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Re: OT: Physics/hydraulics of water and barrel
On Wed, 24 Nov 2004 18:21:07 -0500, "mabar"
<mabar@NoooSpamgrbonline.com> wrote: >The formula for the amount of pressure coming out of the bottom or top hole >is: > >Each foot of height provides about 0.43 PSI (pounds per square inch) of >pressure. > >The size or diameter of the tank does not matter. The pressure comes from >the height of the water column. The pressure for any given height difference >(from top tank to bottom tank) would be the same with any size tank. A >million gallon water tank 10 feet off the ground will have the same water >pressure draining as a 10 gallon tank, 10 feet off the ground. > If, and only if, the tanks are of the same height. If the million gallon tank is taller there will be more pressure. >Tom > >"Mike Romain" <romainm@sympatico.ca> wrote in message >news:41A4AC45.446CDF06@sympatico.ca... >> LOL! >> >> 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. >> Mike >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 >> 88 Cherokee 235 BFG AT's >> >via Encryption =---- > |
Re: OT: Physics/hydraulics of water and barrel
On Wed, 24 Nov 2004 18:21:07 -0500, "mabar"
<mabar@NoooSpamgrbonline.com> wrote: >The formula for the amount of pressure coming out of the bottom or top hole >is: > >Each foot of height provides about 0.43 PSI (pounds per square inch) of >pressure. > >The size or diameter of the tank does not matter. The pressure comes from >the height of the water column. The pressure for any given height difference >(from top tank to bottom tank) would be the same with any size tank. A >million gallon water tank 10 feet off the ground will have the same water >pressure draining as a 10 gallon tank, 10 feet off the ground. > If, and only if, the tanks are of the same height. If the million gallon tank is taller there will be more pressure. >Tom > >"Mike Romain" <romainm@sympatico.ca> wrote in message >news:41A4AC45.446CDF06@sympatico.ca... >> LOL! >> >> 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. >> Mike >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 >> 88 Cherokee 235 BFG AT's >> >via Encryption =---- > |
Re: Physics/hydraulics of water and barrel
"Jeepers" <moomesa@INVALIDfnbnet.net> wrote in message news:moomesa-B0ACCE.11591324112004@news-east.newsfeeds.com... > In article <41A4C55B.4F42B023@sympatico.ca>, > Mike Romain <romainm@sympatico.ca> wrote: > > > No way you lost the physics argument! > > > > You asked which is easier? This means less 'work'. > > > > If you had a real reservoir there and had 'say' for easy numbers 100 psi > > coming out the bottom pipe, then you 'first' have to build up 100 psi in > > the pump before the water will start to run back up that line. This > > takes power or 'work'. > > > > If you have an empty line with no pressure in it the pump only has to > > hold the pressure of the water column in the pipe when filling from the > > top. > > > > Yes if the tank was a void, then it would be lees 'work' to raise the > > water only to the bottom of the tank, but as soon as the tank has water > > in it, it is fighting back and the physics radically change! > > > > 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. > > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's > > Oh, great, now you've done it Ollie, I'm back to "confused". Ignore the confusing input. ;-) There isn't 100 PSI at the bottom of the barrel -- unless the barrel is something like 225 feet tall. You'll get a little under half a PSI for every foot of height -- that is, the vertical distance between the pump and the top of the water. If you dangle the hose over the top of the barrel, the top of the water for these purposes is the top of the hose. If you actually run the hose over the lip, and down to the bottom of the barrel, the top of the water is the level of the water in the barrel -- once you have filled the hose with water. The principle is the same as a siphon. So, fill the barrel wherever you want. It won't make a difference. I would fill it from the top bung so that it won't come out when you turn off the pump. Ray Drouillard |
Re: Physics/hydraulics of water and barrel
"Jeepers" <moomesa@INVALIDfnbnet.net> wrote in message news:moomesa-B0ACCE.11591324112004@news-east.newsfeeds.com... > In article <41A4C55B.4F42B023@sympatico.ca>, > Mike Romain <romainm@sympatico.ca> wrote: > > > No way you lost the physics argument! > > > > You asked which is easier? This means less 'work'. > > > > If you had a real reservoir there and had 'say' for easy numbers 100 psi > > coming out the bottom pipe, then you 'first' have to build up 100 psi in > > the pump before the water will start to run back up that line. This > > takes power or 'work'. > > > > If you have an empty line with no pressure in it the pump only has to > > hold the pressure of the water column in the pipe when filling from the > > top. > > > > Yes if the tank was a void, then it would be lees 'work' to raise the > > water only to the bottom of the tank, but as soon as the tank has water > > in it, it is fighting back and the physics radically change! > > > > 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. > > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's > > Oh, great, now you've done it Ollie, I'm back to "confused". Ignore the confusing input. ;-) There isn't 100 PSI at the bottom of the barrel -- unless the barrel is something like 225 feet tall. You'll get a little under half a PSI for every foot of height -- that is, the vertical distance between the pump and the top of the water. If you dangle the hose over the top of the barrel, the top of the water for these purposes is the top of the hose. If you actually run the hose over the lip, and down to the bottom of the barrel, the top of the water is the level of the water in the barrel -- once you have filled the hose with water. The principle is the same as a siphon. So, fill the barrel wherever you want. It won't make a difference. I would fill it from the top bung so that it won't come out when you turn off the pump. Ray Drouillard |
Re: Physics/hydraulics of water and barrel
"Jeepers" <moomesa@INVALIDfnbnet.net> wrote in message news:moomesa-B0ACCE.11591324112004@news-east.newsfeeds.com... > In article <41A4C55B.4F42B023@sympatico.ca>, > Mike Romain <romainm@sympatico.ca> wrote: > > > No way you lost the physics argument! > > > > You asked which is easier? This means less 'work'. > > > > If you had a real reservoir there and had 'say' for easy numbers 100 psi > > coming out the bottom pipe, then you 'first' have to build up 100 psi in > > the pump before the water will start to run back up that line. This > > takes power or 'work'. > > > > If you have an empty line with no pressure in it the pump only has to > > hold the pressure of the water column in the pipe when filling from the > > top. > > > > Yes if the tank was a void, then it would be lees 'work' to raise the > > water only to the bottom of the tank, but as soon as the tank has water > > in it, it is fighting back and the physics radically change! > > > > 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. > > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's > > Oh, great, now you've done it Ollie, I'm back to "confused". Ignore the confusing input. ;-) There isn't 100 PSI at the bottom of the barrel -- unless the barrel is something like 225 feet tall. You'll get a little under half a PSI for every foot of height -- that is, the vertical distance between the pump and the top of the water. If you dangle the hose over the top of the barrel, the top of the water for these purposes is the top of the hose. If you actually run the hose over the lip, and down to the bottom of the barrel, the top of the water is the level of the water in the barrel -- once you have filled the hose with water. The principle is the same as a siphon. So, fill the barrel wherever you want. It won't make a difference. I would fill it from the top bung so that it won't come out when you turn off the pump. Ray Drouillard |
Re: OT: Physics/hydraulics of water and barrel
In article <41A4AC45.446CDF06@sympatico.ca>, Mike Romain <romainm@sympatico.ca> wrote:
>LOL! > >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. The pressure at the bottom of the tank depends on the height of the column of water in the tank. The pressure required to pump water up to the elevated tank depends on the height above _ground_ to which it is being pumped. In the situation described (a 55-gal drum elevated some eight feet above the ground) it is necessarily the case that the height of the water column in the drum is *much* less than the height of the drum above ground, and any pump that develops enough pressure to lift water eight feet necessarily develops more than enough pressure to overcome that exerted by the water already in the tank. |
Re: OT: Physics/hydraulics of water and barrel
In article <41A4AC45.446CDF06@sympatico.ca>, Mike Romain <romainm@sympatico.ca> wrote:
>LOL! > >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. The pressure at the bottom of the tank depends on the height of the column of water in the tank. The pressure required to pump water up to the elevated tank depends on the height above _ground_ to which it is being pumped. In the situation described (a 55-gal drum elevated some eight feet above the ground) it is necessarily the case that the height of the water column in the drum is *much* less than the height of the drum above ground, and any pump that develops enough pressure to lift water eight feet necessarily develops more than enough pressure to overcome that exerted by the water already in the tank. |
Re: OT: Physics/hydraulics of water and barrel
In article <41A4AC45.446CDF06@sympatico.ca>, Mike Romain <romainm@sympatico.ca> wrote:
>LOL! > >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. The pressure at the bottom of the tank depends on the height of the column of water in the tank. The pressure required to pump water up to the elevated tank depends on the height above _ground_ to which it is being pumped. In the situation described (a 55-gal drum elevated some eight feet above the ground) it is necessarily the case that the height of the water column in the drum is *much* less than the height of the drum above ground, and any pump that develops enough pressure to lift water eight feet necessarily develops more than enough pressure to overcome that exerted by the water already in the tank. |
Re: Physics/hydraulics of water and barrel
"Jeepers" <moomesa@INVALIDfnbnet.net> wrote in message news:moomesa-6BB8BB.12550424112004@news-east.newsfeeds.com... > In article <hJ4pd.91466$T02.37417@twister.rdc-kc.rr.com>, > "c" <c@me.org> wrote: > > > My physics is a bit rusty here, but IIRC, the pressure created at the bottom > > opening will be equal to the weight of a water column (which is the area of > > the opening x the height of the water column). This applies whether the > > bottom opening is at the side or on the bottom. A fluid exerts equal > > pressure against all sides of its container that it is in contact with. What > > this means in essence is that it would take slightly less energy to bottom > > fill. Any fluid in a container has some amount of stored energy, The wider > > and shorter the container is, the less energy it will take to fill it. > > > > Also, like the others said, the energy required to top fill will remain > > constant as the barrel fills. For bottom filling, the energy will start out > > slightly less, and end up the same as the barrel reaches full. > > > > Chris > > O.K. my lame-ass attempt at physics argument: > > Isn't part of the column the barrel? The barrel has a bigger column in > it's part, than the hose. So the weight of the water column is GREATLY > larger than the one in the hose going to the top. Less water - less > weight, right? The only thing that matters is the *height* of the column. Sure, the water in the barrel weighs a whole bunch. Most of that weight is supported by the bottom of the barrel, though. Ray Drouillard |
Re: Physics/hydraulics of water and barrel
"Jeepers" <moomesa@INVALIDfnbnet.net> wrote in message news:moomesa-6BB8BB.12550424112004@news-east.newsfeeds.com... > In article <hJ4pd.91466$T02.37417@twister.rdc-kc.rr.com>, > "c" <c@me.org> wrote: > > > My physics is a bit rusty here, but IIRC, the pressure created at the bottom > > opening will be equal to the weight of a water column (which is the area of > > the opening x the height of the water column). This applies whether the > > bottom opening is at the side or on the bottom. A fluid exerts equal > > pressure against all sides of its container that it is in contact with. What > > this means in essence is that it would take slightly less energy to bottom > > fill. Any fluid in a container has some amount of stored energy, The wider > > and shorter the container is, the less energy it will take to fill it. > > > > Also, like the others said, the energy required to top fill will remain > > constant as the barrel fills. For bottom filling, the energy will start out > > slightly less, and end up the same as the barrel reaches full. > > > > Chris > > O.K. my lame-ass attempt at physics argument: > > Isn't part of the column the barrel? The barrel has a bigger column in > it's part, than the hose. So the weight of the water column is GREATLY > larger than the one in the hose going to the top. Less water - less > weight, right? The only thing that matters is the *height* of the column. Sure, the water in the barrel weighs a whole bunch. Most of that weight is supported by the bottom of the barrel, though. Ray Drouillard |
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