Quarter turn connection for plastic tubes — Design idea request

I'm developing a 3d project using AutoCAD 2013 and I would like to request ideas for a specific problem. It is not for a commercial project.

It is about how to connect two hollow plastic pipes using a "quarter turn" design.

The only thing that'll run inside them is non-pressurized water.

Is there a way to implement a locking mechanism inside the thickness of the pipes?

All measurements are available next to the picture, in millimeters.

The goal would be to:

— Connect them without using any tools
— Be easy to connect and disconnect
— Have no water leakage outside of the pipes
— Have a clean design (nothing hanging from the inside or from the outside)
— Have the locking mechanism implemented inside the thickness of the pipes, at their extremities, 10mm max width, no plastic doohickey on the outside to lock or unlock

I keep trying to find a way to implement the following design but i'm just not visualizing in my mind how the mechanism would work.

http://www.emka.com/in_en/quarter-turns/standard/plastic-quarter-turn/

— Picture:

Any ideas would be appreciated.

Thanks in advance,

Thiago.