In the process of producing concrete, self compacting concrete mixer needs accurate measurement of raw materials such as aggregate, powder, liquid admixture and water. For the mixer truck which has no fixed outdoor work place and needs to be mixed and poured on site, it is necessary to keep the stability and stability of the equipment and frame in the measurement process to ensure the high-quality raw material measurement process. It can be used in all aspects of mixer structure.

骨料的输送和计量，采用了石子和砂叠加计量输送的皮带秤装置。骨料在卸料进入皮带秤的过程中，因空间的落差存在，使得卸料门接收信号关闭后，有多余骨料进入到皮带秤中。通过软件、电气控制，使其具备能够自动补偿骨料的落差量，准确达到计量的目标值。皮带秤使用裙边皮带进行骨料输送，皮带侧边的裙边结构能防止砂、石子向侧边漏料，保障计量准确。砂计量皮带采用变频控制，能根据计量的需要调节输送的速度，进一步提高计量精度。

Aggregate transport and measurement, the use of gravel and sand overlay metering conveyor belt scale device. In the process of discharging the aggregate into the belt scale, due to the existence of space gap, after the receiving signal of the discharge door is closed, there is surplus aggregate into the belt scale. Through software and electrical control, it can automatically compensate the drop of aggregate and accurately achieve the target value of measurement. Belt weigher uses skirt belt for aggregate conveying. The skirt structure on the side of belt can prevent sand and stone from leaking to the side and ensure accurate measurement. The sand metering belt adopts frequency conversion control, which can adjust the conveying speed according to the needs of metering, so as to further improve the metering accuracy.

粉料的使用量小于骨料的使用量，为达到精确的计量，需要采用更严格的措施。搅拌车在进行粉料的配料工作时，粉料通过带有变频功能的螺旋输送机进行输送后，进入匹配的粉料秤中计量。通过变频控制对螺旋输送速度进行调节，初始计量时快速送料，节省时间；计量接近目标值时慢速送料，把控精度。以此在兼顾效率的情况下，实现了粉料的粗、精计量效果。与皮带秤类似，螺旋输送机与粉秤之间也存在高度落差，为提升计量精度，粉料计量系统采用了“一增一减”控制算法。

The usage of powder is less than that of aggregate. In order to achieve accurate measurement, more strict measures need to be taken. When the mixing truck is mixing the powder, the powder is transported by the screw conveyor with frequency conversion function and then measured in the matching powder scale. The screw conveying speed is adjusted by frequency conversion control, so that the material can be delivered quickly in the initial metering, saving time; When the measurement is close to the target value, the feeding speed is slow to control the accuracy. In this way, the coarse and fine metering effect of powder is realized under the condition of efficiency. Similar to the belt scale, there is a height drop between the screw conveyor and the powder scale. In order to improve the metering accuracy, the powder metering system adopts the "one increase and one decrease" control algorithm.

在框架、箱体振动不可避免的情况下，为了保证水和液体外加剂准确计量，采用传统的单吊点式、以拉式传感器计量的方式不是选择。采用拉式传感器作为计量元件的液体秤，其原理是通过感应计量重量产生的重力应变，转换为电信号得到重量值，在混凝土搅拌站中应用广泛。然而由于其感应灵敏的特性，在进行微小目标值计量时，设备框架的振动、外力微小的扰动等都可能导致计量值的偏离，在结构紧凑、计量要求精确、工况复杂、拌合质量要求高的自密实混凝土搅拌车中，应当有更好的设计。通过多次试验验证，水、液体外加剂使用流量计进行原材料计量，很好的克服了拉式传感器的缺点。在液体计量系统中采用的流量计，其工作原理是根据电磁感应原理进行流量测量。

In the case of inevitable vibration of frame and box, in order to ensure the accurate measurement of water and liquid additives, the traditional single hanging point and pull sensor measurement method is not the best choice. The principle of liquid scale using pull type sensor as measuring element is that the gravity strain produced by measuring weight is induced and converted into electrical signal to get the weight value, which is widely used in concrete mixing station. However, due to its sensitive characteristics, the vibration of the equipment frame and the small disturbance of external force may lead to the deviation of the measurement value when measuring the micro target value. In the self compacting concrete mixer with compact structure, accurate measurement requirements, complex working conditions and high mixing quality requirements, there should be a better design. Through many tests, water and liquid admixtures are measured by flowmeter, which overcomes the shortcomings of pull sensor. The working principle of the flowmeter used in the liquid measurement system is to measure the flow according to the principle of electromagnetic induction.

当水、外加剂这类导体在磁场中做切割磁力线运动时，在管道两端的电极上产生感应电势。通过测量感应电势，结合其他已知参数换算为水或外加剂的计量重量。在流量计中，感应电压信号与平均流速呈线性关系，测量精度高；测量电极内置，抗干扰能力强；计量过程不受到振动因素影响，计量过程稳定平稳。

When conductors such as water and additives cut the magnetic lines of force in a magnetic field, an induced potential is generated on the electrodes at both ends of the pipe. By measuring the induced potential, combined with other known parameters, it can be converted into the weight of water or admixture. In the flowmeter, there is a linear relationship between the induced voltage signal and the average flow velocity, and the measurement accuracy is high; The measuring electrode is built in and has strong anti-interference ability; The measurement process is not affected by vibration factors, and the measurement process is stable.

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