Dust Monitor
CIHE calibrates and verifies the performance of dust monitoring instruments using best practice metrology methods. Our procedures are designed to maximize the repeatability, reproducibility, and accuracy of your dust monitoring instruments.
- Full calibration, testing, adjustment and cleaning to ASTM standards
- Calibration performed using ISO 12103-1 A1 test dust
- Calibrated using electronic engineering staff
CIHE uses a laboratory bench test chamber for dust monitor calibration, similar to that used by the manufacturers. Laboratory air is drawn into the chamber through a HEPA filter at the top, after which the aerosol is introduced and agitated to disperse it. An aluminum honeycomb sheet is located at the top to reduce turbulence as the air is drawn into the sampling chamber, with another one at the bottom. There is another HEPA filter at the bottom of the chamber to filter the dusty air before it is vented to the atmosphere.
The chamber houses a circular mesh carousel onto which samplers are placed. They rotate at one revolution every 6 min with a reciprocating action. Samplers are placed on the same circumference on the carousel and are be exposed to the same overall concentration of dust and local airflow conditions. In these tests, the samplers are placed on the lower chamber carousel, equally spaced and on the same circumference. An R&P 1400A TEOM provides the standard reference measurements during sampling. The probe of the TEOM is placed near the inlet of the test monitor.
For low dust concentrations, a TSI 3400 fluidized bed aerosol generator is used to feed Arizona Road Dust into the upper chamber. This produced an aerosol, which is highly dispersed and de-agglomerated before it enters the chamber. The aerosol is passed though a bipolar ion neutralizer before entering the chamber. This reduces the electrostatic charge on the aerosol; thereby minimizing losses inside the chamber caused by electrostatic attraction between the dust particles and the chamber walls. The extract flow is adjusted to give a velocity through the test chamber of a few cm/s.
