Baghouses
PTFE-membrane filter bag
Also known as PTFE membrane bag, ePTFE filter bag, Teflon membrane bag.
A PTFE-membrane filter bag carries a microporous expanded-polytetrafluoroethylene (ePTFE) membrane laminated to the outside surface of a base felt (usually polyester, P84 or PPS). Particulate is trapped on the membrane surface rather than within the depth of the felt — surface filtration, also called cake filtration on a membrane. Outlet particulate of below 1 mg/Nm³ is routinely achievable.
Why surface filtration changes the operating regime
In a conventional depth-filtration bag, particulate gradually loads into the felt itself, raising differential pressure over weeks and eventually causing bag blinding. A PTFE membrane prevents particulate ingress; cleaning is more complete because the entire cake sits on a non-stick surface; ΔP stabilises quickly after each pulse-jet cycle.
Where PTFE-membrane bags are specified
- Waste-to-energy baghouses with strict particulate limits
- Hazardous-waste incineration
- Pharmaceutical and food-grade applications
- Cement bypass baghouses
- Replacements for conventional bags facing tightened emission limits
Cleaning compatibility
PTFE-membrane bags tolerate sonic-horn cleaning without surface damage, provided horns are mounted to project sound across the bag rows rather than directly at any single bag at close range.
Related terms
Related terms
- Filter bagA filter bag is the cylindrical fabric sock that traps particulate inside a fabric filter. Media selection depends on temperature, gas chemistry, dust load and cleaning cycle.
- P84, Nomex and Ryton filter mediaP84 (polyimide), Nomex (aramid) and Ryton (PPS) are the three mainstream high-temperature synthetic filter media for baghouses. Each is matched to a different gas chemistry.
- Bag blindingBag blinding is the choking of filter-bag pores by dust embedded within the medium. It raises differential pressure permanently and is the leading cause of premature bag replacement.
- Sonic hornA sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.