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Electronically controlled flow control valve for air?

okaythanksbud

Sep 26, 2023
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I'm working on a capstone project in which I'll need to create an oxygen blender. This pretty much entails being able to control the flow of oxygen and room air from one input, which will likely be a single dial the user can turn to adjust the concentration of oxygen in the mixture. The first thing that came to mind to achieve this was a way to adjust the flow rate of ambient air and oxygen simultaneously (determined by the dial) to obtain the desired concentrations--the easiest way to do this (I would think) would be by using a microcontroller to automatically adjust the flow rates of both gasses (depending on the dial). However I don't really know if such a valve exists--I know solenoid valves are electronically activated but I dont think there's any way to control flow rate (looks like these either block flow or permit a certain flow past) so I can't see these being very useful.

So essentially what im looking for is something in which I can apply a voltage that will control the flow rate of gas through the element. I've tried looking this up but the language used to describe all the components that come up is super vague and doesn't really give me a clear description of what im looking at--but I also have almost no knowledge of pneumatic components so it could just be my fault. The most promising link I've found is this and this but I have 0 idea if these do what I want.

I hate to ask dumb questions like this but I figure its better to ask people who know what they're doing rather than 4x longer trying to figure this out on my own. Thanks for any help
 

Delta Prime

Jul 29, 2020
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So you wish to recreate the photo Below.
Use only as reference please.

Screenshot_20231127_015911.jpg

Terminology you need to know.
In its simplest form.
Screenshot_20231127_020522.jpg
This basic information was and is available through the link I have provided you with, in your other thread. The "National institute of health" (NIH).


Below are a couple of resources specific to your query. They are patents complete with explanation and the components themselves via pictorial diagram.


 
Last edited:

okaythanksbud

Sep 26, 2023
8
Joined
Sep 26, 2023
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So you wish to recreate the photo Below.
Use only as reference please.

View attachment 61818

Terminology you need to know.
In its simplest form.
View attachment 61819
This basic information was and is available through the link I have provided you with, in your other thread. The "National institute of health" (NIH).


Below are a couple of resources specific to your query. They are patents complete with explanation and the components themselves via pictorial diagram.



Like I've said I have little experience, but one thing I've seen is that complexity/cost doesn't correlate with efficiency. For example Ive seen studies showing that some bcpap devices worth thousands of dollars have performance comparable or worse than devices that cost a tenth of it. There's also a device, the Pumani bCPAP, which just includes a control valve for oxygen flow--the user can't manually set the oxygen concentration. They literally have a table telling the user what flow rate of oxygen to use for a certain concentration of oxygen (p51). I'm not looking to make something as precise as a medical grade oxygen blender, just something that allows the user to change the proportion of oxygen without needing to rely on something like a table.

Regardless, even if just for my own interest, does such a device exist?
 

Delta Prime

Jul 29, 2020
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I'm not looking to make something as precise as a medical grade oxygen blender, just something that allows the user to change the proportion of oxygen without needing to rely on something like a table
All that dial is doing in that medical grade oxygen blender is pinching a tube that's it. In conjunction with flow meters.
You're about to get into physics it's called the Venturi effect.
Fluid dynamics, differential air pressure. As it demonstration you can make your own.
Notice in the diagram A2.
That is a choke or a bottleneck this is what that medical device is doing constricting the air pressure differential. I hope this paints a picture for you.

1701107157794.jpg1701107182249.jpg
 

Delta Prime

Jul 29, 2020
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Here are some resources to point you in the right direction.



 

okaythanksbud

Sep 26, 2023
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Here are some resources to point you in the right direction.



Thanks so much--super interesting. Definitely works much different than I thought, its incredible that this can be made precise enough for medical grade oxygen blenders. Appreciate the links a lot.
 

Delta Prime

Jul 29, 2020
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Joined
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Messages
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Thanks so much--super interesting. Definitely works much different than I thought, its incredible that this can be made precise enough for medical grade oxygen blenders. Appreciate the links a lot.
A belated;Welcome to Maker Pro!
:)
 
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