Gear pump for plastics, particularly elastomers, has symmetric helical teeth separated by a gap filled by a multi-part blocker

摘要

The gear wheels(12,14) have symmetric areas of helical teeth separated by a gap into which a blocker(28) is inserted. A main part(30) of the multi-part blocker(28) is on the outlet side of the pump(10) and divides an outlet chamber(22) of the latter. Secondary parts(32,34) of the blocker completely fill a semi-circular part of the conveying gap(20). A blocker may also be located in the inlet chamber(18). The helical teeth(42,44) have a conveying action towards the gap(24). Radial depth of the blocker is similar to that of the gear teeth. Gap breadth is 0.1-2 times, preferably 0.5 times, the tooth(26) height. Secondary blocker parts can be inserted and removed according to the desired ratio between efficiency and temperature reduction. An inlet side bevel on the first secondary blocker part(32) guides material to the helical teeth. Both sets of teeth on the first gear wheel mesh with teeth on an opposing gear wheel and both wheels are in a housing(16). The outlet chamber and particularly the inlet chamber, when the latter also includes a blocker, is covered by a removable outlet wall(40) which permits removal of blocker parts for pump cleaning.