Work Tube Accessories

A wide range of work tube accessories is available when ordering a Carbolite furnace. To ensure the correct work tube accessories are supplied, please specify the tube furnace model (horizontal or vertical use), work tube dimensions (inner diameter, outer diameter and length) and operating temperature.
If you are not sure which accessories are the most suitable for your application, please consult our application experts.

Ceramic insulation plugs

Ceramic insulation plugs are designed to reduce heat loss from work tube ends and improve temperature uniformity. They are particularly helpful for vertical tubes and tubes with diameters greater than 25 mm.

Different insulation plugs are supplied for use with standard length work tubes (for use in air) and extended length work tubes (for use with modified atmosphere and vacuum). In vertical work tubes, insulation plug supports are required unless used with work tube end seals (see below).

Insulation plugs
Insulation plugs for vertical use

Work tube radiation shields

In extended work tubes radiation shields can be used as an alternative to insulation plugs. Specifically useful for dust free applications and with vacuum levels lower than 10-3 mbar.

Up to a maximum operating temperature of 1200 °C the shields are constructed from metal, and above this temperature from ceramic. In vertical work tubes, radiation shield supports are required unless used with work tube end seals (see below).

Ceramic radiation shields
Metal radiation shields

Work tube end seals

Work tube end seals are required to contain a modified atmosphere and for working with vacuum; vacuum levels of 10-6 mbar are possible. These end seals are manufactured from stainless steel and are for use with extended work tubes only. They are available to fit work tubes with the following outside diameters: 32, 46, 60, 70, 86, 100, 111, 150 and 165 mm. Other sizes are available at additional cost.

The following fittings are available for use with the end seals: blank seal, gas nozzle (inlet/ outlet), vacuum flanges (NW16, NW25 or NW40) and thermocouple glands (ø1.5 mm, 3 mm and 10 mm). Where the end seal diameter is large enough, combinations of the above fittings are possible, eg gas inlet/out nozzle + thermocouple gland.

The end seals are designed for use in combination with insulation plugs or radiation shields. Water cooled end seals are available on request. To accommodate the additional weight of end seals, tube supports are recommended (see below).

Gas nozzle (inlet/outlet)
NW40 vacuum flange
Thermocouple gland (1.5 mm)

Work tube supports

Tube supports have two functions:

  • to support extended work tubes
  • to support extended work tubes with the additional weight of end seals
The following two versions are available:

Optional hook and strap tube supports for STF & TZF 1500 & 1600 °C tube furnaces;
supplied as standard with the CTF & TZF 1700 and 1800 °C tube furnaces

Optional bench mounted tube supports for furnaces not using hook and strap supports