Abstract
A centrifugal pump with a nutating impeller is called tea-spoon type pump. Aiming at improvement of efficiency, we invented a new-type TS pump. A spherical-cone impeller nutates, as if a piston moves in an endless cylinder, in the annular passage between the inside of casing and the outside of inlet portion. Initially we made a simplified two-dimensional model of that pump and investigated the relasions of pump performance to the following items: shapes and dimensions of casing, inlet- and outlet-portions, an impeller and the annular passage. The casing with swelling ahead of the outlet proved to be better than the circular casing. Referring to the above-mentioned results, we made and investigated a new-type TSpump of three-dimensional structures. Preliminarly experiments showed that the obtained pressure and efficiency were about 60% of the two-dimensional model, this was maybe caused by decrease in the effective piston area of the impeller. Hereafter, we intend to improve its characteristics by changing shape and clearance of the annular passage.
