High-precision gas sensor for acetone detection

Abstract

A high-precision gas sensor for acetone detection comprises a sensing body and a base, a mounting groove allowing the sensing body to be embedded is formed in the base, and two conductive electrodes are arranged on the inner wall of the mounting groove; the sensing body comprises a detection electrode and a gas sensitive material, the detection electrode is distributed in a snake shape, and the two ends of the detection electrode are connected with the conductive electrodes on the corresponding sides respectively; the mounting groove is filled with the gas sensitive material and completely covers the detection electrode, gas inlet grooves are formed in the positions, located between the adjacent linear sections of the detection electrode, of the gas facing side of the gas sensitive material, a back side gas channel is formed in the back side of the gas sensitive material, the back side gas channel corresponds to the back of the detection electrode in an overlapped mode, and the back side gas channel communicates with the gas inlet grooves; a plurality of exhaust holes used for exhausting air are formed in the bottom of the base and communicate with the back side air channel. According to the utility model, the sensitivity and the detection precision of the signal change can be further improved by increasing the effective reaction contact area of the gas to be detected and the gas sensitive material.

Description

Technical Field

[0001] The utility model relates to the technical field of gas sensors, and specifically relates to a high-precision gas sensor for acetone detection. Background Art

[0002] Respiratory tests have been recorded in the history of medicine. Through a large number of studies, doctors have found that certain components in the exhaled gas of people are related to some diseases, and even the physiological and pathological processes of the body can be insight through the concentration changes of these exhaled gases. Analyzing exhaled gas has been proposed as another complementary method to blood tests and urine monitoring, and respiratory monitoring is safer and more convenient. Acetone is one of the most abundant volatile organic compounds in human breath, and acetone is related to the metabolism and lipolysis of glucose in the human body. Through medical test analysis, the acetone content in exhaled gas is positively correlated with the acetone content in the human body. Based on this mechanism, acetone can be used as an important gas marker for monitoring diabetes.

[0003] Existing gas sensors are basically connected to an external circuit through their external electrodes and wires. This connection method requires conductive lines to be set on the sensor and then connected to the external circuit, and the manufacturing process is relatively cumbersome, resulting in increased costs. Based on this, a new type of gas sensor has emerged in the prior art.

[0004] The applicant's prior patent application CN202322230042.1 discloses an acetone sensor and a detector for the acetone content in the exhaled gas of diabetic patients. An acetone sensor includes a sensing part equipped with a detection electrode and a gas-sensitive material; and a base for carrying the sensing part. The sensing part includes a substrate, a groove is provided on the upper end surface of the substrate, the detection electrode is placed in the groove, and the gas-sensitive material is filled in the groove and completely covers the detection electrode. The detection electrode is distributed in a serpentine shape, and its two ends extend out from the side wall of the substrate. A "V" groove is provided on the side wall of the straight part of the detection electrode, and the "V" groove is arranged along the thickness direction of the detection electrode. The base includes a base body, an installation groove for embedding the sensing part is provided on the base body, and two conductive electrodes capable of being respectively connected to the two ends of the detection electrode are provided on the inner wall of the installation groove.

[0005] Although the electrodes in the above-mentioned existing acetone sensors are distributed in a serpentine shape and provided with "V" grooves, the area of the gas-sensitive material and the corresponding detection electrode that can contact the gas is still limited within the unit cross-sectional area, resulting in relatively low sensitivity of signal change and poor detection accuracy in the miniaturization of acetone sensors. Summary of the Utility Model

[0006] The utility model aims to provide a high-precision gas sensor for acetone detection, which can further improve the sensitivity of signal change and detection accuracy.

[0007] To solve the above technical problems, the specific solution adopted by the present utility model is a high-precision gas sensor for acetone detection, which includes a sensing body and a base. An installation groove for embedding the sensing body is provided on the base, and two conductive electrodes are arranged on the inner wall of the installation groove; the sensing body includes a detection electrode and a gas-sensitive material. The detection electrode is distributed in a serpentine shape, and its two ends are respectively connected to the conductive electrodes on the corresponding side; the gas-sensitive material is filled in the installation groove and completely covers the detection electrode.

[0008] Air inlet grooves are provided between adjacent straight segments of the detection electrode on the air-facing side of the gas-sensitive material. A back-side air passage is provided on the back side of the gas-sensitive material. The back-side air passage coincides with the back of the detection electrode. The back-side air passage is communicated with a plurality of air inlet grooves. A plurality of exhaust holes for discharging gas are provided at the bottom of the base, and the exhaust holes are communicated with the back-side air passage.

[0009] As another optimized solution of the above high-precision gas sensor for acetone detection: V-shaped grooves are provided on the side walls of the straight segments of the detection electrode, and the V-shaped grooves are arranged along the thickness direction of the detection electrode.

[0010] As another optimized solution of the above high-precision gas sensor for acetone detection: the width of the air inlet groove is smaller than the width of the back-side air passage.

[0011] As another optimized solution of the above high-precision gas sensor for acetone detection: the shape of the side wall of the gas-sensitive material communicating with the air inlet groove is wavy.

[0012] As another optimized solution of the above high-precision gas sensor for acetone detection: the air-facing side of the gas-sensitive material is wavy.

[0013] As another optimized solution of the above high-precision gas sensor for acetone detection: the gas-sensitive material is tin dioxide nanomaterial or tungsten trioxide nanomaterial.

[0014] As another optimized solution of the above high-precision gas sensor for acetone detection: the materials of the detection electrode and the conductive electrode are metal Au, Cu or Ag.

[0015] As another optimized solution of the above high-precision gas sensor for acetone detection: the conductive electrode is connected with an elastic pressing piece. When the sensing body is placed into the installation groove of the base, the conductive electrode is electrically connected to the detection electrode through the elastic pressing piece.

[0016] Compared with the prior art, the present utility model has the following beneficial effects:

[0017] 1. In the present utility model, a back air duct is provided on the back side of the gas-sensitive material. The back air duct is connected to an air inlet groove opened on the air-facing side of the sensor, and the back air duct correspondingly covers most of the back of the detection electrode, so that the gas to be measured can reach the detection electrode and the position of the gas-sensitive material on the back side of the sensor through the air inlet groove and the back air duct. Moreover, when the gas to be measured passes through the air inlet groove, it can also contact the gas-sensitive materials on both sides thereof. Thus, the gas-sensitive materials on the front and back sides and the left and right sides of the detection electrode can all contact the gas to be measured and cooperate with the detection electrode to measure the acetone content. Compared with the prior patent mentioned in the background art, the effective reaction contact area between the gas-sensitive material and the detection electrode is greatly increased, further improving the sensitivity to signal changes and the detection accuracy.

[0018] 2. In the preferred embodiment of the present utility model, the width of the air inlet groove is smaller than the width of the back air duct, so that the flow rate of the gas to be measured decreases after entering the back air duct through the air inlet groove, facilitating more sufficient reaction between the gas to be measured and the gas-sensitive material at the position in the back air duct and ensuring the detection accuracy.

[0019] 3. In the preferred embodiment of the present utility model, the air-facing side of the gas-sensitive material is a wavy structure, or the side wall of the back air duct communicating with the air inlet groove and the gas-sensitive material is a wavy structure, both of which can increase the contact area between the gas-sensitive material and the gas to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the main structure of the present utility model;

[0021] Figure 2 is Figure 1 the sectional structure schematic diagram taken along the A-A direction of

[0022] Figure 3 is the structure schematic diagram of Embodiment 2.

[0023] Reference numerals: 1, base; 101, installation groove; 102, exhaust hole; 2, detection electrode; 201, V-shaped groove; 3, gas-sensitive material; 301, air inlet groove; 302, back air duct; 4, conductive electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following further elaborates on the technical solutions of the present utility model in combination with specific embodiments. For parts not described in detail in the following embodiments of the present utility model, such as the conductive electrodes at both ends of the detection electrode being electrically connected to the detection electrode through elastic pressing sheets, etc., should all be immediately understood as the prior art known or should be known to those skilled in the art.

[0025] Embodiment 1

[0026] A high-precision gas sensor for acetone detection, such as Figure 1 and Figure 2As shown in the figure, it includes a sensor body and a base 1 for carrying and installing the sensor body. The base 1 is rectangular, and an installation groove 101 is provided on the upper side of the base 1. Conductive electrodes 4 are respectively arranged on the left and right inner side walls of the installation groove 101, and the conductive electrodes 4 are respectively connected with elastic pressing sheets (not shown in the figure).

[0027] The sensing body is embedded in the installation groove 101. The sensing body includes a detection electrode 2 and a gas-sensitive material 3. The detection electrode 2 is distributed in a serpentine shape in the installation groove 101, and the two adjacent straight-line segments of the detection electrode 2 distributed in a serpentine shape are both arc-shaped segments. When the sensing body is placed in the installation groove 101, the left and right ends of its detection electrode 2 are respectively connected with the corresponding side conductive electrodes 4 through elastic pressing sheets. The function of the elastic pressing sheets is to improve the connection effect between the conductive electrode 4 and the detection electrode 2. The materials of the detection electrode 2 and the conductive electrode 4 are metal Au, Cu or Ag. Of course, other materials with good electrical conductivity can also be selected.

[0028] The gas-sensitive material 3 is filled in the installation groove 101 and completely covers the detection electrode 2. The gas-sensitive material 3 is a tin dioxide nanomaterial or a tungsten trioxide nanomaterial. When the gas-sensitive material 3 contacts the gas to be detected, oxygen molecules are adsorbed on the surface of the gas-sensitive material 3 fibers. The gas-sensitive material 3 captures electrons, and then chemically adsorbed oxygen species are formed. In this process, an electron depletion layer will be generated on the material surface, resulting in an increase in resistance. When the nanofibers are exposed to acetone, the ionized oxygen species will react with acetone molecules and release electrons back to the conductive band. These released electrons increase the electron concentration, resulting in a decrease in resistance.

[0029] Air inlet grooves 301 are provided between the adjacent straight-line segments of the detection electrode 2 on the gas-sensitive material 3. The air inlet of the air inlet groove 301 is on the side wall of the windward side of the upper end surface of the gas-sensitive material 3, and its air outlet is inside the gas-sensitive material 3. A backside air duct 302 is provided on the back side of the gas-sensitive material 3 opposite to its windward side. The backside air duct 302 correspondingly covers most of the back of the detection electrode 2. The backside air duct 302 is communicated with a plurality of air inlet grooves 301. A plurality of exhaust holes 102 for discharging gas are provided at the bottom of the base 1. The two exhaust holes 102 are respectively communicated with the air outlets at both ends of the backside air duct 302.

[0030] During use, the gas to be detected can reach the positions of the detection electrode 2 and the gas-sensitive material 3 on the back side of the sensor through the air inlet grooves 301 and the backside air duct 302. And when the gas to be detected passes through the air inlet grooves 301, it can also contact the gas-sensitive material 3 on both sides of it. Thus, the gas-sensitive material 3 on the front and back sides and the left and right sides of the detection electrode 2 can all contact the gas to be detected and cooperate with the detection electrode 2 to measure the acetone content. Compared with the prior patent, the effective reaction contact area between the gas-sensitive material 3 and the detection electrode 2 is greatly increased, further improving the sensitivity to signal changes and further improving the detection accuracy.

[0031] In this embodiment, the width of the intake groove 301 is smaller than the width of the dorsal airway 302, so that the flow rate of the gas to be measured decreases after entering the dorsal airway 302 through the intake groove 301, facilitating the more sufficient reaction between the gas to be measured and the gas-sensitive material 3 at the position in the dorsal airway 302 and ensuring the detection accuracy.

[0032] A V-shaped groove 201 is provided on the side wall of the straight segment of the detection electrode 2, and the V-shaped groove 201 is arranged along the thickness direction of the detection electrode 2. The detection electrode can detect the signal change of the gas-sensitive material 3 layer. Due to the existence of the V-shaped groove 201, the contact area between the gas-sensitive material 3 and the detection electrode 2 can be increased, which helps to improve the sensitivity of the detection electrode 2 to signal changes.

[0033] The base 1 is made of non-metallic materials such as glass and ceramics, and the curves at the four corners of the base 1 are all arc-shaped, which can improve the aesthetics of the overall sensor appearance and facilitate the staff to hold and use the sensor.

[0034] The above is the basic implementation mode of the present utility model, and further improvements, optimizations and limitations can be made on this basis to obtain the following embodiments:

[0035] Embodiment 2

[0036] This embodiment is an improved scheme based on Embodiment 1, and its main structure is the same as that of Embodiment 1. The improvement lies in: as Figure 3 shown, the upper end face of the gas-sensitive material 3 bulges out and is installed in the groove 101 on the air-facing side, and the shape of the side wall on the air-facing side of its upper end face is wavy. The wavy design can increase the contact area between the gas-sensitive material 3 and the gas to be measured, thereby improving the sensitivity of the detection electrode 2 to signal changes and further improving the detection accuracy.

[0037] Embodiment 3

[0038] This embodiment is another improved scheme based on Embodiment 1, and its main structure is the same as that of Embodiment 1. The improvement lies in: the shape of the side wall of the gas-sensitive material 3 on the side communicating with the intake groove 301 is wavy. The wavy setting can increase the contact area between the gas to be measured flowing in the dorsal airway 302 and the gas-sensitive material 3, thereby improving the sensitivity of the detection electrode 2 to signal changes and further improving the detection accuracy.

Claims

1. A high-precision gas sensor for acetone detection, comprising a sensor body and a base (1), wherein the base (1) is provided with a mounting groove (101) for the sensor body to be embedded, and two conductive electrodes (4) are arranged on the inner wall of the mounting groove (101); the sensor body comprises a detection electrode (2) and a gas-sensitive material (3), the detection electrode (2) is distributed in a serpentine shape, and its two ends are respectively connected to the conductive electrodes (4) on the corresponding side; the gas-sensitive material (3) is filled in the mounting groove (101) and completely covers the detection electrode (2), characterized in that: An air inlet groove (301) is provided on the air-facing side of the air-sensitive material (3) between adjacent straight line segments of the detection electrode (2); a dorsal air channel (302) is provided on the back side of the air-sensitive material (3); the dorsal air channel (302) coincides with the back of the detection electrode (2); the dorsal air channel (302) is connected to the plurality of air inlet grooves (301); and a plurality of exhaust holes (102) for exhausting gas are provided at the bottom of the base (1); the exhaust holes (102) are connected to the dorsal air channel (302).

2. A high-precision gas sensor for acetone detection according to claim 1, characterized in that: A V-shaped groove (201) is provided on the side wall of the straight section of the detection electrode (2), and the V-shaped groove (201) is provided along the thickness direction of the detection electrode (2).

3. A high-precision gas sensor for acetone detection according to claim 1, characterized in that: The width of the air inlet groove (301) is smaller than the width of the dorsal air passage (302).

4. A high-precision gas sensor for acetone detection according to claim 1, characterized in that: The shape of a side wall connecting the gas-sensitive material (3) and the air inlet groove (301) is wavy.

5. The high-precision gas sensor for acetone detection according to claim 1, characterized in that: The air-facing side of the air-sensitive material (3) is wavy.

6. A high-precision gas sensor for acetone detection according to claim 1, characterized in that: The gas-sensitive material (3) is a tin dioxide nanomaterial or a tungsten trioxide nanomaterial.

7. A high-precision gas sensor for acetone detection according to claim 1, characterized in that: The detection electrode (2) and the conductive electrode (4) are made of metal Au, Cu or Ag.

8. The high-precision gas sensor for acetone detection according to claim 1, characterized in that: The conductive electrode (4) is connected to an elastic pressing sheet, and when the sensor body is placed in the mounting groove (101) of the base (1), the conductive electrode (4) is electrically connected to the detection electrode (2) via the elastic pressing sheet.

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