Electronically controlled flow control valve for air?

[okaythanksbud]

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]

So you wish to recreate the photo Below.
Use only as reference please.



Terminology you need to know.
In its simplest form.

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).

Precision Medical Air-Oxygen Blender low-flow or high-flow

Precision Medical Air-Oxygen Blender come in low-flow and high-flow offer flexibility, safety, and value. Can be configured.

precisionmedical.com

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

GB2599239A - Air-oxygen blender with periodic pressure venting - Google Patents

An air-oxygen blender 10 comprises a housing having first and second gas inlets 24, 26, a proportional mixing valve 72 communicating with the first and second gas inlets and a gas outlet 80, 82, 84 as well, the blender further having a purge valve 100 communicating with the proportional valve...

patents.google.com

US20140254305A1 - Auto-controlled air-oxygen blender - Google Patents

A gas mixing apparatus comprising an oxygen input-source, the oxygen input-source further comprising an oxygen sensor, a gas input-source, the gas input further comprises a first gas flow sensor and a combined gas output-source. The gas output source further comprises a second gas flow sensor...

patents.google.com

 

[okaythanksbud]

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).

Precision Medical Air-Oxygen Blender low-flow or high-flow

Precision Medical Air-Oxygen Blender come in low-flow and high-flow offer flexibility, safety, and value. Can be configured.

precisionmedical.com

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

GB2599239A - Air-oxygen blender with periodic pressure venting - Google Patents

An air-oxygen blender 10 comprises a housing having first and second gas inlets 24, 26, a proportional mixing valve 72 communicating with the first and second gas inlets and a gas outlet 80, 82, 84 as well, the blender further having a purge valve 100 communicating with the proportional valve...

patents.google.com

US20140254305A1 - Auto-controlled air-oxygen blender - Google Patents

A gas mixing apparatus comprising an oxygen input-source, the oxygen input-source further comprising an oxygen sensor, a gas input-source, the gas input further comprises a first gas flow sensor and a combined gas output-source. The gas output source further comprises a second gas flow sensor...

patents.google.com

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]

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.

 

[Delta Prime]

Here are some resources to point you in the right direction.

Venturi Meter Demonstrator

<B>The Venturi Meter Demonstrator provides a simple way to demonstrate Bernoulli’s Law to students.</B>VWR offers a complete catalog of instruments and tools useful for demonstrating key, basic concepts of physics that are applicable to everyday life both in and out of the laboratory...

www.wardsci.com

Amazon.com : flow through venturi

Venturi tube flowmeter | Fuji Electric

Improve the accuracy of your liquid, gas and steam measurements, even under difficult conditions, with Fuji Electric's venturi tube flow meters.

www.fujielectric.fr

 

[okaythanksbud]

Here are some resources to point you in the right direction.

Venturi Meter Demonstrator

<B>The Venturi Meter Demonstrator provides a simple way to demonstrate Bernoulli’s Law to students.</B>VWR offers a complete catalog of instruments and tools useful for demonstrating key, basic concepts of physics that are applicable to everyday life both in and out of the laboratory...

www.wardsci.com

Amazon.com : flow through venturi

Venturi tube flowmeter | Fuji Electric

Improve the accuracy of your liquid, gas and steam measurements, even under difficult conditions, with Fuji Electric's venturi tube flow meters.

www.fujielectric.fr

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]

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!