JP2999885B2 - Gas sensor and inspection method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a gas sensor such as a catalytic combustion type or a semiconductor type in which a gas sensitive body is used at a temperature higher than room temperature.

[0002]

2. Description of the Related Art FIG.
Is shown in Such a gas sensor is provided with a gas sensitive body in an explosion-proof container. Referring to the specific example shown in FIG. 3, an explosion-proof container includes a sensor base 1, a metal pipe 2 mounted on the sensor base 1,
The explosion-proof wire mesh 3 is provided at the head of the metal pipe 2, and the above-described explosion-proof wire mesh 3 is configured as a gas flow section through which a gas to be detected can flow between the internal space and the surrounding environment.

[0003]

The problems of the conventional gas sensor will be described below. (1) The performance of a catalytic combustion type or semiconductor type gas sensor is generally strongly affected by the surface temperature of a gas sensitive body. Conventionally, such surface temperature management of a sensitive body in a manufacturing process for producing a plurality of gas sensors has been performed by an indirect method such as individually managing power consumption of the sensitive body. However, in this method, since the surface temperature management is an indirect verification, it is not possible to make the surface temperature of the sensitive body of all products the same, and it is sometimes difficult to obtain a sensor with uniform characteristics. . (2) The gas sensor has a structure in which a high-temperature sensitive body is surrounded by a fine-grained stainless steel wire mesh permeable portion or an opaque metal protection portion in order to satisfy explosion-proof requirements.
However, it is difficult to see through the air permeable part as well as the metal protection part because of the fine mesh of the wire mesh. It is not possible to visually check the state of the gas sensitive body attached to the pin), the temperature inside the sensor (the temperature of the gas sensitive body, the ambient temperature of the gas sensitive body, etc.), etc. In some cases, it was difficult to obtain a sensor having the same characteristics. Accordingly, an object of the present invention is to provide a gas sensor having a sensor structure capable of easily managing the surface temperature and the like of a gas sensitive body and obtaining a gas sensor having good characteristics and uniform characteristics.

[0004]

Means for Solving the Problems The detection of the gas sensor of the present invention is performed.
The characteristic configuration of the inspection method is formed in an explosion-proof
Sensitivity to gas to be detected by energizing
A gas sensitive body having
Between the gas distribution unit through which the gas to be detected can flow
When inspecting a gas sensor having a
With the body energized, formed on the wall of the explosion-proof container
At least one of infrared light and visible light can be transmitted
Measure the transmitted light passing through the inspection window and measure the gas sensitivity.
Inspecting the body, wherein the inspection wall is a transparent glass
, Transparent plastic, flint glass, quartz, fluoride
At least selected from calcium and chalcogen glass
It is preferable to be formed from a kind of material. Further
In addition, a gas sensor suitable for performing such an inspection method
The characteristic configuration of the internal formed in the explosion-proof container of the explosion-proof configuration
Sensitivity to the gas to be detected by energizing the space
A gas sensitive body between the internal space and the surrounding environment.
A gas distribution unit through which the gas to be detected can flow,
Clear glass, transparent plastic on the wall of the explosion-proof container
, Flint glass, quartz, calcium fluoride, calco
Formed from at least one material selected from genglass
And at least one of infrared light and visible light is transmitted
Infrared or visible light is formed in a possible inspection window
The point is that the inside is formed so as to be inspectable by transmitting light.

[0005]

In other words, since infrared rays or visible rays are transmitted through the inspection window, the gas sensor can grasp its internal state from the outside. That is, for example,
If infrared radiation is provided an inspection window capable of transmitting the infrared coming out sensor to detect an infrared radiation thermometer, passing
Is Rukoto obtain a surface temperature of the gas sensitive body in conductive state
In this case, the quality of the product can be appropriately determined based on the surface temperature. On the other hand, in the case of visible light, an operator can visually check the mounting state of the gas sensitive body, the surface temperature state during operation, and the like from the outside , and judge the quality of the product from the state . Specifically, clear glass, transparent plastic
Is transparent to visible light, and flint glass is ~ 2.5
Infrared and calcium fluoride up to 10 μm
Infrared, quartz (or quartz glass)
Has a transmissive wavelength that transmits infrared light at
Various types of lass), visible light and infrared light
Is easily set to a high value, and an appropriate judgment can be easily made.

[0006]

Accordingly, it is possible to easily detect the position, color, surface temperature, etc. of the gas sensing element from the outside of the sensor to perform quality control, and to supply a gas sensor having uniform characteristics. Now you can. Further, in a gas sensor having such a sensor structure, even in a process other than the manufacturing process, for example, when it is necessary to investigate the condition inside the sensor and the temperature of the sensitive body, such as when a claim occurs, It is not necessary to disassemble the strong explosion-proof container (not only troublesome but also often accompanied by damage to the internal structure of the sensor).

[0007]

An embodiment of the present invention will be described with reference to the drawings. The configuration of the sensor shown in FIG. 1 is the same as that of the conventional one, and a sensor base 1 formed of resin or opaque glass,
An explosion-proof container 4 is provided with a pipe 2 mounted on the sensor base 1 and an explosion-proof wire net 3 provided at the head of the pipe 2. As described above, the explosion-proof wire mesh 3 is configured as a gas distribution unit through which the gas a to be detected can flow between the internal space 5 and the surrounding environment 6. Further, a sensor electrode pin 7 is provided on the sensor base 1, and a gas-sensitive body 8 of a contact combustion type or a semiconductor type is provided at the tip of the pin 7. By adopting this configuration, the gas a to be inspected flows into the gas sensor from the explosion-proof wire mesh 3 and is detected by the gas sensing element 8.

Now, the characteristic configuration of this gas sensor will be described. In this gas sensor, the pipe 2
Is made of quartz glass which is an infrared transmitting material,
In the operating state of the gas sensor, infrared rays b radiated from the surface temperature of the gas sensitive body 8 which is relatively high
Through. Then, a configuration is adopted in which the infrared ray b is detected by an infrared radiation thermometer (not shown) and the temperature of the gas sensitive body surface can be measured. Therefore, this pipe 2 becomes the inspection window 9.

Hereinafter, the manufacturing process of the gas sensor and the inspection process thereof will be described. [Manufacturing process] 1. The sensor electrode pins 7 are set up on the sensor base 1. 2. A coil 8a constituting a part of the gas sensitive body 8 is attached across the sensor electrode pin 7. 3. A semiconductor 8b is attached to the periphery of the coil 8a. 4. A pipe 2 provided with an explosion-proof wire mesh 3 is attached to a sensor base 1. Through the above steps, the tentative production of the gas sensor is completed.

[Quality Inspection] The following inspection is performed with the gas sensor energized. 1. Measurement of power consumption (conventionally performed). 2. The infrared radiation b passing through the pipe 2 is measured by an infrared radiation thermometer, and the surface temperature of the gas sensitive body surface is measured. 3. Further, the sensor output is inspected at a predetermined concentration of the gas to be detected. From the results measured in this way, only those gas sensors that pass the standard are selected.

[Other Embodiments] Another embodiment of the present invention will be described below. 1. In the above embodiment, an example is shown in which the sensor base 1 is provided with the explosion-proof wire mesh 3 and the pipe 2 as an internal inspection window is erected, but as shown in FIGS. It is also possible to employ a simple configuration. Hereinafter, each will be described separately. (A) The pipe 2 is a metal pipe having a conventional configuration, and the inspection base 9 is formed in the sensor base 1. (B) The explosion-proof wire mesh 3 is formed into a pipe shape, and the ceiling is configured as an inspection window 9. (C) The explosion-proof wire mesh 3 is formed in the shape of a dome and is erected on the sensor base 1.
What formed. (D) The inspection window 9 is formed in a dome shape and is erected on the sensor base 1, and the explosion-proof wire mesh 3 is formed on the sensor base 1.

2. Further, in the above embodiment, the pipe 2 is formed of a quartz glass material, but may be formed of the following material. (A) Visible light transmission material Glass, transparent plastic material, etc. When such a material is used, the inside of the gas sensor can be visually inspected and the Since the color of the surface can also be confirmed, it is possible to detect the assembled state of the gas sensitive body, the surface temperature, and the like. (B) Materials for Infrared Transmission Materials Flint glass, quartz, calcium fluoride, various infrared transmitting glasses (such as chalcogen glass), etc. The transmission wavelengths of the above materials are as follows. <Transmission wavelength> Flint glass: Up to 2.5 μm Calcium fluoride: Up to 10 μm Quartz: Up to 4 μm (or quartz glass)

3. In the above-described embodiment, an example in which the present invention is applied to a sensor having two terminals as a sensor shape has been described. However, the present invention can be applied to any type of sensor such as a three-terminal or four-terminal sensor.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a gas detector.

FIG. 2 is a diagram showing a configuration of another embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a gas detector having a conventional configuration.

[Explanation of symbols]

 4 Explosion-proof container 5 Internal space 6 Ambient environment 8 Gas sensitive body 9 Inspection window a Gas

Claims (3)

(57) [Claims] An explosion-proof container (4) formed in an explosion-proof configuration.
In the internal space (5), the gas to be detected (a)
A gas sensitive body (8) having sensitivity to
The object to be detected between the internal space (5) and the surrounding environment (6)
Having a gas distribution section (3) through which the gas (a) can flow.
This is a gas sensor inspection method for inspecting natural gas sensors.
The explosion-proof container while the gas sensing element (8) is energized.
(4) The amount of infrared or visible light formed on the wall
At least one is transmitted through the inspection window (9) that can be transmitted.
Gas sensor for measuring the transmitted light
Inspection method of sa. 2. The inspection wall (9) is made of transparent glass,
Transparent plastic, flint glass, quartz, calcium fluoride
At least one selected from the group consisting of calcium and chalcogen glass
2. The gas sensor according to claim 1, wherein the gas sensor is made of a material.
Inspection method. 3. A gas (a) to be detected is supplied to an internal space (5) formed in an explosion-proof container (4) having an explosion-proof configuration by energization.
A gas sensible body (8) having sensitivity to the gas, and a gas circulating section (3) through which the gas (a) to be detected can flow between the internal space (5) and the surrounding environment (6). ), Wherein the explosion-proof container (4) has a transparent glass, a transparent plastic, a flint glass,
Selected from quartz, calcium fluoride, chalcogen glass
Formed from at least one material,
Inspection window that can transmit at least one of visible light
Formed in (9) and transmit infrared or visible light
A gas sensor whose inside can be inspected freely .