This article describes the maximum allowable cut of the outer impeller of the pump, from the specific rpm of the pump, the amount of cutting allowable, and the resulting reduction in efficiency. At the same time should pay attention to the following two points: 1, vortex pump and axial flow pump impeller is not allowed to cut 2, impeller outer circle cutting is generally not allowed to exceed the value specified in this table, in order to avoid excessive pump efficiency decline. Specific rotation ns ≤ 60 60 to 120 120 to 200 200 to 300 300 to 350 350 or more Allowable cutting amount (D1-D2) / D1 20% 15% 11% 9% 7% 0 Decrease in efficiency Decrease by 10% % 4% decrease per car by 1% -
