For proper sealing, the sample needs to rest on top of the sample support tube with the sealing material between. The diameter of the sample should therefore be approximately the same as the outer diameter of the support tube. For example, if you have 20 mm samples, you will therefore need a 20mmØ sample support tube. The sealing gaskets for this tube size have outer diameter 18.5 mm.

We have also sample support tubes with outer diameter 10, 12, 15 and 24 mm. They are supplied with their own size of sealing gaskets.

If sealing is not required, a 20mmØ sample support tube can be used also for samples smaller than 20 mm. To prevent the sample from falling down into the support tube, you should place an alumina support plate between the support tube and the sample. Such plates are included in both normal system and extensive system.

Standard support tube diameter for our systems is 20 mm as it gives suitable space both on the inside of the tube and between the tube and the enclosing tube for fitting gas tubes, electrode contacts and thermocouples.