Heating tube with large heat capacity - has cemented sand composition inside metal tube with axial heting wire inside insulating tube

摘要

The heating tube consists of an outer metal tube enclosing an electrically insulating tube which in turn encloses an axial heating wire. The wire is supported inside the insulating tube by spacers with radial arms. The ends of the tube are sealed with plugs of the same material as the inner tube. This material consists of 62% fine sand, 25% cement and 13% fire clay. The length of the tube is determined by the dimensions and resistance of the wire and the power required. The large heat capacity of the structure allows intermittent electrical supply while retaining approx., constant heating.