Special Purpose Industrial Fans
We categorize custom or “special purpose” industrial fans as those that are modified and applied for a specific function or application. They are standard centrifugal or axial designs that are factory modified to meet any application need with optional construction materials such as specialty steels, fiberglass, or PVC. Additionally, alterations to the fan wheel, inlet, outlet, housing, and supports are other changes typically instituted, to extend the fan life, without compromising performance. It’s not uncommon, when the product moves through a fan it accumulates on the fan blades or creates a clog, significantly altering the performance or causing fan failure. To counter this, the manufacturer made design change examples would include adding a “swing-out” wheel feature for cleaning, fitting cutting blades to a fan wheel for chopping paper trim, or providing a complete packaged “drop-in” ventilation fan assembly to facilitate easy installation.
Types of Special Purpose Industrial Fans
FRP Fans – Applicable to acid laden airstreams where heavy-duty construction leading to extended equipment life is a requirement. Fiberglass fans and blowers because of their versatility are widely used in wastewater, pulp & paper, and chemical plant environments.
PVC Fans – These are designed for corrosive environments that attack and degrade carbon steel construction. PVC is a common plastic material used to build fume exhaust fans.
High-Temperature Fans – Where temperatures in the airstream exceed 250 degrees F, fan designs need to change to accommodate the high operating temperatures without failure to bearings, metals, etc.
OEM Fans – Machine designs need an air mover that oftentimes needs to fit within tight space constraints.
Stainless Steel Fans – The need for corrosion resistance requires that we look beyond coated carbon steel and select the correct type of stainless, finish the surface treatment of the steel correctly and design for the gaseous constituents of the airstream or ambient environment.
There are also standard equipment designs that make a lot of sense for specific applications. These optional design features include:
Swing-out Fan Design
When fan wheels or impellers are subjected to a build-up of particulate, paint overspray, grease, or materials being conveyed, they need to be periodically inspected for cleaning. If there is a build-up of material on the fan wheel, it will cause imbalance and vibration resulting in failure of bearings and shaft. The “swing-out” feature affords minimal downtime when fan access is required, as the quick opening clamps allow immediate access to the interior of the fan for inspection and cleaning. Both centrifugal and axial fans are available with the optional “swing-out” feature.
Paper Trim Fans
When conveying paper and cardboard products, reducing their size with a chopper wheel, allows the materials to be conveyed without pipeline clogging.
When the need for moving large sections of cardboard, long continuous strings of paper, or plastic matrix scraps from punching processes, trim fans can be used to “chop up” and convey cardboard, paper, plastic, and other friable materials. These “chopper” fans reduce materials to a size that allows it to be pneumatically conveyed. The wheel construction is altered to a heavy-duty design with up to 1/2” thick blades and sharpened blade tips are sometimes added to the wheel. The housing interior surfaces are assembled continuously and snag-free with all interior nuts and bolts removed.
Dust Collector Fans
Mounting the fan on its inlet either in a vertical or horizontal plane, reduces the need for duct and reduces the fan footprint. These fans are referred to as horizontal mounted or flange mounted fans. This is a common design on dust collectors but can be applied to many more applications such as exhaust hoods, slant screens, wet wells, balers, product receivers, drop-out boxers, and even paint booths. These fans are typically arrangement 4, direct drive, and can be aluminum pressure blowers, or industrial exhausters with backwardly inclined or airfoil wheels. They are an ideal combination with variable frequency drives for airflow control.
Plug Fans
Plug fans are designed to fit into the wall of a cabinet or enclosure. They are available as Arrangement 9, belt-driven or Arrangement 4, direct-drive fans. The unhoused fan wheel uses the enclosure it exhausts from as the fan housing. Optional thickness insulated panels and inlet bells are available options. The plug fan design is seen often in oven exhaust, furnace fans, and custom air handlers.
Low Noise Fans
SysTech designed Lo-Noise™ Modules, typically large diameter propeller fans, direct drive, used to ventilate heat or gases, and coupled with silencers to systematically address compressor station ventilation for natural gas transportation facilities as well as all large buildings where a high number of air changes are required. Integral 90° weather hoods, silencers, and AMCA rated non-sparking construction along with hazardous duty motors are standard. Optional items utilized include agricultural/insect screens or filtered intakes, along with backdraft dampers or diffusers for airflow control. Multiple fans operating in unison normally are controlled via MCC incorporating LEL detectors and variable frequency drives.
