Aerosolssample Conditioner (Asc); Optical Particle Sensor; Flow Sensor And Pump Control - Teledyne T640 User Manual

6.1.2.

AEROSOLSSAMPLE CONDITIONER (ASC)

6.1.3.

OPTICAL PARTICLE SENSOR

6.1.4.

FLOW SENSOR AND PUMP CONTROL

08354A DCN7303
The ASC removes volatile components (mainly water) of the aerosol to avoid
false particle size. Its operation includes an air sensor for measuring ambient
temperature and humidity in order to dynamically adjust the heating of the ASC
tube for moisture/humidity compensation.
The optical particle sensor is the main sensor in the instrument. This sensor
analyzes the particles, categorizing them by size and making the conversion to a
mass concentration.
The T640 operates using ambient and pressure compensated mass flow, for
accurate control of flow to actual volumetric conditions. The flow stream is
measured (main flow at 5 LPM for T640 and bypass at 11.67 for 640X Option),
and a feedback loop triggers the pump drive voltage adjustments to maintain a
constant flow (5 LPM in the T640, 16.67 LPM in the 640x Option).
The internal vacuum pump is a 24V DC pump controlled by a pulse-width
modulation (PWM) feedback control for consistently accurate flow to the sensor.
The external vacuum pump (640X Option only) uses either a 110-120 or 220-
240VAC pump. The bypass flow system is controlled by an ambient and pressure
compensated mass flow controller in combination with a pneumatic valve for
consistently accurate flow.
Teledyne API T640 PM Mass Monitor 64