What are the sources of error in the application of in-furnace coal belt weighers? How can they be resolved?

As a dynamic weighing instrument specifically applied in the coal flow conveying system of power plant in-furnace coal feeding, the measurement process of in-furnace coal belt weighers is influenced by working principles, external application environments, conveyor conditions, etc.

There are numerous factors that interfere with measurement accuracy, resulting in larger errors compared to static weighing instruments. What are the sources of error in the actual use of in-furnace coal belt weighers? How can these errors be eliminated to ensure the accuracy and stability of belt weighers?

The main sources of error during the determination process of in-furnace coal belt weighers include the following aspects:

1. Systematic Error

   Systematic error is the primary source of error in the measurement process of belt weighers. Its value is relatively stable and exhibits certain regularity during the measurement process, allowing for correction. After multiple measurements and averaging, the measured values of the belt weigher tend towards a certain value. Measurement device characteristic changes, inaccurate zero positions, and measurement errors caused by conveyor vibrations all fall under systematic errors.

2. Random Error

   Random errors occur during the operation of belt weighers and are caused by uncontrollable random factors, resulting in uncertain numerical variations that cannot be corrected. These errors are primarily due to environmental and natural factors, such as occasional electromagnetic interference, wind, humidity, dust, and significant temperature changes.

3. Gross Error

   This type of error is usually caused by human factors or inadequate device qualifications, leading to measurement errors in the belt weigher without any discernible pattern, often manifesting as abnormal variations in measured values.

Examples include poor installation techniques, unsuitable installation locations, abnormal material conveying methods causing excessive additional errors, variations in belt longitudinal tension, slippage caused by temperature, wear, or load effects on the belt tensioning device, and failure to conduct regular calibration and adjustment work.

It should be noted that if the maintenance and management of belt weighers are inadequate, some random errors and gross errors may become normalized , exhibiting characteristics of systematic errors in terms of numerical features, thereby affecting measurement accuracy and potentially misleading corporate data statistical analysis.

After understanding the various sources of error in in-furnace coal belt weighers, targeted measures should be taken to resolve them:

(1) Ensure that the operating environment of the belt weigher meets requirements, and the equipment must be able to adapt to on-site working conditions, conveyor belt inclination angles, and material flow rates. Consideration should be given to natural weather changes on-site, and protective measures should be taken in advance, such as equipping instruments with protective covers.

(2) When selecting equipment, choose products with strong anti-interference capabilities and durability, such as rectangular steel tube weighbridge frames, digital instruments, and sensors. Incorporate temperature sensors into compensation calculations. Taking such measures can effectively mitigate the impact of natural factors.

(3) Ensure correct installation of the belt weigher device, selecting an appropriate installation location and correctly wiring and routing. Generally, manufacturers will arrange technicians to provide on-site guidance and commissioning. Even under stringent installation conditions, they can accurately judge and ensure proper and reasonable installation of the equipment. Therefore, before selecting a product, it is also essential to clarify whether the manufacturer provides on-site installation services.

(4) Regularly maintain the belt weigher, such as checking bolt connections, sensor fixation, the flexibility of the speed measuring drum's operation, and the cleanliness of the weighbridge frame.

(5) Regularly inspect and calibrate the measurement device by comparing its data with that of more reliable weighing equipment. Analyze the measurement results, revise and optimize measurement parameters to minimize their impact on measurements. This essentially involves calibrating the belt weigher and selecting an accurate calibration method.