Design of an Angled Adsorptive Filter Medium for Use in Wiring Applications

Abstract

A media design for modular use in air purification or HVAC systems to remove gaseous contaminants. The design uses variable media length, path length, and contact time to control gaseous contaminant removal and allows for a low MTZ length and low pressure drop. In one embodiment, the design includes a filter module at an angle to the airflow and an air filter mounted within a filter frame. The filter module may include channels oriented at an optimal angle to the airflow to provide the required residence time and pressure drop for a given application.

Description

Background Art

[0001] In recent years, purification of indoor air has become more common because of its impact on the health of building occupants. The EPA (Environmental Protection Agency) defines indoor air quality (IAQ) as "the air quality within and around buildings and structures that is particularly relevant to the health and comfort of building occupants." A decrease in IAQ can lead to headaches, fatigue, reduced concentration, and irritation of the eyes, nose, throat, and lungs. Air quality is also important for various manufacturing processes and equipment within a building. For example, although there are few people in a data center, many servers are sensitive to contaminants in the air. These contaminants are classified into three broad categories: particles, biological, and gas-phase. Although this specification will explain gas-phase contaminants in detail, the uses of the filters described below are not limited thereto. Similarly, although the description refers to "airflow" and "air filters," other fluids may be filtered using the filters described in this specification.

[0002] Gas-phase contaminants originate from numerous indoor and outdoor sources and can have various harmful effects on building occupants and various operations. For example, volatile organic compounds (VOCs) can be found in indoor air emitted from paints, carpets, copy machines / printers, laminate furniture, wood preservatives, thinners, adhesives, permanent markers, cosmetics, and certain aerosols and plastics. Exposure to VOCs can cause symptoms ranging from nausea and headaches to liver and lung damage. Furthermore, building occupants generate CO2, which also needs to be diluted or removed.

[0003] A wide range of gas-phase contaminants can also be found in indoor air from external sources such as exhaust, decaying vegetation, wildfires, industrial manufacturing, water treatment, and chemical plants. The contaminants vary widely from H2S, SO2, and other sulfur-based compounds in pulp and paper mills to SO2, NO x in engine exhaust, and hydrocarbons.

[0004] Furthermore, there are many applications where manufacturing processes or products within a building generate odors and gaseous contaminants that must be removed before the air is exhausted outdoors, such as terpenes in marijuana greenhouses and cultivation facilities.

[0005] To maintain contaminants at acceptable levels, gaseous contaminants may be removed or diluted with relatively clean air. Both have operational and energy implications for the building. For outdoor air to be used for dilution, the outdoor air must be clean. Many urban areas do not have air of sufficient quality and need to be cleaned before it can be used. Furthermore, even if the air is sufficiently clean, it needs to be conditioned (heated, cooled, and / or humidity controlled) before being introduced into the building. Gaseous contaminant removal systems are large, expensive, difficult to install, and costly to maintain. Removal of gaseous contaminants is generally achieved by contacting the air with an adsorbent, absorbent, chemisorbent, photocatalyst, catalyst, or other materials having removal characteristics referred to herein as sorbents. These can be used in combination with each other or in combination with other materials to form an effective filter medium.

[0006] Activated carbon is one of the adsorbents commonly used in IAQ for the removal of gaseous contaminants and exists in several different physical forms including powder, granular, pellet, paper, and honeycomb structures. Activated carbon can be made from a variety of materials including coal, coconut shells, and wood. The starting material and activation process affect the pore structure and pore volume in the final activated carbon product. Most adsorption occurs in mesopores and micropores (less than 50 nm in diameter), and therefore, selecting activated carbon that maximizes the pore volume less than 50 nm is, although not limited to this, a consideration in the overall performance of the medium.

[0007] Mass transfer zone (MTZ) Mass transfer is the term used when removing gaseous contaminants from an air stream using an adsorbent medium. It is not the capacity, rather the length of the MTZ that determines the efficiency and life of the medium, but the length of the MTZ is not commonly used in the industry. This is because it is difficult and time-consuming to measure.

[0008] The final capacity and the length of the mass transfer zone (MTZ) are two related factors when designing an adsorbent system to capture gaseous contaminants. The final capacity refers to the total weight of a specific contaminant that an adsorbent can adsorb, which is the ratio of the weight of the contaminant to the weight of the adsorbent (weight of contaminant / weight of adsorbent). The final capacity is usually measured at high concentrations far exceeding the applicable concentration and varies depending on the combination of each contaminant and the adsorbent. The MTZ is the part of the adsorbent where adsorption occurs actively, and the length of the MTZ depends on the adsorbent (type, amount, structure, etc.) and conditions (face velocity, contaminant, concentration, etc.).

[0009] When using an adsorbent medium with a relatively short depth that is typical or available for most applications, the length of the MTZ can be a more important design element. The depth of the medium should be at least equal to the MTZ in order to provide 100% efficiency. As shown in Figure 1A, the MTZ 21 starts from the inlet 22 of the adsorbent column and moves through the depth of the medium as the adsorbent is consumed. The adsorbent above the MTZ is saturated with a given challenge gas 23 and there is no longer active adsorption. Below the MTZ, there is new adsorbent 25 that the gas contaminants have not yet reached. The breakthrough occurs when the MTZ 21 moves through the entire adsorbent column and the leading edge 2X of the MTZ reaches the end of the adsorbent and can no longer capture gas contaminants. It is the length of the MTZ, rather than the capacity, that determines the efficiency and life of a medium of a specific depth, but most manufacturers still report the medium capacity value of the adsorbent for design purposes. In other words, a large capacity is not necessarily equivalent to efficiency in all situations.

[0010] Background of Further Air Filtration Another factor in the use of gas-phase removal media is the resistance to air flow or pressure drop. Air cleaning is often used in building heating, ventilation, and air conditioning (HVAC) systems. Many HVAC systems do not have fans powerful enough to handle the additional pressure drop, limiting the application of air cleaning in existing systems. Even when the fans are large enough and / or the need for air cleaning was considered in the original design, a large pressure drop can increase energy and operating costs.

[0011] The sorbent material used to capture gas-phase contaminants may be in pellet form. The most widely used commercial carbon filtration systems use a 13-inch deep, square or rectangular 24×24-inch perforated "tray" filled with carbon pellets. Pellet tray modules are highly resistant to air flow, requiring powerful fans in these systems. Additionally, carbon pellet systems generate additional pressure drop and additional space requirements because they emit carbon dust and require downstream particle filters. The pellet trays provide random air flow channels, and the moving air seeks the shortest path through them, leaving some parts of the pellet trays unused or in use. Over time, the pellets are exposed to daily and seasonal temperature and humidity variations and repeated vibrations that lead to the breakdown of granular residues. Eventually, the residues either clog the screen material or exit the module and enter the downstream air flow. The vibrations can also lead to channels or gaps in the loose packing media that allow air containing untreated contaminants to pass through the module. To overcome these problems and the uncertain length of the MTZ, pellet systems for critical applications must be very deep, further increasing the pressure loss.

[0012] In typical applications, the pellet trays are arranged in an angled array to increase surface area and reduce pressure. Since air passes through the shortest path through the pellet bed, the length of the media path is only 1 - 3 inches, which may be shorter than the length required to obtain the MTZ. Further, since the diameter of the pellets is usually 2 - 4 mm, it can be difficult to access the adsorbent at the center of the pellets, especially with the air flow and contact time in a typical system.

[0013] Another form of applying granular or pelleted adsorbent materials, such as activated carbon, is as a layer of a multi-layer media, where the adsorbent material is sandwiched or fixed between multiple layers of breathable media. This media is sufficiently closed and / or the adsorbent is sufficiently bound to prevent dust from moving into the air stream. Typically, this multi-layer assembly has an overall thickness between 1 / 8 inch and 1 / 4 inch, is pleated, and made into assemblies of various depths. This is an effective means of incorporating a reasonable amount of adsorbent into the air stream, but since air passes through the media via the shortest path, the depth required to obtain the MTZ is rarely achieved and the efficiency is usually low.

[0014] One alternative to pellets for capturing VOCs and other gas-phase contaminants is the use of ceramic-bonded activated carbon honeycomb structures. Typically, these have a square grid cross-section, are extruded, dried, fired at high temperature, cut to size, and assembled into modules. These honeycomb structures have the following advantages. · Pressure loss 20 - 70% lower compared to pellet tray modules. · Approximately half the estimated weight of a pellet tray system. · High-speed and effective media contact at up to 6 times the speed of a conventional pelleted carbon bed. · The adsorbent is fully accessible, allowing for shorter MTZ lengths, higher efficiency, and complete utilization of the media. · A dust-free media with a stable structure that eliminates the need for post-filtration.

[0015] The honeycomb module can be of any depth, but in typical HVAC applications, considering space and pressure drop, it is usually arranged in a square or rectangular panel with a nominal 2-inch depth and installed on a flat or angled rack of the system. The 2-inch media has a relatively short path length and is often shorter than the MTZ of certain contaminants. This may result in reduced efficiency for some contaminants or in difficult environments, or unused capacity.

[0016] The effectiveness of this structure is a function of contact / stay time, among other factors. To increase the stay time, the available cross-sectional area may be limited, so the structure is often angled with respect to the air flow to form a "V". This slows down the air flow, increases the stay time, improves efficiency, and shortens the length of the MTZ.

[0017] For example, a duct can have a cross-section of 24×24 inches with a single flat 24×24×2-inch panel of carbon honeycomb structure and an air flow of 2,000 cfm. The media velocity is ~500 fpm. If two of these panels are formed in a "V" within the air flow, each panel is considered to have 1,000 cfm and the media velocity becomes 250 fpm. This slows down the air velocity per panel, resulting in a shorter MTZ length and improved media efficiency.

[0018] The honeycomb channels usually maintain their shape with respect to the flow. Therefore, for air to pass through the structure and continue into the duct, it has to make two sharp turns. This adds pressure loss and is not an efficient use of space to maximize the path length.

[0019] These honeycomb systems are at the forefront of current technology, but it is also possible to improve them, particularly to increase air path length, efficiency, operating life, design, and flexibility of the adsorbent material, reduce turbulence, and improve removal performance. At least currently, carbon honeycombs are very expensive compared to other filter systems and are thus restricted in use to special applications.

[0020] Figure 1 shows one possible filter assembly 50 within an air duct or passage 90 for use with a filter medium. As shown, there is an air flow from left to right. The air flowing from left to right passes through a filter assembly 50 that includes two filter modules 60 (more or less may be possible as shown). The filter module 60 engages, at an attachment end 62, with an attachment sleeve or assembly 80 having a channel 82 sized to receive the attachment end 62, and the filter module 60 and / or the channel 82 may include a seal 84 at a second end, and the seal 84 may also include the attachment sleeve. The seal 84 prevents air passage around the filter assembly 50. Each filter module 60 facing each end 63 abuts with a filter module seal 65 (not showing an actual channel or joint, but rather shown clearly for clarity) that further prevents air passage around the filter assembly 50.

[0021] The filter module 60 may include a frame 64 that contains a filter material 66 therein. The frame and the filter material may be of at least the types described in U.S. Patent No. 3,209,074; U.S. Patent No. 4,620,691; U.S. Patent No. 4,628,386; U.S. Patent No. 4,671,126; U.S. Patent No. 4,790,259; U.S. Patent No. 4,908,634; U.S. Patent No. 5,184,706; U.S. Patent No. 6,574,123; U.S. Patent No. 7,686,869; U.S. Patent No. 7,691,186; U.S. Patent No. 7,708,813; U.S. Patent No. 8,070,861; U.S. Patent No. 8,252,095; U.S. Patent No. 8,252,097; U.S. Patent No. 8,795,601; U.S. Patent No. 8,814,994; U.S. Patent No. 9,764,331; U.S. Patent No. 9,789,494; U.S. Patent No. 9,861,990, and U.S. Patent Application Publication No. 2016 / 0303499, the content of which is incorporated by reference as if fully set forth herein.

[0022] The attachment points between the filter assembly and the duct 70 and between adjacent filter modules 72 can create regions that prevent the passage of air flow. This can result in turbulent flow, an increase in pressure loss, and a non-uniform air flow through the filter assembly 50. Thus, tilting the honeycomb module increases the surface area and reduces the pressure drop compared to the flat module, but the reduction is less linear due to blocked air flow, non-uniform air flow, and changes in direction.

[0023] Also, in many applications, air, liquid, or gas flows through similarly angled structures designed to effect some change (e.g., heating, cooling, washing) through tangential contact with the structure. Examples of this include the coils of an HVAC system, a car radiator, or a carbon honeycomb matrix for air flow.

[0024] Based on the above, there are many issues related to the flow passing through the filter in a wide range of applications. SUMMARY OF THE INVENTION

[0025] Media design for use of modules in air purification or HVAC systems for removing gaseous contaminants. In this design, variable media length, path length, and contact time are used to control gas contaminant removal, and it is possible to suppress the length of the MTZ and keep the pressure loss low. In one embodiment, the configuration includes a filter module angled with respect to the air flow and an air filter mounted within the filter frame. The filter module may include channels angled at an optimal angle with respect to the air flow to provide the residence time and pressure drop required for a given application.

[0026] For clarity, the following will describe in terms of horizontal ducting and air flow. However, in actual applications, the duct may run vertically or diagonally. Additionally, the module itself may be rotated within the duct.

Brief Description of the Drawings

[0027]

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DETAILED DESCRIPTION OF THE INVENTION

[0028] Filter Media Module As shown in FIGS. 2A-2E, 3A, 3B, 4A-4D, 5A, and 5B, the air filter modules 200, 400 may be removably disposed within an air filter system 300 (generally referred to herein as an “air filter”) that may itself be removably disposed within an air duct or passageway 90 that filters the passing air. To maximize the exposure of the filter media 214, 414 to the air flow being filtered and to minimize the pressure drop, the filter modules 200, 400 may be inclined with respect to the air flow. In this case, it is understood that the shortest path for the air flow from the front face (facing the air flow) of the filter module to the back face of the filter module is defined along the lines shown as cross-section lines 2B, 2C, 2D, 2E-2B, 2C, 2D, 2E, and by this line, the air flow path through the channels, described throughout this application, is contrasted with the longer channels.

[0029] For example, channels 212, 212a, 412, 412a passing through filter modules 200, 400 may be oriented parallel to the air flow to minimize the pressure drop through filter modules 200, 400 and increase the path length of the air flow (and thus the exposure of medium 214 to the air flow). In this parallel channel arrangement, the possible path length is defined within the area in channel 212 that is exposed to filter medium 214, is approximately rectangular in FIG. 2C, and further exists between beads 217 in FIG. 2B, thereby allowing a more tortuous path length to pass therethrough. In the embodiments shown in FIGS. 2D, 2E, 5A, and 5B, however, the path length is formed in different shapes and uses serpentine channels to create turbulence in the air flow, thereby creating more air flow that is exposed to the filter medium for the length of the channel and the duration within filter module 200.

[0030] The channels are defined between parallel layers of filter media 214, 414 of the material types defined below. Filter module 200 in FIGS. 2A - 2C has vertically arranged filter medium 214, but within this filter module 200, spacers 216 define the bottom and top of channels 212, 212a and separate the parallel layers of filter medium 214. Spacers 216 can have sizes and heights that meet the design requirements of air filter 300, and considering ease of assembly, designing a filter with some space between multiple layers of filter medium 214 is a simple matter of changing the height / thickness of the spacers. Further, the layer materials of filter media 214, 414 may be of various thicknesses and widths.

[0031] As shown in FIG. 2B, the spacer 216 can be formed of substantially circular beads 217 arranged in parallel rows that direct an air flow across the filter medium 214 to filter compounds within the channel 212 and between the beads 217 in the same column. The beads 217 may have a hemispherical shape or a more flattened cylindrical shape and may be formed of an adhesive or other polymer that cures before application to prevent bonding to adjacent filter medium layers 214 (although such bonding may be desirable in some situations), or may be formed in a manner that engages both sides of the filter medium layer.

[0032] FIG. 2C shows an embodiment in which the spacer 216, which are the individual beads 217, are formed as elongated lines 217a. These elongated lines 217a can better define the channel 212a and encourage less turbulent air flow through the filter module 200. The lines 217a may have a shape with a hemispherical cross-section and may be flattened similar to the beads 217.

[0033] The beads 217 and the lines 217a, 217d, 217e may be combined in the filter module 200 and may be of any shape as long as they promote effective filtration through the filter module 200, such as having a teardrop or similar aerodynamic structure, or may be square. Various paths 212 may be formed between multiple layers of the filter medium 214 or may even be formed between two identical parallel sheets of the filter medium 214.

[0034] The beads 217 or the lines 217a may be made of silicone, acrylic, epoxy, hot melt, or urethane-based adhesives as long as the viscosity of the adhesive allows the formed beads to hold the desired height of the channel. The adhesive can be applied using a hand gun, a fixed nozzle on a moving web sheet, or a programmed bonding machine.

[0035] The selected adhesive may be a hot melt adhesive, which cures quickly, does not contribute to VOCs in the air after curing, and withstands typical HVAC conditions. Examples of such adhesives include Henkel Loctite adhesives (various possible, listed as low VOC or zero VOC), Technomelt 232 hot melt adhesive (ethylene vinyl acetate, EVA), 3M 100% solid hot melt (EVA), or Dow Corning brand silicone hot melt adhesives with reduced VOCs.

[0036] The adhesive may also be minimized to reduce the amount of the adsorbed medium that is blocked / blinded. Also, the channels formed need not be continuous or parallel, and the adhesive functions as a way to keep the adsorption sheet separated and prevent the medium from sagging.

[0037] The spacer 216 may include additives that improve filtration or add properties not included in the filter medium to further improve the filtration process, and thus serves not only for structural purposes but also for filtration purposes.

[0038] Figures 2D and 2E show another embodiment of the filter module 200, where the channels 212d, 212e do not direct the air flow along the shortest path through the filter. Instead, they direct the air flow 232 along a serpentine path having a portion parallel to the air flow 232 and a portion not parallel to the air flow 252. Since the paths y, y’ are such that y > x and y’ > x as shown, they provide additional exposure to the filter medium 214 on a straight-line path through them, thus creating an additional path length. In Figure 2E, the path y’ ends within the filter module and may provide a turbulent zone 252 within the filter module 200 before the air flow is present in the filter module 200. The serpentine channels y and y’ can increase the exposure of the air flow to the filter medium. That is, they increase the path length of the air flow. The serpentine channels y, y’ enable a specific increased path length and medium exposure and can meet the filtration requirements while maintaining the existing basic structure that provides only the filter width x (x is typically 2 inches).

[0039] The filter modules 400 of FIGS. 4A - 4D are similar to those of FIGS. 2A - 2C, except that the filter media layer 414 is the spacer 416 that defines the sides of the channels 412, 412a and is horizontally oriented between the spacers 416 that separate the parallel layers of the filter media 414. As shown in FIG. 4B, the spacers 416 may be substantially circular beads 417 and are formed in parallel rows that direct the air flow across the filter media 414, are within the channel 412, and filter compounds that are between the beads 417 within the same row.

[0040] FIG. 4C shows an embodiment formed as lines 417a having an elongated shape instead of the spacers 416 that are the individual beads 417. These elongated lines 417a can better define the channel 412a and facilitate less turbulent air flow through the filter module 400.

[0041] The filter modules 200, 400 may be combined side - by - side or end - to - end to extend their length, or since such media tend to sag, they may include intermediate supports within them to prevent sagging of the filter media 214, 414.

[0042] FIGS. 5A and 5B show examples that may be required in an embedded or limited - space situation. FIG. 5A shows an angled filter module 500 having channels 512 defined by beads or lines that can be used with the fixture 80. This can result in a greater pressure drop and direct air flow 572 through regions with less air flow through the filter module 500, but may prove beneficial in some filtering environments.

[0043] Figure 5B shows an angled filter medium that can be used in some of the more general frame racks, including a sleeve 80 that is not offset from each other and is shaped to receive rectangular filter modules. In such a configuration, channel 512a can be angled between spacers 514b. The medium can be oriented vertically or horizontally, but in either case, the angle of channel 512a can increase the path length, but may also create a more turbulent region 572b where channel 512a is not of uniform height.

[0044] To achieve more surface area exposure of filter media 214, 414 to the air flow, the filter module may be tilted at an angle α with respect to the air flow, which may be 12 degrees, 18 - 21 degrees, 30 degrees, or other angles as shown in FIGS. 3A and 3B. In FIGS. 3A and 3B, the stacked filter module 200 includes an air filter 300 within an air passage 90. In such an air filter 300, the low - flow region 372 near the seam 330 is minimized compared to similar regions 70, 72 in conventional filters. The seam 330 can be welded, adhered, or sealed to prevent air flow through it, and each filter media can have one end facing the air flow and the other end away from the air flow. The seam 330 may be covered by triangular or other suitable - shaped channels 818 of the filter frame 810 (FIGS. 8A and 8B), and these channels 818 may be at any filter seam 330, but preferably at the "point" where the filter faces. The filter media 214 shown in FIGS. 3A and 3B is shown in a vertical configuration, but it should be understood that it is also possible in the horizontal configurations of FIGS. 4A - 4D.

[0045] Accordingly, shown is a flat filter medium with spacers forming channels, although the filter medium 600 can be pleated as shown in FIGS. 6A - 6C. In such a filter medium 600, alternating pleat peaks 620 form channels 610 for air passage therethrough, and the filter medium 600 can be oriented horizontally or vertically to create channels 610 therethrough.

[0046] The pleated filter medium 600 may be formed having a uniformly cut facing edge 630 and trailing edge 640 as shown.

[0047] Another formation of such a pleated filter 600 may include folding a generally rectangular filter medium 650 and folding it in alternating directions along fold lines 660 to result in an angled medium 650 as shown in FIG. 6C. The pleated filter medium 600 may be formed from a parallelogram - shaped flat material to form different desired channel configurations.

[0048] FIG. 6D shows stacking pleated filters 600 in a way that the pleated filter 600 can form an air filter, with multiple layers of pleated filter media separated by spacers 640 to create channels therethrough.

[0049] FIG. 6E shows an alternative method of forming channels 612f within a filter medium 614f using fold lines 617f that act as spacers between filter media. As shown, the fold lines 617f separate multiple layers of media 614f and add spacers 617f that themselves have filtering characteristics.

[0050] In another configuration, activated carbon paper is corrugated and then the corrugated carbon media are stacked / adhered at an angle to achieve a similar resulting channel structure through the corrugated channels. Yet another configuration for creating channels through a filter medium can involve using a honeycomb structure.

[0051] To protect the media with minimal movement, a mesh or screen may be used to hold the filter media in place.

[0052] To maintain the spacing between multiple layers of filter media, a toothed spacer (similar to a toothed comb) or a preformed mesh with channels may be used to separate the layers and maintain the spacing between them, and strength may also be added.

[0053] Calculation and testing of the filter module / media

[0054] When the width of the module frame 220 is 2 inches and the angle α = 20 degrees (approximate angle of the current configuration of three modules in a 24×24 duct), the horizontal air path length is H or 5.85 inches (see Equations 1 - 4). This is approximately three times the path length (2 inches) at the current media exposure. JPEG0007703851000001.jpg42164

[0055] Tests have shown that a decrease in the face velocity through the media has a much greater impact on the MTZ length than an equivalent decrease in the contaminant concentration, which improves efficiency. For example, the MTZ length at 1 ppm H2S at 500 feet per minute is 4.8 inches compared to 2.8 inches at 100 feet per minute. In contrast, at 0.1 ppm H2S and 500 feet per minute, i.e., with a 10 - fold decrease in concentration, the MTZ length only decreases to 4.6 inches. After 120 days, when examining the efficiency of a specific honeycomb - structured media containing 1 ppm H2S, the efficiency was measured to be 45% at 500 feet per minute, 90% at 250 feet per minute, and 100% at 100 feet per minute.

[0056] Additional tests demonstrated that the pressure drop through an air filter with channels oriented perpendicular to the filter face and attached at a 45-degree angle is approximately twice that of the same filter attached vertically for the same air volume. When the same medium was assembled into an angled filter with channels parallel to the air flow, the pressure drop returned to the original vertical pressure drop.

[0057] Filter media material The filter media 214,414 can be any effective media, including those described herein. The filter media 214,414 may be an activated carbon paper media made of 50 wt% coconut or wood activated carbon (for IAQ applications, the honeycomb structure is 30 - 60 wt% carbon). Coconut carbon can be used for VOC adsorption because it has a larger micropore volume compared to wood-based carbon used in honeycomb structures. The manufacturing method of the activated carbon paper provides flexibility with respect to additives for target-specific challenge gases or the addition of alternative adsorbents such as zeolites, molecular sieves, MOFs, etc. In contrast, honeycomb structures are difficult to make with many adsorbents and are restricted to additives compatible with the binder system.

[0058] Carbon paper media provides easy formability and operability, which are not very available in honeycomb structures and corrugated materials. The channel dimensions can be easily adjusted, and by varying the interlayer spacing and the angle of the path length or the channel angle, it is possible to reduce the MTZ length or the pressure drop. In contrast, honeycomb structures require expensive dies for each configuration (wall thickness and channel dimensions). Furthermore, it is possible to combine papers with different adsorbents or properties in the same module.

[0059] Another alternative for the activated carbon media, as shown in U.S. Patent No. 6,355,330, U.S. Patent No. 5,147,722, and U.S. Patent No. 5,792,513, which are incorporated by reference as if fully set forth herein, is to use a polymer such as polypropylene (PP) or polyethylene (PE) to bind the activated carbon granules or powder and sandwich them between thin nonwoven media. In such media, the central media is activated carbon in excess of 80% by weight, and the polymer binder does not block the pores of the activated carbon.

[0060] Filter material with a support frame member Figures 7A and 7B show a filter module 700 having a filter media 710 supported on a structure that can include a support beam 720. The filter media 710 includes individual sheet members 710 attached on the beam 720. The spacers 730 serve to ensure a consistent spacing between the media 710 and to form air channels 740 of consistent cross-section.

[0061] Figures 7C and 7D show alternative embodiments for the support structure. Figure 7C shows a beam 720 and a spacer 730 attached through the center of the member 710. Figure 7D shows a beam 720a and a spacer 730a attached to the opposing edges of the member 710a.

[0062] The configurations of Figures 7A - 7D can attach the media 710 in a horizontal direction (as shown) or a vertical direction, as shown in Figure 7E, which shows a filter media 710e, a beam 720e, and a spacer 730e.

[0063] Figures 8A and 8B show a filter frame 800 for use with the filter modules 200, 400 described herein. The filter frame 800 includes a removable particle filter 820 and the air filter 300 already described. The particle filter 820 can filter particles so that the carbon adsorbent filters 200, 400 are not clogged with particles. The channel 818 is attached to an upright frame member 816 mounted perpendicular to the air flow, guides the air flow from the seam 330, holds the individual modules 200 together, and forms a gas phase removal portion of the entire air filter 300.

[0064] Furthermore, banks of the filter modules 200, 400 can be combined in series within the air flow and / or combined with other systems or technologies to achieve the required air quality.

[0065] Although the invention has been described with reference to the above embodiments, those skilled in the art will understand that various changes or modifications can be made without departing from the scope of the claims.

Claims

1. A filter media module for use in a fluid filter that filters contaminants from an air stream, comprising: a filter frame; and a filter media removably provided within the filter frame and defining a shortest path through the filter frame, wherein the filter media includes channels through which the air stream passes, each channel being formed by a spacer that separates the filter media and defining a channel path length longer than the shortest path, and consisting of a portion parallel to the air stream and a portion not parallel to the air stream, and the channels terminate in front of the rear end of the filter media module and provide a turbulent zone within the filter media module. The filter media module is characterized by this.

2. The filter media module according to claim 1, wherein the filter media includes a plurality of layers of filter media.

3. The filter media module according to claim 2, wherein the spacer has an elongated shape.

4. The filter media module according to claim 2, wherein the spacer is an adhesive.

5. The filter media module according to claim 4, wherein the adhesive connects the plurality of layers of filter media.

6. The filter media module according to claim 4, wherein the adhesive does not emit VOCs.

7. The filter media module according to claim 2, wherein the filter media includes an activated carbon material.

8. The filter media module according to claim 7, wherein the activated carbon material includes carbon granules or powder provided between non-woven media.

9. The filter media module according to claim 2, wherein the plurality of layers of filter media are stacked horizontally.

10. The filter media module according to claim 2, wherein the plurality of layers of filter media are stacked vertically.

11. The filter media module according to claim 1, wherein the angle of the filter media with respect to the air stream is 18 to 21 degrees.

12. The filter media module according to claim 1, wherein the filter media includes a pleated filter material.

13. a filter frame; and A plurality of filter media modules including a filter medium removably provided within a filter frame and defining a shortest path through the filter frame, the filter medium including channels through which air flows, each channel being formed by a spacer separating the filter media and comprising a path having a portion parallel to the air flow and a portion not parallel to the air flow defining a channel path length longer than the shortest path, the channels terminating in front of the rear end of the filter media module and providing a turbulent zone within the filter media module, The plurality of filter media modules are connected to each other, characterized by an air filter.

14. A filter frame, Including a filter media module including a filter medium removably provided within a filter frame and defining a shortest path through the filter frame, The filter medium includes channels through which air flows, each channel being formed by a spacer separating the filter media and comprising a path having a portion parallel to the air flow and a portion not parallel to the air flow defining a channel path length longer than the shortest path, the channels terminating in front of the rear end of the filter media module and providing a turbulent zone within the filter media module, characterized by an air filter.

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