Filtrex

Advances in high rate industrial filtration have dramatically broadened equipment choices. Historically, two types have been prominent. Sand, which needs a relatively large area to house the system and conventional pressure and vacuum diatomite systems, with their slurry feeders, labor intensive slucing and frequent filter aid changes.

Here's how it works. Diatomaceous earth is applied to the surface of the elements inside the tank. Billions of minute passageways are formed through the media which are capable of trapping solids as small as one micron. When the accumulated dirt causes the filter flow to diminish, active regeneration begins.

Industrial fluid filtration ... a new era.

Both types consumed large quantities of filtered effluent, and thermal and electrical energy at times of regular cleaning maintenance.

EXTENDING THE FILTER CYCLE

Regardless of the system type the search for methods to extend filter cycles has been ongoing. While low application rates have helped, operating gains have been offset by higher equipment costs and the need for greater housing space.

The efficient answer lies in regenerative filtration.

ACTIVE REGENERATION... CLEARLY THE BETTER CHOICE Today's active regenerative diatomaecous earth filters provide the effective solution to extended filter cycles...while offering the benefits of reduced space, saving in fluid and filter aid all without a maintenance penalty.

It should be noted there are two approaches to filter cake regeneration...active and passive. Both use diatomaceous earth as the filter media. But that's where the similarity ends.

ACTIVE REGENERATION... FAST, EFFICIENT, ECONOMICAL Active regeneration, pioneered by Filtrex, removes solids down to one micron. It provides consistently sparkling, clear effluent. Process streams using active regeneration are unquestionably cleaner and brighter than those using conventional filters or those depending on a passive regeneration process.

To begin with, Filtrex's Flex-Tube filter element by virtue of its patented construction, maintains a variable pore opening. This allows the elements to respond to changes in ambient filter pressures... a necessary characteristic for true and complete regeneration.

First a unique down-up bump stroke causes an enlargement of the filter element pores, powerfully propelling the filter cake from the elements. Elapsed time...15 seconds. Next, a high velocity mixing chamber within the filter tank recognizes the filter media. Finally the media is randomly reapplied to the elements restoring flow and pressure to their original values. No process fluid has been lost...and the filter is back on line. Total elapsed time: five minutes.

Active regeneration is automatically initiated whenever needed without operator interaction.

PASSIVE REGENERATION... LENGTHY, UNCONTROLLED PROCESS

Passively regenerated filters use diatomite filter aid in much the same fashion as inactive regeneration. However they lack a positive mechanism for removing the filter cake from the internal elements. Instead, during regeneration, the filter is taken out of service and gravity is used to slough the cake from the elements. Elapsed time: one to four hours. Finally, a resumption of flow causes a mixing of the filter aid and a reapplication on the filter elements.

While passive regeneration does extend the filter cycle, it deprives the process of filtration for extended periods, seriously affecting turnover. Even when performed during off-use hours, passive regeneration adversely affects recovery following peak loads. What's more, the filter elements in a passive regenerative filter are woven...this means the pore size is permanently fixed. Eventually, the repeated on-and-off cycling of the passive process partially blinds the opening resulting in increased maintenance.