Mitsui Engineering and Shipbuilding Company Limited

Takeo Nojiri

Masahiro Saito

Shuji Ueki

Noboru Takemura

Yukirou Kadomoto

Izumi Onishi

Masahiro Kuwajima

Masabumi Matsumoto

Yoshikuni Kunitake

Kazuaki Kurihara

Yasuo Irie

The present invention provides a ballast water treatment system including a reaction tank in which raw water and ozone are imported and made to react each other for a predetermined period of time to kill microorganisms existing in raw water, an ozone decomposer in which water containing residual ozone discharged from the reaction tank is imported and the residual ozone is decomposed, and a circulation pump installed between the reaction tank and ozone decomposer, forming a circulation system which removes the residual ozone by means of circulating the water containing the residual ozone between the reaction tank and ozone decomposer. Accordingly, this system dispenses with a deaeration tank which would require a wide space for installation, small cost and is able to be applied to existing ships easily.

Ballast water treatment apparatus

A ballast water intake and treatment system is disclosed, the system including a membrane treatment unit arranged in or on a ship hull for the separation of microorganisms of no smaller than a given size and organized to execute filtration during the intake of sea water or fresh water outside the hull into ballast tanks by the use of an intake pump installed consecutively with the membrane treatment unit. The system checks the invasion of microorganisms, etc. of no smaller than a given size during the intake of ballast water and allows ballast water free of microorganisms, etc. of no smaller than a given size to be fed into ballast tanks.

Ballast water intake and treatment system

Planing boat

In a propeller for use in a ship of the type comprising 4 or more even number blades, at least one of two adjacent blades is inclined forwardly or rearwardly or one inclined forwardly and the other rearwardly so as to make different the rake angles of the two blades. The pitch angle of the rearwardly inclined blade is made larger than that of the forwardly inclined blade. With this construction the mutual interference between adjacent blades is efficiently utilized to prevent decrease in the efficiency even when operating conditions and the diameter of the propeller vary.

Propeller for ship

Growing community of inventors

Tokyo, Japan

Takeo Nojiri