Archie Zietman Posted June 21, 2005 Share Posted June 21, 2005 Hello. I have decides that my pool toy-blower is not very good, and have decided to embark on the quest of making a very large bellows. I will probably make a single-chabered bellows, but how does one chamber them? is the flap-valve in any way different on the inside of the bellows? Basically, how does a multi-chambered bellows work? Thanks very much, Archie Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted June 21, 2005 Share Posted June 21, 2005 A one chambered bellows has a valve that shuts when you pump it and the air stops when you stop. A two lung style is basically two single chambered bellows attached to each other. Air enters the bottom chamber when you pump and eventually begins to fill the upper chamber. Both chambers have one way valves but air can only escape from the nozzle on the top chamber. You can pump #1 vigorously and the top one will pressurize and blow continuously so a steady stream of air is achieved. You can also use two single chamber bellows side by side and get a good blast. Our group built a concertina style for a Spanish mission forge that are two lungs which look like accordions feeding a common tuyere. You stand behind the forge and pump with both hands. Several guys here and on Anvilfire have built very good bellows and would probably be willing to share plans if you ask nicely. :wink: Quote Link to comment Share on other sites More sharing options...
Archie Zietman Posted June 21, 2005 Author Share Posted June 21, 2005 ok. ahem. If any of you chaps or chapesses has a pattern/plans for a bellows, may I please see them? Thanks, Archie Quote Link to comment Share on other sites More sharing options...
gerald Posted June 21, 2005 Share Posted June 21, 2005 Here's a site with good drawings/text of a set of double acting bellows:http://www.emainc.com/radnor/bellows.htm Also, Lindsay Publications sells a VERY detailed booklet entitled"How to Make a Blacksmith's Bellows" by Robert M. Heath. The book describes the disassembly, restoration and re-assembly of a bellows in a museum in Mississippi. It's the real deal and it's only 5 or 6 bucks. You might also do a Google search for forge bellows. You'll get a few hits including the site I listed above. Quote Link to comment Share on other sites More sharing options...
Archie Zietman Posted June 21, 2005 Author Share Posted June 21, 2005 Thanks! Quote Link to comment Share on other sites More sharing options...
Don A Posted June 21, 2005 Share Posted June 21, 2005 Archie, I am actually hoping to start the final assembly on a double-action bellows this evening. Mine is made of mostly salvaged material. I wanted to build a cheap set before I went and invested in good wood and leather. This set will be mostly ply-wood, except fot the top. I glued up some 6" pine flooring for the top. I plan to use canvas ($4 / yard) instead of leather ($$$). I believe I can paint & stain all the "moderns" and still make it look good enough for demos. It is now in 5 pieces, so I'll try to get some pictures of the parts and the final assembly. Still gotta install the valves then attach all the hinges. Then it should be ready to cover. Quote Link to comment Share on other sites More sharing options...
irnsrgn Posted June 21, 2005 Share Posted June 21, 2005 http://www.iforgeiron.com/Blueprints01/BP0127Bellows/BP0127.shtml Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted June 21, 2005 Share Posted June 21, 2005 If you are going to the trouble of making one, go at least 2' wide by 3' long and 3x4 would be better. That way, you can go to a standard firepot or side blast tuyere later and have plenty of air. Quote Link to comment Share on other sites More sharing options...
Archie Zietman Posted June 22, 2005 Author Share Posted June 22, 2005 this is the portable bellows design I have come up with correctly will it work? http://www.yourimg.com/?page=05/173/18/bellowshanging.jpg Quote Link to comment Share on other sites More sharing options...
Glenn Posted June 23, 2005 Share Posted June 23, 2005 Archie At rest, the bottom chamber is filled with air. When activated, this air is squeezed and pushed into the top chamber which starts flat and now has expanded with the air from the bottom chamber. The bottom chamber is opened to again to fill with air and the top chamber now, by gravity, pushes top chamber air into the fire. Repete as necessary. Flaps of leather, rubber etc. act as one way valves to keep air flowing toward the fire. These things have been in use for many years and work. Build an existing design first to see how and why things work and then you have a base line of knowledge to work from for further modifications. Or go in search for a small squirrel cage blower and be happy with all the air you can use, and no sore arm muscles. Big squirrel cage blowers work also, you just have to vent the excess air. Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted June 23, 2005 Share Posted June 23, 2005 Unless you are just interested in building the bellows for fun, I tend to agree with Glenn and recommend a little electric fan until you can find a real blower. A squirrel cage does not work quite as well as a centrifugal blower on mineral coal but charcoal is easier to push air thru so you'll get a good fire. However, don't be discouraged from building a bellows if you want - it will work quite well. Quote Link to comment Share on other sites More sharing options...
Woody Posted June 23, 2005 Share Posted June 23, 2005 I have plans for a two chamber bellows, built a set a year ago, they worked just fine. If you want the plans, email me and I will send them to you. The building of the bellows is also a blueprint on ifrogeiron.com Woody Quote Link to comment Share on other sites More sharing options...
Don A Posted June 23, 2005 Share Posted June 23, 2005 I like a man that draws it before he builds it... shows that your thinking. Two things I see in your drawing that I don't think are necessary. 1. - the stick to hold it level. Your bellows are normally going to be ridgidly attached to the forge pipe when in use, so it finds its own "level". 2. - the weight holder and weights. Sometimes a well made bellows doesn't need any extra weight. If it does, lay a piece of scap, a brick, or an extra hammer on top it. Neither of these things are bad; just more work. Have a look at this picture. It shows you that you really don't need to over-think the whole forge and bellows concept: http://www.army.mil/cmh-pg/LC/Explore/Circle_of_Cultures/Cultures0024.JPG Keep drawing; keep building. Quote Link to comment Share on other sites More sharing options...
Ralph Posted June 23, 2005 Share Posted June 23, 2005 I kike using a bellows. But then I am not looking at this on a commercial level. Then I have an electric Buffalo blower in teh shed too. FOr me the bellows allows me to become calm and centered. About the way soem folks feel about using a nice hand plane. Sure a sander might be faster, but is that thte real point? :?: Quote Link to comment Share on other sites More sharing options...
Archie Zietman Posted June 23, 2005 Author Share Posted June 23, 2005 I have the boards cut out for the bellows. It's made from 3/4 inch plywood of some sort, so it's VERY heavy, but that's what I had, so... :D Quote Link to comment Share on other sites More sharing options...
Don A Posted June 24, 2005 Share Posted June 24, 2005 OK, let's see if this works. Here's some shots of my progress so far. I hope to get everything tied together this weekend. Let me know if you have any questions. Quote Link to comment Share on other sites More sharing options...
irnsrgn Posted June 24, 2005 Share Posted June 24, 2005 Don, in the for what its worth dept. In my opinion the valve openings are way to small and the center section should have 2 valves the same as the bottom. Of course my bellows are larger 6 foot long by 3 feet wide at the widest, buy this is what I think will happen with such small openings; 1. The bottom section will be very slow on the recovery (the down stroke), as you are trying to replace a large volume of air by the suction process thru 2 very small openings, and the restriction will severly limit the time needed to refill the bottom section. And you must remember that the valves do not fully open so this limits the ability of the air to enter the chamber also. Kind of a general rule of thumb you can only expect half the volume of the hole size to move thru the hole due to the restrictions. 2. The top chamber valve openings will more or less be under pressure when the bottom chamber is closed forcing air into the top chamber and having only one valve opening will result in a slow rate of expansion and will require a lot more force on the handle to fill the top chamber and this factor will severly limit the amount of air you can get into the fire and thus limit the heat output of the fire. 3. The pipe extending into the the top chamber will creat a lot of friction (read restricted movement of air). A tapered chamber prior to entering the pipe will act like a venturi (read turbo charger) and cut the friction loss, thus increasing the amount of air entering the pipe. I have dual valves with 6 inch diameter openings on my bellows and at times when maintaining a large hot fire the recovery rate of the bottom chamber is slow. Just my observations from using my bellows, and guessing at what will happen with such small openings. Irnsrgn Quote Link to comment Share on other sites More sharing options...
Don A Posted June 24, 2005 Share Posted June 24, 2005 Irnsrgn, Thank you much for the input. I have made the valve bodies removable, so I am going to go ahead and give it a try as is, since I'm already this far in. I can't remember exactly where I picked the info up at, but I had copied this formula and saved it several months ago:On my big bellows I put two valves about 3" diameter in a seperate board on the bottom of the bellows. This was attached with brass screws and removable so that you could reach inside remove the middle board valve body which had only one valve and was a smaller board. The logic was like automobile valves, the intake was large due to the low pressure differential, the exhust (to the top) was smaller because it had mechanical pressure pushing it. The two 3" intakes and the one 3" exhust worked very well and had no discernable resistance. Removing the valves also gives you access to the inside for making repairs such as to the leather. BTW, this thing is only 3' x 4'. If it doesn't work to suit me, I'll drop those boards out and open everything up a couple inches. Also, I might go ahead and bob that pipe off flush and add some tapered blocks in beside it. This won't be as efficient as a cone, but it might help with the friction. Good call. Thanks again for the advice, Don Quote Link to comment Share on other sites More sharing options...
bruce wilcock Posted June 24, 2005 Share Posted June 24, 2005 there are a set of old snipe nosed bellows a the back of the shop i had given years back around 6 ft long and the valves are a lead weghted wood flap 9 ins long 8 ins wide covering a hole about 7 long 5 ins wide both valves are the same size the bellows were made by Alladays they made alot of blacksmiths eqipment ,so i think they will have thought the valving out, olso the valves have had a light leather strap to stop them going right over and jamming open,, the nose end is rotted of so no help there, thats all i can help Bruce Quote Link to comment Share on other sites More sharing options...
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