Dry Lint Filters
TEA's F-80 Top Discharge Dry Lint Filter in a
rooftop application
Stainless Steel Dry Type Lint Filter
Thermal Engineering offers the most efficient dry type lint filter available. The growing use of dry type lint filters (about 70% of the market and growing) versus the wet type is proving to be the preference of the laundry industry.
The major advantages of the TEA dry type lint filter are:
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Our exclusive spiral vortex forces lint and solids to outside of cone leaving a large center area of screen relatively free of lint. Large amounts of lint actually spiral down the cone without ever touching the screen resulting in lowest on-line pressure drop of any dry type lint filter available. |
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TEA filter screens are only made of stainless steel. Drum tight tensioning totally eliminates screen flutter, a major cause of screen failure. The tangential direction of the inlet air effectively re-directs solid objects away from the screen preventing most punctures and holes. |
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Horizontally mounted screens have proven to be superior during the blow down cleaning cycle because gravity assists in moving the lint away from the screen. Shorter air blow down cycles can be used which will significantly reduce air consumption . |
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The all metal construction with four cross-braced legs is the strongest, most durable design available today. |
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The 304 stainless steel housing is totally maintenance free. Fiberglass units, however, deteriorate in the weather and require periodic painting to prevent deterioration from ultra-violet radiation. |
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Maintenance is simplicity itself. The filter screen and the air blow down rotor are the only items that may ever need servicing. |
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The clean, dry, light weight lint is far simpler to handle and dispose of than the wet, soggy mess coming from wet type filters. |
Performance
The real key to effective lint collection is to select a unit which will not noticeably compromise the performance of the dryer. Exhaust air back pressure will influence the drying times of a dryer more than all other deficiencies combined.
Thermal Engineering’s lint filter has more net open area than any other filter available. Combined with its exclusive vortex action, owners are experiencing about 20% faster drying times than with their previously installed fiberglass units.
Safety
A dryer initiated lint fire can ignite all of the lint in the exhaust ducting and lint filter. TEA’s stainless steel housings are conservatively rated at 1650 degrees Fahrenheit for 10 minutes and will not support combustion. All internal components except for gaskets are of metal construction and will normally not be damaged. The fire control system (optional) is set to trigger at 350° F. This is considerably higher than the normal operating range of dryers and allows a more reasonable spread between operation temperatures and hazardous conditions.
Fiberglass lint filters will burn when ignited! Even when fire resistance is claimed, and reference to the ASTM-E-84 "tunnel fire test" is used, this test in no way matches the actual operating conditions that the fiberglass lint filters are subject to. This is why more dry type lint filters are being constructed of metal. At the present time, only two major suppliers are still supplying units of fiberglass construction.
Designing a Lint Filter:
The Plenum Vs. The Spiral Vortex
All dry type lint filters use a fine mesh screen in the air stream for collecting the lint, thus preventing its discharge into the atmosphere. As a result of lint build-up on the screen, back pressure severely affects the performance of the dryer during a given drying cycle by restricting air flow. Even though all dry type lint filters have a blow down cycle, the lint build-up pattern on the screen during the drying cycle is a critical factor in the lint filter design.
Dry type lint filters have traditionally been designed with inlet air plenums to distribute an even layer of lint on the entire filter screen during operation. The deposited lint acts as an even finer filter collecting the smallest particles of lint very efficiently, in fact, too efficiently. Air flow is quite sensitive to restrictions and an inducted back pressure will result in an immediate reduction of dryer performance.
Thermal Engineering’s exclusive "Spiral Vortex" design controls the way lint is deposited on the screen. By moving the inlet pipe to the extreme outside diameter of the lint filter, the inlet chamber is no longer a distribution plenum. The lint laden air entering the lint filter is immediately forced into a constantly reducing circular flow path – a "Spiral Vortex". The circular flow path produces an extremely high centrifugal force on the lint particles (even micron sized) forcing them to the outside wall where they increase in size by combining with other particles. Surface friction of the cone (housing) slows down the particles where they either drop out into a lint collecting bag or deposit on the outer edge of the screen. The relatively lint free center of the screen allows dryer exhaust air to pass through the screen with little pressure drop.
Numerous field installations of TEA lint filters have verified the lint collecting pattern and have resulted in drying time reductions up to 20% over competitive dry type lint collectors.