Pressure ring assembly, pressure ring sections and wedge-shaped connector between pressure ring sections

Abstract

The invention relates to a pressure ring assembly, a pressure ring section and a wedge connector between pressure ring sections. The pressure ring assembly (10) includes at least a first section (12.1) and a second section (12.2) connected to each other in an abutting relationship by a removable wedge connector (14) including a first fork (36) and a second fork (38). Each section comprises a body (20) extending in an arcuate manner between a first side wall (22) and a second side wall (24) thereof. Each section defines a first elongated aperture (26) and a second elongated aperture (28). Each hole has a rounded wall section (30) facing the adjacent side wall with a radius of at least 15 mm. The first fork and the second fork are separated from each other at an angle less than 15 degrees. The first fork extends into the second bore of the first section and the second fork extends into the first bore of the second section. The mutually facing contact surfaces (46, 48) of the first and second forks have a contour complementary to the rounded wall section (30) of the bore.

Description

TECHNICAL FIELD

[0001] The present invention relates to an electro-metallurgical furnace and more specifically to a pressure ring segment, a wedge connector and a pressure ring assembly for an electrode of such a furnace. BACKGROUND

[0002] In an electric furnace it is common practice to have a pressure ring assembly for three main purposes. First, the pressure ring assembly forms a ring around the electrical contact pads or shoes, to which typically a hydraulic pressure is applied, which forces the shoes against the electrode to ensure good electrical contact. The counter force is then absorbed by the pressure ring assembly. Second, the pressure ring is needed to protect the hydraulic cylinders for activating the contact shoes and the pipes for cooling fluid from the harsh furnace environment. Third, in some furnaces the pressure ring assembly serves as a cylindrical sleeve and anchoring point for a heat shield around the electrode and a sealing assembly acts on it to isolate the furnace environment from the atmosphere around the furnace.

[0003] Hence, these three main purposes require the pressure ring to be a solid circular sleeve assembly with significant strength to withstand the hydraulic pressure and particularly heat resistant in order to withstand the extremely high temperatures during operation.

[0004] It is for this reason that a high thermal conductive material, such as copper, is particularly advantageous, as it can be easily cooled by means of a forced water flow. A lower thermal conductive material, such as aluminium bronze or stainless steel, can also be used, but less successfully, as the thermal stresses in for example an electric melting furnace typically cause the lower thermal conductive material to fail faster than the copper in a copper / silver alloy.

[0005] However, copper has a relatively low strength and also creeps over time without careful management of the stresses.

[0006] A further requirement of the pressure ring is that it needs to be serviced within as short a time period as possible. Components fail for various reasons and in such a case the maintenance personnel need to be able to open the pressure ring with as little effort as possible, service the failed component, such as a contact shoe or a pipe, and close the pressure ring as quickly as possible to resume production.

[0007] To this end it is highly advantageous to use a tapered wedge or an inverted wedge as disclosed in the applicant's WO / 2005071335A2, as the only tools needed are a crowbar to release the wedge and a sledge hammer to hammer the wedge back into place.

[0008] However, in some applications where there are periodic intervals of extreme heat from the plasma jet, it can be advantageous to have a pressure ring with more weight than the pressure ring of WO 2005 / 071335, as the shear block of copper can absorb a large amount of heat energy and will transfer the heat efficiently to the internal water channels for removal of heat, thereby keeping the copper relatively cool and not affected by the extreme heat. To add this additional volume, the clamping mechanism of WO 2005 / 071335 comprising the wedge connectors between the peripherally mounted segments can not be ideal, as it requires removal of a large portion of the pressure ring segment body material for the fitting, positioning and functioning of the connectors. SUMMARY

[0009] It is therefore an object of the present invention to provide a pressure ring assembly, a pressure ring segment and a wedge connector for adjacent pressure ring segments, with which the applicant believes that at least the above-mentioned drawbacks can be mitigated or a useful alternative to known pressure ring assemblies, pressure ring segments and wedge connectors can be provided.

[0010] According to the invention, there is provided a pressure ring assembly having a central Cr and comprising at least a first pressure ring segment and a second pressure ring segment connected to each other in abutting relationship by a removable wedge connector, wherein

[0011] - each segment:

[0012] o comprises a body extending arcuately between opposite first and second side walls of each segment, the first and second side walls extending between a top wall and a bottom wall,

[0013] o defines a first and a second elongated hole adjacent to the first and second side walls respectively, each hole being inclined away from the adjacent side wall in a direction towards the bottom wall and having a rounded wall section facing the adjacent side wall, the wall section having a radius of curvature R and a centre of curvature on a line Cr tangent to an imaginary circle I with centre T , the wall section being symmetrical about the line Cc ; T

[0014] o defines a first elongated slit in the first side wall extending from the top wall towards the bottom wall and communicating with the first hole and a second elongated slit in the second side wall extending from the top wall towards the bottom wall and communicating with the second hole

[0015] ;

[0016] - the wedge connector comprises:

[0017] ​○ The first forked portion and the second forked portion are separated from each other at an angle α toward the free ends of the first forked portion and the free ends of the second forked portion.

[0018] ○ At least one web structure, the at least one web structure being located at the first forked portion and the second forked portion

[0019] The extension between the parts; and

[0020] ○ The mutually facing contact surfaces on the forked portion form the rounded wall section of the joint hole.

[0021] The component is configured such that: a first forked portion extends into a second hole in a first section; a second forked portion extends into a first hole in a second section; at least one web structure extends through a second slit in the first section and a first slit in the second section; and the mutually facing contact surfaces of the first and second forked portions abut against a rounded wall section, thereby mechanically fixing the first and second pressure ring sections in a side-by-side configuration, wherein a first sidewall of the second section abuts against a second sidewall of the first section.

[0022] The mutually facing contact surfaces on the forked portion can be shaped to complement the rounded wall section of the hole.

[0023] radius of curvature R It can be greater than 15mm, alternatively greater than 40mm, and further alternatively greater than 70mm.

[0024] The body of each segment may include a thickness dimension. d Separated inner and outer surfaces.

[0025] In some implementations, the radius of curvature R It can be greater than 30% of the thickness dimension. In other embodiments, the radius of curvature... R It can be greater than 50% of the thickness dimension.

[0026] Angle α can be less than 15 degrees. Typically, angle α is between 9 and 13 degrees. In a preferred embodiment, angle α is 12 degrees.

[0027] The invention also includes a pressure ring section comprising a body extending arcuately between opposing first and second sidewalls, the first and second sidewalls extending between a top wall and a bottom wall. The pressure ring section defines a first elongated hole and a second elongated hole adjacent to the first and second sidewalls, respectively. Each hole is inclined away from the adjacent sidewall in a direction toward the bottom wall and has a rounded wall segment facing the adjacent sidewall, the wall segment having a radius of curvature. R and center of curvature CcThe wall section defines a first elongate slit in the first side wall extending from the top wall towards the bottom wall and communicating with the first aperture and a second elongate slit in the second side wall extending from the top wall towards the bottom wall and communicating with the second aperture.

[0028] In a presently preferred embodiment, the centre of curvature of the rounded wall section Cc may be located on the side of the rounded wall section opposite said adjacent side wall. In other embodiments, the centre of curvature Cc may be located on the side of the rounded wall section same as said adjacent side wall.

[0029] The body can be made of at least one of copper, a copper alloy comprising at least 98% copper, a copper and silver alloy, aluminium bronze and stainless steel.

[0030] It is further included within the scope of the invention a wedge connector between pressure ring segments, the wedge connector comprising: a head portion; first and second prong portions extending away from the head portion in diverging relation at an angle a relative to each other towards free ends of the first and second prong portions; at least one web structure extending between the first and second prong portions; and mutually facing curved contact surfaces on the prong portions, the contact surfaces being rounded with a radius of curvature and a centre of curvature.

[0031] The centre of curvature of the curved contact surface of the first prong portion can be on the side of said curved surface opposite the second prong portion.

[0032] The radius of curvature R may be greater than 15 mm, alternatively greater than 40 mm, further alternatively greater than 70 mm.

[0033] The at least one web structure can extend transversely centrally between the first and second prong portions, such that each prong portion provides a first and a second elongate contact surface portion symmetrically relative to the at least one web structure.

[0034] The head portion, the first and second prong portions and the at least one web structure can be integrally formed.

[0035] The wedge connector can be formed of a non-magnetic material. BRIEF DESCRIPTION OF DRAWINGS

[0036] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0037] Figure 1This is a schematic perspective view of the first pressure ring section and the relevant portion of the second pressure ring section (shown in solid lines) of the pressure ring assembly surrounding the electrode (shown in dashed lines) of the electrometallurgical furnace (shown in dashed lines in some parts).

[0038] Figure 2 This is a plan view of the first pressure ring section and the second pressure ring section;

[0039] Figure 3 It is about Figure 2 The cross section of line III-III' in the middle;

[0040] Figure 4 This is a front view of the first pressure ring section and the second pressure ring section;

[0041] Figure 5 It is about Figure 4 The cross section of line V-V' in the middle;

[0042] Figure 6 It is a perspective view of a wedge connector used to connect the first section and the second section in an abutting relationship;

[0043] Figure 7 This is a front view of the wedge connector; and

[0044] Figure 8 about Figure 7 The cross section of line VIII-VIII in the middle. Detailed Implementation

[0045] exist Figure 1 , Figure 2 and Figure 4 In the figure, an example embodiment of the pressure ring assembly for electrode 11 used in an electrometallurgical furnace (not shown) is generally indicated by reference numeral 10.

[0046] Reference Figure 1 The pressure ring assembly 10 has a center Cr It includes at least a first pressure ring segment 12.1 and a second pressure ring segment 12.2 connected to each other in an abutting relationship via a removable wedge connector 14. Each segment includes a body 16 extending arcuately between its opposite first sidewall 18 and second sidewall 20. The sidewalls extend between a top wall 22 and a bottom wall 24. Each segment defines a first elongated hole 26 and a second elongated hole 28 adjacent to the first sidewall 18 and the second sidewall 20, respectively. Each hole is inclined away from the adjacent sidewall in a direction toward the bottom wall. Figure 5 As best shown, each hole has a rounded wall section 30 facing the adjacent sidewall. Figure 1 As shown, the wall segment 30 has a radius of curvature. R and in with Crimaginary circle centered on I tangential lines T center of curvature on Cc . wall section 30 is symmetrical about the line T .

[0047] Each section 12.1, 12.2 further defines a first slit 32 in the first side wall 18 extending from the top wall towards the bottom wall and communicating with the first aperture 26 and a second slit 34 in the second side wall extending from the top wall towards the bottom wall and communicating with the second aperture 28.

[0048] The wedge connector 14 comprises a first prong 36 and a second prong 38 which are separated from each other at an angle a towards its free end 40. At least one web 42 extends between the first prong and the second prong. The wedge further comprises mutually facing surfaces 46, 48 on the prongs which are shaped complementary to the rounded wall section 30 of the apertures 26, 28.

[0049] The pressure ring assembly 10 is configured such that the first prong 36 extends into the second aperture 28 of the first section 12.1, the second prong 38 extends into the first aperture 26 of the second section 12.2, the at least one web structure 42 extends through the second slit 34 of the first section and the first slit 32 of the second section, and the mutually facing contact surfaces 46, 48 of the first and second prongs abut the rounded wall section 30, thereby mechanically fixing the first pressure ring section 12.1 and the second pressure ring section 12.2 in a side-by-side configuration, wherein the first side wall 18 of the second section 12.2 is in abutting contact with the second side wall 20 of the first section 12.1.

[0050] The pressure ring sections are similar in shape and configuration and therefore only reference will be made to the pressure ring sections 12.1 and 12.2 in the following. The top wall 22 and the bottom wall 24 preferably extend parallel to each other. The first side wall 18 and the second side wall 20 extend between the top wall 22 and the bottom wall 24. The body of each pressure ring section further comprises an inner curved surface 50 and an outer surface 52 (best shown in Figure 2 , Figure 4 and Figure 5 ). Preferably, the outer surface 52 is curved as well and extends coaxially with the inner surface 50.

[0051] The first aperture 26 and the second aperture 28 are each inclined at an angle a / 2 away from their respective immediately adjacent side wall 18, 20 in a direction from the top wall 22 towards the bottom wall 24.

[0052] The angle a can be less than 15 degrees. Typically, the angle a is between 9 and 13 degrees. In a preferred embodiment, the angle a is 12 degrees.

[0053] The body can be made of at least one of copper, a copper alloy comprising at least 98% copper, a copper and silver alloy, aluminum bronze, and stainless steel.

[0054] The radius of curvature of the curved wall section 30 R is at least 15 mm, alternatively greater than 40 mm and even greater than 70 mm. As Figure 1 shown in Fig. 1, the center of curvature of the curved wall section 30 of the hole 28 Cc is preferably located on the side of the curved wall section 30 opposite the immediately adjacent side wall 20.

[0055] In Figures 6 to 8 Fig. 2, the removable wedge-shaped connector 14 is shown in more detail. The connector comprises a head 60 and a first elongated prong 36 and a second elongated prong 38 which are separated from each other at an angle a in a direction from the head 60 towards the free end 40. The mutually facing contact surfaces 46, 48 of the first and second prongs have a rounded profile which is complementary to the rounded wall section 30 of the holes 26, 28. At least one web structure 42 extends between the first and second prongs intermediate the head 60 and the free end 40. The at least one web structure 42 extends laterally and centrally between the first 36 and second 38 prongs such that, as shown in Figure 8 Fig. 2, the prong 36 provides a first elongated contact surface portion 46.1 and a second elongated contact surface portion 46.2 which are symmetrical with respect to the at least one web structure and the prong 38 provides similar first and second curved elongated contact surface portions (not clearly shown) which are symmetrical with respect to the at least one web structure. As shown in Figure 8 Fig. 2, the curved contact surfaces 46, 48 have a radius of curvature R and a center of curvature on the side of the surfaces 46, 48 opposite the other prong 38, 36 Ccf .

[0056] In an example embodiment, the head 60, prongs 36, 38 and web structure 42 are integrally formed from a non-magnetic steel material.

[0057] The present invention retains the benefit of the quick and simple assembly and disassembly characteristics of known pressure ring assemblies, thereby enabling efficient maintenance and reduced furnace downtime. In addition, the design optimizes structural performance by evenly distributing the clamping force across the abutting pressure ring segments. This is achieved through the interaction between the rounded wall section 30 of the holes 26, 28 and the complementary curved contact surfaces 46, 48 of the wedge-shaped prongs, which accommodates slight misalignments while limiting the development of undesirable bending moments.

[0058] The contact faces 46, 48 of the wedge-shaped prongs are formed with a relatively large radius of curvature, preferably at least 15 mm, more preferably greater than 30 mm, and in some embodiments, in excess of 70 mm. Smaller radii can result in highly concentrated contact forces and unfavorable load angles. For example, if a prong 36, typically having a diameter of less than 30 mm, engages a hole with a small radius wall section, it can exert excessive outward pressure on the middle copper lug 62 (see Figure 1 and Figure 5 ) potentially resulting in deformation or mechanical failure.

[0059] In contrast, the present invention enhances durability by spreading the contact area between the wedge-shaped prongs and the hole wall section, thereby reducing stress concentration. Furthermore, since the wedge-shaped connector engages internally within the angled hole, rather than via externally mounted peripheral features as in WO 2005 / 071335, the amount of material that must be machined away from the pressure ring section is significantly reduced. This preserves thermal mass and structural integrity, particularly when using high thermal conductivity materials such as copper or copper alloys.

Claims

1. A pressure ring assembly, the pressure ring assembly having a center Cr And includes at least a first pressure ring segment and a second pressure ring segment connected to each other in an abutting relationship via a removable wedge connector, wherein, Each section: Includes a body that extends arcuately between opposite first and second sidewalls in each segment, the first and second sidewalls extending between a top wall and a bottom wall; Defined as a first elongated hole and a second elongated hole adjacent to the first sidewall and the second sidewall respectively, each hole being inclined away from the adjacent sidewall in the direction toward the bottom wall and having a rounded wall segment facing the adjacent sidewall, the wall segment having a radius of curvature ( R ) and in relation to Cr An imaginary circle centered on ( I Tangent lines T The center of curvature on ) Cc The wall segment about the line ( T )symmetry; A first elongated slit extending from the top wall toward the bottom wall and communicating with the first hole in the first sidewall, and a second elongated slit extending from the top wall toward the bottom wall and communicating with the second hole in the second sidewall; The wedge connector includes: The first forked portion and the second forked portion are separated from each other at an angle (α) toward the free ends of the first forked portion and the free ends of the second forked portion. At least one web structure extending between the first forked portion and the second forked portion; and The mutually facing contact surfaces on the forked portion are configured as the rounded wall segments of the engagement hole. The component is configured such that: the first forked portion extends into the second hole of the first section; the second forked portion extends into the first hole of the second section; the at least one web structure extends through the second slit of the first section and the first slit of the second section; and the mutually facing contact surfaces of the first forked portion and the second forked portion abut against the rounded wall section, thereby mechanically fixing the first pressure ring section and the second pressure ring section in a side-by-side configuration.

2. The pressure ring assembly according to claim 1, wherein, The mutually facing contact surfaces on the forked portion are shaped to complement the rounded wall segment of the hole.

3. The pressure ring assembly according to any one of claims 1 and 2, wherein, The radius of curvature ( R The diameter is at least 15 mm, preferably at least 40 mm, and more preferably at least 70 mm.

4. The pressure ring assembly according to any one of claims 1 to 3, wherein, The angle (α) is less than 15 degrees.

5. The pressure ring assembly according to any one of claims 1 to 4, wherein, The center of curvature of the rounded wall segment ( Cc It is located on the side opposite to the adjacent sidewall of the rounded wall segment.

6. The pressure ring assembly according to any one of claims 1 to 5, wherein, The body of each segment comprises a thickness dimension ( d The inner and outer surfaces are separated.

7. The pressure ring assembly according to claim 6, wherein, The radius of curvature ( R ) is greater than the thickness dimension ( d 50% of ).

8. A pressure ring section comprising a body extending arcuately between opposite first and second sidewalls of the pressure ring section, the first and second sidewalls extending between a top and a bottom wall, the pressure ring section defining a first elongated hole and a second elongated hole adjacent to the first and second sidewalls, respectively, each hole being inclined away from the adjacent sidewall in a direction toward the bottom wall and having a rounded wall segment facing the adjacent sidewall, the wall segment having a radius of curvature ( ). R ) and center of curvature ( Cc ), and defined in the first sidewall a first elongated slit extending from the top wall toward the bottom wall and communicating with the first hole, and in the second sidewall a second elongated slit extending from the top wall toward the bottom wall and communicating with the second hole.

9. The pressure ring section according to claim 8, wherein, The center of curvature of the rounded wall segment ( Cc It is located on the side opposite to the adjacent sidewall of the rounded wall segment.

10. The pressure ring section according to any one of claims 8 and 9, wherein, The body is made of at least one of copper, a copper alloy comprising at least 98% copper, a copper and silver alloy, aluminum bronze, and stainless steel.

11. A wedge connector between pressure ring sections, the wedge connector comprising: head; The first forked portion and the second forked portion extend away from the head toward the free ends of the first forked portion and the free ends of the second forked portion in a relationship that is separated from each other at an angle (α); At least one web structure extending between the first forked portion and the second forked portion; and mutually facing curved contact surfaces on the forked portions, the contact surfaces being rounded to have a radius of curvature ( R ) and center of curvature ( Ccf ).

12. The wedge connector according to claim 11, wherein, The center of curvature of the contact surface of the first forked portion ( Ccf On the side of the curved contact surface opposite to the second forked portion.

13. The wedge connector according to any one of claims 11 and 12, wherein, The at least one web structure extends laterally in a central manner between the first forked portion and the second forked portion, such that each forked portion provides a first elongated contact surface portion and a second elongated contact surface portion that are symmetrical with respect to the at least one web structure.

14. The wedge connector according to any one of claims 11 to 13, wherein, The head, the first forked portion, the second forked portion, and the at least one web structure are integrally formed.

15. The wedge connector according to any one of claims 12 to 14, wherein the wedge connector is made of a non-magnetic steel material.

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