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jmvotto
11-07-2014, 10:42 AM
Are impeller pumps strong enough to fill/drain through 1180 in the ski locker to two 250 lb bags in the bow teed off and vented with a CV?

creating my black Friday shopping list:cool:

MLA
11-07-2014, 12:19 PM
It will, but it will slow due to the head pressure.

bergermaister
11-07-2014, 12:27 PM
I'm so tempted, but not even gonna touch that one...

gregski
11-07-2014, 02:12 PM
It will, but it will slow due to the head pressure.

I respectfully disagree. The pump performance will only decrease about 1% due to the head pressure. The Johnson spec is 822 gph @ 0 psi and 810 gph @ 1.4 psi which is 3'3" http://www.pumpvendor.com/media/johnson/Johnson_10-24690_series.pdf User tests confirm that these pumps are not greatly affected by head pressure. Of course, aerator pump performance would be greatly reduced due to the head pressure.

jmvotto
11-07-2014, 03:07 PM
I'm so tempted, but not even gonna touch that one...

Berg, you make me laugh. it usually speeds up due to pressure:o

jmvotto
11-07-2014, 03:09 PM
I respectfully disagree. The pump performance will only decrease about 1% due to the head pressure. The Johnson spec is 822 gph @ 0 psi and 810 gph @ 1.4 psi which is 3'3" http://www.pumpvendor.com/media/johnson/Johnson_10-24690_series.pdf User tests confirm that these pumps are not greatly affected by head pressure. Of course, aerator pump performance would be greatly reduced due to the head pressure.

thank you, I was thinking would just be additional fill time for the extra 500 lbs.

parrothd
11-07-2014, 05:55 PM
That's close to my setup, center bag fills the IBS, the vent is connected to the IBS with a 1 way valve...

moombadaze
11-08-2014, 08:46 AM
thank you, I was thinking would just be additional fill time for the extra 500 lbs.

figure a xtra 5 minutes to fill the xtra 500lbs

jmvotto
11-08-2014, 09:44 AM
Plenty of time at the end if the dock to fill the cooler with beer...
:cool:

MLA
11-09-2014, 02:09 PM
I respectfully disagree. The pump performance will only decrease about 1% due to the head pressure. The Johnson spec is 822 gph @ 0 psi and 810 gph @ 1.4 psi which is 3'3" http://www.pumpvendor.com/media/johnson/Johnson_10-24690_series.pdf User tests confirm that these pumps are not greatly affected by head pressure. Of course, aerator pump performance would be greatly reduced due to the head pressure.


An Impeller pump will absolutely be effected. Im not talking about a 3ft lift from the sac to the pump, but talking about pushing through the bottom port of a sac with 1K+ water in it, forcing the over flow into another sac thats located a few feet away and on a higher plane. This is based on actual experience, not printed specs. As stated, yes, it will work, but it will slow greatly, once the belly sac is filled. So if a 3'3" 1" OD hose creates 1.4 PSI, what would a 141 gallon sac build?

MLA
11-09-2014, 02:25 PM
An Impeller pump will absolutely be effected. Im not talking about a 3ft lift from the sac to the pump, but talking about pushing through the bottom port of a sac with 1K+ water in it, forcing the over flow into another sac thats located a few feet away and on a higher plane. This is based on actual experience, not printed specs. As stated, yes, it will work, but it will slow greatly, once the belly sac is filled. So if a 3'3" 1" OD hose creates 1.4 PSI, what would a 141 gallon sac build?

To add another layer, the OP is looking to Y that vent flow into two sacs. These sacs will also need to be filled through the bottom, in order to gravity drain back into the belly sac. The head pressure will continue to grow as those sacs fill.

jmvotto
11-09-2014, 08:10 PM
The 1180 sac goes all the way to the bow so I was going to tee it off at the top, not sure if that will drain properly or if the cv will work correctly or not


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MLA
11-09-2014, 09:23 PM
The 1180 sac goes all the way to the bow so I was going to tee it off at the top, not sure if that will drain properly or if the cv will work correctly or not


Sent from my iPhone using Tapatalk

As long as the 2 supplementary sacs are higher and there is a fee flowing hose from the bottom of those two sac, to the top of belly sac, they will drain. A check valve in their vent lines will aid in the drain efficiency.

gregski
11-11-2014, 08:08 PM
An Impeller pump will absolutely be effected. Im not talking about a 3ft lift from the sac to the pump, but talking about pushing through the bottom port of a sac with 1K+ water in it, forcing the over flow into another sac thats located a few feet away and on a higher plane. This is based on actual experience, not printed specs. As stated, yes, it will work, but it will slow greatly, once the belly sac is filled. So if a 3'3" 1" OD hose creates 1.4 PSI, what would a 141 gallon sac build?
No, the head loss is due to the 3'3" vertical column of water not the hose. It doesn't matter how big the sack is, only how tall. The 1100# fat sack is 2' tall (24"x50" LxW) which when full, puts 0.87psi head pressure on the pump (or anywhere on the bottom of the sack). A 4400# fat sack that were 2' tall but 48"x100" (same height but bigger footprint) would put exactly the same head pressure on the pump 0.87psi when full. If you connect a 2' piece of 1" hose to the pump and hold it straight up, it would also be 0.87psi when full of water.

This isn't always intuitive. 4000# of water could generate less pressure than an ounce of soda in a drinking straw. It only depends on vertical height. So you're question about how much pressure a 141 gallon sack builds is impossible to answer with knowing the physical dimensions.


So if we assume that the vertical distance from the pump to the top of the sack is 2" and we used 10' of hose with 2.6psi/100ft (A 1" PVC pipe flowing at 10gpm has about 2.6psi/100ft of pressure friction head loss), that would be 0.26psi due to the hose and 0.86psi due to the vertical water column for a total of 1.12 psi. Back to our spec, we know we lose 1.5% in flow per 1.4psi in head. So, I estimated the net effect would be around 1%.

Put another way: If you are mounting a pump at a given height and you want to pump water up to a bow sack which is 2' higher than the outlet of the pump, then the pump flow will be exactly the same whether you pump the water up directly with a hose, or if you go up through any size sack that is 2' tall.

To make the point I've neglected the friction losses due to the extra couplings which is real: a 1" 90 elbow has loss equivalent to about 5' of pipe. So if this setup requires 2 extra 90 degree couplings in the pipe, that would be an additional 0.26psi of head.

There are plenty of tests (and physics) which confirm that impeller pumps do in fact perform this way. They don't lose significant flow as pressure increases. However, they do draw more power to keep turning as pressure increases. On the flip side, aerator pumps lose flow but draw the same power as pressure increases. This is not my opinion, it's just the nature of the pump design.

Of course, filling a 1100 sack and then a bow sack will take longer than filling both at the same time with two pumps. But to the answer to the OP's question is: yes, an impeller pump has the "strength" to fill a bow sack in this configuration - and is a good choice for the application.

gregski
11-11-2014, 08:14 PM
As long as the 2 supplementary sacs are higher and there is a fee flowing hose from the bottom of those two sac, to the top of belly sac, they will drain. A check valve in their vent lines will aid in the drain efficiency.

Yup. And I'll add that ours drains perfectly well without a check valve. The sacks even collapse pretty well (but not suctioned like a raisin). If the fill/drain port is the low spot (underway the bow is tipped up) I would recommend starting with an open vent, unless your design needs a check valve for other reasons.

MLA
11-11-2014, 08:32 PM
No, the head loss is due to the 3'3" vertical column of water not the hose. It doesn't matter how big the sack is, only how tall. The 1100# fat sack is 2' tall (24"x50" LxW) which when full, puts 0.87psi head pressure on the pump (or anywhere on the bottom of the sack). A 4400# fat sack that were 2' tall but 48"x100" (same height but bigger footprint) would put exactly the same head pressure on the pump 0.87psi when full. If you connect a 2' piece of 1" hose to the pump and hold it straight up, it would also be 0.87psi when full of water.

This isn't always intuitive. 4000# of water could generate less pressure than an ounce of soda in a drinking straw. It only depends on vertical height. So you're question about how much pressure a 141 gallon sack builds is impossible to answer with knowing the physical dimensions.


So if we assume that the vertical distance from the pump to the top of the sack is 2" and we used 10' of hose with 2.6psi/100ft (A 1" PVC pipe flowing at 10gpm has about 2.6psi/100ft of pressure friction head loss), that would be 0.26psi due to the hose and 0.86psi due to the vertical water column for a total of 1.12 psi. Back to our spec, we know we lose 1.5% in flow per 1.4psi in head. So, I estimated the net effect would be around 1%.

Put another way: If you are mounting a pump at a given height and you want to pump water up to a bow sack which is 2' higher than the outlet of the pump, then the pump flow will be exactly the same whether you pump the water up directly with a hose, or if you go up through any size sack that is 2' tall.

To make the point I've neglected the friction losses due to the extra couplings which is real: a 1" 90 elbow has loss equivalent to about 5' of pipe. So if this setup requires 2 extra 90 degree couplings in the pipe, that would be an additional 0.26psi of head.

There are plenty of tests (and physics) which confirm that impeller pumps do in fact perform this way. They don't lose significant flow as pressure increases. However, they do draw more power to keep turning as pressure increases. On the flip side, aerator pumps lose flow but draw the same power as pressure increases. This is not my opinion, it's just the nature of the pump design.

Of course, filling a 1100 sack and then a bow sack will take longer than filling both at the same time with two pumps. But to the answer to the OP's question is: yes, an impeller pump has the "strength" to fill a bow sack in this configuration - and is a good choice for the application.

Since sac height matters to your calculations, the 1180 Gravity Games sac is 88L x 19H x 19W. Once that sac is filled, the rate of flow to fill those two 250 lb sac, will be slower than if the OP was filling a single 1680 lb sac.

bergermaister
11-11-2014, 08:39 PM
http://www.databreachwatch.org/wp-content/uploads/2013/11/REALLY_SNL_AIGflv.jpg

gregski
11-11-2014, 09:04 PM
Since sac height matters to your calculations, the 1180 Gravity Games sac is 88L x 19H x 19W. Once that sac is filled, the rate of flow to fill those two 250 lb sac, will be slower than if the OP was filling a single 1680 lb sac.

Nope. You're missing the key concept here. If the 1180 sack is 2' tall and the 250's are 1' tall (I assume they are side by side) and are stacked on top of the 1180. Then the pump performance will be exactly the same as if you filled a 1680lb sack that were 3' tall. (assuming that dimensions of the 1680 sack are the same as an 1180 with two 250s on top)

This statement is true about both impeller and aerator pumps.

gregski
11-11-2014, 09:37 PM
Here's a quick sketch:
21049

If the same pump is used in each case, containers A and B will fill in the same amount of time.

In fact, container A would fill faster than B. Exactly the opposite of what seems natural. The reason? In both cases the vertical head is the same. But there is more friction loss going to container B because of the pipe. The pump A is effectively connected to A with such a huge diameter pipe that it has no friction loss at all.

MLA
11-12-2014, 10:03 AM
Greg,

You seem to have agreed with me, that it will work, but a page and a half to prove it wont slow down? I am not going to argue with your math or theories. In doing ballast system for 8 years, ive seen what ive seen, hard to dispute that. Lots of things look good on paper, but just dont work out as planned when put to a real world application.

jmvotto,

I am not trying to talk you out of proceeding with your plan, just wanted to warn you, that it will be slow.

gregski
11-12-2014, 10:43 AM
MLA,

Sorry, but I don't agree with you. The setup that jmvotto describes won't be slower. It may seem slow because you have to wait for the first sack to fill before the second one fills. Running two pumps would of course be faster but only because you'd be filling both sacks at the same time.

jmvotto
11-12-2014, 12:42 PM
Thanks for all you opinions. I did not want this to turn and audio thread LOL
But it looks like it should work fine the way I want with the fill time around 17 minutes. I will let everyone know in the spring if theory become reality. if not another pump can be purchased for faster fill and drain times.

wolfeman131
11-12-2014, 03:48 PM
why would you measure fill time in minutes and not beers?

bergermaister
11-12-2014, 04:05 PM
Good point. I'd probably have to pee at least twice drinking that long for the ballast to fill.

jmvotto
11-12-2014, 08:07 PM
Depends if I'm drinking ultras or sam Adam summer Ale. With the later I may not be able to surf at all after that fill time.��

beat taco
11-12-2014, 11:02 PM
I just wired my pumps so the get 24v and they are twice as fast!

Boonejeepin
11-12-2014, 11:09 PM
I just wired my pumps so the get 24v and they are twice as fast!

Can they handle 24v?

jmvotto
11-12-2014, 11:29 PM
the Johnson pumps can be wired 12 or 24 , but the jabsco are 12v only