Multi-channel dynamic gas sensor detection device and use method thereof

Abstract

The invention discloses a multi-channel dynamic gas sensor detection device, which comprises a plurality of cavities used for accommodating a plurality of gas sensors to be tested; the plurality of programmable power supplies are electrically connected with the gas sensors in the plurality of cavities and are used for inputting heating voltage and testing voltage to the gas sensors; the analog-to-digital conversion device is in communication connection with the plurality of gas sensors; the upper computer is in communication connection with the analog-to-digital conversion device; and the gas shunting device is arranged in the cavity and is communicated with an external gas source. According to the multi-channel dynamic gas sensor detection device disclosed by the invention, through the arrangement of the gas shunting device, the test of batch gas sensors can be effectively realized.

Description

Technical Field

[0001] The invention relates to a gas sensor detection device, and more particularly to a multi-channel dynamic gas sensor detection device. Background Art

[0002] Gas sensors need to be tested during the factory process to ensure that the working performance of the gas sensors shipped out of the factory is qualified and stable. Therefore, there is a publication number N118817779 in the prior art, which is named a dynamic and static integrated gas sensor array gas-sensitive performance test device. The device is implemented on the same device to perform dynamic gas-sensitive tests and static gas-sensitive tests on the gas sensor array, realizing the integrated design of the two systems, separating the response and recovery processes of the static test, and facilitating the provision of test conditions such as different humidity background gases and ultraviolet light source irradiation. There is also a publication number N220438281 in the prior art, which is named a gas-sensitive characteristic test device for a gas sensor, which discloses that the gas sensor is placed in a uniform gas environment by setting a wind guide cone to increase the test accuracy. However, the above two methods have the following disadvantages:

[0003] 1. The effect of the gas flow rate on the sensor is not controlled in the small cavity.

[0004] 2. The sensor data is not monitored and recorded in real time in the device.

[0005] 3. The test sensor types are single and the measurement range is not mentioned.

[0006] 4. The number of measuring sensors is small. Summary of the invention

[0007] In view of the deficiencies in the prior art, an object of the present invention is to provide a multi-channel dynamic gas sensor detection device and a method of using the same which can effectively avoid one or more of the above-mentioned disadvantages.

[0008] To achieve the above object, the present invention provides the following technical solution: a multi-channel dynamic gas sensor detection device, characterized in that it includes:

[0009] A plurality of cavities, the cavities being used to accommodate a plurality of gas sensors to be tested;

[0010] A plurality of programmable power supplies, wherein the plurality of programmable power supplies are electrically connected to the gas sensors in the plurality of cavities and are used to input heating voltage and test voltage to the gas sensors;

[0011] An analog-to-digital conversion device, which is in communication connection with a plurality of gas sensors and is used to receive analog signals output by the gas sensors and convert them into digital signals for output;

[0012] A host computer, which is in communication connection with the analog-to-digital conversion device, and is used to receive the digital signal output by the analog-to-digital conversion device, and analyze and process the digital signal to complete the test of the gas sensor;

[0013] A gas diversion device is connected to an external gas source to divert the test gas and send it into the cavity. Several of the cavities are connected to a gas flow meter one by one to detect the gas flow flowing into the cavity through the gas flow meter.

[0014] As a further improvement of the present invention, the cavity is composed of an upper cover and a bottom box, the upper cover is provided with an air inlet and an air outlet, the upper cover is provided with an air path structure, the air path structure is connected to the air inlet and the air outlet, a signal processing circuit board is provided in the bottom box, several gas sensors to be tested are installed side by side on the signal processing circuit board, and when the upper cover is covered on the bottom box, the air outlet holes of the air path structure correspond one by one to the gas sensors, the side wall of the bottom box is provided with an input and output aviation plug, the input and output aviation plug is communicatively connected to the analog-to-digital conversion device through a signal line, the signal processing circuit board is connected to the input and output aviation plug, so that the output signal is input into the analog-to-digital conversion device after passing through the input and output aviation plug.

[0015] As a further improvement of the present invention, a plurality of circuit board mounting screw seats in the shape of inverted trumpets are further provided in the base box, and the signal processing circuit board is mounted on the circuit board mounting screw seats by means of bolts.

[0016] As a further improvement of the present invention, a top cover bayonet arm is fixed on the side position of the upper side of the upper cover, and the air inlet and the air outlet are both provided with vent hole pagoda heads, and are connected to the air path structure by means of a pipe connected to the vent hole pagoda head.

[0017] As a further improvement of the present invention, the signal processing circuit board comprises:

[0018] A signal conversion circuit board is provided with a plurality of circuit board positioning holes, and the signal conversion circuit board is fixed by bolts passing through the circuit board positioning holes and threadedly connected with the mounting screw seat;

[0019] A plurality of sensor fixtures, wherein the plurality of sensor fixtures are mounted side by side on a signal conversion circuit board, and are used to mount the gas sensors to be tested side by side;

[0020] A load board socket, fixedly mounted on the signal conversion circuit board, is used to mount the load board;

[0021] The power input socket is fixedly installed on the signal conversion circuit board and is used to plug in the power cord;

[0022] The signal output socket is fixedly installed on the signal conversion circuit board and is used to plug in the signal line.

[0023] As a further improvement of the present invention, the sensor fixture includes a connecting circuit board, a base and a top pressure cover. The connecting circuit board is fixedly installed on the lower side of the base to be electrically connected to the gas sensor installed between the base and the top pressure cover. A MEMS sensor limiting groove is provided in the base. One end of the top pressure cover is hingedly installed on the side of the base to flip the MEMS sensor limiting groove upward to open or flip the MEMS sensor limiting groove downward to close the MEMS sensor limiting groove. A top air vent is provided on the top pressure cover, and the top air vent is used to connect with the air outlet hole of the air path structure when the upper cover is covered on the bottom box.

[0024] As a further improvement of the present invention, a plurality of cross pins are plugged into the lower side of the connecting circuit board, and claw spring sockets are coaxially fixed to the lower ends of the plurality of cross pins. The claw spring sockets are plugged into and installed on the signal conversion circuit board to fix the connecting circuit board to the signal conversion circuit board and electrically connect it to the signal conversion circuit board.

[0025] As a further improvement of the present invention, a top pressure cover spring is installed on the hinge shaft at one end of the top pressure cover which is hinged to the base to provide elastic force to drive the top pressure cover to flip down. A buckle is hinged at one end of the top pressure cover facing away from the top pressure cover spring. A lever is formed at one end of the buckle, and a buckle clip is formed at the other end. The buckle clip is a bar structure. A buckle groove is provided on the side wall of the base. When the top pressure cover flips down, the buckle flips downward, and the buckle clip hooks the buckle groove. A buckle compression spring is provided at the hinge between the buckle and the top pressure cover to provide elastic force to drive the buckle to flip downward.

[0026] As a further improvement of the present invention, the air path structure includes an air path pipeline, an air inlet and an air outlet opened at both ends of the air path pipeline, and a plurality of air vents opened on the side wall of the air path pipeline, the air vents serve as air outlets of the air path structure, and an air path channel running through both ends of the air path pipeline is opened in the air path pipeline, the air inlet and the air outlet are connected with the air inlet and the air outlet through pipelines respectively, and a plurality of the air vents are evenly arranged on the side wall of the air path pipeline along the length direction of the air path pipeline, a supporting structure is fixed on the side of the air path pipeline facing away from the air vents, a positioning seat is fixed on the supporting structure, a movable screw hole is opened on the positioning seat, and the supporting structure with the air path pipeline is installed on the upper cover in a manner that a bolt with a spring passes through the movable screw hole and is threadedly connected to the upper cover.

[0027] Another aspect of the present invention provides a method for using the above device, comprising the following steps:

[0028] Step 1: Take a sensor fixture, flip up and open the top cover, place the MEMS sensor to be tested in the MEMS sensor limit slot, and ensure that the heating pole of the MEMS sensor corresponds to the heating pole on the connection circuit board;

[0029] Step 2: Flip the top cover downward and buckle it with the buckle, then plug and install the claw spring socket on the signal conversion circuit board to complete the installation of the MEMS sensor;

[0030] Step 3: According to the response resistance of the MEMS sensor to be tested, select a load board with a similar response resistance and insert it into the load board socket, then cover the cavity cover so that the vent holes on the gas path structure are tightly pressed with the top pressure cover, so that the top vent holes are connected with the vent holes;

[0031] Step 4: Connect the cavity to the programmable power supply and analog-to-digital conversion device through the input and output aviation plugs, and adjust the flow control valve until the flow of the gas flow meter meets the test requirements. Then insert the air pipe into the air inlet and connect the air pipe at the air outlet to the gas recovery device.

[0032] Step 5: Set the heating voltage and test voltage of the programmable power supply on the host computer, and obtain the test resistance of the sensor at the same time, then introduce the test gas, and test the sensor by directly observing the response state of the sensor through the host computer based on the principle that the sensor responds to the test gas;

[0033] Step 6: After the test is completed, stop ventilation, set the program-controlled power supply to cut off, open the cavity cover and take out the gas sensor.

[0034] The beneficial effects of the present invention include realizing a large number of sensor tests, convenient sensor testing, easy placement and placement, controllable MEMS sensor heating current and test voltage, suitable for testing different MEMS gas sensors, stable test results, and accurate identification of sensor recovery time and response time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a module block diagram of the multi-channel dynamic gas sensor detection device of the present invention;

[0036] Figure 2 It is the module block diagram of the cavity;

[0037] Figure 3 is a schematic diagram of the structure of the cavity;

[0038] Figure 4 It is a structural schematic diagram of a signal processing circuit board;

[0039] Figure 5 It is a structural schematic diagram of the gas path structure;

[0040] Figure 6 It is a structural schematic diagram of the sensor fixture;

[0041] Figure 7 is a schematic diagram of a MEMS sensor to be tested;

[0042] Figure 8 It is the MEMS sensor heating voltage-micro hot plate temperature characteristic curve;

[0043] Fig. 9 It is a schematic diagram of response data of the multi-channel dynamic gas sensor detection device of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below in detail with reference to the embodiments shown in the accompanying drawings.

[0045] Reference Figures 1 to 9 As shown, a multi-channel dynamic gas sensor detection device of this embodiment is characterized by comprising:

[0046] A plurality of cavities, the cavities being used to accommodate a plurality of gas sensors to be tested;

[0047] A plurality of programmable power supplies, wherein the plurality of programmable power supplies are electrically connected to the gas sensors in the plurality of cavities and are used to input heating voltage and test voltage to the gas sensors;

[0048] An analog-to-digital conversion device, which is in communication connection with a plurality of gas sensors and is used to receive analog signals output by the gas sensors and convert them into digital signals for output;

[0049] A host computer, which is in communication connection with the analog-to-digital conversion device, and is used to receive the digital signal output by the analog-to-digital conversion device, and analyze and process the digital signal to complete the test of the gas sensor;

[0050] A gas diversion device is connected to an external gas source to divert the test gas and send it into the cavity. Several of the cavities are connected to a gas flow meter one by one to detect the gas flow rate flowing into the cavity through the gas flow meter. This embodiment provides an implementation plan for four cavities, as shown in detail. Figure 1As shown, it includes 4 cavities, 4 programmable power supplies, 1 analog-to-digital conversion device, 4 gas flow meters and a host computer. A single cavity can accommodate up to 8 sensors, and up to 4 are equipped in parallel. The tested MEMS sensor usually works in a heated state. The heating voltage and the test voltage can be adjusted by the programmable power supply controlled by the host computer. During the measurement process, the voltage on it is tested by a voltage divider resistor, and then the voltage value of the test resistor is calculated. These voltage signals are then transmitted to the host computer through the analog-to-digital conversion device, and further processed by the host computer to obtain the value of the measured resistor. In this embodiment, in view of the influence of the air flow velocity on the sensor performance, the device introduces an air flow diversion device. First, the gas diverter is used to evenly divide the air flow into 4 paths, and the gas flow of each path is accurately controlled by observing the flow meter. After passing through the cavity, the gas will be uniformly recycled and processed, so that multiple gas sensors can be effectively tested together.

[0051] This embodiment provides the following internal structure of the cavity: Figure 2 and Figure 3 As shown, the cavity is composed of an upper cover and a bottom box, the upper cover is provided with an air inlet 32 ​​and an air outlet 34, the upper cover is provided with an air path structure 33, the air path structure 33 is connected with the air inlet 32 ​​and the air outlet 34, a signal processing circuit board is provided in the bottom box, a plurality of gas sensors to be tested are installed side by side on the signal processing circuit board, and when the upper cover is covered on the bottom box, the air outlet holes of the air path structure 33 correspond to the gas sensors one by one, an input and output aviation plug 38 is provided on the side wall of the bottom box, the input and output aviation plug 38 is connected to the analog-to-digital conversion device through a signal line, and the signal processing circuit board is connected to the input and output aviation plug 38 to output a signal After passing through the input and output aviation plug 38, it is input into the analog-to-digital conversion device. A number of inverted trumpet-shaped circuit board mounting screw seats 36 are also provided in the bottom box. The signal processing circuit board is mounted on the circuit board mounting screw seats 36 by bolts. A top cover bayonet arm 31 is fixed to the side position of the upper side of the upper cover. The top cover bayonet arm 31 is used to install the existing lock to achieve that the air inlet 32 ​​and the air outlet 34 between the upper cover and the bottom box are both provided with a vent hole pagoda head 35, and are connected to the air path structure 33 by means of a pipe sleeve connected to the vent hole pagoda head 35. In this embodiment, the signal processing circuit board tests the voltage thereon through a voltage divider resistor, and then calculates the voltage value of the test resistor. To ensure the safety of the MEMS sensor, a self-resetting fuse is connected in series in the heating circuit to prevent damage to the sensor caused by excessive heating current. In addition, the cavity in this embodiment is equipped with a temperature and humidity sensor for real-time monitoring of the temperature and humidity conditions in the cavity, providing the necessary environmental parameter basis for the measurement results. The gas path structure 33 is mainly composed of input gas and output gas channels, and an air outlet is opened in the gas path. The sensor can detect gas at the air outlet position.

[0052] In this embodiment, the following signal processing circuit board is provided: Figure 4 As shown, including:

[0053] A signal conversion circuit board 30, on which a plurality of circuit board positioning holes 27 are formed, and the signal conversion circuit board 30 is fixed by bolts passing through the circuit board positioning holes 27 and threadedly connected with the mounting screw seat 36;

[0054] A plurality of sensor fixtures 25, wherein the plurality of sensor fixtures 25 are mounted side by side on a signal conversion circuit board 30, and are used to mount the gas sensors to be tested side by side;

[0055] A load board socket 26, fixedly mounted on the signal conversion circuit board 30, for mounting the load board;

[0056] A power input socket 28 is fixedly mounted on the signal conversion circuit board 30 and is used to plug in a power cord;

[0057] The signal output socket 29 is fixedly mounted on the signal conversion circuit board 30 and is used to plug in the signal line. In the above embodiment, the design of the sensor fixture 25 is intended to facilitate the pick-up and placement of the sensor and ensure that the sensor is measured within a closed test area. In addition, the sensor fixture 25 is pluggable and installed on the circuit board, which is convenient for daily maintenance and operation. The pluggable load board 26 is equipped with 8 resistors, which correspond to the load resistance of each measurement circuit. This pluggable design makes the replacement of the load resistance more convenient and can meet the needs of different measurement resistances, thereby further improving the accuracy of the test.

[0058] This embodiment further provides a specific structure of the sensor fixture 25. Figure 6As shown, it includes a connecting circuit board 9, a base 10 and a top pressure cover 4. The connecting circuit board 9 is fixedly installed on the lower side of the base 10 to be electrically connected to the gas sensor installed between the base 10 and the top pressure cover 4. A MEMS sensor limiting groove 13 is provided in the base 10. One end of the top pressure cover 4 is hingedly installed on the side of the base 10 to flip upward to open the MEMS sensor limiting groove 13 or flip downward to close the MEMS sensor limiting groove 13. A top vent 3 is provided on the top pressure cover 4. The top vent 3 is used to communicate with the air outlet of the air path structure 33 when the upper cover is covered on the bottom box. A plurality of cross pins 7 are plugged into the lower side of the connecting circuit board 9. The lower ends of the plurality of cross pins 7 are coaxially fixed with claw spring sockets 8. The claw spring sockets 8 are plugged and installed on the signal conversion circuit The circuit board 30 is used to fix the connecting circuit board 9 to the signal conversion circuit board 30 and electrically connect it to the signal conversion circuit board 30. A top pressure cover spring 5 is installed on the hinge shaft at one end of the top pressure cover 4 and the base 10 to provide an elastic force to drive the top pressure cover 4 to flip down. The top pressure cover 4 is hinged with a buckle 1 at one end facing away from the top pressure cover spring 5. A lever is formed at one end of the buckle 1 and a buckle clip 12 is formed at the other end. The buckle clip 12 is a barb structure. A buckle groove is provided on the side wall of the base 10. When the top pressure cover 4 flips down, the buckle 1 flips downward and the buckle clip 12 hooks the buckle groove. A buckle compression spring 14 is provided at the hinge between the buckle 1 and the top pressure cover 4 to provide an elastic force to drive the buckle 1 to flip downward. The buckle 1 and the top pressure cover 4 are fastened together by screws and nuts, and are supplemented by a compression spring to ensure the stability of the connection. Under the action of the compression spring, the buckle buckle 12 of the buckle 1 fits tightly with the base 10, effectively preventing the gap between the top pressure cover 4 and the base 10. The top pressure cover 4 and the base 10 are also fixed with screws and nuts, and the compression spring keeps the tight compression state. This design enables the sensor to achieve good contact with the ejector pin, while reducing the gap between the sensor and the top pressure cover 4, effectively preventing gas leakage. A vent 3 is provided in the center of the top pressure cover 4. The size of the vent 3 matches the outlet of the gas path structure 33, ensuring that the sensor can smoothly exchange gas with the external environment. In addition, the side of the vent 3 facing the sensor is designed as an annular protrusion, which can fit tightly with the sensor, further enhancing the sealing performance of the fixture. The base 10 is cleverly provided with a limit groove 13 around the sensor. This design effectively avoids the problem that the sensor fails to accurately align with the ejector pin when placed. The fixture is embedded with 4 spring ejectors, which respectively support the heating positive and negative electrodes of the sensor and the two ends of the response resistor. At the same time, a through hole is opened at the corresponding position of the buckle buckle 12 so that the spring ejector pin can pass smoothly and contact the sensor, and the four cross round pins are welded on the connecting circuit board 9 to conduct electrical signals. The signals are respectively connected to the four signals of the ejector pin.The pressing buckle 12 is fixed to the connecting circuit board 9 by welding a T-shaped round pin, and the cross round pin is inserted into the claw spring socket, thereby fixing the structure of the entire fixture. The claw spring socket is welded on the signal conversion circuit board, making the plug-in and pull-out operation of the fixture simple and quick, and facilitating the replacement and maintenance of the sensor.

[0059] In this embodiment, the following gas path structure 33 is provided: Figure 5 As shown, it includes an air pipeline 19, an air inlet 15 and an air outlet 21 opened at both ends of the air pipeline 15, and a plurality of vents 18 opened on the side wall of the air pipeline 15. The vents 18 serve as air outlets of the air path structure 33. An air path channel 23 running through both ends of the air pipeline 19 is opened in the air pipeline 19. The air inlet 15 and the air outlet 21 are connected to the air inlet 32 ​​and the air outlet 34 through pipelines, respectively. The plurality of vents 18 are evenly arranged along the length direction of the air pipeline 19. On the side wall of the gas pipeline 19, a support structure 22 is fixed on the side of the gas pipeline 19 facing away from the vent 18, and a positioning seat 17 is fixed on the support structure 22. A movable screw hole 24 is provided on the positioning seat 17. The support structure 22 is installed on the upper cover with the gas pipeline 19 by passing a bolt through the movable screw hole 24 and threading it with the upper cover. The two ports of the air inlet 15 and the exhaust port 21 can be better connected to each other, and the air inlet 15 is connected to the gas source through a pagoda connector and a hose. When the gas enters the gas path through the air inlet 15, it will flow out from the exhaust port 21 and diffuse to the sensor through the vent 18, and the vent 18 at this time is the above-mentioned outlet. In order to ensure that the gas does not leak out, a sealing ring is provided in the gas path structure, that is, a concave groove 20 for placing the sealing ring is coaxially opened on the vent hole 18, and the sealing ring is embedded in this concave groove, and the gas path structure is suspended and fixed on the upper cover through a movable screw hole 24. A spring is also provided in the hole to provide the required pressure for the fit of the gas path and the sensor fixture 25, and the support structure 22 prevents the gas path and the sensor fixture 25 from being unevenly stressed after being pressed down. Therefore, based on the structure of the above-mentioned device, this embodiment provides the following method for use when testing the gas sensor, specifically when using 4 cavities, each cavity tests 8 sensors, specifically including the following steps: Step 1, take a sensor fixture 25, flip up and open the top pressure cover 4, place the MEMS sensor to be tested in the MEMS sensor limit groove 13, and ensure that the heating pole of the MEMS sensor corresponds to the heating pole on the connecting circuit board 9;

[0060] Step 2: Flip the top cover 4 downward and buckle it with the buckle 1, then plug and install the claw spring socket 8 on the signal conversion circuit board 30 to complete the installation of the MEMS sensor. Install 8 sensors in this way;

[0061] Step 3: According to the response resistance of the MEMS sensor to be tested, select a load board with a similar response resistance, and insert it into the load board socket 26, then cover the cavity cover so that the vent hole 18 on the gas path structure 33 is tightly pressed with the top pressure cover 4, so that the top vent hole 3 is connected with the vent hole 18, and the buckle on the cavity cover is tightly fastened to the cavity;

[0062] Step 4: Install sensors on all four chambers according to step 3, connect the chamber to the programmable power supply and analog-to-digital conversion device through the input and output aviation plug 38, and adjust the flow control valve until the flow of the gas flow meter meets the test requirements, then insert the air pipe into the air inlet 32, and connect the air pipe of the air outlet 34 to the gas recovery device;

[0063] Step 5: Set the heating voltage and test voltage of the programmable power supply on the host computer, and obtain the test resistance of the sensor at the same time, then introduce the test gas, and test the sensor by directly observing the response state of the sensor through the host computer based on the principle that the sensor responds to the test gas;

[0064] Step 6: After the test is completed, stop ventilation, set the program-controlled power supply to cut off, open the cavity cover and take out the gas sensor.

[0065] The following examples are provided in this specific embodiment:

[0066] The multi-channel dynamic gas sensor detection device mainly consists of 4 chambers, 4 programmable power supplies, 1 analog-to-digital conversion device, 4 gas flow meters and a host computer. Figure 1

[0067] The analog-to-digital conversion device and the host computer are connected through the RS485 bus, and the slave address of the analog-to-digital conversion device is set to 1. The programmable power supply and the host computer are connected through the RS485 bus, and the slave addresses are set to 2, 3, 4, and 5 in sequence.

[0068] Up to 8 sensors can be placed in one device, such as MEMS sensors Figure 7 As shown, 4 devices can be equipped in parallel. MEMS sensors are usually used under heating conditions. The host computer can control the programmable power supply to control the heating voltage (0-5V) and test voltage (0-5V) of the MEMS sensor. The ideal response temperature of the MEMS sensor to hydrogen is 400℃. Figure 8 It can be seen that the heating voltage is 3V at 400℃, and the host computer can control the programmable power supply to output a heating voltage of 3V.

[0069] Through the voltage divider resistor load card resistance, the voltage on the voltage divider resistor is tested, and the voltage of the test resistor is calculated: the measured voltage is fed back to the host computer through the analog-to-digital conversion device, and the host computer calculates the measured resistance according to Formula 1.

[0070] Install sensors in all four chambers according to step 3 above. Connect the chamber to the programmable power supply and analog-to-digital converter. Adjust the flow control valve until the flow of the 4-way gas flow meter meets the test requirements. Insert the gas pipe into the chamber and connect the gas outlet to the gas recovery device.

[0071] The host computer sets the heating voltage of the programmable power supply to 3V and the test voltage to 5V. The host computer also obtains the test resistance of the sensor. The test gas is introduced, and the sensor responds to the test gas. The response status of the sensor can be directly observed on the host computer. Fig. 9 The horizontal axis represents the test time s, the vertical axis represents the response resistance Ω, the 8 color curves represent the response resistance of the 8 channel sensors, and the 5 descending intervals of the curve represent the hydrogen introduced at 5ppm, 10ppm, 20ppm, 50ppm, and 100ppm.

[0072] Table 1 Positive and negative ventilation response values ​​F of 8 channels

[0073]

[0074]

[0075] The calculation formula of the response value F is as follows:

[0076]

[0077] Where Rb represents the baseline, which is the resistance measured by the sensor in air; Rr represents the response resistance, which is the resistance measured by the sensor at a specific hydrogen concentration.

[0078] As shown in Table 1, two response values ​​Ff1 and Ff2 are taken for forward ventilation, and two response values ​​Fb1 and Fb2 are taken for reverse ventilation. The average value F1 and F2 are taken for the measured value; the change rate C of forward and reverse ventilation is:

[0079]

[0080] By observing C, the fluctuation range of C is less than 5%, which shows that the test results are stable.

[0081] After the test is completed, ventilation is stopped, the upper computer is set to cut off the program-controlled power supply, and the cavity cover is opened to take out the sensor.

[0082] In summary, the multi-channel dynamic gas sensor detection device and its use method of this embodiment can use dynamic gas to test gas sensors with gas mass heavier or lighter than air, uneven flow distribution and unstable airflow. A large number of sensor tests can be achieved to ensure air tightness, external air tightness, internal air tightness, controllable MEMS sensor heating current, controllable test voltage, convenient sensor testing, and easy to take and put.

[0083] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A multi-channel dynamic gas sensor detection device, characterized in that: include: A plurality of cavities, the cavities being used to accommodate a plurality of gas sensors to be tested; A plurality of programmable power supplies, wherein the plurality of programmable power supplies are electrically connected to the gas sensors in the plurality of cavities and are used to input heating voltage and test voltage to the gas sensors; An analog-to-digital conversion device, which is in communication connection with a plurality of gas sensors and is used to receive analog signals output by the gas sensors and convert them into digital signals for output; A host computer, which is in communication connection with the analog-to-digital conversion device, and is used to receive the digital signal output by the analog-to-digital conversion device, and analyze and process the digital signal to complete the test of the gas sensor; A gas diversion device is connected to an external gas source to divert the test gas and send it into the cavity. Several of the cavities are connected to a gas flow meter one by one to detect the gas flow flowing into the cavity through the gas flow meter.

2. The multi-channel dynamic gas sensor detection device according to claim 1, characterized in that: The cavity is composed of an upper cover and a bottom box. The upper cover is provided with an air inlet (32) and an air outlet (34). The upper cover is provided with an air path structure (33). The air path structure (33) is connected to the air inlet (32) and the air outlet (34). A signal processing circuit board is provided in the bottom box. Several gas sensors to be tested are installed side by side on the signal processing circuit board. When the upper cover is covered on the bottom box, the air outlet holes of the air path structure (33) correspond to the gas sensors one by one. An input and output aviation plug (38) is provided on the side wall of the bottom box. The input and output aviation plug (38) is connected to the analog-to-digital conversion device through a signal line. The signal processing circuit board is connected to the input and output aviation plug (38) so that the output signal is input into the analog-to-digital conversion device after passing through the input and output aviation plug (38).

3. The multi-channel dynamic gas sensor detection device according to claim 2, characterized in that: A plurality of circuit board mounting screw seats (36) in the shape of inverted trumpets are also provided in the bottom box, and the signal processing circuit board is mounted on the circuit board mounting screw seats (36) by means of bolts.

4. The multi-channel dynamic gas sensor detection device according to claim 3, characterized in that: A top cover bayonet arm (31) is fixed on the side edge of the upper side of the top cover, and both the air inlet (32) and the air outlet (34) are provided with a vent hole pagoda head (35), which is connected to the air path structure (33) by means of a pipe sleeve connected to the vent hole pagoda head (35).

5. The multi-channel dynamic gas sensor detection device according to claim 4, characterized in that: The signal processing circuit board comprises: A signal conversion circuit board (30), wherein a plurality of circuit board positioning holes (27) are formed on the signal conversion circuit board (30), and the signal conversion circuit board (30) is fixed by means of bolts passing through the circuit board positioning holes (27) and being threadedly connected to the mounting screw seats (36); A plurality of sensor fixtures (25), wherein the plurality of sensor fixtures (25) are mounted side by side on a signal conversion circuit board (30) and are used to mount gas sensors to be tested side by side; A load board socket (26) is fixedly mounted on the signal conversion circuit board (30) and is used for mounting the load board; The power input socket (28) is fixedly mounted on the signal conversion circuit board (30) and is used for plugging in a power line; the signal output socket (29) is fixedly mounted on the signal conversion circuit board (30) and is used for plugging in a signal line.

6. The multi-channel dynamic gas sensor detection device according to claim 5, characterized in that: The sensor fixture (25) comprises a connecting circuit board (9), a base (10) and a top pressure cover (4); the connecting circuit board (9) is fixedly mounted on the lower side of the base (10) so as to be electrically connected to a gas sensor mounted between the base (10) and the top pressure cover (4); a MEMS sensor limiting groove (13) is provided in the base (10); one end of the top pressure cover (4) is hingedly mounted on the side of the base (10) so as to be flipped upward to open the MEMS sensor limiting groove (13) or flipped downward to close the MEMS sensor limiting groove (13); a top vent hole (3) is provided on the top pressure cover (4); the top vent hole (3) is used to be connected to the corresponding air outlet hole of the air path structure (33) when the upper cover is covered on the bottom box.

7. The multi-channel dynamic gas sensor detection device according to claim 6, characterized in that: A plurality of cross pins (7) are plugged into the lower side of the connecting circuit board (9), and claw spring sockets (8) are coaxially fixed to the lower ends of the plurality of cross pins (7). The claw spring sockets (8) are plugged and installed on the signal conversion circuit board (30) to fix the connecting circuit board (9) to the signal conversion circuit board (30) and electrically connect the connecting circuit board (9) to the signal conversion circuit board (30).

8. The multi-channel dynamic gas sensor detection device according to claim 7, characterized in that: A top pressure cover spring (5) is installed on a hinge shaft at one end of the top pressure cover (4) hinged to the base (10) to provide elastic force for driving the top pressure cover (4) to flip down. A buckle (1) is hinged at one end of the top pressure cover (4) facing away from the top pressure cover spring (5). A lever is formed at one end of the buckle (1) and a buckle clip (12) is formed at the other end. The buckle clip (12) is a barb structure. A buckle groove is provided on the side wall of the base (10). When the top pressure cover (4) flips down, the buckle (1) flips downward and the buckle clip (12) hooks the buckle groove. A buckle spring (14) is provided at the hinge between the buckle (1) and the top pressure cover (4) to provide elastic force for driving the buckle (1) to flip downward.

9. The multi-channel dynamic gas sensor detection device according to claim 8, characterized in that: The air path structure (33) comprises an air path pipeline (19), an air inlet (15) and an air outlet (21) provided at both ends of the air path pipeline (15), and a plurality of air vents (18) provided on the side wall of the air path pipeline (15), wherein the air vents (18) serve as air outlets of the air path structure (33), and an air path channel (23) is provided in the air path pipeline (19) and passes through both ends thereof, wherein the air inlet (15) and the air outlet (21) are respectively connected to the air inlet (32) and the air outlet (34) through pipelines, and the plurality of air vents (18) are connected to the air inlet (15) and the air outlet (21) through pipelines. The air holes (18) are evenly arranged on the side wall of the air pipeline (19) along the length direction of the air pipeline (19); a support structure (22) is fixed on the side of the air pipeline (19) facing away from the air holes (18); a positioning seat (17) is fixed on the support structure (22); a movable screw hole (24) is provided on the positioning seat (17); the support structure (22) is installed on the upper cover with the air pipeline (19) in a manner that a bolt with a spring passes through the movable screw hole (24) and is threadedly connected to the upper cover.

10. A method for using the detection device according to claim 9, characterized in that: The steps include: Step 1, take a sensor fixture (25), flip up and open the top cover (4), place the MEMS sensor to be tested in the MEMS sensor limit groove (13), and ensure that the heating electrode of the MEMS sensor corresponds to the heating electrode on the connecting circuit board (9); Step 2: flip the top cover (4) downward and fasten it with the buckle (1), then plug and install the claw spring socket (8) on the signal conversion circuit board (30) to complete the installation of the MEMS sensor; Step 3: According to the response resistance of the MEMS sensor to be tested, a load board with a similar response resistance is selected and inserted into the load board socket (26), and then the cavity cover is covered so that the vent hole (18) on the gas path structure (33) is tightly pressed with the top pressure cover (4), so that the top vent hole (3) is connected with the vent hole (18); Step 4: Connect the cavity to the programmable power supply and the analog-to-digital conversion device through the input and output aviation plug (38), and adjust the flow control valve until the flow rate of the gas flow meter meets the test requirements, then insert the air pipe into the air inlet (32), and connect the air pipe of the air outlet (34) to the gas recovery device; Step 5: Set the heating voltage and test voltage of the programmable power supply on the host computer, and obtain the test resistance of the sensor at the same time, then introduce the test gas, and test the sensor by directly observing the response state of the sensor through the host computer based on the principle that the sensor responds to the test gas; Step 6: After the test is completed, stop ventilation, set the program-controlled power supply to cut off, open the cavity cover and take out the gas sensor.

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