I watched a couple of YouTube vids, and it appears they may have the 20lb one (older) that does not have that safety valve in it. They flip the bottle upside down to fill, and don’t think that will work nowadays, or will it??
Perhaps flipping tank causing liquid propane on that end would stop it from blocking the flow???
Never tried that, but I’ve put lots of anhydrous ammonia on corn where you off load a 2 ton wagon into a 500 lb applicator and it’s all about pressure. You have to open a pressure release valve on the tank you’re trying to fill so the liquid will run to the lower pressure.
That’s right, there is still pressure above the liquid when inverted, using that to push liquid into the smaller bottle.
Just gotta keep an eye on the weight being added to MT bottle. Check the bottle first for no pressure. Weigh it, then don’t exceed 1lb added. Doesn’t happen fast, which is a good thing.
In closing, when I would get a bottle filled at a place in BFT, they would just open the small vent screw on top and go till it was spewing vapors big time before they would cut it off…sheesh.
I have refilled quite a few from a twenty pound can. It helps to have a set of medical forceps. Use them to pull on the overpressure valve of the small bottle. That makes filling very quick. If you live near Beaufort I will lend you my “rig” for refilling.
You put the smaller tanks in the freezer for a little bit and that is what helps the gas move from the big tank to your smaller tank. I checked the weights of the 1lb bottle before and after filling. Works well for me.