Preliminary Insights & Research

In March 2020, when the world was hit by COVID19 - Maker’s Asylum started the M19 Initiative to support the front line workers with medical grade equipment. The project started with making faceshields inside a makerspace and slowly grew into a large movement of distributed manufacturing when the team open sourced their designs in order to activate over 42 cities, towns and villages in India to make faceshields locally for their local hospitals. Then they went on to work on various other medical grade devices and during the second wave in April 2021 they worked on Oxygen Concentrators and activated over 150 organisations to make them locally in India via the same principles of open sourcing the design and decentralised manufacturing. During this time India was importing large amounts of oxygen concentrators from other countries including China, USA and France. In Goa, the Rotary Club of Margao had procured oxygen concentrators as part of their CSR to donate to hospitals and a few hundred of them had stopped working. In June 2021, the team at the Rotary Club reached out to Maker's Asylum to understand if they could help them fix these broken oxygen concentrators. That’s when they started working on understanding if there are many more such cases in India and floated a small request sheet to procure data from a few hospitals in different parts of the country. 

Following were the initial requests of repair received by the Maker’s Asylum team : 

Location

Broken Oxygen Concentrators (#)

Sant Kabir Nagar, Uttar Pradesh

2

Pune, Maharashtra

18

Margao, Goa

20

New Delhi, New Delhi

15

Hyderabad, Telangana

5

Colva, Goa

5

Jamtara, Jharkhand 

5

Dar es salaam,Tanzania

20

TOTAL

90

This data led to the realization that it is a possibility that there were many more oxygen concentrators that did not work inside hospitals and if there could be a way to help local communities learn about repair and help fix these.

Results from Repair Cafe : 

As part of the next steps, 3 repair cafes were hosted. 2 physically at a makerspace or a fablab and 1 virtually over an online meeting with individuals, makerspaces, and organisations from different parts of the world. 

1. Repair Cafe in Goa 

Date

19th & 20th October 2021

Location

Maker’s Asylum, Moira, Goa (Makerspace)

Broken Oxygen Concentrators Received

7

Concentrators Fixed

5

Number of participants 

10

Subject Matter Experts

2

General Issues 

Incorrect design of compressor mounting. It was not designed to handle transportation damages hence needed to be mounted properly for the oxygen concentrator to function

Cause for not able to fix the 2 oxygen concentrators

The compressors were completely broken and needed replacement. Hospital was informed to call for new compressors. 

2. Repair Cafe in Pune

Date

30th & 31st October 2021

Location

DIY Lab at Vigyan Ashram, Pune (Makerspace)

Broken Oxygen Concentrators Received

18

Concentrators Fixed

0

Number of participants 

20

Subject Matter Experts

3

General Issues 

Poor Material Used in Design - Zeolite Sieves End Caps were made out of plastic and were breaking because of stress and causing oxygen leakage in the concentrators. 

Cause for not able to fix the 18 oxygen concentrators

Needed redesigning with metal parts for the Zeolite end caps to not break. 

3. Virtual Repair Cafe

Date

10th of December 2021

Location

Online

Agenda

To share insights and knowhow on how to fix an oxygen concentrator

Number of participants 

30

Designed for 

Makerspaces, Fablabs which can act as conduits to the Right to Repair movement in different parts of the world and can also skill communities to help repair and reuse

Participant Profiles

Testimonials by participants

Anindya Mukherjee - DIVE Instructor, Goa Aquatics 

I do a lot of servicing of compressors, regulators, and all related equipment to Scuba Diving. So what Makers are doing is very similar to me, we use molecular sieves, compressors in diving as well. What I think is that we can train even the Margao Rotary Club people to fix these oxygen concentrators now and that way they can become independent in resolving more of these issues. 

Gorbachev Anthony - Founder, Parvai Aerospace

I have been working on making my own oxygen concentrator as part of the M19 Initiative and personally I believe that repair is very integral to making. Making and fixing are two parts of the same coin. So these repair cafes are very effective in sharing that knowledge quickly with others and the results are immediate. 

Yogesh Kulkarni - Director, Vigyan Ashram 

I have been running a rural fablab for over a decade now and teaching people how to make things using the least amount of resources. I was also very excited to host the repair cafe in our lab in Pune and my team and I learned a lot during the exercise. We are makers but getting the  insights from Anool & Vaibhav helped us get up to speed very quickly. We hope to teach more and more people how to fix them now. 

Ronak Sutaria - Founder & CEO, Respirer Living Sciences 

In the overburdened medical segment, I think there is a big role for this kind of community based distributed device makers. People who understand the technical concepts but are able to simplify so that the community can get involved. I think its an important role that makerspaces are playing. 

Dheep Caldeira - Car Modification Expert 

The repair cafe in Goa has been an incredible experience for me. I  love cars and upgrading them and as part of my daily life I am fixing and repairing all the time. I have never worked on an oxygen concentrator before but when I was there I could draw parallels into fixing cars. Which made me think about how effective this exercise could be if we involved mechanics and technicians to do the same. 

Aaditi Kharade, Innovation Hub Associate - Vigyan Ashram 

I am Aaditi Kharade,I have completed my B.E.in Electronics & Telecommunication in 2015. I have joined Vigyan Ashram,Pabal to improve my knowledge and confidence by doing things handson.I like to do innovative things,I have a learning attitude. I believe that updating ourselves with your growing era makes your life peaceful and this workshop really helped me learn something new. 

Pooja Jadhav, Project Instructor - Vigyan Ashram 

I am working as a computer lab instructor in Vigyan Ashram, India. I have taken a different workshop on 3D design and printing at different IBT schools. I have an interest in learning advanced technology in Digital Fabrication. Fab lab is a perfect place to learn  these things. Always I am ready to learn new technology. The repair cafe helped me also learn more about why we need to repair products and how it relates to waste. 

Anuj Deshpande, Makerville

I like learning about new things and I have been following Maker’s Asylum’s work during the pandemic. I think the progress from making oxygen concentrators, to sharing that knowledge with others to make them, to now skilling more people on how to fix them is a great progress of the project. It shows why sharing and collaboration is important especially when the planet is at risk.

Anurag Kataria, Yun Solutions 

I am not a maker. I can execute things. In the first lockdown I was helping few organisations to procure faceshields and realised that there was no availability in the market. I did not know how to help then. But then I saw the M19 designs, got them made in Pune and gave a few thousands to the hospitals. Oxygen concentrator to make would be very difficult for me but I thought repair is easier to learn. So the repair cafe was good like that. 

David Desouza, Photographer 

I take pictures for a living and like working underwater. So a lot of times I have designed and made things to work as per what I need. I wanted to learn how I can fix my own oxygen concentrator and hence came to the cafe. At the end we fixed it so it was a successful repair for me. Was great to learn from makers and experts and Maker’s Asylum is a great space for community to gather as well.

Previous work on building the M19O2 - Open Source High Flow Oxygen Concentrator

The M19O2 Oxygen Concentrator is an open source hardware project based on the well proven "Pressure Swing Adsorption" process, and inspired by the several other similar projects such as - OxiKit, OpenOx, Marut, RepRap and Project Apollo platforms.

This Data Sheet has brief details of the concentrator.

This Instruction Manual provides user specific instructions.

A detailed Assembly Manual is still work in progress and the link will be posted here soon.

Meanwhile, the M19O2 Git repository has all of the latest information needed to build and replicate the device - check the /engineering folder.

  1. VERSION 1 (α alpha prototype)
    1. The purpose of this prototype was to understand how the PSA cycle works, the parameters that affect its performance and efficiency, and identify shortcomings in the design. 
    2. The Oxikit design uses easily available PVC plumbing components attached to a wooden and plywood frame. This makes it cheap, but also unsuitable for use in hospital / medical environments where wood and PVC parts are deprecated. 
    3. The PVC sieves need a large number of parts which are glued together. PVC sieve assembly is a tricky process and results in leaking sieves which are prone to failure under pressure. The sieve construction also creates a very large void space at both the ends which affects performance.
    4. The molecular sieve zeolite material used is Sodium 13X. This has a relatively lower N2 adsorption capacity, which means building much larger sieves and using higher compressor pressure. 
    5. The Oxikit design has copper cooling coils to lower the temperature of the air exiting from the compressor, but it does not employ any moisture separation stage. 
    6. A large part of India has pretty high humidity throughout the year, with coastal locations having as much as >92% rH humidity. This high humidity severely affects the efficiency of the zeolite since it adsorbs moisture more than N2, but does not de-absorb moisture easily (requires an expensive, time consuming regeneration process). 
    7. This causes a gradual, irreversible reduction in oxygen generation capacity of the machine. The lack of real time oxygen concentration measurement is a major drawback too. 
    8. On the electronics side, the Oxikit code is based on the Arduino platform, and uses blocking “delay” statements to run the timing cycle. This is very inefficient since the microcontroller cannot be used simultaneously for other purposes such as oxygen measurement or safety and sensor interfaces. 
    9. These shortcomings resulted in Version 1 producing O2 at 5 lpm and concentration between 60~70% which was way below our target requirements. After a month of trying to incrementally fix  these issues, it was decided to abandon any further effort in improving the Oxikit design and get back to the drawing board for a fresh look.
  2. VERSION 2 (β Beta prototype)
    1. For Version 2, we decided to switch from Sodium 13X to Lithium LiX zeolite. LiX is three times more efficient compared to Na 13X making it easier to reach target requirements. By optimising the design, it was possible to offset the higher cost of LiX by reducing the cost of the BoM. Based on the learning from Version 1, we also made several other important improvements. Version 2 was built on an aluminum extrusion frame with acrylic parts. To achieve higher output flow rate, a more powerful compressor was used. The PVC sieves were replaced with machined aluminum sieves which were more robust, compact, and had very little void space at the ends. The problem of high moisture content in the compressed input air was tackled by adding a moisture separator with auto-drain mechanism after the cooling coils. An additional canister of desiccant was added after the moisture separator to further reduce the moisture content in the compressed air. This stage was experimental to try out different desiccant materials and monitor their effect on machine performance. An inline temperature and humidity sensor was added to obtain data. To fine tune timing cycles and optimise machine throughput, a LabView test bench was specially developed. This allowed real time adjustment of timing cycles without the need to reprogram the micro-controller. To allow monitoring oxygen concentration, an in-line oxygen sensor was added with alarm notifications. Results were promising. We managed to reach >90% concentration at about 8 lpm.
  3. VERSION 3 (Γ Gamma prototype)
    1. Version 3 was a test bed where we tried out various experimental configurations for getting deeper insights. The frame design and layout was refined. Sieve canisters were redesigned with a simpler end cap design and larger volume to help produce >90% concentration at 15 lpm. For moisture control, we tried three different setups. Two were based on refrigerant based chiller systems while the third was a PSA based moisture removal system. Chiller based systems work quite well for de-humidification, but suffered from pressure loss which impacted performance, Besides, they had a higher energy consumption and were more bulky making them unsuitable for use with a mobile O2 concentrator. The PSA based moisture removal system worked surprisingly well. It functions similarly to the O2 concentrator PSA, but the pneumatic circuit and timings are quite different and it is fairly compact. 
    2. Improved code using “millis” (non-blocking) instead of “delay” (blocking)
    3. Value engineering - reduction of parts

  4. VERSION 4 (Δ Delta prototype)

    1. Aluminum / acrylic / Al composite panel (ACP)  frame
    2. Aluminum sieves
    3. LiX zeolite
    4. Simplified moisture separation
    5. Custom designed sieve assembly
    6. Improved cooling
    7. Safety over-pressure switch to turn off compressor