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泵葉輪和泵體的測繪

泵損壞后，當購買不到這臺泵的備件時，只能實地測繪來解決。泵的測繪主要是泵葉輪和泵體的測繪，因為泵的葉輪和泵體決定了泵的性能，同時泵的葉輪和泵體測繪繪圖比較困難。它不但形狀是一個曲面，圖紙表示方法也很特殊，所以這里主要介紹泵葉輪和泵體的流道水力模型的測繪、繪型方法，而其他零件的測繪繪圖同一般機械零件的測繪制圖，不作詳細介紹。

泵葉輪和泵體的測繪方法很多，下面介紹的方法是我們從實踐中總結出來，自行研究的一種方法， 實踐證明是一種比較正確方便的方法，并且可以不破壞葉輪而得到。
一、泵葉輪葉片測繪
1.葉片繪型的一些基本知識

(1)葉片工作面和背面:離心泵的葉片，一般都是后彎葉片， 如圖7-1(b) 所示，朝著旋轉方向的將能量傳遞給液體的葉片表面稱工作面，相對應的反面稱為葉片背面。

(2)軸面: 經過葉輪軸心線的平面稱為抽面，如圖7-1(b)中的0-0、0-1、0-2、3-0 ....等平面。
    (3)軸面投影圖:將葉輪的前、后蓋板和葉片的進、出口邊， 用旋轉投影的方法投影到同一軸面上， 例圖7-1 (a)稱軸面投影圖。

(4)軸面截線:某一個軸面與葉片工作面、背面的兩條交線稱軸面截線。軸面與葉輪工作面的交線稱工作面軸面截線，如圖7-1 (a) 陰影部分的實線為軸面2 -0的工作面軸面截線。陰影部分的虛線為軸面2-0的背面軸面截線。

對離心泵葉片，軸面截線可分為三種形式:一種是圓柱形葉片，如圖7-2 (a) 所示，軸面截線成一條平行于軸線的直線;第二種是斜葉片，如圖7-2 (b)所示，軸面截線是一條斜直線;第三種是扭曲葉片，如圖7-2 (c)所示，軸面截線是一條曲線。 對圓柱形葉片，只要測出截線上任意點就可以確定其軸面截線， 對于斜葉片，需測出截線上兩點(一般為前、后蓋板上的兩點)就可以確定其軸面極線。面對于扭曲葉片，就必需測出椒線上數點，才能確定軸面截線。
(5)葉片剪裁圖(葉片術模圖): 葉片模型制作時，有的人習慣用葉片剪裁圖(木模圖)來制作。葉片剪裁圖是一組垂直于葉輪軸心線的平面(或稱割面)于葉片工作面和背面的交線(為一條空間曲線) 在平面圖上的投影。 用軸面截線可以轉給成葉片剪裁圖(葉片模型截線)，同樣也可以將葉片剪裁圖轉繪成軸面截線。

用軸面截線繪制葉片剪裁圖的方法如下，見圖7-3。

①在葉輪葉片的軸面截線圖上，作垂直于葉輪軸心線的直線1 -1、2-2、3-3--這些直線實質就是一組垂直于葉輪軸心線的平面，通常稱為割面或等高面，它們與葉片的交線就是葉片模型截線。直線1-1、 2 -..可以是等題離的，也可以不等距離的，距離大小視葉片扭曲程度而定，扭曲較大時，距離取得小些。

②作平面投影圖，以0點為圓心，作葉輪的外圓，并作中心角為Av的軸面投影線0、1、.... ...40 010~15C. 

③將軸面投影圖沿后蓋板流線與各葉片工作面截線交點投影到平面圖上，又將沿前蓋板流線與各葉片工作面截線交點投影到平面圖上即為葉片工作面的輪廓曲線。作圖方法是:以0點為圓心，以蓋板流線與軸面截線的交點到軸心線的垂直距離為半徑劃弧，與各軸面線的交點用光滑的曲線連接即成葉片工作面的輪廓線。同樣方法，可作出葉片背面的輪廓線，布置在另一邊。這里要注意的是葉片工作面輪廓線與葉片背面輪廓線左右布置位置與葉片旋轉方向的關系。因為從葉輪入口看葉片時，只能看到葉片背面，因此平面視圖中葉片背面輪廓線的進口邊為葉輪的旋轉方向。例圖7-3中，從葉輪進口方向看為順時針旋轉。

④作模型截線:例圖7-3，1 -1割面的模型截線，1 -1割面與軸面0、I、II的軸面截線相交于c、b、a點，它們到軸心的距離分別為R。、R:、R。，在圖7-3 (b)平面投影圖上，以0點為圓心，以R。、R、R。為半徑分別劃弧交于0、1、I軸面于c、b、a點，光滑連接a、b、c,這就是割面1-1葉片背面的模型截線。同樣方法，可以作出2-2、3-3、4-4割面葉片背面的模型截線。

同樣方法，又可作出葉片工作面的模型截線畫于另一邊。 這就是葉片截線圖或稱葉片剪裁圖。

葉輪測繪就是要測繪出軸面截線圖或葉片截線圖。渣漿泵

Mapping of pump impeller and pump body

After the pump is damaged, when the spare parts of the pump cannot be purchased, it can only be solved by field mapping. The mapping of pump is mainly the mapping of pump impeller and pump body, because the impeller and pump body determine the performance of pump, and the mapping of pump impeller and pump body is difficult. It is not only a curved surface, but also a special drawing representation method, so this paper mainly introduces the mapping and drawing method of the hydraulic model of the impeller and the flow passage of the pump body, while the mapping of other parts is the same as that of general mechanical parts, without detailed introduction.

There are many surveying and mapping methods for pump impeller and pump body. The method introduced below is a method that we have summed up from practice and researched by ourselves. It has been proved to be a more correct and convenient method in practice, and it can be obtained without damaging the impeller.

I. mapping of pump impeller blades

1. Some basic knowledge of blade drawing

(1) working face and back face of blade: the blades of centrifugal pump are generally backward curved blades. As shown in Figure 7-1 (b), the surface of the blade that transfers energy to the liquid in the direction of rotation is called the working face, and the corresponding back face is called the back face of the blade.

(2) shaft surface: the plane passing through the impeller shaft axis is called the extraction surface, as shown in 0-0, 0-1, 0-2, 3-0... And other planes in Figure 7-1 (b).

(3) axial projection: the front and rear cover plates of impeller and the inlet and outlet sides of blades are projected on the same axial plane by the method of rotary projection. For example, Figure 7-1 (a) is called axial projection.

(4) axial section line: the two intersecting lines between a certain axial surface and the working surface and the back of the blade are called the axial section line. The intersection line between the shaft surface and the impeller working surface is called the cutting line of the working surface. As shown in Figure 7-1 (a), the solid line of the shaded part is the cutting line of the working surface of the shaft surface 2-0. The dashed line in the shadow part is the back axis section of axis 2-0.

For centrifugal pump blades, the axial section line can be divided into three forms: one is cylindrical blade, as shown in Figure 7-2 (a), the axial section line is a straight line parallel to the axis; the second is inclined blade, as shown in Figure 7-2 (b), the axial section line is an oblique straight line; the third is twisted blade, as shown in Figure 7-2 (c), the axial section line is a curve. For cylindrical blades, as long as any point on the section line is measured, the axial section line can be determined. For inclined blades, two points on the section line (generally two points on the front and rear cover plates) can be measured to determine the axial polar line. In the face of the twisted blade, it is necessary to measure the number of points on the pepper line to determine the axial section.

(5) blade cutting drawing (blade technical model drawing): some people are used to making blade cutting drawing (wood model drawing) when making blade model. The blade cutting drawing is the projection of a set of plane (or cut plane) perpendicular to the axis line of the impeller on the plane of the intersection line (a space curve) between the working face and the back face of the blade. It can be transferred to the blade cutting drawing (blade model cutting line) by using the axial cutting line, and it can also be transferred to the axial cutting line.

The method of drawing blade cutting diagram with axial section is as follows, as shown in Figure 7-3.

① on the sectional drawing of the axial surface of the impeller blade, make lines 1-1, 2-2, 3-3 perpendicular to the axial line of the impeller -- these lines are essentially a group of planes perpendicular to the axial line of the impeller, usually called the cutting surface or the contour surface, and the intersection line between them and the blade is the sectional line of the blade model. The straight lines 1-1, 2 -.. can be equidistant or equidistant. The distance depends on the degree of blade twist. When the twist is large, the distance is smaller.

② make the plane projection drawing, take point 0 as the center, make the outer circle of the impeller, and make the axial projection line 0, 1,...... 40 010 ~ 15C with the center angle of AV

(3) the profile curve of the blade working surface is projected on the plan along the intersection of the streamline of the rear cover plate and the section line of each blade working surface, and on the plan along the intersection of the streamline of the front cover plate and the section line of each blade working surface. The drawing method is as follows: take point 0 as the center, take the intersection point of the streamline of the cover plate and the intercept line of the shaft surface to the vertical distance of the axis line as the radius to draw an arc, and connect the intersection point with each axis line with a smooth curve to form the contour line of the blade working surface. In the same way, the contour line on the back of the blade can be made and arranged on the other side. What should be noted here is the relationship between the left and right position of blade working face contour and blade back contour and blade rotation direction. Because only the back of the blade can be seen when looking at the blade from the impeller inlet, the inlet edge of the blade back contour in the plan view is the rotation direction of the impeller. For example, in Figure 7-3, clockwise rotation is seen from the impeller inlet direction.

④ make model section line: for example, figure 7-3 shows the model section line of cutting plane 1-1. The section lines of cutting plane 1-1 and axis planes 0, I and II intersect at points c, B and a. the distances from them to the axis are respectively R. R:, R. , on the plane projection of figure 7-3 (b), take point 0 as the center, and take R. R, R. Make arc intersection on axis 0, 1, I at points c, B, a for radius respectively, and connect a, B, C smoothly, which is the model section line on the back of blade cutting surface 1-1. In the same way, the model lines on the back of blades with 2-2, 3-3 and 4-4 cutting surfaces can be made.

In the same way, the model section line of blade working face can be drawn on the other side. This is the blade screenshot or blade clipping.

Impeller mapping is to map out the shaft section or blade section. Slurry pump