JPH063301B2 - Exhaust gas detector for gas combustion equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas detection device used for detecting a combustion state of a gas combustion device and the like.

(Prior Art) Air is blown from a blower fan into a case having a gas burner inside, and the combustion gas generated by burning the gas ejected from the gas burner by this air is exhausted to the outside through an exhaust passage that is hermetically connected to the case. 2. Description of the Related Art There are some gas-fired appliances that emit gas by providing a gas detection element in the exhaust passage to detect a combustion state such as incomplete combustion and thereby control the operation of the appliance.

(Problems to be Solved by the Invention) In such an exhaust gas detection device, since the gas detection element is provided in the exhaust passage, the gas detection element is easily exposed to high temperature and deteriorates, and thus has poor durability. There is. Also, since the gas components in the exhaust passage differ from place to place, it is not possible to detect the average combustion gas component, and the equipment installation conditions, including errors in the shape and dimensions of individual equipment and the shape of the exhaust duct, etc. If the flow in the exhaust passage changes due to this, the gas component at the location where the gas detection element is installed also changes subtly, so there is a problem that detection variation becomes large and detection accuracy decreases. The present invention is intended to solve each of these problems.

(Means for Solving Problems) For this reason, the exhaust gas detection device for a gas combustion apparatus according to the present invention has a gas burner 20 inside as illustrated in the accompanying drawings.
Air is blown from the blower fan 25 into the case 10 provided with the above, and the combustion gas generated by burning the gas ejected from the gas burner 20 by this air is discharged to the outside through the exhaust passage 16 airtightly connected to the case 10. In the gas combustion device, the detection box 30 having the gas detection element 40 inside is opened in the detection box 30 at different positions, and the detection box is provided on the exhaust passage 16 and the suction side of the blower fan 25, respectively. First and second communication paths 3 communicating with each other
5, 36, and a semi-fixed flow control valve 32 provided in an intake hole 31 for introducing outside air into the detection box 30.

(Operation) Due to the negative pressure generated on the suction side of the blower fan 25 during the operation of the gas combustion device, the gas in the detection box 30 is sucked through the second passage 36, and accordingly, is sucked through the first passage 35. The high temperature combustion gas in the exhaust passage 16 and the ambient temperature air sucked through the intake port 31 are mixed in the detection box 30 and become lower in temperature than the combustion gas in the exhaust passage 16,
The gas component to be detected therein is detected by the gas detection element 40. Then, in a state where the gas combustion equipment is installed at each use place, when the average concentration of the gas component to be detected in the exhaust passage 16 reaches a predetermined value, the detection box 3
The flow rate control valve 32 is adjusted and fixed so that the concentration of the gas component to be detected in 0 becomes a predetermined set value. As a result, the gas detection element 40 detects the gas component in the detection box 30, and thereby the average concentration of the gas component to be detected in the exhaust passage 16 is detected with high accuracy.

(Effects of the Invention) As described above, according to the present invention, the gas detection element is not directly exposed to the high-temperature combustion gas in the exhaust passage, but is mixed with the air sucked from the intake port in the detection box to obtain the temperature. Since it only comes into contact with the combustion gas whose temperature has decreased, the temperature does not become so high, and therefore the durability of the gas detection element can be improved. In addition, since the gas detection element can be adjusted after installation so as to detect the average concentration of the gas component in the exhaust passage, the installation conditions of the equipment such as variations in the shape and dimensions of individual equipment and the shape of the exhaust duct can be adjusted. It is possible to detect the components of the combustion gas without causing an error due to the change.

(Examples) The present invention will be described below with reference to Examples shown in the accompanying drawings.

As shown in the drawing, the case 10 of the instant gas water heater is the inner case 1
1 and the outer case 12, the combustion air supplied from the blower fan 25 attached to the bottom surface of the outer case 12 is
Through the passage formed between 1, 12 and the partition plate 13,
It flows into the inside 11 from the lower side. A fin-tube type heat exchanger 15 and an exhaust passage 16 including an exhaust hood 17 and an exhaust duct 18 are airtightly connected to the upper side of the inner case 11, and a gas burner 20 is provided in a lower part of the inner case 11. . The gas supplied through the gas passage 21 and ejected from the gas burner 20 is burned in the inner case 11 by the combustion air from the blower fan 25, and the high-temperature combustion gas generated thereby is in the water pipe 15 a of the heat exchanger 15. The water flowing through is heated and discharged through the exhaust passage 16 indoors or outdoors.
The gas passage 21 is provided with a solenoid valve 22 and a gas amount adjusting valve (not shown) described later.

A gas detection element 40 for detecting harmful components such as carbon monoxide is provided inside the detection box 30 which is an essential part of the present invention.
As shown in the drawing, the upper portion thereof is communicated with the inside of the exhaust hood 17 through the first communication passage 25, and the lower portion thereof is connected with the second communication passage 36.
It is communicated with the inside of the suction port 26 of the blower fan 25 via. Further, the detection box 30 is provided with an intake hole 31 communicating with the outside air, and the intake hole 31 has a semi-fixed flow rate control valve 3
Two are provided. The flow rate control valve 32 is held at the opening degree after manually adjusting the opening degree, and the detection box 3 is externally connected.
The butterfly valve is used in this embodiment to control the amount of air flowing into 0, but it may be a sluice valve or a needle valve. The control device 41 is the gas detection element 40.
If the concentration of carbon monoxide in the detection box 30 detected by means of a predetermined value is set, the solenoid valve 22 is closed and the gas burner 20 is closed.
It shuts off the gas supply to.

The blower fan 25 is operating during operation of the instantaneous gas water heater, and a predetermined negative pressure is generated at a position inside the suction port 26 where the tip of the second communication passage 36 is opened. This negative pressure causes the detection box 3
The gas in 0 is sucked into the blower fan 25 at a constant rate, while the high temperature combustion gas in the exhaust hood 17 and the outside air enter the detection box 30 via the first communication passage 35 and the intake hole 31, respectively. After being sucked and mixed, the temperature thereof becomes lower than the combustion gas temperature in the exhaust hood 17, and the carbon monoxide concentration therein is detected by the gas detection element 40. The carbon monoxide concentration in the detection box 31 changes according to the opening and closing of the flow rate control valve 32. Then, in the state where the instantaneous gas water heater is installed at the place of use and the necessary exhaust duct 18 and the like are attached, the detection device for verification detects the average concentration of carbon monoxide in the combustion gas passing through the exhaust duct 18. Then, when the average concentration exceeds a predetermined safety standard, the opening of the flow rate control valve 32 is adjusted and fixed at that position so that the carbon monoxide concentration in the detection box 30 becomes the predetermined set value. . As a result, if the average concentration of carbon monoxide in the exhaust duct 18 exceeds a predetermined safety standard, the control device 41 operates and the solenoid valve 22
Is closed to shut off the gas supply to the gas burner 20.

According to the present embodiment as described above, the gas detection element 40 does not come to a high temperature because it comes into contact with the combustion gas in the detection box 30 whose temperature is lower than that of the high temperature combustion gas in the exhaust passage 16, Since the degree of deterioration is reduced, the durability of the gas detection element 40 is improved. Further, the opening degree of the flow rate control valve 32 is adjusted according to the error in the shape and size of the instantaneous gas water heater and the installation state, and as soon as the average concentration of carbon monoxide in the exhaust duct 18 exceeds a predetermined safety standard, the gas burner is immediately opened. Since the gas supply to 20 is cut off, errors due to differences in installation conditions are substantially eliminated.

The intake port 31 is not limited to the one directly opening to the detection box 30 as in the above-described embodiment, and the outside air may be introduced into the detection box 30 via the first communication passage 35. In addition, as in the above-described embodiment, the detection target of the gas detection element may be carbon dioxide gas instead of carbon monoxide to detect incomplete combustion, or the detection target may be oxygen or other gas component other than incomplete combustion. It can also be applied to the detection of the combustion state.

Further, the present invention is not limited to the instantaneous gas water heater as in the above embodiment, but can be widely applied to other gas water heaters or forced ventilation type gas combustion equipment using a ventilation fan such as a gas warm air heater. You can

[Brief description of drawings]

The accompanying drawings show an embodiment of an exhaust gas detection device for a gas combustion device according to the present invention. Explanation of reference numerals 10 ... Case, 16 ... Exhaust passage, 20 ... Gas burner, 25 ... Blower fan, 30 ... Detection box,
31 ... Intake hole, 32 ... Flow rate control valve, 35 ...
1st communicating path, 36 ... 2nd communicating path, 40 ... Gas detection element.

Claims (1)

[Claims] 1. A blower fan sends air into a case having a gas burner therein, and the combustion gas produced by burning the gas ejected from the gas burner by the air is passed through an exhaust passage airtightly connected to the case. In a gas combustion device that discharges to the outside, a detection box having a gas detection element inside and a detection box opened at different positions to communicate the detection box with the exhaust passage and the suction side of the blower fan, respectively. An exhaust gas detection device for a gas combustion device, comprising: a first and a second communication passage; and a semi-fixed flow control valve provided in an intake hole for introducing external air into the detection box.