The practical application of 80G Hz radar level gauge in the lime industry

The practical application of 80G Hz radar level gauge in the lime industry

Firstly,during the lime production process, a large amount of dust is generated, which poses a severe challenge to the level measurement equipment. The 80GHz radar level meter, with a 3° beam angle, has significant advantages in such a dusty environment. Taking a large lime production enterprise as an example, the lime storage bin in this enterprise has extremely high dust concentration during production, and some of it even has static electricity. The previous used level measurement equipment was severely affected by the dust and could not stably track the changes in the material level, making it difficult to accurately control the amount of materials in the storage bin during the production process, which affected production efficiency and product quality. After introducing our product 80GHz radar level meter (SLDL5280), due to its narrow beam angle and concentrated energy, it is less affected by the dust and can stably track the real-time material level. During long-term operation, it accurately provides the enterprise with real-time storage bin lime reserve information, helping the enterprise optimize the production process, improve production efficiency, and reduce production delays and resource waste caused by inaccurate material control.

1.let's introduce the characteristics of lime:

Lime production process: limestone crushing → calcination (producing calcium oxide) → digestion (reacting with water to form calcium hydroxide) → finished product storage, involving multiple stages of material level monitoring for raw materials, semi-finished products, and finished products.

Material characteristics:

(1).High dust: During crushing and calcination, a large amount of lime dust is generated, which easily covers the instrument probe and affects the measurement.

(2).High-temperature environment: The calcining kiln temperature can reach 900-1200℃, and the material temperature in the matured material storage bin often exceeds 200℃.

(3).Corrosiveness: Lime reacts with water to form calcium hydroxide, which has alkaline corrosion and may damage ordinary instruments.

(4).Diverse material forms: including blocky (limestone), powdered (lime), and slurry-like (lime emulsion).

2,Limitations of traditional measurement methods

(1).Ultrasonic level meter: Affected severely by dust, the sound wave reflection signal is weak, and the measurement error is large.

(2).Pneumatic level meter: Mechanical contact measurement, frequent maintenance, prone to clogging at high temperatures, unable to monitor in real time.

(3).Capacitive level meter: Easily affected by material humidity and agglomeration, low accuracy, and requires contact with the material, with a corrosion risk.

Second,Technical advantages of 80GHz radar level meter

1. High-frequency band characteristics suitable for complex conditions

Shorter wavelength (about 3.75mm): Compared to 26GHz radar (wavelength 11.5mm), it has stronger penetration ability through dust and is less scattered by tiny particles, suitable for the dust environment of lime.

Higher measurement accuracy: Resolution can reach ±1mm, meeting the high-precision material level control requirements (such as batching and metering) of the lime storage bin.

Smaller beam angle (3°-5°): Energy is concentrated, with strong anti-interference ability, and can avoid false echoes from obstacles in the storage bin (such as mixers, crossbeams).

2. Non-contact measurement solves the problems of high temperature / corrosion

Non-contact design: The probe does not come into direct contact with the material, so there is no need to worry about high temperatures (probe temperature resistance can reach -40℃ to 150℃, combined with high-temperature antenna, it can withstand over 300℃) or alkaline corrosion.

Maintenance-free advantage: Reduces the cleaning work caused by dust coverage and material adhesion, reducing maintenance costs by more than 50%.

3. Strong anti-interference ability, adaptable to complex bin structures

FMCW (frequency modulated continuous wave) technology: Calculates distance through frequency changes, unaffected by fluctuations in material dielectric constant (lime dielectric constant is approximately 3-5, stable and measurable).

Intelligent echo processing: Can filter out interference from material feeding impact, changes in material resting angle, etc., ensuring stable data.

Third:Practical application scenarios and cases

1. Storage bin (limestone storage)

Scenario requirements: Monitor the storage bin of blocky limestone, provide material level data for the crushing process, avoid empty bins or overflow.

Scheme advantages:

Small beam angle, can be installed at the center of the bin top, avoiding the influence of the feed inlet, reducing dust accumulation impact. The range can reach over 30 meters, suitable for tall raw material silos (common height 15-25 meters).

Case: After using an 80GHz radar level meter in a lime factory's raw material silo, the measurement error of the material level was reduced from ±10cm to ±2cm, and the automation efficiency of the crushing process increased by 15%.

2. Silica fume silo (storage of high-temperature lime)

Scene difficulty: The material temperature is 80-200℃, with dense dust. Traditional instruments are prone to malfunction due to high temperature.

Solution:

Select a high-temperature-resistant antenna (such as ceramic antenna), combined with an air sweeping device (to reduce dust accumulation).

Use a guided wave pipe installation method to guide the microwave to propagate along the pipe, avoiding interference from complex structures in the silo.

Effect: After application in the silica fume silo of an active lime production line, it operated without faults for 12 consecutive months, and the temperature fluctuation had an impact of <0.5% on the measurement accuracy.

3. Digestion tank (measurement of lime milk solution)

Scene requirements: Monitor the liquid level of slurry materials, control the proportion of water replenishment for digestion reaction.

Technical advantages:

Not affected by liquid foam (microwave can penetrate foam), measurement stability is better than ultrasonic waves.

Supports materials with low dielectric constant (the dielectric constant of the milk solution is approximately 8-10, meeting measurement conditions).

4. Finished product silo (storage of powdered lime)

Scene challenge: Powdered materials are prone to dusting, and the surface of the material level is uneven (exists an angle of rest).

Countermeasures:

Enable the "false echo suppression" function to filter out non-real echoes from the silo wall and the inclined surface of the material pile.

Combine with a PLC system to achieve material level warning, and automatically start the conveying equipment when the material level reaches the threshold.

Fourth:Comparative advantages with other technologies

Indicator	80GHz Radar Level Meter	Ultrasonic Level Meter	Plumb Bob Level Meter
Measurement Principle	Microwave reflection	Acoustic wave reflection	Mechanical contact
Dust Adaptability	Excellent (strong high-frequency penetration)	Poor (dust absorbs acoustic waves)	Medium (requires regular mechanical component cleaning)
High-temperature Adaptability	Excellent (temperature resistance -40°C to 300°C)	Poor (acoustic wave speed changes at high temperatures)	Medium (prone to jamming at high temperatures)
Maintenance Frequency	Low (1-2 times per year)	High (probe cleaning monthly)	High (mechanical structure inspection weekly)
Accuracy	±1mm~±5mm	±5mm~±50mm	±50mm~±100mm
Cost	Medium (higher equipment investment, low maintenance)	Low (cheap equipment, high maintenance)	Low (cheap equipment, high labor cost)

Fifth:Summary

The application of 80GHz radar level meters in the lime industry has solved problems such as dust, high temperature, and corrosion through high-frequency microwave technology, achieving precise material level monitoring throughout the raw material to finished product process. Its non-contact, high reliability, and easy integration features not only enhance production automation levels but also reduce maintenance costs, making it one of the key sensors for the intelligent transformation of lime production lines. When selecting, it is necessary to choose the appropriate antenna type and installation method based on specific conditions (such as temperature, dust concentration, silo size) to maximize the performance of the equipment.