Popup valve for Covid-19 ventialtor

Dear forum members,

I built a ventilator prototype for the Covid-19 pandemic and I'm working now on improving the pressure relief valve. I first built one with some plumbing parts but now I want to improve it with 3d prints.

This is my initial design:
Attachment 14857

Attachment 14858

Currently the rubber washer gets pressed on a metal washer to create a seal but in order to improve the seal I'm printing the following part:

Attachment 14859

Do you have better ideas how to make a better seal so I can use a weaker spring?

Maybe cast a washer form silicon? A softer washer can create a better seal with less pressure?!

By the way here is the ventilator prototype:
http://magicventilator.com/

https://www.youtube.com/watch?v=vonajMzTgMQ

It's currently fully functional :cool:

You may not like my advice here, because I'm sure you've sunk some serious hours into your design, but just buy an off the shelf pressure relief valve and adapt it to your tubing.

Real engineers (not saying you aren't one) have spent time getting paid a lot of money and running hundreds of hours of tests to develop good spring-loaded pressure relief valves that work dependably and cost not very much money. Try not to get bogged down with reinventing the tangential details of your project, you'll just sink days into something that only barely applies to what you originally set out to do.

Quote:

---

Originally Posted by Butt_blaster

You may not like my advice here, because I'm sure you've sunk some serious hours into your design, but just buy an off the shelf pressure relief valve and adapt it to your tubing.

Real engineers (not saying you aren't one) have spent time getting paid a lot of money and running hundreds of hours of tests to develop good spring-loaded pressure relief valves that work dependably and cost not very much money. Try not to get bogged down with reinventing the tangential details of your project, you'll just sink days into something that only barely applies to what you originally set out to do.

---

I tried looking for one but I had trouble finding the right one. Most pressure relief valves on market are in the range of 10-300 PSI while I need one rated 0.85PSI (60 cmH2O). I guess the only manufacturers for such valves will be medical manufacturer that will charge a lot for each valve.
Please let me know if you can find a website selling 60 cmH2O pressure relief valve.