1. Principle and structural characteristics of screw conveyor
The working principle of screw conveyor is similar to that of a nut rotating on a screw which does not move axially. In the process of axially rotating movement, the rotating spiral blade in the material trough will push the material to move. The material is fed into the trough body from the feed port, and then sent to the other end along the screw, and discharged from the discharge port. The structure of screw conveyor mainly includes driving device motor, reducer, material chute, screw shaft, screw blade attached to screw shaft, support at both ends, inlet and outlet, discharge outlet and inspection port. The screw conveyor is simple in structure, easy to seal, and uses frequency converter to control the operation. The powder drop is relatively small, which can improve the accuracy of feeding control and measurement accuracy. It has a large adjustable range, good wear resistance and low operating cost. Therefore, it is widely used in concrete mixing station.

I. What lubricants are used in reducers?
1. Horizontal cycloidal reducer is lubricated by oil pool under normal conditions. The oil surface height can be maintained in the middle of the oil window. Cyclic lubrication can be used when the working conditions are bad and the ambient temperature is high.
2. Cycloidal pinwheel reducer is usually lubricated with 40 or 50 mechanical oil at room temperature. In order to improve the performance of the reducer and prolong the service life of the cycloidal pinwheel reducer, 70 or 90 extreme pressure gear oil is recommended. Lubrication oil should also be reconsidered when working at high and low temperatures.

1. Daily Maintenance and Fault Diagnosis of Concrete Mixing Station

1.1 Daily Maintenance and Fault Diagnosis of Mixing Main Building

The most important component of concrete mixing station is mixing main building. Therefore, in order to maintain the mixing station, it is necessary to maintain the main mixing building, that is, the main mixing machine, powder weighing, admixture weighing, water weighing, sand and gravel buffer hopper and inclined motor.

The planetary gear reducer matched with the Spearman mixer reducer was found to be damaged when it was used for more than nine months, which resulted in the failure of its normal use. The reducer model is YNF1110, transmission ratio is 500 and assembly type is V11. The YP250M-4 motor matched before the damage of the reducer works continuously in one direction for 25 K W, 1450 r/min, nominal transmission ratio i=500, 24 hours, ambient temperature is room temperature, and the working medium of the mixer is liquid or semi-liquid. In this paper, the causes of gear shaft damage of reducer are analyzed.

1 Physical and chemical examination