// MOBILE FUME EXTRACTION UNITS
// INLINE / TOP LOADING FUME EXTRACTION
A large proportion of fume extraction units in the market today utilise what is known as a Top Loading system. There are those that argue it is a outdated principle, however in some circumstances where economy and small scale application is required it can offer a perfectly suitable solution. It does offer limits on application but should not be overlooked.
It is worth noting now that these styles of systems should not be used in conjunction with PVC laser processes. This is due to the HCL acid, which adheres and consolidates, over time it can drip onto the components below causing significant damage, and creating holes in the media, which can go un noticed....
That aside these systems are designed very simply, which makes them easy to use, maintain and economic where cost is a major factor in the decision making process.
They do not use a pre filter and rely on a HEPA filter and additional Chemical media as their only purification methods. This makes them ideal for systems where particulate matter is low such as: polymers (not PVC).
There major downfall lies in the lack of pre filter, causing the HEPA element to clog much faster especially where fumes leave an oily residue. The orientation of the filter does not help because particle build can sit in the pleats of the filter slowing the vacuum and at higher pressure causes filter ruptures.
// REVERSE AIRFLOW LASER FUME EXTRACTION
There are a few manufacturers now that are supplying reverse airflow systems to the market, BOFA, Purex to name a few. They encompass the full range of requirements as demanded by any laser user. Their simple airflow system works in a way to enhance the life of all internal parts of the purification system whilst maintaining 99.97% containment of laser fumes.
As air enters the unit it's forced to turn 90 degrees prior to being sucked through a pre filter. The theory is the turning, slows the air to the point where suspended particulate separates from the rest of the laser fume. This prolongs the life of the filters and improves airflow through the machine.
Many systems utilising reverse airflow also contain diffusers or perforated plates which control the airflow specifically through each filter, they match the airflow to the optimum filter efficiency of the filter media and inlet pump. This is designed to utilise all of the filter media, reducing the likelihood of ruptures.
The orientation of these systems also allow use with PVC laser processes because any HCL gas that is pulled through machine and consolidates within it, will drip to below, away from the mechanical and electrical components of the extractor.
