How CROHMIQ works

How CROHMIQ® works

CROHMIQ® static protective fabric for Type D FIBC is designed and engineered to operate safely in the presence of flammable or explosive atmospheres without the need for a ground connection.

FIBC: Corona Discharge from CROHMIQ Type D Static Dissipative Bulk Bag

CROHMIQ® static protective FIBC fabric provides protection from hazardous electrostatic discharges by safely dissipating charge into the atmosphere by a process called corona.

Corona is one form of electrostatic discharge, but unlike sparks or brush discharges, corona is low energy and is not incendiary to flammable or explosive atmospheres.

Electrostatic Corona Discharge from Quasi-Conductive Yarn 
Low energy corona discharge
surrounding a circular conductor.

In CROHMIQ static protective FIBC fabric, corona is produced by patented quasi-conductive yarns that are interwoven with polypropylene tapes at intervals of about 20 mm (0.8 inch). The purpose of the quasi-conductive yarns is to concentrate the electric field from any charge that accumulates when filling or emptying an FIBC.

Electrostatic Corona Discharge: Field Strength from Quasi-Conductive Yarn

In the high field strength region (>3MV/m) air is split into electrons and positive ions. This region of ionisation quickly decays as the field strength falls off away from the quasi-conductive yarn. Ions produced in the air next to the quasi-conductive yarn are available to interact with any charge on the FIBC. Charge of the same polarity as that on the FIBC is repelled safely into the atmosphere, whilst charge of the opposite polarity combines with and neutralises charge on the FIBC. The net effect is that charge is dissipated safely from the FIBC into the atmosphere.

The advantage of using corona to safely dissipate charge is that it does not require a ground connection. Type C FIBC do require a ground connection because they rely on conduction to transport charge to ground; take away the ground connection and charge has nowhere to go. With corona, there is always somewhere for charge to be safely dissipated.

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