After practice and analysis, we believe that the causes of tank sticking can be divided into two categories: unreasonable design and improper use
(1) The discharge residual rate and blade design are unreasonable. From the internal structure of the mixing drum, the mixing drum of the automatic feeding mixing truck relies on the spiral movement of the two spiral blades driven by the rotating drum, which makes the concrete obtain the compound movement of both "tangential" and "axial", so that the mixing drum has the function of mixing and discharging, Such as the curve parameters of the spiral blade, the geometry and size of the mixing drum have an important influence on the discharge residual rate of the mixer. The excessive discharge residual rate means that there will be more surplus materials in the automatic feeding mixer after the discharge, so it is more likely to stick in the mixing tank due to accumulation over time. At present, most manufacturers use equiangular logarithmic spiral blade, and there is still a lot of room for improvement in discharge residual rate.
(2) The working environment temperature of automatic feeding mixer is too high. In summer, around noon in the daytime in southern China, the ambient temperature often exceeds 30 ℃. In this case, due to the rapid slump loss of concrete and the higher temperature around the tank, the concrete is easier to stick to the tank.
(3) The transportation distance is too long. With the process of urbanization and the requirements of urban planning, more and more mixing plants are required to move to the suburbs and counties, and the distance from the urban area is getting farther and farther. Due to the particularity of concrete, any premixed concrete without adding retarder will enter the initial setting state in one hour, It not only affects the engineering quality of concrete, but also because of the loss of fluidity of concrete, it is easy to coagulate on the mixing drum and blades, resulting in sticking to the tank. In serious cases, even the whole vehicle of concrete sticks to the tank and causes damage to the hydraulic equipment. Therefore, the automatic feeding mixer truck has its time controlled conveying radius for transporting premixed concrete, which should be generally controlled within 1h.
(4) Improper use and maintenance. The driver of the automatic feeding mixer fails to clean the residual concrete in the mixing tank and on the blades after the unloading of the mixer, and does not rotate the mixing tank when the mixer returns to the station. The residual concrete solidifies on the mixing drum and blades after drying, and then it will gather more and more, forming the phenomenon of sticking to the tank.