Pre-filters, both wraps and panels, have the job of extending the life of the primary filter by capturing larger particulate, such as seeds, leaves, airborne fibers, etc. They are made of low-cost, relatively low efficiency materials, and are designed to be changed more often than primary filters–then thrown away.
Donaldson pre-filter wraps extend primary filter service life and add an additional stage of filtration on turbine air inlet static filter systems. These medium efficiency polyester pre-filters are designed to capture large particles, insects, seeds, and airborne fibres before they reach the filter cartridge.
- High-loft filter media has minimal effect on system ΔP.
- An integral tackifier in the media makes dirt particles cling to the fibres.
- Velcro closure has major benefits:
- It allows easier installation and removal around cylindrical and conical filters compared to other 'sock' styles of wrap.
- It allows you to create a snug fit without gaps – resulting in better performance.
The Velcro seam strip makes Donaldson pre-filter wraps easy to install and remove. Simply place the wrap around the filter element and seal the Velcro strip. To remove the wrap, simply undo the Velcro strip first and easily unwrap the filter element.
Specially designed for use in gas turbine inlet applications, these sturdy pre-filters can withstand up to 3"/ 76mm ΔP. Economical and easy to install, they sit in front of primary filter panels, providing a G4 first stage of filtration on large particulate and an effective way to extend the life of the primary filters. Pre-filters can be changed out without shutting down the turbine.
On all pre-filter styles, the air-leaving side of the filter media is bonded to a wire grid for stability, and the media is pleated to minimise the airflow resistance while maximizing the particle arestance and dust-holding capacity. Donaldson's pre-filter panel is made of long, coarse fibres, which are densely packed. The higher packing density enables good pleating, strength and good efficiency on large particulate.