Sensitive UWT Measurement Solutions for Pneumatic Conveying and Storage of Ultra-Fine Silicon Dioxide

UWT GmbH 5 hours ago

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Nivoradar Nr3300_Front Tilted Right_Bottom Tilted — NR 3300 Ensures Long-Term Stable Measurements in Powder Applications with Purge Air Connection and Precise Alignment

Precise Radar and Vibration Sensor Technology for Silica Insulation Production

UWT GmbH measurement solutions are supporting reliable level control in demanding bulk solids applications, including the pneumatic conveying and storage of ultra-fine silicon dioxide in insulation material production.

Silicon dioxide, also known as silica, is used across many industries, from paint and plastics manufacturing to food and pharmaceutical production, and in the manufacture of modern insulation materials. In chemical process engineering in particular, this fine-grained and often fluidised powder places high demands on storage vessels, pneumatic conveying systems and level measurement technology.

A recent insulation material production project demonstrates how UWT sensor solutions operate reliably even with extremely fine-grained and pneumatically conveyed silica. Despite heavy dust loads and very low bulk density, the sensors enable precise and process-secure continuous level measurement and point level detection.

Nivoradar Nr3300_Bottom_Tilted — NR 3300 Ensures Long-Term Stable Measurements in Powder Applications with Purge Air Connection and Precise Alignment

Reliable Level Measurement in 25 m Silos Handling Fluidised Silica

In a plant producing heat and sound insulation boards, highly dispersed silica SiO₂ is temporarily stored in vertical stainless steel silos approximately 25 m high before further processing. The objective was accurate material detection for both continuous inventory monitoring and point level control.

The Application: Combined Continuous and Point Level Measurement

Each silo required three critical measurement tasks:

Continuous level measurement for inventory monitoring
Point level detection for full and empty indication to control filling and discharge cycles
Material flow monitoring in the discharge pipe for early detection of blockages and bridging

This combination of radar level measurement and vibrating level sensors ensures complete visibility of the storage and discharge process.

Vibranivo Vn2 Vibrasil 70_Lying Down_Bright — VN 2020 with the Sensitive Vibrasil® 70 Probe Detects Even the Lightest Materials

The Challenge: Fluidised Silica with Extremely Low Bulk Density

During pneumatic conveying, the silica is fluidised and blown into the silo. The air supply aerates the ultra-fine powder, resulting in extremely low bulk density and high dust generation.

In this fluidised state, the material provides only minimal radar reflection and almost no mechanical resistance. Conventional level sensors often struggle under these conditions. After filling, the material settles in the silo and during pneumatically assisted discharge forms a typical conical pile. This geometry increases the risk of bridging and flow interruption.

Process Conditions at a Glance

Parameter	Specification
Medium	Highly dispersed silica SiO₂, pneumatically fluidised
Silo	Stainless steel, approx. 25 m high
Bulk density	< 20 g/l
Process temperature	Ambient to +60 °C
Explosion protection	ATEX Zone 21
Special conditions	High dust load, low dielectric constant, conical pile formation

Given the presence of potentially explosive dust atmospheres, ATEX-compliant instrumentation is essential for safe operation in UK and European process plants.

Nivoradar Nr3300_Levelapp — UWT LevelApp Enables Easy Configuration and Commissioning

The Solution

NivoRadar® NR 3300: 80 GHz Radar for Continuous Level Measurement

For continuous level measurement, the NivoRadar® NR 3300 with lens antenna was selected because it provides precise and stable results even under demanding conditions such as fluidised silica with a very low dielectric constant.

Key advantages at a glance:

3° beam angle using 80 GHz radar technology, ideal for tall and narrow silos
Swivel flange in stainless steel, adjustable up to ±10°, enabling precise alignment towards conical bulk solids piles and funnel-shaped silo outlets
UWT LevelApp with alignment assistant for visual adjustment and simple commissioning via smartphone
Purge air connection with check valve to keep the antenna free from fine dust and prevent material ingress
Robust materials such as 316L stainless steel, PEEK and FKM, relevant for silica in sensitive industries including food and pharmaceutical

Thanks to the adjustable flange, the radar sensor was aligned so that the beam precisely captures the bulk cone and extends down to the conical silo bottom. The integrated purge air function reliably prevents dust build-up on the lens antenna, particularly during filling, ensuring consistently accurate measurement results in high dust environments.

For UK operators seeking reliable radar level measurement in bulk powder silos, the 80 GHz technology provides stable signals even with low reflectivity media such as silica.

Nivoradar Nr3300_Levelapp Calibration — Visual Alignment Assistance During Installation – Easily via UWT LevelApp

Vibranivo® VN 2020 with Vibrasil®: High-Sensitivity Point Level Detection

For point level detection of full and empty conditions and discharge monitoring, the plant relies on the proven Vibranivo® VN 2020 with Vibrasil® technology.

The specially developed Vibrasil® probe is designed for very light and pneumatically conveyed bulk solids including powders and silica. With high sensitivity and rapid switching response, it ensures reliable detection even with materials that have a bulk density of less than 5 g/l.

Full Detection with Fluidised Silica

At the insulation material manufacturer, the VN 2020 with Vibrasil® 70 was installed as a full detector beneath the silo roof. Because the silica is fluidised during pneumatic conveying, a highly sensitive point level sensor is essential.

The vibrating probe, equipped with an additional paddle, significantly increases the active surface area. This allows the sensor to reliably detect even airborne material with extremely low bulk density, ensuring dependable high-level alarm functionality.

Nivoradar Nr3_Vibranivo Vn2_Vibrasil70_Silo Pneumatic — Reliable Level and Point Level Detection in All Silo Areas with Fluidized Silica: NR 3300 and VN 2020 with Vibrasil® Probes Ensure Process-Stable Measurement Solutions for the Lightest Materials in All Silo Sections

Empty Detection in the Cone Area

In the lower section of the silo, the Vibrasil® 90 version is used as an empty detector. Its polished and extended tuning fork offers high sensitivity, slightly lower than the Vibrasil® 70 version, yet still reliably detects when the silo is empty as soon as the fork is uncovered.

Installation is straightforward and maintenance-friendly, carried out externally via a 1½ inch socket. This simplifies servicing while maintaining ATEX compliance.

Discharge Branch Monitoring During Pneumatic Conveying

The Vibranivo® with Vibrasil® 70 is also installed in the discharge branch. Additional discharge aids such as mechanical vibration and pneumatic assistance help maintain material flow.

The sensor continuously monitors the discharge pipe, ensuring that the conveying process for this extremely light material remains uninterrupted. Early detection of bridging or blockage helps prevent downtime and protects downstream equipment.

ATEX-Compliant Measurement for Explosive Dust Atmospheres

Fine and dry silica can form an explosive dust atmosphere under certain conditions, particularly during pneumatic conveying or injection processes. Hazardous areas classified as ATEX Zone 21 are therefore common in silica handling applications.

Both the NivoRadar® 3300 and the Vibranivo® carry international Ex certifications, providing maximum process safety and regulatory compliance for insulation manufacturers and chemical processing facilities.

Result: Stable and Reliable Process Control from Filling to Discharge

By combining continuous radar level measurement with high-sensitivity vibrating point level detection, complete monitoring from filling and storage through to discharge was achieved.

Despite heavy dust, fluidising air and extremely low bulk density, the sensors consistently deliver stable signals. Maintenance requirements were significantly reduced and overall process reliability was improved.

This silica storage application clearly demonstrates that whether using radar or vibrating measurement technology, UWT offers a suitable solution for demanding bulk solids handling applications. Advanced sensor technology, practical installation features and intelligent commissioning tools ensure reliable process performance, even when handling ultra-fine and difficult powders in modern UK process industries.

UWT GmbH
Westendstr.5
87488 Betzigau, Germany
info@uwtgroup.com
www.uwtgroup.com