JPH045883Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application and overview of the invention] The present invention relates to a flashback safety device, particularly a flashback safety device for a forced combustion device. By adapting the flame detection section of the misfire safety device to the tendency of gas richness caused by uneven supply air from the air supply fan, it is possible to reliably detect flashback conditions in a wide combustion range. It is something.

[Prior art and its problems] Among forced air supply and exhaust type combustion devices, especially in the case of the forced combustion type shown in Fig. 4, the combustion chamber is in a closed state (only the exhaust side is open and the surrounding area is closed). surrounded by walls). In the case of such combustion equipment, flashback from the combustion surface can lead to overheating of the appliance, so conventional methods have been used to detect flashback on the combustion surface and detect when flashback occurs. , the gas circuit is shut off.

For this reason, in conventional combustion devices, a flame rod-type misfire safety device detection section or a thermocouple-type misfire safety device detection section is installed in a part of the planar flame hole 10 formed at the bottom of the combustion chamber 1. 20 are arranged. The detection unit 20 outputs a predetermined output signal to operate a safety device when a sufficient flame is not formed on the detection target or when the flame is completely extinguished. Therefore, as described above, when a flashback condition occurs, the misfire safety device is activated by the disappearance of the flame or the decrease in temperature, and subsequent flashback combustion is prevented.

However, with a configuration in which the detection section of the misfire safety device is simply disposed in a part of the flame hole section 10, it may not be possible to reliably detect a flashback condition.

This is because when the area of the flame hole portion 10 is large, even if a flashback phenomenon occurs in a part of the flame hole portion 10, the flashback phenomenon may not occur in other parts.
In such a case, if the detection part of the misfire safety device is installed in a part where no backfire phenomenon is occurring, even though the flashback phenomenon is occurring in other parts,
This is because the misfire safety device will not operate.

The present invention is designed so that gas and combustion air are fed into a relatively wide approximately rectangular flame hole portion 10 formed at the bottom of the combustion chamber 1 by a forced air supply fan, and the flame hole portion 10 is In the case where a flashback phenomenon occurs only in a part of the flame hole part 10, Flame hole part 1
It is an object of the present invention to ensure that a misfire safety device operates reliably even when a flashback phenomenon occurs in a part of the engine.

[Means for solving the problems] In order to solve the above problems of the present invention, the means are as follows:
``The detection unit 20 is disposed on the side that becomes gas rich due to the characteristics of the air supply fan 3.''

[Operation] The above technical means of the present invention operates as follows.

In the case where a mixture of gas and air is supplied to the flame hole part 10 by the fan 3, the mixing ratio of the gas and air is not constant depending on the air suction direction of the fan 3 and the relationship with the blades of the fan 3. However, in this type of combustion device, flashback always occurs first on the gas-rich side.

In the above technical means, since the detection section 20 of the misfire safety device is disposed on the side where the gas is rich, the backfire phenomenon occurs first on the side where the detection section 20 is disposed.

[Effects] Since the present invention has the above configuration, it has the following unique effects.

Since the flashback phenomenon occurs first from the part where the detection section 20 of the misfire safety device is installed, the flashback phenomenon can be reliably detected even if the flame hole section 10 is wide, and when the flashback phenomenon occurs, The misfire safety device can stop combustion, improving safety.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

The combustion device of this embodiment is a forced air supply/exhaust type combustion device used in water heaters, etc. As shown in FIG. 10, and a discharge port 31 of the fan 3 is connected to the bottom of a cavity 12 formed below the flame hole section 10.

The flame hole portion 10 has a rectangular planar shape, and a baffle plate 13 is inserted into the cavity 12 below the flame hole portion 10 to make the pressure distribution of the air-fuel mixture discharged from the discharge port 31 uniform. ing.

As shown in FIG. 2, the fan 3 has blades 32 attached to the drive shaft of a motor M and is housed in a casing 33 of the fan 3. Gas is supplied from a gas supply connected to the peripheral wall of the casing 33. It is designed to be supplied into the casing 33 from the pipe G. Then, the output valve 21 of the misfire safety device 2 is inserted into the circuit of the gas supply pipe G together with a control valve etc. for controlling gas supply, and when the appliance starts operating,
This output valve 21 is opened and gas supply is started.

In the configuration described above, combustion air is sucked from the center of the casing 33 and supplied to the empty chamber 12 from the discharge port 31.
As shown in FIG. 2, the gas concentration distribution in the cross section is such that the gas concentration on the side opposite to the suction side 34 of the casing 33 is high. In other words, B for A in the same figure
The side becomes gas rich.

Therefore, in this embodiment, as shown in FIG. The detection section 20 is located near one long side.

Therefore, in the case of this combustion device, when a flashback phenomenon occurs, the long sides a,
The flashback phenomenon on the long side b side of b will precede the flashback phenomenon, and the detection unit 20 will be located in the region where the flashback phenomenon precedes, and the above-mentioned effect will be exhibited.

In this embodiment, another detection section 25 is arranged on the other long side a, and this detection section 25 and the detection section 2
The misfire safety device 2 is activated by either output of 0.
is set to work. That is, when any of the above-mentioned detection sections no longer detects flame, the output valve 21 of the misfire safety device 2 closes to stop the gas supply.

This detection section 25 is a detection section for detecting that the flame formed in the flame hole section 10 is in a lifting state or a floating state. Since these lifting and floating occur on the air rich side, in the case of the above combustion equipment,
These incomplete combustions tend to occur on the long side a side of the flame hole portion 10. Therefore, in the case of combustion conditions that cause lifting or floating, the preceding incomplete combustion in the flame hole portion 10 can be reliably detected.

Normally, these lifting and floating phenomena and flashback phenomena do not occur at the same time, so in the case of this embodiment, the misfire safety device 2 will surely operate even if any incomplete combustion state occurs. Then, the gas supply pipe G is cut off and combustion is stopped.

[Brief explanation of the drawing]

Fig. 1 is an overall view of the embodiment of the present invention, Fig. 2 is a detailed view of the discharge port 31 and fan 3, and Fig. 3 is a detailed view of the flame hole portion 1.
0 is a perspective view of the conventional example, and FIG. 4 is a schematic diagram of a conventional example.
...detection section, 3...fan.

Claims (1)

[Scope of utility model registration request] A forced air supply fan feeds gas and combustion air into a relatively wide approximately rectangular flame hole 10 formed at the bottom of the combustion chamber 1, and a misfire safety device is installed in a part of this flame hole 10. A flashback safety device for a forced air combustion type combustion device in which a detection unit 20 is disposed on a side that becomes gas rich depending on the characteristics of an air supply fan 3. .