Centrifugal fluid pump assembly

A centrifugal fluid pump assembly which includes a housing having a fluid inlet and a fluid outlet, an impeller rotatable within said housing for feeding fluid by centrifugal force upon rotation thereof, and a motor for rotating said impeller, comprising:

• a motor current flow rate-related data storage section for storing, for a plurality of different predetermined viscosities, predetermined viscosity-related flow rate data formed from a plurality of motor current flow rate relation data at a plurality of different impeller rotational speeds at predetermined fluid viscosity;
• a fluid measurement data inputting section;
• an impeller rotational speed measurement function or an impeller rotational speed calculation function;
• a motor current measurement function;
• and
• a flow rate calculating section for calculation, using a fluid viscosity value inputted to said fluid measurement data inputting section or calculated from a fluid measurement data inputted to said fluid measurement data inputting section, an impeller rotational speed value obtained by said impeller rotational speed measurement function or impeller rotational speed calculation function, a measured motor current obtained by said motor current measurement function and the data stored in said motor current flow rate-related data storage section, a fluid flow rate at the fluid viscosity value, the measured motor current and the impeller rotational speed value.