FLEXNORM® Tubular Membranes For 63 mm O.D. Diffuser Bodies

Material specification

FLEXNORM® is an ethylene propylene diene monomer (EPDM) elastomer

Colour Black
Shore hardness DIN 53505 A 45 +/-5
Maximum service temperature 80 °C / 176°F
Tear propagation resistance ISO 34-1 A ≥ 10 N/mm

Dimensions

Dimensions / FLEXNORM® tubular membranes
Article designation Article number A Active membrane length B Overall length D Inner diameter Active membrane surface Material Colour
MB FLEXNORM® 460 3400460000 460mm / 18.11" 520mm / 20.47" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,08m² / 0.86ft² EPDM black
MB FLEXNORM® 500 3400500000 500mm / 19.69" 560mm / 22.05" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,08m² / 0.86ft² EPDM black
MB FLEXNORM® 542 3400542000 542mm / 21.34" 602mm / 23.70" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,09m² / 0.97ft² EPDM black
MB FLEXNORM® 720 3400650000 720mm / 28.35" 780mm / 30.71" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,11m² / 1.2"ft² EPDM black
MB FLEXNORM® 750 3400750000 750 mm / 29.53" 810 mm / 31.89 Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,12 m² / 1.3ft² EPDM black
MB FLEXNORM® 770 3400770000 770 mm / 30.31" 830 mm / 32.68" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,12m² / 1.3ft² EPDM black
MB FLEXNORM® 875 3400875000 875 mm / 34.45" 935 mm / 36.81 Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,14m² / 1.5ft² EPDM black
MB FLEXNORM® 950 3401000001 950 mm / 37.40" 1010 mm / 39.76" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,16m² / 1.7ft² EPDM black
MB FLEXNORM® 1000 3401000000 1000 mm / 39.37" 1060 mm / 41.73" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,16m² / 1.7ft² EPDM black
MB FLEXNORM® 1109 3401109000 1109 mm / 43.66" 1169 mm / 46.02" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,18m² / 1.9ft² EPDM black
MB FLEXNORM® 1146 3401146000 1146 mm / 45.12" 1206 mm / 47.48" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,19m² / 2.0ft² EPDM black
MB FLEXNORM® 1300 3401300000 1300 mm / 51.18" 1360 mm / 53.54" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,20m² / 2.2ft² EPDM black
MB FLEXNORM® 1920 3401108000 1920 mm / 75.59" 1980 mm / 77.95" Ø 65,0mm - 66,0mm / 2.56" - 2.60" 0,35 m² / 3.8ft² EPDM black

Slit pattern and slit size

The tubular membrane is perforated by a specially configured pattern of slits. It has no perforation at its 6 o’clock and 12 o’clock positions as well as on both ends. The slit size is dimensioned in accordance with the specific diffuser type and application at hand. Slit sizes are available in the following range: 

0,6mm / 0.024"

1,0mm / 0.039"

1,2mm / 0.047"

1,4mm / 0.055"

2,0 mm / 0.079"

Pressure drop vs. throughput for FLEXNORM® membranes in new condition with different perforation grades

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 1.4 mm thick FLEXNORM® membrane used at an air throughput of 15 m³/h will have:

a maximum pressure drop (i.e. the pressure drop used in blower dimensioning) of: 60 mbar (0.87 psi) and a pressure drop window within the lot of e.g.: 50 – 56 mbar (0.72 – 0.81 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.