(July 14, 2019 at 2:51 am)onlinebiker Wrote:(July 13, 2019 at 8:15 pm)Fireball Wrote: If I read this right, there is a 5 foot difference in the heads at either end. I don't know the viscosity of maple sap, but it may be just high enough to slow the flow to some small value (combined with pressure drop from friction of the fluid with the pipe). Have you tried it with plain water? That would answer the question about viscosity, because water would flow, regardless, though it might be slow. Next part- once you put a suction on the line, the flow, once started, will continue due to the siphoning effect of the fluid flowing in the line. More fluid on the source side overcomes the viscous flow and/or pipe friction. What kind of pipe are you using?Maple sap is usually about 2 % sugar - but it does the same with water.
The pipe is a Silicon based semi rigid tubing made specifically for syrup use. It will withstand 100 psi and does not collapse with 25 inches of mercury vacuum
(July 13, 2019 at 10:57 pm)Anomalocaris Wrote: 1. How far is the tap on the side of the tank from the bottom of the tank?
Less than 2 inches
2. Is there any air holes on the top of the tank preventing vacuum build up inside the tank?
There is an access hatch - it can be removed and does not affect the situation.
3. Is there any air trap in the line?
Not sure what you mean.
(July 13, 2019 at 11:42 pm)polymath257 Wrote: If there is air in the hose, you won't get a flow. The suction bring the water or sap through to the point that such gaps are eliminated, allowing flow.
How would air in the line prevent flow?
If that were the case a sink would not drain when you pulled the plug.....
Not just air in the hose, but an actual air trap. That’s where somewhere along it’s path the hose bows upwards to form a hump. If the top of the hump is higher than the top of the liquid level in the tank, You have an air trap. If you apply suction to the end of the hose, you drop the pressure of the air in the air trap. This imbalances the pressure of the air in the tank and pressure of the air in the hose, and the air pressure in the tank will force the liquid up over the hump, then siphoning effect will take hold and the tank will drain.
If you top up the tank until the liquid level in the tank is higher than the hump in the hose, then the hydrostatic pressure of the water will overcome the air in tthe hump and the tank will drain naturally.
