Vacuum Pump for Filament Storage

Recently, I upgraded all my filament storage bags to use vacuum storage. I bought an electric pump to go with them. While it did work, it pumped air out of the bags very slowly and was not very ergonomic. Despite the multitude of pumps available on the market, I must have picked the wrong one from the get-go. Moreover, I broke it on the first day while repacking all my spools. However, I remembered that I had some excellent and quite efficient Parker pumps left over from a PNP SMD installer project. Considering their high performance, these pumps turned out to be perfect for filament storage.   For those who might not know: most filaments are hygroscopic, meaning they absorb moisture from the air. This can lead to issues during printing, such as boiling plastic, which might make you think there’s something wrong with your printer. But that's a side note. Let's get back to the pump.   Key Aspects of the Pump Design   Main Features This pump is based on a brushless motor with two independent membrane heads. These heads can operate individually, in parallel, or in series. Parallel connection increases air flow, while series connection boosts vacuum power. If you switch the inputs and outputs, you can simply use it as a pump. Performance The pump’s performance is quite decent for our needs, quickly evacuating air from the storage bags. For the skeptics: yes, you could use a vacuum cleaner instead, but let’s not go there.   Modifications Barbs and Fittings: The pump originally came with standard barbs, which I removed. I drilled holes, tapped them to M5 thread, and installed quick-disconnect pneumatic fittings. Mufflers: I added mufflers to the pump outlets, considerably reducing noise. Power Consumption: The pump operates on just 250 mAh at 12V. I decided to use a battery with a boost converter module, and the charge lasts quite long. Control: The pump is turned on with a TTP223 touch sensor module, which has multiple operating modes depending on the jumpers used. You'l