One more weird plumbing question; distance of pump from sump

[Anonymous]

In regard to Wazzel and Dan's discussion about wattage and flow rate, the curve (wattage vs GPH) is not linear. Generally, the lower the head pressure (the faster the flow rate), the more energy the pump going to use. The difference between dead flow (totally blocked) and full throttle can be 200% or more (that is, (d-b)/d ). In the usually operating range with low viscosity fluid, Wazzel's statement is accurate.

 

[Anonymous]

Just to add to what GoM said. The frictional losses are a function of the velosity squared. I agree that the best bang for the buck would be to up size the piping back to the tank.

Any idea how much bang we are talking about?

For example 50 gpm which is 3000 gph will have 16 ft of losses per 100 ft of run in 1.5" pipe and 4.7 ft of losses in 2" pipe.

 

[Anonymous]

Not excatelly true. The energy needed to run the pump is a function of several things. Alot depends on the impeller type. The motor will spin at roughly the same speed over the entire operation range of the pump and the difference will not be enough to mater. The equation is

Well I'm no expert. When my tank was delivered short one drain hole, I called Sequence to see if it would be more economical to purchase a smaller pump since mine had to be restrained so much. They said that the difference was considerable, and with the pump dialed back it would be using no more power than their smallest pump going full bore.

Dan, I was not trying to make a fuss. I use to work for an undustrial pump manufacturer and had to deal with this stuff quite often.

 

[Anonymous]

I think we have some confusion. If the net distance from the sump back to the tank remains unchanged because you just moved the pump 6' further away from the sump and 6' closer to the tank, then you are correct that you will not reduce the overall frictional loss of the water traveling through the return plumbing. This would be a waste of effort.

IF. however, you are able to eliminate 6' of the total return run because you, for example, can move the sump closer to the tank or are now hooking up the plumbing to a side of the sump that is closer to the tank, then yes, you will have a net reduction in frictional losses.

The second paragraph is closer to the truth. The question is, by eliminating the 6', how much of a change in flow is to be expected.

Here is a diagram that will hopefully eliminate most confusion.
The top is as it is now.
The second two are possible changes.

This is fun! Thanks guys.

 

[Anonymous]

You want to place the pump as close to the sump as possible, so the second diagram is what I feel is the best.

 

[Anonymous]

Going from #1 to #2 will help. Their is probably minimal, if any, difference between #2 and #3. Increasing the size of the plumbing will also help. As to how much, it depends - the others have already adrressed this issue.

 

[dizzy]

The goal is to get more flow with existing equipment, so I don't have to spend much money.

Righty have you considered using an eductor? Seems like you have plenty of flow down to the sump to accomplish any type of desired filtration there. An eductor on the return nozzle just increases the flow there in the tank where it is actually needed. If I was you I would at least consider this option before I made any major changes to the plumbing lines. It is truly amazing how cost effective and efficient eductors can be.
Mitch

 

[Anonymous]

I agree with GoM that going from 1 to 2 will help while 2 and 3 are pretty much the same.

 

[hillbilly]

If you up the outflow pipe size to 2" and tee off the outflow and create a long loop, then manifold off the longest part of the loop, you will notice a big difference in pressure. This is an old landscape irrigation trick that also works on aquariums!

 

[Anonymous]

Mitch,

Thanks! I had no idea the penductors were available. I will order one tomorrow and see how it works! Less than 4 inches!

Thanks again everyone!
I had another idea for moving my pump closer to the show tank. I could have the current sump feed, with a gravity drain, another sump closer to the show tank and have the pump pump from there. All I would have then is the simple rise for head pressure. This may be the easiest way to go. Anyone have any thoughts?

 

[Anonymous]

That would work. Just make sure the connecting pipe is oversized or put two lines.

 

[dizzy]

Mitch,

Thanks! I had no idea the penductors were available. I will order one tomorrow and see how it works! Less than 4 inches!

Righty you won't be sorry. I got in a dozen and have been hard selling them to some of my best customers. They make me look like a genius, as everyone is impressed with how well they work. 8) Richard Harker made it sound like a better variety of sizes was on the way. While shorter ones might not achieve 5x, even an improvement of 3x for the same energy consumption has merit. Look for these to become all the rage in the future. The average handyman could actually make one without too much trouble.
Mitch

 

[Anonymous]

"penductor"? "eductor"? What the heck are you guys talking about?

 

[Anonymous]

Mitch,

I did some reading and some people have been saying that the 'ductors shouldn't be used on an Ampmaster3K (not to mention one like mine that is pumping against a bunch of head) and that they shouldn't be used with sea swirls (what I have). Do you have any experience or advice?

GoM,

http://www.kthsales.com/website/Misc/he ... siasts.htm

They are used for mixing fluids. You put in on the tank side of the return and they circulate more water than is coming out of the pump. Its magic. The only drawback is they are kind of big - but the penductor is only about 3.5 inches. I am gonna order one in about 15 minutes cause they are only 25 bucks and I wannna see.

Wazzel,

Thanks for all the info. I would either use two 1.5 inch lines (because I have most of the parts) or go with something bigger. I did just realize that to do this I would also have to move my top off float switches to the 'new' sump, but I don't think that is too much of a big deal. Actually moving all the top off stuff to the 'new' sump might free up some good, usable space under the house!

:mrgreen:

 

[dizzy]

Mitch,

I did some reading and some people have been saying that the 'ductors shouldn't be used on an Ampmaster3K (not to mention one like mine that is pumping against a bunch of head) and that they shouldn't be used with sea swirls (what I have). Do you have any experience or advice?

My experience with eductors has been very positive. I am using an Iwaki 70RLT for the return pump however. I also have a tee in the line and some of the output is tapped off to feed a skimmer. I'm not going to suggest that I didn't get lucky in matching the flow to Sea Swirl and eductor size, but I will tell you the increase in performance is unimpeachable. You can see the vast improvement of volume with the eye, and by putting your hand in front of the output with both the supplied Sea Swirl nozzle and the eductor, in turn. What is their reason for not using the eductor with the Sea Swirl? I say give it a try and see what happens.
Mitch

 

[Anonymous]

They said something about the ss not being able to take the back pressure.
The KTHsales site says:

What about other the other devices on the discharge of my pump - filter, strainers, Sea Swirls?  The water will need to be restricted through these other devices to allow pressure for the eductors.  Use control (ball) valves to provide the additional backpressure that will be required to provide adequate pressure for the eductors. 

 

[Anonymous]

Mitch,

I did some reading and some people have been saying that the 'ductors shouldn't be used on an Ampmaster3K (not to mention one like mine that is pumping against a bunch of head) and that they shouldn't be used with sea swirls (what I have). Do you have any experience or advice?

They require a significant amount of pressure (10-30 psi) to operate, and may give the pumps seal problems. Make sure your pump is pressure-rated before you use one!

They are used for mixing fluids. You put in on the tank side of the return and they circulate more water than is coming out of the pump. Its magic.

Basically a venturi/carburetor/beckett sort of thing. Bernoulli's principle and all that.

Some good advice in this thread!

 

[Anonymous]

I ordered some penductors today. The guy said they should work with my pump - they increase pressure in the line, and in my 1.5 inch line I currently have little pressure. He also suggested that I run two to take advantage of the pressure in the line.
I will prolly be selling them soon, because I think they will be too big for my tank.

 

[dizzy]

They require a significant amount of pressure (10-30 psi) to operate, and may give the pumps seal problems. Make sure your pump is pressure-rated before you use one!

How is this any different than putting a valve in the return line to slow down the flow a bit? I was always told to never starve a pump for water, but restricting the output was ok. If what your saying is true then we should never use valves in the return lines unless we are using pressure pumps. No?
Mitch

 

[Anonymous]

They require a significant amount of pressure (10-30 psi) to operate, and may give the pumps seal problems. Make sure your pump is pressure-rated before you use one!

How is this any different than putting a valve in the return line to slow down the flow a bit? I was always told to never starve a pump for water, but restricting the output was ok. If what your saying is true then we should never use valves in the return lines unless we are using pressure pumps. No?
Mitch

I've seen lots of pump seal problems from backpressure, especially in larger pumps.