To achieve accurate measurement of Mobile Screw Conveyor, breakthroughs must be made in hardware design, control system, and dynamic calibration. Combining material characteristics with scenario requirements, multi-sensor fusion and algorithm optimization are used to control the measurement error within the range of ±0.5%-±2%. The specific solution is as follows:
1. Hardware layer: integration of high-precision measurement components
Rigid coupling design of weighing module
High-precision strain gauge weighing sensors (accuracy level C3, sensitivity 2mV/V) are installed at the feeding end and the discharging end of the screw shaft respectively, and are rigidly connected to the frame through a fully suspended bracket to avoid vibration interference (error <0.3% when vibration frequency ≤5Hz).
Case: A chemical equipment is equipped with 4 sets of weighing sensors with a range of 0-50t/h, which can collect the instantaneous weight of materials in real time with a resolution of 0.1kg.
Precise control of screw shaft speed
It is driven by a servo motor + planetary reducer (speed control accuracy ±0.1r/min), and the encoder is used to feedback the screw shaft speed in real time (pulse resolution 10000ppr). For example, when conveying grains, the speed range is 5-30r/min, corresponding to a conveying volume of 0.5-15m³/h, and the speed fluctuation is <0.5%.
Anti-skid and stable feeding structure
A material level meter (such as ultrasonic or radar) is set at the feed inlet. When the material level in the silo is lower than the set value (such as 10cm), the refill signal is automatically triggered to avoid metering fluctuations caused by material shortage.
The spiral blades are designed with equal pitch and equal diameter (error ±0.2mm), and the inner wall of the casing is polished (roughness Ra≤1.6μm) to reduce material retention and sliding and ensure uniform transportation.
2. Software layer: dynamic metering algorithm optimization
Material transport model establishment
The metering system is built through PLC + industrial computer, with a built-in material property database (including bulk density, moisture content, and fluidity index). For example, when conveying cement (density 1.3t/m³) and sand (density 1.6t/m³), the system automatically calls the corresponding parameters and calculates the theoretical conveying volume (formula: Q=π(D²-d²) Snρ/4, where D is the inner diameter of the casing, d is the diameter of the screw shaft, S is the pitch, n is the speed, and ρ is the material density).
Real-time error compensation technology
The Kalman filter algorithm is used to fuse the weighing data and the speed data, filter out high-frequency noise (such as weight fluctuation caused by equipment vibration), and output smooth instantaneous flow and cumulative amount;
When the cumulative error exceeds ±1%, the system automatically triggers the dynamic calibration procedure: inject a standard weight (such as 50kg) through the feed port, compare the theoretical value with the actual measurement value, and correct the screw shaft speed coefficient (K value). The calibration period can be set to 1-8 hours.
3. Scenario Adaptation and Verification Mechanism
Multi-mode metering switching
Volumetric measurement mode: suitable for materials with good fluidity and stable density (such as grains), with an error of ≤±1.5%;
Weighing and metering mode: suitable for materials with large density fluctuations or precious materials (such as chemical raw materials), with an error of ≤±0.8%. The mode is switched by switching the opening of the feed gate.
Traceable calibration system
Equipped with a portable calibration device (such as a standard weight box + calibration software), it supports fast on-site calibration: lay the weights evenly on the screw shaft, run the equipment to simulate material transportation, and the system automatically calculates the linearity error (required to be ≤±0.5%). The calibration records can be stored and traced (storage period ≥1 year).
Data comparison: After upgrading a mobile screw conveyor in a grain storage facility, when conveying wheat (density 0.75t/m³), the cumulative measurement error was reduced from ±3% to ±0.9%, and the maximum deviation per hour was reduced from 180kg to 54kg, meeting the accuracy requirements of ISO 9001:2015 for measurement equipment. The core is to solve measurement difficulties such as vibration interference, material changes, and equipment posture fluctuations in mobile scenarios through a three-dimensional system of "hardware rigid support + software intelligent compensation + scene dynamic adaptation".
If you want to know how Mobile Screw Conveyor can achieve accurate measurement , you can consult our customer service staff, we will serve you wholeheartedly 24 hours a day!