Greenheck - Laboratory Exhaust Fan Nozzle Types Demonstration скачать в хорошем качестве

Greenheck - Laboratory Exhaust Fan Nozzle Types Demonstration

Click here to check out the PDF for more information: https://content.greenheck.com/public/... Transcript: Greenheck. Building value in air. Welcome to Greenheck’s Virtual Lab. There are three primary nozzle types that are used for pre-engineered laboratory exhaust systems. The first is called a High Plume Dilution Nozzle and Wind Band. The nozzle sits on top of the fan whether it's an inline fan or a centrifugal. With a high plume dilution nozzle you'll generally see nozzle velocities in the range of 4,000 to 7,000 feet-per-minute. Because what this nozzle is designed to do, is take outside air to mix with your laboratory air, and dilute what's coming out of the top of the product. So this is a perfect solution when your fan is adjacent to an air intake. Now the disadvantage of this style of nozzle is to create such high nozzle velocities can create sound. It also creates more back pressure because of these higher velocities. And you have to be careful that you're not driving your horsepower levels too high. The alternative to a High Plume Dilution is simply a High Plume Nozzle. In this case there is no dilution aspect so whatever comes through the fan comes out in equal volume through the top of that that nozzle. What I find with the high plume nozzle is that I can get equal or better plume rise but since I have lower nozzle velocity, you know generally up to 4,000 feet-per-minute, it creates less sound and there's less power to get that plume to a higher level. And in general, it's a little bit less expensive as well, so it reduces the upfront capital cost. The final nozzle style is called a Variable Geometry Nozzle. With a variable geometry nozzle, allows the nozzle area to change in-flight to maintain a consistent nozzle velocity. So as there are changes in your system, for example a sash closes and the fan speed can slow down based on the new demand, these blades can change in-flight to maintain a constant nozzle velocity. This is a great way to reduce the cost of operation of your lab while still maintaining a high overall plume rise.