1、 Volumetric batching method: with "volume conversion" as the core, focusing on low cost and high efficiency

The core logic of volumetric batching method is to convert the "weight requirement" required for concrete proportioning into the "volume parameter" of materials, and achieve measurement by controlling the filling amount of materials in a fixed volume space without direct weighing. The core components are mostly material hoppers, screw conveyors or belt conveyors with volume adjustment function.

1. Working principle

Firstly, based on the bulk density of each material (such as sand, stone, cement), convert the required "weight" of the concrete mix ratio into "theoretical volume" (for example, the bulk density of cement is about 1300kg/m ³, and if 50kg of mix is required, the corresponding volume is about 0.038m ³); By adjusting the height of the baffle in the hopper, the speed or duration of the conveyor, the volume of the material transported each time can be accurately matched with the theoretical calculation value; Finally, the material is fed into the mixing machine to complete a single batching cycle.

2. Characteristics of homework

From the perspective of advantages, the equipment structure of the volumetric batching method is simple, without the need for high-precision weighing sensors. The manufacturing and maintenance costs are only 50% -70% of those of the weight based method, making it more friendly to small and medium-sized mixing plants; At the same time, the batching process does not require waiting for weighing feedback, and materials can be continuously transported. The batching time for a single batch is reduced by 20% -30% compared to weight based methods, making it suitable for mass production scenarios; And the operation threshold is low, without the need for complex weighing calibration. Only the volume parameters need to be set according to the material density, and beginners can quickly get started.

From a limitation perspective, this method has low measurement accuracy and is greatly affected by material characteristics - for example, changes in the moisture content of sand and stone can lead to changes in bulk density (wet sand has a 10% -15% lower bulk density than dry sand), which can result in a mix deviation of ± 3% -5%; The material adaptability is also poor, only suitable for materials with uniform particles and stable density (such as gravel, dry sand). For fine powder materials such as cement and fly ash, it is easy to further reduce accuracy due to "bridging" (material blockage of the conveying port) or "leakage"; In addition, the flexibility of ratio adjustment is low. If the material type is changed (such as from fine sand to coarse sand), the bulk density needs to be recalculated and the volume parameters adjusted, otherwise the deviation will significantly increase.

3. Applicable scenarios

Mainly used for projects with low requirements for concrete strength grade (such as rural roads, self built building building cushion layers), with a suitable strength of C15-C25; Suitable for small and medium-sized mixing plants or mobile mixing plants with a single batch output of ≤ 5m ³ and an average daily output of ≤ 50m ³, it stands out in cost-effective scenarios with limited budget and low precision requirements.

2、 Weight based batching method: with "direct weighing" as the core, focusing on high precision and wide adaptability

The weight based batching method directly measures the weight of materials through high-precision weighing sensors, feeds back the weight data to the control system in real time, compares it with the set value, and automatically stops feeding after reaching the target weight. It is currently the mainstream method to ensure the quality of concrete. According to different weighing objects, it can be further divided into "cumulative weighing" and "individual weighing" - cumulative weighing is when multiple materials enter the same weighing hopper in sequence (such as sand, stone, and cement), and sensors accumulate to calculate the total weight; The separate type is equipped with independent weighing hoppers for each material, which are weighed separately and synchronously fed into the mixing machine for higher efficiency.

1. Working principle

First, set the "target weight" for each material in the control system (such as 50kg cement, 100kg sand, 150kg stone); The material is fed into the weighing hopper through vibrating feeders, spiral feeders, etc. The sensor collects the weight of the hopper in real time and transmits it to the control system; When the actual weight approaches the target weight (such as reaching 90%), the system automatically switches to the "precision feeding" mode (reducing the feeding speed) to avoid weight overshoot; When the actual weight matches the target weight, the feeder stops and the material is unloaded into the mixing machine to complete the batching process.

2. Characteristics of homework

In terms of advantages, the weight based batching method has extremely high measurement accuracy and is not affected by changes in material bulk density or moisture content. The mixing deviation can be controlled within ± 0.1% -0.5%, which can meet the quality requirements of high-strength concrete (C30 and above); Wide material adaptability, suitable for various concrete materials such as sand, stone, cement, fly ash, additives, etc. Even if there is slight bridging of fine powder materials, the feeding amount can be adjusted in a timely manner through weight feedback to avoid deviation; At the same time, the ratio adjustment is flexible. When changing materials or modifying the ratio, only the target weight needs to be directly modified in the control system, without the need to recalculate parameters, which is suitable for the production of multiple types of concrete.

The limitation is that the equipment cost is relatively high, requiring high-precision weighing sensors, stable weighing brackets (to avoid vibration interference), and complex control systems. The cost is more than 50% higher than that of capacitive type; The efficiency of homework is slightly low, especially for cumulative weighing, which requires multiple materials to be weighed sequentially. The batching time for a single batch is 10% -20% longer than that of volumetric weighing (individual weighing can alleviate efficiency issues by synchronously weighing multiple hoppers); And the maintenance requirements are high. The weighing sensor needs to be calibrated every 3-6 months, while avoiding environmental interference such as severe vibration and dust coverage, otherwise it is easy to cause accuracy degradation.

3. Applicable scenarios

The core is used for projects that require high strength and stability of concrete, such as high-rise buildings, bridges, tunnels, and water conservancy projects, with a suitable strength range of C30-C60; Suitable for large and medium-sized mixing plants or commercial concrete mixing plants with a single batch output of ≥ 5m ³ and an average daily output of ≥ 100m ³, especially in scenarios where frequent switching of mix proportions and production of multi specification concrete are required, it can maximize the guarantee of quality stability.

If your project requires the configuration of a concrete automatic batching machine and the target concrete strength grade is specified (such as C30 bridge concrete), do you need me to help you sort out the specific parameter setting suggestions for the weight based batching machine in this scenario?