O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


--
Member AAAAAAAA
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"Jeepers" wrote in message
...
O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?

When you start to fill the top barrel, the pressure required will be less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

It isn't a matter of how much water is in the top barrel. It's a matter of
the head -- the vertical distance the water has to be pushed up. That works
out to roughly 15 psi for every 39 feet of vertical head, if you want to
calculate the required pressure. You could complicate things by sticking the
hose in the top bung and letting it hang down inside the top barrel, but
please don't. g

Ed Huntress

In article ,
"Ed Huntress" wrote:

When you start to fill the top barrel, the pressure required will be less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

It isn't a matter of how much water is in the top barrel. It's a matter of
the head -- the vertical distance the water has to be pushed up. That works
out to roughly 15 psi for every 39 feet of vertical head, if you want to
calculate the required pressure. You could complicate things by sticking the
hose in the top bung and letting it hang down inside the top barrel, but
please don't. g

Ed Huntress

So, actually filling the barrel would require more force to use the top
hole?

Does the head not include larger amount of water in the barrel?

--
Member AAAAAAAA
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"Jeepers" wrote in message
...
In article ,
"Ed Huntress" wrote:

When you start to fill the top barrel, the pressure required will be
less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

It isn't a matter of how much water is in the top barrel. It's a matter
of
the head -- the vertical distance the water has to be pushed up. That
works
out to roughly 15 psi for every 39 feet of vertical head, if you want to
calculate the required pressure. You could complicate things by sticking
the
hose in the top bung and letting it hang down inside the top barrel, but
please don't. g

Ed Huntress

So, actually filling the barrel would require more force to use the top
hole?

Yes, by a small amount.


Does the head not include larger amount of water in the barrel?

No, and this is the part that sounds counter-intuitive, which is why a
question based on this point often shows up on high-school Physics exams.
g

The pressure required depends only on the vertical height of the water
column -- the head -- not on the volume of water. The pressure required is
the same whether you're filling a mason jar or a 55-gal. drum. And it's the
same whether you're filling it through a fire hose or a soda straw.

Ed Huntress

In article ,
"Ed Huntress" wrote:

So, actually filling the barrel would require more force to use the top
hole?

Yes, by a small amount.


Does the head not include larger amount of water in the barrel?

No, and this is the part that sounds counter-intuitive, which is why a
question based on this point often shows up on high-school Physics exams.
g

I never had high school physics :^( Why I asked ;^)

O.K. At this point I admit I'm no doctor of physics. I also have to
admit it was my idea to install the top fill bung thinking it would be
easier to fill because I wouldn't be filling against a barrel full of
water. So I lose the argument. HOWEVER... I also want to leave the hose
attached to the top fill bung so I don't have to re-attach a water
filled, running, hose back to the cabin.

Thanks!



The pressure required depends only on the vertical height of the water
column -- the head -- not on the volume of water. The pressure required is
the same whether you're filling a mason jar or a 55-gal. drum. And it's the
same whether you're filling it through a fire hose or a soda straw.

Ed Huntress



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"Jeepers" wrote in message
...
In article ,
"Ed Huntress" wrote:

So, actually filling the barrel would require more force to use the
top
hole?

Yes, by a small amount.


Does the head not include larger amount of water in the barrel?

No, and this is the part that sounds counter-intuitive, which is why a
question based on this point often shows up on high-school Physics
exams.
g

I never had high school physics :^( Why I asked ;^)

O.K. At this point I admit I'm no doctor of physics. I also have to
admit it was my idea to install the top fill bung thinking it would be
easier to fill because I wouldn't be filling against a barrel full of
water. So I lose the argument. HOWEVER... I also want to leave the hose
attached to the top fill bung so I don't have to re-attach a water
filled, running, hose back to the cabin.

Thanks!

Well, you may not have studied physics, but it sounds like you did pretty
well in common sense. I wouldn't want to try to re-attach that hose, either.
d8-)

FWIW, I don't know exactly how high a 55-gal drum is, but if it's, say, 4
feet, the difference in pressure required to fill it from the top versus the
bottom is only around 1.5 psi. And that only applies when the barrel is
empty, and you're just starting to fill it. When the water reaches the top
of the barrel, the required pressure is the same whether you're filling from
the top or the bottom. So it makes no practical difference, if you intend to
fill the barrel. It may fill a little faster from the bottom but you still
need the same amount of pump pressure to fill it to the top.

Happy hunting.

Ed Huntress

In article ,
Jeepers wrote:
water. So I lose the argument. HOWEVER... I also want to leave the hose
attached to the top fill bung so I don't have to re-attach a water
filled, running, hose back to the cabin.

And you have thus found the difference between engineering and physics.
Physics correctly states that it's less effort/energy to fill the tankt
throught the bottom hole. Engineering notes that it's not that much more
energy/effrot, and that there are other considerations in the practial
implementation in favor of the upper hole.

--
Cats, Coffee, Chocolate...vices to live by

"Jeepers" wrote: (clip)I also want to leave the hose attached to the top
fill bung so I don't have to re-attach a water filled, running, hose back
to the cabin. (clip)
^^^^^^^^^^^^^^
I suggest filling through the same hose that you use to drain. If you put
on a Tee and a valve, you get the best of both worlds. (1.)Slightly less
pumping pressure during filling (2,) You don't need an extra hose running to
the top of the drum (3.) You don't have to deal with a hose full of water
that's trying to drain the tank while you're hooking it up.

I missed the staff meeting but the minutes show Jeepers
wrote back on Wed, 24 Nov 2004 10:32:27 -0600
in rec.crafts.metalworking :

I never had high school physics :^( Why I asked ;^)

O.K. At this point I admit I'm no doctor of physics. I also have to
admit it was my idea to install the top fill bung thinking it would be
easier to fill because I wouldn't be filling against a barrel full of
water. So I lose the argument. HOWEVER... I also want to leave the hose
attached to the top fill bung so I don't have to re-attach a water
filled, running, hose back to the cabin.

Actually, while it may not be "easier" to pump water the additional
distance to the top, the "hydrostatic load" is less. May not be a problem
when you are pumping into an empty barrel, but when you start pumping fluid
into a full pipeline, it isn't going to move. Pressure builds as water
doesn't compress, and until the stationary water "gets out of the way"
there is no place for the new water to go.
I learned about this from a biography of Mr LeTournou, who learned it
the hard way by coming back the next day and switching the pump back on, at
full power. I don't remember if he blew out the pump or a piece of pipe,
but it was a very expensive lesson

Thanks!

--
pyotr filipivich.
as an explaination for the decline in the US's tech edge, James
Niccol wrote "It used to be that the USA was pretty good at
producing stuff teenaged boys could lose a finger or two playing with."

In article , Ed Huntress says...

So, actually filling the barrel would require more force to use the top
hole?

Yes, by a small amount.

Which is the distance between the top of the barrel and the
outlet of the hose which is above the barrel's top rim.

If the hose were looped up over the top and dropped into the bottom
of the barrel, they would be exactly the same once the flow
became continous - not counting the flow resistance of the
hose.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"Ed Huntress" wrote:


Does the head not include larger amount of water in the barrel?

No, and this is the part that sounds counter-intuitive, which is why a
question based on this point often shows up on high-school Physics exams.
g

The pressure required depends only on the vertical height of the water
column -- the head -- not on the volume of water. The pressure required is
the same whether you're filling a mason jar or a 55-gal. drum.


And it's the
same whether you're filling it through a fire hose or a soda straw.

Only if you presuppose a zero flow rate. Fluid resistance will be
higher in the soda straw for any real flow rate. [I have no Idea what
additional force is required to keep the fire hose from collapsing to
it's flat shape is either.]

OTOH the WORK required is always higher to fill through the top bung.
jk

"jk" wrote in message
...
"Ed Huntress" wrote:


Does the head not include larger amount of water in the barrel?

No, and this is the part that sounds counter-intuitive, which is why a
question based on this point often shows up on high-school Physics exams.
g

The pressure required depends only on the vertical height of the water
column -- the head -- not on the volume of water. The pressure required
is
the same whether you're filling a mason jar or a 55-gal. drum.


And it's the
same whether you're filling it through a fire hose or a soda straw.

Only if you presuppose a zero flow rate.

Again, that's a complication that doesn't address the basic principle that
was being asked. d8-)

Ed Huntress

"Ed Huntress" wrote in message
...

When you start to fill the top barrel, the pressure required will be less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

Jeez, *there* was a screwed-up description. Let me try again: When you start
to fill the top barrel, filling it through the bottom bung will require less
pressure than filling it through the top bung.

Sorry.

Ed Huntress

Ed Huntress wrote:
"Jeepers" wrote in message
...

O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


When you start to fill the top barrel, the pressure required will be less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

It isn't a matter of how much water is in the top barrel. It's a matter of
the head -- the vertical distance the water has to be pushed up. That works
out to roughly 15 psi for every 39 feet of vertical head, if you want to
calculate the required pressure. You could complicate things by sticking the
hose in the top bung and letting it hang down inside the top barrel, but
please don't. g

Ed Huntress


Hey Ed, what about the added FLOW backpressure in the longer hose needed
to reach the upper bung. That might increase the pumping pressure
required when filling through the upper bung, huh?

The OP did distinguish them as the "lower fill hose" and the "upper fill
hose" so I've got a perfectly valid reason to conclude that he's
describing two different length hoses. G (Course they might be two
different diameters too.....Aw ferget it...)

Jeff

P.S. while I'm here, can someone point me to a chart or formula to find
for the flow rate of water out of the end of a known diameter horizontal
pipe based on how far the end is above the ground and how far away from
the end the water stream impinges on the ground. (Don't tell me to put a
bucket on the ground and time it, I know how to do that already G)

Thanks guys,

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

On Wed, 24 Nov 2004 12:08:03 -0500, Jeff Wisnia wrote:


P.S. while I'm here, can someone point me to a chart or formula to find
for the flow rate of water out of the end of a known diameter horizontal
pipe based on how far the end is above the ground and how far away from
the end the water stream impinges on the ground. (Don't tell me to put a
bucket on the ground and time it, I know how to do that already G)

Thanks guys,

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

The flow (GPM = gallons/minute) from a horizontal pipe of (inside) diameter d
(in) can be estimated by measuring how far from horizontal the stream has
dropped, y (in), at a distance x (in) from the end of the pipe and using the
formula GPM = 2.56 * x * d * d / sqrt(y).

Regards, Marv (brass rat '63 VIII)

Home Shop Freeware - Tools for People Who Build Things
http://www.geocities.com/mklotz.geo


--
HSM Freeware Programs at
http://www.geocities.com/mklotz.geo

"Jeff Wisnia" wrote in message
...
Ed Huntress wrote:
"Jeepers" wrote in message
...

O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


When you start to fill the top barrel, the pressure required will be
less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

It isn't a matter of how much water is in the top barrel. It's a matter
of
the head -- the vertical distance the water has to be pushed up. That
works
out to roughly 15 psi for every 39 feet of vertical head, if you want to
calculate the required pressure. You could complicate things by sticking
the
hose in the top bung and letting it hang down inside the top barrel, but
please don't. g

Ed Huntress


Hey Ed, what about the added FLOW backpressure in the longer hose needed
to reach the upper bung. That might increase the pumping pressure
required when filling through the upper bung, huh?

I think you have just overengineered the problem, Jeff, and your market
share is headed for China. g


The OP did distinguish them as the "lower fill hose" and the "upper fill
hose" so I've got a perfectly valid reason to conclude that he's
describing two different length hoses. G (Course they might be two
different diameters too.....Aw ferget it...)

Ok.

Ed Huntress

It takes 1 lb of pressure to push a column of water 27.8" up.
Roughly figure 1 lb of pressure =2 feet of rise
so it would take a little less then 5 lbs of pressure to push water up 10
feet.

"Ed Huntress" wrote in message
news
"Jeff Wisnia" wrote in message
...
Ed Huntress wrote:
"Jeepers" wrote in message
...

O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide
water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There
are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


When you start to fill the top barrel, the pressure required will be
less
than for filling it through the top hose. When the top barrel is nearly
filled, the pressure required will be the same either way.

It isn't a matter of how much water is in the top barrel. It's a matter
of
the head -- the vertical distance the water has to be pushed up. That
works
out to roughly 15 psi for every 39 feet of vertical head, if you want
to
calculate the required pressure. You could complicate things by
sticking
the
hose in the top bung and letting it hang down inside the top barrel,
but
please don't. g

Ed Huntress


Hey Ed, what about the added FLOW backpressure in the longer hose needed
to reach the upper bung. That might increase the pumping pressure
required when filling through the upper bung, huh?

I think you have just overengineered the problem, Jeff, and your market
share is headed for China. g


The OP did distinguish them as the "lower fill hose" and the "upper fill
hose" so I've got a perfectly valid reason to conclude that he's
describing two different length hoses. G (Course they might be two
different diameters too.....Aw ferget it...)

Ok.

Ed Huntress

Subject: O.k. got an argument to solve. Physics/Hydraulics.
From: "invntrr"
Date: 25/11/04 03:02 GMT Standard Time
Message-id: yXbpd.3540$6m2.2539@trnddc04

It takes 1 lb of pressure to push a column of water 27.8" up.
Roughly figure 1 lb of pressure =2 feet of rise
so it would take a little less then 5 lbs of pressure to push water up 10
feet.

The lb isn't a unit of pressure. It's a unit of force. But then we know that
you know that we know that you know you meant lb per square inch.
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)

Except for the three feet of additional head to get the water up the the top
hole, the pressures are the same. If you include the height of the barrel,
it would actually require less pressure to fill the barrel from the bottom
than pumping the water up to the top of the barrel first, at least until the
barrel is full.

--
Bob (Chief Pilot, White Knuckle Airways)

I don't have to like Bush and Cheney (Or Kerry, for that matter) to love
America

"Jeepers" wrote in message
...
O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


--
Member AAAAAAAA
American Association Against Acronym Abuse And Also Ambiguity.

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Fill it from the bottom, you will be raising the total volume of water less
than if you fill from the top.


" O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


--
Member AAAAAAAA
American Association Against Acronym Abuse And Also Ambiguity.

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Fill it from the bottom, you will be raising the total volume of water
less
than if you fill from the top.

Forgot to add if you climb to the top of the barrel you will also be closer
to the moon.


" O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?


--
Member AAAAAAAA
American Association Against Acronym Abuse And Also Ambiguity.

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In article .net,
"Ahernwill" wrote:

Forgot to add if you climb to the top of the barrel you will also be closer
to the moon.

Oh, hell, I knew THAT already.

--
Member AAAAAAAA
American Association Against Acronym Abuse And Also Ambiguity.

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"Jeepers" wrote in message
...
O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?

http://www.engineeringtoolbox.com/21_610.html

The static pressure of a column of fluid depends on only the height and the
specific gravity of the fluid. Therefore, the hose filled with the water
would create the same pressure at the bottom as the equivalent height of a
55 gallon drum filled with water. So the idea that all that water wanting to
come down is going to be harder to push against than the hose filled with
water is false. The bottom bunghole would require less force, until you
filled it to the top, at which point they would be roughly equal. In terms
of total work done, which was not the question, a lot of energy would be
wasted filling from the top, since the added potential energy of the water
would be converted into kinetic energy falling into the barrel, which
doesn't help us fill our barrel.

"ATP" wrote in message ...
"Jeepers" wrote in message
...
O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?

http://www.engineeringtoolbox.com/21_610.html

The static pressure of a column of fluid depends on only the height and the
specific gravity of the fluid. Therefore, the hose filled with the water
would create the same pressure at the bottom as the equivalent height of a
55 gallon drum filled with water. So the idea that all that water wanting to
come down is going to be harder to push against than the hose filled with
water is false. The bottom bunghole would require less force, until you
filled it to the top, at which point they would be roughly equal. In terms
of total work done, which was not the question, a lot of energy would be
wasted filling from the top, since the added potential energy of the water
would be converted into kinetic energy falling into the barrel, which
doesn't help us fill our barrel.

If an ammeter were connected to the pump, would there be increased
'draw' as the pump works harder and harder to overcome the increasing
weight of water in the drum (440 lbs (avoir) when fully filled)?
Connection to the bottom bung.

If you compare a stream of water exiting a hose that's looped over the
top and laid into the bottom of the barrel (so that you're siphoning
the water out of the barrel) to a stream of water fed from the bottom
bung - which would go farther? Which would have the greater force
(psi?)?

Which connection will give great pressure in the cabin- top or bottom
bung?

Phil, Bklyn.

"Phil Gilson" wrote in message
om...


If an ammeter were connected to the pump, would there be increased
'draw' as the pump works harder and harder to overcome the increasing
weight of water in the drum (440 lbs (avoir) when fully filled)?

It has nothing to do with the weight of water in the drum. The pressure
required is based on the height of the water column -- what is commonly
called the "head" in hydraulics problems like this.

The pump would have to work harder as the height of the head above the pump
increased. But it would be the same amount of extra work whether the column
was a hose or a big drum -- or a city reservoir, for that matter.

As I mentioned in an earlier message, this is counter-intuitive to many
people. A few physics experiments and demos often are devoted to it in high
school physics classes. A lot of us are surprised when we see it at work.

It relates to all kinds of useful, practical problems, and it's worth
looking it up and spending an hour or so to understand it.

Connection to the bottom bung.

If you compare a stream of water exiting a hose that's looped over the
top and laid into the bottom of the barrel (so that you're siphoning
the water out of the barrel) to a stream of water fed from the bottom
bung - which would go farther? Which would have the greater force
(psi?)?

The force in both cases depends upon the height of the outflow end of the
hose. If they're both located the same distance below the bottom of the
barrel, they both supply water at the same pressure.

All of this neglects the friction of water in the hose. It's best to ignore
that at this stage of discussion. At small flow rates, there would be no
difference in pressure whether the hose was fed by siphon, over the top of
the barrel, or tapped from the bottom of the barrel. That is, if the heights
of the outflow ends of the two hoses are the same.

Which connection will give great pressure in the cabin- top or bottom
bung?

They both give the same pressure. At high flow rates, the shorter hose will
give more volume and pressure, due to friction inside the hose. But don't be
distracted by that. The static pressure in both would be the same, and the
actual pressure at modest flow rates, for all practical purposes, would be
the same.

Ed Huntress

"Phil Gilson" wrote in message
om...
"ATP" wrote in message
...
"Jeepers" wrote in message
...
O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide
water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the
top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There
are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?

http://www.engineeringtoolbox.com/21_610.html

The static pressure of a column of fluid depends on only the height and
the
specific gravity of the fluid. Therefore, the hose filled with the water
would create the same pressure at the bottom as the equivalent height of
a
55 gallon drum filled with water. So the idea that all that water
wanting to
come down is going to be harder to push against than the hose filled
with
water is false. The bottom bunghole would require less force, until you
filled it to the top, at which point they would be roughly equal. In
terms
of total work done, which was not the question, a lot of energy would be
wasted filling from the top, since the added potential energy of the
water
would be converted into kinetic energy falling into the barrel, which
doesn't help us fill our barrel.

If an ammeter were connected to the pump, would there be increased
'draw' as the pump works harder and harder to overcome the increasing
weight of water in the drum (440 lbs (avoir) when fully filled)?
Connection to the bottom bung.

It's displacing some water but really not "lifting up" 440 lbs of water.

In article ,
Phil Gilson wrote:

[ ... ]

If an ammeter were connected to the pump, would there be increased
'draw' as the pump works harder and harder to overcome the increasing
weight of water in the drum (440 lbs (avoir) when fully filled)?
Connection to the bottom bung.

It would increase proportional to the increasing *height* of the
water -- but it would not get as high as in the case of pumping water
over the top of the drum.

Remember that that 440 lbs would be pressing on the entire
bottom of the drum, while the bung would represent about 3.14 square
inches (assuming the bung was 2" diameter). And the hose would be even
smaller, (only 0.916 square inches for 1/2" ID. What's the diameter of
the drum's inside? Something like 20"? If that is right, then it has
an area of 314.16 square inches, so the hose has only 1/1600th of the
area of the drum -- so (at the level of the bottom of the drum) it would
have only a force equivalent to 0.275 pounds. It does not make any
difference what the size of the drum is, only the height of the water in
it, so the hose passing up beside it would have the same pressure
(pounds per square inch) as the water from the bottom bung only when the
level of the water in the hose reaches the level of the top of the water
*in* the drum.

If you want to prove this, take a drum, with the fitting in the
bottom connected to a clear hose, which is brought up beside the drum.
Fill the drum to say 3/4 full. Now, look at the water in the hose
beside the drum. It will be at the same level as that in the drum -- no
matter what the difference is between the diameters. If it worked as
you seem to expect, the water in the drum would overbalance that in the
hose, and the water level would be much higher in the hose -- or go
spraying out the top of the hose, if there were not sufficient length.
It doesn't, so the pressure (pounds per square inch) is independent of
the size of the drum or the hose. Yes, the overall force on the bottom
of the drum would be larger, because there are so many more square
inches there.

If you compare a stream of water exiting a hose that's looped over the
top and laid into the bottom of the barrel (so that you're siphoning
the water out of the barrel) to a stream of water fed from the bottom
bung - which would go farther? Which would have the greater force
(psi?)?

There, you would be losing some flow to the friction of the
water inside the hose. Other than that, it would be the same, because
the water in each side of the loop will be balancing that in the other
side.

Which connection will give great pressure in the cabin- top or bottom
bung?

In the cabin? You mean which would give more flow to fill the
drinking glasses? Other than the friction in the hose, it should be
equal -- until the water gets below the level of the top bung.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
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--- Black Holes are where God is dividing by zero ---

Thanks to all who contributed. Ya made a believer outta me! Thanks again.

--
Member AAAAAAAA
American Association Against Acronym Abuse And Also Ambiguity.

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Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?

As you have discovered, this question is of less value
than some of the other questions, such as "will I need
to disconnect and reconnect hoses?"

Another question I would ask is "if the top hose splashes
into the barrel without a full siphon connection, would I
be in for less trouble with a small centrifugal pump?" I'd
expect having the water trying to backflow out the pump
everytime I shut it off would be more annoying than the
extra effort, or the complexity of adding checkvalves...

--Glenn Lyford

On Wed, 24 Nov 2004 10:10:38 -0600, Jeepers
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Just abit late maybe. But The bilge pump will struggle to fill that
tank. Give it a go, but it will be at best way under rated flow. They
are meant to work at 3-4' of water head.

O.k. got an argument to solve.

Have a 55 gal. barrel, on a 8 to 10 foot tall platform (to provide water
in deer camp).

It has three bungs. One on the bottom side (drain/flow). Two on the top
side. One for vent, one for fill.

There is another barrel in the bed of a pickup, full of water. There are
two pumps, one hand diaphragm type or one typical 12v bilge type. This
is the source of water to fill the high barrel.

The argument is that the water can be just as easily pumped into the
barrel through the drain bung, from below, as it could be through the
top fill bung. There is an assertion that the pressure inside the hose
is greater in the lower fill hose than in the upper fill hose, due to
the weight of the water in the barrel as it fills.

Which, if any, fill location would require more or less force to fill
this barrel: the top hole or the bottom hole?

In article ,
Old Nick wrote:

Just abit late maybe. But The bilge pump will struggle to fill that
tank. Give it a go, but it will be at best way under rated flow. They
are meant to work at 3-4' of water head.

I ended up using an old drill strapped to a 1x8 and a drill pump, the
kind that goes in a drill chuck. I have 110 in my truck. I took the
empty barrel to the creek bottom, drove right on down into the gravel
bed and hooked up the drill pump and dropped a hose over the side of my
1 ton 4x4, the other end went into the barrel in the bed. It took about
25 minutes to fill completely. I then drove back to camp and repeated,
except the tower barrel was a tad higher and the bottom barrel was a tad
lore, more on this later. The tower barrel has a single bung in the
bottom side and a vent in one of the top bungs covered in metal "lint
screen". The bottom bung goes to a PVC pipe down to a T, one goes to the
cabin, the other to a spigot. I would have pumped from the truck bed to
the tower, but hunting got in the way, so I had to drain the barrel in
the bed to one on the ground so I could use the truck. Anyway I ended up
pumping from the ground barrel to the tower barrel with the drill pump.
It pumped 50 of the 55 gallons into the tower tank before it reached
it's maximum head. But that was just fine.

Later I will add a second bung to the bottom side of the barrel for a
hot water line. I'll be using a RV propane hot water heater. But that is
a whole nuther story!

Thanks everyone who contributed in "learnin" me something!

--
Member AAAAAAAA
American Association Against Acronym Abuse And Also Ambiguity.

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