Nomex Filter Bags Solutions for Dust Collection Systems

Nomex filter bags can normally operate continuously at temperatures up to 204°C (400°F). Short temperature spikes may be tolerated up to about 240°C (464°F), but they should not become part of normal operation. The actual limit depends on the media grade, exposure time, moisture, oxygen level, and chemical content of the gas. For longer bag life, keep the operating temperature stable and safely above the dew point.

Choose Nomex filter bags for hot, relatively dry, and abrasive dust collection. They work well when the normal operating temperature is between 150°C and 204°C, such as in asphalt plants, cement processing, foundries, and mineral plants. Nomex is also a practical choice when good mechanical strength and dimensional stability are required. Check the moisture and chemical conditions before making the final selection.

Nomex filter bags are not recommended for wet gas, frequent condensation, high humidity, or strong acidic and alkaline conditions. Moisture at elevated temperatures can damage meta-aramid fibers through hydrolysis and shorten bag life. They may also be unsuitable when the gas regularly exceeds the recommended temperature limit. PPS or PTFE filter bags may perform better in wet or corrosive flue gas, depending on oxygen level and operating temperature.

Nomex filter bags are a type of aramid filter bag, but the two terms are not exactly the same. Nomex® is a registered brand of meta-aramid fiber, while “aramid” describes a wider family of heat-resistant fibers. In industrial filtration, people often use “Nomex filter bag” to describe meta-aramid filter bags with similar performance. Aokai supplies meta-aramid filter bags designed for Nomex replacement applications.

Nomex filter bags are usually better suited to hot, dry, and abrasive dust, with continuous temperature resistance up to about 204°C. PPS filter bags normally operate at slightly lower temperatures but provide better resistance to hydrolysis, acids, and many chemical gases. PPS can be sensitive to high oxygen levels and strong oxidation. The correct choice depends on temperature, moisture, oxygen content, acid gases, dust abrasiveness, and expected bag life.

A properly selected Nomex filter bag can often last two to four years, but there is no fixed service life. Bag life depends on operating temperature, moisture, chemical exposure, dust abrasiveness, air-to-cloth ratio, cleaning pressure, cage condition, and installation quality. Frequent temperature spikes or condensation can cause much earlier failure. Reviewing used bags and operating records usually gives a more reliable estimate for a specific baghouse.

Yes, Aokai can manufacture replacement filter bags from an existing sample. We can check the bag dimensions, top and bottom construction, sewing pattern, snap band, reinforcement, and filter media structure. However, an old sample may have stretched, shrunk, or been chemically damaged during service. For better accuracy, please also provide the baghouse application, operating conditions, quantity, and any available drawing or original specification.