ConstaTwin® TR – Salt Spray + Humidity Test Chamber

Liebisch ConstaTwin® M-TR Test Chambers have been developed to perform both salt spray corrosion tests (such as DIN 50021, TS EN ISO 9227, ASTM B117, ASTM B368) and condensation humidity tests (such as DIN 50017, ISO 6270-2 -CH) in a single unit.

The chest-type chamber, which combines the features of ConstaSal® M-TR and ConstaCon® M-TR, is made entirely of glass-fiber-reinforced plastic. There are no metal components, heating units, or other elements inside the test chamber that could be affected by corrosion, ensuring long-term durability in corrosion testing. The ConstaTwin® M-TR test chambers are available in three standard sizes—400, 1000, and 2500 liters—based on the size and quantity of samples to be tested, but can also be custom-manufactured in 1200 and 3000 liters upon request. The top-loading design is particularly ideal for large-volume samples.

Standard models are equipped with a double-walled lid with high thermal insulation, enabling low-energy tests at 50°C and above, particularly suitable for copper chloride-acetic acid enhanced testing. Optionally, a transparent plexiglass lid can be added for clear visibility during testing. The 400 and 1000-liter models feature dual gas struts, while the 2500-liter model uses pneumatic pistons for lid support, ensuring safe and comfortable use for the operator.

The uniquely designed wide heating zones are located at the front and rear walls for salt spray testing and at the base for condensation humidity testing. These zones are fully thermally insulated, providing extremely homogeneous temperature distribution and excellent energy efficiency. Isolated from the corrosive test environment, these heating elements allow the unit to operate reliably for many years without requiring service.

The ConstaTwin® M-TR features separate outlets for exhaust air and drainage (automatically closed during humidity tests), ensuring optimal retention of salt mist within the chamber and preventing corrosion of other lab equipment. A removable strainer at the drain outlet prevents clogging by corrosion residues, enabling a reliable and uninterrupted testing environment.

Designed for 24/7 operation, ConstaTwin® M-TR is ideal for users who alternate between salt spray and humidity tests. While separate ConstaSal® M-TR and ConstaCon® M-TR units are recommended for continuous parallel testing, the ConstaTwin model is advantageous for users who collect samples and test them periodically, saving both lab space and cost.

The system includes a humidity tower with a constant level system for salt spray testing (S-System) and automatically draws water from a pressurized demineralized water line. The tower is equipped with high and low pressure warning sensors, and the inlet/outlet pressures are displayed on a manometer, allowing monitoring and control of humidification quality. For the condensation humidity system (K-System), the chamber features a standard constant water level control and also draws the necessary amount of water automatically from the pressurized demineralized water line.

The ConstaTwin® M-TR is extremely user-friendly. Depending on the applicable standard, the relevant temperatures for the test chamber and humidity tower are set using the three independent temperature controllers. The operator then selects either Salt Spray or Condensation Humidity mode. In salt spray mode, the spray nozzle pressure is adjusted to approximately 1 bar for optimal spray performance. A sophisticated digital dosing pump, which can be calibrated, precisely doses the saline solution to ensure required condensate formation. Unlike peristaltic pumps, it is not affected by tubing hardness and does not require monthly maintenance or parts replacement.

Before opening the lid at the end of a test or for sample inspection, the operator activates the ventilation button to flush salt mist out through the exhaust using pressurized air. Within a few minutes, the lid can be safely opened without spreading corrosive vapors in the lab.

Temperature settings for the test chamber and humidification tower are made using Liebisch temperature controllers. Each chamber size and test type has carefully tuned PID control parameters, ensuring temperature fluctuations are kept below ±1°C. The device can optionally be equipped with a cycle timer to stop the test automatically at the end of the programmed duration.

ConstaTwin® M-TR operates reliably for many years provided that high-quality air, demineralized water, and salt are used. However, periodic maintenance is recommended due to possible algae formation in the solution intake or contamination in the humidification tower caused by poor water or air quality. The standard maintenance interval is one year but can be extended to two years depending on environmental factors and regular operator cleaning. Maintenance is performed by the Kar Kimya service team based in Turkey.