Today, guided wave radar measures levels where almost nothing else works: steam, extreme pressure, dust, high temperatures. In refineries, platforms, and chemical plants, it has become the benchmark. What few people know is that this reliability was born from a real problem... manufacturing...and a solution that changed level measurement forever.
Guided wave radar (GWR) level transmitters are measuring instruments based on the propagation time of the electromagnetic signal. This technology has gained traction in industry because it allows for continuous measurement of liquid and solid levels in conditions where other methods fail. High temperatures, high pressure, vacuum, the presence of steam, dense dust, or volatile gases do not compromise the reading.
Who invented guided wave radar?
The origin of guided wave radar is linked to MagnetrolA company founded in the United States led the development of this technology for industrial applications. In the late 1990s, the company launched the Eclipse Model 705, considered the first two-wire loop-powered guided wave radar level transmitter capable of measuring liquids without relying on the product's physical properties.
At the time, the real industry problem that motivated the development of guided wave radar was linked to the limitations of traditional measurement methods. In complex industrial environments, such as refineries and offshore platforms, other measurement methods frequently failed due to extreme conditions such as high pressure, elevated temperatures, the presence of steam, intense dust, and viscosity variations. These factors compromised the accuracy and reliability of readings, creating the need for a technology that could operate reliably under these challenging conditions.
The proposal attracted attention by reducing the need for frequent calibration, simplifying configuration, and allowing installation without extensive changes to existing infrastructure. The technology paved the way for more stable and predictable measurements, even in environments considered critical.
In 1998, Magnetrol introduced the Eclipse Model 705. With technological advancements, the Eclipse family has been expanded with new probe types, updated versions of the 705, and, more recently, the Eclipse Model 706, developed for more complex applications.
Eclipse is also among the safest level instruments on the market. Its Safe Failure Fraction (SFF) of over 91% allows its use in applications requiring SIL 2 compliance at the hardware level.
How does guided wave radar work?
The operation of GWR transmitters is based on time-domain reflectometry (TDR). High-frequency electromagnetic pulses travel along a probe installed in the tank. Upon encountering a change in the dielectric constant, caused by the product surface, part of the signal returns to the transmitter. Low-power electronic circuits precisely measure the time of this journey.
GWR systems support different probe configurations. Simple probes are common in liquid measurements, concentric probes are suitable for products with low dielectric constants, and flexible cables are used in tall tanks, complex structures, and bulk solids applications.
The sequence of operation can be described as follows:
The transmitter generates low-power microwave electromagnetic pulses.
These pulses travel along the guided wave probe inserted into the process.
– Upon reaching the product's surface, part of the signal returns to the transmitter.
The equipment receives the reflected pulse.
The time between sending and receiving is measured.
The level is calculated from this range and the known speed of microwaves.
The value obtained can be converted into volume or mass depending on the tank geometry and the product density.
Applications of GWR transmitters
Guided wave radar level transmitters are used in:
Oil/gas interface measurement in separators
- Crude oil tanks
- Offshore drilling platforms
- Acid and alkali tanks in the chemical and petrochemical industries.
- Reaction vessels subjected to high temperatures and pressures.
They also appear in:
- Water and sewage treatment reservoirs
- Chemical dosing tanks
- Sludge and foam detection
In the food, beverage, and pharmaceutical sectors, they are employed in:
- Tanks for syrups, oils and milk
In power generation and sanitation, they are used in:
- Boiler feed tanks
- Condensate and refrigerant monitoring
- Black liquor, slurry and storage tanks
Magnetrol guided wave radar models
The Eclipse 706 was designed for the most demanding industrial processes. Powered by a 24 VDC loop, it measures level, interface, and volume even with steam, foam, or product adhering to the probe. The universal connector allows the use of different types of probes, expanding installation possibilities.
The model also integrates with digital configuration and maintenance systems via FDT/DTM and enhanced DD. The dual-compartment enclosure, with a graphic LCD display, facilitates electrical installation and parameter navigation. In safety instrumented applications, the 706 is frequently used due to its SIL 2 and SIL 3 certifications.
The Eclipse 700 utilizes the same guided wave radar measurement principle, focusing on direct field operation. The equipment performs continuous measurements up to the process seal when combined with overflow probes, without the need for additional algorithms. This feature is advantageous in tanks where operational simplicity and reliability are priorities.
The Eclipse 700 interface was designed for local use. The four-button keypad and graphic LCD screen allow for transmitter configuration at the installation point, with access to the echo curve and diagnostic messages to assist the operator.
In a direct comparison, the Eclipse 706 is suitable for plants that require greater connectivity and configuration flexibility. The Eclipse 700 remains present in applications where direct measurement, simple operation, and less dependence on external tools guide the choice. The decision between one model and the other is linked to the level of complexity of the process and the degree of automation of the plant.
History of Magnetrol
Magnetrol's history began in 1932, when the Chicago-based company started as a manufacturer of boiler systems. The first level controller emerged when the founding company, Schaub Systems Service, needed a controller for its boiler systems. This demand led to the brand's first level controller, based on mechanical buoyancy principles, a technology that quickly became a benchmark in industrial applications.
Over the following decades, Magnetrol consolidated its presence in critical processes, expanding its portfolio beyond mechanical buoyancy. The company began investing in electronic measurement solutions, keeping pace with the evolution of industrial plants and the increasing complexity of processes.
This move led to Magnetrol's definitive entry into the field of industrial radar in the late 1990s. In 1998, the company launched the Eclipse Model 705, the first loop-fed guided wave radar transmitter developed for industrial liquid level applications. The equipment set a new standard by offering stable measurements, independent of product properties and suitable for harsh environments.
In the following years, the technology evolved rapidly. In 1999, Magnetrol introduced guided wave radar probes capable of operating at high temperatures and pressures. In 2000, it introduced coaxial probes designed to withstand overload conditions. Then, in 2001, it pioneered the integration of guided wave radar with magnetic level indicator chambers, creating truly redundant measurement systems.
Alongside the development of GWR, Magnetrol expanded its operations into complementary technologies such as non-contact pulse radar, radio frequency capacitance, and ultrasound. This diversification has allowed it to meet increasingly complex industrial applications, while maintaining a focus on reliability, operational safety, and measurement accuracy.
Where can I buy guided wave radar with guaranteed commissioning and training in Brazil?
Magnetrol's Eclipse transmitters are part of Alutal's portfolio – the brand's exclusive distributor in Brazil – and are used in plants that require precise control of liquid and solid levels. Among the most sought-after models are the Eclipse 706, designed for more complex applications, and the Eclipse 700, an earlier version still present in many operations.
Those seeking guided wave radar with reliable supply, guaranteed commissioning, and training in Brazil will find Alutal to be a leading reference in the industrial market. The company acts as a distributor of guided wave radar and offers a portfolio of proven equipment for level measurement in critical applications, with local technical support and a history of long-term partnerships with international manufacturers.
One of the company's attractive features is its comprehensive service package. In addition to selling guided wave radar, Alutal offers application engineering, commissioning, calibration, and assisted installation, ensuring that the equipment operates according to the design and real-world process conditions. This support reduces the risk of specification errors and increases measurement reliability over time.
