双流道污水泵叶轮的绘型方法

Drawing method for double channel impeller

研究了双流道污水泵叶轮常用的图纸表达方法,发现平面图上的断面投影结果与轴面图中确定的断面形状尺寸不一致的问题.断面形状为沿对称轴对折的椭圆,此对称轴始终垂直于轴截面,其方向与平面图上的流道中线无关.传统设计中认为以垂直于平面图上的流道中线确定的截面尺寸并不符合实际的投影关系.这是设计中经常出现的双流道叶轮平面图、断面面积图与叶轮木模图三者不一致的主要原因.提出在双流道污水泵叶轮设计时,平面绘型作为初步设计,然后在三维造型中确定其余参数,再由三维造型来生成平面绘型,以保证设计与木模一致.设计结果表明,这种设计步骤是合理的.

The drawing method for the double channel impeller is studied. It is found that there is an inconformity between the dimensions of plane-view and pinacoid-view of fluid cross-section. The shape of cross-section is an ellipse folded in half through one symmetry axis, and the axis keeps perpendicular with pinacoid-view. Thus the direction of the cross-section is unrelated with center channel curve in planeview. Traditionally, it is assumed that the cross-section is perpendicular to the center-channel curve. This is not the fact. It is considered that the major cause is resulted from the disagreement among plane view, dimension of cross-section and actual wood former of double channel impeller. A more reasonable design process is proposed.