Silent and Failsafe Overflow System

[BeanAnimal]

using the gasket on the threaded side of an application with a bulkhead will leak.... maybe not at first but will absolutely leak with any pressure over time.... think about it the threads go through the gasket.... the water will just follow the threads around the bulkhead and through the gasket and leak....this will not create a seal down in the threads

Correct, but if the leak is into the external overflow box, then it is acceptable.

In the illustration above, there would need to be gaskets between the external box and tank. Gaskets between the internal box and tank wall, and flange and internal gasket would be somewhat optional, but advised to slow the leaking of water into the external box during idle times when the return pump is not running.

Ideally the bulkhead would be turned around so that the flange was in the external box, with a gasket and s second gasket would be between the tank and external box. This would prevent water from leaking into the external box during idle times.

That is assuming the "bulkhead" is the device holding both inside and outside boxes on.

 

[bmanzie]

using the gasket on the threaded side of an application with a bulkhead will leak.... maybe not at first but will absolutely leak with any pressure over time.... think about it the threads go through the gasket.... the water will just follow the threads around the bulkhead and through the gasket and leak....this will not create a seal down in the threads

I wasn't intending on putting the gasget on the nut side. I will be placing a gasket between the back outside wall of tank and the outside box. this will limit the water drippage to the inside of the Outside box.

 

[bmanzie]

Correct, but if the leak is into the external overflow box, then it is acceptable.

In the illustration above, there would need to be gaskets between the external box and tank. Gaskets between the internal box and tank wall, and flange and internal gasket would be somewhat optional, but advised to slow the leaking of water into the external box during idle times when the return pump is not running.

Ideally the bulkhead would be turned around so that the flange was in the external box, with a gasket and s second gasket would be between the tank and external box. This would prevent water from leaking into the external box during idle times.

That is assuming the "bulkhead" is the device holding both inside and outside boxes on.

Yes it would be ideal to have the flange side of the bulkhead in the Outside box and is the only way I could do it. I think this will work and will prevent from having an extra two 90's pointing down into the box.
Once it is done I will post an update.
Thank you all for your help.

 

[TheFishMan65]

bmanzie,

I think you have that wrong or maybe I am reading you wrong.. Unless you put a gasket on the flange end of the bulkhead water can get into the threads. Once there the the gasket between the tank and the overflow won't slow any water since it does not interfere with the threads.

 

[mrx66699]

bmanzie,

I think you have that wrong or maybe I am reading you wrong.. Unless you put a gasket on the flange end of the bulkhead water can get into the threads. Once there the the gasket between the tank and the overflow won't slow any water since it does not interfere with the threads.

I think your correct. If the flange side is inside the outside box and is gasketed then water will not leak outside of the outside box back in between the DT and outside box but will still leak from the other side in between the DT and the box coming from the tank. Even when you put an additional gasket on the outside of the DT between the DT and the outside box water will leak following the threads from inside the overflow box in the DT. It will not leak into the outside box but will leak between the outside box and the DT onto the floor.

Bill if you are going to run the overflow in the DT straight into the outside box then you would use a set of uniseals on the DT with the pipe on the inside running into the glass holes style overflow box the seal would be between the DT and the overflow box inside put the 1.5 pipe though it and a set of uniseals on the outside box with the 1.5 pipe running through them into the outside box. This would create seals on the inside DT and seals on the outside box with the pipe running through them. You dont need to worry about a seal between the inside of the DT and the overflow box.

Bean what do you think am I correct on this.

No matter what way you place the bulkhead flange on the outside or flange on the inside you will still have water leaking from the threaded side between the DT and the outside box. Bulkheads are not intended for applications of more than one wall. You will eventually have leakage between the walls from the threaded side when liquid and pressure are on both sides. They will work to an extent but its going to leak following around the threads. It wont matter where you place the gaskets as the threads go through the gaskets.

 

[bmanzie]

Just to clear things up I want everyone to know that I am not arguing their thoughts but simply questioning for the purposes of learning whether it be on my side or yours....
With that being said, my thoughts (whether right or wrong) are, the flange side has a flat surface pushing on a gasket which is pushing on another flat surface. This pressure on the gasket creates a seal. No water seeping through the gasket. Having the back wall of my tank then a gasket and then the back side of the outer box creates that same effect. No water seeping in or out because the gasket has created a seal between to two flat surfaces. the third gasket inside the outer box is meant for another seal which is where the flange part of the bulkhead will go.
Now to address the concern of mrx66699, what I am thinking is that yes, water will travel a bit through the threads of the bulkhead but will never seep out of the seal of the gaskets. So in theory, the water will seep but will be stagnant since there is no where for it to go.
Again these are just my thoughts right or wrong, but thats why we post here to learn from others.
Here is a visual of what is in my head. THe grey cirlces are the gaskets.

 

[BeanAnimal]

If the flange side is inside the outside box and is gasketed then water will not leak outside of the outside box back in between the DT and outside box but will still leak from the other side in between the DT and the box coming from the tank.

Yes and if there is a gasket between the OUTSIDE box and the TANK then the water has no place to go. It can migrate from the internal box to the DT, but that is it.

Adding a gasket between the INTERNAL box and the DT wall will stop that as well.

Even when you put an additional gasket on the outside of the DT between the DT and the outside box water will leak following the threads from inside the overflow box in the DT. It will not leak into the outside box but will leak between the outside box and the DT onto the floor.

No the gasket between the OUTSIDE BOX and the TANK WALL will stop that from happening

Bulkheads are not intended for applications of more than one wall. You will eventually have leakage between the walls from the threaded side when liquid and pressure are on both sides. They will work to an extent but its going to leak following around the threads. It wont matter where you place the gaskets as the threads go through the gaskets.

We don't mind of water migrates through the threads, we just need to keep it there with gaskets.

Two panels with a gasket in between create a seal

That said, the concern I have is being able to apply enough torque on the bulkhead nut to compress (3) gaskets without breaking the nut.

Uniseals are not a bad idea, but they are not ideal either.

If it were me, i would start from scratch and do it right. Build the external box from the same material as the tank (in this case glass) and attach it using the proper adhesive (high quality silicone).

 

[mrx66699]

I agree going to depend on the torque of the nut to seal the gasket in the center and you then chance cracking the acrylic box as its now not level and will have pressure points on it, your trying to rig it with three gaskets it can hold but not designed to as the gaskets will twist and ripple when torqued by the nut and flange any pressure and your chancing leakage

9lbs for every gallon of water and your holes I think are around 3 inches below the water level and with your tank size thats around 30 gal of watter thats around 270 lbs you might get buy but i would go with the uniseals as they are designed for this

 

[teesquare]

The quote of the day award goes to: BEAN!!!

"If it were me, i would start from scratch and do it right. Build the external box from the same material as the tank (in this case glass) and attach it using the proper adhesive (high quality silicone). "

Some things just aren't worth the compromise. Save a little money or time int eh wrong places...and UH-OH........Not good!

 

[TheFishMan65]

I think from all we have said here you can get away with one gasket between over flow and tank. Yes there can/will be a leak through threads into/from the coast to coast, display tank, and overflow. I think it was Bean who said it could be a problem in the case of a power failure - a little extra and slow leakage into your sump. I guess it could be worse - if you shut of power to and took your pump out to clean it (drip drip drip on the floor). No extra pressure to seal multiple gaskets.

The only thing I might add is to shim the overflow so it can't tip against the tank. If a side (say the bottom) could get pressed in top of the gasket might have less pressure and start to leak.

 

[bmanzie]

thank you guys these are all great thoughts. I think i am going to try it this way. As far as the water dripping when power goes out or turned off, well that will not be an issue because of the flange and gasket on the inner side of the outside box.
TheFishMan65, I will do as you say and add additional acrylic to the lower side of the outside box so there is no play as you said.
I am also planning on putting support on the bottom of the outter box to take care of the weight issue.
I am going to do a little more thinking and like I said I will send an update.
Thank you again everyone.

 

[BeanAnimal]

9lbs for every gallon of water and your holes I think are around 3 inches below the water level and with your tank size thats around 30 gal of watter thats around 270 lbs you might get buy but i would go with the uniseals as they are designed for this

The pressure on the gaskets is a function of the head against them, not the volume

That is about .43 P.S.I per foot of depth If the gaskets are 3" below the surface, then they pressure is about .125 P.S.I If you multiply that by the exposed area of the gasket, you come up with a very small amount of force trying to push water past the gasket.

In the same token, if you take the ENTIRE surface area of all (3) gaskets and divide it by the force that the nut can produce... you also end up with a fairly small number.

The gaskets will seal, but the problem becomes supporting the boxes so that they can not move and break the seal. This can be accompolished in many ways, but my feeling is that it would be easier to just start from scratch and build it "right" to begin with instead of futzing around with a bunch of gaskets.

 

[mcoomer]

Question about the PVC coming out of the sanitary tee going up to the cap. I bought a 180 gallon tank that was drilled with 4 vertical holes in one corner of the tank. In the top hole I have an 1 1/2" bulkhead and 1" bulkheads in the bottom three holes. The tank is 24" high and there is not enough space between the holes to have the sanitary tee and plumbing running straight up and down. My plan was to tip the tee's at a 45, run a short piece of PVC up to a 45 elbow and then run another piece of PVC straight up to get the caps above the water level in the overflow box. Unfortunately, if I do that I will have two pipes extending past the end of the tank and it will look like crap. I won't like it and the wife will hate it.

So, do the caps have to be at or above the water level in the overflow box? Is there any reason I can't simply cap the PVC right at the top of the tee? That would keep all the plumbing behind the tank. The tube running out of the JG fitting would have to be longer but if necessary I have room to run that pipe up to the water level and keep it behind the tank.

Let me know what you think about my idea. I can drill the tank if needed but I'd really rather avoid it if I can.

Thanks,
Mike

 

[TheFishMan65]

IIRC the caps where only for cleaning. If so they could be left off.

 

[teesquare]

The caps - or some method of air tight seal must be in place in order for the siphon to function. Make sense?

T

 

[mcoomer]

Right. I know that I need the caps. I just need to know if they need to be above the waterline or if they can be located below the waterline. I suppose that's a simpler way to pose the question. Is it OK to locate the caps below the waterline?

Mike

 

[TheFishMan65]

Yeah,what I should have said was the leg going to them could be left of so the T could be replaced with a 90 degree elbow. The leg can be left off, but the plumbing must be air tight. Thanks for reading my mind T

 

[teesquare]

No problem! Been in that spot, and found out that the "long turn" 90's work well!

 

[mcoomer]

So, I should be good. I think I'm going to fab that up, get a shot of it and post here again. All I've got to do is finish staining my stand and I can start building. Woo hoo!

 

[JoshuaG]

Quick question guys. I have 3 1" bulkheads, running an Eheim 1262 return pump, flowing about 800gph. Am I ok to go 1" all the way down or should I go 1.5" from the bulkheads down?