Abstract: An insulated pipework system comprises an outer sleeve, an inner flow pipe and one or more evacuated volumes in the space therebetween defined by annular plugs of a setting polymeric composition such as epoxy resin or a syntactic foam, typically at regular intervals along the length of the pipeline. The epoxy resins (for example) are ideally of sufficient rigidity to allow effective transfer of longitudinal forces between the inner and outer pipes. Thus, the evacuated volumes will themselves be annular. Other plugs of different orientation (for example longitudinal) could be included to subdivide the evacuated volumes further. The plugs allow the space between the pipes to be partitioned so that air can be evacuated from the sections so formed to provide the vacuum that acts as the insulating layer. Also, the plugs replace the need for bulkheads in that the partitioning of the inter-pipe space provides the desired water-stopping means.

Abstract: The application describes a method of manufacturing a double-walled pipe structure, comprising the steps of providing a pair of inner flow pipe and an outer sleeve pipe around each thereof, providing an insulating material within each annular space therebetween, joining the two inner flow pipes in an end-to-end relationship with the outer sleeve pipes spaced apart, and sliding a cover section into place over the gap between the sleeve pipes, the cover section comprising a length of tube with a longitudinal split therealong, wherein prior to sliding, the cover section is opened by enlarging the split thereby to provide an inner diameter greater than the outer diameter of the sleeve pipe, and after sliding the cover section is compressed such that its inner diameter is less than the outer diameter of the sleeve pipe.

Abstract: A gasket for noting an annular space between two pipes comprises an annular elastomeric member (10) having a concave formation on at least one longitudinal end face, compression members (20, 22) adjacent the longitudinal end faces and connected via a plurality of securing means (30) adapted to urge the compression members (20, 22) together, the compression member or members (20, 22) adjacent a concave formation on the elastomeric member (10) including a corresponding convex formation. The elastomeric member (10) can also include a concave formation on at least one radial face (12, 14), in which the gasket can further include at least one (preferably elastomeric) filler member in that concave formation, on the radial (12, 14).

Abstract: Two embodiments of insulated pipework system are described. The first comprises an outer sleeve, an inner flow pipe and insulating material within the space therebetween and is characterised by the use of a longitudinally compressed elastomeric member in the space between the inner and outer pipes as the primary means for transferring longitudinal forces between the inner and outer pipes. The second comprises an outer sleeve pipe, an inner flow pipe, an insulating material within the space therebetween, other than hollow alumina-silicate microspheres, wherein a longitudinally compressed elastomeric member is provided at intervals in the space between the inner and outer pipes. Compression of the elastomeric member is preferably by way of rigid plates on either side thereof which compress an the elastomeric member. For example, bolts can be passed through bores in the plates and elastomeric member and tightened thereby to compress the said member.