GB1594946A

GB1594946A - Attaching a collar or flange to a prism or cylinder

Info

Publication number: GB1594946A
Application number: GB355577A
Authority: GB
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1978-01-26
Filing date: 1978-01-26
Publication date: 1981-08-05

Description

(54) ATTACHING A COLLAR OR FLANGE TO A PRISM OR CYLINDER (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method of attaching a collar or flange to, or around, the surface of a prism or cylinder. In the case of hollow prisms or cylinders, the surface may be an external surface, an internal surface, or both.

According to one aspect of the invention, there is provided a method of attaching a collar or flange to or around the surface of a prism or a cylinder comprising the steps of providing a first collar or flange in the form of two arcuate parts which fit together to form the first collar or flange, disposing the two arcuate parts of the first collar or flange in contact with the said surface so that the pairs of ends of the said arcuate parts substantially abut along a first line through the prism or cylinder, providing a second collar or flange in the form of two arcuate parts which fit together to form the second collar or flange, locating the two arcuate parts of the second collar or flange in contact with the surface so that the pairs of ends of the arcuate parts of the second collar or flange substantially abut along a second line through the prism or cylinder, the second collar or flange parts being adjacent to the first collar or flange parts and the said first and second lines not being parallel to each other, attaching the adjacent parts of the first and second collars or flanges to each other and then attaching the first collar or flange (or the parts thereof) to the surface of the prism or cylinder.

Thereafter, the said arcuate parts of the second collar or flange may be removed, leaving the first collar or flange attached to the surface of the prism or cylinder substantially accurately aligned for use - e.g. for attachment to another collar or flange or to a blank which is later to be disposed contiguous with the first collar or flange in or near the position at which the second collar or flange was located.

It will be appreciated that the second collar or flange serves as a jig for accurately locating and/or aligning the first collar or flange.

Preferably, the said first and second lines are at right angles or approximately so, and preferably, the arcuate parts of the first and second flanges or collars are formed by cutting (or other suitable forming operation) each of the flanges or collars diametrically into two substantially equal half parts.

Preferably, the pairs of ends of the arcuate parts of the first collar or flange are first attached to each other, e.g. by welding, and then the thus unified collar or flange is attached, e.g. by welding, to the surface of the prism or cylinder. Preferably the attaching is effected on that side of the collar or flange which will not be employed as the collar-or flange-face.

The collar or flange is preferably provided with an annular recess or chamfer on its flange or collar face at the radially innermost region thereof (at least) before it is cut or otherwise formed into the said arcuate parts thereof. When the unified collar or flange is attached to the surface of the prism or cylinder, a seal, e.g. a seal weld, may be emplaced in the annulus defined by the annular recess or chamfer and the surface of the prism or cylinder to prevent leakage between the flange or collar and the surface.

When the flange or collar is to be used as, e.g. a bearing, or seal of a bearing or as part thereof in rotating machinery applications of the prism or cylinder, it may not be necessary to provide the aforesaid seal.

The prism or cylinder may then be cut substantially in the radial plane of the face of the flange or collar, or slightly forward of the face, according to the proposed use of the prism or cylinder. Alternativelv, the prism or cylinder may be cut substantially in the radial plane of the forward face of the seal, preferably after the latter has been subjected to a finishing treatment giving it a substantially flat surface.

Another fitting, e.g. another flange, collar or blank may be attached to the face of the first flange or collar, with a gasket and/or drip ring therebetween if desirable or necessary, preferably after removing any undesirably protruding part of the prism, cylinder or first flange (e.g. weld material thereof).

The arcuate parts of the first flange or collar may each have a radial bore or drilling therethrough to permit pressure testing for leaks between the flange or collar and prism or cylinder when the assembly is being completed or is completed. After pressure testing, the bore or drilling may be closed off.

When the prism or cylinder is hollow, the procedure of the invention may be employed to attach a collar or flange to the interior and/or exterior surfaces of the prism or flange.

The method of the invention is particularly, but not exclusively, useful as a preparative step in the permanent or temporary closure of a pipeline carrying fluid at elevated temperatures and/or pressures, and/or when the fluid presents a hazard such as flammability and/or toxicity. The attach ment -of the collar or flange to the pipeline can be performed at any time before it is necessary or convenient to interrupt the flow of fluid through the pipeline.

In another aspect, the invention provides a prism or cylinder, e.g. a solid or hollow shaft, or a hollow prism or cylinder such as a pipeline having a flange or collar attached to an interior and/or exterior surface employing the method described above. The invention further provides an installation comprising a prism, cylinder or shaft having a flange or collar attached as described above.

The invention is now further described, by way of non-limitative examples thereof, and with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a front elevation of the face of a conventional hub-type flange being prepared for use in accordance with the invention, around a pipe-line shown in section; Figure 2 is an elevation of an auxiliary flange which is employed with the flange of Figure 1 in performing the invention Figure 3 is a side elevation of the flanges of Figures 1 and 2 emplaced around a pipeline which is in use; Figure 4 shows the hub flange attached to the pipeline, the auxiliary flange having been removed; Figure 5 shows the arrangement of Figure 4 with part of the pipeline removed; Figure 6 is a view like that of Figure 5 but with a short section of part of the pipeline protruding from the flange face; Figure 7 illustrates one manner in which the pipeline may be blanked off; Figure 8 illustrates one way in which a new length of pipe can be attached to the original pipeline; Figure 9 shows a step in the fitting of either the blank of Figure 7 or the- new pipeline of Figure 8; Figure 10 shows another application of the invention; and Figure 11 shows parts about to be assembled for blanking off a pipe end in accord- ance with another embodiment of the invention.

Reference is first made to Figure 1 wherein the flange 10 is seen to be cut in two arcuate halves 10a and 10b about a diametrical cut line A-A, the two halves being emplaced around the outer surface of a pipeline 11 which is in service. The radially innermost part 12 of the flange face is recessed about 1/4 to 3/8 inch before- the flange 10 is cut. The cut is recessed so- as to be divergent away from the flange face, as will be seen from Figure 3, where the visible recess is indicated by 13. In some instances, the cut may be recessed so as to be convergent away from respective faces of the flange 10. The included angle of the recessed cuts may be from 50 to 600, or thereabouts.

A bore 14 has been drilled radially from the outer to the inner peripheries of each half of flange 10 to permit pressure testing of the flange when it has been attached to the pipeline 11.

Figure 2 shows the face of an auxiliary flange 15 which has been cut along a diametrical line B-B into two arcuate halves 15a, 15b.

In Figure 3, the flange 10 and auxiliary flange 15 are shown emplaced around the pipeline 11 and bolted together with their cut lines A-A and B-B perpendicular to each other, the auxiliary flange 15 serving as a jig for the accurate alignment of the two halves of the flange 10. The accuracy of alignment may be improved and/or increased by the use of oversized bolts and/or dowels. While the flange 10 is thus maintained with its joint face flat, the flange halves 10a, 10b are joined together, by suitable welding and filling of the divergent recesses. Following the welding operation to join the two halves 10a, 10b, the flange 10 is then welded to the pipe by a conventional or suitable weld in the vicinity of the hub, as indicated by reference 17 in Figure 4. The weld 17 is preferably effected while the auxiliary flange 15 is attached to flange 10, but it may alternatively be made after the two halves of the auxiliary flange 15 have been removed. The annular recess 12 defined outwardly of the pipe 11 is then seal welded, and any weld metal protruding from the flange joint face removed by filling, milling or other suitable procedure.

At this stage, or subsequently, hydraulic or pneumatic pressure may be applied to the bores 14, and further welding and finishing performed if there should be any leakage between the inside of the flange and the exterior.

At some later time when it is convenient, desirable or necessary to interrupt the fluid flow through the pipe 11, the pipe 11 may be cut. As shown in Figure 5, the cut may be made flush with the flange face or possibly slightly recessed therein, so that the cut pipe has the general appearance of a conventional flanged pipe, and can be blanked off or coupled to the flange of another pipe (not shown) in the usual way, a suitable gasket being provided in the joint. Alternatively, as shown in Figure 6, the pipe 11 may be cut slightly proud (e.g. about 1/4") of the flange face, and a flange or blank 18 or other detail bolted to the flange 10 with a drip ring 19 between as shown in Figure 7, the axial length of the drip ring exceeding the axial length of the excess, proud remnant of pipe 11. The coupling of a flanged pipe 20 to the flange 10 employing a drip ring 19 is shown in Figure 8. As shown in Figure 9, the drip ring 19 is useful when the pipe 11 has been assymmetrically or badly cut forward of the flange face since it will accommodate the proud part of the cut pipe.

In Figure 10, the line 11 has become corroded, eroded or otherwise defective in section X-X, and the procedure of the invention is employed to remove the defective section XX after a suitable by-pass 24 has been installed. To this end, flanges 22 and 23 are attached to the line 11 in the manner described in relation to Figures 1 to 4, and the flanges may be pressure-tested for leakage. When the flanges 22 and 23 are satisfactorily attached, either the fluid flow is interrupted in the pipe 11 upstream and downstream of the part shown in Figure 10, or so-called stopples 25, 26 which are cup washers which are used for forming substantially fluid-tight seals in pipelines, passed into the pipe 11 immediately upstream and downstream of the rear faces of the flanges 22, 23 respectively from suitable valves, 27, 28 adapted for the purpose, the valves 29, 30 in the by-pass 24 being open before or after the stopples are in position. The stopples 25, 26 (temporarily) close the pipe 11 downstream thereof, and while the fluid flow is thus obstructed, the section XX of line 11 is cut, and the cut ends closed by blanks 31, 32 fastened to the flanges 22, 23, with drip rings between (not indicated) if necessary.

Since the cutting of the defective section XX, and the blanking off of the flanged ends only takes about 1/2 to 1-1/4 hours, e.g.

about 1 hour, the procedure of the invention reduces the time during which personnel are exposed to the potential risks involved when the fluid is retained by stopples, and the operations of inserting the stopples, cutting the defective pipe section and blanking off the remaining pipe, which may take 6 hours or more.

The stopples 25, 26 may be removed at an appropriate time in the known manner, and/or if a new pipe section is attached by flanges to the flanges 22, 23 of the original pipe 11.

In many instances, it may be preferable to employ as the flange 10 a blank having a diameter exceeding the diameter of the pipe 11 by several inches (e.g. a 10 inch blank for an 8 inch pipe), and which it bored to fit closely around the pipe. The resulting flange when thus formed can have its gasketcontacting or other sealing area radially outwardly of the seal weld(s), thereby reducing the risk of imperfect sealing. Similar ly, the flange 15 may be formed from an "oversized" blank or cap. An arrangement of this type is now described with reference to Figure 11 which shows an oversized blank flange 40 attached around a pipe 11. It will be seen that the flange 40 has been previously cut into two halves, and at the cut, each half has been formed to diverge outwardly from a radial plane at an angle of about 25 relative to the diametrical plane so that when the two halves are disposed together around the pipe 11, there is provided an outwardly divergent diametrical groove 41 on each face of the flange with an included angle of about 50". The two halves of the flange 40 are accurately disposed around the pipe 11 employing another flange (not shown) which is cut in halves and located around the pipe to serve as a jig for the halves of flange 40 as described with reference to previous embodiments.

While the jig flange is attached to the front face (the left hand face in Figure 11) of the flange 40, the latter is attached to the pipe 11 by welding the rear face thereto by welds 42 and the two halves of the flange 40 are joined by welding in the rear divergent groove 41, the welding material being indicated by reference 43. Thereafter, the jig flange is removed, and the front face of the flange 40 secured to the pipe 11 by a full continuous fillet weld 44, the attachment of the two halves of the flange being completed by the welding in the front divergent groove 41 using the welding material 45. The welding material 45 is then formed flat with the front face of the flange 40, and the attached flange tested for fluid-tightness by a hydraulic test made by subjecting water in radial testing bores 14, extending from the inner to the outer peripheries of each flange half, to a suitably high pressure, as described with reference to previous embodiments. Any leakage of water at the joints is evidence of an imperfectly - attached flange 40 and either further welding must, in such cases, be performed to remedy the defect or the flange must be rejected for use.

The area available for sealing the flange against another flange or like abutting member is provided by the substantially flat annulus indicated by the reference 46 between the notional co-axial cylinders defined by chain lines 47, 48. It is seen that the annulus 46 is radially outwardly of the weld 44.

At a suitable time, the pipe 11 is cut (a stopple, not shown, being disposed therein if necessary) and a short length 11a of pipe 11 may project forward of the front face of the flange 40, radially inwardly of the annulus 46.

A cap assembly 50 comprising an end cap 51 of internal diameter greater than the diameter of the pipe length 11a and of the weld 44, and preferably equal to or more preferably slightly greater than the inner diameter of the annulus 46 (i:e. equal to or more preferably slightly greater than the diameter of the notional chain line cylinder 48) welded by weld 52 to a flange 52 of diameter equal to that of flange 40 is attached to the flange 40 by bolts (not shown) extending through bolt-holes (not shown) in both flanges preferably with an annular gasket 53 therebetween. The annular gasket is sandwiched between the flanges 40 and 52 so as to seal against the annulus 46 of the flange 40 and an annulus (not indicated) of the cap assembly 50 thereby to form a fluid-tight joint at the end of the pipe 11.

WHAT WE CLAIM IS: 1. A method of attaching a collar or flange to or around the surface of a prism or a cylinder comprising the steps of providing a first collar or flange in the form of two arcuate parts which fit together to form the first collar or flange, disposing the two arcuate parts of the first collar or flange in contact with the said surface so that the pairs of ends of the said arcuate parts substantially abut along a first line through the prism or cylinder, providing- a second collar or flange in the form of two arcuate parts which fit together to form the second collar or flange, locating the two arcuate parts of the second collar or flange in contact with the surface so that the pairs of ends of the arcuate parts of the second collar or flange substantially abut along a second line through the prism or cylinder, the second collar or flange parts being adjacent to the first collar or flange parts and the said first and second lines not being parallel to each other, attaching the adjacent parts of the first and second collars or flanges to each other and then attaching the first collar or flange (or the parts thereof) to the surface of the prism or cylinder.

2. A method according to claim 1 in which the said arcuate parts of the second collar or flange are detached from the first collar or flange after the latter is attached to the surface of the prism or cylinder.

3. A method according to claim or claim 2 in which the first and second lines are at, or approximately at, right angles to each other.

4. A method according to any one of claims 1 to 3 in which the arcuate parts of the first and second collars or flanges are formed by cutting or otherwise suitably forming each of the collars or flanges substantially diametrically into two substantially equal half parts.

5. A method according to any one of claims 1 to 4 in which the pairs of ends of the arcuate parts of the first collar or flange are attached to each other and then the thus unified first collar or flange is attached to the surface of the prism or cylinder.

6. A method according to claim 5 - in which the unified collar or flange is attached to the surface of the prism or cylinder on the side opposite to the side to which the second collar or flange is attached.

7. A method according to claim 2 or any one of claims 3 to 6 as appendant to claim 2 in which after the detachment of the arcuate parts of the second collar or flange, sealing and/or attachment means are disposed between the first collar or flange and the surface of the prism or cylinder.

8. A method according to claim 7 in which the first collar or flange has an annular recess or chamfer and the sealing and/or attachment means is disposed in the space defined by the annular recess or chamfer and the surface of the prism or cylinder.

9. A method according to any one of claims 1 to 8 in which at least one arcuate part of the first collar or flange is provided with a bore extending from the radially outer periphery to the radially inner periphery thereof for receiving a pressurized fluid for testing for fluid-tightness between the collar or flange and the prism or cylinder.

10. A method of attaching a collar or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. continuous fillet weld 44, the attachment of the two halves of the flange being completed by the welding in the front divergent groove 41 using the welding material 45. The welding material 45 is then formed flat with the front face of the flange 40, and the attached flange tested for fluid-tightness by a hydraulic test made by subjecting water in radial testing bores 14, extending from the inner to the outer peripheries of each flange half, to a suitably high pressure, as described with reference to previous embodiments. Any leakage of water at the joints is evidence of an imperfectly - attached flange 40 and either further welding must, in such cases, be performed to remedy the defect or the flange must be rejected for use. The area available for sealing the flange against another flange or like abutting member is provided by the substantially flat annulus indicated by the reference 46 between the notional co-axial cylinders defined by chain lines 47, 48. It is seen that the annulus 46 is radially outwardly of the weld 44. At a suitable time, the pipe 11 is cut (a stopple, not shown, being disposed therein if necessary) and a short length 11a of pipe 11 may project forward of the front face of the flange 40, radially inwardly of the annulus 46. A cap assembly 50 comprising an end cap 51 of internal diameter greater than the diameter of the pipe length 11a and of the weld 44, and preferably equal to or more preferably slightly greater than the inner diameter of the annulus 46 (i:e. equal to or more preferably slightly greater than the diameter of the notional chain line cylinder 48) welded by weld 52 to a flange 52 of diameter equal to that of flange 40 is attached to the flange 40 by bolts (not shown) extending through bolt-holes (not shown) in both flanges preferably with an annular gasket 53 therebetween. The annular gasket is sandwiched between the flanges 40 and 52 so as to seal against the annulus 46 of the flange 40 and an annulus (not indicated) of the cap assembly 50 thereby to form a fluid-tight joint at the end of the pipe 11. WHAT WE CLAIM IS:

1. A method of attaching a collar or flange to or around the surface of a prism or a cylinder comprising the steps of providing a first collar or flange in the form of two arcuate parts which fit together to form the first collar or flange, disposing the two arcuate parts of the first collar or flange in contact with the said surface so that the pairs of ends of the said arcuate parts substantially abut along a first line through the prism or cylinder, providing- a second collar or flange in the form of two arcuate parts which fit together to form the second collar or flange, locating the two arcuate parts of the second collar or flange in contact with the surface so that the pairs of ends of the arcuate parts of the second collar or flange substantially abut along a second line through the prism or cylinder, the second collar or flange parts being adjacent to the first collar or flange parts and the said first and second lines not being parallel to each other, attaching the adjacent parts of the first and second collars or flanges to each other and then attaching the first collar or flange (or the parts thereof) to the surface of the prism or cylinder.

10. A method of attaching a collar or

flange to or around the surface of a prism or cylinder substantially as hereinbefore described.

11. A method according to claim 10 substantially as hereinbefore described with reference to the embodiments illustrated in the accompanying diagrammatic drawings.

12. A prism or cylinder having a flange or collar attached to or around a surface thereof in which the flange or collar has been attached by a method according to any one of claims 1 to 11.

13. A method of attaching a prism or cylinder to an object comprising attaching a collar or flange to or around the surface of the prism or cylinder employing the method of any one of claims 1 to 11, cutting through the prism or cylinder at or adjacent to one face of the collar or flange, and attaching the collar or flange to the object.

14. A method according to claim 13 in which the prism or cylinder is a hollow conduit for fluid and in which the said object is blanking-off means for closing the open end of the conduit after the latter has been cut through, or a second hollow conduit.

15. A method according to claim 14 performed when the first-named conduit contains a fluid having hazardous physical and/or chemical characteristics.

16. A method according to claim 14 or claim 15 comprising disposing in the firstnamed conduit means for temporarily obstructing the passage of fluid therethrough.

17. A method of blanking off a hollow conduit substantially as hereinbefore described.

18. A method of attaching to a hollow conduit a second conduit substantially as hereinbefore described.

19. A blanked-off hollow conduit when made by a method according to any one of claims 14 to 17.

20. Hollow conduits when joined by a method according to any one of claims 14 to 16 or 18.