Mushroom flanged ceramic ferrules are designed to give protection to tube ends, tube plate and weld areas from the hot combustion products in boilers and other heat exchanger units. The temperatures of these areas will vary with boiler construction, pressure and firing intensity.

Tests carried out on modern packaged shell boilers by Midlands Research Station formerly of British Gas Corporation have shown the relationship between metal temperatures before fitting ferrules and temperature reductions achieved after fitting. This is shown in the graph overleaf. It is important to select the nearest size ferrule available to suit the boiler tube internal diameter in order to minimize any possible increase in windbox pressure.

A range of small flange ferrules are available for certain applications

Sizes listed in Small Flange!

Fixing cement is available for bedding in the ferrules, this is supplied in 1 litre tins and should be applied under the flange end only before pressing the ferrule into position. It is advisable to use a minimum amount of cement, sufficient to retain the ferrule in position and extrude for a short distance only into the cavity between ferrule and tube as shown in the installation diagram.

Average requirement: - 1 litre per 100 ferrules