Awards & Engraving

2018 Laser Engraving Report

Issue link: https://nbm.uberflip.com/i/1036112

Contents of this Issue

Navigation

Page 9 of 32

LER 2018 n 9 The blue and green fan curves represent the fan performance of two different bathroom fans typically available at hardware stores. The red curve represents the restriction caused by a typical setup with 30 feet of ducting, four 90-degree bends, and a 24-by- 18-inch laser. The resultant airflow for each of the fans is deter- mined by where the red curve intersects the blue and green curves. So, the blue fan is predicted to deliver 60 CFM while the green fan is predicted to deliver 115 CFM. That's low for a vent-to- outdoor setup. The graph shows that the minimum duct velocity is not being met because the intersecting curves fall within the yellow area. The minimum duct velocity is the minimum air speed within the duct that ensures dust particles and aggregates won't excessively fall and accumulate within the duct due to gravity and cause hazardous blockages over time. In this example, it's quite clear that bathroom ventilation fans are unsafe and unreliable based on performance and best practices. This illustrates how a DIY idea might seem like a good one intuitively, but when techni- cally reviewed, it ends up being a liability. A blower would be more appropriate, but the selected blower still needs to be one that is designed to operate with contaminant- laden air. The blower needs to be a sealed type. This ensures that the contaminants do not leak out of the blower and back into room, which would defeat the purpose. It also needs to be the type of blower that can handle an accumulation of dust on its moving parts and can handle larger debris such as scrap bits of material that may fall down from the work piece and get sucked into the blower. An example of an appropriate blower is one with an open radial blade with back plate wheel. This type of blower is resilient to dust and debris while providing adequate pressure to overcome the duct and laser restrictions to achieve the specified venting airflow. Common blower wheel types include the forward curved multivane blower wheel and the backward curved blower wheel. Though the backward curved blower wheel typically has the pressure capability to overcome restriction in lengthy ducting, both types are not designed to operate with contaminant-laden air. They are designed for "clean side" applications where they are protected by filters. The same blower selection process applies to a DIY recir- culating fume extractor, except that you have to factor in the DIY fume extraction setup using bathroom ventilation fans. As noted in the text, this illustrates how a DIY idea might seem like a good one intuitively, but when technically reviewed, it ends up being a liability. Providing the key ingredient for a healthy and productive work environment: clean air. 1-877-9-QUATRO quatroair.com AIR TECHNOLOGIES INC. OVER 25 YEARS OF EXPERIENCE IN FUME EXTRACTION AND AIR FILTRATION Laser Fume Extractors For Any Setup And Budget, Big Or Small Daily eNewsletters Weekly Products & Deals Published Monthly Shows Across America Subscribe at a-e-mag.com/magsubscribe or call 800.870.0904 The Issue And More

Articles in this issue

Links on this page

view archives of Awards & Engraving - 2018 Laser Engraving Report