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水泵葉輪的設計要求

直葉片一般在左視圖(平面圖)上畫出，而扭曲葉片則應另有葉片剪裁圖(也叫木模圖)。目前，剪裁圖比例均按1 : 1繪制，每個剪切點列成表。因為同一個葉輪有不同材料，而不同材料有不同的鑄造縮比，故在剪裁圖上不是只針對某一種材料。材料的鑄造縮比為鑄鐵1.0%、鑄銅1.5%、鑄鋼2.0%、鑄不銹鋼2.5%。

1)從剪裁圖看葉輪的旋轉方向:以背面剪裁圖為主，如果葉片背面在圖示右

邊，則從葉輪進口看，葉輪為順時針旋轉;如果葉片背面在圖示的左邊，則從葉輪進口看，葉輪為逆時針旋轉。剪裁圖均為細實線。

2) 一般泵的葉輪流道打光要符合表2-4的要求。

3)輪轂直徑d,≥(1.2~1.35) d (其中d為葉輪內孔直徑)。

4)葉片厚度:如果是計算或模型換算均可，還可以根據葉輪外徑D,大小，按表6-2經驗數值來選取葉片厚度t。葉輪蓋板厚度與葉片厚度相近即可。
5)葉輪后蓋板小半徑區域打印材料標記。
6)外徑、開口均取消正負偏差，不只采用正偏差，只大不小，這是長期生產泵形成的習慣。如鑄造時一般無法保證葉輪開口極限偏差為士0.5mm,且同一個葉輪每一開口也不會鑄造得完全一樣。

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.