Archimedes' screw pipe does not need to be perfectly watertight, as long as the amount of water being scooped with each turn is large compared to the amount of water leaking out of each section of the screw per turn. If water from one section leaks into the next lower one, it will be transferred upwards by the next segment of the screw. In some designs, the screw is fused to the casing and they both rotate together, instead of the screw turning within a stationary casing. The screw could be sealed to the casing with pitch resin or other adhesive, or
Dewatering screw press One modern approach even removes the screen in favor of a system of fixed and moving rings, which often eliminates solids buildup entirely. The most commonly known screw press of this design is said to have been invented by famous Greek mathematician Archimedes and is known as the screw conveyor. The screw conveyor consists of a shaft, which is surrounded by a spiral steel plate, similar in design and appearance to a corkscrew. This design is used in a multitude of screw presses. There are some machines of this and also of similar design that are not screw presses at