Anyone have a suggestion for main drain bubbler?

[Ralph III]

Hello All,
I was wondering if anyone had a suggestion of introducing air bubbles into the main drain? I think the girls would get a kick out of such a feature. Not your typical bubbler which creates a fountain affect on the surface. I just want a lot of bubbles to come out of the main drain and rise to the surface.

I have a typical circulation setup whereas a three way valve is used to control the inlet water between the skimmer and main drain. I however could easily redo the plumbing and add another valve to make the main drain both and inlet and outlet. However, what would I use to blow air through the plumbing to create these bubbles?

Thanks,
Ralph

 

[Jimrahbe]

Ralph,

I'll be the first to admit that I don't know much about fluid dynamics, so I could be all wet...

It seems to be that if you introduce air at the equipment pad, it will stay on top of the column of water going to the main drain. So, for air to come out of the main drain, you would have to displace all the water in the main drain pipe. I would assume that would take an air compressor of some type.

Interesting idea.. let's see what our other members have to say.

Thanks for posting,

Jim R.

 

[PoolguyinCT]

We do this every fall in New England, that’s how we purge floor drains. A blower is used.

Ask your self how bad do you want to do this, it will require electrical service, blower unit & full top side manifold chop out & replumb.

And this is contingent on having a dedicate MD line to start with.

A cheap thrill is not going to be cheap.

 

[Ralph III]

We do this every fall in New England, that’s how we purge floor drains. A blower is used.

Ask your self how bad do you want to do this, it will require electrical service, blower unit & full top side manifold chop out & replumb.

And this is contingent on having a dedicate MD line to start with.

A cheap thrill is not going to be cheap.

Well, that is why I made the inquiry but you didn't offer any specifics? Re-doing the plumbing and adding some electrical service is no big deal for me though and wouldn't be very expensive. I am not sure what you mean by top side manifold and what type blower?

Quote by JimRahbe...."It seems to be that if you introduce air at the equipment pad, it will stay on top of the column of water going to the main drain. So, for air to come out of the main drain, you would have to displace all the water in the main drain pipe".​

Yes, you are essentially correct. As long as the system were sealed though any compressor capable of introducing air into the plumbing will eventually introduce enough air that it would come out of the main drain.

The question is what type of pump/compressor would you use and how much pressure will be created because pvc is limited with psi.

Thanks,
Ralph

 

[JamesW]

8 feet of water column is only about 3.5 psi. The plumbing is not the issue.

Most blowers can't supply air at that depth. Maybe a 3 hp commercial blower. It would need to do at least 100 inches water column static plus whatever dynamic is introduced based on pipe size and air flow rate.

Continuous operation at that pressure creates a lot of heat and the temperature might exceed the PVC rating.

A pool winterizing blower can blow out a main drain but I don't think that it's rated for that pressure for continuous blowing.

A compressor can do it but a compressor is really not designed for the application.

You will also have to derate any diving ratings if you're introducing a lot of air because the water density is reduced.

Basically the plumbing would be valves (2 or 3-way) to isolate the main drain and connect the blower.

The blower would need to be mounted per the installation manual and powered as in the manual.

 

[PoolguyinCT]

Well said james. Blower & cfm. Compressor won’t do the deed.

3 way installed on drain riser horizontally, stub high & mount blower and relevant accessories.
Power source & bond.

Since he is not looking to return water to floor, 1 three way valve should do it.

 

[Ralph III]

Thanks for the input.

Ok, so I've got another idea in regards to the subject?

Instead of attempting to blow all of the water out of the main drain line with air only, in creating a bubble effect, what if I simply used a valve to make the main drain a return? Could I then introduce a compressor into the main drain line that would add air bubbles?

In that case, would the return water push the air bubbles down and out the main drain? I'm assuming it would because you always get bubbles when there is an air leak in the return system but that is of course with horizontal return jets. The effect wouldn't be as great but it could still be interesting/fun.

Ralph

 

[PoolguyinCT]

A compressor won’t give you the dramatic effect.


Just a couple bubbles, go for the gusto!

 

[Winnie-the-Pool]

Just a thought... I don't know how many bubbles it would produce, but maybe you could fish aquarium tubing down through the main drain pipe, pull it out through the main drain cover and attach an aerator stone. Then use a fitting in the main drain pipe similar to what is used for a Stenner pump to connect an aquarium air pump. You would probably need to weigh the aerator stone down and install a check valve to prevent the tubing from filling with water. It would obviously work better when the pump is off or the main drain valve is closed so it doesn't suck the bubbles in.

You could test it prior to attempting to fish the tubing by just weighing the aerator stone on the bottom to see if you are going to get your desired bubble effect. Or you could just use it like that as a temporary feature and not mess with your plumbing.

Does that make sense?

 

[Ralph III]

Just a thought... I don't know how many bubbles it would produce, but maybe you could fish aquarium tubing down through the main drain pipe, pull it out through the main drain cover and attach an aerator stone. Then use a fitting in the main drain pipe similar to what is used for a Stenner pump to connect an aquarium air pump. You would probably need to weigh the aerator stone down and install a check valve to prevent the tubing from filling with water. It would obviously work better when the pump is off or the main drain valve is closed so it doesn't suck the bubbles in.

You could test it prior to attempting to fish the tubing by just weighing the aerator stone on the bottom to see if you are going to get your desired bubble effect. Or you could just use it like that as a temporary feature and not mess with your plumbing.

Does that make sense?

No that makes perfect sense and actually crossed my mind. I worried about the tubing getting sucked into the pump somehow though so didn't ponder it. An aerator stone is a good idea though.

Ralph