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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 08/07/2026 has been entered.
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.
Claim(s) 1, 3-10 and 13-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Callahan et al. (US 20190271487) in view of Callahan et al. (US 2006/0291527) and Dietschi (WO 2018/184914).
Regarding claim 1, Callahan et al. (‘487) discloses “a liquid heater” (abstract and [0002], i.e., An ohmic fluid heater can be used to heat an electrically conductive fluid as, for example, potable water.) comprising:
“a chamber” (10 has an interior space or a chamber) for receiving a liquid;
“a plurality of pairs of electrodes” (figs.1 and 3, 14(0), 14(1), 14 (3) and 14 (4). Examiner interprets that first pair can be 14(0), 14(1) and a second pair can be 14 (3) and 14 (4)) “longitudinally aligned with one another and located within the chamber” (fig.1 shows the pairs of electrodes are aligned with one another and located within the chamber) “for applying electric current to the liquid” ([0002], i.e., An ohmic fluid heater can be used to heat an electrically conductive fluid … For example, where an ohmic heater is operated using normal AC utility power such as that obtainable from a household electric plug, at least one of the electrodes is connected to one pole carrying an alternating potential, whereas at least one other electrode is connected to the opposite pole carrying a neutral or ground pole. Electricity passes between the electrodes through the fluid at least one space between the electrodes, and electrical energy is converted to heat by the electrical resistance of the fluid), with “the electrodes within each of the plurality of pairs being electrically coupled to one another” (fig.3 shows the electrodes of the plurality of pairs 14 being electrically coupled to one another via switches);
“input terminals for connection to a power supply” (annotated fig.3);
“a plurality of switches” (48) for connecting “the pairs of electrodes” (figs.1 and 3, 14(0), 14(1), 14 (3) and 14 (4).) to “the input terminals” (annotated fig.3); and
“a control unit” (52) for controlling “the switches” (48),
wherein:
Callahan et al. (‘527) teaches wherein: “the switches are bi-directional” (para.0033, Triacs. Examiner noted that triacs is a type of bi-directional switches);
“the power supply supplies an alternating voltage having a frequency no greater than 60 Hz” ([0065] The algorithm was executed once per every cycle of the AC power supply 7 and thus caused the maximum rate of change of the load to the power supply to be nominally 10% per cycle in this example of the invention. It took 65 cycles to effect a change of current from zero current to maximum current (over 1 second for a 50 Hz or 60 Hz power supply)).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Callahan et al. (‘487) with Callahan et al. (‘527), by modifying Callahan et al. (‘487)’s power supply frequency with Callahan et al. (‘527)’s power supply frequency, to have less electrical stress on equipment, and reduced noise and glow effects.
Dietschi teaches “the control unit controls the switches such that the electrodes are energised with an alternating voltage having a frequency no less than 150 kHz” (Claim 13, i.e., that each electronic switch (2) of the switching arrangement is coupled to at least one control unit (3). Claim 23, i.e., the polarity of the voltage is controlled such that a pulse frequency of up to 3 MHz is obtained.). It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Callahan et al. with Dietschi, by modifying Callahan et al.’s frequency for the electrodes according to Dietschi’s the electrodes are energised with an alternating voltage having a frequency no less than 150 kHz, to provide intense, rapid and highly localized heat for faster heating.
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Regarding claim 3, modified Callahan et al. (‘487) discloses “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, and the electrodes have a different total electrical resistance in each electrode configuration” (Callahan et al. (‘527), para.0036, i.e., there are a large number of possible combinations of switch positions or switch configurations, i.e., 2 raised to the power of the number of switches. Figs.3-4 shows the current level in relation to the switch configuration and Table 1 showing switch configuration and power level with 0 being open and 1 being closed. Para.0063 discuss about the power level 0 all the switches were open and no power was applied. Similarity, at power level 65 all the switches were closed and maximum power was applied).
Regarding claim 4, modified Callahan et al. (‘487) discloses “the liquid heater comprises at least six electrode configurations” (Callahan et al. (‘487), embodiment fig.12 shows the fluid heater can be modify to have at least six electrodes 114 configuration).
Regarding claim 5, modified Callahan et al. (‘487) discloses “each pair of electrodes has a different electrical resistance” (Callahan et al. (‘527), abstract, i.e., the electrodes are each connected to a power supply by one or more switches … the controller can incrementally increase or decrease the current applied to the liquid to be heated. Examiner noted that 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 6, modified Callahan et al. (‘487) discloses the electrical resistance of the pairs of electrodes have a maximum of Rmax and a minimum of Rmin (Callahan et al. (‘527), 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 publication application states “[0010] The electrical resistances of the pairs of electrodes may have a maximum of Rmax and a minimum of Rmin, where Rmax/Rmin is at least 10. As a result, a relatively wide dynamic range in the total electrical resistance of the various electrode configurations may be achieved”.
Callahan (‘527) discloses a larger number of configuration allowing for a wide range of currents. Specifically, Callahan discloses a 250:1 (para.0037) range of currents being achieved. Here, the current applied is inversely proportional to the resistance via Ohm’s Law. Callahan, Therefore, it 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. It would have been obvious to someone with ordinary skill in the art at the time the invention wad filed to further modify Callahan (‘487) with Dietschi, by replacing the ratio of the minimum and maximum resistance of Callahan (‘487), being inherently of some value, to be at least 10, 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. MPEP 2144.05, II, A and MPEP 2144.05, II, B.
Regarding claim 7, modified Callahan et al. (‘487) teaches wherein “the electrical resistances of the pairs of electrodes have a maximum of Rmax and a minimum of Rmin” (Callahan (‘527), the electrical resistances of the electrodes inherently has a min and max resistance of some value). Callahan (‘527) also teaches a difference in the total electrical resistances of any two ranked electrode configurations having a maximum of Rmaxdiff (interpreted as a difference in total electrical resistances between any of the electrode configurations).
Callahan (‘527) is silent on where RTmax/RTmin is at least 20 and Rmaxdiff/(RTmax-RTmin) is no greater than 35%. However, the instant specification states that such ranges allow for "relatively good balance" and "resolution" (para. 0011). Callahan discloses a rather large number of configurations allowing for a wide range of currents. Specifically, Callahan (‘527) discloses a 250:1 (para.0037) range of currents being achieved. Here, the current applied is inversely proportional to the resistance via Ohm's Law. Callahan (‘527), therefore, it 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 (‘527) with Dietschi, by replacing the ratio of the minimum and maximum total resistances (RTmax/RTmin and Rmaxxdiff/RTmax-RTmin) of Callahan (‘527), 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, II, A and MPEP 2144.05, II, B.
Regarding claim 8, modified Callahan et al. (‘487) teaches “the liquid heater comprises a temperature sensor (Callahan (‘527), 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” (Callahan (‘527), para.0059, i.e., a temperature-sensing element 12 is disposed at the end of the heating chamber, prior to outlet 3, and generates a temperature signal 14 indicative of the heated liquid temperature. The heated liquid temperature signal 14 is communicated to controller 10 which responds to it by adjusting the configuration of switch matrix 6 such that the water temperature is maintained as close as possible to a temperature set-point, but which, in any case, does not exceed it. The matrix switch configuration is always set such that current set-point takes priority over the temperature set-point. In other words, regardless of the demand for power to heat the liquid to the temperature set-point, the controller prevents drawing more current from the AC power supply 7 than the current set-point.).
Regarding claim 9, modified Callahan et al. (‘487) teaches the liquid heater comprises a temperature sensor (Callahan (‘527), 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 the temperature setpoint” (Callahan (‘527), para.0059, i.e., a temperature-sensing element 12 is disposed at the end of the heating chamber, prior to outlet 3, and generates a temperature signal 14 indicative of the heated liquid temperature. The heated liquid temperature signal 14 is communicated to controller 10 which responds to it by adjusting the configuration of switch matrix 6 such that the water temperature is maintained as close as possible to a temperature set-point, but which, in any case, does not exceed it. The matrix switch configuration is always set such that current set-point takes priority over the temperature set-point. In other words, regardless of the demand for power to heat the liquid to the temperature set-point, the controller prevents drawing more current from the AC power supply 7 than the current set-point.).
Regarding claim 10, modified Callahan et al. (‘487) teaches “the control unit controls the switches” (Callahan (‘527), control unit 10 controls switches 6) such that “the electrodes are energised with a voltage having a variable duty no less than 70%” (Callahan (‘527), para.0063, i.e., power level 65 all switches are closed and maximum power is applied for heating fluid. This implies that a duty cycle, or on time, of greater than 70%. See also para.0065).
Regarding claim 13, modified Callahan et al. (‘487) teaches “the chamber is configured such that the liquid flows in a single direction between each of the pairs of electrodes in a sequential manner” (Callahan et al. (‘487), the liquid flow in a single direction between each of the pairs of the electrodes. For example between electrodes 14(4) and 14(3) the liquid flow from left to right in a horizontal direction and between electrodes 14(1) and 14(0), the liquid flow in a single direction from right to left).
Regarding claim 14, modified Callahan et al. (‘487) teaches “the chamber has a length” (Callahan et al. (‘487), chamber 10 has a length in horizontal direction) and “the pairs of electrodes are arranged in an upstream-downstream manner along the length” (Callahan et al. (‘487), the pair of electrodes 14(4), 14(3), 14(1) and 14(0) are arranged in an upstream-downstream manner (i.e., with respect to inflow and outflow) along the length ).
Claim(s) 11-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Callahan et al. (US 20190271487) in view of Callahan et al. (US 2006/0291527) and Dietschi (WO 2018/184914) as applied in claims 1, 3-10 and 13-14 above, and further in view of Schulz (US 20130022340).
Regarding claim 11, modified Callahan (‘487) teaches wherein the power supply supplies an alternating voltage (Callahan (‘527), AC power supply 7).
Modified Callahan (‘487) is silent regarding 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 teaches 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, i.e., 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. Examiner noted that, as such, the heater is energized every other half cycle). It would have been obvious to someone with ordinary skill in the art at the time the invention was filed to further modify Callahan as modified by 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 (para.0052) as taught by Schulz.
Regarding claim 12, modified Callahan (‘487) teaches the claimed invention, as
applied in claim 1, including wherein the power supply supplies an alternating voltage
(Callahan, AC power supply 7).
Modified Callahan (‘487) is silent regarding 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 Examiner noted that, 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 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 (para.0052) as taught by Schulz.
Allowable Subject Matter
Claim 2 is allowed.
Response to Arguments
Applicant's arguments filed on 04/24/2026 have been fully considered but they are not persuasive.
Applicant argues “amended claim 1 recites a liquid heater having a chamber for receiving a liquid … none of electrodes 4 are electrically coupled to one another …” on pages 6-8 of remark.
In response, applicant’s remarks have been considered. Examiner agree that the amendment to claims overcome prior rejections. However, examiner has introduced a new reference in current rejection with respect to the amended claim limitations.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JIMMY CHOU whose telephone number is (571)270-7107. The examiner can normally be reached Mon-Friday.
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/JIMMY CHOU/Primary Examiner, Art Unit 3761
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