High temperature resistant filter Nomex Needle Felt Nomex Filter bag for steel melting furnace applied

NOMEX Needle Felt offer one of the best total economies in a filtration system because of higher air to cloth ratios, higher temperature capability, and a long wear life.

Properties:

1) Performs at high temperatures

NOMEX Needle Felt can be used continuously at operating temperatures up to 218°C (425°F) , and can handle higher temperature surges. However, to optimize bag wear life, continuous temperatures of 204°C (400°F) and lower with minimum temperature surges are recommended.

2) Resists flexing and abrasion

Flex resistance of NOMEX Needle Felt at room temperature is good, about equal to that of polyester fibers; after aging at temperatures of 121°C (250°F) and above its toughness if excellent. Nomex should give more than three times the wear life of polyester at 121°C (250°F) and above.

3) Effect of moisture

NOMEX Needle Felt performs well at high operating temperatures with normal amounts of moisture. The wear life projections in the below graphs were developed using 6-10% H20. Higher levels of moisture and temperature shorten wear life. When operating in high moisture environments it would be worthwhile to investigate reduction of temperature to reduce wear life. For example with 20% H20, operating hours could be increased from 2,300 hours to 35,000 hours (15X) by reducing the temperature from 204°C (400°F) to 148°C (300°F).

4) Resists Chemicals

NOMEX Needle Felt aramid fiber resists attacks by mild acids, mild alkalis, and most hydrocarbons. In addition customers report it to be unaffected by fluorine compounds in gas effluent from metallurgical and rock processing operations. In acid environments, evaluation of NOMEX Needle Felt should be made to ensure that the fiber will perform acceptably before insulation. NOMEX Needle Felt is an acid environment, at temperatures above the dew point, will outperform polyester. Temperatures above the dew point should be maintained to minimize chemical attack on NOMEX Needle Felt and the equipment. The system should be warmed before putting on stream and dried before being shut down to minimize chemical attack. To optimize bad life when acid gases are present in the gas stream, the lowest operating temperature that is safely above the dew point should be used. Higher temperatures expedite chemical attack.

5) Dimensional Stability

NOMEX Needle Felt is one of the most dimensionally stable fibers available. Fibers of NOMEX® properly manufactured and finished, should neither stretch nor shrink over 2% when operated at temperatures up to 218°C (425°F).

6) High temperatures

The most effective use of NOMEX Needle Felt aramid is in high efficiency filtering systems where effluent temperatures are above 250°F or in systems with surges over 250°F. In hot gas filtration systems, fabrics of NOMEX Needle Felt require less filter area, for equal gas volume and efficiencies, than fiber glass.

The technical data of Nomex needled felt