PDMS microfluidic porous liquid membrane gas purification closed-loop control device

Abstract

The present application belongs to the air purification technical field, and particularly relates to a PDMS micro-fluidic porous liquid membrane gas purification closed-loop control device, which comprises a purifier body, a PDMS porous liquid membrane filter core is installed in the purifier body, and a purified gas outlet is arranged at the upper end of the purifier body; one end of the side of the PDMS porous liquid membrane filter core is connected with the inner end of a gas inlet pipeline, the outer end of the gas inlet pipeline serves as an inlet of the polluted gas flow, and the bottom end of the PDMS porous liquid membrane filter core is connected with a waste liquid pool; an air suction fan, a pneumatic proportional micro valve and a first pressure sensor are installed on the gas inlet pipeline; a cleaning pipeline with a second pressure sensor is installed at the upper end of the PDMS porous liquid membrane filter core, and a controller is connected with the pneumatic proportional micro valve, the first pressure sensor and the second pressure sensor respectively. The present application realizes the gas purification function of micro-fluids, has the advantages of diversified purification targets, low cost, low risk of secondary pollution, high controllability and small size, and meets the indoor and portable gas purification requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of air purification, and particularly relates to a PDMS micro-fluidic porous liquid membrane gas purification closed-loop control device. BACKGROUND

[0002] With the increasingly prominent problem of air pollution, according to incomplete statistics, more than 100 pollutants have attracted widespread attention, and air purification devices can effectively improve air quality and improve the living environment of human beings. Current air purification technologies include activated carbon adsorption, HEPA filter filtration, catalytic technology and negative ion purification technology, which mainly utilize the adsorption and filtration functions of solid materials or achieve purification purposes based on physical and chemical changes through external photoelectric effects.

[0003] The existing air purification devices have the following disadvantages: 1) the purification materials are prone to adsorption saturation, and need to be replaced or regenerated regularly, otherwise secondary pollution will occur, and the cost is high; 2) the purification target is relatively single, such as dust particle purifiers or formaldehyde purifiers; 3) the purification effect lacks active and precise control; and 4) the volume is large, which cannot meet the demand trend of miniaturization and integration. SUMMARY

[0004] The purpose of the application is to solve the problems of current air purification devices, such as easy saturation, secondary pollution risk, single purification target, poor controllability of purification effect and large volume, and provide a PDMS micro-fluidic porous liquid membrane gas purification closed-loop control device.

[0005] To achieve the above technical purposes and effects, the application is implemented by the following technical solutions:

[0006] A PDMS micro-fluidic porous liquid membrane gas purification closed-loop control device, comprising a purifier body, an air inlet pipeline, a PDMS porous liquid membrane filter core, a waste liquid pool, a cleaning pipeline, a first pressure sensor, a second pressure sensor and a controller.

[0007] The PDMS porous liquid membrane filter core is arranged close to the bottom of the inner cavity of the purifier body, and the upper end of the purifier body is provided with a purified gas outlet.

[0008] One end of the side of the PDMS porous liquid membrane filter core is connected with the inner end of the air inlet pipeline, the outer end of the air inlet pipeline serves as an inlet for the polluted gas flow, and the bottom end of the PDMS porous liquid membrane filter core is connected with the waste liquid pool.

[0009] An air guiding fan for providing air guiding force, a pneumatic proportional micro valve for adjusting the inlet gas flow pressure and a first pressure sensor for detecting the inlet gas flow pressure are installed on the air inlet pipeline.

[0010] The upper end of the PDMS porous liquid membrane filter core is provided with a cleaning pipeline capable of spraying functional filtering liquid or cleaning liquid into the pipeline, and the cleaning pipeline is provided with a second pressure sensor for detecting the liquid pressure of the pipeline.

[0011] The controller is connected with the pneumatic proportional micro valve, the first pressure sensor and the second pressure sensor respectively.

[0012] Further, in the PDMS microfluidic porous liquid membrane gas purification closed-loop control device, the PDMS porous liquid membrane filter core comprises a PDMS porous membrane located at the upper layer and a PDMS filter located at the lower layer, and the side surface of the PDMS porous membrane is uniformly provided with micropores capable of forming a liquid membrane by tension.

[0013] Further, in the PDMS microfluidic porous liquid membrane gas purification closed-loop control device, the thickness of the PDMS porous liquid membrane filter core is 0.2-0.5 mm, and the radius of the micropore is 0.05-0.2 mm.

[0014] Further, in the PDMS microfluidic porous liquid membrane gas purification closed-loop control device, the PDMS porous liquid membrane filter core is made of PDMS silica gel material as a whole, which has the advantages of corrosion resistance, stable physical and chemical properties, convenient manufacturing, low cost and rapid forming.

[0015] Further, in the PDMS microfluidic porous liquid membrane gas purification closed-loop control device, one end of the cleaning pipeline is provided with a nozzle, and the other end is connected with the liquid outlet pipeline of the filtering liquid storage tank and the cleaning liquid storage tank through a micropump, and a micro pressure regulating valve is installed on the liquid outlet pipeline of the cleaning pipeline, the filtering liquid storage tank and the cleaning liquid storage tank; the nozzle is arranged at the top of the inner cavity of the PDMS porous liquid membrane filter core, the filtering liquid storage tank stores filtering liquid for absorbing impurities in the contaminated gas stream, and the cleaning liquid storage tank stores cleaning liquid for cleaning the PDMS porous liquid membrane filter core.

[0016] Further, in the PDMS microfluidic porous liquid membrane gas purification closed-loop control device, a gas detection sensor is installed at the outlet of the purifier body, the controller is connected with the gas detection sensor, and the gas detection sensor is a dust concentration sensor for detecting the content of solid particles or a body concentration sensor for detecting the content of toxic gas components.

[0017] Further, in the PDMS microfluidic porous liquid membrane gas purification closed-loop control device, a demister for capturing small droplets carried in the gas stream is installed in the purifier body, and the demister is arranged below the outlet of the purified gas stream.

[0018] Further, in the PDMS micro-fluidic porous liquid membrane gas purification closed-loop control device, the demister is internally provided with a plurality of baffles, the baffles are in at least one of horizontal type, herringbone type and V-shaped type.

[0019] The present application has the following advantages:

[0020] 1. The porous liquid membrane filter core is made of PDMS (polydimethylsiloxane) silica gel material, which is corrosion-resistant, stable in physical and chemical properties, simple in manufacturing process and fast in forming.

[0021] 2. Compared with solid purification materials, the present application can select filter liquid with different functions according to the needs of users to realize multifunctional purification of solid pollutants (smoke dust, etc.) and harmful gas components (methane, etc.), and the liquid is easy to replace, low in cost and not easy to cause secondary pollution.

[0022] 3. The present application uses a micro valve as a control element to realize closed-loop control of gas purification through a controller, which is small in overall size and high in control precision, meeting the development trend of high precision and miniaturization of the purification device.

[0023] Of course, any product implementing the present application does not necessarily need to achieve all the above advantages at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0025] Figure 1 It is a structural schematic diagram of the whole application;

[0026] Figure 2 It is a structural schematic diagram of the PDMS porous liquid membrane filter core in the present application;

[0027] Figure 3 It is a cross-sectional view of the demister in the present application;

[0028] Figure 4 It is a schematic diagram of the system closed-loop control principle;

[0029] In the drawings, the reference numbers of the components are as follows:

[0030] 1. Purifier body; 2. Air inlet pipe; 2-1. Exhaust fan; 2-2. Pneumatic proportional micro-valve; 3. PDMS porous liquid membrane filter element; 3-1. PDMS porous membrane; 3-2. Micropores; 3-3. PDMS filter element; 4. Waste liquid tank; 5. Cleaning pipe; 5-1. Micro pump; 5-2. Filtrate storage tank; 5-3. Cleaning liquid storage tank; 6. First pressure sensor; 7. Miniature pressure regulating valve; 8. Gas detection sensor; 9. Controller; 10. Demister; 10-1. Baffle plate; 11. Second pressure sensor. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1-4 As shown, this embodiment provides a PDMS microfluidic porous liquid membrane gas purification closed-loop control device, including a purifier body 1, an air inlet pipe 2, a PDMS porous liquid membrane filter element 3, a waste liquid tank 4, a cleaning pipe 5, a first pressure sensor 6, a second pressure sensor 11, a micro pressure regulating valve 7, and a controller 9. The PDMS porous liquid membrane filter element 3 is installed inside the purifier body 1, located near the bottom of the inner cavity of the purifier body 1. The upper end of the purifier body 1 has a purified airflow outlet. One side end of the PDMS porous liquid membrane filter element 3 is connected to the inner end of the air inlet pipe 2, and the outer end of the air inlet pipe 2 serves as the inlet for the polluted airflow. The bottom end of the PDMS porous liquid membrane filter element 3 is connected to the waste liquid tank 4.

[0033] In this embodiment, the intake pipe 2 is equipped with an exhaust fan 2-1 for providing induced draft, a pneumatic proportional micro-valve 2-2 for adjusting the inlet air pressure, and a first pressure sensor 6 for detecting the inlet air pressure; the upper end of the PDMS porous liquid membrane filter element 3 is equipped with a cleaning pipe 5 that can spray functional filter liquid or cleaning liquid into it, and the cleaning pipe 5 is equipped with a second pressure sensor 11 for detecting the liquid pressure in the pipe.

[0034] In the embodiment, the PDMS porous liquid membrane filter core 3 includes a PDMS porous membrane 3-1 at the upper layer and a PDMS filter hopper 3-3 at the lower layer, and the PDMS porous membrane 3-1 is uniformly provided with micropores 3-2 capable of forming a liquid membrane by tension. The thickness of the PDMS porous liquid membrane filter core 3 is 0.2-0.5 mm, and the radius of the micropore 3-2 is 0.05-0.2 mm. The micropore 3-2 is internally filled with a functional filtering liquid by the action of liquid surface tension, and the cross section of the micropore 3-2 is circular or other shapes. The PDMS porous liquid membrane filter core 3 is integrally made of PDMS silica gel material, is corrosion-resistant, is stable in physical and chemical properties, is convenient to make, is low in cost, and can be quickly formed.

[0035] In the embodiment, one end of the cleaning pipeline 5 is provided with a nozzle 5-4, and the other end is connected to the liquid outlet pipelines of the filtering liquid storage tank 5-2 and the cleaning liquid storage tank 5-3 through a micropump 5-1, and a miniature pressure regulating valve 7 is installed on the liquid outlet pipelines of the cleaning pipeline 5, the filtering liquid storage tank 5-2 and the cleaning liquid storage tank 5-3; the nozzle 5-4 is arranged at the top of the inner cavity of the PDMS porous liquid membrane filter core 3, the filtering liquid storage tank 5-2 stores a filtering liquid for absorbing impurities in the contaminated gas stream, and the cleaning liquid storage tank 5-3 stores a cleaning liquid for cleaning the PDMS porous liquid membrane filter core 3. The micropump 5-1 can be a mechanical micropump (such as a piezoelectric type, a pneumatic type, etc.) or a non-mechanical micropump (such as an electro-osmotic type, an electro-wetting type, etc.). The filtering liquid can be water, oil, ethanol or other chemical solvents.

[0036] In the embodiment, the purifier body 1 is provided with a gas detection sensor 8 at the outlet of the purified gas stream, the controller 9 is connected to the gas detection sensor 8, and the gas detection sensor 8 is a dust concentration sensor for detecting the content of solid particles or a body concentration sensor for detecting the content of toxic gas (such as methane, carbon monoxide, etc.).

[0037] In the embodiment, the inside of the purifier body 1 is provided with a demister 10 for capturing small liquid droplets carried in the gas stream, and the demister 10 is arranged below the outlet of the purified gas stream. The inside of the demister 10 is provided with a plurality of baffle plates 10-1, the shape of the baffle plate 10-1 is a broken line type or a streamline type, and the arrangement form of the baffle plate 10-1 is at least one of a horizontal type, an inverted V type and a V type.

[0038] In this embodiment, the controller 9 is connected with the pneumatic proportional micro valve 2-2, the first pressure sensor 6, the second pressure sensor 11, the micro pressure regulating valve 7 and the gas detection sensor 8 respectively. The controller 9 is provided with a control module. The pressure signal of the polluted gas stream at the inlet of the PDMS porous liquid membrane filter core 3 and the concentration signal of the pollutants in the purified gas stream at the outlet are collected by the first pressure sensor 6 and the gas detection sensor 8. The concentration information of the pollutants in the purified gas stream is compared with the set value. If the set threshold is exceeded, the control module in the controller 9 sends a command to adjust the valve opening of the pneumatic proportional micro valve 2-2 at the gas stream inlet, so as to realize closed-loop control of the purification effect.

[0039] In this embodiment, the water inlet pipeline 2 and the cleaning pipeline 5 are both made of polytetrafluoroethylene pipe with light weight, which can be conveniently connected with the high-elasticity PDMS material without leakage, and is convenient for cleaning or replacing the PDMS porous liquid membrane filter core 3.

[0040] The working principle of this embodiment is as follows:

[0041] The PDMS porous liquid membrane filter core 3 and the pressure-driven closed-loop controller 9 are used to realize purification of the polluted gas stream. The microfluidic surface tension characteristics are used to fill the filter liquid in the micropores 3-1 of the PDMS porous liquid membrane filter core 3, so as to form a stable liquid membrane. The polluted gas stream enters the PDMS porous liquid membrane filter core 3 from the gas inlet pipeline 2, and the gas-liquid-solid multiphase flow in the PDMS micropores 3-1 interacts. Under the action of pressure, the gas passes through the liquid membrane, and the pollutants in the gas are captured by the filter liquid. The controller 9 collects the pressure information of the polluted gas stream at the inlet of the PDMS porous liquid membrane filter core 3 and the concentration information of the pollutants in the purified gas stream at the outlet through the first pressure sensor 6 and the gas detection sensor 8. The concentration information of the pollutants in the purified gas stream is compared with the set value. If the set threshold is exceeded, the control module in the controller 9 sends a control command to change the valve opening of the pneumatic proportional micro valve 2-2, so as to adjust the gas pressure in the PDMS porous liquid membrane filter core 3, improve the purification efficiency at the outlet, and realize closed-loop control of the liquid membrane purification effect. During the gas purification process, part of the filter liquid will be carried away by the gas stream. Therefore, a demister 10 is arranged at the outlet of the gas stream for capturing small liquid droplets carried by the gas stream.

[0042] At the same time, the cleaning pipeline 5 supplies the filter liquid to the micropores 3-1 through the micropump 5-1 regularly, and transports the cleaning liquid regularly to realize the liquid membrane cleaning function.

[0043] The PDMS microfluidic porous liquid membrane gas purification closed-loop control device disclosed in this embodiment can not only be applied to indoor air purification, but also be integrated into various respiratory masks to realize portable air purification function.

[0044] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to provide the best illustration of the application and its practical application to those skilled in the art and to enable those skilled in the art to best utilize the application. The application is only limited by the claims as well as their full scope and equivalents.

Claims

1. A PDMS microfluidic multi-well liquid membrane gas purification closed-loop control device, characterized in that, The purifier body (1), the air inlet pipeline (2), the PDMS porous liquid membrane filter core (3), the waste liquid pool (4), the cleaning pipeline (5), the first pressure sensor (6), the second pressure sensor (11) and the controller (9) are included. The PDMS porous liquid membrane filter core (3) is installed in the purifier body (1), and the PDMS porous liquid membrane filter core (3) includes the PDMS porous membrane (3-1) in the upper layer and the PDMS filter hopper (3-3) in the lower layer, and the side surface of the PDMS porous membrane (3-1) is uniformly distributed with the micropore (3-2) capable of forming a liquid membrane by tension; the thickness of the PDMS porous liquid membrane filter core (3) is 0.2-0.5 mm; the radius of the micropore (3-2) is 0.05-0.2 mm; the PDMS porous liquid membrane filter core (3) is integrally made of PDMS silica gel material; the PDMS porous liquid membrane filter core (3) is arranged close to the inner cavity bottom of the purifier body (1), and the upper end of the purifier body (1) is provided with a purified gas flow outlet. One end of the side of the PDMS porous liquid membrane filter core (3) is connected with the inner end of the air inlet pipeline (2), the outer end of the air inlet pipeline (2) serves as an inlet for the contaminated gas flow, and the bottom end of the PDMS porous liquid membrane filter core (3) is connected with the waste liquid pool (4). An air induction fan (2-1) for providing air induction force, a pneumatic proportional micro valve (2-2) for adjusting the inlet gas flow pressure and a first pressure sensor (6) for detecting the inlet gas flow pressure are installed on the air inlet pipeline (2). The upper end of the PDMS porous liquid membrane filter core (3) is provided with a cleaning pipeline (5) capable of spraying functional filtering liquid or cleaning liquid into the PDMS porous liquid membrane filter core (3), and the cleaning pipeline (5) is provided with a second pressure sensor (11) for detecting the liquid pressure of the pipeline. The controller (9) is connected with the pneumatic proportional micro valve (2-2), the first pressure sensor (6) and the second pressure sensor (11) respectively.

2. The PDMS microfluidic multi-well liquid membrane gas purification closed loop control device according to claim 1, wherein, One end of the cleaning pipeline (5) is provided with a nozzle (5-4), and the other end is connected with the liquid outlet pipelines of the filtering liquid storage tank (5-2) and the cleaning liquid storage tank (5-3) through a micro pump (5-1), and a micro pressure regulating valve (7) is installed on the cleaning pipeline (5), the liquid outlet pipelines of the filtering liquid storage tank (5-2) and the cleaning liquid storage tank (5-3); the nozzle (5-4) is arranged at the inner cavity top of the PDMS porous liquid membrane filter core (3), the filtering liquid storage tank (5-2) stores filtering liquid for absorbing impurities in the contaminated gas flow, and the cleaning liquid storage tank (5-3) stores cleaning liquid for cleaning the PDMS porous liquid membrane filter core (3).

3. The PDMS microfluidic multi-well liquid membrane gas purification closed loop control device according to claim 2, wherein, The purifier body (1) is provided with a gas detection sensor (8) at the purified gas flow outlet, the controller (9) is connected with the gas detection sensor (8), and the gas detection sensor (8) is a dust concentration sensor for detecting the solid particle content or a body concentration sensor for detecting the toxic gas component content.

4. The PDMS microfluidic multi-well liquid membrane gas purification closed loop control device according to claim 3, wherein, The inside of the purifier body (1) is internally provided with a demister (10) for capturing small liquid droplets carried in the gas flow, and the demister (10) is arranged below the outlet of the purified gas flow.

5. The PDMS microfluidic multi-well liquid membrane gas purification closed loop control device according to claim 4, wherein, The inside of the demister (10) is provided with a plurality of baffle plates (10-1), the shape of the baffle plates (10-1) is a broken line type or a streamline type, and the arrangement form of the baffle plates (10-1) is at least one of a horizontal type, a herringbone type and a V-shaped type.

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