Teledyne 651 operation manual W i t W o r k s, Physical Features

Product Overview Teledyne API Ultrafine Particle Monitor - Model 651

PARAMETER

SPECIFICATION

Physical Features

Front panel	Display, sample inlet, LED particle indicator
Back panel	Power connector, USB, Ethernet, RS-232, BNC
	output, fan, water fill connector, pump exhaust
	port, fill bottle and bracket
HxDxW	20.3 x 48.3 x 30.5 cm (8 x 19 x 12 inches)
Weight	9.9 Kg (22 lbs)

H o w i t W o r k s

The Ultrafine Particle Monitor - Model 651 is designed to measure the concentration of airborne particles. The Model 651 draws in an air sample and counts the number of particles in that sample to provide a particle concentration value that is displayed as the number of particles detected per cubic centimeter of sampled air.

The Model 651 utilizes a patented* laminar-flow, water-based condensation growth technique. Particles which are too small (nanometer scale) to scatter enough light to be detected by conventional optics are grown to a larger size by condensing water on them. In this instrument, an air sample is continuously drawn through the inlet via an external pump and a portion of the flow is sent to the exhaust as transport flow. The stream of aerosol particles is uninterrupted and follows a laminar flow path from the sample inlet to the optical detector.

The Model 651 particle counting process is as follows:

∙The aerosol enters the sample inlet.

∙In the conditioner, the aerosol sample stream is saturated with water vapor and then temperature-equilibrated.

∙The sample passes to a growth tube where the wetted walls (composed of a porous medium) are heated to raise the vapor pressure. The high diffusivity of the water vapor allows the vapor to reach the center of the sample stream at a faster rate than the thermal diffusivity of the vapor can equilibrate to the higher temperatures near the walls—creating a supersaturated condition along the radius of the flow stream. These unstable conditions facilitate water condensation on the sample particles.

∙Particles that are larger than the detection limit of the Model 651’s minimum critical particle size act as condensation nuclei as they pass up the growth tube.

*US Patent No. 6,712,881, Aerosol Dynamics Inc., Drs. Susanne V. Hering and Mark Stolzenburg.

20 07506C DCN6727