Types of Thermal Sprays

  • Electric arc wire (EAW) spraying
  • Flame spray powder or wire
  • Electric arc spraying
  • HVOF & HVAF
  • Plasma spraying
  • Vacuum plasma spray
  • Cold spray

Because of the various types of thermal spray applications and their effects on the operation of dust collectors, it is important to identify your specific thermal spray operation. Each process involves different shaped and sized particulate along with varying loads. Additionally, strict safety procedures need to be addressed as certain thermal spray operations can be explosive and/or flammable. Let Camfil APC’s expertise in this application help you to put in a safe dust removal system.

Safety Considerations

The potential for fire and explosion is very real when dealing with thermal spray and dust collection. It is imperative that Camfil APC be contacted for proper explosion venting and other safety concerns. Explosion vents, flame retardant cartridges and possibly spark traps all need to be addressed during the proposal phase of the sale.

Dust Collectors for Thermal Spray/Flame Spray

-Benefits of the Farr Gold Series® industrial dust collector:

  • High entry cross flow, inlet eliminates upward can velocities that can hold fine powder up in the filters reducing re-entrainment of the fine particles.
  • High efficiency filters stop 99.99% at 0.5µ of the dust! Special treated filter media repels the fine particle for lower pressure drop and long filter life.
  • Gold Cone® provides 25% more media for long service life.

Sizing Recommendations

With thermal spray applications, proper information gathering of the specific application is crucial since there are many different types of processes and material coatings, most all of which will react differently inside the dust collector. Although there are different powders used in plasma spray for example, the process results in generally spherical shaped particulate and consistent in size at around three microns making it fairly easy to capture.

Over the years, we tried several types of dust collection equipment on EAW spraying. However, all previous attempts at extended filter life (more than six months) failed until we installed a high efficiency "Farr Gold Series" cartridge collection system manufactured by Farr, Arkansas. At the time of this writing, the Farr Gold Series collector is still performing exceptionally well without a filter change after about a year and a half.

-David Drozd, Pamarco

With the Camfil APC Farr Gold Series collector, plasma spray and powder applications are generally sized at a conservative air-to-cloth (A/C) ratio with HemiPleat® fire retardant cartridges. Electric Arc Wire (EAW) Spray on the other hand has proven to be a real challenge. This dust is very fine (mostly sub-micron) and is inconsistent in shape. This seems to be true of the process itself no matter what type of wire is being used.

It is also important to note that certain hazardous powders and metals (such as nickle and chromium) will require safety after-filters when discharging to atmosphere. Please work with Camfil APC application engineers to insure the correct information is understood and proper sizing is accomplished.