The concrete mixing station is mainly composed of 5 major systems, such as the main mixing machine, material weighing system, material conveying system, material storage system and control system, and other auxiliary facilities. What is its main classification and working principle?
1. Classification of concrete mixing plant
1. According to its different structure, it can be divided into mobile mixing station and fixed mixing plant. The construction site is suitable for mobile mixing stations.
2. According to different operation forms, it can be divided into two types: periodic and continuous. The periodic feeding and discharging system circulates according to a certain period. Continuous feeding and discharging are carried out continuously. At present, the cycle type is generally used.
3. According to different process layout, it can be divided into two types: single-order and double-order.
Single step lifts sand, stone, cement and other materials to the roof silo at a time. Various materials are weighed, batched, and agitated according to the process flow. The mixing building is divided into the silo layer, weighing layer, mixing layer and bottom layer from top to bottom. The single-stage process flow is reasonable and the productivity is high, but the factory is required to be high, so the investment is large, and this form is generally used in mixing plants.
The storage bins and mixing equipment of the double-stage materials are generally on the same level. The aggregate is sent to the storage bin after being lifted, and accumulated and weighed separately under the storage bin, and then sent to the mixer with a lifting hopper or belt conveyor for mixing. Since the material needs to be upgraded twice, the productivity is low, but it can reduce the height of the full set of equipment, facilitate disassembly and assembly, and reduce investment. Generally, this form is usually used in mixing plants.
Second, the working principle of the concrete mixing plant
The concrete mixing station is divided into four parts: sand and stone feed, powder (cement, fly ash, expansion agent, etc.) feed, water and admixture feed, transmission mixing and storage. Its working process is shown in Figure 1. After the mixer control system is powered on, it enters the operation interface of the human-machine dialogue, and the system performs initialization processing, including formula number, concrete grade, slump, production volume, etc. According to the weighing, each silo and weighing hopper Detection, output empty or full signal, prompt the operator to determine whether to start the stirring control program. Start the sand and stone belt motor to feed into the measuring hopper; open the fly ash and cement tank butterfly valve, start the screw machine motor to transport fly ash , Cement to the measuring hopper; open the control valves of the water tank and the admixture tank to allow water and additives to flow into the measuring hopper. After the measurement meets the set requirements, open the measuring hopper door, and the ingredients enter the mixer that has been started to mix and mix to the set Time to open the mixer door, and the concrete enters the mixing truck that has received the material.
1. Each cylinder, control valve and motor operate according to the requirements of the concrete mixing process. The control of each cylinder, control valve and motor must be accurate, stable and reliable.
2. The control system has two working modes, automatic and manual, and the relationship between them is independent and restricts each other.
3. The system has good anti-interference ability and perfect alarm self-protection function.
4. Through communication with the computer, it can display the system working status and fault alarm.
