scope:

This TIP covers considerations for weld repairing new suction roll shells. It has been shown that suction rolls fail in service due to a variety of causes, one of which may be a discontinuity that is produced when a new shell is weld repaired.

This TIP serves two functions: (1) to acquaint the industry with factors of weld repairs in suction roll shells that may influence the shell service life, and (2) to provide a means whereby repairs in individual shells may be documented and later compared with shell performance.

It is beyond the scope of this TIP to provide criteria for rejection of new shells based on the size or quantity of flaws. Further, this TIP does not describe limits or manufacturing parameters on weld repairs that may affect the serviceability of the roll. However, it is recommended that the matter of weld repairs be negotiated between the purchaser and supplier when a new shell is ordered, and it may be desirable to reference this TIP in the agreement. Welding performed on in-service suction roll shells in an attempt to repair handling damage and fatigue cracks is also excluded from this TIP.