Deflector Hoods & Bleeds

Every good performing extraction system starts with a well-designed extraction hood. Effective hood design can make all the difference between a mediocre, a good and an excellent extraction system. JOA extraction systems are able to reach up to a 95% extraction efficiency.

There are as many hood designs as there are applications. A hood can be outfitted with slots to prevent over-extraction of air and to make the system more energy efficient. Every part of the hood is shaped to optimally accommodate air into the system.

In many situations, a simple extraction system will suffice, but in others a push-pull system is advisory. In a push-pull system, air is not only extracted, but a current of clean air is used to push the polluted air towards the extraction hood. This ensures a more precise and efficient method of extraction. In addition, the current of fresh air is beneficial to operator health and safety.

The piping needs to meet the same strenuous requirements as the hood. Every bend and curve is designed to maintain an optimal air current between hood and collection. On a brand new system, JOA favors the use of piping without valves. Any element that can disturb the airflow, like valves, can cause a buildup of particles within the system. This buildup can, depending on the type of particle extracted, cause anything between maintenance downtime and serious explosion risk.

Optimizing Hoods with advanced Computational Fluid Dynamics

CFD-optimized extraction systems and deflector hoods are designed to minimize the extraction of valuable dust. This also reduces the risk with explosive dust in the ATEX zone and reduces the downtime of the facility due to lesser need for cleaning or filter replacement.

The JOA Deflector Hood™ in combination with our GCM™ Air Technical Modeling software guarantees an atmospheric (pressure less, -1Pa) extraction on sensitive process equipment, such as feeding equipment. This means the following:

• Product Recovery: Product particles are mainly recaptured back in the process, having only a minor amount of dust ending up in the filter.
• Reduces Risk of Pressure Build-up: The risk for pressure build-up or backflow during feeding processes are eliminated due to balanced (atmospheric) venting. This prevents influences at the weighing and feeding.

Applying the JOA Deflector in combination with a balanced extraction system, including Balancing Restrictors can lead to:

• Less decline of product, rejected batches and improved product quality.
• Eliminating cross contamination
• Precise dosing / feeding made possible
• Reduced dust emissions at the emission source
• Reduced material / powder waste (40-70%)
• Less maintenance required
• Guaranteed ‘Maximum Allowable Concentration’ (MAC) resulting in operator protection ( e.g. g.< 1mg/)