Sop # 58
 
Title: Met One Laser Particle counter 

Purpose: This SOP introduces the user to to the particle
counter. The particle counter is used to take particle readings of the
level inside the cleanroom.

Precaution: Be very careful with this piece of equipment. The
sensor inside the counter is very fragile. Keep ALL chemicals
away from the particle counter. When not in use, the particle counter
will be kept inside the plastic storage case.

Procedure:  

Remove the particle counter and high pressure diffuser. If
temperature and relative humidity are to be measured, get the RH/Temp
probe out as well.

Remove the red cap from the inlet nozzle. The inlet nozzle is
located on top of the particle counter.

Insert the tube of the high pressure diffuser into the inlet
nozzle.

If needed, connect the RH/Temp probe to the back of the particle
counter. If the RH/Temp probe is not connected, these features will NOT
work.

Turn on the particle counter. The ON/OFF switch is located in the
back of the unit.

If the LO BATT LED is on, the internal battery is low and needs
recharging. Notify the LAB MANAGER.

Press the SELECT button. Observe the front panel around the seven
segment display. CNT displays the particle size range. The TIME and
DATE options are obvious. OPT allows access to other options. PER
indicates either the sample period or concentration of a volume of
air. HOLD indicates the time between count cycles. TEMP and Relative
Humidity (RH) display those values accordingly.

Choose the appropriate particle size to be measured. Press the
SELECT button until the LED is on PER. Press the PROG button. The LED
on the button should be illuminated. Press the UP/DOWN arrow keys to
select and appropriate particle size. When finished press PROG again.

Always use the particle counter in manual mode.

The time setting can be set to any length. To do this, press the
mode button until MANUAL mode is illuminated. Next press SELECT until
PER is illuminated. Press the PROG button. Set the time you wish to
use, (Time is in HH:MM:SS). Use the SELECT and UP/DOWN arrow keys to
move around. When finished, press the PROG button to exit.

To begin a particle count, press RUN/STOP. The LED next to COUNT
should be lit, showing it is counting particles. The LED display will
show the particle size being counted, and the number of particles
present.

When finished using the particle counter, remove the high pressure
diffuser from the unit. Place the red cap back on the inlet
nozzle. This keeps the inlet nozzle free of foreign material. Place
the particle counter back in the storage case.

There are several options that have not been covered in this short
SOP. For more information, please consult the Laser Particle Counter
Operating Guide.