In the concrete mixing plant, the mixing of concrete is divided into six stages: raw material preparation stage, raw material weighing stage, raw material transportation stage, raw material unloading stage, mixing stage, and finished material unloading stage。
1、 Raw material preparation stage
The raw material preparation stage includes the following processes: the loader loads the aggregate from the storage yard into the aggregate bin for storage; Bulk cement transport vehicles transport cement and admixtures separately into powder tanks for storage; Store water and liquid additives in water tanks and additive tanks.
2、 Raw material measurement stage
Start the mixing plant (air compressor, inclined belt, flat belt, and main machine start running), set the required concrete raw material formula for production, and operate the equipment.
The material door of the aggregate bin is opened, and the aggregate is put into the measuring hopper to start the coarse and fine weighing of the aggregate. When the weight value measured by the measuring bucket sensor reaches the coarse weight value of the set value, close one of the weighing doors in the aggregate bin and start fine weighing of the aggregate. Close all warehouse doors when weighing to within the advance range. If it is detected that it is not within the set value standard range, a warehouse door will be automatically opened for jog feeding and weighing.
According to the weight values of cement and admixture selected according to the settings, the screw conveyor under the corresponding powder silo is started, and the cement and admixture are respectively transported to the cement metering hopper and admixture metering hopper for weighing. After weighing, the screw conveyor is closed.
Select liquid admixtures according to the settings, start the corresponding admixtures pump, and send the admixtures into the admixtures measuring hopper for weighing. After weighing, turn off the admixtures pump.
The water pump starts to send water into the water metering bucket for weighing, while a portion of the water enters the small water storage tank and the weighing valve of the small water storage tank opens; 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 range, the water valve is also closed and the water weighing is completed.
The above weighing processes are the raw material measurement stages, where the weighing of all scales on the first plate is carried out simultaneously. Starting from the second plate, the aggregate is cross weighed to save time.
3、 Raw material transportation stage
After the aggregate weighing is completed, when the system detects that the aggregate hopper door is closed, the discharge door of the aggregate measuring hopper opens, and the aggregate is unloaded onto the already running flat belt. After weighing it empty, the discharge door is closed (if there is an over weighing phenomenon, the material will be retained in the weighing hopper for further measurement). The flat belt conveyor transfers the aggregate to the inclined belt conveyor, and the aggregate is transferred to the aggregate hopper through the inclined belt conveyor.
4、 Raw material unloading stage
After the water and admixture are weighed, the ball valve action is activated when the admixture is discharged from the metering hopper, and the admixture is put into the water metering hopper (fully dissolved and easy to mix).
According to the feeding sequence designed by the system, the aggregate hopper door, water metering hopper discharge pneumatic ball valve, and cement and admixture discharge pneumatic butterfly valve are opened respectively, and the aggregates, water, additives, cement and admixture are written into the mixer for mixing. After the unloading is completed, it enters the next weighing cycle.
5、 Mixing stage
The mixer in operation will unload the raw materials and mix them according to the mixing time set by the control system until the required concrete is mixed (usually after a stable current is observed on the ammeter of the mixer, it is evenly mixed).
6、 Finished product unloading stage
After mixing is completed, the driving mechanism of the mixer opens the discharge door and unloads the finished concrete into the mixing truck through the discharge hopper. The unloading time and unloading status (half open or full open) can be adjusted according to the actual situation.
After the mixer is unloaded and the discharge door is fully closed, the next mixing cycle begins.
