JPH0356752Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention mainly relates to a thermocouple device used for controlling the air-fuel ratio of a premix burner.

(Prior art) As a conventional device of this kind, a through hole is provided in the combustion plate of a burner having a plurality of flame holes, a heat sensitive part of a thermocouple is inserted into the through hole, and the temperature of the combustion gas is determined by the thermocouple. It is known that the detection output is used to control the opening and closing of an on-off valve installed in the supply path to the burner.In this case, in order to obtain an accurate detection output from the thermocouple, Generally, the tip of the heat-sensitive portion is made to protrude from the upper surface of the combustion plate by a desired length, for example, about 2 mm.

(Problems to be solved by the invention) However, as shown in FIG. A locking piece e is provided to allow the tip of the heat sensitive part b to protrude from the upper surface of the combustion plate d, and the combustion plate d is generally made of a ceramic plate with a thickness of 10 mm or more. It has been difficult to make the tip of the heat-sensitive part b protrude from the upper surface of the combustion plate d by a desired length, for example, about 2 mm, because the heat-sensing part b may have different values or its accuracy may be poor.

(Means for solving the problem) The present invention is designed to always keep the tip of the heat-sensitive part at a desired distance from the top surface of the combustion plate, for example, 2 minutes, even if the thickness of the combustion plate is different.
The purpose of the present invention is to provide a device in which the combustion plate of a burner having a plurality of flame holes is provided with a through hole, a heat sensitive part of a thermocouple is inserted through the through hole, and the thermocouple is The temperature of the combustion gas is detected by the sensor, and the combustion of the burner is controlled based on the detected output. It is characterized by being provided with a locking piece.

(Function) The present invention has the above-mentioned configuration. According to this, the locking piece provided on the heat-sensitive part of the thermocouple is located on the upper surface of the combustion plate, so the tip of the heat-sensitive part is attached to the combustion plate. Regardless of the thickness, it can always be made to protrude from the upper surface of the combustion plate by a desired length, for example, about 2 mm.

(Example) Next, an example in which the present invention is applied to air-fuel ratio control of a gas water heater will be described based on the drawings.

In Fig. 1, 1 is a gas water heater main body that has an intake port 2 at the bottom and an exhaust pipe 3 at the top. The burner 5 is housed in a combustion case 8 that includes a fan 6 for supplying combustion air to the burner 5 in the lower part of the interior, and an exhaust port 7 connected to the exhaust pipe 3 in the upper part of the interior, and is located on the upstream side of the heat exchanger 4. The water sent from the water supply pipe 9 is heated in the heat exchanger 4 so that hot water can be obtained from the hot water outlet pipe 10 on the downstream side of the heat exchanger 4, and the combustion exhaust is passed through the exhaust pipe 3. I decided to release it to the outside.

In the figure, reference numeral 11 indicates a gas supply path whose tip nozzle portion 11a faces into the mixing section of the burner 5 in order to supply gas to the burner 5.
1 was provided with an electromagnetic proportional control valve 12.

The temperature of the hot water is controlled by a general combustion control device 13 equipped with an operational amplifier.
The opening degree of the electromagnetic proportional control valve 12 and the rotation speed of the fan 6 are changed according to the magnitude of the difference signal between the hot water temperature signal and the set temperature signal from the temperature sensing element 14 provided in the burner 5. This is done by increasing or decreasing the gas supply amount and air supply amount.

In the premix burner 5, the air-fuel ratio may deviate from the appropriate range for good combustion due to fluctuations in intake and exhaust pressures, fluctuations in gas components, etc., so air-fuel ratio control is required to correct this. .

This air-fuel ratio control is generally performed by utilizing the fact that the temperature of combustion gas and the air-fuel ratio are inversely proportional. Specifically, a through hole 15 is provided in the combustion plate 5a of the burner 5, and a thermoelectric Heat sensitive part 16 of pair 16
a, the temperature of the combustion gas is detected by the thermocouple 16, and the mixture consisting of combustion air and gas is inputted to the combustion control device 13 which controls the detection output and is supplied to the burner 5. The electromagnetic proportional control valve 12 ensures that the air-fuel ratio is always within the appropriate range.
This is done by correcting at least one of the opening degree of the fan 6 and the rotation speed of the fan 6.

Here, in the present invention, the heat sensitive part 16a of the thermocouple 16
A locking piece 17 is provided on the peripheral edge of the through hole 15 to be locked on the upper surface side of the combustion plate 5a. Specifically, as shown in FIG. A locking piece 17 made of a ceramic needle, rod, or plate is provided at the tip, and the locking piece 17 connects the thermocouple 1 from below the combustion plate 5a.
The combustion plate 5a is held between a so-called speed nut 18 shown in FIG. Electrodes 161, 162
A thermocouple 16 having a heat-sensitive portion 16a consisting of
The upper part of the flange of the combustion plate 5a is welded to the upper end of the internal electrode 161, and the thermocouple 16 thus constructed is attached to the heat-sensitive part 16a through the transparent parts of the combustion plate 5a, which is made by combining the divided pieces as shown in FIG. The thermocouple 1 is inserted into the hole 15, and the combustion plate 5a is held between the locking piece 17 and the speed nut 18 as shown in FIG.
6 is fixed. In this case, the heat-sensitive part 16a of the thermocouple 16 can always protrude by a desired length, for example, 2 mm, from the upper surface of the combustion plate 5a, and an accurate detection output can be obtained from the thermocouple 16. By controlling the air-fuel ratio using the detected output, the air-fuel ratio can always be maintained within an appropriate range for obtaining good combustion.

Note that if the locking piece 17 is made of a plate-like body with good thermal conductivity, the heat receiving area of the heat sensitive part 16a becomes large, so subtle differences in thermoelectromotive force due to variations in the processing of the thermocouple 16 may occur. It is even more advantageous to be able to compensate for

Incidentally, reference numeral 19 in FIG. 1 indicates an electromagnetic on-off valve that opens and closes in response to commands from the combustion control device 13 to allow gas to pass through.

The above-mentioned embodiment is a case in which the present invention is applied to the air-fuel ratio control of a gas water heater, but the present invention is not limited to this. For example, as shown in Figs. Of course, it is also possible to apply the present invention to the rotational speed control of the fan 21 in the indoor open type warm air heater 20, the opening degree control of the proportional valve 22, and the air-fuel ratio control.

(Effects of the invention) As described above, according to the present invention, a locking piece is provided on the heat-sensitive portion of the thermocouple to be locked on the periphery of the through hole on the upper surface side of the combustion plate. The heat sensitive part is provided with a locking piece that can be made to always protrude a desired length from the top surface of the combustion plate regardless of the thickness of the combustion plate, and that is locked on the peripheral edge of the through hole on the bottom side of the combustion plate. Compared to the above-mentioned conventional method, the present invention has the effect of performing highly accurate control such as air-fuel ratio control.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the first embodiment of the present invention, Fig. 2 is a cutaway front view showing the main parts, and Fig. 3 is the second embodiment.
FIG. 4 is a cutaway front view showing a thermocouple according to the second embodiment of the present invention; FIG. 5 is a cutaway front view showing the main parts of the second embodiment of the present invention. , FIG. 6 is an explanatory diagram showing a third embodiment of the present invention, FIG. 7 is a cutaway side view of the embodiment of FIG. 6, and FIG. 8 is a cutaway front view showing the main parts of the conventional example. 5...Burner, 5a...Combustion plate, 15...Through hole, 16...Thermocouple, 16a...Heat sensitive part, 17...
...Latching piece.

Claims (1)

[Scope of utility model registration request] A through hole is provided in the combustion plate of a burner having multiple flame holes, a heat sensitive part of a thermocouple is inserted into the through hole, the temperature of the combustion gas is detected by the thermocouple, and the combustion of the burner is controlled by the detected output. 1. A thermocouple device, characterized in that the heat sensitive section is provided with a locking piece that locks on the periphery of the through hole on the upper surface side of the combustion plate.