US2867786A - Mounting means for carbon electrodes or graphite electrodes - Google Patents

Mounting means for carbon electrodes or graphite electrodes Download PDF

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Publication number
US2867786A
US2867786A US580879A US58087956A US2867786A US 2867786 A US2867786 A US 2867786A US 580879 A US580879 A US 580879A US 58087956 A US58087956 A US 58087956A US 2867786 A US2867786 A US 2867786A
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United States
Prior art keywords
electrodes
nipple
surfaces
graphite
nipples
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Expired - Lifetime
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US580879A
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Doetsch Ernst
Klier Gregor
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C CONRADTY
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Conradty Fa C
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Priority to DEC11158A priority Critical patent/DE1018565B/en
Application filed by Conradty Fa C filed Critical Conradty Fa C
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Publication of US2867786A publication Critical patent/US2867786A/en
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    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B7/00Heating by electric discharge
    • H05B7/02Details
    • H05B7/14Arrangements or methods for connecting successive electrode sections
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Process efficiency
    • Y02P10/25Process efficiency by increasing the energy efficiency of the process
    • Y02P10/256Design or operational measures for increasing the efficiency of electric conversion
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Process efficiency
    • Y02P10/25Process efficiency by increasing the energy efficiency of the process
    • Y02P10/256Design or operational measures for increasing the efficiency of electric conversion
    • Y02P10/259Design or operational measures for increasing the efficiency of electric conversion in electric arc furnaces
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S403/00Joints and connections
    • Y10S403/05Carbon electrode
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S411/00Expanded, threaded, driven, headed, tool-deformed, or locked-threaded fastener
    • Y10S411/924Coupled nut and bolt
    • Y10S411/929Thread lock
    • Y10S411/938Distorted thread
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00Joints and connections
    • Y10T403/58Joints and connections including ancillary means blocking disconnection of joint
    • Y10T403/589Cam or thread lock
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00Joints and connections
    • Y10T403/68Screw or cam

Description

Jan. 6, 1959 E. DOETSCH AL r 2,867,786 MOUNTING MEANS FOR CAR ELECTRODES OR GRAPHITE ELECTRODES Filed April 26. 1956 2 Sheets-Sheet 1 fflvenfor's fk/vsr DOETJCH Arno? Jan. 6, 1959 E. DOETSCH ET AL 2,867,786 MOUNTING MEANS FOR CARBON CTRODES OR GRAPHITE ELECTRO Filed April 26, 1956 2 Sheets-Sheet 2 fen 6r .Oosnscw 4 6195608 A4 05/? frequently give rise to breakdowns.

United Stats Patent O F MOUNTING MEANS FOR CARBON ELECTRODES OR GRAPHITE ELECTRODES Ernst Doetsch, Numberg, and Gregor Klier, Schwaig, near Nurnberg, Germany, assignors to C. Conradty, Numberg, Germany, a partnership Application April 26, 1956, Serial No. 580,879 Claims priority, application Germany April 29, 1955 6 Claims. (Cl. 339-263) Our invention relates to improved mounting means for carbon electrodes or graphite electrodes of the type used in ovens heated by an electrical arc and, more particularly, to nipple connections for such electrodes.

Experience has shown that such nipple connections When the nipple connection becomes loose the nipples are liable to be overheated as, in such event, they must conduct the entire current, whereas in normal operation the nipples only carry a portion or about thirty percent of the current, provided that the end faces of the electrodes and the cooperating end faces of the conductors are held by the nipple in perfect contact with a satisfactory pressure en-' gagement. The overheating of the nipple is liable to cause breakage of the same so that the electrodes will come apart. This, however, has disastrous consequences for the operation of the oven. The least that is liable to happen is a restriction of the electrode conductor owing to increased oxidation of the electrode material, such restriction involving a permanent risk of breakage and increasing the rate of consumption of the electrodes.

Where conical nipples are employed which may be tightened in a particularly simple manner by a turn of about two revolutions only, the nipples are particularly liable to become loose and to consequently come off.

A cause for the nipples becoming loose may be either the mounting of the electrodes by unskilled laborers or vibration of the oven. To safeguard the connection established by the nipples, it has been proposed heretofore to insert pins of carbon or graphite at the point of connection either into the end faces of the electrodes or at a certain distance therefrom through the nipple boxes up to a bore of the nipple so that relative rotation cannot be effected.

Apart from the additional cost of labor the nipple box is weakened by such arrangement, since caloric stresses may cause cracks that originate in the bore. Moreover, experience has shown that such securing pins cannot prevent the co-operating end faces from being slightly spaced thus causing overheating of thenipples as previously explained.

The type of thread most frequently used on an international scale for graphite electrodes, is the so-called trapezoidal thread, which has a constant diameter, but which for conical nipples is modified to constitute a trapezoidal thread having a diameter that varies as the conical cross section varies. With this type of thread the machining used heretofore resulted in smooth surfaces. Because of the lubricating properties of the graphite the smooth surfaces will easily slide upon each other, particularly where the oven is subject to powerful vibrations, thus causing the nipple connection to become loose.

One feature of the present invention is electrodes of carbon or of graphite in which the current-conducting co-operating surfaces of the threads of the nipples and of the electrodes have a structure reducing the tendency of the thread to become loose and reducing the transitional electrical resistance at the same time.

, 2,867,786 Patented Jan. 6, 1959 According to another feature of the invention the threads of the nipples and electrodes are profiled. Experience has shown that such profiled surfaces will interlock in such a manner as to prevent accidental relative displacement.

The thread surfaces may be profiled in any suitable manner. Thus, according to a further feature of the invention said surfaces may be e. g. roughened, toothed, undulated or corrugated.

According to still another feature of the invention the end faces of the nipples and the electrodes respectively engaging each other may also be treated in a similar manner as stated for the co-operating surfaces of the threads.

It is a particular advantage of our invention that it can be applied to existing types of threads that conform to international standards, and that when the novel method is applied to a nipple connection it does not require additional steps of assembly and does not result in additional cost.

In the accompanying drawing,

Fig. 1 represents a fragmentary longitudinal section of a cylindrical nipple and illustrates the normal type of thread, 1

Fig. 2 is a fragmentary longitudinal section of a cylindrical nipple produced in accordance with the present invention,

Fig. 3 corresponds to Fig. 1 but shows the normal thread of a conical nipple,

Fig. 4 corresponds to Fig. 2 but shows the thread of a conical nipple treated in accordance with the present invention, t

Fig. 5 is a fragmentary perspective view of a cylindrical nipple having normal threads, and

Fig. 6 is likewise a fragmentary perspective View of a cylindrical threaded nipple but having threads formed in accordance with the present invention.

Figs. 79 are fragmentary, sectional, perspective views of electrodes adapted to co-operate with nipples according to Figs. l-6, said figures showing three different kinds of profiled thread surfaces.

Figs. 1 and 3 illustrate a normal type of thread of a cylindrical nipple and of a conical nipple respectively which may be, according to the invention, modified by having the current-conducting co-operating surfaces a of the threads of the nipples profiled by roughening, as illustrated in Figs. 2 and 4 respectively. Such roughening may be made by treating the respective surfaces with sand jets or jets of silicon carbide.

Fig. 7 shows an electrode b having its thread faces 0 roughened. Of course, the co-operating surfaces of the nipple and the electrode may be profiled in any other suitable way, e. g. said co-operating surfaces may be provided with teeth, as shown on thread faces d of the electrode shown in Fig. 8 of the drawing.

According to another modification the co-operating surfaces may be undulated in the manner shown in Fig. 6 of the drawing respectively or corrugated as shown in the embodiment of the electrode shown in Fig. 9' of the drawing.

This embodiment differs from that shown in Fig. 6 in that the corrugated grooves of the threads e are annular while in the embodiment according to Fig. 6 these grooves extend radially.

Of course the peripheral surfaces of the threads of the nipples as well as of the cooperating surfaces of the electrodes may be roughened in accordance with any one of the previously described embodiments.

In addition to the surfaces of the threads of the nipples and of the electrodes, the meeting end faces of the nipples and the electrodes may be treated as shown in Figs. 7-9; an end face 1 being shown in Fig. 7 as roughened; an end face g being shown in Fig. 8 as toothed, and an end face h being shown in Fig. 9 as annularly corrugated.

The corrugated surfaces may be produced by milling the normal surfaces with a rotary milling tool having a slightly eccentric mounting and thus producing rhythmic'a'l irregularity.

When a normal nipple and electrode are screwed together, the smooth surfaces slide upon each other and 'areliable to become loose because of a lubricating effect peculiar to graphite, but when such surfaces are provided with corrugations of short wave length to form crests and recesses, these corrugations will interlock when the thread is tightened whereby a natural safeguard against loosening of the connection is attained.

Another advantage of this method resides in the fact that it results in savings which offset any additional cost.

By constructing the thread faces and the end faces in 'acco'rda'nce'with the presentinven'tion the electrode connection is not only secured against accidental loosening, but will also result in a considerable reduction of the transitionalelectrical resistance by increasing the contact-surface area and the contact pressure, whereby current losses are reduced and an unnecessary heating of the electrical conductors and the consequent oxidation is avoided.

"We claim:

1. A nipple connection for electrodes of carbon or graphite comprising threads with current-conducting co operating surfaces for the nipples and the end faces of the electrodes, and means formed integral with the surfaces before assembly of the nipples and electrodes to reduce the tendency of the thread becoming loose and to reduce the electrical resistance therebetween'to a value below that of smooth-surface electrode threads and end faces of corresponding size.

2. A nipple connection for electrodes according to claim 1, in which the surfaces are undulated.

3. A nipple connection for electrodes according to claim 1, in which the surfaces are tooth-shaped in cross section.

4. A nipple connection for electrodes according to claim 1, in which the surfaces are corrugated.

5. A nipple connection for electrodes according to claim 1, in which the'surfaces are roughened.

6. A screw-threaded connection for carbon and graphite electrodes comprising a threaded member having the contacting surface faces thereof mechanically roughened to provide'a locking between the threaded connection and to form current-conducting and co-operating surfaces that reduce the electrical resistance therebetween to a value below that of smooth-surface. electrodes of corresponding size.

References Cited :in the file of'this patent UNITED STATES PATENTS 1,070,247 .I-Iaines Aug. 12, 1913 2,093,390 Wyckoflf Sept. 14, 1937 2,135,637 Gade Nov. 8, 1938 2,301,181 Ilsemann Nov. 10, 1942 2,441,188 Earhart May 11, 1948 2,484,644 Poupitch- Oct. 11, 1949 FOREIGN PATENTS 351,151 Great Britain June 25, 1931 472,856 France Aug. 21, .1914 533,761 'Great Britain Feb. '19, 1941

US580879A 1955-04-29 1956-04-26 Mounting means for carbon electrodes or graphite electrodes Expired - Lifetime US2867786A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DEC11158A DE1018565B (en) 1955-04-29 1955-04-29 Nipple threaded connection for carbon and graphite electrode

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US2867786A true US2867786A (en) 1959-01-06

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3238985A (en) * 1963-05-09 1966-03-08 Allen F Reid Threaded devices with antirotational means
US3339389A (en) * 1965-02-16 1967-09-05 Nat Lock Co Method of forming self-locking threaded fastening member
US4432663A (en) * 1980-11-03 1984-02-21 Western Electric Company, Inc. Cable pulling eye
EP1441570A1 (en) * 2003-01-24 2004-07-28 Sgl Carbon Ag Carbon electrodes and its connection elements with directionally structured contact surfaces
EP1528840A1 (en) * 2003-10-31 2005-05-04 Sgl Carbon Ag Threaded connection for carbon and/or graphite electrode columns
US20050186048A1 (en) * 2004-02-25 2005-08-25 Robert Dicke Thread-forming screw fastener
US20080050200A1 (en) * 2006-08-26 2008-02-28 Kuo-Tai Su Saw Tooth Screw

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1070247A (en) * 1910-07-09 1913-08-12 Frank P Haines Self-locking screw.
FR472856A (en) * 1914-05-26 1914-12-22 Fr Des Electrodes Soc Improvement in joint connections carbon electrodes
GB351151A (en) * 1929-08-01 1931-06-25 Siemens-Planiawerke Aktiengesellschaft Fur Kohlefabrikate
US2093390A (en) * 1934-12-19 1937-09-14 Union Carbide & Carbon Corp Means and method of making electrode joints
US2135637A (en) * 1935-04-26 1938-11-08 Standard Pressed Steel Co Setscrew
GB533761A (en) * 1939-11-24 1941-02-19 Coventry Gauge & Tool Co Ltd Improvements in screw threads
US2301181A (en) * 1941-10-23 1942-11-10 Eric M Ilsemann Self-locking threaded fastening element
US2441188A (en) * 1945-06-08 1948-05-11 Beech Aircraft Corp Tension bolt joint
US2484644A (en) * 1945-04-13 1949-10-11 Illinois Tool Works Self-locking and sealing screw

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE932813C (en) * 1952-07-09 1955-09-08 Siemens Planiawerke Ag Threaded connection to the piecing of graphite and carbon electrodes

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1070247A (en) * 1910-07-09 1913-08-12 Frank P Haines Self-locking screw.
FR472856A (en) * 1914-05-26 1914-12-22 Fr Des Electrodes Soc Improvement in joint connections carbon electrodes
GB351151A (en) * 1929-08-01 1931-06-25 Siemens-Planiawerke Aktiengesellschaft Fur Kohlefabrikate
US2093390A (en) * 1934-12-19 1937-09-14 Union Carbide & Carbon Corp Means and method of making electrode joints
US2135637A (en) * 1935-04-26 1938-11-08 Standard Pressed Steel Co Setscrew
GB533761A (en) * 1939-11-24 1941-02-19 Coventry Gauge & Tool Co Ltd Improvements in screw threads
US2301181A (en) * 1941-10-23 1942-11-10 Eric M Ilsemann Self-locking threaded fastening element
US2484644A (en) * 1945-04-13 1949-10-11 Illinois Tool Works Self-locking and sealing screw
US2441188A (en) * 1945-06-08 1948-05-11 Beech Aircraft Corp Tension bolt joint

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3238985A (en) * 1963-05-09 1966-03-08 Allen F Reid Threaded devices with antirotational means
US3339389A (en) * 1965-02-16 1967-09-05 Nat Lock Co Method of forming self-locking threaded fastening member
US4432663A (en) * 1980-11-03 1984-02-21 Western Electric Company, Inc. Cable pulling eye
EP1441570A1 (en) * 2003-01-24 2004-07-28 Sgl Carbon Ag Carbon electrodes and its connection elements with directionally structured contact surfaces
US20040192088A1 (en) * 2003-01-24 2004-09-30 Stefan Baumann Carbon electrodes and connection elements of the electrodes having directionally structured contact surfaces
US6925104B2 (en) 2003-01-24 2005-08-02 Sgl Carbon Ag Carbon electrodes and connection elements of the electrodes having directionally structured contact surfaces
EP1528840A1 (en) * 2003-10-31 2005-05-04 Sgl Carbon Ag Threaded connection for carbon and/or graphite electrode columns
US20050186048A1 (en) * 2004-02-25 2005-08-25 Robert Dicke Thread-forming screw fastener
US7101133B2 (en) * 2004-02-25 2006-09-05 A-Z Ausrustung Und Zubehor Gmbh & Co Kg Thread-forming screw fastener
US20080050200A1 (en) * 2006-08-26 2008-02-28 Kuo-Tai Su Saw Tooth Screw
US7862280B2 (en) * 2006-08-26 2011-01-04 Taiwan Shan Yin International Co., Ltd. Saw tooth screw

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DE1018565B (en) 1957-10-31
FR1148740A (en) 1957-12-13

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