SV08 Modular Chamber Heating, Filtration/Extraction/Recirculation system - Klipper controlled

Fan System

This fan system is dimensioned to replace the glass rear top panel of the official enclosure, but it can be used with any compatible enclosure.

Operation

With the doors fitted the valves are open and chamber air is filtered and recirculated back into the chamber. This is the configuration for materials like ABS.

Remove the doors and the valves drop down to block off noise and ensure only filtered air is expelled into the room.

By removing the lids, you can easily replace the filters.

The fan unit has a thermistor placed through the 5mm hole of the right-hand fan unit

Components

The fans I used are 120mm Arctic P12 MAX: ARCTIC P12 Max - PC Fan, High-Performance 120mm Case Fan, PWM controlled 200-3300 rpm, Optimised for static pressure, 0dB mode, Fluid Dynamic Bearing - Black : Amazon.co.uk: Computers & Accessories they push a lot of air and are quiet. I used a 12V buck converter for power.

The HEPA/Carbon filters are H128 compatible 3 Pack Replacement Filter Compatible with LEVOIT LV-H128/PUURVSAS/HM669A/ROVACS/RV60 Air Purifier, H13 True HEPA Filter, 3-in-1 Activated Carbon Filters, Replace #LV-H128-RF : Amazon.co.uk: Home & Kitchen they clip into the filter-frame

The additional carbon filtering is provided by 2 layers of :PUREBURG Carbon Filter,Cut-to-Fit Carbon Pad 16 x 48 inches for Charcoal Sheet fits Range Hoods Furnace Filters, Food cycler filter. Kitchen Compost Bins Filter removes Odor VOC Replacement,1-Pack : Amazon.co.uk: Home & Kitchen cut to fit a second filter-frame.

You then stack them, fitting the carbon filter and then place the HEPA filter on top. There is enough space to add additional filtering if you need it.

Printing

I recommend you don't use PLA for the fan boxes (I used PETG).  My SV08's enclosure when fully insulated can exceed 65 degrees with active heating - PLA parts will droop.

I used ABS for the Valve but PETG should be OK. I recommend the same for the Klipper Expander Mount

The doors and top lids should be PLA for stiffness.

3 x doorknobs: https://www.printables.com/model/447521-small-knob-opt-with-m3-insert

Active Chamber Heater

The duct must be printed in ABS or ASA (PETG will get too soft). The temperature can exceed 90 degrees in the small space. 

Klipper control

The fans temperature monitoring and the heating system are all done with a Klipper Expander. You can find my guide to adding a Klipper Expander board with Katapult to your SVO8 here: https://drive.google.com/.../13SQ8KijvDe3On54f8cEuNPnZJ0D...

I've created this folder which contains a guide to installing Katapult onto the Klipper expander board. It was a new process for me but as I could not find a guide on the web I decided to write my own.

If you trust my binaries you can skip a few steps. I've also provided a batch file based on the Sv08 Mainline one to automate adding Klipper on to the board which is useful when klipper needs an update.

The Expander MOSFETS can drive 3A maximum - this is too low for a heater unit. My heater is a 150W PTC, when cold it can draw 10A. My solution was to use the Expander MOSFETs to drive more powerful MOSFETS rated at over 20A. DollaTek 5Pcs D4184 MOS MODULE MOSFET control Module Field effect MODULE: Amazon.co.uk: Business, Industry & Science

If people are interested let me know and I will post the complete circuit.

I also split the PTC heater into two elements to give me more control,