EPDM Diffuser Membranes

SSI Aeration’s EPDM Disc Membranes and Tube Membranes field-tested for longevity and reliability

Our EPDM membranes have been field tested in municipal and industrial applications worldwide with excellent results, both with fine bubble disc diffusers and fine bubble tube diffusers.    We manufacture all EPDM diffuser membranes in our own factory with new injection molding machines.  We also perforate our own parts in house.

SSI EPDM Membrane Features and Benefits:

  • Low plasticizer content – this means that the membrane will last longer before it hardens, shrinks or breaks.   Low concentrations of plasticizer are chemically stable in vulcanized rubber, however, when you add too much, it migrates out in tiny droplets over time, resulting in membrane weight loss and failure.   It is important that SSI produces its own membranes. Outsource vendors have an incentive to use more plasticizer because it makes the rubber more free flowing and easier to process.


  • Much higher than industry standard tensile strength and elongation at break.   Nobody expects a membrane to stretch to 700% of its resting length, however it is important.  The higher the elongation, the more expensive the rubber gum, the better it snaps back to close the slits, and the less it creeps or permanently deforms over time.


  • We use scheduled obsolescence to determine the end of life of our membrane tooling.  When you have just a few molds and fixtures, you may be able to follow a different protocol, but when you are as big as SSI, you need a different approach to quality control.   We count the cycles on our molds and perforation knives, and we change them on a schedule.   An old mold makes parts with uneven thickness, and old knives make rough slits that may not bubble uniformly across the part.


  • Excellent oxygen transfer efficiency and longevity in many municipal and industrial applications for over 20 years.  Few companies have remained in the founders’ hands for so long.  SSI has had the good fortune to keep our turnover very low, resulting in very knowledgeable people at all levels of the company.


  • SSI membranes are built to provide stable performance with minimal shrinkage, cracking/crazing or creep/stretching over time.


  • Often the difference between two brands is the headloss.   SSI has designed its diffuser cross sectional thickness, uniformity and perforation knives to provide the lowest possible dynamic wet pressure (DWP) across our membranes.  Please visit SSI CurveGen(TM) for more data on a specific product.


  • We have innovated lower cost ways to deliver oxygen to your process through innovation. The single molded diffuser was developed at SSI, which uses the same high quality membrane as our conventional products, but in an economical package.  Have a look at our EC series tube and disc diffusers.


  • SSI’s premium membranes are available as direct replacements for SSI and as an upgrade for most other brands.  In many cases, we can also provide diffuser installation services.


  • Besides EPDM, SSI also produces PTFE coated EPDM, Silicone, and Polyurethane membranes.


To learn more about the worldwide choice for Custom-Molded EPDM Membranes, fill out the form below and one of our experts will contact you.

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