Membrane level indicator to be used to control normally the medium or minimum level of bulk solids in silos or vessels. The models are certificated for use in potentially explosive Dust and Gas atmospheres as well as in hybride mixtures (Dust + Gas) hazardous areas.

These controllers consist of a switch actuated by a membrane and it is recommended for dusty and powdery, granulated and grainy bulk goods like dust, flour, grain, sand, plastic, etc. with an easy flow and a bulk density from 0.3 to 2.5 t/m3.

The membrane must to be exposed to the material.

The movement of the switch is the result of the pressure exerted by the incoming bulk material against the membrane which forces the membrane to move backwards, reversing the position of the switch and the signal is used for example to control the transport system in the silo.

The models have a regulation system by a spring that allows the adjusment of the sensitivity. Tightening the regulation nut to reduce the sensitivity and increase the strain of the material to activate the microswitch. Clockwise insensitive.

The models are adjusted at their maximum sensitivity. It is necessary to ensure the proper pressure to the membrane that returns the membrane when there is no product covering it.

Drill holes in the silo or vessel and mount the indicator using screws, rods, fasteners or nuts M6 making sure of the easy flow of the material and ensure that the product leaves the membrane without product on it.


Approximate measures given in mm.

Technical data

NameMembrane level indicator
TypePD-II-B3 – ref: 2205-A-002
PD-AII-B1 – ref: 2205-A-006
PD-AII-B5 – ref: 2205-A-004
B1 DustATEX II 1/2D Ex ta/tb IIIC T83° C
B3 DustATEX II 1/3D Ex ta/tc IIIC T63° C
B5 Gas+DustATEX II 2G Ex ib IIC T6
II 1/2D Ex ta/tb IIIC T83° C
Density of the product0,3 t/m3 – 2,5 t/m3
Ambient pressureAtmospherical
Maximum pressure+1 bar
Cable entryM20x1,5
Maximum voltage250 V AC
Contact function1 NO + 1 NC
Capacity of the contact:
PD (B1 and B3)15 A / 250 V AC (for resistive loads)
For inductive or capacitive loads reduce at 50%
PD (B5)Uo < 30 V DC; Ii < 100 mA
Ambient temperature:
PD-20° C – +60° C
PD (B1 and B5)-25° C – +80° C
ProtectionIP65 according DIN EN60529
PD: IP65
PD (B1 and B5): IP66
WeightPD: 0,49 Kg
PD (B1 and B5): 1,00 Kg
Sensitivity150 – 2.000 g adjustable
(Depending of the model. Consult your application to our Technical Department)
HousingPD (B3): Glass reinforced Polyester
PD (B1 and B5): Aluminum
MembraneStainless Steel 1.4301
Mounting ring and screwsStainless Steel 1.4301
Cable glandPD (B3): Polyamide
PD (B1 and B5): Niquel-plated Brass

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