| 摘要 |
PCT No. PCT/NO90/00190 Sec. 371 Date Jun. 4, 1992 Sec. 102(e) Date Jun. 4, 1992 PCT Filed Dec. 17, 1990 PCT Pub. No. WO91/08891 PCT Pub. Date Jun. 27, 1991.This invention is directed to a lubricating arrangement for a plastic extruder (1) for production of cylindrical plastic tubes with a smooth inner surface. The plastic extruder (1) includes a mandrel which consists of a die core (6) which is a cylindrical coaxial extension of an extruder screw (2). Die core (6) rotates together with said screw, and a stationary external die member (7). The lubricating arrangement is located in the external die portion for lubricating its forming surface. The lubricating arrangement has a plurality of radially directed plugs (11, 11', 17, 17'), each plug engaged in a bore (10) in the external die member. The inner end of the plug lies in the die surface. Lubricating ducts (13) are provided to the bore which are connected with a source of a lubricant, which supplies a lubricant under pressure.
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