DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 21 January 2026 has been entered.
Examiner notes that applicant has switched embodiments to a previously unexamined embodiment.
Claims 1, 5, and 7-9 are pending.
Claim Objections
Claims 1 and 9 are objected to because of the following informalities:
Claim 1 recites “the another” in lines 15 and 21. Claim 1 recites “another” to refer to selection of things from a group in lines (12, 15, 21). The word “another” is used in English to refer to “one more” or “an additional/different one of the same type.” In contrast the term “the other” is used to the remaining people/things in the group. Applicant is using the term to refer to the remaining things in the group. The term “the another’ and “another” should all be replaced with “the other” in order to use the word with the correct usage and definition in English.
Claim 9 makes the same error of claim 1 and uses “another” rather than “the other.” The term “the another’ and “another” should all be replaced with “the other” in order to use the word with the correct usage and definition in English.
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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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 1,5, and 7-9 are rejected under 35 U.S.C. 103 as being unpatentable over Alban (EP 2749771) in view of Okada (JP 2022155811, citations to machine translation).
Claim 1, Alban discloses a centrifugal pump (fig 1-4, par 0001) comprising: a rotating body (bladed hub portion 4, par 0032) including a rotor blade (bladed hub, id); a rotor shaft (10) disposed in a center of the rotating body (fig 4, 10 in center of 4); a magnetic bearing (axial bearing 11, 12, par 0082, axial bearings may be magnetic, par 0087) configured to levitate and support the rotor shaft (magnetic bearings conventionally function by levitating, par 0005-0008, 0087; fig 4 shows a gap distance between bearings 11, 12 and rotor 4 which suggests the conventional magnetic levitation support);
and
a bearing protection structure (fig 4, balance drum seal 21, par 0076-0078; seal 23 and seal 20, par 0061-0062) configured to protect the touchdown bearing (seal 21 generates axial forces which compensate for part of the axial load of the impeller, par 0061-0062, 0078, 0087; compensation of axial load reduces the axial forces that impact axial thrust bearings allowing them to be reduced, par 0087; under a BRI reducing axial forces is protection against said axial forces), wherein the bearing protection structure includes a protrusion (seals 19-23 are protrusions from the stationary side around the rotating body, and the following are protrusions on the rotating body at fig 1, 23, 32; fig 2, 25, 32; fig 3, 18, 32; fig 4, 18, 32) disposed on at least one of the rotating body (id.) and a component around the rotating body (id.),
the protrusion extending along an axial direction (the seals 21, 22, 23, 26 are distributed axially above and below the impeller channel) of the centrifugal pump and
having a first end and a second end (protrusion 21 and all other seals has clear radially inner and outer ends),
the first end being connected to the one of the rotating body and the component around the rotating body (an end of 21 connects to rotating body 4, and another end connects to stationary diagram 7),
the second end facing another of the rotating body and the component around the rotating body (the other end of 21 contacts the other of 4 and 7) in the axial direction of the centrifugal pump (fig 3, 4 shows 21 fastened axially to 7; and an axial contact causing a bend between 21 and rotor 4),
… upon touchdown of the rotor shaft on the touchdown bearing (fig 4 shows a gap distance between rotor and magnetic bearing 12 were seal contact between 21 and 18 would continue if the rotor was sitting on magnetic bearings 21),
the another of the rotating body and the component around the rotating body comes into contact with the second end (the outer end of 21 is fixed to the diaphragm 7 which is in contact with the rotating body; rotor 4, rotating body is in contact with the inner tip of 21) so that kinetic energy of the rotating body acting on the touchdown bearing is reduced (21 reduces axial force on the bearing, par 0078; the reduction of axial force reduces the axial force between the rotor and the component around the rotor; since axial force is reduced it inherently reduces kinetic energy which results from the application of that axial force),
and
when no touchdown occurs (fig 4 shows the arrangement when the rotor is levitated by the magnetic bearing 12 and therefore not in a touchdown state), a clearance is present between the second end and the another of the rotating body and the component around the rotating body (fig 3 and fig 4 shows that the rotating body on the radial inner side of 21 is separated from the component around the rotating body by a radial clearance that is the width of seal 21),
at a back side of the rotating body (fig 3, the backside of 4 closer to seal 21),
a back plate (diaphragm 7) is disposed as the component around the rotating body (7 surrounds rotor 4) or a part of the component around the rotating body (id) to prevent disturbance of exhaust gas (seal 21 and diaphragm 7 prevent exhaust gas from leaking, 0077-0078), and the protrusion is disposed on at least one of a back surface of the rotating body and the backplate (seal 21 contacts the back surface of the rotor body at 18 and the back plate at 7, par 0076 ).
Alban is silent on a touchdown bearing that is separated, by a gap, from the rotor shaft and configured to support the rotor shaft when the magnetic bearing is uncontrollable.
Okada teaches a centrifugal compressor with a levitating magnetic bearing (magnetic bearing, pg 1) and a mechanical touchdown bearing (inner ring that prevents contact between shaft and magnetic bearing, pg 1, 3) configured to support the rotor when the magnetic bearing is not supporting the rotor (pg 3 paragraph 5, pg 4, paragraph 4).
It would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the bearing structure of Alban by adding the auxiliar touchdown bearing (15) of Okada in order for the auxiliary bearing (15) to support the rotor due to emergency stops such as power loss (pg 4) and thereby reduce damage and contact between the magnetic bearing and shaft (pg 1).
Furthermore, Okada teaches that the auxiliar bearing is between the rotating shaft and the magnetic bearing (pg 3 second paragraph); it is therefore reasonably that in the combination the arrangement of bearings would be the same in order to retain the same function. Therefore, the auxiliar bearing would be impact first during a magnetic bearing failure because it is closer to the rotating body and therefore the first to be hit.
Claim 5, Alban in view of Okada teaches the centrifugal pump according to claim 1, wherein a storage portion (Alban, fig 3, the space above seal 21 and its connection to 18) is disposed at a position downstream of the protrusion to store contaminants created on contact between the rotating body and the component around the rotating body (fig 3 shows that protrusion 18 is downstream of the radially outside portion of seal 21, par 0076-0078; fig 3 shows a visible space between 21 and 18 which could reasonably collect contaminants in that area; reasonably a seal 21 which prevents gas flow and allows the disclosed pressure buildup would prevent particulate from passing the seal boundary).
Claim 7, Alban in view of Okada teaches the centrifugal pump according to claim 1, wherein the protrusion is provided in plurality (there is a plurality of seals 21-23, and 28 which act as protrusions and reduce axial load of the rotor thereby protecting axial bearings), and the plurality of protrusions are arranged at regular intervals in a circumferential direction (seals 21-23 and 28 are annular protrusions and thereby meets the plain meaning of arranged in a circumferential direction; par 0022, 0077, 0082; the seals are also distributed above and below rotor 4 to create the balance drum seal next to each rotor, which meets the plain meaning of regular interval because of their regular distribution with each rotor).
Claim 8, Alban in view of Okada teaches the centrifugal pump according to claim 1. Alban is silent on wherein the protrusion has a surface that has a lower friction property than those of the rotating body and the component around the rotating body.
Nevertheless, Alban does disclose that seals 21-23 and 28 are in continual sealing contact between the rotor 4 and diaphragms 6/7, which would suggest to a person of ordinary skill in the art that the seal have a coefficient of friction that would be sufficient to seal but not hinder rotation of the rotor 4.
Claim 9, Alban discloses a centrifugal pump (fig 1- 4, par 0001) bearing protection structure to be used in a centrifugal pump (pump, par 0001) to protect a … bearing (reduce axial force on the bearing, par 0087),
wherein the centrifugal pump includes: a rotating body (fig 4, 4) including a rotor blade (bladed hub 4, par 0032); a rotor shaft (10) disposed in a center of the rotating body (10 is in 4, fig 1-4); a magnetic bearing (fig 4, 11, 12, par 0082, 0087) that levitates and supports the rotor shaft;
…
the bearing protection structure includes a protrusion (seals 20-23 and 26, par 0076-0078, 0061-0062) disposed on at least one of the rotating body and a component around the rotating body (each seal contacts the rotor 4 and the outer diagrams 6 or 7), the protrusion extending along an axial direction of the centrifugal pump (seals are distributed axially) and having a first end and a second end (each seal has inner and outer radial faces), the first end being connected to the one of the rotating body and the component around the rotating body (seal 21 has an end which connects to rotor 4 and another end that connects to the diaphragm 7), the second end facing another of the rotating body and the component around the rotating body in the axial direction of the centrifugal pump (seal 21 has another end which connects to rotor 4 and another end that connects to the diaphragm 7),
upon touchdown of the rotor shaft on the touchdown bearing (fig 4 shows a gap distance between rotor and magnetic bearing 12 were seal contact between 21 and 18 would continue if the rotor was sitting on magnetic bearings 21), the another of the rotating body and the component around the rotating body comes into contact with the second end (the outer end of 21 is fixed to the diaphragm 7 which is in contact with the rotating body; rotor 4, rotating body is in contact with the inner tip of 21) so that kinetic energy of the rotating body acting on the touchdown bearing is reduced (21 reduces axial force on the bearing, par 0078; the reduction of axial force reduces the axial force between the rotor and the component around the rotor; since axial force is reduced it inherently reduces kinetic energy which results from the application of that axial force),
and when no touchdown occurs (fig 4 shows the arrangement when the rotor is levitated by the magnetic bearing 12 and therefore not in a touchdown state), a clearance is present between the second end and the another of the rotating body and the component around the rotating body (fig 3 and fig 4 shows that the rotating body on the radial inner side of 21 is separated from the component around the rotating body by a radial clearance that is the width of seal 21),
at a back side of the rotating body (fig 3, the backside of 4 closer to seal 21), a back plate (diaphragm 7) is disposed as the component around the rotating body (7 surrounds 4) or a part of the component around the rotating body (id.) to prevent disturbance of exhaust gas (seal 21 and diaphragm 7 prevent exhaust gas from leaking, 0077-0078), and the protrusion is disposed on at least one of a back surface of the rotating body and the back plate (seal 21 contacts the back surface of the rotor body at 18 and the back plate at 7, par 0076 ).
Alban is silent on a touchdown bearing that is separated, by a gap, from the rotor shaft and configured to support the rotor shaft when the magnetic bearing is uncontrollable.
Okada teaches a centrifugal compressor with a levitating magnetic bearing (magnetic bearing, pg 1) and a mechanical touchdown bearing (inner ring that prevents contact between shaft and magnetic bearing, pg 1, 3) configured to support the rotor when the magnetic bearing is not supporting the rotor (pg 3 paragraph 5, pg 4, paragraph 4).
It would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the bearing structure of Alban by adding the auxiliar touchdown bearing (15) of Okada in order for the auxiliary bearing (15) to support the rotor due to emergency stops such as power loss (pg 4) and thereby reduce damage and contact between the magnetic bearing and shaft (pg 1).
Furthermore, Okada teaches that the auxiliar bearing is between the rotating shaft and the magnetic bearing (pg 3 second paragraph); it is therefore reasonably that in the combination the arrangement of bearings would be the same in order to retain the same function. Therefore, the auxiliar bearing would be impact first during a magnetic bearing failure because it is closer to the rotating body and therefore the first to be hit.
Response to Arguments
Applicant’s arguments with respect to claim(s) 1, 5, and 7-9 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
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/GEOFFREY S LEE/Examiner, Art Unit 3746 /DOMINICK L PLAKKOOTTAM/Primary Examiner, Art Unit 3746