| 摘要 |
<p>A method and apparatus are disclosed for the manufacture of foamed polystyrene particles of moderately great density, such as 3 to 25 lbs. per cubic foot (50 to 400 milligrams per cubic centimeter). Beads are fed by a constantdisplacement auger to an expander vessel having the form of, in its lowest part, a cylinder with a vertical axis, and thereabove, of a frustrum of an inverted cone having a base angle of about 83 to 70.degree.. Steam is supplied to the vessel in an appropriate, controlled manner. The vessel also contains stator bars, to break lumps and retard the rotation of the material in the vessel, and rotating bars, to provide the necessary agitation. Desirably, the equipment includes a discharge chute of adjustable location, to facilitate adjustment of the residence time and consequently of the density of the expanded beads being produced. With apparatus according to the invention, it is possible to obtain beads substantially uniformly expanded to a desired density within the range indicated above. Such higher-density expanded polystyrene particles find use in various applications, such as shoe soles, or as a substitute for wood.</p> |
