JP2567189Y2 - Double mixing tube type gas burner - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double mixing pipe type gas burner in which a small mixing pipe is opened in a main mixing pipe.

[0002]

2. Description of the Related Art A gas burner used for a gas stove has a structure in which gas ejected from a nozzle and primary air are mixed in a mixing pipe and supplied to a burner head.
In the mixing tube, the primary air moves toward the burner head with a certain kinetic energy. For this reason, when adjusting the thermal power by reducing the amount of gas sent to the nozzle, if the gas amount is suddenly reduced or if the gas is stopped under a relatively high heat, the primary air will lose its inertia. As a result, excess air is sucked into the mixing pipe in an attempt to continue moving, and the balance of the mixing ratio is lost, making it difficult to shift to a small flame smoothly or causing abnormal combustion.

In order to solve this problem, the present applicant has provided a small-fire mixing tube that can be adjusted separately from the main mixing tube, and introduces the small-fire mixing tube into the main mixing tube so that the small-fire mixing tube can be installed in the downstream direction. (Japanese Patent Application Laid-Open No. 64-23009) has already been proposed. According to this proposal, even when the gas supplied to the main mixing pipe is suddenly stopped or the heating power is reduced, a certain amount of gas is supplied from the small fire mixing pipe, so that the primary The amount of air is relatively small, and extra combustion is unlikely to occur due to the extra air being sucked into the mixing pipe. It is easy to obtain a gas burner.

[0004]

[Problem to be Solved by the Invention] In the burner proposed above, air is gradually sucked into the main mixing pipe by the mixed airflow spouting from the mixing pipe for the small fire when using the small fire. Since the upstream of the pipe tends to be in an air-rich state, when gas is supplied to the main mixing pipe after switching from small fire to large fire, the air-rich part of the air-fuel mixture is sent to the burner head. May cause fire.

As measures to prevent this, (a) the damper opening of the main mixing pipe is reduced. (b) Increase the flame load.
(c) Provide a flow straightening plate in the mixing tube. (d) Increase the amount of input during small fires. (e) Interlocked dampers. Etc.,
By implementing these alone or in combination, it is possible to prevent flashback. But above
In (a), CO / CO ₂ deteriorates. In (b) and (c), the suction decreases. In (d), the thermal power adjustment function decreases. In (e), the structure becomes complicated. And other problems tend to occur. This invention has been made in view of the above-mentioned problems, and has as an object to obtain an excellent prevention measure against flashback when switching the thermal power in a double-mixed pipe gas burner.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a double mixing pipe type having a structure in which a small-fire mixing pipe is introduced into a main mixing pipe and is opened downstream. In the gas burner, a sub-opening that opens into the main mixing pipe upstream of the opening in the small-fire mixing pipe is provided.

[0007]

[Function] Since the air-fuel mixture in the small-fire mixing pipe is supplied to the main mixing pipe from the sub-opening, the gas concentration in the upstream portion of the main mixing pipe that is likely to be in an air-rich state increases, and at the same time, the air flows into the main mixing pipe. Is also suppressed, and flashback when switching from small fire to large fire is prevented.

[0008]

Next, one embodiment shown in the drawings will be described. In the figure, 1 is a burner head composed of a burner top 2 and a burner base 3, 4 is a main mixing pipe connected to the burner base 3, 5 is a main nozzle connected to the lower end of the main mixing pipe 4, and 6 is A small fire mixing pipe 7 is a small fire nozzle connected to the small fire mixing pipe 6. This small fire nozzle 7
Is capable of adjusting the gas amount separately from the main nozzle 5, and the nozzle 5 and the nozzle 7 and related members around these nozzles suck primary air at a predetermined ratio by a conventionally known appropriate structure. It is configured to generate an air-fuel mixture.

The burner head 1 is of an annular shape having a hole 11 vertically penetrating at the center, and a plurality of flame holes 12 are formed at a predetermined interval on the peripheral surface of the burner top 2. A chamber 13 is provided in one place, and an ignition plug 14 and a thermocouple 15 are arranged. In the figure, the flame outlet 12 is 1
Only one is shown. The main mixing pipe 4 is provided vertically at a position opposite to the sub-combustion chamber 13.
Is introduced into the main mixing tube 4 from below, and is located at the most eccentric position, that is, the position farthest from the center line of the burner head 1. An orifice 16a is provided at the tip of the small fire mixing pipe 6 to form a main opening 16 that opens downstream, that is, upwards. A sub-opening 17 that opens toward the center of the tube 4 is formed.

Reference numeral 21 denotes a heat-sensitive part, 21a denotes a lead wire of the heat-sensitive part 21, 22 denotes a support rod of the heat-sensitive part 21, and 23 denotes a heat-sensitive part cover. The support rod 22 is appropriately fixed to a mounting plate 24 provided in an instrument body (not shown) and inserted into the hole 11 of the burner head 1, and the heat-sensitive portion 21 can move to a tip of the support rod 22 in a certain range in the vertical direction. As described above and in a state of being urged upward by a spring. The upper part of the heat-sensitive portion cover 23 is tapered to form a large-diameter portion 23a.
A plurality of ventilation holes 23c are formed at regular intervals in the tapered portion 23a, and are integrally formed on the central upper surface of the burner top 2 by an appropriate means using, for example, a C-ring. Fixed.

This embodiment is configured as described above, and the operation will be described next. At the time of use, the thermosensitive portion 21 is pressed down by contacting with a pot (not shown), the temperature of the pot bottom is detected by a built-in thermocouple, a thermistor, or the like, and the result is used for control. Most of the radiant heat due to the flame or the like coming out of the flame outlet 12 is blocked by the heat-sensitive part cover 10 and does not reach the heat-sensitive part 21, and the heat-sensitive part 21 is cooled by the rising airflow passing through the hole 11. Accurately detected. The gas to the burner head 1 is mainly supplied from the main nozzle 5, and the air-fuel mixture produced by mixing with the primary air rises in the main mixing pipe 4 with a certain kinetic energy, and also from the small fire nozzle 7. A small amount of gas is supplied, and the air-fuel mixture is discharged from the main opening 16 and the sub-opening 17 of the small-fire mixing tube 6 into the main mixing tube 4 as shown by an arrow in FIG.

Here, a cock for the supply path to the main nozzle 5
(Not shown), the gas ejected from the main nozzle 5 is suddenly stopped or throttled, and the mixing pipe 4
The air-fuel mixture therein rises as it is due to its inertia, and the primary air continues to be sucked in from around the main nozzle 5. However, the suction of the primary air is suppressed to some extent by the air-fuel mixture from the small-fire mixing tube 6 discharged into the main mixing tube 4 from the main opening 16 and the sub-opening 17, and furthermore, the small-fire mixing tube 6 Since the amount of primary air in the main mixing pipe 4 becomes relatively small due to the above-mentioned gas, abnormal combustion or the like due to excess air in the air-fuel mixture is less likely to occur, and operations such as adjusting the heating power to a small fire become stable. Done.

On the other hand, even when the gas from the main nozzle 5 is stopped and the small mixture is used only by the air-fuel mixture from the small-mixture mixing tube 6, air is sucked into the main mixing tube 4 little by little. If there is no sub opening 17, air is likely to accumulate in the portion A indicated by a chain line near the entrance of the main mixing pipe 4. For this reason, when gas is supplied to the main mixing pipe 4 after switching from small fire to large fire, the air-rich mixture of the portion A is sent to the burner head 1 so that combustion is possible without secondary air. In this case, a flashback phenomenon in which the flame burns back into the burner head 1 occurs.

However, in this embodiment, the sub-opening 17 is opened toward the center of the main mixing pipe 4 and a part of the air-fuel mixture is blown out from the small-fire mixing pipe 6 as indicated by a broken arrow. Therefore, the gas concentration in the portion A where air accumulation is likely to occur increases,
In addition, the flow of the air-fuel mixture from the sub-opening 17 covers the lower end of the main mixing pipe 4 and acts as a curtain to suppress the intake of new air. This makes it possible to prevent an air-rich mixture that can be burned without secondary air from being generated in the portion A. For example, based on the results of experiments and the like, the main opening portion 16 and the sub opening portion can be prevented. 1
By setting the opening area of 7 to an appropriate value so that the condition for the occurrence of flashback is not satisfied, flashback when switching from small fire to large fire can be prevented.

[0015]

As is apparent from the above-described embodiment, the present invention relates to a double mixing pipe type gas burner in which a small fire mixing pipe is introduced into a main mixing pipe and is opened downstream.
An auxiliary opening that opens into the main mixing pipe upstream of the opening of the small fire mixing pipe is provided in the small fire mixing pipe. Therefore, the gas mixture supplied to the main mixing pipe from the sub-opening of the mixing pipe for small fire increases the gas concentration in a portion that is likely to be in an air-rich state upstream of the main mixing pipe when used with small fire. However, it is possible to prevent the occurrence of flashback at the time of switching from small fire to large fire with a simple structure without causing the problems such as the countermeasures (a) to (e) described above. It is easy to obtain a gas burner which is wide and has good operability.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 burner head 4 main mixing pipe 5 main nozzle 6 small fire mixing pipe 7 small fire nozzle 16 main opening 16a orifice 17 sub opening

Claims (1)

(57) [Scope of request for utility model registration] 1. A small fire mixing pipe which can be adjusted separately from the main mixing pipe, and the small fire mixing pipe is introduced into the main mixing pipe and provided with an opening which opens in the downstream direction. A double mixing pipe type gas burner comprising a small mixing pipe having a sub-opening which opens into the main mixing pipe upstream of the opening.