Industrial Radar Sensors: Precise Level Monitoring and Fill Level Control

Industrial Radar Sensors have established themselves as one of the most reliable technologies for level control in recent years. Its versatility and efficiency make it the preferred solution in industries such as food and beverages, chemicals, pharmaceuticals, and energy supply. This article explores the key principles, advantages, and applications of radar measurement, highlighting the benefits that different technologies can offer for specific challenges.

Basic Principles of Measurement using Radar Sensors

Radar, short for “radio detection and ranging”, operates on the transmission and reflection of electromagnetic waves. An industrial radar sensor emits a focused electromagnetic wave, which is reflected back by objects as an echo and then analysed by the sensor.

This principle enables the precise measurement of distances, levels, or positions. The radar category includes both free-radiating industrial radar sensors and sensors based on guided microwave technology, commonly referred to as guided radar, TDR (Time Domain Reflectometry), or GWR (Guided Wave Radar) sensors.

Free-radiating industrial radar sensors operate contact-free, transmitting electromagnetic waves towards the medium to be measured using specific types of antennas. These sensors are generally characterised by their frequency, as it plays a crucial role in non-contact level measurement within process or storage containers.

• High-Frequency Technology: Industrial radar sensors with high frequencies, such as 80 GHz technology, can be designed compactly, feature narrow beam angles of up to 3°, and provide excellent reflection properties. This enables them to deliver precise and reliable measurement results, even in complex tank geometries or confined shafts and pipes.
  
• Typical Applications: They are ideal for liquids and bulk solids in silos, tanks, and open containers, particularly in situations where non-contact measurement is preferred due to hygiene or process requirements.

Guided industrial radar sensors, also known as TDR or GWR sensors, use a probe (rod or cable) as a waveguide. The signal is directed along this guide directly to the medium. The probe remains in contact with the medium, offering specific advantages in demanding applications.

• Low-Frequency Technology: Guided radar sensors often operate at very low frequencies (e.g., 1 GHz), making them particularly resistant to dust, build-up, foam, or steam. This makes them ideal for applications involving moving surfaces or interface measurements.
• Customisable Probe Types: Various options, such as rod probes, cable probes, or coated probes (e.g., PA), allow flexible adaptation to specific process requirements.
• Typical Applications: They are particularly suited for challenging process environments, such as highly dusty environments within silos or tanks containing aggressive media.

Adapting to Different Media

In addition to the measurement principles, distinctions are also made based on the various properties of the measured media:

Liquids
80 GHz radar technology provides versatile solutions for the precise level measurement of liquids. Smooth surfaces and high reflectivity ensure clear signals and straightforward measurement. The narrow beam angle of high-frequency industrial radar sensors enables accurate detection, even in narrow tanks or with turbulent surfaces.

Bulk Solids
Bulk solids pose greater challenges to sensors due to irregular surfaces, dust generation, and material cones. Modern radar systems excel in these conditions with robust signal processing that delivers precise measurements even under such demanding circumstances.

The combination of high temperature and pressure resistance, minimal dead zones, and measurement accuracy of up to ±2 mm makes this technology the ideal choice for dusty environments within silos or complex bulk material processes.

Advantages of Radar Technology

Radar measurement offers numerous advantages, making it particularly attractive for demanding applications:

High Measurement Accuracy: Industrial radar sensors provide precise results, even under challenging conditions such as extreme temperatures, high pressure, or aggressive media. This ensures reliable process control and quality assurance.

Non-Contact Measurement: Radar technology is characterised by exceptionally high measurement accuracy and delivers precise results without requiring physical contact with the medium.

Maintenance-Free Operation: Since measurement is either non-contact or conducted via a guided wave, wear and mechanical failures are virtually eliminated. This extends the lifespan of the systems and minimises maintenance costs.

Resistance to Contamination: Industrial radar sensors measure reliably even when dirt or build-up forms on the sensor. Optimised signal processing filters out interference, eliminating the need for cleaning.

Independence from Process and Environmental Influences: Temperature, pressure, vacuum, and challenging conditions such as fog, wind, or rain do not affect measurement accuracy. The sensors provide reliable results under all environmental conditions.

High Level of User-Friendliness: The simple setup and optional sensor configuration, such as via an app, save time and enable quick commissioning and diagnostics.

Measurement in Flooding Conditions: Industrial radar sensors enable reliable measurement up to the sensor antenna, even in flooding situations. They have no dead zone, require no protective covers, and remain operational even in such extreme conditions.

Excellent Signal Focusing: The 80 GHz technology enables pinpoint alignment of the radar beam on the medium to be measured. This simplifies the separation of measurement and interference signals, making measurement easy and accurate even in narrow shafts or with installations such as pipes and pumps.

Flexibility: Radar technology is highly versatile, suitable for a wide range of applications – from silos containing solids and liquid tanks to complex process systems or open-air applications like outdoor stockpiles. This reduces the need for multiple sensor types and simplifies system planning.

Applications in Various Industries

Food and Beverage Industry
In food production, hygiene and accuracy are top priorities. Industrial radar sensors are often used to measure liquids such as milk, juices, or sauces. Their non-contact operation minimises the risk of contamination.

Additionally, their resistance to temperature fluctuations and foam formation ensures reliable process control. The benefits include maintaining consistent product quality and reducing production downtime.

Chemical Sector
In chemical production, sensors must operate under extreme conditions. Radar technology excels in handling high temperatures, aggressive media, and explosive atmospheres.

A typical application is measurement in reactors or storage tanks for acids and solvents. Here, radar measurement helps minimise safety risks and improve the efficiency of complex processes.

Pharmaceutical Industry
Precise measurements and easy cleaning are crucial in this sector. Guided radar sensors, designed to meet the high demands of sterile processes, deliver excellent results.

They are often used in fermentation processes or for level monitoring of active ingredients. The greatest advantage is their ability to support strict regulatory requirements and ensure the highest product purity.

Energy and Utilities Sector
In coal power plants or biogas facilities, sensors often need to handle abrasive or difficult-to-measure materials. Industrial radar sensors have proven effective in measuring coal, ash, or biomass, contributing to increased efficiency and operational safety. This enables optimised resource utilisation and a reduction in operating costs.

Radar Technology – Future-Proof and Versatile

In summary, radar measurement is an indispensable key technology for modern process industries. It combines accuracy, reliability, and flexibility, proving its worth in a wide range of applications – from hygiene-sensitive processes to extreme industrial environments.

With the continuous advancement of industrial radar sensors, this technology remains a cornerstone for process optimisation and efficiency improvements across industries.

FAQs: Industrial Radar Sensors for Accurate Level Monitoring

What are industrial radar sensors used for?
They measure fill levels of liquids or solids in tanks silos and process vessels across industries

How do radar sensors work?
They emit electromagnetic waves which reflect off the medium and return to the sensor for level calculation

What’s the difference between free-radiating and guided radar sensors?
Free-radiating sensors measure without contact while guided radar sensors use a probe for direct signal guidance into the medium

Why use 80 GHz radar technology?
It enables narrow beam angles for pinpoint accuracy in tight or complex tank geometries

What are guided radar sensors best suited for?
They perform well in dusty foamy or turbulent environments where contact measurement is more reliable

Can radar sensors handle aggressive media or extreme conditions?
Yes they are resistant to high pressure temperature build-up and harsh chemicals

Do radar sensors require a lot of maintenance?
No they are typically maintenance-free due to non-contact operation and robust signal processing

What industries use industrial radar sensors?
Food and beverage chemical pharmaceutical energy utilities and more

Are radar sensors hygienic for food applications?
Yes non-contact design and cleanability make them ideal for hygienic processes

How do radar sensors contribute to safety and efficiency?
They provide reliable data for automated control systems reducing risks downtime and product waste