Self-Support vs. Scrip Support

Advancements in technology have now made possible a fiber supported felt that is equal to and, in most cases, has better performance characteristics than traditional scrim supported felts.  Here is additional information and specifications.

  1. The absence of a scrim means that all of the fibers in the felt are available for filtration.  Scrims are so tightly produced that they cannot contribute to normal filtration.
  2. Scrims can blind easily if dust penetrates into the felt.  This can lead to premature failure of the bags from the resulting high pressure differential.
  3. The absence of a tight scrim means that air can flow more freely, allowing higher velocity or lower pressure drop.
  4. Scrims affect the flexing characteristics of the felt, so their removal can improve some aspects of the media’s behavior, including allowing easier pulse cleaning.
  5. Needling tends to weaken scrims, whereas this process strengthens fibers.  In most cases this leads to higher overall media strengths.
  6. In general, fiber supported felts are less expensive than those containing scrims, due to the high cost of producing scrims.

In terms of physical characteristics, the products compare as follows for a 16 Opsy polyester felt:

Fiber Supported Scrim Supported
Mullen Burst 540 PSIG 400 PSIG
Permeability 40 CFM 40 CFM
Average lbs of force at failure (Longitudinal)

 

236.5

 

223.7

Average lbs. of force at failure (Lateral)

 

413.3

 

291.6