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 .
Response to Amendment
The amendment filed 01/27/2026 presents claims 1, 5, and 11 as amended and claims 16-20 as added. Therefore, claims 1-20 are pending.
The amendment to claim 11 is sufficient in overcoming the previously indicated objection to the same.
The amendment to claim 5 is sufficient in overcoming the previously indicated rejection under 35 USC 112 (b) to the same.
The amendment to claim 1 is sufficient in overcoming the previously indicated rejection under 35 USC 103 to the same.
Further grounds of objection and rejection, necessitated by the amendment, are presented herein.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 01/13/2026 was filed after the mailing date of the Office action on 10/27/2025. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Response to Arguments
Applicant’s arguments with respect to claim(s) 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Claim Objections
Claim 7 is objected to under 37 CFR 1.75 as being a substantial duplicate of claim 16. In this case, claim 16 recites the subject matter of claim 7 including the limitations of claim 1 and intervening claim 6. When two claims in an application are duplicates or else are so close in content that they both cover the same thing, despite a slight difference in wording, it is proper after allowing one claim to object to the other as being a substantial duplicate of the allowed claim. See MPEP § 608.01(m).
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.
Claim(s) 1-6 and 10-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Callahan et al. (US20060291527) in view of Hwang et al. (US 20200260534), and in further view of Etscheid et al. (US2011/0248017).
Regarding claim 1, Callahan teaches a liquid heater (Title; “Direct Electric Resistance Liquid Heater”) (see also paragraph 0001) comprising:
a chamber for receiving a liquid (liquid heating chamber 1; Fig. 1);
pairs of electrodes (electrode arrays 4) located within the chamber (1) for applying electric current (AC power 7; para. 0031) to the liquid;
input terminals (terminals connecting the electrodes to the AC power supply 7) for connection to a power supply (electrodes 4 are connected to AC power 7 via connections 5 and switch matrix 6);
a plurality of switches (switch matrix 6 including plurality of switches 8; Fig. 2) (para. 0033 discloses the switches being triacs) for connecting the pairs of electrodes (4) to the input terminals (the switches enable electrical connection between the AC power 7 and electrodes 4 to allow current to flow); and
a control unit (10; Fig. 5) for controlling the switches (Abstract; a “controller controls the switches based upon data received” from a temperature/current sensor. The controller can incrementally increase or decrease the current applied to the liquid due to the number of switches and spacing between electrodes.) (see also Paragraphs 0034-0035), wherein:
the switches have a plurality of different states for selectively connecting pairs of electrodes to the input terminals in one of a plurality of electrode configurations (para. 0036; “a large number of possible combinations of switch positions or switch configurations, i.e., 2 raised to the power of the number of switches.”, the electrodes having a different total electrical resistance in each electrode configuration. See also Figures 3-4 showing current level relative to switch configuration and Table 1 showing switch configuration and power level with 0 being open and 1 being closed. Paragraph 0063 discloses that at power level 0 all the switches were open and no power was applied. Similarly, at power level 65 all the switches were closed and maximum power was applied.).
Callahan teaches substantially the claimed invention including switching between a first electrode configuration having a first total electrical resistance, and a second electrode configuration having a second lower total electrical resistance (For example, the total resistance when a subset of the switches are open (with the remaining closed) is lower than a configuration when all the switches are closed). Callahan also teaches that it is customary, to reduce electromagnetic or radio frequency interference, for the switches to be operatively closed at the zero crossing of the power supply waveform (para. 0065).
Callahan is silent on the control unit controlling the switches such that:
switching between the electrode configurations occurs in response to zero-crossings in a voltage of the power supply; and/or
(ii) the electrodes of the first electrode configuration are energised with a voltage having a first duty, and the electrodes of the second electrode configuration are energised with a voltage having a second higher duty.
In other words, Callahan does not explicitly disclose how the zero crossing relates to the control of the switches.
Hwang relates to a heating module (para. 0002, Fig. 3) and is concerned with controlling current flow to a plurality of heaters (160) via a plurality of switches (triacs 182). Hwang teaches a controller (210) being operatively coupled to a zero crossing switching circuit (184) which controls “a switching time point of the switching devices 182 to prevent the switching devices 182 from being damaged by sparks or electrical discharges” (para. 0032; “whenever the phase of the electric power becomes 0, the zero cross switching circuit 184 may turn the switching devices 182 on or off, based on a control signal transmitted from the current control unit 216.”). Accordingly, Hwang teaches the controller (210) switching between electrode configurations occurs in response to zero-crossings in a voltage of the power supply.
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan with Hwang, by adding to the controller of Callahan, already controlling the switching of the switches and, as a result, the electrode configuration, with the zero cross switching circuit of Hwang, for in doing so would provide a means for the controller to ascertain when the phase of electric power becomes 0 (i.e., zero crossing) which would allow for the switches to be operated without being damaged by sparks or electrical discharges.
The above combination teaches the claimed invention including the control unit controlling the switches, but is silent on the electrodes of the first electrode configuration are energised with a voltage having a first duty, and the electrodes of the second electrode configuration are energised with a voltage having a second higher duty.
Etscheid relates to a fluid heating system in which multiple heating elements are selectively operated (Abstract and para. 0002-0003; Fig. 4, R1, R2, R3 selectively operated via respective control element T1, T2, and T3).
Etscheid teaches a control unit (6) controlling the control elements (T1-T3; para. 0027) such that the heating elements (R1-R3) of a first configuration are energised with a voltage having a first duty, and the heating elements (R1-R3) of a second configuration are energised with a voltage having a second higher duty (para. 0027; controlling each T1-T3 so that the power of each heating element is independently regulated) (para. 0010; each heating element is operated by a separate operating voltage) (para. 0031; voltage can be between 0 and 100%. Para. 0034; voltage pulses including full voltage and no voltage states) (Fig. 9 and para. 0053; “the heating elements are preferably driven at a time offset with respect to the PWM control, such that their PWM signals (cf. FIG. 9 the voltage pulses U.sub.1, U.sub.2 and U.sub.3) do not, or only partly overlap in time. For example, it is possible to drive the heating elements R.sub.1 and R.sub.3 with operating voltages U.sub.1 and U.sub.3 during the pause times of the control of the heating element R.sub.2 and/or of its operating voltage U.sub.2, wherein in contrast to the illustration in FIG. 9, the voltage pulses U.sub.1 and U.sub.3 of the parts diagrams b) and c) can be offset in time to one another within the pause of U.sub.2 according to diagram a) (see the voltage pulse for U.sub.1 shown hatched and with dashed lines in diagram b)). Due to this measure, the maximum total current of the heating system is advantageously kept small.”).
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan, as modified by Hwang, with Etscheid, by adding to the controller of Callahan, already controlling the switching of the switches and, as a result, the electrode configuration, with the first electrode configuration being energised with a voltage having a first duty, and the electrodes of the second electrode configuration being energised with a voltage having a second higher duty of Etscheid, for in doing so would further improve the tailing or the heating profile, by selectively actuating individual heating elements, while keeping the maximum total current of the heating system small.
Regarding claim 2, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein the liquid heater comprises at least six electrode configurations (see Table 1 of Callahan, each power level shows a different electrode configuration).
Regarding claim 3, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein each pair of electrodes has a different electrical resistance (the resistance of each electrode pair relates to the applied current via Ohm’s Law. By varying the current applied via the switches, the resistance also changes).
Regarding claim 4, the primary combination teaches substantially the claimed invention, as applied in claim 1.
Callahan teaches wherein the electrical resistances of the pairs of electrodes have a maximum of Rmax and a minimum of Rmin (the electrical resistances of the electrodes inherently has a min and max resistance of some value), but is silent on where Rmax/Rmin is at least 10.
The instant specification states that by having the Rmax/Rmin at least 10 allows for “a relatively wide dynamic range” (para. 0070).
Callahan discloses a rather large number of configurations allowing for a wide range of currents. Specifically, Callahan discloses a 250:1 range of currents being achieved. Here, the current applied is inversely proportional to the resistance via Ohm’s Law. Callahan, therefore, naturally suggests a range of resistances depending on the selected configuration. Accordingly, providing a specific range of minimum and maximum resistances amounts to routine optimization, where the instant specification lacks disclosure for any criticality.
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan with Hwang, by replacing the ratio of the minimum and maximum resistance of Callahan, being inherently of some value, to be at least 10, since the ration of minimum and maximum resistance is interpreted to be a result effective variable that would be optimized in order to achieve a recognized result. In this case the recognized result would be achieving a particular current and, as such, a desired heating profile. A person of ordinary skill in the art would recognize that the resistance is inversely proportional to current and that increasing current causes a decrease in resistance (for constant voltage). Varying the ratio of resistances would allow for varying currents to be applied and, ultimately, varied heating profiles to be achieved. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." See MPEP 2144.05-ll-A and MPEP 2144.05-ll-B.
Regarding claim 5, the primary combination teaches substantially the claimed invention, as applied in claim 1.
Callahan teaches wherein the electrical resistances of the pairs of electrodes have a maximum of Rmax and a minimum of Rmin (the electrical resistances of the electrodes inherently has a min and max resistance of some value). Callahan also teaches a difference in the total electrical resistances of any two electrode configurations having a maximum of Rmaxdiff (interpreted as a difference in total electrical resistances between any of the electrode configurations). Callahan is silent on where RTmax/RTmin is at least 20 and Rmaxdiff/(RTmax−RTmin) is no greater than 35%.
The instant specification states that such ranges allow for “relatively good balance” and “resolution” (para. 0009).
Callahan discloses a rather large number of configurations allowing for a wide range of currents. Specifically, Callahan discloses a 250:1 range of currents being achieved. Here, the current applied is inversely proportional to the resistance via Ohm’s Law. Callahan, therefore, naturally suggests a range of resistances depending on the selected configuration. Accordingly, providing a specific range of minimum and maximum resistances amounts to routine optimization, where the instant specification lacks disclosure for any criticality.
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan with Hwang, by replacing the ratio of the minimum and maximum total resistances (RTmax/RTmin and Rmaxxdiff/(RTmax-RTmin) of Callahan, being inherently of some value, to be at least 20 and 35%, respectively, since the ratio of minimum and maximum resistance is interpreted to be a result effective variable that would be optimized in order to achieve a recognized result. In this case the recognized result would be achieving a particular current and, as such, a desired heating profile. A person of ordinary skill in the art would recognize that the resistance is inversely proportional to current and that increasing current causes a decrease in resistance (for constant voltage). Varying the ratio of resistances would allow for varying currents to be applied and, ultimately, varied heating profiles to be achieved. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." See MPEP 2144.05-ll-A and MPEP 2144.05-ll-B.
Regarding claim 6, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein the control unit controls the switches such that the electrodes are energised with an alternating voltage within each configuration (Callahan; from AC power source 7).
Regarding claim 10, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein [Callahan] the liquid heater comprises a temperature sensor (12) for sensing a temperature of the liquid, and the control unit controls the switches so as to select an electrode configuration based on the temperature of the liquid and a temperature setpoint (para. 0059).
Regarding claim 11, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein [Callahan] the liquid heater comprises a temperature sensor (12) for sensing a temperature of the liquid, and the control unit controls the switches such that the electrodes are energised with a voltage having a duty defined by the temperature of the liquid and a temperature setpoint (para. 0059).
Regarding claim 12, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein [Callahan] the wherein the control unit controls the switches such that the electrodes are energised with a voltage having a variable duty no less than 70% (para. 0063; power level 65 all switches are closed and maximum power is applied for heating fluid. This implies a duty cycle, or on time, of greater than 70%.) (See also, para. 0065).
Regarding claim 13, the primary combination teaches the claimed invention, as applied in claim 1, and further teaches wherein [Callahan] the power supply supplies an alternating voltage (AC source 7), and the switches are bi-directional switches (Callahan discloses using triac switches. Those of ordinary skill in the art would understand that triacs are bidirectional).
Claim(s) 8 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Callahan et al. (US20060291527) in view of Hwang et al. (US 20200260534), Etscheid et al. (US2011/0248017), and in further view of Schulz (US20130022340)
Regarding claim 8, the primary combination teaches the claimed invention, as applied in claim 1, including wherein the power supply supplies an alternating voltage (Callahan, AC power supply 7). The combination is silent on the control unit controls the switches such that, within at least one setting, the electrodes are energised only during each Nth half-cycle of the alternating voltage, where N is at least 2.
Schulz relates to liquid heating (para. 0002-0003) and is concerned with controlling the temperature of the liquid (para. 0004). Schulz teaches controlling a triac switch (24) to energize the heater only during each Nth half-cycle of the alternating voltage, where N is at least 2 (para. 0052; controller 22 is connected to an AC voltage network supplying current to the heater and controls switch 24 such that the heater is switched on for a half-wave and switched off during the subsequent half-wave-para. 0052 [As such, the heater is energized every other half cycle]).
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan as modified by Hwang and Etscheid, with Schulz by adding to the controlling of the switching elements of Callahan, with the energizing only during each Nth half-cycle of the alternating voltage, where N is at least 2 as taught by Schulz, for in doing so would provide further prevent radio interference and large increases in current (Schulz; para. 0052).
Regarding claim 9, the primary combination teaches the claimed invention, as applied in claim 1, including wherein the power supply supplies an alternating voltage (Callahan, AC power supply 7). The combination is silent on the control unit controls the switches such that, within at least one setting, the electrodes are energised during one or more portions only of each half-cycle of the alternating voltage.
Schulz relates to liquid heating (para. 0002-0003) and is concerned with controlling the temperature of the liquid (para. 0004). Schulz teaches controlling a triac switch (24) to energize the heater during one or more portions only of each half-cycle of the alternating voltage (para. 0052; controller 22 is connected to an AC voltage network supplying current to the heater and controls switch 24 such that the heater is switched on for a half-wave and switched off during the subsequent half-wave-para. 0052 [As such, the heater is energized every other half cycle]).
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan as modified by Hwang and Etscheid, with Schulz by adding to the controlling of the switching elements of Callahan, with the energizing during one or more portions only of each half-cycle of the alternating voltage as taught by Schulz, for in doing so would provide further prevent radio interference and large increases in current (Schulz; para. 0052).
Claim(s) 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Callahan et al. (US20060291527) in view of Hwang et al. (US 20200260534), Etscheid et al. (US2011/0248017), and in further view of Dietschi (WO2018184914; Applicant Submitted Prior Art).
Regarding claims 14-15, the primary combination teaches substantially the claimed invention, as applied to claim 1, including the power supply supplying an alternating voltage having a first frequency no greater than 60 Hz (Callahan, 50-60 Hz power supply-para. 0065). Callahan is silent on the control unit controls the switches such that the electrodes are energised with an alternating voltage having a second higher frequency (claim 14), wherein the second frequency is no less than 150 kHz (claim 15).
Dietschi relates to a system for ohmic heating of a fluid in which a plurality of electrodes are disposed within a chamber (Abstract; Fig. 2A/B) and teaches using a frequency inverter (10) coupled to a power supply (8). Dietschi teaches that the power supply (8) has a frequency from 50-60 Hz [corresponding to that of Callahan] and that the inverter is used to produce a higher frequency of over 200 kHz (page 4, lines 23-35 and page 5, lines 1-2).
Therefore, it would have been obvious to someone with ordinary skill in the art at the time the invention was filed to modify Callahan as modified by Hwang and Etscheid, with Dietschi by adding to the power supply and controller of Callahan, with the inverter of Dietschi, for in doing so would provide a higher frequency to the system which would allow for the number of electrodes to be reduced in order to cover a larger working range (as stated by Dietschi).
Allowable Subject Matter
Claim 7 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding claim 7, the primary combination teaches substantially the claimed invention, as applied to claim 6, including wherein the switches have a first state in which the electrodes are energised with a positive voltage and a second state in which the electrodes are energised with a negative voltage (Callahan, the AC power supply 7 applies positive and negative voltages).
Callahan is silent on the control unit switches the switches between the first state and the second state at a switching frequency of at least 300 kHz.
Spitthover (US20190223258) relates to a method for operating a heating element and teaches operating a heating element at a switching frequency from 2-40 kHz, preferably 10-30 kHz, and preferably 20 kHz (para. 0020).
Nielsen (US20160252271) relates to a system of heating a liquid via switching of AC voltage source (Abstract) and teaches a switch frequency of approximately 30 kHz (para. 0028).
Stewart (US20160218635) relates to a system for regulating AC voltage (para. 0003) and teaches operating semiconductor switch at 25 kHz (para. 0025).
Klyosov (US20160043626) relates to a power supply source for a heating system (Abstract) and teaches using an electronic switch having an operating frequency of 20-100 kHz (para. 0027).
The prior art of record fails to teach, suggest, or otherwise disclose a control unit operating a plurality of switches between a first and second state at a switching frequency of at least 300 kHz, as required in claim 7, as such limitation pertains to, or otherwise depends from, the remaining limitations in the claim. Further, there is no evidence of record to suggest that one of ordinary skill in the art would have been motivated, or have considered it obvious, to modify the prior art of record to employ a switching frequency of at least 300 kHz.
Claims 16-20 are allowed. Independent claim 16 incorporates the subject matter of claim 7 into independent format and includes all limitations of claim 1 and intervening claim 6. For the same reasons detailed above, claim 16 recites allowable subject matter. Claims 17-20, depending from claim 16, are similarly allowable.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JUSTIN C DODSON whose telephone number is (571)270-0529. The examiner can normally be reached Mon.-Fri. 1:00-9:00 PM (ET).
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/JUSTIN C DODSON/ Primary Examiner, Art Unit 3761