A filter for a cryoablation device

Abstract

This utility model belongs to the field of filtration technology and discloses a filter for a cryoablation device, including a cylindrical body, a first filter element, and a second filter element. The cylindrical body has openings at both ends. The first filter element is disposed at the first end opening of the cylindrical body, and the second filter element is disposed at the second end opening of the cylindrical body. The cylindrical body, the first filter element, and the second filter element form a closed filtration chamber, which is filled with a molecular sieve for adsorbing moisture in the refrigerant flowing through the filtration chamber, and is not suitable for absorbing nitrous oxide. The minimum particle size of the molecular sieve is larger than the pore size of the first and second filter elements. The molecular sieve filling the cylindrical body of this application can effectively remove moisture from the refrigerant (nitrous oxide), improve the cooling effect of the cryoablation device, and ensure the stable operation of the cryoablation device. The first and second filter elements, disposed at the two end openings of the cylindrical body, prevent molecular sieve leakage and allow the refrigerant to pass smoothly.

Description

Technical Field

[0001] This utility model relates to the field of filtration technology, and more particularly to a filter for cryoablation equipment. Background Technology

[0002] Cryoablation technology is currently widely used to treat rapid cardiac arrhythmias, such as atrial fibrillation (AF). Its working principle involves using a liquid refrigerant to absorb heat and evaporate, removing heat from the tissue and lowering the temperature of the target ablation site. This "freezes" the cells and tissues, destroying areas of abnormal electrophysiological activity, thus achieving the goal of treating the arrhythmia. Liquid nitrous oxide (N2O) is widely used as the refrigerant in cryoablation equipment due to its unique physicochemical properties.

[0003] Currently, gas plants cannot completely eliminate the presence of water during the preparation of nitrous oxide. Typically, liquid nitrous oxide contains approximately 20 ppm of water. During cryoablation, liquid nitrous oxide is pumped directly from the gas cylinder into the cryoablation system. Studies show that higher purity nitrous oxide is beneficial for the normal operation of the cryoablation equipment and for achieving the required low temperature of -45 degrees Celsius. The presence of water interferes with the cooling effect of the refrigerant, preventing the equipment from reaching the ideal low temperature and thus affecting the treatment outcome.

[0004] Existing cryoablation equipment lacks an effective device for filtering moisture from liquid nitrous oxide. The presence of moisture affects the cooling effect of the refrigerant, thus impacting the normal operation of the cryoablation equipment. Therefore, developing a device capable of effectively filtering moisture from nitrous oxide is crucial to addressing this issue and improving the therapeutic efficacy of cryoablation. Utility Model Content

[0005] The purpose of this application is to provide a filter for cryoablation equipment that can filter water from nitrous oxide and improve the effect of cryotherapy.

[0006] The technical solution provided in this application is as follows:

[0007] A filter for a cryoablation device, comprising:

[0008] The cylindrical body has openings at both ends;

[0009] The first filter element is disposed at the first end opening of the cylinder;

[0010] The second filter element is disposed at the second end opening of the cylinder;

[0011] The cylinder, the first filter, and the second filter form a closed filtration cavity. The filtration cavity is filled with molecular sieves, which are used to adsorb moisture in the refrigerant flowing through the filtration cavity and are not suitable for absorbing nitrous oxide.

[0012] The minimum particle size of the molecular sieve is larger than the pore size of the first filter and the second filter.

[0013] In some embodiments, the molecular sieve is a 4A molecular sieve, and the particle size range of the 4A molecular sieve is 0.5 mm to 1 mm.

[0014] In some embodiments, both the first filter and the second filter are porous sintered metal sheets with a pore size range of 30 μm to 100 μm, used to allow the refrigerant to pass through and to intercept particles of the molecular sieve.

[0015] In some embodiments, an end cap is also included, the end cap having a closed end and an open end;

[0016] The opening end of the end cap is sealed to the second end opening of the cylinder, and the second filter is fixedly disposed inside the opening end of the end cap. The side wall of the end cap is provided with a radial outlet.

[0017] In some embodiments, an outer casing is also included, which covers the cylinder and the end cap;

[0018] A first flow channel is formed between the inner wall of the outer shell and the outer wall of the cylinder, and the radial outlet connects the filter cavity and the first flow channel.

[0019] In some embodiments, a base is also included, which is sealed to the housing, and the base is provided with an air inlet and an air outlet, the air outlet being in communication with the first flow channel;

[0020] The first end of the cylinder is sealed to the base, and the air inlet is connected to the outside of the first filter.

[0021] The refrigerant entering through the air inlet passes through the first filter and enters the filter chamber for filtration. The filtered refrigerant then enters the first flow channel through the radial outlet and is discharged through the air outlet.

[0022] In some embodiments, the air inlet is connected to the filter chamber to form a second flow channel, and the first flow channel and the second flow channel form a U-shaped flow channel.

[0023] In some embodiments, the base includes a base body and a mounting part, and the side wall of the base body is provided with the air inlet and the air outlet;

[0024] The mounting part protrudes from the base body and has an assembly hole that communicates with the air inlet. The first end of the cylinder is inserted into the assembly hole, and a sealed connection is formed between the outer wall of the first end of the cylinder and the inner wall of the mounting part. An axial channel is provided on the mounting part outside the assembly hole, and the air outlet communicates with the first flow channel through the axial channel.

[0025] In some embodiments, a first sealing ring and a second sealing ring are also included;

[0026] The first sealing ring is disposed between the outer wall of the end cap and the inner wall of the second end of the cylinder; the second sealing ring is disposed between the outer wall of the first end of the cylinder and the inner wall of the assembly hole.

[0027] In some embodiments, a first pressure ring is also included, which is fixedly disposed at the first end opening of the cylinder and located on the side of the first filter sheet away from the filter cavity, for axially fixing the first filter sheet;

[0028] and / or;

[0029] It also includes a second pressure ring, which is disposed at the open end of the end cap and located on the side of the second filter sheet near the cylinder, for axially fixing the second filter sheet.

[0030] The technical advantages of this application are as follows: the filter chamber is filled with molecular sieves, which have a strong adsorption capacity for moisture, effectively removing moisture from the refrigerant (nitrous oxide), improving the cooling effect of the cryogenic ablation equipment, and ensuring the stable operation of the cryogenic ablation equipment; the first and second filter sheets are set at the openings at both ends of the cylinder, which not only fix the molecular sieve and prevent leakage, but also block larger particles of impurities from entering the filter chamber, thereby protecting the molecular sieve from contamination by impurities, extending the service life of the molecular sieve, and further improving the purity of the refrigerant. Attached Figure Description

[0031] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0032] Figure 1 This is a cross-sectional view of a filter provided in an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the structure of a filter provided in one embodiment of this application;

[0034] Figure 3 This is a schematic diagram of the structure of the first filter provided in an embodiment of this application;

[0035] Figure 4This is a cross-sectional view of a filter provided in another embodiment of this application;

[0036] Figure 5 This is a schematic diagram of the end cap structure provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of the structure of the outer casing provided in the embodiments of this application;

[0038] Figure 7 This is a schematic diagram of the structure of the base provided in the embodiment of this application;

[0039] Figure 8 This is a schematic diagram of the structure of a filter provided in another embodiment of this application;

[0040] Figure 9 This is a schematic diagram of the structure of the first pressure ring provided in the embodiment of this application.

[0041] Explanation of icon numbers:

[0042] 10. Cylinder; 11. Filter chamber; 12. Molecular sieve; 20. First filter element; 30. Second filter element; 40. End cap; 41. Radial outlet; 51. First sealing ring; 52. Second sealing ring; 53. Third sealing ring; 60. Outer shell; 61. First flow channel; 70. Base; 701. Air inlet; 702. Air outlet; 71. Base body; 711. Through hole; 72. Mounting part; 721. Assembly hole; 722. Axial channel; 80. Bracket; 91. First pressure ring; 92. Second pressure ring. Detailed Implementation

[0043] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific implementation methods of this application will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort.

[0045] To keep the drawings concise, each drawing only schematically shows the parts relevant to this application, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of the components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0046] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0047] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; or they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) are relative rather than absolute when describing the structure and movement of the various components, and are not intended to limit the direction of the product during actual use.

[0049] Furthermore, in the description of this application, ordinal numbers, such as "first" and "second," are used only to distinguish related objects and should not be construed as indicating or implying the relative importance or order between related objects.

[0050] like Figures 1 to 3 As shown, in one or more embodiments, this disclosure provides a filter for a cryoablation device, including a cylindrical body 10, a first filter 20, and a second filter 30. The cylindrical body 10 has openings at both ends. The first filter 20 is disposed at the first end opening of the cylindrical body 10. The second filter 30 is disposed at the second end opening of the cylindrical body 10. The cylindrical body 10, the first filter 20, and the second filter 30 surround to form a closed filter cavity 11. The filter cavity 11 is filled with a molecular sieve 12, which is used to adsorb moisture in the refrigerant flowing through the filter cavity 11 and is not suitable for absorbing nitrous oxide. The minimum particle size of the molecular sieve 12 is larger than the pore size of the first filter 20 and the second filter 30.

[0051] In this embodiment, the filter is installed between the gas cylinder and the cryoablation equipment. When the cryoablation equipment is running, the nitrous oxide refrigerant flows out of the gas cylinder, first into the filter, where it is dried and filtered, and then flows out of the filter into the piping system of the cryoablation equipment to remove moisture from the nitrous oxide refrigerant.

[0052] Specifically, the filter includes a cylinder 10, a first filter element 20, and a second filter element 30. The cylinder 10 is the main body of the filter and is used to support the molecular sieve 12. The cylinder 10 is generally cylindrical with a hollow structure in the middle. Its cross-section can be circular, elliptical, or rectangular, etc. This embodiment does not limit the specific shape of the cylinder 10. The material of the cylinder 10 needs to have good pressure resistance and corrosion resistance to adapt to the operating environment of the refrigerant in the cryogenic ablation equipment. Preferably, in this embodiment, the material of the cylinder 10 is SUS316, which is not only resistant to nitrous oxide corrosion but also has high structural strength and is not easy to rust.

[0053] The cylinder 10 has openings at both ends along the axial direction. A first filter 20 is provided at one end of the cylinder 10 opening, and a second filter 30 is provided at the other end opening. The first filter 20 and the second filter 30 are tightly fitted with the cylinder 10 to form a closed filtration chamber 11. The first filter 20 and the second filter 30 have the same structure, both being porous sintered metal sheets. For example, the first filter 20 and the second filter 30 are made of copper powder and have a microporous structure. The pore size of the first filter 20 and the second filter 30 ranges from 30μm to 100μm. They are used to allow the refrigerant to pass through and to intercept molecular sieve particles, that is, to allow nitrous oxide to pass through smoothly while preventing molecular sieve particles from passing through.

[0054] The filter chamber 11 is filled with a molecular sieve 12, which is a synthetic aluminosilicate with a microporous cubic lattice. The molecular sieve 12 adsorbs or repels molecules of different substances based on the size of its internal pores, hence its name. Substances with a molecular diameter smaller than the pore diameter of the molecular sieve crystal can enter the crystal and be adsorbed; otherwise, they are repelled. The molecular sieve 12 determines the preferential adsorption order based on the polarity of different molecules. It selectively adsorbs molecules based on their size and shape, meaning it only adsorbs molecules smaller than the pore size. It exhibits selective adsorption properties for small polar and unsaturated molecules; the greater the polarity and the higher the degree of unsaturation, the stronger the selective adsorption.

[0055] In this embodiment, the molecular sieve 12 has micropores that can selectively adsorb moisture in the refrigerant. Since the minimum particle size of the molecular sieve 12 is larger than the pore size of the first filter 20 and the second filter 30, the molecular sieve 12 is stably confined within the filter chamber 11 during the filtration process and will not be lost with the flow of the refrigerant.

[0056] When the cryoablation equipment is running, the refrigerant (nitrous oxide) flows out of the gas cylinder, first through the first filter 20 into the cylinder 10, and then through the molecular sieve 12 in the filter chamber 11 for drying and filtration. It then flows out of the filter chamber from the second filter 30 and into the pipeline system to reduce the moisture content in nitrous oxide from 20 ppm to 1-5 ppm, effectively reducing the moisture content in nitrous oxide.

[0057] In this embodiment, the filter chamber 11 is filled with a molecular sieve 12. The molecular sieve 12 has a strong adsorption capacity for moisture, which can effectively remove moisture from the refrigerant (nitrous oxide). In the cryoablation equipment, the dryness of the refrigerant is crucial to the performance and reliability of the equipment. The presence of moisture may reduce the thermal conductivity of the refrigerant, decrease the cooling effect, and may even cause it to freeze and block the pipes at low temperatures, affecting the normal operation of the cryoablation equipment. Through the adsorption effect of the molecular sieve 12, moisture in the refrigerant can be eliminated, ensuring the stable operation of the cryoablation equipment.

[0058] In addition, the first filter 20 and the second filter 30 not only fix the molecular sieve 12 and prevent it from leaking, but also block larger particles of impurities from entering the filter chamber 11, thereby protecting the molecular sieve 12 from contamination by impurities, extending the service life of the molecular sieve 12, and further improving the purity of the refrigerant.

[0059] In some embodiments, the molecular sieve 12 is a 4A molecular sieve, with a particle size range of 0.5 mm to 1 mm. 4A molecular sieve is an alkali metal aluminosilicate with high adsorption capacity, strong selectivity, high static adsorption, and high temperature resistance. It can adsorb molecules with a critical diameter of no more than 4A, such as water, sulfur dioxide, and carbon dioxide, but does not adsorb molecules with a diameter greater than 4A. This selective adsorption characteristic means that 4A molecular sieve cannot effectively remove moisture from the refrigerant during the drying process, while retaining other small molecule components. The high selective adsorption performance of 4A molecular sieve for water results in good moisture removal efficiency from the refrigerant by the filter.

[0060] The structure of 4A molecular sieves is very similar to that of sodium chloride, belonging to the cubic crystal system. Because the effective pore size of 4A molecular sieves is 0.4 nm, it is called 4A molecular sieve. Its spatial network structure is composed of alternating silicon-oxygen tetrahedral silicon dioxide units and aluminum-oxygen tetrahedral aluminum oxide units. The main reason why 4A molecular sieves can dry is their unique pore structure and extremely strong water absorption capacity. 4A molecular sieves are spherical with a diameter of 0.5 mm-1 mm. The smaller size of the molecular sieve 12 effectively increases the contact area between the refrigerant and the surface of the molecular sieve 12, reduces the voids in the inner core of the molecular sieve 12, and increases the filtration effect of the molecular sieve 12.

[0061] In some embodiments, such as Figure 4 and Figure 5 As shown, the filter also includes an end cap 40, which has a closed end and an open end; the open end of the end cap 40 is sealed to the second end opening of the cylinder 10, and the second filter element 30 is fixedly disposed inside the open end of the end cap 40, and the side wall of the end cap 40 is provided with a radial outlet 41.

[0062] In this embodiment, the end cap 40 is fixed to the second end opening of the cylinder 10 by means of threaded connection, snap-fit, etc. The second filter 30 is disposed inside the open end of the end cap 40, that is, the second filter 30 is installed at the second end opening of the cylinder 10 through the end cap 40. The second filter 30 and the end cap 40 can form an integral unit. When replacing the molecular sieve 12 inside the cylinder 10, it is only necessary to remove the end cap 40 as a whole from the cylinder 10. At this time, the second filter 30 is also removed along with the end cap 40. This method is easier to operate than directly disassembling the filter, so as to facilitate the maintenance or replacement of the molecular sieve 12 and improve maintainability. There is a certain distance between the closed end of the end cap 40 and the second filter 30 to form a cavity inside the end cap 40, which can play a role in buffering or rectifying. The side wall of the end cap 40 is provided with one or more radial outlets 41, which are evenly distributed circumferentially for discharging filtered nitrous oxide gas.

[0063] In this embodiment, the end cap 40 is made of SUS316 stainless steel. The end cap 40 is cylindrical in shape, closed at one end and open to the outside at the other. A stepped portion is provided on the inner wall of the cylinder 10 to restrict the position of the end cap 40. A groove for installing the first sealing ring 51 is provided on the outer wall of the end cap 40. The first sealing ring 51 is installed in this groove, achieving a sealed connection between the end cap 40 and the cylinder 10. The first sealing ring 51 is made of nitrile rubber, which is resistant to nitrous oxide corrosion, has good elasticity, and good sealing performance, thus serving to seal against nitrous oxide.

[0064] In some embodiments, such as Figure 4 and Figure 6 As shown, the filter also includes a housing 60, which covers the cylinder 10 and the end cap 40; a first flow channel 61 is formed between the inner wall of the housing 60 and the outer wall of the cylinder 10, and a radial outlet 41 connects the filter chamber 11 and the first flow channel 61.

[0065] The outer casing 60 covers the cylinder 10 and end cap 40, providing protection for them. A first flow channel 61 is formed between the inner wall of the outer casing 60 and the outer wall of the cylinder 10. The first flow channel 61 provides additional flow space for the refrigerant, allowing it to flow more smoothly during filtration. The design of the first flow channel 61 helps reduce the flow resistance of the refrigerant inside the filter, reducing pressure loss and thus improving filtration efficiency.

[0066] The end cap 40 has a radial outlet 41 on its side wall, which connects the filter chamber 11 and the first flow channel 61. The radial outlet 41 allows the refrigerant, after drying and filtration, to flow from the filter chamber 11 into the first flow channel 61, thus achieving a change in direction and an extension of the flow path of the refrigerant within the filter. This design makes the flow of the refrigerant within the filter more uniform, helps to improve the adsorption effect of the molecular sieve 12, and ensures that the moisture in the refrigerant is removed more thoroughly.

[0067] In this embodiment, the outer shell 60 is made of SUS316 stainless steel, integrally machined, and features high structural strength, corrosion resistance, high dimensional accuracy, and high hardness. The outer shell 60 serves to protect and secure the internal structure. In other embodiments, the outer shell 60 may also be made of other metal materials.

[0068] In some embodiments, such as Figure 4 , Figure 7 and Figure 8 As shown, the filter also includes a base 70, which is sealed to the outer casing 60. The base 70 has an air inlet 701 and an air outlet 702, with the air outlet 702 communicating with the first flow channel 61. The first end of the cylinder 10 is sealed to the base 70, and the air inlet 701 communicates with the outside of the first filter element 20. The air inlet 701 communicates with the filter chamber 11 to form a second flow channel, and the first flow channel 61 and the second flow channel form a U-shaped flow channel. The refrigerant entering through the air inlet 701 passes through the first filter element 20 and enters the filter chamber 11 for filtration. The filtered refrigerant enters the first flow channel 61 from the radial outlet 41 and is discharged from the air outlet 702.

[0069] The base 70 is fixedly connected to the outer shell 60, forming an integral structure that provides stable support for the cylinder 10. In this embodiment, the base 70 is made of SUS316 stainless steel, integrally machined, and has high structural strength, corrosion resistance, high dimensional accuracy, and high hardness. In other embodiments, the base 70 may also be made of other metal materials. The upper end of the outer shell 60 is cylindrical and hollow inside to accommodate the cylinder 10 and the end cap 40, while the other end of the outer shell 60 is rectangular. The dimensions of the outer shell 60 can be designed according to actual needs. In this embodiment, an exemplary dimension of the outer shell 60 is: the outer diameter of the cylindrical part is 63 mm, the length is 70.7 mm, and the wall thickness is 5 mm; the length, width, and height of the rectangular part are 82 mm, 72 mm, and 10 mm, respectively. Multiple through holes are distributed around the rectangular part of the outer shell 60; multiple threaded through holes are provided on the base 70 at corresponding positions. Screws pass through the through holes on the outer shell 60 and the base 70 to achieve a fixed connection between the outer shell 60 and the base 70. The outer casing 60 and the base 70 can be assembled and fixed by multiple three-joint hex socket screws or other types of screws. The base 70 is connected to a right-angle bracket 80 by screws. The right-angle bracket 80 facilitates the fixing of the filter to other structures. In this embodiment, the bracket 90 is a sheet metal with a certain thickness, made of SUS316, which is not only resistant to nitrous oxide corrosion, but also has high structural strength and is not easy to rust.

[0070] During operation, 1000psi high-pressure nitrous oxide flows in through the inlet 701 of the base, first passing through the first filter 20 into the filter chamber 11 of the cylinder 10. The molecular sieve 12 in the filter chamber 11 adsorbs the moisture in the nitrous oxide. The dried nitrous oxide then flows out through the second filter 30, then into the end cap 40, and finally through the radial outlet 41 on the end cap 40 into the first flow channel 61 between the cylinder 10 and the outer shell 60. Finally, it flows out through the outlet 702 on the base 70. The nitrous oxide containing moisture flows into the filter, is dried, and then flows out of the filter, reducing the moisture content to 1-5ppm, thus lowering the probability of ice blockage and improving the cooling effect.

[0071] In this embodiment, the base 70 is provided with an air inlet 701 and an air outlet 702, so that the air inlet and outlet channels of the filter are integrated on the base 70, simplifying the connection between the filter and external pipelines and reducing the risk of refrigerant leakage. The refrigerant enters through the air inlet 701 on the base 70, passes through the first filter 20 and enters the filter chamber 11. After being adsorbed by the molecular sieve 12 in the filter chamber 11, it flows into the first flow channel 61 from the radial outlet 41 on the side wall of the end cap 40, and finally exits through the air outlet 702 on the base 70. This flow path design makes the flow of refrigerant inside the filter more orderly and smooth, avoiding the stagnation and short-circuiting of refrigerant inside the filter, and improving filtration efficiency and filtration quality.

[0072] In some embodiments, such as Figure 7 As shown, the base 70 includes a base body 71 and a mounting part 72. The side wall of the base body 71 is provided with an air inlet 701 and an air outlet 702. The mounting part 72 protrudes from the base body 71 and is provided with an assembly hole 721 that communicates with the air inlet 701. The first end of the cylinder 10 is inserted into the assembly hole 721, and a sealed connection is formed between the outer wall of the first end of the cylinder 10 and the inner wall of the mounting part 72. An axial channel 722 is provided on the mounting part 72 outside the assembly hole 721, and the air outlet 702 communicates with the first flow channel 61 through the axial channel 722.

[0073] The mounting part 72 is cylindrical, with an assembly hole 721 in the middle, which communicates with the air inlet 701. The mounting part 72 extends into the gap between the cylinder 10 and the outer shell 60 to seal the opening of the first flow channel 61. An axial channel 722 is provided on the side wall of the mounting part 72, connecting the first flow channel 61 and the air outlet 702. A groove for installing the third sealing ring 53 is formed on the outer side wall of the mounting part 72. The third sealing ring 53 is installed in this groove. The side wall of the mounting part 72 is inserted into the outer shell 60, and the sealing connection between the outer shell 60 and the base 70 is achieved through the third sealing ring 53. The third sealing ring 53 is made of nitrile rubber, which is resistant to nitrous oxide corrosion, has good elasticity, and good sealing performance, thus sealing nitrous oxide. The base body 71 is rectangular, with multiple through holes 711 of 10 mm diameter around its perimeter, which helps to reduce weight. Meanwhile, a threaded through hole is provided on the base body 71 to fix the base 70 to the outer shell 60.

[0074] A groove for installing the second sealing ring 52 is provided on the outer side wall of the first end of the cylinder 10. After the second sealing ring 52 is installed in the groove, it is located between the outer side wall of the cylinder 10 and the inner side wall of the mounting hole 721 to achieve a sealed connection between the cylinder 10 and the mounting part 72. The second sealing ring 52 is made of nitrile rubber, which has the characteristics of being resistant to nitrous oxide corrosion, having good elasticity, and having good sealing performance, and plays the role of sealing nitrous oxide.

[0075] In this embodiment, the mounting part 72 protrudes from the base body 71, and an assembly hole 721 is provided inside the mounting part 72, which facilitates the insertion of the mounting part 72 between the cylinder 10 and the outer shell 60, thereby facilitating the sealed connection between the cylinder 10 and the mounting part 72, as well as the sealed connection between the mounting part 72 and the outer shell 60.

[0076] In some embodiments, such as Figure 1 , Figure 4 and Figure 9 As shown, the filter also includes a first pressure ring 91, which is fixedly disposed at the first end opening of the cylinder 10 and located on the side of the first filter 20 away from the filter chamber 11, for axially fixing the first filter 20.

[0077] In this embodiment, a stepped portion is provided inside the first end of the cylinder 10, and the inner side of the first filter element 20 is disposed on this stepped portion. A first pressure ring 91 is disposed on the outer side of the first filter element 20. The first pressure ring 91 is threadedly connected to the cylinder 10. After the first pressure ring 91 is fixed inside the cylinder 10, it can press and fix the first filter element 20 without obstructing the passage of refrigerant. The first pressure ring 91 is a ring screw made of SUS316, which is not only resistant to nitrous oxide corrosion but also has high structural strength and is not easy to rust. In other embodiments, the first filter element 20 can also be directly fixed inside the cylinder 10 by welding, threaded connection, or other methods.

[0078] In some embodiments, such as Figure 1 and Figure 4 As shown, the filter also includes a second pressure ring 92. The structure of the second pressure ring 92 is the same as that of the first pressure ring 91. The second pressure ring 92 is disposed at the open end of the end cap 40 and located on the side of the second filter element 30 near the cylinder 10, for axially fixing the second filter element 30. A stepped portion may be provided inside the end cap 40, and the inner side of the second filter element 30 is disposed on this stepped portion. The second pressure ring 92 is disposed on the outer side of the second filter element 30. The second pressure ring 92 can be threadedly connected to the cylinder 10. After the second pressure ring 92 is fixed inside the end cap 40, it can press and fix the second filter element 30. The second pressure ring 92 is a ring screw made of SUS316, which is not only resistant to nitrous oxide corrosion, but also has high structural strength and is not easy to rust. In other embodiments, the second filter element 30 can also be directly fixed inside the cylinder 10 by welding, threaded connection, or other methods.

[0079] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0080] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of this application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A filter for cryoablation equipment, characterized in that, include: The cylindrical body has openings at both ends; The first filter element is disposed at the first end opening of the cylinder; The second filter element is disposed at the second end opening of the cylinder; The cylinder, the first filter, and the second filter form a closed filtration cavity. The filtration cavity is filled with molecular sieves, which are used to adsorb moisture in the refrigerant flowing through the filtration cavity and are not suitable for absorbing nitrous oxide. The minimum particle size of the molecular sieve is larger than the pore size of the first filter and the second filter.

2. A filter for a cryoablation device according to claim 1, characterized in that, The molecular sieve is a 4A molecular sieve, and the particle size range of the 4A molecular sieve is 0.5mm-1mm.

3. A filter for a cryoablation device according to claim 2, characterized in that, Both the first filter and the second filter are porous metal sintered sheets with a pore size range of 30μm-100μm, used to allow the refrigerant to pass through and to intercept particles of the molecular sieve.

4. A filter for a cryoablation device according to claim 1, characterized in that, It also includes an end cap having a closed end and an open end; The opening end of the end cap is sealed to the second end opening of the cylinder, and the second filter is fixedly disposed inside the opening end of the end cap. The side wall of the end cap is provided with a radial outlet.

5. A filter for a cryoablation device according to claim 4, characterized in that, It also includes an outer casing, which covers the cylinder and the end cap; A first flow channel is formed between the inner wall of the outer shell and the outer wall of the cylinder, and the radial outlet connects the filter cavity and the first flow channel.

6. A filter for a cryoablation device according to claim 5, characterized in that, It also includes a base, which is sealed to the outer shell. The base is provided with an air inlet and an air outlet, and the air outlet is connected to the first flow channel. The first end of the cylinder is sealed to the base, and the air inlet is connected to the outside of the first filter. The refrigerant entering through the air inlet passes through the first filter and enters the filter chamber for filtration. The filtered refrigerant then enters the first flow channel through the radial outlet and is discharged through the air outlet.

7. A filter for a cryoablation device according to claim 6, characterized in that, The air inlet is connected to the filter chamber to form a second flow channel, and the first flow channel and the second flow channel form a U-shaped flow channel.

8. A filter for a cryoablation device according to claim 6, characterized in that, The base includes a base body and a mounting part, and the side wall of the base body is provided with the air inlet and the air outlet; The mounting part protrudes from the base body and has an assembly hole that communicates with the air inlet. The first end of the cylinder is inserted into the assembly hole, and a sealed connection is formed between the outer wall of the first end of the cylinder and the inner wall of the mounting part. An axial channel is provided on the mounting part outside the assembly hole, and the air outlet communicates with the first flow channel through the axial channel.

9. A filter for a cryoablation device according to claim 8, characterized in that, It also includes a first sealing ring and a second sealing ring; The first sealing ring is disposed between the outer wall of the end cap and the inner wall of the second end of the cylinder; the second sealing ring is disposed between the outer wall of the first end of the cylinder and the inner wall of the assembly hole.

10. A filter for a cryoablation device according to claim 4, characterized in that, It also includes a first pressure ring, which is fixedly disposed at the first end opening of the cylinder and located on the side of the first filter sheet away from the filter chamber, for axially fixing the first filter sheet; and / or; It also includes a second pressure ring, which is disposed at the open end of the end cap and located on the side of the second filter sheet near the cylinder, for axially fixing the second filter sheet.

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