GB2177774A

GB2177774A - Protecting pipe ends

Info

Publication number: GB2177774A
Application number: GB8518010A
Authority: GB
Inventors: John Wilson Munn
Original assignee: DPM OFFSHORE Ltd
Current assignee: DPM OFFSHORE Ltd
Priority date: 1985-07-17
Filing date: 1985-07-17
Publication date: 1987-01-28
Also published as: GB8518010D0

Abstract

A protective cover for the end of a drill pipe (10) or the like comprises a steel shell (14) and ring (16) welded to form an annular member (17), and a foamed polyurethane (18). In Figure 1 the polyurethane (18) is shaped to engage a screw-thread (12) of the pipe (10) to retain the cover. An alternative retaining means is also described (Fig. 2). <IMAGE>

Description

SPECIFICATION Protecting pipe ends This invention relates to protective covers for the ends of lengths of pipe or tubular members, and is particularly but not exclusively, of use with oilfield casing and drill pipe and pipe connectors. All such items will be referred to herein for convenience as "pipe".

Such pipe lengths are formed with special connector ends and it is important that these are not damaged during transit and handling.

It is known to provide protective covers which remain on the pipe ends until immediately before use. However the known protective covers are relatively expensive to manufacture, are cumbersome in use, and are prone to corrosion.

Accordingly, an object of the present invention is to provide improved protective covers.

The invention provides a protective cover for the end of a pipe, comprising an annular metal sleeve having a front face transverse to the pipe axis and a side face parallel to the pipe axis, and an elastomeric plastics material disposed in the angle between said faces and formed to a shape complementary to the pipe end.

In one form, for use with threaded pipe ends, said plastics material has a complementary thread form by which the cover is secured to the pipe end. in another form, the cover is provided with a plurality of circumferentially spaced locking devices which can be moved inwardly to engage formations in the pipe end; each locking device suitably comprises a plate member welded to said side face and a socket-head screw member in threaded engagement with the plate member, the arrangement being such that when engaged with the pipe end the top of the screw member is substantially flush with the plate member.

From another aspect, the invention provides a method of making a protective cover for the end of a pipe, comprising providing a positive pattern conforming to the shape of at least the end of the pipe, positioning adjacent each other the pattern and an annular metal sleeve having a front face transverse to the pipe axis and a side face parallel to the pipe axis, injecting a plastics composition, preferably a foamable composition, between the pattern and the metal sleeve to produce a shape complementary to the pipe end.

The plastics material is suitably a two-part elastomeric polyurethane.

Embodiments of the invention will now be described, by way of example, with reference to the drawings, in which: Figure 1 is a partial cross-section through a cover forming one embodiment and an associated pattern; Figure la is a scrap side view of part of Fig. 1; and Figure 2 is a partial cross-section through a cover forming a second embodiment and an associated pipe connector.

Referring to Fig. 1, a pipe has its end section 10 formed with a tapered male thread 12 for engagement with a mating female thread in an adjacent pipe (not shown) as is conventional in the oil industry. The cover of the present invention comprises a mild steel shell 14 and ring 16 welded to form an annular member 17 of L-shaped cross-section. The space between this member 17 and the pipe end 10 is filled with a foamed polyurethane 18 which is shaped to correspond exactly with the surface of the pipe.

This may be achieved by positioning the annular member 17 in the correct relationship, by suitable jig means, to the end section 10 or to a pattern having a surface contour exactly corresponding to that of the pipe end.

The end section 10 or corresponding pattern is first coated with a release agent. A twopart foamable polyurethane material is then mixed and introduced into the intervening space and allowed to expand and cure, in the process being bonded to the annular member 17. Thereafter the cover can be removed by unscrewing. The cover can then be screwed onto and unscrewed from any matching end section.

As shown in Fig. 1A, the other edge of the shell 14 is slit to form a tongue 20, which can be bent to engage a slot 22 (Fig. 1) on the pipe and thus prevent unscrewing during transit.

Fig. 2 shows the invention applied to a cover for a non-screw-threaded pipe connector 26 of known type, which has a split ring 28 seated in a circumferential groove 30. The cover comprises parts 14, 16 and 18 similar to those of Fig. 1 and produced in the same manner. The cover is held in position by a number of circumferentially spaced locking devices of which one is seen in Fig. 2. The locking device comprises a steel flanged boss 32 in threaded engagement with a tapped hole in the shell 14. The boss 32 is internally threaded to receive a threaded brass plug 34 with a recessed socket head. This can be screwed in to engage behind the split ring 28 as shown, and unscrewed to clear the split ring 28 to allow the cover to be removed.

The locking device when engaged is substantially flush with the shell 14, i.e. there is no significant projection to become caught on obstructions. The materials used resist seizure by corrosion.

The covers of the present invention give a high degree of protection and impact resistance, while being inexpensive to manufacture and resistant to degradation by water, oil and drilling fluids.

There are no significant projections from the protection after installation, due to the design, and the materials used obviate corrosion between screwed boss and brass locking plug.

Claims

1. A protective cover for the end of a pipe, comprising an annular metal sleeve having a front face transverse to the pipe axis and a side face parallel to the pipe axis, and an elastomeric plastics material disposed in the angle between said faces and formed to a shape complementary to the pipe end.

2. A cover according to claim 1, for use with threaded pipe ends, in which said plastics material has a complementary thread form by which the cover is secured to the pipe end.

3. A cover according to claim 1, in which the cover is provided with a plurality of circumferentially spaced locking devices which can be moved inwardly to engage formations in the pipe end;

4. A cover according to claim 3, in which each locking device suitably comprises a plate member welded to said side face and a socket-head screw member in threaded engagement with the plate member, the arrangement being such that when engaged with the pipe end the top of the screw member is substantially flush with the plate member.

5. A method of making a protective cover for the end of a pipe, comprising providing a positive pattern conforming to the shape of at ieast the end of the pipe positioning adjacent each other the pattern and an annular metal sleeve having a front face transverse to the pipe axis and a side face parallel to the pipe axis, injecting a plastics composition, preferably a foamable composition, between the pattern and the metal sleeve to produce a shape complementary to the pipe end.

6. The method of claim 5, or the cover of any of claims 1 to 4, in which said plastics material is a two-part elastomeric polyurethane.

7. A protective cover for the end of a pipe, substantially as herein described with reference to and as illustrated in Figs. 1 and la or Fig. 2 of the drawings.