JPH0545443U - Incomplete combustion detector for gas burner - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To obtain a device that can reliably detect incomplete combustion due to lack of oxygen in the gas burner. [Arrangement] A bar plate 6 for deflecting the flame laterally is provided on the flame port of the burner body 1, and a slit 8 is provided in the bar plate 6 so as to cross the flame port. 9
Is installed to detect the temperature of the flame. When the oxygen content in the air decreases, the flame expands and the temperature becomes low, so the output of the thermocouple 9 gradually decreases, but in the practical range where the oxygen concentration is around 19%, the flame lift phenomenon is suppressed by the side plate 6. The heating of the thermocouple 9 is continued. When it becomes about 17% of hypoxia,
The gas emitted from the slit 8 becomes unburned, and the flame emitted from the tip of the covering plate 6 is pushed up into a lift shape, the output of the thermocouple 9 is sharply reduced, and the operation of the safety device is facilitated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for detecting incomplete combustion of a burner such as a water heater and a bath kettle.

[0002]

[Prior Art]

 If the place where the gas burner is installed becomes oxygen-deficient due to poor ventilation, etc., the amount of CO generated will increase and it is necessary to stop combustion. However, even if the oxygen concentration decreases, it does not hinder practically if the concentration is about 19%, but since CO rapidly increases at about 17%, it is desirable to set this about 17% as a standard for stopping.

When the gas burner is in an oxygen-deficient state, the flame exiting the flame opening gradually expands in accordance with the decrease in oxygen concentration, and a lift phenomenon occurs in which the flame leaves the flame opening, and the temperature at a fixed point on the flame opening gradually decreases. Therefore, a means for placing a thermocouple at this point to detect oxygen deficiency and stop combustion is conventionally known. However, by this means, the oxygen deficiency state can be detected, but it is difficult to distinguish between 19% and 17% when a gas that easily lifts is used. That is, even if it is about 19%, the lift phenomenon occurs and the safety device operates.

Therefore, there is also known a device in which a flame lift phenomenon is suppressed by providing a slat plate at the upper part of the flame opening so that combustion can be continued at about 19% even with a gas that is easy to lift (Jitsuko Sho 60-16857). issue). However, even with this device, it is difficult to distinguish between the concentrations of 19% and 17%. The reason is that even when the combustion stop is desired at about 17%, the side plate suppresses the lift phenomenon.

[0005]

[Problems to be solved by the device]

 An object of the present invention is to obtain means for easily detecting a hypoxic state where the oxygen concentration is about 17%.

[0006]

[Means for Solving the Problems]

 Means for solving the above-mentioned problems in the present invention is to provide an upper side of a flame opening with a bar plate for preventing the rise of the flame, and a thermocouple facing the tip side of the side plate to detect the temperature of the flame. In the incomplete combustion detection device of the gas burner, which is designed to operate the safety device with the output of the thermocouple, the slit is formed on the side plate across the upper part of the flame opening and opens on the side of the thermocouple. The thermocouple is positioned above the tip and close to the opening of the slit.

[0007]

[Action]

 Even if the gas is easy to lift, the flame is suppressed by the side plate, and when the oxygen concentration is about 19%, the thermocouple is heated and a sufficient electromotive force is generated. However, when the oxygen concentration further decreased to about 17%, the ejection speed of the gas passing through the slit exceeded the combustion speed, and the gas passing through the slit was released in an unburned state, which rose from the tip of the plate and burned. It lifts the existing flame and causes a lift phenomenon. Due to this lift, the electromotive force of the thermocouple sharply decreases, and the safety device can be operated reliably.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 is a burner unit, which is formed by combining two corrugated plates with a trapezoidal concavo-convex pattern formed continuously and one flat plate, and has a large width W of about 3 mm at the upper end. The flame openings 2 are formed in two rows. Reference numeral 3 is a board such as a board, which is fixed by engaging the bent portions 4 and 4 and the claw pieces 5 on both sides with the concave surface of the burner unit 1, and the board 6 of the present invention is extended to the board 3. The ignition electrode 7 is provided so as to project upward. The electrode 7 generates an ignition fireworks with an igniter (not shown). The backing plate 6 suppresses the flame emitted from the flame port 2 at the upper side, and has a slit 8 which crosses the upper portion of the flame port 2 and reaches the tip 6a in the center, and the thermocouple is opposed to the opening of the slit 8. 9 is provided. In addition, 10 is a flame rod, which is used to instantaneously detect ignition by utilizing the conductivity of the flame. It is provided between the two flame ports 2 and 2 arranged side by side, and the flame at the beginning of ignition tends to lift. It is designed to detect flames even at times.

In FIG. 2, A to G show various kinds of side plates used for the test, of which A, B and C have a depth of 5 mm, a plate thickness of 1 mm and a tip 6 a from the side end 1 a of the burner unit 1. It projects approximately 1 mm, and D, E, F, and G have a depth of 7 mm, a plate thickness of 1 mm, and a tip projecting approximately 3 mm from the burner unit 1 and placed 2 mm above the flame outlet 2. .

The above-mentioned boards A, B, and C have the same size, but A does not have a slit, and B and C have slits. 3 (a) to 3 (c) show details of the barrier plates B and C, the length of the slit 8 is 4 mm, and the width S of the slit 8 is 0.7 mm for B and 1.5 mm for C. is there . FIG. 4 shows data obtained when the lift system gas (13A-1) was burned by using the board A, B and C. In FIG. 4, the vertical axis represents the electromotive force of the thermocouple 9 and CO / CO ₂ , the horizontal axis represents the oxygen concentration of the air supplied to the burner unit 1, and the curves (A), (B), and (C) are the plate shapes, respectively. The data when using A, B, and C are shown, and the curve (P) shows the ratio of CO and CO _{2 in} the exhaust gas, which was a substantially constant ratio for each plate.

In FIG. 4, in each of the curves (A), (B), and (C), the electromotive force sharply decreases at the boundary of O ₂ ≈17.5%, but the decrease rate of the curve without slit (A) is low. The curves (B) and (C) with slits have a large reduction rate, and the output is about 5 mV or less, which is less than half the value when O ₂ = 19%, which allows use of the burner. As a result, a sufficient thermocouple output can be obtained up to an oxygen concentration of about 18% even with a lift type gas. It can be seen that the output drops significantly at around 5%.

Next, FIGS. 5 (a) to 5 (d) show the details of the side plate 6 shown in D, E, F, and G of FIG. 2, and show the data when the side plate 6 is used. 6 shows curves (D) to (G). Curve (D) in FIG. 5 (a) without slits, curve (E) in FIG. 5 (b) with slits having a length of 1.5 mm and a width of 2.0 mm are shown in FIG. 5 (c). Of the slit 8 of 2.0 mm in length and width is a curve (F), and the slit of FIG. 5 (c) is a curve of FIG. 5 (d) in which a slit having a length of 4 mm and a width of 1 mm is connected. Expressed as (G), the electromotive force sharply decreases in the vicinity of the oxygen concentration of 16.7%, and only the curve (G) decreases to about 5 mV or less.

From the above test results, the structures shown in B, C and G in FIG. 2 having the performances indicated by the curves (B), (C) and (G), that is, the flame plate 2 is crossed across the flame plate 2. It can be seen that the one having the slit 8 has a larger decrease in electromotive force than the others.

As described above, in the case where the flame plate is not provided on the flame mouth, when the lift type gas is used, even if the concentration is 19%, the gas tends to lift and the output of the thermocouple lowers, and the electromagnetic safety valve closes. Further, when the slits A and D without slits or the slits E and F with slits that do not cross the slit 2 even if there are slits are provided, the flame is indicated by f ₁ in FIG. 3B. As described above, the lift phenomenon at 19% is suppressed and combustion continues, but it is desired to stop combustion. Even at about 17.5%, the lift is suppressed by the plate, and the flame is f ₂ in Fig. 3 (b). As shown in the figure, the flame is held at the tip of the sheet to heat the thermocouple, and no large output decrease is seen as shown in the curves (A) and (D) (E) (F) of FIG.

However, in the case plates B, C, and G in which the slit 8 crosses the flame port, the flame is shown in FIG. ₃ As shown in FIG. 4, the flame lifts at the slit portion, and the heating force for the thermocouple is reduced, and the output greatly decreases as shown by the curves (B) and (C) in FIG. 4 and the curve (G) in FIG. The reason for this is that the velocity of the gas ejected through the slit exceeds the combustion velocity and is released unburned. It is thought to be due to peeling and lifting, and separating the center of the flame root from the thermocouple.

The stave plate 6 is not limited to the one shown in FIGS. 2B, 2C, 2G and 2C, but may have the structure shown in FIGS. 7 (a) has a slit 8 having a semicircular top and a divergent opening, and in FIG. 7 (b) has an inverted U-shaped slit 8. 8 is provided with a portion 11a having the slit 8 and a portion 11b having no slit. In the case of a liftable gas, this plate 11 is attached so that the thermocouple 9 faces the slit 8 and, in the case of a gas that is not liftable, the thermocouple faces the slitless portion 11b.

Although the slit 8 is opened only on the thermocouple side in the above embodiment, it may be extended to the dual side.

The decrease in electromotive force thus obtained is directly used, or another thermocouple of about 5 mV by another thermocouple which detects the clogging of the heat exchanger incorporating the burner body 1 by changing the temperature is used. The back electromotive force may cancel the reduced electromotive force to close the electromagnetic safety valve. Further, in this embodiment, it is explained that it is provided on the flame mouth of the main burner, but it may be provided on the burner for detecting incomplete combustion.

[0019]

[Effect of the device]

 As described above, according to the present invention, the slit facing the thermocouple side is provided across the upper part of the flame mouth, and the thermocouple is positioned above the tip of the plate and close to the opening of the slit. Even if the temperature is lowered to a low level, the lift can be suppressed by the plate to continue combustion, and when the oxygen concentration further decreases to about 17%, unburned gas passing through the slit causes the flame at the edge of the slit at the slit. Since the amount of heat applied to the thermocouple is lowered by pushing it up into a lift shape, the output of the thermocouple is reduced and combustion can be reliably stopped.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a test example.

FIG. 3 is an explanatory diagram of a part of the configuration of the test example.

FIG. 4 is a diagram showing test results of the same example.

FIG. 5 is an explanatory diagram of the configuration of another test example.

FIG. 6 is a diagram showing test results of the same example.

FIG. 7 is a plan view of another embodiment.

FIG. 8 is a plan view of still another embodiment.

[Explanation of symbols]

2 Flame mouth 6 Plate 8 Slit 9 Thermocouple

Claims (1)

[Scope of utility model registration request] 1. An upper part of the flame opening is provided with a side plate for preventing the rise of the flame, and a thermocouple is provided facing the tip side of the side plate to detect the temperature of the flame, and the output of the thermocouple during low oxygen. In an incomplete combustion detection device for a gas burner, which is designed to operate the safety device with a slit, a slit opened across the upper part of the flame mouth on the thermocouple side is provided on the side plate, and the slit above the tip of the side plate. An incomplete combustion detection device for a gas burner, characterized in that a thermocouple is positioned close to the opening.