AU2006225331B2 - Locking Means for Anchors For Castable Refractory Cement - Google Patents

Description

P/00/011 28/5/91 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Pressform Engineering Pty Ltd Actual Inventor John Worner Address for service is: WRAY & ASSOCIATES Level 4, The Quadrant 1 William Street Perth, WA 6000 Attorney code: WR Invention Title: "Lockings Means for Anchors for Castable Refractory Cement" The following statement is a full description of this invention, including the best method of performing it known to me: 1 -2 "Locking Means for Anchors for Castable Refractory Cement" Field of the Invention The present invention relates to a device and a method for locking anchors used to support castable or monolithic refractory cement in a furnace shell. 5 Background Art The interior of furnaces are often lined with castable or monolithic refractory cement. A typical furnace is constructed by first erecting a furnace shell and then applying a layer of refractory cement over the surface of the shell to provide insulation. It is necessary to support the refractory cement during the application 10 of the cement. It is also necessary to continue that support during use of the furnace. Because furnaces are raised to a very high temperature during operation and then cooled again to normal temperatures, the cement undergoes significant expansion and contraction. This causes cracking so that the cement would break away from the furnace shell if it is not adequately supported from 15 the shell during use. One form of anchor for use in such situations is disclosed in GB2289105 however it is believed that this arrangement presents problems because of its complexity and results in the creation of voids within the refractory which is not desirable 20 The applicant has previously developed an anchor which comprises a substantially V shaped anchor supported by a lug secured to the refractory shell. Figure 1 provides a drawing of that anchor. As shown in the drawings, the lug 11 comprises a simple metal plate usually welded to the furnace shell 12 and upstanding from the shell transversely to the surface. The lug 11 is normally 25 formed from mild steel or stainless steel and is provided with a slotted aperture 14 adapted to receive the anchor 21 during installation. The longitudinal axis of the slotted aperture 14 runs generally parallel to the shell surface 12 in the -3 vicinity of the lug 11. The anchor is formed from stainless steel or nickel alloy rod and comprises two opposed arms converging towards each other in a general V configuration which intersect at an apex configured as a 'U' shaped formation 22 rather a simple apex. The arms of the rod are formed with a slight 5 wave formation 23 along their length to provide better adherence to the refractory cement. In addition the thickness of the anchor in the region of the apex is greater in the plane accommodating the arms and is greater than the thickness of the arms. While the width of the slotted aperture is such that the arms of the anchor are snugly received by the aperture and the apex is received by the 10 aperture when the arms are parallel to the wall. The anchor 21 is mounted to the lug by passing one arm through the aperture 14 of the lug 11 with the both of the arms held to be approximately parallel to the wall (25) until the U shaped apex 22 is centred in the aperture 14. The anchor is then caused to rotate about the lug until the anchor extends substantially transversely from the wall and the lug. The 15 rotation of the anchor causes the frictional engagement of the apex of the anchor within the slotted aperture which results in some deformation of the apex and/or the aperture. Due to the curvature and deformation of the rod at the base of the U shaped apex, the U shaped apex is jammed in the aperture of the lug to provide reasonably secure engagement. In general, this engagement has been 20 satisfactory to hold anchors in place until the refractory cement is cast. This arrangement can be successful while the furnace is in use because of its ability to allow movement of the anchor relative to the lug, in a direction substantially parallel to the plane of the shell in the vicinity of the lug to cope with expansion and contraction of the cement and the shell. This has been found to 25 be particularly useful for rotatable furnaces, but is also useful in conventional stationary furnaces. A problem experienced with this style of anchor occurs in maintaining the anchor in position prior to the cement being cast. The anchor requires only a relatively small lateral force to knock it over and once it is dislodged a little it will tend to fall 30 against the shell wall. Because the original lock depends on an interference fit between the surfaces of the U shaped apex and the slotted aperture, when the -4 anchor is first rotated into its transverse position, some compression of the steel occurs at the contact point. This can tend to deform the metal of the lug a little such that any subsequent attempt to rotate an anchor upright is not quite as effective as the initial action. It then becomes easier to knock the anchor out of 5 its transverse position and this can happen even during the casting process of the cement. Where cement is cast with the anchor dislodged from its transverse position, particularly against the furnace shell, the anchor no longer performs its function and therefore the cement in that area is not properly supported. This can lead to premature failure of the cement requiring an expensive maintenance 10 repair and furnace downtime. It has been attempted to prevent the anchor from being dislodged from an transverse position by tack welding the anchor to the lug. The intention being that the weld will be sufficient to hold the anchor during casting of the refractory cement but that the weld will break when the furnace is in use enabling the 15 refractory cement to move relative to the lug. However this method has created further problems. Firstly it is difficult to control the amount of tack welding required. If too much is applied, the tack will not break in use thereby preventing the anchor from moving relative to the lug. This is likely to lead to failure of the anchor and/or the refractory cement in its vicinity. If too little tack weld is applied, 20 the weld will still break prematurely and the original problem will not be overcome. As well, the weld may affect the strength of the anchor and in any event is very time consuming and therefore an expensive process to apply. The discussion throughout this specification, of the background and prior art and to the invention in particular the disclosure in GB2289105 is intended only to 25 facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia and the world as at the priority date of the application.

-5 Disclosure of the Invention Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the 5 exclusion of any other integer or group of integers. According to one aspect the invention resides in a locking means for a refractory anchor which is used to support a refractory lining material from the wall of a furnace and in which the refractory anchor is supported from a support element on the wall, the support element having an aperture, the refractory anchor 10 comprising a pair of divergent arms interconnected at a junction, wherein in use the refractory anchor is to be supported from the support element with the junction received in the aperture and the arms extending outwardly from the wall, the locking means comprising an element adapted to be supported from the support to lie between the arms and to engage with the arms to fix the arms in 15 position relative to the support element, wherein the locking means is capable of being affected by the heat generated by the furnace during use to reduce the relative support provided between the refractory anchor and the support element by the locking means. According to preferred feature of the invention the anchor is formed from a rod 20 like material. According to preferred feature of the invention the support element comprises a lug fixed to the wall of the furnace. According to preferred feature of the invention the lug, has a pair of opposed side edges and an end face in spaced relation from the wall, the locking means 25 configured to engage the support to be supported from the side edges, the locking means having a pair of opposed sides, the spacing between the sides and the configuration of the recesses enabling the recesses to engage the arms when the locking means is supported from the support. According to preferred -6 feature of the invention the sides of the locking means are provided with at least one recess which is configured to receive the respective arm when in position. According to preferred feature of the invention the configuration of the locking means enabling engagement with the side edges comprises a pair of retention 5 means adapted to engage the opposed side edges of the lug. According to one embodiment the retention means comprises a pair end elements interconnecting the sides of the locking means and having a spacing there between corresponding to the width of the lug and having formations on their opposed faces which will engage with the side edges of the lug when the locking means is 10 in position on the lug.. According to another embodiment the retention means comprises a pair of openings which are each configured to be engagable with opposed comers of the lug defined between the end face and the side edges, the openings being positioned relative to each other to be receivable over the opposed comers of the lug when the locking means is in position over the lug 15 According to preferred feature of the invention the locking means is formed of a material which will melt and/or vaporise under the influence of the heat generated by the furnace. According to preferred feature of the invention the locking means is formed of a plastics material. 20 According to preferred feature of the invention the locking means is has an inherent resilience and/or temper which is reduced by the heat generated by the furnace. According to one embodiment the locking means is formed from mild steel which becomes deformable during use of the furnace to permit movement of the anchor relative to the support element during use of the furnace. According 25 to another embodiment the locking means is formed from a spring steel which will lose its temper during use of the furnace due to the heat to permit movement of the anchor relative to the lug during use of the furnace. According to another aspect the invention resides in a method of mounting a refractory anchor to the wall of a furnace, prior to the application of refractory -7 cement to the wall, wherein the refractory anchor comprises a pair of divergent arms interconnected at a junction, the wall having a support element extending from the surface of a portion of the wall and having an aperture the central axis of which is generally parallel to the portion of the wall, the method comprising 5 locating an arm of the refractory anchor in the aperture of the support with the arms of the anchor being substantially parallel to the portion of the wall, inserting the arm into the aperture to locate the junction within the aperture, rotating the anchor such that it extends outwardly from the portion of the wall and locating a locking means between the arms such that it is engaged between the arms and 10 with the support element to fix the arms in position relative to the support element, wherein the locking means is capable of being affected by the heat generated by the fumace during use to reduce the relative support provided between the refractory anchor and the support element by the locking means. The invention will be more fully understood in light of the following description of 15 several specific embodiments. Brief Description of the Drawings The description is made with reference to the accompanying drawings, of which: Figure 1 is an isometric drawing of a refractory anchor installed within a support lug according to the prior art; 20 Figure 2 is an isometric view of a locking clip according to the first embodiment; Figure 3 is an isometric view of the locking clip of Figure 2 showing its orientation to the anchor and lug, immediately prior to installation; Figure 4 is an isometric view of the locking clip of Figure 2 in engagement with the lug and anchor (shown by dotted lines); 25 Figure 5 is an isometric view of a locking clip according to the second embodiment; -8 Figure 6 is an isometric view of the locking clip of Figure 5 showing its orientation to the anchor and lug, immediately prior to installation; and Figure 7 is an isometric view of the locking clip of Figure 5 showing its orientation to the anchor and lug, immediately after installation. 5 Detailed Description of Preferred Embodiments The embodiments of the invention are directed to a locking means for a refractory anchor adapted to prevent rotation of the refractory anchor relative to a support which engagingly supports the anchor prior to and during casting of refractory cement but wherein the locking means will lose its ability to restrain the 10 anchor when the furnace is in use and once the heat of the fumace is applied to the locking means. The first embodiment is described with reference to Figures 2, 3 and 4. The first embodiment as shown in Figures 2 to 4 comprises a locking means in the form of a locking clip 31. The locking clip is adapted to be positioned over a 15 support lug 11 extending from a furnace shell 12 while a refractory anchor 21 is in place in the transverse position relative to the lug 11. The lug 11 comprises a generally rectangular member of mild steel or stainless steel, typically having thickness between 8mm and 25 mm, width of between 30mm and 80 mm and length extending from the shell of 50mm to 120mm. The corners 15 of the 20 intersection of the length and width of the lug remote from the shell 12 are rounded to facilitate the engagement of the locking clip with the lug, as discussed below. Each of the narrow sides of the lug 11 at a position spaced from the from the end face 17 of the lug is provided a transverse notch 18 parallel to the end face 17 of the lug, to provide for engagement by the clip 31 as is described 25 below. An slotted aperture 14 is provided through the lug 11 to receive the anchor 21. The elongate axis of the aperture is substantially parallel to the end face of the lug and the portion of the shell wall in the vicinity of the lug 11. The locking clip 31 according to the first embodiment comprises a metal bracket formed from mild steel sheet, typically of about 1 mm in thickness and having a -9 base section 32 of generally rectangular form comprising a pair of opposed ends 34 and a pair of opposed sides 35 and a pair of arms 33 extending generally transversely to the base section at either end of the base section in opposed relation to each other. . Each side 35 a cut out 36, each cut out 36 being of 5 generally semi-circular form with the diameter of the cut out positioned mid way along the edge of the end 35. The diameter of the cut out is configured to conform to the diameter of the rod from which the anchor 21 is constructed. The cut out provides the recess in the locking clip which in use will receive and support the arms of the anchor. 10 The end members 33 are angularly offset from the base section 32 so that the end members are at an acute angle of approximately 80 degrees relative to the base section, thus the end 33 members are slightly convergent with respect to each other. The corners 37 of the end members 33 away form the base section 32 are bent inwardly, to be substantially parallel with a spacing generally 15 corresponding to the thickness of the lug in order that the bent comers of the end members will loosely engage the lug 11 when the locking clip 31 is placed over the lug 11. A tag 41 of generally rectangular formation is formed in each of the end members 33, typically by stamping or punching a rectangular area within the end member to cause the area to be sheared away from end member, 20 directed inwardly, to form the tag having a tag end 42 and a pair of opposed sides 43. The tag end 42 is proximate the base section 32 while the end of the rectangle opposed to the base section remains connected to the end member 33 to thereby support the tag 41. The distance between the end members 33 corresponds to the width of the 25 lug 11. In use, as shown in Figure 3 and 4, once the anchor is engaged with the support and is positioned to extend outwardly from the wall the locking clip 31 is placed over the lug 11 with the clip 31 oriented so that the cut-outs 36 of the base section ends are engaged with the arms of the anchor 21, the end members 33 of the clip 31 overlie the opposed sides of the lug 11. As the clip 30 31 is pressed home, the tags 41 engage the sides 16, to cause resilient movement of the end members 33 away form each other a little until the tag ends -10 42 engage the notch 18 in the respective side to thereby secure the clip 31 to the lug 11. At this position, the cut-outs 36 of the base section securely engage the anchor 21 to hold it in position relative to the lug and as a result movement of the anchor relative to the lug is restrained. 5 Once the refractory cement has been applied and cured, the use of the furnace will result in the wall and the refractory cement being heated. The resultant slow heating and cooling of the locking clip 31 will cause it to lose its temper and thus the capacity to prevent relative movement of the anchor relative to the lug which will result from the repetitive heating and cooling of the furnace walls.. This loss 10 of temper is sufficient to accommodate for the relative movement between the lug and the clip and the refractory anchor and the surrounding refractory cement that arises from the heating of the walls of the furnace and the resultant differential contraction and expansion between each of the elements. A locking clip according to the second embodiment of the invention is shown in 15 Figures 5 to 7. The locking clip according to a second embodiment functions in substantially the same manner as that of the first embodiment although the configuration differs. As shown in the drawings, the locking clip 51 has a generally U-shaped profile comprising a central base section 52 and two arms 53 which extend divergently from each end of the base section. The base section 20 52 has a configuration similar to that of the first embodiment and so it is not described again and like reference numerals are used in regard to corresponding elements. The arms 53 each comprise planar, substantially rectangular members extending divergently from the sides 34 of the base section. Each of the arms 53 is formed with a rectangular opening 55, the 25 innermost edge 56 of the opening is substantially aligned with the respective side 34 of the base section 52. The length of each opening 55 is a substantial proportion of the length of the respective arm 53 The width of each opening is slightly greater than the thickness of the lug 11. A plurality of small apertures 59 are provided in the arms to enable cement to pass there through when the 30 locking clip is in position .

- 11 In use the locking clip according to the second embodiment is placed over the lug 11 and between the arms of the anchor when in position on the lug in a similar manner to the first embodiment whereby the recesses 36 of the base section 52 receive the arms of the anchor 21. In addition the arms 53 of the 5 clip 51 overlie comers of the lug such the comer is received through the opening 55. As the locking clip 51 is pressed into engagement with the lug 11, the remote edge 60 of the opening 55 of each arm frictionally engages the respective side of the lug, thereby resiliently displacing the arms and the clip will move over the lug until the remote edges 60 engage the notches the respective side of the 10 lug. Because of its resilient nature locking the clip provides a very positive engagement between the locking clip and the lug and thus. a very positive support for the anchor. According to a preferred feature of the second embodiment, the lug is provided with a plurality of notches18 on each side, as shown in Figure 6. The notches 15 are parallel and enable the clip to engage the lug at more than one position along the side According to a further embodiment the series of notches are formed to have a ratchet-like profile where to provide more secure retention of the locking clip with the lug. Once the refractory cement has been applied and cured, the use of the furnace 20 will result in the wall and the refractory cement being heated the resultant slow heating and cooling of the locking clip will cause it to losing the temper which maintains the clip in engagement with the lug 11 and the refractory anchor. This loss of temper is sufficient to accommodate for the relative movement between the lug and the clip and the refractory anchor and the surrounding refractory 25 cement that arises from the heating of the walls of the furnace and the resultant differential contraction and expansion between each of the elements. The locking clip 51 of the of the second embodiment is formed from a spring steel such that the clip resiliently deformable. The locking clip 51 of the second embodiment can be made from material that has a thickness less than that of the 30 first embodiment, and can have a thickness of 0.5mm or less.

-12 According to a further embodiment the locking clips of the first or second embodiment are formed of a resilient plastics material which will lose their resilience and/or melt when heated by the furnace. There are many adaptations possible to the embodiments described which may 5 retain the inventive feature of the device. It should be appreciated that all such adaptations are to be considered within the scope of the invention.

Claims (16)

1. A locking means for a refractory anchor which is used to support a refractory lining material from the wall of a fumace and in which the refractory anchor 5 is supported from a support element on the wall, the support element having an aperture, the refractory anchor comprising a pair of divergent arms interconnected at a junction, wherein in use the refractory anchor is to be supported from the support element with the junction received in the aperture and the arms extending outwardly from the wall, the locking means 10 comprising an element adapted to be supported from the support to lie between the arms and to engage with the arms to fix the arms in position relative to the support element, wherein the locking means is capable of being affected by the heat generated by the furnace during use to reduce the relative support provided between the refractory anchor and the support 15 element by the locking means.

2. A locking means for a refractory anchor as claimed at claim 1 wherein the anchor is formed from a rod-like material.

3. A locking means for a refractory anchor as claimed at claim 1 or 2 wherein the support element comprises a lug fixed to the wall of the furnace. 20

4. A locking means for a refractory anchor as claimed at claim 3 wherein the lug, has a pair of opposed side edges and an end face in spaced relation from the wall, the locking means configured to engage the support to be supported from the side edges, the locking means having a pair of opposed sides, the spacing between the sides and the configuration of the recesses 25 enabling the recesses to engage the arms when the locking means is supported from the support.

5. A locking means for a refractory anchor as claimed at any one Of the preceding claims wherein the sides of the locking means are provided with - 14 at least one recess which is configured to receive the respective arm when in position.

6. A locking means for a refractory anchor as claimed at claim 5 as dependant from claim 4 wherein the configuration of the locking means enabling 5 engagement with the side edges comprises a pair of retention means adapted to engage the opposed side edges of the lug.

7. A locking means for a refractory anchor as claimed at claim 6 wherein the retention means comprise a pair end elements interconnecting the sides of the locking means and having a spacing there between corresponding to the 10 width of the lug and having formations on their opposed faces which will engage with the side edges of the lug when the locking means is in position on the lug..

8. A locking means for a refractory anchor as claimed at claim 6 wherein the retention means comprises a pair of openings which are each configured to 15 be engagable with opposed corners of the lug defined between the end face and the side edges, the openings being positioned relative to each other to be receivable over the opposed corners of the lug when the locking means is in position over the lug

9. A locking means for a refractory anchor as claimed at any one of the 20 preceding claims wherein the locking means is formed of a material which will melt and/or vaporise under the influence of the heat generated by the furnace.

10. A locking means for a refractory anchor as claimed at any one of the receding claims wherein the locking means is formed of a plastics material. 25

11. A locking means for a refractory anchor as claimed at any one of claims 1 to 8 wherein the locking means is has an inherent resilience and/or temper which is reduced by the heat generated by the furnace. - 15

12. A locking means for a refractory anchor as claimed at claim 11 wherein the locking means is formed from mild steel which becomes deformable during use of the furnace to permit movement of the anchor relative to the support element during use of the furnace. 5

13. A locking means for a refractory anchor as claimed at claim 11 wherein the locking means is formed from a spring steel which will lose its temper during use of the furnace due to the heat to permit movement of the anchor relative to the lug during use of the furnace.

14. A locking means for a refractory anchor substantially as herein described 10 with reference to Figures 2 to 7 of the accompanying drawings.

15. A method of mounting a refractory anchor to the wall of a furnace, prior to the application of refractory cement to the wall, wherein the refractory anchor comprises a pair of divergent arms interconnected at a junction, the wall having a support element extending from the surface of a portion of the 15 wall and having an aperture the central axis of which is generally parallel to the portion of the wall, the method comprising locating an arm of the refractory anchor in the aperture of the support with the arms of the anchor being substantially parallel to the portion of the wall, inserting the arm into the aperture to locate the junction within the aperture, rotating the anchor 20 such that it extends outwardly from the portion of the wall and locating a locking means between the arms such that it is engaged between the arms and with the support element to fix the arms in position relative to the support element, wherein the locking means is capable of being affected by the heat generated by the furnace during use to reduce the relative support 25 provided between the refractory anchor and the support element by the locking means.

16. A method of mounting a refractory anchor to the wall of a fumace, prior to the application of refractory cement to the wall substantially as herein described with reference to the specific embodiment of the invention and as 30 shown at Figures 2 to 7 of the accompanying drawings.