| 摘要 |
PURPOSE:To prepare a spherical powder with a specified fineness by preparing a powder with a long and slender shape by cutting thermoplastic synthetic resin pellets and preparing a spherical fine powder with good flow properties by cutting the long and slender powder with air voltex flow having a temp. of about softening temp of the resin. CONSTITUTION:Pellets 37 of a thermoplastic synthetic resin are fed into a disc-type grinder 1 and thinly ground from the surface by means of blades 5 and 6 of a fixed and rotating discs 3 and 4 to become long and slender powder, which is fed into a turbo-type fine grinder 17 through a duct 29. The fed powder is finely cut with an air voltex flow rotating with a high speed in channels of the back parts of a number of projected ridges 19 on the inner face of an outer box 18 and an air voltex flow rotating with a high speed on the back of blades 25 rotating around the central line B-B and at the same time, heat is generated by the vigorous air voltex flow and the powder becomes soft as temp. is elevated in the air flow and becomes spherical body by the action of the surface tension. Then, the powder is fed into a cyclone separator 31, wherein it is separated into air and powder and fine powder 38 having passed through the meshes of a vibrational screen 35 is taken out as a product. |
