Driven by an impending shortage of ventilators, TU researcher Gerwin Smit looked for inspiration at a classic machine that had proven its merit.
Smit found an English ventilator from the 1960s in the collection of the Boerhaave Museum in Leiden. It was the East-Radcliffe Positive-Negative Respirator. Museum Director Amito Haarhuis not only gave Smit permission to take the machine to Delft, but also to take it apart. “It is a sturdy machine that was built from readily available parts,” said Haarhuis. He points at the pressure cooker that humidifies outgoing air, and a bicycle gear hub that allows the machine to ventilate at different speeds. A stack of weights on the bellows sets the outgoing pressure.
After about a week, the 40 person team from Project Inspiration had rebuilt the old machine with new parts, including a shiny new gear hub. Next, they built a more modern prototype that is driven by an electric motor with variable speed. So the gear hub was gone, but the pile of weights and the pressure cooker remained. They also added new valves.
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The final apparatus has been fitted in a white box under a Plexiglas cover. Every part has been kept as simple as possible. The purely mechanical ventilator driver doesn’t require electronics. Biomechanical engineer Gerwin Smit thinks that hospitals in the Netherlands will not be needing this ventilator. But the publicly accessible specifications will allow people in low and middle-income countries to build ventilators locally.
Boerhaave Director Haarhuis couldn’t have imagined that modern engineers would call on last century technology, but he does see their project as a confirmation of the value of historic collections of medical technology.
