Testing device for detecting gas-sensitive sensing material in simulated diffusion mode
Technical Field
The invention relates to the technical field of gas detection, in particular to a gas sensitive material testing device for simulating diffusion type detection conditions.
Background
With the rapid development of material synthesis technology and semiconductor manufacturing process, various novel gas-sensitive sensing materials with better performance come out one after another, and more possibilities are provided for breaking through the bottleneck of the traditional gas detection technology. Meanwhile, the novel materials and devices also provide higher requirements for gas-sensitive analysis and test equipment, and the matched analysis and test device and instrument also need to optimize and improve the gas-sensitive materials with corresponding characteristics so as to meet the test requirements.
Most of the existing gas sensitive material testing devices need to vacuumize a cavity before testing, and then a certain amount of gas to be tested after calculation is introduced, so as to achieve the gas concentration required by testing. The testing device and the method have three operations which are easy to generate errors: firstly, the vacuumizing effect has high requirements on the sealing performance of a vacuum pump and a device; secondly, after a certain amount of gas to be measured is introduced, other gases are required to be introduced for the purpose that the air pressure in the cavity is generally normal pressure, and other gases are required to be introduced for balancing the air pressure value; and thirdly, materials such as the gas source, the gas pipeline, the cavity wall and the like which can contact the gas to be detected can generate an adsorption effect on the gas, the adsorption quantity cannot be calculated, when the gas which is easy to adsorb such as ammonia gas is tested, the actual gas concentration in the cavity can be far lower than a theoretical calculated value, and a large error can be generated when the response characteristic of the gas-sensitive sensing material is established.
On the other hand, some existing gas-sensitive sensing materials have response characteristics different from those of conventional gas sensors, the response value of the conventional gas sensor cannot generate large fluctuation due to the change of the flow of the gas to be detected, and the response steady-state value only has a certain functional relationship with the concentration of the gas to be detected. However, in a test experiment, it is found that the adsorption capacity of some gas-sensitive sensing materials to the gas molecules to be detected is far greater than the desorption capacity, and for such materials, if a pumping detection condition is adopted, the response value of the gas-sensitive sensing materials to be detected is continuously changed when the gas-sensitive sensing materials are continuously and directly blown to the gas to be detected, and the change rate is increased along with the increase of the gas flow rate. The velocity of gas molecules adsorbed on the surface of the material is far higher than the desorption velocity, the response time of the material reaching a stable state exceeds more than 10 times of the normal time, the final response steady-state value has no any significance, even possibly exceeds the maximum range of a detection instrument, and a functional relation cannot be established with the concentration of the gas to be detected.
The patent with the application number of CN204855490U discloses a multifunctional gas sensor test system, is used for preparing standard concentration test gas in a gas distribution chamber through a gas distribution mechanism and a vacuum pump, can realize the quick contact of a sensor and the standard gas through automatically preparing the standard concentration gas, and can also control the temperature and humidity of a sensor test environment.
The patent with application number CN204855490U discloses a gas sensor testing system, which has a "cross flow gas distribution" function, and can avoid the fluctuation of the total gas flow in the pipeline during the switching process, thereby causing the disturbance of the pressure and temperature of the gas-sensitive measuring device. However, the system still adopts the concept of 'pre-calculation and accurate gas distribution' to match the gas to be detected, and because the pipelines are more and complicated, the error generated by the adsorption of the gas to be detected by the pipelines cannot be ignored, and the 'accumulation effect' caused by the gas flow direct blowing of the gas sensing material cannot be avoided.
Disclosure of Invention
In order to solve the technical problem, the invention discloses a testing device for detecting a gas-sensitive sensing material in an analog diffusion mode.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a testing arrangement of simulation diffusion formula detection gas sensitive sensing material, includes the gas mixing chamber, installs in inside multichannel gas sensitive sensing monitor and the gas detector of gas mixing chamber, multichannel gas sensitive sensing monitor top still is provided with the vortex part.
As a further preferred aspect of the present invention, a plurality of gas path interfaces are disposed on a sidewall of the gas mixing chamber, each gas path interface is connected to one gas path valve, the gas path interface located at an upper portion of the gas mixing chamber is an air inlet gas path interface, the gas path interface located at a lower portion of the gas mixing chamber is an air exhaust gas path interface, the first gas tank and the second gas tank are both connected to a dynamic gas distribution instrument, the dynamic gas distribution instrument is connected to the gas path valve on the air inlet gas path interface through a pipeline, and the gas analysis device is connected to the gas path valve on the air exhaust gas path interface through a pipeline.
As a further preferable mode of the present invention, the gas mixing chamber includes a chamber, a fan and a cover plate, the fan is disposed at the middle upper portion of the chamber, a cylindrical rod with a screw thread is disposed above the cover plate, the motor is provided, and the blade driving shaft is disposed inside the cylindrical rod.
As a further preferred mode of the invention, the cylindrical rod penetrates through the cover plate through a round hole in the center of the cover plate, and the fan is fixedly and hermetically connected with the cover plate through a sealing gasket and another fixing nut.
As a further preferred aspect of the present invention, the top of the cavity and the circumferential outer circumference of the cover plate are both provided with a plurality of screw holes, the inner sides of the screw holes are both provided with annular grooves for fixing the gasket, and the cavity and the cover plate are fixedly connected through a plurality of screws and nuts.
As a further preferred aspect of the present invention, the bottom of the cavity is provided with three bases arranged in an equilateral triangle.
As a further preferable mode of the present invention, the turbulent flow member is a multi-layer bent structure, the gas sensitive sensing diaphragm is fixed inside the turbulent flow member, and the elastic metal electrode supports and fixes the gas sensitive sensing diaphragm.
As a further preferable mode of the invention, a plurality of groups of staggered hollow strips are arranged in the turbulence component.
As a further preferred aspect of the present invention, the elastic metal electrode is connected to a multi-channel gas sensitive monitor.
As a further preferred aspect of the present invention, the multichannel gas sensitive sensing monitor includes a gas sensitive sensing sheet, a monitor probe, a monitor main board, a monitor housing, and a battery, the gas sensitive sensing sheet and the monitor probe are in contact with each other through a slot, the monitor probe is connected to the monitor main body through a cable, a bluetooth module is disposed in the monitor, and monitoring data and temperature and humidity values are uploaded to an upper computer through a bluetooth technology.
As a further preferred aspect of the present invention, in the monitoring process of the multi-channel gas-sensitive sensing monitor, the gas-sensitive sensing sheet contacts with the gas to be measured, the target component in the gas to be measured chemically or physically reacts with the gas-sensitive sensing material to change the resistance value between the electrodes of the gas-sensitive sensing sheet, the monitor probe transmits the analog signal of the resistance value to the monitor motherboard, the analog signal is amplified and denoised by the conditioning circuit, then converted into a digital signal by the analog-to-digital conversion module and enters the central processing unit, and the central processing unit performs the conversion relationship between the preset resistance value variation and the concentration, the target gas concentration corresponding to the resistance value variation is preliminarily calculated, the resistance value variation is uploaded to the intelligent terminal and the network platform through the Bluetooth, and the terminal and the platform end correct the calculation relation in real time according to the big data to obtain more accurate target gas concentration.
As a further preferable mode of the present invention, the gas sensitive material sensing diaphragm is prepared by coating a gas sensitive material on an insulating substrate printed with interdigital electrodes by a chemical or physical method. The diaphragm is connected with the probe of the monitor through metal contact.
The beneficial effect of the invention is that,
1. by arranging the turbulence component, the phenomenon that high-flow-rate gas directly blows to the diaphragm to cause an accumulative effect is avoided, meanwhile, the elastic metal electrode can ensure good contact with the gas-sensitive sensing diaphragm, the measurement accuracy is ensured, the influence of gas flow on the response characteristic of the gas-sensitive sensing material is eliminated, and the universality is strong;
2. by arranging the gas online detector in the cavity, diffusion type detection conditions are completely simulated, so that the concentration error of gas to be detected in the cavity caused by gas distribution process operation, gas pipeline adsorption and other reasons can be avoided, and more accurate gas sensitive material sensing response can be obtained.
3. Compared with the existing testing device, the portable gas online detector is added in the cavity, so that the real concentration of gas in the cavity can be tested in real time, errors between the actual concentration of the gas to be tested and the preset concentration caused by calculation errors, gas source concentration errors, gas introduction amount errors, gas path adsorption errors and the like are eliminated, and the inaccurate response characteristic caused by the deviation of the response value of the gas sensitive material and the actual concentration of the gas to be tested is avoided.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention
FIG. 2 is a schematic view of the gas flow direction inside the gas mixing chamber of the present invention;
FIG. 3 is a schematic view of a spoiler structure according to the present invention;
FIG. 4 is a schematic view of a gas mixing chamber according to the present invention;
FIG. 5 is a schematic view showing a change curve of ammonia gas concentration with time in the chamber according to the example;
FIG. 6 is a graph showing a response curve plotted in the example.
Wherein, 1, a motor; 2-a screw; 3-cover plate; 4-a sealing gasket; 5-fixing the nut; 6-fan blades; 7-a sealing gasket; 8-a nut; 9-a cavity; 10-a base; 11-gas circuit valve; 12-gas path interface; 13-a resilient metal electrode; 14-hollow strips; 15-a flow perturbation component; 16-a multi-channel gas sensitive sensing monitor; 17-gas sensitive sensing diaphragm; 18-a gas detector; 19-dynamic gas distribution instrument; 20-a first gas tank; 21-a second gas tank; 22-a gas analysis device; 23-computer.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, a testing apparatus for detecting a gas-sensitive sensing material in an analog diffusion manner includes a gas mixing chamber, a multi-channel gas-sensitive sensing monitor 16 and a gas detector 18 installed inside the gas mixing chamber, wherein a spoiler 15 is further disposed above the multi-channel gas-sensitive sensing monitor 16; the side wall of the cavity 9 of the gas mixing cavity is provided with four gas circuit interfaces 12, each gas circuit interface 12 is connected with a gas circuit valve 11, the gas circuit valve 11 can open and close the gas circuit, three gas circuit interfaces 12 positioned on the upper part of the gas mixing cavity are gas inlet gas circuit interfaces 12 for introducing gas into the cavity 9, one gas circuit interface 12 positioned on the lower part of the gas mixing cavity is an exhaust gas circuit interface 12 for exhausting the gas in the cavity 9, the first gas tank 20 and the second gas tank 21 are both connected with a dynamic gas distribution instrument 19, the dynamic gas distribution instrument 19 is connected with the gas circuit valve 11 on the gas inlet gas circuit interface 12 through a pipeline, and the gas analysis device 22 is connected with the gas circuit valve 11 on the exhaust gas circuit interface 12 through a pipeline.
Specifically, the gas mixing chamber, as shown in fig. 4, includes a chamber 9, a fan and a cover plate 3, the fan is disposed at the middle upper portion of the chamber 9, a cylindrical rod with a thread is disposed above the cover plate 3 and has a motor 1, a blade driving shaft is disposed inside the cylindrical rod, the cylindrical rod passes through the cover plate 3 through a circular hole at the center of the cover plate 3, and the fan and the cover plate 3 are fixedly and hermetically connected through a sealing gasket 4 and another fixing nut 85; the installation mode eliminates the possibility that the electric part of the fan is contacted with the gas to be tested, enhances the safety of the experiment, and simultaneously, the blades of the fan are positioned at the middle upper part of the cavity 9, so that the gas in the cavity 9 can be quickly and uniformly subjected to convection mixing, and the gas in the cavity 9 can quickly reach the designated concentration.
FIG. 2 is a schematic view of the gas flow direction inside the gas mixing chamber. After entering the gas mixing cavity through the gas circuit interface 12 at the top, the gas directly enters the space below the fan blades 6, participates in the high-speed circulation of the gas inside the cavity 9 in the shortest time, and can ensure that the discharged gas at the bottom of the cavity 9 is the mixed uniform gas to the maximum extent.
Particularly, 8 screw holes are formed in the top of the cavity 9 and the circumference outer circumference of the cover plate 3, annular grooves for fixing sealing gaskets are formed in the inner sides of the screw holes, the silica gel sealing gaskets 7 are clamped in the grooves of the cavity 9 and the cover plate 3, and the cavity 9 and the cover plate 3 are fixedly connected through 8 screws 2 and nuts 8; the distribution mode ensures that the sealing gasket 7 is evenly stressed between the cover plate 3 and the cavity 9, and the top of the cavity 9 has good air tightness.
In particular, the bottom of the chamber 9 is provided with three bases 10 arranged in an equilateral triangle, for ensuring the stability of the fixed gas mixing chamber.
Particularly, the spoiler 15 is a multi-layer bent structure, the gas sensing diaphragm 17 is fixed inside the spoiler, and the elastic metal electrode 13 supports and fixes the gas sensing diaphragm 17. Particularly, a plurality of groups of staggered hollow strips 14 are arranged in the turbulence member 15, so that the flow velocity of gas can be obviously reduced, the gas with low flow velocity flows into the turbulence member 15, and the gas-sensitive membrane is prevented from generating an accumulation effect.
Fig. 3 is a schematic structural diagram of the spoiler 15, the elastic metal electrode 13 supports the gas-sensitive sensing diaphragm 17 and is fixed inside the spoiler 15, so that the phenomenon that high-flow-rate gas directly blows to the diaphragm to cause an accumulation effect is avoided, meanwhile, the elastic metal electrode 13 can ensure good contact with the gas-sensitive sensing diaphragm 17, and the measurement accuracy is ensured.
In particular, the flexible metal electrode 13 is connected to a multi-channel gas-sensitive monitor 16.
Particularly, the multi-channel gas-sensitive sensing monitor 16 is a portable multi-channel gas-sensitive sensing monitor 16 disclosed in CN201810428291.2, and comprises a gas-sensitive sensing sheet, a monitor probe, a monitor mainboard, a monitor shell and a battery, wherein the gas-sensitive sensing sheet and the monitor probe are contacted through a slot, the monitor probe is connected with a monitor main body through a cable, a bluetooth module is arranged in the monitor, and monitoring data and temperature and humidity values are uploaded to an upper computer through a bluetooth technology; in the monitoring process, the gas-sensitive sensing piece is contacted with gas to be detected, a target component in the gas to be detected and a gas-sensitive sensing material are subjected to chemical or physical reaction, the resistance value between the gas-sensitive sensing piece electrodes is changed, a monitor probe transmits an analog quantity signal of the resistance value to a monitor mainboard, the analog quantity is amplified and denoised through a conditioning circuit, the analog quantity is converted into a digital signal through an analog-to-digital conversion module and then enters a central processing unit, the central processing unit preliminarily calculates the target gas concentration corresponding to the change of the resistance value through a preset resistance value change quantity-concentration conversion relation, the resistance value change quantity is uploaded to an intelligent terminal and a network platform through Bluetooth, and the terminal and the platform end correct the calculation relation in real time according to big data to obtain more accurate target gas concentration.
Particularly, the gas sensitive material sensing diaphragm is prepared by coating a gas sensitive material on an insulating substrate printed with interdigital electrodes by a chemical or physical method, and the diaphragm is connected with a monitor probe through metal contact.
In addition, the gas analyzer 22 may select different instruments according to actual requirements, such as various gas analyzers, such as a gas chromatograph, a gas chromatograph-mass spectrometer, and optical detectors such as infrared/ultraviolet/laser, and select a suitable detection instrument according to a suitable detection principle of the target gas.
The first tank body and the second tank body are respectively filled with gas to be tested and environment bottom gas, as shown in figure 1, the gas to be tested and the environment bottom gas can be led into the gas mixing cavity after being fixedly proportioned by the dynamic gas distributing instrument 19 according to the experimental requirement, or directly introduced into the gas mixing cavity, a gas-sensitive sensing diaphragm 17 is fixed inside the turbulent flow component 15, the elastic metal electrode 13 is connected with a multi-channel gas sensitive sensing monitor 16, a portable gas detector 18 is arranged in a gas mixing cavity, the portable gas detector 18 can select a corresponding market model according to the type of the gas to be detected, the exhaust gas circuit at the bottom of the cavity 9 can be connected to an online gas analysis device 22, for real-time monitoring of the composition and concentration of the exiting mixed gas, and a computer 23 for receiving and storing data from the multi-channel gas sensor monitor 16, the portable gas detector 18, and the gas analysis device 22.
Example 1
The following is an example of the performance test experiment of the ammonia gas-sensitive membrane.
The test procedure was as follows:
1. preparing 100ppm ammonia standard gas and compressed air standard gas, respectively accessing into a dynamic gas distribution instrument 19, and accessing the output end of the dynamic gas distribution instrument 19 into a gas path valve 11 on a gas inlet gas path interface 12 at the upper part of a gas mixing cavity;
2. the ammonia gas-sensitive film is propped against by the elastic metal electrode 13 and is fixed inside the turbulence component 15, and the exposed end of the elastic metal electrode 13 is connected with the multi-channel gas-sensitive sensing monitor 16;
3. after the multi-channel gas-sensitive sensing monitor 16 is started, the multi-channel gas-sensitive sensing monitor is connected with a computer 23 through Bluetooth, the resistance value of the gas-sensitive film is sent to the computer 23 in real time, the turbulence component 15 and the multi-channel gas-sensitive sensing monitor 16 are placed at the bottom of a gas mixing cavity, meanwhile, a portable ammonia gas detector is placed at the bottom of the gas mixing cavity after the multi-channel gas-sensitive sensing monitor is started, and the model of the ammonia gas detector is a GAXT-A ammonia gas detector of Canada BW company and is used for observing the;
4. closing the rest gas circuit valves 11 on the unused gas inlet gas circuit interface 12, and opening the gas circuit valves 11 on the exhaust gas circuit interface 12 at the bottom of the gas mixing cavity;
in the experimental process, the dynamic gas distributor 19 is controlled to introduce mixed gas with the ammonia concentration of 50ppm into the cavity 9, the flow rate is 0.5L/min, the total volume of the gas mixing cavity is 28.3L, the mixed gas is continuously introduced, the reading C of the portable ammonia detector 18 is observed and recorded according to the frequency of 30s, the time change curve of the ammonia concentration in the cavity 9 of the gas mixing cavity is drawn as shown in figure 5, the response value V of the multi-channel gas-sensitive sensing monitor 16 is received at the end of the computer 23, the sampling frequency is set to be 10s, the response curve is drawn as shown in figure 6, the V is used as the input quantity x, the C is used as the output quantity y, and function fitting is carried out to obtain the response characteristic of the ammonia sensing diaphragm.
Taking the first order function as an example, the fitting result is:
y=0.8985x+0.1263
the function can represent the response characteristic curve of the ammonia gas sensitive sensing diaphragm 17.
Example 2
The following is an example of the performance test experiment of the ammonia gas-sensitive membrane.
The test procedure was as follows:
1. preparing 120ppm ammonia standard gas and compressed air standard gas, respectively accessing into a dynamic gas distribution instrument 19, and accessing the output end of the dynamic gas distribution instrument 19 into a gas path valve 11 on a gas inlet gas path interface 12 at the upper part of a gas mixing cavity;
2. the ammonia gas-sensitive film is propped against by the elastic metal electrode 13 and is fixed inside the turbulence component 15, and the exposed end of the elastic metal electrode 13 is connected with the multi-channel gas-sensitive sensing monitor 16;
3. after the multi-channel gas-sensitive sensing monitor 16 is started, the multi-channel gas-sensitive sensing monitor is connected with a computer 23 through Bluetooth, the resistance value of the gas-sensitive film is sent to the computer 23 in real time, the turbulence component 15 and the multi-channel gas-sensitive sensing monitor 16 are placed at the bottom of a gas mixing cavity, meanwhile, a portable ammonia gas detector is placed at the bottom of the gas mixing cavity after the multi-channel gas-sensitive sensing monitor is started, and the model of the ammonia gas detector is a GAXT-A ammonia gas detector of Canada BW company and is used for observing the;
4. closing the rest gas circuit valves 11 on the unused gas inlet gas circuit interface 12, and opening the gas circuit valves 11 on the exhaust gas circuit interface 12 at the bottom of the gas mixing cavity;
in the experimental process, the dynamic gas distributor 19 is controlled to introduce mixed gas with the ammonia concentration of 60ppm into the cavity 9, the flow rate is 0.4L/min, the total volume of the gas mixing cavity is 28.3L, the mixed gas is continuously introduced, the reading C of the portable ammonia detector 18 is observed and recorded according to the frequency of 20s, a time change curve of the ammonia concentration in the cavity 9 of the gas mixing cavity is drawn, the response value V of the multi-channel gas-sensitive sensing monitor 16 is received at the end of the computer 23, the sampling frequency is set to be 8s, the response curve is drawn as shown in figure 6, the V is used as the input quantity x, the C is used as the output quantity y, and function fitting is carried out, so that the response characteristic of the ammonia sensing diaphragm can be obtained.
Example 3
The following is an example of the performance test experiment of the ammonia gas-sensitive membrane.
The test procedure was as follows:
1. preparing 80ppm ammonia standard gas and compressed air standard gas, respectively accessing into a dynamic gas distribution instrument 19, and accessing the output end of the dynamic gas distribution instrument 19 into a gas path valve 11 on a gas inlet gas path interface 12 at the upper part of a gas mixing cavity;
2. the ammonia gas-sensitive film is propped against by the elastic metal electrode 13 and is fixed inside the turbulence component 15, and the exposed end of the elastic metal electrode 13 is connected with the multi-channel gas-sensitive sensing monitor 16;
3. after the multi-channel gas-sensitive sensing monitor 16 is started, the multi-channel gas-sensitive sensing monitor is connected with a computer 23 through Bluetooth, the resistance value of the gas-sensitive film is sent to the computer 23 in real time, the turbulence component 15 and the multi-channel gas-sensitive sensing monitor 16 are placed at the bottom of a gas mixing cavity, meanwhile, a portable ammonia gas detector is placed at the bottom of the gas mixing cavity after the multi-channel gas-sensitive sensing monitor is started, and the model of the ammonia gas detector is a GAXT-A ammonia gas detector of Canada BW company and is used for observing the;
4. closing the rest gas circuit valves 11 on the unused gas inlet gas circuit interface 12, and opening the gas circuit valves 11 on the exhaust gas circuit interface 12 at the bottom of the gas mixing cavity;
in the experimental process, the dynamic gas distributor 19 is controlled to introduce mixed gas with the ammonia concentration of 40ppm into the cavity 9, the flow rate is 0.6L/min, the total volume of the gas mixing cavity is 28.3L, the mixed gas is continuously introduced, the reading C of the portable ammonia detector 18 is observed and recorded according to the frequency of 40s, the time change curve of the ammonia concentration in the cavity 9 of the gas mixing cavity is drawn as shown in figure 5, the response value V of the multi-channel gas-sensitive sensing monitor 16 is received at the end of the computer 23, the sampling frequency is set to be 20s, the response curve is drawn as shown in figure 6, the V is used as the input quantity x, the C is used as the output quantity y, and function fitting is carried out to obtain the response characteristic of the ammonia sensing diaphragm.
Aiming at the problems that the conventional gas-sensitive sensing material testing device cannot strictly create a simulated diffusion type sampling environment with given concentration and has errors in performance testing of partial gas-sensitive sensing materials, the invention designs the gas-sensitive sensing material testing device for simulating diffusion type detection conditions, which can monitor the concentration of gas to be tested in the device in real time, send the response characteristic of the material to an upper computer outside the device through wireless transmission, eliminate the influence of gas flow on the response characteristic of the gas-sensitive sensing materials by designing the turbulent flow component 15, has stronger universality and can improve the testing accuracy of the gas-sensitive sensing materials.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.