The Working Principle of Concrete Batch Plant

Concrete batch plant is the core equipment in the construction project, and its working principle involves many fields such as mechanical design, automation control and material science. The working principle of concrete batch plant is to use cement as the binder material, weigh fly ash, cement, aggregate (sand, stone, etc.), some powder and fine materials as well as additives, etc., through the batching machine in accordance with the proportion test, and then send it to the mixer for mixing, and then send the concrete into the concrete tanker and convey it out after achieving the required mixing effect.
 

The following is a detailed introduction to the working principle of concrete batch plant:

1. Raw material preparation stage:
- The loader will load the aggregate (sand, stone, etc.) from the stockyard into the aggregate bin for storage.
- Bulk cement delivery trucks pump cement and admixtures into powder tanks for storage respectively.
- Water and liquid admixtures are loaded into ponds and admixture tanks for storage.

2.Raw material weighing stage:
- The control system commands the material weighing system to accurately weigh the various materials.
- The material door of the aggregate bin is opened and the aggregate is put into the metering hopper to start the coarse and fine weighing of the aggregate. When the weight value measured by the sensor of the metering hopper reaches the coarse weighing value of the set value, the weighing door of one of the aggregate bins is closed and the fine weighing of the aggregate material starts. Weighing to the advance range, that is, close all the bin doors. If it is detected that it is not within the standard range of the set value, one of the silo doors will be opened automatically to carry out spot replenishment weighing.
- According to the setting of the weight value of cement and admixture, the screw machine under the corresponding powder bin will be started, and the cement and admixture will be transported to the cement measuring hopper and the admixture measuring hopper for weighing respectively, and the screw conveyor will be closed when the weighing is finished.
- According to the setting of the selection of liquid admixture, start the corresponding admixture pump, the admixture will be sent to the admixture measuring hopper weighing, weighing is complete, that is, close the admixture pump.
- The water pump starts to send water into the water metering hopper for weighing, and at the same time part of the water into the small water storage tank, and the weighing valve of the small water storage tank is open. When the weighing value reaches the rough weighing range of the set value, the water pump is turned off; until the weighing reaches the advance weighing range, the water valve is also turned off, and the water weighing is completed.

3.Raw material delivery stage:
- After weighing is completed, the operator starts the sand and stone belt motor to send the weighed ingredients to the measuring hopper.
- Cement and fly ash are conveyed to their respective metering hoppers by screw conveyors.
- Water and admixture are pumped to the respective measuring hopper by water pump and admixture pump respectively.
- After weighing the aggregate, when the system detects that the aggregate collecting hopper door is closed, the aggregate metering hopper unloading door opens, unloading the aggregate onto the flat belt already in operation, and then closing the unloading door after weighing the empty (if there is any over-weighing phenomenon, the buckled material will remain in the weighing hopper for the next disk material measurement). The flat belt conveyor will transfer the aggregate to the inclined belt conveyor, through which the aggregate will be transferred to the aggregate aggregate hopper.

4.Raw material unloading stage:
When water and admixture finish weighing, the unloading start ball valve action on the admixture metering hopper will put the admixture into the water metering hopper (fully dissolved for easy mixing).

5.Mixing stage:
According to the feeding sequence designed by the system, the aggregate aggregate hopper door, the pneumatic ball valve for discharging water metering hopper, and the pneumatic butterfly valve for discharging cement and admixture are opened respectively, and the aggregate, water, admixture, cement and admixture are fed into the mixer for mixing.
The mixer in operation will unload the raw materials, according to the mixing time set by the control system for mixing, until mixed into the required concrete (generally observed from the mixer ammeter current steady current, that is, has been mixed evenly).

6.Finished material unloading stage:
- After the mixing is completed, open the discharge door of the mixer and unload the concrete into the concrete mixer truck through the discharge hopper.
- Then it will enter the next working cycle.

The control system of the concrete batching plant adopts PLC programmable controller or touch screen control system to realize automatic and intelligent control. The control system has the following functions:
- Automation control: realize the automatic operation of the concrete batch plant through the preset program and parameters.
- Manual control: when necessary, the operator can flexibly control the concrete batch plant through manual mode.
- Alarm self-protection function: when the concrete batch plant is in trouble or abnormal situation, the control system can automatically alarm and take corresponding protection measures.
- Anti-interference function: ensure the stable operation of the concrete batch plant in the complex environment.
- Computer communication system: set the working status of the concrete batch plant, fault alarms, etc. to facilitate real-time understanding of the operation.

In summary, the working principle of concrete batch plant is a complex and delicate process, involving a number of links and equipment work together. Through precise weighing, efficient conveying, full mixing and other steps, the concrete mixing plant can produce concrete that meets the requirements, providing a solid foundation for construction projects.