Dueldor Posted June 1, 2023 Share Posted June 1, 2023 Hello, my fellow metal heads! Got an idea I've been bashing around for about a year and a half. I am thinking of using an auto changeover to run two lpg cylinders for my forge. One empties the valve auto switches to the other allowing you to change and recharge without ever loosing pressure. Has anyone else run a setup like this? Do the auto changeovers work? I see a lot of them are output regulated to 11" W.C. which is not even .5 psi. Does anyone have a better way I can set this up than an autochangover? Thanks folks! Dueldor Quote Link to comment Share on other sites More sharing options...
Latticino Posted June 1, 2023 Share Posted June 1, 2023 Most folks who run dual cylinders simply run them both manifolded in parallel, drawing them both down simultaneously. You still have essentially the same overall working time as in your staged configuration, but the relatively lower draw per tank leads to less chance for freeze up. It doesn't help all that much for the recharge cycle, but most of us are not running a production shop where a short break to refill a tank is a significant issue. Actually if I had a productions hop I would just run parallel tanks and have one (or two) extra full one/s as standby for a quick switch. With experience you should be able to switch out a tank in a couple of minutes, and if running multiples in parallel you could still keep your forge running during that. Quote Link to comment Share on other sites More sharing options...
Dueldor Posted June 1, 2023 Author Share Posted June 1, 2023 Do propane level sensors work well in this setup? I'm just trying to eliminate the chances of mid project and all of a sudden I have no heat. I got a smokin deal on 2 100gallon tanks for $100 total. I wanted 40s, but that was less than I would have paid for 1 40 so I jumped! That and I tend to overcomplicate things to make them simpler lol. Cause that makes sense right? Quote Link to comment Share on other sites More sharing options...
Latticino Posted June 1, 2023 Share Posted June 1, 2023 Feel free to "Rube Goldberg" up anything you want, of course . If it were me I would just keep the second tank filled up as a standby and if the first one ran dry swap the tanks manually. Again this shouldn't take more than a couple of minutes. A 100 gal tank should last you quite a bit of time forging, assuming you have a decently efficient forge. If I had a more critical operation where I couldn't tolerate a 5 minute interruption in gas flow I would either directly pipe natural gas (as coincidentally I currently do - though not for continuity of service, just laziness) or manifold the two tanks in parallel with manual 1/4 turn ball valves to quickly switch over. The problem with overcomplicating things is that you give yourself more potential points of failure. For balcksmithing my watchwords are more often "robust and reliable". Quote Link to comment Share on other sites More sharing options...
George N. M. Posted June 1, 2023 Share Posted June 1, 2023 Latticino, I have seen any number of discussions about propane vs. natural gas as a forge fuel. Many of them hinge on the fact that domestic natural gas is supplied at a fairly low pressure which many commentors seem to think is too low for use in a forge. How is natural gas working for you and do you have domestic or industrial service (which, IIRC< is provided at a higher pressure than domestic)? I doubt that I would ever want to switch from propane since getting antural gas to my shop would involve 100'+ of trenching and piping in the shop but your experience and thoughts may be valuabl for others. Thanks, George Quote Link to comment Share on other sites More sharing options...
Latticino Posted June 1, 2023 Share Posted June 1, 2023 Mine is domestic pressure, and quite low. It wouldn't work in a NA forge, but I have a blown burner. The 75' buried gas line from my house is 1 1/2" diameter and the connection to the mixer is 1". My forge gets plenty hot. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted June 1, 2023 Share Posted June 1, 2023 2 hours ago, Dueldor said: Do propane level sensors work well in this setup? In fact they are infamous for not working worth beans. However, the frost line is a simple way to tell whats what. If you want more accuracy; serious people simply weigh the cylinders, when full, and subtract volume in accordance to weight reduction. Quote Link to comment Share on other sites More sharing options...
Frosty Posted June 1, 2023 Share Posted June 1, 2023 did you actually get two 100 GALLON tanks for $100 for the score of the week?! Or are they 100 lb. tanks? I can run two 3/4" burners for at least 16 hours on one. I fill them where they weigh the fill and do NOT crank the tank valve off hard. Don't let them drank them shut HARD, it damages the seats in the valve and then you have to reef on them or they leak and before long they leak anyway. Lots of 20 lb tanks are scrapped because they leak for this reason, look in the back lot at the propane outlet. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
George N. M. Posted June 1, 2023 Share Posted June 1, 2023 Latticino, OK, I would say now that the accepted wisdom is that natural gas at domestic pressure will work as a fuel with a blown forge but not with a naturally aspirated one. Since my propane forge is a modified Sandia model I will probably continue using propane in 30# tanks and my solid fuel forges. Thanks for the info. G. Quote Link to comment Share on other sites More sharing options...
JHCC Posted June 3, 2023 Share Posted June 3, 2023 On 6/1/2023 at 4:17 PM, Latticino said: My forge gets plenty hot. I can vouch for this. Quote Link to comment Share on other sites More sharing options...
Dueldor Posted June 8, 2023 Author Share Posted June 8, 2023 On 6/1/2023 at 3:49 PM, Frosty said: did you actually get two 100 GALLON tanks for $100 for the score of the week?! Or are they 100 lb. tanks? I can run two 3/4" burners for at least 16 hours on one. I fill them where they weigh the fill and do NOT crank the tank valve off hard. Don't let them drank them shut HARD, it damages the seats in the valve and then you have to reef on them or they leak and before long they leak anyway. Lots of 20 lb tanks are scrapped because they leak for this reason, look in the back lot at the propane outlet. Frosty The Lucky. Sorry, 100# tanks not gallon. Thanks for catching that frosty. Still less than what I would have paid for one brand new 40#. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted June 8, 2023 Share Posted June 8, 2023 IMO an auto switch system would not be worth the hassle/headache. Although unnecessary, my setup has a gauge for the tank pressure as well as one for the burner feed pressure. When I notice the tank pressure dropping down below 50 psi I have about 20 minutes left before needing to switch tanks. Typically I can swap tanks and start up again while the forge is still glowing and will ignite the propane just by turning it back on. Your mileage may vary. I'm a keep it simple kind of guy, so adding other things that can go wrong but don't significantly improve functionality (in my opinion) is a step backwards. You do you though. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted June 8, 2023 Share Posted June 8, 2023 Good stuff to know, Buzzkill Quote Link to comment Share on other sites More sharing options...
Dueldor Posted June 9, 2023 Author Share Posted June 9, 2023 Thanks for that buzzkill. I think I'll just do a manual valve to switch with a gauge after the valve so I can see what either tank has. Is there an advantage to having a gauge after the needle valve? Or is it enough just to have the one gauge? Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted June 9, 2023 Share Posted June 9, 2023 16 hours ago, Dueldor said: Is there an advantage to having a gauge after the needle valve? No, because needle valves affect flow; not pressure. Quote Link to comment Share on other sites More sharing options...
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