Concrete mixing blade working principle and spiral curve form

 

What is the working principle of concrete mixing blade? What are the forms of spiral curves of concrete mixing blades? Zhengzhou Changli Machinery Manufacturing Co., Ltd. introduces the professional knowledge of concrete mixing blade for you today.

 

The working principle of concrete mixing blade

During the working process of concrete mixer truck, the two continuous spiral blades inside the mixing cylinder rotate at the same time, pushing the concrete along the axial and tangential direction of the mixing cylinder, making it produce compound movement, so that the mixing cylinder has the working performance of mixing and discharging. Therefore, the design of the mixing cylinder spiral blade directly affects the working performance of the mixing cylinder.

 

According to the traffic rules of our country on the right side of the vehicle, in the design of the mixing cylinder steering, positive rotation for the rear of the car, clockwise rotation, the mixing cylinder for the feeding or mixing state; and reverse rotation for counterclockwise rotation, the mixing cylinder for the unloading state, so the two spiral blades in the mixing cylinder should be set up for the interlocking 180º left spiral blades.

 

In the working process of the mixing cylinder, the different turning of the two continuous spiral blades makes it produce the function of mixing and discharging, because the shape and working nature of each part of the mixing cylinder are different, so the design should be considered separately.

 

According to the actual working situation, it is generally divided into two sections, the rear part of the cone of the mixing cylinder is the discharge guidance section, that is, when the mixing cylinder in reverse rotation, the spiral blades guide to push the concrete discharge; and the front cone and the cylinder against the front cone part for the mixing section, in the mixing cylinder forward rotation, the spiral blades on the concrete mainly play the function of mixing.

 

The form of the spiral curve of the spiral blade of the mixing cylinder   

The design of the spiral blade is the key part of the concrete mixing cylinder design. The spiral curve of the spiral blade has various forms, and the main parameters are determined by the spiral lift angle ɑ. The size of the helix angle ɑ directly affects the movement of the concrete in the mixing cylinder. The specific relationship is analyzed as follows: 

 

(1) when the ɑ angle is very small, the spiral blade and the axis of the mixing cylinder close to the vertical degree, the mixing cylinder in the rotation around its axis, the concrete along the axial displacement is small, basically only do along the wall of the tangential slide movement, at this time the blade not only mixing role is tiny, and also does not have the function of unloading. 

 

(2) When the ɑ angle gradually increases, the mixing cylinder in the rotation around the shaft, the concrete along the axial displacement increases, at this time the blade mixing and unloading function is enhanced, when the composite movement of concrete reaches a certain degree, the working performance of the mixing cylinder can reach the expected design. But on the other hand, with the increase of ɑ angle, the frictional resistance of concrete sliding along the blades also increases, to a certain angle, concrete siltation on the blades, so that its overall mixing is blocked, seriously affecting the mixing efficiency and discharge performance, sometimes also block the mixing cylinder discharge port. 

 

(3) When the ɑ angle tends to 90º, the mixing cylinder spiral blade and its axis is basically parallel, at this time the mixing cylinder in the rotation around its axis, the concrete is almost subject to only the mixing effect, axial displacement is tiny, so the mixing cylinder discharge function is completely lost.     

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