Silent and Failsafe Overflow System

[JTL]

JTL - Airline tube for the emergency drain???? Did you mean open?

Nope, as I understand it. The open drain is just that, open. The emergency drain is a full siphon that kicks in when the airline tube can no longer get air.

 

[uncleof6]

Nope, as I understand it. The open drain is just that, open. The emergency drain is a full siphon that kicks in when the airline tube can no longer get air.

Hummm, alrighty then. But why you gotta do this when I only got one hand to type?


You have three standpipes. A siphon, sealed w/valve to adjust water height in over flow. Open channel is a durso type standpipe.. with an airline looped back into the overflow. The third standpipe is the dry emergency, that is the one with the upturned elbow.

Now that the nomenclature is straightened out let's try this again.

 

[JTL]

I stand corrected, but someone needs to change the nomenclature to suit my definitions. What I did is raise the "dry emergency" because it wasn't so dry but it was open and raised the airline tube on the "open channel" which is probably about the same as raising the intake since it raises the full siphon water level. Anyway is appears to work and I appreciate the help.

 

[BeanAnimal]

The emergency drain has no air intake, it is set higher than the other two standpipes and will kick in when the water level is too high. It is dry otherwise.

The open channel standpipe is the one with the air intake. The intake is set so that the open channel becomes a siphon in the event that system becomes unbalanced. This allows the open channel standpipe to operate silently during normal circumstances but become a full siphon (thus flushing the overflow box) during abnormal operation and/or system startup.

The emergency standpipe is the fail-safe. Systems with low flow may never see it kick in, even with a fully plugged siphon and partialy blocked open channel. However, those with high flow systems may see it kick in even during system startup.

Again (for those who did not read the thread or my website) the reason for the 3rd standpipe is for fail-safe operation in ANY environment. The system was published as a simple one-size-almost-fits-all solution. The goal was to publish a simple design that could be easily leveraged to any size tank and therefore be easily supported, explained and passed along. This was chosen over publishing 2 or 3 different standpipe topologies and confusing "flow rate" guidelines that do nothing but make things far more confusing and create a vastly larger number of questions.

This setup greatly differs from typical standpipe configurations, be they "durso" or "herbie" style setups. The fail-safe air intake and fail-safe dry standpipe virtually eliminate the possibility of system overflow. At the same time, the useable range of flow rates, ease of system adjustment, self tuning and stability is a vast improvement over other designs. While some aquarists may not need or desire the benefits of the system, they were a MUST HAVE for me.

 

[BeanAnimal]

I stand corrected, but someone needs to change the nomenclature to suit my definitions. What I did is raise the "dry emergency" because it wasn't so dry but it was open and raised the airline tube on the "open channel" which is probably about the same as raising the intake since it raises the full siphon water level. Anyway is appears to work and I appreciate the help.

Raising the air intake and raising the weir height are two different things.

Raising the weir height of the open channel in relation to that of the siphon standpipe forces water into the siphon standpipe before it gets to the open chennel. This can aid in forcing the siphon to start, but in most cases is not needed if the standpipes are terminated properly just below the working water level of the sump.

Raising the air intake simply changes the "fail-safe" level in which the open channel standpipe turns into a full siphon. The air intake needs to be set above the normal operating level of the overflow box but below the point where the system will flood the floor. If it is kicking in before the siphon takes hold, and preventing the siphon from ever reaching a balance, then it is too low

 

[JTL]

I clearly had this setup out of adjustment no wonder it didn't work properly. The main problem was the emergency drain being too low. Water flowed into it before the main drain established a siphon and the open channel also kicked in before the main drain. Thanks.

 

[uncleof6]

The emergency drain has no air intake, it is set higher than the other two standpipes and will kick in when the water level is too high. It is dry otherwise.

The open channel standpipe is the one with the air intake. The intake is set so that the open channel becomes a siphon BEFORE the emergency standpipe kicks in. This allows the open channel standpipe to operate silently during normal circumstances but become a full siphon (thus flushing the overflow box) during abnormal operation and/or system startup.

The emergency standpipe is the fail-safe. Systems with low flow may never see it kic in, even with a fully plugged siphon and partialy blocked open channel. However, those with high flow systems may see it kick in even during system startup.

Again (for those who did not read the thread or my website) the reason for the 3rd standpipe is for fail-safe operation in ANY environment. The system was published as a simple one-size-almost-fits-all solution. The goal was to publish a simple design that could be easily leveraged to any size tank and therefore be easily supported, explained and passed along. This was chosen over publishing 2 or 3 different standpipe topologies and confusing "flow rate" guidelines that do nothing but make things far more confusing and create a vastly larger number of questions.

This setup greatly differs from typical standpipe configurations, be they "durso" or "herbie" style setups. The fail-safe air intake and fail-safe dry standpipe virtually eliminate the possibility of system overflow. At the same time, the useable range of flow rates, ease of system adjustment, self tuning and stability is a vast improvement over other designs. While some aquarists may not need or desire the benefits of the system, they were a MUST HAVE for me.

I gotta a bone to pick with ya bean-- seems there is a contradiction here:

"Failsafe:
The setup has (2) failsafe features.

1) The Emergency (left) standpipe is set at a level slightly higher than the normal operating height of the overflow box. It is simply an up-turned elbow or strainer. If the water level rises above the normal operating level then it will flow down the Emergency (left) standpipe. This standpipe is also airtight. If the water level rises high enough the standpipe will begin to siphon and flush the overflow box.

NOTE:The Emergency (left) standpipe will also kick in during system startup. It takes a few moments for the air to be purged from the Siphon (middle) standpipe, during which time the water level in the overflow box may run high and into the Emergency (left) standpipe.

2) The Open Channel (right) standpipe is equipped with an airline that is attached in the overflow box. If the water level rises to the critical point of overflow and the Emergency (left) standpipe can not handle the flow (say due to blockage from algea or something) then the water will cover the inlet of the airline. The flooded air intake will in effect convert the Open Channel (right) standpipe into a full siphon standpipe, allowing it to handle much more flow. This will flush the overflow box and prevent flooding." (from page one of the original thread)

This would say that the dry emergency should kick in first, and the airline trigger would trip as the last resort....have you changed the system logic? If so, there are a lot of systems I gotta go back and change-----

 

[BeanAnimal]

Jim,

I have edited the posts to reflect that advice that has been passed on since the page and thread were first posted. In my haste to answer the question and eat my dinner, I posted without proofreading.

The system will operate either way and I have found that a lot of folks set the airline height somewhere above the normal operating level. That may be above or below the emergency standpipe intake.

Both the airline and the dry standpipe are fail-safe features. That said, it would be preferable to keep the airline as the final fail-safe for several reasons, but mostly to avoid the issue JTL was having getting the siphon to start.

Thank you for pointing out the inconsistent advice... ambiguity creates questions and confusion and that is contrary to the goal of this design.

 

[RocketSurgeon]

I only thought I was confused before all this came about, and now I know I am. I guess it's a good thing I haven't finished it all yet.

 

[uncleof6]

Don't worry--you will be fine. Bean has been incredibly clear and concise in the design and operating parameters for this system. Whenever there is confusion go to his website (or page one of the original thread). It is all there. The system can operate with a couple mods, but always "default" to the info in those two places.

Jim

 

[reev]

JTL, we obviously named the pipes differently .
I used the name "siphon" for the closed pipe, the one with the valve through which there is no air flowing. I used the name "open channel" for the pipe that takes the overflow and has the airline tubing to allow air to be sucked in for silent operation. The name "emergency" is for the pipe whose opening is oriented upwards and that takes water in only when the system starts or when one of the other pipes is clogged.

So my recommendation was indeed to lower the pipe with the airline, to increase the resistance of the flow through it. Also by keeping the closed/siphon pipe bottom level right under the sump water level, its resistance is that the min level. Then, the water from overflow box will have an easier time to push the air down in the closed pipe and create the siphon/suction in it.

 

[JTL]

Don't worry--you will be fine. Bean has been incredibly clear and concise in the design and operating parameters for this system. Whenever there is confusion go to his website (or page one of the original thread). It is all there. The system can operate with a couple mods, but always "default" to the info in those two places.

Jim

I gotta a bone to pick with ya bean-- seems there is a contradiction here:

Kinda funny, but we get the point.:lol2:

 

[uncleof6]

JTL, we obviously named the pipes differently .
I used the name "siphon" for the closed pipe, the one with the valve through which there is no air flowing. I used the name "open channel" for the pipe that takes the overflow and has the airline tubing to allow air to be sucked in for silent operation. The name "emergency" is for the pipe whose opening is oriented upwards and that takes water in only when the system starts or when one of the other pipes is clogged.

So my recommendation was indeed to lower the pipe with the airline, to increase the resistance of the flow through it. Also by keeping the closed/siphon pipe bottom level right under the sump water level, its resistance is that the min level. Then, the water from overflow box will have an easier time to push the air down in the closed pipe and create the siphon/suction in it.

Well that was clear to me, the first time around which is why i questioned the recommendation. By increasing the back pressure in the open channel, you create the problem you where trying to solve with the siphon, only now the problem will exist in the open channel--if it needs to go to siphon. This is an ill advised course of action. If your siphon was not starting, there is something else wrong with the system. The problem still exists, just the symptom is not showing.

The system works as designed with the pipes terminating just below the sump water level. If it does not function correctly, there was an error in the setup, adjustment-- or both.

Jim

 

[importspeedman]

Hi.
Quick question.
I have 3 bulkheads in my overflow box, two @.75" one at 1.5".
I will be using one of the .75" bulkheads for the siphon. What should I use for my open channel the other .75" or the 1.5".
I kinda think it might be smartest to use the 1.5" for the emergency but I have never used this system before and would like some feedback.
Thanks
Rich

 

[teesquare]

In my plumbing of these systems - I always up size the emergency drain.
T

 

[BeanAnimal]

The problem here is that narrow open channel. You did not mention a flow rate, but the narrow open channel will be prone to turbulant (2 phase) flow where the air mixes with the water and creates a partial siphon.

 

[importspeedman]

Ok cool. I will use the 1.5" for the open channel. I dont have the tank setup yet and dont know what pump (or sump) I will have. The tank I believe is a 140 gallons (72lx15wx30t). I am currently replacing all the bulkheads and they were all sch80 from the previous owner. I did water test it last night and got roughly 1600gph through one .75" with full siphon, with only two 45 degree elbows.

 

[Daimyo68]

Figured this to be the best place to ask this question.

Working on my 125g now and going with an internal/external overflow with the BA setup.

For the outside box, is it best to go with 10mm glass for bottom/sides/back? I am assuming yes with the dimensions I have planned for the box.

Internal box will be using 6mm glass.

(External box will be 54"x5.5"x7", with 3 - 1.5" bulkheads on the bottom pane of glass)

Thanks

 

[reev]

Well that was clear to me, the first time around which is why i questioned the recommendation. By increasing the back pressure in the open channel, you create the problem you where trying to solve with the siphon, only now the problem will exist in the open channel--if it needs to go to siphon. This is an ill advised course of action. If your siphon was not starting, there is something else wrong with the system. The problem still exists, just the symptom is not showing.

The system works as designed with the pipes terminating just below the sump water level. If it does not function correctly, there was an error in the setup, adjustment-- or both.

Jim

Jim, I see your point and it might be something that I did different on my setup: in my case the open channel becomes a siphon before the emergency pipe kicks in, because the top of the airline is lower then the top of the emergency pipe. When both operational pipes were right under the water level, there was not enough pressure from the overflow box to push the air out of the closed pipe. Once I increased the resistance of flow in the open channel by lowering it in the water, there is enough pressure from the top to push the air out of the closed pipe.

Or maybe it works just by luck . All I can tell for sure is that before lowering that pipe in the water, most of the times the siphon didn't form, while now it forms every time in less than 30 seconds.

 

[uncleof6]

Well, I will bet that if you set it up the way it was first described, (changing the trip order by raising the airline,) the system will work the way it is supposed to and eliminate the risk involved with having the pipe that deep in the sump. We just went over that a few posts ago..........

Consistency of design, setup, and adjustment makes it easy to troubleshoot a problem without hands on the system. It limits the possible causes. Siphon does not start up: air leak in the line or terminating too far below sump water level. Not the airline tripping the open channel too soon and/or the dry pipe too low.....or the air leak or the line too deep in the sump and or....... I would test that open channel by shutting off the siphon and dry emergency to make sure it will start a siphon. If it works it works.