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 Rejections - 35 USC § 102(a)(1)
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
The claims are rejected as follow:
Claims 1, 5–8, 11–16, 23 and 25 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Borla et al., US 2003/0089233 A1 (“Borla”).
Regarding claim 1:
Borla discloses that a filter unit (Borla’s air filtration device 8, Borla Fig. 1, [0018]) for a continuous flow engine (Borla discloses its filtration device is for gas turbine engine, Borla Fig. 1, [0002], which is continuous flow engine,),
wherein the filter unit (8 of Borla) is adapted to filter a fluid stream (Borla discloses as air stream, Borla [0010]),
wherein the filter unit comprises: a strainer part (Borla’s air filter element 10, Borla Fig. 1, [0019]) providing two strainer surfaces (interior and exterior of Borla’s air filter element 10, Id.),
wherein at least one of the two strainer surfaces is not planar (both of Borla’s interior and exterior surface of its filter element 10 is not planar, Id.),
wherein the filter unit (8 of Borla) is adapted to filter a fluid stream providing a flow direction (direction is shown in Borla’s Fig. 3, Borla Fig. 3),
wherein the strainer part provides an upstream surface (external face of Borla’s filter 10 as shown in Fig. 3) and a downstream surface based on the flow direction (interior face of Borla’s filter 10 as shown in Fig. 3),
wherein the strainer part (10 of Borla) contains at least one reinforcement structure (Borla’s root apex 34 or peak apex 36, Borla Fig. 1, [0019]),
wherein the at least one reinforcement structure (34 or 36 of Borla) contains at least one reinforcement rib (Borla’s root apex 34 is shown as a rib, Borla Fig. 2, [0019]),
and wherein the filter unit (8 of Borla) provides an inner cavity (interior of Borla’s housing 12, Borla Fig. 3, [0023]) containing the strainer part (10 of Borla, Borla Fig. 3) and being adapted to allow a flow of the fluid stream through the filter unit (as indicated by flow arrow, Borla Fig. 3),
and wherein the inner cavity (interior of Borla’s housing 12) provides an inhomogeneous thickness where directly abreast the strainer part (as shown in Fig. 3 of Borla),
wherein the inhomogeneous thickness comprises an upstream diameter at an upstream end of the strainer part (see annotated Fig. 3 of Borla),
a downstream diameter at a downstream end of the strainer part (see annotated Fig. 3 of Borla),
and a middle diameter in between the upstream end and the downstream end (see annotated Fig. 3 of Borla),
wherein the middle diameter is larger than the upstream diameter and the downstream diameter (see annotated Fig. 3 of Borla),
and wherein transitions between the upstream diameter and the middle diameter and between the middle diameter and the downstream diameter each comprise a respective curve (see annotated Fig. 3 of Borla).
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Regarding claim 5:
Borla discloses that the filter unit according to claim 1,
wherein the upstream surface provides a displacement distance of at least 10% of an average inner diameter of the filter unit in a cross section perpendicular to the flow direction, wherein the displacement distance is a length of a projection of the upstream surface in cross sections along the flow direction onto an axis through the middle of the filter unit in the flow direction (as shown in Borla’s Fig. 3, Borla’s external surface provides a displacement distance that is at least 10% of average inner diameter of the inner filter unit in a cross section perpendicular to the flow direction, Borla Fig. 3).
Regarding claim 6:
Borla discloses that the filter unit according to claim 1,
wherein the upstream surface provides a maximum displacement distance being a highest displacement distance available (the maximum displacement distance would be from Borla’s apex edge 24 to mounting flange 32, Borla Fig. 2),
wherein the displacement distance is a length of a projection of the upstream surface in cross sections along the flow direction onto an axis through the middle of the filter unit in the flow direction (Borla’s maximum displacement as mapped above meets this limitation), and
wherein at least 20% of the upstream surface provides a displacement distance of at least 50% of the maximum displacement distance in relation to a most upstream located point of the upstream surface (as shown in Borla’s Fig. 3, in relation to a most upstream located pointed of the upstream surface—Borla’s leading apex edge 24, the entire upstream surface provides the maximum displacement distance, and therefore meets the limitation, Borla Fig. 3).
Regarding claim 7:
Borla discloses that the filter unit according to claim 1, wherein the upstream surface provides a maximum displacement distance being a highest displacement distance available (the maximum displacement distance would be from Borla’s apex edge 24 to mounting flange 32, Borla Fig. 2),
wherein the displacement distance is a length of a projection of the upstream surface in cross sections along the flow direction onto an axis through the middle of the filter unit in the flow direction (mapping of Borla’s maximum displacement distance is made according to this limitation),
and wherein at least 15% of the upstream surface provides a displacement distance of at most 40% of the maximum displacement distance in relation to a most upstream located point of the upstream surface (as shown in Borla’s Fig. 3, 15% of upstream surface provides a displacement distance of less than 40% of the maximum displacement distance in relation to Borla’s leading apex edge 24 and therefore meets the limitation, Borla Fig. 3, [0019]).
Regarding claim 8:
Borla discloses that the filter unit according to claim 1,
wherein the upstream surface provides a shape of a furbelow (Borla’s root apex 34 and peak apex 36 forms a shape of furbelow, Borla Fig. 3, [0019]).
Regarding claim 11:
Borla discloses that the filter unit according to claim 1,
wherein the strainer part provides a shape of a deformed plane (Borla’s fitler element has a general cone shape configuration, which reads on a shape of a deformed plane, Borla Fig. 3, [0019]),
wherein the deformed plane is characterized by indentations in a downstream direction (Borla’s peak apex 36 as shown in Fig. 2 reads on indentations in a downstream direction, Borla Fig. 2, [0019]), and
wherein the indentations are located around a central point (Borla’s leading apex edge 24, Borla Fig. 3, [0019]) of the deformed plane being located in the middle of the deformed plane and located at an upstream end of the deformed plane (Borla’s leading apex edge 24 is located in the middle of the deformed plane and located at an upstream end of the deformed plane, Borla Fig. 3, [0019]).
Regarding claim 12:
Borla discloses that a kit (the system as shown in Fig. 3), comprising:
the filter unit according to claim 1 (see mapping in claim 1),
a counterpart (Borla’s mounting collar 18, Borla Fig. 3, [0024]) adapted receive the filter unit (10 of Borla),
wherein the counterpart (18 of Borla) is adapted to be used as part of the continuous flow engine (Borla discloses its mounting collar 18 abuts the inlet of engine intake manifold, Borla Fig. 3, [0024] and Borla discloses its engine could be a turbine engine, which is continuous flow engine, Borla [0002]).
Regarding claim 13:
Borla discloses that a continuous flow engine (Borla discloses its device could be used in large turbine engines, Borla [0002], which are continuous flow engines), comprising:
the filter unit according to claim 1 (as mapped in claim 1).
Regarding claim 14:
Borla discloses that a method of upgrading or servicing a continuous flow engine, wherein the method comprises:
introducing the filter unit according to claim 1 to filter the fluid stream of the continuous flow engine (process of using Borla’s filter as mapped in claim 1 in gas turbine engine applications, Borla Fig. 3, [0002]).
Regarding claim 15:
Borla discloses that a method for filtering a fluid stream of a continuous flow engine, comprising:
filtering the fluid stream with the filter unit according to claim 1 (process of using Borla’s filter as mapped in claim 1 in gas turbine engine applications, Borla Fig. 3, [0002]).
Regarding claim 16:
Borla discloses that the filter unit according to claim 1,
wherein the fluid stream comprises a gas stream (Borla uses term “air flow”, Borla Fig. 3, [0003]).
Regarding claim 23:
Borla discloses that the filter unit according to claim 1,
wherein the inhomogeneous thickness forms a continuous curve that extends along an entire axial length of the strainer part from the upstream end of the strainer part to the downstream end of the strainer part (as shown in annotated Fig. 3 of Borla presented in claim 1).
Regarding claim 25:
Borla discloses a filter unit for a continuous flow engine (Borla’s air filtration device 8, Borla Fig. 1, [0019]), wherein the filter unit is adapted to filter a fluid stream (Borla discloses as air flow, Borla Fig. 3), wherein the filter unit comprises:
a strainer part (Borla’s filter element 10, Borla Fig. 2, [0019]) providing two strainer surfaces (external and internal surface of Borla’s filter element 10, Borla Fig. 3);
wherein at least one of the two strainer surfaces is not planar (both are not planar as shown in Fig. 2 of Borla);
wherein the filter unit is adapted to filter a fluid stream providing a flow direction (flow direction is shown in Fig. 3 of Borla);
wherein the strainer part (10 of Borla) provides an upstream surface (external surface of Borla’s filter 10) and a downstream surface (internal surface of Borla’s filter 10) based on the flow direction (as shown in Borla Fig. 3);
wherein the strainer part (10 of Borla) contains at least one reinforcement structure (Borla’s root apex 34, Borla Fig. 2, [0019]);
wherein the at least one reinforcement structure (34 of Borla) contains at least one reinforcement rib (Borla’s root apex is shown as a ridge, Borla Fig. 2, [0019]);
wherein the filter unit provides an inner cavity (interior space of Borla’s filter housing 12, Fig. 3, [0022]) containing the strainer part (10 of Borla) and being adapted to allow a flow of the fluid stream through the filter unit (as shown in Fig. 3 of Borla);
wherein a gap is formed between a downstream end of the filter unit and the inner cavity (as clearly shown in Borla’s Fig. 3); and
wherein the gap is effective to permit fluid of the fluid stream to pass between the downstream end of the filter unit and the inner cavity (when air flow enters Borla’s tubular inlet 40, it will fill the inner cavity of housing 12, including the gap between a downstream end of the filter unit 10 and inner cavity of housing 12, and then enter interior of filter element 12 with perforations, and therefore read on limitation of effective to permit fluid to pass, Borla Fig. 3, [0019] and [0024]).
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.
The claims are rejected as follows:
Claim 4 is rejected under 35 U.S.C. 103 as being obvious over Borla in view of Ryon et al., US 2017/0204746 A1 (“Ryon”) and in further view of Crary, US 2003/0131828 A1 (“Crary”).
Regarding claim 4:
Borla discloses that the filter unit according to claim 1,
wherein the upstream surface provides openings (Borla discloses its pointed nose section 22 is perforated, Borla Fig. 2, [0019]).
Borla does not disclose that wherein at least 99% of the openings on the upstream surface of the strainer part provide a size of at most 80 µm in at least two dimensions being perpendicular to each other.
In the analogous art of stainers for continuous flow engine, Ryon discloses that is openings 132 could have at least two dimensions perpendicular to each other because Ryon’s opening 132 is rectangular shaped. Ryon Fig. 2B, [0028]. Ryon discloses that such shape enables strainer to impound particulate entrained in fluid traversing strainer body 100 of size that is smaller than that of the non-circular flow area, Ryon [0028]. It would therefore have been obvious for one ordinary skill in the art at the time of filing for Borla’s perforations to be rectangular shaped as disclosed by Ryon for the benefits disclosed above.
Additionally, similar to modified Borla, Crary discloses a strainer structure 106 for fuel injected engines. Crary Fig. 2, [0048]. Crary discloses its strainer body 106 comprises a mesh structure, where each mesh layer has an opening of 40-60 microns in size. Crary Fig. 5, [0062]. Crary discloses its strainer construction is commonly employed. Crary [0062]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Borla’s strainer to have a dimension similar to that disclosed by Crary because Crary discloses such dimension is “commonly” employed.
Claim 9 is rejected under 35 U.S.C. 103 as being obvious over Borla in view of Burns, WO 2014/174323 A1 (“Burns”)1.
Regarding claim 9:
Borla discloses that the filter unit according to claim 1,
wherein the strainer part provides at least one cavity to enable the fluid stream to flow through the strainer part from an upstream side to a downstream side (interior of Borla’s filter element 10 reads on the claimed “cavity”, Borla Fig. 3 [0019]),
wherein the at least one cavity provides openings on the upstream side and the downstream side of the strainer part (Borla discloses its filter element 10 is perforated, Borla Fig. 3, [0019]).
Borla does not disclose that wherein at least 90% of the openings on the downstream side are bigger than connected openings of the upstream side.
Similar to Borla, Burns discloses a strainer 310, Burns p. 13, ll. 28–30. Burns discloses its strainer comprises an upstream side 326 and a downstream side 324, where Burns’s upstream side 326 has a smaller opening size compared to its downstream side opening, Burns Fig. 6, p. 13, ll. 21–26. Burns discloses its embodiment of Fig. 6 reduces the damage of the distortion of the strand and reduces the likelihood of a pore becoming larger or smaller than intended, Burns Fig. 6, ll. 21–26. It would have been obvious for Ryon’s strainer to look like Burns for the benefits disclosed. With such modification, at least 90% of the opening would have bigger downstream side compared to its upstream side as shown by Burns.
Claim 17 is rejected under 35 U.S.C. 103 as being obvious over Borla.
Regarding claim 17:
Borla does not disclose that the filter unit according to claim 1,
wherein the at least one reinforcement structure (root apex 34 of Borla, Borla Fig. 2, [0019]) contains at least one reinforcement rib providing a thickness of at least 0.1 mm.
However, it would therefore have been obvious for one ordinary skill in the art at the time of filing for Borla’s reinforcement rib 34 to have a thickness of at least 0.1 mm to provide enough support strength to the strainer. Additionally, the instant disclosure does not teach the claimed thickness range is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Claims 19 and 22 are rejected under 35 U.S.C. 103 as being obvious over Borla in view of Breindl et al., US 2021/0156282 A1 (“Breindl”).
Regarding claim 19:
Borla does not disclose a method, comprising:
additively manufacturing the filter unit of claim 1 via the binder jetting.
Similar to Borla, Breindl discloses a strainer for tubine. Breindl [0001]. Breindl discloses its stainers is made of additive manufacturing including binder jetting. Breindl [0017]. Breindl discloses its production method of additive production offer a very high degree of design freedom in terms of the form of the passage opening, Breindl [0017]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use binder jetting to manufacture Borla’s strainer for the benefits of high degree of design freedom in terms of forming passage opening as disclosed by Breindl.
Regarding claim 22:
Borla does not disclose that the filter unit according to claim 1,
wherein the filter unit is manufactured using binder jetting.
Similar to Borla, Breindl discloses a strainer for tubine. Breindl [0001]. Breindl discloses its stainers is made of additive manufacturing including binder jetting. Breindl [0017]. Breindl discloses its production method of additive production offer a very high degree of design freedom in terms of the form of the passage opening, Breindl [0017]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use binder jetting to manufacture Borla’s strainer for the benefits of high degree of design freedom in terms of forming passage opening as disclosed by Breindl.
Allowable Subject Matter
Claim 24 would be allowable as stated in the previous office action dated Oct. 23, 2025.
Claim 24 would also be allowable in view of the newly cited prior art Borla. Because Borla does not disclose a plurality of ridges, each extending radially from the central point and all disposed within a common plane. It would not have been obvious for one ordinary skill in the art at the time of filing to modify Borla for such limitation because none of the prior art shows or renders such limitation as obvious.
Response to Arguments
Amended Claim 1 and dependent claims
In view of the newly proposed amendment, the examiner presents a new reference Borla. Details are provided above.
New Claim 25
Claim 25 is rejected in view of Borla, see details above.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to QIANPING HE whose telephone number is (571)272-8385. The examiner can normally be reached on 7:30-5:00 M-F.
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/Qianping He/Examiner, Art Unit 1776
1 Burns is the 22-page FOR dated Oct. 28, 2022.