DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Objections
Claims 9 and 10 are objected to because claim 9 is labeled “Currently Amended” while claim 10 is labeled “Original” when both claims should have the status identifier “Withdrawn” because the claims are non-elected. Note that failure to include the proper status identifier in future responses may result in a notice of non-compliance.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 3 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 3 recites:
3. The air filter assembly (10) as claimed in claim 1, wherein the filter frame (20) is an air bypass leak proof frame, wherein the leakproof frame is configured to form an airtight seal with the single filter frack to prevent air bypass. Emphasis added.
Claim 3 is indefinite because “the leakproof frame” lacks antecedent basis, while it is unclear whether “the leakproof frame” refers to the “filter frame (20).” To overcome this rejection, claim 3 could be amended to read:
3. The air filter assembly (10) as claimed in claim 1, wherein the filter frame (20) is an air bypass leak proof frame, wherein the air bypass leak proof
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1–3, 6 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Lans, US 2012/0272632 A1 in view of Fukuda et al., US 4,181,513.
Regarding claim 1, Lans teaches an air intake that can be used to filter ventilation air for a building. See Lans [0002], [0016]–[0017]. The air intake reads on the claimed “air filter assembly.”
The air intake comprises a particle filter assembly, which reads on the claimed “filter frame.” See Lans Figs. 3, 4, [0041]. The particle filter assembly has a sigma convex shape, as claimed, which is formed by the outline of two adjacent filter pockets of the back filter unit 7, as seen in Figs. 3 and 4. The particle filter assembly also has a V-convex shape, as claimed, as seen by adjacent sections of back filter unit 7 in Figs. 3 and 4. The particle filter assembly is configured to accommodate front filter unit 6 and back filter unit 7 (“at least two frames”) using a “frame on frame design,” as claimed, because front filter unit 6 is mounted within the back filter unit 7. See Lans Figs. 3, 4, [0051].
The particle filter assembly comprises the front filter unit 6, which reads on the “pre-filter” because it is upstream of the back filter 7. See Lans Figs. 3, 4, [0051]. The front filter unit 6 is capable of filtering coarse dust particles of a predefined size, as claimed, because it is the upstream filter in the filter assembly with the filter assembly being used to filter particles from air. Id. at [0058]; MPEP 2114, subsection IV (functional claim language that is not limited to a specific structure covers all devices that are capable of performing the recited function).
The particle filter assembly also comprises the back filter 7, which reads on the “fine filter.” See Lans Figs. 3, 4, [0051]. The back filter 7 is capable of filtering bacteria, pollen, fine dust and aerosol of predetermined size from air, as claimed, because the back filter 7 can have the same efficiency and dust holding capacity as the front filter 6 and the filter assembly is configured to remove unwanted contaminants, such as dust, pollen, mold and salt particles from air. Id. at [0002], [0011]; MPEP 2114, subsection IV.
Each of the two stage filter media (the front filter unit 6 and the back filter unit 7) comprise a sigma convex shape and V-convex shape, as claimed, as seen in Figs. 3 and 4. Also, the front unit 6 and back unit 7 are “mounted on frame on frame arrangement,” as claimed, because the front filter unit 6 is mounted within the back filter unit 7. See Lans Figs. 3, 4, [0051].
The air intake comprises a rack construction 14 configured to accommodate a predefined number of particle filter assemblies. See Lans Fig. 2, [0053]. The rack construction 14 reads on the “single filter rack configured to accommodate a predefined number of filter frame.”
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Lans differs from claim 1 because it teaches that the particle filter assembly (the “filter frame”) comprises two stage filter media (the front and back filter units 6, 7) instead of “at least three stage filter media,” as claimed. Lans also differs from claim 1 because it is silent as to the particle filter assembly including a carbon filter configured to eliminate formaldehyde, odors and volatile organic compounds in air and improve air quality suitable for breathing.
But Lans teaches that the particle filter assembly can be used to remove harmful and unwanted contaminants from ventilation air that is supplied to a building. See Lans [0002], [0016]–[0017]. Also, the front and back filter units 6, 7 each comprise a filter body in the form of a pocket. Id. at [0056].
With this in mind, Fukuda teaches an adsorptive filter material for removing harmful gases or odors from air. See Fukuda col. 1, ll. 9–29. The adsorptive filter material comprises active carbon fibers. See Fukuda col. 1, ll. 9–23. The adsorptive filter material is capable of being formed into pocket shape (similar to the front and back filter units 6, 7) because it can be made into a bag form. Id. at Fig. 4, col. 3, ll. 17–28. The adsorptive filter material is beneficial because it can eliminate various harmful gases or odors from air. Id. at col. 1, ll. 9–23.
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for the particle filter assembly of Lans to include a third filter unit (with a similar structure as the front and back filter units 6, 7, and which is mounted within one of the filter units 6, 7 in the same way that front filter unit 6 is mounted in back filter unit 7 as seen in Figs. 3 and 4) with a filter body made from the adsorptive filter material of Fukuda to enable the particle filter assembly to remove harmful gases or odors from the ventilation air that is supplied to the building.
With this modification, the third filter unit (with a similar structure as the front and back filter units 6, 7) with a filter body made from the adsorptive filter material of Fukuda reads on the “carbon filter” because the adsorptive filter material comprising active carbon fibers. See Fukuda col. 1, ll. 9–23. The adsorptive filter material is capable of eliminating odors. Id. The adsorptive filter material is also capable of eliminating formaldehyde and volatile organic compounds from air because it comprises active carbon, which is a material that can adsorb volatile organic compounds and formaldehyde. See e.g., Ohashi et al., US 2010/0010130 A1, [0002] (active carbon is a material capable of adsorbing volatile organic compounds such as formaldehyde).
Regarding claim 2, Lans teaches that the particle filter assembly (the “filter frame”) comprises a filtering material that can be made of polymer fibers. See Lans [0022]. The polymer of the polymer fibers reads on the claimed “plastic.”
Regarding claim 3, Lans teaches that the particle filter assembly (the “filter frame”) is an “air bypass leak proof frame, wherein the leakproof frame is configured to form an airtight seal with the single rack to prevent air bypass,” as claimed, because the particle filter assembly is configured to be mounted in the rack construction 14 so that an air stream will pass through the particle filter assembly without bypassing it. See Lans [0053], [0065].
Regarding claim 6, Lans teaches that the front filter unit 6 (the “pre-filter”) has an efficiency of 90% for 0.4 micron particles. See Lans [0058]. This converts to a MERV of 16. See “What is a MERV rating,” EPA, https://19january2021snapshot.epa.gov/indoor-air-quality-iaq/what-merv-rating-1_.html. A MERV rating of 16 reads on “at least one of a series of MERV-8 class air filters” because the phrase “at least one” is interpreted to mean that the pre-filter has a MERV rating of at least 8.
Regarding claim 7, the claim requires that, for the air filter assembly of claim 1, the “sigma convex shape is obtained by folding so as to create mountain folds and valley folds to lock the at least tree stage filter media with each other.” The sigma convex shape is optional because the air filter assembly of claim 1 comprises at least one of a sigma convex shape and a V-convex shape, while claim 7 fails to specify that the air filter assembly comprises the sigma convex shape. Therefore, under the broadest reasonable interpretation, the language of claim 7 fails to further limit the scope of the claimed air filter assembly.
Also, the limitations of claim 7 describe the process of manufacturing the air filter assembly because the limitations indicate that the sigma convex shape is “obtained by folding so as to create mountain folds and valley folds to lock the at least tree stage filter media with each other.” The patentability of a product does not depend on its method of production unless the process steps imply structure. See MPEP 2113, subsection I. Here, the sigma shape of the modified particle filter assembly of Lans is the same structure as claimed (i.e., three filter stages locked together with each other). Therefore, Lans as modified reads on the claim even if it is manfuactured using a different process.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Lans, US 2012/0272632 A1 in view of Fukuda et al., US 4,181,513 and in further view of Simmons et al., US 2017/0128868 A1.
Regarding claim 4, Lans teaches that the front filter unit 6 (the “pre-filter”) is connected to the rack construction 14 (part of the air channel) by locking elements so that it can be removed from the back filter unit 7 while the back filter unit 7 remains int eh air channel. See Lans [0009], [0029], [0053]. The locking elements read on the “plurality of mechanical clamps…configured to remove or fix the pre-filter individually without disturbing a filter from the at least three stage filter media.”
Lans differs from claim 4 because it is silent as to the locking elements having a “turn-key,” as claimed. But Lans teaches that the locking elements can be of any suitable kind, including screws, nuts, interlocking elements, snapping elements or the like. See Lans [0029].
With this in mind, Simmons teaches an air intake structure 4 with a filter screen 22 removably attached to it. See Simmons Fig. 1, [0084]–[0086]. The filter screen 22 is attached to the intake structure 4 using various mechanism including bolt fasteners 30 and wing nuts 40 (Fig. 1) or twist lock fasteners 86 (Fig. 7). Id. at Figs. 1, 7, [0087]–[0088], [0096]. The twist lock fasteners 86 are “mechanical clamps having a turn-key” because they fix the filter screen 22 to the air intake structure 4 using a mechanism where twist and lock portion 90 of each fastener 86 is inserted through an aperture 96 on the filter screen 22 with the twist and lock portion 90 then being turned to lock the filter screen 22 in place. Id. at Figs. 7, 8, [0096]–[0097].
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the fasteners 86 of Simmons as the locking elements of Lans because this would merely represent the simple substitution of one known element for another to yield predictable results. See MPEP 2143, subsection I, B. With this modification, the fasteners 86 read on the “mechanical clamps having a turn-key.”
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Lans, US 2012/0272632 A1 in view of Fukuda et al., US 4,181,513 and in further view of Langlands et al., US 2009/0031682 A1.
Regarding claim 5, Lans teaches that the back filter unit 7 (the “fine filter”) comprises a filter material mat (the “fine filter media”) that is attached to a frame 12 (the “filter frame”). See Lans Fig. 4, [0051].
Lans differs from claim 5 because it is silent as to the filter material mat being adhered to the frame 12 using a chemical adhesive.
But Langlands teaches a pocket filter assembly (similar to the back filter unit 7 of Lans) comprising a filter media 102 that is inserted into a channel 116 of a frame (header elements 104, 105) with the filter media 102 being attached to the frame by an adhesive comprising a thermosetting liquid resin (a chemical adhesive) that is poured into the channel 116. See Langlands Fig. 5A, [0021]. The attachment mechanism between the frame and the filter media 102 is beneficial because it provides a relatively strong attachment as the adhesive becomes unitary with the filter media 102 when it solidifies. Id.
It would have been obvious to one of ordinary skill in the art before the effective date of the claimed invention to use the attachment mechanism of Langlands to attach the filter material of the back filter unit 7 to the frame 12 to provide a relatively strong attachment between the filter material and the frame 12. With this modification, the thermosetting liquid resin reads on the “chemical adhesive.”
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Lans, US 2012/0272632 A1 in view of Fukuda et al., US 4,181,513 and in further view of Dralle, US 2013/0019578 A1.
Regarding claim 8, Lans as modified teaches the limitations of claim 1, as explained above.
Lans as modified differs from claim 1 because it is silent as to the combined air pressure drop of the three filter units.
But Dralle teaches that the pressure drop of a filter is result effective because it impacts electrical power required to run fans and motors to move air through the filter. See Dralle [0005]. Dralle also teaches that a conventional HEPA filter has an initial pressure drop of 300 Pa (1.2 inches of water, i.e., WG) (id. at [0006]), and teaches a pocket-style filter with four stages with a lower initial pressure drop than standard HEPA filters (id. at [0043]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use routine experimentation to determine the optimal combined initial air pressure drop of the particle filter assembly of modified Lans to optimize the amount of electricity required to move air through the filter assembly. A person of ordinary skill in the art would have had a reasonable expectation of success in achieving an initial pressure drop within eh claimed range of less than 1.5 WG, because Dralle teaches a pocket-style filter with four stages having an initial pressure drop less than 1.2 WG. See MPEP 2144.05, subsection II (where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation).
Response to Arguments
Claim Objections
The Examiner withdraws the previous claim objections to claims 1 and 7, in light of the amendments.
Note, however, that claims 9 and 10 are objected to for the reasons stated above.
35 U.S.C. 112(b) Rejections
The Examiner withdraws the previous 35 U.S.C. 112(b) rejections.
Note, however, that claim 3 is rejected as indefinite for the reasons stated above.
35 U.S.C. 103 Rejections
Claim 1
The Applicant argues that claim 1 requires a filter frame comprising a sigma convex shape where the media itself is folded to create the structure. See Applicant Rem. filed February 25, 2026 (“Applicant Rem.”) 7. The Applicant argues that the sigma shape of Lans differs from claim 1, asserting that it is merely a spatial void between two flexible pockets. Id.
The Examiner respectfully disagrees. Initially, claim 1 fails to specify that the claimed “filter frame” comprises a sigma convex shape where the media itself is folded to create the structure. Also, even if claim 1 required this feature, the sigma shape of Lans is created by folding the filter media of the front unit 6 and the back unit 7 to form the pocket of each unit 6, 7.
The Applicant also argues that the pockets of Lans rely on airflow to inflate and maintain their shape, and asserts that if a rigid sigma fold was applied to the media of Lans, it would destroy the aerodynamic pocket function of Lans. See Applicant Rem. 7.
The Examiner respectfully disagrees. Claim 1 does not mention the rigidity of the filter frame required to form the sigma convex shape or the V-convex shape. Also, Lans does not rely on airflow to maintain the shape, at least because the framework structure 16 maintains the shape of the front and back units 6, 7.
The Applicant further argues that it would not have been obvious to add a third filter unit with a body made of the adsorptive filter material of Fukuda. Instead, the Applicant argues that Lans is directed toward gas turbine plant air intakes, and asserts that the filter material of Fukuda is a dense, needle-punched felt of active carbon fibers. See Applicant Rem. 8. The Applicant argues that applying the material of Fukuda to the construction of Lans would increase the weight and thickness of the media stack, causing the pockets of Lans to sag and deflect under the relatively high-velocity intake of a turbine. Id. The Applicant also argues that the material of Fukuda is fundamentally incompatible with Lans due to the density of the material, with Lans requiring high-flow, asserting that introducing such a dense layer into the nested bag design of Lans would create a massive air resistance bottleneck. Id.
The Examiner respectfully disagrees. Initially, the air intake of Lans is not limited to gas turbines. Instead, the air intake can be used for various applications, including supplying ventilation air to a building. See Lans [0016]–[0017]. The filter material of Fukuda is useful for removing odors and harmful gases from air (see Fukuda col. 1, ll. 15–20), and a person of ordinary skill in the art would have understood the benefit of using the filter material of Fukuda with the air intake of Lans to remove odors and harmful gases from the ventilation air supplied to the building. Further, Lans is silent as to the density or permeability of the filter material used to make the filter units 6, 7, and Lans also teaches that the air intake is designed with a cross area that is large enough to allow for the desired air stream speed. See Lans [0067]. Therefore, even if there was a concern about the filter material of Fukuda being restrictive—the cross area of the filter unit could be increased to achieve the desired air flow speed.
Claim 8
The Applicant argues that the features of claim 8 of a combined air pressure drop of less than 1.5 inch WG and a 70% reduction against a panel filter is non-obvious for being unexpected. See Applicant Rem. 8–9.
The Examiner respectfully disagrees, at least because claim 8 does not require a 70% reduction against a panel filter.
Claim 4
The Applicant argues that claim 4 is non-obvious asserting that Simmons is non-analogous art. See Applicant Rem. 9–10. Specifically, the Applicant argues that Simmons is directed to an exterior air intake structure for a plant, and that a person of ordinary skill in the art seeking to solve the problem of internal HVAC filter by pass would not look to an outdoor screen for a solution. Id.
The Examiner respectfully disagrees. Simmons is analogous art because it is in the same field of endeavor as the claimed invention of air filtration. Also, Simmons is analogous art because it is reasonably pertinent to the problem faced by the inventor of attaching a filter to a housing.
Claim 5
The Applicant argues that it would not have been obvious for the filter media of the back filter unit 7 to be attached to the frame 12 using a chemical adhesive. See Applicant Rem. 10–11. Instead, it is argued that claim 5 requires that the chemical adhesive is configured to enable the media to withstand high air resistance. Id.
The Examiner respectfully disagrees at least because claim 5 does not require that the chemical adhesive is configured to withstand high air resistance. Note that even if the claim was amended to require this feature, it would raise issues of indefiniteness as noted in the Non-Final Rejection dated November 26, 2025.
The Applicant further argues that the geometry maximizes surface area, and that under high velocity airflow, the assembly would be prone to deflection or collapse if they were only mechanically held or lightly glued. See Applicant Rem. 11. The Applicant argues that the chemical adhesive acts as a structural binder that unifies the three media types, preventing delamination. Id.
The Examiner respectfully disagrees. Claim 5 is silent as to the chemical adhesive adhering the three layers together, as it merely says that the fine filter media is adhered to the filter frame using a chemical adhesive. Also, the claim fails to specify the strength of the chemical adhesive, and therefore a relatively light chemical adhesive would read on the claim.
The Applicant further argues that the adhesive is essential in achieving an air bypass leak proof assembly. See Applicant Rem. 11.
The Examiner respectfully disagrees at least because this feature is not included in claim 5. Even if it was, the back filter unit 7 to be attached to the frame 12 so that it will not leak (otherwise the filter would be ineffective for allowing contaminants to bypass the frame).
Claim 6
The Applicant argues that the front filter unit 6 of Lans does not have a MERV-8 rating—even though it has an efficiency that overlaps with this rating—asserting that Lans achieves high efficiency using massive, deep, flexible pockets designed for gas turbine intakes, while asserting that claim 6 requires efficiency to be part of at least three stage filter media with an integrated frame, while simultaneously reducing pressure drop by 70%. See Applicant Rem. 12.
The Examiner respectfully disagrees. Claim 6 is not specific about how the MERV-8 rating is achieved. The front filter unit 6 of Lans has a rating that overlaps with a MERV-8 rating for the reasons explained in the 35 U.S.C. 103 rejection above.
Claim 7
The Applicant argues that mountain folds and valley folds of claim 7 are not just a way to make the filter, but are the mechanism used to lock the three stage filter media with each other. See Applicant Rem. 12. The Applicant also argues that in Lans, the filter units 6, 7 are nested with each other, and asserts that this provides no structural rigidity. The Applicant argues that the mountain and valley folds eliminate the need for structural support by creating a self-supporting, rigid Sigma structure that overcomes expected deflection. Id.
The Examiner respectfully disagrees, at least because there is no language in claim 7 requiring that that the structure is self-supporting.
Claim 2
The Applicant argues that the polymer fibers of Lans cannot read on the “filter frame comprises a material comprising Plastic” as required by claim 2. See Applicant Rem. 13. Instead, it is argued that in the context of the claimed “frame on frame” design, the use of a rigid plastic frame is a deliberate structural choice, allowing for a lightweight, corrosion-resistant and leak-proof seal that is superior to the sliding rail systems of Lans. Id.
The Examiner respectfully disagrees. The claimed “filter frame” includes the “filter media” as recited in claim 1, which says “the filter frame (20) comprises at least three stage filter media.” Claim 2 requires that some portion of the “filter frame” comprises a material from a list including plastic. Claim 2 is not specific about which part of the “filter frame” comprises plastic and is not specific about the plastic being rigid. In Lans, the filter material of the front and back units 6, 7 is part of the structure that reads on the claimed “filter frame.” The filter material can be made of polymer fibers, and therefore the “filter frame comprises a material comprising Plastic” as claimed.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to T. BENNETT MCKENZIE whose telephone number is (571)270-5327. The examiner can normally be reached Mon-Thurs 7:30AM-6:00PM.
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T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776