Freezing sap and a bottom-discharge tank

[Woodsrover]

I have a 350-gallon tank I'm going to use to collect sap at the bottom of my sugarbush. It has a funnel-shaped base and an outlet where I can connect a valve and port to connect my pump. I'm a bit worried that the sap will freeze in the valve at the bottom. I can cap off the port and simply pump out of the top of it but it would be a lot handier if I can use it as intended. The question is when sap freezes in a large vessel like this does it tend to freeze at the bottom first? The top? What's the chance my valve and port stay ice-free except for the coldest nights?

Thanks!

[Starks sugarbush]

We usually pump in evening and what runs and freezes will thaw as fresh sap runs we use stainless dairy bulk tanks so worst case a torch works

Sent from my SM-N920V using Tapatalk

[Big_Eddy]

The sap within the valve will freeze before the tank does. Unfortunate but true. Pumping out from above with a submersible or suction hose will be far less annoying.
A metal body (stainless, brass) valve will freeze much faster than a plastic body valve. But a metal body valve can be warmed (carefully) with a torch or heat gun. If you get it too hot though, you will melt the plastic / teflon seal within and it will leak. If you have a way to insulate the valve, you can reduce how often it freezes up, but it still will.

I have a valve on the bottom of my 200 gal head / storage tank that feeds directly to my float box. It freezes often enough. What I do with mine is warm it gently until it will turn, and not any more. Then I use an old broom handle to punch out the ice plug from the center of the ball. My tank is elevated and I usually work from below tapping a short section with a hammer. That way when I "break through" the dowel blocks the flow. I yank it back out and close the valve, then connect the hose and open again. With a pail underneath, I get a bit damp, but don't loose much sap. I can work from above and push it through into the pail, but that only works with a helper to close the valve once flowing.

[tcross]

would electrical heat tape wrapped around the outlet/ball valve work? you could only turn it on when you know it's going to freeze pretty good?!

[maple flats]

Heat tape will work, but in cases like that I either use a butterfly valve or 2 ball valves in series. With the 2 ball valve method, close the up stream valve, drain the downstream valve and close it, then open the upstream valve. A ball valve with sap or water in it will freeze and burst. When you close the 1st as I said, drain the second then close it (with the ball not full) then open the first, neither valve will burst when it freezes. Then, if the plumbing is copper you can slowly heat it to thaw, if plastic you need to heat it with a heat gun, not a torch.

[Woodsrover]

Thanks for the advice. We're tapping tomorrow so I'll let you know what happens.

[OldManMaple]

You may install a length of tubing on the outlet long enough to have the end higher than the tank. install a valve on the end and tie or secure it so the valve is above the liquid level in the tank. The tubing may freeze but the valve will be dry.

[GeneralStark]

I have had better luck with gate valves on outdoor tanks than with ball valves. My round bottom tanks have a male threaded outlet that I have put the gate valves directly on to. There is not much area to fill with sap so when they do freeze ( and valves will freeze first as others have said), the valves are not impacted. The last two seasons have surely tested these valves. In 2013 we had a rapid freeze after a small run and one tank was about half full and froze solid and the gate valve was fine. It took about two weeks of small runs for the ice in that tank to finally melt.

[Woodsrover]

You may install a length of tubing on the outlet long enough to have the end higher than the tank. install a valve on the end and tie or secure it so the valve is above the liquid level in the tank. The tubing may freeze but the valve will be dry.

Brilliant! I have extra 1" tubing and fittings to do this. The tank is sanitary-style tube fittings and I have a couple extra barb fittings for it. Tapping and running tubing tomorrow and will set this tank up at the bottom of the hill. With luck we'll be boiling Saturday night and Sunday.