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PROPER DUST COLLECTION: THE RIGHT WAY TO MINIMISE THERMAL SPRAY HAZARDS

by Major Welding ∙ Mar 21st, 2017

Every time powder spraying is executed, minute dust particles from a variety of different metals enter your bodies and cause major health risks. All thermal spray released contaminants threaten workers’ health and safety.

Before finding a head-on solution for the problem, let us first take a step back to understand the thermal spray process itself! It is an industrial coating process that melts coating material in either dust form or wire form. These materials are then passed through a flame, and then the tiny droplets that are formed are coated on surfaces in a high velocity. Now, the excess dust particles pose a major threat to health.

The dust particles contain different metals that harm your body in different ways. The entry point for these harmful particles is through the respiratory system. They also enter through the eyes, skin or ingestion. You can take a closer look at the particulate matter by going through Material Safety Data Sheets. These metals occurring in your process need to be identified for a strategic safety measure. It is also important to adhere to permissible exposure limits established by OSHA.

Nickel is the most common allergen in these cases, and it is classified by the National Institute of Occupational Safety and Health as a potential occupational carcinogen. It is alsorecognised as a carcinogen on the Program list of National Agency for Research on Cancer and Toxicology. Beware if you or any of your workers feel nauseous, experience a metallic taste, fever, allergic reactions or tightening in the chest area. Long-term exposure to nickel dust can cause chronic illness like pneumoconiosis and lung fibrosis.

The second dangerous contaminant is Cobalt. Over exposure to copper can lead to diseases like contact eczema, dermatitis, respiratory irritation, decreased pulmonary function and diffuse nodular fibrosis.

The next dangerous particulate matter is copper. Copper is responsible for irritation in eyes along with the occurrence of cough and dyspnea (dysponea).
The best way to deal with these health threats is to regulate a dust collection system that is specifically engineered for your particular thermal spray action.


DESIGN CONSIDERATIONS FOR POWDER AND DUST CONTROL

The proper dust collection system can control powder and dust. Nevertheless, a few issues are more particularly related to booth structure and controls. The booth design should be linked with good ventilation flow and control. The design can have a big effect on the ability to create good ventilation flow and conduct spray waste powder to the filtration system. So, it is necessary to gauge each process and the result of the process intended for the spray action when it comes to designing an exhaust system.


PICKING OUT THE RIGHT FILTRATION

Filtration is a vital cog in a properly working dust collection system. Consider the below-listed factors that influence filtration performance:


AIR TO CLOTH A/C RATIO

  • Conservative A/C ratios are suggested for cartridge dust collectors in thermal spray operations.
  • Nanofiber filter media fuse high performance with long life.


PREFILTRATION MODULES

These can be employed in addition to dry media filters to improve cleaning efficiency by allowing the capture of huge amounts of dust carried in the airstream prior to reaching the primary dust collector.


SECONDARY FILTER SYSTEMS

Call it an after filter or final filter, secondary filter systems are suggested for use downstream of the primary filtration system.


SAFETY MONITORING FILTERS

These filters use high-efficiency particulate air (HEPA) filters to improve the dust capture efficiency of dry systems and give backup protection in case there is an air leak through the primary filters.

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EXPLOSION PROTECTION COMPONENTS

The incorrect mix of dust particles and thermal sources can lead to explosion. Thus, it’s essential that the dust collection system has the correct gears to thwart this danger.

Explosion vents are compulsory for all thermal spray processes. These vents direct the internal pressures of an explosion in the dust collection system away from personnel and equipment.

Now that you know the causes and effects of particulate matter, the design considerations and the right filter knowledge, you and your workers have a better chance to seek protection from such harmful agents. Fight the diseases at the core; not just by prevention but also by informed and smart design and filtration options.