Ceramic withdrawable elements are used for heating of gas or liquid and also for melting of solids such as wax and lead. An advantage of these elements is that they can be removed for maintenance without having to drain the vessel they are heating.
The ceramic element is inserted into a pipe which is mounted into the container to be heated. The advantage of this heating method is that elements can be removed from the pipe without having to drain the container. This is of particular relevance when substances are frozen in the unheated state (e.g. wax).
By carefully selcting a suitable pipe material and thickness, a very durable heating system is obtained.
Installation of vertical ceramic withdrawable elements
The dimensions of the pipe must be such that there is a 1—2mm tolerance between pipe inner diameter and ceramic element outer diameter, allowing easy removal. An excessive tolerance will hinder heat transfer.
The pipe material is preferably a heat resistant stainless steel. Elements are usually mounted horizontally. For vertical mounting, elements must be specially constructed to prevent sagging of the heating spiral inside the element grooves.
It is good practice to allow access to the pipe from both ends, facilitating removal of debris when elements are replaced.
