The working principle of concrete mixer truck | liquid tank truck manufacturer
With the rapid development of concrete production and construction technology, some countries have gradually adopted the method of centralized mixing and commercial supply of concrete. The concrete is provided by a special concrete mixing station and then transported to various construction sites by concrete mixing trucks. Now briefly introduce the structural principle and maintenance of the concrete mixer truck.
1 Composition and working principle of concrete mixer truck
The concrete mixer truck is composed of a car chassis and a special device for concrete mixing and transportation. The chassis of concrete mixer trucks produced in my country mostly use the second-class general chassis provided by the vehicle manufacturers. Its dedicated mechanism mainly includes power take-off, front and rear supports of the mixing drum, reducer, hydraulic system, mixing drum, operating mechanism, cleaning system, etc. Its working principle: Take out the power of the car chassis through the power take-off device, and drive the variable pump of the hydraulic system, convert the mechanical energy into hydraulic energy and transmit it to the fixed motor, and then the motor drives the reducer. The reducer drives the mixing device to carry out the concrete Stir.
1.1 Power take-off device
The domestic concrete mixer truck adopts the power take-off method of the main vehicle engine. The function of the power take-off device is to take out the engine power by manipulating the power take-off switch, and drive the mixing drum through the hydraulic system. The agitating drum rotates positively during the feeding and transportation process to facilitate the feeding and mixing of the concrete. Reverse rotation, cut off the power connection with the engine after the end of the work.
1.2 Hydraulic system
The engine power taken out by the power take-off is converted into hydraulic energy (displacement and pressure), and then output by the motor as mechanical energy (speed and torque) to provide power for the rotation of the mixing drum.
After decelerating the output speed of the motor in the hydraulic system, it is transmitted to the mixing drum.
1.4 Operating mechanism
A. Control the direction of rotation of the mixing drum so that it rotates forward during feeding and transportation, and rotates backward during discharge.
B. Control the speed of the mixing drum
1.5 Stirring device
It is mainly composed of a mixing drum and its auxiliary supporting parts. The mixing drum is a concrete loading container. It is made of high-quality wear-resistant thin steel plate. In order to automatically load and unload concrete, the inner wall of the mixing drum is welded with special-shaped spiral blades. When rotating, the concrete moves along the spiral direction of the blades, and is mixed and stirred during the continuous lifting and turning process. During the feeding and transportation process, the mixing drum rotates forward, and the concrete moves inward along the blades. When discharging, the mixing drum reverses and the concrete is discharged along the blades. The rotation of the mixing drum is ensured by a hydraulic drive device. The concrete mixer truck with a loading capacity of 3-6 cubic meters generally adopts the hydraulic pump driven by the automobile engine through the power output shaft, and then the hydraulic motor driven by the high-pressure oil to drive the mixing drum. The loading capacity of 9-12 cubic meters is driven by the on-board auxiliary diesel engine. The hydraulic pump drives the hydraulic motor. The blade is the main part of the mixing device, damage or severe abrasion will cause uneven concrete mixing. In addition, if the angle of the blade is unreasonably designed, it will also cause segregation of the concrete.
1.6 Cleaning system
The main function of the cleaning system is to clean the mixing drum, and sometimes it is also used to mix dry materials during transportation. The cleaning system also cools the hydraulic system.
2 Maintenance and repair of concrete mixer truck
As a transportation vehicle, the concrete mixer truck must comply with the Ministry of Transport Order No. 13 of 1990 in terms of maintenance and repair, and implement the maintenance and repair system of "regular inspection, mandatory maintenance, and repair based on conditions". Under this major premise, combined with the actual situation of the concrete mixer truck, maintenance and repair should be done. In terms of daily maintenance, the concrete mixer truck should not only maintain the car engine, chassis and other parts according to the routine, but also must do the following maintenance work.
2.1 Cleaning the concrete storage tank (mixing drum) and the inlet and outlet
Since concrete will solidify into a hard block in a short time and is corrosive to steel and paint, it is necessary for daily maintenance to wash the concrete adhering to the concrete storage tank and the inlet and outlet after each use of the concrete storage tank. Serious work. These include:
A. Rinse the feed port with water before each filling to keep the feed port moist during filling;
B. Fill the washing water tank that comes with the car with water while loading;
C. Rinse the feed port after loading, and clean the remaining concrete near the feed port;
D. After unloading at the construction site, flush the discharge chute, and then add 30-40 L of cleaning water to the concrete storage tank; keep the concrete storage tank rotating slowly when the vehicle returns;
E. Remember to drain the sewage in the concrete storage tank before loading the next time;
F. Clean the concrete storage tank and around the material inlet and outlet thoroughly at the end of the day to ensure that there is no cement and concrete agglomeration.
As long as these tasks are not carried out seriously once, they will cause great troubles in future work.
2.2 Maintenance drive device
The function of the driving device is to drive the rotation of the concrete storage tank. It is composed of a power take-off, a cardan shaft, a hydraulic pump, a hydraulic motor, a control valve, a hydraulic oil tank and a cooling device. If this part stops working due to a malfunction, the concrete storage tank will not be able to rotate, which will cause the concrete in the vehicle to be scrapped, and even the whole tank of concrete will condense in the tank, causing the concrete mixer truck to be scrapped. Therefore, whether the driving device is reliable is an issue that must be paid attention to in use. In order to ensure the integrity and reliability of the drive device, the following maintenance work should be done:
A. The universal rotating part is the part where failures frequently occur. Grease should be added on time, and the wear condition should be checked frequently and repaired and replaced in time. The team should have a spare cardan shaft assembly to ensure that it can resume work within tens of minutes in the event of a failure.
B. Ensure that the hydraulic oil is clean. The working environment of the concrete mixer truck is harsh, and the dirty cement sand must be prevented from entering the hydraulic system. The hydraulic oil should be replaced regularly according to the requirements of the user manual. Once the hydraulic oil is found to be mixed with water or sand during the inspection, it is necessary to stop the machine immediately to clean the hydraulic system and replace the hydraulic oil.
C. Ensure that the hydraulic oil cooling device is effective. It is necessary to clean the hydraulic oil radiator regularly to prevent the radiator from being blocked by cement, check whether the electric fan of the radiator is operating normally, and prevent the hydraulic oil temperature from exceeding the standard. As long as the hydraulic oil is clean, there are not many failures in the hydraulic part; however, the service life is different if the manufacturer is different.
2.3 Pay attention to the maintenance of tires
In addition, our unit produces: oil tank trucks, sprinkler trucks, fecal suction trucks, sewage suction trucks, dump trucks, vans, garbage trucks, trainer trucks, truck cranes, aerial work trucks, powdered material bulk cement trucks, chemical Liquid transport trucks, cement mixer trucks, etc.