{{image4-a:r-w:200}}A dust-tight valve can help you mitigate these potential effects simply by the way it is designed. It is important to select a valve specifically designed for dry/bulk processes, as dust will always migrate through the path of least resistance. This can be a challenge when using soft polymers and packing as seals. Many dust-tight valves designed today feature hard polymers (eg nylon, PET) as a sealing surface, because they tend to offer better wear characteristics for most applications.
Safety, environmental requirements
Dust control has been given a higher priority in materials processing over the past few decades. Fugitive emissions from a valve into the atmosphere can be detrimental to the environment and a potential safety hazard, with airborne particles forming a significant hazard in the mining and quarrying industry.
As well as being a general nuisance, excessive dust can affect the health and safety of workers by causing visibility problems, and result in eye and lung issues.
Dust-tight valves are often required in processing facilities, as they can drastically reduce the percentage of fugitive dust.
However, when replacing a regular valve with a dust-tight valve, it is important to verify that the connections between the valve and what sits above and below are tight. For example, transition flanges need to be true and flat, with no bow, and gaskets need to be inspected and replaced if necessary. Keeping a good seal on every connection, minimising the escape of dust from your process equipment, and inspecting and cleaning dust residues at regular intervals are all part of a robust dust control safety plan.
The seal’s polymer material will eventually wear down and the valve will need to be resealed. To minimise maintenance costs, select valves that offer cleaning and maintenance friendly features. Some manufacturers design valves with small slots in the body that let material slowly leak, as an indicator that the valve needs maintenance. Operators should also choose a valve designed to allow routine inspection without removing it from the production line. Convenient side access doors should then allow you to replace the old seals with new ones and start production back in minutes. In comparison, valves featuring rope require more downtime, as the cartridge needs to be pulled out of the valve to remove the old rope and install a new one.
Eventually the valve will have to be taken out of service for seal replacement. That is why it is important to select the right valve and seal materials for your specific application. The correct choice of materials will extend the valve’s service life by compensating for wear and tear, and provide an excellent material seal across the valve. The ingredients being processed will also dictate your valve and seal contact materials. Cast iron, carbon steel and aluminium are common valve materials for many bulk applications, but more corrosive or abrasive materials require more durable alloy coatings such as hard polymer, stainless steel or carbide for the material contact points to guarantee a long service life.
Plant profitability
Dust-tight valves are initially more expensive than other valves and require higher initial capital equipment expenditure. However, dust-tight valves tend to make up for the original cost difference in the long run in several ways. By keeping a tight seal, they limit the risk of material cross-contamination and increase final product quality. Their dust-tight design drastically reduces material leakage in the plant and the atmosphere and directly affects a plant’s bottom line, as it reduces concerns about product waste and pollution. Finally, dust-tight valves are easier to maintain and service. Many don’t require a production line shutdown longer than a few minutes at a time.
Selecting the right valve
When it comes to selecting the right valve for your dry process application, there are many slide gates and diverter valves to choose from. Process valves are used to control the material flow in bulk material handling systems. They can be used in gravity flow or low-pressure systems, as well as negative pressure systems, with each system calling for different equipment requirements.
Overall, choosing dust-tight valves for your dry bulk applications will limit maintenance costs, reduce safety and environmental hazards, and reduce downtime. With so many valve options available, it is best to go with a company that has years of application experience and can help you pick the right valve for your specific powder/bulk process.
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Many parameters have to be taken into consideration when purchasing a valve, including the type of material being processed, if the material is abrasive or corrosive, the particle size and temperature, and if the material is being conveyed by gravity, vacuum or pressure. Many dust-tight valves can be custom-designed to meet exact application needs, and these will often provide the best results.
Distributors
Vortex Valves are designed specifically for abrasive material, identifying slide gates and diverter valves’ key wear points, reinforcing those areas with abrasion-resistant materials, and adding features to reduce the time it takes to perform maintenance on the components. These improvements extend the valve’s service life and reduce life-cycle costs.
Vortex has engineered slide gates, diverter valves, iris valves and loadout equipment for a global network of manufacturers, OEMs and Fortune 500 companies for more than 35 years, and earned its reputation as a specialist in valves for handling dry bulk solids.
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Brolton Group is the exclusive agent for Vortex Valves in Australia. It works with members of the heavy industry, FMCG and broader manufacturing sectors, providing breakdown support to award-winning, turnkey factories noted for design excellence. Brolton is ISO 9001:2008 Quality Management certified, demonstrating its dedication to world-class engineering solutions and unrivalled customer service.
Source: Brolton Group/Vortex Valves