Adjustable Room Air Filter System for Different Sizes of Cylindrical Air Filters

As a part of my mechanical engineering study degree, I have designed an adjustable and cost-effective air purifier system tailored for student rooms, that combines learning, sleeping and hang-out areas. Since most air filter systems only support one type of filter size, I came up with a design that allows it to be used by different-sized cylindrical filters to ensure easier accessibility.

By focusing on affordability and ease of construction, the air filter system design can be easily rebuilt. All CAD files for the air filter system are available for download and can be adjusted and modified to fit specific dimensions.

This air filter system is a practical and working solution for improving indoor air quality.

List of Tools:

Screwdriver, wrench or plies, laser cutter, power supply (12V, ≤2.5A).

Instead of a laser cutter it is possible to use saw and drill with wood drill bits (6mm, 8mm, 10mm, 14mm)!

Material:

2x Wood plank 250x250mm (3mm thickness)

2x Wood plank 250x250mm (6mm thickness)

1x Laptop fan 150x150mm

1m threaded rod (M10)

1x HEPA Filter cylindrical (max. height: 290mm and max. outside diameter 200mm)

12x washer (M10)

4x cap nut (M10)

8x hex nut (M10)

1x PWM-Controller

1x little box to hide the cables and the other parts

0,56m carbon pipe (or other material) (14mm outer diameter)

0,56m carbon pipe (or other material) (8mm outer diameter)

4x small female to female wire

Glue

Cut the wood panels according to the drawings/.step files.

Cut the 1m threaded rod into four equally long pieces (250mm each).

Glue the 6mm wood panel with the square in the middle on top of the 3mm wood panel with the 117mm hole in the middle.

Glue the 6mm wood panel without the square to the 3mm wood panel with the 200.5mm hole in the middle.

The threaded rods with the hex nut can help to keep everything in position and tight together as longs the glue is drying.

In my particular case I was using clamps provided by my university workshop.

After the glue dried and everything is in place the 4 threaded rods can be pushed through the holes and the cap nut as well as the hex nut can be mounted.

Install the fan using the little 6mm holes on the wood base and make sure the fan is aligned with the 117mm hole.

The fan should be installed from the bottom to ensure a flat surface for the filter.

The use of a pulse-width-modulator controller helps to adjust the speed of the fan and allows the fan to be turned on and off at the device itself, without cutting the power to the device.

It is important that the power+ is connected to the 12V power supply+, and the power- to the minus, respectively. (See picture)

The motor+ connects to the 12V input of the fan and the motor- connects the GND of the fan. This works as well with a two wired fan but I had a 4-pin fan laying around. Picture for reference.

It is useful to install the electronics inside a small boy to prevent unwanted mechanical damage to the smaller parts.

Before assembling everything together, each carbon pipe should be cut into 4 equal pieces of 140mm. The carbon pipes can be glued in the four holes that are only in the 3mm thick wood panel.

The carbon pipes are positioned there to prevent accidental contact with the filter.

Once everything is glued and installed in place it is time to add the HEPA filter and put the wood top part, including the fan and the electronic box on top. Install 4 more washer and hex nuts and tighten the nuts until there is no space between the filter top and the wood top (be careful not to squeeze the filter too much).