Slit-to-Agar
Biological Air Samplers
Particle Distribution Guide
The particle distribution guide helps determine the time of occurrence and duration of a contamination event. |
APPLICATIONS
Slit-To-Agar (STA) air samplers have become a lab standard for detecting airborne microbial contamination. New Brunswick Scientific has improved the original designs with two new models that provide a dynamic sampling range, more precise control and easier validation. STA 203 and STA 204 Models have been successfully used in a variety of environments including pharmaceutical facilities, hospitals, food and cosmetics labs, and in the detection of terrorist-dispersed anthrax.
PRINCIPLE OF OPERATION
A known volume of air is drawn by vacuum through a slit orifice that accelerates the sampled air and its contaminants. Located below the slit and in the path of airflow is an exposed agar plate that rotates on a turntable at a selected rate of speed. The contaminants, because of their higher mass, become impacted on the agar surface, while the rest of the air mass flows around the plate and exits the air sampler. After incubation of the agar plate, colonies can be counted and identified. A particle distribution grid can also be used to help determine when a contamination event occurred.
FEATURES
New Brunswick STA models utilize microprocessor controls, variable speed turntable and a thermal mass flow controller. This allows the user to select an extraordinarily broad sampling volume range. For clean room environments, the STA 203 can sample a volume up to 5 cubic meters (5000 liters). In environments with more viable particles, the STA 203 and STA 204 can sample as little as 0.03 cubic meters (30 liters).
Model STA 203
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Model STA 204
With Built-In Vacuum Pump
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Flow rates and sampling time are easily entered using a membrane keypad. Total sampling volume is automatically computed and continuously displayed on a large, easy to read LED indicator. Sample volume for each run can also be output to a recorder for validation purposes.
STA 203 is used with a customer-supplied vacuum pump capable of at least 2.2 cu.ft. air/minute at 15" Hg. STA 204 is supplied with a vacuum pump.
UNIQUE FEATURES & BENEFITS
- Sample volume is accurately calculated by measuring and controlling air flow using a thermal mass flow controller. (Competitive units merely assume a constant flow rate or use a volume flow meter, which are both adversely affected by temperature and pressure).
- Flow rate validation enabled via output signal for data recording.
- Audible & visual alarms signal power interrupt, variation in flow rate, or end of sample run, with output signals for remote alarming.
- Capable of identifying when a contamination event occurs.
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