Cincinnati Sub-Zero Tech Note
December 2018, MARIETTA, GA ~
One of the most common options required in an environmental test chamber is humidity. Humidity can have a dramatic effect on materials of all varieties of chemical make-up. Unfortunately, even with the commonplace use of humidity as a variable in environmental testing, the quality of the water supply used is often overlooked.
Water often has a variety of minerals and can even have chemicals added before it arrives via a public water supply. These impurities, over time, can cause damage to a test chamber in the form of blocked atomizer nozzles, corrosion, and even leaks.
CSZ offers a variety of options to help prevent impurities from harming your environmental humidity chamber include using de-ionized water (DI), or de-ionized water filtration systems, and reverse osmosis systems (RO).
Specific filtration needs should be discussed if a water source has organic, free chlorine and chloramines, or phosphate complexes present. Occasionally checking the resistivity of the water supply can help ensure that no new contaminants are introduced. If you are unsure if this is necessary, please contact CSZ. We have the ability to test a water supply for resistivity levels to ensure that they are appropriate for your humidity test chamber.
The amount of water passing through a filtration system will be what determines how long each system will operate before needing maintenance. CSZ reach-in humidity chambers can typically use between 0.5 GPH and 3 GPH during normal operation while larger chambers can use much more water. Other variables including the test RH, the size of the chamber, size of the heater in kW, and how many and how often temperature and humidity cycles run; all have an impact on how much water is used and consequently how long the filtration system will operate between maintenance windows.
Other critical factors which could affect the performance of your humidity test chamber include maintaining proper water pressure and keeping the humidity sensor clean. Water pressures lower than 25 PSIG for generator/ boiler systems and 10 PSIG for atomizing systems must be maintained via a water regulator. Pressure which exceeds these levels could cause failure of the top or bottom cap of the DI filter and allow the system to leak.
Humidity sensors should be regularly cleaned and calibrated to ensure proper readings and longevity of the sensor itself. It is recommended to clean the sensor tip with alcohol and dry using a dry chamber running at 250°F for 10 minutes.
For additional information on CSZ Temperature and Humidity chambers, please click here