Perforated Lid

The Perforated lid for MAS-100 NT^® (300 x 0.6 mm) is made from anodized aluminum and can be used with the portable MAS-100 NT^® and the MAS-100 VF^® microbial air samplers. The sieve of the perforated lid is at the core of the viable air sampler. Each hole must have an identical diameter and length to accelerate the aspirated air correctly. The 3mm thickness of the perforated sieve guarantee a well-defined impaction jet. The impaction speed defines the physical sampling efficiency. The cut-off value D50 (the particle size at which 50% of the particles impact in the agar due to inertia and 50% are exhausted with the airstream) must be identical between holes and between lids. That is why intense quality control of the sieves is performed. The sieve pattern with 300 holes of a diameter of 0.6 mm provides an impaction speed of approximately 20 m/s at a flow rate of 100 l/min. This impaction speed allows a high physical efficiency, meaning a sampling efficiency of more the 50% of small particles at a size of less than 1.1 μm (D50, calculated, below 0.8 μm in validation studies) while maintaining the viability of microorganisms during impaction on the agar surface (biological efficiency).
The validation of physical and biological efficiency has been independently performed for each individual MAS Air sampler model. The perforated lid can be autoclaved and disinfected with all disinfectants compatible to anodized aluminum in order to avoid false positive results in high grade cleanrooms. The sampling efficiency for an instrument must remain identical, irrespective of the lid used. Our perforated lids allow the exchange of several lids with identical sieve pattern on the MAS air sampler without the need of re-calibration.

The perforated lid with 300 x 0.6 mm hole sieve is used for microbial monitoring of ambient air with portable MAS-100^® microbial air samplers in controlled environments, such as ISO 5 cleanrooms. Microbial air sampling devices are extensively used in Pharmaceutical and Personal care industries as well as in Food, Beverage and Environmental applications.

MAS-100 is a registered trademark of MBV AG

MAS-100 NT is a registered trademark of MBV AG

MAS-100 VF is a registered trademark of MBV AG