Filtering device of micro sample injector

Abstract

The invention discloses a filter device of a micro sample injector. The filter device of the micro sample injector comprises a cover plate, a runner layer, a valve membrane layer, a base and a filter screen, the cover plate, the runner layer, the valve membrane layer and the base are sequentially arranged from top to bottom; two lower positioning grooves are formed in the base, two upper positioning grooves are formed in the positions, corresponding to the lower positioning grooves, of the bottom of the runner layer, the shapes of the lower positioning grooves and the upper positioning grooves are matched with the shape of the filter screen, and the filter screen is placed in the lower positioning grooves. And the valve membrane layer is arranged above the filter screen in a covering manner. The upper positioning groove and the lower positioning groove are formed in the runner layer and the base correspondingly, the filter screen is placed in the lower positioning groove, and through cooperation of the upper positioning groove and the lower positioning groove, no extra clamping structure or complex post-processing steps are needed; the technological process is simplified, and the limiting effect on the filter screen is effectively achieved.

Description

Technical Field

[0001] This invention relates to the field of microsampler technology, and more particularly to a filtering device for a microsampler. Background Technology

[0002] Micro-GC is an analytical instrument that achieves miniaturization, integration, and portability by utilizing microelectromechanical systems (MEMS) technology, building upon traditional gas chromatography. Its core objective is to reduce volume, weight, and power consumption by one to two orders of magnitude while maintaining high separation efficiency, meeting the needs of rapid on-site detection (such as environmental monitoring, chemical safety, medical diagnostics, and space exploration). The injector, as the "entry point" of Micro-GC, directly determines analytical accuracy and reliability, making it one of the most challenging modules in the miniaturization process.

[0003] Microsamplers can precisely introduce minute amounts of sample (nanoli to microliter), enabling instantaneous injection of gaseous / volatile liquid samples, avoiding sample diffusion, maintaining "plug flow" injection, and preventing residue and cross-contamination. To achieve miniaturization and convenience, the sampler size must be kept small. Filters need to be placed at the sample gas inlet and the carrier gas inlet of the sampler to prevent large impurities from entering the gas chromatography system, contaminating the entire device, and affecting the detection efficiency and lifespan of the gas chromatography system.

[0004] However, existing micro gas chromatographs are difficult to integrate into a complete process. Conventional micro-injectors use a method of clamping the filter in the middle by bonding a double-layer polyimide film. This approach typically employs a process path of cutting first and then bonding. The filter integration method involves clamping and fixing the double-layer polyimide (PI) film onto the individual chip unit after cutting. This method has several drawbacks: First, the operating objects are tiny, independent chips, resulting in extremely limited operating space and a cumbersome process. Second, multiple individual alignments are required during the stacking and bonding process, making it difficult to guarantee alignment accuracy and resulting in low production efficiency. Third, in high-temperature environments, the thermal motion between polymer film molecules can cause the filter to shift, reducing the lifespan of the injector with repeated use. Furthermore, in portable gas chromatography systems, frequent removal and placement are necessary. Existing film bonding lacks rigid fixation, making the filter prone to displacement or even damage to the film bonding surface when the injector is subjected to vibration and impact.

[0005] Therefore, there is an urgent need for a new filtration device for miniature samplers. Summary of the Invention

[0006] In view of the above problems, the present invention is proposed to provide a filtration device for a micro-sampler that overcomes or at least partially solves the above problems.

[0007] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0008] This invention provides a filtration device for a micro-injector, comprising: a cover plate, a flow channel layer, a valve membrane layer, a base, and a filter screen; the cover plate, flow channel layer, valve membrane layer, and base are arranged sequentially from top to bottom; the base is provided with two lower positioning grooves, and the bottom of the flow channel layer is provided with two upper positioning grooves corresponding to the positions of the lower positioning grooves; the shapes of the lower positioning grooves and the upper positioning grooves match the shape of the filter screen; the filter screen is placed in the lower positioning grooves, and the valve membrane layer covers the top of the filter screen.

[0009] In some embodiments of the present invention, the cover plate is made of BF33 glass, and the base is made of BF33 glass or silicon.

[0010] In some embodiments of the present invention, the channel layer is made of silicon, the upper layer of the channel layer is etched with channels, and the cover plate is disposed over the channels and bonded to the channel layer to form a channel cavity.

[0011] In some embodiments of the present invention, the valve membrane layer is made of polyimide membrane, and the flow channel layer and the base are bonded based on the hot-press bonding process performed on the valve membrane layer; the thickness of the polyimide membrane is 12.5~100μm.

[0012] In some embodiments of the present invention, the filter screen is a mesh structure with filter holes, the mesh count of the filter screen is 1000-3000, and the material of the filter screen is 316L stainless steel that has undergone passivation treatment.

[0013] In some embodiments of the present invention, the lower positioning groove, the upper positioning groove, and the filter screen are circular in shape, and the diameters of the lower positioning groove, the upper positioning groove, and the filter screen are in the order of upper positioning groove > lower positioning groove > filter screen; the diameter of the upper positioning groove is 2.5 mm, and the depth of the upper positioning groove is 0.05~0.2 mm; the diameter of the lower positioning groove is 2.4 mm, and the depth of the lower positioning groove is 0.05~0.2 mm; the diameter of the filter screen is 2.4 mm.

[0014] In some embodiments of the present invention, the cover plate is bonded to the flow channel layer to form a flow channel cavity. The flow channel layer is provided with a sample air inlet and two upper vent holes. The two upper vent holes are respectively located in the upper positioning groove, and the sample air inlet and the two upper vent holes are all connected to the flow channel cavity. The diameter of the upper vent holes is 0.6~1.0mm, and the depth of the upper vent holes is 0.05~0.2mm.

[0015] In some embodiments of the present invention, the valve diaphragm layer is provided with thin film through holes corresponding to the positions of the upper vent holes; the lower positioning groove is provided with lower vent holes corresponding to the positions of the upper vent holes; the diameter of the lower vent holes is 0.6~1.0 mm, and the depth of the lower vent holes is 0.05~0.2 mm.

[0016] In some embodiments of the present invention, an air inlet hole is provided on the cover plate at a position corresponding to the sample air inlet, and the air inlet hole is in communication with the sample air inlet.

[0017] In some embodiments of the present invention, a second positioning hole is provided on the flow channel layer, and a first positioning hole, a third positioning hole, and a fourth positioning hole are respectively provided on the cover plate, the valve diaphragm layer, and the base corresponding to the position of the second positioning hole.

[0018] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The microsampler filtration device described in this embodiment of the invention features an upper positioning groove and a lower positioning groove on the flow channel layer and the base, respectively. The filter screen is placed in the lower positioning groove. Through the cooperation of the upper and lower positioning grooves, the filter screen is effectively positioned without any additional clamping structures or complex post-processing steps. Compared with the existing double-layer clamping filter screen solution, the flow channel layer and base of this invention only require one bonding to achieve wafer-level bonding through a single valve membrane layer. That is, before wafer dicing, the corresponding upper and lower positioning grooves can be quickly processed on the upper and lower wafers through an etching process. The placement of the filter screen is also performed on the overall wafer structure. The filter screen placement, alignment, and fixing are integrated into a one-step bonding process of a 6-inch wafer, which greatly simplifies the operation process. Not only is the alignment of the filter screen accurate, but it also facilitates batch placement of filter screens, greatly improving production efficiency and integration accuracy.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an exploded structural diagram of a filtration device for a micro-sampler provided in an embodiment of the present invention; Figure 2 This is a diagram showing the connection of the filter screen; Figure 3 This is a side sectional view of the filter screen connection.

[0022] Explanation of reference numerals in the attached figures: 1. Cover plate; 2. Flow channel layer; 3. Valve membrane layer; 4. Base; 5. Filter screen; 11. Air inlet; 12. First positioning hole; 20. Upper positioning groove; 21. Sample air inlet; 22. Second positioning hole; 23. Upper vent; 31. Third positioning hole; 32. Membrane through hole; 41. Fourth positioning hole; 42. Lower positioning groove; 43. Lower vent. Detailed Implementation

[0023] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0024] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0025] In the context of this disclosure, when a layer / component is referred to as being "above" another layer / component, that layer / component may be directly above the other layer / component, or there may be an intermediate layer / component between them. Additionally, if a layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component may be "below" the other layer / component. In the context of this disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0026] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0027] Figure 1 This is an exploded structural diagram of a filtration device for a micro-sampler provided in an embodiment of the present invention. Figure 2 This is a connection diagram for filter 5. Figure 3 This is a sectional view of the connection side of filter 5, as shown below. Figure 1-3 As shown, the filtration device of this micro-sampler includes: a cover plate 1, a flow channel layer 2, a valve membrane layer 3, a base 4, and a filter screen 5; the cover plate 1, the flow channel layer 2, the valve membrane layer 3, and the base 4 are arranged sequentially from top to bottom; the base 4 is provided with two lower positioning grooves 42, and the bottom of the flow channel layer 2 is provided with two upper positioning grooves 20 corresponding to the positions of the lower positioning grooves 42. The shapes of the lower positioning grooves 42 and the upper positioning grooves 20 match the shape of the filter screen 5. The filter screen 5 is placed in the lower positioning grooves 42, and the valve membrane layer 3 covers the filter screen 5; thus, the filter screen 5 is limited by the cooperation of the lower positioning grooves 42 and the upper positioning grooves 20.

[0028] In this embodiment of the invention, the cover plate 1 is made of BF33 glass and is used to form an encapsulation structure with the flow channel layer 2 and generate a flow channel cavity.

[0029] The flow channel layer 2 is made of silicon, and the upper layer of the flow channel layer 2 is etched with flow channels. The cover plate 1 is placed over the flow channels and bonded to the flow channel layer 2 to form a flow channel cavity.

[0030] The valve membrane layer 3 is made of polyimide film, which has good insulation properties. The flow channel layer 2 and the base 4 are bonded to each other by hot-press bonding based on the valve membrane layer 3. The hot-press bonding process is performed at a temperature of 300~360°C and a pressure of 0.1~0.5MPa, preferably 320°C and 0.18MPa. The thickness of the polyimide film is 12.5~100μm.

[0031] The base 4 is made of BF33 glass or silicon.

[0032] The filter screen 5 is a mesh structure with filter holes. The mesh size of the filter screen 5 is 1000-3000, preferably 2000. The filter screen 5 is made of 316L stainless steel that has undergone passivation treatment.

[0033] In this embodiment of the invention, the lower positioning groove 42, the upper positioning groove 20, and the filter screen 5 are circular in shape. The diameters of the lower positioning groove 42, the upper positioning groove 20, and the filter screen 5 are in the following order: upper positioning groove 20 > lower positioning groove 42 > filter screen 5. The diameter of the upper positioning groove is 2.2~4.2 mm, and the depth of the upper positioning groove is 0.05~0.2 mm; the diameter of the lower positioning groove is 2.2~4.2 mm, and the depth of the lower positioning groove is 0.05~0.2 mm; the diameter of the filter screen is 2~4 mm. Preferably, the diameter of the upper positioning groove 20 is 2.5 mm, and the depth of the upper positioning groove 20 is 0.1 mm; the diameter of the lower positioning groove 42 is 2.4 mm, and the depth of the lower positioning groove 42 is 0.1 mm; the diameter of the filter screen 5 is 2.3 mm, and the thickness of the filter screen is 0.1 mm. mm; the size of the lower positioning groove 42 is larger than the size of the filter screen 5, which can provide a certain clearance space for the placement of the filter screen 5. At the same time, the size of the upper positioning groove 20 is larger than the size of the lower positioning groove 42, which can make the valve membrane layer 3 form a bending space at the junction of the upper positioning groove 20 and the upper edge of the filter screen 5, further improving the limiting effect on the filter screen 5.

[0034] In other embodiments of the present invention, the diameters of the lower positioning groove 42, the upper positioning groove 20, and the filter screen 5 can be reversed. In this case, the filter screen 5 is placed in the upper positioning groove 20, that is, the valve membrane layer 3 is located below the filter screen 5.

[0035] The cover plate 1 is bonded to the flow channel layer 2 to form a flow channel cavity. The flow channel layer 2 is provided with a sample air inlet 21 and two upper vent holes 23. The two upper vent holes 23 are respectively located in the upper positioning groove 20, and the sample air inlet 21 and the two upper vent holes 23 are all connected to the flow channel cavity. The diameter of the upper vent holes is 0.6~1.0 mm, and the depth of the upper vent holes is 0.05~0.2 mm.

[0036] The valve diaphragm layer 3 has thin film through holes 32 at the positions corresponding to the upper vent 23, and the depth of the thin film through holes 32 matches the thickness of the valve diaphragm layer 3.

[0037] The lower positioning groove 42 is provided with a lower vent hole 43 corresponding to the position of the upper vent hole 23; the diameter of the lower vent hole is 0.6~1.0 mm and the depth of the lower vent hole is 0.05~0.2 mm.

[0038] An air inlet 11 is provided on the cover plate 1 at the position corresponding to the sample air inlet 21, and the air inlet 11 is connected to the sample air inlet 21.

[0039] In this embodiment of the invention, the two upper vents 23 serve as the sample outlet and the carrier gas inlet, respectively. The sample gas is introduced into the sample inlet 21 through the inlet 11 and enters the flow channel cavity. The carrier gas is introduced into the flow channel cavity through the lower vent 43, the membrane through-hole 32 and the carrier gas inlet, and is discharged together with the sample gas through the sample outlet, another membrane through-hole 32 and another lower vent 43.

[0040] In this embodiment of the invention, a second positioning hole 22 is provided on the flow channel layer 2. A first positioning hole 12, a third positioning hole 31, and a fourth positioning hole 41 are respectively provided on the cover plate 1, the valve membrane layer 3, and the base 4 at the positions corresponding to the second positioning hole 22. The first positioning hole 12, the second positioning hole 22, the third positioning hole 31, and the fourth positioning hole 41 can be connected in series by a structure such as a pin, so as to provide a positioning function when installing and fixing the cover plate 1, the flow channel layer 2, the valve membrane layer 3, and the base 4 at each level.

[0041] The filtration device of the micro-sampler described in this embodiment of the invention has the following advantages compared with the prior art: 1. The present invention provides an upper positioning groove 20 and a lower positioning groove 42 on the flow channel layer 2 and the base 4 respectively, and places the filter screen 5 in the lower positioning groove 42. Through the cooperation of the upper positioning groove 20 and the lower positioning groove 42, without any additional clamping structure or complex post-processing steps, the limiting effect of the filter screen 5 is effectively achieved. In particular, during long-term use, the displacement problem of the filter screen 5 caused by the thermal shrinkage of the valve membrane layer 3 is avoided. 2. The diameters of the lower positioning groove 42, the upper positioning groove 20, and the filter screen 5 are in the order of upper positioning groove 20 > lower positioning groove 42 > filter screen 5. This not only provides a certain clearance space for the placement of the filter screen 5, but also allows the valve membrane layer 3 to form a bending space at the junction of the upper positioning groove 20 and the upper edge of the filter screen 5, thereby constraining the axial direction of the filter screen 5 and further improving the limiting effect on the filter screen 5. 3. Compared to existing double-layer clamping filter solutions, the flow channel layer and base of this invention can achieve wafer-level bonding with only one bonding through a single valve membrane layer. That is, before wafer dicing, the corresponding upper and lower positioning grooves can be quickly processed on the upper and lower wafers through etching. The placement of the filter is also carried out on the overall wafer structure. The multiple steps of filter placement, alignment and fixation are integrated into a one-step bonding process of 6-inch wafers, which greatly simplifies the operation process. Not only is the alignment of the filter accurate, but it is also easy to place the filter in batches, which greatly improves production efficiency and integration accuracy.

[0042] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0043] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of the invention above. Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and it should be noted that the above embodiments are illustrative of the invention and not restrictive, and that alternative embodiments can be devised by those skilled in the art without departing from its scope.

Claims

1. A filtration device for a miniature sample injector, characterized in that, The filtration device of the micro-injector includes: a cover plate, a flow channel layer, a valve membrane layer, a base, and a filter screen; the cover plate, the flow channel layer, the valve membrane layer, and the base are arranged sequentially from top to bottom; the base is provided with two lower positioning grooves, and the bottom of the flow channel layer is provided with two upper positioning grooves corresponding to the positions of the lower positioning grooves; the shapes of the lower positioning grooves and the upper positioning grooves match the shape of the filter screen; the filter screen is placed in the lower positioning grooves, and the valve membrane layer covers the top of the filter screen.

2. The filtration device for the microsampler according to claim 1, characterized in that: The cover plate is made of BF33 glass, and the base is made of BF33 glass or silicon.

3. The filtration device for the microsampler according to claim 2, characterized in that: The flow channel layer is made of silicon, and the upper layer of the flow channel layer is etched with flow channels. The cover plate is placed over the flow channels and bonded to the flow channel layer to form a flow channel cavity.

4. The filtration device for the microsampler according to claim 3, characterized in that: The valve membrane layer is made of polyimide membrane, and the flow channel layer and the base are bonded by hot pressing based on the valve membrane layer; the thickness of the polyimide membrane is 12.5~100μm.

5. The filtration device for the microsampler according to claim 4, characterized in that: The filter screen has a mesh structure with filter holes, the mesh size of the filter screen is 1000-3000, and the material of the filter screen is 316L stainless steel that has undergone passivation treatment.

6. The filtration device for the microsampler according to claim 1, characterized in that: The lower positioning groove, upper positioning groove, and filter screen are circular in shape. The diameters of the lower positioning groove, upper positioning groove, and filter screen are in the following order: upper positioning groove > lower positioning groove > filter screen. The diameter of the upper positioning groove is 2.2~4.2mm, and the depth of the upper positioning groove is 0.05~0.2mm. The diameter of the lower positioning groove is 2.2~4.2mm, and the depth of the lower positioning groove is 0.05~0.2mm. The diameter of the filter screen is 2~4mm.

7. The filtration device for the microsampler according to claim 3, characterized in that: The cover plate is bonded to the flow channel layer to form a flow channel cavity. The flow channel layer is provided with a sample air inlet and two upper vent holes. The two upper vent holes are respectively located in the upper positioning groove, and the sample air inlet and the two upper vent holes are all connected to the flow channel cavity. The diameter of the upper vent holes is 0.6~1.0 mm, and the depth of the upper vent holes is 0.05~0.2 mm.

8. The filtration device for the microsampler according to claim 7, characterized in that: The valve diaphragm layer has thin film through holes at the positions corresponding to the upper vent holes; the lower positioning groove has lower vent holes at the positions corresponding to the upper vent holes; the diameter of the lower vent holes is 0.6~1.0 mm, and the depth of the lower vent holes is 0.05~0.2 mm.

9. The filtration device for the microsampler according to claim 7, characterized in that: An air inlet is provided on the cover plate at the position corresponding to the sample air inlet, and the air inlet is connected to the sample air inlet.

10. The filtration device for the microsampler according to claim 1, characterized in that: A second positioning hole is provided on the flow channel layer, and a first positioning hole, a third positioning hole, and a fourth positioning hole are respectively provided on the cover plate, the valve diaphragm layer, and the base corresponding to the position of the second positioning hole.

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