Static Control for Safely Filling FIBC Bags

Exloc Instruments: your one-stop-shop for instruments and electrical equipment for use in hazardous classified locations.
Saving you time & money solving challenging problems!

Static Grounding for Type C FIBC "Big Bags"

Photo of Newson-Gale Earth Rite static control monitor for safe filling of Type C FIBC big bags

Photo of a typical FIBC bag filling machine protected by Newson-Gale Earth-Rite static control system

Earth-Rite FIBC

Insures correct grounding
Checks for bag integrity
Includes interlock control contact
Intrinsically safe
FM approved Cl I II III, Div 1, Grp A-G
ATEX certified
LED status indication
Self testing system
Suitable for other dissipative containers

The use of Flexible Intermediate Bulk Containers (FIBCs) has grown in line with the worldwide need to transport and store powdered, flaked and granulated products more efficiently and economically. Whilst this has resulted in huge increases in productivity, it has also brought with it additional safety issues which should be addressed by all responsible plant operators. One such issue concerns the dangerous build up of electrostatic charge during FIBC filling and discharging.

As the FIBC is filled there is a steady accumulation of static charge which, if left unchecked, may result in spark discharges from the surface of the FIBC, or charging of adjacent isolated conductors by induction. This may in turn provide sufficient energy for ignition of certain flammable vapours and dust in air concentrations, as well as being a potential source of a dangerous physiological shock.

In order to control this problem, many FIBC manufacturers offer Type C "anti-static" or "conductive" constructions, using either interwoven conductive threads or other static dissipative materials.The container is then earthed/grounded, typically using clamps attached to designated tags, enabling static charge to dissipate before it builds up to an excessive level.

However, even if a company has correctly specified Type C FIBCs, some uncertainties still remain:

Has the operator correctly fitted the clamp and "earthed" the FIBC?
In the case of a "multi-trip" FIBC, has the bag lost some of it's anti-static properties through damage or wear and tear?
Is the operator using the correct FIBC?

To address these issues, the Cenelectrex Earth-Rite FIBC system has been developed to enable users of Type C anti-static flexible intermediate bulk containers to check that the bag construction is within the correct specification and correctly earthed.

To suit various types of filling/discharging machinery the system is offered in two formats which monitor resistance either between the lifting loops and one earth clamp with respect to earth, or between two separate earth clamps with respect to earth. The system is FM approved intrinsically safe for use in all hazardous (classified) locations, and is also ATEX certified.

The Earth-Rite FIBC makes a valuable contribution to plant and personnel safety, helping eliminate dangerous accumulation of static charge which can result in fires/explosions within flammable atmospheres.

Schematic diagram of a Newson Gale Earth-Rite FIBC bag filling static control system

System Description

The system is set to engage the product transfer circuit only when the resistance through the container is within the range of 500 Ohms to 100 Meg Ohms. If customers are using specific FIBCs, or have their own safety standards alternative resistance ranges may be supplied to special order. Until these conditions are achieved, the system remains non-permissive. The resistance limits imposed by the system help personnel to observe correct and safe operating procedures.

The system utilises a special insulated monitoring clamp which should be attached to the conductive earth loop of the FIBC. This clamp is connected to a chemical and abrasion resistant Hytrel-coated spiral cable and forms the monitoring connection so that the resistance through the bag and down to earth can be monitored. The static dissipation path is provided by the lifting hooks which should be connected to ground.

If the lifting hooks cannot be used for grounding, the system verifies the resistance between the monitoring connection and an additional connection down to earth. The system also provides a visual indication of earth condition via red/green LEDs, and is designed to meet current EC directives.

You may also be interested in these related products:
multipoint static systems • road tanker loading • self testing static control • shoe testing stations

legal notice • site map