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Monday, February 22, 2021

Protection during the loading and unloading operations of liquids and dry inert material

The GRDE-4200 electronic earthing system help to prevent fire and explosions in areas with hazardous levels of static electricity when trucks or trains load and unload liquids and dry materials.
 
Filling, dispensing, transporting and tipping materials into vehicles or containers generates static electricity simply through the movement of the material being processed or handled. 
The charge level is greater for poorly conductive solvents flowing through plastic pipes. Furthermore, a fast flow or large amounts of air bubbles flowing through the pipe can amplify the static electricity. 
The flammable charge can ignite if the vehicle is not adequately earthed. 
An earth connection between the tanker and the earth network of the plant is not enough to prevent sparks from being generated a number of safety measures must be adopted, which connect the two systems safely, guaranteeing the safety of people and the property. These systems are commonly referred to as “earthing systems” and function based on the principle of equipotential bonding of conductive and semi-conductive metal objects while loading or unloading potentially explosive products. 
 
In potentially explosive atmospheres, these phenomena occur while loading and/or unloading vehicles carrying flammable and explosive products. Hazardous environments that require an earthing system are, for example:
  • loading/unloading tanker bays,
  • jetties used for loading/unloading oil, methane or gas tankers
  • silos used to transfer liquid or solid products.
During the entire loading and unloading phase, the device checks that the equipotentiality of the earthing system is maintained by using the connection of an earthing clamp. 
In fact, the electronic system is equipped with a protection circuit that checks the resistance value and compares it to the set parameter and, if this value falls within the pre-set range, closes the electrical circuit between the two systems that are equipotential. Viceversa, it removes the operating consent from the loading pump and closes the loading valve.
 
 
 
The GRDE-4200 is composed by:
 
  • ‘Ex eb/tb’ Cortem enclosure, which contain the ATEX/IECEx certified grounding control logic LCZ- 4200
  • Cortem ‘Ex eb/ tb’ control and signal devices such as selectors and alert LED lights
  • one or two earthing clamps for the connection to tank trucks or other metallic parts
Available in aluminum or in black polyester resin with antistatic properties, the GRDE-4200 has reduced dimensions and weight (3 kg) and a wide ambient temperature ranging from -40° C to + 60° C. The grounding system is equipped with a yellow spiral cable that is 8 meters long when extended, practical and not bulky when not in use.