QUALITY

INSTRUMENTS

de México, S.A de C.V.®

Quality Instruments
Laboratory Licensed by ema to perform NRF-PEMEX  

corrosion and accelerated weathering tests. 

Laboratory Validated by Volkswagen to perform tests under the Standard 

TL 211 & TL 226.

QCT condensation tester chamber 

Humidity and temperature 

 

QCT chamber uses aggressive water to test the surface resistance of coatings and other materials. In a QCT chamber, humidity can be an invisible dew or a continuous condensation at high temperature. 

 

It can also be programmed to create a cyclic drying in order to release the osmotic pressure. QCT chamber accelerates the humidity attack by increasing the condensation temperature. 

Easy to use

QCT chamber does not require a special electric connection neither sanitary installations: just plug the unit and connect it to your ordinary tap water. 

 

How does the QCT chamber works: Condensation

Water in the lower part of the test chamber warms up to generate hot vapor. 

Vapor mixes with air and fills the chamber, thus creating a relative humidity of 100%. Since the test panels are the ceiling of the test chamber, panels cool with the external environmental air. 

The resulting temperature difference makes the vapor to condensate in lower part of the panels. This condensate is distilled water that is saturated of dissolved oxygen. 

 

A small amount of water vapor exits through the vapor dispersion channels on each side of the QCT unit.

 

Air continuously replaces the exiting water vapor, thus normalizing the air mix ratios. 

 

Condensation occurs first in the form of microscopic droplets. These droplets amalgamate to form larger drops until they finally drain away. 

 

Under constant conditions, this droplets cycle will repeat itself, provide a condensation excess in the testing surface. 

 

Constant condensation creates a strong osmotic pressure in the whole coating that tends to pull the pressure inside the coating. 

 

Pressure is released when the test specimen dries. One hour of drying eliminates almost all the water of a 23 hours condensation cycle. 

 

These drying periods represent many of the service conditions. The reciprocal transition from wet to dry is much more important than the drying time duration. When the material is dry, little deterioration occurs. Normally, a drying time from one to two hours is enough for the cyclic operation.