Based on a sensitivity analysis of design parameters, a prototype uniflow deduster--a cyclone-type dust separator-- was developed and evaluated. The prototype has a total pressure drop of 0.4 in. water column (100 Pa) and an air flow capacity of 288 cfm(135L/s). The prototype was used to verify the uniflow particle separation theory and to evaluate the particle separation efficiency. Two types of dust were used in the evaluation, an artificial commercial dust and real swine building dust. It was confirmed that it is possible to separate particles smaller than 10mm from an airstream in air cleaning. The cut-size of the deduster ranged from 1mm to 4.5mm, depending on whether a laser particle counter or an aerodynamic particle sizer was used as the measurement device. In terms of particle count concentration measured using particle counters, the particle separation efficiency of the deduster increased with the particle size, 77% for particles at 7mm and 90% for particles at 10mm. In terms of mass concentration measured using mass samplers, the particle separation efficiency was 85%. Because most of the dust mass is attributed to the larger particles, the number separation and mass separation efficiency agreed very well. The deduster could be an effective method for cleaning dusty airspaces.Units: Dual