WesTech continuous rotary drum filters provide a wide range of liquid-solids separation for many types of industrial processing flowsheets. They offer the operating flexibility to handle dewatering, washing and clarification applications, or a combination of these processes. WesTech drum filters are available with drums up to 13.5 ft diameter and 36 ft in length and are built to customer specifications.
Vacuum Drum Filter Designs Include:
• Scraper Discharge is the most common drum filter discharge. After dewatering, the cake is removed from the filter cloth by a scraper blade just prior to the resubmergence of the drum. The scraper serves mainly as a deflector to direct the cake, dislodged by an air blowback, into the discharge chute.
• Precoat Discharge is best applied to processes which have relatively low concentrations of solids or produce filter cakes which effectively blind the filter media.
• Roll Discharge is especially good for thin, sticky cakes which have the unique property of sticking to themselves. The filter cake on the drum is pressed against a discharge roll packed with filter cake so that the thin cake is pulled or peeled from the drum. Solids are removed from the discharge roll with a knife blade.
• String Discharge best applies to thin cakes and materials that are unstable and if disturbed too much will change from a solid to a liquid. Most generally applied in the starch and pharmaceutical industries. A system of endless strings or wires spaced about 0.5 in apart pass around the filter drum but are separated tangentially from the drum at the point of cake discharge. The strings return to the drum surface guided by two rollers with the cake separating from the strings as they pass over the rollers.
• Belt Discharge offers the ability to discharge filter cakes and wash both sides of the filter cloth with each drum rotation. Westech Belt Discharge Drum Filters offer the ability to discharge filter cakes and wash the filter media with each drum rotation. Many applications using this type of filter produce thin, sticky and wet filter cakes which are not easily discharged without the aid of a discharge roll.
• Belt discharge vacuum filter applications:
• Metal Hydroxide Waste
• Gypsum (FDG)
• Municipal Waste
• Lime Softening Sludge
• Potato Waste
• Corn Gluten
• Aluminum
Belt discharge vacuum filter applications:
• Metal Hydroxide Waste
• Gypsum (FDG)
• Municipal Waste
• Lime Softening Sludge
• Potato Waste
• Corn Gluten
• Aluminum
Precoat Vacuum Filters are for continuous clarification of liquids from slurries containing 50 to 5,000 ppm of solids when only very thin unacceptable cakes would form on other filters and where perfect clarity is required. Precoat filters are also the equipment of choice in cases where materials quickly blind filter cloths or where the solids are very slimy, sticky or slow filtering.
The precoat filter requires a sacrificial filter bed, consisting of filter aid, to retain solids on the surface. Typical filtration cycles are one to ten days. Prior to each filtration cycle, the feed slurry is introduced and trapped in the outer surface of the precoat, where it is removed by a progressively advancing doctor knife which trims a thin layer of solids plus precoat. When the precoat has been cut to a pre-defined minimum thickness, the filter is taken out of service, washed and freshly precoated in a relatively short period of time.
Precoat discharge vacuum filters applications
• Oily Wastes
• Corn Syrup
• Dissolved Air Flotation Wastes
• Lime Mud
• Chemical Wastes
• Polishing
• Food and Beverage
• Poultry
• Tank Wash
Benefits of the WesTech Precoat Filter :
• High capacity due to high speeds and minimal pressure drop.
• Drier cake due to low submergence
• Thinner precoat cuts due to superior knife advance system
and longer lasting knife.
• Low maintenance
• Low power requirements
• Easy to precoat with no cake cracking. High speed drum
precludes cake dry out.
• Sloughing off of cake at beginning of precoat cycle does not
occur, since there are no individual drum sections.
• Cake expansion and shrinkage is limited because vacuum is
constant around the drum.
• Easy precoat formation. Adaptive to a wide range of solids.
• Higher filtration rate per square foot of area.
Contact WesTech to discuss the specifics of your application. WesTech Vacuum Drum Filters offer a wide latitude of process flexibility in Liquid-Solids Separation.
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