JPS6324352Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a safety device for combustion appliances such as gas water heaters.

In combustion appliances such as gas water heaters, if the exhaust passage is blocked due to clogging caused by condensate or combustion products such as soot adhering to the fins of the heat exchanger, resulting in insufficient exhaust, the combustion Since the amount of air supply required for the reaction cannot be secured, incomplete combustion occurs and the CO value in the combustion exhaust increases, which can lead to dangerous situations such as gas poisoning, which can have negative effects on the human body depending on the degree of blockage of the exhaust passage. becomes.

Therefore, by directing a part of the combustion exhaust in the combustion chamber through a conduit to near the flame port of the pilot burner that heats the thermocouple, which is the flame detection element, we can correct abnormalities caused by poor exhaust gas caused by clogged fins in the heat exchanger. Lifting of pilot burner flame for heating thermocouples,
A safety device for combustion appliances that immediately stops the fuel supply and ensures safety by rapidly reducing the thermoelectromotive force generated by the thermocouple and closing the electromagnetic safety valve, which is the main valve of the fuel, which causes deformation, fire extinguishment, etc. Already proposed (for example, Utility Model Application Publication No. 56-72054)
However, in this safety device, as shown in Fig. 3, when the main burner 9 is ignited, the pressure in the combustion chamber A _is
As the temperature increases, a part of the combustion exhaust gas is discharged through the conduit 01 from the lower end opening 06 facing near the flame port of the pilot burner 5 for heating the thermocouple, so that the pilot burner flame a for heating the thermocouple is blown out by the exhaust flow. Alternatively, significant deformation may occur, and while the conduit is cooling down after ignition, the heating of the thermocouple 10 by the pilot burner flame a for thermocouple heating is normal for a certain period of time (approximately 2 minutes) as shown by the broken line in Figure 4. will no longer be held. Therefore, main burner 9
In the initial stage of ignition, the thermoelectromotive force generated by the thermocouple 10 may suddenly drop, and the fuel supply may be unexpectedly stopped.

This invention was made with the aim of eliminating such drawbacks, and the upper end opening 3 of the conduit 1 disposed vertically along the inner shell 2 constituting the combustion chamber A is communicated with the upper part of the combustion chamber A. At the same time, the lower end opening 4 is bent in a direction substantially perpendicular to the conduit 1 so as to face near the flame opening of the pilot burner 5 for heating a thermocouple serving as a flame detection element, so that a part of the combustion exhaust in the combustion chamber A is channeled into the conduit. Pilot burner 5 for thermocouple heating through 1
An exhaust pressure relief port 7 is provided near the flame opening of the conduit 1 and opened substantially downward at the bent portion of the lower end of the conduit 1. This improves the stability of a safety device using a pilot burner by allowing the flame to be released quickly and preventing it from being blown onto the pilot burner flame for heating the thermocouple and affecting the pilot burner flame for heating the thermocouple. It is.

One embodiment will be described below based on the drawings.

In FIG. 1, reference numeral 1 denotes a conduit disposed on the outside of an inner shell 2 constituting a combustion chamber A in a substantially vertical direction along the inner shell 2, with openings 3 and 4 at both ends of the conduit 1 extending in a substantially perpendicular direction. The upper end opening 3 is connected to the upper part of the combustion chamber A near the heat exchanger B (described later), and the lower end opening 4 is provided horizontally at the upper part near the flame port of the pilot burner 5 for heating the thermocouple. are doing. In addition, the branch pipe 6 is connected downwardly at the bent portion of the lower end of the conduit 1 while maintaining substantially the same axis as the vertical part of the conduit 1,
An exhaust pressure relief port 7 is provided at the lower end of the conduit 1 and is oriented in a direction different from the lower end opening 4. In addition, in the case shown in FIG. 2, a downward opening approximately concentric with the conduit 1 is bored at the lower bent portion of the conduit 1, and the lower end opening is opened at the lower end of the conduit 1. 4 is provided with an exhaust pressure relief port 7 facing in a direction different from that of the exhaust pressure relief port 7.
is opened in a straight line direction (vertical direction). Therefore, a constant pressure is generated in the combustion chamber A after the main burner is ignited, and this pressure causes most of the combustion exhaust flow flowing down in the conduit 1 to be quickly released from these exhaust pressure relief ports 7. The exhaust flow immediately after the main burner is ignited is the pilot burner 5 for heating the thermocouple.
This is done so that it will not be blown onto the flame a and affect it. B is a heat absorption tube with fins 8
9 is a main burner, which is installed at the lower end of the inner shell 2.

Furthermore, when the appliance is cold, the conduit 1 is also cold, so the pressure P ₁ in the combustion chamber A, which has increased by igniting the main burner 9, tends to escape downward through the upper end opening 3. At this time, a part of the combustion exhaust enters into the conduit 1 from the upper end opening 3.However, since the conduit 1 is cold, the incoming combustion exhaust is cooled by this conduit 1 (according to actual measurements, the temperature at the upper end opening 3 is 250℃) The draft force _P2 in the conduit 1 is gradually attenuated.
Therefore, the combustion exhaust flows out at the exhaust pressure relief port 7 and the lower end opening 4 according to the pressure difference of P ₁ - _{P 2} , but as mentioned above, when the conduit 1 is cold, P ₁ - P The value of ₂ is large and a large amount of combustion exhaust flows out. However, as shown in the figure, the lower end opening 4 is opened at a position crossing (perpendicular to) the conduit 1, and the exhaust pressure relief port 7
Since the opening is in a straight line (perpendicular) position with respect to the conduit 1, when the pressure level P ₁ -P ₂ is large, it is mainly discharged through the exhaust pressure relief port 7.

After the main burner 9 is ignited, the combustion exhaust passes through the conduit 1 and the conduit 1 is gradually heated, so the amount of heat transferred to the conduit 1 decreases, and the combustion exhaust that enters from the upper end opening 3 is hardly cooled. It flows out from the exhaust pressure relief port 7 and the lower end opening 4. However, since the combustion exhaust temperature is high, the draft force _P2 increases compared to the initial stage of ignition. Therefore, the pressure difference between P ₁ and P ₂ becomes very small, and the amount of combustion exhaust gas flowing out from the lower end opening 4 becomes a small value from the initial stage of ignition, as shown by the solid line in FIG. 4. Here, if the exhaust passage is blocked due to clogging of the fins of heat exchanger B, etc., the CO concentration and pressure of the combustion exhaust in the combustion chamber A will gradually increase. Increase the flow rate from the relief port 7, and install the pilot burner 5 for heating the thermocouple.
Since a large amount is also released near the flame opening of the thermocouple, the oxygen concentration in the atmosphere decreases, promoting lifting, deformation, or extinguishment of the pilot burner flame a for heating the thermocouple, and greatly reducing the thermoelectromotive force generated by the thermocouple 10. This is to ensure safety by immediately closing the electromagnetic safety valve.

As explained above, this device quickly releases part of the combustion exhaust that flows out in large quantities through the conduit 1 at the time of ignition of the main burner or in the early stages of ignition from the exhaust pressure relief port 7, thereby generating the pilot burner flame a for heating the thermocouple. Since the adverse effects such as being blown out due to a large amount of exhaust flow are eliminated, the stability of the safety device using the pilot burner is improved and malfunctions are eliminated.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of this invention, Fig. 2 is a sectional view of a different embodiment, Fig. 3 is a partial sectional view of a conventional example, and Fig. 4 shows the amount of combustion exhaust flowing out to the pilot burner. This is a graph showing. 1... Conduit, 5... Pilot burner for heating the flame detection element, 7... Exhaust pressure relief port, A... Combustion chamber, a
...Pilot burner flame for heating the flame detection element.

Claims (1)

[Scope of utility model registration request] The upper end opening 3 of the conduit 1 disposed vertically along the inner shell 2 constituting the combustion chamber A is communicated with the upper part of the combustion chamber A, and the lower end opening 4 is connected to the conduit 1.
The opening is bent in a direction substantially perpendicular to the flame detection element and faces near the flame opening of the pilot burner 5 for heating the flame detection element, and
A discharge pressure relief port 7 opens substantially downward in the bent portion.
A safety device for combustion appliances with a branch.