MOLOSroto DF Rotary Level Indicators

MOLOSroto DF is a series of rotary level indicators from Mollet designed for precise monitoring of bulk solids in silos, hoppers, and other containers. They reliably detect “full” and “empty” states even under extreme conditions: process temperatures up to 1000 °C, pressures up to 100 bar, and in explosive atmospheres (ATEX dust and gas). The series includes compact stainless steel models adapted for heavy loads, sticky materials, high pressure, vibration, and interface measurement. A wide range of versions (from basic to highly specialized) ensures versatility, easy installation, and maintenance-free operation.

Operating Principle

MOLOSroto DF rotary level indicators operate using a motor-driven rotating paddle. When the paddle is uncovered (material level below the sensor), it rotates continuously. When material contacts the paddle, rotation stops, triggering a microswitch and generating a signal (contact change). Once the material level drops, the motor returns the paddle to its original position. The system is insensitive to pressure, temperature, dust, adhesion, or material conductivity, ensuring reliable level detection.

General Characteristics by Type

DF11

• Materials: Housing – aluminium (IP66); shaft and paddle – stainless steel or plastic

• Certifications: Ex II 1/2D IIIC, Ex II 1/3D IIIB (dust)

• Temperature: Ambient –20…+70 °C; Process –25…+80 °C

• Pressure: –0.5…+1 bar

• Paddles: Stainless steel or plastic

• Other: Supply 230/115/48/24 V AC or 24 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Any/vertical mounting; Maintenance-free

DF21

• Materials: Housing – aluminium (IP66); shaft and paddle – stainless steel or plastic

• Certifications: Ex II 1/2D IIIC, Ex II 1/3D IIIB (dust)

• Temperature: Ambient –20…+70 °C; Process –25…+500 °C

• Pressure: –0.5…+25 bar

• Paddles: Stainless steel or plastic

• Other: Supply 230/115/48/24 V AC or 24 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Any/vertical mounting; Maintenance-free

DF22

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/VITON/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust)

• Temperature: Ambient –40…+70 °C; Process –25…+80 °C

• Pressure: –1…+10 bar

• Paddles: Stainless steel (suitable for light deposits)

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Any mounting position; Connection length up to 200 mm

DF23

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust); Ex II 2G IIB/IIC + II 1/2D IIIC (gas+dust)

• Temperature: Ambient –40…+70 °C; Process –40…+260 °C

• Pressure: –1…+25 bar

• Paddles: Stainless steel (for heavy materials)

• Extreme shaft load: up to 390 Nm

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Any mounting position; Shaft up to 2000 mm

DF24

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust); Ex II 2G IIB/IIC + II 1/2D IIIC (gas+dust)

• Temperature: Ambient –40…+70 °C; Process –40…+260 °C

• Pressure: –0.5…+5 bar

• Paddles: Stainless steel

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Any mounting position; Cantilever up to 1500 mm; Flanged connection

DF25

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/VITON/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust); Ex II 2G IIB/IIC + II 1/2D IIIC (gas+dust)

• Temperature: Ambient –40…+70 °C; Process –40…+260 °C (up to +350 °C on request)

• Pressure: –0.5…+5 bar

• Paddles: Stainless steel (for high loads)

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Horizontal mounting; Rigid extension up to 500 mm

DF26

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/VITON/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust); Ex II 2G IIB/IIC + II 1/2D IIIC (gas+dust)

• Temperature: Ambient –40…+70 °C; Process –40…+500 °C (up to +1200 °C on request)

• Pressure: –1…+25 bar (up to 100 bar on request)

• Paddles: Stainless steel (pendulum type)

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Vertical mounting; Shaft up to 1500 mm; Bend protection

DF27

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/VITON/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust); Ex II 2G IIB/IIC + II 1/2D IIIC (gas+dust)

• Temperature: Ambient –40…+70 °C; Process –40…+500 °C (up to +1200 °C on request)

• Pressure: –1…+25 bar (up to 100 bar on request)

• Paddles: Stainless steel (for interface measurement)

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Vertical mounting; Rope extension up to 10 000 mm

DF28

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; Protective tube – stainless steel (up to 6000 mm); seals – NBR/VITON/PTFE/Graphite

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC, Ex II 1/3D IIIB (dust); Ex II 2G IIB/IIC + II 1/2D IIIC (gas+dust)

• Temperature: Ambient –40…+70 °C; Process –40…+500 °C (up to +1200 °C on request)

• Pressure: –1…+25 bar

• Paddles: Stainless steel

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Vertical mounting; For filling streams

DF30

• Materials: Housing – aluminium/stainless steel (IP66); shaft and paddle – stainless steel; seals – NBR/VITON/PTFE

• Certifications: Ex II 1/2D IIIC, Ex II 1D IIIC (dust)

• Temperature: Ambient –40…+70 °C; Process –40…+80 °C

• Pressure: –0.5…+5 bar

• Paddles: Stainless steel (for conical outlets)

• Other: Supply 230/115/48/24 V AC / 48/24/12 V DC; Contact 1 mA/4 V DC…2 A/250 V AC; Vertical mounting (from 100 mm); Fast response time

Main Application Areas

MOLOSroto DF rotary level indicators are used for monitoring bulk solids in silos, hoppers, and containers in the following industries: food & beverage, pharmaceuticals, chemicals, cement production, power generation, and woodworking. They are ideal for explosive atmospheres (ATEX), extreme temperatures and pressures, heavy/sticky materials, and hard-to-reach measurement points (tall silos, filling streams).

Advantages of MOLOSroto DF Rotary Level Indicators

• Reliability: Resistant to pressure, temperature, dust, adhesion, and conductivity; minimal risk of failure

• Versatility: Adaptable to various materials and conditions; ATEX gas/dust certification; long shafts/ropes for flexible installation

• Simplicity: Easy installation in any position; maintenance-free and wear-resistant; fast response

• Cost-effectiveness: Excellent price-performance ratio; compact design; reliable protection against overfilling and material run-out