To realize sufficient pump performance while increasing the degree of freedom of the water content rate of a medium by forming a rotor of a synthetic resin in which the dimension changing rate of the rotor becomes a specific % or below against the medium whose water content rate is a specific weight % or below.
In a Westco type pump, a rotor 26 is rotatively stored in a housing 25 formed of a light metal, and this rotor 26 is formed of a synthetic resin whose dimension changing rate becomes 0.15% or below against a medium whose water content rate is 10wt.% or below. Then, both surfaces of the rotor 26 are approached and opposed to a housing main body 30 and a cover 31, and connected to a rotary shaft 28 through a key 29, and many blade grooves 26a having equal intervals in a circumferential direction, are arranged in both surfaces of the peripheral part of the rotor 26. Hereby, sufficient pump performance can be obtained while enlarging the degree of freedom of the water content rate of the medium.
KAMEDA TOSHIHIRO
OKADA TETSUHIRO
YAMAZAKI EIJI
