Our Journey of Creating A DIY Oxygen Concentrator (Part 1)

Table of Contents

Part 1 - Introduction

Coronavirus - ProjectOxy

Right after India coped up with the loss of lives, exhausted healthcare system & resources, it was hit by the second wave of Covid-19 in April 2021.

Not everyone was prepared for it, people became restless, the healthcare system started grinding again, but chaos surrounded medical oxygen due to its acute shortage.

Some people started turning towards oxygen concentrators to save the lives of their loved ones but these devices were expensive and way beyond reach for the majority of the population.

However, oxygen concentrators proved to be effective especially for patients who frequently required medical oxygen and for patients who couldn’t find oxygen cylinders or ICU beds with oxygen.

There was a need of indigenous oxygen concentrator that was effective, affordable and easier to build through DIY. Unfortunately, such a thing was not available. Addressing this, ProjectOxy started an initiative building upon the open-source design of OxiKit.

Engineering Team

The engineering team at ProjectOxy started off with limited resources during the lockdown imposition in the nation.

Why did our Engineers Choose An Open Source Project and Oxikit?

Our Engineers focused on finding open source solutions for addressing acute shortage of medical oxygen to avoid reinventing of solutions.

They studied & analyzed various open source projects and finalized Oxikit as it had pretty detailed guidelines. Moreover, all the information provided by it was good enough to build our own prototypes.

However, the lockdown created multiple hurdles for the team

Lockdown in India - ProjectOxy

The top three hurdles were:

  • One of the main hurdles was procuring components, tools and other resources to build the concentrator.
  • Another hurdle was procuring the exact resources required by the OxiKit design for example, procuring Zeolite from manufacturers was difficult as mostly it was out of stock.
  • The engineering team also modified some components according to the resources available in the local market for example, the filters for the sieve were replaced by readily available meshes in the market.

The third step was crucial to make the oxygen concentrator easier to build through DIY in India.

What Else?

While the engineering team was working towards building a sustainable, affordable, and easier to build oxygen concentrator with parts readily available in the local market, the growth team at ProjectOxy was working towards building a portal.

This portal was a way to create a community where different users could interact, and people looking for covid relief resources could get in touch easily with relevant users.

Why Are We Sharing These Details?

It took us approximately 2 months to get where we are today; we are about to complete this project. We are documenting our journey and sharing it with everyone out there so it can help more and more people.

What’s Next?

Stay tuned with us as we will keep posting our updates that can help you learn how to create your own DIY oxygen concentrators.

Thank you for your attention.

Keep Learning!


Note:
We use parts readily available near us, but some of these components/parts/tools may not be available near you. Please use your own knowledge, expertise and creativity to use the next best alternative components/parts/tools.

Part 2 - Procuring and Assembling of Materials

Procuring and Assembling of Materials - ProjectOxy

The engineering team started procuring parts and discovered that some oxygen concentrators have a larger output capacity which can serve more than one patient. For this to happen, a splitter with a pressure gauge & a humidifier was needed to control the output, which was commercially available.

They also found out about the local suppliers for each component; Zeolite, Compressors, Electronic Components, Sieve Design parts.

The engineers invested the initial period in studying, analyzing and R&D of using different compressors of

  • 0.7hp,
  • 1hp and
  • 1.5hp 

The engineers also studied the impact on the final output of each compressor and feasibility of sieve design by using PVC instead or metal cylinders.

Orders were placed for electronic components and Initiated the process of Custom design for the sieve using PVC.

Zeolite - Hard To Procure

Zeolite - ProjectOxy

Our Engineering team encountered difficulty in procuring oxygen filtering zeolite. Our engineers realized that it is not readily available in India so they parallely started finding alternative methods for oxygen generation (Electrolysis, cryogenic distillation, vacuum swing absorption).

Reverse Engineering Oxygen Concentrator

Our Team in Florida received a commercial oxygen generator and dismantled it to examine and study the various parts and its working. The parts were very closely relatable with oxikit design. This gave our engineers more confidence that oxikit design is good for building a DIY oxygen concentrator.

What About Alternative Solutions To Oxygen Concentrators?

In the process, our Engineering team also discovered the drawbacks of some methods:

  • Electrolysis method:- It is not commercially viable for many reasons such as heat generation, slow rate, oxidation of electrodes, hydrogen dissipation etc. Hydrogen dissipation was the main reason the electrolysis method was not used as hydrogen is very volatile in nature when it comes in contact with oxygen.
  • Using Tyre inflator compressors to build an oxygen concentrator is a bad idea for certain reasons. Firstly, it is not built for a longer duration. Secondly, it doesn’t generate enough pressure and gets heated up quickly.

Hence, our engineers came to the conclusion that the oxygen concentration method is the easiest and safest approach. Therefore our Engineering team consolidated all researched base work majorly for:

  • Alternative methods of oxygen generation,
  • commercial solutions,
  • electrolysis

They also studied the software program from Oxikit along with programmed it onto Arduino and ran the code to eliminate any software setup issues.

Making of Sieves and Alterations done

Our Engineer team made sieves with normal pvc pipes (with end caps made of M seal) but in the process and R&D testing they noticed Borwell pipes turned out to be the best for sieves for a few reasons:-
  • As M seal end caps are not completely air tight plus Normal Pvc pipes were not durable enough to handle the pressure and temperature variance.
  • Our team tried Borwell pipes which had the capacity to withstand the pressure up to 200 PSI
So once lockdown was revoked; they ordered borewell pipes for Sieves, the specifications are given below:-
  • 3 sets of pipes ( 20 inches each in height) 
  • Diameter of 2.5 inches
  • 8 End Caps of (75mm) each 
Note: You can find the following parts in the following places:
  • Borewell Pipes: Agro-industrial shops
  • End Caps: Any plumbing shops

How our team Assembled Sieves?

How our team Assembled Sieves? - ProjectOxy

The above image represents a sieve that we used in the oxygen concentrator. So, basically this sieve contains two end caps (the two at the extreme ends), two meshes (green & pink ones), a spring, and zeolite.

The air-intake passes through the left-side end cap and then through the green-colored mesh. The zeolite between the two meshes filter out nitrogen from the air and oxygen-rich air then passes through the pink-colored mesh.

The holes of the pink-colored mesh are tinier than the green-colored one, As the pink-colored mesh has tinier holes, it allows to filter out dust particles of zeolite from the oxygen-rich air.

The oxygen-rich air passes along through the right-side end cap and continues its journey through the oxygen concentrator. This completes one cycle.

However, during a cycle, the whole setup (sieve and meshes along with end caps) gets pushed upwards by 1cm, due to high pressure, leaving it inoperable for the next cycle.

To solve this issue, our engineers placed a spring between the pink-colored mesh and the right-side end cap. This allows the sieve to settle down in its original position and relieve pressure. Relieving pressure allows the sieve to release nitrogen and process the intake air in the next cycle.

Dismantled Sieve - ProjectOxy

Above image depicts a better view of the parts used to build the whole setup.

Step1:-End Cap

End Caps - ProjectOxy
So here are the following steps our team had followed to create Sieve Bottom Cap.

A hole was created to fit the screw which was 10mm or 12mm smaller to thread and fix the nozzle (Push to connect Pneumatic connectors).

Inside of the cap they placed a same nozzle with copper screw (which can be purchased from any compressor shop or gas hardware shop) and fitted screw nozzle from inside of cap and glued it (ANNABOND Silicone Glue).

Here are the following steps our team had followed to create Sieve Top Cap.

Our team used the same procedure but here they used nozzle with elbow shaped pipe outlet on the outside of the cap.

Step2:- Filter

Here are some specifications our team followed to make the filter:

They used a thin pipe of 2.5 mm and glued it with a mesh (medium spaced mesh for bottom cap and very less spaced mesh for top cap).

Note:- Do ensure to have the diameter of filter little less than sieve as in order to fit it in.

2. Electronics

Our team also used the following things
  • AC to DC convertor with 12 v output 
  • Arduino Uno which acts as a mother board and controls the functions of all the electronic components
  • Relays to toggle the solenoids
  • Jumper wires

3. Pipes/chords

Our team also used 2 sizes of pipes which can be found in water purifiers.
  • PV ( Polyethylene tubing ) pipe of OD (outer diameter) – 10mm
  • PV pipe of OD (outer diameter)- 8mm
Note:- 10mm pipes are used in almost every connection, except in between 2 way solenoid valves as they are 3/8th of diameter of the pipe. So to connect 2 way solenoid pipes, our team used an 8mm PVC pipe (Polyethylene tubing).In order to connect all the pipes engineers used push to connect pneumatic connectors.

4. Air compressor

Initially our team planned to use a air compressor of 116PSI, 2.4 Hp and 300 LPM but due to lockdown we couldn’t get the required configuration so we had to settle down with next best alternative which was Air compressor of 116 PSI, 1.5 Hp and 200 LPM / 7 CFM.

5. Copper pipe Coolant

Note:- When ambient air is passed through the Air compressor,  it comes out as hot air. So  to cool down the temperature of air our engineers used copper pipe coolant.

6. Regulators

Our Engineers used the following:

  • High pressure regulator
  • Solenoid

The High Pressure Regulator was used to regulate the pressure to 35 psi from the 116 psi air compressor.

Solenoid is a simple valve which controls the input and output of compressed air that is directly connected to both the sieves.

In our case we had 2 solenoids which operated alternatively

Solenoids - ProjectOxy

10% of oxygen was sent to the container and the rest 90% of air was sent through 2 way solenoid via orifices.

Note:- After purifying oxygen, it is sent to the oxygen storage tank where it is stored at 20 psi.  Stored oxygen is supplied to the patient via a low pressure regulator and oxygen flow meter as required. As dry oxygen is harmful to humans, a humidifier was used to increase the humidity of oxygen and then it is sent to the Oxygen mask as final Pure oxygen .  

7. Zeolite

As Zeolite is used in this air compressor as it is highly absorbent of nitrogen, our engineers used 2 grades of Zeolite to test 5A and 13x

And I found out that 13X was a high grade Zeolite, mostly known as “Medical grade” Zeolite.

  1. Zeolite is the essential component of the concentrators which separates out nitrogen from ambient air under high pressure.
  2. There are varieties of zeolite used for multiple purposes; for concentrators we are using medical grade 13X Zeolite.
  3. There are independent distributors of 13x grade zeolite on Indiamart
  4. Alternatively, you can use lower grade zeolite (5A)
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