JPS6330030Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an abnormal combustion detection device for burners of various gas combustion appliances such as gas water heaters and gas bath kettles.

A thermocouple for reverse bias and a thermocouple for safety valve are combined to cancel out the thermoelectromotive force as a means to detect abnormal combustion in the gas burner due to over-impact, fin clogging, oxygen deficiency, etc. and immediately stop the supply of gas. Although some methods have already been proposed to detect this phenomenon, this idea uses a reverse bias thermocouple installed with a certain gap in the vicinity of a fire guide plate that covers a part of the main burner flame. The aim is to improve safety by making the system sharp and reliable.

Hereinafter, one embodiment will be described in detail based on the drawings. In the drawings, reference numeral 1 denotes a flame port of a main gas burner A, and a part of the flame port 1 is covered with a flame guide plate 2 in the shape of a square. The burner flame from 1 is guided to the side. The fire guide plate 2 may be integrally formed by extending a part of the flame port wall of the main gas burner A as in the embodiment, or may be formed separately. Reference numeral 3 denotes an inverted inverter installed on one side of the fire guide plate 2, that is, on the side of the burner flames a and b guided by the fire guide plate 2, with a constant gap c in the horizontal direction from the side wall of the main gas burner A. This is a bias thermocouple, and is connected in opposite polarity to a safety valve thermocouple (not shown) built into a gas combustion appliance. Note that when the main gas burner A is burning normally, the reverse bias thermocouple 3 deforms and refracts the burner flame a guided by the fire guide plate 2 upward under the influence of the secondary air flow. Burner flame b that is not directly heated and expands and changes only during abnormal combustion
It is installed in a position where it can be heated.
Further, as shown in FIG. 3, the fire guide plate 2 may have a width such that its tip protrudes longer than the burner port 1, or extends over the two burner ports 1, 1.

Next, the operation of the above configuration will be explained.

(1) In the case of over-input detection, burner fire during normal combustion is caused by main gas burner A.
The burner flame a is lifted upward by the secondary air flow flowing in the direction of the arrow d through the gap c between the thermocouple 3 and the burner flame a, and although only a small thermoelectromotive force is generated in the thermocouple 3 due to exhaust heat and radiant heat, the overflow At the time of input, the burner flame extends diagonally upward and becomes burner flame b, so that the reverse bias thermocouple 3 is directly heated by burner flame b and generates a large thermoelectromotive force. Therefore, the thermoelectromotive force of the safety valve thermocouple connected to the opposite polarity is canceled out, and the safety valve immediately closes to stop the gas supply.

According to experiments, the thermoelectromotive force generated in the reverse bias thermocouple 3 in this case is approximately 7.5 mV due to exhaust heat and radiant heat during normal combustion, but when abnormal combustion occurs due to over-impact, the thermoelectromotive force generated in the burner Direct heating by flame b, exhaust gas CO/CO ₂ = 0.01
At the time of , it was 22.0mV.

(2) In the case of fin clogging detection, the burner flame during normal combustion is the main gas burner A.
The burner flame a is lifted upward by the secondary air flow flowing in the direction of the arrow d through the distance c between the thermocouple 3 and the burner flame a, and only a small thermoelectromotive force is generated in the thermocouple 3 due to exhaust heat and radiant heat. When the fins become clogged, the secondary air flow in the direction of arrow d is extremely reduced, and the burner flame is displaced and elongated in the direction of thermocouple 3, becoming burner flame b, which directly heats thermocouple 3, thereby reducing its heat. The electromotive force increases, and as in the case of over-input, the gas supply is immediately stopped to ensure safety. According to experiments, the thermal electromotive force in this case is 7.5 mV during normal combustion, and when abnormal combustion due to fin clogging occurs, the exhaust gas CO/CO ₂ = 0.01.
At the time of , it was 15.0mV. Note that the same applies to oxygen-deficient conditions.

As explained above, this idea has a simple structure in which reverse-bias thermocouples are installed at regular intervals near a 〓-shaped fire guide plate that covers a part of the main burner flame opening. Abnormal combustion such as over-impact, fin clogging, or oxygen deficiency is detected sensitively and reliably using a part of the main gas burner flame, and the thermoelectromotive force generated by the thermocouple for the safety valve is canceled out and the supply gas is immediately stopped. It is highly safe for actual use.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of this invention, FIG. 2 is a sectional view, and FIG. 3 is a plan view showing another embodiment. A...Main gas burner, 1...flame mouth, 2...
Fire guide plate, 3...Reverse bias thermocouple.

Claims (1)

[Scope of utility model registration request] In a device that combines a thermocouple for excitation of a safety valve and a thermocouple for reverse bias to offset and eliminate thermoelectromotive force during abnormal combustion, a thermocouple for reverse bias 3 is provided to cover a part of the flame port 1 of the main gas burner A. Detection of abnormal combustion in a burner characterized in that a horizontal gap c is installed near the tip of a flame guide plate 2 which is hardly heated during normal combustion but heated during abnormal combustion. Device.