Propane tank question

bodagocreek2 · December 22, 2013, 05:53:15 AM

I don't ever remember putting 20lbs of propane in a 20lb tank. It has always been 85% of whatever size tank you were filling, unless you left it in a cooler.The propane needs room for expansion, otherwise ka-boom.

beenthere · December 22, 2013, 08:29:57 AM

I believe putting 20 lb of propane in a tank does leave the room for expansion.

Several places for information about filling tanks can be found. An explanation of the filling with only 15 lbs is available too, but the tanks should end up when full with 20 lb of propane. One link, of many....

http://www.elivermore.com/propane.htm

John Mc · December 22, 2013, 10:23:42 AM

Quote from: bodagocreek2 on December 22, 2013, 05:53:15 AM
I don't ever remember putting 20lbs of propane in a 20lb tank. It has always been 85% of whatever size tank you were filling, unless you left it in a cooler.The propane needs room for expansion, otherwise ka-boom.

As much of a pain in the neck as the switch to OPD valves was, that's the purpose of them. No kaboom. They are designed to relieve pressure if it goes too high. You lose a little propane to the atmosphere, but no burst tank.

Rockn H · December 22, 2013, 10:42:46 AM

I think some of y'all should come give a school on filling propane tanks to the local propane companies here. lol They will not put more than 17 lbs in a 20lb bottle, or 85lbs in a 100lb bottle. The 100 lb bottle really kills me because I want all I can get in it. I have to "have it filled" and that means getting it by during the day when someone is there that "can" fill it, so naturally want to cut down on the refills. ;)

bodagocreek2 · December 22, 2013, 12:02:31 PM

I don't believe 60lb tanks and above have OPD valves, hence the 85%.

Gary_C · December 23, 2013, 02:26:09 AM

Quote from: John Mc on December 22, 2013, 10:23:42 AM
As much of a pain in the neck as the switch to OPD valves was, that's the purpose of them. No kaboom. They are designed to relieve pressure if it goes too high. You lose a little propane to the atmosphere, but no burst tank.

The OPD valves are an internal float valve that prevents you from exceeding the 85% liquid fill level. It is NOT designed to relieve pressure. There is a separate relief valve that was also there before the OPD valves became the required type of valve.

If you were to over pressurize the tank and as long as you were under the relief valve setting, the pressure could and will come to equilibrium by internally condensing some gas into liquid which will lower the pressure. That is true as long as the tank is allowed to cool.

John Mc · December 23, 2013, 03:54:09 PM

Thanks for the info, Gary. So the little spritz of gas I see/hear on occasion when someone is filling a tank is the OPD float hitting it's limit?

Gary_C · December 24, 2013, 04:35:16 AM

If the person doing the filling has the bleed valve open while filling, that spritz is probably the first bit of liquid to reach the 85% fill tube. I fill my own tanks by the bleed fill method, no scale or meter, and that spritz is my indication that the 85 % full level is getting close. As soon as the liquid comes steady out of the bleed valve, I know the tank is full.

Some people that fill tanks say you can hear the float slam shut, but I have not heard that. But most of my tanks have the old style valves without the OPD. I hate to fill tanks with the OPD because it takes so long to fill them. That mechanism of that float inside the tank restricts the flow when you are filling.

I am fairly sure the pumps they use for filling LP tanks have a means for reliving pressure back the the main tank while pumping the liquid into the tank being filled. If they did not, it's possible the relief valve on the tank could vent some of the pressure while filling.

ely · December 26, 2013, 04:23:40 PM

I have had one of those new type valve bottles on a grill that would not let gas come out no matter what you did. I found out I could hook it on my dads grill and it would work if you turned in on in a painfully slow manner.... I got me a new one and let him have it. we fill all of our own bottles at home.

when they first came out with the new ones, we could still get the old bottles filled for awhile if you stenciled FORKLIFT on the side of the old bottles.

js2743 · December 30, 2013, 07:04:52 PM

I get mine filled at tractor supply they only charge for what they put in the tank.

Randy88 · February 17, 2014, 06:55:34 AM

Gary, I also fill my own tanks, have for decades, when the new style valves came out, we just put the new valves into the old tanks. As for the different weights of gas put in the new tanks, that's mainly because of the new valves, the stem is longer into the tank and they've changed the float mechanism slightly and now the tanks don't hold as much, also some do it by weight and as a precaution they shut it off with a less percent full, some claim its got to do with insurance and safety, that way there is never the smell of gas leaking on a hot day.

The reason the new tanks don't fill as fast is because the float doesn't drop down as far on the new tanks as it did on the old tanks, they are supposed to fill slower, when they pump them full, its under pressure and that helps some too, but its still slower, with the float stem longer, you can no longer tip the new tanks to over fill them anymore like you used to be able to do, I think, but could be wrong, but since the new valves came out, they've even changed them a little too over time, I'm thinking lately the newest float stems are even longer still, to lower the percentage full even more, hence the reason why some tanks full are even lighter yet.

If you want to save the hassles of having to wonder if your tank is empty, go to an motor home place, buy the tank changeover kit, hook two tanks together and once one becomes empty, it automatically changes to the full tank, that way one is always empty before it changes to the full tank. I use the Hilton cordless heater on some of my equipment and I hook several tanks together to run the heater for a week or more to keep the engine warm in remote locations. I fill a lot of tanks each year, maybe 50 or more.

As for the bbq issue, not a problem, have the boys who come, kick in a few bucks and go buy another tank, do this a few times they come and before long, you've got a half dozen tanks on hand and more than enough gas to keep grilling all summer long and enough gas to warm the backhoe all winter long once they are full.

tmarch · February 27, 2014, 07:42:12 PM

Quote from: Gary_C on December 17, 2013, 07:20:51 PM
Sounds like a good plan Jim.

If they say anything, just tell them the gas was going to go bad setting over the winter anyway. You just saved them from cleaning out a mess in the spring. 8)

Heck that's what we call Tiger Meat around here, a lil onion, crackers and some adult beverages suit me just fine. Just so it's good hamburger.