SONO VARIO Radar Moisture Meter

The SONO VARIO series from IMKO is a family of industrial radar moisture meters designed for highly accurate measurement of moisture in abrasive bulk solids such as sand, gravel, crushed stone and other construction aggregates. The sensors feature replaceable probe heads, adjustable probe lengths and extremely robust materials (hardened steel, special ceramic, optional carbide or V4A). The range includes Standard, Xtrem, Mix, SILO and high-temperature ES versions. All models provide continuous online monitoring with high long-term stability and require no recalibration for most materials.

Operating Principle

SONO VARIO uses patented TRIME® TDR (Time Domain Reflectometry) radar technology: a short electromagnetic pulse is transmitted along the probe into the material. Water strongly influences the dielectric constant (εr), which changes the signal propagation speed and reflection time. The sensor calculates moisture (and optionally conductivity) from the runtime with picosecond resolution. An integrated temperature sensor automatically compensates for temperature effects; averaging modes and optional ultrasonic density measurement ensure stable readings even in dynamic conditions.

Specifications by Model

SONO VARIO Standard

• Materials: Stainless steel probe

• Temperature: 0…+70 °C

• Outputs: 2 × 0(4)…20 mA (moisture + temperature/conductivity)

• Power: +12…+24 V DC, ~3 W

• Protection: IP67

• Interfaces: RS485 or IMP bus

• Dimensions: Ø108 × 71 mm (without connector)

• Application: General-purpose for non-extreme abrasive materials

SONO VARIO Xtrem

• Materials: Replaceable hardened steel probe head with special ceramic window

• Temperature: 0…+70 °C (standard), up to +120 °C (high-temperature version)

• Outputs: 2 × 0(4)…20 mA

• Power: +12…+24 V DC, ~3 W

• Protection: IP67

• Weight: 2.46 kg

• Features: Rectangular or round sensor versions, rod-type available; designed for highly abrasive materials (sand, gravel)

SONO Mix / SONO Mix Mini

• Materials: Stainless steel with ceramic surface

• Temperature: 0…+70 °C

• Outputs: 2 × 0(4)…20 mA (moisture + density/temperature)

• Features: Automatic density compensation; ideal for inhomogeneous or mixed bulk solids

SONO SILO / SONO SILO Standard

• Materials: Stainless steel with flange mounting

• Probe length: Adjustable up to 2 m

• Features: Specifically for vertical installation in silos and hoppers

SONO ES VARIO Xtrem

• Materials: Hardened steel + ceramic; optional carbide (308090) or V4A (308101)

• Temperature: Up to +120 °C (with external ES converter)

• Features: High-temperature and Ex versions available; for extreme abrasion and heat

Main Application Areas

Continuous moisture monitoring of abrasive construction materials (sand, gravel, crushed stone) in concrete plants, cement production, road construction and aggregate processing. Typical mounting locations: under silo gates, on dosing belts, in conveyor discharge hoppers and mixers. Also used for biomass and other non-adhesive bulk solids in the energy sector.

Advantages of the SONO VARIO Radar Moisture Meter

• Extremely long service life in highly abrasive environments thanks to replaceable probe heads (ceramic, carbide or V4A)

• Outstanding accuracy and long-term stability without recalibration

• Automatic temperature (and optional density) compensation

• Adjustable probe length and multiple mounting accessories

• Versions for high temperatures and ATEX zones

• Easy integration via analogue and digital interfaces

• Minimal maintenance and > 10-year service life even under toughest conditions

• Significant cost savings through precise dosing and reduced waste