| 摘要 |
PCT No. PCT/CH96/00250 Sec. 371 Date Feb. 8, 1999 Sec. 102(e) Date Feb. 8, 1999 PCT Filed Jul. 8, 1996 PCT Pub. No. WO97/21925 PCT Pub. Date Jun. 19, 1997In prior art designs, single-flight cast double worms with angles of contact >720 DEG with large balance hollows at both ends and worm lengths of whole multiples of the pitch operate in the medium rotation speed ranges ( DIFFERENCE 3000 min DIFFERENCE 1) without imbalance. The desired use of special uncastable materials and the manufacturing complexity and the necessary dimensional stability even for extreme profile geometries pose additional problems in balancing which are solved by the present invention. Here, it is possible, by varying the angle of contact of the worm and any balance hollows and/or by altering the contour of the worms in the medium engagement region, to reduce the size of the balance hollows, sometimes to "zero", and with the possible use of additional masses. Besides the advantage of simple raw component manufacture, worms balanced in this way also permit the use of special materials and extreme worm geometries for fitting in pumps used in the chemical, medical and food sectors.
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