US3444305A - Electrode head for electric furnace electrodes - Google Patents

Description

Sheet of 4 May 13, 3969 A. H. TURNER ELECTRODE HEAD FOR ELECTRIC FURNACE ELECTRODES Filed June 13, 1968 e zrw r- Sheet 2 m w\ 3 3 N A. H. TURNER May H, 1969 ELECTRODE HEAD FOR ELECTRIC FURNACE ELECTRCDES Filed June 13, 1968 May 13, 1969 A. H. TURNER 3,444,305

ELECTRODE HEAD FOR ELECTRIC FURNACE ELECTRODES Filed June 13, 1968 Sheet Z F1" 6. 5

y 3, 1969 4 A. H. TURNER 3,444,305

ELECTRODE HEAD FOR ELECTRIC FURNACE ELECTRODES Filed June 15, 1968 Sheet 4 01'4 Rm: 7 64 F168 30 ji/se -/38 I z l 1 15 2 t T" ll t m I. H" 283 l l i I .7

United States Patent Int. Cl. H0511 7/10 U.S. CI. 13-16 Claims ABSTRACT OF THE DISCLOSURE An electrode head for use with a cylindrical electric furnace electrode comprising a body having a cylindrically curved front member, a cylindrically curved contact shoe removably mounted in a stationary position on the body against the curved front member, said contact shoe having passages therein for carrying cooling water, a generally U-shaped clamping band removably mounted on the body for clamping the electrode against the contact shoe, said band having passages therein for carrying cooling water, a bar for applying a clamping force to the ends of said band, and a plurality of curved lining plates removably mounted on the inside of said band to engage the electrode and protect the band against Wear and electrical arcing.

This application is a continuation-in-part of my earlier co-pending application, Ser. No. 58 4, 216, filed Oct. 4, 1966, now abandoned.

This invention relates to a new and improved water cooled electrode head for use with electric furnace electrodes or the like. In various aspects, the present invention may be regarded as an improvement upon the invention disclosed and claimed in the prior patent of the present applicant, No. 2,997,511, issued Aug. '11, 1961.

One object of the present invention is to provide a new and improved electrode head having a water cooled contact shoe, which carries the electric current to the electrode, and a water cooled clamping band or member, which is employed to clamp the electrode against the shoe.

A further object is to provide a new and improved electrode head of the foregoing character having a single large contact shoe which is stationary, together with a movable clamping band.

'It is a further object to provide a new and improved electrode head of the foregoing character, which is constructed so that the contact shoe may readily be removed and replaced, when maintenance is necessary, so as to minimize the time and labor required for such maintenance.

Another objeect is to provide such a new and improved electrode head, in which the water cooled clamping band is provided with curved lining plates or segments which are adapted to protect the water cooled clamping band again-st wear and damage due to arcing.

A further object is to provide an electrode head of the foregoing character, in which the lining plates are readily removable and replaceable, so as to minimize the time and labor required to perform maintenance work on the electrode head.

Still another object is to provide such a new and improved electrode head which is highly economical, both as to original cos-t and the cost of maintenance.

Further objects and advantages of the present inven tion will appear from the following description, taken with the accompanying drawings, in which:

FIG. 1 is a general plan view of an electrode head to be described as an illustrative embodiment of the present invention, the electrode head being shown in conjunction with the associated supporting and operating equipment.

FIG. 2 is an enlarged vertical section, taken generally along the broken line 22 in FIG. 1.

FIG. 3 is a fragmentary vertical section, taken generally along the line 3-3 in FIG. 1.

FIG. 4 is an elevational view, partly in section along the broken line '4-4 in FIG. 1.

FIG. 5 is a plan view of a modified electrode head, to be described as a second illustrative embodiment of the present invention.

FIG. 6 is an elevational section, taken generally along the broken line 66 in FIG. 5.

FIG. 7 is another elevational section, taken generally along the line 77 in FIG. 6.

FIG. 8 is a fragmentary vertical section, taken generally along the line 88 in FIG. '5.

FIG. 9 is another fragmentary vertical section, taken generally along the line 99 in FIG. 5.

As already indicated, FIGS. 1-4 of the drawings illustrate an electrode head 10 which is adapted to hold a cylindrical electrode 12, of the type employed on electric furnaces or the like. It will be understood that an electric furnace employs a plurality of such electrodes and that each electrode is provided with a separate electrode head. The purpose of the electrode head 10 is to supply electric current to the electrode 12 and also to provide at least some of the support for the electrode. 'Normally, the electrode 12 is made of carbon, either with or without a cylindrical sheath of metal. Typically, the electrode 12 and the electrode head 10 are quite large. Thus, the particular electrode head 10 which is illustrated in the drawing is intended for use with an electrode having a diameter of 12 inches. Much larger electrodes and electrode heads are also frequently employed. It will be evident that the weight of such electrodes is quite great, and that the operating electrical currents for such large electrodes are very high.

The illustrated electrode head 10 comprises a body or supporting base 14, which is adapted to be mounted on the outer end of a mast arm or boom 16. A flange 18 is welded or otherwise secured to the outer end of the arm 16, which is cylindrical in shape. The body 14 is provided with a mounting flange 20 which is adapted to be secured to the flange 1 8 by means of a plurality of bolts 22 or the like.

The illustrated body 14 is provided with a bottom plate 24, a top plate 26, and a pair of side plates 28 and 30, all of which are welded or otherwise secured to the flange 20. The plates 22-30 are welded together to form a box-like structure, as will be evident from FIGS. 1 and 2.

A flat vertical plate 32 is welded or otherwise secured to the front edges of the plates 2230. It will be seen that a cylindrically curved front plate 34 is connected to the plate 32 by means of a plurality of horizontal ribs or fins 36, which may be welded or otherwise secured to the plates 32 and 34-.

It will be seen from FIG. 1 that a curved contact shoe 40 is mounted on the front end of the body 14. The shoe 40 is adapted to engage the cylindrical electrode 12, for the purpose of transmitting electrical currents to the electrode. The rear side of the curved contact shoe 40 is mounted against the curved front plate 34. It will be seen from FIG. 4 that the contact shoe 40 has a rearwardly projecting flange or shoulder 42 adjacent its upper end. The flange 40 extends rearwardly over the upper edge of the curved front plate 34, and also over a portion of the plate 32.

The lower end of the contact shoe 40 is supported by a horizontal plate 44 which is welded or otherwise secured to the lower edges of the plates 32 and 34. The plate 44 projects forwardly beyond the curved front plate 34, to form a supporting ledge for the contact shoe 40.

To provide good electrical conductivity, the contact shoe is preferably made of copper, but other highly conductive materials may be employed. The illustrated contact shoe 40 is of the construction disclosed and claimed in the a-pplicants Patent No. 2,997,511, issued Aug. 11, 1961. Thus, the shoe 40 comprises a body 48 which is preferably in the form of a copper casting. A series of channels 50 are formed in the front or concave side of the body 48, to provide passages through which water or some other fluid coolant may be circulated in the finished shoe. A curved closure plate 52 is mounted on the front of the body 48 and is welded thereto, so as to close the front sides of the channels or passages 50. In FIG. 4, the welds between the body 48 and the plate 50 are indicated at 54 and 56.

In the embodiment of FIGS. 1-4, electricity and water are carried to the shoe 40 by means of a pair of metal tubes 60 which are connected into openings 62 formed in the upper end of the body 48. The tubes 60 are preferably made of copper to provide good electrical conductivity. The tubes 60 may be welded or brazed into the openings 62 or may be secured therein by means of screw threads. It will be understood that the openings 62 connect with the opposite ends of the passages 50, so that the cooling water may be brought to the contact shoe by one tube, and carried away by the other tube.

It will be seen from FIG. 4 that the tubes 60 come down to the contact shoe 40 from a bus bar 64. For this reason, the tubes 60 are commonly known as downcomers. The tubes 60 extend upwardly from the contact shoe 40 and are bent rearwardly to form horizontal legs 60 which are connected to the bus bar 64 by means of a clamp 68. The cooling water may be supplied to the tubes 60 by means of hoses 70 or the like.

Suitable supports 72 and 74 may be provided for the bus bar 64. The supports 72 and 74 may be clamped or otherwise secured to the mast arm 16.

It will be seen from FIG. 1 that a U-shaped clamping band 80 is employed to clamp the electrode 12 against the contact shoe 40. The clamping band 80 is preferably made of stainless steel, or some other similar material which is strong and highly resistant to corrosion, and which has a relatively low electrical conductivity.

As shown in FIGS. 1 and 2, the opposite ends of the clamping band 80 are connected to a pull bar 82 which extends through slots 84 in the band. The bar 82 also extends through slots 96 in a pair of stationary bearing members 98 which are mounted on the body or base 14 of the electrode head.

Within the body 14, the central portion of the bar 82 is pivotally connected to a forked member 100, by means of a pivot bolt 102 or the like. The forked member 100 is employed to transmit clamping force to the bar 82. It will be seen that retaining bolts 104 are mounted in the opposite ends of the bar 82 to retain the ends of the clamping band 80 on the bar.

In the illustrated construction of FIGS. 14, force is applied to the bar 82 by means of a lever 108 which is swingable about a pivot 110, mounted on the lower wall 24 of the body 14. The lower end of the lever 108 is connected to the pivot 110. The lever projects upwardly from within the body 14, and through a slot 112, formed in the top plate 26 of the body 14.

The forked member 100 is connected to or formed integrally with another forked member 114, which is connected to an intermediate point on the lever 108 by means of a pivot 116.

In the illustrated construction, the lever 108 is operated by a hydraulic cylinder 120, mounted on a supporting member 122 which is clamped or otherwise secured to the mast arm 16. A rod or link 124 is connected between the lever 108 and the piston rod 126 of the hydraulic cylinder 120.

A biasing spring 126 is preferably employed to apply clamping force to the rod 124. Thus, the spring 126 tends to move the rod 124 rearwardly, or toward the right as shown in FIG. 4, so as to swing the lever 108 in a rearward direction, and thereby apply clamping force to the band 80. The illustrated spring 126 is in the form of a compression coil spring, which is compressed between a stationary plate or member 128 and a plate or disc 130, secured to the rod 124. The stationary plate or member 128 is secured to the supporting member 122.

The hydraulic cylinder may be employed to move the rod 124 in either direction, so as to tighten or loosen the clamping band 80. As the rod 124 is moved to the right, the clamping band 80 is pulled tighter around the electrode 12, so that the electrode is clamped more tightly against the contact shoe 40. As the rod 124 is moved to the left, the clamping band 80 is loosened. Such movement of the rod 124 compresses the spring 126.

As shown in FIGS. 2-4, the clamping band 80 is formed with a series of passages 134 therein to carry cooling water. In the illustrated construction, the passages 134 are formed by fabricating the clamping band 80 from a plurality of parts, comprising inner and outer plates 136 and .138, and upper and lower walls 140 and 142, which are welded or otherwise secured to the plates 136 and 138. The plates 136 and 138 are spaced apart, so as to form passages 134. A plurality of dividers 144 are preferably mounted between the plates 136 and 138, to act as baffies so that the cooling water will have to flow along a winding or serpentine path between the plates. Each divider 144 extends only part way along the length of the band 80, so that all of the passages 134 will be interconnected. Additional plates 145 are employed around the slots 84.

Hoses 146 and v148 or the like may be connected to the opposite ends of the clamping band 80 so that cooling water may be circulated through the passages 134. The water is supplied by one of the hoses and is carried away by the other hose.

It will be seen from FIG. 3 that the lower edge of the clamping band 80 is supported by spacing blocks 150 which rest upon the horizontal plate 44. The sides of the band 80 are confined by vertical flange plates 152 which are secured to the plate 44 by means of brackets 154 and bolts 156, or other suitable means.

It is preferred to employ lining plates or shoes between the clamping band 80 and the electrode 12. Two such lining plates 160 are employed in the illustrated construction. Each lining plate 160 is cylindrically curved to fit closely between the clamping band 80 and the electrode 12. The lining plates 160 are preferably made of stainless steel or some other material which is resistant to corrosion and wear, and which affords a high electrical resistance. The lining plates .160 prevent damage to the water cooled clamping band 80 due to wear and electrical arcing. The wear occurs between the lining plates 160 and the electrode 12. Moreover, if there is any electrical arcing, it occurs between the electrode 12 and the lining plates 160, so that the water cooled clamping band 80 is not damaged. The provision of the lining plates 160 tends to prevent electrical arcing, by increasing the electrical resistance between the electrode 12 and the clamping band 80, so that virtually all of the current flows to the electrode 12 through the contact shoe 40.

The lining plates 160 are mounted on the clamping band 80 so as to be readily removable and replaceable. In the illustrated construction, each plate 160 is secured to the clamping band 80 by means of a pair of clips or books 162. It will be seen from FIG. 4 that the clips 162 are adapted to hook over the upper edge of the clamping band 80. The clips 162 are welded or otherwise secured to the lining plates .160. Each clip 162 is generally Z- shaped, as will be evident from FIG. 4.

In the operation of the electrode head of FIGS. 1-4, clamping force is normally applied to the clamping band 80 by the biasing spring 126, which urges the rod 124 rearwardly or to the right, as seen in FIGS. 1 and 4. Additional clamping force is applied to the rod 124 by the hydraulic cylinder 120.

The clamping force applied to the rod 124 tends to swing the lever 108 in a clockwise direction, so that a rearward pull is exerted on the bar 82. The ends of the bar 82 are effective to transfer the pull to the opposite ends of the clamping band 80. Thus, the electrode 12 is clamped against the contact shoe 40.

The hydraulic cylinder 120 may be employed to move the rod 124 to the left so as to release the pull on the clamping band 80. The electrode 112 can then be moved vertically between the contact shoe 40 and the clamping band 80. When the electrode has been readjusted, the hydraulic cylinder 120 is reversed so that the electrode will again be clamped between the band 80 and the shoe 40.

During normal operation, electrical currents travel from the bus bar 64 to the contact shoe 40 along the tubes or downcomers 60. The electrical currents pass between the shoe 40 and the electrode 12.

The downcomer tubes 60 are also employed to supply cooling water to the contact shoe 40. By means of the hoses 70, cooling water is supplied to one of the tubes 60 and is carried away from the other tube.

Similarly, cooling water is circulated through the clamping band 80 by the hoses 146 and 148. The water is supplied to one end of the clamping band 80 by one of the hoses and is carried away by the other hose.

Due to ordinary wear, it may occasionally be necessary to replace the contact shoe 40. The shoe 40 may readily be removed from the electrode head by loosening the clamping band 80 and removing the clamp 68 by which the downcomer tubes 60 are secured to the bus bar 64. The contact shoe 40 may then be lifted from the electrode head. A new contact shoe may then simply be dropped between the electrode and the curved front plate 34 on the body 14 of the electrode head. The new contact shoe may be provided with a new pair of downcomer tubes 60, or the old downcomer tubes may be transferred to the new shoe. After the new contact shoe is place on the electrode head, the downcomer tubes may be reclamped to the bus bar 64.

The lining plates 160 for the clamping band 80 may also be removed and replaced very readily. Thus, the lining plates 160 may simply be lifted off the clamping band 80 after the clamping band has been loosened from the electrode 12. A new pair of lining plates may then be lowered between the electrode 12 and the clamping band 80. The clips 162 are effective to retain the lining plates 160 on the clamping band 80.

Both the contact shoe 40 and the lining plates 160 may be removed and replaced in the field, with the expenditure of a minimum amount of time and labor. There is no need to remove the entire electrode head. The shutdown of the electric furnace to replace the contact shoes and the lining plates is of very short duration, so that very little production is lost. The old contact shoe can be returned to the factory for rebuilding, which can be accomplished for much less than its original cost.

Thus, the maintenance cost of the electrode head is very low. Due to the eflicient and functional construction of the electrode head, the initial cost is also low. Moreover, the electrode head is efficient in operation and is capable of giving long trouble-free service.

FIGS. 5-9 illustrate a modified electrode head 210 which is generally similar to the electrode head 10 of FIGS. 1-4, while being modified in certain respects. Insofar as the electrode head 210 is the same as electrode head 10, the same reference characters have been applied to the corresponding components of the electrode head 210, so that the previous description of these components may be utilized, to avoid any unnecessary duplication of the description. Thus, only the differences or modifica tions embodied in the electrode head 210 need be described in detail.

It will be seen that the electrode head 210 comprises a curved contact shoe 240, made of a material having good electrical conductivity. The shoe 240 comprises a body 248 of modified construction, as will be described in detail presently. As before, the body 248 is preferably in the form of a copper casting, having a series of channels 250, to provide passages through which cooling water may be circulated in the finished shoe. A curved closure plate 252 is mounted on the front of the body 248 and is welded thereto, so as to close the front sides of the panels or passages 50. In FIG. 6, the welds between the body 248 and the plate 250 are indicated at 254 and 256.

The body 248 of the shoe 240 is modified in that the body is formed with a solid arm or extension 257, adapted to supply electricity to the shoe 240. Thus, with respect to supplying electricity, the solid piece 257 performs the function previously performed by the downcomer tubes 60 of FIGS. 1-4. The arm 257 is preferably cast integrally with the body 248. In the illustrated con struction the arm 257 is formed with a plurality of reinforcing ribs 259.

The electricity is supplied to the electrode head 210 by a pair of bus bars 264 which may be in the form of large tubes made of copper or the like. The arm 257 is clamped directly to the bus bars 264. Thus, the upper end of the illustrated arm 257 is formed with a clamping bracket 265 adapted to engage the bus bars'264. A counplementary clamping plate 267 is secured to the bracket 265 by means of a plurality of clamping bolts 268 so that the bus bars 264 may be clamped between the bracket 265 and the plate 267.

The hollow tubular 'bus bars 264 are preferably employed to circulate cooling water to and from the electrode head. Thus, the water is supplied by one bus bar 264, while being carried away by the other bus bar.

In the illustrated construction, one of the bus bars 264 is connected to one end of the contact shoe 240 by means of a pipe 269 and a hose 271, which is preferably of the flexible metal type. The other end of the contact shoe 240 is connected to one end of the water cooled clamping band by means of a pipe 273 and a hose 275. The opposite end of the clamping band 80 is connected to the other bus bar 264 by a hose 2'77 and a .pipe 279. The hoses 275 and 277 are preferably of the flexible metal type. While the pipes and hoses 269-279 are employed to carry the cooling water, they do not conduct the electricity to any substantial extent. The electricity is conducted by the solid arm 257. It will be understood that the pipes and hoses 269-279 replace the tubes 60 and the hoses 1 46 and 148, with respect to the function of supplying cooling water to the contact shoe 240 and the clamping band 80.

In the electrode head 210, clamping band 80 is actuated by a modified pull bar 282 which is similar to the pull bar 82, previously described. The ends of the pull bar 282 are slidably mounted in bearings 283 which are set into the ends of the clamping band 80. Each bearing 283 is fitted with a lining 285 of electrically insulating material to prevent any electrical current from flowing between the clamping band 80 and the pull bar 282.

It will be seen that a pair of link bars 287 are welded or otherwise secured to the central portion of the pull bar 282. These link bars 287 are connected to an operating lever 308 which is similar to the lever 108, previously described. However, the lever 308 is positioned horizontally rather than vertically. Thus, the lever 308 is swinga'ble about a pivot 310 mounted on the side plate 7 28 of the body or base 14. The link bars 287 are connected to the lever 308 by means of a pivot 316.

As before, the lever 308 is adapted to be operated by the hydraulic cylinder 120. Thus, the rod or link 124 is connected to the free end of the lever 308.

During normal operation, the electricity is supplied to the contact shoe 240 by the solid arm 257, which provides a connection of extremely low electrical resistance. By means of the pipe 269 and the flexible metal hose 271, the cooling water may be supplied from one bus bar 264 to one end of the contact shoe 240. After passing through the passages 250 in the contact shoe 240, the cooling water is carried from the opposite end of the shoe 240 to one end of the clamping band 80, by the pipe 273 and the flexible metal hose 275. The cooling water passes through the passages 134 in the clamping band and is returned to the other bus bar 264 by the hose 277 and the pipe 279.

Due to ordinary wear, it may occasionally be necessary to replace the contact shoe 240. When this is to be done, the clamping band 80 is loosened, so that the shoe can be disengaged from the electrode. The clamping bolts 268 are then loosened so that the clamping bracket 265 can be removed from the bus bars 264, The hoses and pipes 269-279 are disconnected, and then the shoe 240 can readily be removed from the electrode head 210. A new contact shoe may be mounted on the electrode head.

As before, the lining plates 160 may also be removed and replaced very readily. Thus, the maintenance cost of the electrode head is very low. The contact shoe on the lining plates may be replaced without removing the electrode head from the electrode. Thus, the necessary maintenance operations may be carried out on the electrode head with only a minimum shutdown of the electric furnace.

Various other modifications, alternative constructions, and equivalents may .be employed without departing from the true spirit and scope of the invention, as exemplified in the foregoing description and defined in the following claims.

I claim:

1. An electrode head for use with a generally cylindrical electric furnace electrode or the like,

comprising the combination of a body adapted to be disposed opposite one side port-ion of the electrode,

a cylindrically curved contact shoe removably mounted in a stationary position on said body for engaging the electrode to transmit electric currents thereto,

said contact shoe having inlet and outlet openings therein and a passage therein extending between said :inlet and outlet openings for carrying a fluid coolant,

said contact shoe being made of a metal having high electrical conductivity,

means for supplying electric currents to said shoe,

a generally U-shaped clamping band movably mounted on said body opposite said contact shoe for clamping the electrode against said contact shoe,

said band having inlet and outlet openings therein, and a passage therein extending between said last mentioned openings for carrying the fluid coolant,

conduit means connected to said last mentioned inlet and outlet openings for carrying the fluid coolant to and from said band,

at least one curved lining plate disposed against the inner side of said band and adapted to be clamped between said band and electrode,

mounting means removably securing said lining plate to said band,

said clamping band and said lining plate being made of a metal having a substantially lower electrical conductivity than the metal of said contact shoe,

and a clamping mechanism on said body for pulling said clamping band toward said contact shoe to clamp the electrode therebetween.

2. An electrode head according to claim 1,

including a plurality of such lining plates spaced at angular intervals around the inner side of said clamping band.

3. An electrode head according to claim 1,

in which said mounting means is in the form of clips secured to said lining plate and hooked over said clamping band.

4. An electrode head according to claim 1,

in which said clamping band and said lining plate are made of stainless steel,

said contact shoe being made substantially of copper.

5. An electrode head according to claim 1,

in which said means for supplying electric currents to said shoe comprise electrically conductive tubes connected to said inlet and outlet openings in said shoe,

whereby said tubes are also eflective to circulate the fluid coolant to and from said shoe.

6. An electrode head according to claim 5,

including means for removably connecting said tubes to an electrical supply bus.

7. An electrode head according to claim 1,

in which said means for supplying electric currents to said shoe comprise an electrically conductive member extending from said shoe,

and means for removably connecting said conductive member to an electrical supply bus.

8. An electrode head according to claim 7,

in which said conductive member is formed integrally with said shoe.

9. An electrode head according to claim 7,

including additional conduit means connected to said inlet and outlet openings in said shoe for carrying the fluid coolant to and from said shoe.

10. An electrode head according to claim 1,

in which said means for supplying electric currents to said shoe comprise an electrically conductive member extending from said shoe,

and clamping means for connecting said conductive member to an electrical supply bus.

References Cited UNITED STATES PATENTS 1,335,895 4/1920 Hughes 13-18 2,423,714 7/1947 Leonard 13-16 X 2,632,780 3/1953 Whitehouse 1316 3,026,444 3/1962 Slocombe et al 314-401 3,402,250 9/1968 Turner 1314 X BERNARD A. GILHEANY, Primary Examiner.

H. B. GILSON, Assistant Examiner.

U.S. Cl. X.R. 13-9

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