PTFE membrane is semi-porous layer of PTFE bonded to the surface of a filter. This membrane acts at a permanent dustcake, capturing incoming dust particles (i.e. particulate matter or PM 2.5) on the surface of the filter (surface filtration) as opposed to normal filters that require a thick layer of dust buildup (dustcake) to actually reach peak efficiency. This means that PTFE membrane bags can operate at peak collection efficiency from the moment they are installed, and do not need to be precoated. Overtime, the membrane also works against the dust penetrating deep into the depth of the filter fabric, which is the cause of filter blinding. For this reason, PTFE membrane bags often last considerably longer than standard filter bags and have a more consistent differential pressure over time.

Benefit of PTFE Membrane

On a standard bag dust builds up on the outside of the bag and creates what is known as the filter cake. The filter cake actually does the filtering while the bag fabric acts only as a support for the cake. When the bags are pulsed most of the filter cake releases and the build-up of dust begins again.

Over time however, some of the dust gets embedded deep into the bag fibers. Eventually, the bags will completely plug and need to be replaced.

Conversely, when PTFE is added to the bag it acts as the filter cake. Commonly known as Teflon. PTFE is used in many different applications from cookware to outerwear and more. When a PTFE membrane is laminated to a filter bag media it can enhance the performance of both the filter bag and the dust collection system. Let’s take a closer look at how a PTFE membrane works. If we zoom in on the PTFE membrane we can see that it is actually made out of tiny microscopic holes like Swiss cheese. The holes are large enough to allow air molecules and vapors to pass through but small enough to inhibit even the smallest dust particles from getting through.

Because the membrane keeps the dust on the surface of the bag particles never get embedded in the bag fibers and the bags will not fail from plugging up. Typically PTFE membrane bags wear out before they plug up. Usually lasting twice as long as standard bag. With twice the lifespan costly change-outs and plant shutdowns are cut in half reducing maintenance costs and increasing plant production. Since the bags are not gradually plugging up over time, PTFE bags give the additional benefit of providing more consistent airflow or suction from your dust collection system.

Because of the small pore size, PTFE membrane bags are up to eight times more efficient than a standard filter bag. This means it can cut out dust collector emissions by up to 800 percent.

Another advantage of PTFE membrane bags is that they clean easier because of their slick surface. This means less bag pulsing which means less wear and tear on the bags as well as the diaphragms and solenoid valves. It also means the system uses less compressed air resulting in reduced energy costs.

It can also improve performance when higher moisture levels or sticky dust are present. PTFE membrane can be added to any bag media and can replace standard bags and almost all applications. While there is a cost to add the membrane, the extra cost easily pays for itself by providing longer life, reduced maintenance cost, reduced wear and tear, and lower emissions.