Emergency Repair

All existing expansion joints are candidates for our services and existing parts inventory may be used wherever technically possible in delivering the required solution. SFP have performed thousands of successful repairs in the fi eld all over the world saving process operators substantial cost and ensuring safe operation of their plant. Our experience and track record is unique, no other manufacturer can claim levels of success or fi eld competence approaching those of SFP.

SFP have two well-proven repair techniques suited to different operational needs:

• On Line / Over Size Clamshell
• Off Line / Same Size Clamshell

On Line / Over Size Clamshell

This repair technique can be applied to expansion joins on operating plant that are either suspected of likely failure prior to the next planned maintenance period or have already developed a leak. The repair is normally be made at the full operating temperature and fl ow of the process system, eliminating the need for an expensive shut down.

Avoiding an unplanned shut down offers a considerable cost benefi t to the operator whilst reducing operational risk and enhancing operational safety.

• What is a clamshell?

  A clamshell is an additional bellows that has been cut longitudinally into two or more pieces to allow it to be fi tted over the existing bellows on the expansion joint. The bellows are mounted on standoff rings welded to the expansion joint and welded longitudinally to form a complete, functional expansion joint.

• How is a clamshell designed?

  A clamshell is designed for the full rated operating condition of the plant wherever possible. The only constraints on this are the capability of the existing expansion joint hardware (hinges, tie rods, gimbals etc) or piping system to safely accept the additional pressure thrust loads. The additional pressure thrust results form the pressurisation of the larger diameter of the clamshell bellows. A rating verifi cation is undertaken by SFP on every clamshell designed. If the system cannot accept the loads at full rated operating conditions the maximum allowable operating pressure is advised to the customer.

• How fast is the repair delivered?

  Hardware can normally be manufactured within 48 hours and a fi eld crew despatched to site within 24 hours of the repair being requested. If a field survey has been undertaken by SFP the hardware lead-time can be further reduced, as we will have details of the joint on file.

• Can repair kits be designed in advance?

  Yes. SFP recommend that clamshell kits be purchased in advance for process critical expansion joints that are known to be nearing the end of their safe operational lifetime. By purchasing the key components in advanced costs can be reduced and the engineering / rating of the clamshell optimised further.

Off Line / Same Size Clamshell

A same size clamshell is designed to be a close fit over the existing bellows. The welding of the clamshell in close proximity to the existing bellows means that the clamshell must be fitted with the process unit off line and cool.

• What are the advantages of a same size clamshell?

  There is no additional pressure thrust imposed be the expansion joint on the piping system. If the original bellows is removed it is also possible to provide a spring rate very similar to the original design value. The same size clamshell is lower cost than the oversize and its installation will not be impeded by existing joint hardware.

• What are the disadvantages of a same size clamshell?

  The clamshell must be fi tted with the plant shut down. Holding a same size clamshell as an emergency spare relies on a planned plant shutdown occurring in advance of a bellows failure.

SFP Site Service Solutions are deigned to reduce both cost and operational risk and ensure your maintenance investment delivers best value over many years of successful and trouble free operation.