False Bottom Question

[Flounder]

So I have been looking at pictures of MLT's that use a false bottom and I am a bit confused about how this works. It looks like the tube connecting the FB to the valve on the MLT is above the convex shape of the FB. If this is so, and all of the wort collects at the bottom, how does the wort travel up into the valve? Not even sure if the wording of this question makes any sense.

 

[The Pol]

Well, there is plenty of pressure (head) on the wort from above. This pushes the wort up and out of the tube. This is the same concept that is used with a dip tube in a keggle. The tube isnt ABOVE the false bottom, the tube is connected to the center of the false bottom.

Once the fluid level drops below the valve, but still above the false bottom, it will continue to flow due to the syphon... fluid dynamics.

 

[Flounder]

You had me at fluid dynamics. Being of the not so smart variety, I'll trust your explanation. Seriously, it sounds like gravity does the work.

 

[The Pol]

Gravity, head pressure and then at the very end the syphon. The longer the hose on the output, the speedier the outflow, better syphon, basically will suck the wort out of the vessel.

I use one, they work awesome for fly sparging.

 

[TXCrash]

Fluid Dynamics 101:

Any volume of water which has the same height from inlet to outlet (Top of Swimming pool to bottom of swimming pool vs. top of PVC pipe to bottom of pipe vertically filled with water) will have the same pressure at the bottom. To prove this to yourself just think - if you inserted the PVC pipe into the swimming pool, wouldn't the pressure at the bottom of the pipe be the same as the bottom of the pool?

Water does not care what path it takes, be it a straight down path or a twisty one. It only cares about the difference in the height of the top of the water and the height of the bottom of the water. This is called total head, expressed in feet.

Any system has restrictions. These can be mathematically converted to feet of water.

As long as total head is greater than the restriction, flow will occur.

In other words - what the hydraulic system sees is a 3 foot solid pipe if you have 3 feet of elevation difference between the top of the water and the end of your hose.

 

[Jaybird]

A siphon is a siphon. It doesn’t matter what's above it, I.E the false bottom. Make sure the drain is longer and lower than the pick up, and you’re good to go.
JJ

 

[Denny's Evil Concoctions]

A siphon is a siphon. It doesn’t matter what's above it, I.E the false bottom. Make sure the drain is longer and lower than the pick up, and you’re good to go.
JJ

And no leaks in the fittings/tube, cause once the fluid level drops to that of the fittings etc, any leaks will allow in air, killing the siphon.

 

[Flounder]

Thanks for the replies. I am now woefully aware of my ignorance of basic physics.