Disposable Permeation Tubes
KIN-TEK Trace Source™ Disposable Permeation Tubes :
The various types of tubes supplied are called HRT, SRT and SRT-2, EL-SRT or EL-SRT-2 and Wafer Tubes
HRT and SRT are simply different types of Teflon®, chosen for their respective permeation characteristics and inertness to the component compound.
HRT tubes are made of PTFE Teflon® and usually have a higher permeation rate than a comparable SRT tube. HRT are generally used for water, common solvents and lower vapor pressure compounds.
SRT and SRT-2 tubes are made of FEP Teflon® and are generally used for lower boiling compounds like hydrogen sulfide, sulfur dioxide, ammonia, etc., or to get lower emission rates from compounds that might normally be supplied in an HRT tube. The SRT-2 tubes have twice the membrane thickness of the SRT tubes and consequently about one half the emission rate.
If a tube has the prefix EL it means that tube has an impermeable reservoir for the component compound. For high permeation rate compounds like chlorine or carbonyl sulfide KIN-TEK always tries to use an EL tube so the customer will get reasonable operating life from the tube. A 5cm EL gives over twice the life of a standard tube, while the operating life of a 1cm EL tube will be many times longer than the life of a standard tube.
Wafer tubes are used for very low emission rates. They are basically an impermeable reservoir with permeation only from the ends. Generally, these are very long life tubes.