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Discussion Starter #1
This is cool! We have an 1100 gal. "mother" tank that we had a wet-valve or wet-leg installed in...while it was full!

Now we can fill any tanks with it...even those "illegal" ones that "can't" be filled from propane vendors...not that I'd ever do that:D:

Pic 1: tank and hose overview
Pic 2: lower liquid valve
Pic 3: filling unit

A bit pricey ($600, parts and labor), but handy as heck!

:thumb:
 

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Hope is not a method
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Whats the tank pressure exchange ratio? Curious to see what propane is all about, never had it. Makes sense to be able to fill smaller tanks for other uses.

Excellent purchase.
 

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Lone Wolf
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only reason those other tanks were illegal was they didn't have an overfill valve inside. ifin ya get a flow meter to register how many gallons ya put into the little tanks the "illegal" tanks are perfectly fine. just don't turn on yur fill an' walk away is all.
 

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Discussion Starter #4
Whats the tank pressure exchange ratio? Curious to see what propane is all about, never had it. Makes sense to be able to fill smaller tanks for other uses.

Excellent purchase.
I'm not sure what you mean by that?

:confused:
 

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Hope is not a method
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Whats the main tanks pressure versus the fill tank pressure? I'm assuming the main tank must be higher pressure to fill a smaller tank to a certain max pressure fill using a regulator?

Kinda like the air conditioner system on a car, can only fill from the low pressure side because of the pressure ratio.
 

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Free Mason
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For the older tanks there is a scerw in the side of the valve. When you are filling the tank open this screw a few turns. This lets out some gas, when it sputters liquid stop filling the tank and close the screw. The tank is now safeley filled to 80%. No need to weigh or measure flow.
 

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Discussion Starter #7
Whats the main tanks pressure versus the fill tank pressure? I'm assuming the main tank must be higher pressure to fill a smaller tank to a certain max pressure fill using a regulator?

Kinda like the air conditioner system on a car, can only fill from the low pressure side because of the pressure ratio.
OK...gotcha. I THINK the main tank is something like 110 psi...not sure though. The tank to be filled is zero pressure.

Propane is strange though. Had a small leak in a full 100 gal tank so we had to replace the bad valve. We drained off the pressure and replaced the valve, but still had approx. 70% of the propane left because of the "boiling" characteristics of propane!

:confused:
 
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I started stocking propane tanks a few months ago. The best deal I found locally was about $43 for a full tank that was in very good condition (still had original paint, I see some that are spray painted over rust so they look new).
After buying a couple, I found out that some places are filling 20 lb. tanks to only 15 lbs. I don't know if this is a new ordinance, or if some of them are just being extra cautious.
Anyway, I recently stared going to Lowes and buying brand new tanks,for about $33, then getting them filled to 20 lbs. for another $17. It works out to be a little more money, but I feel better knowing that have properly filled,new tanks that I know haven't been mis-treated. :thumb:
 

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You can get an older tankk from yard sales, flea markets, take it to the gas stations that exchange them for filled ones, cost about $20, you get a newer tank, and then keep that and get it filled from a dealer.
 

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Jack of all trades
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My dad's 500Gal. tank already had the wet leg so dad asked the delivery driver about setting it up to fill the 20lb tanks. Next time we had a delivery, the driver brought the hose/fittings and put 'em on. Only charged dad $40, guess he was lucky!

You can also buy a screw-on adapter to refill the 1lb "disposable" propane tanks. You refill them from the 20lb tanks (have to turn the 20lb upside down). I got mine at Tractor Supply for ~$22, Harbor Freight also has them.

Roger
 

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Whats the main tanks pressure versus the fill tank pressure? I'm assuming the main tank must be higher pressure to fill a smaller tank to a certain max pressure fill using a regulator?

Kinda like the air conditioner system on a car, can only fill from the low pressure side because of the pressure ratio.
In liquid propane tanks the ability to fill is not derived from pressure but the fact that the fuel is liquid. (Notice that the wet leg is on the bottom of the mother tank) When the fill valve is attached to the smaller tank and opened, liquid propane is allowed to flow into the smaller tank. A small amount boils into gas until the small tank reaches the pressure that will keep the liquid from boiling (177psi @ 100 deg. F)
 

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Hope is not a method
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In liquid propane tanks the ability to fill is not derived from pressure but the fact that the fuel is liquid. (Notice that the wet leg is on the bottom of the mother tank) When the fill valve is attached to the smaller tank and opened, liquid propane is allowed to flow into the smaller tank. A small amount boils into gas until the small tank reaches the pressure that will keep the liquid from boiling (177psi @ 100 deg. F)
So the boil off rate is not very fast so the pressure built by the boil off doesn't effect the propane transfer? Also, the boil off that makes the pressure/gas is what the propane burner actually burns (the gas not the liquid)? Explains why the use valve is on top and not the bottom and the transfer valve on the bottom. Cool didn't know that, learn something new everyday!
 

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Looks like rain to me.
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Is there a way to make that refill system "portable"? If after the "Big One" you came across an abandonedtank with propane inside., could it be hooked up to remove some of the gas.

A 250 gallon tank might be difficult to move, but a couple small ranks might "Get'er done"
 

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I found that many people get rid of old propane tanks and they collect in a pile at the dump. I pick up a couple of these old tanks and trade them at Lowes just by doing a tank exchange. I get a new style tank filled for about $16.
 

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So the boil off rate is not very fast so the pressure built by the boil off doesn't effect the propane transfer?Correct, and by having the vent screw open the gas is forced out as liquid fills from the bottom up Also, the boil off that makes the pressure/gas is what the propane burner actually burns (the gas not the liquid)? Explains why the use valve is on top and not the bottom and the transfer valve on the bottom. Cool didn't know that, learn something new everyday!
Correct, which is why home tanks are mounted horizontally, it increases the surface area of liquid which can boil off. Remember that when liquids become gaseous they cool driving the temperature of the liquid down. In the bitter cold winter areas it isn't uncommon for smaller tanks (50-100 gallons) to not be able to provide enough fuel for heating due to the low ambient temp, and their self induced cooling.

As for making this 'portable' I would personally think it quite hazardous to attempt installation on a tank that had propane in it. (I was wondering how they managed with the OP's tank being filled.)
 
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