Herbie or Bean Animal overflow question

[Adam]

Maybe this will help.

 

[grouper therapy]

anit77;1059215 wrote: We're only talking a few inches over the top of the siphon. This has no real effect in increasing the amount of flow. It's gravity's effect on the water in the pipe that does that. In a vertical drop the longer the pipe the more water is on that pipe. More water = more weight = more flow.

Yes that is somewhat correct. But when your restricting flow with the valve if the bottom of the siphon pipe isn't submerged you're giving the opportunity for air to enter the pipe as the flow is reduced there to the point that air pressure is more than the water pressure. This is hard to explain in text typing on my phone. It's the same principle as the class room experiment with a glass of water and a piece of paper and turning it upside down. It's the air pressure and vacuum that keeps the water in the glass.

anit77;1059322 wrote: You're confusing head pressure for pumps and water weight over an open pipe. Water only weighs 0.036127lbs per cubic inch. So if you have 5" over the top of the siphon pipe there's 2.89 ounces of weight over the entrance of the pipe. If you double the height you still don't even have a quarter pound of pressure. Granted this is a generalization you can see we're not talking much in the over flow box.

No I'm not . The results of my test mentioned above clearly shows there is a difference albeit not large. Head pressure is the same against a pump impeller or that valve. The head pressure increases with depth or height not surface area or weight. That is why a larger pipe does not make a difference in head lose above an impeller. It will actually increase the flow.

Feel free to try you own experiment . I think I will try it tomorrow with 12 " difference and see.

 

[grouper therapy]

http://www.beananimal.com/articles/hydraulics-for-the-aquarist.aspx">http://www.beananimal.com/articles/hydraulics-for-the-aquarist.aspx</a>

Check this calculator out . It explains better than I could ever. The discharge location is considered to be the smallest diameter the water passes through in our case the ball valve most likely. So its placement does impact the flow. Any pipe after the smallest area only acts as a direction of flow

 

[grouper therapy]

anit77;1059327 wrote: Maybe this will help.
https://en.m.wikipedia.org/wiki/Siphon">https://en.m.wikipedia.org/wiki/Siphon</a>[/QUOTE]
Not really but thanks. Actually we are not using the term siphon correctly since there is no lift.. This is a typical drain that we restrict until flooded. I do agree that gravity powers it.

 

[grouper therapy]

In any scenario the distance did make some difference but in none of them did the pipe being submerge make any difference at all. Which was my original question.

 

[squarebob]

So what was the difference in noise between having the outlet submerged or open? I have my Bean submerged about 3/4" and it is noise free. It take about a minute to clear after the return pump is restarted.

 

[grouper therapy]

squarebob;1060025 wrote: So what was the difference in noise between having the outlet submerged or open? I have my Bean submerged about 3/4" and it is noise free. It take about a minute to clear after the return pump is restarted.

Noise wise from basically nothing to like a faucet running. I guess it would depend on the gph as far as noise in or out. Submerged was almost silent.

 

[snowmansnow]

If they aren't submerged you wouldn't get a syphon. That's what makes it so quiet... It isn't a drain .... It's a syphon where the overflows are completely filled with water


So long, and thanks for all the fish.

 

[grouper therapy]

SnowManSnow;1060037 wrote: If they aren't submerged you wouldn't get a syphon. That's what makes it so quiet... It isn't a drain .... It's a syphon where the overflows are completely filled with water


So long, and thanks for all the fish.

Which end? We are referencing the discharge end which does not have to be submerged. Technically if there is no lift of water I don't think it is a siphon.
as defined by Webster (a tube used to convey liquid upwards from a reservoir and then down to a lower level of its own accord. Once the liquid has been forced into the tube, typically by suction or immersion, flow continues unaided.) What I tested was basically a flooded drain.

 

[grouper therapy]

Ok after running a few weeks I came up with some answers. The tube does not have to be submerged to start the flow, it actually starts quicker not submerged as the air purges easier. The noise is the reason to submerge it seems. I placed the gate valve at my sump which is 15' away and a drop of around 3 feet. This made a huge impact on the amount of water the single 3/4" bulkhead could handle. I used no stand pipe on the siphon side in the overflow box. The pipe being slightly submerged did seem to increase the flow albeit ever so slightly. So Seth was right! Mark that on your calendars I also made my own sweeping elbows which really improved the flow to the tank. I haven't measured the flow from the DCT400 pump but the 3/4" bulkhead can handle it all. I will probably upgrade to a 6000 or 8000.

 

[huskerreefatl]

hzheng33;1059205 wrote: for whatever it's worth, this was shares with me from Grant. For clarification, we are talking about the 1/2 inch difference between the water level and the wiers, correct?

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I just re-plumbed my tank and made it exactly like this in the overflow. Before it had a 90 degree elbow point down on the main drain. The new method works nicely but when you shut the system down, there is a loud slurping noise when the water reaches the main drain pipe level and then when you fill it back up, it slurps again until it is completely covered. It is a nice alarm if you didn't intend for it to happen but annoying otherwise. For the other end at the sump, since I bought the trigger emerald sump and it comes with connectors for the drains, all you do is connect to theirs but theirs extends about 6 inches under the water line. The systems seems to work fine though...just the loud slurping from the main drain when draining or filling. Other than that, it is quiet. I have my emergency drain about 1/2" below the weir and let just a trickle of water go in.

 

[huskerreefatl]

grouper therapy;1059284 wrote: Ok guys after several trials with each scenario here are the results
3/4" bulkhead 3/4" thin wall pvc and 3/4" true union ball valve 84" to the top of the waterline in the tank. 72" to the opening in the bulkhead.
time to fill 5 gallon bucket
discharge under water 59,57,61 seconds
discharge out of water 57,56,59 seconds

no pipe after true union valve 58 ,59,60 seconds
Now with a 6" standpipe in bulkhead reducing the distance to the waterline by 50%
e.
discharge under water 68,70,75 seconds
discharge out of water 69,71,74 seconds.

So I deduct the only difference was the taller standpipe in the overflow,which reduced flow around 10-15%
I would like to see how much 18" difference would be.
The discharge under water or out made no difference

Also the difference in height after valve seemed to have very little impact either.

Not related to discharge time but the standpipe in the overflow will prevent as much water draining to your sump since it will drain down to that pipe height and stop.

 

[grouper therapy]

Yeah I know but I'm actually trying to get more to drain down for water changes. My overflow box is only around a gallon anyway. It is an external with a low profile weir on the inside. There is a through wall 2 " bulkhead to the others. My overflow box is hidden in the wall. With the pipe submerged it is totally silent.