particle used was Kanto Loam (JIS, Z8901, No. 11). The mass median
diameter was 1.8 μm and true density was 2900 kg/m3. The total flow
rate, including secondary flow rate of 100 l/min was changed from 500
to 700 l/min and powder flow rate was set about 2.0 g/min.
Fig. 2 shows the dimensions of the test cyclone. In this study,
various types of apex cones were used at the inlet part of the dust box.
The cone angles examined were from 40° to 80°. In general, the cone
angle of 60° is used in the gas-cyclone, but the optimum cone angle of
the apex cone has not been clearly investigated. For each experiment,
the spacing between the bottom of the cylindrical part and the bottom
of the apex cone was set to be 31.2 mm. Under this condition, the top
position of the apex cone and the bottom of the cylindrical wall were
set at nearly the same height.