Vent assembly with alternating media segments

Abstract

Some embodiments of the present technology relate to a breather port assembly. The breather port assembly has a breather port housing having a first end and a second end. The breather port housing defines a mounting structure and an airflow path extending from the mounting structure to an environment outside of the breather port housing. A plurality of filter media segments are arranged in series along the airflow path. The plurality of segments are disposed across the airflow path. The plurality of filter media segments includes efficiency segments and spacer segments, the efficiency segments and the spacer segments alternating in the series. Each spacer segment has a flow resistance rate that is up to 80% of a flow resistance rate of each efficiency segment.

Description

[0001] This application claims the benefit of U.S. Provisional Application 63 / 619,200, filed January 9, 2024, the subject of which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure generally relates to vent assemblies. More specifically, this disclosure relates to a vent assembly having alternating media sections. Background Technology

[0003] Various types of gearboxes (such as automotive transmissions, differential cases, and powertrain units) typically require some form of vent—a vent that allows for pressure equalization between the gearbox and the external environment. Some vents incorporate filter media to prevent contaminants (such as dust and fluids) from entering the gearbox. For example, a microporous membrane can be used to prevent water from entering the gearbox. However, oil particles present in the gearbox can be suspended in the air and fall into the membrane. Oil coalescing filter media can be used to prevent the membrane from becoming clogged with oil. Some coalescing media use oil absorbents (e.g., adsorbents and / or oil adsorbents) filter media configured to capture oil particles or oil vapors before they reach the membrane. However, such vents have a relatively short lifespan because the medium becomes clogged as oil particles accumulate, shortening the vent's lifespan. Furthermore, because adsorbent filter media wick these oil particles, oil can contaminate the membrane relatively quickly. Summary of the Invention

[0004] Some embodiments of the technology disclosed herein relate to a vent assembly. The vent housing has a first end and a second end. The vent housing defines a mounting structure and an airflow path extending from the mounting structure to the environment outside the vent housing. A plurality of filter media sections are arranged in series along this airflow path. The plurality of sections are configured to span the airflow path. The plurality of filter media sections include efficiency sections and spacer sections, which alternate in series. Each spacer section has a flow resistance up to 80% of the flow resistance of each efficiency section.

[0005] In some such embodiments, the plurality of sections comprises at least five sections. Alternatively or alternatively, the vent assembly comprises at least seven sections per 100 mm of tandem thickness. Alternatively or alternatively, each efficiency section has a flow resistance ratio from 25.5 Pa / (cm / s) / cm to 125 Pa / (cm / s) / cm. Alternatively or alternatively, each spacer section has a flow resistance ratio up to 23.6 Pa / (cm / s) / cm. Alternatively or alternatively, at 10.34 kPa, the combined thickness of the efficiency sections is 70% to 95% of the total tandem thickness. Alternatively or alternatively, the tandem has a total particle capture efficiency of at least 97%. Alternatively or alternatively, each efficiency section has a particle capture efficiency greater than 75%. Alternatively or alternatively, at 10.34 kPa, each section has a density from 0.10 g / cm³. 3 Up to 0.4 g / cm 3 Alternatively or alternatively, the plurality of segments include adhesive fibers and glass fibers. Alternatively or alternatively, the vent assembly has a membrane disposed within the vent housing across an airflow path between the plurality of segments and the external environment. Alternatively or alternatively, the vent assembly has an adsorbent layer disposed across an airflow path between the membrane and the plurality of segments. Alternatively or alternatively, at least one spacer layer includes an adsorbent. Alternatively or alternatively, each spacer segment has a Fraser permeability of at least 200 ft. 3 / min / ft 2 .

[0006] Some embodiments of the technology disclosed herein relate to a vent assembly having a vent housing with a first end and a second end. The vent housing defines a mounting structure and an airflow path extending from the mounting structure to the environment outside the vent housing. A plurality of filter media segments are arranged in series along this airflow path. These segments are configured to span the airflow path. The plurality of filter media segments include efficiency segments and spacer segments, which alternate in the series. The series has a total particle capture efficiency of at least 97%. Each efficiency segment has a particle capture efficiency of at least 80%.

[0007] In some such embodiments, the plurality of sections comprises at least five sections. Alternatively or alternatively, the vent assembly comprises at least seven sections per 100 mm of tandem thickness. Alternatively or alternatively, each efficiency section has a flow resistance ratio from 25.5 Pa / (cm / s) / cm to 125 Pa / (cm / s) / cm. Alternatively or alternatively, each spacer section has a flow resistance ratio up to 23.6 Pa / (cm / s) / cm. Alternatively or alternatively, at 10.34 kPa, the combined thickness of the efficiency sections is 70% to 95% of the total tandem thickness. Alternatively or alternatively, each spacer section has a flow resistance ratio up to 80% of the flow resistance ratio of each efficiency section. Alternatively or alternatively, each efficiency section has a particle capture efficiency of at least 85%. Alternatively or alternatively, at 10.34 kPa, each section has a density from 0.10 g / cm³. 3 Up to 0.4 g / cm 3 Alternatively or alternatively, the plurality of segments include adhesive fibers and glass fibers. Alternatively or alternatively, a membrane is provided in the vent housing across the airflow path between the plurality of segments and the external environment. Alternatively or alternatively, an adsorbent layer is provided across the airflow path between the membrane and the plurality of segments. Alternatively or alternatively, at least one spacer layer includes an adsorbent. Alternatively or alternatively, each spacer segment has a Fraser permeability of at least 200 ft. 3 / min / ft 2 .

[0008] The foregoing summary is not intended to describe every embodiment or every implementation. Rather, a more complete understanding of the illustrative embodiments will become clear and understood by referring to the following detailed description and claims in conjunction with the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a perspective view of an exemplary filter component consistent with this disclosure.

[0010] Figure 2 Is with Figure 1 An exemplary cross-sectional view consistent with the exemplary filter component.

[0011] Figure 3 It is a graph that depicts the test results of an exemplary vent assembly configuration.

[0012] Figure 4 It is a graph depicting test results for an exemplary vent assembly configuration consistent with this disclosure.

[0013] Figure 5It is a graph depicting the test results of yet another exemplary vent assembly configuration consistent with this disclosure.

[0014] Figure 6 It is a graph that depicts the comparative test results of the vent assembly.

[0015] Figure 7 It is a graph that depicts the results of another comparative test of the vent assembly.

[0016] Figure 8 It is another graph that depicts the results of additional comparative tests on the vent assembly.

[0017] Figure 9 It is another graph that depicts the results of additional comparative tests on the vent assembly.

[0018] Figure 10 This is a schematic diagram of an exemplary test configuration.

[0019] Figure 11 It is a graph that shows the results based on... Figure 10 The description shows the pressure difference of the exemplary vent assembly tested over time.

[0020] Figure 12 It is a graph that shows the pressure difference of an exemplary vent assembly over time.

[0021] Figure 13 It is used for collection Figure 12 A schematic diagram of an exemplary test configuration reflecting the data.

[0022] Figure 14 This is an exemplary flowchart that depicts a method consistent with this disclosure.

[0023] The present technology can be more fully understood and appreciated in light of the following detailed description of various embodiments in conjunction with the accompanying drawings.

[0024] The accompanying drawings are presented primarily for clarity and are therefore not necessarily drawn to scale. Furthermore, various structures / components, including but not limited to fasteners, electrical components (wiring, cables, etc.), etc., may be shown schematically or removed from some or all views to better illustrate aspects of the depicted embodiments, or where including such structures / components is not necessary for understanding the various exemplary embodiments described herein. However, the absence of such structures / components shown / described in a particular figure should not be construed as limiting the scope of the various embodiments in any way. Detailed Implementation

[0025] Figure 1This is a perspective view of the vent assembly 100, which is consistent with the technology disclosed herein, and Figure 2 yes Figure 1 A cross-sectional view of the vent assembly 100. The vent assembly 100 generally has a vent housing 110 that defines a first end 102, a second end 104, a mounting structure 120, and an airflow path 150 extending from the mounting structure 120 to the outside of the vent housing 110. The vent assembly 100 generally has a plurality of filter media sections 180 disposed within the vent housing 110.

[0026] The vent assembly 100 is generally configured such that the housing 200 on which the vent assembly is mounted (e.g., Figure 2 The vent assembly 100 (as depicted) allows ventilation while preventing dust, fluids, and other contaminants from entering the vent housing 200. In an embodiment, the vent assembly 100 is designed to achieve IP69K intrusion protection, meaning that after installation, the vent assembly 100 protects the vent housing 200 from close-range, high-pressure, high-temperature sprays. In an embodiment, the vent assembly 100 is configured to meet various intrusion protection industry standards. The vent assembly 100 is also configured to prevent oil aerosols from the vent housing 200 from flowing to the second end 104 of the vent assembly 100.

[0027] The vent housing 110 is generally configured to define an airflow path between the enclosure 200 to which the vent housing 110 is attached and the external environment, thereby eliminating or reducing the pressure difference between the enclosure 200 and the external environment. The vent housing 110 can be any suitable material, including plastic or metal. In some embodiments, the vent housing 110 can be made of one or more materials, examples of which include nylon, polyamide, glass-filled polyamide, polybutylene terephthalate, high-density polyethylene, and / or polypropylene.

[0028] In various embodiments, the housing 200 (with the vent housing 110 configured as the associated housing) is generally configured to contain oil. The housing 200 can also be configured to contain moving parts, such as gears. The housing 200 can be used in a wide variety of applications, such as drivetrains, gearboxes, power transmission units, axle components, etc. Such applications are particularly found in industries such as automotive, manufacturing, and energy production. Those skilled in the art will understand that this technology has broad applicability in a wide range of technical fields.

[0029] The vent housing 110 defines a mounting structure 120 configured to engage with the housing 200. The mounting structure 120 is defined facing a first end 102 of the vent housing 110. In the current example, the mounting structure 120 defines a circumferential thread 122 configured to engage with the housing 200 itself, for example, via a mating thread defined by the housing 200. Alternatively, the mounting structure 120 may be configured to engage with an intermediate component configured to connect the vent housing 110 to the housing 200. Other methods may be used to directly or indirectly engage the vent assembly 100 with the housing 200, as will be understood. The mounting structure 120 may have alternative configurations for a sealably engaging connection to the housing 200. In some embodiments, as an example, the mounting structure 120 is a snap-fit, a hose barb, a beaded interface, a bayonet connector, a fastener opening configured to receive a fastener, or configured to be adhered to the surface of the housing itself (or an intermediate component connected to the housing) by means of adhesive or welding.

[0030] In various embodiments, the mounting structure 120 includes an O-ring or washer 124 ( Figure 2 (Clearly visible in the image) to hermetically connect the vent assembly 100 to the housing 200. The O-ring is configured to be positioned between the mounting structure 120 and the housing 200 around an opening 202 in the housing 200. In some embodiments, the O-ring contacts the housing 200 and the mounting structure 120 to form an hermetically tight seal. In some embodiments, the mounting structure 120 of the vent assembly 100 may be configured to directly receive the opening 202 defined by the housing 200. In some embodiments, the O-ring 124 may be configured to be compressibly and hermetically disposed between the mounting structure 120 and the housing 200.

[0031] Airflow path 150 extends from mounting structure 120 through the plurality of filter media sections 180 to reach the external environment. Vent housing 110 defines a peripheral opening 140 through which airflow path 150 extends to the external environment. Vent assembly 100 has vent cover 130 attached to vent housing 110.

[0032] The plurality of filter media sections 180 are arranged in the vent housing 110 to span the airflow path 150. The plurality of filter media sections 180 are generally configured to capture oil aerosols and prevent their flow. The plurality of filter media sections 180 will be discussed in more detail below. membrane

[0033] In some embodiments, the vent housing 110 is coupled with a membrane 160 that spans the airflow path 150. However, it should be noted that the membrane 160 may be omitted in various embodiments. When the membrane 160 is included, it is generally configured to act as a barrier against external fluids and dust contaminants from the housing 200, while allowing air exchange between the housing 200 and the external environment (e.g., the atmosphere). In various embodiments, the membrane 160 is coupled to a membrane receiving surface 112 defined by the vent housing 110. In one example, the membrane 160 is pleated to increase airflow.

[0034] The membrane 160 is positioned toward the second end 104, while the plurality of filter media sections 180 are positioned toward the first end 102. The membrane 160 is positioned along the airflow path 150 between the external environment and the plurality of filter media sections 180.

[0035] Various types of materials are suitable for use as membrane 160. Generally, membrane 160 is a microporous material, where the term "microporous" is intended to mean that the average pore size defined by the material is between about 0.001 micrometers and about 5.0 micrometers. Membrane 160 has an overall porosity of less than about 50% and a density greater than about 50%. In various embodiments, membrane 160 has multiple nodes interconnected by fibrils. In several embodiments, membrane 160 is an expanded polytetrafluoroethylene (ePTFE) membrane. As other examples, membrane 160 may also be composed of polyamide, polyethylene terephthalate, acrylic resins, polyethersulfone, and / or polyethylene. The water inlet pressure (WEP) of membrane 160 can be at least 5 psi.

[0036] In some embodiments, membrane 160 is a laminate. For example, membrane 160 may be a Tetratex™ laminate grade from Donaldson, Inc., Inc., headquartered in Minneapolis, Minnesota.

[0037] In several embodiments, membrane 160 is oleophobic. Membrane 160 may have an oleophobic treatment. In one particular embodiment, membrane 160 has an oleophobicity rating of 6, 7, or 8 (based on AATCC standard 118-1992 and ISO 14419). However, it should be noted that membrane 160 may be omitted in various embodiments. Interval area

[0038] In the current example, the vent assembly 100 has a spacer region 170 defined by the vent assembly 100 between the plurality of filter media segments 180 and the membrane 160. The spacer region 170 of the vent assembly 100 is generally configured to prevent oil from the housing 200 from contacting the membrane 160. Specifically, the spacer region 170 may be configured to prevent oil from being wicked toward the membrane 160. The spacer region 170 may also be configured to prevent the plurality of filter media segments 180 from contacting the membrane 160. The spacer region 170 may be a physical barrier between the plurality of filter media segments 180 and the membrane 160. In at least one example, the spacer region 170 may be a physical barrier configured to house the plurality of filter media segments within the vent housing 110.

[0039] In a variety of embodiments (including) Figure 2 In the embodiment depicted herein, the spacer region 170 is at least partially defined by a media spacer 172. The media spacer 172 is disposed within the vent housing 110, between the plurality of filter media segments 180 and the membrane 160. The spacer region 170 is also defined by a physical gap 174 between the media spacer 172 and the membrane 160. In an alternative embodiment, the spacer region 170 has no media spacer, but is simply a physical gap between the plurality of filter media segments and the membrane. Multiple filter media sections

[0040] The plurality of filter media sections 180 are generally configured to capture oil aerosols as they flow from the casing 200 through the airflow path 150 through the vent assembly 100. Advantageously, this configuration prevents oil deposition on the membrane 160 (where the membrane 160 is present), which could lead to pore blockage in the membrane 160 and consequently shorten the vent life. The plurality of filter media sections 180 are also configured to retain the captured oil aerosols while maintaining the permeability of the plurality of filter media sections 180 to achieve their effective service life. In various embodiments, the plurality of filter media sections 180 are designed to maximize the amount of oil aerosols that can be captured, thereby providing a relative extension of the effective service life of the plurality of filter media sections 180. configuration

[0041] The plurality of filter media sections 180 are generally arranged in series (e.g., in a stacked configuration) along the airflow path 150, meaning that airflow along the airflow path 150 is configured to flow sequentially through each of the filter media sections 180. In various embodiments, the plurality of filter media sections 180 include efficiency sections 182 and spacer sections 184. Efficiency sections 182 are generally configured to capture and store oil aerosols, while spacer sections 184 are configured to define spaces between efficiency sections 182. Spacer sections 184 are generally configured such that they do not capture and store oil aerosols. In various examples, spacer sections 184 are configured to interrupt the flow of captured oil from a first efficiency section 182 located on one side of the spacer section 184 to a second efficiency section 182 located on the opposite side of the spacer section 184.

[0042] Efficiency segments 182 and spacer segments 184 generally alternate in a series. In some embodiments, efficiency segments 182 and spacer segments 184 alternate regularly in a predictable pattern in a series. In other embodiments, the alternation between efficiency segments 182 and spacer segments 184 is irregular. For example, the thickness of one or more efficiency segments 182 may not be equal to the thickness of one or more other efficiency segments 182, or the thickness of one or more spacer segments 184 may not be equal to the thickness of one or more other spacer segments 184. In various embodiments, two efficiency segments 182 are adjacent to each spacer segment 184 on opposite sides. In some other embodiments, one or more additional intermediate segments may be provided between efficiency segments 182 and spacer segments 184.

[0043] In some embodiments, the vent assembly 100 has at least 7, 9, or 10 segments per 100 mm of total series thickness T, where "series thickness" is the total distance across all of the plurality of filter media segments 180. In some embodiments, the vent assembly 100 has at least 20, 30, or 40 segments per 100 mm of total series thickness T. It should be noted that in embodiments where the efficiency segment 182 and the spacer segment 184 are arranged in a stacked manner, the total series thickness is the height of the stack. In an exemplary embodiment of the prior art, the total series thickness T is 11 mm to 15 mm, 12 mm to 13 mm, or about 12.5 mm. However, other series thicknesses T are also contemplated, such as 20 mm to 80 mm, 50 mm to 100 mm, or 75 mm to 125 mm.

[0044] Efficiency section 182 can be differentiated from spacer section 184, at least in terms of flow resistance. As used herein, “flow resistance” characterizes the resistance of material per unit thickness to airflow at an air velocity of 1 cm / s under atmospheric temperature and pressure. Generally, efficiency section 182 has a higher flow resistance than spacer section 184. Each spacer section 184 has a flow resistance up to 80% of the flow resistance of each efficiency section 182. The flow resistance of each efficiency section 182 (and virtually all efficiency sections) can be greater than 24.0 Pa / (cm / s) / cm, 24.5 Pa / (cm / s) / cm, or 25.0 Pa / (cm / s) / cm. In some embodiments, the flow resistance of each efficiency section 182 can be less than 95 Pa / (cm / s) / cm, 90 Pa / (cm / s) / cm, or 89 Pa / (cm / s) / cm. However, the maximum flow resistance of the efficiency sections is not particularly limited, but can be based on the operating conditions and / or desired performance of the vent assembly 100. In some embodiments, the flow resistance of each efficiency section 182 ranges from 25.5 Pa / (cm / s) / cm to 88.6 Pa / (cm / s) / cm. The flow resistance of each spacer section 184 (and virtually all spacer sections) can be less than 26 Pa / (cm / s) / cm, 25 Pa / (cm / s) / cm, or 24 Pa / (cm / s) / cm. There is no particular limitation on the lower limit of the flow resistance of the spacer section 184. In some specific exemplary vent assemblies tested, the flow resistance of the spacer section 184 is greater than 9 Pa / (cm / s) / cm, 10 Pa / (cm / s) / cm, or 11 Pa / (cm / s) / cm. In various embodiments, the flow resistivity of the spacer section ranges from 11.8 Pa / (cm / s) / cm to 23.6 Pa / (cm / s) / cm.

[0045] Efficiency section 182 and spacer section 184 can have a wide variety of different configurations and combinations thereof. In some embodiments, one or more of the plurality of filter media sections 180 are one or more layers of filter material arranged in series (e.g., in a stacked configuration). In some embodiments, each of the plurality of filter media sections 180 is one or more layers of filter material arranged in series. In various embodiments these layers may be unbonded, although in some other embodiments these layers may be bonded. In some embodiments, one or more of the plurality of filter media sections 180 are fiber blocks. In some embodiments, at least one of the plurality of filter media sections 180 includes an adsorbent, wherein "adsorbent" herein refers to, for example, activated carbon, silica gel, molecular sieves, etc.

[0046] In various embodiments, each efficiency segment 182 has a higher particle capture efficiency than each spacer segment 184. In some embodiments, each efficiency segment has a particle capture efficiency greater than 70%, 75%, or 80%, wherein the particle capture efficiency is evaluated using the High Efficiency Flat Sheet (HEFS) TSI Automated Filter Tester Model 8127 test platform (TSI Corporation, Shoreview, Minnesota)—this test platform is used to measure particle capture efficiency by challenging media samples with 0.3 µm oil (bis(2-ethylhexyl) sebacic acid, Sigma-Aldrich) drops (aerosol) at a flow rate of 14.7 liters per minute (L / min) to a diameter of 4 inches or larger. This platform is used to test up to four media layers in a single run. The TSI CertiTest Model 8127 Automated Filter Tester is designed to test filters, respirator cartridges, and filter media according to the latest U.S. government and industry standards and conforms to 42 CFR § 84 (June 8, 1995).

[0047] Calculate the penetration, which is the ratio of the number of 0.3 µm particles measured downstream of the sample to the number of 0.3 µm particles measured upstream of the sample. After calculating the penetration of a single layer, calculate the total penetration value using the formula below. The number of layers can then be adjusted to achieve the target penetration. Where n is the number of dielectric layers and the penetration is... 总 It refers to the penetration of the stacked layers, and the penetration... 单个层 This refers to the penetration of a layer, where a layer can be a single segment of the filter medium, multiple segments of the filter medium, or a portion of a segment of the filter medium. Particle capture efficiency (whether it's the particle capture efficiency of the total number of layers or the particle capture efficiency of a single layer) is the percentage of particles that do not penetrate the medium, or 100 minus penetration. 100. In various embodiments, the particle capture efficiency exhibited by the spacer section is too low to be evaluated with relatively high certainty by the HEFS TSI automated filter tester platform.

[0048] In various embodiments, each efficiency segment 182 has a higher density than each spacer segment 184. In some embodiments, the density of each efficiency segment 182 is less than or equal to the density of each spacer segment 184. In some embodiments, the surface area per unit volume of each efficiency segment 182 is greater than the surface area per unit volume of each spacer segment 184. In some embodiments, each efficiency segment 182 has a lower Fraser permeability than each spacer segment 184. In some embodiments, the Fraser permeability of each spacer segment ranges from 200 ft.3 / min / ft 2 up to 450 ft 3 / min / ft 2 Or from 213 ft 3 / min / ft 2 up to 425 ft 3 / min / ft 2 In some embodiments, the Fraser permeability of each efficiency band ranges from 8 ft. 3 / min / ft 2 up to 17 ft 3 / min / ft 2 Or from 9.5 ft 3 / min / ft 2 up to 15 ft 3 / min / ft 2 In some embodiments, the Fraser permeability of each efficiency section does not exceed 20 ft. 3 / min / ft 2 30 ft 3 / min / ft 2 or 40 ft 3 / min / ft 2 .

[0049] In some embodiments, each efficiency section 182 has a higher net pressure drop than each spacer section 184, wherein the net pressure drop is defined as the pressure difference across a particular filter media section before particles are captured. The net pressure drop (dP) is calculated based on known variables of the material, including flow resistivity, material thickness at 1.5 psi (10.34 kPa), and a flow rate of 9.1 cm / s. In some embodiments, the net pressure drop of each efficiency section ranges from 130 Pa to 250 Pa or from 150 Pa to 235 Pa. In some embodiments, the net pressure drop of each spacer section ranges from 2 Pa to 13 Pa or from 4 Pa ​​to 11 Pa.

[0050] Generally, the multiple filter media sections 180 are configured to capture oil aerosols and therefore possess a relatively high particle capture efficiency to achieve this function. The total particle capture efficiency of the multiple filter media sections 180 can be at least 90%, at least 95%, and / or at least 99%, where "total particle capture efficiency" is used herein to refer to the percentage of particles that did not penetrate the multiple filter media sections 180, calculated using the corresponding method on the HEFS TSI 8127 automatic filter tester platform discussed above. This calculation ignores any contribution to the efficiency of the spacer sections.

[0051] The net pressure drop of these multiple filter media sections 180 can be less than 1.2 psi, 1.0 psi, or even 0.8 psi.

[0052] As described in more detail below, it has been found that alternating between the spacer section and the efficiency section increases the volume of oil that the efficiency section can hold. Test Results

[0053] Figures 3 to 5 These are test results reflecting the oil saturation (by volume) in each of the multiple filter media sections, where the overall performance was tested. Figures 1 to 2 Consistent vent assembly, wherein the vent assembly being tested is specified here. Figures 1 to 2 The differences between the vent assemblies. The housing of each vent assembly is a stainless steel syringe filter housing. Thus, with... Figures 1 to 2 Unlike other vent assemblies, this syringe filter housing has an upstream side and a downstream side, with an inlet on the upstream side and an outlet on the downstream side. The outlet is open to the atmosphere. The internal depth of the syringe filter housing from top to bottom is 19.33 mm. The syringe filter housing contains the following items from upstream to downstream between the inlet and outlet: (1) two Buner rubber gaskets; (2) multiple filter media sections with a nominal thickness of 16.5 mm when measured at a pressure of 10.34 kPa; (3) one Buner rubber gasket; and a membrane layer.

[0054] Compressed air pressurized at 6.9 bar was supplied to a Topas ATM220 aerosol generator (Topas GmbH, Germany) filled with off-the-shelf automatic transmission fluid. The pressure was reduced to 400 mbar using an integrated pressure regulator, creating a constant aerosol flow rate. This flow was directed into an aerosol source chamber—which has a first port and a second port. The first port was attached to the inlet of the syringe filter housing. A pressure gauge was connected to the second port to measure the pressure difference relative to ambient pressure. This pressure was sampled every 10 seconds. All tests were run at a constant flow rate under ambient conditions until a terminal pressure drop of 140 mbar was reached.

[0055] To evaluate the vent's response to oil load, the vent assembly's inlet was connected to the aerosol source chamber, and the pressure was sensed and recorded using the pressure gauge's automatic recording feature. The next step was to redirect the compressed air supply to the aerosol generator. The platform was monitored to confirm correct operation until the terminal pressure drop. The vent assembly was then removed from the platform, and the final weight of each section was measured.

[0056] To calculate the saturation of the medium, the porosity (void volume) is first determined using a mass method. For this, the weight, area, and thickness of each section of the filter medium are measured at 10.34 kPa. The porosity is then calculated using the following equation: Where ε is the porosity (void volume), M is the mass of the segment, ρ is the average fiber density in the segment, and V is the total volume of the segment. These multiple filter media segments are then inserted into the filter holder and loaded with oil until the terminal pressure drop is reached using the equipment listed above. The multiple filter media segments are then removed from the syringe filter holder, and each segment is weighed again. The weight difference is the increase in oil content, and this value is divided by the density of the oil used, 0.83 g / cm³. 3 The total oil volume is obtained. This oil volume is then divided by the initial medium porosity (void volume) to obtain the saturation percentage at the terminal pressure drop.

[0057] Figure 3 These are test data reflecting oil saturation (by volume) in each of several efficiency bands, where... Figures 1 to 2 A consistent vent assembly has an efficiency section stack arranged across the airflow path of the vent body. The efficiency sections are arranged in series along the airflow path of the vent body. Each efficiency section is identical and has multiple (specifically 11) discrete and identical layers of filter media. Each layer has a thickness of 0.3 mm at 10.34 kPa. No spacer sections are used between the efficiency sections, thus these multiple filter media sections are entirely efficiency sections. The x-axis reflects the position of each efficiency section along the thickness of the series stack, where the "0 mm" position is the surface of the efficiency section closest to the first end of the vent body. The y-axis reflects the percentage of oil saturation of the efficiency sections relative to the usable volume defined by the efficiency sections. In an exemplary test, the efficiency sections have a flow resistance of 57.0 Pa / (cm / s) / cm.

[0058] like Figure 3 As can be seen, the first and last efficiency zones have the highest oil saturation, which is just below 50% of the volume of the efficiency zone. The middle efficiency zone contains about 40% oil (by volume).

[0059] Figure 4 Comparative data for vent assemblies consistent with the technology disclosed herein are shown. More specifically, along the airflow path of the vent body consistent with the above description, efficiency sections and spacer sections alternate in series. Each of the efficiency sections and spacer sections extends across the airflow path. These efficiency sections are consistent with those described above. Figure 3 The efficiency sections are identical, except that each efficiency section has nine discrete and identical layers of efficiency filter material. Spacer sections are positioned between each pair of successive efficiency sections. Each spacer section is a layer of spacer material with a thickness of 0.48 mm. The flow resistance of the spacer sections (and therefore the spacer material) is 11.8 Pa / (cm / s) / cm.

[0060] Surprisingly, spacer sections are introduced between efficiency sections (such as...). Figure 4 The oil saturation in each efficiency segment (as in the exemplary vent assembly tested) compared to the efficiency segment without spacers between efficiency segments (e.g., reference) Figure 3 The test results described in the example are higher (as depicted in the example). Figure 4 Each efficiency range maintains at least approximately 60% oil (by volume), and compared to the reference... Figure 3 Each efficiency section of the described vent assembly retains approximately 10% to 30% more oil (by volume). Therefore, separating the efficiency sections with spacer sections improves the oil retention capacity of the efficiency sections.

[0061] Figure 5 Further comparative data for another vent assembly consistent with the technology disclosed herein are shown. More specifically, along the airflow path of the vent body consistent with the description above, efficiency sections and spacer sections alternate in series. Each of the efficiency sections and spacer sections extends across the airflow path. Spacer sections are positioned between each pair of efficiency sections, and each spacer section is consistent with the reference above. Figure 4 The spacer sections described are identical. However, the flow resistivity (88.6 Pa / (cm / s) / cm) of the efficiency sections (and therefore each efficiency filter material layer) is higher than that of the reference section. Figure 4 The efficiency sections described have high flow resistance. Each efficiency section consists of four discrete and identical filter material layers, each with a thickness of 0.72 mm at 10.34 kPa.

[0062] Figure 5 Each efficiency segment, except for one, maintains over 90% oil (by volume), while the last efficiency segment maintains approximately 55% oil (by volume). It should be noted that the data corresponding to the third and fourth efficiency segments may be due to one or both of the following: (1) the efficiency segment expands and therefore holds a higher volume of oil than the unexpanded segment; and (2) mathematical errors result in data reflecting an oil saturation exceeding 100% (by volume). Overall, with Figure 5 Compared to consistent vent assemblies Figure 4A consistent vent assembly retains a higher oil volume.

[0063] Figure 6 Additional test results are described, which will be compared with... Figure 5 The vent assembly described herein was compared with other vent assemblies that use the same filter material layer for each efficiency segment and the same spacer material layer for each spacer segment. In each vent assembly, the efficiency segments and spacer segments alternate along the series in a consistent pattern. However, the combined thickness of the efficiency segments (relative to the total series thickness T) differs in each vent assembly, as reflected on the x-axis. The mass of oil held by these multiple filter media segments at 75 mbar (pressure drop across the vent assembly) is reflected on the y-axis.

[0064] The test setup and test conditions are the same as those mentioned above. Figure 5 The described test settings and conditions are consistent. The test will continue until a specific time (T) is reached. 终端 The terminal pressure was reached at 140 mbar, and the difference in mass before and after the terminal pressure was reached was determined at T. 终端 The oil mass (M) maintained by these multiple filter media sections 终端 Because the supply of aerosol guided through the vent assembly during the test was carried out at a constant rate and for a time duration of 75 mbar (T). 75毫巴 ) is a known variable (recorded by the test equipment), therefore it is used Figure 6 The following equation, as described in the figure, is used to calculate the mass of oil (M) held by the multiple filter media sections at 75 mbar. 75毫巴 ):

[0065] It is worth noting that the relatively high combined thickness of the efficiency section (relative to the total series thickness T) results in a significant increase in the quality of the oil maintained.

[0066] Based on this data, it appears that increasing the percentage of the total thickness defined by efficiency section 182 in the series thickness T would increase the amount of oil that can be collected through vent assembly 100. However, if the percentage of the total thickness defined by efficiency section 182 in the series thickness T is too high and therefore the distance defined by spacer section 184 between efficiency sections 182 is too small, the oil retention capacity of efficiency section 182 is expected to decrease and approach the oil retention capacity of multiple filter media sections without spacer sections (e.g., reference...). Figure 3(Described). In various embodiments, the total thickness of the efficiency sections 182 is at least 70% or 75% of the total series thickness T. Generally, the combined thickness of the efficiency sections 182 will be less than 99%, 97%, or 95% of the total series thickness T. In some embodiments, the combined thickness of the efficiency sections 182 is 77% to 90% of the total series thickness T. Thickness was measured at 10.34 kPa.

[0067] Figure 7 The collected data are provided, reflecting a comparison between the total oil load of the multiple filter media sections of the vent assembly at 75 mbar and the particle capture efficiency per efficiency section for 0.4 µm particles. Each efficiency section and spacer section within each tested vent assembly is identical, but various efficiency sections and spacer sections were tested on different vent assemblies. Test setup and conditions are the same as described above. Figures 3 to 6 The described test settings and test conditions are consistent. (See above reference.) Figure 6 The oil load is calculated at 75 mbar as described. The efficiency range with a particulate capture efficiency of at least 80% appears to exhibit a relatively higher oil load compared to the efficiency range with a lower particulate capture efficiency. Furthermore, as the particulate capture efficiency increases beyond 93%, the oil load in these multiple filter media ranges can exhibit a relatively lower oil load.

[0068] Figure 8 The collected data are provided, reflecting a comparison of total oil load versus flow resistance efficiency across multiple filter media sections of the vent assembly at 75 mbar. Each efficiency section and spacer section within each individually tested vent assembly is identical; however, various efficiency sections and spacer sections were tested on different vent assemblies. Test setup and conditions are the same as described above. Figure 7 The described test settings and test conditions are consistent. (See above reference.) Figure 6 The oil loading capacity is calculated at 75 mbar as described. The efficiency range with a flow resistance greater than 65 Pa / (cm / s) / cm appears to exhibit relatively higher oil retention capacity compared to the efficiency range with lower flow resistance. The efficiency range with a flow resistance less than approximately 125 Pa / (cm / s) / cm appears to exhibit relatively higher oil retention capacity compared to the efficiency range with higher flow resistance. In the current test, a flow resistance of approximately 89.0 Pa / (cm / s) / cm appears to maximize the oil retention capacity of the efficiency range for the specific configuration tested based on the tested flow resistance.

[0069] Figure 9The collected data are provided, reflecting a comparison of the total oil load across multiple filter media sections of the vent assembly at 75 mbar with the number of discrete efficiency sections. Each efficiency section and spacer section within each individually tested vent assembly is identical; however, various efficiency sections and spacer sections were tested on different vent assemblies. Test setup and conditions are the same as described above. Figures 3 to 7 The described test setup and conditions are consistent. The multiple filter media sections in each tested vent assembly have a series thickness of 12.5 mm. (See above reference.) Figure 6 The oil load is calculated at 75 mbar. This data indicates that the oil load increases relatively when there are more than 5 efficiency segments in a 12.5 mm stack, which is equivalent to more than 40 efficiency segments per 100 mm of tandem thickness. The oil load also increases relatively when there are fewer than 17 efficiency segments in a 12.5 mm stack, which is equivalent to fewer than 136 efficiency segments per 100 mm of tandem thickness.

[0070] based on Figure 9 The results might suggest 9 to 13 efficiency segments within a 12.5 mm stack, or 72 to 104 efficiency segments per 100 mm tandem thickness. However, it should be noted that these test results are merely one example of using the same material layers to form both the efficiency segments and the spacer segments. Using different materials and different combinations of materials for both spacer and efficiency segments could result in varying numbers of discrete efficiency segments achieving relatively high oil retention. Efficiency range

[0071] return Figure 1 and Figure 2Efficiency sections 182 can be made of a wide variety of materials and combinations thereof. In various embodiments, one or more of efficiency sections 182 are nonwoven filter media. One or more of efficiency sections 182 can be made of polymer fibers. As an example, one or more of efficiency sections 182 can be made of fibers such as polypropylene, polyethylene, PET, nylon, and cellulose fibers. One or more of efficiency sections 182 can be made of fibers and adhesive materials (such as adhesive resins or adhesive fibers). For example, one or more efficiency sections 182 can have adhesive fibers, such as thermoplastic fibers and / or bicomponent fibers. Bicomponent fibers can be made of two different polymers (such as two different polyesters). In some embodiments, one or more efficiency sections 182 can have glass fibers. In at least some embodiments, the glass fibers are microfibers. Generally, one or more efficiency sections 182 are substantially free of adhesive materials, wherein the term "adhesive material" is defined herein as excluding fibers, such as adhesive fibers, bicomponent fibers, or other fibers. In a wide variety of embodiments, one or more efficiency sections 182 of the vent assembly 100 contain oil coalescing filter media. In some embodiments, at least one of the plurality of efficiency segments 182 includes an adsorbent material.

[0072] One or more efficiency segments 182 of the plurality of filter media segments 180 of the vent assembly 100 may be multiple filter media layers arranged in series. In some embodiments, one or more filter media layers are made of synthetic fibers. A majority of these layers may be arranged such that each flow surface of each filter media layer is in direct contact with the flow surface of the adjacent filter media layer, and each flow surface extends across the airflow path 150. The term "flow surface" is used to refer to each surface of the filter media configured to face the direction of airflow through the airflow path 150. In various embodiments, the airflow path 150 extends in an axial direction, and each filter media layer is perpendicular to the axial direction; however, this configuration is not necessarily limited. In some other embodiments, one or more efficiency segments 182 are fiber blocks. Furthermore, each efficiency segment need not be identical.

[0073] In various embodiments, the efficiency of each efficiency segment 182 and the total number of efficiency segments 182 are configured to achieve a target total particle capture efficiency for the plurality of filter media segments 180. Spacer section

[0074] Spacer segments 184 can be made of a wide variety of materials and combinations thereof. In some embodiments, one or more spacer segments 184 are made of fibrous material. The fibrous material can be nonwoven or woven. The fibers can include polymer fibers and nonpolymer fibers. One or more spacer segments 184 can have an adhesive material, such as an adhesive resin or adhesive fibers. For example, one or more spacer segments 184 can have bicomponent fibers. Bicomponent fibers can be made of two different polymers, such as two different polyesters. In some embodiments, one or more spacer segments 184 can have glass fibers, such as glass microfibers. In a variety of embodiments, one or more spacer segments 184 of the vent assembly 100 contain coalescing filter media. In some embodiments, one or more spacer segments 184 have cellulose fibers. In some examples, one or more spacer segments 184 are substantially free of adhesive material. In some embodiments, one or more spacer segments 184 do have an adhesive material, such as an adhesive resin, distributed between the fibers. In some embodiments, at least one of the plurality of spacer segments 184 includes an adsorbent. In some other embodiments, an adsorbent layer is provided across the airflow path 150 between the membrane 160 and the plurality of filter media sections 180. In some examples, the spacer layer will be made of metal fibers. In other embodiments, the fibers will be woven into a patterned structure.

[0075] It should be noted that the spacer segments 184 do not need to be filter materials or fibrous media. In some embodiments, one or more spacer segments 184 are lattice or screen structures made of metal or polymer materials. In some embodiments, one or more spacer segments 184 comprise a coarse cloth material. In some embodiments, one or more of the spacer segments 184 do not exhibit particle capture efficiency with respect to oil aerosols. However, in some such embodiments, one or more of the spacer segments 184 can capture relatively large particles.

[0076] It has been found that, in embodiments where the vent housing is heated and oil vapor is generated within the housing, using an adsorbent material as a spacer layer can advantageously improve the lifespan of the vent assembly. Figure 10This is a schematic test setup for testing multiple filter media sections with various configurations. A housing 310 contains a volume of oil 312, and a heating element 320 heats the oil and maintains it at a constant temperature, which is monitored by a temperature sensor 330. A flow meter 350 directs air at a constant flow rate from an air supply device 340 into the inlet 314 of the housing 310, generating an airflow across the oil 312 to form an airflow jet containing oil vapor. An outlet 316 of the housing 310 is connected to a vent assembly 100, and the vapor-containing airflow flows into the first end 102 of the vent assembly 100, through the multiple filter media sections and the membrane, and through the second end 104 of the vent assembly 100 to the external environment. A pressure sensor 360 measures the pressure difference across the vent assembly 100 at constant intervals until a terminal pressure difference is achieved.

[0077] Figure 11 The test results are described below. Each vent assembly tested has the same vent housing and the same membrane disposed on the vent housing. The reference vent assembly does not have spacer sections within the multiple filter media sections, but rather is a series of identical filter media (referred to as the "reference filter media") layers, the total thickness of which is sufficient to fill the usable volume of the vent housing. The multiple filter media sections have a flow resistance of 57.0 Pa / (cm / s) / cm. The total particle capture efficiency of the multiple filter media sections is greater than 97%. The carbon media #1 vent assembly has multiple filter media sections including efficiency sections and spacer sections. Each efficiency section is four discrete and identical reference filter media layers. A spacer section is disposed between each pair of successive efficiency sections in the series. Each spacer section is a single adsorbent carbon filter material layer—a coarse cloth layer laminated on each side of the carbon media layer. The spacer section has a nominal Fraser permeability of 245 ft. 3 / min / ft 2 Furthermore, it possesses a flow resistance of 6.1 Pa / (cm / s) / cm. The combined particle capture efficiency of these multiple filter media sections is greater than 97%, and their total thickness is sufficient to fill the usable volume of the vent housing.

[0078] The carbon media #2 vent assembly comprises multiple filter media sections, including efficiency sections and spacer sections. Each efficiency section consists of four discrete and identical reference filter media layers. Spacer sections are positioned between each pair of successive efficiency sections in the series. Each spacer section is a single layer of adsorbent carbon filter material. Each spacer section has a nominal Fraser permeability of 1699 L / m³. 2 sec (209 ft 3 / min / ft 2The filter media has a flow resistance of 8.4 Pa / (cm / s) / cm. The total particle capture efficiency of these multiple filter media sections is greater than 97%, and the total thickness is sufficient to fill the usable volume of the vent housing.

[0079] like Figure 11 As can be seen, the carbon medium #1 vent assembly and the carbon medium #2 vent assembly take at least two hours longer to reach the terminal pressure drop than the reference vent assembly. These performance differences are related to the fact that, in embodiments where the vent assembly is exposed to oil vapor, the carbon medium vent assembly has a relatively longer effective service life than the reference vent assembly.

[0080] Figure 12 The test results reflect the following situations, and these results will be referenced in the above text. Figures 10 to 11 The exemplary vent assembly described is compared by challenging each vent assembly with a constant flow rate of oil aerosol over time and recording the pressure difference across the vent assembly over time until the terminal pressure difference is reached. Figure 13 The illustrative test setup depicted represents the test described hereafter. Each carbon-medium vent assembly achieved terminal pressure within 20% of the time it took the baseline vent assembly to reach terminal pressure, which is related to a similar effective service life for vent assemblies exposed to oil aerosols.

[0081] It should be noted that while the various test results disclosed herein utilize the same efficiency segments and the same spacer segments, this is only to help isolate variables that may affect the performance of the vent assembly. Depending on the specific implementation, it may be desirable to combine one or more efficiency segments with material properties that differ from one or more other efficiency segments, such as permeability, particle capture efficiency, flow resistance, and thickness (as an example). Similarly, one or more spacer segments may have material properties that differ from one or more other spacer segments. Furthermore, it may be desirable to combine intermediate segments within these multiple filter media segments—intermediate segments that are neither efficiency segments nor spacer segments.

[0082] Figure 14 This is a flowchart depicting a method consistent with the techniques disclosed herein. Method 400 is generally consistent with the manufacture of vent assemblies.

[0083] A vent housing 410 is obtained. Filter media sections are arranged in series within the housing 420. A media spacer is inserted into the housing 430. A membrane is attached to the housing 440. A cover is attached to the housing 450.

[0084] Obtaining the vent housing 410 may include forming the vent housing. The vent housing is generally formed to have a first end and a second end and to define an airflow path extending from the first end to the second end. The vent housing 410 may be formed consistently using methods generally understood in the art. In one embodiment, the vent housing 410 is formed by an injection molding process. In another embodiment, the vent housing 410 is formed by a blow molding process. The vent housing 410 may be formed from a wide variety of materials and combinations of materials discussed above.

[0085] When filter media sections are arranged in the housing 420, they are typically arranged within the airflow path. Efficiency sections and spacer sections are positioned in the housing alternately along the airflow path. The material composition and properties of the efficiency sections and spacer sections have been described in detail above. In some embodiments, arranging the multiple filter media sections in the airflow path of the housing can be performed such that some of the filter media sections are misaligned with some of the other filter media sections. This misalignment of at least a portion of the multiple filter media sections can have the advantage of preventing air within the vent assembly from bypassing the filter media.

[0086] Inserting a media spacer into the housing 430 helps to accommodate the plurality of filter media segments within the housing. In one embodiment, the media spacer and the vent housing define an interference fit such that inserting the media spacer into the housing 430 causes the connection structure defined by the media spacer to engage with the mating structure defined by the vent housing. In an alternative embodiment, the media spacer may be bonded to the vent housing, for example, by thermal welding or adhesive.

[0087] The membrane is generally coupled to the vent housing 440 in a relationship spaced apart from the plurality of filter media sections. In various embodiments, the membrane is coupled to a membrane receiving surface 440 defined by the vent housing. In one embodiment, the membrane is coupled to the vent housing 440 by an adhesive. In another embodiment, the membrane is coupled to the vent housing 440 by welding (e.g., thermal welding or ultrasonic welding). It should be noted that in some embodiments, no membrane is used in the vent assembly. In such embodiments, the housing 440 is not coupled with a membrane.

[0088] In various embodiments, the method of manufacturing the vent assembly may include the additional step of attaching a cover to the housing 450 to shield the flow surface of the membrane or the flow surface of the plurality of filter media layers (where the membrane is omitted) from environmental influences. Exemplary aspects

[0089] Aspect 1. A vent assembly comprising: A vent housing having a first end and a second end, wherein the vent housing defines a mounting structure and an airflow path extending from the mounting structure to the outside of the vent housing; and Multiple filter media sections are arranged in series along the airflow path, wherein the multiple sections are configured to span the airflow path, wherein the multiple filter media sections include efficiency sections and spacer sections, the efficiency sections and the spacer sections alternate in the series, and wherein each spacer section has a flow resistance of up to 80% of the flow resistance of each efficiency section.

[0090] Aspect 2. The vent assembly as described in any one of Aspects 1 and 3 to 14, wherein the plurality of sections comprises at least five sections.

[0091] Aspect 3. The vent assembly as described in any one of Aspects 1 to 2 and 4 to 14, wherein the vent assembly comprises at least 7 segments per 100 mm of tandem thickness.

[0092] Aspect 4. The vent assembly as described in any one of Aspects 1 to 3 and 5 to 14, wherein each efficiency section has a flow resistance of 25.5 Pa / (cm / s) / cm to 125 Pa / (cm / s) / cm.

[0093] Aspect 5. The vent assembly as described in any one of Aspects 1 to 4 and 6 to 14, wherein each spacer segment has a flow resistance of up to 23.6 Pa / (cm / s) / cm.

[0094] Aspect 6. The vent assembly as described in any one of Aspects 1 to 5 and 7 to 14, wherein, at 10.34 kPa, the combined thickness of the efficiency section is 70% to 95% of the total thickness of the series.

[0095] Aspect 7. The vent assembly as described in any one of Aspects 1 to 6 and 8 to 14, wherein the tandem assembly has a total particle capture efficiency of at least 97%.

[0096] Aspect 8. The vent assembly as described in any one of Aspects 1 to 7 and 9 to 14, wherein each efficiency segment has a particle capture efficiency greater than 75%.

[0097] Aspect 9. The vent assembly as described in any one of Aspects 1 to 8 and 10 to 14, wherein, at 10.34 kPa, each segment has a density of 0.10 g / cm³. 3 Up to 0.4 g / cm 3 .

[0098] Aspect 10. The vent assembly as described in any one of Aspects 1 to 9 and 11 to 14, wherein the plurality of segments comprise adhesive fibers and glass fibers.

[0099] Aspect 11. The vent assembly as described in any one of Aspects 1 to 10 and 12 to 14, further comprising a membrane disposed in the vent housing across an airflow path between the plurality of sections and the external environment.

[0100] Aspect 12. The vent assembly as described in any one of Aspects 1 to 11 and 13 to 14, further comprising an adsorbent layer configured to span an airflow path between the membrane and the plurality of segments.

[0101] Aspect 13. The vent assembly as described in any one of Aspects 1 to 12 and 14, wherein at least one spacer layer comprises an adsorbent.

[0102] Aspect 14. The vent assembly as described in any one of Aspects 1 to 13, wherein each spacer segment has a Fraser permeability of at least 200 ft. 3 / min / ft 2 .

[0103] Aspect 15. A vent assembly comprising: A vent housing having a first end and a second end, wherein the vent housing defines a mounting structure and an airflow path extending from the mounting structure to the outside of the vent housing; and Multiple filter media sections are arranged in series along the airflow path, wherein the multiple sections are configured to span the airflow path, wherein the multiple filter media sections include efficiency sections and spacer sections, the efficiency sections and the spacer sections alternating in the series, wherein the series has a total particle capture efficiency of at least 97%, and wherein each efficiency section has a particle capture efficiency of at least 80%.

[0104] Aspect 16. The vent assembly as described in any one of Aspects 15 and 17 to 28, wherein the plurality of sections comprises at least five sections.

[0105] Aspect 17. The vent assembly as described in any one of Aspects 15 to 16 and 18 to 28, wherein the vent assembly comprises at least 7 segments per 100 mm of tandem thickness.

[0106] Aspect 18. The vent assembly as described in any one of Aspects 15 to 17 and 19 to 28, wherein each efficiency section has a flow resistance of from 25.5 Pa / (cm / s) / cm to 125 Pa / (cm / s) / cm.

[0107] Aspect 19. The vent assembly as described in any one of Aspects 15 to 18 and 20 to 28, wherein each spacer segment has a flow resistance of up to 23.6 Pa / (cm / s) / cm.

[0108] Aspect 20. The vent assembly as described in any one of Aspects 15 to 19 and 21 to 28, wherein, at 10.34 kPa, the combined thickness of these efficiency sections is 70% to 95% of the total thickness of the series.

[0109] Aspect 21. The vent assembly as described in any one of Aspects 15 to 20 and 22 to 28, wherein each spacer segment has a flow resistance of up to 80% of the flow resistance of each efficiency segment.

[0110] Aspect 22. The vent assembly as described in any one of Aspects 15 to 21 and 23 to 28, wherein each efficiency segment has a particle capture efficiency of at least 85%.

[0111] Aspect 23. The vent assembly as described in any one of Aspects 15 to 22 and 24 to 28, wherein, at 10.34 kPa, each segment has a density of 0.10 g / cm³. 3 Up to 0.4 g / cm 3 .

[0112] Aspect 24. The vent assembly as described in any one of Aspects 15 to 23 and 25 to 28, wherein the plurality of segments comprise adhesive fibers and glass fibers.

[0113] Aspect 25. The vent assembly as described in any one of Aspects 15 to 24 and 26 to 28, further comprising a membrane disposed in the vent housing across an airflow path between the plurality of sections and the external environment.

[0114] Aspect 26. The vent assembly as described in any one of Aspects 15 to 25 and 27 to 28, further comprising an adsorbent layer configured to span an airflow path between the membrane and the plurality of segments.

[0115] Aspect 27. The vent assembly as described in any one of Aspects 15 to 26 and 28, wherein at least one spacer layer comprises an adsorbent.

[0116] Aspect 28. The vent assembly as described in any one of Aspects 15 to 27, wherein each spacer segment has a Fraser permeability of at least 200 ft. 3 / min / ft 2 .

[0117] It should also be noted that, as used in this specification and the appended claims, the phrase "configured as" describes a system, device, or other structure that is constructed to perform a particular task or employ a particular configuration. The term "configured as" may be used interchangeably with similar terms such as "arranged as," "constructed as," "manufactured as," etc.

[0118] As used herein, the term "about" allows for a degree of variation in the value or range, for example, within 10%, 5%, or 1% of the specified limit of the value or range, and includes the exact specified value or range. As used herein, the term "substantially" means most or the majority, such as at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.

[0119] All publications and patent applications in this specification are intended to be at the level of a person skilled in the art to which this invention pertains. All publications and patent applications are incorporated herein by reference to the extent that each individual publication or patent application is explicitly and individually identified by reference. In the event of any inconsistency between the disclosure of this application and the disclosure of any document incorporated herein by reference, the disclosure of this application shall prevail.

[0120] This application is intended to cover modifications or variations to the subject matter of this invention. It should be understood that the above description is intended to be illustrative rather than restrictive, and the claims are not limited to the illustrative embodiments set forth herein.

Claims

1. A vent assembly, the vent assembly comprising: A vent housing having a first end and a second end, wherein the vent housing defines a mounting structure and an airflow path extending from the mounting structure to the outside of the vent housing; and Multiple filter media sections are arranged in series along the airflow path, wherein the multiple sections are configured to span the airflow path, wherein the multiple filter media sections include efficiency sections and spacer sections, the efficiency sections and the spacer sections alternate in the series, and wherein each spacer section has a flow resistance of up to 80% of the flow resistance of each efficiency section.

2. The vent assembly as claimed in any one of claims 1 and 3 to 10, wherein, These multiple sections include at least five sections.

3. The vent assembly as claimed in any one of claims 1 to 2 and 4 to 10, wherein, The vent assembly comprises at least 7 sections per 100 mm of tandem thickness.

4. The vent assembly as claimed in any one of claims 1 to 3 and 5 to 10, wherein, The flow resistance of each efficiency section ranges from 25.5 Pa / (cm / s) / cm to 125 Pa / (cm / s) / cm.

5. The vent assembly as claimed in any one of claims 1 to 4 and 6 to 10, wherein, The flow resistance of each spacer section is up to 23.6 Pa / (cm / s) / cm.

6. The vent assembly as claimed in any one of claims 1 to 5 and 7 to 10, wherein, At 10.34 kPa, the combined thickness of these efficiency sections is 70% to 95% of the total thickness of the tandem.

7. The vent assembly as claimed in any one of claims 1 to 6 and 8 to 10, wherein, Each efficiency band has a particle capture efficiency of more than 75%.

8. The vent assembly as claimed in any one of claims 1 to 7 and 9 to 10, wherein, At 10.34 kPa, the density of each segment ranges from 0.10 g / cm³. 3 Up to 0.4 g / cm 3 .

9. The vent assembly as claimed in any one of claims 1 to 8 and 10, further comprising a membrane disposed in the vent housing across an airflow path between the plurality of sections and the external environment.

10. The vent assembly as claimed in any one of claims 1 to 9, wherein, At least one spacer layer includes an adsorbent.

11. A vent assembly, comprising: A vent housing having a first end and a second end, wherein the vent housing defines a mounting structure and an airflow path extending from the mounting structure to the outside of the vent housing; and Multiple filter media sections are arranged in series along the airflow path, wherein the multiple sections are configured to span the airflow path, wherein the multiple filter media sections include efficiency sections and spacer sections, the efficiency sections and the spacer sections alternating in the series, wherein the series has a total particle capture efficiency of at least 97%, and wherein each efficiency section has a particle capture efficiency of at least 80%.

12. The vent assembly as claimed in any one of claims 11 and 13 to 20, wherein, These multiple sections include at least five sections.

13. The vent assembly as claimed in any one of claims 11 to 12 and 14 to 20, wherein, The vent assembly comprises at least 7 sections per 100 mm of tandem thickness.

14. The vent assembly as claimed in any one of claims 11 to 13 and 15 to 20, wherein, The flow resistance of each efficiency section ranges from 25.5 Pa / (cm / s) / cm to 125 Pa / (cm / s) / cm.

15. The vent assembly as claimed in any one of claims 11 to 14 and 16 to 20, wherein, The flow resistance of each spacer section is up to 23.6 Pa / (cm / s) / cm.

16. The vent assembly as claimed in any one of claims 11 to 15 and 17 to 20, wherein, At 10.34 kPa, the combined thickness of these efficiency sections is 70% to 95% of the total thickness of the tandem.

17. The vent assembly as claimed in any one of claims 11 to 16 and 18 to 20, wherein, The flow resistance of each spacer section is up to 80% of the flow resistance of each efficiency section.

18. The vent assembly as claimed in any one of claims 11 to 17 and 19 to 20, wherein, At 10.34 kPa, the density of each segment ranges from 0.10 g / cm³. 3 Up to 0.4 g / cm 3 .

19. The vent assembly as claimed in any one of claims 11 to 18 and 20, wherein, These multiple sections include adhesive fibers and glass fibers.

20. The vent assembly as claimed in any one of claims 11 to 19, wherein, Each spacer section has a Fraser permeability of at least 200 ft. 3 / min / ft 2 .

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