JPH08170826A - Gas water heater - Google Patents

Abstract

PURPOSE: To provide a gas water heater, having a CO sensor capable of monitoring directly the concentration of carbon monoxide in a gas water heater installing chamber without receiving any affection of the temperature or the constituents of exhaust gas, different in accordance with the various using condition of the water heater. CONSTITUTION: An air filter 51 is attached to the combustion air supplying port 29 of a gas water heater 1 while a CO sensor 53 is attached to the inside of the air filter 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas water heater equipped with a CO sensor, and more particularly to a gas water heater for indoor installation which can effectively exhibit the function of the CO sensor.

[0002]

2. Description of the Related Art The prior art will be described by taking an open type gas water heater for home use as an example. FIG. 2 shows the internal structure of a conventional home-use open type gas water heater.

This water heater 1 has a case 3 surrounding the outside of the entire apparatus, a heat exchanger 5 arranged in the upper part of the apparatus, and a plurality of gas burners arranged below the heat exchanger 5. 7, a water flow rate control device 9 for controlling the flow rate of water, which is an object to be heated, supplied to the heat exchanger 5, and a gas burner 7
A gas flow controller 11 for controlling the amount of gas supplied to
A combustion chamber opening temperature sensor 13 that is provided in the opening 12 of the combustion chamber inner wall to detect the ambient temperature in the opening 12 and a pilot flame temperature sensor 1 that detects the temperature of the pilot flame emerging from the pilot burner 27.
5, and the water flow rate control device 9 and the gas flow rate control device 11 based on the temperature signals detected by the two temperature sensors 13 and 15.
And a control unit 17 that controls the above.

Such a water heater 1 is installed in a kitchen or other room of a general household and operates as follows.

City gas is supplied to the gas burner 7 through a gas passage 19 and a gas chamber 21. The gas passage 19 is provided with a manual gas shutoff valve 23 used for repairs and the like, and an automatic gas shutoff valve 25 that automatically shuts off the gas passage 19 in an emergency. The flow rate of the gas flowing through the gas flow path 19 is controlled to an appropriate flow rate by the gas flow rate control device 11.

In the vicinity of the gas outlet of the gas burner 7, the pilot burner 2 is directed toward the gas outlet.
7 are arranged, and the pilot flame emitted from the pilot burner 27 ignites the gas ejected from each gas burner 7.

An air supply port 29 is opened on the bottom surface of the case 3, and city gas is burned in the gas burner 7 by the air supplied through the air supply port 29 to the inside of the apparatus.

The heat exchanger 5 arranged above the gas burner 7 is provided with a heat transfer tube 31 which is arranged above the gas burner 7 so as to meander in a U-shape. The tap water is flowing through the water pipe 33. The amount of tap water flowing through the water pipe 33 is adjusted by the water flow rate control device 9. The water pipe 33 is provided with a manual water shutoff valve 35, and when necessary, the water shutoff valve 35 can be manually closed to stop the supply of tap water to the water pipe 33. There is.

The tap water flowing through the water pipe 33 is heated by the radiant heat of the flame of the city gas emitted from each gas burner 7 and the heat of the combustion gas, and is discharged as hot water.

The heat exchanger 5 has a large number of fins 37 formed outside the heat transfer tube 31. This fin 3
7 extends parallel to the flow path of the combustion gas emitted from each gas burner 7, and the spacing between the fins 37 is, for example, about 3 mm. The fin 37 is generally made of a lead-plated copper plate, and has a function of efficiently transmitting the flame radiation heat and the sensible heat of the combustion gas to the water pipe 33.

The two temperature sensors 13 and 15 each consist of a thermocouple, and generate thermoelectromotive force (voltage) corresponding to the temperature detected by each. Combustion chamber opening temperature sensor 1
The thermoelectromotive force generated corresponding to the temperature of the combustion chamber opening 12 detected by 3 and the temperature of the pilot flame detected by the pilot flame temperature sensor 15 are signal lines 39, 4
It is taken out via 1. These two signal lines 39, 41
Are connected in series in such a direction that the polarities of the thermoelectromotive forces generated by the two sensors 13 and 15 are mutually canceled and canceled.
In the present gas water heater 1, the control unit 17 detects the difference in thermoelectromotive force between the two sensors 13 and 15, and controls the water flow rate control device 9 and the gas flow rate control device 11 according to the difference, It prevents the occurrence of incomplete combustion.

An exhaust port 43 is provided on the upper surface of the case 3, and an exhaust duct 45 is connected to the exhaust port 43. The combustion gas generated from each gas burner 7 exchanges heat with the heat exchanger 5, and then the exhaust port 4 of the case 3
3 is exhausted to the outside of the gas water heater 1 as exhaust gas through the exhaust duct 45. The exhaust duct 45 is formed to meander in order to reduce the momentum of the exhaust gas. That is, the exhaust gas exiting the exhaust port 43 of the case 3 once bends to the left, then rises, turns to the right, rises again, and is discharged to the outside of the case 3.

At the position where the exhaust gas starts to rise again, C
An O sensor 47 is arranged. This CO sensor 47 detects the concentration of carbon monoxide (CO) gas in the exhaust gas,
If the concentration exceeds a predetermined threshold,
A signal to that effect is issued to the gas flow control device 11. Upon receiving this signal, the gas flow control device 11 immediately closes the automatic gas cutoff valve 25 and stops the combustion of city gas in each gas burner 7. Then, a display panel (not shown) is displayed to that effect and the user is alerted.

[0014]

However, since the CO sensor 47 in the above-described conventional gas water heater 1 is attached to the exhaust duct 45, that is, the flow path of the exhaust gas, it has the following problems. It was

(1) In general, the CO sensor 47 is not so high in heat resistance that it may not be able to accurately detect the concentration of carbon monoxide gas under high temperature. At the mounting position of the CO sensor 47 as shown in FIG. 2,
Although the temperature of the exhaust gas has dropped considerably, if the gas water heater 1 is used at its maximum capacity for a long time, the temperature of the exhaust gas will rise considerably, and for example, the temperature at the same position will be the maximum. It reaches about 100 ° C. Therefore, in such a case, the detection accuracy of the CO sensor 47 may decrease. In addition, when exposed to high temperature for a long time, CO
There is also a fear that the life of the sensor 47 may be shortened.

(2) Naturally, the CO sensor 47
In order to detect only carbon monoxide gas, it is necessary to set high sensitivity to carbon monoxide gas and low sensitivity to other gases. The sensitivity of the CO sensor 47 is
Generally, the concentration is set based on the concentration of the assay gas having a certain specific component. However, in general, a water heater has various combustion modes, but it is known that the components of the exhaust gas (for example, SOx and water vapor) greatly change depending on the combustion mode. For this reason, if the components of the exhaust gas are significantly different from the components of the above-mentioned calibration gas, the sensitivity of the CO sensor 47 to the carbon monoxide gas may be adversely affected in some cases.

Originally, the CO sensor is intended to enhance the safety inside the gas water heater installation room. Since the carbon monoxide concentration in the gas water heater installation room greatly changes depending on the size of the room or the degree of ventilation, as in the gas water heater 1 shown in FIG. When mounted on a road, the sensitivity of the CO sensor 47 is affected by the components of the exhaust gas, and it was extremely difficult to achieve the original purpose of the CO sensor, that is, the detection of the concentration of carbon monoxide gas in the indoor atmosphere.

The present invention has been made in view of the above problems of the conventional CO sensor, and is influenced by the temperature of the exhaust gas or the components of the exhaust gas which differ depending on various usage conditions of the gas water heater. An object of the present invention is to provide a gas water heater having a CO sensor that can directly monitor the carbon monoxide concentration in the gas water heater installation chamber without receiving the gas.

[0019]

In order to achieve the above object, a gas water heater according to the present invention transfers a heat quantity of combustion gas generated in the combustion apparatus to the water to be heated. A gas water heater having a heat exchanger, wherein the gas water heater includes a CO sensor, and the CO sensor is in the vicinity of an air supply port for introducing combustion air into the gas water heater. It is characterized by being arranged.

[0020]

In this gas water heater, the CO sensor is arranged near the combustion air supply port. Since this combustion air supply port is a place through which the air in the room directly passes, high temperature gas such as exhaust gas does not pass. For this reason, the CO sensor operates at room temperature without being exposed to high temperatures, and more accurate CO concentration detection becomes possible. In addition to this, it is possible to prevent a decrease in life due to operation at high temperature for a long time.

Further, since the exhaust gas containing SOx, water vapor, etc. exhausted from the exhaust port is diluted by the indoor atmosphere, SOx in the air passing through the combustion air supply port.
The concentration of CO and water vapor is extremely low, and the sensitivity of the CO sensor is not affected. Therefore, the CO sensor is S
Since it is not affected by miscellaneous gas components such as Ox and water vapor, high sensitivity to carbon monoxide gas can be maintained. Further, by directly monitoring the concentration of carbon monoxide in the gas water heater installation room, the original purpose as a safety device, that is, ensuring safety in the room, is achieved.

[0022]

1 shows a first embodiment of a gas water heater according to the present invention. In FIG. 1, the parts designated by the same reference numerals as those in FIG. 2 indicate the same or similar components as the components in FIG.

In the gas water heater 1 according to this embodiment,
Combustion air supply port 29 provided on the bottom surface of the case 3
An air filter 51 is attached to the. In this gas water heater, a CO sensor 53 is attached inside the air filter 51. In the conventional gas water heater, the exhaust duct 45 was provided with a CO sensor.

The air filter 51 is generally used and is for preventing relatively large dust and dirt from entering the inside of the gas water heater 1.

The air in the room is introduced into the gas water heater 1 through the combustion air supply port 29. Generally, since the maximum room temperature is about 35 ° C, the temperature of the indoor air is also about 35 ° C at the maximum. On the other hand, inside the exhaust duct 45 shown in FIG. 2, a maximum temperature of about 100 ° C. may be reached depending on the combustion mode of the gas water heater 1. Therefore, CO in conventional gas water heaters
Although the sensor 47 may be affected by the high temperature and the detection accuracy may be reduced, in the present embodiment, the CO sensor 53 is used.
Operates at a temperature of about 35 ° C., which is the same temperature as room air at the maximum. Therefore, the CO concentration can be detected more accurately without being adversely affected by the high temperature.

In addition, since the concentration of the miscellaneous gas components such as SOx and water vapor discharged from the gas water heater 1 is diluted, the air in the room where the gas water heater is installed is used for combustion into which the room air flows. The CO sensor 53, which is arranged in the vicinity of the air supply port 29, can operate without being affected by the miscellaneous gas components. In addition, the concentration of carbon monoxide in the gas water heater installation room can be directly monitored, and CO
It is also preferable in achieving the original purpose of the sensor (ensuring safety in the room).

In this embodiment, the CO sensor 5
3 is arranged near the combustion air supply port 29,
If the position is between the air supply port 29 and the gas chamber 21, the degree of influence of the temperature due to the combustion of each gas burner 7 is small and it is not affected by the miscellaneous gas components. Can be placed at. For example, the outside of the gas flow control device 11 or the gas chamber 21
It is also possible to attach the CO sensor 53 to the bottom surface of the CO water heater, and it is possible to increase the degree of freedom of the mounting position of the CO sensor 53 when designing the gas water heater.

Also in this embodiment, as in the case of the CO sensor 47 shown in FIG. 2, when the CO sensor 53 is connected to an alarm device (not shown) and the carbon monoxide concentration exceeds a predetermined threshold value. In this case, a warning signal can be issued to the alarm device and an alarm can be issued from the alarm device.

Alternatively, the CO sensor 53 is connected to the control unit 17 via the signal line 55, and when the CO sensor 53 detects the carbon monoxide concentration, the CO concentration signal corresponding to the concentration is transmitted to the control unit 17. It can also be configured to do so.

Upon receiving the CO concentration signal from the CO sensor 53, the controller 17 receives the C concentration represented by the CO concentration signal.
The O concentration is compared with a predetermined threshold value. If the CO concentration represented by the CO concentration signal is smaller than a predetermined threshold value, it is determined that combustion is normally performed in each gas burner 7, and combustion in each gas burner 7 is continued.

On the other hand, when the CO concentration represented by the CO concentration signal exceeds a predetermined threshold value, incomplete combustion occurs in each gas burner 7, and the gas is released due to the incomplete combustion. Due to carbon oxide, it is determined that the CO concentration in the room is high, and a gas flow stop signal is sent to the gas flow rate control device 11. Upon receiving the gas flow stop signal, the gas flow control device 11 closes the automatic gas cutoff valve 25 to stop the combustion of each gas burner 7.

[0032]

As described above, in the gas water heater according to the present invention, since the CO sensor is arranged near the combustion air supply port through which the air in the room passes, it is exposed to the high temperature due to the exhaust gas. Operation is performed at room temperature without being affected, and more accurate CO concentration detection becomes possible. It is also possible to prevent the life of the CO sensor from being shortened due to long-term operation at high temperature.

In addition, since the miscellaneous gas components such as SOx and water vapor are already diluted in the air introduced from the combustion air supply port, their concentrations are extremely low and the sensitivity of the CO sensor is high. Has little effect on.
Therefore, the CO sensor is less likely to be affected by miscellaneous gas components such as SOx and water vapor. It is also preferable in order to achieve the original purpose of installing the CO sensor, which is to directly monitor the carbon monoxide concentration in the gas water heater installation room.

[Brief description of drawings]

FIG. 1 is a schematic view showing an internal structure of a conventional home-use open-type gas water heater.

FIG. 2 is a schematic view illustrating a heating device according to an embodiment of the present invention as an open type gas water heater for home use.

[Explanation of symbols]

1 Water Heater 3 Case 5 Heat Exchanger 7 Gas Burner 9 Water Flow Control Device 11 Gas Flow Control Device 12 Combustion Chamber Wall Opening 13 Combustion Chamber Opening Temperature Sensor 15 Pilot Flame Temperature Sensor 17 Control 19 Gas Flow 21 Gas Chamber 23 Gas shutoff valve 25 Automatic gas shutoff valve 27 Pilot burner 29 Combustion air air inlet 31 Heat transfer tube 33 Water tube 35 Water flow control valve 37 Fin 39 Signal line 41 Signal line 43 Exhaust port 45 Exhaust duct 47 CO sensor 51 Air filter 53 CO sensor 55 signal line

Claims (1)

[Claims] 1. A gas water heater having a combustion device and a heat exchanger for transmitting the heat quantity of the combustion gas generated in the combustion device to water, which is an object to be heated, wherein the gas water heater is CO. A gas water heater comprising a sensor, wherein the CO sensor is arranged in the vicinity of an air supply port for introducing combustion air into the gas water heater.