Abstract: A co-current cyclone separator comprised of (a) a cyclone housing having a cylindrical section of diameter Dcycl and having a cover; (b) a tangential inlet fitting for introducing a cyclone feed mixture, the cyclone feed mixture containing a fluid and suspended mechanical particles; (c) an axial exhaust nozzle having an inlet diameter Dout, for discharging said fluid; and (d) a dust-collecting bin for collecting the suspended mechanical particles, wherein the suspended mechanical particles are largely removed from the cyclone feed mixture and collected in the dust-collecting bin, thereby reducing the concentration of the suspended mechanical particles in the fluid discharged through the axial exhaust nozzle, and wherein the ratio of Dcycl to Dout is in the range of 3:1 to 20:1.