DOWN FLOW FILTERING

Think of a dust particle entering the space between filters . . . its velocity vector is 412 units long and is directed to the hopper. According to its mass, the particle is propelled per MV2 towards the hopper. This is a negative system, so the air surrounding the particle is being attracted to the filter at a velocity shown by a vector 1.5 units long. This is a correct representation and it illustrates the great advantage of vertically positioned filters, i.e., in the Smart-Flow design, dust particles by design are more compelled to bypass a filter than to enter it.

SETTLING CHAMBER
A settling chamber is a vessel having no air circulation. This can happen with a Smart-Flow™ dust collector. Since a one micron particle free falls only 5 in during one hour, it can be seen that any design which provides side or bottom entry is a dust storm hopper design providing massive re-entrainment. The only maintenance caution to a down flow hopper is that any air leakage at the dust outlet will carry fine dust back up to the filters. Most, but not all, slide gate valves would be likely offenders.

VENTURIS AND JETS
Venturis of good design should be used and never mounted within a filter. A jet not located remote enough from the venturi will not fill the venturi throat and will only partially clean the filter. There should be a two-way flow in the throat. Sometimes in a filter’s mounting, a rod will run across the filter opening between the orifice and the jet/venturi. Such a rod, even if it is only 1/8 in diameter, will severely reduce the effectiveness of the cleaning energy. Optimizing the orifice coefficient, its relative position to filter ID, jet divergence, compressed air energy level, and maximizing induced air are keys to jet performance/economy.

SYSTEM FLOW
It is important to make meaningful deductions in velocity wherever flow direction is changed. Many designs compromise the venturi. It must be small at the throat so that the jet can fill, yet large enough to have reasonable on-line velocities. Many designs fail here, but the Smart-Flow filter does not.

FILTERS
Smart-Flow filters are made with a cellulose media that is able to withstand water immersion and recover due to its high resin content – 22 percent by weight – and mechanical resilience. Filter installation requires no collector entry. There is a clean air duct (CAD) at the base of the housing which seals close to one wall, travels across the collector width, and enters the opposite wall terminating in the clean air plenum.

On top of each such clean air duct are three holes, which receive three venturi assemblies (venturi plus on-line bypass) in a housing. On top of this venturi housing is a “tube sheet” that represents both a pilot locator and support for filters. Two filters are set vertically on each venturi station. A filter clamping plate “holds” down the filters to make sure there is no by-pass of contaminants. This filter clamping plate is easily positioned for change out of the filters when needed.

Access through the door exposes the filters. As an example, 18 filters can be changed out in ten minutes, with dust exposure less than three minutes.

BOTTOM LINE
Smart-Flow filter technology is superior to other vertical and horizontal designs of filter technology. Eliminating dust, oil mist, molds, and other particulates from the air within a manufacturing or fabricating facility helps companies protect their workers from unhealthy air, which can cause sick building syndrome and other illnesses.

Indoor air is often two-to-five times more polluted than outdoor air and can be up to 1,000 times as dirty. The EPA estimates that most workers are exposed every day to indoor air contaminants than can lead to serious health problems, respiratory ailments, and fatigue, along with causing cancer and headaches. Efficient and effective point-of-source handling of smoke, fumes and oil mists can be a significant productivity tool, as well as a health, safety and environmental necessity.