If no special options or accessories are needed, there are four basic components to a corrugated metal hose: The tube (or hose itself), the braid, the braid collars, and the fittings. There may be times where an unbraided hose will work, but most applications require an assembly containing these four components. Let’s look at each of these components and their function as part of the total assembly, and how they all work together to provide value.
Corrugated metal hose assemblies are able to incorporate virtually any fitting that is able to be welded to the hose ends. Because of this, it is critical that the end fittings selected are appropriate for the intended application. Make sure the fittings are the right size, alloy, and pressure (designated by pipe schedule, tube gauge, pressure class, etc.) for the application, including any piping standards or specifications that must be met.
Braid collars are used to join the inner corrugated hose and the braid together during the cap welding process, where a TIG weld joins the hose, braid, and braid collar into the cap weld bead. A good cap weld becomes the base for the subsequent attachment weld. Additionally, the braid collar serves to isolate the last few corrugations from movement, as their cycle life may be compromised by the heat required to properly weld fittings to the hose. It is critical that the braid collars are sized properly in order to facilitate welding and to protect the last few corrugations from movement.