Deep Basins / High Air Temperatures

Deep Basins and High Air Temperatures – Business as Usual for FLEXSIL® Membranes and AirRex® Headers

In deep tanks, diffusers are often exposed to very high air temperatures.From water depths of 6 m and more, the air temperature at the diffuser inlet typically exceeds 80 °C (176 °F). 

This elevated air temperature places special demands on the materials used in a diffusion system. High temperatures accelerate the aging of EPDM membranes and seals, and common PVC materials for pipework are only conditionally approved for use above 60 °C (140 °F). 
Thermoplastic membrane materials such as polyurethane (PU) are also limited in use at elevated temperatures—already restricted above 60 °C (140 °F) and typically unsuitable beyond about 80 °C (176 °F). 

In contrast, the OTT membrane material FLEXSIL® can be operated reliably and permanently at temperatures well above 100 °C (212 °F). OTT diffuser support bodies are made of a high-temperature-resistant PP plastic, certified up to 100 °C (212 °F). 
Since PVC pipework cannot be used reliably at high temperatures, we offer the OTT AirRex® piping system as a cost-effective and safe solution. AirRex® is made of glass-fiber-reinforced PP and remains extremely stable even in high-temperature applications. In addition, the AirRex® mounting system allows for expansion and contraction of pipe sections (see video "Expansion / Contraction of AirRex® at High Air Temperatures").

✱ We calculate the exact air temperature at the tank bottom, taking into account factors such as intake air temperature, heat from compression, and cooling in the submerged pipework section with high precision (Simulation link). 
Please contact us to discuss the selection of suitable materials for a reliable diffusion system in deep tanks.