In re Lange, Appeal No. 80-568.

• Citation: 644 F.2d 856
• Decision Date: 12 March 1981
• Docket Number: Appeal No. 80-568.
• Parties: In re Emil LANGE.
• Court: United States Court of Customs and Patent Appeals

644 F.2d 856

In re Emil LANGE.

Appeal No. 80-568.

United States Court of Customs and Patent Appeals.

March 12, 1981.

Donald D. Evenson, Paul M. Craig, Jr., Davis S. Safran, Washington, D. C., for appellant; Joseph F. Nakamura, Washington, D. C., Sol., Jere W. Sears, Washington, D. C., of counsel.

Before MARKEY, Chief Judge, and RICH, BALDWIN, MILLER and NIES, Judges.

MILLER, Judge.

This is an appeal from a decision of the Patent and Trademark Office ("PTO") Board of Appeals ("board") which affirmed the examiner's rejections of claims 28, 31, and 42 on Cobine et al.¹ ("Cobine") under 35 U.S.C. § 102, and, under 35 U.S.C. § 103, claims 29, 30, and 32-34 on Cobine, claims 35-41 on Cobine in view of Farrer et al.² ("Farrer"), and claims 28-42 on appellant's German Auslegeschrift No. 1,285,594 ("`594"), published December 19, 1968, in view of appellant's British patent No. 1,205,646 ("`646"), published September 16, 1970. Appellant's application serial No. 254,537 was filed May 18, 1972, for "Electric Circuit Breaker With Means for Quenching Electric Arcs," as a continuation-in-part of application serial No. 719,763 ("parent"), filed April 8, 1968, which is a continuation of application serial No. 429,194 ("grandparent"), filed January 18, 1965. We reverse the board's decision affirming the rejections of claims 28, 31, and 42 under 35 U.S.C. § 102 and claims 28-42 under 35 U.S.C. § 103 on the '594 and '646 references. We affirm the board's decision approving the rejections under 35 U.S.C. § 103 of claims 29, 30, and 32-34 on Cobine and claims 35-41 on Cobine in view of Farrer.

The Invention

The invention relates to a circuit breaker which quenches an electric arc produced between electrodes by use of an electronegative gas, such as sulphur hexafluoride ("SF6"), selenium hexafluorideride ("SeF6"), trifluoromethylsulphur pentafluoride ("CF3 SF5"), or sulphur pentafluoride ("SF5") which is released from electrodes consisting of metallic and nonmetallic substances by the heat of the arc. The metallic substances include metals having strong cohesive forces such as tungsten and molybdenum. The nonmetallic substances are those which generate the desired electronegative gas when heated by an arc, such as an adduct of polytetrafluoride, possibly together with sulphur. Fluorine, sulphur or selenium is admixed with the nonmetallic substances. Figure 1 is illustrative:

The apparatus includes an arc quenching chamber 1, a fixed contact 2 electrically connected to a tubular electrode 7, a movable switch pin 3 having a contact tip 8 which operates as an electrode, spaces 4 and 5, partition 6, ring electrode 9, and electrically conductive connection piece 10. The electrodes 7, 8, and 9 are formed of the metallic and nonmetallic substances by melting, casting, sintering, decomposing, or superimposing the substances.

In order to break the circuit, the switch pin 3 is withdrawn from fixed contact 2; as this occurs, an arc is struck between electrodes 7 and 8. The heat from the arc causes electronegative gas to be emitted in the space 4 from the electrode surfaces. This gas aids in quenching the arc by forming negative ions having a great electron affinity. As the pin 3 continues to be withdrawn, tip 8 passes through the ring electrode 9 so that the arc burns between the electrode 7, the ring electrode 9, and the tip 8. The electronegative gas emitted from tip 8 and electrodes 7 and 9 increases the gas pressure in space 4. As the tip 8 leaves space 4 and enters space 5, the gas contained in space 4 rushes into space 5 through the ring electrode 9 exposing the arc to the gas.

Appellant's application stresses the importance of the location of the metallic and nonmetallic substances in the electrodes rather than in the walls of the arc quenching chamber.

The following claims are exemplary:

28. An electric circuit breaker comprising a plurality of electrodes between which at least one electric arc burns during circuit breaking, each of said electrodes consisting of a physical combination of metallic material and non-metallic material, said non-metallic material being such as to emit electro-negative arc quenching gas when subjected to the heat of said electric arc, said arc quenching gas having an ultimate dielectric strength of an order of magnitude greater than that of air wherein in and throughout the whole of each of said electrodes said metallic material and said non-metallic material are intimately intermixed and physically united.

35. A device for quenching electric arcs by the use of electronegative gases quenching the arc, especially an electric circuit breaker having quenching chamber walls and arc-drawing parts in the quenching chamber, said arc-drawing parts including electrode means containing at least one metallic substance, characterized in that the electrode means have surface areas serving as base points for the electric arc and the arc-drawing parts are composed of metallic components and non-metallic components giving off electronegative arc-quenching gases under the heat of the electric arc, said arc-quenching gases having an ultimate dielectric strength of an order of magnitude greater than that of air, the non-metallic components being physically combined with the metallic substances of the electrode means at least within the areas of the electrode means serving as base points of the electric arc so that the electronegative arc-quenching gases are given off by the electrode means inside of the arc itself independently of the distance of the quenching chamber walls and substantially immediately upon separation of the arc-drawing parts, and wherein said arc-drawing parts include fixed contact means on the inside of the quenching chamber, movable contact means having a contact tip and normally in contact with said fixed contact means, and at least one electrode means inside said quenching chamber and electrically connected with said fixed contact means, said fixed contact means, said one electrode means and said contact tip being composed of said metallic and non-metallic components, and further including a partition in said quenching chamber spaced from the fixed contact means in the direction of movement of said movable contact means, said partition forming two spaces and including another one of said electrode means arranged in said partition and provided with an opening to accommodate the movable contact means, said another electrode means being also composed of said metallic and non-metallic components so that electronegative gases under pressure flow from the one space containing the fixed contact means into the other space defined by said partition, when the contact pin leaves said one space, thereby quenching any arc which continues to burn between the moving contact tip and said another electrode means.

42. An apparatus for the quenching of electric arcs, especially of electric circuit breakers, in the quenching chamber of which there are provided non-metallic substances which emit, under the heat of the arc itself, electronegative gases which have the property that their molecules have the capability to attach themselves directly to electrons of the arc within the arc itself, said electronegative gases having an ultimate dielectric strength of an order of magnitude greater than that of air, characterized in that said non-metallic substances are intimately intermixed and physically united with the metallic substances of the electrodes serving as the base of the arc.

The Prior Art

The references are of two types: those applied against the claims and those cited to establish the level of ordinary skill or knowledge in the art. Cobine is the most pertinent reference applied against the claims and discloses a circuit interrupter having chamber walls which are coated and electrode surfaces which are impregnated with a silicofluoride material which releases silicon tetrafluoride gas ("SiF4") in response to the arc heat. The electrodes are so impregnated that when the gas is released it will sweep through the path of the arc. Because SiF4 has an ultimate dielectric strength of the same order of magnitude as air, Cobine suggests that SF6 could be used to increase the dielectric strength of the gas in the chamber. Farrer discloses specific structure of circuit interrupters which also emit arc-extinguishing gas from the walls of an arc-confining chamber in response to arc heat. The '594 reference is substantially similar to the Lange grandparent application and formed the basis for the grandparent's claim to foreign priority. The '646 reference discloses similar electrodes and chamber structure with additional details concerning manufacture of the electrode chamber.³

Three additional references have been made of record, and both the PTO and appellant appear to agree that they indicate the level of ordinary skill in the art. The Mandelcorn et al. patent⁴ ("Mandelcorn") states that:

Electronegative gases ... and fluorine compounds may be clathrated. Process by which molecules of one substance are completely enclosed within another substance. Particularly useful clathrated products are obtained with fluorine-containing electronegative gases. Examples of such last-mentioned fluorine compounds are sulfur hexafluoride, selenium hexafluoride, and trifluoromethyl sulfur pentafluoride. Likewise, fluorocarbons such as perfluorobutane and perfluorohexane can be clathrated. The fluorinated and other electronegative gases are particularly suitable when in clathrate form for use in switchgear and circuit breakers. The solid clathrates containing these compounds may be disposed near arcing contacts so that the heat developed by the electrical arc will decompose the clathrate and release copious quantities of the electronegative gas which will assist in interrupting the electrical arc. The clathrate solids may be adhesively coated on the breaker walls to provide a layer thereof near the arcing contacts.

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