FLEXNORM® Membrane for D-REX® Disc Diffusers

FLEXNORM® Membrane
Article designation Article number A Outer diameter B Height Membrane C Inner diameter Membrane surface Weight
Material: EPDM 3344700001 Ø 276 mm / 10.87" 25,6 mm / 1.01" Ø 258 mm / 10.2" 0,055 m² / 0.59ft² ca. 220 g / 0.49lb
Tear propagation resistance ISO 34-1 A: ≥ 10 N/mm
Shore hardness: A 60 +/-5
Service temperature range: <= +80°C / 176°F

Pressure drop for FLEXNORM® membranes in new condition

The diagram above is a plot of maximum diffuser pressure drop (i.e. the pressure drop used for blower dimensioning) as a function of air throughput for different perforation grades. The pressure drop data applies for diffusers and membranes in new condition. The actual pressure drops across new diffusers/membranes will be lower and can vary in a given delivery lot within a window of 6 mbar (0.09 psi).

For example, a FLEXNORM® membrane used at an air throughput of 5 m³/h will have:

a maximum pressure drop (i.e. the pressure drop used in blower dimensioning) of: 28 mbar (0.41 psi) and a pressure drop window within the lot of e.g.: 21 – 27 mbar (0.31 – 0.39 psi).

The pressure drop across a diffuser or membrane can change in subsequent operation. The amount of change depends on the purity of the inlet air, composition of the wastewater treated, process chemicals used and their concentrations as well as the aeration process technology and process conditions.

Due to these many variable factors, we cannot specify the increase in pressure drop to be expected in actual operation in your WWTP. We will however gladly advise you in accordance with our experience and develop, using your input parameters, operating conditions and maintenance plans which reduce pressure drop build-up.