Bean Overflow Layout - Critique please

[sleepydoc]

I'm in the final planning stages of my coast-to-coast Beananimal overflow conversion. Below is my tentative plumbing layout for the overflow.

- Goal flow: 1000 GPH
- Bulkheads: 1", 45 mm/1.75" hole diameter
- Horizontal spacing tbd depending on sump layout
- Elbows and external plumbing: 1.25"
- I estimate the drop from the top of the weir to the water level in the overflow will be about 1.5"; should be pretty quiet
- Total width: 48", approx 0.25" depth coming over the overflow
- 0.75" between bottom of downturned Elbows & bottom of overflow

Does anyone see any obvious issues? The main question I have is how much height to allow above the upturned dry emergency elbow. Currently it's about ⅝" to the bottom of the frame and just over 1" to the top edge of the frame/tank. Is this adequate, of should I allow more room. I can easily trim a bit off of the top of the upturned elbow and/or drop the depth of the entire overflow to accommodate more emergency depth if needed.

Also, from those who have experience - is ¾" enough space between the elbow and the vertical overflow glass, or is 1" a safer spacing?

 

[uncleof6]

:debi:You are up too high. The inlet to the dry emergency should come out right around the top of the weir. You used your own measurements, not the ones I have provided time and time again. :deadhorse1:

The leak point is the seam at the bottom of the lip on the inside trim. You don't by design want water up that high. The dry emergency flows during start up, assuming the rest is set up right. That ~inch above the inlet to the to the lip, is a safety buffer.

I modified it from the earlier dimensions to pull the dry emergency down lower in the overflow. (For 1" elbows only.) For 1.25" elbows the whole shooting match needs to be lower.

On the 3/4" space below the elbows. The cross-sectional area of the pipe is ~1.23in², the area of the 3/4"space below is ~5.4in². That is more than enough. Why 3/4"? So you have a little room under the elbow to work on it with it still in place...

This is for 1" elbows, with 1.25" elbows, you want to drop the holes down some.

 

[Mrramsey]

I will add that 1.25" pipe will yield quite a lot of bubbles out of the open channel past 800gph. I don't know it 1.5 would reduce it or not must saying. It will certainly flow 1000gph but you will have a lot of bubbles.

 

[uncleof6]

It will depend on the flow through the open channel. If the open channel (1" pipe) is more than 1/4 full of water you will start getting bubbles. On the standard system, Bean used 1.25" elbows, 1" bulkheads, and 1.5" pipe. A 1" open channel makes it more difficult to keep the system bubble free. Siphon should, regardless of size/flow rate, be bubble free, unless you did not seal up (glue/sealant) the joins.

 

[sleepydoc]

:debi:You are up too high. The inlet to the dry emergency should come out right around the top of the weir. You used your own measurements, not the ones I have provided time and time again. :deadhorse1:

Thought I did!

The leak point is the seam at the bottom of the lip on the inside trim. You don't by design want water up that high. The dry emergency flows during start up, assuming the rest is set up right. That ~inch above the inlet to the to the lip, is a safety buffer.

That's the part I was missing - it either wasn't in the posts that I read, or I overlooked it. I honestly don't like making you re-post things, believe it or not! (edit - looking at your diagram again I think I just didn't realize that the 1" you have labeled was intended to be the distance to the top of the upturned elbow)

Fortunately it's easy to alter things on Sketchup...

Attempt #2 is below. Am I understanding you correctly that you want an inch between the top of the dry emergency and the lip of the frame? This puts the drop from the top of the overflow to the expected water level about 1.5 - 2"

 

[sleepydoc]

... one can also bring the top of the upturned elbow down by trimming some off the top/vertical portion. This will also slightly reduce the head of water that occurs on startup, giving less pressure to purge air from the siphon line. Will this be an issue?

The only reason to do this would be to reduce the height of the waterfall over the weir and any associated noise.

 

[AdamPLawrence]

:debi:You are up too high. The inlet to the dry emergency should come out right around the top of the weir. You used your own measurements, not the ones I have provided time and time again. :deadhorse1:

Try again...

 

[Mrramsey]

It will depend on the flow through the open channel. If the open channel (1" pipe) is more than 1/4 full of water you will start getting bubbles. On the standard system, Bean used 1.25" elbows, 1" bulkheads, and 1.5" pipe. A 1" open channel makes it more difficult to keep the system bubble free. Siphon should, regardless of size/flow rate, be bubble free, unless you did not seal up (glue/sealant) the joins.

Agreed... My system is 1.25" elbows, 1" bulkheads, and 1.25" pipe. When I would run at higher rates 8-900gph the bubbles in the open channel got to be excessive and caused additional salt creep in the sump. The only reason I brought it up was because SleepyDoc stated 1.25" pipe with a goal of 1000gph. If I ever redo my pipe I will up to 1.5" for sure. the cost difference was negligible.

 

[asudavew]

Get street elbows to save space and make sure you will be able to fit your hand inside the overflow box. You need enough room to get your hand or a net inside and you need to be able remove the elbows.

 

[sleepydoc]

Try again...

Adam - With the 2nd configuration, the top of the upturned elbow is about 3/8" above the edge of the weir. This still leaves 1" below the lip of the frame. Since the only time the dry standpipe is in use is transiently during startup or when there is a malfunction with the other 2 standpipes, it shouldn't routinely affect the function of the overflow. Ultimately does this matter? I can certainly drop everything down 3/8" more, but that adds 3/8" to the water drop over the weir and potentially more noise and splashing. It seems the primary concern would be allowing enough space above the elbow such that the water level never rises above the lip of the frame.

Agreed... My system is 1.25" elbows, 1" bulkheads, and 1.25" pipe. When I would run at higher rates 8-900gph the bubbles in the open channel got to be excessive and caused additional salt creep in the sump. The only reason I brought it up was because SleepyDoc stated 1.25" pipe with a goal of 1000gph. If I ever redo my pipe I will up to 1.5" for sure. the cost difference was negligible.

Mike - thanks for the tip. As Uncle mentioned, it should depend on the flow through the open standpipe; are you not able to tune it by opening the gate on the full siphon standpipe a touch to reduce the flow in the open channel?

Get street elbows to save space and make sure you will be able to fit your hand inside the overflow box. You need enough room to get your hand or a net inside and you need to be able remove the elbows.

Unfortunately, reducing street elbows are difficult to find, so I ended up adding a reducing bushing between the elbow and the bulkhead. It does add a bit of space, but only about 1/4", so it's not a huge deal. If I'm really concerned about it I can trim a bit off the elbow and the bushing to eliminate the extra.

 

[Mrramsey]

Adam - With the 2nd configuration, the top of the upturned elbow is about 3/8" above the edge of the weir. This still leaves 1" below the lip of the frame. Since the only time the dry standpipe is in use is transiently during startup or when there is a malfunction with the other 2 standpipes, it shouldn't routinely affect the function of the overflow. Ultimately does this matter? I can certainly drop everything down 3/8" more, but that adds 3/8" to the water drop over the weir and potentially more noise and splashing. It seems the primary concern would be allowing enough space above the elbow such that the water level never rises above the lip of the frame.



Mike - thanks for the tip. As Uncle mentioned, it should depend on the flow through the open standpipe; are you not able to tune it by opening the gate on the full siphon standpipe a touch to reduce the flow in the open channel?



Unfortunately, reducing street elbows are difficult to find, so I ended up adding a reducing bushing between the elbow and the bulkhead. It does add a bit of space, but only about 1/4", so it's not a huge deal. If I'm really concerned about it I can trim a bit off the elbow and the bushing to eliminate the extra.

HI SleepyDoc, I am running my main siphon wide open (long story short) my pump is too big so I have the flow reduced on the return. The open channel is also wide open. I just dialed back the return flow to the tank until the Open channel bubbling was at an acceptable level. This is yielding about 750-800 gph, when I hit the 850-900 mark I start getting a lot of bubbling from the open channel.

I attribute it to using 1.25" on the pipes and not 1.5" with a sanitary tee as well. I haven't found a sanitary tee in 1.25". While the 1.25" pipe will surely handle 1000 gph just fine I suspect you will have the same bubble issues I have,therefore I would plan on 1.5" pipe on the drain side. If I had done this I think I could have pushed a little more flow without bubbles.

Also I made my own 1.25" to 1" street elbows. I found 1.25" to 1" elbows and cut the 1" side down until there was about 1/4" of the glue flange left then glued a short piece of 1" pipe.

I also calculate the flow rate by using the Rectangular Contracted Weir calculator found here - http://irrigation.wsu.edu/Content/Calculators/Water-Measurements/Rectangular-Contracted-Weir.php

Just for grins I just tested again and and calculated between 780 and 960 gpm this is on a 40" weir at ~7/32"-8/32" depth over the weir. So I would estimate ~870 Gpm

 

[uncleof6]

I attribute it to using 1.25" on the pipes and not 1.5" with a sanitary tee as well. I haven't found a sanitary tee in 1.25".

Charlotte Pipe & Foundry, UPC# 611942-03462. (1.25" sani-tee; 03463 is 1.5".)

I think the issue with your bubbles is an adjustment problem. Anything below ~250gph should not cause bubbles in just 1.25" pipe by itself. (This is gross estimate.) The 1" bulkhead throws a monkey wrench in the works, due to some turbulence. There could be a couple reasons that the flow through the open channel is too high which would involve the basic set up of the system.

 

[sleepydoc]

1 1/4" sanitary tees are hard to find -
Menards is the only place I've found them, online only.

Charlotte has them in their catalog, but it seems like nobody carries them. I may upsize the open channel drain just to give the system a wider noise-free range and make it easier to adjust.

Uncle - Will having the upturned elbow slightly (3/8") above the weir cause problems as long as there's a good inch below the tank frame, or am I missing something?

 

[uncleof6]

1 1/4" sanitary tees are hard to find -
Menards is the only place I've found them, online only.

Charlotte has them in their catalog, but it seems like nobody carries them. I may upsize the open channel drain just to give the system a wider noise-free range and make it easier to adjust.

The ells from Menard's are fine, use them. I have to order them as well, albeit in bulk, and Pat over at Aquatic Warehouse (LFS here in SD) has them in most of the time.

Uncle - Will having the upturned elbow slightly (3/8") above the weir cause problems as long as there's a good inch below the tank frame, or am I missing something?

I mocked it up, and got 1/2" above the weir, without moving the holes down. (using spears elbows.) I would run it. I wish it were possible to test run all the different variations that get thrown in, but every single system is going to run different. As long as the system starts easily, we are putting non-rocket science under a micro-scope. A half inch isn't going to make any difference. A 5" waterfall increase might drown out your TV. We certainly don't want to pull out the dial calipers. We want to keep the waterfall height as low as possible, but don't want the holes too high on the glass for safety and too little wiggle room.

With larger elbows, you are going to have a longer waterfall. Elbows are not created equal either. The closer the inlet to the dry emergency gets to the top of the tank, the less "wiggle room" you have. If it drops below the weir, you chance dumping water in it. With a very long weir, and a 2" waterfall, it may be silent; with a shorter weir, that 2" may drive you crazy as the head height behind the weir increases at the same flow rate. Only so much can be done; "ideal" is almost not possible. There is only x amount of room to play with.

I think if we are to reduce "noise" in the overflow with a single parameter, it is going to be the length of the weir. The less head behind the weir, the quieter it will be. This is where the short tiny overflow proponents leave the ship. They are pigeonholing into a low flow rate.

 

[sleepydoc]

Yeah, that's kind of what I'm thinking. I could downsize to 1" ells, but thought the 1.25" ones would reduce the flow density. 1" clearance (plus the extra half if you push it up to the very top) ought to be adequate. The air vent tubing for the open channel pipe will occlude before that anyway, so unless both the siphon and the open channel get completely plugged the system should never get to that point anyway.

I probably have about 500 gph dropping 1.5" over a 17" weir in my sump right now and that's completely silent, so I don't think 1000 gph over a 48" weir should be an issue. I suppose I could angle the vertical piece slightly if I really needed to, but I doubt that will be necessary. I think I'll go ahead and build it as designed and see how it works.

Thanks for all your help.

 

[uncleof6]

Yeah, that's kind of what I'm thinking. I could downsize to 1" ells, but thought the 1.25" ones would reduce the flow density. 1" clearance (plus the extra half if you push it up to the very top) ought to be adequate. The air vent tubing for the open channel pipe will occlude before that anyway, so unless both the siphon and the open channel get completely plugged the system should never get to that point anyway.

I probably have about 500 gph dropping 1.5" over a 17" weir in my sump right now and that's completely silent, so I don't think 1000 gph over a 48" weir should be an issue. I suppose I could angle the vertical piece slightly if I really needed to, but I doubt that will be necessary. I think I'll go ahead and build it as designed and see how it works.

Thanks for all your help.

Well remember, the air vent line inlet needs to be higher than the inlet to the dry emergency. That should be clipped just below the trim lip. If the open channel trips at start up, the siphon won't purge the air out.

 

[sleepydoc]

yup - thanks for the reminder, though. I meant that the vent line would occlude before the water got to the top of the trim.

We had a discussion before about the placement of the vent line. If you place it lower than the dry emergency inlet, the open channel switches over to a siphon and drops the water level in the overflow before the siphon channel has a chance to fully purge the air. I assume that's because the siphon needs a slightly higher head of water to help it purge or because the rapid draining by the open channel acting as an unrestricted siphon sucks the water level down fast & far enough that air gets entrained into the siphon line and the cycle just keeps repeating. I'll have to play a bit when I get my system set up.