Recoil flap for air handling systems

For a long time we have been dealing with the air conditioning we share with our neighbour below us, he is an avid smoker and an elderly gentleman. Some time ago he did a complete renovation of the apartment and the air ducts which are only sized to pull air from the toilet and bathroom were oversized by 3x stronger fans and a hood was added 😃 As a result, the smell of smoke from the toilet wafted into our entire apartment when he was in the middle of putting one on. Or what the neighbor was cooking, plus a huge amount of dust was coming into our apartment from the HVAC. The return dampers built into the riser are just sheets of metal, and when they drop their fans it lifts them up from the bottom and it all comes to us.

The following diaphragm check damper consists of only two parts and two layers, it slides into the gap between the fan and the duct as shown. I used standard instant glue to glue the parts together.

There are 2 versions of the model:

• V1 is the version for installation before narrowing as in the picture.
• V2 is for installation where the duct path is not reduced to smaller.

V3 is being prepared for installation behind the constriction for maximum efficiency. It will be added as a separate project.

My setting:

• Layer 0,30mm
• Nozzle 0,4
• PETG
• 250°C x 75°C
• Perimeters 500 😃
• Extrusion width 0,75mm for all (perimenetrs, infill …)
• Fan 1% (just like that)
• In case of using a layer height of 0.30mm, I recommend to set the height of the model to 0.6mm, so that two layers of printing will appear.

Pokud budeš chtít něco jinak, stačí napsat a dohodneme se :)

If you want something different, just drop me a line and we'll work it out :)