Glass tubes
Tubes are made of borosilicate glass which is very resistant to acids and to thermal shocks.
These bare tubes are used when Heat Recovery Process requests very low temperatures.
It is supplied with their associated devices to feet with the metallic part of the heat exchanger. Due to the type of material used, it is easily cleanable.
Focus
Steel parts exposed to flue gas are protected from corrosion with a PTFE coating.
Given that PTFE is used, these tubes are suitable from low temperatures to 250°C.