---
title: "PTFE-membrane filter bag"
description: "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."
canonical_url: "https://sylio.co/glossary/ptfe-membrane-filter-bag"
last_updated: "2026-06-28T02:29:25.179Z"
---

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](/glossary/differential-pressure-baghouse) over weeks and eventually causing [bag blinding](/glossary/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](/glossary/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](/glossary/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

- [Filter bag](/glossary/filter-bag)
- [P84 / Nomex / Ryton filter media](/glossary/p84-nomex-ryton-filter-media)
- [Bag blinding](/glossary/bag-blinding)
- [Sonic horn](/glossary/sonic-horn)