1. Cyclones A CENTRIFUGAL FORCE IN AIR SAMPLING
A Presentation by
SKC Inc.

2. SIZE-SELECTIVE SAMPLING TRADITIONAL CRITERIA FOR PARTICULATE MATTER
Total
Respirable

3. SIZE-SELECTIVE SAMPLING NEW INTERNATIONAL CRITERIA
Inhalable
Thoracic
Respirable

4. RELATIVE SIZE OF PARTICLES
Respirable:
4 micron
Thoracic:
10 micron
Inhalable:
100 micron
RESPIRABLE
THORACIC
INHALABLE

5. CYCLONES
Traditional workplace samplers for respirable particulate matter
Named for the rotation of air within the chamber
Function on the same principle as a centrifuge
Use rapid circulation of air to separate particles according to their aerodynamic diameter

6. WHY USE A CYCLONE?
Some sampling methods require collection of the respirable fraction of particulates. Respirable particulates are:
Smaller than 10 microns in diameter
Penetrate deep into the gas exchange region of the lung
Cyclones enable collection of the respirable fraction only
Collecting larger, non-respirable particulates would inflate results of sample, overestimating exposure

7. WHY USE A CYCLONE ? Small particles are whirled up into the filter
Cyclones separate larger, non-respirable particles from smaller, respirable particles
Small particles are whirled up into the filter
Large particles fall into the red “grit pot”

8. 50% CUT-POINT: A PERFORMANCE SPECIFICATION
The 50% cut-point is often used to describe the performance of size selective samplers
It is the particle size that the device can collect with 50% efficiency
Particles smaller than the 50% cut-point are collected with an efficiency greater than 50%.
Larger particles are collected with an efficiency less than 50%

9. 50% CUT-POINT ON THE COLLECTION EFFICIENCY CURVE
50% cut point is 4 µm

10. THE NEW INTERNATIONAL CRITERIA
Specifies a 50% cut-point of 4 μm for respirable dust samplers, including cyclones
This criteria has been adopted by ACGIH, ISO, CEN, and many agencies worldwide

11. CYCLONE PERFORMANCE There are a variety of cyclones on the market
Each cyclone has different operating specifications and performance criteria
All cyclones are not created equal!
Be sure you know the flow rate specified to achieve the desired cut-point before using a cyclone

12. CYCLONES AVAILABLE FROM SKC
Aluminum Cyclone
Meets ACGIH/ISO/CEN respirable curve at
2.5 L/min
Eliminates adverse electrostatic effects
Specified in NIOSH Method 7500 for silica and 0600 for respirable particulates

13. CYCLONES AVAILABLE FROM SKC
GS-3 Cyclone
Conductive plastic
Safe for underground mine use
Eliminates adverse electrostatic effects
Meets ACGIH/ISO/CEN respirable curve at
2.75 L/min

14. CYCLONES AVAILABLE FROM SKC
GS-1 Cyclone
Constructed of same conductive plastic material as GS-3
Single inlet version to match specifications of Dorr-Oliver
Meets ACGIH/ISO/CEN respirable curve at
2.0 L/min

15. CYCLONES AVAILABLE FROM SKC LTD.
UK Plastic Cyclone
Meets ACGIH/ISO/CEN respirable curve at
2.2 L/min
Leak-tested plastic construction
Features a “snap together “ cassette
Static dissipating

16. TIPS FOR SAMPLING WITH SKC ALUMINUM OR GS CYCLONES
Prepare 3-piece filter cassette
Place cyclone into middle ring
Calibrate the pump with sampler in line
Take sample at specified flow rate
Remove filter and cyclone from sample train
Recap and send filter to lab
Clean cyclone before reuse

17. TIPS FOR CALIBRATION SKC Aluminum Cyclone (Cat. No. 225-01-01/2)
Has a aluminum calibration chamber that fits over the cyclone and allows standard tubing to be attached for connection to the pump calibrator
The chamber fits both the 25-mm and the 37-mm aluminum cyclones
(Cat. No )

18. TIPS FOR CALIBRATION SKC Calibration Jar (Cat. No. 225-111/112)
Very large jars are not recommended when calibrating with the piston-style primary calibrators like the BIOS Defender. The dead volume in the jar can affect the rise/fall of the piston causing the readings to be erroneously low!

19. TIPS FOR CALIBRATION SKC Calibration Jar (Cat. No. 225-111/112)
Use the smallest jar possible to contain the cyclone/filter assembly. SKC offers a calibration jar suitable for the SKC GS Cyclone (Cat. No )

20. TIPS FOR CALIBRATION
Another option is the “jarless” calibration method using piston-style primary calibrators
Attach the pump only to the suction port and the cyclone/filter assembly to the other port on the calibrator. This will create the same pressure drop as the sampling train assembled in the field.

21. SAMPLING WITH A CYCLONE
Ensure the grit pot is attached during sampling otherwise, there is no size selection
Use the sampling rate specified by the manufacturer to achieve the desired cut-point:
SKC Aluminum: 2.5 L/min
SKC GS: 2.75 L/min
SKC UK: 2.2 L/min
Dorr-Oliver: 1.7 L/min

22. POST-SAMPLE CLEANING
After sampling, clean all parts of the cyclone with mild soapy water
Don’t forget to clean the grit pot!
Dry the cyclone
Air or blow-dry
Wipe with a dust-free tissue or wipe with an isopropyl alcohol moistened pad.
Caution: Do not use strong solvents to clean plastic cyclones

23. A CENTRIFUGAL FORCE IN AIR SAMPLING
CYCLONES
A CENTRIFUGAL FORCE IN AIR SAMPLING
SKC INC.