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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 05th, 2026 has been entered.
Response to Amendment
The amendment filed February 05th, 2026 has been entered. Claims 1-4, 7-9, 11-12, 17-20, 23, 26-27 and 31-34 remain pending in the application. Applicant’s amendments to the Claims have overcome each and every claim 112(b) rejection previously set forth in the Final Office Action mailed November 06th, 2025. However, the amendment has raised other issues detailed below.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1, 3, 7-9, 12, 17, 19, 23, 27, and 31-34 are rejected under 35 U.S.C. 103 as being unpatentable over Hart (US Patent No. 5,038,580), hereinafter Hart in view of Chen et al. (US Patent No. 6,467,284), hereinafter Chen.
Regarding claim 1, Hart discloses a heating, ventilation, and air conditioning (HVAC) system (Fig. 1) comprising:
an outdoor heat exchanger (Fig. 1, earth coils 11, 12, 13) operable as an evaporator in a heating mode to vaporize at least some of the refrigerant (Fig. 1; Col. 2, lines 53-62, The liquid refrigerant entering valve 8 flows through an orifice in the valve which reduces its pressure so that some flash gas as well as liquid flows in line 9 to the distributor 10 where the flow is equally divided among earth coils 11, 12, and 13 by means of distributor tubes. As the liquid refrigerant and flash gas enters evaporator lines 11a, 12a and 13a most is liquid refrigerant by weight. In the preferred embodiment, as heat is absorbed from the earth most of the liquid is vaporized in tubes 11b, 12b and 13b);
an indoor heat exchanger (Fig. 1, indoor coil 5) operable as the evaporator in a cooling mode to vaporize at least some of the refrigerant (Fig. 2; Col. 3, lines 49-53, The liquid and flash gas enters receiver 7 where liquid falls to the bottom and exits the receiver 7 through the entrance to line 6 leading to the bottom of indoor coil 5 where it evaporates thus cooling air passing around it);
one bi-flow thermostatic expansion valve (TXV) (Fig. 1, bi-directional balanced expansion valve 8) operable to expand a refrigerant in a first flow direction in the cooling mode (Fig. 2; Col. 2, lines 9-10, FIG. 2 is a schematic diagram of the apparatus with the four-way valve positioned in the cooling mode; Further the bi-directional balanced expansion valve 8 of Hart has the same structure as the claimed bi-flow thermostatic expansion valve and is capable of functioning in the manner claimed) and also in a second flow direction opposite the first flow direction in the heating mode (Fig. 1; Col. 2, lines 7-8, FIG. 1 is a schematic diagram of the apparatus with the four-way valve positioned in the heating mode; Col. 2, lines 53-56, The liquid refrigerant entering valve 8 flows through an orifice in the valve which reduces its pressure so that some flash gas as well as liquid flows in line 9 to the distributor 10; Further the bi-directional balanced expansion valve 8 of Hart has the same structure as the claimed bi-flow thermostatic expansion valve and is capable of functioning in the manner claimed);
a compressor (Fig. 1, compressor 1) comprising a compressor inlet (Fig. 1, suction line 19) and a compressor outlet (Fig. 1, discharge line 2), the compressor operable to flow the refrigerant through the outdoor heat exchanger, the indoor heat exchanger, and the bi-flow TXV in a refrigerant circuit (Col. 2, lines 32-37 and 52-56, a compressor 1 for compressing refrigerant vapor and discharging it, along with a small quantity of oil, into discharge line 2 leading to a reversing four-way valve 3 depicted in the heating mode position where the refrigerant is directed through line 4 to the indoor coil 5… a bi-directional balanced expansion valve 8. The liquid refrigerant entering valve 8 flows through an orifice in the valve which reduces its pressure so that some flash gas as well as liquid flows in line 9 to the distributor 10 where the flow is equally divided among earth coils 11, 12, and 13 by means of distributor tubes), wherein the one bi-flow TXV is adjustable to control the entire flow of the refrigerant from the compressor outlet, in both the first flow direction and the second flow direction (Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports);
a four-way valve (Fig. 1, four-way valve 3) in the refrigerant circuit and operable such that the compressor is operable to flow the refrigerant out of the compressor outlet and through the bi-flow TXV in the first flow direction in the cooling mode and that the compressor is operable to flow the refrigerant out of the compressor outlet and through the bi-flow TXV in the second flow direction in the heating mode (Col. 2, lines 31-37, Referring now to FIG. 1, a schematic of the heat pump and heat exchanger, a compressor 1 for compressing refrigerant vapor and discharging it, along with a small quantity of oil, into discharge line 2 leading to a reversing four-way valve 3 depicted in the heating mode position where the refrigerant is directed through line 4 to the indoor coil 5; Col. 3, lines 35-38, Referring now to FIG. 2 which depicts the flow of 35 refrigerant during the cooling operation, it is noted that the refrigerant flows in the opposite direction in the heating mode; Further, the four-way valve 3 of Hart has the same structure as the claimed four-way valve and is capable of functioning in the manner claimed);
an accumulator (Fig. 1, accumulator 16) in the refrigerant circuit before the compressor inlet (Fig. 1 of Hart depicts accumulator 16 to be disposed upstream of the suction line 19; Col. 3, lines 9-16, Vapor and oil from line 14 enter the reversing valve 3 and are directed to line 15 which is connected to the top of accumulator 16. In accumulator 16 any liquid refrigerant and oil are trapped and prevented from returning directly to the compressor. An orifice disposed at the bottom of the U tube 17 in the accumulator 16 slowly dispenses any oil or liquid refrigerant back to the compressor in a non-slugging manner);
a sensing bulb (Fig. 1, sensing bulb 18) positioned to sense temperature of the refrigerant (Col. 3, lines 16-22, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed) and operable to communicate a pressure to the bi-flow TXV based on the sensed temperature for operating the bi-flow TXV (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Further, the sensing bulb 18 of Hart has the same structure as the claimed sensing bulb and is capable of functioning in the manner claimed); and
an equalizer line (Fig. 1, equalizer line 20) having a first end in fluid communication with the bi-flow TXV and a second end in fluid communication with the compressor suction line downstream of the accumulator (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle) to balance the pressure communicated to the bi-flow TXV from the sensing bulb to operate the TXV (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Further, the equalizer line 20 of Hart has the same structure as the claimed equalizer line and is capable of functioning in the manner claimed);
wherein the sensing bulb and the equalizer line are operable to control the bi-flow TXV such that at least some of any liquid refrigerant is separated from vaporized refrigerant in the accumulator to lower the superheat of the refrigerant leaving the evaporator while maintaining a superheat of the refrigerant entering the compressor compared to not separating the refrigerant (Col. 3, lines 9-25, Vapor and oil from line 14 enter the reversing valve 3 and are directed to line 15 which is connected to the top of accumulator 16. In accumulator 16 any liquid refrigerant and oil are trapped and prevented from returning directly to the compressor. An orifice disposed at the bottom of the U tube 17 in the accumulator 16 slowly dispenses any oil or liquid refrigerant back to the compressor in a non-slugging manner. The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Col. 3, lines 60-67, The power head of expansion valve 8 is connected to the sensing bulb 18 by means of capillary tube 21. Sensing bulb 18 senses the temperature of the vapor in suction line 19 and equalizer line 20 senses the pressure in line 19 if superheat is high 6° - 7° F. the expansion valve 8 opens further, if the superheat is low 3° -5° F. the valve 8 will further close to restore superheat to a normal 5°-6° F; Further, accumulator 16, sensing bulb 18, and equalizer line 20 of Hart have the same structure as the claimed sensing bulb and the equalizer line and are capable of functioning in the manner claimed; Moreover, the function of an accumulator in a heat pump system to separate liquid and vapor phases of a refrigerant, and additional oil, allows for the heat pump system to operate at lower superheat temperatures in comparison to heat pump systems that do not have accumulators and is simply a function of the structure of an accumulator in a heat pump system).
However, Hart does not disclose the sensing bulb positioned to sense temperature of the refrigerant entering the accumulator.
Chen teaches the sensing bulb positioned to sense temperature of the refrigerant entering the accumulator (Fig. 1 of Chen depicts sensing bulb 48 to be disposed upstream of the accumulator 16).
Hart fails to teach the sensing bulb positioned to sense temperature of the refrigerant entering the accumulator, however Chen teaches that it is a known method in the art of heat pumps to include the sensing bulb positioned to sense temperature of the refrigerant entering the accumulator. This is strong evidence that modifying Hart as claimed would produce predictable results (i.e. operation control based on real-time sensor data to improve overall system efficiencies). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Hart by Chen and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of operation control based on real-time sensor data to improve overall system efficiencies.
Regarding claim 3, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), wherein the HVAC system is a variable refrigerant flow heat pump system (Hart, Col. 12, lines 12-15, A variable speed compressor may be used or two compressors using a common or connected crankcase may be used to accomplish the 2: 1 ratio in compressor displacement).
Regarding claim 7, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), wherein the bi-flow TXV is configurable to store refrigerant in the accumulator if there is a refrigerant charge imbalance in the refrigerant circuit (Hart, Col. 3, lines 9-16, Vapor and oil from line 14 enter the reversing valve 3 and are directed to line 15 which is connected to the top of accumulator 16. In accumulator 16 any liquid refrigerant and oil -are trapped and prevented from returning directly to the compressor. An orifice disposed at the bottom of the U tube 17 in the accumulator 16 slowly dispenses any oil or liquid refrigerant back to the compressor in a non-slugging manner; Further, the bi-directional balanced expansion valve 8 of Hart has the same structure as the claimed bi-flow thermostatic expansion valve and is capable of functioning in the manner claimed).
Regarding claim 8, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), further comprising an outdoor section comprising the outdoor heat exchanger and the bi-flow TXV (See annotated Fig. 1 of Hart below, outdoor section A).
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Regarding claim 9, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), further comprising an indoor section comprising the indoor heat exchanger and the bi-flow TXV (See annotated Fig. 1 of Hart below, indoor section B).
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Regarding claim 12, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), wherein the bi-flow TXV comprises a balanced port design (Hart, Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports).
Regarding claim 17, Hart discloses a method of operating a heating, ventilation, and air conditioning (HVAC) system (Fig. 1), comprising:
operating a four-way valve (Fig. 1, four-way valve 3) and operating a compressor (Fig. 1, compressor 1) in a cooling mode (Fig. 2; Col. 2, lines 9-10, FIG. 2 is a schematic diagram of the apparatus with the four-way valve positioned in the cooling mode) to flow a refrigerant (Col. 2, lines 32-37 and 52-56, a compressor 1 for compressing refrigerant vapor and discharging it, along with a small quantity of oil, into discharge line 2 leading to a reversing four-way valve 3 depicted in the heating mode position where the refrigerant is directed through line 4 to the indoor coil 5… a bi-directional balanced expansion valve 8. The liquid refrigerant entering valve 8 flows through an orifice in the valve which reduces its pressure so that some flash gas as well as liquid flows in line 9 to the distributor 10 where the flow is equally divided among earth coils 11, 12, and 13 by means of distributor tubes) out of a compressor outlet (Fig. 1, discharge line 2) and through an outdoor heat exchanger (Fig. 1, earth coils 11, 12, 13), one bi-flow thermostatic expansion valve (TXV) (Fig. 1, bi-directional balanced expansion valve 8), and an indoor heat exchanger (Fig. 1, indoor coil 5) in a first direction in a refrigerant circuit with the indoor heat exchanger operating as an evaporator (Fig. 2; Col. 3, lines 49-53, The liquid and flash gas enters receiver 7 where liquid falls to the bottom and exits the receiver 7 through the entrance to line 6 leading to the bottom of indoor coil 5 where it evaporates thus cooling air passing around it);
operating the four-way valve and operating the compressor in a heating mode (Fig. 1; Col. 2, lines 7-8, FIG. 1 is a schematic diagram of the apparatus with the four-way valve positioned in the heating mode) to flow the refrigerant out of the compressor outlet and through the indoor heat exchanger, the one bi-flow TXV, and the outdoor heat exchanger in a second direction, opposite the first direction, in the refrigerant circuit with the outdoor heat exchanger operating as the evaporator (Fig. 1; Col. 2, lines 31-37, Referring now to FIG. 1, a schematic of the heat pump and heat exchanger, a compressor 1 for compressing refrigerant vapor and discharging it, along with a small quantity of oil, into discharge line 2 leading to a reversing four-way valve 3 depicted in the heating mode position where the refrigerant is directed through line 4 to the indoor coil 5; Col. 2, lines 53-62, The liquid refrigerant entering valve 8 flows through an orifice in the valve which reduces its pressure so that some flash gas as well as liquid flows in line 9 to the distributor 10 where the flow is equally divided among earth coils 11, 12, and 13 by means of distributor tubes. As the liquid refrigerant and flash gas enters evaporator lines 11a, 12a and 13a most is liquid refrigerant by weight. In the preferred embodiment, as heat is absorbed from the earth most of the liquid is vaporized in tubes 11b, 12b and 13b); and
controlling the entire refrigerant flow out of the evaporator, in both the first direction and the second direction, using the one bi-flow TXV (Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports; Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Col. 3, lines 60-67, The power head of expansion valve 8 is connected to the sensing bulb 18 by means of capillary tube 21. Sensing bulb 18 senses the temperature of the vapor in suction line 19 and equalizer line 20 senses the pressure in line 19 if superheat is high 6° - 7° F. the expansion valve 8 opens further, if the superheat is low 3° -5° F. the valve 8 will further close to restore superheat to a normal 5°-6° F), wherein the one bi-flow TXV is operable to expand the refrigerant in the first direction in the cooling mode and also in the second direction in the heating mode (Fig. 2; Col. 2, lines 9-10, FIG. 2 is a schematic diagram of the apparatus with the four-way valve positioned in the cooling mode; Fig. 1; Col. 2, lines 7-8, FIG. 1 is a schematic diagram of the apparatus with the four-way valve positioned in the heating mode; Col. 2, lines 53-56, The liquid refrigerant entering valve 8 flows through an orifice in the valve which reduces its pressure so that some flash gas as well as liquid flows in line 9 to the distributor 10; Further the bi-directional balanced expansion valve 8 of Hart has the same structure as the claimed bi-flow thermostatic expansion valve and is capable of functioning in the manner claimed),
wherein controlling the entire refrigerant flow using the bi-flow TXV further comprises:
collecting any of the refrigerant in a liquid state in an accumulator located in the refrigerant circuit before a compressor inlet to lower a superheat of the refrigerant leaving the evaporator compared to not including the accumulator (Fig. 1 of Hart depicts accumulator 16 to be disposed upstream of the suction line 19; Col. 3, lines 9-16, Vapor and oil from line 14 enter the reversing valve 3 and are directed to line 15 which is connected to the top of accumulator 16. In accumulator 16 any liquid refrigerant and oil -are trapped and prevented from returning directly to the compressor. An orifice disposed at the bottom of the U tube 17 in the accumulator 16 slowly dispenses any oil or liquid refrigerant back to the compressor in a non-slugging manner) such that the bi-flow TXV may be configured to lower a superheat of the evaporator compared to not including the accumulator (the bi-directional balanced expansion valve 8 of Hart has the same structure as the claimed bi-flow thermostatic expansion valve and is capable of functioning in the manner claimed);
sensing a temperature of the refrigerant using a sensing bulb (Fig. 1, sensing bulb 18) and communicating a pressure to the bi-flow TXV based on the sensed temperature (Col. 3, lines 16-22, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed) and configured to communicate a pressure to the bi-flow TXV based on the sensed temperature for operating the bi-flow TXV (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle);
balancing the pressure communicated to the bi-flow TXV from the sensing bulb using an equalizer line (Fig. 1, equalizer line 20) having a first end in fluid communication with the bi-flow TXV and a second end in fluid communication with the compressor suction line downstream of the accumulator (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle) and configured to balance the pressure communicated to the bi-flow TXV from the sensing bulb to operate the TXV (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle); and
controlling, using the sensing bulb and the equalizer line, the bi-flow TXV such that the superheat of the refrigerant leaving the evaporator is controlled while maintaining a superheat of the refrigerant entering the compressor (Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports; Col. 3, lines 60-67, The power head of expansion valve 8 is connected to the sensing bulb 18 by means of capillary tube 21. Sensing bulb 18 senses the temperature of the vapor in suction line 19 and equalizer line 20 senses the pressure in line 19 if superheat is high 6° - 7° F. the expansion valve 8 opens further, if the superheat is low 3° -5° F. the valve 8 will further close to restore superheat to a normal 5°-6° F).
However, Hart as modified does not disclose sensing a temperature of the refrigerant entering the accumulator using the sensing bulb.
Chen teaches sensing a temperature of the refrigerant entering the accumulator using the sensing bulb (Fig. 1 of Chen depicts sensing bulb 48 to be disposed upstream of the accumulator 16).
Hart fails to teach sensing a temperature of the refrigerant entering the accumulator using the sensing bulb, however Chen teaches that it is a known method in the art of heat pumps to include sensing a temperature of the refrigerant entering the accumulator using the sensing bulb. This is strong evidence that modifying Hart as claimed would produce predictable results (i.e. operation control based on real-time sensor data to improve overall system efficiencies). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Hart by Chen and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of operation control based on real-time sensor data to improve overall system efficiencies.
Regarding claim 19, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above), wherein the HVAC system is a variable refrigerant flow heat pump system (Hart, Col. 12, lines 12-15, A variable speed compressor may be used or two compressors using a common or connected crankcase may be used to accomplish the 2: 1 ratio in compressor displacement).
Regarding claim 23, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above), further comprising configuring the bi-flow TXV to store refrigerant in the accumulator if there is a refrigerant charge imbalance in the refrigerant circuit (Hart, Col. 3, lines 9-16, Vapor and oil from line 14 enter the reversing valve 3 and are directed to line 15 which is connected to the top of accumulator 16. In accumulator 16 any liquid refrigerant and oil -are trapped and prevented from returning directly to the compressor. An orifice disposed at the bottom of the U tube 17 in the accumulator 16 slowly dispenses any oil or liquid refrigerant back to the compressor in a non-slugging manner; Further, the bi-directional balanced expansion valve 8 of Hart has the same structure as the claimed bi-flow thermostatic expansion valve and is capable of functioning in the manner claimed).
Regarding claim 27, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above), wherein the TXV comprises a balanced port design (Hart, Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports).
Regarding claim 31, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), wherein the sensing bulb is upstream of the accumulator (Fig. 1 of Chen depicts sensing bulb 48 to be disposed upstream of the accumulator 16). Further, the limitations of claim 31 are the result of the modification of references used in the rejection of claim 1 above.
Regarding claim 32, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above), wherein the sensing bulb is upstream of the accumulator (Fig. 1 of Chen depicts sensing bulb 48 to be disposed upstream of the accumulator 16). Further, the limitations of claim 32 are the result of the modification of references used in the rejection of claim 17 above.
Regarding claim 33, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above), wherein the sensing bulb is upstream of the accumulator (Fig. 1 of Chen depicts sensing bulb 48 to be disposed upstream of the accumulator 16) and the second end of the equalizer line is located downstream of the accumulator and upstream of the compressor (Fig. 1 of Hart depicts equalizer line 20 to be in fluid communication with the suction line 19 downstream of the accumulator 19 and upstream of the compressor 1). Further, the limitations of claim 33 are the result of the modification of references used in the rejection of claim 1 above.
Regarding claim 34, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above), wherein the sensing bulb is upstream of the accumulator (Fig. 1 of Chen depicts sensing bulb 48 to be disposed upstream of the accumulator 16) and the second end of the equalizer line is located downstream of the accumulator and upstream of the compressor (Fig. 1 of Hart depicts equalizer line 20 to be in fluid communication with the suction line 19 downstream of the accumulator 19 and upstream of the compressor 1). Further, the limitations of claim 33 are the result of the modification of references used in the rejection of claim 1 above.
Claims 2 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Hart as modified by Chen as applied to claims 1 and 17 above, respectively, and further in view of Alford (US Patent No. 6,644,049), hereinafter Alford.
Regarding claim 2, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Hart as modified does not disclose wherein the HVAC system is a rooftop HVAC system.
Alford teaches wherein the HVAC system is a rooftop HVAC system (Fig. 1, rooftop 14, Col. 3, lines 23-26, the space conditioning system 10 is shown, by way of example, as a so-called "rooftop" system having a generally rectangular box-like enclosure or cabinet 12 adapted to be mounted on a generally horizontal surface or rooftop 14).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the HVAC system of Hart as modified to be a rooftop system as taught by Alford. One of ordinary skill in the art would have been motivated to make this modification to take advantage of air flow to achieve performance improvements.
Regarding claim 18, Hart as modified discloses the method of claim 18 (see the combination of references used in the rejection of claim 17 above).
However, Hart as modified does not disclose wherein the HVAC system is a rooftop HVAC system.
Alford teaches wherein the HVAC system is a rooftop HVAC system (Fig. 1, rooftop 14, Col. 3, lines 23-26, the space conditioning system 10 is shown, by way of example, as a so-called "rooftop" system having a generally rectangular box-like enclosure or cabinet 12 adapted to be mounted on a generally horizontal surface or rooftop 14).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the HVAC system of the method of Hart as modified to be a rooftop system as taught by Alford. One of ordinary skill in the art would have been motivated to make this modification to take advantage of air flow to achieve performance improvements.
Claims 4 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Hart as modified by Chen as applied to claims 1 and 17 above, respectively, and further in view of Dostal (US Patent No. 9,052,125), hereinafter Dostal.
Regarding claim 4, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Hart as modified does not disclose further comprising a filter drier located in the refrigerant circuit located on either side of the bi-flow expansion valve.
Dostal teaches further comprising a filter drier (Fig. 1. filter/drier 130) located in the refrigerant circuit located on either side of the bi-flow expansion valve (Fig. 1 of Dostal depicts the filter/drier 130 on one side of first metering device 132).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the HVAC system of Hart as modified to include a filter drier as taught by Dostal. One of ordinary skill in the art would have been motivated to make this modification to protect the system from pollution, such as dirt and foreign matter from entering the circuit or cycle lines (Dostal, Col. 3, lines 63-65).
Regarding claim 20, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above).
However, Hart as modified does not disclose further comprising filtering and drying the refrigerant in the refrigerant circuit using a filter drier located on either side of the bi-flow expansion device.
Dostal teaches further comprising filtering and drying the refrigerant in the refrigerant circuit using a filter drier (Fig. 1. filter/drier 130) located on either side of the bi-flow expansion device (Fig. 1 of Dostal depicts the filter/drier 130 on one side of first metering device 132).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the method of Hart as modified to include a filter drier as taught by Dostal. One of ordinary skill in the art would have been motivated to make this modification to protect the system from pollution, such as dirt and foreign matter from entering the circuit or cycle lines (Dostal, Col. 3, lines 63-65).
Claims 11 and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Hart as modified by Chen as applied to claims 1 and 17 above, respectively, and further in view of Wiggs (US Patent No. 8,776,543), hereinafter Wiggs.
Regarding claim 11, Hart as modified discloses the HVAC system of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Hart as modified does not disclose wherein the bi-flow TXV comprises a bleed port.
Wiggs teaches wherein the bi-flow TXV comprises a bleed port (Col. 10, lines 12-14, A TXV 7 can also be constructed with an internal bleed port that permits refrigerant to continuously flow through the TXV 7).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the bi-flow TXV of Hart as modified to include a bleed port as taught by Wiggs. One of ordinary skill in the art would have been motivated to make this modification because This arrangement ensures adequate refrigerant flow and eliminates interior heat exchanger frosting when the system is switched from the heating mode to the cooling mode when the sub-surface ground temperatures is at or below approximately 50 degrees F (Wiggs, Col. 4-5, lines 67 and 1-4).
Regarding claim 26, Hart as modified discloses the method of claim 17 (see the combination of references used in the rejection of claim 17 above).
However, Hart as modified does not disclose wherein the bi-flow TXV comprises a bleed port.
Wiggs teaches wherein the bi-flow TXV comprises a bleed port (Col. 10, lines 12-14, A TXV 7 can also be constructed with an internal bleed port that permits refrigerant to continuously flow through the TXV 7).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the bi-flow TXV of Hart as modified to include a bleed port as taught by Wiggs. One of ordinary skill in the art would have been motivated to make this modification because This arrangement ensures adequate refrigerant flow and eliminates interior heat exchanger frosting when the system is switched from the heating mode to the cooling mode when the sub-surface ground temperatures is at or below approximately 50 degrees F (Wiggs, Col. 4-5, lines 67 and 1-4).
Response to Arguments
Applicant's arguments filed February 05th, 2026 have been fully considered but they are not persuasive.
Applicant argues on Pg. 8 of the response, “Further, Hart does not teach using the sensing bulb and the equalizer line to control the expansion valve 8 such that at least some of any liquid refrigerant is separated from vaporized refrigerant in the accumulator to lower the superheat of the refrigerant leaving the evaporator while maintaining a superheat of the refrigerant entering the compressor compared to not separating the refrigerant as claimed.” However, this argument is not persuasive as Hart explicitly discloses using the sensing bulb 18 and the equalizer line 20 to maintain superheat temperatures at the compressor within a desired range, this control of superheat vapor temperatures at the compressor is done by altering the expansion degree of the bi-directional balanced expansion valve 8 upstream of the indoor coil 5 which aids in the control of superheat temperatures leaving the indoor coil 5 (Hart, Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports; Col. 3, lines 60-67, The power head of expansion valve 8 is connected to the sensing bulb 18 by means of capillary tube 21. Sensing bulb 18 senses the temperature of the vapor in suction line 19 and equalizer line 20 senses the pressure in line 19 if superheat is high 6° - 7° F. the expansion valve 8 opens further, if the superheat is low 3° -5° F. the valve 8 will further close to restore superheat to a normal 5°-6° F). Further, the function of an accumulator in a heat pump system to separate liquid and vapor phases of a refrigerant, and additional oil, allows for the heat pump system to operate at lower superheat temperatures in comparison to heat pump systems that do not have accumulators and is simply a function of the structure of an accumulator in a heat pump system (Hart, Col. 3, lines 9-16, Vapor and oil from line 14 enter the reversing valve 3 and are directed to line 15 which is connected to the top of accumulator 16. In accumulator 16 any liquid refrigerant and oil -are trapped and prevented from returning directly to the compressor. An orifice disposed at the bottom of the U tube 17 in the accumulator 16 slowly dispenses any oil or liquid refrigerant back to the compressor in a non-slugging manner). See the rejections of claims 1 and 17 above.
Applicant argues on Pg. 8 of the response, “Additionally, Chen fails to remedy the deficiencies of Hart. Chen discloses a remote sensing bulb 48 disposed in heat transferable contact with a refrigerant piping section between an accumulator and a reversing valve. In the configurations shown and described, the sensing bulb 48 is placed on the evaporator outlet side of the suction path and not at the point where refrigerant enters the accumulator. Thus, the sensing bulb 48 is not positioned to and does not sense temperature of the refrigerant entering the accumulator as claimed. In short, while Chen moves the bulb away from Hart's compressor-adjacent placement, it does not teach sensing the temperature "entering the accumulator."” However, this argument is not persuasive as the remote sensing bulb 48’s placement on the evaporator outlet side of the suction path is the entrance for two phase refrigerant to enter the accumulator 16 of Chen. The teachings of Chen explicitly show it is known in the art to have a sensing bulb that is connected to a TXV on the upstream side of an accumulator of a heat pump system for sensing temperatures of a refrigerant entering the accumulator (Chen, Fig. 1). See the rejections of claims 1 and 17 above.
Applicant argues on Pg. 8 of the response, “Further, Chen teaches artificially heating remote sensing bulb 48 to mitigate frost. Chen does not teach using the sensing bulb and the equalizer line to control the expansion valve 22 such that at least some of any liquid refrigerant is separated from vaporized refrigerant in the accumulator to lower the superheat of the refrigerant leaving the evaporator while maintaining a superheat of the refrigerant entering the compressor compared to not separating the refrigerant as claimed.” However, this argument is not persuasive as Chen is simply relied upon to show it is known in the art to have a sensing bulb that is connected to a TXV on the upstream side of an accumulator of a heat pump system for sensing temperatures of a refrigerant entering the accumulator (Chen, Fig. 1). The function of using a sensing bulb and an equalizer line to control the expansion valve such that at least some of any liquid refrigerant is separated from vaporized refrigerant in the accumulator to lower the superheat of the refrigerant leaving the evaporator while maintaining a superheat of the refrigerant entering the compressor compared to not separating the refrigerant is already disclosed by Hart (Hart, Col. 3, lines 16-25, The power head of the expansion valve 8 is connected to the sensing bulb 18 by means of a capillary tube 21. Sensing bulb 18 is clamped to suction line 19 for sensing temperature of superheat of the vapor entering the compressor and 20 equalizer line 20 where pressure in suction line 19 is sensed. High superheat (6°-7° F.) opens the valve to keep the optimum amount of refrigerant flowing to the earth coils 11,12 and 13. This completes the cooling cycle; Col. 3, lines 47-49, The liquid flows through line 9 to expansion valve 8 which is a bi-directional valve with pressure balanced ports; Col. 3, lines 60-67, The power head of expansion valve 8 is connected to the sensing bulb 18 by means of capillary tube 21. Sensing bulb 18 senses the temperature of the vapor in suction line 19 and equalizer line 20 senses the pressure in line 19 if superheat is high 6° - 7° F. the expansion valve 8 opens further, if the superheat is low 3° -5° F. the valve 8 will further close to restore superheat to a normal 5°-6° F). See the rejections of claims 1 and 17 above.
Applicant's arguments on Pg. 8-9 of the response filed February 05th, 2026 which recite, “Further, there is no motivation to modify Hart with Chen as proposed. As mentioned above, Hart specifically positions the sensing bulb 18 between the accumulator 16 and the compressor 1 to sense the temperature of superheat of the vapor entering the compressor 1 to keep the optimum amount of refrigerant flowing to the earth coils 11, 12, and 13. Moving the sensing bulb upstream of the accumulator 16 would no longer be sensing the temperature of the flow into the compressor. In this position, the sensing bulb 18 would now measure accumulator entrance conditions (two-phase rich / higher variability), before the accumulator has separated residual liquid. This shifts the control objective from "control compressor-inlet superheat" to something closer to "control evaporator-exit superheat," which would risk inefficiency and damage to the compressor 1. Doing so would thus materially change the operation of Hart and render Hart ineffective for managing the superheat of the flow into the compressor 1. Thus, there is no motivation to modify Hart by moving the sensing bulb upstream of the accumulator 16” are acknowledged by the Examiner. In light of these arguments, the 35 U.S.C rejections of claims 1 and 7 have been amended. See the rejections of claims 1 and 17 above.
The rejections of independent claims 1 and 17 are maintained. The rejections of dependent claims 2-4, 7-9, 11-12, 18-20, 23, 26-27, and 31-34 are also maintained for at least the reasons described herein.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Lame et al. (US Patent No. 5,016,447) discloses a similar HVAC system with a sensing bulb positioned to sense the temperature of refrigerant entering an accumulator.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DEVON T MOORE whose telephone number is 571-272-6555. The examiner can normally be reached M-F, 7:30-5.
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/DEVON MOORE/Examiner, Art Unit 3763 February 24th, 2026
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763