During the salt fog cycle, salt solution is atomized into a fine mist. This is the same setup that normally would be used when running the ASTM B117 specification. Hot, humid air is created by bubbling compressed air (usually at 15 psi) through a tube (bubble tower, or humidifying tower) that is about 3/4 full of hot (usually 48oC / 118oF) deionized water.
Salt solution is moved from the 35-gallon solution holding tank to the nozzle by a gravity feed system using a float switch and plastic solenoid. When the hot humid air and the salt solution mix at the nozzle, it is atomized into a corrosive fog. The chamber is usually heated during this cycle at 35oC (95oF). by the chamber heaters. The chamber temperature is set by the user, and controlled by the MBPC. Fog distribution is controlled by the Uni-Fog dispersion system.
The salt solution can be replaced with other solutions to create a corrosive fog with differing properties.
A Humidity Cycle can be performed much like the Salt Fog Cycle with the difference of D.I. water being feed to the atomizer nozzle rather than Salt solution by the automated solenoid. The 35-gallon solution holding tank is filled with D.I. water for this test. This will create a 98% (+/- 2%) relative humidity condition.
During the Dwell Cycle, no action is taken by any of the chamber components.
Purge / Dry Cycle (Optional)
During the Purge/Dry Cycle, compressed air is directed into the chamber via the optional PURGE solenoid. This air then blows over an energized heater and out the chamber vent. The chamber temperature is set by the user, and controlled by the MBPC (microprocessor based programmable controller) . This dry cycle creates a low humidity state (~<30% RH) in the exposure zone of the chamber.
Solution Spray Cycle (Optional)
During the solution spray cycle, solution is taken from the standard 35 gallon holding tank (or if plumbed by the customer, the optional 60 gallon mix and storage tank) via a solution pump. This solution is driven into a spray bar header inside the exposure zone, and onto the parts by spray nozzles.