Technical Description Teledyne API Ultrafine Particle Monitor - Model 651
58 07506C DCN6727
The Inlet Pressure reading is displayed on the Status screen on the
front-panel display.
Water Removal System
The Model 651 has a water separator and ejection system to remove
water from the vapor stream exiting the optics assembly. The water
separator condenses the water vapor and then the collected water is
ejected through the WATER EXHAUST port on the back panel and
away from the internal flow control orifices. A drain tube or bottle is
provided to allow the small amount of expelled water to be directed
away from the instrument to a suitable drain.
Counting Efficiency and Response Time of the Model 651 The Model 651 has a lower detection curve with a D50 of 7 nm. D50
is defined as the particle diameter at which 50% of particles are
detected. The curve fit shown in Figure 6-1 is based on testing of
three Ultrafine Particle monitors using sucrose particles generated
by TSI Model 3480 Electrospray Aerosol Generator and size-
classified with TSI Model 3080 Electrostatic Classifier and Model
3085 Nano Differential Mobility Analyzer (DMA). The counting
efficiency is calculated by comparing the Model 651 readings to TSI
Model 3068A Aerosol Electrometer readings.
The particle concentration measured by the particle counter is the
total number concentration of all particles that the Model 651 can
detect. This measurement provides no size differentiation and it is
not corrected using the Model 651 counting efficiency curve.
The Model 651 has a fast response time. T95, defined as the time it
takes for the instrument reading to reach 95% of a concentration
step change, is < 1.0 sec. Figure 6-2 shows the response time
curves, based on the average of three Ultrafine Particle monitors.