of the main burner, and a secondary cause due to a blockage in the fins of the heat exchanger. It can deal with all air shortages. Although the conventional example shown in FIG. 1 is excellent as described above, the following two improvements can be made to this device.

(1) It is less sensitive to clogging of the primary air intake section of the main burner than when the oxygen concentration drops.

(2) Ignition must be done at the top of the incomplete combustion detection tube 2, and two igniters are required unless there is a flame transfer hole.

The reason for (1) above will be explained with reference to FIG. Figure 2 shows the combustion characteristics when the oxygen concentration decreases.
The vertical axis shows the air-fuel mixture injection speed, and the horizontal axis shows the equivalence ratio, which is a dimensionless quantity shown below.

Equivalence ratio = mass of oxidizer/mass of fuel/(mass of oxidizer/mass of fuel) The stoichiometric mixture ratio a is the combustion set point, b is the blow-off limit line by secondary air control, and c is the blow-off and lift limit line. It is. When the oxygen concentration decreases due to indoor air pollution, etc., a, b, and c move in the direction of the arrows, and when a and b intersect, the primary flame blows off from the base of the incomplete combustion detection tube. I will do it.

However, when the main burner is clogged, a and c move in the direction of the arrow, but the secondary air itself remains unchanged, so the limit line of b does not change. Therefore, since the distance between a and b becomes wider, it becomes less sensitive to lack of air.

The present invention is intended to compensate for these drawbacks, and one embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is an example of a configuration diagram of the incomplete combustion detection device, with FIG. 3A being a top view and FIG. 3B being a side view. That is, the incomplete combustion detection tube 2 is attached to a part of the main burner 1 except for both ends, which has a burner flame hole part 7 on the upper surface consisting of a large number of slit-shaped flame holes 7a intersecting in the longitudinal direction. . 3 is a temperature sensing element facing inside the incomplete combustion detection tube 2; 4 is an air hole for secondary air control provided in the lower part of the incomplete combustion detection tube 2 facing the burner flame hole 7 side; 7
It is provided close to the flame a and also serves as a flame transfer hole from the flame hole 7a to the slit-shaped flame hole 9a of the main burner 1 located below the incomplete combustion detection tube 2. 5 is a nozzle holder, 6 is a nozzle, and 8 is a gas supply pipe. FIG. 4 is an enlarged perspective view of the incomplete combustion detection tube 2, and the slit-shaped flame hole 9a is located below the incomplete combustion detection tube 2 as described above.
Moreover, it is arranged so as to intersect with the flame hole 7a. 9
Reference numeral b indicates a flame for transferring heat, and reference numeral 10 indicates a secondary air control flame located close to the incomplete combustion detection tube 2.

The incomplete combustion detection device according to the present invention applies the principle of a so-called separate flame burner, and can deal with all causes of incomplete combustion as described in the conventional example. Here, we will explain the newly added effects. As shown in FIG. 4, the air hole 4 for secondary air control is
0. Therefore, secondary air is supplied into the incomplete combustion detection tube 2 from between the air hole 4 and the secondary air control flame 10 adjacent thereto. However, the primary air intake section 1 of the main burner 1
If blockage a occurs, the amount of primary air decreases, causing the adjacent secondary air control flame 10 to expand significantly, and as a result, from the air hole 4 into the incomplete combustion detection tube 2. This limits the amount of secondary air flowing in.

As a result, as shown in FIG. 2, the combustion setting a and the blow-off limit line b due to secondary air control move in the directions of the arrows. In general, taking into account gas pressure fluctuations, test gas problems, and variations during mass production, a and b are kept as far apart as possible during normal operation, and a and b react sensitively during incomplete combustion. It is desirable that they be close to each other. The mounting position of the incomplete combustion detection tube 2 relative to the main burner 1 is determined in order to avoid the flame holes 7a at both ends of the burner flame hole portion 7 where the flame tends to blow out, and to ensure secondary air control during incomplete combustion. Incomplete combustion detector tube 2
A flame 10 for controlling secondary air can be present next to the flame 10 for controlling secondary air.

In addition, the air hole 4 for secondary air control also serves as a flame transfer hole, and a slit-shaped flame hole 9a is provided at the bottom of the air hole 4 so as to intersect with the flame hole 7a. When igniting, there is no need to ignite at the top of the incomplete combustion detection tube 2, and the flame can easily transfer to the flame inside the incomplete combustion detection tube 2, even when the main burner is ignited with a conventional pilot burner. Even in the case of direct ignition, it becomes possible to ignite with one igniter.

As described above, the present invention uses an incomplete combustion detection tube to separate the flame, and when incomplete combustion occurs, the air hole through which secondary air flows into the detection tube is blocked by a secondary air control flame. This makes it easy to detect incomplete combustion, and during normal conditions, the incomplete combustion detection cylinder can be used to transfer fire through its air holes.

[Brief explanation of drawings]

Figures 1A and B are top and side views of a main burner equipped with a conventional incomplete combustion detection device, Figure 2 is a combustion characteristic diagram when the oxygen concentration decreases, and Figures 3A and B are the present invention. FIG. 4 is a top view, a side view, and an enlarged perspective view of an incomplete combustion detection tube of the incomplete combustion detection device in one embodiment. 2... Incomplete combustion detection tube, 3... Temperature sensing element (detection element), 4... Air hole, 7... Burner flame hole section,
7a...flame hole, 9a...slit-like flame hole.

Claims (1)

[Scope of utility model registration request] An incomplete combustion detection tube is installed in a part of the burner flame hole section, which has a large number of flame holes, except for both ends, and a secondary combustion detection tube that also serves as a flame transfer hole is provided at the lower part of the incomplete combustion detection tube facing the burner flame hole side. An air hole for air control is provided close to the flame in the burner flame hole portion, and the flame hole located below the incomplete combustion detection tube is formed into a slit-shaped flame hole that intersects with other flame holes. , an incomplete combustion detection device including a detection element for detecting temperature in the incomplete combustion detection cylinder;