OT: Physics/hydraulics of water and barrel

run a long length of hose that comes up to the level you want to fill....Now the trick is: you'll need to have a length of hose running relatively straight (slight downgrade). This length of sloping hose should probably be at least twice the length of the vertical portion of the hose.

So....With the barrel on the ground....run some hose up to the 20foot level and then have 50feet of sloping hose.

The idea here is that once you have the hose filled with water....the longer length of horizontal hose will run in to the barrel and will draw water up from the barrel. The trick is to get the hose filled with water (attach pump at bottom and once it is full, let her go on her own!

This is the same as taking a 5ft piece of hose and putting the whole thing in your above ground swimming pool (on top of the cover with all the rainwater sitting on it)....once the hose is full you just hang one end off the end of the pool and gravity will help you draw the water out.

If those hippie romans can figure it out....so can us rednecks! ha!

Nope, that will not work. A siphon will not draw water up from a lower barrel. A siphon (hose) will expel water only from the lower of the two hose ends. Does not matter if the hose is 10 feet long or 10,000 feet long. For a hose that is completely filled with water the only thing that matters is the height difference between the two ends of the hose. The lower end (no matter how long the hose) will expel the water.

Tom

Yes, it *is* nonsense, in the context of the situation described by the OP. He's talking about pumping water into a 55-gallon drum, elevated eight to ten feet above the ground. Now a standard 55-gal drum is about 3 feet tall, which, incidentally, means that the maximum pressure that can be exerted by the water in the tank is that of a 3-foot water column, and the effort to overcome that pressure is exactly equivalent to that required to lift water three feet. With me so far? The OP evidently has a pump that can lift water as high as the top of the tank (thus approx 11 to 13 feet above ground). Any pump that can lift water 11 to 13 feet, can certainly lift it three feet.

Put another way: if the pump develops enough pressure to pump water up to the top of the tank, then it can pump water into the bottom of the tank.

Well, obviously... but where's the 100 psi gonna come from, in a water column that's only three feet tall? I make that out at around one-point-two psi.

Not quite. If filled by the top hole the lift is constant but maximum. If filled by the bottom hole the lift is not constant but increases as the top barrel is filled.

I think the question was what was more efficient i.e. use less energy in which case the pressure is (somewhat) irrelevant to the problem

"Mike Romain"

| > >Water is heavy. How many PSI comes out that bottom hole? | > >

| > >The pump must first overcome this pressure before it can start filling | > >the tank. That can easily mean the pump will 'run backward' and fill up | > >the truck if the top tank has enough weight in it. | > >

| > Nonsense. | | Well you know, everyone else has explained why I was wrong, but you are | wrong here with that snip quote. | | That is 'not' nonsense. If there is 100 psi in the line and the pump | can only pump 50, it will flow backward.

But if you use the same pump to fill the tank in the first place there would be no water in the tank to flow backward.

Put a "T" at the bottom with a check valve to the pump side. Pump all the water in you want without back flow to the pump.

BTW that's the way it's been done with municipal water tower for years.

"Mike Romain"

| So if you have a pump that can only generate 'say' 50 psi, then your | truck tank will fill up at a rate of 50 psi out of that 'say' 100 psi | line if there is no backflow valve.

PSI is pressure a static number, flow rate (which is effected somewhat by PSI) is another matter.

If your head generates 100 psi then a 50 psi pump will not work.

Correct

Ah yes, finally the proper answer, i.e, it is slightly less pressure to begin with to fill thru the bottom hole until it is identical when the barrel is full. Assuming the barrel is about 4' high there would be about 2psi differential pumping pressure at the bottom of the empty barrel than at shutoff when it is full. Filling through the top hole will have the same pressure of whatever throughout the filling.

Harry K

And the pressure might go up a bit as density does go up a small amount for colder water. Densist at 4 degree (F or C?) IIRC from 50 years ago.

Harry K

It also matters if you want to know whether pushing on the pump handle is going to move water, or bend the handle. If you're talking about PSI, the cross-section of the hose doesn't matter, only the vertical head. If you're talking about total force working against the pump, then you device the volume of water displaced by each stroke by the length of the stroke, and multiply the result by the pressure. In no case does using a smaller hose make things easier.

--Goedjn

Well, it's a lot like the pistons in a kiddie-toy, except without the piston part..

Highest density for water is at 39 degrees F, so your 4 must be in C.

It's life-and-death knowledge for some - particularly those who rely on the ice-bridge to get to the mainland. Like on Mackinac Island. I know of entire sled-loads of hay, complete with driver and team of horses, that have been lost through the ice bridge to St. Ignace due to an upwelling of 39-ish degree water spewing up from the bottom of the lake and eating the ice away from beneath, silent and invisible until the "ground" you're on literally falls out from under you.

In this case, the "pistons" are the top of the "high" water and the output of the pump.

Crap...really?

Figured that there would be more gravity acting on the longer sloping run of hose that it would run out and draw up.

That's what I get for trying to think after eating cheesies! Dam them and their preservatives!

finally? He had a correct answer within ten minutes. Why this thread has grown (or should I say GROAN?) so long is a mystery to me!

I think you meant 31 ft. Shallow well pumps work very reliably at 26' depth here (2,000 ft).

Harry K

Key words here are "head pressure"---there would be no difference in the force required to fill the upper barrel from any of the three bungs other than "line"loss (if you shortened the hose to fill from the lower bung you would have less line loss and therefore require less force to fill the drum, but the difference wouldn't be measureable without NASA scientists and equipment).