Filter assemblies, depth indicators, torque limiting accessories, torque indicating accessories, and systems comprising the foregoing.

Abstract

In some instances, a filter assembly may include a filter comprising: a first washer having a first channel adjacent to a first side of the filter; and a second washer having a second channel adjacent to a second side of the filter. The first and second washers may include inclined surfaces adjacent to the filter. The first and second channels may include diameters from about 0.01 mm to about 0.5 mm. A finger-tightening system securely holds the filter without any leakage.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 047,469, filed July 2, 2020, entitled “FILTER ASSEMBLIES, DEPTHINDICATORS, TORQUE-LIMITING FITTINGS, AND SYSTEMS INCORPORATING THE SAME,” which is incorporated herein by reference in its entirety. Background Technology

[0003] High-performance liquid chromatography (HPLC) may operate at pressures exceeding 50 bar (5,000 kPa). An HPLC system may include numerous components, including replaceable and reconfigurable filters that need to be impermeable to fluids. These filters may include sintered stainless steel or plastic discs held within a housing. These filters may also be encapsulated in plastic or metal rings, which helps to seal the filter under high pressure, and because the pressurized fluid enters directly into the filter face, these filters are considered “open” filters. Attached Figure Description

[0004] The features of this disclosure are illustrated by way of example and are not limited in the following drawings, in which similar reference numerals indicate similar elements, in which:

[0005] Figure 1 This is a perspective cross-section of a system including torque limiting fittings and a filter assembly according to an example of this disclosure;

[0006] Figure 2 This is a side cross-section of a system including torque-limiting fittings according to an example of this disclosure;

[0007] Figure 3 This is a side view of a system including torque limiting accessories according to an example of this disclosure;

[0008] Figure 4 This is a distal perspective view of a drive shaft collar located within a thumb piece, according to an example of this disclosure;

[0009] Figures 5A to 5D A two-color depth indicator is depicted according to an example of this disclosure;

[0010] Figure 6A and Figure 6B A system including a dual-color depth indicator is shown as an example according to this disclosure;

[0011] Figure 7AThis is a perspective cross-section of a filter component according to an example of this disclosure;

[0012] Figure 7B This is a perspective cross-section of a protective column assembly according to an example of this disclosure;

[0013] Figure 8 This is a perspective cross-section of a system including a filter assembly according to an example of this disclosure;

[0014] Figure 9 This is a perspective cross-section of a system including a torque indicator fitting according to an example of this disclosure, the components of which may form a filter assembly, the system being used with a filter cartridge comprising a relatively short length of a first-type gasket;

[0015] Figure 10 This is an example based on this disclosure. Figure 9 A perspective view of the system used in conjunction with a relatively short filter cartridge;

[0016] Figure 11 This is an example based on this disclosure. Figure 9 A cross-sectional view of a system including torque indicator fittings, the system being used with a relatively long filter cartridge including a second type of gasket;

[0017] Figure 12 This is an example based on this disclosure. Figure 11 A perspective view of the system used in conjunction with a relatively long filter cartridge;

[0018] Figure 13 This is an example based on this disclosure. Figure 9 A perspective view of the thumb component of the system (including the driven connector in the thumb component);

[0019] Figure 14 This is an example based on this disclosure. Figure 9 A perspective view of the filter cartridge; the outer surface of the filter fittings has no threaded details.

[0020] Figure 15 This is an example based on this disclosure. Figure 9 A perspective view of the filter cartridge, showing threaded details on the outer surface of the filter fittings;

[0021] Figure 16 This is an example based on this disclosure. Figure 9 A perspective view of the driven coupling and torque-indicating drive collar of the system; and

[0022] Figure 17 This illustrates one example according to this disclosure. Figure 16A perspective view of the operation of the driven coupling and torque indicator drive collar. Detailed Implementation

[0023] For simplicity and for illustrative purposes, this disclosure is described primarily by way of examples. Numerous specific details are set forth in the following description to provide a thorough understanding of this disclosure. However, it will be apparent that this disclosure can be practiced without being limited to these specific details. In other instances, some methods and structures have not been described in detail to avoid unnecessarily obscuring this disclosure.

[0024] Throughout this disclosure, the terms "an" and "a" are intended to mean at least one of a particular element. As used herein, the term "includes" means including but not limited to, and the term "including" means including but not limited to. The term "based on" means at least partially based on.

[0025] Unless explicitly stated or obvious from the context, as used herein, the term “about” should be understood as being within the normal tolerance range in the field, such as within 2 standard deviations of the mean. “About” can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the specified value. Unless otherwise obvious from the context, all numerical values ​​provided herein are modified by the term “about”.

[0026] Unless explicitly stated or obvious from the context, the term “or” as used herein shall be understood to be inclusive.

[0027] The ranges provided herein should be understood as a simplified representation of all values ​​within the range. For example, the range 1 to 50 should be understood to include any number, combination of numbers, or subrange that comes from the following groups: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 (and their fractions, unless the context clearly indicates otherwise).

[0028] The examples described in this article relate to systems that enable fluid-impermeable connections without the need for tools such as wrenches or screwdrivers.

[0029] According to the examples disclosed herein, a filter assembly may include: a filter; a first gasket adjacent to a first side of the filter; a second gasket adjacent to a second side of the filter; a female housing; and a male housing. The male housing may be sized to concentrically fit within the female housing. Each of the male and female housings may include a bore and a stop shoulder surrounding the bore. Each of the first and second gaskets may include complementary geometries to form a seal against the respective stop shoulder.

[0030] For the aforementioned filter assembly, the bore may define a central axis. In this respect, the stop shoulder may be perpendicular to the central axis. The filter, the first washer, the second washer, the female housing, and the male housing may be radially symmetrical about the central axis.

[0031] For the filter assembly described above, the first gasket and the second gasket may each include a central axial bore.

[0032] For the filter assembly described above, the first gasket and the second gasket may include an inclined surface adjacent to the filter. The inclined surface may include an angle of approximately 70 degrees to approximately 89 degrees relative to the central axis.

[0033] For the filter assembly described above, the fluid flow pressure around the filter can generate increased sealing pressure between the complementary geometries of the first and second gaskets and the corresponding stop shoulders of the female and male housings, relative to the pre-flow state.

[0034] For the filter assembly described above, the filter assembly can be impermeable to fluid at a fluid flow pressure of 1,300 bar (130,000 kPa) without requiring a pre-flow sealing pressure of more than 13 pounds (57.8 N).

[0035] For the above-mentioned filter assembly, the male housing and the female housing can be press-fitted together or connected together by threads.

[0036] For the above-described filter assembly, the filter may include a first filter, a second filter, and a medium between the first filter and the second filter.

[0037] According to the examples disclosed herein, a filter assembly may include: a filter; a first gasket having a first channel adjacent to a first side of the filter; and a second gasket having a second channel adjacent to a second side of the filter. The first and second gaskets may include inclined surfaces adjacent to the filter. The first and second channels may include diameters from about 0.01 mm to about 0.5 mm.

[0038] According to the examples disclosed herein, a protective post assembly may include: a first filter; a second filter; a medium positioned between the first filter and the second filter; a first gasket having a first channel adjacent to the first filter; and a second gasket having a second channel adjacent to the second filter. The first gasket and the second gasket may include inclined surfaces adjacent to the first filter and the second filter, respectively. The first channel and the second channel may include a diameter of about 0.01 mm to about 0.5 mm.

[0039] According to the examples disclosed herein, a system may include: a female housing including an internal helical thread; a male housing including an external helical thread and defining an axial bore adapted and configured to receive a filter or guard post assembly; and a dual-color depth indicator positioned outside the male or female housing. The dual-color depth indicator may include a distal color and a proximal color. The distal and proximal colors may be positioned such that when the female or male housing is tightened over a mating male or female housing: if the filter assembly is correctly inserted and the dual-color depth indicator is positioned outside the male housing, the female housing may cover the proximal color, making only the distal color visible; and if the filter assembly is correctly inserted and the dual-color depth indicator is positioned outside the female housing, the cap may cover the proximal color, making only the distal color visible. If the filter assembly is incorrectly inserted or defective, both the proximal and distal colors may be visible. If the filter assembly is not inserted, the mother shell or the cover can obscure both the near-side color and the far-side color, making both the near-side color and the far-side color invisible.

[0040] For the above system, the dual-color depth indicator can be formed by at least one process, including printing, painting, electroplating, brush plating, or anodizing.

[0041] For the system described above, the dual-color depth indicator may be a ring placed on the external helical thread of the male housing. The ring may be threaded onto the external helical thread of the male housing.

[0042] For the system described above, the dual-color depth indicator may include tape, sticker, and rubber band.

[0043] For the system described above, the housing may further include a distal unthreaded portion adjacent to the internal helical thread. The distal unthreaded portion may include an axial length equal to or exceeding the axial length of the dual-color depth indicator.

[0044] In the above system, the far-side color can be green and the near-side color can be red.

[0045] According to the examples disclosed herein, a torque limiting accessory may include a driven coupling comprising: a sealing region; and at least one driven tooth, the at least one driven tooth including an inclined rotational tail surface in the sealing direction of the driven coupling. A drive collar may include at least one drive tooth positioned to engage with the at least one driven tooth when the drive collar is rotated.

[0046] The torque limiting accessory described above may further include an elastic member, which is adjacent to the drive shaft collar.

[0047] For the aforementioned torque limiting accessory, the thumb member may cover at least the drive collar and the elastic member. The thumb member may include: a notch that receives the drive collar and the elastic member; and at least one forward limiting feature adapted and configured to limit axial movement of the thumb member.

[0048] For the aforementioned torque limiting fitting, the sealing area may include a helical thread. The sealing area may be located on the distal end of the driven connector.

[0049] For the aforementioned torque limiting accessory, the at least one driven tooth may be located on the proximal end or radial outer surface of the driven connector.

[0050] For the torque limiting accessory described above, the at least one drive tooth may include an asymmetrical profile that rotates in the opposite direction to the at least one driven tooth.

[0051] For the aforementioned torque limiting accessory, the drive collar may further include at least one axial collar alignment feature. The at least one axial collar alignment feature may be located radially outside or inside the at least one drive tooth. The at least one forward limiting feature may include a stop shoulder.

[0052] For the aforementioned torque limiting fitting, the thumb member and the driven coupling may further include complementary features to hold the thumb member and the driven coupling together with the drive collar and the resilient member held therebetween. The complementary features may include: a first radial undercut; and at least one of a second radial undercut and / or at least one boss.

[0053] For the aforementioned torque limiting components, the driven coupling and the drive collar may be made of metal.

[0054] For the torque limiting accessory described above, the elastic member may include a wave spring.

[0055] For the aforementioned torque limiting accessory, the thumb member may include a knurled outer surface. The thumb member may also include at least one axial thumb member alignment feature complementary to at least one axial collar alignment feature.

[0056] According to the examples disclosed herein, a filter assembly may include a driven connector capable of engaging with a filter fitting of a filter cartridge. The driven connector may include: a bore for receiving the filter fitting; and a stop shoulder surrounding the bore to restrict movement of the driven connector relative to the filter fitting.

[0057] For the filter assembly described above, the driven connector may include an internal thread for threaded engagement with the external thread of the filter fitting.

[0058] For the aforementioned filter assembly, the stop shoulder of the filter fitting may be perpendicular to the central axis of the filter assembly.

[0059] For the above-described filter assembly, the driven connector, the filter fitting, and the filter cartridge may be radially symmetrical about the central axis of the filter assembly.

[0060] The filter assembly described above may further include a thumb member capable of engaging with the driven connector to rotate the driven connector.

[0061] According to the examples disclosed herein, a filter cartridge may include: a first filter fitting located on one side of a filter; a second filter fitting located on a second opposite side of the filter; a first gasket disposed in the first filter fitting; and a second gasket disposed in the second filter fitting.

[0062] For the aforementioned filter cartridge, the first filter accessory and the second filter accessory may include external threads.

[0063] For the aforementioned filter cartridge, the first gasket and the second gasket may include complementary geometries to form a seal against the stop shoulder of the first filter fitting and the stop shoulder of the second filter fitting, respectively.

[0064] For the aforementioned filter cartridge, the stop shoulder of the first filter accessory and the stop shoulder of the second filter accessory may be perpendicular to the central axis of the filter cartridge.

[0065] For the above-mentioned filter cartridge, the first filter accessory, the second filter accessory, the first gasket, and the second gasket may be radially symmetrical about the central axis of the filter cartridge.

[0066] For the filter cartridge described above, the first gasket and the second gasket may each include a central axial bore.

[0067] For the filter cartridge described above, the first gasket and the second gasket may include an inclined surface adjacent to the filter. The inclined surface may include an angle of approximately 70 degrees to approximately 89 degrees relative to the central axis of the filter cartridge.

[0068] According to the examples disclosed herein, a torque indicating accessory may include: a driven coupling including at least one driven tooth; and a torque indicating drive collar including at least one drive tooth positioned to engage with the at least one driven tooth when the torque indicating drive collar is rotated. The torque indicating drive collar may further include at least one torque indicating tooth positioned adjacent to the at least one drive tooth to engage with the at least one driven tooth when the torque indicating drive collar is rotated.

[0069] The torque indicating accessory may further include: an elastic member adjacent to the torque indicating drive collar; and a thumb member covering at least the torque indicating drive collar and the elastic member. The thumb member may include: a notch accommodating the torque indicating drive collar and the elastic member; and at least one forward limiting feature adapted and configured to limit axial movement of the thumb member.

[0070] For the torque indicating accessory described above, the at least one driven tooth may be located on the proximal end or radial outer surface of the driven connector.

[0071] For the torque indicating accessory described above, the torque indicating drive collar may further include at least one axial collar alignment feature. The at least one axial collar alignment feature may be located radially outside or inside the at least one drive tooth.

[0072] For the torque indicator accessory described above, the at least one forward restraint feature may include a stop shoulder.

[0073] For the aforementioned torque indicating accessory, the thumb member and the driven connector may further include complementary features to hold the thumb member and the driven connector together with the torque indicating drive collar and the resilient member held therebetween. The complementary features may include a thumb member protrusion and a driven connector protrusion.

[0074] For the aforementioned torque indicating accessory, the driven connector and the torque indicating drive collar may be made of metal.

[0075] For the aforementioned torque indicating accessory, the elastic component can be a wave spring.

[0076] For the aforementioned torque indicator accessory, the thumb component may include a knurled outer surface.

[0077] For the torque indicating accessory described above, the thumb member may further include at least one axial thumb member alignment feature that is complementary to at least one axial collar alignment feature.

[0078] Figure 1 Provided for filter assembly 102 or guard post 700b ( Figure 7BFor example, a partial cross-section of system 100 coupled to a liquid chromatography system. System 100 may include fittings 104a and 104b, a driven coupling 108, a thumb member 110, a drive collar 120, a resilient member 126 (such as a spring), and a cap 134. In one example, the driven coupling 108 may be rotatably positioned about fitting 104a. The drive collar 120 may be positioned on top of the driven coupling 108 such that it can engage or disengage from the driven coupling 108 via the resilient member 126. The resilient member 126 may be positioned on top of or adjacent to the drive collar 120 such that when a predetermined amount of torque is applied by rotating the thumb member 110, the resilient member 126 allows the drive collar 120 to disengage from the driven coupling 108. Thus, in this example, the thumb member 110 is positioned and connected to the resilient member 126 and the drive collar 120. By rotating the thumb fitting 110, the user can cause the drive collar 120 to engage and rotate the driven connector 108, thereby removably connecting the driven connector 108 to the outer surface of the fitting 104, thus connecting fitting 104a to fitting 104b. The filter assembly 102 can be held between and fluidly coupled to fittings 104a and 104b, which can be coupled to other components of the LC system, for example, by forging and other techniques. The filter assembly 102 can be held between fittings 104a and 104b via a connection between the driven connector 108 (which may be in the form of a female housing) and fitting 104b (which may be in the form of a male housing). In one example, a portion of the inner surface of the driven connector 108 may include a sealing region, for example, a set of helical threads 106 corresponding to a portion of the outer surface of fitting 104b, said portion including a second sealing region, for example, a set of second helical threads 106. By connecting the helical thread 106 of the driven connector 108 and the helical thread 106 of the fitting 104b, the fittings 104a and 104b can securely hold the filter assembly 102.

[0079] Torque limiting accessories

[0080] refer to Figure 2 In one example, system 100 may provide a torque limiting accessory. This controls the torque applied to the driven connector 108 when the user rotates the thumb piece 110, for example, to prevent damage to the component and facilitate later removal. In one example, the force applied to the driven connector 108 may be about 1 pound force (lbf) or less, up to about 32 lbf; for example, the force may be about 2 lbf to about 24 lbf, about 3 lbf to about 13 lbf, such as about 5 lbf.

[0081] like Figure 3As best seen, the driven coupling 108 may include one or more asymmetrical driven teeth 112. The asymmetrical driven teeth 112 may include a rotating leading surface 114 and a rotating trailing surface 116. When in the sealing direction (e.g., in...), Figure 3 When the driven connector 108 is rotated counterclockwise in the depicted example, the rotating trailing surface 116 has a lower slope than the rotating leading surface 114. Examples of the slope of the trailing surface 116 (relative to the radial plane) may include less than about 90°, such as about 45°, about 45° to about 15°, about 30° to about 15°, about 22.5°, etc. Examples of the slope of the surface 114 (relative to the radial plane) may include about 90° or less, such as about 90° to about 75°, about 85° to about 75°, etc.

[0082] The driven coupling 108 can be driven by a drive collar 120 having one or more drive teeth 122, said one or more drive teeth 122 being positioned to rotate when the drive collar 120 is rotated by a force applied by a user to the thumb member 110 (e.g. Figure 1 and Figure 2 (As shown) meshes with one or more asymmetric driven teeth 112. The drive teeth 122 may, but need not, have a profile that is opposite to the asymmetric profile of the asymmetric driven teeth 112. In some instances, the slopes are the same, which can promote frictional engagement between the drive teeth 122 and the asymmetric driven teeth 112.

[0083] refer to Figure 3 and Figure 4 The drive collar 120 may include one or more axial collar alignment features 124. Although Figure 3 and Figure 4 The axial collar alignment feature 124 depicted is a radially outer boss or ridge, but the axial collar alignment feature 124 can be a radially inner groove, etc.

[0084] An elastic member 126 adjacent to the drive collar 120 presses the drive collar 120 against the driven coupling 108. The drive collar 120 can slide axially within an axial thumb alignment feature 128 complementary to one or more axial collar alignment features 124. The properties of the various components can be configured to allow the drive tooth 122 to frictionally engage and drive the asymmetric driven tooth 112 until a predetermined amount of torque is applied (e.g., the driven coupling 108 forms a threaded seal with the helical thread 106 on the surface of the fitting 104b and resists further rotation). When the torque exceeds the configured threshold, the drive tooth 122 will slip and overcome the axial force applied by the elastic member 126. Therefore, the drive collar 120 will slide proximally within the thumb 110. The surface 114 with a higher slope will better resist slippage and ensure easy removal even if the driven coupling 108 is tightened to the point where the tooth slips.

[0085] like Figure 1 and Figure 2 As best seen, the thumb member 110 may cover at least the drive collar 120 and the resilient member 126, which may rest in a proximal recess to allow deformation of the resilient member 126 and axial movement of the drive collar 120. The thumb member 110 may be held by one or more features, such as radial undercuts 130a, 130b on the driven connector 108 and the thumb member 110 respectively, which allow the thumb member 110 to rotate over the driven connector 108 when the teeth 112, 122 slip during tightening.

[0086] Still referencing Figure 1 and Figure 2 The thumb member 110 and / or driven connector 108 may include one or more forward limiting features 132a-132d, such as a stop shoulder adapted and configured to limit or prevent axial movement of the thumb member 110. These forward limiting features 132a-132d prevent the user from overcoming torque limiting features by pressing the thumb member 110 distally during rotation. This further loads the resilient member 126 and / or drive collar 120 and reduces or prevents slippage of the drive teeth 122 and the ability of the drive collar 120 to slide proximally.

[0087] The thumb piece 110 may, but does not need to, be knurled, rough, or include one or more features to help the fingers tighten.

[0088] Visual Depth Indicator

[0089] Now for reference Figures 5A to 5D Some instances of system 100 may include a dual-color depth indicator 500. The dual-color depth indicator 500 may include two color regions 502 and 504 with different colors. These regions may be arranged axially such that color region 502 is proximal to the radially outer component 506 (e.g., the cover component), while color region 504 is distal to it.

[0090] The dual-color depth indicator 500 can be positioned on an external surface so that the user can observe the dual-color depth indicator 500 and use it to assess whether the system is correctly assembled. For example, refer to... Figure 2A dual-color depth indicator 500 may be positioned on the outer surface of the driven connector 108 and the outer surface of the fitting 104b, etc. (if the cover 134 can slide distally so that the user can see the fitting 104b). In another example, the driven connector 108 may include two color areas 502 and 504. In this example, color area 502 may be the exterior of the driven connector 108, corresponding to the threaded portion in the inner surface of the driven connector 108. Furthermore, color area 504 may correspond to the remaining exterior portion of the driven connector 108. When the user screws the driven connector 108 onto the outer surface of the fitting 104b, the cover 134 initially covers the outer surface of the driven connector 108 with color area 502. When the driven connector 108 is fully connected to the fitting 104b, the cover 134 may completely cover color area 502; therefore, only color area 504 is visible to the user. The visibility indicator of a single color area 504 is fully secured to the accessory 104b by the driven connector 108.

[0091] The dual-color depth indicator 500 can be positioned along an outer surface partially covered by another component 506 (e.g., driven connector 108 in the case of accessory 104b, cover 134 in the case of driven connector 108, etc.). The radially outer component 506 is depicted as partially transparent so that the dual-color depth indicator 500 can be observed below. In some instances, the radially outer component 506 may be optically opaque.

[0092] Now for reference Figure 5B If the components are not assembled correctly or are defective, the near-side color area 502 and the far-side color area 504 can be seen.

[0093] Now for reference Figure 5C If the components are assembled correctly, only the far-side color area 504 will be visible.

[0094] Now for reference Figure 5D If a component (e.g., filter assembly 102) is missing, neither the proximal color region 502 nor the distal color region 504 will be visible.

[0095] Figure 6A and Figure 6B A system including a dual-color depth indicator 500 is shown. Figure 6A Both the proximal color area 502 (red) and the distal color area 504 (green) are visible, indicating that the radially outer component 506 (e.g., the thumb piece) may require further tightening or that the filter assembly 102 is defective or incorrectly installed. Figure 6B In the middle, only the distal color 504 (green) is visible, which indicates that the radially outer part 506 (e.g., the thumb piece) is properly tightened.

[0096] The two-color depth indicator 500 can be either ring-shaped or strip-shaped. The two-color depth indicator 500 can be formed using various processes such as printing, painting, electroplating, brush plating, and anodizing. The two-color depth indicator 500 can be made of tape, sticker, rubber band, etc. In one example, the two-color depth indicator 500 can be one or two pre-installed (e.g., mounted on an external helical thread via threaded connection, adhesive, etc.) colored rings.

[0097] Filter components

[0098] Now for reference Figure 7A Another example provides a filter assembly 700a. The filter assembly 700a advantageously remains fluid-impermeable when subjected to elevated fluid pressures without requiring significant pre-tightening of the system 100, for example, by a force exceeding 7 pounds (approximately 58 N), said elevated fluid pressures being, for example, greater than 50 bar (5,000 kPa), 350 bar (35,000 kPa), 1,000 bar (100,000 kPa), 1,300 bar (130,000 kPa), etc.

[0099] Filter 702 is held within filter assembly 700a and can be of the type used in HPLC. For example, filter 702 can be a sintered frit, such as 300 series sintered steel.

[0100] Gaskets 704a and 704b may be located proximal and distal to filter 702. Gaskets 704a and 704b define a first channel 706a and a second channel 706b for fluid inflow and outflow. The first channel 706a and the second channel 706b may (e.g., axially) be centered and / or surrounded by external gasket faces 708a and 708b to form a seal with fittings 104a and 104b, such as... Figure 8 Best visible. In one instance, each of the first channel 706a and the second channel 706b may include a diameter of about 0.01 mm or less to about 0.9 mm, such as about 0.1 mm to about 0.5 mm, or a diameter such as about 0.3 mm.

[0101] Filter 702 and gaskets 704a, 704b are held between female housing 712 and male housing 710. Female housing 712 and male housing 710 can be held together by a variety of techniques, including interference fit, press fit, friction fit, shrinkage fit, threaded connection, welding, ultrasonic welding, adhesives, fasteners, etc. In some instances, female housing 712 and male housing 710 are held together by one or more features, such as radial undercut 714 and corresponding bosses or ridges 716. In some instances, female housing 712 and male housing 710 are assembled using a press and sold as a single unit to the end user. In one instance, female housing 712 may be made of a polymer, metal, or a combination of metals. For example, female housing may be made of steel (such as 17-4 steel). Similarly, male housing 710 may be made of metal or a combination of metals. For example, male housing may be made of steel (such as 300 series steel).

[0102] Gaskets 704a and 704b may include one or more geometric features adapted and configured to provide a fluid-impermeable seal under pressure. For example, gaskets 704a and 704b may include stop shoulders 720a and 720b that are complementary to stop shoulders 722a and 722b of a bore (e.g., an axial bore) surrounding gaskets 704a and 704b.

[0103] Gaskets 704a and 704b may also include inclined surfaces 718a and 718b adjacent to filter 702. Inclined surfaces 718a and 718b may have a tapered profile centered on the first channel 706a and the second channel 706b. The angle may be from about 5° to about 20° (relative to the radial plane). In other examples, the angle relative to the central axis may be from about 70 degrees (e.g., 20° relative to the radial plane) to about 89 degrees (e.g., 1° relative to the radial plane).

[0104] During operation, the fluid pressure on the inclined surfaces 718a, 718b can primarily generate axial sealing pressure against the stop shoulders 722a, 722b and / or radial sealing pressure against the male housing 710. Therefore, the higher the fluid pressure, the higher the sealing pressure and the less fluid-permeable the filter assembly 700a. Thus, a finger-tightening force of approximately 3 lbf to approximately 13 lbf (e.g., approximately 5 lbf to approximately 8 lbf) on the system 100 is sufficient to completely seal the filter assembly 700a without requiring further external tightening of the system 100.

[0105] In another example, the protective post 700b can advantageously remain impermeable to fluid without being tightened before significant flow, for example, by a force exceeding 13 pounds (approximately 57.8 N), when subjected to elevated fluid pressures, such as greater than 50 bar (5,000 kPa), 350 bar (35,000 kPa), 1,000 bar (100,000 kPa), 1,300 bar (130,000 kPa), etc.

[0106] In this example, the guard column 700b may include a first filter 702a, a second filter 702b, and a medium 703 positioned between the first filter 702a and the second filter 702b. The first filter 702a, the second filter 702b, and the medium 703 may be of any type used in HPLC, including but not limited to ultra-high performance liquid chromatography (UHPLC). For example, filters 702a and / or 702b may be sintered frits made of metal, polymer, or combinations thereof. In this example, the medium 703 may be made of particles such as metals, metal oxides, polymers, carbon (e.g., spherical activated carbon, or carbon on silica materials), silica-based particles or general versions thereof, activated carbon, stationary phase, etc. In other examples, the medium 703 may include other types of materials optimized for solvent removal and other such uses. The media and / or particles disclosed herein may be used in any of the filters disclosed herein, and / or other types of columns, in-line solid-phase extraction (SPE), etc. One or more of filters 702a, 702b and / or media 703 may also be made of an integral structure.

[0107] Gasket 704a may be located proximal to filter 702a, and gasket 704b may be located distal to filter 702b. Gaskets 704a and 704b define a first channel 706a and a second channel 706b for fluid inflow and outflow. Each of the first channel 706a and the second channel 706b may be (e.g., axially) centered and / or surrounded by outer gasket faces 708a and 708b to form a seal with fittings 104a and 104b. In one example, each of the first channel 706a and the second channel 706b may include a diameter of about 0.01 mm or less to about 0.9 mm, such as about 0.1 mm to about 0.5 mm, or a diameter such as about 0.3 mm.

[0108] Each of filters 702a, 702b, media 703, and gaskets 704a, 704b is held between the female housing 712 and the male housing 710. The female housing 712 and the male housing 710 can be held together by a variety of techniques, including interference fit, press fit, friction fit, shrinkage fit, threaded connection, welding, ultrasonic welding, adhesives, fasteners, etc. In some instances, the female housing 712 and the male housing 710 are held together by one or more features, such as a radial undercut 714 and a corresponding boss or ridge 716. In some instances, the female housing 712 and the male housing 710 can be assembled using a press and sold as a single unit to the end user.

[0109] Gaskets 704a and 704b may include one or more geometric features adapted and configured to provide a fluid-impermeable seal under pressure. For example, gaskets 704a and 704b may include stop shoulders 720a and 720b that are complementary to stop shoulders 722a and 722b of bores (e.g., axial bores) surrounding gaskets 704a and 704b.

[0110] Gaskets 704a and 704b may also include inclined surfaces 718a and 718b adjacent to filters 702a and 702b. Inclined surfaces 718a and 718b may have a tapered profile centered on the first channel 706a and the second channel 706b. The angle may be approximately 5° to approximately 20° (relative to the radial plane).

[0111] During operation, the fluid pressure on the inclined surfaces 718a and 718b primarily generates axial sealing pressure against the stop shoulders 722a and 722b, and / or radial sealing pressure against the male housing 710. Therefore, the higher the fluid pressure, the higher the sealing pressure and the less fluid-permeable the guard post 700b. Thus, a finger-tightening force of approximately 3 lbf to approximately 13 lbf (e.g., approximately 5 lbf to approximately 8 lbf) on system 100 is sufficient to completely seal the filter assembly 700a without requiring further external tightening of system 100.

[0112] Example

[0113] Design of open-face filter elements (prior art) and currently invented closed-face in-line filter ( Figure 7B The test was conducted to apply the preload required for sealing at a given pressure. The pressure was generated using isopropanol by an Agilent 1290 Infinity IILC pump. A schematic diagram of the test fixture is shown below. Figure 9 )

[0114] Procedure: Insert the filter into the clamp resting on the sealing block. Tighten the compression ring to a preload reading of 5 psi, pressing the filter between the sealing block and the nut body. The test will begin, and if the set pressure (bar) is not reached, the compression ring will be further tightened, increasing the load. Once the pressure graph shows the desired pressure has been reached, and once the flow graph shows the leakage rate is no longer decreasing, the compression ring is no longer tightened, and the system remains at the set pressure. Each run lasts approximately 90 seconds. At the end of the test, the pressure is restored to ambient pressure. Record the current load reading (psi) and the resulting leakage rate (µL / min). Test the open and closed configurations with three filters, respectively, at 200 bar, 400 bar, and 600 bar.

[0115] Open surface filter

[0116]

[0117] Closed-face filter

[0118]

[0119] All open-face filters require high preload to form a seal and result in a fairly high leakage rate. Closed-face filter cartridges require minimal preload (finger tightening) to achieve a leak-free seal.

[0120] Torque indicator accessories

[0121] Figure 9 This is a perspective cross-section of a system 900 including a torque indicator fitting 902 according to an example of this disclosure. Components of the torque indicator fitting 902 may form a filter assembly 904. The system 900 is used with a relatively short filter cartridge 906 including a first-type gasket 908. Figure 10 This is a perspective view of a system 900 according to an example of this disclosure, which is used with a filter cartridge 906 of relatively short length. Figure 11 This is a perspective cross-section of a system 1100 including a torque indicator accessory 902 according to an example of this disclosure, the system 1100 being used with a relatively long filter cartridge 1102 including a second type gasket 1104. Figure 12 This is a perspective view of a system 1100 according to an example of this disclosure, which is used with a filter cartridge 1102 of relatively long length.

[0122] refer to Figure 9 and Figure 10A filter assembly 904, which may include any two or more components of a torque indicating fitting 902, may include a driven coupling 910 capable of engaging with a filter fitting 912 of a filter cartridge 906. The filter assembly 904 may also include the torque indicating drive collar 914 disclosed herein. The driven coupling 910 may include a bore 916 for receiving the filter fitting 912, and a stop shoulder 918 surrounding the bore 916 to limit movement of the driven coupling 910 relative to the filter fitting 912.

[0123] The stop shoulder 918 of the filter fitting 912 may be perpendicular to the central axis 920 of the filter assembly 904. The driven connector 910, the filter fitting 912, and the filter cartridge 906 may be radially symmetrical about the central axis 920 of the filter assembly 904.

[0124] Driven connector 910 may include internal thread 922 for threaded engagement with external thread 924 of filter fitting 912 (see also: [link to other document]). Figure 15 ).

[0125] for Figure 9 For example, gasket 908 may include a complementary geometry 926 whose diameter decreases toward the center of filter cartridge 906. For instance, the diameter of gasket 908 decreases from a larger diameter adjacent to fitting 928 to a smaller diameter adjacent to frit 954. In this way, gasket 908 can form a seal against the corresponding filter fitting.

[0126] Torque indicator fitting 902 and relatively short filter cartridge 906 can be fluidly coupled to fittings 928 and 930, which can be further coupled to other components of the liquid chromatography (LC) system, for example, by die forging and other techniques.

[0127] The filter assembly 904 may also include a thumb member 932 capable of engaging with the driven connector 910 to rotate the driven connector 910. Figure 13 This is a perspective view of a thumb member 932 (including a driven connector 910 in the thumb member 932) of a system 900 (and 1100) according to an example of this disclosure.

[0128] like Figure 9 As shown, the torque indicating accessory 902 may further include a resilient member 944 adjacent to the torque indicating drive collar 914. A thumb member 932 may cover at least the torque indicating drive collar 914 and the resilient member 944. The thumb member 932 may include a recess 946 for receiving the torque indicating drive collar 914 and the resilient member 944, and at least one forward limiting feature 948 adapted and configured to limit axial movement of the thumb member 932. At least one forward limiting feature 948 may include a stop shoulder.

[0129] The thumb member 932 and the driven connector 910 may also include complementary features to hold the thumb member 932 and the driven connector 910 together with the torque-indicating drive collar 914 and the resilient member 944 held therebetween. The complementary features may include the thumb member protrusion 950 and the driven connector protrusion 952.

[0130] refer to Figure 9 and Figure 16 The thumb member 932 may also include at least one axial collar alignment feature 1616 that aligns with the torque-indicating drive collar 914 (see, for example, see...). Figure 16 At least one complementary axial thumb alignment feature (similar to) Figure 4 (Thumb component alignment feature 128). In Figure 16 In the example, the axial collar alignment feature 1616 is shown as a radially outer boss or ridge, but may be changed to include a radially inner groove, etc.

[0131] In some instances, the thumb piece 932 may include a knurled outer surface. The knurled outer surface facilitates (e.g., by hand) manual rotation of the thumb piece 932 to attach the torque indicator fitting 902 to the filter cartridge 906 (or 1102) or to remove the torque indicator fitting 902 from the filter cartridge 906 (or 1102).

[0132] The filter assembly 904 advantageously remains impermeable to fluid when subjected to elevated fluid pressures without the need for significant pre-flow tightening of the system 900, for example, by a force exceeding 7 pounds (approximately 58 N), such elevated fluid pressures as greater than 50 bar (5,000 kPa), 350 bar (35,000 kPa), 1,000 bar (100,000 kPa), 1,300 bar (130,000 kPa), etc.

[0133] Sintered frit 954 (such as 300 series sintered steel) can be disposed on both sides of filter 934 between gasket 908 and filter 934 to prevent particles of a specified size (e.g., too large for the application of system 900) from entering passage 956.

[0134] According to the examples disclosed herein, the driven connector 910 and the torque-indicating drive collar 914 may be made of polymer, metal, or a combination of metals. For example, the driven connector 910 and the torque-indicating drive collar 914 may be made of steel (such as 17-4 steel). Furthermore, the elastic member 944 may be a wave spring, or another type of elastic member.

[0135] Filter 934 can be of any type used in HPLC, including but not limited to UHPLC. For example, filter 934 can be formed of steel or another material (such as a biocompatible metal). In this example, the media that may be included in passage 956 may be made of particles such as metals, metal oxides, polymers, carbon (e.g., spherical activated carbon, or carbon on a silica material), silica-based particles or a general version thereof, activated carbon, stationary phase, etc. In other examples, the media may include other types of materials optimized for solvent removal and other such uses. The media and / or particles disclosed herein may be used in any of the filters disclosed herein, and / or other types of columns, in-line solid-phase extraction (SPE), etc.

[0136] In some instances, the filter 934, with a relatively short length, may be approximately 30 mm long, compared to the filter 1106 of the relatively long filter cartridge 1102, which may be approximately 50 mm long. In this respect, the passage 956 of the relatively short filter cartridge 906 may include a diameter of approximately 2.1 mm, compared to the passage 1122 of the relatively long filter cartridge 1102, which may have a diameter of approximately 4.6 mm. Both filters 934 and 1106 can be used in HPLC and UHPLC applications.

[0137] Figure 14 This is a perspective view of a filter cartridge 906 according to an example of this disclosure, with no threaded details on the outer surface 1400 of the filter fitting 912. Figure 15 This is a perspective view of a filter cartridge 906 according to an example of this disclosure, wherein the outer surface of the filter fitting 912 has threaded details (e.g., external thread 924).

[0138] refer to Figure 9 , Figure 14 and Figure 15 Filter cartridge 906 may be included in filter 934 (or Figure 11 The filter fitting 912 (e.g., the first filter fitting 912) on one side of the filter 1106, and on the filter 934 (or Figure 11 The second filter fitting 936 is located on the second opposite side of the filter 1106. (See reference) Figure 11 , Figure 14 and Figure 15 The filter cartridge 1102 may be included in the filter 1106 (or Figure 9 The first filter fitting 1108 on one side of the filter 934), and on the filter 1106 (or Figure 9 The second filter fitting 1110 is on the second opposite side of the filter 934. Figure 9 and Figure 11As shown, filter fittings 912 and 936 may include configurations different from those of filter fittings 1108 and 1110 to accommodate gaskets 908 and 1104, respectively.

[0139] like Figure 9 As shown, the filter cartridge 906 may include a gasket 908 (e.g., a first gasket) disposed in the filter fitting 912 (e.g., a first filter fitting) and a gasket 908 (e.g., a second gasket) disposed in the filter fitting 936 (e.g., a second filter fitting). Figure 11 As shown, the filter cartridge 1102 may include a gasket 1104 (e.g., a first gasket) disposed in a filter fitting 1108 (e.g., a first filter fitting), and a gasket 1104 (e.g., a second gasket) disposed in a filter fitting 1110 (e.g., a second filter fitting). Gaskets 908 and 1104 may include different configurations, such as... Figure 9 and Figure 11 As shown.

[0140] like Figure 9 As shown, washer 908 (e.g., in...) Figure 9 The first washer located on the left and the second washer located on the right may include complementary geometries 926 to form a seal against the region 938 of the first filter fitting 912 and the region 940 of the second filter fitting 936, respectively.

[0141] for Figure 9 Examples include the first filter fitting 912, the second filter fitting 936, and the gasket 908 (e.g., in...). Figure 9 The first washer on the left and the second washer on the right are radially symmetrical about the central axis of the filter cartridge 906 (which may coincide with the central axis 920).

[0142] Washer 908 (e.g., in Figure 9 The first washer on the left and the second washer on the right (oriented in terms of orientation) may include a central axial channel 942. In one example, the channel 942 may include a diameter of about 0.01 mm or less to about 0.9 mm, such as about 0.1 mm to about 0.5 mm, or a diameter such as about 0.3 mm.

[0143] The gasket 908 may include an inclined surface 958 adjacent to the filter 934 (the molten block 954 is disposed between the inclined surface 958 and the filter 934). The inclined surface 958 may include an angle of about 70 degrees to about 89 degrees relative to the central axis of the filter cartridge (which may coincide with the central axis 920).

[0144] The gasket 908 may also include a protruding surface 960, which may include an angle of about 85 degrees to about 89 degrees (such as about 87 degrees) relative to a plane perpendicular to the central axis of the filter cartridge (which may coincide with the central axis 920).

[0145] During operation, the fluid pressure on the inclined surface 958 primarily generates axial sealing pressure against the molten metal 954 and / or radial sealing pressure against the filter assembly. Therefore, the higher the fluid pressure, the higher the sealing pressure and the less fluid-permeable the filter assembly 904 becomes. Thus, a finger-tightening force of approximately 3 lbf to approximately 13 lbf (e.g., approximately 5 lbf to approximately 8 lbf) on the system 900 is sufficient to completely seal the filter assembly 904 without requiring further external tightening of the system 900.

[0146] like Figure 11 As shown, washer 1104 (e.g., in...) Figure 11 The first washer located on the left and the second washer located on the right (oriented in terms of orientation) may include complementary geometries to form a seal against the stop shoulder 1116 of the first filter fitting 1108 and the stop shoulder 1118 of the second filter fitting 1110, respectively. The stop shoulder 1116 of the first filter fitting 1108 and the stop shoulder 1118 of the second filter fitting 1110 may be perpendicular to the central axis of the filter cartridge 1102 (which may coincide with the central axis 920).

[0147] for Figure 11 Examples include the first filter fitting 1108, the second filter fitting 1110, and the gasket 1104 (e.g., in...). Figure 11 The first washer on the left and the second washer on the right (oriented in terms of orientation) are radially symmetrical about the central axis of the filter cartridge 1102 (which may coincide with the central axis 920). Washer 1104 (e.g., in...) Figure 11 The first washer on the left and the second washer on the right (oriented in terms of orientation) may include a central axial channel 1112. In one example, the channel 1112 may include a diameter of about 0.01 mm or less, up to about 0.9 mm, such as about 0.1 mm to about 0.5 mm, or such as about 0.3 mm.

[0148] Gasket 1104 may include an inclined surface 1114 adjacent to filter 1106. Inclined surface 1114 may include an angle of about 70 degrees to about 89 degrees relative to the central axis of the filter cartridge (which may coincide with the central axis 920).

[0149] The gasket 1104 may also include a protruding surface 1124, which may include an angle of about 85 degrees to about 89 degrees (such as about 87 degrees) relative to a plane perpendicular to the central axis of the filter cartridge (which may coincide with the central axis 920).

[0150] During operation, the fluid pressure on the inclined surface 1114 can primarily generate axial sealing pressure against the molten metal 1120 and / or radial sealing pressure against the filter assembly. Therefore, the higher the fluid pressure, the higher the sealing pressure and the less fluid-permeable the filter assembly 904 becomes. Thus, a finger-tightening force of approximately 3 lbf to approximately 13 lbf (e.g., approximately 5 lbf to approximately 8 lbf) on the system 1100 is sufficient to completely seal the filter assembly 904 without requiring further external tightening of the system 1100.

[0151] refer to Figure 9 and Figure 15 Filter fittings 912, 936, 1108, and 1110 may include external threads (e.g., external thread 924). In this respect, driven coupling 910 may include internal threads 922 for threaded engagement with the external threads 924 of filter fittings 912, 936, 1108, and 1110.

[0152] A sintered frit 1120 (which may be 300 series sintered steel) may be disposed on both sides of the filter 1106 between the gasket 1104 and the filter 1106 to prevent particles of a specified size from entering the passage 1122.

[0153] Filter 1106 can be of any type used in HPLC, including but not limited to UHPLC. For example, filter 1106 may be formed of steel or another material (such as a biocompatible metal). In this example, the media that may be included in passage 1122 may be made of particles such as metals, metal oxides, polymers, carbon (e.g., spherical activated carbon, or carbon on a silica material), silica-based particles or a general version thereof, activated carbon, stationary phase, etc. In other examples, the media may include other types of materials optimized for solvent removal and other such uses. The media and / or particles disclosed herein may be used in any of the filters disclosed herein, and / or other types of columns, in-line solid-phase extraction (SPE), etc.

[0154] Figure 16 This is an example based on this disclosure. Figure 9 A perspective view of the driven coupling 910 and torque indication drive collar 914 of the system 900. Figure 17 This illustrates one example according to this disclosure. Figure 16 A perspective view of the operation of the driven coupling 910 and the torque indicator drive collar 914.

[0155] refer to Figure 9 , Figure 16 and Figure 17The torque indicating accessory 902 may include: a driven connector 910, which includes at least one driven tooth 1600; and a torque indicating drive collar 914, which includes at least one drive tooth 1602, the at least one drive tooth 1602 being positioned to engage with the at least one driven tooth 1600 when the torque indicating drive collar 914 is rotated. Each driven tooth 1600 may include a trapezoidal configuration, wherein the outer surface 1604 of the driven tooth 1600 includes a larger surface area compared to the inner surface 1606. In this respect, a line along the edge 1608 (which may be sharp or rounded) may terminate at the center point along the central longitudinal axis 1610 of the driven connector 910. Furthermore, at least one driven tooth 1600 may be located on the proximal end or radially outer surface of the driven connector 910. Examples of the slope of the drive tooth 1602 (relative to the radial plane) may include less than about 90°, such as about 45°, about 45° to about 15°, about 30° to about 15°, about 22.5°, etc.

[0156] The torque indicating drive collar 914 may further include at least one torque indicating tooth 1612, which is positioned adjacent to the at least one drive tooth 1602 to engage with the at least one driven tooth 1600 when the torque indicating drive collar 914 is rotated. A line along the edges (which may be sharp or rounded) of the drive tooth 1602 and the torque indicating tooth 1612 may similarly terminate at the center point along the central longitudinal axis 1614 of the torque indicating drive collar 914.

[0157] The torque-indicating drive collar 914 may also include at least one axial collar alignment feature 1616. The at least one axial collar alignment feature 1616 may be located radially outside or inside the at least one drive tooth 1602.

[0158] The properties of various components of the torque indicating accessory 902 can be configured to allow the drive tooth 1602 to frictionally engage with the driven tooth 1600 and drive the driven tooth 1600 until a predetermined amount of torque is applied (e.g., the driven connector 910 forms a threaded seal with the corresponding filter accessory).

[0159] about Figure 9 , Figure 11 and Figure 17 To describe the operation of system 900.

[0160] refer to Figure 9 , Figure 11 and Figure 17 At 1700, thumb piece 932 (not in) Figure 17(As shown in the figure) can be used to rotate the torque indicator drive collar 914, which can impart rotation to the driven coupling 910 based on the contact between the drive tooth 1602 and the driven tooth 1600.

[0161] The torque applied to the driven connector 910 when the user rotates the thumb piece 932 can be controlled, for example to prevent damage to components and to facilitate subsequent removal of the torque indicator accessory 902 from the filter cartridge. In one example, the force applied to the driven connector 910 can be about 1 pound force (lbf) or less up to about 32 lbf, for example, the force can be about 2 lbf to about 24 lbf, about 3 lbf to about 13 lbf, such as about 5 lbf.

[0162] At 1702, when the torque applied to the driven tooth 1600 reaches the maximum specified torque equal to (e.g., when the elastic member 944 is compressed) the maximum specified torque of the reaction force applied by the elastic member 944, as shown at 1704, the torque-indicating drive collar 914 may disengage from the driven coupling 910 due to the angled contact between the angled surface 1706 of the drive tooth 1602 and the driven tooth 1600.

[0163] At 1708, as the torque indicator drive collar 914 continues to rotate and the angled surface 1706 of the drive tooth 1602 no longer contacts the driven tooth 1600, the torque indicator drive collar 914 is free to rotate until the driven tooth 1600 contacts the torque indicator tooth 1612. At this point, the contact between the driven tooth 1600 and the torque indicator tooth 1612 produces an audible and physical "click," which can be heard and felt by the thumb rest 932, indicating to the user that the torque indicator fitting 902 is correctly installed on the filter cartridge 906 (or 1102) to avoid any accidental leakage associated with the system 900. Once the torque indicator fitting is correctly installed on both sides of the filter cartridge 906 (or 1102), the user can utilize the system 900 as needed.

[0164] Examples of materials

[0165] The various components described in this article can be made from a variety of materials, including metals and polymers. These materials can be engineered to achieve the desired levels of strength, elasticity, etc.

[0166] In some instances, the driven couplings 208 and / or 910, as well as the drive collars 220 and / or 914, are made of metal (such as steel alloys, such as stainless steel). The surfaces of the teeth 212, 222, 1600, 1602, and / or 1612 may be engineered (e.g., by machining or surface treatment) to have defined smoothness or roughness, which will affect the torque at which the teeth 212, 222, 1600, 1602, and / or 1612 slip and / or maintain contact.

[0167] In some instances, gaskets 704a, 704b, 908, and / or 1104 may be made from the following materials: polymers, plastics, elastomers, rubber, silicone, nitrile, polytetrafluoroethylene (PTFE). (Available under the label), polychlorotrifluoroethylene, polyetheretherketone (PEEK), metals, etc.

[0168] The examples and variations thereof are described and illustrated herein. The terminology, descriptions, and figures used herein are for illustrative purposes only and are not intended to be limiting. Numerous variations are possible within the spirit and scope of the subject matter intended to be defined by the following claims and their equivalents, and unless otherwise stated, all terms in the claims shall be interpreted in their broadest reasonable sense.

Claims

1. A system comprising: A female housing, the female housing including an internal helical thread; Male housing, the male housing including external helical threads and defining an axial bore, the axial bore being adapted and configured to receive a filter or guard post assembly; as well as A dual-color depth indicator, positioned outside the male housing or the female housing, the dual-color depth indicator comprising: Far side color; and Near-side color, The distal and proximal colors are positioned such that when the female or male housing is screwed onto the mating male or female housing: If the filter assembly is correctly inserted and the dual-color depth indicator is positioned outside the male housing, the female housing covers the proximal color so that only the distal color is visible, and if the filter assembly is correctly inserted and the dual-color depth indicator is positioned outside the female housing, the cover covers the proximal color so that only the distal color is visible. If the filter assembly is incorrectly inserted or defective, both the proximal and distal colors will be visible; and If the filter assembly is not inserted, the outer shell or the cover obscures both the near-side color and the far-side color, making both the near-side color and the far-side color invisible.

2. The system of claim 1, wherein the dual-color depth indicator is formed by at least one process, the process including printing, painting, electroplating, brush plating or anodizing.

3. The system of claim 1, wherein the dual-color depth indicator is a ring placed on the external helical thread of the male housing.

4. The system of claim 3, wherein the ring is threaded onto the external helical thread of the male housing.

5. The system of claim 1, wherein the dual-color depth indicator comprises tape, sticker, and rubber band.

6. The system of claim 1, wherein the female housing further includes a distal unthreaded portion adjacent to the internal helical thread, the distal unthreaded portion including an axial length equal to or greater than the axial length of the dual-color depth indicator.

7. The system of claim 1, wherein: The distal side is green; and The color of the proximal side is red.

Images