Splice in T-pipe into existing spiral pipe

[bjolo360]

Hello
I'm having a bit of trouble with how to handle the ventilation on the upper floor. I have an existing spiral duct that I would like to "squeeze" a T-junction into afterward, so to speak (I hope you understand what I mean).
How should I fit the new into the T-pipe? Since the couplings (or whatever they are called) are a bit longer, it's not possible to just cut off the existing one?

 

[Allmänobildad]

http://www.luftbutiken.se/nippel-muff/533-langnippel-stl-125-langd-200mm.html

 

[Manberg]

http://www.luftbutiken.se/t-ror/5313-avstick-160-100.html or suitable dimension.

 

[bjolo360]

[link] or suitable dimension.

That seems perfect, thanks!

 

[mexitegel]

What a smart gadget, I'm going to use this when installing an additional exhaust vent in the kitchen