Airflow Rate Errors; Isolating And Repairing Leaks; Chapter 6: Troubleshooting - Spectris Particle Measuring Systems Airnet II 4-CH Operation Manual

Chapter 6 : Troubleshooting

Airflow Rate Errors

As a result of the performance check procedure (see Chapter 5 Maintenance and
Performance Checks), the flow rate at the sensor's inlet should be the following:
•
0.1 CFM for models 201-4, 301-4, 501-4: 0.085 - 0.115 CFM (± 5 %)
•
1.0 CFM for models 310-4, 510-4: 0.85 -1.15 CFM (± 5 %)
A flow rate error greater than 15 % (±5%) indicates that maintenance is required.
Low flow could be due to an obstructed orifice, leaks or insufficient vacuum.
A minimum of 12 inches of Hg vacuum is required at the Airnet II 4-Channel particle
sensor's critical orifice to provide the required sample flow rate. If the flow rate is still
low after determining that there is sufficient vacuum, perform the following
procedure.

Isolating and Repairing Leaks

To isolate and repair leaks:
1. Remove the top and bottom halves of the instrument.
2. Run samples.
3. While a sample is running, use a bulb syringe to blow a small amount of smoke
around the possible leak paths and watch for an increase in the number of
counts.
The following locations are possible leak paths:
•
•
•
•
•
•
4. If a leak is suspected around the inlet jet, remove the jet and O-ring, clean
lubricate and/or replace parts.
5. Reassemble the unit.
6. If a leak is suspected around the laser diode or photodiode, contact Particle
Measuring Systems for assistance.
6-2
Where the inlet jet meets the body of the sample block
Around the laser diode
Around the photodiode
Around the laser window
Around the beam dump
Around the mirror plug
Airnet® II 4-Channel Particle Sensors Operations Manual
Airflow Rate Errors