Filter media test rig for determination of MPPS range

The largely automated setup of the test sequence and the clearly defined individual components, and the individually adjustable sequence programs of the filter test software FTControl combine to deliver the high reliability of our measurement results.

The MFP filter test rig is a modular filter testing system for flat filter media and small mini-filters.
Pressure loss curves, fraction separation efficiency, or burden can be determined within a very short period – both reliably and cost-effectively.

1. Variable aerosol generation with the UGF 2000 for KCl / NaCl or DEHS. We integrated silica gel drying length. The volume flow for aerosol generation is individually regulated via mass flow controllers.

2. Aerosol neutralization: Soft x-ray Charger XRC 049 or Corona discharge (optional).

3. Mobile pneumatic filter holder for fast removal and loading of the test rig.

4. Movable dilution cascades:
The dilution cascades enable defined dilution of the applied test aerosol by the factors 10, 100, 1,000 and 10,000. As they are movable, the test rig can be changed over quickly from salt aerosols to DEHS aerosols. Lengthy or complex cleaning of the systems is not required.

Alternatively, the dilution system can be selected for only one test aerosol.

5. U-SMPS for nanoparticle measurement
The Palas^® filter test software FTControl controls the U-SMPS and evaluates the data.

Adjustment of the aerosol distribution to the MPPS range

Through a suitable selection of the solution concentration, the generated particle size distribution is matched to the relevant MPPS range in the MFP Nano plus.

Fig. 1: Adjustment of the particle sizes for the required MPPS range with DEHS

Fig. 2: Comparison of fraction separation efficiencies in the MPPS range at 140 nm

Automation:
The MFP Nano plus has integrated mass flow controllers to control the volume flow; these can be automatically monitored and controlled via the FTControl filter test software.
Sensor data such as the filter's volume flow and differential pressure are recorded automatically during the filter test. The raw gas measurement is performed without the filter medium with a dilution factor matched to the separation efficiency (10, 100, 1,000 or 10,000). The clean gas measurement is then performed without dilution and with the filter medium inserted. The change in dilution factor is performed automatically.

Verification of the dilution factor:
The dilution systems integrated into the MFP Nano plus work like the tested VKL series with the ejector principle. The advantages of this dilution cascade are the apparent transfer behavior, low level of contamination, and simple cleaning.

Fig. 3: Verification of the dilution factor via raw/clean gas comparison with a factor of 10 and NaCl particles

Literature

• Łukasz Werner a,*, Bartosz Nowak a, Anna Jackiewicz-Zag´orska a, Małgorzata Gołofit-Szymczak b, Rafał L. G´orny: Functionalized zinc oxide nanorods – polypropylene nonwoven composite with high biological and photocatalytic activity. https://www.sciencedirect.com/science/article/pii/S2213343723018183