This is my first Instructables post so please forgive me for my mistakes.
First of all, I've thinking about to build in a valve in to the pipe of our cooking hood, because when it's turned off, it's starting to flow the cold air in to the kitchen and it's really annoying. I've tried to buy a valve but I have only found some wall-mounted type with inadequate diameter so I decided to build one. I needed about 1-2 hours and the materials costs was about 4$
1x plastic cover - I decided to use plastic instead of cardboard because the possibility of getting wet
1x cloth or something easy thermo isolant material - To keep out the cold
1x body of a pen - or any cylindrical thing to make the movement easyer
1x bowden cable - or any harder material as an axe for the valves
1x round base - I used a connector pipe with a smaller diameter than the pipe
1x hot glue gun
Step 1: Cut the Pen Housing Into Equal Pieces and Cut the Plastic and the Thermo Isolant to the Correct Size
I have used a permanent marker to draw the correct form then I cut it with the scissor.
I've used some emery paper to make the edges of the pen housing smooth so it won't lags later
I cut a ring from the termoisolat material to make the contact surface more tight
Step 2: Cut the Plastic Cover Into Two Pieces and Glue It Together With the Pen Housing and the Thermoisolant
I've bent in the middle the plastic to see the centerline after that I've cut it
I put the bowden cable in the center of the pen housing and arranged them to a small distance and in the middle between the two plastic cover, when it was good, I put some drop from the hot glue and checked if it's moving smooth. It's better to put only a drop because if something wrong, You can easily remove the wrong positioned piece and put it in the correct position.
When everything was fine I put a littlebit more glue to be sure that remains in the position.
After that I've glued the thermoisolant to the bottom
Step 3: Mount the Valves
I've mounted the thermoisolant ring with the hot glue.
After that I have checked if everything works fine and I realized that I have to cut out some of the edge (second picture) to have room to mount the bowden (axe).
I cut a piece from the pen cartridge and glued between the pipe and the bowden to keep a coorect distance ensuring the mobility of the valves.
I had to cut a littlebit more from the edges of the valves to ensure the mobility
After the first test I realized that I have to ensure that the valves doesn't flip over or stop on vertical position so I put a cross to the top made from the pen cartridge.
Step 4: Testing
I just put over the exhaust pipe of the exhaust hood and started the ventillator at different speeds
Step 5: Mounting Inside the Pipe
After all, when everything was fine I've mounted the valve inside the pipe with the hot glue gun, but maybie it would be easier simple silicone because there wasn't enough room for a nice work, but I'm a littlebit impatient so I made it with the hot glue.
I was mounted it in a position in which will be over the line of the ceiling so the cold air will stay outside of the kitchen