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Measuring flow rate and purity in portable oxygen concentrators


For people with respiratory disorders who need additional oxygen therapy, oxygen concentrators are vital medical equipment. By concentrating oxygen from the ambient air, they function to give the user a greater flow of oxygen-enriched air. The application of lithium zeolite for oxygen concentration in POCs is the most intense part of this work. One kind of zeolite material that may selectively absorb nitrogen from the air to increase oxygen concentration is lithium zeolite. The capacity, effectiveness, and dependability of a POC fitted with lithium zeolite are all examined in this study, along with its overall performance. The findings show that lithium zeolite, which has benefits including high oxygen purity and low energy consumption, is a potential material for use in POCs. The results of this study aid in the creation of POCs for oxygen therapy that are more effective and efficient. This study suggests utilizing an Arduino microcontroller and an HX710B air pressure sensor to measure the oxygen flow rate in a POC. The POC’s oxygen flow channel incorporates the HX710B sensor to monitor pressure variations, which the Arduino uses to translate into flow rate readings. To verify the accuracy and dependability of the system, its performance is assessed under different flow rate scenarios. Lithium zeolites are well-known for having a high selectivity for nitrogen adsorption, which can enhance the concentrator’s oxygen separation process’s effectiveness. Lithium-zeolite-based oxygen concentrators may have a lower environmental effect than standard concentrators.


To help them with their breathing challenges, people with chronic obstructive pulmonary disorders (COPD) rely on portable oxygen concentrators. To ensure patient safety, these devices must deliver the proper amount and quality of oxygen extracted from the air. An alternative that is non-intrusive and possibly less expensive for monitoring these parameters is provided by air pressure sensors. The viability of measuring oxygen purity and flow rate in an oxygen concentrator was examined using air pressure sensors. Create a system to track these variables in real time using an air pressure sensor and an Arduino microcontroller. Enhance the functionality of portable oxygen concentrators by making sure that oxygen is delivered precisely. Provide an affordable, non-intrusive method for measuring airflow in a variety of contexts, such as industrial, medical, and environmental ones.


There is significance of purity and flow rate indicators in portable oxygen concentrators for guaranteeing that patients receive the appropriate oxygen dosage at the appropriate purity levels. Important details are highlighted, including the percentage of pure oxygen, the flow rate expressed in liters per minute (LPM), the use of sensors for measurement, the need for upkeep and observation, and the application of alarms or indicators for safety and maintenance alerts.


Airflow measurement is taken convenient by the easy addition of sensors to current models. When compared to current techniques, sensor data exhibit excellent accuracy, which facilitates improved troubleshooting and optimization. There are opportunities for monitoring and even optimizing therapy when sensors are connected to an Arduino. Broader uses for this technique include monitoring industrial operations and respiratory parameters in patients. An early identification of problems and improved management of oxygen therapy could result from more precise monitoring. Reusable, non-intrusive sensors may cut down on waste and the expense of calibration. More people may be able to receive oxygen treatment if monitoring is made easier. The monitoring technique could be modified for use in a variety of industries where exact airflow control is necessary. Lithium zeolite is a stable material that can be safely utilized in oxygen concentrators, lowering the danger of combustion and other hazards associated with oxygen-rich settings.


Oxygen concentrators are medical devices that extract air from the room, separate the oxygen from other gases present, and deliver oxygen to the patient. It is efficient and reliable, providing oxygen for many individuals. Oxygen concentrators can provide a continuous supply of oxygen without the need for refills or replacement tanks, making them convenient for long-term use.

SS conducted a study on the utilization of lithium-based 13X zeolite and sodium-based 13X zeolite in various sizes to produce oxygen. They confirmed the oxygen purity, flow rate, and pressure through analytical and quantitative methods. An oxygen concentrator was used in a study by GAP to meet the oxygen therapy needs of the patients. They worked out the best time to open and close the gate valve in order to control the flow of oxygen. VK investigated the use of nanotechnology for efficient oxygen synthesis using oxygen concentrators. They focused on nanoparticles (NPs) with sizes typically under 100 nm, which possess a high surface area-to-volume ratio, enhancing their effectiveness as oxygen adsorbents. YB contributed to a study where nanozeolites were used as replacements for molecular zeolites in oxygen concentrators to enhance oxygen delivery efficiency. NS analyzed an article that explored green, resilient, and responsive elements, considering economic, environmental, and resilience aspects, in constructing a supply chain network for oxygen concentrators. RR conducted research on a medical oxygen concentrator device employing rapid pressure swing adsorption for uninterrupted oxygen supply. They utilized LiLSX zeolite to separate oxygen from compressed ambient air. The device’s performance was evaluated using a medium-sized air compressor independently, resulting in an oxygen product purity of 90%. LM contributed to a study on synthesizing zeolites from waste materials for medical oxygen concentrators. The study evaluated the use of low-cost waste materials, such as aluminum and silicon, for manufacturing NaX zeolites used in the design of medical oxygen concentrators. SR demonstrated that the incorporation of silica gel in oxygen concentrators leads to higher oxygen purity. ML analyzed thermodynamic models to optimize the mass, energy, momentum, and adsorption equilibrium of PSA oxygen generators. They evaluated the mathematical model of the LDF equation. GA showed that integrating oxygen concentrators with an IoT system enables monitoring of device users. MW demonstrated the application of CPAP machines for non-invasive lung ventilation with full-face masks. They conducted an evaluation using a portable pressure chamber and an oxygen concentrator. DS conducted a comparison and analysis of portable oxygen concentrators and inspired oxygen levels using a COPD patient simulation model. YS developed and evaluated a mathematical model for the rapid-cycle PSA process, focusing on achieving optimal performance with high oxygen productivity. KG proposed an innovative technique for remotely controlling the flow rate of oxygen concentrators, leading to improved patient control and safety. YY utilized pressure swing adsorption technology to identify potential risks and breakdowns in medical oxygen delivery systems, combining HAZOP and intuitive fuzzy logic. JC analyzed a portable oxygen concentrator with continuous and pulse-flow oxygen, examining the volume-averaged FIO2 at the trachea. CC proposed quantifying the efficiency and purity of pressure swing adsorption in producing oxygen compared to alternative approaches. IN conducted a study on an intelligent system that automatically adjusts oxygen delivery based on patient needs and respiratory conditions. AL investigated respiratory support treatment using a bubble-like mask to improve lung expansion and oxygenation. SO reported increased oxygenation, reduced hospital readmissions, and increased patient satisfaction with their approach. AT examined an affordable respiratory support approach using a blower-powered mechanical ventilation system. AF evaluated natural zeolites as an alternative to synthetic adsorbents for efficient and pure oxygen generation from air using PVSA technology. PC The flow rates and oxygen concentration capabilities of oxygen concentrators, ventilator capabilities, and three-way connector types were examined. AD discussed the use of pressure swing adsorption (PSA) technology in portable medical oxygen concentrators based on the quadrupolar interaction of zeolite with nitrogen molecules. SA evaluated the potential of an electrochemical oxygen pump using a solid polymer electrolyte (SPE) for efficient and portable oxygen synthesis. DB provided crucial evidence for enhancing health systems in low- and middle-income countries experiencing oxygen shortages through a probability proportional to size (PPS) sampling survey. SM suggested that oxygen concentrators (OCs) could be a viable alternative to traditional oxygen cylinders for improving access to oxygen in poor and middle-income countries. DM raised questions about the efficacy of portable oxygen concentrators (POCs) during sleep and exercise. DS compared the effects of two zeolite adsorbents, 13Xzeolite and a combination of 13X and Bayah zeolite (13X + ZAB), on the quality of oxygen produced using pressure swing adsorption (PSA). AA designed and optimized adaptable single-bed MOC systems with simulation-based optimization for PSA and PVSA technologies. MP explored the practicality and efficiency of portable oxygen concentrators for individuals with respiratory problems using a simplified PVSA cycle and nano-sized zeolite adsorbent. KO enhanced the performance of tiny adsorption-type oxygen concentrators using two zeolites and developed an analytical method for gas flow and temperature distribution in columns. AS explored the design of a portable medical device oxygen concentrator employing pressure swing adsorption (PSA) technology, suggesting LiXzeolite as a viable solution for efficient oxygen production. AD promoted the use of portable and hospital oxygen concentrators using Na-Xzeolites to deliver continuous oxygen flow to patients with respiratory demands. YB discussed the need to optimize PSA equipment and procedures and maximize oxygen production capability using zeolite. NS studied the impact of zeolite size, mass, and type on oxygen purity in an oxygen concentrator using the pressure swing adsorption (PSA) method and identified optimal settings for maximizing oxygen purity. FC developed and analyzed 3D-printed zeolite monoliths as a replacement for pelletized zeolite in oxygen concentrators in low-resource environments. LM explored the feasibility of using waste materials, specifically coal fly ash, for low-cost, sustainable zeoliteX (NaX) synthesis in African countries to enable the development of affordable oxygen concentrators. VK evaluated the possibility of using nanozeolites as a replacement for conventional molecules to improve oxygen yield and efficiency in oxygen concentrators. SA investigated the use of silica gel as an alternate filtration medium in portable oxygen concentrators to increase oxygen purity compared to regular synthetic zeolite. AP examined the effectiveness of the excavation process in enhancing oxygen concentrator performance versus the commonly used pressure swing adsorption technology. DS aimed to find the ideal flow rate for maximizing oxygen purity for both Zeolite13X and a combination of Zeolite13X and Zeolite Alam Bayah adsorbents. HH determined the best parameters for increasing oxygen and nitrogen purity in a pressure swing adsorption (PSA) unit with activated alumina as the adsorbent. YD aimed to create a portable, inexpensive, and effective oxygen concentrator prototype to address the crucial issue of oxygen access in various circumstances. HO identified and assessed additional NOx reduction techniques for further optimization and possible synergy. JB developed and validated a cost-effective, high-performance oxygen concentrator for patients with COPD using pressure swing adsorption (PSA) technology. YS created and evaluated a heat and mass transfer model for rapid-cycle pressure swing adsorption (PSA) air separation with tiny LiLS. X zeolite particles are to optimize the process for higher oxygen purity, recovery, and productivity. CC investigated pressure swing adsorption (PSA) technology as a competitive and versatile method for producing high-purity oxygen that meets both environmental and industrial objectives. MB developed a medical device using pressure awing adsorption (PSA) technology for point-of-care oxygen therapy in various settings, addressing the growing demand and resource constraints caused by the COVID-19 pandemic and limited access to oxygen in developing countries. MA developed a locally produced and configurable concentrator using a sustainable and efficient approach to meet the demand for accessible and affordable medical oxygen therapy.


The physical attributes and parameters of pure lithium zeolite are shown in Table 1.

Table 1 Physical properties of pure lithium zeolite

The technical details of the portable oxygen concentrator can be seen in Table 2.

Table 2 Technical specifications of portable oxygen concentrator

Lithium zeolite molecules are shown in Fig. 1; oxygen concentrators use lithium zeolite, more especially lithium X zeolite, because of its capacity to selectively absorb nitrogen from air, enabling the concentration of oxygen. With the addition of lithium ions to its structure, the chemical composition of lithium X zeolite is comparable to that of other zeolites. The general formula for lithium X zeolite is as follows: z is the amount of water molecules, while x and y are the ratios of silicon to aluminum in the framework. Applications involving oxygen concentration can benefit from the zeolite’s adsorption qualities.

Fig. 1
figure 1

Lithium zeolite molecular sieves

Lithium X zeolite’s general formula is represented as:

$${\text{Lix}}\left[ {\left( {{\text{AlO}}_{{2}} } \right)_{{\text{x}}} \left( {{\text{SiO}}_{{2}} } \right)_{{\text{y}}} } \right] \cdot {\text{zH}}_{{2}} {\text{O}}.$$

A pressure swing adsorption (PSA) oxygen concentrator is a device that increases the oxygen concentration in the surrounding air by selectively adsorbing nitrogen molecules using zeolite, a particular material that has a strong affinity for nitrogen. A summary of the schematics and descriptions is shown in Fig. 2.

Fig. 2
figure 2

Schematics of the PSA oxygen concentrator

Compressed air

The system first draws in ambient air, which is compressed by a pump. This raises the pressure of all the gas components in the air, including oxygen and nitrogen.

Zeolite beds

Compressed air moves through two compartments containing zeolite. Zeolite serves as a molecular sieve, selectively adsorbing gas molecules based on size and affinity. Zeolite has a high affinity for nitrogen molecules, trapping them on its surface.

Pressure swing

The “swing” portion involves reducing pressure in one of the zeolite beds. This allows previously adsorbed nitrogen molecules to desorb (re-release) from the zeolite, while oxygen molecules, which are not strongly attracted to the zeolite, remain unaffected.

Enriched oxygen

The remaining gas exiting this initial chamber is now much more oxygen than ambient air. After that, the enriched oxygen was collected and provided to the patient.


While one zeolite bed releases nitrogen, the other is still under high pressure, adsorbing nitrogen from the entering compressed air. This cycle of adsorption and desorption rotates between the two beds indefinitely, guaranteeing a steady supply of enriched oxygen.

Oxygen purity

Zeolite adsorption technology is used in oxygen concentrators where nitrogen from the air is selectively absorbed by the zeolite, enabling oxygen to flow through. The airflow rate through the concentrator is one of the elements that affect the zeolite’s capacity to absorb nitrogen. The amount of time that air and zeolite are in contact reduces as the flow rate rises. Because of the shorter contact duration, there may be less effective nitrogen adsorption, which would result in less pure oxygen in the output gas stream. To guarantee that the oxygen concentration is constant for the user’s demands, contemporary oxygen concentrators are made to maintain a high degree of oxygen purity over a range of flow rates. Lithium zeolite, a type of zeolite that contains lithium ions in its structure, is used in some oxygen concentrators due to its high selectivity for adsorbing nitrogen from air. Zeolites are porous materials with a specific crystal structure that allows them to selectively adsorb molecules based on their size and polarity. Lithium zeolite has a high affinity for nitrogen molecules, which are larger than oxygen molecules, allowing it to effectively separate nitrogen from air. In an oxygen concentrator, ambient air is compressed and passed through a bed of lithium zeolite. The zeolite adsorbs nitrogen molecules, allowing oxygen-enriched air to pass through. After a period of adsorption, the zeolite bed is depressurized, releasing the adsorbed nitrogen and regenerating the zeolite for another adsorption cycle.

Block diagram of pressure swing adsorption

Pressure swing adsorption (PSA) is a versatile process that separates gas mixtures such as air into different components, as illustrated in Fig. 3.

Fig. 3
figure 3

Pressure swing adsorption (PSA) technology


A pressured gas mixture passes through an adsorbent-containing column. Gas molecules with a higher affinity for the adsorbent will adhere to its surface, whereas the less strongly attracted molecules will travel through the column and escape as product gases.


When the adsorbent bed is nearly saturated with the required gas, the pressure in the column decreases. This causes the adsorbed gas molecules to desorb from the adsorbent and pass through the column as the purified product.


To prepare the adsorbent bed for another cycle, it is purged with a purge gas, such as air or another inert gas, at low pressure. This removes any remaining adsorbed molecules from the bed and prepares them for the next adsorption cycle.



Figure 4 shows that the compressor is the heart of an oxygen concentrator and is responsible for sucking in air, pressurizing it, and feeding it into the sieve beds. The compressor begins by sucking in ambient air from the surrounding area via an air filter. This filter eliminates dust, pollen, and other airborne particles that can harm internal components or disrupt the oxygen separation process. Once the air enters the compressor, it is swiftly compressed by a succession of pistons or diaphragms. This dramatically increases the pressure of the air, generally reaching 2–3 times that of the surrounding atmosphere. The compression process generates heat, which can damage the compressor and reduce oxygen concentration efficiency. To avoid this, oxygen concentrators use cooling devices such as fans or heat exchange to disperse generated heat and maintain proper operating temperatures. The compressed air then exits the compressor and is routed to the sieve beds, which are the main components responsible for separating oxygen from nitrogen. This compressed air is the driving force behind the separation process within the sieve beds.

Fig. 4
figure 4

Schematics of the proposed PSA oxygen concentrator

Exchange valve

The valve works in tandem with two independent zeolite sieve beds that contain a unique substance capable of selectively adsorbing nitrogen molecules from the air. During the adsorption phase, the valve directs compressed air from the compressor to one of the sieve beds. The zeolite substance in this bed traps nitrogen molecules, allowing oxygen-rich air to pass through and reach the patient. During the desorption phase, the valve switches positions, isolating the filled sieve bed and directing compressed air to the other bed. This produces a pressure difference that aids in the release of adsorbed nitrogen molecules from the previous full bed, preparing it for the next adsorption cycle. The alternating flow of air between the two sieve beds is controlled by the exchange valve, which allows for continuous oxygen production by the concentrator.

Combination valve

During adsorption, direct compressed air is added to the chamber containing the zeolite material for nitrogen adsorption. During desorption, separate ports are opened to generate a pressure difference within the chamber, allowing the adsorbed nitrogen molecules to be released and the bed to be prepared for the next sorption cycle. The primary exchange valve would still control the flow of air between the two sieve beds during the adsorption and desorption stages. When the oxygen pressure reaches a specific level, the integrated bypass valve opens, allowing some of the enhanced air to bypass the sieve beds and continue to flow to the patient.

Pressure regulator

The concentrator generates oxygen-rich air at a pressure higher than atmospheric pressure. The pressure regulator functions as a buffer, controlling the flow of oxygen to keep the pressure constant despite changing demand. This provides constant and uninterrupted oxygen delivery. The pressure regulator lowers this pressure to a safe and comfortable level for the patient.

Air tank

An air tank is prefilled with compressed air or medical-grade oxygen. This stored oxygen provides a limited supply until the tank needs to be refilled. Air tanks may deliver oxygen at higher flow rates than conventional oxygen concentrators, making them ideal for emergencies or individuals with high oxygen requirements. Oxygen concentrators are often large and require an electrical outlet to function; hence, they are best suited for home or stationary use.


The goal is to develop a modular and user-friendly device that improves the safety and comfort of oxygen therapy while simultaneously providing important health monitoring capabilities.

Portable oxygen generation

The concentrator extracts oxygen from the surrounding air using pressure swing adsorption (PSA) technology, ensuring a consistent supply of oxygen for the user.

Health monitoring

An HX710B air pressure sensor is used to monitor a user’s health parameters, such as respiratory rate or lung function, by monitoring air pressure in the user’s surroundings or within the respiratory system.

Safety enhancement

Real-time health monitoring can help assure the user’s safety during oxygen therapy by enabling fast action if any adverse health events occur.


By combining oxygen generation and health monitoring into a single portable device, users may receive oxygen therapy and health monitoring wherever they go, eliminating the need for several pieces of equipment.

Data collection

Devices may gather data over time and can then be analyzed or used to provide insights into the users’ health trends.

Practical implications

The practical implications of health monitoring in POCs are encouraging, but successful adoption necessitates collaboration among technology developers, healthcare providers, and regulatory organizations. To maximize the benefits for patients and healthcare systems, it will be necessary to address the problems described above and ensure the ethical and responsible use of ML algorithms.

Research limitations

Data privacy and security

Health monitoring devices collect sensitive personal information. Ensuring the privacy and security of sensitive data is critical and may necessitate additional precautions to comply with data protection rules.

Clinical validation

If the device is intended for medical use, clinical trials or studies to validate its efficacy and safety may be needed, which can be time-consuming and costly.

Environmental considerations

Creating a portable device brings about concerns regarding its environmental impact, including energy consumption, materials consumption, and end-of-life disposal.


Potential for personalized therapy

The combination of oxygen concentration and health monitoring could allow for personalized therapy depending on the user’s specific needs and health status, increasing the efficacy of oxygen treatment.

Compact and portable design

The integration of these technologies into a single portable device is revolutionary in and of itself. This design provides increased mobility and convenience for individuals who need oxygen therapy while on the go.

Integrated health monitoring

Although POCs are routinely used for oxygen therapy, the use of an HX710B air pressure sensor for health monitoring is uncommon. This integration enables real-time monitoring of the user’s health parameters, resulting in a more complete approach to patient treatment.

Table 3 shows the trade-offs between traditional and portable oxygen concentrators, with each kind suited for particular use cases and locations based on considerations such as mobility, power source availability, and user preferences.

Table 3 Comparison of different features measurements of oxygen concentrator technology, materials, capacity, size, and applications

The proposed prototype

Oxygen concentrators are medical devices that capture oxygen from the surrounding air and provide oxygen to patients who need supplemental oxygen therapy. Monitoring and enhancing patient functioning is critical for ensuring patient safety and providing the appropriate amount of oxygen. Air pressure sensors play an important role in this process since they provide data on several elements of the concentrator’s performance.

Flow rate

Air pressure sensors can be used to determine the rate of oxygen delivery to the patients. This approach is necessary to ensure that the patient obtains the appropriate amount of oxygen.


Sensors can monitor pressure within concentrator internal components, including PSA beds. These data aid in detecting potential blockages or leaks that could impair performance.


Air pressure sensors can indirectly determine oxygen purity by monitoring the pressure difference between ambient air and concentrated oxygen stream.

Figure 5 shows that an air pressure sensor module is a tiny device that detects the pressure of the air surrounding it. They are employed in a broad range of applications. The concentrator settings were adjusted based on the detected flow rate to ensure that patients received the prescribed amount of oxygen. Air pressure sensors are utilized in several medical devices.

Fig. 5
figure 5

Schematic of air pressure sensor module

The sensor module features a high linearity pressure sensor and a low-power, 24-bit apparent diffusion coefficient ADC with factory-calibrated coefficients. The device offers accurate 24-bit digital pressure and temperature readings, as well as customizable operation modes to optimize conversion speed and current usage.

Table 4 shows that the HX710B air pressure sensor module is an excellent solution for models that require precise and consistent measurements of low-pressure ranges, its adaptability, compact size, and low power consumption.

Table 4 Product specifications

Figure 6 depicts the basic connections between the oxygen concentrator and its important components. The concentrator was placed into a power outlet. The filter eliminates dust and particulates from the surrounding air, a unit that compresses the surrounding air. Chambers containing zeolite material separate oxygen and nitrogen. The valve controls the flow of air between the sieve beds. The output pressure of oxygen-rich air is controlled. There is a connection point for the nasal cannula or other oxygen delivery equipment.

Fig. 6
figure 6

Hardware for the proposed oxygen concentrator

Figure 7 shows the particular connection between the oxygen concentrator’s air pressure and the Arduino controller. Sensors used to measure air pressure (e.g., analog pressure sensors and pressure transducers). Wiring schematic demonstrates how the pressure sensor is connected to the proper analog or digital pins on the Arduino board and representation of how the Arduino would analyze and output the pressure data (for example, serial transmission and data visualization).

Fig. 7
figure 7

Hardware connection diagram of the portable oxygen concentrator and air pressure sensor connection to the Arduino controller

Figure 8 shows connecting the portable oxygen concentrator (POC) and an air pressure sensor (HX710B) to an Arduino controller is an intriguing and potentially powerful model for monitoring and regulating parts of oxygen therapy.

Fig. 8
figure 8

Interfacing portable oxygen concentrator and air pressure sensor with Arduino controller

Figure 9 shows a graph of the experimental findings for flow rate vs purity revealing the relationship between these two variables. A common experiment involves adjusting the flow rate and determining the purity of the produced oxygen.

Fig. 9
figure 9

Experimental results of oxygen concentrator flow vs purity

Figure 10 shows the trial findings of an oxygen concentrator’s flow rate versus its air output pressure allowing us to see how the device operates across various settings.

Fig. 10
figure 10

Flow vs air output pressure

Table 5 shows the table and graph of the experimental data for tidal volume, inspiratory time, and flow rate providing a clear picture of how these variables interact with one another and change under various conditions. These data are useful for determining respiratory function, improving ventilator settings, and assessing the efficacy of respiratory devices.

Table 5 Flow vs air output pressure


The flow rate can be changed to suit the individual needs of the patient. Although the purity of the oxygen generated can vary, oxygen concentrators function by extracting oxygen from the surrounding air. Medical-grade oxygen is typically expressed as being between 90 and 95 percent pure. The degree of purity can be impacted by variables like humidity, altitude, and machine upkeep. Sensors are used by oxygen concentrators to measure the purity and flow rate of oxygen. While oxygen sensors track the quality of the oxygen being created, flow rate sensors make sure the apparatus delivers the right amount of oxygen. To make sure the concentrator is operating properly, it is imperative to regularly examine the purity and flow rate. Maintaining the item by the intended parameters also requires calibration and upkeep. Indicators or alarms are frequently included on oxygen concentrators to notify users of problems with purity or flow rate. These alerts can support timely maintenance and patient safety. For patients with respiratory disorders to receive oxygen therapy that works, portable oxygen concentrators must be able to measure both purity and flow rate.


Portable oxygen concentrators need to measure both flow rate and purity to provide patients with the right amount of oxygen while preserving their safety and comfort. These values are often obtained using oxygen sensors and flow meters, and the concentrator’s control system uses the information to modify the amount of oxygen supplied. There is material of choice for portable oxygen concentrators (POC) because of its great selectivity and capacity for nitrogen adsorption. This means that less zeolite material is required to produce purer oxygen, which leads to a lighter and more compact POC design. It provides the highest oxygen purity (up to 95%) of all the materials used in oxygen concentrators.

Comparison with similar works

Lithium zeolite-based oxygen concentrators are smaller and lightweight than standard concentrators, making them ideal for portable use. The adsorption capabilities of lithium zeolite may allow for extended running hours on a single charge or refill, making portable oxygen concentrators more convenient and usable.


Zeolites are recognized for their high surface area and porosity, which can aid in the adsorption of oxygen. Lithium zeolite, in particular, has been examined for its capacity to selectively absorb oxygen from air, making it an attractive material for oxygen concentrators. Lithium zeolite can selectively absorb oxygen over nitrogen, resulting in oxygen-rich air. This can be useful in medical applications when higher levels of oxygen are required. The use of lithium zeolite in oxygen concentrators has the potential to increase energy efficiency by reducing the amount of energy required for oxygen separation when compared to conventional approaches. The HX710B sensor can be used to monitor the air pressure inside the oxygen concentrator, providing useful information for guaranteeing the device’s proper operation. By monitoring air pressure, the system can detect defects such as leaks or blockages in the oxygen flow channel, improving the device’s dependability and safety. The sensor can be used to ensure that the oxygen concentration delivered by the concentrator is within the required requirements.

Future research work

Implementing innovative control systems that use data from the HX710B sensor to dynamically change the oxygen generation process based on real-time pressure monitoring, assuring peak performance and safety, continued attempts to miniaturize and lightweight POCs can make them more portable and comfortable for users, increasing their applicability in a variety of scenarios. Long-term reliability studies are being conducted to assess the durability and performance of POCs based on lithium zeolite and the HX710B sensor under a variety of operating settings and environments, exploring the integration of POCs with Internet of Things (IoT) technology for remote monitoring and management, allowing healthcare personnel to remotely monitor patients’ oxygen therapy and alter settings as needed.

Availability of data and materials

Not applicable.



Portable oxygen concentrator


Chronic obstructive pulmonary disease


Liters per minute


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I want to sincerely thank Dr. J. Jayakumar and Dr. P. Subha hency jose for their early guidance. I want to express my gratitude to the technical staff in our division. Indian Council Medical Research (ICMR), located in New Delhi, India, provided funding for this study. The authors would like to thank those who helped with this research.


The authors would like to acknowledge the support provided by the Indian Council of Medical Research for supporting this research.

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Author Contribution Statement for the manuscript “Measuring Flow Rate and Purity in Portable Oxygen Concentrators”, by S. Vijai, J. Jayakumar, and P. Subha Hency Jose, formulated the control problem and implemented the hardware. “JJ provided supervision for the project, conceptualization, formal analysis, funding acquisition, project administration initiated the key ideas for real-time control and guided the implementation. PS provided data curation, formal analysis, investigation, software for running the control algorithm, writing—review & editing and tested it on the experimental system. SV provided guidance in running the PSA process and assisted in assembling the hardware implementation. All authors read and approved the final manuscript."

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Correspondence to Vijai Sivalingam.

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Sivalingam, V., Jayaraj, J. & Paul, S.H.J. Measuring flow rate and purity in portable oxygen concentrators. Bull Natl Res Cent 48, 58 (2024).

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