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 .
Status of Claims
Claims 1–20 are pending and have been examined. Claims 1, 8 and 15 are independent. Claims 1–20 are rejected. Claims 17 and 19 are also objected to.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on January 29, 2024 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Objections
Claim 17 is objected to because of the following informalities: the phrase "flows into the immersion liquid through after being warmed" contains the extraneous word "through," and "the at least a portion of the second primary loop of liquid" does not match the antecedent recited in claim 16 ("the at least a portion of the second primary loop of cooled immersion liquid"). For examination, claim 17 is treated as reciting "the at least a portion of the second primary loop of cooled immersion liquid flows into the immersion liquid after being warmed by heat from the semiconductor chip package." Appropriate correction is required.
Claim 19 is objected to because of the following informality: "The data center of claim 18 coolant distribution unit comprises" appears to omit words. For examination, claim 19 is treated as reciting "The data center of claim 18 wherein the coolant distribution unit comprises." Appropriate correction is required.
Claim Interpretation
During examination, claims are given their broadest reasonable interpretation consistent with the specification. MPEP 2111.
"Coolant distribution unit" (claims 1–7, 12, 18, 19). Applicant's specification describes a coolant distribution unit as including a pump and a heat exchanger that cools warmed liquid returned from the immersion chamber (specification ¶0009), and in other embodiments as including two heat exchangers and two or more pumps (¶¶0020–0021, 0026, 0028). The specification does not require any particular housing or enclosure. Accordingly, a "coolant distribution unit" is construed as the pump(s) and heat exchanger(s) that cool the immersion liquid and distribute it to the recited outputs.
"Heat exchanger" (claims 2–6, 14, 19). Applicant's specification describes a heat exchanger as transferring heat from the primary-loop liquid to the liquid of a secondary loop (¶¶0009, 0021). The term is construed as a device that cools the immersion liquid by transferring its heat to another medium; a reference "cooler, such as a heat exchanger" meets the term.
"Secondary loop" (claims 9, 10, 19). Applicant's specification describes the secondary loop as the loop that receives heat from the heat exchanger and is coupled to a cooling tower and/or chilling unit (¶¶0009–0010). The term is construed accordingly.
"Cold plate" (claims 1, 8, 11, 15–17, 20). Applicant's specification describes the cold plate as mounted or otherwise mechanically coupled to the chip package, receiving cooled liquid through an inlet and releasing warmed liquid into the immersion bath (¶¶0016, 0038–0039). A plate-like cooling structure mounted on a heat-generating device and receiving a flow of liquid meets the term. The "floor" of the cold plate (claim 16) is construed as the wall of the cold plate that receives heat from the underlying chip package (¶0038).
"Immersion liquid" in the first and second primary loops (claims 1, 15). Consistent with the specification, the liquid of both loops is the liquid of the immersion bath (¶0016).
Claim 8 recites "cooling the second primary loop to a cooler temperature than the first primary loop, and/or, pumping the second primary loop to a higher flow rate than the first primary loop." The step is met by prior art that teaches either alternative.
None of the claim limitations uses the word "means" or a generic placeholder coupled with functional language; 35 U.S.C. 112(f) is not invoked. MPEP 2181.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 4 and 6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Gao, US 2023/0084765 A1 ("Gao").
Regarding claim 1, Gao discloses an apparatus (immersion cooling system, FIG. 2, ¶¶0018–0019) comprising:
a coolant distribution unit (pump 225 and heat exchanger 230, FIG. 2, ¶0019; see Claim Interpretation) comprising a first primary loop output to provide first cooled immersion liquid to an immersion chamber (the line delivering cooled coolant from heat exchanger 230 through inlet port 222 and supply panel 220 into bath 215 of enclosure 205, FIG. 2, ¶¶0019–0020) and a second primary loop output to provide second cooled immersion liquid to one or more cold plates within the immersion chamber (the second supply line delivering cooled liquid from heat exchanger 230 through second inlet port 242 to manifold 240, which feeds cooling plates mounted on devices inside the bath through flexible hoses, FIG. 2, ¶¶0019–0020, 0024; the liquid exits the cooling plates and mixes with the bath, ¶¶0018, 0020).
Regarding claim 4, Gao discloses wherein the coolant distribution unit comprises a heat exchanger and wherein the first primary loop output and the second primary loop output are coupled to an output of the heat exchanger (cooled coolant from heat exchanger 230 is supplied both to inlet port 222 and, by the second supply line, to inlet port 242, FIG. 2, ¶0019).
Regarding claim 6, Gao discloses wherein the coolant distribution unit comprises a warmed fluid input and wherein the first primary loop output and the second primary loop output are coupled downstream from the warmed fluid input (hotter liquid from the top of the tank is pumped through outlet port 224 by pump 225 to heat exchanger 230, from which both supply lines are fed, FIG. 2, ¶0019).
Claims 1 and 4–6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Chehade et al., US 2022/0322562 A1 ("Chehade").
Regarding claim 1, Chehade discloses an apparatus (cooling system 100, FIG. 2, ¶¶0049, 0054) comprising:
a coolant distribution unit (pumps 140 and 150, heat exchanger 180 and piping arrangements 160 and 170, FIG. 2, ¶¶0050–0051, 0054; see Claim Interpretation) comprising a first primary loop output to provide first cooled immersion liquid to an immersion chamber (first outlet 175 of piping arrangement 170, which returns the first fraction of dielectric cooling liquid 120 to container 110 after it has passed heat exchanger 180, FIG. 2, ¶¶0051, 0054) and a second primary loop output to provide second cooled immersion liquid to one or more cold plates within the immersion chamber (outlet 154 of pump 150, which receives the second fraction from second outlet 177 and forwards it to piping arrangement 190, manifold 192 and outlet pipes 194 to the inlets of thermal transfer devices 400, also called cold plates, mounted on processors 132 of the immersed electronic components in container 110, FIGS. 1–2, ¶¶0052–0054).
Regarding claim 4, Chehade discloses wherein the coolant distribution unit comprises a heat exchanger and wherein the first primary loop output and the second primary loop output are coupled to an output of the heat exchanger (heat exchanger 180 on piping arrangement 160 upstream of pump 140, whose output feeds both first outlet 175 and second outlet 177, FIG. 2, ¶¶0051, 0054).
Regarding claim 5, Chehade discloses at least one second primary loop pump coupled between the heat exchanger output and the second primary loop output (pump 150, receiving the second fraction from second outlet 177 downstream of heat exchanger 180 and delivering it through its outlet 154, FIG. 2, ¶¶0051, 0053–0054).
Regarding claim 6, Chehade discloses wherein the coolant distribution unit comprises a warmed fluid input and wherein the first primary loop output and the second primary loop output are coupled downstream from the warmed fluid input (inlet 162 of piping arrangement 160 withdraws both fractions of the warmed liquid from upper part 112 of container 110, upstream of heat exchanger 180 and of both outputs, FIG. 2, ¶¶0053–0054).
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; and (4) considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 2, 3 and 8–14 are rejected under 35 U.S.C. 103 as being unpatentable over Gao.
Regarding claim 2, Gao discloses the apparatus of claim 1 as set forth above, including a first heat exchanger coupled to the first primary loop output (heat exchanger 230, FIG. 2, ¶0019). In the FIG. 2 embodiment the single heat exchanger feeds both outputs, and Gao does not disclose in that embodiment a second heat exchanger coupled to the second primary loop output.
In its FIG. 5 embodiment, however, Gao supplies the manifold that feeds the cooling plates at a different temperature from that provided by the main cooler, using a secondary cooler 537 that may be a booster cooler receiving the cooled coolant from main cooler 530 and further cooling it (FIG. 5, ¶¶0032–0033). The main cooler is a heat exchanger (¶0032), and the secondary cooler likewise cools the coolant to its own set temperature, with its own external connections (FIG. 5, ¶0033).
It would have been obvious to one of ordinary skill in the art before the effective filing date to place Gao's secondary cooler on the second supply line of the FIG. 2 system, so that the second primary loop output is coupled to a second heat exchanger. Gao teaches supplying the cold-plate liquid at a temperature different from the bath supply for exactly this localized supply (¶0033), and identifies localized cooling of hot spots on high-performance chips as the purpose of that supply (¶¶0017–0018).
Regarding claim 3, Gao as modified teaches wherein an output of the first heat exchanger is coupled to an input of the second heat exchanger (the booster cooler receives the cooled coolant from the main cooler, FIG. 5 dash-dot arrow, ¶0033).
Regarding claim 8, Gao discloses a method (¶0037) comprising:
splitting immersion chamber fluid into a first primary loop and a second primary loop (liquid withdrawn from the tank through outlet port 224 is pumped through heat exchanger 230 and delivered along two supply lines, one to inlet port 222 and the other to inlet port 242, FIG. 2, ¶¶0018–0019);
pumping the first primary loop into an immersion bath within the immersion chamber (pump 225 drives the cooled liquid into bath 215 through inlet port 222 and supply panel 220, FIG. 2, ¶¶0019–0020); and,
pumping the second primary loop through at least one cold plate that is coupled to a semiconductor chip package within the immersion bath (the second supply line delivers cooled liquid through manifold 240 and hoses to cooling plates attached to the devices of the immersed boards, from which it is released into the bath, ¶¶0019–0020, 0024–0025; the devices are high-performance chips, ¶¶0004, 0017).
In the FIG. 2 embodiment both supply lines carry liquid from the same heat exchanger, and Gao does not disclose in that embodiment cooling the second primary loop to a cooler temperature than the first primary loop, and/or, pumping the second primary loop to a higher flow rate than the first primary loop. Gao's FIG. 5 embodiment supplies the cold-plate manifold at a different temperature by passing coolant already cooled by the main cooler through a booster cooler that further cools it (FIG. 5, ¶0033).
It would have been obvious to one of ordinary skill in the art before the effective filing date to add Gao's booster cooler to the second supply line of the FIG. 2 system, so that the second primary loop is cooled to a cooler temperature than the first, for the reasons given for claim 2 (¶¶0017–0018, 0033). Only the first alternative of the "and/or" step is relied upon (see Claim Interpretation).
Regarding claim 9, Gao as modified teaches cooling the first primary loop with a first secondary loop and cooling the second primary loop with a second secondary loop. Gao's heat exchanger rejects heat through a heat rejection loop such as an evaporative cooling tower, dry cooler or chilled water loop (¶0016), and FIG. 5 depicts main cooler 530 and secondary cooler 537 each with its own separate external inlet and outlet connection (FIG. 5; see MPEP 2125).
Regarding claim 10, Gao does not expressly disclose wherein the second secondary loop has a colder temperature than the first secondary loop. Gao, however, seeks a lower supply temperature for the cold-plate loop than for the bath loop by further cooling liquid that the main cooler has already cooled (¶0033), and lists a chilled water loop among the available heat rejection options (¶0016). The temperature to which a liquid-cooled heat exchanger can cool a fluid is bounded by the temperature of the coolant on its other side. It would therefore have been obvious to one of ordinary skill in the art before the effective filing date to couple Gao's booster cooler to a secondary loop colder than that of the main cooler, as the predictable way of obtaining the lower cold-plate supply temperature that Gao seeks. MPEP 2143(I)(A).
Regarding claim 11, Gao teaches pumping the second primary loop through a manifold that feeds multiple conduit lines to multiple respective cold plates that are mounted to respective semiconductor chip packages (manifold 240 or 540 with connectors feeding flexible hoses or lines 565, each connected to a cooling plate mounted on a respective device, FIGS. 2 and 5, ¶¶0020, 0024, 0033).
Regarding claim 12, Gao as modified teaches wherein the splitting is performed within a coolant distribution unit (the second supply line branches at the output of heat exchanger 230, which with pump 225 forms the coolant distribution unit, ¶0019; in the booster arrangement the secondary cooler draws from the main cooler's output, ¶0033).
Regarding claim 13, Gao teaches wherein the splitting is performed before the first primary loop is cooled and before the second primary loop is cooled (in the alternative arrangement, the secondary cooler receives coolant from outlet port 524 and cools it to its own set temperature, while the main cooler separately cools the bath supply, FIG. 5 solid arrow, ¶0033). It would have been obvious to use this alternative arrangement in the modified FIG. 2 system for the reasons given for claim 8.
Regarding claim 14, Gao teaches wherein the splitting is performed downstream from a heat exchanger that cools the first primary loop (the booster cooler receives the cooled coolant from the main cooler, FIG. 5 dash-dot arrow, ¶0033; in FIG. 2 both supply lines branch from the output of heat exchanger 230, ¶0019).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Gao in view of Campbell et al., US 2015/0109735 A1 ("Campbell").
Regarding claim 7, Gao discloses the apparatus of claim 1 as set forth above, in which pump 225 drives both the first and second primary loop outputs (FIG. 2, ¶0019). Gao does not disclose a first pump and a second redundant pump. Campbell discloses a coolant distribution unit whose pump may be accompanied by a redundant second pump (coolant distribution unit 200, pump 215, FIG. 2, ¶0027), and redundant pumps coupled in parallel to pump dielectric fluid to immersion-cooled electronic assemblies (pumps 610, FIG. 6C, ¶0061). It would have been obvious to one of ordinary skill in the art before the effective filing date to provide Gao's pump with a redundant second pump, as Campbell teaches for coolant distribution units, with the predictable result of a backup pump to maintain coolant flow if one pump fails. MPEP 2143(I)(A).
Claims 15 and 18–20 are rejected under 35 U.S.C. 103 as being unpatentable over Gao in view of Cao et al., US 2020/0218676 A1 ("Cao").
Regarding claim 15, Gao discloses a data center (computing facility with a cluster section of immersion tanks, ¶0038; data center cooling of CPU servers and storage servers, ¶¶0002–0003) comprising:
an immersion chamber, the immersion chamber containing an immersion liquid (enclosure 205 containing bath 215, in which servers 210 are immersed, FIG. 2, ¶0019),
the immersion chamber comprising a first input that receives a first primary loop of cooled immersion liquid that flows into the immersion liquid (inlet port 222 and supply panel 220, through which cooled coolant enters the bath, FIG. 2, ¶¶0019–0020),
the electronics comprising a semiconductor chip package coupled to a cold plate (cooling plates attached to devices of the immersed boards, ¶0024; high-performance chips, ¶¶0004, 0017), the cold plate coupled to a conduit line that receives at least a portion of a second primary loop of cooled immersion liquid (flexible hose connecting each cooling plate to a connector of manifold 240, which receives the second supply line, FIG. 2, ¶¶0019–0020, 0024).
Gao does not disclose a network; a CPU pool coupled to the network; a memory pool coupled to the network; a mass storage pool coupled to the network, such that electronics from the CPU pool, the memory pool and/or the mass storage pool are immersed within the immersion liquid.
Cao discloses a data center environment of computing racks containing pooled compute drawers 908 and 910, a pooled storage drawer 912 and a pooled memory drawer 914, each connected to a top-of-rack switch 904, with the racks interconnected through their switches to network 920 (FIG. 9, ¶¶0069–0070).
It would have been obvious to one of ordinary skill in the art before the effective filing date to immerse the electronics of Cao's pooled compute, memory and storage drawers in Gao's immersion tank. Gao applies its cooling to data center hardware, expressly including CPU servers and storage servers (¶0003), in order to cool the hot spots of high-performance chips (¶0017). Cao's pooled drawers are a known data center arrangement of such hardware, and cooling them with Gao's system applies a known technique to a known arrangement ready for improvement, with predictable results. MPEP 2143(I)(D).
Regarding claim 18, Gao teaches wherein the data center further comprises a coolant distribution unit that provides the first primary loop of cooled immersion liquid and the second primary loop of cooled immersion liquid (pump 225 and heat exchanger 230 supplying both lines, FIG. 2, ¶0019).
Regarding claim 19, Gao teaches coolant distribution unit comprises a first heat exchanger to cool the first primary loop and a second heat exchanger to cool the second primary loop and wherein the first heat exchanger is coupled to a first secondary loop and the second heat exchanger is coupled to a second secondary loop (main cooler 530 and secondary cooler 537, each with its own separate external connections, FIG. 5, ¶¶0032–0033; heat rejection loop, ¶0016). It would have been obvious to use Gao's FIG. 5 cooler arrangement in the data center of claim 18 for the reasons given for claims 2 and 9.
Regarding claim 20, Gao teaches a manifold having an output coupled to the conduit line that provides a portion of the second primary loop of cooled immersion liquid to the conduit line, the manifold comprising other outputs that provide other portions of the second primary loop of cooled immersion liquid to other conduit lines that are coupled to other cold plates that are coupled to other semiconductor chip packages within the immersion liquid (manifold 240 or 540 with multiple connectors feeding hoses or lines 565 to cooling plates on respective devices, FIGS. 2 and 5, ¶¶0020, 0024, 0033).
Claims 16 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Gao in view of Cao, and further in view of Quon et al., US 5,316,075 ("Quon").
Regarding claim 16, Gao in view of Cao teaches the data center of claim 15 as set forth above. Gao's cooling plates receive the liquid through an inlet connector and pass it through a cavity of cooling channels (¶¶0024–0026). Gao does not disclose wherein the cold plate comprises an inlet that injects the at least a portion of the second primary loop of cooled immersion liquid directly on a floor of the cold plate that is coupled to the semiconductor chip package.
Quon discloses a liquid jet cold plate in which coolant enters through inlet 26 and issues from the nozzles of nozzle plate 14 as jets that discharge against underside 52 of mounting plate 16, directly beneath the area where semiconductor device 18 is mounted (FIG. 1; col. 2, ll. 40–48 and 55–64; col. 3, ll. 6–13 and 22–26).
It would have been obvious to one of ordinary skill in the art before the effective filing date to configure the inlet of Gao's cooling plate to inject the liquid directly onto the plate wall coupled to the chip package, as Quon teaches. Quon's perpendicular jets minimize the boundary layer and improve the heat transfer coefficient (col. 3, ll. 48–54), and allow jet patterns to correspond to the heat gain of the device (col. 2, ll. 4–8; col. 3, ll. 6–13), which serves Gao's stated purpose of localized hot-spot cooling (¶¶0017, 0024).
Regarding claim 17, Gao teaches wherein the cold plate has more than one outlet through which the at least a portion of the second primary loop of liquid flows into the immersion liquid through after being warmed by heat from the semiconductor chip package (as treated under Claim Objections) (cooling plate 352 or 552 with two outlet holes, one on each side, releasing the coolant into the bath, FIGS. 3A and 5, ¶¶0025, 0031). Gao states that, regardless of outlet design, the outlet releases the coolant to the bath (¶0031); the modified cold plate of claim 16 retains these outlets.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
US 2021/0185850 – immersion tank with direct liquid cooling loops of cold plates
US 8,203,842 – open flow cold plate within a liquid-tight enclosure
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ZHENGFU J FENG whose telephone number is (571) 272-2949. The examiner can normally be reached on Monday - Friday, 900am-530pm 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, JAYPRAKASH GANDHI can be reached at (571) 272-3740. 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.
/ZHENGFU J FENG/Primary Examiner, Art Unit 2841
October 14, 2026
