The design philosophy of the sampler is based upon drawing air through a 0.152mm slit at 1 cubic foot/minute and impinging the particles contained therein upon an agar surface 2–3mm below the slit. The agar is contained in a commercially available 150mm X 15mm disposable culture plate which is rotated by a synchronous drive motor. The rate of rotation can be varied by the interchangeable drive motors. After sampling, the plate is incubated and the colonies counted. This count reflects the number of airborne particles carrying viable organisms. No dilution or plating steps are required. Results are expressed as viable particles per unit of air and a time concentration relationship may be determined.
On operation, the pressure of the compressed gas (maximum 125 psi, minimum 5 psi) is reduced by a constant pressure reducing regulator pass through a 0.152mm slit, and the resident particles contained therein impinged upon an agar surface 2-3mm below the slit. The agar is contained in the same commercially available culture plate as described for Model 220.
After sampling, the drive motor and gas supply shut off automatically. The plates that are removed, incubated and the colonies contained by standard techniques. The results may be expressed as viable particles or colony-forming units per cubic foot of gas at atmospheric pressure.
Same as for Model 220 with the exception of the following:
For sampling specific areas such as "point of fill" or laminar flow cabinets. Equipped with 8' of Tygon tubing and screw on remote probe cap.
For Model 220 only.
Available for both models, the HEPA filter can be added as an extra precautionary measure to prevent carbon particles produced from the vacuum pump from escaping into the environment being monitored.
For interchangeable petri dish drive motors are available with one revolution per 60-min, 30-min, 15-min, and 5-min. This adjusts the sensitivity to the expected concentration of airborne organisms.