US3509261A

US3509261A - Electric furnace electrode head

Info

Publication number: US3509261A
Application number: US781457A
Authority: US
Inventors: Donald L Phillips
Original assignee: DIXIE BRONZE Co
Current assignee: DIXIE BRONZE Co
Priority date: 1968-12-05
Filing date: 1968-12-05
Publication date: 1970-04-28
Anticipated expiration: 1987-04-28

Description

` April` 2s, A19m Filed Dec. s, 1968 Dsl., PHILLIPS ELECTRIC FURNACE ELEGTRODE HEAD'.

2 Sheets--Sheet 2 United States Patent O ABSTRACT F THE DISCLOSURE The electrode head comprises a U-shaped contact band and a curved contact shoe, both of which are employed to conduct the electrical current to the electrode. Both are made of copper or other highly conductive material and areformed with internal passages for carrying cooling water or the like. The contact band comprises inner and outer walls with partitions welded therebetween to form a sinuous water passage. A lever mechanism is provided to apply clamping pressure between the shoe and the band. The lever is connected by means of a link and a swivel bar to the ends of the band. The electrical current and the water are supplied by bus tubes. Downcomer tubes are connected between the bus tubes and the inlet and outlet openings on the band and the shoe to supply the electrical current thereto, while also circulating the water therethrough.

This invention relates to electrode heads for supplying electrical current to electrodes of the type employed in electric arc furnaces. Such electrode heads are subjected to extremely high temperatures and electric current densities. From time to time, it is necessary to shift the electrode relative to the head, because the electrode is gradually consumed. Thus, it must be possible to loosen the engagement between the electrode head and the electrode. During normal operation, however, such engagement must be extremely secure, to avoid any possibility of arcing or slippage between the electrode head and the electrode. Problems have been encountered in the prior art with such arcing, and also with overheating of the electrode head, and excessive contact resistance between the electrode head and the electrode.

One object of the present invention is to provide an electrode head in which the area of contact with the electrode is greatly increased, without any substantial increase in the overall size of the electrode head, so that the contact resistance between the head and the electrode is reduced. Thus, the current carrying capacity of the electrode head is increased.

Generally speaking, the present invention comprises a U-shaped contact band and a curved contact shoe, adapted to engage the electrode. Means are provided to exert a clamping pressure between the band and the shoe. Preferably, the clamping action is achieved by exerting a pull on the ends of the U-shaped contact band, relative tothe shoe. Both the contactl band and the contact shoe are made of a highly conductive material, such as copper, to provide a low electrical resistance. Both the band and the shoe are formed Awith internal passages to carry cooling water or some other coolant. A plurality of partitions or dividers are preferably provided in both the band and the shoe so that the passages will be sinuous in shape. Inlet and outlet tubes made of copper or some other highly conductive material are connected to both the band and the shoe to circulate the cooling water therethrough, while also carrying the electrical current thereto. The tubes are connected to inlet and outlet openings in the band and the shoe. The tubes extend to a contact head, to which the tubes are clamped or otherwise secured. The contact head comprises means for connecting the contact head to a pair of bus tubes which supply the electrical current, while also carrying the cooling water. Conduit connections are provided to carry the cooling water between the bus tubes and the inlet and outlet tubes so that the water will be circulated through the band and the shoe.

Various other objects, advantages and features of the present invention will appear from the following description, taken with the accompanying drawings, in Iwhich:

FIG. 1 is a plan view of an electrode head to be described as an illustrative embodiment of the present invention.

FIG. 2 is an elevational view, partly in section.

FIG. 3 is an elevational section, taken generally along the line 3-3 in FIG. 1.

FIGS. 4 and 5 are fragmentary sections, taken generally along the lines 4-4 and 5 5 in FIG. 1.

It will be seen that FIGS. 1-5 illustrate an electrode head 10 which is adapted to be connected to a cylindrical electrode 12 of the type employed in 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 electrical current to the electrode 12, and also to provide at least some of the support for the electrode. Typically, the electrode 12 is made of carbon, either with or without a cylindrical sheath of metal. In many instances, the electrode 12 and the electrode head 10 are quite large. Electrode sizes in the range from l2 inches to 48 inches in diameter are quite common. It will be evident that the weight of such electrodes is 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, adapted to be mounted on the outer end of a mast arm or boom 16, illustrated as being cylindrical in shape. A flange 18 is welded or otherwise secured to the outer end of the arm 16. The body 14 is also provided with a mounting flange 20, adapted to be secured to the ange 18 by a plurality of bolts 22 or the like.

A curved contact shoe 24 is mounted in a stationary position on the body 14. The shoe 24 has a cylindrically curved contact surface 26 =which is adapted to engage the electrode 12. To provide low electrical resistance, the shoe 24 is preferably made of a highly conductive material, such as copper or the like.

As shown to best advantage in FIG. 4, the body 14 i preferably comprises a shelf 28 which supports the lower end of the contact shoe 24. The body 14 also preferably comprises a curved vertical plate 30 which backs up the shoe 24. It will be seen that the shoe 24 is formed with an overhanging flange 32 which extends over the curved plate The contact shoe 24 is preferably formed with a sinuous internal passage 34 so that cooling water or some other coolant may be circulated through the shoe. In this way, the shoe 24 is protected against damage due to the high operating temperature of the electrode 12. Moreover, the heat generated in the contact shoe 24 by the passage of the electrical current is effectively carried away.

To form the sinuous passage 34, the shoe 24 may be of the construction disclosed and claimed in the Turner Patent No. 2,997,511, patented Aug. 22, 1961. Thus, it will be seen that the shoe 24 comprises a casting or body 36 formed with alternating channels 38 and dividers or partitions 40. The channels 38 are closed by a curved plate 42, set into a recess 44 in the body 36. The plate 42 is preferably welded to the body 36, as indicated by the welds 46 in FIG. 4. The channels 38 are interconnected to form the sinuous passage 34.

The ends of the sinuous passage 34 are brought out to

openings

48 and 50 in the shoe 24. Either of the openings may serve as the inlet, while the other serves as an outlet for the cooling lwater.

The illustrated electrode head comprises a U-shaped contact band 52, adapted to engage the electrode 12. The electrical current is supplied to the electrode 12 by both the contact shoe 24 and the contact band 52. Thus, the band 52 is also made of a highly conductive material, such as copper or the like. Due to the provision of the contact shoe 24 and the contact band 52, an extremely great area of contact with the electrode 12 is achieved.

A clamping force is exerted between the U-shaped contact band 52 and the curved shoe 24. In this case, the U- shaped band 52 is movably mounted on the body 14. Thus, as shown in FIG. 5, the band 52 is slidable along horizontal supports 54 on the body 14 and is confined between vertical guide plates 56.

It is preferred to develop the clamping pressure be tween the contact shoe 24 and the contact band 52 by exerting a pull on the band 52 relative to the shoe 24. For this purpose the illustrated electrode head 10 is provided with a lever 58 which is swingable about a pivot 60, supported by the body 14. A link 62 is connected to the lever 58 by a pivot pin 64. The link 62 is connected to the central portion of a bar 66 which extends outwardly through openings 68 in the opposite end portions of the U-shaped band 52. The bar 66 is slidably received in the openings 68. The ends of the bar 66 are fitted with retaining bolts 70. When force is exerted on the lever 58, the force is transmitted to the band 52 by means of the link 62 and the bar 66. The lever 58 may be connected to any suitable mechanism for providing the required force which may be developed by springs, hydraulic or air cylinders, or the like. As shown, rods 72 are connected to the lever 58 by a clevis 74 and a pivot pin 76. The rods 72 may be employed to connect the lever 58 to the operating mechanism. The clevis 74 incorporates an insulating joint 78 to prevent any flow of the electrical current along the rods 72.

A sinuous passage 80 is provided in the contact band 52 so that cooling water or some other coolant may be circulated through the band. As shown, the band 52 comprises inner and outer walls 82 and 84, between which the passage 80 is formed. The walls 82 and 84 may be in the form of heavy strips of copper or the like. The simuous passage 80 is formed by a series of spaced dividers or

partitions

86, 88, 90 and 92 Welded or otherwise secured between the inner and outer walls 82 and 84. The

partitions

86 and 92 form the upper and lower walls of the band 52, while the

partitions

88 and 90 act as intermediate dividers. The partitions 86-92 are preferably made of copper or the like. The ends of the sinuous passage 80 are brought out to

openings

94 and 96 in the contact band 52. One of the openings may serve as the inlet, while theother serves as the outlet for the cooling water.

Means are provided to supply the electrical current to the contact shoe 24 and the contact band 52. As shown, such means comprise downcomer tubes 98 and 100, connected to the shoe 24, and

additional tubes

102 and 104, connected to the band 52. The tubes 98 and 100 are connected to the

openings

48 and 50 in the shoe 24. Similarly, the

tubes

102 and 104 are connected to the

openings

94 and 96 in the band 52. Thus, the tubes 98-104 are ernployed to carry both the cooling water and the electricity to the shoe 24 and the band 52. To provide low resistance, the tubes 98-104 are preferably made of a highly conductive material, such as copper or the like. The

tubes

102 and 104 provide sufficient exibility to allow for the clamping movement of the U-shaped band 52.

Means are provided to connect the tubes 98-104 to a pair of

electrical bus tubes

106 and 108 which bring the electrical current to the electrode head 10. The cooling water is also circulated through the

bus tubes

106 and 108. Preferably, the

tubes

106 and 108 are made of copper or some other highly conductive material. In the illustrated construction, a junction or contact head 110 is provided to connect the tubes 98-104 to the

Ibus tubes

106 and 108. The illustrated junction head 110 comprises a body 112 to which the tubes 98-104 are clamped by a clamping plate 114. Bolts 116 or the like are employed to secure the clamping plate 114 to the body 112. It will be seen that semicircular channels 118 are formed in the body 112 to receive the tubes 98-104. Corresponding semicircular channels 120 are formed in the clamping plate 114.

Similarly, the

bus tubes

106 and 108 are secured to the body 112 by means of a clamping plate 122.

Semicircular channels

124 and 126 are formed in the body 112 and the clamping plate 122 to receive the tubes 106 and 10;8. The clamping plate 122 is secured to the body 112 by means of bolts 128.

To provide low resistance, the body 112 and the clamping

plates

114 and 122 are preferably made of a highly conductive material, such as copper or the like. Electrical current flows through the junction head 110 between the bus tubes 106 and the downcomer tubes 98-104.

Additional tubes or conduits are provided to circulate the cooling water. Thus, a conduit 130 is connected between the bus tube 108 and the downcomer tube 102 which leads to the contact band 52. The tube 104, turning from the contact band 52, is connected to the tube by a conduit 132. It will be recalled that the conduit 100 leads to the contact shoe 24. The returning conduit 98 is connected to the bus tube 106 by a conduit 134. It will be understood that the

conduits

130, 132 and 134 comprise various pipes, tubes and fittings, as will be evident from FIGS. 1-3.

During normal operation, the U-shaped contact band 52 and the curved contact shoe 24 are tightly clamped against the cylindrical electrode 12. The electrical current is carried to the electrode by both the U-shaped band 52 and the curved shoe 24. Thus, the area of contact extends for almost the entire circumference of the electrode. There are only very small gaps between the U-shaped band 52 and the ends of the curved shoe 24. Accordingly, the electrode head provides extremely low contact resistance between the electrode head and the electrode. Moreover, the current carrying capacity of the electrode head is extremely high.

The junction head and the downcomer tubes 98 104 carry the electrical current between the

bus tubes

106 and 108 and the curved shoe 24 and the U-shaped band 52. The downcomer tubes 98-104 also supply the cooling water to the shoe 24 and the band 52. The

conduits

130, 132 and 134 provide the connections whereby the cooling water is supplied by one of the

bus tubes

106 and 108, is circulated through the shoe 24 and the band 52, and is carried away by the other bus tube. One direction of water circulation is indicated by arrows in FIGS. 1-3, but the water can also be circulated in the opposite direction.

Exceptionally efficient cooling of the electrode head 10 is provided by the water cooled shoe 24 and the water cooled band 52. Thus, the electrode head is capable of carrying a high current while operating at a low temperature. Both the shoe 24 and the band 52 are made of copper or the like, which provides very good heat conductivity, while also providing extremely low electrical resistance.

Various other modifications, alternative constructions and equivalents may be employed, as will be understood bythose skilled in the art.

I claim:

1. An electrode head for receiving an electric furnace electrode or the like,

comprising the combination of a generally U-shaped contact band for engaging the electrode,

a curved contact shoe opposite said band for engaging the electrode,

means for exerting a clamping force between said band and said shoe,

said band and said shoe being made of a material having high electrical conductivity,

said band and said shoe having coolant passages therein to provide for the circulation of a coolant through said band and said shoe,

electrically conductive elements for carrying electric currents to both said band and said shoe to energize the electrode, a body, said shoe being mounted on said body in a stationary position relative thereto, said band being movably mounted on said body, and actuating means for exerting a pull on said contact band to produce the clamping force between said band and said shoe, said actuating means comprising a lever, and a linkage connected between said lever and the. end portions of said contact band.

2. An electrode head according to claim 1,

in which said electrically conductive elements cornprise electrically conductive tubes connected to said band and said shoe.

3. An electrode head according to claim 1,

in which said coolant passages are brought out yto inlet and outlet openings in said band and said shoe,

said electrically conductive elements comprising tubes connected to said inlet and outlet openings for carrying the coolant as well as the electrical currents to said band and said shoe.

4. An electrode head according to claim 3,

including an electrically conductive junction head connected between said tubes for distributing the electrical currents thereto,

said tubes extending between 'said junction head and said band and said shoe.

5. An electrode head according to claim 4,

including conduits interconnecting said tubes and forming a complete circulatory system for the coolant.

6. An electrode head according to claim 1,

in which said coolant passages are brought out to inlet and outlet openings in said band and said shoe,

tubes being connected to said inlet and outlet openings for circulating the coolant through said band and said shoe.

7. An electrode head according to claim 6,

including conduits interconnecting said tubes to for a complete circulatory system for the coolant.

8. An electrode head according to claim 1,

in which said contact band comprises inner and outer walls with dividers extending therebetween to form the coolant passage in said band.

9. An electrode head according to claim 1,

in which said contact shoe comprises inner and outer members having openings therebetween forming said coolant passage in said shoe.

10. An electrode head according to claim 1,

in which said linkage comprises a bar connected between the end portions of said contact band, said linkage also comprising a link connected between said lever and said bar.

11. An electrode head according to claim 1,

in which ysaid coolant passages are brought out to inlet and outlet openings in said band and said shoe,

said electrically conductive elements comprising electrically conductive tubes connected to said inlet and outlet openings for carrying the coolant as well as the electrical currents to said band and said shoe,

said electrically conductive elements comprising a junction head connected t0 Said tubes and forming an electrical terminal,

said junction head having clamping means for securing said tubes to said junction head,

said junction head having additional clamping means for connecting said junction head to electrical bus conductors or the like.

12. An electrode head according to claim 11,

including con-duits connected between Said tubes and forming a complete circulatory system for the coolant.

References Cited UNITED STATES PATENTS 2,249,776 7/ 1941 Moore 13-16 2,668,183 2/1954 Foyn 13--16 2,700,692 l/1955 Carleton 13-16 2,982,804 5/1961 Reschke 13-16 3,026,444 3/1962 Slocombe et al 13-l6 X 3,293,402 12/1966 Graham 13-16 3,444,305 5/1969 Turner 13-16 2,386,260 10/ 1945 Payne 13-16 3,402,250 9/1968 Turner 13-16 HlRAM B. GILSON, Primary Examiner U.S. Cl. X.R.