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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on September 26th, 2025 has been entered.
Response to Arguments
Applicant's arguments filed September 26th, 2025 have been fully considered but they are not persuasive.
The Applicant argues that the references do not disclose a doubly-curved configuration in which the blade curves along two mutually intersecting directions (Remarks, pages 6-10) and Weetman fails to remedy the deficiency (Remarks, page 11). The Examiner respectfully disagrees because Weetman appears to disclose a doubly-curved configuration in which the blade curves along two mutually intersecting directions in that the tip 24 and an edge (either edge 26 or edge 28) are curved and intersect to meet the limitation (as shown below in the new grounds of rejection for claim 1). Thus, the argument is not persuasive.
The Applicant argues that the person of ordinary skill in the art would not have been motivated to change the varying thickness blade of Weetman II to one with uniform thickness (Remarks, page 15). The Examiner respectfully disagrees because Weetman teaches blades similar to Weetman II and Weetman teaches that the blades may have varying thickness or equal thickness through their length (col. 6, lines 34-35) where the “length” meets the limitation of “over an entire extension”. Thus, the argument is not persuasive.
The Applicant further argues that while Hjorth et al. may disclose uniform thickness the person of ordinary skill in the art would not be motivated to isolate and combine distinct features of applied prior art references explicitly having blades of varying thickness with blades having uniform thickness and there is no teaching or suggestion in any of the applied art references that any alleged benefits or improvements resulting from distinct features applied to a blade explicitly having variable thickness would also be possible in an application of those distinct features to an entirely different style of blade having uniform thickness (Remarks, page 15). The Examiner respectfully disagrees because Hjorth et al. appears to suggest that using the uniform thickness is an alternative to blade shapes having variable thickness (having rounded or streamlined shapes, page 1, lines 16-22) and provides motivation for using a uniform thickness (page 1, lines 54-57) as Hjorth et al. teaches the process of manufacturing a uniform blade is more cost efficient than methods such as casting (page 1, lines 22-30) and a blade of uniform thickness can still be shaped by rolling (page 1, lines 80-82) to achieve features such as angle, camber, and ratios. Thus, the argument is not persuasive.
It is noted that amending claim 1 as “a doubly-curved configuration in which the blade curves along two mutually intersecting directions such that the thrust side surface and the suction side surface each have concave curves;” or similar would likely render claim 1 allowable.
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 15, 18 and 30 are rejected under 35 U.S.C. 103 as being unpatentable over Weetman et al. (US 5344235) hereinafter “Weetman II” in view of Weetman (US 5112192) hereinafter “Weetman”, Engelbrecht et al. (US 4231974), Hjorth et al. (GB 1454277), Weetman (US 5951162) hereinafter “Weetman IV”, and Page (attached WO 2008025975A1).
Regarding claim 15, Weetman II discloses a propeller (Fig. 4 and Fig. 5) as shown below, the propeller comprising a hub (hub 28) and at least two blades (three blades: blades 22, Fig. 4) and “it is well-settled that the material worked upon by an apparatus does not limit apparatus claims. See MPEP 2115. Nonetheless, the propeller disclosed by Weetman II would be fully capable of use as a digestion tank mixer as Weetman II discloses the propeller is for use in mixing liquids and liquid suspensions (abstract).
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Weetman II discloses each blade comprises: A thrust side surface (pressure surface 12) and a suction side surface (surface 14, col. 3, lines 2-3); an inner edge fixedly connected to the hub (Fig. 4 and Fig. 5, blade portion along bases 26 and along hub 28) and an outer edge located at a distance from the hub (surface comprising tip 30); a leading edge (leading edge 10) extending from the inner edge to the outer edge and a trailing edge (trailing edge 16) extending from the inner edge to the outer edge (Fig. 4); an imaginary outer geometrical plane parallel to a center axis of the propeller (annotated above), perpendicular to a radius of the propeller (radius annotated above), and intersecting both the leading edge and the trailing edge (annotated above), the imaginary outer geometric plane comprising at least one of: (a) a leading intersection between the outer edge and the leading edge, and (b) a trailing intersection between the outer edge and the trailing edge (comprises both intersections as annotated above); an imaginary inner geometrical plane parallel to the imaginary outer geometrical plane and tangent to the hub (annotated above); a radial distance between and perpendicular to the imaginary outer geometrical plane and the imaginary inner geometrical plane (annotated above).
Weetman II discloses wherein at each imaginary intermediate geometrical plane located between and parallel to the imaginary outer geometrical plane and the imaginary inner geometrical plane along an entirety of the radial distance, each blade comprises: An arc-shaped cross section extending between the leading edge and the trailing edge (Fig. 2) and that is concave on the thrust side (high pressure surface 12 is concave as best shown in Fig. 2 and surface 42 is also thrust side and slightly concave as shown in Fig. 6, the thrust side surface is curved, col. 4, lines 52-57, and concave as shown in figures); a chord (chord 52) having a length that extends between the leading edge and the trailing edge (Fig. 10).
Weetman II does not disclose a doubly-curved configuration in which the blade curves along two mutually intersecting directions.
However, Weetman discloses a propeller where each blade comprises: A thrust side surface and a suction side surface (thereby creating axial flow, col. 2, line 8); an inner edge fixedly connected to the hub (Fig. 2, the edge attached to hub 18) and an outer edge located at a distance from the hub (surface comprising tip 24) as shown below:
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Weetman further teaches a doubly-curved configuration in which the blade curves along two mutually intersecting directions ( “directions” indicated by arrows) as shown below:
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Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein each blade comprises a doubly-curved configuration in which the blade curves along two mutually intersecting directions.
The person of ordinary skill in the art would have been motivated to shape the blade such that the blade increases in width from the tip and then decreases in width toward the hub (Weetman, col. 5, lines 65-67) to form a curve along the leading and trailing edges in order to increase efficiency (col. 6, lines 19-22) or otherwise would have found it obvious to select a known shape of a blade leading and trailing edge (a curved shape, Weetman, Fig. 2) resulting in a doubly-curved blade (Weetman II, tip 30 is also curved, Weetman, tip 24 is also curved) in order to achieve the predictable result of providing a blade suitable for use in circulating materials with suspended solids (Weetman II, Abstract, Weetman, Abstract).
Weetman II does not disclose an angle between the chord and a transverse plane of the propeller is equal to or greater than 35⁰ and equal to or less than 40⁰ in every imaginary intermediate geometrical plane spanning 70% of the radial distance. Rather, Weetman II discloses an angle of 37⁰ at the hub which remains in the range between 35⁰-40⁰ for at least 40% of the radial distance (col. 5, lines 23-28) and Weetman II discloses the twist (change in angle between hub and tip) may be 12⁰ (col. 5, line 24).
However, Weetman IV discloses a propeller and teaches using reduced twist (as low as 2⁰, Col. 3, lines 34-36, or 2-12⁰, col. 4, line 8).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein a twist angle of 2⁰ is utilized resulting in an angle between the chord and a transverse plane of the propeller being equal to or greater than 35⁰ and equal to or less than 40⁰ in every imaginary intermediate geometrical plane extending along a continuous range of at least 70% of the entirety of the radial distance the continuous range excluding at least the imaginary inner geometrical plane and the imaginary outer geometrical plane (using Weetman II’s hub angle of 37⁰ and Weetman IV’s teaching of a 2⁰ twist resulting in the angle being between 35-37⁰ over the entire radial distance).
The person of ordinary skill in the art would have been motivated to modify Weetman II by using the reduced twist of Weetman IV in order to achieve greater tip angles (tip chord angle (TCA)) and power numbers (Weetman IV, col. 3, lines 5-10) while maintaining efficiency (col. 3, lines 34-36).
Further, Engelbrecht et al. teaches that chord angle is selected to achieve a desired pumping rate (col. 5, lines 25-26) and Page teaches chord angle may be between 20-60⁰ at the hub (root, page 3, 3rd paragraph) and the tip angle may be between 0-44⁰ (page 3, 3rd paragraph).
Therefore, it would have also been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein an angle between the chord and a transverse plane of the propeller is selected which is equal to or greater than 35⁰ and equal to or less than 40⁰ in every imaginary intermediate geometrical plane spanning 70% of the radial distance to achieve a desired pumping rate and the proportions disclosed by Weetman II in view of Engelbrecht et al. and Page (Page, page 3, 3rd paragraph) overlap the instantly claimed proportions and therefore are considered to establish a prima facie case of obviousness. It would have been obvious to one of ordinary skill in the art to select any portion of the disclosed ranges including the instantly claimed ranges from the ranges disclosed in the prior art reference, particularly in view of the fact that:
“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.” See In re Peterson, 65 USPQ2d 1379 (CAFC 2003) and MPEP 2144.05.
Weetman II does not disclose wherein a ratio between an arc-height between the chord and the thrust side surface and the length of the chord is equal to or greater than 0.08 and equal to or less than 0.15 in each imaginary intermediate geometrical plane taken along the entirety of the radial distance and is greater than 0.12 in every imaginary intermediate geometrical plane extending along a continuous range of at least 60% of the entirety of the radial distance.
However, Hjorth et al. discloses a propeller (page 1, line 13) and discloses wherein the ratio between an arc-height between the chord and the thrust side surface and the length of the chord is 0.05 – 0.15 (page 2, line 52).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II to include wherein a ratio between an arc-height between the chord and the thrust side surface and the length of the chord is equal to or greater than 0.08 and equal to or less than 0.15 in each imaginary intermediate geometrical plane taken along the entirety of the radial distance and is greater than 0.12 in every imaginary intermediate geometrical plane extending along a continuous range of at least 60% of the entirety of the radial distance.
The person of ordinary skill would have found it obvious to use a ratio between 0.05 and 0.15, such as one greater than 0.12 (e.g. 0.12 – 0.15, Hjorth et al., page 2, line 52) to achieve efficient, but fully acceptable propeller function (Hjorth et al., page 2, lines 53-54).
One of ordinary skill in the art at the time the invention was made would have considered the invention to have been obvious because the proportions taught by Weetman II in view of Hjorth et al. overlap the instantly claimed proportions and therefore are considered to establish a prima facie case of obviousness. It would have been obvious to one of ordinary skill in the art to select any portion of the disclosed ranges including the instantly claimed ranges from the ranges disclosed in the prior art reference, particularly in view of the fact that:
“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.” See In re Peterson, supra and MPEP 2144.05.
Regarding claim 18, the combined teachings of the above-cited references for claim 15 disclose wherein the angle between the chord and the transverse plane of the propeller is in a range of 29-45 degrees in each imaginary intermediate geometrical plane along the entirety of the radial distance (such as an angle between 35-37⁰ as disclosed by Weetman II in view of Weetman IV, see claim 1 above).
Regarding claim 30, Weetman II does not expressly disclose each blade further comprises a uniform thickness over an entire extension of the blade.
However, Weetman teaches similar blades (shown above for claim 1) and Weetman further teaches wherein the thickness of the blade may vary or may be approximately equal throughout its length (col. 6, lines 28-35, where “length” reads on “extension”).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein each blade further comprises a uniform thickness over an entire extension of the blade.
The person of ordinary skill would have found it obvious to substitute one blade type (varying thickness over the length of the blade) for another known blade type (uniform thickness over the blade length, Weetman, col. 6, lines 28-35) and thereby achieve the predictable result of providing a blade for mixing liquids with suspended solids (Weetman II, Abstract, Weetman, Abstract). See KSR International Co. v. Teleflex Inc. (KSR), 550 U.S. 398, 82 USPQ2d 1385 (2007).
Further, Hjorth et al. further teaches using uniform thickness blades (page 1, lines 54-57) as an alternative to blade shapes having rounded streamlined shapes (page 1, lines 16-22).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein each blade further comprises a uniform thickness over an entire extension of the blade.
The person of ordinary skill in the art would have been motivated to use uniform thickness blades in order to achieve a simpler and more cost-efficient manufacturing process (Hjorth et al., page 1, lines 22-20).
Claims 16-17, 21-24, and 28-29 are rejected under 35 U.S.C. 103 as being unpatentable over Weetman et al. (US 5344235) hereinafter “Weetman II” in view of Weetman (US 5112192) hereinafter “Weetman”, Engelbrecht et al. (US 4231974), Hjorth et al. (GB 1454277), Weetman (US 5951162) hereinafter “Weetman IV”, and Page (attached WO 2008025975A1) as applied to claim 15 above and in further view of LJM Industrie (non-patent literature provided by the Applicant) hereinafter “LJM”.
Regarding claim 16, the above cited references for claim 15 are silent as to arc-height.
However, arc-height will depend on the chord length within the constraints of the camber (0.08-0.15 per claim 15) and chord length depends on the size of the blade. Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by sizing the propeller for use in a given tank size wherein it is sized to have an arc-height in the range of 30-70 mm in each imaginary intermediate geometrical plane along the entirety of the radial distance.
The person of ordinary skill in the art would have found it obvious scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., 725 F.2d 1338, 220 USPQ 777 (Fed. Cir. 1984), cert. denied, 469 U.S. 830, 225 USPQ 232 (1984).
Further, Weetman II in view of Hjorth et al. discloses a camber of 0.05 to 0.15 (Hjorth et al., page 2, line 52) and LJM teaches propellers for use in wastewater (title) wherein the propellers have concave and convex surfaces (photo on front page) and LJM further teaches the chord length could be 285 mm (table, page 5, col. G) which would correspond to a height of 34 mm for a camber of 0.12 or 43 mm for a camber of 0.15.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by using an arc-height in the range of 30-70 mm in each imaginary intermediate geometrical plane along the entirety of the radial distance, such as an arc height of 34 mm.
The person of ordinary skill would have found it obvious to use known dimensions of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid.
Regarding claim 17, the combined teachings of the above cited references for claim 15 are silent as to arc-height.
However, arc-height will depend on the chord length within the constraints of the camber (0.08-0.15 per claim 15) and chord length depends on the size of the blade. Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by sizing the propeller for use in a tank wherein the arc-height is in a range of 45-70 millimeters in a subset of the imaginary intermediate geometrical planes extending along a continuous range of at least 70% of the entirety of the radial distance, the continuous range excluding at least the imaginary inner geometrical plane and the outer geometrical plane (Weetman II, selecting planes from the infinite number of intermediate planes in a continuous range of at least 70% of the entirety of the radial distance excluding the outer and inner geometrical planes will still meet the claim limitation, such as by selecting the planes close to the hub in Weetman II).
The person of ordinary skill in the art would have found it obvious scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different size tanks. See In Gardner v. TEC Syst., Inc., supra.
Further, Weetman II in view of Hjorth et al. discloses a camber of 0.08 to 0.15 (Hjorth, page 2, line 52) and LJM teaches propellers for use in wastewater (title) wherein the propellers have concave and convex surfaces (photo on front page) and LJM further teaches the chord length could be 500 mm (table, page 9, col. G) which would correspond to a height of 60 mm for a camber of 0.12.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by using an arc-height in the range of 45-70 mm in a subset of the imaginary intermediate geometrical planes extending along a continuous range of at least 70% of the entirety of the radial distance, the continuous range excluding at least the imaginary inner geometrical plane and the imaginary outer geometrical plane, such as by using an arc-height of 60 mm.
The person of ordinary skill would have found it obvious to use a known dimensions of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid.
Regarding claim 21, the above cited references for claim 15 do not disclose a chord length.
However, chord length depends on the size of the blade and LJM teaches propellers for use in water treatment (title) and LJM teaches the propeller has concave and convex sides (photo on cover page) and therefore has a chord length. LJM further teaches the chord length may be 280 mm (page 5, table, col. G), 460 mm (page 9, table, col. G), etc.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein the length of the chord is in a range of 280-475 millimeters in each imaginary intermediate geometrical plane along the entirety of the radial distance.
The person of ordinary skill would have found it obvious to use a known dimension of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid or otherwise to scale the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., supra.
Regarding claim 22, the above cited references for claim 15 do not disclose a chord length.
However, chord length depends on the size of the blade and LJM teaches propellers for use in water treatment (title) and LJM teaches the propeller has concave and convex sides (photo on cover page) and therefore has a chord length. LJM further teaches the chord length may be 460 mm (page 9, table, col. G).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein the chord is sized to have a length in a range of 380-475 millimeters in each imaginary intermediate geometrical plane along a continuous range of at least 70% of the entirety of the radial distance, the continuous range excluding at least the imaginary inner geometrical plane and the imaginary outer geometrical plane (Weetman II, such as every plane between and parallel to the imaginary inner and outer geometrical planes or any parallel plane lying on an interval covering 70% of the radial distance).
The person of ordinary skill would have found it obvious to use a known dimension of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid and/or to scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., supra.
Regarding claim 23, Weetman II does not disclose actual dimensions for the leading edge.
As best understood, the dimension of Weetman II which reads on the claim limitation is shown (Weetman II, Fig. 4) annotated below (projected distance shown as dashed arrow):
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While Weetman II is silent as to this distance, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by sizing the propeller for use in a given tank size and thereby arrive at a length greater than 180 mm. Further, LJM teaches a propeller for water treatment (title) wherein a leading maximum projected distance in an axial direction of the propeller between two points on the leading edge is much greater than 180 millimeters (approximately half of distance D, page 13, figure and table).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein a leading maximum projected distance in an axial direction of the propeller between two points on the leading edge is equal to or greater than 180 millimeters.
The person of ordinary skill would have found it obvious to use a known dimension of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid and would have found it obvious to scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., supra.
Regarding claim 24, Weetman II does not disclose actual dimensions for the trailing edge.
As best understood, the dimension of Weetman II which reads on the claim limitation is shown (Weetman II, Fig. 4) annotated below:
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While Weetman II is silent as to this distance, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by sizing the propeller for use in a given tank size and thereby arrive at a length for the trailing edge dimension greater than 190 mm. Further, LJM teaches a propeller for water treatment (title) wherein a leading maximum projected distance in an axial direction of the propeller between two points on the leading edge is much greater than 180 millimeters (approximately half of distance D, page 13, figure and table).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein a trailing maximum projected distance in an axial direction of the propeller between two points on the trailing edge is equal to or greater than 190 millimeters.
The person of ordinary skill would have found it obvious to use a known dimension of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid and/or to scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., supra.
Regarding claim 28, Weetman II is silent as to the outer diameter.
While Weetman II is silent as to the outer diameter length, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II by sizing the propeller for use in a given tank size and thereby arrive at a length for the outer diameter less than 1350 mm. Further, LJM teaches a propeller for water treatment (title) wherein the outer diameter of the propeller is equal to or less than 1350 millimeters (such as 850 mm, page 11, figure distance D, Table, Col. D).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein the outer diameter of the propeller is equal to or less than 1350 millimeters.
The person of ordinary skill would have found it obvious to use a known dimension of a liquid-mixing propeller in order to achieve the predictable result of adequately mixing a liquid and/or to scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., supra.
Regarding claim 29, Weetman II does not expressly disclose a mixer.
However, LJM discloses a mixer for wastewater treatment (cover page and shown below) and “it is well-settled that the material worked upon by an apparatus does not limit apparatus claims. See MPEP 2115. Nonetheless, the mixer of LJM would be fully capable of functioning in a digestion tank with the propellor of the combined teachings of the above cited references for claim 15.
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Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II to further include a mixer for a digestion tank, the mixer comprising: a mixer body; a propeller shaft; and
the propeller of claim 15 connected to the propeller shaft.
The person of ordinary skill in the art would have found if obvious to use a propeller for mixing liquids (Weetman II, abstract) on a mixer having a propeller shaft and mixer body for use in a digester tank.
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Weetman et al. (US 5344235) hereinafter “Weetman II” in view of Weetman (US 5112192) hereinafter “Weetman”, Engelbrecht et al. (US 4231974), Hjorth et al. (GB 1454277), Weetman (US 5951162) hereinafter “Weetman IV”, and Page (attached WO 2008025975A1) as applied to claim 15 above and in further view of Heinzemann et al. (US 6082890), Fort et al. (previously attached non-patent literature), and Tsui et al. (previously attached non-patent literature).
Regarding claim 20, Weetman II discloses wherein the angle between the chord and the transverse plane of the propeller is in a range of 30-45 degrees in at least two of: (a) a subset of the imaginary intermediate geometrical planes along at least a continuous range of 95% of the entirety of the radial distance, the continuous range including the imaginary inner geometrical plane and (b) the imaginary inner geometrical plane (Weetman II, by selecting two planes near the hub as the “subset” of geometrical planes and both within a length covering 95% percent of the radial distance, the angle would be between 30-45 degrees, in that it would be close to 37 degrees, col. 5, line 23 and would be 37 degrees at the imaginary inner geometrical plane – at the hub).
Further, assuming arguendo that Weetman II does not disclose the limitation of an angle between 30-45 degrees as discussed above, Heinzemann et al. teaches an impeller for mixing fluid (col. 2, lines 55-60) with inside and outside blade angles relative to a vertical axis (α and β, Fig. 3) of 45 to about 60 degrees and 50 to about 70 degrees (abstract) which corresponds to 30-45 degrees and 20-40 degrees relative to a transverse plane, respectfully.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein the angle between the chord and the transverse plane of the propeller is in a range of 30-45 degrees in at least two of: (a) a subset of the imaginary intermediate geometrical planes along at least a continuous range of 95% of the entirety of the radial distance, the continuous range including the imaginary inner geometrical plane, (b) the imaginary inner geometrical plane, and (c) the imaginary outer geometrical plane (Heinzemann et al., (a), (b) and (c) as discussed above, Abstract).
One of ordinary skill in the art at the time the invention was made would have considered the invention to have been obvious because where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). It would have been obvious to one of ordinary skill in the art to select any portion of the disclosed ranges including the instantly claimed ranges from the ranges disclosed in the prior art reference, particularly in view of the fact that:
“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.” See In re Peterson, supra.
Further, Fort et al. teaches a mixing impeller having pitched blades and further teaches that “The higher the pitch angle, the lower the blending time” (page 11, left column) and for a lower pitch angle (such as 24 degrees with the transverse plane, Fig. 4) energy efficiency increases (page 12, right column) and Fort et al. further teaches the use of a blade angle of 35 degrees (page 12, left column) and Tsui et al. likewise teaches that “the power required to drive the impeller increases with the pitch angle of the blade” (page 780, right column) and further teaches a blade angle of 40 degrees (page 780, right column).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein the angle between the chord and the transverse plane of the propeller is in a range of 30-45 degrees in at least two of: (a) a subset of the imaginary intermediate geometrical planes along at least a continuous range of 95% of the entirety of the radial distance, the continuous range including the imaginary inner geometrical plane, (b) the imaginary inner geometrical plane, and (c) the imaginary outer geometrical plane.
The person of ordinary skill in the art would have found it obvious to select an angle between 30-45⁰ to achieve the desired balance between efficiency (Fort et al., page 12, right column. Tsui et al., page 780, right column), performance, and blending time (Fort et al., page 11, left column).
Claim 25 is rejected under 35 U.S.C. 103 as being unpatentable over Weetman et al. (US 5344235) hereinafter “Weetman II” in view of Weetman (US 5112192) hereinafter “Weetman”, Engelbrecht et al. (US 4231974), Hjorth et al. (GB 1454277), Weetman (US 5951162) hereinafter “Weetman IV”, and Page (attached WO 2008025975A1) as applied to claim 15 above and in further view of Commissariat Energie Atomique (Applicant provided WO 2017037156) hereinafter “CEA”.
Regarding claim 25, Weetman II does not disclose actual dimensions for a distance in an axial direction of the propeller between a trailing radial plane comprising the intersection between the inner edge and the trailing edge and a leading radial plane comprising the intersection between the outer edge and the trailing edge.
However, Weetman also teaches a propeller and further shows an axial distance between the intersection of transverse planes, the trailing edge, and the inner and outer edge as shown below:
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While Weetman is silent as to this distance, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II using the general shape taught by Weetman (insomuch as Weetman II does not expressly disclose this shape) above and to size the propeller for use in a given tank size to thereby arrive at a distance in an axial direction of the propeller between a trailing transverse plane comprising the intersection between the inner edge and the trailing edge and a leading transverse plane comprising the intersection between the outer edge and the trailing edge greater than 145 millimeters.
The person of ordinary skill in the art would have found it obvious scale the relative dimensions of the propeller up or down with the expectation of achieving the same performance for use in different sized tanks. See In Gardner v. TEC Syst., Inc., supra. The person of ordinary skill would have found it obvious to use a known shape for a propeller in order to achieve the predictable result of mixing liquid suspensions (Weetman, abstract).
Further, CEA discloses a propeller for mixing liquid (molten metal, abstract) and further teaches a distance Hp (Fig. 4c) is dependent on the height of the liquid in the container being stirred and may be about 400 mm (4 cm, para. [0041]) and based off the distance “Hp”, CEA reasonably discloses the distance in an axial direction of the propeller between a trailing transverse plane comprising the intersection between the inner edge and the trailing edge and a leading transverse plane comprising the intersection between the outer edge and the trailing edge is greater than 145 mm (at least greater than half the value of Hp or at least 200 mm) as annotated below:
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It is deemed that Weetman II in view of CEA reasonably disclose the axial distance between planes being greater the 145 mm (CEA, shown above). Assuming, arguendo, that the distance is not disclosed, the examiner has found that the specification contains no disclosure of any unexpected results arising therefrom, and that as such the parameters are arbitrary and therefore obvious. Such unsupported limitations cannot be a basis for patentability, because where patentability is said to be based upon particular chosen parameters or upon another variable recited in a claim, the applicant must show that the chosen parameters/variables are critical. See In re Woodruff, 919 F.2d 1575, 1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990) and MPEP 2144.05(III).
Claims 26-27 are rejected under 35 U.S.C. 103 as being unpatentable over Weetman et al. (US 5344235) hereinafter “Weetman II” in view of Weetman (US 5112192) hereinafter “Weetman”, Engelbrecht et al. (US 4231974), Hjorth et al. (GB 1454277), Weetman (US 5951162) hereinafter “Weetman IV”, and Page (attached WO 2008025975A1) as applied to claim 15 above and in further view of the Handbook of Industrial Mixing (attached non-patent literature) hereinafter “the Handbook”.
Regarding claims 26-27, insomuch as Weetman II does not expressly disclose the hub and the blades comprise metal, the Handbook teaches various axial flow impellers having different blade pitches to change pumping rate and thrust including propellers with a hub (Fig. 6-9, page 355). The Handbook further teaches the hub may be metal (implied by “welding” and “casting, page 1311, section 21-7.2) and that mixer wetted parts, which would include the hub and blades for a propeller designed for use in a liquid (Weetman II, abstract), are commonly made of stainless steel (page 1320, table 21-13).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified the teachings of Weetman II wherein the blades and hub comprise a metal comprising stainless steel.
The person of ordinary skill in the art would have found it obvious to use known and commonly used materials for constructing the hub and blades as “it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. See In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960); Sinclair & Carroll Co., Inc. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945).”
Conclusion
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/P.M.M./Examiner, Art Unit 1774
/CLAIRE X WANG/Supervisory Patent Examiner, Art Unit 1774
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