Teledyne 651 User Manual

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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. 
C o u n t i n g   E f f i c i e n c y   a n d   R e s p o n s e   T i m e   o f  
t h e   M o d e l   6 5 1  
The Model 651 has a lower detection curve with a D
50
 of 7 nm. D
50
 
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. T
95
, 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.