CN115386474A - Carbon dioxide incubator and its concentration control method - Google Patents

Abstract

The invention provides a carbon dioxide incubator and a concentration control method thereof, wherein the incubator comprises a controller, and an air inlet of the incubator is communicated with a carbon dioxide air path, an air path and a balance air path; the balance gas is air with carbon dioxide removed; the air source of the balance air path is an air processing device communicated with the air path; the gas treatment device comprises a gas washing container and a drying container; air input into the gas washing container from the air gas path is subjected to carbon dioxide removal treatment in the gas washing container, and then is introduced into the drying container to remove moisture to form balance gas; the carbon dioxide gas circuit, the air gas circuit and the balance gas circuit are all provided with electromagnetic valves which are used for controlling the flow of the gas circuits and are connected with the controller; according to the invention, pure carbon dioxide gas, air and air (balance gas) with carbon dioxide removed are used as gas input of the incubator, and the accurate control of the concentration of carbon dioxide within the range of 200-10000ppm can be realized by closed-loop control of the corresponding three electromagnetic valves through the Smith prediction control module.

Description

Carbon dioxide incubator and its concentration control method

technical field

The invention relates to the technical field of animal and plant incubators, in particular to a carbon dioxide incubator and a concentration control method thereof.

Background technique

In agricultural and life science research and production, gas incubators are usually used to obtain growth data and results of organisms under certain gas set concentrations, and carbon dioxide incubators are one of the common ones. During the cultivation process, the carbon dioxide concentration in the box is required to be kept constant or to change according to the set curve, which requires the incubator to be able to independently adjust the carbon dioxide concentration in the box, and be lower or higher than the carbon dioxide concentration in the air (400ppm) .

A common low-concentration carbon dioxide incubator technical solution is to use carbon dioxide adsorbent to circulate and filter the gas in the box to reduce the carbon dioxide concentration in the gas. The technical scheme of the high-concentration carbon dioxide incubator is to fill the incubator with carbon dioxide gas through a high-pressure carbon dioxide cylinder to increase its concentration.

In the above-mentioned low-concentration technical solution, the entire system can only actively reduce the carbon dioxide concentration in the tank, but cannot actively increase it. If too much carbon dioxide is absorbed during circulation, resulting in too low concentration in the incubator, or the set value is higher than the current value in the incubator, this solution will take a long time to adjust, and even cannot be adjusted to the target value, resulting in the entire incubator being unusable .

In the above-mentioned high-concentration technical solution, to reduce the concentration of carbon dioxide in the tank, it can only be achieved by filling the tank with air, which makes the lowest concentration of carbon dioxide in the tank only the same as that of air, about 400ppm, and cannot reach low concentration requirements. At the same time, in this patent, there is only an air inlet between the inside of the box and the outside atmosphere, and there is no air outlet. This will cause the air pressure in the box to be too high during actual use, so that it cannot be used normally.

Contents of the invention

The present invention proposes a carbon dioxide incubator and its concentration control method. Pure carbon dioxide gas, air, and air (balanced gas) from which carbon dioxide has been filtered are used as the gas input of the incubator, and the corresponding three solenoid valves are controlled by the closed-loop control of the Smith estimation control module. Complete the high-sensitivity control of carbon dioxide in the box, can realize the precise control of carbon dioxide concentration in the range of 200-10000ppm, and can also adjust independently according to the concentration curve set in advance, with good application flexibility.

The present invention adopts the following technical solutions.

A carbon dioxide incubator, the incubator (20) includes a controller (21), and the controller (21) is used to The carbon dioxide concentration signal collected in real time controls the opening and closing of the first solenoid valve (3), the second solenoid valve (5) and the third solenoid valve (6), so as to adjust the carbon dioxide concentration inside the carbon dioxide incubator; The air inlet of the incubator communicates with the carbon dioxide gas path, the air gas path, and the balance gas path; the balance gas is air that has filtered carbon dioxide; the gas source of the balance gas path is a gas processing device that communicates with the air path The gas processing device includes a gas scrubbing container (7) and a drying container (8); the air input into the gas scrubbing container from the air path is subjected to carbon dioxide removal treatment in the gas scrubbing container, and then passed into the drying container to remove moisture To form a balance gas; the carbon dioxide gas circuit, the air gas circuit, and the balance gas circuit are all equipped with electromagnetic valves for controlling the flow of the gas circuit and connected to the controller.

The carbon dioxide gas path includes the first intake pipe (12), the first electromagnetic valve (3), the pressure reducing valve (2), and the carbon dioxide cylinder (1) connected in sequence; when the first electromagnetic valve is turned on, the carbon dioxide Gas cylinders input high-pressure pure carbon dioxide gas into the incubator;

The air circuit includes a second air intake pipe (13), a second solenoid valve (5) and an air pump (4) connected in sequence; when the second solenoid valve is turned on, the air pump inputs external air to the incubator;

The balance gas circuit includes a third intake pipe (14), a third solenoid valve (6), a one-way valve (9), and a gas processing device connected in sequence; the one-way valve is located at the output end of the gas processing device To prevent gas backflow; when the third solenoid valve is turned on, the air pump inputs external air to the gas washing container, so that the gas processing device can generate balance gas and input it into the incubator.

The incubator includes a connector, an air inlet (11) and an air outlet (18); one port of the connector (10) communicates with the air inlet, and the remaining ports of the connector are respectively connected with the first air inlet pipe, the second air inlet The two air inlet pipes and the third air inlet pipe are connected; the top of the incubator is provided with a fan (15) for mixing the gas in the incubator; the gas outlet is provided with a manual proportional adjustment for adjusting the rate of gas output in the incubator valve (19); the controller is connected with the touch display screen (22).

The controller is connected with the first sensor (16) and the second sensor (17) in the incubator to detect the carbon dioxide concentration in the incubator in real time and determine the mixing uniformity of the carbon dioxide in the incubator. The sensor (23) is connected to detect the carbon dioxide concentration of the air input into the incubator by the air path in real time;

The controller controls the first solenoid valve, the second solenoid valve and the third solenoid valve according to the detection data of the first sensor, the second sensor and the third sensor, so as to control the concentration of carbon dioxide gas in the incubator.

The NaOH solution for absorbing carbon dioxide is stored in the gas scrubbing container; the gas inlet pipe outlet of the gas scrubbing container is porous and immersed in the NaOH solution; the drying container is filled with CaO crystals.

The control method of the carbon dioxide incubator with controllable concentration uses the above-mentioned incubator, and the control method includes the following contents;

Method A. Initially, the controller firstly sets the required carbon dioxide concentration C ₁ inside the incubator; secondly, at the beginning of each control cycle, the controller obtains the detection values of the first sensor and the second sensor, and calculates Obtain the average value _C2 of the carbon dioxide concentration of the two sensors as the current concentration of carbon dioxide gas in the box, and at the same time obtain the value _C3 of the carbon dioxide concentration of the third sensor; then the controller determines by comparing the values of _C1 , _C2 and _C3 A corresponding control scheme is used to control the first solenoid valve, the second solenoid valve, and the third solenoid valve;

Method B. When the set value C ₁ is greater than or equal to the carbon dioxide concentration C ₃ of the outside air, inject natural air or pure carbon dioxide to increase the carbon dioxide concentration in the tank; during the injection process, when the set value C ₁ is higher than the concentration in the tank When the average C ₂ is high and the difference is above 100ppm, the concentration in the tank can be rapidly increased by controlling the first solenoid valve to inject pure carbon dioxide; otherwise, open the second solenoid valve to inject external air, or open the third solenoid valve to inject balance gas , to increase or decrease the carbon dioxide concentration in the tank to stabilize it at the set value;

Method C. When the set value C ₁ is less than the carbon dioxide concentration C ₃ of the outside air, the carbon dioxide concentration in the box is reduced by injecting natural air or air without carbon dioxide at this time; during the injection process, when the average concentration in the box is C ₂ When it is higher than the set value C ₁ and the difference is more than 100ppm, the concentration in the tank can be reduced faster by controlling the third solenoid valve to inject balance gas; otherwise, inject carbon dioxide by opening the first solenoid valve, or open the second solenoid valve to inject External air is used to increase or decrease the carbon dioxide concentration in the tank to stabilize it at the set value.

After the controller has determined the solenoid valve to be controlled, the set value _C1 and the concentration average value _C2 are input into the Smith predictive control module, and the conduction time of the corresponding solenoid valve is calculated; the Smith predictive The estimated control module is to introduce a Smith predictor at both ends of the traditional PI controller, which together with the PI controller constitutes the Smith predictive control module, which is used to compensate the hysteresis effect from the conduction of the solenoid valve to the input gas to the uniform gas mixing in the box. The error formed by the adjustment of carbon dioxide concentration to speed up the adjustment speed; finally, the controller controls the action of the solenoid valve according to the conduction time, injects gases with different carbon dioxide concentrations through the three intake pipes, and then adjusts the carbon dioxide concentration in the box, and then waits for the next The arrival of the control cycle.

The first solenoid valve, the second solenoid valve and the third solenoid valve are all on-off solenoid valves.

When the pressure of carbon dioxide in the carbon dioxide cylinder is still high after being decompressed by the decompression valve, the following method is used to continue the decompression, that is: when controlling the first solenoid valve, the control cycle is divided into multiple periods according to the fixed conduction interval , the conduction time calculated by the Smith predictive control module is converted into the corresponding number of periods, so that the first solenoid valve is only conducted for a fixed period of time in these periods, and the carbon dioxide gas is output to the incubator with a small amount and multiple frequencies to reduce Small air pressure; during the remaining off-time beyond the calculated on-time, the first solenoid valve will remain off.

The human-computer interaction interface of the controller includes a touch screen, when different carbon dioxide gas concentrations are required at different time periods, the set curve is input through the touch screen, and the controller adjusts the first solenoid valve in real time according to the curve ( 3). The second solenoid valve (5) and the third solenoid valve (6) make the carbon dioxide concentration in the tank change according to the set curve.

In the present invention, pure carbon dioxide gas, air, and air with carbon dioxide filtered out are used as the gas input of the incubator, and the three solenoid valves corresponding to the closed-loop control of the Smith estimation control module are used to complete the high-sensitivity control of carbon dioxide in the box, and can realize 200- The carbon dioxide concentration within the range of 10000ppm can be precisely controlled, and can also be adjusted independently according to the concentration curve set in advance, which has good application flexibility. Compared with the existing technical solutions, the present invention can realize both low concentration control and high concentration control.

The present invention controls the input of three kinds of gases in stages through the method of segmented control, and the additionally added third sensor can ensure the effectiveness of the regulation; introduces the pure lag of the Smith predictor to compensate the control process, and combines the PI controller to form the Smith predictor The control module has a good control effect on the technical solution of the incubator proposed by the present invention, and at the same time can reduce the consumption speed of consumables and reduce the use cost.

In the control strategy of the first electromagnetic valve connected to the carbon dioxide gas cylinder, the present invention uses a fixed conduction interval to divide the algorithm period, and converts the calculated conduction time to avoid the impact of high-pressure pure carbon dioxide gas on the gas in the box. The impact of the concentration makes the control process smoother. At the same time, this control method can use a low-cost common on-off solenoid valve, which can effectively reduce the manufacturing cost of the device.

Since the technical solution proposed by the present invention has good controllability for the carbon dioxide concentration of the incubator, when setting the carbon dioxide concentration of the incubator, in addition to the traditional fixed numerical control, a set curve can also be input through the touch screen, The controller will adjust in real time according to the curve, so that the carbon dioxide concentration in the box changes according to the curve. This adjustment method is suitable for those biological cultures that require different gas concentrations at different times.

The present invention uses three kinds of gases with different carbon dioxide concentrations to carry out segmental control, which can effectively prolong the use time of consumables such as carbon dioxide cylinders and gas washing cylinders, and reduce the use cost of the entire device. At the same time, this subsection control can also make the system fluctuate less and the convergence time shorter when the set value converges. In addition, the external third sensor can collect the carbon dioxide concentration of the pumped air in real time to ensure the effectiveness of the natural air sent through the second air intake pipe in regulating the gas concentration in the box.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

Accompanying drawing 1 is the device structural representation of the present invention;

Accompanying drawing 2 is the electrical structure schematic diagram of the present invention;

Accompanying drawing 3 is the control flow schematic diagram of the present invention;

Accompanying drawing 4 is the algorithm structure schematic diagram of Smith predictive control module of the present invention;

Accompanying drawing 5 is the conduction logic schematic diagram of the first electromagnetic valve;

In the figure: 1-carbon dioxide cylinder, 2-pressure reducing valve, 3-first solenoid valve, 4-air pump, 5-second solenoid valve, 6-third solenoid valve, 7-gas scrubbing container, 8-drying container , 9-one-way valve, 10-connector, 11-air inlet, 12-first air inlet pipe, 13-second air inlet pipe, 14-third air inlet pipe, 15-fan, 16-first Sensor, 17-second sensor, 18-air outlet, 19-manual proportional regulating valve, 20-incubator, 21-controller, 22-touch display screen, 23-third sensor.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

The flow charts shown in the drawings are just illustrations, and do not necessarily include all contents and operations/steps, nor must they be performed in the order described. For example, some operations/steps can be decomposed, combined or partly combined, so the actual order of execution may be changed according to the actual situation.

It should be understood that the terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit the application. As used in this specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural referents unless the context clearly dictates otherwise.

It should be understood that in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with basically the same function and effect . For example, the first recognition model and the second recognition model are only used to distinguish different callback functions, and their sequence is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the number and execution order, and words such as "first" and "second" do not necessarily limit the difference.

It should also be understood that the term "and/or" used in the description of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations .

In order to facilitate understanding of the embodiments of the present application, some terms involved in the embodiments of the present application are briefly described below.

1. PPM, the abbreviation of parts per million, the unit of gas concentration, parts per million.

2. Gas washing, the process of removing impurity gas in the mixed gas.

3. The incubator refers to a box device with adjustable and controllable parameters, which is mainly used for cultivating microorganisms, plants and animal cells.

4. Solenoid valve, which belongs to actuator, is an industrial equipment controlled by electromagnetic, and it is an automatic basic component used to control fluid. The on-off solenoid valve control has only two states: fully open and fully closed.

Existing carbon dioxide incubators have the disadvantages of being unable to lower the carbon dioxide concentration, or destroying the ratio of other gas components in the air, or having low accuracy and rapidity of carbon dioxide control.

To this end, the embodiments of the present application provide a carbon dioxide incubator and a method for controlling its concentration. Through the invention of the device and the supporting control method, the carbon dioxide concentration of the air in the incubator can be flexibly adjusted by scrubbing and injecting pure carbon dioxide gas without changing other gas components in the air, and further invented the control cycle according to a fixed guide. The on-off interval is divided into multiple time periods, and the on-time calculated by the control algorithm will be converted into the corresponding number of time periods. The method realizes Smith's predictive control execution, ensuring that the invention can control the on-off of the low-cost solenoid valve to achieve carbon dioxide within the range of 200-10000PPM Accurate and fast adjustment of concentration.

Some implementations of the present application will be described in detail below in conjunction with the accompanying drawings. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

As shown in the figure, a carbon dioxide incubator, the incubator 20 includes a controller 21, the controller 21 is used to collect real-time carbon dioxide concentration signals according to the first sensor 16, the second sensor 17 and the third sensor 23, Control the opening and closing of the first solenoid valve 3, the second solenoid valve 5 and the third solenoid valve 6 to adjust the internal carbon dioxide concentration of the carbon dioxide incubator; , the balance gas path is communicated; the balance gas is the air that filters out carbon dioxide; the gas source of the balance gas path is a gas treatment device communicated with the air path; the gas treatment device includes a gas washing container 7 and a drying Container 8; the air that is input into the scrubbing container from the air gas path is subjected to carbon dioxide removal treatment in the gas scrubbing container, and then passed into a drying container to remove moisture to form a balance gas; the carbon dioxide gas path, the air gas path, and the balance gas The air path is equipped with a solenoid valve for controlling the flow of the air path and connected with the controller.

The carbon dioxide gas path includes the first air intake pipe 12, the first solenoid valve 3, the pressure reducing valve 2, and the carbon dioxide gas cylinder 1 connected in sequence; when the first solenoid valve is turned on, the carbon dioxide gas cylinder inputs high-pressure pure carbon dioxide gas;

The air circuit includes a second air intake pipe 13, a second solenoid valve 5 and an air pump 4 connected in sequence; when the second solenoid valve is turned on, the air pump inputs external air to the incubator;

The balance gas circuit includes a third intake pipeline 14, a third solenoid valve 6, a one-way valve 9, and a gas processing device connected in sequence; the one-way valve is located at the output end of the gas processing device to prevent gas from flowing backward; when After the third solenoid valve is turned on, the air pump inputs external air to the gas washing container, so that the gas processing device generates balance gas and inputs it into the incubator.

Described incubator comprises connector, air inlet 11 and air outlet 18; One port of connector 10 communicates with air inlet, and the remaining ports of connector are also respectively connected with the first air inlet pipe, the second air inlet pipe, the first air inlet pipe. The three inlet pipes communicate; the top of the incubator is provided with a fan 15 for mixing the gas in the box; the gas outlet is provided with a manual proportional regulating valve 19 for adjusting the rate of gas output in the incubator; the controller and The touch display screen 22 is connected.

The controller is connected with the first sensor 16 and the second sensor 17 in the incubator to detect the carbon dioxide concentration in the box in real time and determine the mixing uniformity of the carbon dioxide in the box, and is also connected with the third sensor 23 at the air pump inlet to Real-time detection of carbon dioxide concentration in the air input from the air path to the incubator;

The controller controls the first solenoid valve, the second solenoid valve and the third solenoid valve according to the detection data of the first sensor, the second sensor and the third sensor, so as to control the concentration of carbon dioxide gas in the incubator.

The NaOH solution for absorbing carbon dioxide is stored in the gas scrubbing container; the gas inlet pipe outlet of the gas scrubbing container is porous and immersed in the NaOH solution; the drying container is filled with CaO crystals.

The device proposed by the invention can flexibly adjust the carbon dioxide concentration of the air in the incubator within the range of 200-10000PPM by scrubbing and injecting pure carbon dioxide without changing other gas components in the air.

The control method of the carbon dioxide incubator with controllable concentration uses the above-mentioned incubator, and the control method includes the following contents;

Method A. Initially, the controller firstly sets the required carbon dioxide concentration C ₁ inside the incubator; secondly, at the beginning of each control cycle, the controller obtains the detection values of the first sensor and the second sensor, and calculates Obtain the average value _C2 of the carbon dioxide concentration of the two sensors as the current concentration of carbon dioxide gas in the box, and at the same time obtain the value _C3 of the carbon dioxide concentration of the third sensor; then the controller determines by comparing the values of _C1 , _C2 and _C3 A corresponding control scheme is used to control the first solenoid valve, the second solenoid valve, and the third solenoid valve;

Method B. When the set value C ₁ is greater than or equal to the carbon dioxide concentration C ₃ of the outside air, inject natural air or pure carbon dioxide to increase the carbon dioxide concentration in the tank; during the injection process, when the set value C ₁ is higher than the concentration in the tank When the average C ₂ is high and the difference is above 100ppm, the concentration in the tank can be rapidly increased by controlling the first solenoid valve to inject pure carbon dioxide; otherwise, open the second solenoid valve to inject external air, or open the third solenoid valve to inject balance gas , to increase or decrease the carbon dioxide concentration in the tank to stabilize it at the set value;

Method C. When the set value C ₁ is less than the carbon dioxide concentration C ₃ of the outside air, the carbon dioxide concentration in the box is reduced by injecting natural air or air without carbon dioxide at this time; during the injection process, when the average concentration in the box is C ₂ When it is higher than the set value C ₁ and the difference is more than 100ppm, the concentration in the tank can be reduced faster by controlling the third solenoid valve to inject balance gas; otherwise, inject carbon dioxide by opening the first solenoid valve, or open the second solenoid valve to inject External air is used to increase or decrease the carbon dioxide concentration in the tank to stabilize it at the set value.

After the controller has determined the solenoid valve to be controlled, the set value _C1 and the concentration average value _C2 are input into the Smith predictive control module, and the conduction time of the corresponding solenoid valve is calculated; the Smith predictive The estimated control module is to introduce a Smith predictor at both ends of the traditional PI controller, which together with the PI controller constitutes the Smith predictive control module, which is used to compensate the hysteresis effect from the conduction of the solenoid valve to the input gas to the uniform gas mixing in the box. The error formed by the adjustment of carbon dioxide concentration to speed up the adjustment speed; finally, the controller controls the action of the solenoid valve according to the conduction time, injects gases with different carbon dioxide concentrations through the three intake pipes, and then adjusts the carbon dioxide concentration in the box, and then waits for the next The arrival of the control cycle.

The first solenoid valve, the second solenoid valve and the third solenoid valve are all on-off solenoid valves.

When the pressure of carbon dioxide in the carbon dioxide cylinder is still high after being decompressed by the decompression valve, the following method is used to continue the decompression, that is: when controlling the first solenoid valve, the control cycle is divided into multiple periods according to the fixed conduction interval , the conduction time calculated by the Smith predictive control module is converted into the corresponding number of periods, so that the first solenoid valve is only conducted for a fixed period of time in these periods, and the carbon dioxide gas is output to the incubator with a small amount and multiple frequencies to reduce Small air pressure; during the remaining off-time beyond the calculated on-time, the first solenoid valve will remain off.

The human-computer interaction interface of the controller includes a touch screen, when different carbon dioxide gas concentrations are required at different time periods, the set curve is input through the touch screen, and the controller adjusts the first solenoid valve in real time according to the curve ( 3). The second solenoid valve (5) and the third solenoid valve (6) make the carbon dioxide concentration in the tank change according to the set curve.

In this example, the outside air passes through the gas washing bottle to remove the contained carbon dioxide, and then passes through the drying bottle to remove the excess moisture brought by the gas washing bottle, so that the third air intake pipe can input natural air without carbon dioxide into the incubator (i.e. balance gas). There is half a bottle of NaOH solution with a concentration of 75g/L in the gas scrubbing container. The air inlet pipe of the gas scrubbing bottle is submerged in the solution. Full reaction; the dry container is filled with CaO crystals; the one-way valve can prevent the gas in other pipelines from flowing back into the dry bottle and the gas washing bottle.

In this example, the gas outlet is connected with a manual proportional regulating valve, which is used to adjust the rate of gas output in the incubator, usually set at 50%.

In the control algorithm, since it takes a certain amount of time from the conduction of the solenoid valve to the gas mixing in the box, this time lag makes the application effect of traditional PID poor. As shown in Figure 4, in order to improve the control effect, the present invention introduces a Smith predictor at both ends of the traditional PI controller, and constitutes the Smith predictor control module together with the PI controller to compensate for the adjustment of the carbon dioxide concentration by this pure lag Adverse effects, speed up the adjustment speed.

In order to reduce the cost, the present invention adopts an on-off electromagnetic valve with lower cost. Since the conduction and shut-off of this electromagnetic valve all need a certain amount of time, because the carbon dioxide concentration and air pressure in the carbon dioxide gas cylinder are all high, even if the After passing through the decompression valve, the air pressure still has a relatively high value. If the first solenoid valve is fully turned on within the calculated conduction time, a large amount of high-pressure pure carbon dioxide gas influx will have an impact on the gas concentration inside the incubator. lead to roughness of the control process. Therefore, the present invention proposes the conduction logic shown in FIG. 5 and applies it to the control of the first solenoid valve. The present invention divides the control period into a plurality of periods according to the fixed conduction interval, and the conduction time calculated by the control algorithm will be converted into corresponding period numbers. In these periods, the first solenoid valve will only conduct for a fixed time; During the remaining off-time beyond the calculated on-time, the first solenoid valve will remain in the off state. This control method also reduces the overall output pressure of the carbon dioxide gas cylinder in a disguised form, and can avoid the impact of high-pressure pure carbon dioxide gas on the gas concentration inside the incubator. At the same time, the realization process can be realized by using a low-cost on-off solenoid valve.

The control module and implementation method proposed by the invention can respond to the setting of carbon dioxide concentration at low cost, accurately and quickly.

The above is only a specific embodiment of the application, but the scope of protection of the application is not limited thereto. Any person familiar with the technical field can easily think of various equivalents within the scope of the technology disclosed in the application. Modifications or replacements, these modifications or replacements shall be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (10)

1. A carbon dioxide incubator which characterized in that: the incubator comprises a controller (21), wherein the controller (21) is used for controlling the opening and closing of a first electromagnetic valve (3), a second electromagnetic valve (5) and a third electromagnetic valve (6) according to carbon dioxide concentration signals acquired by a first sensor (16), a second sensor (17) and a third sensor (23) in real time so as to adjust the concentration of carbon dioxide in the incubator; the air inlet of the incubator is communicated with a carbon dioxide air path, an air path and a balance air path, the balance air is air from which carbon dioxide is filtered, and the air source of the balance air path is a gas treatment device communicated with the air path; the gas treatment device comprises a washing container (7) and a drying container (8); the air input into the gas washing container from the air gas path is subjected to carbon dioxide removal treatment in the gas washing container, and then is introduced into the drying container to remove moisture to form balance gas; and the carbon dioxide gas circuit, the air gas circuit and the balance gas circuit are respectively provided with an electromagnetic valve which is used for controlling the flow of the gas circuit and is connected with the controller.

2. A carbon dioxide incubator according to claim 1 wherein: the carbon dioxide gas circuit comprises a first gas inlet pipeline (12), a first electromagnetic valve (3), a pressure reducing valve (2) and a carbon dioxide gas bottle (1) which are connected in sequence; when the first electromagnetic valve is conducted, the carbon dioxide gas bottle inputs high-pressure pure carbon dioxide gas to the incubator;

the air path comprises a second air inlet pipeline (13), a second electromagnetic valve (5) and an air pump (4) which are connected in sequence; when the second electromagnetic valve is conducted, the air pump inputs external air to the incubator;

the balance gas path comprises a third gas inlet pipeline (14), a third electromagnetic valve (6), a one-way valve (9) and a gas processing device which are connected in sequence; the one-way valve is positioned at the output end of the gas treatment device to prevent gas from flowing backwards; when the third electromagnetic valve is conducted, the air pump inputs external air to the air washing container, so that the air treatment device generates balance air and inputs the balance air to the incubator.

3. A carbon dioxide incubator according to claim 2 wherein: the incubator comprises a connector, an air inlet (11) and an air outlet (18); one port of the connector (10) is communicated with the air inlet, and the other ports of the connector are also respectively communicated with the first air inlet pipeline, the second air inlet pipeline and the third air inlet pipeline; the top of the incubator is provided with a fan (15) for mixing the gas in the incubator; a manual proportion adjusting valve for adjusting the output rate of the gas in the incubator is arranged at the gas outlet; the controller is connected with the touch display screen (22).

4. A carbon dioxide incubator according to claim 2 wherein: the controller is connected with a first sensor (16) and a second sensor (17) in the incubator to detect the concentration of carbon dioxide in the incubator in real time and judge the mixing uniformity of the carbon dioxide in the incubator, and is also connected with a third sensor (23) at the air inlet of the air pump to detect the concentration of the carbon dioxide of air input into the incubator by the air circuit in real time;

the controller controls the first electromagnetic valve, the second electromagnetic valve and the third electromagnetic valve according to the detection data of the first sensor, the second sensor and the third sensor so as to control the concentration of the carbon dioxide gas in the incubator.

5. A carbon dioxide incubator according to claim 2 wherein: a NaOH solution for absorbing carbon dioxide is stored in the gas washing container; the outlet of the air inlet pipe of the gas washing container is of a porous structure and is immersed in the NaOH solution; the drying container is filled with CaO crystals.

6. A method of controlling a carbon dioxide incubator with controlled concentration, using the incubator of claims 1-5, characterized in that: the control method includes the following contents;

method A, at the beginning, the controller is used to set the carbon dioxide concentration C required in the incubator ₁ (ii) a Secondly, at the beginning of each control period, the controller acquires the detection values of the first sensor and the second sensor, and the average value C of the carbon dioxide concentration of the two sensors is obtained ₂ As the current carbon dioxide gas concentration in the tank, the carbon dioxide concentration value C of the third sensor is obtained simultaneously ₃ (ii) a Then the controller compares C ₁ 、C ₂ And C ₃ Determining a corresponding control scheme to control the first electromagnetic valve, the second electromagnetic valve and the third electromagnetic valve;

method B, when setting value C ₁ Carbon dioxide concentration C of the outside air or higher ₃ At the moment, natural air or pure carbon dioxide is injected to improve the concentration of the carbon dioxide in the box; during the injection, when the set value C is ₁ Mean value of concentration C in comparison box ₂ When the difference value is higher than 100ppm, the concentration in the tank is quickly improved by controlling the first electromagnetic valve to inject pure carbon dioxide; otherwise, the second electromagnetic valve is opened to inject outside air, or the third electromagnetic valve is opened to inject balance gas, so that the concentration of carbon dioxide in the tank is increased or reduced and stabilized at a set value;

method C, when the set value C ₁ Carbon dioxide concentration C less than that of the outside air ₃ At this time, natural air is injected or no dioxygen is containedCarbonizing the air to reduce the concentration of carbon dioxide in the tank; during the injection process, when the concentration average value C in the tank is ₂ Ratio set value C ₁ When the difference value is higher than 100ppm, the concentration in the box is reduced more quickly by controlling the third electromagnetic valve to inject balance gas; if not, the carbon dioxide concentration in the box is increased or decreased by opening the first electromagnetic valve to inject the carbon dioxide or opening the second electromagnetic valve to inject the external air, so that the carbon dioxide concentration is stabilized at the set value.

7. The method for controlling a carbon dioxide incubator according to claim 6, wherein: after the controller determines the electromagnetic valve to be controlled, the controller sets a value C ₁ And the average concentration C ₂ Inputting the current signals into a Smith pre-estimation control module, and calculating the conduction time of the corresponding electromagnetic valve; the Smith pre-estimation control module is formed by introducing a Smith pre-estimation device at two ends of a traditional PI controller, and forming the Smith pre-estimation control module together with the PI controller, and is used for compensating an error formed by the delay of the conduction of input gas from the electromagnetic valve to the uniform mixing of the gas in the tank on the adjustment of the concentration of carbon dioxide so as to accelerate the adjustment speed; and finally, the controller controls the electromagnetic valve to act according to the conduction time, gas with different carbon dioxide concentrations is injected through the three gas inlet pipelines, the carbon dioxide concentration in the box is further adjusted, and then the controller waits for the next control period to arrive.

8. The method for controlling a carbon dioxide incubator according to claim 7, wherein:

the first electromagnetic valve, the second electromagnetic valve and the third electromagnetic valve are all on-off type electromagnetic valves.

9. The method for controlling a carbon dioxide incubator according to claim 7, wherein: when the pressure of the carbon dioxide in the carbon dioxide gas cylinder is still higher after the pressure of the carbon dioxide in the carbon dioxide gas cylinder is reduced by the pressure reducing valve, the pressure is continuously reduced by adopting the following method: when the first electromagnetic valve is controlled, the control period is divided into a plurality of time intervals according to the fixed conduction interval, the conduction time calculated by the Smith pre-estimation control module is converted into corresponding time intervals, so that the first electromagnetic valve is conducted for a fixed time length only in the time intervals, and carbon dioxide gas is output to the incubator in a small amount and multiple times to reduce the air pressure; the first solenoid valve will remain in the off state for a remaining off time other than the calculated on time.

10. The method for controlling a carbon dioxide incubator according to claim 9, wherein: the human-computer interaction interface of the controller comprises a touch display screen, when different carbon dioxide gas concentrations are needed in different periods, a set curve is input through the touch display screen, and the controller regulates and controls the first electromagnetic valve (3), the second electromagnetic valve (5) and the third electromagnetic valve (6) in real time according to the curve, so that the carbon dioxide concentration in the box changes according to the set curve.

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