How to get two 'pipes' through one round hole?

[Chris Green]

Is there any 'off the shelf' way of getting two water connections through a single round hole?

I want to get a water feed (for something that needs *very* low pressure water) out through the overflow hole of a toilet cistern. It currently has a straightforward 22mm plastic pipe through the hole with rubber seals.

The overflow hole is in the bottom of the cistern, it's the length of pipe sticking up through the hole that defines the overflow level. So I want to duplicate the existing pipe but have (say) a small pipe that enters the side of the 21.5mm below the cistern, runs up inside the

21.5mm, and then comes out below the normal surface level inside the cistern.

Any ideas?

I guess I could simply get some small diameter PVC flexible pipe and glue what I've described above, it's very low pressure.

[Max Demian]

Do they make coaxial pipes?

[Iggy]

replying to Chris Green, Iggy wrote: Maybe you should label or describe your goal or invention. Are you aiming to make a Bidet, Dog Water Bowl Filler or what. Otherwise, I don't think the plan/idea/invention is a good one...emptying the cistern uncontrollably is flawed. The overflow tube doesn't go anywhere that you can fish even a small tube to anywhere else.

Your best bet is to either buy a Bidet kit that connects to or replaces the toilet's supply valve at the wall or floor. OR, to Tee off of the Bowl Fill Tube that dumps into the top of the overflow tube...this would then be run out of the toilet's breather hole at the top edge of the cistern and run to wherever. However, this is only active for the cistern refilling period.

[Chris Green]

Possibly, but the 'take off' underneath would be a bit complex and expensive. I need a simple, cheap solution.

I've taken the existing overflow pipe out, it's bigger than 21.5mm inside the cistern and it's not PVC (won't solvent weld) so my idea above probably won't work very well.

[Roger Hayter]

Non-reinforced PVC tubing of exactly the right size (a geometry exercise!) would probably compress into two equal 'D' shapes. Silicone would be too soft, possibly. Then one could continue and bend back and the other be cut of flush with the overflow level.

[Chris Green]

Yes, a solution like this had occurred to me.

However I think I have a better solution, if I change the flush mechanism to one with a built-in overflow then I can dedicate the old overflow outlet to my low pressure water supply. Screwfix have (at least) two siphon type flush mechanisms that have built-in overflow and they're only about £5.

[Nightjar]

Be careful about reducing the cross-sectional area of an overflow pipe. It is matched to the inlet pipe size (which should be 15mm if the outlet is 20mm) so that an overflow does not back up and come out of the top of the cistern.

[John Rumm]

Its relatively easy to make a concentric pipe set with (preferably) end feed fittings... (can be used for things like diy Surrey flanges etc.

You need a length of 22mm pipe, and some 15mm pipe at least 8" longer. Two 22mm equal tees. Four 22mm male to 15mm female fitting reducers.

Solder a fitting reducer into one end of each tee. Now insert the 15mm pipe right through the fitting reducer on the first tee (i.e. tap it past the end stop such that it comes right through the reducer, and out the other end of the tee, and carries on.

Now slide your 22mm pipe over the 15mm pipe sticking out of the tee, and settle it in the socket on the other end of the first tee.

Next do the same trick with the second tee and a fitting reducer to close off the far end of the 22mm pipe.

You should now have a length of 15mm pipe passing right through a section of 22mm, and have two spare tee connection points where you can connect either a pair of 22mm pipes or another two 15mm pipes with the extra fitting reducers.

[Chris Green]

It's actually a chicken waterer that I want to supply, they have valves which close when full but need a very low pressure supply.

[newshound]

I knew there had to be a way. A truly cunning plan!

[Iggy]

replying to Chris Green, Iggy wrote: Thank you. Yep, I'd have to side with leaving the toilet itself alone and put a Tee or 3-way valve (

) between the toilet's wall supply valve and it's hose/tube. That way, you can just crack it open a hair or regulate the pressure to exactly where you need it. Turn it off for cleanings too or now have a hose-out solution after any illness episodes in the coop. However, you may have to go to a Plumbing Supply store or Automotive Parts store, if the size you need isn't at a regular Home store.