US 9,808,978 B2
Screw elements with reduced energy input during the build-up of pressure
Michael Bierdel, Leverkusen (DE); Thomas König, Leverkusen (DE); and Ulrich Liesenfelder, Bergisch Gladbach (DE)
Assigned to COVESTRO DEUTSCHLAND AG, Leverkusen (DE)
Appl. No. 12/999,409
Filed by Michael Bierdel, Leverkusen (DE); Thomas König, Leverkusen (DE); and Ulrich Liesenfelder, Bergisch Gladbach (DE)
PCT Filed Jun. 9, 2009, PCT No. PCT/EP2009/004122
§ 371(c)(1), (2), (4) Date Apr. 8, 2011,
PCT Pub. No. WO2009/152974, PCT Pub. Date Dec. 23, 2009.
Claims priority of application No. 10 2008 029 306 (DE), filed on Jun. 20, 2008.
Prior Publication US 2011/0180949 A1, Jul. 28, 2011
Int. Cl. B29C 47/08 (2006.01); B29B 7/48 (2006.01); B29C 47/38 (2006.01); B29C 47/40 (2006.01); B29C 47/64 (2006.01); B29C 47/62 (2006.01); B29C 47/60 (2006.01); B29C 47/00 (2006.01)
CPC B29C 47/0861 (2013.01) [B29B 7/481 (2013.01); B29C 47/0881 (2013.01); B29C 47/38 (2013.01); B29C 47/402 (2013.01); B29C 47/6056 (2013.01); B29C 47/6075 (2013.01); B29C 47/625 (2013.01); B29C 47/627 (2013.01); B29C 47/64 (2013.01); B29C 47/0009 (2013.01); Y02P 70/263 (2015.11)] 21 Claims
OG exemplary drawing
 
1. Screw elements for multiscrew extruders with pairs of co-rotating screws, wherein the screws are fully wiping in pairs, and wherein each screw has one of:
a generating screw profile and a generated screw profile consisting of arcs with non-infinite radiuses, each of the generating and generated screw profiles being axisymmetric referring to one axis which passes through the point of rotation of the respective screw profile,
wherein each of the generating screw profile and the generated screw profile comprises one sealing region, one or more transition regions, one channel region, one or more tip regions, one or more flank regions, and one or more grooved regions, and each screw profile consists of a sequence of the one sealing region, one of the transition regions, the one channel region, another of the transition regions, and
further wherein
the sealing region consists of a sequence of tip region, flank region, tip region,
the channel region consists of a sequence of root region, flank region, root region, and
each transition region is one of the flank regions.