MOLOSmembran MF Membrane Level Indicators

MOLOSmembran MF is a series of membrane level switches from Mollet designed for reliable point-level detection of bulk solids in silos, hoppers, and containers. They operate completely without external power supply and have no protruding sensor parts inside the vessel. The series detects “full” or “empty” states and is suitable for coarse-grained materials up to 30 mm particle size. Available versions include MFA (small containers), MFB (coarse materials), MFD (pressure compensation via double membrane), MFE (universal for granules), and MFE-A (ATEX gas+dust). All models offer simple installation, high reliability, and are maintenance-free.

Operating Principle

MOLOSmembran MF membrane level indicators work on a purely mechanical principle using membrane deformation, requiring no external power. The membrane, integrated into the mounting flange, is pressed inward by the bulk material. This movement actuates a microswitch, generating a potential-free signal contact. When the material falls away, the membrane returns to its original position due to its own elasticity, opening the contact again. The system is insensitive to conductivity, dust, or adhesion. Sensitivity is adjustable (20 g to 2000 g depending on model) and response is immediate.

General Characteristics by Type

MFA

• Materials: Housing – ABS (IP44); Membrane – NBR

• Certifications: None

• Temperature: Ambient –10…+60 °C; Process –10…+60 °C

• Membrane sensitivity: 20…60 g

• Other: No power supply required; Contact 2 A/250 V AC, potential-free changeover; Any mounting position; Maintenance-free; Ideal for small containers

MFB

• Materials: Housing – aluminium (IP65); Membrane – NBR/VITON/stainless steel; Mounting ring – aluminium/stainless steel

• Certifications: ATEX Ex II 1/2D IIIC (dust); Ex II 2G IIC + II 1/2D IIIC (gas+dust); Intrinsically safe version available

• Temperature: Ambient –20…+80 °C; Process up to +200 °C (stainless steel membrane, non-Ex)

• Membrane sensitivity: 100…500 g

• Other: No power supply required; Contact 4 A/250 V AC, potential-free; Any mounting position; Maintenance-free; For coarse-grained materials

MFD

• Materials: Housing – GFK (IP65); Membrane – NBR/VITON; Mounting ring – galvanized steel/stainless steel

• Certifications: None

• Temperature: Ambient –20…+60 °C; Process –20…+70 °C

• Special feature: Double membrane for pressure compensation

• Membrane sensitivity: 60…200 g

• Other: No power supply required; Contact 4 A/250 V AC, potential-free; Any mounting position; Maintenance-free; Suitable for grain sizes up to 30 mm

MFE

• Materials: Housing – GFK (IP65); Membrane – NBR/VITON/stainless steel; Mounting ring – galvanized steel/stainless steel

• Certifications: None

• Temperature: Ambient –20…+60 °C; Process –20…+60 °C

• Membrane sensitivity: 60…2000 g (adjustable)

• Other: No power supply required; Contact 4 A/250 V AC, potential-free; Mounting via 20 mm flange; Maintenance-free; Universal for granules up to 30 mm

MFE-A

• Materials: Housing – aluminium (IP66); Membrane – NBR/VITON/stainless steel; Mounting ring – galvanized steel/stainless steel

• Certifications: ATEX Ex II 1/2D IIIC (dust); Ex II 2G IIC + II 1/2D IIIC (gas+dust)

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

• Membrane sensitivity: 60…2000 g (adjustable)

• Other: No power supply required; Contact 4 A/250 V AC, potential-free (intrinsically safe version); Mounting via 20 mm flange; Maintenance-free; For explosive atmospheres

Main Application Areas

MOLOSmembran MF membrane level switches are used for monitoring bulk solids in silos, hoppers, and containers across industries such as food & beverage, pharmaceuticals, chemicals, cement, power generation, and woodworking. They are ideal for explosive atmospheres (ATEX), coarse or sticky materials, small vessels, locations with risk of clogging, and any application where protruding sensor parts must be avoided.

Advantages of MOLOSmembran MF Membrane Level Indicators

• Reliability: Completely insensitive to dust, adhesion, and conductivity; no wear; extremely robust

• Versatility: Adjustable sensitivity; versions for coarse materials up to 30 mm and ATEX gas+dust zones

• Simplicity: No external power supply; no maintenance; easy installation in any position; immediate response

• Cost-effectiveness: Excellent price/performance ratio; compact and robust design; reliable protection against overfilling and empty-run situations

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