propane tank repeatedly "failing"

[KPeacock]

I've got my propane forge up and running and i am having a problem with my propane tank. there is some sort of a safety feature present that causes the pressure to drop to nearly zero anytime the flowrate exceeds some trip limit. I have my tank hooked to a hose that is then plumbed through a regulator, a pressure guage, an emergency shutoff globe valve, and then a 1/4" needle valve before endering my forced blower orifice.

 

Is there a way for me to keep the tank from shutting down? this is NOT the result of freezing up the tank, this is something entirely different.

 

Thanks for your input and help.

 

PS, the forge does get up to welding temperature. To test it, I made a half hearted attempt at chain damascus using chainsaw chain. I did not work the metal much. I simply hammered it flat and then hit it with the grinder to rough out the shape. you can very clearly see areas that did NOT weld well, but overall, it worked out better than I thought for my first attempt at it. It's got a pretty rugged look to it, thats for sure. I'll likely do some more filing and refine it a bit and then see about making a handle out of delran.

 

[tell]

i fitted one of those emergency cutoff valves and got the same results also the regulator has to be the same type as the welders use for propain the regulator has to be a direct connection to the tank if the tank is a small one this could be a pressure flow problem i use a 9kg bottle i tryed a 8kg and it ran out of steam because the forge demand was greater than the botltle could put out ,

 

hope this may help

cheers tell

[KPeacock]

I'll change the set-up a bit and move the pressure regulator closer to the tank. I didn;t think that it would make much of a difference.

 

As far as the shut-off globe valve goes, I'm not so sure it's even necessary. its right next to the needle valve and only a couple feet from the tank valve. i have three valves within three feet. i guess safety is important though.

[Mike Blue]

If you have one of the large thread, hand tightening general for home BBQ users, black plastic safety connectors for your tank to hose connection, it is possible that the connector is not completely disconnecting the safety spring valve inside the brass body of the tank valve. You may need to switch to one of the old style tank connectors that threads to the inside of the brass body valve on the tank.

 

I always wondered why I couldn't get BBQ style bottles to put out enough pressure until I realized that the center nipples on the new fangled black plastic tank connections were just long enough to let out enough pressure for a BBQ, but not nearly enough for what we'd use it for.

[KPeacock]

Mike,

 

I'll take a closer look at this this evening. This makes more sense to me as the culprit.

 

Thanks,

 

Kris

[KPeacock]

After changing the tank coupling I think the problem has been solved. I ran the forge for a while and hammered out a rough blade using a medium carbon steel and decided I'd practice a bit more at the welding and as the forge was coming up to temp, my blower failed. I'm no electronics genious, but it has been my experience that any time the smoke is let out of an electrical device, it is ruined beyond simple repair. Apparently, the duty cycle of the wife's old hair dryer is far less than what is required to run a forge. The remaining parts neede to assemble another venturi style burner arrived today, so I should be back to work tonight or tomorrow some time. I do like the adjustability of the forced air burner, but after lastnights failure, I'm beginning to see additional benefits to a naturally aspirated burner!

[Chris Meyer]

Another possibility is that the tank was freezing up. If your flow rate is too high for the tank, it will freeze up and you'll see ice on the outside of the tank. If that's the problem, your best bet is to get a bigger tank. (I had to switch to a 100lb tank for my forge.) Another solution is to put the tank is a barrel of water to dissipate some of the cold.

[KPeacock]

Chris,

 

I suspected freezing at first, bu have ruled it out. Even with a warm tank (ambient air temp of 60°F) and sitting in a water bath of at about 75°F the tank would still do this. It happens when adjusting flow rates and generally happens quite soon after firing the forge up. By quite soon, I mean on the order of 20-30 seconds or so. I think Mike hit the nail on the head. I"m not 100% sure as my blower failed. I'm working on a different blower set-up now.

 

thanks,

[cdent]

If it runs ok then shuts down to a trickle, it might be the opd valve. I can tell when it kicks in on my grill. I have to shut it down, release the line pressure and restart. Luckily, it doesn't happen with the forge. I'd like to go with a hundred pound tank, but for now it's bbq tanks.

 

Good luck with it, Craig

[KPeacock]

I've got my eye out for a 100# tank as well. I've sen a few of them on Craigslist in the past for free or cheap. At the time I didn;t have a need for them though. I do have natural gas plumbed out to my garage for the furnace, but I'm a little bit hesitant to use NG as a fuel source. I'll look into it further, but it seems as though it is nowhere near as common. Perhaps it's simply a matter of utility, or perhaps it has to do with the BTU rates. I'm sure there is a reason though.