The inner wall of the mixing drum of the concrete mixer is usually provided with a pair of ribbon spiral blades, which are installed at an angle of 180 °, and the left-hand blades are used. When the mixing drum rotates, the two spiral blades are moved around the mixing axis to realize the feeding, mixing and unloading of concrete. The mixing drum can be divided into two sections according to its function. The tail cone outlet section is the unloading guide section. The cylindrical part and the front cone part are mainly used to stir the concrete during transportation to prevent solidification and segregation, and push out the bottom concrete during unloading.

圆锥螺旋面是指母线aa′绕圆锥中心轴线、沿筒壁螺旋线轨迹旋转，母线的运动轨迹所形成的圆锥螺旋面。母线为直线的形成直纹螺旋面，母线为曲线的形成非直纹螺旋面。在直纹螺旋面中，母线与圆锥中心轴线正交的，形成直纹正螺旋面；母线与圆锥中心轴线斜交形成直纹斜螺旋面。

Conical spiral surface refers to the conical spiral surface formed by the movement track of the generatrix AA 'rotating around the central axis of the cone and along the spiral track of the cylinder wall. Straight spiral surface is formed when the generatrix is a straight line, and non straight spiral surface is formed when the generatrix is a curve. In the ruled helicoid, the generatrix is orthogonal to the central axis of the cone to form the ruled regular helicoid; The generatrix is obliquely intersected with the central axis of the cone to form a ruled inclined spiral surface.

你以为搅拌车筒体有两条螺旋线，其实筒体内共设置了9条螺旋线，即前锥部分叶片叶根螺旋线（螺旋线1）和叶顶螺旋线（螺旋线4），圆柱部分叶片叶根螺旋线（螺旋线2）和叶顶螺旋线（螺旋线5），尾锥部分叶根螺旋线（螺旋线3）、叶中螺旋线（螺旋线6和螺旋线8）、叶顶螺旋线（螺旋线7和螺旋线9），其中螺旋线8和螺旋线9为圆柱部分与尾锥部分的过渡螺旋线。

You think there are two helixes in the mixer cylinder. In fact, there are nine helixes in the cylinder, namely, the blade root helix (helix 1) and blade top helix (helix 4) in the front cone, the blade root helix (helix 2) and blade top helix (helix 5) in the cylindrical part, the blade root helix (helix 3) in the tail cone and the helix in the blade (helix 6 and helix 8) and blade top helix (helix 7 and helix 9), wherein helix 8 and helix 9 are the transition helix of cylindrical part and tail cone part.

这些搅拌筒螺旋线的根部和顶部型式、螺旋角决定混凝土在搅拌筒内沿轴向或切向运动的强度，因而也影响着搅拌和卸料的性能，是搅拌筒设计的关键。

The root, top type and spiral angle of these spiral lines of the mixing drum determine the strength of the concrete moving along the axial or tangential direction in the mixing drum, which also affects the performance of mixing and unloading, which is the key to the design of the mixing drum.

搅拌筒螺旋线叶片设计原则

Design principle of spiral blade of mixing drum

搅拌叶片的设计一般以顺时针转动作为进料和搅拌，逆时针旋转作为出料。进料时搅拌筒的转动速度较快，为的是节省工作时间，搅拌时搅拌筒的转动速度较慢，为的是减少水分过快地蒸发，减少离析。但是在运输的过程中搅拌筒必须以恒定速度运转，为的是使混凝土不凝固变质。在简体转动的过程中混凝土被叶片连续不断地推送到搅拌筒的前部，到达前端的混凝土势必又被搅拌筒的端壁顶推反转回来，这样混凝土做前后的翻滚运动；两条叶片不停的旋转带动混凝土连续的旋转，同一位置上的混凝土通过这种运动发生连续不断的变化，从而起到搅拌作用；另外，叶片形状曲线型的变化可使混凝土在其根部与筒壁之间形成一个个小的循环运动，对搅拌混凝土也起到了一定的作用。当混凝土运输到工作地点，搅拌筒将做逆时针旋转，此时叶片的旋转方向也相反，混凝土将会被叶片引导向搅拌筒口移动，直从筒口卸出。

The design of the mixing blade generally takes clockwise rotation as the feed and mixing, and counterclockwise rotation as the discharge. During feeding, the mixing drum rotates faster to save working time. During mixing, the mixing drum rotates slower to reduce the excessive evaporation of water and reduce segregation. However, during transportation, the mixing drum must operate at a constant speed to make mixing The concrete does not solidify and deteriorate. During the rotation of the shell, the concrete is continuously pushed to the front of the mixing drum by the blades, and the concrete reaching the front end is bound to be pushed back by the end wall of the mixing drum, so that the concrete does the rolling movement before and after; the continuous rotation of the two blades drives the continuous rotation of the concrete, and the concrete at the same position occurs continuously through this movement In addition, the change of blade shape curve can form a small circular movement between its root and cylinder wall, which also plays a certain role in mixing concrete. When the concrete is transported to the working place, the mixing cylinder will rotate counterclockwise. At this time, the rotation direction of the blade is also opposite, and the concrete will be guided by the blade Move to the mixing drum mouth until it is discharged from the drum mouth.

螺旋叶片对搅拌质量的影响

Effect of spiral blade on mixing quality

以前，混凝土罐体生产企业在螺旋叶片的安装过程中，由于没有使用优化技术，没有先在板料上喷粉画线后切割卷圆，再沿着卷圆在罐体上形成的螺旋叶片母线进行安装，而是完全凭工人的生产经验进行焊接安装，导致安装完成后形成以螺旋线为母线的不合理的螺旋叶片，得到的罐体成形尺寸精度较差，进而影响到了进出料速度，使出料率较低。

In the past, in the installation process of spiral blades, concrete tank manufacturers did not use optimization technology. They did not spray powder and draw lines on the plate before cutting the winding circle, and then install the spiral blade bus formed on the tank along the winding circle. Instead, they welded and installed it completely based on the production experience of workers, resulting in unreasonable spiral with the spiral line as the bus after installation The forming dimensional accuracy of the can body obtained by rotating the blade is poor, which affects the feeding and discharging speed and makes the discharging rate low.