COVID-19: IISc team building ventilator prototype using local parts

As the clamour for medical ventilators reaches a fevered pitch amid the escalating COVID-19 crisis, a group of IISc scientists and students have been working night and day to develop a high-quality indigenous ventilator which makes use of sensors and parts sourced from the local automotive and RO water filter industries.

"The idea is to circumvent a shortfall of internationally imported components which are holding up the mass manufacture of ventilators in the country,” said Associate Professor Gaurab Banerjee of the Indian Institute of Science’s (IISc) Electrical Communication Engineering Department, a brainchild behind the invention.

“In a worst-case scenario, about 0.006% of COVID-19 cases will require critical care with access to ventilators. For a population of 130 crores, this translates to about 70,000 patients,” he added.

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The prototype is designed to make use of materials which are readily available in India and in large numbers such as pressure sensors used in cars and solenoid filter valves in Reverse Osmosis (RO) water filters.

According to the team, the plan is to take a pressurised mixture of medical-grade oxygen and compressed air, and mix it using food-grade containers and tubing found in domestic RO water filters. A programmable logic controller (PLC) board and a Raspberry Pi computer will control the air pressure, the oxygen composition and flow characteristics.

The challenges have been steep. At the heart of ventilator technologies are mass-flow sensors and controllers which accurately tell you (and control) how much oxygen is flowing through and what volume of oxygen the patient is inhaling in one breath. These are commonly imported from Switzerland.

The team said it has now duplicated that technology using automotive-grade sensors and solenoid valves by using basic principles of fluid mechanics and gas dynamics and has verified the results experimentally.

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"By using these checks, we are able to work out what this oxygen concentration should be and what the flow rates are," explained Associate Professor Duvvuri Subrahmanyam, of IISc’s Department of Aerospace Engineering who said that similar flow physics is at play in high-speed flight and rocketry.

The prototype, which has been in development for 14 days, is expected to be completed by the end of April. Professor Banerjee explained that the team has set itself five milestones before the prototype can be deemed complete.

"On Friday, we completed the second milestone, which was to combine pneumatics and an industrial controller to time-cycle air-flow," he said.

Among those reportedly evincing interest in mass manufacturing the prototype is Bharat Heavy Electricals Limited (BHEL). The team clarified that they were ready to transfer the technology free of cost to any interested parties.

"What we are building is completely open-source. Anyone can use it. This is a bid to save our people," said Dr T V Prabhakar of IISc’s Department of Electronics Systems Engineering.

Project Praana (as the group calls itself) also comprises Assistant Professor Pratikash Panda of the Department of Aerospace Engineering, Professor H S Jamadagni from IISc’s Department of Electronics Systems Engineering, a Bengaluru-based engineer, Manas Pradhan, an IISc alumnus, plus 100 volunteers from IISc and around India.