Self-priming pumps have low efficiency
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The company manufactured a standard single-stage horizontal external mixing self-priming pump with a flow rate of 200, a head of 55, and an operating speed corresponding to stage 4; it is based on the ZA150-400 model. Priming works fine, but its efficiency is 13% lower than that of normal pumps. Is this normal? Please ask experienced experts to help with the analysis
Was the hydraulic basis of the pump body not increased during the modification? The position of the separator tongue also needs to be modified
The changes you mentioned are those aimed at improving the self-priming performance of the pump during the self-priming process; however, the tests were conducted under normal operating conditions after self-priming had taken place, so the efficiency should not be much lower than that of the original pump
I think a reduction of 5-8 percentage points is sufficient; if the reduction is greater, it’s likely that the gas-liquid separation chamber expands suddenly at the outlet of the pump’s discharge volute, resulting in excessive losses and a significant drop in efficiency