the leading features of 2w series twin screw pump 1.deliver various medium smoothly without and disturbing and pulsation. there are medium to be pumped throughout in the working elements as sealing liquid which guaranteed by the construction of pump casing. all of the pumps possess high self-priming ability and can deliver the liquid mixed with gas or air. 2.the high suction performance namely very low npshr was guaranteed by the special design of pump. 3.adopting the external bearing which lubricated individually, so can deliver various non-lubricative medium. 4.adopting synchronous gear, there is on metallic contact between rotating parts, there is no dangerous even dry running in a short time. 5.various construction completely such as horizontal, vertical and casing with liner, and so on. the pump can handle various clean liquid without solid grain, low or high viscosity medium, even can deliver some corrosive medium with a correct material selection. 6.suction of the pump is at the flank and discharge is on the top, the pump has small cubage, so it is especially used to the place of small space, such as ship.