JPH0714377U - Heating sensor and its installation structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an inexpensive heating type sensor that can accurately detect the CO concentration in exhaust gas and its installation structure. [Structure] CO installed on the wall of the combustion device on the exhaust path side
The entire body 1 of the sensor 15 is made of phenol resin having a thermal conductivity smaller than that of metal, and the sensor detection parts 4 and 5 of the CO sensor are arranged on the body 1. Next, a metal cover 8 obtained by pressing a metal plate is covered on the sensor detection parts 4 and 5, a plurality of mounting claws 13 are provided on the base side of the metal cover 8, and the mounting plate 7 side corresponds to the number of the mounting claws 13. The mounting hole 14 is provided, the both 13 and 14 are fitted, the claw 13 is bent, and the CO sensor 15 is mounted on the mounting plate 7. When detecting the CO concentration in the exhaust gas, the body 1 suppresses heat conduction from the wall surface 16 to the sensor detection portion, avoids adverse effects due to heat conduction, and prevents deterioration of sensor detection accuracy.
Accurately detect CO concentration.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heating sensor such as a CO sensor that detects the concentration of CO gas (carbon monoxide gas) in exhaust gas of a combustion device, a wind speed sensor that detects the supply amount of combustion air, and the installation structure thereof. Is.

[0002]

[Prior art]

 A CO sensor as a heating sensor is provided on the exhaust side of the combustion equipment such as a water heater to prevent danger due to generation of CO gas.

An example of this type of CO sensor is shown in FIG. This CO sensor 15 has two pairs of terminal pins 2 projecting from the first body 1 made of phenolic resin or the like, as shown in FIG. Through a thin platinum wire of several tens of μm, a comparison element 4 which is insensitive to CO gas and a detection element 5 which is sensitive to CO gas are provided, and the comparison element 4 and the detection element 5 are partitioned by a partition plate 6. There is. The above-mentioned comparison element 4 and detection element 5 are always heated to around 200 ° C. to form a heating type sensor.

As shown in FIG. 7, around the first body 1, a large shape formed by cutting a copper alloy such as brass is used to support and fix the first body 1. A second body 3 is provided, which is attached to the mounting plate 7. The comparison element 4 and the detection element 5 are covered with a metal cover 8. As shown in FIG. 8A, an exhaust gas conducting port 10 is formed on the peripheral wall of the metal cover 8, and the exhaust gas is formed from the conducting port 10 into the inside. .

The CO sensor 15 is arranged, for example, on the inner wall 16 of the exhaust system path of the combustion apparatus shown in FIG. When the burner 19 of the combustor burns the fuel gas, the exhaust gas is discharged from the outlet of the exhaust passage. The CO concentration in this exhaust gas is detected by the CO sensor 15, and for example, the CO concentration exceeds the standard value. In case of emergency, danger information will be output and a buzzer will be provided.

[0006]

[Problems to be solved by the device]

 By the way, since the CO sensors 15 have different temperature characteristics in the manufactured state, the CO sensors 15 are installed on the inner wall 16 after adjusting the variations in the temperature characteristics. When adjusting the variation in this temperature characteristic, for example, as shown in Fig. 10, after adjusting the temperature in the constant temperature bath to a predetermined reference temperature within the exhaust gas temperature range of 70 ° C to 220 ° C, The metal cover 8 side of the CO sensor 15 attached to the holding plate 18 is inserted into the hole of the temperature-controlled bath, and in this state, the level of the CO sensor is adjusted to the sensor level of the predetermined reference temperature. Is adjusting the output of. At this time, the bottom of the CO sensor 15, that is, the outside of the bodies 1 and 3 is almost at room temperature.

On the other hand, as shown in FIG. 9, when the CO sensor 15 is attached to the wall surface 16 of the exhaust path of the combustion device, the wall surface 16 conducts heat of the combustion gas through the frame 12 and exhaust gas. It is heated by the heat of. The heat of the wall surface 16 is transferred to the body 3 at the bottom of the CO sensor 15. Since the body 3 is made of a large cut product such as brass, it has a large heat capacity and good heat conduction, so it stores the heat from the inner wall 16 and acts as an apparent heat source, and the sensor detection unit 4, Heat transfer to 5.

FIG. 11 shows an example of the temperature characteristic of the CO sensor. When adjusting the variation of the temperature characteristic, the temperature of the constant temperature bath is set to, for example, T _0. Output level is adjusted to a reference level V ₀ corresponding to the temperature T ₀ . When this CO sensor 15 is attached to the inner wall 16 of the exhaust path, the sensor detection units 4 and 5 receive heat from the body 3 which is an apparent heat source, so that even if the temperature of the exhaust gas is T ₀ , the body 3 Due to the heat received from the side, the sensor output outputs V _1, which is higher than V ₀ , and the adjustment point is apparently confused. As described above, since the environmental condition is significantly different between when the temperature characteristic of the CO sensor 15 is adjusted and when the CO sensor 15 is attached to the exhaust passage and the combustion operation is performed, the output level with respect to the temperature is checked. The adjustment point for hanging changes. Therefore, even if the variation in the bending temperature characteristic is adjusted, the adjustment point of the output level of the CO sensor 15 apparently changes, and there is a problem that an accurate CO 2 concentration cannot be detected.

The second body 3 of the CO sensor 15 is made of a cut product such as brass and has a large volume and a large heat capacity. Therefore, the heat from the inner wall 16 is stored and the second body 3 is stored. Is transmitted to the sensor detecting units 4 and 5, the sensor detecting units 4 and 5 are affected by the heat from the second body 3 and the exhaust gas becomes less responsive to the temperature change of the gas. There was a problem.

Further, since the second body 3 is formed by cutting of brass or the like, the processing cost is high and the processing time is long, which causes a cost increase.

The present invention has been made to solve the above problems, and an object thereof is to provide an inexpensive heating sensor that can accurately detect the CO concentration in exhaust gas and its installation structure. .

[0012]

[Means for Solving the Problems]

 The present invention is configured as follows to achieve the above object. That is, according to the present invention, in a heating type sensor in which a sensor detection unit having a heating unit is installed on a body, a sensor cover is covered on the body, and the sensor detection unit is covered by the sensor cover, the body is The whole is formed of a material having a lower thermal conductivity than that of metal, and the sensor cover is configured by a press-formed product of a metal plate.

In addition, in the installation structure of the heating type sensor of the present invention, a plurality of mounting claws are projected on the base side of the metal cover in the heating type sensor, while the installation space of the heating type sensor is The wall surface is provided with mounting holes corresponding to the number of the mounting claws, and the above-mentioned mounting claws are fitted into the corresponding mounting holes and bent to directly mount the heating type sensor on the wall surface of the installation space. It is characterized by that.

[0014]

[Action]

 For example, when detecting the CO concentration in the exhaust gas of a combustion device, heat tends to be transferred from the wall surface to the sensor detection part of the CO sensor, but the entire body of the sensor is made of a material having a thermal conductivity lower than that of metal. Therefore, heat conduction to the sensor detection unit is suppressed, the adverse effect of this heat conduction is avoided, and a decrease in the detection accuracy of the CO sensor is prevented.

[0015]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals will be given to the same names as those in the conventional example, and detailed description thereof will be omitted. FIG. 1 shows the main configuration of a CO sensor as the heating type sensor of the first embodiment. In the figure, the whole body 1 in which the sensor detection section having a heating section that is constantly heated to about 200 ° C., that is, the comparison element 4 and the detection element 5 that detects the CO concentration is installed, is of the conventional type. The second body 3 is made of a material having a thermal conductivity much smaller than that of the metal such as a phenol resin. The body 1 is covered with a metal cover 8 formed by pressing a metal plate to form a thin wall.

As shown in FIG. 5, a plurality of mounting claws 13 are provided on the base side of the metal cover 8 by press working. Similarly, as shown in FIG. The mounting holes 14 corresponding to the mounting claws 13 are provided on the board 7 side, and each mounting claw 13 is fitted into the corresponding mounting hole 14 and bent, and the CO sensor 15 is mounted on the mounting board 7. There is.

Further, in the present embodiment, in order to reduce the influence of the speed change even if the exhaust gas discharge speed changes, a chamber 9 is provided in the exhaust path of the combustion device as shown in FIG. As shown in FIG. 3, the CO sensor 15 is attached to the wall surface 16 in the chamber 9.

Next, the effect of suppressing heat conduction to the sensor detection portion of the CO sensor of this embodiment will be described with reference to FIGS. 1 and 3. First, as shown in FIG. 3, when exhaust gas flows into the chamber 9 in which the CO sensor 15 is installed, the CO sensor 15 detects the CO concentration in the exhaust gas. This CO sensor 15 is shown in FIG. As described above, since the entire body 1 is formed of phenol resin having a thermal conductivity much lower than that of the metal of the conventional second body 3 or the like, the heat conducted from the frame 12 through the wall 16 of the chamber 9 is transferred. The body 1 suppresses heat conduction to the sensor detection units 4 and 5, and the heat is hardly transmitted to the sensor detection units 4 and 5. Since the environmental conditions in this usage state and the environmental conditions when adjusting the variation in the temperature characteristics of the CO sensor 15 are almost the same, the body 1 of this CO sensor 15 apparently becomes a heat source even in the usage state. Therefore, the level adjustment point will not go out of order.

Further, since the metal cover 8 is formed by pressing a metal plate to form a thin wall, the heat capacity of the metal cover 8 is small. Therefore, even if the heat from the inner wall 16 is conducted to the body 1 through the metal cover 8, the heat capacity of the metal cover 8 is small and the heat conductivity of the body 1 is small. Therefore, the body 1 does not appear to be a heat source and the heat is not transferred from the body 1 to the sensor detection units 4 and 5. In other words, since the sensor detection units 4 and 5 are hardly affected by the heat from the body 1, the CO sensor 15 quickly follows changes in the exhaust gas temperature.

According to the present embodiment, the entire body 1 in which the sensor detection units 4 and 5 having the heating unit are installed is formed of phenol resin having a heat conductivity much smaller than that of metal, and the exhaust side of the combustion device is used. When the heat from the inner wall 16 is transferred to the body 1, the body 1 suppresses the heat conduction to the sensor detection parts 4 and 5. Therefore, the environmental condition in this use condition is the temperature of the CO sensor 15. It is almost the same as the environmental condition when adjusting the variation of the characteristics, and the body 1 does not seem to be a heat source even when it is in use, and the adjustment point of the reference level is not disturbed. Further, since the metal cover 8 is formed thin, the heat capacity is small, the heat is not stored in the body 1, and the sensor detection units 4 and 5 are hardly affected by the heat from the body 1. This CO sensor 15 can quickly follow changes in the temperature of the exhaust gas. As a result, it is possible to prevent the detection accuracy of the CO sensor from decreasing.

Further, since the second body 3 formed by cutting brass or the like is unnecessary, the processing cost can be significantly reduced.

Furthermore, the mounting claw 13 is formed on the base side of the metal cover 8 by pressing, and the mounting hole 14 is also formed on the mounting plate 7 side by pressing, and the mounting claw 13 is fitted into the mounting hole 14. Since the CO sensor 15 can be attached to the mounting plate 7 simply by bending the mounting claw 13, the metal cover 8 and the mounting plate 7 can be manufactured and assembled very easily, and the cost can be greatly reduced.

Next, the CO sensor of the second embodiment and its installation structure will be described with reference to the drawings. In the CO sensor of the second embodiment, as shown in FIG. 5, the mounting plate 7 of the CO sensor 15 of the first embodiment is omitted, and the CO sensor 15 has the first embodiment. Similarly, a metal plate is press-molded to provide a plurality of mounting claws 13 on the base side of the metal cover 8. As shown in FIG. 3, the installation structure of the CO sensor 15 is such that the CO sensor 15 is directly attached to the wall surface 16 of the chamber 9 in which the CO sensor 15 is installed, or the wall surface of the exhaust path. As shown in FIG. 2, a mounting hole 14 for fitting the mounting claw 13 is provided, each mounting claw 13 is fitted into the corresponding mounting hole 14, and the mounting claw 13 is bent so that the CO sensor 15 is directly attached. This is the installation structure of the CO sensor attached to the wall surface 16.

In the second embodiment, the CO sensor 15 is directly attached to the wall 16 of the exhaust path of the combustion device by using the attachment claw 13 of the metal cover 8, so that the attachment plate 7 becomes unnecessary, Since the mounting claws 13 are simply fitted into the mounting holes 14 and then bent, the mounting work is facilitated and the cost can be significantly reduced.

The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, although the phenol resin material is used for the body 1 in the above embodiment, a ceramic material may be used instead of the phenol resin material, and if the material is a heat-resistant material having a smaller thermal conductivity than metal, The material does not matter.

Further, even if the heat resistance of the body material is slightly inferior, if the heat conductivity thereof is lower than that of metal, the material is sandwiched with, for example, a heat resistant film, and this heat resistant film is used as a heat shield layer for heat resistance. The above may be used as the body material.

Further, in the above embodiment, the metal cover 8 is provided with a circular through hole as the exhaust gas communication port 10. However, for example, as shown in FIG. Alternatively, the blade-shaped plate 11 may be cut and raised and the cut-and-raised opening 10 may be provided as shown in FIG. 5B.

Further, in the above embodiment, the contact type CO sensor has been described as an example, but of course, the present invention is also applied to a semiconductor type CO sensor having a heating portion.

Furthermore, in the above embodiment, the CO sensor was described as the heating type sensor, but the heating type sensor may be, for example, a hot wire heater type wind speed sensor that detects the supply amount of combustion air. If so, the type of sensor does not matter.

[0030]

[Effect of device]

 In the heating type sensor of the present invention, the whole body for installing the sensor detecting part equipped with the heating part is made of a material having a lower thermal conductivity than metal, and the heating type sensor is installed from the wall surface of the installation space part to the sensor detecting part. The structure that suppresses heat conduction does not cause the body to apparently become a heat source due to the heat transmitted from the inner wall of the installation space, which disturbs the reference point adjustment point of the sensor, and the metal cover has a small heat capacity. Since the body has a low thermal conductivity, a large amount of heat is not stored in the body, so the body does not act as a heat source and the heat is not transferred from the body to the sensor detection unit. The heating sensor can quickly follow changes in the temperature of the exhaust gas, for example. As a result, it is possible to prevent the detection accuracy of the heating sensor from deteriorating.

Further, since the entire body is formed of a material having a thermal conductivity lower than that of a metal, it is not necessary to cut an alloy such as brass as in the conventional case, and the processing cost can be significantly reduced.

Further, in the structure in which the metal cover is provided with the mounting claw, the mounting hole is provided in the wall surface of the installation space of the heating sensor, and the heating sensor is directly mounted on the wall surface, the mounting plate is also It becomes unnecessary and the installation work becomes easy, and the cost can be greatly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a heating type sensor of the present embodiment.

FIG. 2 is an explanatory diagram of a mounting plate of the heating sensor according to the present embodiment.

FIG. 3 is an explanatory diagram of a chamber in which the heating sensor according to the present embodiment is installed.

FIG. 4 is an explanatory diagram in which a chamber is provided in an exhaust path of a combustion device.

FIG. 5 is an explanatory diagram of a heating type sensor according to a second embodiment.

FIG. 6 is an explanatory diagram of a heating type sensor having another configuration.

FIG. 7 is an explanatory diagram of a conventional CO sensor.

FIG. 8 is an explanatory diagram of a main part configuration of a conventional CO sensor.

FIG. 9 is an explanatory diagram showing a state in which a conventional CO sensor is installed in an exhaust path of a combustion device.

FIG. 10 is an explanatory diagram of an example of adjusting variations in temperature characteristics of a CO sensor.

FIG. 11 is an explanatory diagram of temperature characteristics of a CO sensor.

[Explanation of symbols]

 1 1st body 3 2nd body 4 Comparison element 5 Detection element 7 Mounting plate 8 Metal cover 9 Chamber 13 Mounting claw 14 Mounting hole 15 Heating sensor 16 Chamber wall

Claims (2)

[Scope of utility model registration request] 1. A heating type sensor in which a sensor detection unit including a heating unit is installed on a body, and a sensor cover is covered on the body so that the sensor detection unit is covered by the sensor cover. A heating type sensor, wherein the whole is made of a material having a thermal conductivity smaller than that of metal, and the sensor cover is made of a press-formed product of a metal plate. 2. The heating sensor according to claim 1, wherein a plurality of mounting claws are projected on the base side of the metal cover, while the number of the mounting claws is provided on the wall surface of the installation space of the heating sensor. A mounting structure for a heating sensor, in which mounting holes corresponding to the mounting holes are provided, the mounting claws are fitted into the corresponding mounting holes, and the heating sensors are directly mounted on the wall surface of the mounting space.