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 § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 5, 6, 9 and 10 are rejected under 35 U.S.C. §103 as being unpatentable over Shimmura et al. (US 2006/0124289 A1) in view of Kaga (JP 4055449 B2), further in view of Huazhao et al. (US 2010/0243226 A1) and further in view of Zhang (US 6,907,919 B2).
In regard to claim 5, Shimmura teaches a multi-channel heat exchanger comprising:
a plurality of heat exchange tubes spaced apart along a thickness direction of the plurality of heat exchange tubes (see FIGS. 1-3; ¶¶ 0040-0044, describing flat heat exchanging tubes 30 arranged in parallel at intervals between header tanks 10a, 10b),
each of the plurality of heat exchange tubes (30) has a first longitudinal side face and a second longitudinal side face opposite to and parallel to each other along the thickness direction, and a third longitudinal side face and a fourth longitudinal side face opposite to each other along a width direction, and a distance between the first longitudinal side face and the second longitudinal side face is less than a distance between the third longitudinal side face and the fourth longitudinal side face (see, FIG. 5B; ¶¶ 0044, 0048, showing tubes 30 having a flat cross section with width larger than thickness and refrigerant passages 35 arranged in the tube-width direction),
each heat exchange tube of the plurality of heat exchange tubes (30) is divided into four portions along the width direction of the plurality of heat exchange tubes, the four portions comprising first through fourth heat exchange tube portions distributed from an inlet side of airflow to an outlet side of airflow (see, FIGS. 3-5 and Claim 12; ¶¶ 0048-0052, describing four passage groups/passes P1-P4 arranged in parallel in the tube-width direction with cooling air introduced from the front side and passing from the fourth pass P4 toward the first pass P1),
each heat exchange tube portion of the four heat exchange tube portions includes at least a portion of at least two flow channels, each flow channel of the at least two flow channels extending in a length direction of the plurality of heat exchange tubes, and respective flow channels of the at least two flow channels of the four heat exchange tube portions are spaced along the width direction (see FIG. 5B and Claim 1; ¶¶ 0044, 0048, describing a plurality of refrigerant passages 35 extending in the tube longitudinal direction and arranged in parallel in the width direction within each of passes P1-P4),
each heat exchange tube has a cross section comprising a flow section, the flow section having a total flow-section area, the total flow-section area comprising a first flow-section area A1, a second flow-section area A2, a third flow-section area A3 and a fourth flow-section area A4 of the first to fourth heat exchange tube portions (see FIG. 5B and Claim 12; ¶ 0048, describing rectangular refrigerant passages 35 grouped into four passage groups/passes P1-P4 each defining a respective total flow-section area in the tube-width direction),
a fin (40) is arranged between two heat exchange tubes of the plurality of heat exchange tubes (30) along the thickness direction and connected to the two heat exchange tubes (see FIGS. 1-3; ¶ 0042, describing corrugated fins 40 disposed between adjacent heat exchanging tubes 30 and brazed thereto).
However, Shimmura does not explicitly teach that the four heat exchange tube portions are equal in width along the width direction, nor that A1 = 1.05-1.4 times A4.
Kaga teaches a flat heat-transfer tube in which a partition wall 14a separates the internal flow paths into a windward-side path 6a and a leeward-side path 6b, and in which the leeward-side path 6b has a smaller cross-sectional flow area while the windward-side path 6a has a larger cross-sectional flow area so that more refrigerant circulates in the windward-side path to improve heat exchange (see Kaga, ¶¶ 0030-0031; FIG. 15, see the attached English translation of Kaga in the previous office action), the four portions are equal in width along the width direction (Kaga, FIG. 15; ¶ 0030, showing flow-path portions partitioned across the tube width as discrete portions of comparable width along the width direction), and A1 = 1.05-1.4 times A4 (Kaga, ¶¶ 0030-0031; FIG. 15, teaching that the windward-side flow-section area is greater than the leeward-side flow-section area as a result-effective variable governing how much refrigerant circulates through each tube portion).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the four passage groups of Shimmura to be of equal width along the tube-width direction and to set A1 to 1.05-1.4 times A4 in view of Kaga, in order to circulate more refrigerant on the windward side than on the leeward side and thereby improve heat exchange (Kaga). The recited 1.05-1.4 ratio is a routine optimization of a result-effective variable, namely the relative windward-side and leeward-side refrigerant flow area, the heat-exchange benefit of which is expressly identified by Kaga.
Shimmura in view of Kaga does not explicitly teach that the fin comprises first to nth groups of fins distributed from the inlet side of airflow to the outlet side, that an air-side heat-transfer coefficient of the nth group is less than that of the first group, or the louver opening-angle relationship R(k-1) > Rk.
Huazhao teaches a fin for a heat exchanger having louvers through which air successively flows, the louvers being divided in the airflow direction into a leading/upstream set and a trailing/downstream set and being further divisible into sub-sets along the airflow direction, with the louver tilt angle decreasing continuously in the airflow direction such that α1 > α2 > α3 > α4 > α5 > α6 > α7 > α8, and with the leading-set first tilt angle larger than the trailing-set second tilt angle (see Huazhao, Claims 5, 6, 8, and 9; ¶¶ 0016, 0028, 0043; FIGS. 3-5), the fin comprises first to nth groups of fins distributed along the direction from the inlet side of airflow to the outlet side of airflow, where 1 < n and n is an integer (Huazhao, Claims 6 and 9; ¶¶ 0016, 0043; FIGS. 3 and 5, dividing the louvers into leading/upstream and trailing/downstream sets along airflow and further into sub-sets along the airflow direction), an air-side heat-transfer coefficient of the nth group of fins is less than an air-side heat-transfer coefficient of the first group of fins (Huazhao, ¶¶ 0028, 0043; FIG. 5, teaching the leading-set tilt angle larger than the trailing-set tilt angle to provide stronger heat-exchange performance on the upstream side; further supported by Zhang, FIGS. 1, 2, and 5, teaching front/leading louvers thin the thermal boundary layer and enhance heat-transfer performance on the inlet side), and an opening angle of the louver of the first group of fins is R1, an opening angle of the louver of the kth group of fins is Rk, an opening angle of the louver of the nth group of fins is Rn, and R(k-1) > Rk (Huazhao, Claims 5 and 8; FIGS. 4-5; ¶¶ 0028, 0043, teaching α1 > α2 > α3 > α4 > α5 > α6 > α7 > α8 along the airflow direction).
In addition, Zhang teaches that front/leading vortex-generator louvers thin the thermal boundary layer and enhance heat-transfer performance on the inlet side of the fin (see Zhang, FIGS. 1, 2, and 5; col. 4, ll. 30-55).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the corrugated fins of Shimmura/Kaga to comprise first to nth louvered fin groups distributed from the inlet side of airflow to the outlet side, with the louver opening angle decreasing along the airflow direction and the air-side heat-transfer coefficient of the nth group less than that of the first group, in view of Huazhao and Zhang, in order to match louver tilt angle to the airflow-direction frost distribution, preserve airflow space downstream, limit pressure drop, and concentrate heat-transfer enhancement on the inlet side where the air-to-refrigerant temperature differential is largest.
PNG
media_image1.png
367
786
media_image1.png
Greyscale
In regard to claim 6, the modified Shimmura teaches the heat exchanger of claim 5, including a fin comprising first to nth louvered fin groups distributed along the airflow direction with the air-side heat-transfer coefficient of the nth group less than that of the first group and with louver opening angle decreasing along the airflow direction (see Huazhao, ¶¶ 0028, 0043; FIGS. 3-5; Zhang, FIGS. 1, 2, and 5).
the number of the louvers of the first group of fins is greater than the number of the louvers of the nth group of fins (see Huazhao, ¶¶ 0028, 0043; FIGS. 3-5, teaching that louver number, density, and pitch along the airflow direction are design parameters adjusted along airflow to balance airflow space, frost accommodation, and heat-exchange performance; Zhang, FIGS. 1, 2, and 5, teaching that front/leading louvers thin the thermal boundary layer and enhance air-side heat-transfer performance on the inlet side).
The number, density, and pitch of louvers along the airflow direction are recognized result-effective variables, because they directly govern the air-side heat-transfer coefficient, the airflow pressure drop, and the available airflow space for frost accommodation (see Huazhao, ¶¶ 0028, 0043).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to provide a greater number of louvers in the first/inlet-side fin group than in the nth/outlet-side fin group, in view of Huazhao and Zhang, as a routine optimization of louver density along the airflow direction, in order to (a) maintain the recited heat-transfer-coefficient relationship in which the first/inlet-side group is greater than the nth/outlet-side group, consistent with the leading-edge enhancement taught by Zhang, and (b) preserve adequate downstream airflow space and limit downstream pressure drop and frost-bridging, consistent with the upstream-larger-gap and upstream-larger-tilt teachings of Huazhao. It has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges of a result-effective variable involves only routine skill in the art. See In re Aller, 220 F.2d 454, 456 (CCPA 1955).
In regard to claim 9, the modified Shimmura further teaches: a flow sectional area of each flow channel in the same heat exchange tube portion is the same (Shimmura, FIG. 5B and Claim 12; ¶¶ 0044, 0048, showing rectangular refrigerant passages 35 of the same cross section arranged in parallel within each of passes P1-P4).
In regard to claim 10, the modified Shimmura teaches the multi-channel heat exchanger according to claim 9, wherein Shimmura further teaches: a shape of a cross section of each flow channel in the same heat exchange tube portion is the same (Shimmura, FIG. 5B and Claim 1; ¶¶ 0044, 0048, 0111-0112, showing rectangular refrigerant passages 35 of the same cross-sectional shape within each pass) and each heat exchange tube portion comprises a same number of flow channels (Shimmura, FIG. 5B and Claim 12; ¶ 0048, showing refrigerant passages 35 grouped into four passage groups/passes P1-P4 in the tube-width direction with passages of like geometry distributed across the passes).
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Shimmura in view of Kaga, Huazhao and Zhang as applied to claim 5 above, and further in view of Yanik et al. (US 2012/0267086 A1).
In regard to claim 2, the modified Shimmura teaches the heat exchanger of claim 5 but does not explicitly teach that distances from at least one of the at least two flow channels in the four heat exchange tube portions to two flow channels adjacent thereto are different.
Yanik teaches a flat heat exchange tube having rectangular flow paths (198) of constant size with the spacing between adjacent flow paths increasing toward the trailing edge, including a leading-edge spacing U, a center spacing V approximately twice U, and successively larger spacings W and X across the tube width (see Yanik, FIG. 14; ¶¶ 0072-0075, 0076, 0078), and distances from at least one of the at least two flow channels in the four heat exchange tube portions to two flow channels adjacent to the at least one of the at least two flow channels are different (see Yanik, FIG. 14; ¶¶ 0072-0075, 0076, 0078, showing flow-path-to-flow-path spacings U, V, W, X that are unequal across the tube width such that at least one flow channel has different distances to its two adjacent flow channels).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the spacing of the refrigerant passages 35 of Shimmura across the tube width to be unequal in view of Yanik, in order to concentrate refrigerant flow near the leading edge of the tube where the temperature differential with the external airflow is largest while keeping flow paths of constant size.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Shimmura in view of Kaga, Huazhao and Zhang as applied to claim 5 above, and further in view of Yonezawa (JP 2005-201491 A).
In regard to claim 3, the modified Shimmura teaches the heat exchanger of claim 5, but does not explicitly teach that a distance between any two adjacent flow channels in the first heat exchange tube portion is greater than or equal to a distance between any two adjacent flow channels in the second heat exchange tube portion.
Yonezawa teaches a flat tube (1) having a windward side A1 with three larger square refrigerant passage holes 9a and a leeward side B1 with six smaller refrigerant passage holes 9b, such that the windward-side adjacent-channel spacing is greater than the leeward-side adjacent-channel spacing (see Yonezawa, FIG. 2; ¶¶ 0017-0020), and a distance between any two adjacent flow channels in the first heat exchange tube portion is greater than or equal to a distance between any two adjacent flow channels in the second heat exchange tube portion(Yonezawa, FIG. 2; ¶¶ 0017-0020, showing windward-side passage holes 9a spaced apart by a larger distance than leeward-side passage holes 9b).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to set the adjacent-channel spacing in the first (windward) tube portion of Shimmura to be greater than or equal to that in the second tube portion in view of Yonezawa, in order to balance windward-side and leeward-side heat exchange and provide a uniform temperature gradient across the tube.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Shimmura in view of Kaga, Huazhao and Zhang as applied to 6 above, and further in view of Antonijevic (US 2005/0077036 A1).
In regard to claim 7, the modified Shimmura teaches the multi-channel heat exchanger according to claim 6, wherein the claim requires at least one of (a) the opening width of the louver of the first group is greater than the opening width of the louver of the nth group, or (b) the opening length of the louver of the first group is greater than the opening length of the louver of the nth group, wherein Huazhao further teaches that a louver gap located upstream in the airflow direction is greater than or equal to an adjacent downstream louver gap, with at least one upstream gap larger than its adjacent downstream gap, and with a leading-set first louver gap D1 greater than a trailing-set second louver gap D2 (see Huazhao Claims 2, 3, and 6; FIGS. 2, 3, and 5; ¶ 0028), and an opening width of the louver of the first group of fins is greater than an opening width of the louver of the nth group of fins (see Huazhao, Claims 2, 3, and 6; FIGS. 2, 3, and 5; ¶ 0028, teaching the upstream louver gap larger than the adjacent downstream louver gap and the leading-set first louver gap D1 greater than the trailing-set second louver gap D2).
Antonijevic teaches that louver geometry parameters include louver length L, louver width B, and inclination angle α, and that a louver array may include at least one louver having an unequal length L′ relative to an adjacent louver and at least one intermediate louver having an unequal width B′ relative to an adjacent intermediate louver, including longer passage slots S′ (see Antonijevic, ¶¶ 0020, 0027, 0029, 0037-0038, 0095-0097; Claims 17, 20, 25, and 29), and an opening length of the louver of the first group of fins is greater than an opening length of the louver of the nth group of fins (see Antonijevic, ¶¶ 0020, 0027, 0029, 0037-0038, 0095-0097; Claims 17, 20, 25, and 29, teaching unequal louver length L′ across the louver array and identifying louver length L as a design parameter of the louver geometry).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to provide the first/inlet-side louver group with a greater opening width than the nth/outlet-side louver group in view of Huazhao, in order to accommodate greater upstream frost formation and preserve airflow through the fin while limiting downstream pressure drop, as expressly taught by Huazhao (¶ 0028; FIG. 5). Alternatively, it would have been obvious to provide the first/inlet-side louver group with a greater opening length than the nth/outlet-side louver group in view of Antonijevic, as a routine optimization of louver length to balance heat-transfer performance and pressure drop along the airflow direction, Antonijevic expressly identifying louver length L as a louver geometry parameter that may be unequal across the louver array.
Response to Arguments
Applicant’s arguments with respect to the amended claims have been considered but are moot in view of the new ground(s) of rejection.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to WEBESHET MENGESHA whose telephone number is (571)270-1793. The examiner can normally be reached Mon-Thurs 7-4, alternate Fridays, EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Frantz Jules can be reached at 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
Prosecution Insights