Vibration Absorber

A vibration absorber sits between a compressor and the pipework to stop vibration travelling into the lines. Without one, the discharge line in particular works hardens, cracks at a braze joint, and eventually fails - usually within a year or two on a machine that runs continuously.

The VA series is a stainless steel braided hose with copper ends: the corrugated inner tube takes the movement, the braid takes the pressure and stops the tube from stretching. Thirteen sizes run from 3/8 inch to 4-1/8 inch, covering the line sizes used from small condensing units up to large parallel racks. Maximum working pressure ranges from 175 to 500 psig (about 1.2 to 3.4 MPa) depending on size, with burst pressures from 570 to 3,250 psig, so the working pressure falls as the diameter rises - which is the expected trade-off for a braided assembly.

The absorber should be mounted so that it takes the movement rather than resisting it: the usual arrangement is a bend of about 90 degrees in the absorber itself, installed in the direction that the pipe would otherwise move. Fitting one straight in a rigid line gives it nowhere to flex and shortens its life.

Two rules matter. First, size the absorber by line diameter, never by a smaller size for convenience - a reducer creates a pressure drop and a stress point. Second, do not use the absorber to correct a misalignment in the pipework; the assembly is designed for vibration, not for offset.

The braid should be inspected at service visits. A braid that has started to fray is a warning, not a cosmetic problem - the inner tube is already moving more than it should.