Moulded or machined pipe bowl - comprises mixture of microscopic glass bubbles and heat-resistant binder with outer wall including protective coating

摘要

The pipe bowl is formed by a moulded or machined mixture of microscopic bubbles of glass, silica, ceramic or other material and a suitable heat-resisting binder. The density of the glass bubbles can be between 0.10 and 0.30, their mean diameter being between 10 and 300 microns or more. A hydraulic binder can be used such as plaster or cement, particularly magnesium cement. The proportion of bubbles and binder can be such as to give a bowl density between 0.5 or less and more than 1, typically 0.7, and the outer wall can be protected by a decorative coating such as varnish or silicate.