TDS Seals

Types of Seals

Every clamp involves creating a pressure boundary to enclose and contain an active or potential leak. A pressure boundary is formed by the clamp via metal to metal interference fits between mating surfaces of the clamp and existing hardware or by using a variety of gasket materials at those surfaces. Once a pressure boundary is created, there are two methods of containing the leak. The void of a clamp can be filled with sealing compound. Alternatively, the void can be left empty and a perimeter seal created by pumping sealant into a groove machined into mating surfaces of the clamp sections and in the bores where the clamp seals on the existing hardware. This is done to prevent sealant from potentially contaminating the contents of the leaking system. It may also be used if there are concerns about sealant pressure in the void causing a thin wall pipe to collapse. Both methods can be combined for a single clamp if desired, the void fill generally serving as a backup in case the perimeter seal doesn't hold.

Void Fill

"Filling the void" refers to pumping sealant into the cavity of the clamp, which is the air space between the outside of the leaking hardware and the inside of the clamp.

Perimeter Seal (P.S.)

It is not always possible or desirable to fill the void on every clamp. There may be concern about contamination of the line service if sealant finds it's way into the line. Many sealants are very expensive and filling a large void can be cost prohibitive. The perimeter seal is formed by a groove running in one face of the clamp split line and in the bores. In a P.S. bore, there will be some kind of seal on either side of the sealant groove. This is usually tubing, packing, or crunch teeth. When the parts of the clamp come together, this groove is pumped, forming a sealant barrier between the parts and around the diameter of the closing surface in each bore of the clamp.