| 摘要 |
A method and a unit for the extrusion of foam material comprises a horizontal vacuum chamber 10 with a front plate 11 and an extrusion nozzle 16, which are fitted at one end of the chamber, so that the extrusion nozzle is situated in the chamber when the front plate is closed. A liquid barrier, preferably of water, is applied at the opposite end of the chamber, and the extruded product is led out from the chamber to the outside through this liquid barrier, which comprises a liquid reservoir 30 with a higher level 32 in the chamber and a lower level 31 outside this. The higher liquid level is formed between a damming plate 20 and a sealing plate 12, the latter constituting the opposite end of the chamber. A window 34, the size of which is adjustable, and through which the extruded product can pass, is formed in this sealing plate 12, the product being fed by a conveyor 43 obliquely down into the liquid and, submerged therein, being fed out through the sealing plate into an upwardly curved section having a large radius. The liquid level in the chamber is adjusted in that liquid is circulated by members 50, 51 from the higher level in the chamber to the lower level outside this, so that the circulated quantity of liquid is inversely proportional to the absolute pressure in the vacuum chamber. The circulated liquid may possibly pass through a cooler 61, in order to regulate the liquid temperature. The adjustment of the size of the window or the outlet opening in the sealing plate may be used, especially when starting up, to control the flow of liquid from that part of the liquid reservoir having a lower level and situated outside the chamber to that part of the liquid reservoir having a higher level and situated inside the chamber. <IMAGE>
|
