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 .
Claim Interpretation
Regarding claims 18 and 19. The claims recite, “a low pressure” and “a low velocity”. These limitations are being interpreted such that one of ordinary skill in the art would have been reasonably apprised of the scope of the invention because the specification provides a standard for ascertaining the requisite degree, as described in Applicant’s PGPUB para. 18, which states, “Preferably, the reduced pressure exceeds the pressure of the melting chamber atmosphere only as needed for the argon streams to flow through the passages 73 and penetrate the chamber volume beside the downstream ports 91. The increasing flow areas of the passages 73 ensure that the argon streams emerge from the ports 91 at a low velocity.” Therefore, no rejection under 112(b) applies to these limitations.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 15-16, 18-19, 22-23 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 5961689 A to Kobayashi in view of US 20190162473 A1 to Clauss, as further evidenced by US 20080182022 A1 to La Sorda.
Regarding claim 15. Kobayashi teaches a method of operating a furnace (fig. 2) having a melting chamber (see bath surface level 7 in fig. 2) with a periphery defined by
a surrounding wall structure (col. 5 ll. 35-40, “Heat generated by the combustion of fuel and oxidant within the furnace is radiated directly from the flame region 13, or indirectly from the combustion layer 6 by reradiation from the furnace roof and walls, through the protective layer 12 and to the furnace charge wherein it serves to heat and/or melt the furnace charge.” Thus, as seen in fig. 2, the furnace has a melting chamber with a periphery defined by a surrounding wall structure),
the method comprising:
providing the melting chamber with an atmosphere including air (before introducing the protective gas, the furnace would be understood to be provided with an atmosphere including air, see at least combustion layer 6, for example); and
directing inert gas to flow downward in the melting chamber (col. 4 ll. 53-54, “Injectors 8 are in flow communication with a source of protective gas (not shown).”) in a configuration of a curtain that adjoins the wall structure (col. 5 ll. 12-18 state, “However, in the practice of this invention, it is imperative that the combustion gas layer, as well as the protective gas layer, pass through the furnace at relatively low velocities so as to avoid excessive turbulence which would cause significant intermixing of the two layers resulting in adulteration of the protective gas layer with a concomitant loss of the protective capability of the protective gas layer.”
From this, one of ordinary skill in the art would recognize that injecting the protective gas with the low velocity described would cause the protective gas to flow downward along the wall of the melting chamber, at least until the protective gas layer reached the height of the injectors 8, as evidenced by La Sorda in para. 56, “The dense vapor forms a vapor curtain around the peripheral interior wall portions of the furnace crucible, expanding outward toward the open center of the furnace upon reaching and/or as it falls toward the molten metal surface 8. The inert vapor displaces the less dense air and/or other gases away from the molten metal surface and forces these gases through the open top of the furnace (as generally indicated by lines 34 and arrow 36 in FIG. 1). In addition, upon reaching the molten metal surface, the vapor expands to cover the entire surface 8 (as generally indicated by lines 32 in FIG. 1), forming an effective blanket or layer of inert gas that covers the molten metal surface to inhibit or prevent oxygen and/or other gases from contacting and/or penetrating the molten metal material being processed within the furnace.” – cited as an evidentiary reference) and reaches only partially around the periphery of the melting chamber (In examples A and B of col. 6 ll. 60-67, “Nitrogen gas was provided into the furnace through six injectors 21 (three in each end wall 22) at a second vertical distance of about 1.75 feet above the floor 20 at a total flow rate of 6000 SCFH to form a protective gas layer having a boundary shown at 23 which flowed at a velocity of about 1.4 fps. The boundary 23 is defined as the boundary surface where the concentration of nitrogen is greater than 95 volume percent.” Therefore, since the injectors are located only in the end walls 22, the gas curtain emanating from the injectors would reach only partially around the periphery of the melting chamber, i.e. the curtain of falling gas would only contact the end walls), to form an upper surface (upper boundary 9) by flowing horizontally from a lower end of the curtain, and to increase in depth such that the upper surface rises in the melting chamber to displace the air from the melting chamber (at least until the point where the upper boundary 9 reaches the height of the injectors 8, the protective gas would first flow downwards in the form of a curtain, as evidenced by La Sorda, and then flow horizontally along the bottom of the furnace and increase in depth to displace the air, until the upper boundary 9 reaches the point shown in fig. 1).
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But fails to explicitly teach a charge port configured for entry of metal pieces into the melting chamber, and
a discharge port configured to drain molten metal from the melting chamber;
Clauss teaches a charge port (fig. 1, charge port 21) configured for entry of metal pieces into the melting chamber (para. 15, “… a charge port 21 through which metal pieces are loaded into the melting chamber 15.”), and
a discharge port (fig 1, discharge port 25) configured to drain molten metal from the melting chamber (para. 15, “… a discharge port 25 through which molten metal is drained from the melting chamber 15.”).
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It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to implement suitable charging and discharging ports, as taught by Clauss, in the furnace of Kobayashi. Thus, the furnace of modified Kobayashi would teach a furnace having a charge port for entry of metal pieces and a discharge port for draining the molten metal. This would provide the predictable result and benefit of suitably loading and unloading the furnace to achieve the melting process, as suggested by Clauss in para. 15, “As shown schematically in FIG. 1, a melting furnace 10 has a wall structure 12 defining a melting chamber 15 and a combustion chamber 17. A door 20 is supported for sliding movement over a charge port 21 through which metal pieces are loaded into the melting chamber 15. Another door 24 is supported form movement over a discharge port 25 through which molten metal is drained from the melting chamber 15. A burner 26 is arranged to fire into the combustion chamber 17 to provide heat for melting the load.”
Regarding claim 16. Modified Kobayashi teaches the method as defined in claim 15 wherein the curtain is formed to reach around not more than one half of the periphery of the melting chamber (looking again to Examples A and B of Kobayashi, col. 6 ll. 60-67 state that, “Nitrogen gas was provided into the furnace through six injectors 21 (three in each end wall 22) …” Further, the dimensions of the furnace are noted in col. 6 ll. 47-49, “Each furnace had inside dimensions of a width of 6 feed, a length of 12 feed, and a height of 6 feet …” Therefore, as shown in figs. 3-4, the injectors are on the shorter end walls of the furnace. With this configuration, the curtain of protective gas flowing down from the injectors would only contact the shorter end wall portion of the total periphery, i.e. a total of 12 feet, made up of the two 6 foot end walls, of the 36 foot perimeter or about 33% of the total periphery).
Regarding claim 18. Modified Kobayashi teaches the method as defined in claim 15 wherein the inert gas is directed to enter the melting chamber at a low pressure (Kobayashi col. 5 ll. 12-18 state, “However, in the practice of this invention, it is imperative that the combustion gas layer, as well as the protective gas layer, pass through the furnace at relatively low velocities so as to avoid excessive turbulence which would cause significant intermixing of the two layers resulting in adulteration of the protective gas layer with a concomitant loss of the protective capability of the protective gas layer.” Where the velocity is understood to be substantially proportional to the supply pressure of the gas).
Regarding claim 19. Modified Kobayashi teaches the method as defined in claim 15 wherein the inert gas is directed to enter the melting chamber at a low velocity (Kobayashi col. 5 ll. 12-18 state, “However, in the practice of this invention, it is imperative that the combustion gas layer, as well as the protective gas layer, pass through the furnace at relatively low velocities so as to avoid excessive turbulence which would cause significant intermixing of the two layers resulting in adulteration of the protective gas layer with a concomitant loss of the protective capability of the protective gas layer.”).
Regarding claim 22. Modified Kobayashi teaches the method as defined in claim 15 wherein the inert gas comprises argon (Kobayashi col. 5 ll. 1-5, “Generally the protective gas will comprise nitrogen. Other gases which may be used to make up the protective gas include oxygen, argon and natural gas.”).
Regarding claim 23. Modified Kobayashi teaches the method as defined in claim 15 comprising directing streams of the inert gas at an effectively low pressure and an effectively low velocity to avoid entrainment of the air into the streams of the inert gas (Kobayashi col. 5 ll. 12-18 state, “However, in the practice of this invention, it is imperative that the combustion gas layer, as well as the protective gas layer, pass through the furnace at relatively low velocities so as to avoid excessive turbulence which would cause significant intermixing of the two layers resulting in adulteration of the protective gas layer with a concomitant loss of the protective capability of the protective gas layer.” Where the velocity is understood to be substantially proportional to the supply pressure of the gas).
Claim(s) 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kobayashi in view of Clauss as further evidenced by La Sorda as applied to claim 15 above, and further in view of the attached NPL to CLEAR, Surface Area to Volume Ratio, note an accessibility date of 7/14/13.
Regarding claim 17. Modified Kobayashi teaches the method as defined in claim 15 wherein the curtain is formed to reach around not more than one quarter of the periphery of the melting chamber (Kobayashi col. 4 ll. 47-48, “Protective gas is provided into the furnace through one or more injectors 8 …” Furthermore, when configuring a furnace with injectors, i.e. providing one or more injectors, it is understood that the dimensions of the furnace would remain the same. Therefore, a furnace provided with a lower number of injectors would be configured such that the falling protective gas curtain would cover less than 25% of the total periphery of the melting chamber).
To the extent that the Applicant disagrees with the Examiner’s characterization of the reference, as immediately explained above, the following rejection is provided:
Modified Kobayashi teaches the above detailed features, with the exception of explicitly disclosing wherein the curtain reaches around not more than one quarter of the periphery of the melting chamber.
However, with regards to the limitation of “the curtain reaches around not more than one quarter of the periphery of the melting chamber”, it is noted that modified Kobayashi provides an example of the injectors being provided only along the end walls of the furnace, see rejection to claim 2. Thus, the ratio of end wall length to the total periphery is directly related to the extent of the gas curtain’s reach.
CLEAR teaches the shape of the radiation surface increases the amount of heat transferred when the surface area is increased and decreases it when the surface area is decreased. As such it is observed that the end wall length to total periphery length ratio of the furnace is a result effective variable because increasing the ratio results in a more square furnace having a lower surface area for heat transfer and decreasing the ratio results in a more elongated rectangular furnace having a higher surface area for heat transfer. It would have been obvious to one of ordinary skill in the art at the time the invention was made to provide the curtain reaching around not more than one quarter of the periphery of the melting chamber, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. (See MPEP 2144.05 Section II A and B) and one would do so to decrease the operating costs of the device and/or allow the device to process different types of products.
Allowable Subject Matter
Claims 20-21 are 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.
The following is a statement of reasons for the indication of allowable subject matter:
Regarding claim 20. The combination of Kobayashi in view of Clauss and further evidenced by La Sorda, applied to claim 15, represents the closest prior art of record to the claimed invention. The prior art fails to teach, “directing the inert gas through a port structure only at a distal end of the melting chamber away from the charge port”, in addition to the rest of the claim.
Instead, when interpreting Kobayashi as only having one injector, from “one or more injectors 8”, the combination at best teaches the suitable charge door of Clauss applied to a wall, and then the one injector applied to a wall. While the configuration of only one injector 8 does mean that the port structure is only at one end of the melting chamber, there is nothing to prompt one of ordinary skill in the art to configure the end with the port structure opposite from the suitable charge port of Clauss.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Kurt J Wolford whose telephone number is (571)272-9945. The examiner can normally be reached 7:30 AM - 4:00 PM.
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/KURT J WOLFORD/Examiner, Art Unit 3762 /MICHAEL G HOANG/Supervisory Patent Examiner, Art Unit 3762
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