水泵叶轮的设计要求

直叶片一般在左视图(平面图)上画出，而扭曲叶片则应另有叶片剪裁图(也叫木模图)。目前，剪裁图比例均按1 : 1绘制，每个剪切点列成表。因为同一个叶轮有不同材料，而不同材料有不同的铸造缩比，故在剪裁图上不是只针对某一种材料。材料的铸造缩比为铸铁1.0%、铸铜1.5%、铸钢2.0%、铸不锈钢2.5%。

1)从剪裁图看叶轮的旋转方向:以背面剪裁图为主，如果叶片背面在图示右

边，则从叶轮进口看，叶轮为顺时针旋转;如果叶片背面在图示的左边，则从叶轮进口看，叶轮为逆时针旋转。剪裁图均为细实线。

2) 一般泵的叶轮流道打光要符合表2-4的要求。

3)轮毂直径d,≥(1.2~1.35) d (其中d为叶轮内孔直径)。

4)叶片厚度:如果是计算或模型换算均可，还可以根据叶轮外径D,大小，按表6-2经验数值来选取叶片厚度t。叶轮盖板厚度与叶片厚度相近即可。
5)叶轮后盖板小半径区域打印材料标记。
6)外径、开口均取消正负偏差，不只采用正偏差，只大不小，这是长期生产泵形成的习惯。如铸造时一般无法保证叶轮开口极限偏差为士0.5mm,且同一个叶轮每一开口也不会铸造得完全一样。

Design requirements of pump impeller

Straight blades are generally drawn on the left view (plan view), while twisted blades should have another blade cutting drawing (also called wood model drawing). At present, the clipping diagram scale is 1: 1, and each clipping point is listed. Because the same impeller has different materials and different materials have different casting ratios, the cutting drawing is not only for a certain material. The casting shrinkage ratio of the material is 1.0% for cast iron, 1.5% for cast copper, 2.0% for cast steel and 2.5% for cast stainless steel.

1) View the rotation direction of the impeller from the clipping diagram: the back clipping diagram is the main one, if the back of the blade is on the right side of the diagram

Side, the impeller rotates clockwise from the impeller inlet; If the back of the blade is on the left side of the figure, the impeller rotates counterclockwise when viewed from the impeller inlet. Clipping drawings are thin and solid lines.

2) Generally, the polishing of the impeller flow passage of the pump shall meet the requirements of Table 2-4.

3) Hub diameter d, ≥ (1.2~1.35) d (where d is the inner diameter of impeller).

4) Blade thickness: if it can be calculated or converted by model, the blade thickness t can also be selected according to the empirical value in Table 6-2 according to the impeller outer diameter D and size. The thickness of the impeller cover plate is close to that of the blade.

5) Material marks shall be printed in the small radius area of the impeller rear cover plate.

6) The positive and negative deviations of the outer diameter and opening are eliminated, and the positive deviation is not only used, but also large and not small. This is a habit formed in the long-term production of pumps. For example, the limit deviation of impeller opening cannot be guaranteed to be ± 0.5mm during casting, and each opening of the same impeller will not be cast completely.