Gas sensor

Abstract

The utility model discloses a gas sensor which comprises a main body structure (1), a measuring range adjusting disc (2) and a gas sensitive component (5), a cavity (10) is arranged in the main body structure (1), the gas sensitive component (5) is arranged in the cavity (10), a main gas inlet (8) is further arranged on the main body structure (1), and the cavity (10) is communicated with the outside through the main gas inlet (8). A plurality of gas limiting holes (7) with different apertures corresponding to a plurality of ranges are formed in the range adjusting disc (2) in a penetrating manner, the range adjusting disc (2) is arranged above the main body structure (1), and the range adjusting disc (2) is shifted until the gas limiting hole (7) with the required range is positioned right above the main gas inlet (8) and then is detachably mounted and fixed with the main body structure (1); therefore, the detection range of a single gas sensor can be adjusted, the application cost of the sensor in the field of gas concentration detection is reduced, and design and application of a matched circuit or detection equipment are facilitated.

Description

Technical Field

[0001] The utility model relates to the field of sensors, in particular to a gas sensor. Background Art

[0002] With the development of the times, the Internet of Things (IoT), where everything is connected, is increasingly affecting people's lives. The IoT uses sensors based on various principles as the perception layer to obtain underlying information. The indicators detected by these sensors can be physical quantities or chemical quantities, and they serve as the eyes and tentacles of the IoT to provide basic data for the IoT. The IoT has been increasingly used in all levels of production and life. For example, the content of toxic and harmful gases in crowded places such as factories, mining, hospitals, and schools is closely related to people's lives and property. The centralized monitoring of the IoT and big data can play a good early warning role. Among various gas sensors, gas sensors based on electrochemical principles are widely used due to their advantages such as rapid response, high cost performance, strong robustness, and friendly to environmental temperature and humidity.

[0003] At present, in practical applications, electrochemical gas sensors need to use gas sensors with different ranges to detect different concentration ranges of the same gas. Using them beyond the range will cause inaccurate readings or even damage the sensor. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a gas sensor to address the defect of the prior art that gas sensors with different ranges need to be used to detect different concentration ranges of the same gas.

[0005] The technical solution adopted by the utility model to solve its technical problems is: constructing a gas sensor, which includes a main structure, a range adjustment dial, and a gas sensitive component. The main structure has a cavity inside, and the gas sensitive component is arranged in the cavity. The main structure is also provided with a main air inlet, and the cavity is connected with the outside via the main air inlet. The range adjustment dial is penetrated by a plurality of air limiting holes with different apertures corresponding to a plurality of ranges, and the range adjustment dial is arranged above the main structure. After the range adjustment dial is moved to the point where the air limiting hole of the required range is located directly above the main air inlet, it is detachably mounted and fixed to the main structure.

[0006] Furthermore, in the gas sensor described in the utility model, the range adjustment disk is in the shape of a disk, the main air inlet and the air limiting holes are both arranged away from the center of the range adjustment disk, and a plurality of the air limiting holes are distributed in a ring shape around the center of the range adjustment disk, and the distance between the center of the air limiting hole and the center of the range adjustment disk is the same as the distance between the center of the main air inlet and the center of the range adjustment disk, and the aperture of the main air inlet is larger than the apertures of all the air limiting holes.

[0007] Furthermore, in the gas sensor described in the utility model, the main structure is cylindrical, a pointer is provided on the side wall of the range adjustment dial, and a plurality of scales corresponding to a plurality of ranges are arranged around the side wall of the main structure. When the pointer points to a scale corresponding to a certain range, the air limiting hole corresponding to the certain range is located directly above the main air inlet.

[0008] Furthermore, in the gas sensor described in the utility model, the main structure is cylindrical, a pointer is provided on the side wall of the main structure, and a plurality of scales are provided around the side wall of the range adjustment dial. When the pointer points to a scale corresponding to a certain range, the air limiting hole corresponding to the certain range is located directly above the main air inlet.

[0009] Furthermore, in the gas sensor described in the utility model, a waterproof and breathable film is pasted and covered on the top of the range adjustment disk to protect the air limiting hole.

[0010] Furthermore, in the gas sensor described in the utility model, the range adjustment disk is fixed to the top of the sensor main structure by fastening screws.

[0011] Furthermore, in the gas sensor described in the utility model, the fastening screw is installed at the center position of the range adjustment disk.

[0012] Furthermore, in the gas sensor described in the utility model, an O-ring groove is opened on the top of the main structure, the O-ring groove surrounds the main air inlet, an airtight O-ring is placed in the O-ring groove, and the bottom of the range adjustment disk presses the airtight O-ring placed in the O-ring groove to form an airtight seal.

[0013] Furthermore, in the gas sensor described in the utility model, a pin is installed at the bottom of the main structure, and the pin passes through the bottom of the main structure and extends into the cavity and is connected to the gas sensitive component in the cavity through a wire.

[0014] The gas sensor of the present utility model has the following beneficial effects: when the range needs to be adjusted, the range adjustment dial can be removed, the range adjustment dial can be turned to make the air limiting hole of the required range located directly above the main air inlet of the main structure, and then the range adjustment dial can be reinstalled. Therefore, the present utility model can realize adjustable detection range on a single gas sensor, so that without replacing the electrochemical sensor and the detection circuit, only simple operation is required to realize the application of a single sensor for gas detection of different levels of concentration, thereby reducing the application cost of the sensor in the field of gas concentration detection and facilitating the design and application of supporting circuits or detection equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work:

[0016] Figure 1 It is a schematic diagram of the structure of the gas sensor of the utility model;

[0017] Figure 2 It is a cross-sectional view of the gas sensor of the present utility model. DETAILED DESCRIPTION

[0018] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the relevant drawings below. Typical embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0019] refer to Figure 1-2 , Figure 1 It is a schematic diagram of the structure of the gas sensor of the utility model. Figure 2 The gas sensor of this embodiment specifically includes a main structure 1, a range adjustment disk 2, a gas sensitive component 5 and other components.

[0020] The main structure 1 is cylindrical. A cavity 10 is formed in the hollow interior thereof, and the gas-sensitive component 5 is arranged in the cavity 10. A main air inlet 8 is arranged at the upper part, i.e., the top, of the main structure 1, and the cavity 10 is connected to the outside via the main air inlet 8. The main air inlet 8 is arranged offset from the central axis of the main structure 1. A pin 12 is installed at the lower part, i.e., the bottom, of the main structure 1, and the pin 12 passes through the bottom of the main structure 1 and extends into the cavity 10 and is connected to the gas-sensitive component 5 in the cavity 10 through a wire 11. The electrical signal generated by the gas-sensitive component 5 is transmitted to the outside through the wire 11 and the pin 12 passing through the bottom of the cavity 10.

[0021] Wherein, the range adjustment disk 2 is in the shape of a disc, and the range adjustment disk 2 is provided with limited air holes 7 throughout its thickness direction, and the number of limited air holes 7 is multiple, and multiple refers to two or more than two. The specific number of limited air holes 7 is consistent with the required number of ranges, and each limited air hole 7 corresponds to a range, and the apertures of each limited air hole 7 are different. The larger the aperture, the smaller the range, and the smaller the aperture, the larger the range. The limited air holes 7 are all set away from the center of the range adjustment disk 2, and the multiple limited air holes 7 are evenly distributed in a ring shape around the center of the range adjustment disk 2. The limited air holes 7 with the smallest aperture are adjacent to the limited air holes 7 with the largest aperture, and the other limited air holes 7 are located between the limited air holes 7 with the smallest aperture and the limited air holes 7 with the largest aperture, and the apertures increase successively along the first direction. The so-called first direction refers to the circumferential direction of all the limited air holes 7.

[0022] The range adjustment disk 2 is arranged above the main structure 1, and the range adjustment disk 2 is fixed to the top of the sensor main structure 1 by means of a fastening screw 3. The fastening screw 3 is installed at the center of the range adjustment disk 2, and after passing through the center of the range adjustment disk 2, it continues to be screwed into the top center of the main structure 1. After the range adjustment disk 2 is moved to the point where the air-limiting hole 7 of the required range is located directly above the main air inlet 8, it is detachably fixed to the main structure 1 by means of the fastening screw 3.

[0023] Specifically, the distance between the center of the air limiting hole 7 and the center of the range adjustment disk 2 is the same as the distance between the center of the main air inlet 8 and the center of the range adjustment disk 2, and the aperture of the main air inlet 8 is larger than the apertures of all the air limiting holes 7. In this way, when the range adjustment disk 2 is rotated to switch different air limiting holes 7 directly above the main air inlet 8, it can ensure that the airflow of the air limiting holes 7 enters the main air inlet 8 smoothly without any obstruction.

[0024] Furthermore, in order to accurately position the required air-limiting hole 7 directly above the main air inlet 8 when the range adjustment disk 2 is turned, a pointer 14 is provided on the side wall of the range adjustment disk 2, and the pointer 14 points downward. A plurality of scales 15 corresponding to a plurality of ranges are arranged around the side wall of the main structure 1. When the pointer 14 points to a scale 15 corresponding to a certain range, the air-limiting hole 7 corresponding to the certain range is located directly above the main air inlet 8. In other embodiments, the pointer 14 can also be set at the top of the range adjustment disk 2 near the edge, and the pointer 14 points in the centrifugal direction. The setting objects of the pointer 14 and the scale 15 can also be swapped, and the pointer 14 is set on the side wall of the main structure 1, pointing upward, and correspondingly, a plurality of scales 15 are arranged around the side wall of the range adjustment disk 2; a plurality of scales 15 can also be set at the top of the range adjustment disk 2 and distributed in a circle along its edge.

[0025] Furthermore, a waterproof and breathable membrane 6 is pasted and covered on the top of the range adjustment disk 2 to protect the air limiting hole 7 .

[0026] Furthermore, an O-ring groove 9 is opened on the top of the main structure 1, and the O-ring groove 9 surrounds the main air inlet 8. An airtight O-ring 4 is placed in the O-ring groove 9, and the bottom of the range adjustment disk 2 presses the airtight O-ring 4 placed in the O-ring groove 9 to form an airtight seal.

[0027] After assembly, the overall structure of this embodiment is roughly a cylindrical structure. It should be noted that, in fact, it can also be other shapes. The specific shape is actually not limited, as long as a specific air limiting hole 7 can be selected to be aligned with the main air inlet 8. For example, it can be a square, an equilateral triangle, a regular pentagon, etc. Correspondingly, a certain side or point of the regular polygon can be used instead of the pointer and scale to indicate which specific air limiting hole 7 is aligned with the main air inlet 8.

[0028] During detection, the required range is selected according to the concentration range of the target gas, specifically: loosen the fastening screw 3, turn the range adjustment dial 2, so that the air-limiting hole 7 of the required range is located directly above the main air inlet 8, tighten the fastening screw 3, so that the lower part of the range adjustment dial 2 presses the airtight O-ring 4 placed in the O-ring groove 9 to form an airtight seal, and the external gas to be measured can only enter the cavity 10 through the air-limiting hole 7 and the main air inlet 8, so that the gas-sensitive component 5 generates an electrical signal corresponding to the gas concentration. The external detection equipment collects the above electrical signal through the pin 12, and converts the electrical signal into gas concentration by selecting the calculation parameters matching the air-limiting hole 7, and transmits or displays the gas concentration value in a preset form.

[0029] The following is a detailed description using an alcohol sensor based on the electrochemical two-electrode principle as an example. In this example, the alcohol sensor is designed with three ranges, namely 0-10ppm, 0-100ppm and 0-500ppm. The main structure 1 and the range adjustment disk 2 are made of ABS, the fastening screws 3 are made of stainless steel, the waterproof and breathable membrane 6 is made of PET / EPtfe, the gas-sensitive component 5 is a two-electrode solid electrolyte symmetrical electrode group, and the airtight O-ring 4 is made of fluororubber. The outer wall of the sensor main structure 1 is marked with three negative scales 15 during injection molding. The three scales 15 are marked with three groups of numbers 10, 100, and 500 respectively, corresponding to the three ranges used by the alcohol sensor. The range adjustment disk 2 is marked with a positive pointer 14 during injection molding. There are three air limiting holes 7 on the upper part of the range adjustment disk 2, which are through holes of 0.1mm±0.02mm, 0.3±0.02mm, and 2±0.02mm, respectively corresponding to the ranges of 0-500ppm, 0-100ppm, and 0-10ppm, respectively. The upper part of the range adjustment disk 2 is covered with an annular waterproof breathable membrane 6 to protect the air limiting holes 7. The range adjustment disk 2 is fixed to the sensor main structure 1 by a large cap stainless steel M3*5*8 fastening screw 3. The sensor main structure 1 is designed with a main air inlet (8) with a diameter of 3±0.2mm, and a fluororubber airtight O-ring 4 with an inner diameter of 4 and a wire diameter of 1.5 is placed in the O-ring groove 9 around the main air inlet (8); the gas sensitive component 5 is placed in the cavity 10 in the sensor main structure 1, and the electrical signal generated by the gas sensitive component 5 is transmitted to the outside through the wire 11 and the pin 12 passing through the wall of the cavity 10.

[0030] In order to test and verify the performance of the alcohol sensor of the embodiment, a detection module circuit board is equipped. The detection module circuit board is equipped with a current signal acquisition circuit, an operational amplifier and an MCU. The electrical signal of the alcohol sensor of the embodiment can be converted into an AD signal for measurement, and the calibration parameters of the alcohol sensor can be written and stored, and the real-time signal of the alcohol sensor can be converted into a concentration signal for serial port output.

[0031] Solder the pins of the alcohol sensor to the detection module circuit board, loosen and tighten the fastening screw 3 and turn the range adjustment dial 2, align the pointer 14 with the three scales of the scale 15 in turn to correspond to the three detection ranges, and use alcohol gas with a concentration of 50% of the upper limit of the range and clean air for calibration in each range, and obtain the parameters of the range through calibration and store them in the detection module circuit board;

[0032] By loosening and tightening the fastening screw 3 and turning the range adjustment dial 2, the pointer 14 is aligned with the three scales of the scale 15 in turn to correspond to the three detection ranges, and the calibration parameters corresponding to the range are selected through the serial port command. The gas phase test is performed with a concentration of about 70% of the upper limit of each range, and Table 1 is obtained:

[0033] Table 1 Test data

[0034]

[0035] In this way, the embodiment of the utility model only requires simple operation and calculation parameter switching to realize the application of a single electrochemical sensor and gas detection of different levels of concentration, reduce the application cost of electrochemical gas sensors in the field of gas concentration detection, and facilitate the design and application of supporting circuits or detection equipment.

[0036] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only. "Connected" or "connected" not only includes directly connecting two entities, but also indirectly connecting through other entities that have a beneficial improvement effect.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0038] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all fall within the protection of the utility model.

Claims

1. A gas sensor, characterized in that: The invention comprises a main structure (1), a range adjustment disk (2), and a gas-sensitive component (5); the main structure (1) has a cavity (10) inside, the gas-sensitive component (5) is arranged in the cavity (10), the main structure (1) is also provided with a main air inlet (8), the cavity (10) is connected to the outside via the main air inlet (8), the range adjustment disk (2) is provided with a plurality of air-limiting holes (7) of different apertures corresponding to a plurality of ranges, the range adjustment disk (2) is arranged above the main structure (1), and the range adjustment disk (2) is detachably mounted and fixed to the main structure (1) after being moved to a position where the air-limiting hole (7) of a desired range is located directly above the main air inlet (8).

2. The gas sensor according to claim 1, characterized in that The main air inlet (8) and the air limiting holes (7) are both arranged away from the center of the range adjustment disk (2); a plurality of the air limiting holes (7) are distributed in a ring shape around the center of the range adjustment disk (2); the distance between the center of the air limiting holes (7) and the center of the range adjustment disk (2) is the same as the distance between the center of the main air inlet (8) and the center of the range adjustment disk (2); the aperture of the main air inlet (8) is larger than the apertures of all the air limiting holes (7).

3. The gas sensor according to claim 2, characterized in that: A pointer (14) is arranged on the side wall of the range adjustment disk (2), and a plurality of scales (15) corresponding to a plurality of ranges are arranged around the side wall of the main structure (1); when the pointer (14) points to a scale (15) corresponding to a certain range, the air limiting hole (7) corresponding to the certain range is located directly above the main air inlet (8).

4. The gas sensor according to claim 2, characterized in that: The main structure (1) is cylindrical, a pointer (14) is provided on the side wall of the main structure (1), a plurality of scales (15) are arranged around the side wall of the range adjustment disk (2), and when the pointer (14) points to a scale (15) corresponding to a certain range, the air limiting hole (7) corresponding to the certain range is located directly above the main air inlet (8).

5. The gas sensor according to claim 1, characterized in that: The top of the range adjustment disk (2) is covered with a waterproof breathable membrane (6) to protect the air limiting hole (7).

6. The gas sensor according to claim 5, characterized in that: The range adjustment disk (2) is fixed to the top of the sensor main structure (1) by means of a fastening screw (3).

7. The gas sensor according to claim 6, characterized in that: The fastening screw (3) is installed at the center position of the range adjustment disk (2).

8. The gas sensor according to claim 1, characterized in that An O-ring groove (9) is provided on the top of the main structure (1), the O-ring groove (9) surrounds the main air inlet (8), an airtight O-ring (4) is placed in the O-ring groove (9), and the bottom of the range adjustment disk (2) presses the airtight O-ring (4) placed in the O-ring groove (9) to form an airtight structure.

9. The gas sensor according to claim 1, characterized in that: A pin (12) is installed at the bottom of the main structure (1); the pin (12) passes through the bottom of the main structure (1) and extends into the cavity (10), and is connected to the gas-sensitive component (5) in the cavity (10) via a wire (11).

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