Tuesday 19th Nov, 2019

VEGA’s radar solution for bulk solids

Measurement technology specialist VEGA is helping Australian companies keep track of their grain levels, even in dusty and noisy environments.

Measurement technology specialist VEGA is helping Australian companies keep track of their grain levels, even in dusty and noisy environments.

Understanding just how much grain is within a silo is often vital for accounting and logistical purposes, however due to the design of grain silos this be difficult to accurately achieve.

Radar technology has been used to collect level management readings since 2004 by producing radio waves to detect the echoes. The echoes are then detected and converted into an electronic signal which is either displayed directly on site or incorporated into a process control or management system.

However, even the smallest design or functional fault in a bulk solids level management radar sensor can have astronomical consequences for lost profits over time, meaning businesses need to implement reliable and cost-effective sensors that are able to handle these conditions.

Grain silos are often quite narrow, usually measuring in at around 60 metres in height and are commonly filled pneumatically from above and emptied at the bottom. This tends to generate a significant amount of dust and noise, impacting echo detection methods.

As it is, airborne dust is difficult to detect with radar echoes, while noise can create unfavourable reflection characteristics for the material, which potentially leads to a loss in operational efficiency.

John Leadbetter, Managing Director of VEGA Australia, says while the technology has been around for more than a decade, there was always the potential to improve it.

“With this in mind, VEGA developed the 80 gigahertz series of radars which had certain advantages over the previous 26 gigahertz series,” he explains.

“The new range were able to include a narrower beam angle and a better dynamic range to read signals better and faster.”

One of the Radar sensors released as part of this range is the VEGAPULS 69, which was the culmination of three years of research and development to respond to the market’s needs, particularly for grains handling.

Its improved dynamic range has the ability to make the returned echo a significantly stronger signal, allowing it to remain locked on to it for processing, even with constantly changing grain types.

The device was designed to be easy-to-use and able to adapt to existing process fittings, using a lens antenna instead of horns or parabolic dishes. It also contains an air purge option, allowing for periodic cleaning if required. Maintenance is kept low through an encapsulated plastic antenna or lens antenna integrated in the metal flange, making it unaffected by dust and build up.

The level transmitter operates at a frequency of 79 gigahertz, providing an enhanced focusing capacity. This helps it to reduce the influence of background noise commonly found in complex internal structures such as silos and means the beam angle is only a third of the size when compared with previous models.

Bulk solids with a poor reflective quality are also able to be measured by the system due to the addition of new microwave components, allowing it to detect even the smallest of reflected signals.

The VEGAPULS 69 has a measuring range of up to 120 metres, with an accuracy plus or minus five millimetres, giving it flexibility to be installed on almost any silo geometry. It is ideal as a replacement for mechanical measuring systems, suitable for all flange sizes and existing wiring.

Installation of the sensors is relatively simple and is usually done by supplying units with a matching flange to the exiting tank process flange, a bracket mount of open top tanks, or a threaded version.