What Are High Volume Air Samplers?

High volume air samplers are instruments that are designed to collect particulate matter using a high volume vacuum motor.  This instruments have various options for collecting various sizes of particulate matter.

TSP or Total Suspended Particulate samplers are designed to collect total suspend airborne particulate.  These samplers are also commonly refereed to as lead samplers.  TSP samplers collect all particulate matter onto an 8″ x 10″ piece of glass fiber filter paper.

Particulate matter  less than 10 micrometers in diameter. These particulate are small that they can get into the lungs, potentially causing serious health problems. Ten micrometers is smaller than the width of a single human hair.

 Particles less than 2.5 micrometers in diameter are called “fine” particles. These particles are so small they can be detected only with an electron microscope. Sources of fine particles include all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial process

Polyurethane foam or PUF samplers get their name from the polyurethane foam collection substrates that it uses to collect volatile organic compounds.  PUF samplers are commonly used for pesticide sampling or collecting other VOC’s.

What is the difference between brush style and brushless style motors?

Brush style motors use a set of carbon brushes to conduct current.  Brushed motors are low cost but require routine motor brush changes.

Brushless motors do not use motor brushes to conduct current which eliminates any spark or exhaust debris.  These motor use electronics and permanent magnets to conduct current.  Brushless motors require no maintenance but the come at a higher cost.

Volumetric Flow Controlled (VFC) vs. Mass Flow Controlled (MFC).

The VFC or Volumetric Flow Controller is a critical orifice used to determine the amount of gas that passes through the orifice.  The device is calibrated to allow a set flow rate.  The motor attached to the device operates at full speed pulling enough air through the device to achieve  desired flow rate.
There is no way for a user to adjust the flow rate on Volumetric Flow Controlled systems.

MFC or Mass Flow Controlled systems use a hot wire anemometer to control the flow.  The hot wire anemometer or flow probe is inserted into the flow channel to detect changes in thermal mass.  As the filter loads with particulate the thermal mass changes and the mass flow controller adjust the motor speed to maintain the set flow rate.