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UJ develops 3D-printed ventilator to treat multiple patients

Read time 3min 40sec
From left to right: Damon James Hoenselaar, assistant designer; Prof Tien-Chien Jen, project lead; Dr Nkosinathi Madushele, 3D printing and coordinator; Rigardt Alfred Maarten Coetzee, lead designer; and Malcolm Low, electrical and ECSA student.
From left to right: Damon James Hoenselaar, assistant designer; Prof Tien-Chien Jen, project lead; Dr Nkosinathi Madushele, 3D printing and coordinator; Rigardt Alfred Maarten Coetzee, lead designer; and Malcolm Low, electrical and ECSA student.

The University of Johannesburg (UJ) is stepping up the fight against COVID-19 using 3D printing.

Engineers at the university have designed and developed portable 3D-printed mechanical ventilators that have a customisable base plate to treat multiple patients.

The innovation comes as South Africa’s COVID-19 cases have breached the 200 000 mark, while the death toll sat at 3 502 at the time of writing this morning.

As the pandemic continues to spread in SA, UJ says the country faces a looming ventilator shortage.

The UJ’s ventilator, named Aura Imprimere, meaning “A Breeze of Air Provided by Printing”, is portable and allows off-grid operations for up to one-and-a-half hours, says the university.

UJ has been at the forefront of using 3D printing to fight the coronavirus.

In April, the institution of higher learning created open source, cheap ventilators to help fight the COVID-19 pandemic.

During the same month, UJ’s Library Makerspace division developed 3D-printed surgical face shields, in an effort to meet the rapidly growing need for personal protective equipment for healthcare workers.

The university now joins tech companies such as Xerox and HP, which are also using 3D printing tech in the fight against the deadly virus.

HP is working with Johannesburg-based Mentis 3D to increase production of 3D designs to meet the most critical needs.

Globally, copier company Xerox is producing inexpensive, disposable ventilators that could serve as a critical stopgap for hospital-grade ventilators now in short supply.

Now, with Aura Imprimere, professor Tien-Chien Jen, UJ’s head of department of Mechanical Engineering Science and project team leader, says the ventilators are safe to operate.

“These unique 3D-printable ventilators use a microcontroller to control the operation of the two motors. By adjusting the speed and direction of rotation of the motors, it is possible to obtain a pressure-time profile that is suitable for respiratory assistance of patients.”

He explains that Aura Imprimere has a battery system that will ensure normal functioning while the demand for electricity exceeds the available supply.

“Its components are designed in such a way that it can be easily assembled, on site in cities, rural areas, or remote areas,” says Jen.

“The microcontroller monitors the pressure inside the Ambu bag by using a pressure sensor. If the pressure sensor picks up irregularities in the pressure, then the motor controller will intervene to correct these issues.

“It is also important that the mechanical arms of the ventilator operate in unison. Sensors that monitor the position of the ventilator arms are also used to enable the microcontroller to keep the mechanical arms of the ventilator in sync,” Jen explains.

According to the university, Aura Imprimere is based on a reciprocating engine piston and crank design.

It points out the motors were extracted from locally bought electric screwdrivers.

The ventilator allows for electronic components, such as a control resistor, variable resistor and a small programmable computer, to be used.

These electronic components can customise the pulse needed for the patient and can vary the speed of the pulsation.

The crank design provides a linear motion for the slider relative to the slider base, says UJ, adding that here the “fingers” are integrated that pushes the Ambu bag and allow it to deflate. The design is such that the friction between moving parts is minimised, it notes.

The UJ-led team plans to distribute the active breathing circuit system on an “open source” basis, making the software and designs freely available and allowing them to be produced anywhere in the world, provided the producers own a 3D printer.

Jen says the design by which the Ambu bag is placed as the centre component of the design is secured with clamps.

“The Ambu bag comes in different sizes, and the invention can be custom changed with ease, on site, according to the patient age, condition and breathing necessity.

“This is due to the meshed base plates that allow the clamps, mechanism, electrical housing, etc, to be re-oriented and placed as the consumer pleases,” he concludes.

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