Oscillating Airflow Pump? 1

[Helepolis]

Hi all,

I'm working on a prototype of a medical equipment that needs to be ventilated (simulating breathing or patient ventilation) and I'm searching for possible solutions.
This will be the second prototype, when the first one had a servo driven pinion that drove a rack that was connected to two 150mL syringes, while the servo was controlled by an Arduino Uno controller.
This Arduino was connected in parallel to another Arduino Uno and both of them control all of the systems in the prototype.
The Arduino of the ventilating mechanism was controlling and synchronizing the ventilation parameters (i.e. air volume, ventilation frequency) depending on the actions of the other systems, so basically the ventilation mechanism has to have at least the possibility of receiving signals.

Now the requirement is to upgrade the machine and give it a bit more off a commercial look, and so far those are my options:
1) Incorporating a commercial Med. ventilator – the problem is that all of the ventilators that I’ve checked doesn’t have the ability to receive a signal and change its operation according to the signal.
2) Using a linear actuator and a pneumatic cylinder – this is the preferred option so far as I can interface the actuator with an external controller.
3) Using an air pump – I can reverse the current (using a relay for example) and by that reversing the air flow direction but since I’ve never worked with air pumps, it feel to me that the reversal will produce a jittery air flow and inaccurate and inconsistent air volumes.
I can figure the second option out by myself, but I’m wondering if It’s possible to make it more self-contained like the pump option.

So after I’ve explained what I’m trying to do, I need help with figuring the pump part.
Is there a reliable small air pump with DC motor (for controlling the speed and direction) that can deliver accurate volumes of air and can be stopped and reversed “on a dime” so to speak.

P.S.
Any other ideas and suggestion are more than welcome!

 

[EdStainless]

It sounds like a diaphragm pump driven by a control motor would work.
What kind of pump is in the commercial units? I have seen some that have continuous supply and suction, and then they open and close valves to control the flow. But that sounds like overkill.

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P.E. Metallurgy, Plymouth Tube

 

[Helepolis]

What kind of pump is in the commercial units?

From what I've seen the commercial units use a turbine or an air cylinder.

 

[TenPenny]

Your description sounds halfway to a CPAP machine. Most of them are configurable. Or maybe BIPAP.

 

[Helepolis]

Well I have never seen a CPAP or BIPAP machine that has any sort of I/O ports.
If I'm not mistaken they are self containing stand-alone machines.

 

[Artisi]

Are you trying to re-invent the wheel?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Helepolis]

Are you trying to re-invent the wheel?

I know it looks like that, but no, and i dont get your remark.
What is so wrong in trying to find a diffarent way for doing something. Maybe based on someones respones i'll be able to do something clever or out of the box.
Since when asking a question, even if the answer might be obvious, became a taboo?

 

[Artisi]

A legitimate question, have you carefully analysed ever similar unit currently out there for good / poor ideas, how to improve on what's available, improve on the good points and look at ways to correct any poor design.
I was told years ago to look at the best available and improve on it.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[TenPenny]

"Well I have never seen a CPAP or BIPAP machine that has any sort of I/O ports.
If I'm not mistaken they are self containing stand-alone machines. "

Hence the 'halfway to a CPAP machine' comment.

And a BIPAP machine works in both directions, and they are generally configurable.

Sounds like that would be a logical starting point, but if you want to start from scratch, go ahead.

 

[Helepolis]

A legitimate question, have you carefully analysed ever similar unit currently out there for good / poor ideas, how to improve on what's available, improve on the good points and look at ways to correct any poor design.

It’s an excellent advice, which I try to always follow but the time frame I have to upgrade the prototype to a more "commercial" look is very limited, so I don't have the privilege of doing this kind of research. Of course in the future, if the system is approved, I'll be able to make a more in depth research.
And besides, the ventilation mechanism is a small part of a larger array of mechanisms in the system that will work together, so I allocated a small amount of time to see if there is another way for the system to be ventilated.

And a BIPAP machine works in both directions, and they are generally configurable.

This is the point, I don't care if the machine can be configured, I need it to be able to receive signals from an outside source and act according to them.
So far I didn't find any such machine that can receive signals, the closest feature I found in those machines is sending signals to monitoring equipment.