How Purex fume extractors capture particles

Inside a labyrinth filterDifferent applications produce different types and different amounts of particulates and gases so a variety of filters and extractors is required. Purex machines deliver the correct combination of components to do the job correctly. These include:

  • Cabinets and coatings
  • Blowers
  • Reverse airflow
  • Pre-filters
  • Main filters

Blowers

Purex blowers have been designed to deliver high performance and long service life. Special features include:

  • High pressure development to give longer filter life and good extraction rates.
  • Compact size means Purex machines keep a small footprint.
  • Brushless design means they are continuously rated for 24/7 operation.
  • The speed of the blower is electronically adjusted which means "Flow Control' is possible.
  • Extended lifespan design.

Cabinets & Coatings

Purex offer a range of cabinet designs and sizes to ensure the correct one is specified for your application. PVC cabinets are coated internally to provide corrosion resistance.

Purex fume extraction range

- Cabinet Range -

Reverse Airflow

As soon as air is drawn into a Purex machine, its direction of flow is diverted through 90 degrees. This throws larger particles out of the air stream and into a collection tray or pre-filter bag, thus preventing them from entering the main filter and prematurely reducing its life span.

The Reverse Airflow system has an added benefit. When vapour is present in the extract air (e.g. from lasing PVC) it will condense into a liquid inside the filters and drip downwards. In other top loading fume extractors this liquid could potentially drip onto any electrics and motors below to cause a hazard. In Purex systems any liquid is collected in a tray or on an absorbant pad.

fume extraction air path

- Typical Layout -

Pre-filters

Pre-filters are used to collect larger particles over 1-3 microns to prevent them from prematurely blocking the main filters. Several options are available for processes that produce large quantities of dust; high capacity pre-filters, various types of bag filter and Cascade boxes.

Filter positions in some Purex fume extractors

- Examples of Filter Positions -

Unique Patented Filter TechnologyLabyrinth prefilter bag

The Labyrinth™ pre-filter is unique to Purex. It’s patented design presents more filter fibre surface area to the airflow than other filters on the market, allowing the filter to capture more particles before it becomes blocked.

The special material used has a graduated fibre density i.e. there are fewer fibres per unit area at the air entry to the fabric but the density increases towards the air exit layer. This allows the fibres to collect more dust before the filter becomes blocked. This means the filter lasts longer and is therefore more cost effective.

Main HEPA (High Efficiency Particle Air) filters

The filters used in Purex fume extractors have been designed to offer many unique features.

Purex HEPA and Carbon Filter

Filter Features:

  • Maximum airflow - The filter design allow the use of high pressure blowers to overcome the resistance to airflow through a filter for much longer as the filter begins to block. This means the filters last longer.
  • Guaranteed unburstable - By employing reinforcing.
  • Design - The size, design and production technique gives more filter media surface area than in many other filters, thus extending life span.
  • Maximum filtration - In independent tests, these filters remove 99.997% of all particles above 0.3 microns.
  • Flow equalisation plates - Help to distribute the airflow over the filter media and make the whole filter more robust.
  • Precise and rigid construction - Helps ensure that no fumes are allowed to pass around the filter and escape into the workplace.

Next page: Fume extraction filters for large particles »