JPH01107014A - Exhaust gas detector for gas burner - Google Patents

Abstract

PURPOSE:To detect the composition of combustion gas not accompanied by errors produced by a change in the installation condition of equipment by providing a detection box equipped with a gas detection element inside, a first communication passage, a second communication passage, and a flow rate control valve. CONSTITUTION:A negative pressure produced on the intake side of a blower 25 forces an air present in a detection box 30 to be sucked up through a second passage 36. Responding, with this, a high temperature combustion gas in an exhaust passage 16, which is sucked up through a first passage 35, an ambient temperature outside air, which is sucked up through an intake nozzle 31, are mixed inside the detection box 30 and become colder than a combustion gas inside the exhaust passage 16. The composition of the gas to be detected is detected by a gas detection element 42. An attempt is made to adjust and fix a flow rate control valve 32 so that the concentration of the gas composition to be detected inside the detection box 30 may conform to a specified value when the average concentration of gas present inside the exhaust passage 16, which must be detected, indicates a specified value. This construction makes it possible to detect the average concentration of the gas composition to be detected inside the exhaust passage 16 at a high value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust gas detection device used for detecting the combustion state of gas combustion equipment.

(Prior art) Air is sent from a blower fan into a case in which a gas burner is installed, and the air is used to combust gas ejected from the gas burner, and the resulting combustion gas is discharged to the outside through an exhaust passage airtightly connected to the case. BACKGROUND ART Some gas combustion devices that emit gas are equipped with a gas detection element in an exhaust passage to detect a combustion state such as incomplete combustion, and thereby control the operation of the device.

(Problems to be Solved by the Invention) This type of exhaust gas detection device has a problem in that since the gas detection element is provided in the exhaust passage, the gas detection element is easily exposed to high temperatures and deteriorates, resulting in poor durability. There is. Furthermore, since the gas components in the exhaust passage differ from place to place, it is not possible to detect the average composition of combustion gas, and the equipment conditions of the equipment, including errors in the shape and size of individual equipment and the shape of the exhaust duct, etc. If the flow in the exhaust passage changes due to this, the gas components at the location where the gas detection element is installed will also change slightly, resulting in a problem of increased detection variation and decreased detection accuracy. The present invention attempts to solve each of these problems.

(Means for Solving the Problems) For this purpose, the exhaust gas detection device for gas combustion equipment according to the present invention has a gas burner 20 installed inside, as illustrated in the attached drawings.
A blower fan 25 blows air into the case 10 provided with the gas burner 20, and the combustion gas generated by combusting the gas ejected from the gas burner 20 is discharged to the outside through an exhaust path 1816 airtightly connected to the case 10. In the gas combustion equipment, there is a detection box 30 equipped with a gas detection element 40 inside, and a detection box 30 at different positions.
first and second communication passages 35 and 36 that are open to the detection box and communicate with the exhaust passage 16 and the suction side of the blower fan 25, respectively; and an intake hole 31 that introduces external air into the detection box 30. It is characterized by being equipped with a semi-fixed flow rate control valve 32 provided at the.

(Function) Due to the negative pressure generated on the suction side of the blower fan 25 during operation of the gas combustion equipment, the gas in the detection box 3o is sucked through the second passage 36, and accordingly, the gas is sucked through the first passage 35. The high temperature combustion gas in the exhaust passage 16 and the ambient temperature outside air taken in through the intake port 31 are mixed in the detection box 30 and become lower temperature than the combustion gas in the exhaust passage 16.
The gas component to be detected therein is detected by the gas detection element 4o. Therefore, when the gas combustion equipment is installed at each usage location, the detection box 3
The flow control valve 32 is adjusted and fixed so that the concentration of the gas component to be detected within 0 becomes a predetermined set value. As a result, the gas detection element 40 detects the gas component in the detection box 30, thereby detecting the average concentration of the gas component to be detected in the exhaust passage 16 with high accuracy.

(Effects of the Invention) As described above, according to the present invention, the gas detection element is not directly exposed to high-temperature combustion gas in the exhaust passage, but is mixed with air taken in from the intake port in the detection box, and the temperature increases. Since the gas detection element only comes into contact with the combustion gas whose temperature has been reduced, the temperature does not become so high that the durability of the gas detection element can be improved. In addition, the gas detection element can be adjusted after installation to detect the average concentration of gas components in the exhaust passage, so it is possible to adjust it after installation to detect the average concentration of gas components in the exhaust passage. The components of combustion gas can be detected without errors caused by changes.

(Example) 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 instantaneous gas water heater has an inner shell 1.
Combustion air is supplied from a blower fan 25 attached to the bottom of the outer shell 12.
Through the passage formed between 1.12 and the partition plate 13,
It flows into the inner shell 11 from the lower side. A fin-tube heat exchanger 15 and an exhaust passage 16 consisting of an exhaust hood 17 and an exhaust duct 18 are airtightly connected to the upper side of the inner shell 11, and a gas burner 20 is provided in the lower part of the inner shell 11. . Gas supplied through the gas passage 21 and ejected from the gas burner 20 is combusted within the inner shell 11 by combustion air from the blower fan 25, and the resulting high-temperature combustion gas is blown into the water pipe 15a of the heat exchanger 15. heats the water flowing through the
It is discharged indoors or outdoors through the exhaust passage 16. The gas passage 211 includes a solenoid valve 22 and a gas amount adjustment valve (described later).
(not shown) is provided.

A gas detection element 40 for detecting harmful components such as -carbon oxide is provided inside the detection box 30, which is a main part of the present invention.
As shown in the drawing, its upper part communicates with the inside of the exhaust hood 17 via the first communicating passage 25, and its lower part communicates with the inside of the exhaust hood 17 through the first communicating passage 25.
It is communicated with the inside of the suction port 26 of the ventilation fan 25 via. Further, the detection box 30 is provided with an intake hole 31 that communicates with the outside air, and this intake hole 31 has a semi-fixed flow rate control valve 3.
2 is provided. The opening degree of the flow rate control valve 32 is manually adjusted and then maintained at that opening degree, and the detection box 3 is
A butterfly valve is used in this embodiment, but a gate valve or a needle valve may also be used. The control device 41 includes a gas detection element 40
When the concentration of carbon monoxide in the detection box 30 detected by
This is to cut off the gas supply to the

While the instantaneous gas water heater is in operation, the blower fan 25 is in operation, and a predetermined negative pressure is generated at a position within the suction port 26 where the tip of the second communication passage 36 is closed. This negative pressure causes the detection box 3 to
The gas inside the exhaust hood 17 is sucked into the blower fan 25 at a constant rate, and the high-temperature combustion gas inside the exhaust hood 17 and the outside air enter the detection box 30 through the first communication path 35 and the intake hole 31, respectively. The gas is sucked in and mixed, and its temperature becomes lower than the temperature of the combustion gas in the exhaust hood 17, and the concentration of carbon monoxide therein is detected by the gas detection element 40. The carbon monoxide concentration within this detection box 31 changes according to the opening and closing of the flow control valve 32. Therefore, when the instantaneous gas water heater is installed at the place where it is used and the necessary exhaust duct 18 etc. are attached, the average concentration of carbon monoxide in the combustion gas passing through the exhaust duct 18 is detected by the verification detection device. Then, when this average concentration exceeds a predetermined safety standard, the opening degree of the flow control valve 32 is adjusted and fixed at that position so that the carbon monoxide concentration in the detection box 30 reaches 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 is activated, and the solenoid valve 22 is activated.
is closed to cut off the gas supply to the gas burner 20.

According to this embodiment, the gas detection element 40 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, so the temperature does not reach that high. 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 shape and size error of the instantaneous gas water heater and the installation condition, and if the average concentration of carbon monoxide in the exhaust duct 18 exceeds a predetermined safety standard, the gas burner Since the gas supply to 20 is cut off, errors due to differences in installation conditions are substantially eliminated.

Note that the intake port 31 is not limited to the one that opens directly into the detection box 30 as in the above embodiment, but may introduce outside air into the detection box 30 via the first communication path 35. In addition, as in the above embodiment, incomplete combustion can be detected by using carbon dioxide as the detection target of the gas detection element instead of carbon monoxide, or by using other gas components such as oxygen as the detection target to detect incomplete combustion. It can also be applied to detecting combustion conditions.

Further, the present invention is widely applicable to forced draft gas combustion equipment using a blower fan such as the above embodiment (not limited to instantaneous gas water heaters, but other gas water heaters or gas hot air heaters). be able to.

[Brief explanation of the drawing]

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

Claims (1)

[Claims] Air is sent from a blower fan into a case with a gas burner inside, and the air is used to combust the gas ejected from the gas burner, and the resulting combustion gas is discharged to the outside through an exhaust passage airtightly connected to the case. The combustion equipment includes a detection box having a gas detection element therein, and first and second first and second detection boxes that open into the detection box at different positions and communicate the detection box with the exhaust passage and the suction side of the blower fan, respectively. 1. An exhaust gas detection device for gas combustion equipment, comprising a communication path and a semi-fixed flow rate control valve provided in an intake hole for introducing outside air into the detection box.