WO1998048210A1

WO1998048210A1 - A pipe fitting

Info

Publication number: WO1998048210A1
Application number: PCT/GB1998/001148
Authority: WO
Inventors: Andrew Welfare; Simon Graig Throup
Original assignee: Glynwed Pipe Systems Ltd.
Priority date: 1997-04-18
Filing date: 1998-04-20
Publication date: 1998-10-29
Also published as: AU7064898A; GB9707917D0; EP0975913A1

Abstract

A pipe fitting for installation in an aperture (21) defined by a wall comprises a generally tubular body (1) having a lower end portion (2) which is insertable through the aperture (21). An expandable annular sealing member (17) is disposed around the tubular body (1). In its unexpanded state the sealing member (17) is insertable through the aperture (21) but in its expanded state it has a maximum diameter greater than the diameter of the aperture (21). The sealing member (17) is designed so that it is substantially unstressed in the circumferential direction when expanded.

Description

A Pipe Fitting

The present invention relates to a pipe fitting for installation into a pre-drilled hole in a wall such as a wall of a fluid container. Particularly, but not exclusively, the invention relates to a pipe fitting intended for use with lined containers, for instance lined pipes. The invention also provides a method and apparatus for the installation of the pipe fitting.

A requirement often arises in pipeline networks to provide a service line connection to a main pipe, or to replace a faulty fitting already in place. In both cases the new fitting is inserted into a hole drilled in the pipe wall and some form of sealing means must be employed to ensure a tight seal between the pipe fitting and the pipe. For example, the hole in the pipe wall could simply be tapped and the fitting screwed into the pipe, or alternatively some form of sealing gasket could be located between the fitting and the rim of the hole.

Such an arrangement is described in British Patent number 956,591 which discloses a branch pipe fitting which is screwed into a tapped hole in a pipe wall. Sealing is provided by a resilient sealing gasket which fits around the branch pipe where it emerges from the main pipe, and bears against the external surface of the main pipe around the edge of the hole.

British Patent number 1574038 describes a tubular pipe fitting which is inserted into an unthreaded hole drilled in a pipe wall. An elastomeric deformable packing sleeve is positioned between the rim of the hole in the pipe wall and the tubular fitting. The end of the sleeve which extends from the external surface of the pipe wall has a radially extending annular flange. Means are provided to deform the sleeve in the region of the flange to provide a tight seal between the rim of the hole and the tubular fitting.

British Patent application number 2051991 A discloses an alternative arrangement for sealing a tubular pipe fitting within an unthreaded hole in a pipe wall. In this arrangement a flexible sleeve member is disposed between the rim of the hole and the pipe fitting, the sleeve being initially a loose fit within the hole. The pipe fitting has a flared end which is then drawn up into the sleeve causing it to expand and form a tight seal with the wall of the hole in the pipe.

Each of the above three described arrangements works satisfactorily when used in conjunction with pipes which do not have an interior lining. However, it has become common practice to provide conduits with linings, such linings generally being installed to remedy deficiencies in existing conduits, for example leaking joints, broken pipes, corrosion holes and the like. The linings may be thin, merely providing a leakage barrier, or relatively thick so as to provide some structural strength. In some cases, the lining is a pipe in its own right which is expanded against the walls of the original conduit. Some of the linings are fibre reinforced, i.e. hose types, whereas others are thermoplastic or thermoset resin based. Some of the linings adhere to the internal wall of the original conduit, whereas others have no adhesion at all. In addition, linings are sometimes installed in pipework to meet anti-corrosion requirements.

Linings can provide problems when a new fitting is to be inserted into a pipe and a hole must be drilled through the pipe and the lining. There may be no adhesion to the pipe wall, or adhesion of the lining to the pipe wall may not be uniform along the whole length of the pipe. In some places pockets or annular regions may have developed between the lining and the pipe wall. If the lining is separated from the pipe wall at the point of drilling the hole there is the problem of having to take up the lining when the fitting is inserted such that it is sealed against the pipe wall. Similarly, the actual process of drilling the hole in the pipe wall may well leave the lining with a torn edge which is detached from the wall of the pipe in the region of the hole. If the lining is not resealed against the pipe wall, fluid in the pipe can propagate along an annulus between the lining and the pipe wall, having potentially catastrophic consequences, particularly in the case of gas pipes. Any such annulus must be sealed to prevent a build up of fluid between the lining and the internal wall of the pipe. Effective sealing will also cure the problem of "wicking" whereby fluid is able to pass through fibres of the lining by virtue of the fact that the polymer resin may not be homogeneous throughout the woven fibres.

The above described arrangements are not suited for use in conjunction with such lined pipes as the sealing means are disposed either around the pipe fitting within the hole or substantially around the pipe fitting bearing against the external surface of the pipe. When installing fittings in lined pipes it is necessary to provide a seal that acts on the inside of the pipe wall and overlaps the cut edge of the pipe lining to prevent fluid getting between the lining and the inner pipe wall.

There have been various suggested pipe fittings and sealing means for use in conjunction with lined pipes. For example, European Patent Application No. 0339156 describes an arrangement in which a pipe fitting which is to be inserted into a hole in a pipe has a tapered end portion formed from a circular array of elongate projections. The ends of the projections are bent radially outwards and provide a seating for a elastomeric O-ring. A central member is pushed through the tubular fitting, subsequent to its insertion into the pipe hole, to radially expand the projections which in turn expand the O-ring to a diameter great enough to surround the edge of the hole in the pipe. The fitting is then partially drawn up through the hole so that the O-ring is compressed against the inner wall of the pipe and spreads out covering the edge of a cut pipe lining forming a seal. This arrangement has a disadvantage in that the projections do not apply pressure to the O-ring at all points around the hole in the pipe and therefore it is difficult to obtain a uniform and effective seal.

An alternative fitting is described in European patent specification number 0 645 575. This describes a fitting comprising a tubular stem and an outer deformable collar which is slidable on the stem. The collar has an annular flange which provides a seating for an elastomeric O-ring. Means are provided for driving the deformable collar onto a tapered end portion of the tubular stem to expand it whereafter partially drawing the fitting back up through the hole in the pipe presses the flange of the collar against the wall of the pipe around the hole so that it covers the edge of the cut pipe. The O-ring is compressed between the collars flange and the pipe providing a seal. In some embodiments an expandable washer is positioned between the collar and an annular flange at the end of the tapered portion of the tubular stem (the expandable washer being expanded by pushing it onto the tapered portion ahead of the collar) to provide an effective increase in the outside diameter of the tubular stem flange which presses the collar against the wall of the pipe. Although this fitting works well in many applications it has been found that it is not particularly well suited for use in smaller diameter pipes or in circumstances where the hole through the pipe/pipelining is relatively ragged (such as where the pipe lining is fabricated from a very fibrous material). In the latter case the relatively narrow O-ring may not be capable of providing an adequate seal, but may "bridge" across fibres leaving gaps therebetween.

Both the above described arrangements also suffer a disadvantage in that sealing is provided by an expanded and therefor stressed O-ring which can fail over time.

It is an object of the present invention to provide a pipe fitting which obviates or mitigates the above disadvantages. It is a further object of the present invention to provide a method and apparatus for installing the fitting in a pipe or other container.

According to a first aspect of the present invention there is provided a pipe fitting for installation in an aperture defined by a wall, the pipe fitting comprising a generally tubular body a lower end portion of which is insertable through the aperture, an expandable annular sealing member disposed around the tubular body, the sealing member in its unexpanded state being insertable through the aperture and in its expanded state having a maximum diameter greater than the diameter of the aperture, wherein in said expanded state the sealing member is substantially unstressed in the circumferential direction.

Preferably the sealing member is configured such that in said unexpanded state it is corrugated in the circumferential direction and in said expanded state the corrugations are substantially smoothed out.

The tubular body preferably has a flared lower end portion which is insertable into the pipe and the annular sealing member is expanded by forcing it onto said flared end portion.

The tubular body is preferably provided with a radially extending flange at its lower end and wherein in said expanded state the sealing member is pressed against said flange. The flange may preferably be annular and serve to compress the sealing member against said wall around the entire circumference of said aperture with the pipe fitting installed in the aperture. In preferred embodiments the pipe fitting includes means for expanding the sealing member.

For instance, such expanding means may comprise a sleeve disposed around said tubular body and axially movable relative thereto, whereby displacing the sleeve and tubular body axially relative to one another forces the sealing member onto said flared end portion of the tubular body thereby causing the sealing member to expand.

Locking means may be provided for locking the sleeve axially relative to the tubular body once the sealing member is expanded.

Such locking means may preferably comprise a spring member carried by one of the tubular body and sleeve which springs into engagement with the other of said tubular body and sleeve to lock the sleeve and tubular body together.

Preferably ratchet means are provided for securing the fitting in said aperture in said wall with the sealing member pressed tightly against the internal surface of the wall around the aperture.

The sealing member preferably comprises an elastomeric sealing material bonded to a washer. For instance, the elastomeric sealing material may be bonded to the washer when said washer is in an expanded state, the sealing member then being deformed into its unexpanded state, such that when the sealing member is subsequently expanded the elastomeric sealing material is substantially unstressed.

The present invention also provides a method of installing the pipe fitting in a pre-drill aperture in a container, comprising inserting said lower end portion of the tubular body into the container through said aperture, expanding the sealing member into its expanded state, and partially withdrawing the tubular body back through the aperture so that the expanded sealing member is pressed against the wall of the container.

The present invention further provides apparatus for installing the pipe fitting in an aperture in a container wall, comprising powered means for first withdrawing the tubular body through said sleeve to expand the sealing member and subsequently drawing said tubular body and sleeve up through said aperture to press said sealing member against the container wall. The apparatus preferably comprises a generally cylindrical housing defining an upper chamber housing a piston and a lower chamber which fits around an upper portion of the pipe fitting, a connecting member which connects the piston to the tubular body of the pipe fitting, means for driving the piston up said upper chamber to thereby draw the tubular body upwards, and restraining means for preventing the sleeve of the pipe fitting from moving with the tubular body until the washer has been expanded and thereafter allowing the sleeve to be drawn upwards with the tubular body.

The restraining means preferably comprise spring loaded members which in one position prevent the sleeve from moving, and wherein the spindle is adapted to cooperate with the spring loaded members to depress them once the spindle has moved to a position corresponding to full expansion of the sealing member, the spring loaded members when depressed allowing the sleeve to move with the tubular body.

The restraining means preferably further comprise a restraining member which is slidably received within the bore of the lower chamber and which bears against the sleeve of the pipe fitting and cooperates with the spring loaded members, the spring loaded members initially preventing the restraining member from moving but freeing the restraining member once depressed by the spindle.

According to another aspect of the present invention there is provided an expandable sealing member comprising an elastomeric sealing material bonded to a generally annular support, the sealing member being expandable from a first unexpanded configuration to a second expanded configuration, wherein the elastomer is bonded to the support with said support in said expanded configuration and the sealing member is subsequently deformed into said unexpanded configuration.

Preferably when in said unexpanded configuration the sealing member is corrugated in the circumferential direction.

Preferably the support is a washer (e.g. a metal washer).

According to a further aspect of the present invention there is provided an expandable seal, comprising an annular ring of sealing material which is in an unexpanded configuration is corrugated in the circumferential direction, said corrugations being substantially smoothed out to expand the seal. The seal could for instance be solid rubber or some other elastomer or sealing material.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a half sectioned illustration of a pipe fitting according to a first embodiment of the present invention;

Figs. 2a and 2b illustrate a first component of the pipe fitting of Fig. 1, Fig. 2a is a plan view from above and Fig. 2b is an axial section taken on the line b-b of Fig. 2a;

Figs. 3a and 3b illustrate a second component of the fitting of Fig. 1, Fig. 3a is a plan view and Fig. 3b is a section taken on the line b-b of Fig. 3a;

Figs. 4a to 4c illustrate a third component of the fitting of Fig. 1 , Fig. 4a is a plan view from above and Figs. 4b and 4c are sections of Fig. a taken on the lines b-b and c-c of Fig.4a respectively;

Figs. 5a to 5c illustrate a fourth component of the fitting of Fig. 1, Fig. 5a is a plan view from above and Figs 5b and 5c are sections taken on the lines b-b and c-c of Fig. 5a respectively;

Figs. 6a and 6b illustrate a fifth component of the pipe fitting of Fig. 1, Fig 6a is a plan view and Fig. 6b is a section taken on the line b-b of Fig. 6a;

Figs. 7a to 7c illustrate a sixth component of the pipe fitting of Fig. 1 , Figs 7a and 7c are plan views of opposite sides and Fig. 7c is a side view;

Figs. 8a and 8b are further illustrations of the component of Figs. 7a to 7c illustrating an intermediate step in its manufacture, Fig. 8a is a plan view from above and Fig. 8b is a cross-section taken on the line b-b of Fig. 8a;

Figs. 9a and 9b illustrate the fitting of Fig. 1 together with installation tooling, Fig. 9b being a cross-section taken on the line b-b of Fig. 9a;

Figs. 10a to 10c illustrate three stages of the process of installation of the fitting of Fig. 1 into a hole in a pipe;

Fig. 11 illustrates the fitting of Fig. 1 fully fitted to a pipe provided with an internal pipeliner and with the installation tooling removed; Fig. 12 illustrates a detail of the pipe fitting of Fig. 1; and

Figs. 13a to 13d illustrated an alternative installation tooling and installation method for installing the fitting of Fig. 1 in hole in a pipe.

Referring to the drawings, Fig. 1 illustrates a pipe fitting according to the present invention prior to fitting to a pipe, i.e. in a pre-installation configuration. Details of individual components of the fitting illustrated in Fig. 1 are illustrated in Figs. 2 to 8 whereas Fig. 1 illustrates the assembled fitting. The illustrations of Figures 2 to 8 are not, however, necessarily in scale with Fig. 1.

The fitting comprises an open ended tubular stem 1 (shown in detail in Fig. 2) one end of which is outwardly tapered defining a flared bottom end portion 2. The stem 1 may typically be manufactured from brass. The rim of the flared end portion 2 is curved out of plane (to approximately conform to the hoop curvature of a pipe to which the fitting is to be installed) and defines a radially outwardly extending annular flange 3 at its edge. An outlet aperture 4 is provided through the wall of the stem 1 near to its upper end. A solid cylindrical plug 5 is screwed into the top of the stem 1 to seal its open upper end. The plug 5 can be screwed up and down a short length of the top portion of the stem 1 between a lower position (illustrated in Fig. 1) in which it seals the outlet aperture 4 and an upper position in which the aperture 4 is opened (whilst the top of the stem 1 remains closed).

Between the outlet aperture 4 and flared bottom portion 3, the stem 1 is provided with an annular groove 6 in its outer wall (approximately mid-way along its length). The groove 6 provides a seating for a split spring "snap ring" 7 (shown in detail in Fig. 3) which may be fabricated from acetal. A narrow axially extending tab la projects from the outer wall of the stem 1, just below the groove 6. The spring tension in the snap ring 7 tends to open the snap ring 7 to increase its external diameter.

In the pre-installation configuration of Fig. 1, the snap ring 7 is prevented from expanding outwards by a cylindrical bush 8 (shown in detail in Fig. 4) which is disposed co-axially around the outside of the stem 1. The bush 8, which also may be fabricated from brass, is a close fit with the stem 1 but is slidable relative thereto. The internal surface of the bush 8 is provided with an annular groove 9 adjacent its upper end and with an axial groove 10 (shown in Figs. 4a and 4c) which extends from the annular groove 9 to a point just short of the bottom edge of the bush 8. The tab la of the stem 1 engages in the groove 10 to maintaining allignment between the stem 1 and the bush 8. A series of annular ratchet teeth 11 are provided around an upper portion of the outer surface of the bush 8, which is also provided with an axial groove 12 which extends along its length from top to bottom. The bottom end of the bush 8 is curved out of plane to match the curvature of the flange 3 of the stem 1.

An annular support member 13 (shown in detail in Fig. 5) is slidably fitted around the bush 8. The support member 13 has an annular recess 14 in its upper face which is interrupted by a narrow radially inwardly projecting tab 15 which is slidably received within slot 12 provided in the outer surface of the bush 8 and thus maintains alignment. The annular recess 14 provides a seating for a split ratchet ring 16 (shown in detail in Fig. 6) which has internal annular ratchet teeth which engage the ratchet teeth 11 of the bush 8. Ends of the split ratchet ring 16 terminate on either side of the tab 15 of the support member 13.

An expandable annular seal 17 (shown in detail Figs. 7 and 8) is disposed co- axially around a tubular portion of the stem 1 between its flared end portion 2 and the lower end of the bush 8. With the fitting in its pre-installation configuration shown in Fig. 1, the expandable seal 17 is circumferentially corrugated so that its internal diameter corresponds with the diameter of the stem 1 and its external diameter corresponds approximately with the outer diameter of the bush 8.

The seal 17 comprises rubber bonded to a metal washer 18 to provide a first annular sealing surface 19 covering the upper surface of the washer 18 and a lower annular sealing surface 20 partially covering the lower surface of washer 18. The sealing surface 19 defines circumferentially extending ridges 19a.

Referring to Figs. 8a and 8b, the seal 17 is fabricated by bonding rubber to the washer 18 when it is in its flat state (for instance the rubber may be applied in a mould, the washer resting on the outer periphery of its under surface so as to hold the other washer surfaces clear of the mould wall). The seal 17 is subsequently deformed (circumferentially corrugated) to the configuration illustrated in Figs. 7a to 7c, and Fig. 1, to reduce its outside diameter.

Installation of the pipe fitting in a pre-drilled hole 21 in a pipe wall 22 will now be described, with particular reference to Figs. 9 and 10 (in which the length of the pipe runs in the direction of arrow A). Figs. 9a and 9b illustrate the pipe fitting (prior to insertion in the hole 21) together with tooling used in the installation process. Referring to these figures, the installation tooling comprises a spindle 23 which is screwed into the open upper end of the stem 1. A generally cylindrical cup-shaped member 24 is slidably fitted around the spindle 23 with its lower rim resting on an annular shoulder 25 of the bush 8. The outer surface of the spindle 23 is screw threaded and is fitted with a washer 25 and nut 26 which retains the cup-shaped member 24 in position.

A relatively short cylindrical member 27 is disposed around the lower end of member 24 so that members 23 and 24 are axially slidable relative to one another. The lower end of cylindrical member 27 rests on the support member 13 of the pipe fitting and member 27 is held in place by a nut 28 which bears against its upper end and which is in screw threaded engagement with the member 24 below a circlip 29.

The tooling described above is adapted for manual installation of the fitting to an out of service pipe within which a hole 21 has been pre-drilled using any conventional drilling apparatus (which will not be described here). The installation is performed as described below in relation to Figs. 10a to 10c.

Referring firstly to Fig. 10a, the fitting is inserted through the aperture 21 until the support member 13 bears against the outer surface of the pipe wall 22. The underside of the support member 13 is shaped to "saddle" across the pipe in a particular orientation corresponding to the correct orientation of the stem 1 and bush 8 to match the curvature of the pipe. The size of the pipe fitting is matched to the size of the hole 21 so that the bush 8 is a relatively close fit within the hole 21.

For the next stage of the installation procedure the fitting is held against the pipe and nut 26 is turned whilst the spindle 23 is held to prevent rotation of the whole fitting. As nut 26 is turned, the spindle 23 is held (by insertion of an appropriate tool into its upper end) to prevent it rotating and it is thus drawn up through the nut 26 and through the cup member 24. However, since the bush 8 is held in position by the bottom edge of the cup-shape member 24 the bush 8 effectively drives the seal 17 onto the flared end portion 2 of the stem 1 as the stem 1 rises through the bush 8. The seal 17 radially expands as it is forced onto the end of the flared portion 2 until it assumes a "flattened" configuration trapped between the bottom edge of bush 8 and the flange 3 (the seal will not be "flat" but rather will conform to the curvature of the flange 3 and bush 8, the corrugations will, however, be "smoothed" out).

At this point, (illustrated in Fig. 1 Ob) the length of axial travel of the stem 1 through the bush 8 is such that the annular groove 6 in the stem comes into register with the annular groove 9 in the bush and the snap ring 7 springs outwards to lock the stem 1 and bush 8 against further relative axial movement. The relative axial movement between the bush 8 and stem 1 required to fully expand the seal 17 is known and is independent of the thickness of the pipe wall 22, the positions of the grooves 6 and 9 being determined accordingly. Thus, action of the snap ring 7 indicates that the seal 17 is fully expanded, and also prevents any further relative movement between the stem 1 and bush 8 which would tend to release the seal 17.

In the resulting configuration (illustrated in Fig. 10b) it will be seen that the rubber sealing strip 20 on the underside of the washer 18 seats around, and forms a seal with, the annular flange 3 of stem 1 , whereas the non-ridged portion of rubber sealing surface 19 seats around, and seals against, the lower edge of the bush 8. With the seal 17 in its expanded state the ridged portion 19a of sealing surface 19 extends beyond the bush 8 and thus to a greater diameter than the diameter of the hole 21 in pipe wall 22.

For the final stage of the installation procedure nut 28 is rotated whilst holding spindle 23 against rotation. Rotation of nut 28 thus draws member 24 up through the outer cylindrical member 27. Since the cup-shape member 24 is axially locked in position relative to the spindle 23 and pipe fitting, by virtue of nut 26, the stem 1 and bush 8 are drawn up through the hole 21 and up through the ratchet ring 16 which is held against axial movement by the shoulder 27a of outer cylindrical member 27. This is continued until the seal 17 is tightly compressed against the internal wall of the pipe 22. The ratchet action allows the seal to be "tightened" (whilst accommodating a range of pipe wall thickness) but prevents the stem 1 slipping back through the bush 8. The ratchet is illustrated in detail in Fig. 12 which shows that the teeth on the ratchet ring 16 are spaced by a distance equal to one and one half their pitch to allow movement in half pitch increments.

The curvature of the flange 3, and the lower end of the bush 8, conforms generally with that of the internal wall of the pipe 21 (fittings intended for pipes of different sizes will be provided with appropriate profiles) so that the expanded state of seal 17 also generally conforms with the curvature of the pipe wall and thus a good seal is formed around the whole periphery of the hole 21.

The installation tooling can then be removed. The pipe wall 22 is effectively clamped between the support member 13 and seal 17, the ratchet preventing any axial loosening of the fitting which might otherwise compromise the integrity of the seal.

A fully installed fitting, with installation tooling removed, is illustrated in Fig. 11 which is a view looking along the length of the pipe 22, i.e. in the direction of arrow A of Figs. 10a to 10c. In Figure 11 the fitting is shown installed in a pipe 22 fitted with an internal pipeliner (which may be of any conventional type) 22a, which is not shown in Figures 10a to 1 Oc.

The installation procedure of the fitting according to the present invention is relatively straight forward and incorporation of the snap ring 7 and ratchet provide for positive location of the fitting, and for maintaining the fitting in position, without the need for lock nuts etc. which might complicate the fitting and the installation procedure. The fitting is thus relatively cheap and is simple to assemble and install.

The portion 19a of the seal 17 provides a relatively large surface area making sealing contact around the hole 21 in the pipe 22. This large sealing surface provides for a good seal and also can accommodate any "raggedness" in the edges of the hole and in particular in the edges of any pipeliner that may be present. The fitting is thus particularly useful for use in relation to lined pipelines and similar containers. In addition, it has been found in practise that it is not necessary to have separate specifically dimensioned fittings for all diameters of pipe (in order to ensure that the profile of the expanded seal 17 matches the curvature of the pipe) but rather a single sized and shaped fitting can accommodate a range of pipe sizes. It is not absolutely necessary for the curvature of the flange 3 of stem 1 to exactly match the curvature of the pipe since the rubber sealing strip 19 and further deformation of the seal 17 as it is tightened against the pipe wall, can accommodate small differences whilst ensuring a good seal.

A further important advantage of the pipe fitting is that when the seal 17 is expanded it returns to a size/configuration similar to that in which it was manufactured (see Fig. 8) so that in the expanded configuration the rubber sealing surfaces are returned to substantially their original configuration and are not therefore subject to significant stress which might cause deterioration over time.

The tooling described above is suitable for manual installation of the fitting into an out of service pipeline. Suitable tooling could be provided for installation of the fitting to an in-service pipeline. For instance, conventional installation apparatus comprising a sealed bell housing (for instance the installation apparatus illustrated in European application number 0645575) could be readily adapted for installation of the fitting according to the present invention.

An alternative installation method using hydraulic installation tooling is illustrated in Figs. 13a to 13d. Although the installation tooling illustrated in Figs. 13a to 13d is different from that described above, the fitting is identical. The hydraulic tooling comprises an hydraulic cylinder 30 which fits around the upper portion of the pipe fitting so that its lower edge sits on the support member 13 with an annular abutment shoulder 30a bearing against the ratchet ring 16. Internally, the hydraulic cylinder 30 is divided into two compartments by a partition wall 31, that is an upper pressurised chamber 32 and a lower non-pressurised chamber 33. A piston 34 is slidably housed within pressurised chamber 32 and is integral with a spindle 35 which extends into none pressurised chamber 33 and is received in the top of the pipe fitting stem 1. An arrangement of spring fingers 36 are circumferentially spaced around the hydraulic chamber 30 so as to protrude through its wall into the none pressurised chamber 33. The internal ends of the spring fingers 36 are tapered for co-operation with a tapered portion 37 provided at the end of spindle 35 adjacent the top of the pipe fitting stem 1. An inner cylindrical sleeve 38 is disposed around the spindle 35, being a close fit within the bore of the chamber 33, between the spring fingers 36 and the bush 8 of the pipe fitting. That is, the lower end of sleeve 38 bears against the bush 8 and the upper end of sleeve 38 (in a pre-installation configuration illustrated in 13a and 13b) bears against the underside of spring fingers 36. The rim of sleeve 38 is bevelled for co-operation with the tapered spring 36 in a manner described below.

A first stage of the installation process is illustrated in Fig. 13b. Here, the fitting is simply inserted into a hole in the pipe wall 22, no hydraulic pressure being required for this. Once in the position illustrated in Fig. 13b, hydraulic fluid is introduced into chamber 32 below the piston 34 so that the piston 34 is pushed upwards. This draws the spindle 35 up through chamber 33 which in turn draws the stem 1 of the pipe fitting up through the aperture in the pipe and also, initially, through bush 8 which is held in position by sleeve 38 the top end of which bears against spring fingers 36. The stem 1 of the pipe fitting is drawn through the bush 8 until the sealing washer 7 is fully expanded on the flared end portion 2 of the stem 1 and snap ring 7 snaps into the groove 9 in the bush 8. This position is illustrated in Fig. 13c.

It will be seen that as the tapered end 37 of spindle 35 moves up through chamber 33 it rides over the tapered end of spring fingers 36 and forces them radially outwards to the position illustrated in Fig. 13c. In this position the spring fingers 36 are pushed back sufficiently far that their tapered ends are pushed back beyond the bevelled edge of the sleeve 38 so that as the piston 34 continues to rise the sleeve 38 is also drawn up with spindle 35 (the bevelled edge riding over the spring fingers 36 forcing the spring fingers 36 out yet further) so that now the whole pipe fitting is drawn up through the hole in the pipe to the position illustrated in Fig. 13d. This is continued until the seal 17 has been pressed sufficiently tightly against the internal wall of the pipe 22 to form a good seal. Thereafter the installation apparatus can be removed leaving the fitting as illustrated in Fig. 12 above.

It will be appreciated that this installation procedure is very straight forward and although illustrated by three separate Figures 13b to 13d it is essentially a single process of simply pumping the piston 34 up the hydraulic cylinder 30. As a modification the apparatus could be pneumatically powered, or even electrically powered (e.g. the spindle 35 could be solenoid driven).

It will be understood that many modifications could be made to the detailed fitting described above. For instance, the arrangement of the snap ring 7 and of the ratchet ring 16 could be replaced by screw threads and lock nuts. In addition, details of the expandable seal 17 could be varied. For instance, rather than fabricating the washer from rubber bonded to metal the washer could be, for instance, solid rubber or another suitable sealing material. Furthermore, rather than circumferentially corrugating the washer to provide for its expansion, the washer could be a simple split washer with ends that initially overlap.

As a further modification the flared portion could be omitted and the corrugated seal 17 expanded simply by compressing it between the bush 8 and flange 3 (which could be enlarged appropriately).

It will be appreciated that the fitting according to the present invention could be readily adapted for installation in a variety of different pipes and indeed other fluid containers. Modifications that may be made to the fitting to suit different applications will be readily apparent to the appropriately skilled person. For instance, there will be no need to curve the bottom of the stem 1 and bush 8 if the container has a flat wall.

Claims

1. A pipe fitting for installation in an aperture defined by a wall, the pipe fitting comprising a generally tubular body a lower end portion of which is insertable through the aperture, an expandable annular sealing member disposed around the tubular body, the sealing member in its unexpanded state being insertable through the aperture and in its expanded state having a maximum diameter greater than the diameter of the aperture, wherein in said expanded state the sealing member is substantially unstressed in the circumferential direction.

2. A pipe fitting according to claim 1, wherein in said unexpanded state the annular sealing member is corrugated in the circumferential direction and in said expanded state the corrugations are substantially smoothed out.

3. Apparatus according to claim 1 or claim 2, wherein the tubular body has a flared lower end portion which is insertable into the pipe and the annular sealing member is expanded by forcing it onto said flared end portion.

4. A pipe fitting according to any preceding claim, wherein the tubular body is provided with a radially extending flange at its lower end and wherein in said expanded state the sealing member is pressed against said flange.

5. A pipe fitting according to claim 4, wherein said radially extending flange is annular and serves to compress the sealing member against said wall around the entire circumference of said aperture with the pipe fitting installed in the aperture.

6. A pipe fitting according to any preceding claim, further including means for expanding the sealing member.

7. Apparatus according to claim 6 when dependant from claim 3 and any claim defiant therefrom, wherein said expanding means comprises a sleeve disposed around said tubular body and axially movable relative thereto, whereby displacing the sleeve and tubular body axially relative to one another forces the sealing member onto said flared end portion of the tubular body thereby causing the sealing member to expand.

8. A pipe fitting according to claim 7, wherein locking means are provided for locking the sleeve axially relative to the tubular body once the sealing member is expanded.

9. A pipe fitting according to claim 8, wherein said locking means comprises a spring member carried by one of the tubular body and sleeve which springs into engagement with the other of said tubular body and sleeve to lock the sleeve and tubular body together.

10. A pipe fitting according to claim 9, wherein the external surface of the tubular body is provided with a first recess and the internal surface of the sleeve is provided with a second recess positioned so the first and second recesses come into register when the sleeve is moved to a position corresponding to the fully expanded state of the sealing member, and wherein said spring member is carried within one of said recesses and springs to extend into both of said recesses when said recesses come into register.

11. A pipe fitting according to claim 10, wherein said first and second recesses are annular grooves and said spring member is a split spring ring.

12. A pipe fitting according to anyone of claims 6 to 11, wherein ratchet means are provided for securing the fitting in said aperture in said wall with the sealing member pressed tightly against the internal surface of the wall around the aperture.

13. A pipe fitting according to claim 12, wherein said ratchet means comprise ratchet teeth defined by said sleeve and a ratchet member disposed around and in engagement with said sleeve on the opposite side of said wall to said sealing member.

14. A pipe fitting according to claim 13, further comprising an annular support member for supporting the fitting within said aperture, which support member bears against an outer surface of the wall on the opposite side of said aperture to said sealing member with said fitting in situ.

15. A pipe fitting according to claim 14, wherein said annular support member provides a seating for said ratchet member.

16. A pipe fitting according to any one of claims 13 to 15, wherein said ratchet member is an annular ratchet ring disposed around said sleeve.

17. A pipe fitting according to any preceding claim, wherein said sealing member comprises an elastomeric sealing material bonded to a washer.

18. A pipe fitting according to claim 17. wherein said elastomeric sealing material is bonded to the washer when said washer is in an expanded state, the sealing member then being deformed into its unexpanded state, such that when the sealing member is subsequently expanded the elastomeric sealing material is substantially unstressed.

19. A pipe fitting according to claim 17 or claim 18, wherein the elastomeric material is bonded to both surfaces of the washer.

20. A pipe fitting according to any one of claims 17 to 19, wherein said washer is metal.

21. A method of installing a pipe fitting according to any preceding claim in a pre- drill aperture in a container, comprising inserting said lower end portion of the tubular body into the container through said aperture, expanding the sealing member into its expanded state, and partially withdrawing the tubular body back through the aperture so that the expanded sealing member is pressed against the wall of the container.

22. Apparatus for installing a pipe fitting according to claim 7 and any claim dependant thereon in an aperture in a container wall, comprising powered means for first withdrawing the tubular body through said sleeve to expand the sealing member and subsequently drawing said tubular body and sleeve up through said aperture to press said sealing member against the container wall.

23. Apparatus according to claim 22, wherein said means is hydraulically, pneumatically or electrically powered.

24. Apparatus according to claim 23, comprising a generally cylindrical housing defining an upper chamber housing a piston and a lower chamber which fits around an upper portion of the pipe fitting, a connecting member which connects the piston to the tubular body of the pipe fitting, means for driving the piston up said upper chamber to thereby draw the tubular body upwards, and restraining means for preventing the sleeve of the pipe fitting from moving with the tubular body until the washer has been expanded and thereafter allowing the sleeve to be drawn upwards with the tubular body.

25. Apparatus according to claim 24, wherein said restraining means comprises spring loaded members which in one position prevent the sleeve from moving, and wherein the spindle is adapted to cooperate with the spring loaded members to depress them once the spindle has moved to a position corresponding to full expansion of the sealing member, the spring loaded members when depressed allowing the sleeve to move with the tubular body.

26. Apparatus according to claim 25, wherein said restraining means further comprises a restraining member which is slidably received within the bore of the lower chamber and which bears against the sleeve of the pipe fitting and cooperates with the spring loaded members, the spring loaded members initially preventing the restraining member from moving but freeing the restraining member once depressed by the spindle.

27. An expandable sealing member comprising an elastomeric sealing material bonded to a generally annular support, the sealing member being expandable from a first unexpanded configuration to a second expanded configuration, wherein the elastomer is bonded to the support with said support in said expanded configuration and the sealing member is subsequently deformed into said unexpanded configuration.

28. A sealing member according to claim 27, wherein in said unexpanded configuration the sealing member is corrugated in the circumferential direction.

29. A sealing member according to claim 26, wherein the support is a washer.

30. An expandable seal, comprising an annular ring of sealing material which is in an unexpanded configuration is corrugated in the circumferential direction, said corrugations being substantially smoothed out to expand the seal.

31. A sealing member substantially as hereinbefore described with reference to the accompanying drawings.

32. A pipe fitting substantially as hereinbefore described, with reference to the accompanying drawings.

33. A method of installing a pipe fitting in an aperture in a container, substantially as hereinbefore described with reference to the accompanying drawings.

34. Apparatus for installing the pipe fitting in a aperture in a container wall, substantially as hereinbefore described with reference to the accompanying drawings.