Ice Czar Posted December 12, 2008 Share Posted December 12, 2008 (edited) A compressor is an inefficient and costly way to run a forge. most compressors but not all compressors are an inefficient and costly way to run a forgeprobably the oldest dedicated compressor for a forge http://www.motherearthnews.com/Renewable-Energy/1977-07-01/Harness-Hydro-Power-with-a-Trompe.aspx Edited December 12, 2008 by Ice Czar Quote Link to comment Share on other sites More sharing options...
ironrosefarms Posted December 12, 2008 Share Posted December 12, 2008 (edited) The production plant I work at uses a good deal of compressed air and vacuum operated equipment. We have two 50hp screw compressors, we run one at a time 24/7 use the other as a back up. Very expensive units, however very efficient. As for maintenance the parts are expensive but they are fairly easy to work on, second the maintenance is done on a 6 month rotation and costs about $1000 each time. Our budget is $4000 for maintenance on these units. Remember there is one running 24/7. We only use about 1/2 of the available air from one unit, we never bog them down and our air usage is incredible. As I sit here no machine is running, the only sound is constant air loss from the idle machinery. Our screw compressors use no storage tank, it is on demand... It isn't like the compressor I have at home that is constantly trying to keep up with filling a tank by moving a couple pistons up and down. Another note they are quite noisy, ours sit in their own room their only neighbor are the two very large vacuum pumps (very noisy and inefficient), not a room you would want to sneak away in for a nap! If I had the chance to build a forge here at work, compressed air would be my air source... at home a blower will do very nicely thank you. Edited December 12, 2008 by ironrosefarms Quote Link to comment Share on other sites More sharing options...
Vili Posted March 11, 2009 Share Posted March 11, 2009 Hey Folks.i once had a job forging the "teeth" for walnut cracking machines,Dragons,and I had to set-up a forge useing compressed air. Here's how i did it. I took two 1/4 turn gate valves and conected them inline to the standard brake drum forge. When it was connected to the air supply I simply started with the valve closest to the forge(#1) open all the way and the other one(#2) closed. Open #2 slowly until you are getting the strongest blast that you want and mark or lock it there. Use #1 to very the air slower and to stop the air. Hope this helps, Vili Quote Link to comment Share on other sites More sharing options...
element Posted March 11, 2009 Share Posted March 11, 2009 Ironrose, What do you guys fabricate? Im just curious. Quote Link to comment Share on other sites More sharing options...
merl Posted March 12, 2009 Share Posted March 12, 2009 There is "shop air " and then there is "plant air". Shop air seems to be what is usualy supplied by an under powerd piston compressor that is often purchased with the up front cost as the priority. It seems that no matter how big your piston compressor is, it will end up being too small at some point and that will keep happening more and more as your shop gets more ambitious. Plant air is something that is figured in to the cost of doing business, and should be part of your calculation for determining the shop rate ect... If you already have a compressed air system that has to run all the time anyway and, IF it has the capacity to run these additional air devices (what was said? 250-300 cu.ft./min. x up to 7 units) along with all the other air users in the plant. As Frosty suggests, the air indusers will do a good job in this situation and, depending on your shop layout, it may be the only safe alternitive to supplying air to all these forges, rather than individuale blowers. The shop were I work doesn't even allow radios and personal fans because of the inheirant danger of all the elctrical cords (electrical cords and sharp, black hot metal chips don't mix). Every machine has a line for an air blow gun and two more for air grinders ect... In a large plant, compressed air is the way to go. At home I use a Champ 400 on my coal forge. If I ever needed a compressor to run machines at home ie, an air powerd hammer, I would invest in a screw compressor and run a line to every building, as that would be the "tipping point" for me as far as effiecancy goes. Quote Link to comment Share on other sites More sharing options...
Warren Nakkela Posted March 12, 2009 Share Posted March 12, 2009 Look up "eductor". Warren Quote Link to comment Share on other sites More sharing options...
merl Posted March 13, 2009 Share Posted March 13, 2009 Yes Warren, I actualy use those in my fish farming operation. I generaly don't call them that because most people are not familier with that word. Quote Link to comment Share on other sites More sharing options...
anvillain Posted March 14, 2009 Share Posted March 14, 2009 Frosty, I would never have thought of using compressed air in that way. Now that you mentioned it I remember using a similiar device back in the 80's when working in the containment building of a nuclear power plant. An "air horn" is the only term I can come up with now, but there may have been another trade name used for it. It was an aluminum doughnut with about a 3" ID, and had approx. 3 ft long sheet metal funnel that opened up to maybe 8" dia. Plant air would be hooked up to the small end and was controlled by a ball valve. It had small orifices around the doughnut shooting air toward the large end. If one went into hot or smoky area you could blast it outta there very quickly then throttle it down to just a whisper for comfort and ventilation. Your idea would be on this same principle, but much smaller in size. Of course in a containment bldg. if you cleared your area you were really only diluting the pollution and sending it somwhere else. It was not conducive to good health in there. This is quite a departure from supplying air to a coal forge. Folks, forgive me for ruminating about past jobs. Old pipefitters tend to do that. OK back to the subject matter, The point is: a little bit of compressed air flowing through your injector picks up a whole lot of other air to go with it. It is such a clever device, and doesn't require a huge amount of compressed air. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 14, 2009 Share Posted March 14, 2009 Was the compressed air introduced through a slit going around the inside of the venturi? (donut shape) Sounds like what the few papers I have call an "air amplifier" another induction device with a much higher induction rate, on the order of 40:1. They're not at all usable for forge burners but would work very well for supplying forge air. One commercial use is for "air conveyors". They shoot a laminar flow of air down the inside skin of a pipe. This flow induces about 40X as much ambient air plus just about anything else small enough to fit in the pipe. These things will convey anything from coal to gravel to grain. The hot thing for milling grain was to fire it from one silo using however air amplifiers in the line as necessary to get it going the right speed and then slam it into a steel target. The grain is milled to whatever finish they want depending on speed and the resulting flour is carried off to another silo by more air amplifiers. It's a very slick system, from grain to flour and total transport and it never touches anything but the steel target. Frosty Quote Link to comment Share on other sites More sharing options...
anvillain Posted March 15, 2009 Share Posted March 15, 2009 The devices I've seen I am pretty sure did not have a slot. I think they had 4 small holes no more than an 1/8" dia. and they were probably operating around 100 psi give or take 20. Another place I've seen them in use was in refineries. There they could move huge volumes of air to get rid of volatile fumes without using any electricity. for safety. After looking at the previous post that mentions "eductor" it reminded me of what some guys called these. I think some referred to them as "ducks" I now can see the possible derivative, but it didn't make much sense to me at the time. Anvillain Quote Link to comment Share on other sites More sharing options...
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