Parallel Particle Impactors – New Personal Samplers for ... · Parallel Particle Impactors – New Personal Samplers for Accurate ... Dorr-Oliver Cyclone, Q S ... *US Patent pending

Parallel Particle Impactors –New Personal Samplers for Accurate

Assessment of Worker Exposure to Respirable or Thoracic Dust

Saulius Trakumas, Peter M. Hall, and Donald L. SmithSKC Inc., Eighty Four, Pennsylvania

www.skcinc.com

Sampler should approximate particle penetration through human respiratory tract when purpose of monitoring workers exposure to airborne particulates is health-related.

ACGIH, CEN, and ISO have defined sampling conventions for size-selective

sampling of airborne health-related particles:

Inhalable (particles that enter nose/mouth)Thoracic (fraction of particles that penetrates down to the larynx) Respirable (fraction of particles that penetrates down to the alveolar region of the lungs)

Size-selective Sampling Conventions for Health-related Airborne Particulates

Aerodynamic Particle Diameter, da, µm1 10 100

Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100

Inhalable

ThoracicRespirable

Size-selective Particle Samplers

Cyclone

Performance of Six Respirable Cyclones

Aluminum

Aerodynamic Particle Diameter, da, µm0 2 4 6 8 10

Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100

Respirable Convention

Dorr-Oliver Cyclone, QS=1.7 L/min

Test Aerosol:DOP Glass Spheres Coal Mine Dust

Dorr-Oliver


Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100


GS-1 Cyclone, QS=2.0 L/min


GS-1 GS-3


Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100


SIMPED Cyclone, QS=2.2 L/min


BGI-4CP


Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100


BGI-4CP Cyclone, QS=2.2 L/min


SIMPED


Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100


GS-3 Cyclone, QS=2.75 L/min



Sam

plin

g Ef

ficie

ncy,

E, %

0

25

50

75

100


Aluminum Cyclone, QS=2.5 L/min



CycloneFoam


CycloneFoam Horizontal elutriator


CycloneFoam Horizontal elutriator Conventional impactor


Pene

trat

ion,

P, %

0

25

50

75

100


Single Impactor: d50=4.0 µm

Two impactors: d50=5.6, and 2.9 µm

Four impactors: d50=6.6, 4.6, 3.5, and 2.2 µm

Six impactors: d50=7.1, 5.4, 4.4, 3.7, 3.0, and 1.8 µm

Simulation of Respirable Curve Using Impactors

V. Marple’s design of multiple-nozzle, single-stage impactor*

021 VP ρ=∆

0

5050

9CV

WStDpρ

µ=

µρ 0

50WVRe =W1 W2

* Virgil A. Marple. 1978. Simulation of Respirable Penetration Characteristics by Inertial Impaction. J. Aerosol Sci., Vol.9, pp.125-134.

80.873.5530.332.2

12.45.8No. of nozzlesdin, mmD50,µm

160.632.512.55.0

No. of nozzlesdin, mmD50,µm

230.483.051.04.2

1090.222.1

12.36.4No. of nozzlesdin, mmD50,µm

Qs=2.0 Lpm

Parallel Particle Impactor (PPI)

021 VP ρ=∆ iOutiIni PPP ∆+∆=∆

2222

22

21

21 2

121.....

21

21

21

21

NOutNInOutInOutIn VVVVVV ρρρρρρ +==+=+

⎟⎟⎠

⎞⎜⎜⎝

⎛+==⎟⎟

⎠

⎞⎜⎜⎝

⎛+=⎟⎟

⎠

⎞⎜⎜⎝

⎛+ 22

222

22

222

121

21

11.....1111

NOutNInN

OutInOutIn SSQ

SSQ

SSQ

W1in W2in

*US Patent pending

W1out W2out

Parallel Particle Impactor Prototype

1.332.064.6

2.591.302.21.401.733.5

1.302.596.6dout, mmdin, mmD50,µm

Respirable PPI (Qs=2.0 Lpm)

2.184.0011.9

5.102.124.82.253.258.9

2.125.1017.5dout, mmdin, mmD50,µm

Thoracic PPI (Qs=2.0 Lpm)

Experimental Setup

%100)()()( ×=

dCdCdE

Up

Down

Test aerosol used:

DOPPSTGlass SpheresCoal Mine Dust

Clean Air(50 Lpm)

VirtualImpactor

ChargeNeutralizer

TurbulenceGenerators

HoneycombFlow Straightener

Clear PlexiglassCylinder

(D=12 , H=48 )” ”

AccessPort

Foam

SamplingLines

BallValve

TestDevice

To Filter

Makeup Flow

AerosolGenerator

AerodynamicParticle Sizer (APS 3320)

APS was calibrated periodically using PSL particles of known size

To minimize erroneous counts and coincidence effect, small test particles were removed before entering test chamber using a virtual impactor and test particle concentration inside the chamber was kept below 100 cm-3.

Experimental Setup

Aerodynamic Particle Diameter, da, µm0 2 4 6 8 10 12

Pene

trat

ion,

P, %

0

25

50

75

100

QS=0.5 L/min PST test particles

Impactor 50% cut-off, d50, µm No Design Measured

1 6.6 6.42 4.6 4.73 3.5 3.6 4 2.2 2.3

Performance of Individual Impactors of Respirable PPI Prototype

Overall Performance of Respirable PPI Prototype


Pene

trat

ion,

P, %

0

25

50

75

100

QS=2.0 L/min PST test particles

Curve constructed using experimentaldata obtained for each individual impactorPerformance of whole sampler


Performance of sampler exposed to coal minedust for 6 hours (~ 4.5 mg/m3)


Pene

trat

ion,

P, %

0

25

50

75

100

Test Particles:

PST (ρp=1.79 g/cc)

DOP (ρp=0.99 g/cc)

Glass Spheres (ρp=2.5 g/cc)


Performance of Respirable PPI Prototype when Tested Using Different Test Particles


Pene

trat

ion,

P, %

0

25

50

75

100

HD Cyclone, QS=2.2 L/minRespirable Convention

PPI, QS=2.0 L/min

Comparison of Performance of RespirablePPI Prototype and HD Cyclone

Bias Maps of Respirable PPI Prototype and HD Cyclone

1.5

2.0

2.5

3.0

3.5

1 3 5 7 9 11 13 15 17 19 21 23 25Geo

met

ric S

tand

ard

Dev

iatio

n, G

SD

Mass Median Diameter, MMAD, µm

1.5

2.0

2.5

3.0

3.5 <-10% -10%< <-5% -5%< <5% 5%< <10% >10%

Respirable PPI prototype

HD Cyclone

Inlet

Exhaust

ImpactionPlate

Parallel Particle Impactor Final Design

Performance of Respirable and Thoracic PPIs

Aerodynamic Particle Diameter, da, µm

Pene

trat

ion,

P, %

0

25

50

75

100

Respirable PPI

Thoracic PPI

Thoracic Convention


0.5 1 5 10 50

Conclusion

A novel design incorporating several inertial impactors arranged in parallel was applied to fabricate respirable and thoracic PPIs.

PPIs were found to follow accurately appropriate conventions. PPI samplers performed equally well for liquid and solid test particles and penetration characteristics remained unchanged after prolonged exposure to coal mine dust.

Conclusion

The suggested PPI design can be applied to model a sampler with characteristics simulating the shape of any monotonically changing predetermined curve at a selected flow rate.

Documents

Parallel Particle Impactors – New Personal Samplers for ... · Parallel Particle Impactors – New Personal Samplers for Accurate ... Dorr-Oliver Cyclone, Q S ... *US Patent pending