Screw pump different applications and handling fluids with varying characteristics. Each ‘screw pump' operates on the same basic principle of a screw turning to isolate a volume of fluid and convey it. However, the mechanical design of each is different. The primary difference is the number of screws: one, two, three or more. The screw pump was described by Archimedes on the occasion of his visit to Egypt. This suggests that the apparatus was unknown to the Greeks before Hellenistic times. A cuneiform inscription of Assyrian king Sennacherib (704–681 BC) has been interpreted by Stephanie Dalley to describe casting water screws in
Archimedes (CAD) Archimedes (CAD) Archimedes – "The Open CAD" – (also called Arquimedes) is a computer-aided design (CAD) program being developed with direct input from architects and architecture firms. With this design philosophy, the developers hope to create software better suited for architecture than the currently widely used AutoCAD, and other available CAD software. The program is free software released under the Eclipse Public License. Archimedes uses its own XML-based open format, which resembles SVG. It does not yet include support for other , but DXF support is planned. Archimedes is written in Java, and the latest version runs on Windows, Mac