Filter assembly for filtering surgical smoke, and filter insert for a FLUE gas filter

Abstract

A filter assembly for a smoke evacuation unit, and / or a filter insert for a flue gas filter. A housing includes an inlet, an outlet, and a partition wall defining a liquid collection compartment. A separation element, such as prefilter media, may be disposed between the inlet and a filter, for example, an ULPA filter stage. The prefilter media may be treated or formed with a coalescing material. A prefilter assembly may include a frame secured to the housing and defining a window, and the prefilter media sealed to the frame to cover the window. A lower panel of the frame may be sloped to provide a liquid guide. The frame may serve as a spacer to maintain separation between the prefilter media and the filter by a void space of sufficient distance. A treatment device, the flue gas filter, and the use of the flue gas filter are also disclosed.

Description

FILTER ASSEMBLY FOR FILTERING SURGICAL SMOKE, AND FILTER INSERT FOR A FLUE GAS FILTERCROSS REFRENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and all the benefits of German Patent Application No. 10 2024 128 753.5, filed October 4, 2024, and United States Provisional Patent Application No. 63 / 693,542, filed September 11, 2024, the entire contents of each being hereby incorporated by reference.BACKGROUND

[0002] Surgical smoke, also referred to herein as flue gases, includes aerosolized combustion byproducts produced by heat-generating surgical instruments, such as lasers, electrosurgery, ultrasonic devices, drills, and saws. This surgical instrument is used for, among other things, ablation (tissue removal) and cauterization (tissue burning) using electric current. The use of electromagnetic waves from lasers, such as the excimer laser, or vibrating high- frequency blades, so-called ultrasonic dissectors, are increasingly replacing the traditional scalpel in many medical procedures (e.g., laparoscopic procedures). Advantages of this new generation of surgical instruments include, among others, the coagulation of opened blood vessels during tissue separation, which is caused by heat-induced denaturation of proteins.

[0003] The aerosolized chemicals and substances may include carcinogenic matter, blood and tissue particles, bacteria, viruses, and other material hazardous to health. Depending on the type and duration of an intervention, the medical personnel involved may be exposed to the flue gases for several hours, leading to acute intoxication with symptoms such as headaches, nausea, and / or irritation of the mucous membranes. Literature suggests that perioperative teams exposed to surgical smoke report twice as many respiratory health issues as the general public. In certain instances, the smoke can be thick enough to obscure vision, especially during longer operations where cauterizing tools are heavily used, along with noxious odors. Thus, the smoke gases not only impair occupational safety, but also pose a risk to the patient. Therefore, ongoing efforts have been directed to reducing and eliminating the presence of surgical smoke in the operating room.

[0004] Furthermore, liquid is often entrained within the surgical smoke being suctioned from within or near’ the surgical site. The filter media of the filter assembly may not be especially well suited for excessive amounts of liquid. Known extraction devices commonly usedfor this purpose have a flue gas filter with a liquid separator separate from a filter insert that filters both particulate and gaseous substances. In practice, the filter insert is, for example, a combination of an ultra-low particular air (ULPA) filter, and an activated carbon filter. The filter insert is arranged separately from the liquid separator to prevent contamination of the subsequent filter stages by the liquid and to ensure the function of the flue gas filter during operation. However, the separate arrangement leads to a large space requirement for the flue gas filter and thus the treatment device, as well as complicated handling, which makes compliance with hygiene standards more difficult. Likewise, a fluid trap positioned upstream from the filter assembly may be configured to collect the liquid within the surgical smoke before entering the filter assembly. Among other disadvantages, the fluid trap is a separate component requiring additional setup and resulting in additional environmental waste.

[0005] Therefore, there is a need in the art for a filter assembly that provides for improved means for separating liquid from the surgical smoke being drawn through the filter assembly, and done so in a manner that requires no additional burden on the user. Additional shortcomings in the art overcome by further inventive aspects will be readily appreciated from the disclosure.SUMMARY

[0006] The inventive aspects disclosed and claimed herein are directed to a filter assembly and a filter insert that avoids the above-described disadvantages. Furthermore, the inventive aspects aim to provide a flue gas filter and a treatment device, each with the filter insert, which require less space and are easier to handle. The inventive aspects also aim to create a use for the filter insert. As used herein, the filter assembly may be for a smoke evacuation unit, and the filter insert may be for a flue gas filter; however, the terminology and the features may be interchangeable and combinable in any suitable manner to the extent not incompatible. The filter assembly and the filter insert are configured to filter smoke - e.g., surgical smoke, flue gases, etc. - in a manner that minimizes contamination of a primary filter (e.g., the ULPA filter) from liquid entrained in the smoke.

[0007] This objective is achieved by a filter assembly and a filter insert according to the independent claims and clauses provided herein. Advantageous developments are the subject of dependent claims and clauses provided herein. Even further inventive aspects of the disclosureare directed to a treatment device with a tool intended to act thermally on a human or animal body, in particular for separating organic material, and with a smoke gas extraction device, wherein the smoke gas extraction device has a suction nozzle arranged adjacent to the tool, in such a way that smoke gases released during the thermal action are sucked into the smoke gas extraction device through the suction nozzle, wherein the smoke gas extraction device has a flue gas filter for cleaning the smoke gases, wherein the flue gas filter contains a filter insert according to one of the embodiments disclosed herein. Still further aspects of the disclosure are directed to use of a flue gas filter in a therapeutic, in particular surgical, field, wherein the flue gas filter contains a filter insert according to one of the embodiments disclosed herein.

[0008] Certain disclosed embodiments are directed to the filter assembly for filtering surgical smoke. The filter assembly includes a housing defining an enclosure. The housing include a filter casing, and a cover coupled to the filter casing to define several internal compartments of the enclosure. A rear’ side of the housing may define an outlet. The cover of the housing defines an inlet, for example, one or more inlet ports configured to be removably coupled with a suction tube. The inlet is in fluid communication with the outlet so as to provide a suction path through the enclosure of the filter assembly.

[0009] The housing may define a smoke ingress compartment, a filter media compartment, and a liquid collection compartment. The inlet opens into the smoke ingress compartment. The smoke ingress compartment is positioned forward or distal to the filter media compartment, and above the liquid collection compartment. The liquid collection compartment is disposed below or beneath the filter media compartment. A partition wall or a barrier separates the liquid collection compartment from the filter media compartment. The partition may extend from the rear side of the housing. A sorbent, such as one or more pieces of foam media or superabsorbing fiber or polymer, may be disposed within the liquid collection compartment.

[0010] A filter is disposed within the filter media compartment. Suction from the vacuum source of the smoke evacuation unit provides a suction path from the suction tube and through the inlet and the filter of the filter media compartment to be discharged through the outlet. The filter may be formed from a plurality of filter stages or layers, also referred to as a filter stack. A first filter stage may be a prefilter assembly, a second filter stage may be an ULPA filter, and a third filter stage may be a charcoal filter.

[0011] The prefilter assembly may be disposed within the filter media compartment. The filter is disposed between the prefilter assembly and the outlet. A sensor assembly may be disposed between the inlet and the prefilter assembly such that the sensor detects particulates within the surgical smoke before encountering the prefilter assembly. The prefilter assembly includes prefilter media, also referred to herein as a separation element.

[0012] The prefilter media is treated or formed with a coalescing material, in particular a coating that is repellant to liquids, such as a hydrophobic or oleophobic coating, a coating of per- and polyfluoroalkyl substances (PFAS), or the like. The prefilter media may be a mesh-like perforated structure or a mesh or lattice-like braid / fabric. Upon contact with the prefilter media, the liquid is promoted to agglomerate or coalesce on or within the prefilter media rather than pass therethrough. The denser liquid molecules descend along an outer surface of the prefilter media into the liquid collection device under the influence of gravity. More specifically, the liquid molecules descend along an outer surface of the prefilter media and onto the liquid guide and into the liquid collection compartment. The gas of the surgical smoke passes through the prefilter media and into the filter of the filter assembly. The prefilter assembly is spaced apart from the filter stack. A rear of the frame is separated from the second filter stage of the filter stack by a void space such that the frame acts a spacer.

[0013] Certain embodiments are directed to the filter insert for a flue gas filter, as well as the flue gas filter, a treatment device comprising the flue gas filter, and a use of the flue gas filter. The filter insert comprises a housing with an inlet and an outlet, which are fluidically connected, and at least two filter stages arranged between the inlet and the outlet.

[0014] The filter insert has a first filter stage and a second filter stage. The first filter stage is designed as a liquid separator and has a separation element. Furthermore, the filter insert has a liquid collection device, which, in use, is arranged lower than the liquid separator and is spatially separated from the second filter stage. Additionally, the filter insert has a liquid guide, which is designed to guide liquid from the separation element into the liquid collection device. The filter insert also has a spacer that keeps the first filter stage at a distance from the second filter stage downstream in the flow direction.

[0015] The integration of the liquid separator into the filter insert in combination with a different filter stage has the advantage of a space-optimized filter insert with only limited available space within a flue gas filter. By introducing a filter insert instead of various separatecomponents that serve to filter smoke gases, the risk of contamination of the individual components as well as the flue gas filter as a whole is reduced, since only the insertion of a filter insert is necessary instead of assembling and connecting several components for a corresponding flue gas filter. The inventive arrangement of the liquid collection device and the spacing of the filter stages from each other reliably ensures that no contamination of the second filter stage, especially by liquid, occurs.

[0016] The flow direction of the fluid is from the inlet to the outlet. The first filter stage following the inlet is designed as a liquid separator in such a way that liquid separated from the fluid flowing through the separation element is transported by the liquid guide, in the manner of a drainage, to the liquid collection device. The separation element can, for example, be welded, glued, clamped, or otherwise connected directly to the housing of the filter insert. Advantageously, the separation element is connected to a frame that completely or partially surrounds the separation element and is in turn connected to the housing. The connection of the separation element to the frame and / or the housing is designed to be circumferentially tight so that the fluid necessarily passes through the separation element in the first filter stage. For this purpose, a molded or fitted seal can surround the frame and / or the housing. Additionally or alternatively, an integrated labyrinth seal can be present in the frame and / or housing to prevent contamination of the subsequent filter stage. It can be provided that the pail of the frame facing the liquid collection device has a raised portion compared to the rest of the frame. This frame elevation can prevent liquid from being pressed through the separation element. This is advantageous, among other things, in the event of a backup of drained liquid.

[0017] Furthermore, in use, the liquid collection device is at least arranged lower than the liquid separator, so that it is at least partially located below the separation element, allowing the separated liquid to drip or flow into the lower-lying liquid collection device by gravity. A flow that may arise from the separation of the liquid can also accelerate the separation or drainage of the liquid with such an arrangement of the liquid collection device.

[0018] The liquid collection device can advantageously include a storage medium that serves to absorb the separated liquid and retain it within the liquid collection device. This can be, in particular, a sponge, granulate, beads, nonwoven fabric, or foam. Materials such as zeolite, silica, or a superabsorbent can be used for this purpose. The storage medium can also be firmly connected to the liquid collection device to prevent the medium and the contained liquid fromescaping. For this, the storage medium can, for example, be glued, welded, or clamped into the liquid collection device. In certain embodiments, the storage medium is designed as a mat that extends within the liquid collection device at least below the first filter stage. The absorption capacity of the storage medium and the liquid collection device can differ from each other. Thus, the liquid collection device can have a higher absorption capacity than the storage medium. This ensures that when the maximum absorption capacity of the storage medium is reached, no liquid escapes from the liquid collection device and, for example, contaminates the second filter stage. The absorption capacity of the storage medium and / or the liquid collection device is, in particular, 500 ml, preferably 250 ml, especially preferably 175 ml. In certain embodiments, the absorption capacity of the storage medium and / or the liquid collection device is 25 ml, preferably 12 ml, especially preferably less than 10 ml. An absorption capacity of a maximum of 25 ml is particularly advantageous for minimizing the required installation space. This is advantageous for operations and / or treatments with relatively low liquid separation, such as minimally invasive or endoscopic procedures, which are mostly performed in smaller operating rooms or treatment rooms.

[0019] Furthermore, the liquid collection device is separated from the second filter stage in such a way that the liquid absorbed by the liquid collection device cannot contaminate the second filter stage. For this purpose, the greatest possible spatial distance within the filter insert can be used. In certain embodiments, the liquid collection device can extend below the filter stages over the entire, especially horizontally measured, length of the insert housing. In an alternative embodiment, the liquid collection device can be spatially upstream of the second filter stage, contrary to the flow direction.

[0020] The liquid guide can completely or partially include the separation element. In certain embodiments, the liquid guide extends into the liquid collection device. Advantageously, the mouth of the liquid guide overlaps with the liquid collection device, thus forming a spill protection.

[0021] The sieve is formed by a mesh-like perforated structure or a mesh or lattice-like braid / fabric. Due to the hydrophobic material properties, liquid cannot pass through the separation element and is guided via the liquid guide into the liquid collection device or drips into it. In certain embodiments, a gradual course of hydrophobicity of the sieve can be provided. The separation element is essentially flat or curved, in particular curved against the flow direction.

[0022] In certain embodiments, the separation element is inclined against the flow direction. This means, in particular, that a surface of the separation element facing the inlet is angled at an inclination angle of less than 90° to the flow direction. The positioning against the flow direction is to be understood such that the separation element, in contrast to its arrangement perpendicular to the flow direction, is pivoted about an axis perpendicular' to the flow direction, which is arranged in the area of the end of the separation element facing the liquid collection device. Particularly advantageously, the inclination angle is 80° to 87°. This has the advantage that liquid droplets can drip directly from the separation element into the liquid collection device along gravity, without requiring disproportionate installation space. This promotes rapid dripping of the liquid, which prevents liquid-induced film formation on the separation element and has a positive influence on the differential pressure. Furthermore, the risk of liquid droplets being pressed through the separation element with the danger of contamination of the subsequent filter stage is reduced or eliminated.

[0023] The spacer for spacing the first filter stage from the second filter stage downstream in the flow direction can be introduced as a separate component into the insert housing or provided in the insert housing. Advantageously, the spacer is part of the first or second filter stage. In certain embodiments, the first filter stage has the spacer. In particular, the spacer is formed by the frame. Furthermore, a spacer can be provided between the second and third filter stages. This can in turn be located on the second and / or third filter stage or be constructed as a separate component. In certain embodiments, the spacer can be formed by an intermediate wall located in the insert housing, in particular the intermediate wall serving to fix the filter stages.

[0024] In certain embodiments, the first filter stage is arranged at a distance of 2 mm to 25 mm from the second filter stage. A distance of 5 mm or in particular 8 mm between both filter stages is preferred, especially with regal'd to the smaller installation space. A distance of 25 mm between both filter stages is particularly advantageous to avoid contamination of the subsequent filter stage with liquid.

[0025] In certain embodiments, a partition wall abuts both sides of the insert housing. In another embodiment, the insert housing has a liquid-impermeable partition wall, which is arranged between the liquid collection device and the second filter stage. The partition wall runs, at least in pail, between the liquid collection device and the second filter stage and is optionally enclosed by the insert housing. The partition wall can extend from an outer wall of the inserthousing into an interior of the insert housing. Tn certain embodiments, the partition wall extends from the side of the insert housing forming the outlet against the flow direction, in particular up to next to the first filter stage, whereby the partition wall is liquid-tight on two opposing longitudinal sides, which extend in the flow direction and at least partially vertically, of the insert housing, in such a way that at least the filter stages downstream of the first filter stage are located above the partition wall and the liquid collection device is located below the partition wall.

[0026] In certain embodiments, the liquid collection device has a cover at the end facing the second filter stage. This advantageously provides splash protection to prevent contamination of the subsequent filter stage. In one design, the partition wall can merge into the cover. In certain embodiments, the cover can be designed as a grid. This is advantageous when using a storage medium, such as a granular or gel-like storage medium, so that if the diameter of the storage medium is larger than the diameter of the grid meshes, the storage medium is retained in the liquid collection device.

[0027] In certain embodiments, the liquid guide can be formed by a frame surrounding the separation element. In another embodiment, the frame forms the liquid guide entirely or partially. In an alternative embodiment, the liquid guide is formed by the insert housing. In a fourth embodiment, the liquid guide is attached as a separate component between or on the frame and / or insert housing. In a fifth embodiment, the liquid guide is formed by the partition wall.

[0028] In certain embodiments, a further filter stage designed as a liquid separator, which is upstream of the second filter stage in the flow direction and has another separation element and a liquid guide designed to guide liquid from the further separation element into a liquid collection device, can be included. Advantageously, it can be provided that a further filter stage designed as a liquid separator is upstream of the second filter stage. This includes at least one further separation element. The first and the further separation element can share a frame and / or a liquid guide and / or a liquid collection device. The separation elements can be elements of the same or different types. In certain embodiments, it can be provided that the separation element of the first filter stage is designed as a coalescer for coagulating liquid droplets and the further separation element of the further filter stage is designed as a hydrophobic sieve.

[0029] In the disclosed embodiments, the frame may be secured to the housing with a flange extending around a perimeter of the frame, and the flange is secured to the lip of the housing, e.g., the filter casing. The frame may include one or more ribs disposed on an exterior surface ofone or more sides of the frame. The ribs may be positioned rearwardly to the flange on a bottom panel of the frame. The bottom panel of the frame is sloped, and the ribs provide a flat-on-flat interface between the top panel of the frame and filter casing, and the lower side of the frame and the partition wall.

[0030] The frame may include an interior rim associated with each of the top, bottom, and side panels. The interior rim may define a portion of the windows. A bonding face may be recessed slightly from the interior rim such that the interior rim is a standoff. The bonding face being recessed accommodates a thin layer of adhesive to be applied, thereby providing a flat perimeter seal about an entirety of the filter media. The frame may include one or more ridges defining channels therebetween providing the liquid guide. The ridges are disposed on at least the bottom panel of the frame, and, optionally, on the top panel of the frame. Upper surfaces of the ridges may be oriented substantially perpendicular to the bonding face. As shown, the ridges may taper in a rearward direction towards the bonding face in a manner complementary to an extent of slope of the bottom panel, frame may include one or more struts extending between the sides. The struts and the sides of the frame define the windows. The prefilter media is secured to the frame to cover the windows.

[0031] According to certain inventive aspects, a flue gas filter is also provided, with a filter inlet and a filter outlet and a filter chamber in the flow direction between the filter inlet and the filter outlet, wherein a filter insert as disclosed and claimed herein is arranged in the filter chamber in such a way that, in use, the smoke gas flowing into the flue gas filter flows through the filter insert. The filter insert has a tightness such that the smoke gas flowing into the flue gas filter in use flows through the filter insert. In certain embodiments, the filter insert is detachably connected to the flue gas filter. This enables regular replacement of the filter insert to create the most hygienic working environment possible.

[0032] Further features, details, and advantages of the inventive aspects result from the wording of the claims as well as from the following description of exemplary embodiments with reference to the drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a perspective view of an embodiment of a filter assembly, also referred to herein as a first embodiment of the filter insert.

[0034] FIG. 2 is a perspective exploded view of the filter assembly in which a cover is decoupled from a housing to visualize a prefilter assembly disposed therein.

[0035] FIG. 3 is a sectional elevation view of the filter assembly of FIG. 1 taken along lines 3-3.

[0036] FIG. 4 is an exploded view of the prefilter assembly.

[0037] FIG. 5 is a view of a longitudinal section through a second embodiment of a filter insert.

[0038] FIG. 6 is a longitudinal section through a third embodiment of a filter insert.

[0039] FIG. 7 is a longitudinal section through a fourth embodiment of a filter insert.

[0040] FIG. 8 is a longitudinal section through a separation element and a liquid collection device.

[0041] FIG. 9 is a longitudinal section through a first filter stage.

[0042] FIG. 10 is a section of a front view of a separation element with frame.

[0043] FIG. 11 is a sectional view of a frame with the separation element.

[0044] FIG. 12 is a longitudinal section through a fifth embodiment of a filter insert.

[0045] FIG. 13 is a longitudinal section through a sixth embodiment of a filter insert.DETAILED DESCRIPTION

[0046] FIGS. 1-3 depict an exemplary embodiment of the filter assembly 10. The illustrated embodiment may be for use with a surgical a smoke evacuation unit (not shown). The smoke evacuation unit may include a vacuum source, and receive the filter assembly 10 or filter insert 10 inline between the suction instrument and the vacuum source. The smoke evacuation unit includes a filter receptacle within which the filter assembly 10 is configured to be removably inserted. The smoke evacuation unit may also a controller is configured to control the vacuum source. The smoke evacuation unit may be implemented as a console situated on a tabletop within the operating room, for example, the SafeAir Compact Evacuator sold by Stryker Corporation (Kalamazoo, Mich.). The smoke evacuation unit and the filter assembly may also be usable with an electrosurgical unit with a treatment tool. Other embodiments include the smoke evacuation unit being structurally and functionally integrated with a medical waste management system, for example, the Neptune system manufactured by Stryker Corporation and disclosed in commonly-owned United States Patent Publication No. 2007 / 0135779, published June 14, 2007, the entire contents of which arc hereby incorporated by reference.

[0047] The filter assembly 10 includes a housing 12 defining an enclosure 17. The housing 12 has a shape complementary to a shape of the receptacle into which the filter assembly 10 is configured to be removably inserted. The housing 12 may be formed from a filter casing 16, and a cover 14 coupled to the filter casing 16 to define several internal compartments of the enclosure 17 to be described. As best shown in FIG. 3, the filter casing 16 may be generally boxshaped and define a front opening 18 through which internal components of the filter assembly 10 may be assembled. The cover 14 is sized and shaped to cover the front opening 18. The cover 14 may be secured to the filter casing 16, for example, with fasteners, clips, laser or ultrasonic welding, or other suitable joining means. Alternatively, the cover 14 may be removably coupled to the housing 12. The cover 14 may be sized slightly larger than the housing 12 so as to form a lip or flange configured to abut a front edge of the filter receptacle with the filter assembly 10 inserted therein.

[0048] A rear side 20 of the housing 12 may define an outlet 22 configured to be arranged in fluid communication with the vacuum source of the smoke evacuation unit. In certain embodiments, an electronic connector (not shown) may be coupled to and disposed on the rear side 20. The electronic connector is configured to provide electronic communication with an electronic connector of the smoke evacuation unit through which power, data, and / or other signals may be transmitted therebetween.

[0049] The cover 14 of the housing 12 defines an inlet 24, for example, one or more inlet ports configured to be removably coupled with a suction tube. The illustrated embodiment includes three suction ports. A port cover assembly may be coupled to the cover 14 and include port covers 26 movably disposed over a respective one of the inlet ports. For example, the port covers 26 may be formed from a flexible, resilient material such as a rubber, or a semi-rigid or rigid material that is flexibly coupled to the housing 12. The port covers 26 preserve a sealed pathway through the filter assembly 10 by preventing ingress of ambient air through the inlet port(s) not in use. The cover 14 may also be formed or shaped to define a cavity sized to provide the handle 28 for manipulating the filter assembly 10, such as installing into or removing from the filter receptacle, or otherwise carrying it about the medical facility.

[0050] As best shown in FIG. 3, the filter casing 16 of the filter assembly 10 defines a smoke ingress compartment 30, a filter media compartment 32, and a liquid collection compartment 34. The inlet 24 opens into the smoke ingress compartment 30. The smoke ingress compartment 30 may be considered a manifold through which the incoming surgical smoke is routed to the filter media compartment 32. The smoke ingress compartment 30 is positioned forward or distal to the filter media compartment 32, and above the liquid collection compartment 34, also referred to herein as a liquid collection device. In certain embodiments, the filter assembly 10 includes a sensor assembly 36 disposed within the smoke ingress compailment 30. The sensor assembly 36 may include a sensor housing 38 coupled to the filter casing 16 and positioned near an upper side of the housing 12, and a sensor 40 coupled to the sensor housing 38. The sensor 40 is in electronic communication with a printed circuit board (PCB) unit (not shown), for example, through a wire or a wire harness extending through the smoke ingress compartment 30 and a sealed grommet 42. The sensor 40 is configured to detect a characteristic of the gas passing through the smoke ingress compailment 30. In particular, the sensor 40 is configured to detect particulates associated with the surgical smoke, and transmit a signal to the PCB unit. For example, the sensor 40 may be an infrared emitting diode (IRED) and a phototransistor arranged such to detect reflected light of particles in the gas.

[0051] A filter 44 is disposed within the filter media compartment 32. The filter media compartment 32 being square or rectangular in section, and the filter 44 complementarily shaped to provide a fluid-tight seal at an interface between outer surfaces of the filter 44 and inner surfaces of the sides of the filter casing 16. The filter 44 may be partially compressed with resiliency of the materials providing the fluid-tight seal, and / or an adhesive or gasket may be disposed at the interface. Consequently, suction from the vacuum source of the smoke evacuation unit provides a suction path from the suction tube and through the inlet 24 and the filter 44 of the filter media compartment 32 to be discharged through the outlet 22.

[0052] The filter 44 may be formed from a plurality of filter stages or layers, also referred to as a filter stack. The filter stages are generally formed from fibrous or porous materials to remove particulates such as dust, pollen, mold, and bacteria from the surgical smoke. One or more of the filter stages may include differing materials or of differing construction so as to filter the smoke passing therethrough in differing manners. A first filter stage may be a prefilter or prefilter assembly 46 to be described. A second filter stage 48 may be an ULPA filter, for example,a pleat pack of approximately forty pleats and being between one and two inches in thickness. The pleat pack may be cardboard tube and glued with spin glue technology. The third filter stage 50 may be a charcoal filter including a sorbent or catalyst to remove odors from gaseous pollutants such as volatile organic compounds or ozone. A fourth filter stage (not shown) may be a postcarbon filter to separate the third layer 50 from the exterior.

[0053] The liquid collection compartment 34 is disposed below or beneath the filter media compartment 32. The liquid collection compartment 34 may also be referred to as a sump, basin, fluid trap, or the like. FIG. 3 shows a partition wall 52 or a barrier separating the liquid collection compartment 34 from the filter media compartment 32. The partition wall 52 may extend from the real’ side 20 of the housing 12. The illustrated embodiment shows the partition wall 52 extending horizontally therefrom, but alternatively the partition wall 52 may be tapered and / or angled. The partition wall 52 may extend from the rear side 20 by 50, 60, 70, or 80% or more of the length or depth of the housing 12. The position and orientation of the partition wall 52 provides for the liquid collection compartment 34 extending nearly an entirety of the length or depth of the housing 80, thereby maximizing its liquid capacity. In particular, the sectional elevation view of FIG. 3 shows the liquid collection compartment 34 effectively extending from an inner side of the cover 14 to the rear side 20 of the housing 12. In certain embodiments, the liquid collection compartment 34 may have a liquid capacity of 100, 150, 200 or more milliliters (mL) of liquid. A sorbent 54, such as one or more pieces of foam media or super-absorbing fiber or polymer, may be disposed within the liquid collection compartment 34 to limit or eliminate sloshing of liquid therein. The sorbent may include an antimicrobial agent to limit or prevent odors, and / or a reagent configured to change color when saturated with liquid.

[0054] The prefilter assembly 46 may be disposed within the filter media compartment 32. The filter 44 is disposed between the prefilter assembly 46 and the outlet 22. The sensor assembly 36 may be disposed between the inlet 24 and the prefilter assembly 46 such that the sensor 40 detects particulates within the surgical smoke before encountering the prefilter assembly 46.

[0055] With concurrent reference to FIG. 4, the prefilter assembly 46 may include a frame 56, and prefilter media 58 coupled to the frame 56. The frame 56 defines one or more windows 60, and the prefilter media 58 positioned to cover the windows 60. The frame 56 may be secured to the housing 12 through any suitable joining means, for example, welding, gluing,clamping, or the like. FTG. 3 shows a lower edge of the frame 56 coupled to a distal end of the partition wall 52, and remaining edges of the frame 56 coupled to a lip disposed on an inner surface of the filter casing 16. A flange 59 may extend around a perimeter of the frame 56, and the flange 59 is secured to the lip of filter casing 16. The flange 59 may be formed at a front end of the frame 56, i.e., closer to the inlet 24, and a rear surface of the flange 59 is secured to the filter casing 16, such as through ultrasonic welding.

[0056] To ensure consistent positioning of the frame 56 within the filter casing 16, the frame 56 may include one or more ribs 61 disposed on an exterior surface of one or more sides of the frame 56. As best shown in FIG. 4, the ribs 61 are positioned rearwardly to the flange 59 on the top panel of the frame 56, and a similar arrangement may be provided on a bottom panel of the frame 56. The top panel and the bottom panel of the frame 56 are sloped, as to be described in more detail, and the ribs 61 provide a flat-on-flat interface between the top panel of the frame 56 and filter casing 16, and the lower side of the frame 56 and the partition wall 52. The ribs 61 act as locating features to provide a consistent fit of the frame 56 prior to securing the frame 56 within the housing 12. While the top panel of the frame 56 need not be sloped, doing so in conjunction with the ribs 61 provides symmetry for ease of assembly. In other words, the frame 56 may be installed within the housing 12 in one of two orientations without the need for orientation features. With the side panels of the frame 56 being parallel to the inner surfaces of the filter casing 16, additional ribs are not necessary.

[0057] The prefilter media 58 is secured to the frame 56. The frame 56 may include an interior rim 67 associated with each of the top, bottom, and side panels. The interior rim 67 may define a portion of the windows 60. A bonding face 63 may be recessed slightly from the interior rim 67 such that the interior rim 67 functions as a standoff. The bonding face 63 being recessed accommodates a thin layer of adhesive to be applied, thereby providing a flat perimeter seal about an entirety of the windows 60. In a nonlimiting example, the recess may be approximately sixty thousandths of an inch in thickness.

[0058] As mentioned, at least the bottom panel of the frame 56 is sloped for reasons to be described. The prefilter media 58, however, may be a rectangular pad as generally represented in FIG. 4. To ensure positioning of the prefilter media 58 and perimeter seal therethrough, the frame 56 may include one or more ridges 72 defining channels 70 therebetween providing a liquid guide 62 therebetween. The ridges 72 are disposed on an inner surface of at least the bottom panelof the frame 56, and, optionally, on an inner surface of the top panel of the frame 56. Upper surfaces of the ridges 72 may be oriented substantially perpendicular to the bonding face 63. As shown, the ridges 72 may taper in a rearward direction towards the bonding face 63 in a manner complementary to the extent of slope of the bottom panel. As a result, with a perimeter of the rear side of the prefilter media 58 secured to the bonding face 63, a lower surface of the prefilter media 58 rests upon the upper surfaces of the ridges 72. Optionally, adhesive may be applied to the upper surfaces of the ridges 72.

[0059] In a first variant, it is contemplated that the prefilter media 58 may be sized approximately to the largest perimeter of the frame. In such a variant, the material of a rear portion of the prefilter media 58 is effectively compressed by the slope surface. The ridges 72 may or may not be present in the variant. In still another variant, top and / or a bottom of the prefilter media 58 may be cut on an angle complementary to the slope of the top and bottom panels of the frame 56.

[0060] The frame 56 may include one or more struts 57 extending between the sides. The struts 57 and the sides of the frame 56 define the windows 60. The struts 57 provide structural support for the prefilter media 58 against forces associated with the suction being drawn through the filter assembly 10. FIG. 4 shows two of the struts 57 oriented in a cruciform arrangement, but any number and orientation of struts 57 are contemplated so as to provide the support while minimizing decrease in the suction capacity of the filter assembly 10.

[0061] The prefilter media 58 is treated or formed with a coalescing material, in particular a coating that is repellant to liquids, such as a hydrophobic or oleophobic coating, a coating of per- and polyfluoroalkyl substances (PFAS), or the like. The prefilter media 58 may be a mesh-like perforated structure or a mesh or lattice-like braid / fabric. Upon contact with the prefilter media 58, the liquid is promoted to agglomerate or coalesce on or within the prefilter media 58 rather than pass therethrough. The denser liquid molecules descend along an outer surface of the prefilter media 58 into the liquid collection compartment 34 under the influence of gravity. More specifically, the liquid molecules descend along an outer surface of the prefilter media 58 and onto the liquid guide 62. The sloped surface of the liquid guide 62 directs the separated liquid into the liquid collection compartment 34. In particular, the separated liquid descends into the channels 70 spaced apart from the bottom of the prefilter media 58. In instances where a volume of fluid may accumulate at a level above the partition wall 15, the frame 56 may include a barrier 69 extending upwardly from the bottom panel to enhance the overall liquidcapacity of the filter assembly 10. In other words, the liquid level must also crest the barrier 69 before potentially soaking through the prefilter media 58 and into the filter stack 44.

[0062] The gas of the surgical smoke passes through the prefilter media 58 and into the filter 44 of the filter assembly 10. Referring again to FIG. 3, the prefilter assembly 46 is spaced apart from the filter stack 44. In particular’, a rear’ of the frame 56 is separated from the second filter stage 48 of the filter stack 44 by a void space 55 such that the frame 56 acts a spacer to be described in further detail. As mentioned, the second filter stage 48 may be pleated, and the void space 55 is designed to permit the gas to expand to utilize a maximum surface area of the second filter stage 48, thereby maximizing the efficiency of the second filter stage 48. Exemplary embodiments include the void space 55 having a dimension in the direction of flow (SR) of between 2 and 25 millimeters (mm), and more particularly within the range of approximately 5 to 8 mm. Smaller dimensions may be preferable for compact design, whereas larger dimensions may help avoid contamination of the filter stack 44 with any liquid that may pass through the prefilter assembly 46.

[0063] Referring now to FIG. 5, another embodiment of the filter assembly 10, also referred to herein as a filter insert, is shown in longitudinal section. In many respects, the embodiment depicted in FIG. 5 is the same as the embodiment previously discussed with like numerals indicating like components. The filter insert 10 includes the housing 12 with an outlet 23 and an inlet 25. The outlet 23 and the inlet 25 may be male fittings, as shown, configured to be coupled with suction tubing or flexible or rigid conduit, or may be the outlet 22 and / or inlet port(s) previously discussed. The filter insert 10 may be for filtering surgical smoke as previously discussed, or flue gas or other gaseous byproducts.

[0064] When the flue gas enters the filter insert 10 through the inlet 25 in the flow direction (SR), the flue gas passes a separation element 58 of the first filter stage 46, e.g., the prefilter assembly. In one example, the separation element 58 is the prefilter media previously discussed configured to cause the liquid to agglomerate or coalesce, and descend along an outer surface thereof. The separation element 58 is connected in a frame within the housing 12, for example, the frame 56 depicted in FIG. 4. The separated liquid is conveyed via the liquid guide 62 to the liquid collection device 34 or compartment. The first filter stage 46 is followed by the second filter stage 48, which may be separated from the first filter stage 46 by a spacer 64 attached to the frame 56. The third filter stage 50 is located downstream of the second filter stage 48. Thethree filter stages 46, 48, 50 are spatially separated from the liquid collection device 34 hy a partition wall 52. The liquid collection device 34 may extend over the entire longitudinal axis and has a correspondingly large liquid absorption capacity.

[0065] FIG. 6 shows a variant of the filter insert 10 including the insert housing 12, the inlet 25, and the outlet 23. Downstream of the separation element 58 of the first filter stage 46 is the second filter stage 48, and the third filter stage 50. The separation element 58 has an inclination angle against or opposite to the flow direction from the inlet 25 to the outlet 23 to allow the separated liquid to drip off. The liquid drips into the liquid collection device 34, which is located upstream of the three filter stages 46, 48, 50. Furthermore, the liquid separated by the separation element 58 is guided by the liquid guide 62 into the liquid collection device 34. The partition wall 52 separates the liquid collection device 34 from the second filter stage 48 and the third filter stage 50. Furthermore, the frame 56 surrounds the separation element 58, and the spacer 64 separates the first filter stage 46 from the second filter stage 48. The liquid is guided via the frame 56 as a liquid guide 62.

[0066] FIG. 7 shows in longitudinal section a variant of the filter insert 10 including the insert housing 12, the inlet 25 and the outlet 23. Here, the separation element 58 is secured in the frame 56, which secures a second separation element 66, and the spacer 64 for spacing the separation element 66 from the second filter stage 48. The second separation element 66 differs in its design from the first separation element 58. The liquid is guided through the frame 56. The liquid guide 62 directs the liquid from the first and second separation elements 58, 66 and into the liquid collection device 34. The liquid collection device 34 is separated by the partition wall 52 from the second filter stage 48 and the third filter stage 50. The liquid is guided via the frame 56, which serves as the liquid guide 62.

[0067] FIG. 8 shows, in a longitudinal section, an embodiment of the first filter stage 46 in which the separation element 58 is mounted in the frame 56. The frame 56 includes a spacer 65 at each of its opposite ends and configured to be coupled to the housing 12. The spacer 65 may be clips, detents, rails, or the like. The separated liquid is guided via the liquid guide 62 into the liquid collection device 34. The liquid collection device 34 has a storage medium 54 (e.g., a sorbent), which absorbs the liquid, as well as a cover 68 to prevent contamination of the separated liquid from the subsequent filter stages.

[0068] FIG. 9 is a longitudinal section view of a variant the first filter stage 46. The separation element 58 is in the frame 56, with the frame 56 forming spacers 64 at opposite ends of the separation element 58.

[0069] FIG. 10 is a partial front view of a variant of the frame 56 with the separation element 58. The frame 56 has a frame elevation 74 to prevent backflow of separated liquid. The frame 56 is fixed to an insert housing 12. The liquid guide 62 has adjacent guide channels 70 for discharging the liquid from the separation element 58 into a liquid collection device 34 (not shown in FIG. 10). The surfaces of the guide channels 70 facing away from the liquid collection device 34 are angled to the flow direction (SR) so that the liquid flows by gravity through the guide channels 70 into the liquid collection device 34.

[0070] FIG. 11 shows a sectional view of a frame 56 with the separation element 58, wherein the liquid guide 62 has adjacent guide channels 70 that direct the separated liquid into the liquid collection device 34 (not shown in FIG. 11). Furthermore, the frame 56 forms two spacers 64.

[0071] FIG. 12 shows a longitudinal section of another embodiment in which the filter insert 10 is approximately ring-shaped around a ring axis and has two separation elements 58 each held in a frame 56. The frame 56 each have a liquid guide 62, via which separated liquid is fed into a liquid collection device 34. The liquid collection device 34 is formed by the frames 56 and a part of an insert housing 12. The frames 56 also function as partition wall 52 for maintaining separation of the liquid from the second and third filter stage 48, 50. Furthermore, the frames 56 serve as the spacers 64 to space the separation elements 58 from the second and third filter stages 48, 50. In the embodiment, the flow direction (SR) of the fluid is through an inlet 25 into the filter insert 10 axially into the ring of the filter insert 10 and approximately radially through the separation elements 8, the subsequent filter stages 48, 50, and an outlet 23 from the filter insert 10.

[0072] In an alternative embodiment, the separation element 58 may be arranged be at least essentially ring-shaped. In another embodiment, a filter insert 10, similar to FIG. 12, may be mirror- symmetrical to a plane running vertically through the inlet 25, so that this embodiment, in contrast to the fourth embodiment, comprises two second filter stages 48 and two third filter stages 50.

[0073] FIG. 13 shows another embodiment of a filter insert 10, wherein the partition wall 52 separates the liquid in the liquid collection device 34 from the subsequent second and thirdfilter stage 48, 50. Unlike the embodiment of FIG. 5, the partition wall 52 also serves as the spacer 64 to keep the second filter stage 48 spaced at a distance downstream in the flow direction SR at a distance.

[0074] All embodiments and representations shown in the figures can contain the storage medium 54 in the liquid collection device 34.

[0075] Several embodiments have been discussed in the foregoing description. However, the embodiments discussed herein are not intended to be exhaustive or limit the filter assembly to any particular form factor. The terminology which has been used is intended to be in the nature of words of description rather than of limitation. The invention is not limited to one of the previously described embodiments but can be modified in many ways. All features and advantages arising from the claims, the description, and the drawings, including structural details, spatial arrangements, and procedural steps, can be essential to the invention both individually and in various combination. The use of the treatment device can, in addition to medical, especially surgical, interventions, also include cosmetic and other, even non-invasive procedures or treatments in which a thermal effect is achieved. The thermal effect can also be generated by a mechanical tool, such as the use of surgical motors in the field of orthopedics or traumatology for performing sternotomies.

[0076] Further inventive aspects of the present disclosure are made with reference to the following exemplary clauses:

[0077] Clause 1 - A filter insert for a flue gas filter, the filter insert comprising: an insert housing with an inlet and an outlet, which are connected so as to allow fluid flow, at least two filter stages arranged between the inlet and the outlet, characterized by a first of the filter stages, which comprises: a liquid separator and has a separation element; a liquid collection device, which, in use, is arranged lower than the liquid separator and is spatially separated from a second of the filter stages; a liquid guide configured to guide liquid from the separation element into the liquid collection device; and a spacer configured to position the first filter stage at a distance from the second filter stage that is downstream in the flow direction.

[0078] Clause 2 - The filter insert of clause 1, further comprising a third filter stage, which is downstream of the second filter stage in a flow direction and is configured differently from the first filter stage and differently from the second filter stage, wherein the liquid collection device is spatially separated from the third filter stage.

[0079] Clause 3 - The filter insert of clause 1 or 2, wherein the second or the third filter stage is designed as a particle filter or as an adsorber.

[0080] Clause 4 - The filter insert of any one of clauses 1-3, wherein the separation element is designed as a coalescer for the coagulation of liquid droplets.

[0081] Clause 5 - The filter insert of any one of clauses 1-4, wherein the separation element is designed as a hydrophobic sieve.

[0082] Clause 6 - The filter insert of any one of clauses 1-5, wherein the separation element is inclined counter to the flow direction.

[0083] Clause 7 - The filter insert of any one of clauses 1-6, wherein the first filter stage comprises the spacer.

[0084] Clause 8 - The filter insert of any one of clauses 1-7, wherein the first filter stage is arranged at a distance of 2 mm to 25 mm from the second filter stage.

[0085] Clause 9 - The filter insert of any one of clauses 1-8, wherein the insert housing has an intermediate wall that is impermeable to liquid, which is arranged between the liquid collection device and the second filter stage.

[0086] Clause 10 - The filter insert of clause 9, wherein the intermediate wall adjoins the insert housing on both sides.

[0087] Clause 11 - The filter insert of any one of clauses 1-10, wherein the liquid collection device has a cover at the end facing the second filter stage.

[0088] Clause 12 - The filter insert of any one of clauses 1-11, wherein the liquid guide extends into the liquid collection device.

[0089] Clause 13 - The filter insert of any one of clauses 1-12, wherein the liquid guide is formed by a frame surrounding the separation element.

[0090] Clause 14 - The filter insert of any one of clauses 1-13, further comprising a further filter stage designed as a liquid separator, which is upstream of the second filter stage in a flow direction and has a further separation element and a liquid guide, which is designed to guide liquid from the further separation element into a liquid collection device.

[0091] Clause 15 - The filter insert according to clause 14, wherein the separation element of the first filter stage is designed as a coalescer for the coagulation of liquid droplets and the further separation element of the further filter stage is designed as a hydrophobic sieve.

[0092] Clause 16 - A flue gas filter, with a filter inlet and a filter outlet and a filter chamber in the flow direction between the filter inlet and the filter outlet, wherein the filter insert according to any one of the clauses 1-15 is arranged in the filter chamber in such a way that, in use, the flue gas flowing into the flue gas filter flows through the filter insert.

[0093] Clause 17 - Treatment device comprising; a tool that is intended to act thermally on a human or animal body, in particular for separating organic material; a flue gas extraction device, wherein the flue gas extraction device comprises a suction nozzle arranged adjacent to the tool in such a way that flue gases released during the thermal action are drawn into the flue gas extraction device through the suction nozzle, and wherein the flue gas extraction device comprises a flue gas filter for filtering the flue gases, characterized in that the flue gas filter comprises the filter insert according to any one of clauses 1 to 15.

[0094] Clause 18 - Use of a flue gas filter in a therapeutic, in particular surgical, field, wherein the flue gas filter comprises the filter insert according to any one of clauses 1 to 15.

[0095] Clause 19 - A filter assembly for a surgical smoke evacuation unit, the filter assembly comprising: a housing defining an inlet and an outlet positioned to provide a suction path through the filter media compartment; a filter disposed within the filter media compailment and configured to filter surgical smoke; and prefilter media disposed within the filter media compartment between the inlet and the filter, wherein the prefilter media is treated or formed with a coalescing material.

[0096] Clause 20 - A filter assembly for a surgical smoke evacuation unit, the filter assembly comprising: a housing comprising a partition within an enclosure that separates a liquid collection compartment positioned below a filter media compartment, wherein the housing defines the inlet ports and an outlet positioned to provide a suction path through the filter media compartment; a filter disposed within the filter media compartment and configured to filter surgical smoke; and prefilter media disposed within the filter media compartment between the one the inlet and the filter, wherein the prefilter media is treated or formed with a coalescing material.

[0097] Clause 21 - The filter assembly of clause 19 or 20, and further according to any one of claims 1-24.

[0100] Clause 22 - The filter assembly of clause 19 or 20 and further according to one of clauses 1-18.

Claims

CLAIMS1. A filter assembly for filtering smoke, the filter assembly comprising: a housing comprising a partition wall separating a liquid collection compailment below a filter media compartment within the housing, wherein the housing defines an inlet and an outlet in fluid communication to provide a suction path through the filter media compartment; a filter disposed within the filter media compartment; and prefilter media disposed positioned between the inlet and the filter, wherein the prefilter media is treated or formed with a coalescing material, wherein the prefilter media is positioned above the liquid collection compartment such that liquid coalescing on the prefilter media is configured to descend into the liquid collection compailment under influence of gravity.

2. The filter assembly of claim 1, further comprising a prefilter assembly disposed within the housing and comprising a frame defining a window, wherein the prefilter media is sealed to the frame to cover the window.

3. The filter assembly of claim 2, wherein the frame is sealed to the housing, optionally, through ultrasonic welding.

4. A filter assembly for filtering smoke, the filter assembly comprising: a housing providing an enclosure and defining an inlet and an outlet in fluid communication to provide a suction path through the enclosure; a filter disposed within the enclosure; and a prefilter assembly disposed within the enclosure and positioned between the inlet and the filter, wherein the prefilter assembly comprises a frame is secured to the housing and defining a window, and prefilter media sealed to the frame to cover the window, and wherein the prefilter media is treated or formed with a coalescing material.

5. The filter assembly of claim 3 or 4, wherein a filter casing of the housing comprises a lip, and wherein the frame comprises a flange secured to the lip.

6. The filter assembly of any one of claims 3-5, wherein the frame further comprises a lower panel, an upper panel, and opposing side panels, and wherein a portion of the flange extending from the lower panel is secured to an end of the partition wall.

7. The filter assembly of claim 6, wherein the lower panel of the frame is sloped downwardly away from the filter to provide a liquid guide to the liquid collection compartment.

8. A filter assembly for filtering smoke, the filter assembly comprising; a housing providing an enclosure and defining an inlet and an outlet in fluid communication to provide a suction path through the enclosure; a filter disposed within the enclosure; and a prefilter assembly disposed within the enclosure and positioned between the inlet and the filter, wherein the prefilter assembly comprises a frame defining a window, and prefilter media disposed within the window, wherein the prefilter media is treated or formed with a coalescing material such that liquid coalescing on the prefilter media is configured to descend onto a lower panel of the frame under influence of gravity, wherein the lower panel of the frame is sloped downwardly away from the filter.

9. The filter assembly of any one of claims 6-8, wherein the lower panel of the frame comprises ridges defining channels therebetween, and wherein a bottom of the prefilter media is supported on the ridges.

10. The filter assembly of claim 9, wherein the ridges taper rearwardly in a manner complementarily to the slope of the lower panel.

11. The filter assembly of any one of claims 6-10, wherein the frame further comprises one or more ribs disposed on an exterior surface of the lower panel of the frame.

12. The filter assembly of claim 11, wherein the one or more ribs are positioned rearwardly to the flange.

13. The filter assembly of any one of claims 6-12, wherein the frame further comprises struts extending between one or more of the lower, upper, and side panels, wherein the window is a plurality of windows defined by the struts.

14. The filter assembly of claim 13, wherein the stmts are oriented in a cruciform arrangement.

15. The filter assembly of any one of claims 2-14, wherein the frame further comprises an interior rim defining the window, and a bonding face recessed from the interior rim, and wherein adhesive is disposed on the bonding face such that a flat perimeter seal is provided about the prefilter media.

16. The filter assembly of any one of claims 1-15, wherein the prefilter media is spaced apart from the filter by a void space, and optionally, wherein the void space is within a range of 2 to 25 millimeters.

17. A filter assembly for filtering smoke, the filter assembly comprising: a housing providing an enclosure and defining an inlet and an outlet in fluid communication to provide a suction path through the enclosure; a filter disposed within the enclosure; and a prefilter assembly disposed within the enclosure and positioned between the inlet and the filter, wherein the prefilter assembly comprises a frame defining a window, and prefilter media sealed to the frame to cover the window, wherein the frame is secured the housing so as to provide a void space between the prefilter media and the filter.

18. The filter assembly of any one of claims 1-17, wherein the filter is a filter stack comprising an ultra-low particulate air (ULPA) filter, and, optionally, a charcoal filter, and, optionally, wherein the ULPA filter is pleated.

19. The filter assembly of any one of claims 1-18, wherein the partition wall extends horizontally from a rear side of the housing.

20. The filter assembly of claim 19, wherein the housing comprises a filter casing, and a cover coupled to the filter casing, and wherein the liquid collection compartment extends along nearly an entirety of a length of the filter assembly between the cover and the rear side.

21. The filter assembly of any one of claims 1-20, further comprising a sorbent disposed within the liquid collection compartment.

22. The filter assembly of any one of claims 1-21, wherein the coalescing material is one of a hydrophobic or oleophobic coating, and a coating of per- and polyfluoroalkyl substances (PFAS).

23. The filter assembly of any one of claims 1-22, wherein the prefilter media is a mesh-like perforated structure, a mesh, or a fabric with a latticed braid.

24. The filter assembly of any one of claims 1-23, further comprising a sensor disposed between the inlet and the prefilter media, wherein the sensor is configured to detect particulates within the smoke before the smoke encounters the prefilter media.

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