A Winger Inc. Company
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Why use a Scrim?


The cleaning mechanism on the RF filter is substantially different from "pulse-jet" and "reverse-air" mechanisms used by other dust filters. The type of recommended bag is different also.

The RF filter uses a large volume of 7.5 - 8 PSI air to create a shock wave of air that is strong enough to propagate to the bottom of the bag with considerable force. (see “How does the RF Cleaning Work”)

The filter bag must be "stiff" so the RF generated air-shock can be transmitted through the bag and knock the dust off.

If the filter bag is not stiff, then energy of the shock is absorbed by the bag as it stretches; only a fraction of the energy is transmitted to the dust; only a fraction of the dust gets knocked off. Bag life is decreased many times.

With non-stiff bags the cleaning is inadequate: the bags will "blind up", the pressure drop rises, and the bags must be replaced more often.

Scrim analogy: Think of ice on a sheet of plywood. You hit the other side with a mallet; the shock energy is transmitted by the stiff plywood and knocks the ice off. In contrast think of a large sheet of rubber with ice on one side; hit it with a mallet; the rubber absorbs much of the shock by stretching; subsequently there is less shock energy to knock off the ice.

How to make a stiff filter bag? Use a scrim.

Our OEM RF bags have a scrim - a netting made of polyester thread. The fine denier threads, which make up the felt, are needled through this scrim. This felt costs significantly more than self-supported felt. Bags made with scrim felt will give you longer bag life and lower emissions from the finer denier. Self-supported felt stretches 5-10 times more than a felt with scrim and self-supported felt uses coarser fibers so emissions are higher.

The RF Collector was engineered to use scrim bags to provide cleaner air for employees and for our environment, ultimately lowering “installed” costs.

If you have a problem with static buildup in your baghouse, Day Filters. offers various options to solve this condition. Contact Us and we will perform a thorough risk evaluation at your facility to identify and eliminate factors that could contribute to an explosion. This is one of the mandatory requirements set forth in the NFPA standards for the handling of combustible dusts, which are now being enforced by OSHA and local authorities.

Winger also offers equipment for the process industries
Feeder Systems
Day Filters™
A Winger Inc. Company
5500 Lakeland Ave N. Crystal, MN 55429
Phone: 763-795-9779
Fax: 763-795-9889

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