Abstract
For the centrifugal pump applying to sewage water containing foreign bodies, higher pump efficiency and non-clogging characteristic are required. In order to improve its performance, authors have developed new type impeller. In these pumps, the ratio of blade width to the impeller diameter (b_2/D_2) varies in each impeller, since the passage diameter (called minimum particle diameter) inside the impeller depends on the discharge pipe diameter. This yields different specific speed in each pump. Therefore, it is very important in the design of these pumps to understand the effect of specific speed on the pump performance. In this investigation, experiments were conducted on the several impellers with the specific speed in range of 248-343 (m, m^3/min, min^<-1>). As a result, it was found that pump efficiency deterioration within the range of specific speed is less than 5%.
