Cascade Impactors, MOUDI Cascade Impactor designed to collect particles for aerosol science studies

Cascade Impactors

General Discussion | 125B and 125A Features and Applications | 100, 110, and 115 Features and Applications | Specifications

100, 110 Brochure |

125B, 125A Brochure Technical | Features | Additional Impactors (UAS, HVVI, High Flow) |

Product Brochure

MOUDI Cascade Impactor, High Concentration,
Model 125 - Request a Quote

Model 125B Rotating MOUDI cascade impactor, Model 125A Non-Rotating cascade impactor

The 125B Rotating MOUDI cascade impactor, designed for high concentration aerosols, is provided with 13 stages from 10nm to 18um, very sharp cutpoints, very low bounce response, digital On/Off timer controls and flow meters, all in one product.

Precision size classification of high concentration aerosols for
- air pollution
- pharmaceutical aerosol drug delivery
- diesel blow by and engine emission testing
- automotive airbag testing
- industrial hygiene studies
Very Sharp cut-point characteristics with little bounce from each stage
- 10-L/min sampling flow rate
- 13 impactor stages + after filter
- 18um, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.1, 32nm, 18nm, 10nm cut-points
Rotating (Model 125B) and Non-Rotating (Model 125A) products available

MOUDI Cascade Impactor 100, 110, 115 and 125
- Request a Quote

These precision, high-performance cascade impactors provide high sampling flow rate, low inter-stage wall loss, and sharp cut-point characteristics (see figure on right).

They are available as an 8-stage (Model 100) or a 10-stage (Model 110) impactor, in a rotating or a non-rotating form (see photos above). The Model 100 provides cut-point diameters of 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18 µm.

Additional cut-points at 0.1 and 0.056 µm are provided with the Model 110. The Model 115 Nano-MOUDI cascade impactor has cut-points in the nanometer range: 32, 18 and 10 nm.

Additional Impactors

Nano-MOUDI Impactor

General Discussion - Request a Quote

MOUDI 100 and 110 Cascade impactors consist of 8 or 10 impactor stages connected in series with smaller and smaller cut-point diameters. Designed for low concentration aerosols, the MOUDI 100 and 110 cut-off diameters in each stage depend on the air velocity and geometry of the stage (i.e. the distance from the nozzle to the impaction plate). The MOUDI 110 impactor has cut-point stages of 10um, 5.6um, 3.2um, 1.8um, 1um, 560nm 320nm, 180nm, 100nm, 56nm @ 30 lpm inlet flow with final filter and single stage pre-impactor of 18um. This gives the opportunity to analyze (e.g. chemical or gravimetrical) a number of small size intervals.

Some drawbacks of poorly designed conventional impactors are the risk of “bounce off” from one stage to the next (i.e. particles of wrong size at a different stage) as well as the problem of obtaining sharp cut-off diameters in the last stages (cut-off diameter less than 0.1 – 0.2 mm). Coating the impaction plates with oil or some other sticky substance, which catches the particles more effectively, can reduce the risk of bounce, but will severely complicate direct mass concentration calculations of the different stages. MOUDI Cascade Impactors are designed with superb cut-point resolution across the entire size range of 10nm to 18um with minimal bounce at each stage. The non-rotating, Nano MOUDI (see below discussion) provides sharp cut-points at 32nm, 18nm and 5.6nm at equally high resolution.

Features and Applications

Model 100 and 110 MOUDI Cut-Point Performance

Model 100 and 110 Nano-MOUDI Cut-Point Performance

Model 100, 110 and 115 MOUDI

Precision size classification of aerosols for
- air pollution
- pharmaceutical aerosol drug delivery
- diesel blow by and engine emission testing
- automotive airbag testing
- industrial hygiene studies
Sharp cut-point characteristics
Four equal geometrical intervals per decade of particle size
Models 100 and 110
- 30-L/min sampling flow rate
- 8 and 10 impactor stages + after filter
- 0.18µm and 0.056µm minimum cut-point
Model 115
- 10-L/min sampling flow rate
- 3 impactor stages + after filter
- 32, 18 and 10nm minimum cut-point

MOUDI Impactor Specifications - Request a Quote

(Subject to change without notice)

	Model 100 with rotator	Model 110 with rotator	Model 110 -1 w/o rotator	Model 125 B with rotator	Model 115 w/o rotator*
Impactor stages	8	10	10	13	3
Flow rate, L/min	30	30	30	10	10
Cut-points, µm	18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18 µm	18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.1, 0.056 µm	18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.1, 0.056 µm	18um, 10, 5.6, 3.2, 1.8, 1.0, 560nm, 320, 180, 100, 56, 32, 18, 10nm	32nm, 18nm 10 nm
(D x H)	80 x 420 mm	220 x 560 mm	220 x 560 mm	220 x 660 mm	80 x 190 mm
Weight	11 kg (24 lb)	12 kg (26lb)	2.3 kg (5.1 lb)	14 kg (29lb)	1.8 kg (4 lb)
Power	115 VAC, 60 Hz, 0.3A	115 VAC, 60 Hz, 0.3A	115 VAC, 60 Hz, 0.3A	115 VAC, 60 Hz, 0.3A
Optional	230 VAC, 50 Hz, 0.2A	230 VAC, 50 Hz, 0.2A	230 VAC, 50 Hz, 0.2A	230 VAC, 50 Hz, 0.2A

*The Model 115, 3-stage Nano-MOUDI™ is available in a non-rotating version only. The Model 115 and Model 125 requires a separate 6 CM/H vacuum pump (NAN-090) to operate.

Model 115, Nano-MOUDI Cascade Impactor

The principle of operation of the Nano-MOUDI is the same as that of the MOUDI™ impactor. It classifies particles according to aerodynamic size by inertial impaction in several multi-nozzle stages stacked in series.

The design configuration chosen for the nano-MOUDI adds three stages to the standard 10-stage MOUDI™. The cut sizes of these stages follow the four cuts per decade of particle size progression of the standard MOUDI™. Therefore, the cut sizes are 32nm, 18nm and 10nm. The absolute pressure after the last stage of the standard 10-stage MOUDI™ is about 0.60 atm. By adding three stages, the absolute pressure at the stages will become low enough so that the volumetric flow will be larger than the flow that can be pulled through a micro orifice nozzle plate. Therefore, the flow rate through the nano-MOUDI stages is decreased to 10 lpm (the flow rate in the standard MOUDI™ is 30 lpm).

The design parameters for the nano-MOUDI stages are shown in Table I, along with the same parameters for the standard MOUDI™. Note that the Reynolds Number is generally in the range of 500 to 3,000, the desired range for impactor operation1. However, the Reynolds Number of the final stages are somewhat lower than this range. Also note that the value of the pressure at the last stage is about 0.12 atm. Although this is a rather low pressure, it is substantially higher than that for a low pressure impactor which has pressures on the order of 0.03 atm for cut sizes of 0.05 µm. Corresponding pressures for the MOUDI™ at that large of a cut size is 0.60 atm.

Model 115 and 125 Nano-MOUDI Cut-Point Performance

Features and Applications

Model 125B Rotating MOUDI, Model125A Non-Rotating

Precision size classification of aerosols for
- air pollution
- pharmaceutical aerosol drug delivery
- diesel blow by and engine emission testing
- automotive airbag testing
- industrial hygiene studies
Very Sharp cut-point characteristics with little bounce from each stage
- 10-L/min sampling flow rate
- 13 impactor stages + after filter
- 18um, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.1, 32nm, 18nm, 10nm cut-points
Rotating (Model 125B) and Non-Rotating (Model 125A) products available