Silent and Failsafe Overflow System

[BeanAnimal]

To completely silence the system and ensure that the full siphon of the main drain engages after a power outage the pressure at the ends of the pipe have to be "tuned" or adjusted (relative to one another) in order to minimize noise and "start-up" time. If the pipes are a different diameter it may be more difficult to find the correct setup.

Not really

The deeper the siphon standpipe is submerged into the sump, the harder it will be for it to purge the air at startup.

 

[Dudester]

Thanks Bean, and everyone else! BTW, where does everyone get black sanitary Tee's and fittings? Or are they just painted?

 

[BeanAnimal]

Can you please tell me why tying them together is not worth the effort. I haven't tried it (I think I said that), so I must be missing something in my understanding of plumbing.

Thanks

It is somewhat of a crap shoot. In many cases, the system will function correctly, but in others there will be oscillation between the two siphon pipes. It all depends on the pipe configuration, flow rate and head pressure and where they are tied together.

 

[TheFishMan65]

Thanks, now that you say oscillation I can make up reasons were I can see it might happen (whether it truly would I don't know).

I think the catch if some were were to try this would be to make each side the same in terms of pipe lengths bends, etc.

 

[pandimus]

Thanks Bean, and everyone else! BTW, where does everyone get black sanitary Tee's and fittings? Or are they just painted?

got my black sanitary tees in lowes, they were over by the ball valves. matter of fact they did not have white ones at this particular lowes.

 

[leeit2me]

It is somewhat of a crap shoot. In many cases, the system will function correctly, but in others there will be oscillation between the two siphon pipes. It all depends on the pipe configuration, flow rate and head pressure and where they are tied together.

Would be feasible to use a Y to connect from the E pipe to one of the siphon pipes? I am in the process in starting the plumbing and was dry fitting everything and I had this Y PVC connector and was wondering I can kill two birds with one stone? Would it cause any issues as how it drains?

 

[TheFishMan65]

Assuming E is emergency then yes. This would allow air into the siphon at the Y and it would no longer be a siphon and probably be noisy.

 

[cfsindorf]

If you are putting a CTC overflow box on back side is there a size that works best, 4x4 or 6x6 or....? Or should i put the tank wall inside the tank and just make it deeper? I do not want that box inside the tank. I want a clean back wall. Tank will either be 24x24x24 or 30x30x24.

Thanks

Craig

 

[BeanAnimal]

Craig, in general, as large as you are comfortable working in.

 

[cfsindorf]

thanks

I think I will just add the false wall on the back so from the 0outside its one large box. Drill the holes in the bottom of the tank dont add a box to the outside

 

[BeanAnimal]

Why not use the external box and save room in the tank?

 

[CliftonArbogast]

This was a mistake to make for my second tank. Its too quiet and now I want to retrofit into a running 120! How to do that without all the trouble! HMMMMM. Thanks bean, good plans and great design.

 

[MHG]

Air Tube

Air Tube

A great informative thread but I was searching the thread on the air tube. But I did have a couple of questions...

I have a durso style stand pipe with the tanks standard 3/4 inch return used as an emergency overflow. I piped the new return over the back of the tank...


What is the purpos of the air tube? I understand the air hole in the cap, or the added valve to adjust the air flow, but what does the tube do?


where should the tube go and why?

 

[TheFishMan65]

The end of the tube get placed a little above the emergency. Then if the emergency can not handle the flow the tube will get covered. This will block the air flow to the open channel and convert it to a siphon.

 

[BeanAnimal]

I am not sure if your question is in reference to my build or Durso standpipes in general so I will try to explain from both perspectives in somewhat layman terms. This is all covered on my site and the first page of this thread, but it may be worth repeating.

When water falls through a pipe it can behave in several different ways. If the water volume is not sufficient to fill the pipe and the flow is somewhat smooth (laminar) then the water will cling to the pipe walls. This allows air to be present in the pipe with overall little effect on the way the water flows. As the flow increases (with relation to the area of the pipe) the water will begin to tumble and churn as it drops. In doing so, the water begins to create suction (a pressure drop) above it. If no air is allowed into the pipe, then the flow will begin to form a siphon. That is the "suction" will pull water from the intake pool. The rate of flow is a pure function of the pipe diameter (at is smallest point) and the net drop (head) between the intake pool and discharge pool heights connected to the pipe.

If the pipe has an opening at the top, that same suction that is trying to draw water in, will also draw air in. The air that is drawn in displaces water and therefore decreases the overall flow through the standpipe. As the air mixes with the water it also creates turbulance and the tubulnace also reduces the flow in the standpipe.

A "Durso" functions (or is tuned) by adjusting the amount of air that is allowed to enter the standpipe. Adjusting the amount of air adjusts the amount of water and the amount of turbulance. The idea is to get the "two phase" flow to be stable and quiet. The reality is that for a given standpipe size and height, the range of "quiet and stable" flow that that can be tuned to the standpipe is very small. A side effect is that the the air sucked into the standpipe gets chruned into tiny bubbles and ejected at the discharge.

In my design, the standpipe IS NOT regulated by air. The air volume allowed to enter the standpipe must be sufficient to allow the single phase laminar (water clinging to the pipe walls) flow. The VALVE is NOT needed and there ARE NO ADJUSTMENTS. The Valve only serves as a maintenance tool if needed. The TUBE is part of the fail-safe system. It is connected to the standpipe and curled over and attached just above the normal operating level of the overflow box. If, for any reason, the water rises to this level, the air intake will become blocked with water and seal the standpipe, turning it into a full siphon.

My design does not function as a "Durso" or "Stockman". The references to those designs are from a mechanical standpoint, not a functional standpoint. That is, the purpose of mentioning them was to convey how they are constructed and further to outline how they differ in function.

This fail-safe feature can be used on just about ANY Durso or Stockman standpipe.

Hope that makes sense.

 

[Floyd R Turbo]

I'm having Miracles custom-build a replacement tank for one of my customers. Their acrylic tank cracked due to poor stand construction. So the replacement tank will be a 120 (66 L x 18 W x 24 W) with a tempered notched end and external overflow box. The box will have holes in the bottom for three 1.5" bulkheads, and will look like this:

The circles are (inner to outer) outer pipe diameter, hole in glass, and edge of bulkhead.

I plan to run a Mag 18 or equivalent with a 1.5" return to a plenum so there will be probably 1200-1400 GPH depending on the head feet created by the plenum. So this is obviously way less than the GPH the siphon can handle. What I was planning on doing was downsizing the plumbing below the full siphon bulkhead to 1.25" or even 1" to throttle back the flow. Then in the future, if I swap the pump out for a stronger one, I have the capacity to go up to much higher flow - I would just bump up the plumbing below the siphon bulkhead.

So my question is: will downsizing the plumbing as described cause any issues with the system?

I've read through this entire thread but it was a couple months ago, so forgive me if these questions have been answered several times already...

 

[TheFishMan65]

I don't believe downsizing will cause a problem. I do have a question. Why the triangle shape for the drains? Why not a straight line? I wider box will have more leverage and be more likely to pop off. Now the pipes will be supported (right ?) and the box is the proper thickness and attached correctly (right again ?) so it probably is not a problem. Just curios why that lay out.

Thanks

 

[CJBROWN]

I don't see a problem with that either. I'm running 1" drains and have to close the ball valve more than halfway to run full siphon with about 450gph. As I mentioned in our emails, my eheim 1260 was cut down a bit after plumbing in a chiller on the return line. I run a 1" return and I know the chiller plumbing isn't that big, and there are a few more 90deg turns with it. Still plenty of flow for a 75gl.

The triangle configuration of the bulkheads will provide more room for the standpipe heads, whatever configuration you decide on. I think it looks good.

And I think your flow is plenty for a 120. Sometimes I think people get carried away with moving water with the circulation pump. You don't need all that water running thru the sump. Make up your desired tank circulation with powerheads or a CL system. I installed two of the #3 Sicce Voyagers with their timing controller which alternates them, 1 minute each is how I have it running - works really nicely, great flow. Also assuming one installs a satisfactory skimmer for aeration and removal of suspended organic pollutants. The skimmate from my magus is disgusting. It's like pooh. Probably is!!

I'm having Miracles custom-build a replacement tank for one of my customers. Their acrylic tank cracked due to poor stand construction. So the replacement tank will be a 120 (66 L x 18 W x 24 W) with a tempered notched end and external overflow box. The box will have holes in the bottom for three 1.5" bulkheads, and will look like this:

The circles are (inner to outer) outer pipe diameter, hole in glass, and edge of bulkhead.

I plan to run a Mag 18 or equivalent with a 1.5" return to a plenum so there will be probably 1200-1400 GPH depending on the head feet created by the plenum. So this is obviously way less than the GPH the siphon can handle. What I was planning on doing was downsizing the plumbing below the full siphon bulkhead to 1.25" or even 1" to throttle back the flow. Then in the future, if I swap the pump out for a stronger one, I have the capacity to go up to much higher flow - I would just bump up the plumbing below the siphon bulkhead.

So my question is: will downsizing the plumbing as described cause any issues with the system?

I've read through this entire thread but it was a couple months ago, so forgive me if these questions have been answered several times already...

 

[MHG]

I am not sure if your question is in reference to my build or Durso standpipes in general so I will try to explain from both perspectives in somewhat layman terms. This is all covered on my site and the first page of this thread, but it may be worth repeating.

When water falls through a pipe it can behave in several different ways. If the water volume is not sufficient to fill the pipe and the flow is somewhat smooth (laminar) then the water will cling to the pipe walls. This allows air to be present in the pipe with overall little effect on the way the water flows. As the flow increases (with relation to the area of the pipe) the water will begin to tumble and churn as it drops. In doing so, the water begins to create suction (a pressure drop) above it. If no air is allowed into the pipe, then the flow will begin to form a siphon. That is the "suction" will pull water from the intake pool. The rate of flow is a pure function of the pipe diameter (at is smallest point) and the net drop (head) between the intake pool and discharge pool heights connected to the pipe.

If the pipe has an opening at the top, that same suction that is trying to draw water in, will also draw air in. The air that is drawn in displaces water and therefore decreases the overall flow through the standpipe. As the air mixes with the water it also creates turbulance and the tubulnace also reduces the flow in the standpipe.

A "Durso" functions (or is tuned) by adjusting the amount of air that is allowed to enter the standpipe. Adjusting the amount of air adjusts the amount of water and the amount of turbulance. The idea is to get the "two phase" flow to be stable and quiet. The reality is that for a given standpipe size and height, the range of "quiet and stable" flow that that can be tuned to the standpipe is very small. A side effect is that the the air sucked into the standpipe gets chruned into tiny bubbles and ejected at the discharge.

In my design, the standpipe IS NOT regulated by air. The air volume allowed to enter the standpipe must be sufficient to allow the single phase laminar (water clinging to the pipe walls) flow. The VALVE is NOT needed and there ARE NO ADJUSTMENTS. The Valve only serves as a maintenance tool if needed. The TUBE is part of the fail-safe system. It is connected to the standpipe and curled over and attached just above the normal operating level of the overflow box. If, for any reason, the water rises to this level, the air intake will become blocked with water and seal the standpipe, turning it into a full siphon.

My design does not function as a "Durso" or "Stockman". The references to those designs are from a mechanical standpoint, not a functional standpoint. That is, the purpose of mentioning them was to convey how they are constructed and further to outline how they differ in function.

This fail-safe feature can be used on just about ANY Durso or Stockman standpipe.

Hope that makes sense.

Great...thanks...

 

[pandimus]

So i just wanted to give a couple of pics of my Beananimal overflow, and my overflow box. I didnt go c2c because of my returns but heres a few pics to give you an idea what my overflow looks like.

I also did not go all the way to the trim with overflow box because of the center glass/brace stuff i went down 1/4"

thanks bean.

Oh yeah, also the plumbing pics were pre-glue, i actually added a union to emergency.