Redesigning Metal Spray Room (help needed)
Redesigning Metal Spray Room (help needed)
(OP)
Hi all,
I'm working on a project to redo a metal spraying room, in terms of its ventilation and removal of metal dust in the air. The room is used to spray heated metal dust onto shafts that have been worn. Previously another engineer set up 2 exhaust fans on the wall of the room connected to ducts going to the atmosphere. The engineer also installed a motor and exhaust unit in the roof of the room attached to a ducting material that sucked air immediately behind the lathe onto which the shaft would be placed.
At the moment nothing seems to be working how it should in the room because the room gets very hot quickly and the metal dust quickly builds up in the air in the room and doesn't seem to be getting extracted quickly enough.
So far the research I did led me to believe that I needed to find the required CFM of the room and what the exhaust fans were actually pulling. Unfortunately, I cannot find any CFM values anywhere for the fans, the only data I have for them are the voltage, current, rpm and actual diameter. I have calculated, however, the required CFM of the room based on its size and # of air changes (based on safety standards).
Can anyone help me on this? I have been going in circles with this one and I need to solve this problem soon at work...
Thanks in advance!
I'm working on a project to redo a metal spraying room, in terms of its ventilation and removal of metal dust in the air. The room is used to spray heated metal dust onto shafts that have been worn. Previously another engineer set up 2 exhaust fans on the wall of the room connected to ducts going to the atmosphere. The engineer also installed a motor and exhaust unit in the roof of the room attached to a ducting material that sucked air immediately behind the lathe onto which the shaft would be placed.
At the moment nothing seems to be working how it should in the room because the room gets very hot quickly and the metal dust quickly builds up in the air in the room and doesn't seem to be getting extracted quickly enough.
So far the research I did led me to believe that I needed to find the required CFM of the room and what the exhaust fans were actually pulling. Unfortunately, I cannot find any CFM values anywhere for the fans, the only data I have for them are the voltage, current, rpm and actual diameter. I have calculated, however, the required CFM of the room based on its size and # of air changes (based on safety standards).
Can anyone help me on this? I have been going in circles with this one and I need to solve this problem soon at work...
Thanks in advance!





RE: Redesigning Metal Spray Room (help needed)
If you have a make and model number with the diameter you can look up the manufacturers information, If not your best bet is to do a flow test of the fans you have. You may also find that metal dust has built up on the blades and made them inefficient.
You should note, if you redo this room, you may have to add dust collection equipment you do not currently have, depending on where you are in the world.
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Redesigning Metal Spray Room (help needed)
RE: Redesigning Metal Spray Room (help needed)
The fan on the duct in the roof? is that a centrifugal or is that also an axial flow fan?
Regarding purchasing flow measuring equipment. It may be cheaper to hire a test and balance firm to come in and measure the actual flow for you.
Whilst not advising you what to do because I do not have enough information to make that call, I would suggest that for point of operation fume and heat removal you look at welding fume removal fans from companies like Plymovent.
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Redesigning Metal Spray Room (help needed)
You can also fax the fan manufacturers for their data sheets on the two fans and these sheets should have fan performance curve or tabulated data. Don't be surprised if you'll need a better exhaust system in order to cope with the pressure drop thru thedust collection system.
The extractor efficiency could be compromised if the make up air openings are insufficient in size.
RE: Redesigning Metal Spray Room (help needed)
I would warn against welding fume extractors for metal spray as the dust loading on the filter system is too great for most welding extractors.
There are a couple of reputable companies who are very familiar with metal spray applications. Suggest you contact Camfil-Farr and/or Donaldson-Torit - both very familiar in this field. Not cheap, but effective and safe.