Composite repair clamps

Composite clamp repairs have been the subject of research in the past few years (Sum and Leong, 2014 Shamsuddoha et al., 2013a,b). The most recent advancement in repair clamps is the composite repair clamp, ProAssure Clamp. This is a fibre-reinforced polymer matrix composite repair solution equivalent to a metal mechanical clamp. This repair method presents the aforementioned advantages associated with composites over metallic clamps, with the repair taking a form known to operators. 

A two-part, room temperature or warm curing adhesive paste, very suitable for composite structural repair schemes where normal heating and clamping facilities during cure are not available. 

Unlike the case of a composite clamp which is manufactured under shop-floor conditions that allow close control of the curing process, overwrap repairs are applied and cured in the field. Hence, it is not always practical to replicate laboratory cure conditions and the surface preparation of the substrate that have been used to determine the properties and performance of the overwrap repair system. To this end, a good understanding of the cure behaviour of the overwrap composite material and the composite—substrate interface properties is essential to ensure that repairs are properly applied and the acceptable performance is achieved in the field. 

Figures 12.14—12.17 show applications of the ProAssure products. It can be seen that overwrap repairs can be successfully applied on the platform, in the splash zone as well as in the sea. Obviously the complexity increases as repairs move from dry to wet and subsea environments. This is not only restricted to application of the composite laminate but also to related activities such as removal of existing coatings and surface preparation, as well as additional requirements such as the need for scaffolding, absailers and/or a service barge. A similar scenario applies to the clamp repair solution, which is generally advantageous over the overwrap repair method in cases of deeper...

Djukic, L.P., Sum, W.S., Leong, K.H., Leong, A.Y.L., Hillier, W.D., Eccleshall, T.W., Falzon, P.J., 2014. A novel high pressure composite clamp for pipeline repair. In Element Oilfield Engineering with Polymers 2014. 

This chapter details current industry codes for composite repair and case studies of both of the composite repair methods mentioned above through the use of two recently developed and field-tested repair systems, ProAssure Clamp and ProAssure Wrap Extreme. 

Figure 12.17 Installing a composite repair clamp onto a pipe with a through-wall defect.

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