Product Details
The Model 120FC has been designed for use in conjunction with the MOUDI II cascade impactor Model 120, but it can also be configured for other air samplers with similar flow pumping requirements. Consult with TSI on these alternate configurations.
The magnitude of the volumetric flow rate at the impactor inlet is controlled in real time by adjusting the speed of the pump with a closed-loop feedback control system. The mass flow rate exiting the impactor is HEPA-filtered and measured with an internal, temperature-compensated mass flow sensor. Using ambient pressure and temperature measurements, the inlet volumetric flow rate is calculated and compared with the flow rate setpoint (i.e. 30 L/min default value). The controller then adjusts the pump frequency needed to maintain a constant inlet volumetric flow rate equal to the setpoint. This adjustment is done in a continuously during the entire sampling interval, and therefore the volumetric flow rate is always maintained at a constant value (e.g. < 1% precision) regardless of changes in the sampling conditions (i.e. P, T or sampler ΔP).
The Model 120FC is designed for indoor and outdoor operation. The pump and associated electronics are mounted inside a sealed metal enclosure that has been designed for outdoor use.