Electric Concrete Mixer Machine: Twin Shaft Batch Mixer
Jun 12, 2023
An electric concrete mixer machine is a machine driven by a motor and rotates in a tank to mix cement, sand aggregate and water into concrete mixture. It is mainly composed of a mixing drum, a feeding and unloading mechanism, a water supply system, engine, transmission mechanism, frame and supporting device. It is the core component of the concrete mixing plant.
The twin shaft concrete mixer is driven by dual motors, and the two mixing main shafts are driven by V-belts and planetary reducers. The rotating blades on the main shafts push the materials in the mixing drum and form a cross flow, so as to achieve the purpose of rapid production of homogeneous concrete.
1. Working speed of twin-shaft mixer
The mixing speed of the dual shaft concrete mixer has a key influence on the quality of concrete and the efficiency of production. If the speed is low, the mixing time will be increased, thereby reducing productivity; if the speed is high, a large centrifugal force will be formed, and the concrete is prone to segregation, which will damage the homogeneity of the concrete. When the speed exceeds the critical speed, the degree of damage to its homogeneity is more serious.
At the same time, the increase in rotational speed will inevitably lead to an increase in stirring power. Therefore, determining a reasonable rotational speed has great practical significance for giving full play to the function of the concrete mixer.
2. Design of volume utilization factor
The feed volume is 1.6 times of the discharge volume, and the mixer design should have 10% overload capacity. Different countries also have different standards for the value of capacity utilization. The volume utilization rate of German mixers is 0.52-0.534, the volume utilization rate of Italian mixers is 0.45-0.52, and the volume utilization rate of Japanese Nikko mixers is 0.35-0.38. At present, the volume utilization ratio of mixers in China is mostly between 0.5 and 0.52, which can better ensure the utilization of power.
3. Measured energy consumption and power data
Take JS3000 twin shaft batch mixer for example. The length of the mixing drum is 2.06m, the radius R of the mixing drum is 0.64m, and the size of the mixing blade is L=0.29m and H=0.2m.
C30 concrete was used as the test material for the test. It was measured that when the 3m3 concrete mixer was fully loaded and mixed, the maximum power of a single motor was 48.5kW; when C40 concrete was used as the test material, the maximum power of a single motor was 50.5kW. It can be seen that the calculated value is very close to the measured value, with an error of about 6%.
It can be seen that the use of two 55kW motors for the 3m3 concrete mixer meets the requirements. The power margin of the motor is reasonable, the working energy consumption of the mixer is 0.22-0.25kW/h, and the energy consumption at no-load is less than 10% of the rated power.