GB2159598A - Centering anchor arrangement for high temperature controls - Google Patents

Abstract

A centering anchor arrangement for a conduit having an inner liner 68 extending with clearance through an outer pipe, a layer of flexible and compressible insulating material 82 overlying the inner liner 68 and the space between the insulating material 82 and the outer pipe being filled with a rigid refractory material 78, comprises a band 74 which encircles the inner liner 68 and a plurality of tubes 76 upstanding from the band 74 into the refractory material 78. The space within the tubes 76 is filled with a compressible insulating material 90, which material overflows into a void in the rigid refractory material 78. In an alternative embodiment (Fig. 1, not shown) the anchor member 14 is of generally truncated conical form, the smaller diameter end being connected to the liner member 2 and the larger diameter end to the pipe member 6, compressible insulating material 18 being provided between the radially outer conical surface of the anchor member and the rigid material. <IMAGE>

Description

SPECIFICATION Centering anchor arrangements for high temperature conduits The present invention relates in general to lined high temperature conduits and, in particular, to centering anchor arrangements and methods of fabricating the same for the inner liners of such conduits.

It is known to utilize lined conduits for conducting high temperature media such as hot combustion gases and the like. Such conduits include an inner liner which is directly contacted with the high temperature medium and which is surrounded by an outer pipe. The space defined between the inner lining and the outer pipe is filled with castable insulating and refractory material. A basic defect in these prior art conduits is that, due to the large difference in the coefficients of expansion between the liner and the castable material, the liner expands and often collapses and becomes distorted due to its contact with the castable material, which is a hard bricklike substance.

In our co-pending U.K. Patent Application No. 8211647 (Serial No. 2,118,672 A), we have described and claimed a conduit wherein a flexible insulating blanket is disposed around and in contact with the conduit liner member, whereby when in use the liner member may expand freely on being exposed to high temperatures. With such a conduit, it is most desirable that the liner member be mounted centrally within the outer pipe member, and be anchored against axial movement, and the principal object of the present invention is to provide an arrangement whereby this may be achieved whilst still permitting the expansion of the liner when subjected to thermal stress.

Accordingly, one aspect of this invention provides a centering anchor arrangement for an inner liner member of a conduit which includes a pipe member provided internally with a layer of castable rigid material through which the liner member extends, which centering anchor arrangement comprises at least one anchor member connected at one end to the inner liner member so as to extend outwardly into the castable rigid material, with clearance between the radially outer surface of the anchor member and the rigid material, and compressible insulating material disposed in said clearance.

Most preferably, the inner liner member extends with clearance through the layer of castable rigid material within the pipe member, there being a flexible insulating blanket disposed in the clearance between the liner member and the rigid material to permit the free thermal expansion of the liner member, when in use.

In one embodiment of this invention, the anchor member is tubular and extends generally radially with respect to the liner member into the rigid material, there being a void between the radially outer end of the anchor member and the rigid material and the compressible insulating material filling the void and the interior of the tubular anchor member. Advantageously, a plurality of radiallyextending tubular anchor members are provided, spaced circumferentially around the liner member.

Alternatively, the anchor member may be of generally truncated-conical form, the smaller diameter end of which is connected to the liner member, and the compressible insulating material being provided between the radiallyouter conical surface of the anchor member and the rigid material.

According to another aspect of this invention, there is provided a method of fabricating a centering anchor arrangement for centering and anchoring a liner member within a pipe member having castable material between the liner member and pipe member, comprising positioning and compressing flexible insulating refractory material within at least one hollow tube which extends outwardly from the liner member, covering such portion of the flexible insulating refractory material as extends beyond the tube member with a cap of heat vaporizable material, positioning the castable material between the liner member and the pipe member to surround the tube member and associated cap, and heating the cap to vaporize the material thereof, to permit close contact between the insulating flexible material within and extending beyond the tube member and the castable material.

By way of example only, certain specific embodiments of this invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is a sectional view of a high temperature lined conduit including a first embodiment of anchor arrangement in accordance with the invention; Figure 1 A is a front elevation of the anchor member used in Figure 1; Figure 2 is a sectional view of an elbow lined conduit with a second embodiment of anchor arrangement in accordance with the invention; Figure 3 is a sectional view taken along line 3-3 on Figure 2; Figure 4 is a sectional view taken along line 4-4 on Figure 2; Figure 5 is a plan view with portions removed for clarity taken along line 5-5 on Figure 2; Figure 6 is an enlarged sectional detail partial view of part of the anchor arrangement shown in Figure 4;; Figure 7 is a sectional view of a conduit tee portion and connected elbow portions in accordance with the invention; Figure 8 is a partial sectional view taken along line 8-8 of Figure 7; Figure 9 is a sectional view of a double tee or cross conduit structure including an anchor arrangement in accordance with the invention; and Figure 10 is a sectional view taken along line 10-10 on Figure 9.

Referring to Figure 1 of the drawings, there is shown a high temperature lined conduit generally designated 10 having a liner member or tube 2 wrapped with a flexible insulating and refractory blanket 4 which has been compressed to a fraction, preferably one half, of its original thickness. A pipe member 6 is disposed around the compressed blanket 4 and spaced therefrom. Castable refractory material 8 is provided in the space between the pipe member 6 and compressed blanket 4.

In a preferred embodiment of the invention, the liner member or tube 2 is made of temperature resistant stainless steel and pipe member 6 is made of carbon steel. Blanket 4 is made of woven or non-woven ceramic fiber, for example, aluminum oxide or silicon oxide fibers. A material actually used for this blanket is known by the trade name Insblanket which is distributed by the A.p. Green Company of Mexico, Missouri.

A plurality of wire anchors 12 are welded to the inside diameter of pipe member 6 adjacent its ends. At one end of pipe member 6 is a pipe flange end portion 30 which carries a flange having a plurality of flange holes 36 therethrough for connecting the conduit to other structures. Near one end of liner member 2 is welded a slotted or unslotted cone or anchor member 14 which is welded at its smaller diameter end to the outside diameter of liner member 2 and, at its larger diameter end to the inside diameter of pipe member 6.

Anchor member 14 includes inwardly extending fixing members 16 which are embedded in the castable material 8. One face of the anchor member 14 facing the major portion of the castable material 8 is covered with an insulating compressible material 18. This material may, for example, be of a similar or slightly denser substance as that making up the blanket 4 and cemented to the face of anchor member 14.

As best shown in Figure 1A, anchor member 14 may be provided with two sets of circumferentially spaced slots 15 in the opposite end portions of the anchor member. Each of the slots of one set extends inwardly from the inner edge of the anchor member adjacent liner 2 (see Figure 1) to a point short of the opposite end portion, while each slot 15 of the other set extends inwardly from the outer edge of the anchor member adjacent pipe member 5 (see Figure 1 ) to a point short of the opposite end portion.These sets of slots 15 providing the anchor member with the requisite flexibility to compensate for the high thermal gradient, as for example 1400 F (760 C), extending from one end portion of the anchor member to the other end portion and thereby reduce the thermal stress thereon and increase the fatigue life of the anchor member. In some applications where the thermal gradient across anchor member 14 is of a lesser value, the number of slots 15 may be reduced or the slots may be omitted from the outer edge-end portion of the anchor member or from both end portions depending upon the thermal gradient sought to be achieved across the anchor member.

By connecting the inner liner member to the outer pipe member in this fashion, liner member 2 is permitted to expand from this anchoring point without becoming misaligned with the pipe member 6.

A female slip joint end 22 is provided at one end of liner member 2 and a male slip joint end 20 is provided at an opposite end thereof. A female slip joint end 22 of one liner member 2 can thereby receive the male end 20' of a connected liner member 2' of an adjacent conduit length 10'. Spaces 24 and 26 are left without blanket material 4 to permit free expansion of the male and female ends of each liner member. Conduit 10' is similarly provided with spaces 24' and 26' at its male and female liner member ends 20' and 22', respectively.

To connect pipe member 6 of conduit 10 to pipe member 6' of conduit 10', a backing strip or ring 34 is first welded to the inside diameter of one end of pipe member 6'. The exposed face of castable material 8 facing conduit 10' is then covered by a double layer of refractory paper 32 which is of the same chemical composition as the refractory material 18 and the blanket 4. A suitable paper is known by the trade name Inspaper distributed by the A.P. Green Company, identified above.

After securing the refractory paper material 32 to the castable material 8, conduit 10' is brought into engagement with conduit 10 with portions of the backing ring 34 extending beyond the pipe member 6' moving into a suitably provided space 28 left in the castable material 8. The joint between pipe members 6 and 6' is then completed by a welded seam 38.

In this fashion, conduit lengths 10 or 10' of, for example, over ten feet (about 3m) can be connected together to produce a conduit of any desired length.

Conduits, such as the one described above, have already been successfully tested for periods in excess of 2800 hours at internal temperature of 1650'F (about 900"C) and provide an external temperature of 250 F (about 120 C). The conduits may be used for conveying any high temperature medium such as high temperature combustion gases, steam or air.

Each conduit 10 or 10' is manufactured by first wrapping and compressing the refractory blanket 4 around the liner member 2. The blanket material is preferably compressed to approximately one-half its original width and maintained in its compressed position by a layer of heat vaporizable material which is thereafter held by, for example, tape. In practice, a polyethylene sheet is utilized which is held by masking tape. At this point, two alternate procedures can be followed. In a first procedure, the liner 2 with wrapped compressed and secured blanket 4 is positioned within the pipe member 6 and anchor member 14 is welded into position. Stainless steel wire anchors 12 are then welded to the inside diameter of pipe member 6 or already in position before liner member 2 is inserted.

After centering liner 2 with blanket 4 within the pipe member 6, the castable material 8, in flowing form, is filled into the space between blanket 4 with vaporizable layer therearound and pipe member 6.

The entire conduit construction, for example the connected conduits 10 and 10', are then assembled and hot gases are supplied through the interior of the liner members. The vaporizable layer being exposed to this heat is transformed into a gas and escapes from between the blanket 4 and the castable material 8. The heat also sets the castable material 8 if it has not already been set. With the removal of the vaporizable layer, and due to the compressed state of blanket 4, blanket 4 is then brought into close association with the castable material 8 and the completed conduit assembly is ready for use. In practice, the tape holding the polyethylene layer has been found to deteriorate and not to adversely effect the use of the conduit assembly.

In a second possible manufacturing procedure all of the steps of the first procedure above are repeated except that the pipe member 6 is initially provided with the castable material 8 having a bore defined therethrough for receiving the liner member 2 with wrapped compressed blanket 4.

It has been found that by rigidly anchoring the liner 2 to the pipe member 6 at only one location, that is through anchor member 14, the liner member 2 can expand and contract freely as required. This freedom is permitted through the resiliency of insulating refractory blanket 4 as well as the flexible refractory material 18 on one face of the anchor member 14 and the refractory paper 32 between the castable material 8 of conduit 10 and castable material 8' of conduit 1 0'.

It is also advantageous to position the female and male slip joint ends in a particular fashion depending on the orientation of the conduits 10 and 10' and on the flow of hot medium through the interior of the conduits.

With a horizontal run as shown in Figure 1 and with a medium flow in a direction of arrow 40, the upstream liner member 2' should have a male end 20' and a downstream liner member 2 should have a female end 22. For vertical runs, these slip joints are oriented so that, in a flow direction, the upstream liner member has a female end and the connected downstream liner has a male end. This arrangement for vertical and horizontal runs minimizes contamination of the gas flow within the conduits by materials released from the high temperature refractory blanket wrapping on the outer diameter of the liner members. This relationship is also preferred for elbow and tee members constructed in accordance with the invention to be described in detail hereinafter.

Turning to Figure 2, a conduit system is shown having a conduit generally designated 50 connected to a 90' elbow generally designated 60.

Conduit 50 is constructed in a similar fashion to conduits 10 and 10' of Figure 1 and include adjacent one end thereof an anchor member 52 physically interconnecting the liner member with the outer pipe member, preferably at an angle of 30' to the interconnected walls. In the embodiment shown in Figure 2, the simple pipe flange portion 30 is replaced by a two-stage flange 54 which is welded to the pipe member 56. Such a flange permits the connection of conduit 50 to any desired structure or system which requires a larger flange connection. Wire anchors 12, of Figure 1, are replaced, in two-stage flange 54 by wire anchors 58, shown through portions of the castable material 62 which have been cut away for clarity.Wire anchors 58 are made of stainless steel as were wire anchors 12 and are here supported on posts 64 which are welded at one end to the inside diameter of two-stage flange 54 and, at the other end, to the apex of wire anchors 58. Wire anchors 12' similar to those used in Figure 1 are also utilized adjacent an opposite end of conduit 50 near the fixing member 52. While an elbow type member 66 is connected to pipe member 56 in a similar fashion as the connection between pipe members 6 and 6' of Figure 1, the elbow liner member 68 of elbow 60 is positioned within pipe elbow member 66 in a different way.

Elbow liner member 68 has two male ends 72 since, with a medium flow in the direction of arrows 70, the above-identified preferred arrangement dictates the use of two male slip joints.

For properly positioning and holding the liner member 68 for expansion within pipe member 66, a centering anchoring arrangement generally designated 80 is provided at an intermediate location between ends 72, or at the bisect of the angle of the elbow. This positioning is preferred whether the elbow is a 90 elbow as shown or any other elbow whether larger or smaller in angle.

The anchoring arrangement 80 comprises a ring-like reinforcing band 74 which is welded to the outer diameter of elbow liner member 68. Extending radially outwardly from reinforcement band 74 are a plurality of hollow tubes or pins 76. These tubes are preferably disposed in two rows which are spaced from each other in the axial direction of liner member 68, as shown in Figure 2. As shown in Figure 4, with portions of the castable material 78 removed for clarity, each row of tubes or pins 74 includes 3 tubes or pins which are offset from the tubes or pins of the other row by 60 .

In completing the elbow structure, elbow liner member 68 is surrounded with compressed flexible refractory blanket 82 which in turn is surrounded by castable material 78.

This structure can be manufactured with the method utilized to manufacture the straight conduit sections with the castable material 78 being held by wire anchors 12" adjacent the ends of the elbow 60. The shape and mounting of wire anchors 1 2" are best shown in Figures 3 and 5. In Figure 5, the wire anchor 12" is shown welded at its semicircular base 12a with its arms 12b at an angle to a forward edge 66a of elbow pipe member 66.

This mounting and positioning of anchors 12" are similar to the mounting and positioning of other anchors 12' and 12 utilized in conduits 50 and 10 respectively. As with Figure 4, Figure 3 shows portions of the castable material 78 cut away for clarity to reveal the anchors 12".

Figure 6 shows a single pin or tube 76 shown in greater detail. Hollow tubes 76 are filled with flexible compressible insulating and refractory material 90 which is similar in composition to the blanket material 82 but preferably is of a non-woven material such as, for example, the material known under the trade name of Inswool distributed by the A.P. Green Company identified above. As shown in Figure 6, the amount of refractory flexible material 90 overflows the cavity formed by a hollow tube 76 and extends into a void in the castable material 78. This permits the thermal expansion of the tube 76 serving as an anchor member, while, at the same time, maintaining and centering the position of the elbow liner member 68 with respect to the castable material 78 and the pipe member 66.

In manufacturing the elbow assembly, each tube 76 with overflowing flexible refractory material 90 is covered with a heat vaporizable layer or cap 88, preferably made of polyethyk ene in accordance with a preferred embodiment of the invention. The cap 88 is secured temporarily by electrical tape 92 or the like and, in a similar fashion to the layer 84 maintaining and compressing the blanket 82, is evaporated by hot gases or medium supplied through the interior of the liner member 68. The tape 92 has been found to deteriorate and not affect the operation of the conduits as with the tape holding the layer 84 around the compressible blanket 82.

Turning to Figure 7, a 454 tee structure is shown which is formed by the intersection of two straight conduit portions.

The illustrated 45" angle tee can be replaced by a tee of any angle smaller or larger than 45 without departing from the principles of the invention.

Elbows 110 and 120 are constructed in a similar fashion to elbow 60 shown in Figure 2 and are connected to the ends of tee 100 in a similar fashion to the connection between conduit 50 and elbow 60 of Figure 2 and between conduits 10 and 10' of Figure 1.

Tee 100 comprises a first liner member 102 which is connected to an intersecting second liner member 104. A suitably provided oval aperture 1 26 is provided in first liner member 102 to establish communication between liner members 104 and 102.

Welded or otherwise connected to a portion of the outer diameter of first liner member 102 is a reinforcing band 118 having a plurality of anchor members or tubes 122 extending therefrom and into a castable material 124 positioned between the first and second liner members 102 and 104 and first and second pipe members 106 and 108.

As shown in Figure 8, the reinforcement band 118 extends around approximately one half the outer diameter of first liner member 102 and has a plurality of pins or tubes 122 distributed along the band 118. As shown in Figure 7, the tubes 122 are preferably positioned in two rows which are offset with respect to each other in the axial direction of first liner member 102 and, as shown in Figure 8, the pins or tubes 122 of one row are offset with respect to those of the other row.

Also as shown in Figure 7, the overall centering and anchoring arrangement 128 comprising the band 118 and members 122, is positioned approximately at the intersection between the axes of the first and second liner members 102 and 104. As described above, both the first and second liner members are wrapped with compressed flexible refractory and insulating material or blankets 112 and 114 with an additional compressed blanket covering 116 covering the junction between first and second liner members 102 and 104.

The requirement for this separate additional blanket will be treated in greater detail hereinafter.

By positioning the anchoring and centering arrangement 128 near the junction between the first and second liner members, the liner member assembly 102, 104 is mobilized at this point and permitted to expand freely in all directions away from this point through the cushioning action of the blankets 11 2, 114 and 116. Suitably provided male and female slip joints are connected to the ends of first liner member 102 and the one free end of second liner member 104.

While the reinforcement band 118 is shown as semicircular, the band can be larger or smaller as required.

Anchors are also utilized and connected to the inner diameter of the first and second pipe members 106 and 108 for maintaining the position of castable material 124 as with the other embodiments described above. pins or tubes 122 are mounted and fabricated to the rest of the structure in the same way as pins 76 of the embodiment shown in Figures 2-6.

In the fabrication of the 45 tee structure shown in Figure 7, liner member 104 is welded to liner member 102 prior to the welding of first and second pipe members 106 and 108 together. The application of the additional compressed blanket covering 116 at and adjacent the weld joint is then accomplished prior to the welding of first and second pipe members 106 and 108 together.

Similarly, the double tee shown in Figure 9 is fabricated by welding tee liners 142 and 143 to liner 140 prior to welding pipe members 154 and 156 to pipe member 152 so that compressed flexible refractory and insulating material can be applied to cover the weld joint areas between liner members 140, 142 and 143.

Turning to Figures 9 and 10, a double tee or cross structure 130 is shown.

Cross or double tee 130 comprises a liner member 140 wrapped with compressible flexible refractory and insulating blanket 148 which is surrounded by castable material 134 and pipe member 152 in a fashion similar to the construction of the other embodiments of the invention. Castable material 134 extends into the double tee arms formed by tee pipe members 154 and 156 with tee liners 142 and 143 which themselves are wrapped with blanket portions 150 and 151.

As with the other embodiments of the invention, the castable material 134 is maintained in the position by a plurality of wire anchors 144 and 146 welded to the inner diameters of the respective pipe members and near the ends of the pipe members.

The double tee or cross structure includes an anchoring and centering arrangement 158 which, as with the embodiments shown in Figure 7 for the 45 elbow is positioned at the junction between the main conduit section and the tee sections or arms. The centering arrangement 158 comprises a reinforcing band 136 which is welded to the outside diameter of liner 140 and provided with the necessary holes to permit communication between the tee lines 142 and 143 of the mean liner 140. Extending from band 136 are a plurality of pins or hollow tubes 138 which are positioned in two offset rows and staggers as shown in Figures 9 and 10. Expansion is thus permitted from centering means 148 while the respective positions of the liners and the pipes are maintained.

If the end of the double tee 130 is to expand into a chamber that end of the refractory 134 is protected by a cone member 160 which is covered by flexible refractory material 162 such as Inspaper, heretofore identified.

The conical member 160 is to be welded at its outside diameter to the inside diameter of pipe member 152. The inside diameter of cone member 160 has clearance with the outside diameter liner member 140 to allow liner member 140 to expand radially without contacting the inside diameter of cone member 160. If one end of double tee 130 is to be fitted into the end of a standard pipe, this end of the double tee would then be constructed with a female slip joint welded to liner member 140 and no cone member 160 would be used. The refractory in this application would be flush with the flange face similar to the male end.

An example of a suitable castable usable in all embodiments of the invention is known by the trade name VSL-50 supplied by the A.P.

Green Company identified above.

Claims (14)

1. A centering anchor arrangement for an inner liner member of a conduit which includes a pipe member provided internally with a layer of castable rigid material through which the liner member extends, which centering anchor arrangement comprises at least one anchor member connected at one end to the inner liner member so as to extend outwardly into the castable rigid material with clearance between the radially outer surface of the anchor member and the rigid material, and compressible insulating material disposed in said clearance.

2. A centering anchor arrangement according to claim 1, wherein the inner liner member extends with clearance through the layer of castable rigid material within the pipe member, there being a flexible insulating blanket disposed in the clearance between the liner member and the rigid material.

3. A centering anchor arrangement according to claim 1 or claim 2, wherein the anchor member is tubular and extends generally radially with respect to the liner member into the rigid material, there being a void between the radially outer end of the anchor member and the rigid material and the compressible insulating material filling the void and the interior of the tubular anchor member.

4. A centering anchor arrangement according to claim 3, wherein a plurality of radiallyextending tubular anchor members are provided spaced circumferentially around the liner member.

5. A centering anchor arrangement accord ing to claim 4, wherein a reinforcing band is provided around the circumference of the liner member, the anchor members being mounted thereon in two axially-displaced rows.

6. A centering anchor arrangement according to claim 1 or claim 2, wherein the anchor member is of generally truncated-conical form, the smaller diameter end of which is connected to the liner member, the compressible insulating material being provided between the radiallyouter conical surface of the anchor member and the rigid material.

7. A centering anchor arrangement according to claim 6, wherein the larger diameter end of the anchor member is connected to the pipe member.

8. A centering anchor arrangement according to claim 6 or claim 7, wherein there is a plurality of circumferentially-spaced slots in the anchor member each of which extends from one end of the anchor member towards the other end thereof.

9. A centering anchor arrangement according to claim 8, wherein there is further plurality of circumferentially spaced slots in the anchor member each of which further slots extends from the other end of the anchor member towards the one end thereof.

10. A method of fabricating a centering anchor arrangement for centering and anchoring a liner member within a pipe member having castable material between the liner member and pipe member, comprising positioning and compressing flexible insulating refractory material within at least one hollow tube which extends outwardly from the liner member, covering such portion of the flexible insulating refractory material as extends beyond the tube member with a cap of heat vaporizable material, positioning the castable material between the liner member and the pipe member to surround the tube member and associated cap, and heating the cap to vaporize the material thereof, to permit close contact between the insulating flexible material within and extending beyond the tube member and the castable material.

11. A method according to claim 10, in which the liner member carrying the tube with associated refractory material and cap is inserted into the pipe member, whereafter the castable material is cast into the space between the inner surface of the pipe member and the outer surface of the liner member, thereby to surround the tube and associated cap.

12. A method according to claim 10 or claim 11, in which a reinforcing band is secured to the inner liner at the location where anchoring arrangement is to be provided, said band having the tube projecting generally radially outwardly therefrom.

13. A centering anchor arrangement substantially as hereinbefore described, with reference to and as illustrated in Figures 1 and IA or in Figures 2 to 10 of the accompanying drawings.

14. A method of fabricating a centering anchor arrangement substantially as hereinbefore described with reference to Figures 2 to 10 of the accompanying drawings.