Large diameter pipes are typically joined by flanges extending radially from the ends of pipes to be joined. The flanges are bolted together, and typically a gasket is inserted between the adjacent flanges before bolts are used to draw the two flanges towards one another and make up the join.

According to the present invention there is provided apparatus for spreading flanges of pipes, the apparatus comprising first and second pins capable of engaging bolt holes in adjacent flanges, and a force transmission system capable of exerting force on the pins when engaged in the bolt holes.

In preferred embodiments of the invention the force is exerted on a different axis from either of the pins, and typically displaced from the mating faces of the flanges, so that the apparatus can be employed without inserting any part of the spreading apparatus in between the flanges.

Typically the pins engage the bolt holes in respective flanges by friction, and can typically be provided with one or more formations such as ridges or other radial protrusions extending from the shank of the pin. Typically each pin has more than one formation on its shank, and in preferred embodiments, the formations on the shank are axially spaced along the shank. In especially preferred embodiments there are axially spaced groups of formations on each pin, one group of formations being positioned at one end of the pin adjacent to an end of the bolt hole into which the pin engages, and a second group of formations on the shank of the pin, typically located at or near a position on the shank of the pin that corresponds to an opposite end of the bolt hole into which the pin engages in use.

In preferred embodiments, the pin is simply slid axially into a bolt hole and can simply be pushed and pulled to the correct position. In preferred embodiments, the pin only grips the bolt hole when the axis of the pin is out of alignment with the axis of the bolt hole, and the formations, or groups of formations, at opposing ends of the shank of the pin engage the walls of the bolt hole on opposite sides, jamming the pin in the bolt hole and allowing

force to be exerted on the flanges by the force transmission system.

The force transmission system typically comprises a screw threaded device that can exert a spreading force between the pins, and thus between the flanges. Hydraulic devices can also be used instead of screw-threaded devices. The apparatus can typically comprise one or more brackets which engage the pins, and which also engage the screw threaded device. The bracket (s) are preferably attached to a pin/respective pins so that force is transmitted to the or each pin via the bracket. One bracket is typically provided for each pin, and at least one bracket typically has a threaded device to co- operate with the screw threaded device to transmit the spreading force to the pins. At least one of the brackets, and preferably both, extend in a radial direction with respect to the flanges, so that the screw threaded device can exert force between the brackets on an axis outwith the flange.

In preferred embodiments of the invention, the screw threaded device exerts force on the pins via the brackets so that the pins are forced out of alignment with the axes of the bolt holes, thereby engaging the pins within the bolt holes, and allowing the force to be transmitted to the flanges to push them apart.

One advantage of certain embodiments of the present invention is that because force can be exerted outwith the plane of the flange, the flanges can be

spread apart, and a full face gasket seal can be inserted between them before the flanges are secured together again by the bolts in a conventional manner.

In preferred embodiments of the invention the apparatus typically comprises one or more swivel devices, that are advantageously associated with the screw threaded device.

Optionally, the swivel device is located in a bore of the bracket, and the long axis of the swivel device is coaxial with the axis of the bore.

Optionally, at least one swivel device has a threaded bore through its long axis with which the screw-threaded device engages.

Preferably, the apparatus comprises one threaded swivel device and one unthreaded swivel device.

Preferably, the swivel device is provided with a further threaded bore in which a retaining pin engages in order to maintain the attitude of the swivel device with respect to the bracket.

Inclusion of the swivel device in the apparatus avoids or limits bending forces being applied by a screw threaded device between the brackets in the event of arcuate movement of the brackets when force is applied.

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig 1 is a schematic perspective view of apparatus for spreading pipe flanges; Fig 2 is a perspective view of a bracket assembly shown in the fig 1 apparatus; Fig 3 is an end view of a bracket of the fig 2 bracket assembly; Fig 4 is a side view of the fig 3 bracket; Fig 5 is a perspective view of the bracket; Fig 6 is a side view of a swivel device; Fig 7 is an end view of the fig 6 device; Fig 8 is a perspective view of the swivel device; Fig 9 is a side view of a further swivel device ; Fig 10 is an end view of the fig 9 device; Fig 11 is a perspective view of the second swiveldevice; Fig 12 is a side view of a screw threaded device used in the fig 1 apparatus; Fig 13 is a perspective view from one side of a bracket and pin assembly; Fig 14 is a perspective view from the other side of the fig 13 assembly; Fig 15 is a side sectional view of the fig 13 assembly; Fig 16 is a review of the fig 13 assembly ; Fig 17 is a perspective view of a further bracket ; Fig 18 is a side view of the fig 17 bracket;

Fig 19 is an end view of the fig 17 bracket; Fig 20 is a side view of a pin; Fig 21 is a side view of a second pin; Fig 22 is a side view of third pin; Fig 23 is a side view of a fourth pin; Fig 24 is a side view of a fifth pin; Fig 25 is a side view of a sixth pin; Fig 26 is a side view of a seventh pin; Fig 27 is a side view of a eighth pin; Fig 28 is a side view of a nineth pin; Fig 29 is a side view of a tenth pin; Fig 30 is a side view of a eleventh pin; Fig 31 is a side view of a pin assembly engaging within a bolt hole on a flange; Fig 32 shows a side sectional view of the Fig 24 pin; and Fig 33 shows a side sectional view of the fig 31 pin.

Referring now to the drawings, pipes 1,2 have flanges 3,4 with bolt holes 5, and are spread apart using one or more spreading devices 10, typically located at diagonally opposite sides of the abutting flanges 3,4. The spreading device 10 comprises brackets 12,13 respectively connected to outward faces of the flanges 3,4 by means of pins 15, various embodiments of which are shown in figs 20 to 26, which are driven apart by a threaded bolt 20.

The pins 15 are threaded at one end 15t which engages with co-operating threads on bores 16 through the brackets 12,13, leaving the opposite ends 15p of the pins 15 protruding from the brackets

12,13. The protruding ends 15p of the pins 15 all extend into the bolt holes 5 on the flanges and the tolerances on each pin 15 are typically chosen to be a close fit within the bolt holes 5, so that the pins 15 can be inserted into and removed from the bolt holes 5 if they are co-axial, and so that if there is a slight misalignment between the axes of the pin 15 and the bolt holes 5, the pins 15 tend to jam therein. The pin can still jam within the bolt hole 5 if the OD of the pin 15 is substantially less than the ID of the hole 5.

Each bracket 12,13 has a slot 17 extending end to end parallel to the bore 16, and a further bore 18 which extends laterally through a side face perpendicular to the slot 17, and the bore 16, and which intersects the slot 17, as is best shown in fig 5. A further slot 19 extends through the top of the bracket 12 to intersect with the slots 17 and the bore 18. The bore 18 receives a cylindrical swivel 22 as shown in figs 6,7 and 8. The swivel 22 has a threaded bore 23 through its long axis 22 and is located in the bracket so that the long axis 22a is coaxial within the axis of the bore 18, and the threaded bore 23 aligns with the slot 17.

In certain embodiments, identical swivel devices can be provided in each bracket 12,13 but can optionally have opposite threads. However, in certain embodiments, is unnecessary for a threaded bore 23 to be provided in each swivel device, or even for more than one swivel device to be provided at all. It is preferred to have one dummy

(unthreaded) swivel Figs 9,10 and 11 show a modified swivel device 25 for use in the bracket 13, and is typically used in conjunction with a swivel device similar to the swivel device 22 being provided in the other bracket 12. The modified swivel device 25 is again cylindrical, and has a blind ended unthreaded bore 26 extending across the long axis 25a of the swivel device 25. The swivel device 25 is located in the bracket 13 in the same manner as bracket 12 accommodates the swivel device 22, with the swivel device 25 being disposed in the bore 18, the axis 25a being coaxial with the axis of the bore 18, and the bore 26 being coaxial with the slot 17. A grub screw (not shown) is screwed into a further threaded bore 27 in the swivel 25 and typically the grub screw extends into the top slot 19 in order to maintain the attitude of the swivel 25 within certain parameters, namely so that the bore 26 does not rotate around the axis 25a so as to be inaccessible from the slot 17. The grub screw also retains the head of the bolt 20, and can have a ball spring plunger to releasably retain the bolt.

The threaded bore 23 of the swivel device 22 accepts a threaded bolt 20 as shown in fig 12. The bolt 20 is offered into the end-to-end slot 17 of the bracket 12 when the swivel 22 is located within the bore 18 as described above. The end of the bolt 20 engages within the bore 23 of the swivel 22, and the bolt 20 is turned to drive the bolt 20 through the swivel 22 relative to the bracket 12 until the bolt 20 is relatively far into the bracket 12. At that

point, a pin 15 is offered to the bore 16 of each bracket 12,13 and is screwed in tight. The protruding heads 15p of the pins are then inserted into an aligned pair of the bolt holes 5 on opposite flanges 3,4 so that the slots 17 on each bracket 12,13 are aligned. At that point, the bolt 20 is driven through the swivel 22 in the bracket 12 until the end of the bolt 20 engages either a substantially identical swivel in the bracket 13 with an opposite thread, or a modified swivel 25 as described above, or simply a part of the bracket 13.

Further driving of the bolt 20 through the swivel 22 after the bracket 13 has been engaged forces the two brackets 12, 13 apart.

The protruding heads 15p of the pins 15 are a close fit within the bolt holes 5 of the flanges 3,4, and can only move within the bolt holes 5 when they are precisely coaxial with the bolt holes 5. Any misalignment between the axes of the pins 15 and the bolt holes 5 when the pins are engaged therein results in jamming of the pin 15 within the bolt hole 5. The heads 15p of the pins 15 carry varying forms of annular ridges or protrusions 30,31. The protrusions 30,31 can be of various different designs, but are generally provided in axially spaced arrays along the axis of the pin 15, so that one or a group of protrusions 30 is provided near the end 15p, and another protrusion 31, or a group of protrusions 31, is provided at an axially spaced location on the pin nearer to the threaded end 15t.

The protrusions 30,31 can be provided singly or in

groups and can comprise smooth or corrugated surfaces. A particularly preferred embodiment is shown in fig 25 where 2 or more end protrusions 30 are provided at the protruding end 15p, and an array of 6 or more annular ridges is provided at 31.

Alternative embodiments of pins are shown in figs 20 to 24 and figs 26 to 30. The objective of the ridges and protrusions 30,31 is illustrated in fig 31, which shows a bracket 12 carrying a pin 15, the head 15p of which is engaged in a bolt hole in 5 in flange 3. The pin 15 has a Z axis which is being forced out of alignment with the Z axis of the flange 3 by the force F exerted on the bracket 12 by the bolt 20 (not shown in fig 27). The misalignment between the axes of the pin 15 and the bolt hole 5 causes the top surface of protrusion 30 to jam against the top surface of the bolt hole 5, and the bottom surface of the protrusion 31 to jam against the bottom surface of the bolt hole 5. The protrusions 30,31 bite into the inner surface of the bolt hole 5 and prevent axial movement of the pin 15 out of the bolt hole 5. Thus, the brackets are held in contact with the flanges at their outer faces and the radial displacement of the bolt from the bolt holes by means of the brackets means that force can be applied by the bolt 20 to separate the flanges without any part of the apparatus being disposed in between the flanges. This is advantageous, because full-face gaskets can be applied between the flanges when they are separated by one (or preferably multiple) spreading apparatus.

The swivels 22 are useful but not essential, as they help to relieve strain on the bolt 20 as it tends to move in an arc. However, satisfactory embodiments can be constructed without swivels.

Once the pins 15 jam within the bolt holes 5 of the respective flanges, increasing force exerted by the bolt 20 tends to drive the protrusions 30,31 into the inner surface of the bolt holes 5, making slipping of the pins within the bolt holes less likely. Several annular protrusions at each of the locations 30,31 are preferred because the load exerted on the bolt hole 5 by the protrusions can be distributed over several protrusions rather than on a single protrusion, so the likelihood of damage to the pins and the inner surface of. the bolt hole 5 is reduced. In fact, a satisfactory pin 15 can be a simple threaded shank. Furthermore, it should be noted that while protrusions and annular ridges and the like can enhance the gripping ability of the pins within the bolt hole, they are merely a preferred embodiment, and satisfactory embodiments of the invention can be constructed without annular protrusions.

Certain modified embodiments are shown in figs 14- 19. Figs 13-16 show a bracket assembly 40 having a pin 41, and an integral swivel 42 having a threaded bore 43 that aligns with a slot 45 through the bracket 40. The bracket 40 functions in a similar manner as the bracket 12 described above. The pin 41 is inserted into the bolt hole 5 so that the

swivel 42 and the bore 43 therethrough are spaced radially outward from the edge of the flange. A bolt 20 is passed through the slot 45 and bore 43 and is driven until the end of the bolt 20 engages the opposite bracket 13 (or another integral bracket similar to bracket 40).

A simplified bracket 50 is shown in fig 17, having a bore 56b for accepting a pin 15, and a transverse bore 58 for receiving a swivel 22 as previously described.

Table 1 attached shows test results for some of the pins shown in the figures, with variations shown with reference to the pins in Figs 32 and 33. It can be seen from the table that better grip can be achieved by lower ridges 30, longer spacing between the ridges 30,31, longer brackets, better steel, several protrusions rather than a single protrusion and radiused protrusions as shown in Fig 32.

In certain embodiments of the invention, it can be advantageous to make the brackets longer so that the force is applied by the bolt 20 on an axis that is radially spaced far from the axis of the bolt holes.

This is an advantage because it increases the leverage applied by the bracket to the pin when the bolt 20 is driven through the bracket 12 and this enhances the grip of the protrusions on the pin against the inner surface of the bolt hole, making slippage less likely. A further advantage of this is that the spreading apparatus is spaced radially

from the working surface between the flanges, and a gasket can thereby be inserted more easily.

A further advantage of certain embodiments is that is no longer necessary to insert any part of the spreading apparatus in between the flanges to be separated, because the pins can be inserted from the outward side of the bolt holes.

Modifications and improvements can be incorporated without departing from the scope of the invention.

TABLE 1<BR> # Force Generator: Enerpac RC102 Hydraulic Cylinder, 10,216KGF@ 10,000 PSI<BR> # Pressure Generator: Enerpac Hydraulic Hand Pump 10,000PSI or 20,000PSI<BR> # Pressure Gauge: De Wit 98.000590,5-18 10,000PSI Calibrated<BR> # Flange Specimen: 6" ANSI B 16 150lbs A105N, Bolt Hole #22.35mm (specification) # 22.2 (measured) Pin Date #1 #2 d CC Steel Hardness Presure Comments Type [mm] [mm] [mm] [mm] [PSI] E 15/3/01 17 22 16 30 EN19 48 HRC 2100 Block BHS body, F Vertical, Serrations damaged D 15/3/01 17 22 18.3 30 EN19 48 HRC 1750 Pin stuck but easy out by hand. Clear indentation from the 'V' on flange BH D 15/3/01 17 22 18.3 30 EN19 48 HRC 3000 Very small serration damae, zero bending. Hammer out gently. E 15/3/01 17 22 16 30 EN19 48 HRC 3000 Serrations damaged, far end especially, zero bending. Hammer out gently. B 15/3/01 17 22 19.4 30 EN19 48 HRC 3000 Release loose. Serration damage to nos. 1 and 2 of 4 from end, zero bending. - - - - - - - - - Same bolthole used for the above 5 tests. D2 12/4/01 19 22 16 35 8620 60 HRC 2750 FAB II CC35 BHS body, F//Pin Z-axis. Crack on V, foot of. D212/4/01 9 22 16 35 8620 60HRC 3500 Crack as previous, zero bending, zero serration damage. Audible 'clicks' at 2500 and 3000PSI. - - - - - - - - - New boltholes both D4 17/4/01 19 22 16 35 EN19 48 HRC 2500 FAB II CC35 BHS body, F//Pin Z-axis. Zero damage, gentle hammer out. D4 17/4/01 19 22 16 35 EN19 48 HRC 3500 (Same BH & pin) Holding steady, but V- edge has failed by yield. Zero bending. D4 17/4/01 19 22 16 35 EN19 48 HRC 3000 Zero damage. BH deformity prevents #22 pins entry. Difficult initial grip. - - - - - - - - - New boltholes for 1st and 3rd.