Screw conveyor segment with a slowly rotating feed screw used for precision metering by conveying very small amounts of loose material between screw threads. The same amount of loose material being discharged from the end of the conveyor with each turn of the screw. They are used for conveying all kinds of granular material such as foodstuffs, cement, coal and sugar. They are used as material compressors, water and effluent pumps, mixers & measures and even in large-scale concrete mixers. These are used for precision metering of very small amounts, which is used for conveying very small amounts with a high degree of constancy without the periodicity caused by the nature of the feed screw. It is provided with a rotatably mounted tube surrounding the discharge end of the fixed feed tube, which is driven at a rotational speed proportional to the rotational speed of screw.