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I have assembled my prototype with empty bottles, a plastic container, two aquarium water pumps and electronics that you can buy at Amazon or electronics stores.
The basic design of the respirator is based on the use of water columns to produce the gas exchange in the lung in a simple way using materials that can be found in any store.
The idea is to be able to go to a DIY store and have the material needed to make a respirator.
In case of emergency, as we currently have with the Coronavirus, it is necessary to be able to quickly build equipment that is sufficiently reliable, with materials that are easy to locate and assemble, without having to develop new material that needs many hours to check its durability and operation.
For people of my age, this is the respirator that McGyver would build.
Breathing basically consists of introducing a certain volume of air into the lungs at a certain pressure, which causes the exchange of oxygen in the alveoli for carbon dioxide and the subsequent expulsion of this air.
There are many electro-mechanical or simply mechanical breathing aids. In all of them it is very important to regulate both the volume introduced and the pressure at which the air is introduced.
A common problem is how to carry out the control so that no more air is introduced than necessary or at more pressure than necessary. In mechanical or electromechanical systems it is necessary to have electrical locks, torque control, safety valves that guarantee this control, etc...
If a hydraulic system is used, we have many advantages since in any hardware store we find a lot of material dedicated to the subject, more than for air control, so in case of emergency, we will have a lot of material, spare parts, etc.
Most importantly, with very little knowledge we will be able to make a small respirator.
How it worksHow it works
The operation of the respirator is based on using a column of water to move the volume of air at a controlled pressure and a controlled volume.
This is the simplest and most basic model of a ReaMima system, a small pump and three containers. If you want more details go to simple model
Taking into account that the volume of air we have to introduce in the lung (tidal volume) is 7ml/kg of body weight, we have to design the system according to that calculation. To avoid complications, it is best to indicate on the respirator that it should not be used with people weighing more than 100 kg and define our maximum air volume as 700 ml.
In the following image, you can see that the volume of 700 ml is our working volume, so the area striped in green is our safety margin. We must leave at least half or equal to the volume we are going to use as our safety margin.
In the initial tests, I used an empty plastic bottle to which I cut off the bottom cap.
With access to more materials, you can use plastic or metal.
It is important to mention that the container used must be clean, must not release gases, particles or elements harmful to health and must be able to be disinfected with alcohol, bleach or similar.
Likewise, it must not be able to deform under pressure, as it can deceive us with the volume insufflated.
The size of the compression tank must be large enough to store a minimum volume of water and a maximum volume that will allow us to work correctly.
you have all the rest of the project on the web :