DETAILED ACTION
Response to Amendment
The Amendment filed September 29, 2025 has been entered. Claims 1 – 17 are pending in the application. The amendment to the claims has overcome all of the claim objections, except few (noted below), set forth in the last Non-Final Action mailed June 4, 2025.
Claim Objections
Claims 15 and 16 are objected to because of the following informalities:
Claims 15 and 16, line 1: “the pump” should read --the submersible pump--. This is suggested to distinguish the phrase from recited/claimed pump unit in claim 1.
Appropriate correction is required.
Claim Interpretation
The limitation “a dosing unit” in claim 1 is interpreted under 35 U.S.C. 112(f) as noted in the last office action.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1 – 17 are rejected under 35 U.S.C. 103 as being unpatentable over Felix et al. (US 2020/0340480 – herein after Felix) in view of Sande et al. (NO 341049B1 – herein after Sande).
In reference to claim 1, Felix teaches a submersible pump (1; see fig. 4) for conveying a process fluid (see ¶96; “process fluid” = fluid pumped by pump unit 3) and configured to be completely immersed in an environmental fluid (see ¶10; “environmental fluid” = seawater), the pump comprising:
a common housing (2, see fig.4 & ¶44) having a first compartment (space within “drive housing” in view of disclosure in ¶44) configured to be filled with a dosing fluid (fluid that acts as a coolant; viewed as fluid indicated by arrow C71 in fig. 4 and in view of disclosure in ¶90), and a second compartment (space within “pump housing” in view of disclosure in ¶44) configured to be filled with the process fluid, a first flow passage (via bearing 53, see fig. 4) is disposed between the first compartment (viewed as space in housing 2 above 53, in view of fig. 4) and the second compartment (viewed as space in housing 2 below 53, in view of fig. 4);
a pump unit (3, see ¶44 and fig. 4) arranged in the common housing (2);
a drive unit (4, see ¶44 and fig. 4) arranged in the common housing (2),
the common housing comprising an inlet (21, see ¶48 and fig. 4) and an outlet (22, see ¶48 and fig. 4) for the process fluid,
the pump unit comprising a pump shaft (5, see ¶49 and fig. 4) extending from a drive end (51) to a non-drive end (52) of the pump shaft and configured to rotate about an axial direction (A), and a hydraulic unit having at least one impeller (31, see ¶50 and fig. 4) fixedly mounted on the pump shaft to convey the process fluid from the inlet to the outlet,
the drive unit comprising a drive shaft (42, see ¶67 and fig. 4) connected to the drive end of the pump shaft to drive rotation of the pump shaft, and an electric motor (41, see ¶67 and fig. 4) configured to rotate the drive shaft about the axial direction,
the electric motor arranged inside the first compartment and the hydraulic unit arranged inside the second compartment (as evident from fig. 4), and the pump is a seal-less pump without a mechanical seal at the pump shaft and the drive shaft (see ¶17).
Felix remains silent on the submersible pump comprising “a dosing unit (i.e. a positive displacement pump; see “claim interpretation” above) configured to receive the environmental fluid, and provide the dosing fluid from the environmental fluid, and the dosing unit configured to dose a presettable amount of the dosing fluid into the first compartment and through the first flow passage into the second compartment”.
However, Sande teaches a similar submersible pump system comprising a dosing unit [7, see fig. 2; see page 4, lines 31-38: “A barrier fluid circuit 7 supplies barrier fluid to the motor and motor compartment at a pressure which is higher than the pressure of the processed fluid at discharge from the pump, this way allowing bleed of barrier fluid into the pump cavity via the seals 5 while preventing flow in the opposite direction, thus preventing ingress of process fluid and foreign matter into the motor compartment. Barrier fluid may be supplied from a topside barrier fluid source or from a submerged barrier fluid source into the barrier fluid circuit 7 via the proper valves, pressure regulators and pumps as is known in the art”] configured to receive the environmental fluid (water), and provide the dosing fluid [barrier fluid; note that “dosing fluid” = fluid provided/metered by pump and as an example (see page 3, lines 9-10), it is disclosed as a mixture of “water and glycol”; however, Sande states (see page 3, lines 10-12) “Also other types of barrier fluids can be selected that may have even better cooling properties”] from the environmental fluid (water), and the dosing unit configured to dose a presettable amount of the dosing fluid (barrier fluid) into the first compartment (motor compartment 3) and through the first flow passage (in partition wall 21) into the second compartment (pump compartment 4; also in fig. 2, barrier fluid flow direction from the first compartment into the second compartment is indicated by ↓ arrows).
Felix teaches the submersible pump (in embodiment of fig. 4) that utilizes portion of the process fluid provided in a cooling loop (10’) to cool/lubricate desired components in the submersible pump. Sande teaches the submersible pump that utilizes barrier fluid to cool/lubricate desired components in the submersible pump, wherein the barrier fluid is provided using improved barrier fluid circuit which comprises cooler (12), valves (schematically shown in fig. 2), pressure regulator (schematically shown in fig. 2) and pump (schematically shown in fig. 2). Therefore, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to modify the submersible pump of Felix for utilizing barrier fluid circuit as taught by Sande for the purpose of providing an improved cooling and barrier fluid system in a subsea motor and pump or compressor assembly, as recognized by Sande (see page 2, lines 26-28) [note that Sande further discussed advantages of this system on page 7, lines 3-7]. The modification is viewed as “removal/closing of passage with fluid flow C7 in Felix and coupling Sande’s barrier fluid circuit to Sande’s fluid flow passages 101 & 102” [note that Sande’s cooler 12, which is part of the barrier fluid circuit, could be disposed externally around Felix’s motor compartment and Sande’s circulation impeller 18 is accordingly coupled to top end of Felix’s motor shaft for circulation of barrier fluid through Sande’s cooler 12].
Thus, Felix, as modified by Sande, teaches the submersible pump, comprising a dosing unit (using teaching of Sande) configured to receive the environmental fluid, and provide the dosing fluid from the environmental fluid, and the dosing unit configured to dose a presettable amount of the dosing fluid into the first compartment (space within “drive housing” in view of disclosure in ¶44 of Felix) and through the first flow passage (via bearing 53, see fig. 4 of Felix) into the second compartment (viewed as space in housing 2 below 53, in view of fig. 4 of Felix).
“Dosing unit” involves use of a positive displacement pump (see claim interpretation above). Sande discloses (see page 4, lines 35-38): “Barrier fluid may be supplied from a topside barrier fluid source or from a submerged barrier fluid source into the barrier fluid circuit 7 via the proper valves, pressure regulators and pumps as is known in the art”. Thus, Felix, as modified by Sande, remains silent on the pump being a positive displacement pump.
However, “positive displacement pumps” are well known in the art. Applicant in the filed specification (see ¶82 of filed specification) has not disclosed any criticality or unexpected results in the filed specification with respect to having the dosing unit in the form of a positive displacement pump. Thus, in absence of any criticality, the mere selection of a specific type of pump (positive displacement) from the broader disclosure of “pumps as is known in the art” in Sande would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention in the modified pump of Felix as a matter of design choice. One of ordinary skill in the art, furthermore, would have expected modified Felix’s submersible pump to perform equally well with claimed dosing unit comprising a positive displacement pump.
In reference to claim 2, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) the first compartment (space above 53) is arranged adjacent to the second compartment (space below 53) with respect to the axial direction (↨ direction), a first partition wall (wall in which bearing 53 is disposed) is disposed between the first compartment and the second compartment, the first flow passage (present in view of fluid flowing through bearing 53; see fluid arrow C73) is arranged in the first partition wall, and (as evident from fig. 4) the pump shaft (5) or the drive shaft extends through the first flow passage.
In reference to claim 3, Felix, as modified, teaches the submersible pump, further comprising (see fig. 4 of Felix and ¶61) a balance drum (7) fixedly connected to the pump shaft (5) between the hydraulic unit (31) and the drive end (51) of the pump shaft (5), a relief passage (73) is disposed between the balance drum and a stationary part (26) configured to be stationary with respect to the common housing, and a balance line (9, see ¶64) is configured to return the process fluid passing through the relief passage to a low pressure location of the pump unit.
In reference to claim 4, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) further comprising a first pump bearing unit (53, see ¶57) and a second pump bearing unit (54, see ¶57) to support the pump shaft (5), and a first motor bearing unit (44, see ¶67) and a second motor bearing unit (43, see ¶67) to support the drive shaft (42), the first pump bearing unit (53) is arranged between the hydraulic unit (31) and the drive end (51) of the pump shaft (5), the second pump bearing unit (54) is arranged between the hydraulic unit (31) and the non-drive end (52) of the pump shaft (5), and the electric motor (41) is arranged between the first motor bearing unit (44) and the second motor bearing unit (43) in the axial direction (A).
In reference to claim 5, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) the first pump bearing unit (53), the second pump bearing unit (54), the first motor bearing unit (44) and the second motor bearing unit (43) are each configured to be lubricated by the process fluid or by the dosing fluid (capable of being lubricated by dosing fluid in the modified pump of Felix; this is further evident from Felix’s fig. 4).
In reference to claim 6, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) the first pump bearing unit (53) and the second pump bearing unit (54) are arranged in the second compartment (in this case, “second compartment” is viewed as space in housing 2 below coupling 8 in fig. 4).
In reference to claim 7, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) the first motor bearing unit (44) and the second motor bearing unit (43) are arranged in the first compartment (in this case, “first compartment” is viewed as space in housing 2 above bearing 53 in fig. 4).
In reference to claim 8, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) the first pump bearing unit (53), the first motor bearing unit (44) and the second motor bearing unit (43) are arranged in the first compartment (in this case, “first compartment” is viewed as space in housing 2 above port 91 in fig. 4).
In reference to claim 9, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix) the common housing (2) comprises a third compartment (space below 54) configured to be filled with the dosing fluid (coolant), the second compartment (space in housing 2 between bearing 53 and bearing 54) is arranged in the axial direction (A) between the first compartment (space in housing 2 above bearing 53) and the third compartment (space in housing 2 below bearing 54), a second flow passage (present in view of fluid flowing through bearing 54; see fluid arrow C72) is disposed between the third compartment and the second compartment, the dosing unit (provided using the teaching of Sande) is configured to dose an amount of the dosing fluid into the third compartment and through the second flow passage into the second compartment, and the second pump bearing unit is arranged in the third compartment.
In reference to claim 10, Felix, as modified, teaches the submersible pump, (see fig. 4 of Felix) wherein a second partition wall (wall in which bearing 54 is disposed) is disposed between the third compartment and the second compartment, the second flow passage (present in view of fluid/coolant flowing through bearing 54; see fluid arrow C72) is arranged in the second partition wall, and the pump shaft (5) extends through the second flow passage.
In reference to claim 11, Felix, as modified, teaches the submersible pump, (see the proposed modification discussed above in claim 1, fig. 4 of Felix and fig. 2 of Sande) further comprising an external cooling loop (12; of Sande) configured to cool and lubricate the drive unit (4; of Felix) by the dosing fluid, the external cooling loop comprising a heat exchanger (coil of pipes 13; of Sande) to cool the dosing fluid, the heat exchanger arranged outside the common housing (of Felix) and configured to receive the dosing fluid from the first compartment and to recirculate the dosing fluid to the first compartment (in view of disclosure by Sande on page 5, lines 27-38 and page 6, lines 1-9).
In reference to claim 12, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix and ¶32) the submersible pump is a vertical pump with the pump shaft (5) extending in the direction of gravity (↓ direction).
In reference to claim 13, Felix, as modified, teaches the submersible pump, wherein (see fig. 4 of Felix and ¶32) the drive unit (4) is arranged on top of the pump unit (3).
In reference to claim 14, Felix, as modified, teaches the submersible pump, wherein the submersible pump is a subsea pump (see ¶10 of Felix).
In reference to claim 15, Felix, as modified, teaches the submersible pump, wherein the submersible pump is a water injection pump configured to inject the process fluid (see ¶10 or ¶45 of Felix).
In reference to claim 16, Felix, as modified, teaches the submersible pump, wherein the submersible pump is a subsea pump configured to be installed on a sea ground (see ¶33 of Felix).
In reference to claim 17, Felix, as modified, teaches the submersible pump, wherein (see ¶34 or ¶45 of Felix) the process fluid is seawater, and the submersible pump is a water injection pump configured to inject the seawater into a subterranean region.
Response to Arguments
Applicant's arguments filed 09/29/2025 have been fully considered but they are not persuasive.
The Applicant asserts that the term “dosing unit” has a sufficiently definite meaning to one of ordinary skill in the art to avoid being construed under 35 USC 112(f). This argument is unpersuasive for following reasons:
Unlike “screwdrivers” or “clamps,” the term “unit” is a well-recognized generic placeholder that does not convey specific structure to a person of ordinary skill in the art. The modifier “dosing” describes the function of the unit (i.e. to dose a fluid) rather than providing a structural definition. As noted in the last Office Action, the specification itself defines this “unit” by its components – namely, a positive displacement pump and filtration/treatment apparatus – confirming that the term “dosing unit” is a functional shorthand for a collection of structures. Therefore, the term is properly interpreted under 35 USC 112(f) to cover the structures described in the specification and their equivalents. Furthermore, the term “dosing unit” is not a name for a single, well-recognized structural component in the pumping arts; rather, it is a functional designation. In the absence of a structural modifier preceding the generic placeholder “unit,” the limitation must be interpreted to cover the corresponding structure described in the specification.
The Applicant contends that Sande fails to disclose a pump completely immersed in the same fluid used for dosing. They argue the barrier fluid in Sande is contained within a closed circuit (7), failing to suggest the pump is immersed in that specific fluid. This argument is unpersuasive for following reasons:
Felix explicitly teaches a submersible pump (1) configured to be completely immersed in an environmental fluid (seawater). In the field of subsea pumping, seawater is the universal environmental fluid. Furthermore, the claim requires a dosing unit “configured to receive environmental fluid” and “provide dosing fluid from the environmental fluid”. In patent examination, the phrase “configured to” denotes that the structure must possess the inherent capability to perform the recited function. Sande discloses a barrier fluid circuit (7) that includes “proper valves, pressure regulators and pumps”. Sande explicitly states that barrier fluid is supplied from a “topside or submerged barrier fluid source” (see page 4, lines 35-38). If the pump is a “subsea pump” completely immersed in an “environmental fluid” (such as seawater, as taught in Felix), then a “submerged source” is, by definition, located within that same environmental fluid. Sande teaches a barrier fluid circuit (7) where the barrier fluid can be “a mixture of water and glycol” or “other types of barrier fluids” (see page 3, lines 9-12). For a pump immersed in seawater (environmental fluid), it is a well-known engineering capability to source that ambient water and process it to create the dosing/barrier fluid. A PHOSITA would recognize the inherent advantage of sourcing dosing fluid from the local environment to avoid the complexity of surface-to-sea umbilicals. Felix provides the physical state of immersion, while Sande provides the specific functional capability of the dosing unit to source fluid from a submerged (environmental) location and regulate its delivery into the motor compartment. The fact that Sande’s barrier fluid is contained in a circuit (7) does not negate its capability to receive that fluid from the surrounding environment.
Applicant argues that adding Sande’s barrier circuit to Felix would render Felix “unsatisfactory for its intended purpose” because Felix uses a relief passage (73) to allow process fluid to flow from the pump to the motor, whereas the invention requires the opposite. This argument is unpersuasive for following reasons:
The above argument is a mischaracterization of the obviousness standard. The legal test is not whether the specific physical structure of Felix can be modified without changing its internal flow paths, but whether the teachings of the references would make the claimed invention obvious. Sande explicitly teaches the benefit of maintaining higher pressure in the motor compartment to allow a “small amount of bleeding” into the process fluid to prevent ingress of process fluid and foreign matter into the motor (see page 1, lines 18-20 and page 4, lines 27-35). A PHOSITA would recognize that Felix’s seal-less design (see ¶17), which allows process fluid into the motor for lubrication, could be improved by Sande’s teaching of a pressurized barrier system to protect sensitive motor/drive components from potentially harsh or dirty process fluids. This is a matter of choosing between two known methods of motor protection/lubrication in subsea pumps. The modification is an application of Sande’s established method of protection to Felix’s established pump structure. It involves replacing Felix’s internal cooling loop (10’; which utilizes process fluid) with Sande’s barrier fluid circuit (7) and does not require the creation of new internal structures but rather the repurposing of existing ones taught by the references.
Applicant alleges the Examiner improperly switched “first” and “second” compartments between pages 2 and 6 of the Office Action. This argument is unpersuasive for following reasons:
The core of the “switching” argument relies on the fact that Felix and Sande use different reference numerals for their respective motor and pump compartments. However, the physical and functional layout is consistent across both. The legal standard for obviousness does not require a one-to-one match of reference numerals, but rather that the structure and function are taught. References alone or in combination clearly identifies a motor/drive compartment and a pump compartment. Whether they are labeled “same” or “different” is arbitrary; the structural relationship – fluid flowing from a dosing unit into one compartment and then through a passage into another – is clearly rendered obvious by Sande’s teaching of barrier fluid flowing from a circuit into a motor compartment and then through seals (5) into a pump cavity (4).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/CHIRAG JARIWALA/Examiner, Art Unit 3746
/BRYAN M LETTMAN/Primary Examiner, Art Unit 3746