3D-printed activated charcoal inlet filters for oxygen concentrators: A circular economy approach

Abstract

As of May 2021, the current COVID-19 pandemic is still plaguing the world, challenging all the countries and their health systems, globally. In this context, conditions typical of low-resource settings surfaced also in high-resource ones (e.g., the lack of essential medical equipment, of resources etc.), while exacerbating in the already resource-scarce settings, because of COVID-19. This is the case of oxygen concentrators that are one of the first-line medical devices for treating COVID-19 patients. Since the beginning of 2020, their demand has been rapidly growing worldwide, aggravating the situation for low-resource settings, where the availability of devices providing oxygen-enriched air was already scarce. In fact, due to their delicacy, the lack of spare parts and of an appropriate health technology management system, oxygen concentrators can often be found broken or not working properly in these settings. The underlying problems have deep roots. The current regulatory frameworks and standards, which are set by high-income countries, are too stringent, and do not take into account the limited resources of poorer settings. Thus, they are often inapplicable in such settings. One of the main issues affecting the oxygen concentrators, is that related to the filters, which are designed to filter out dust, particles, bacteria, and to be used in medical locations complying with international standards (e.g., the air filtration level in a surgical theatre in Italy is at 99.97%). When used in low-resource settings, which do not comply with these standards and face several challenges (e.g., dust), these filters have a much-reduced lifespan. For these reasons, this paper aims to present the redesign of the inlet filter of an oxygen concentrator, which is used to prevent gross particles to enter the device. The redesign is based on a reverse engineering approach, and on the use of 3D-printing along with activated charcoal. After testing the filtration efficiency with a particle counter, the filter design has been refined through several iterations. The final prototype performs particularly well when filtering particles above 1 μm (with a filtration efficiency of 64.2%), and still has a satisfactory performance with any particle size over 0.3 μm (with a filtration efficiency of 38.8%). Following the United Nations Sustainable Development Goals, this project aims to empower local communities, and start a positive trend of self-sustained supply chain of simple spare parts for medical devices, leveraging on frugal engineering, 3D-printing, locally produced activated charcoal, and circular economy.

Recent trends in the nanozeolites-based oxygen concentrators and their application in respiratory disorders

“…To better understand the pressurization and depressurization processes taking place inside the microporous region of nanosized zeolites, a simulation of the pressure and vacuum swing adsorption units was devised ( 92 ). Besides this, several investigators have also reported the surface modification of such nanozeolites by other metallic particles to make the process more efficient ( 1 , 97–99 ).…”

“…Oxygen is the basic requirement for both a healthy and a diseased individual. There are certain medical diseases, especially cardiovascular respiratory disorders, where there is a requirement for pure or concentrated oxygen by the patient ( 1 , 2 ). This pure or concentrated oxygen is indeed known as medical oxygen, and in the absence of it, a patient may experience hypoxemia [low levels of oxygenated blood ( 3 )].…”

Hypertension Diagnosis and Management in Africa Using Mobile Phones: A Scoping Review

“…Pending further validation, this system could be suitable for incorporation into a diagnostic tool such as an application for use on a mobile phone. Similarly, Ellis et al [64] presented the redesign of the inlet filter of an oxygen concentrator. The redesign is based on a reverse engineering approach, which makes use of activated charcoal coupled with 3D-printing methods, to accommodate environmental conditions that present in many African countries.…”

Design of a syringe extension device (Chloe SED®) for low-resource settings in sub-Saharan Africa: a circular economy approach

“…Over the past century, healthcare provision in low-resource settings (LRS) in sub-Saharan Africa (SSA) has been hampered by underfunded healthcare infrastructures ( 1 – 3 ). This results in a lack of medical devices crucial to provide healthcare for all ( 4 , 5 ).…”

“…Presumably, this high volume of donations should drastically improve the availability of functioning medical devices in LRS ( 3 ). Nevertheless, these initiatives have been estimated to be unsuitable and unsustainable ( 3 ). Estimates suggest that about 40% of medical devices donated are non-functional, thus leaving healthcare facilities in LRS with the issue of medical device unavailability and excessive waste streams of defunct devices ( 10 – 12 ).…”