CN220834964U - Needle filter - Google Patents

Abstract

The utility model relates to a needle filter, which comprises an upper shell, a lower shell, a filtering membrane layer and a gasket, wherein the upper shell is provided with a liquid inlet channel, the lower shell is in sealing connection with the upper shell, and the lower shell is provided with a liquid outlet channel; the filtering membrane layer is arranged between the upper shell and the lower shell; a gasket is disposed downstream of the filter membrane, the gasket at least partially overlapping an outer periphery of the filter membrane layer. Compared with the prior art, the gasket is arranged on the downstream side of the filtering membrane layer, so that a buffer cavity is formed between the filtering membrane layer and the lower shell, and permeate can enter the diversion surface more quickly, and the discharge efficiency of the permeate is improved.

Description

Needle filter

Technical Field

The utility model relates to the technical field of filtration, in particular to a needle filter.

Background

The membrane separation technology is a technology for realizing selective permeation of substances with different sizes in materials under the action of pore structures in a filtering membrane layer by means of pressure difference at two sides of the filtering membrane layer. According to different sizes of pore structures in the filtering membrane layer, the method can be divided into microfiltration, ultrafiltration and nanofiltration, and finally the purposes of separation, concentration, purification and refining are realized. Because the membrane separation technology has no phase change in the separation process, the working environment is mild, the equipment requirement is simple, the operation flow is simple and convenient, and the membrane separation technology is widely applied to the fields of biological pharmacy and life science.

The needle filter using the membrane separation technology is widely applied to small-volume sample filtration in a laboratory due to the simple and reasonable structure, low cost, convenience and rapidness. For example, CN103432794B provides a needle filter, which comprises an upper cover, a lower cover and a filtering membrane layer arranged between the upper cover and the lower cover, wherein the inner surfaces of the upper cover and the lower cover are provided with arc protrusions, arc grooves and radial grooves, so that a diversion surface is formed at the upstream and downstream of the filtering membrane layer, and the smooth filtering of materials in the needle filter is ensured. But in the use, the material can constantly produce the impact to filtration membrane layer to lead to filtration membrane layer and the inseparable laminating of lower casing, needle filter goes out liquid and is blocked, especially when impurity content in the filtration material is higher, goes out liquid blocking condition more serious. In addition, when the mechanical strength of the filter membrane layer is low, the risk of breakage increases due to deformation of the filter membrane layer caused by the embedding of the guide surface.

Disclosure of utility model

The utility model aims to provide a needle filter so as to reduce liquid outlet resistance and damage risk of a filter membrane and ensure smooth liquid outlet in the filtering process.

In order to achieve the above object, the following technical scheme is provided:

A needle filter comprising:

the upper shell is provided with a liquid inlet channel and an exhaust channel;

the lower shell is in sealing connection with the upper shell and is provided with a liquid outlet channel and a flow guide surface;

the filtering membrane layer is arranged between the upper shell and the lower shell;

And a gasket provided on the downstream side of the filter membrane layer, the gasket being at least partially overlapped with the filter membrane layer so that a buffer chamber is formed between the filter membrane layer and the lower case.

The buffer cavity is a cavity formed by surrounding a gasket between the filtering membrane layer and the lower shell, and can effectively prevent direct contact between the filtering membrane layer and the lower shell, so that the discharge efficiency of the penetrating fluid is improved.

As a preferable scheme of the utility model, the gasket is made of an elastic material, the elastic modulus of the gasket is 2.5-18.5 MPa, and the hardness of the gasket is 40-70A.

The elastic modulus of the gasket is set to be 2.5-18.5 MPa, so that a buffer effect can be provided for the filtering membrane layer when materials impact the filtering membrane layer in the filtering process, and irreversible deformation of the filtering membrane caused by excessive impact of the materials is avoided to influence the filtering performance of the filtering membrane; the elastic modulus is less than 2.5MPa, and the gasket can generate larger deformation in the filtering process, so that the filtering membrane layer is embedded into the guide surface to be damaged; when the elastic modulus is more than 18.5MPa, the deformation of the gasket under the action of the fixing area is too small, so that the sealing effect of the gasket is poor.

The hardness of the gasket is set to be 40-70A, and the gasket has a certain degree of deformability while supporting the filtering membrane layer, so that the filtering membrane layer can be extruded and sealed under the action of the fixed area; the hardness is less than 40A, the hardness of the gasket is insufficient, and the buffer cavity is easy to collapse in the filter forming process and the use process; the hardness is greater than 70A, and in the filter forming process, the gasket is extruded with the filtering membrane layer, and the gasket is easy to damage the filtering membrane layer due to the excessive hardness.

As a preferable scheme of the utility model, the tensile strength of the gasket is 3.2-10.5 MPa, and the elongation at break is 500-800%.

The gasket is extruded by the first fixing area and the second fixing area in the filter forming process, and a buffer cavity is formed while protecting the filtering membrane layer. The tensile strength of the gasket is set to be 3.2-10.5 MPa, and the gasket can deform to a certain extent in the extrusion process, so that the gasket is matched with the groove of the second fixing area to form additional fixing and sealing effects; when the tensile strength is less than 3.2MPa, the gasket is easy to damage in the extrusion process; the tensile strength is more than 10.5MPa, the gasket basically does not deform, the filtering membrane layer deforms after being extruded, and the damage is caused

As a preferable scheme of the utility model, the thickness of the gasket is 150-380 mu m.

The thickness of the gasket is set to be 150-380 mu m, so that the buffer cavity can effectively provide buffer volume for the permeate liquid, and meanwhile, the influence on the stability of the permeate liquid caused by the fact that the permeate liquid impacts the guide surface due to the oversized buffer cavity is avoided; the thickness is less than 150 mu m, the gasket is not enough to support the filtering membrane layer, and in the filtering process, the filtering membrane layer is easily embedded into the flow guiding surface at the center position far away from the gasket to be damaged; the thickness is greater than 380 mu m, the buffer cavity volume is overlarge, the dead volume of the filter is overlarge, the waste of materials is caused, and the too thick gasket is easy to deform unevenly in the forming process, so that the integral stability of the filter is damaged.

As a preferable scheme of the utility model, the gasket is of an annular structure, and the radial width of the gasket accounts for 10% -30% of the diameter of the filtering membrane layer.

The radial width of the gasket accounts for 10% -30% of the diameter of the filtering membrane layer, so that deformation of the filtering membrane is buffered in the filtering process, and damage to the filtering membrane caused by deformation when clamped and fixed is avoided; the radial width of the gasket accounts for less than 10% of the diameter of the filtering membrane layer, the gasket has a small effect, and the filtering membrane layer is embedded into the diversion surface in a large area, so that the risk of damage exists; the radial width of the gasket accounts for more than 30% of the diameter of the filtering membrane layer, the gasket blocks the filtering membrane layer, the effective filtering membrane area of the filtering membrane layer is affected, and the filtering efficiency of the filter is greatly reduced.

As a preferable scheme of the utility model, the bottom of the upper shell is provided with a flange, the lower shell is provided with a back-off, and the flange is clamped with the back-off in a matching way.

As a preferred embodiment of the present utility model, the needle filter further comprises: the fixing area is used for fixing the filtering membrane layer and the gasket; the fixing area comprises a first fixing area arranged on the upper shell and a second fixing area arranged on the outer edge of the lower shell, the first fixing area is provided with a plane contacted with the filtering membrane layer, and the second fixing area is provided with a plane contacted with the gasket.

As a preferable mode of the utility model, the outer edge of the second fixing area is provided with a groove.

As a preferable scheme of the utility model, the depth of the groove is increased radially along the outer edge direction of the second fixing area, the depth of the groove accounts for 0.1% -20% of the thickness of the second fixing area, and the radial width of the groove accounts for 10% -60% of the radial width of the second fixing area.

The depth of the groove is 0.1% -20% of the thickness of the second fixing area, and the gasket deforms under the action of the fixing area and is embedded into the groove, so that the overall tightness of the filter is improved; when the depth of the groove is more than 20% of the thickness of the second fixing area, the structural stability of the lower shell is affected, and especially in the forming process of the filter, the depth of the groove is too large, so that the lower shell is easy to deform additionally.

The radial width of the groove accounts for 10% -60% of the radial width of the second fixing area, the gasket part is embedded into the groove, the sealing performance of the filter is improved, a buffer cavity is provided for the downstream side of the filtering membrane layer, the lower shell is prevented from directly contacting the filtering membrane layer, and the filtering membrane layer is prevented from being damaged; when the radial width of the groove is too small, the sealing performance of the filter is not improved greatly; when the radial width of the groove is too large, the edge of the gasket, which is far away from one side of the groove, is easy to warp and press the filtering membrane layer when the filter is formed, so that the filtering membrane layer is damaged.

As a preferable scheme of the utility model, an overlapping area of the filtering membrane layer and the first fixing area on the axial projection of the filtering membrane layer is a first annular area; the overlapping area of the filtering membrane layer and the second fixing area on the axial projection of the filtering membrane layer is a second annular area; the radial width of the first annular area accounts for 5% -30% of the diameter of the filtering membrane layer; the radial width of the second annular region accounts for 5% -30% of the diameter of the filtering membrane layer.

When the radial width of the first annular area is 5-30% of the diameter of the filtering membrane layer, the radial width of the second annular area is 5-30% of the diameter of the filtering membrane layer, and the tightness of the needle filter can be further improved. When the radial width of the first annular area and/or the second annular area is too large, the effective filtering area of the filtering membrane layer is reduced, so that the filtering efficiency of the filter is reduced; when the radial width of the first annular area and/or the second annular area is too small, the fixing effect of the fixing area on the filter membrane layer is insufficient, and the filter membrane layer is easy to misplace in the forming and using process of the filter, so that the filter is invalid.

As a preferred embodiment of the present utility model, the width of the first annular region is smaller than the width of the second annular region.

As a preferred aspect of the present utility model, the filtering membrane layer includes at least one filtering membrane; the upstream side and/or the downstream side of the filtering membrane layer is/are provided with a supporting layer.

The beneficial effects of the utility model are as follows: and a gasket is arranged on the downstream side of the filtering membrane layer, so that a buffer cavity is formed between the filtering membrane layer and the lower shell, and permeate can enter the diversion surface more quickly, thereby improving the discharge efficiency of the permeate. The gasket has elasticity, can effectively avoid leading to the damage in the drainage face of filtration membrane embedding lower casing in the filtration process, improved filtration stability. Simultaneously, the filtering membrane layer is provided with the supporting layer, improves the mechanical strength of filter membrane, avoids filter membrane to take place deformation in the filtration process.

Drawings

FIG. 1 is a schematic view of a needle filter according to an embodiment of the present utility model;

FIG. 2 is an exploded view of the first embodiment of the needle filter of FIG. 1;

FIG. 3 is a bottom view of the upper housing of FIG. 2;

FIG. 4 is a partial cross-sectional view of a needle filter according to one embodiment of the utility model;

FIG. 5 is a schematic diagram showing the positional relationship between a support layer and a filtering membrane layer according to an embodiment of the present utility model;

Fig. 6 is a partial cross-sectional view of a needle filter according to a second embodiment of the present utility model.

Reference numerals: 100. an upper housing; 110. a liquid inlet channel; 120. a flange; 121. a stuck point; 130. an exhaust passage; 200. a lower housing; 210. a liquid outlet channel; 220. reversing; 230. a flow guiding surface; 240. a groove; 300. a filtration membrane layer; 400. a gasket; 510. a first fixed region; 520. a second fixed region; 600. wrapping edges; 700. and a support layer.

Detailed Description

In order to better understand the above technical solution, exemplary embodiments of the present utility model will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present utility model are shown in the drawings, it should be understood that the present utility model may be embodied in various forms and should not be limited to the embodiments set forth herein.

In the description of the present utility model, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium; may be a communication between two elements or an interaction between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Example 1

Referring to fig. 1 to 5, the present embodiment provides a needle filter, which includes an upper housing 100, a lower housing 200, a filtering membrane layer 300, and a gasket 400, wherein a liquid inlet channel 110 is disposed on a top surface of the upper housing 100, the lower housing 200 is hermetically connected with the upper housing 100 through a flange 600, and the lower housing 200 is provided with a liquid outlet channel 210. The filtering membrane layer 300 is disposed between the upper case 100 and the lower case 200, the gasket 400 is disposed downstream of the filtering membrane layer 300, and the gasket 400 at least partially overlaps the filtering membrane layer such that a buffer chamber is formed between the filtering membrane layer 300 and the lower case 200. To maintain the stability of the filtering membrane layer 300 during the filtering process, the filtering membrane layer 300 and the gasket 400 are fixed by fixing areas provided on the upper and lower cases 100 and 200.

The central area of the bottom surface of the lower housing 200 is further provided with a flow guiding surface 230, and the flow guiding surface 230 includes an annular flow channel circumferentially distributed along the bottom surface of the lower housing 200, and is radially provided with a plurality of flow guiding grooves for guiding the collected materials into the liquid outlet channel 210. To further enhance the filtering effect, two filter membrane layers 300 may also be provided. The liquid inlet channel 110 of the upper housing 100 is further vertically provided with an air outlet channel 130 communicated with the liquid inlet channel 110, and of course, the air outlet channel 130 may be obliquely arranged on the top surface of the upper housing 100 relative to the liquid inlet channel 110. During filtration, the material enters the filter through the liquid inlet channel 110 of the upper housing 100, and after the internal surplus gas is discharged through the gas outlet channel 130, the material is filtered through the filtering membrane layer 300 to obtain the permeate, and the permeate is discharged out of the needle filter along the liquid outlet channel 210 of the lower housing 200.

In some embodiments, the bottom of the upper housing 100 is provided with a flange 120, the flange 120 is provided with a protruding clip point 121, the lower housing 200 is provided with a back-off 220, and the clip point 121 and the back-off 220 are engaged with each other. The filter is also provided with a fixing area for fixing and assembling the filtering membrane layer 300 and the gasket 400, the fixing area comprises a first fixing area 510 with a flange 120 at the edge, a second fixing area 520 arranged on the bottom surface of the inner side of the lower shell, preferably, the second fixing area 520 is arranged on the outer edge area of the annular flow channel, the first fixing area 510 is provided with a contact plane contacted with the filtering membrane layer 300, the second fixing area 520 is provided with a contact plane contacted with the gasket 400, when the upper shell 100 and the lower shell 200 are assembled, a clamping gap is formed between the first fixing area 510 and the second fixing area 520, and the filtering membrane layer 300 and the gasket 400 are fixedly clamped in the clamping gap. By utilizing the structures of the upper shell 100 and the lower shell 200, the flatness of the contact surfaces of the fixed area, the filtering membrane layer 300 and the gasket 400 is ensured, the damage to the filtering membrane layer 300 caused by the fixed area is avoided, and the structure is compact and reasonable. The cooperation joint of flange 120 and back-off 220 can play the fixed effect to first fixed zone 510 and second fixed zone 520, prevents that first fixed zone 510, second fixed zone 520 from taking place relative rotation in the assembly process to improve the structural stability of needle filter in the assembly process, avoid the dislocation to appear in inner structure before the encapsulation technology.

The overlapping area of the filtering membrane layer 300 and the first fixing area 510 on the axial projection of the filtering membrane layer is a first annular area; the overlapping area of the filtering membrane layer 300 and the second fixing area 520 on the axial projection of the filtering membrane layer is a second annular area; the radial width of the first annular region accounts for 5% -30% of the diameter of the filtering membrane layer 300; the radial width of the second annular region accounts for 5% -30% of the diameter of the filtering membrane layer 300, and the width of the first annular region is smaller than the width of the second annular region, so that the gasket 400 in the first annular region can be effectively clamped, and the sealing performance of the needle filter is improved.

As a preferred solution, the radial width of the gasket 400 is smaller than the width of the second annular region, so that the gasket 400 is completely supported by the second fixing region 520 after the filter is installed, and the influence on the liquid outlet channel of the needle filter due to the deformation of the gasket 400 can be prevented.

In some embodiments, the gasket 400 is made of an elastic material, and has an elastic modulus of 2.5-18.5 mpa, a hardness of 40-70 a, a tensile strength of 3.2-10.5 mpa, an elongation at break of 500-800%, and a thickness of 150-380 μm, preferably 160-200 μm, so that unnecessary damage to the filtering membrane layer 300 caused by the gasket 400 during filtering can be avoided. On the other hand, the gasket 400 is an elastic member, so that the impact force of the material on the filtering membrane layer 300 has a buffering effect, and the filtering performance is prevented from being influenced by the tight adhesion or irreversible deformation of the filtering membrane layer 300 and the lower shell 200 caused by the overlarge impact force.

Specifically, the thickness of the gasket 400 is 200 μm, the elastic modulus is 3.0MPa, the integrity of the filtering membrane layer 300 under the pressure holding action of the fixing area can be ensured while the filtering membrane layer 300 is protected, and a buffer cavity with a certain volume is provided for the downstream side of the filtering membrane layer 300, so that the influence on filtering stability caused by too fast impact of the penetrating fluid on the guide surface is avoided. Or the gasket 400 has a thickness of 180 μm, in which case the gasket 400 provides a filter chamber of a sufficient volume to the downstream side of the filtering membrane layer 300, and the permeate can be sufficiently dispersed to enter the guide surface 230 of the lower case after passing through the filtering membrane layer 300, and the filter chamber of a proper height can also prevent the permeate from striking the guide surface 230, resulting in unnecessary influence such as denaturation of the permeate.

In some embodiments, the width of the gasket 400 is equal to or greater than the width of the first annular region. The width of the gasket 400 is 10% to 30%, preferably 14% to 20%, of the diameter of the filtering membrane layer 300.

Specifically, as shown in fig. 4, the width of the gasket 400 is the same as the width of the first annular region, and is 15% of the diameter of the filtering membrane layer 300, and the gasket 400 is completely overlapped with the first annular region. When the filter membrane layer 300 forms a seal under the clamping action of the fixing region, the gasket 400 can protect the filter membrane layer 300 from being damaged by the fixing region while further improving the sealing performance of the needle filter.

As shown in fig. 5, in this embodiment, the filtering membrane layer 300 includes at least one layer of filtering membrane, and when a plurality of layers of filtering membranes are disposed in the filtering membrane layer 300, a plurality of filtering membranes are stacked to form a filtering membrane group sheet, and non-woven fabric supporting layers 700 are disposed on the upstream side and the downstream side of the filtering membrane or the filtering membrane group sheet respectively, and by the action of the supporting layers 700, the structural stability of the filtering membrane layer 300 is further improved, so that the filtering membrane layer 300 is prevented from being damaged in the filtering process. The support layer 700 may be provided only on the upstream side or the downstream side of the filtration membrane layer as required. In addition to the nonwoven fabric, the material of the supporting layer 700 may be one or a combination of polyethylene, polypropylene and cellulose. The thickness of the support layer 700 is optionally 100-250 μm, and the air permeability of the support layer 700 is optionally 60-120 cc/cm2/sec.

Further, a binding 600 is provided at the outer circumferences of the first fixing region 510 and the second fixing region 520, and the binding 600 is integrally formed on the needle filter through an encapsulation process and is closely attached to the upper case 100 and the lower case 200. In order to ensure the mechanical strength of the upper and lower shells of the needle filter, avoid the deformation of the upper and lower shells caused by excessive pressure, and lead to the influence of filtering stability.

Example two

The structure of the lower casing 200 is improved on the basis of the first embodiment, and the groove 240 is formed in the lower casing 200, so that the edges of the gasket 400 and the filtering membrane layer 300 can deform into the groove 240 in the assembly and fixing process of the filter, and the gasket 400 and the filtering membrane layer 300 are protected to a certain extent, and the gasket 400 and the filtering membrane layer 300 are prevented from being damaged.

Specifically, in this embodiment, as shown in fig. 6, the groove 240 is configured on the outer edge of the second fixing area 520, the groove surface of the groove 240 is in a circular arc shape, in this embodiment, the depth of the groove 240 is increased radially along the second fixing area 520, the depth of the groove 240 is 0.1% -20% of the thickness of the second fixing area 520, the radial width of the groove 240 is 10% -60% of the radial width of the second fixing area 520, the groove 240 provides deformation buffering for the gasket 400, and during the assembly process of the filtering membrane layer 300 and the gasket 400, the gasket 400 is deformed towards the groove 240 under the action of the stress, so that the gasket 400 is prevented from deforming into the assembly of the upper casing 100 and the lower casing 200, thereby affecting the filtering stability.

As shown in fig. 6, the outer periphery of the gasket 400 coincides with the outer periphery of the first annular region, the width of the gasket 400 is greater than the width of the first annular region, the width of the first annular region is specifically 15% of the diameter of the filtering membrane layer 300, the width of the gasket 400 is 18% of the diameter of the filtering membrane layer 300, and the gasket can better support the filtering membrane layer 300, so that deformation of the filtering membrane layer 300 in the filtering process is better buffered, and damage to the filtering membrane layer 300 caused by deformation of the filtering membrane layer 300 when the first annular region is clamped and fixed is avoided. Meanwhile, after the filter is assembled, a certain thickness difference is generated between the part of the gasket 400 located in the groove 240 and the part located between the first fixing area 510 and the second fixing area 520 by arranging the groove 240 in the lower shell 200, so that a certain corner is generated at the junction of the lower shell 200 and the groove 240 by the gasket 400, the clamping effect of the filtering membrane layer 300 at the junction of the lower shell 200 and the groove 240 is enhanced, and the tightness of the needle filter is further improved.

In order to facilitate the formation of the groove 240 in the second fixing region 520 while ensuring that the surface of the second annular region where the groove 240 is not disposed can be stably abutted against the lower end surface of the gasket 400, the radial width of the second annular region is 10% to 30%, preferably 20%, of the diameter of the filtering membrane layer 300, and the convenience of processing the groove 240 is improved by appropriately increasing the area of the second annular region.

While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that alterations, modifications, substitutions and variations may be made in the above embodiments by those skilled in the art within the scope of the utility model.

Claims (12)

1. A needle filter comprising:

An upper housing (100), wherein the upper housing (100) is provided with a liquid inlet channel (110);

The lower shell (200) is connected with the upper shell (100) in a sealing way, and the lower shell (200) is provided with a liquid outlet channel (210);

A filtering membrane layer (300) provided between the upper case (100) and the lower case (200);

And a gasket (400) provided on the downstream side of the filtration membrane layer (300), wherein the gasket (400) at least partially overlaps the filtration membrane layer (300) so that a buffer chamber is formed between the filtration membrane layer (300) and the lower case (200).

2. A needle filter as defined in claim 1, wherein: the elastic modulus of the gasket (400) is 2.5-18.5 MPa, and the hardness is 40-70A.

3. A needle filter as defined in claim 1, wherein: the tensile strength of the gasket (400) is 3.2-10.5 MPa, and the elongation at break is 500-800%.

4. A needle filter as defined in claim 1, wherein: the thickness of the gasket (400) is 150-380 mu m.

5. A needle filter as defined in claim 1, wherein: the gasket (400) is of an annular structure, and the radial width of the gasket (400) is 10-30% of the diameter of the filtering membrane layer (300).

6. A needle filter as defined in claim 1, wherein: the bottom of the upper shell (100) is provided with a flange (120), the lower shell (200) is provided with a back-off (220), and the flange (120) and the back-off (220) are in fit and clamping connection.

7. The needle filter of claim 1, wherein the needle filter further comprises: a fixing area for fixing the filtering membrane layer (300) and the gasket (400); the fixing area comprises a first fixing area (510) arranged on the upper shell (100), a second fixing area (520) arranged on the lower shell (200), the first fixing area (510) is provided with a plane contacted with the filtering membrane layer (300), and the second fixing area (520) is provided with a plane contacted with the gasket (400).

8. A needle filter as defined in claim 7, wherein: the outer edge of the second fixing area (520) is provided with a groove (240).

9. A needle filter as defined in claim 8, wherein: the depth of the groove (240) is increased radially along the outer edge direction of the second fixing area (520), the depth of the groove (240) accounts for 0.1% -20% of the thickness of the second fixing area (520), and the radial width of the groove (240) accounts for 10% -60% of the radial width of the second fixing area (520).

10. A needle filter as defined in claim 7, wherein: an overlapping area of the filtering membrane layer (300) and the first fixing area (510) on the axial projection of the filtering membrane layer is a first annular area; an overlapping area of the filtering membrane layer (300) and the second fixing area (520) on the axial projection of the filtering membrane layer is a second annular area; the radial width of the first annular area accounts for 5% -30% of the diameter of the filtering membrane layer (300); the radial width of the second annular region accounts for 5% -30% of the diameter of the filtering membrane layer (300).

11. A needle filter as defined in claim 10, wherein: the width of the first annular region is smaller than the width of the second annular region.

12. A needle filter as defined in claim 1, wherein: the filter membrane layer (300) comprises at least one layer of filter membrane; a support layer (700) is provided on the upstream side and/or the downstream side of the filtration membrane layer (300).