Sulfur Protection

Many industrial environments have invisible airborne substances that can damage electronic equipment.  Dust and moisture in the air are common enemies of electronic circuits.  There are other less common substances that are found in specific industrial environments that can be even more damaging.

Sulfur is one of those substances.  Airborne sulfur uses moisture in the air and is corrosive to the copper and silver commonly found in the conductive traces on circuit boards, in LCD circuits and resistive touch screens.  All of these components are found in the construction of an industrial lcd monitor.

http://www.chavant.com/new_site/files/pdf/HP_ImAg_Corrosion_Paper_ISTFA_20061.pdf

http://www.dfrsolutions.com/uploads/publications/2007_08_creep_corrosion_on_lead-free_pcb_in_high_sulfur_environments.pdf

A typical industrial monitor or industrial touch screen is not designed to resist the damage that can be caused by sulfur in the environment.  Without protection, most resistive touch screens will fail in as little as one year.  Most LCD circuits will begin to breakdown in less than two years causing non-responsive thin vertical lines in the picture.  Since most industrial monitors only come with a one year warranty, there will be no help coming from the manufacturer when these failures occur.

There are steps that can be taken to prevent the damage that is caused by sulfur to an industrial monitor.  These steps all fall under the category of creating a sufficient barrier between the sulfur in the air and the conductive circuits that exist in the components of the industrial monitor.  All of these steps increase the cost of the product in materials and labor.  However, the benefits far outweigh the cost.  The proper protection can extend the life of the industrial monitor out to the point where it will not fail due to sulfur damage.

There are three sulfur barriers provided on a Hope Industrial Systems’ monitor that has been purchased with sulfur protection:

  1. The resistive touch screen is protected on the front with a cover sheet that will not allow sulfur to pass through.  Typical touch screen design does not prevent sulfur from passing through the typical gas permeable cover sheet.
  2. The resistive touch screen is potted in a sulfur resistant barrier that prevents sulfur from contacting circuits from the rear of the touch screen.  This barrier is carefully chosen to be able to resist the low molecular size of sulfur.
  3. VCI Emitters

    VCI (Vapor Corrosion Inhibitor) Emitters

  4. A vapor corrosion inhibitor is sprayed on the conductive circuits and an emitter is provided with the product to create a lasting barrier.  VCI Emitters are devices that contain special compounds called Vapor Corrosion Inhibitors.  Emitters are used to protect enclosed metal components from corrosion by placing one or more of the devices in a container, package, or other enclosure.  The chemicals that vaporize into an enclosure are usually a blend of several special compounds that form a very thin layer (only a few molecules thick) on the surface as they interact with all metals present. These chemicals are unique in that they prevent the interaction of air and water moisture with the metal, thus preventing corrosion.

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