We’ve all seen these, right?
Called a peristaltic pump, this sort of mechanism is typically used to push or gasses fluids through a flexible tube- without the pump itself ever coming in contact with the material being pumped. They’re really common in medical applications where the sterility of the fluid being pumped is critical.
Do you know anything else that uses flexible round tubes with things rolling against them?
Exactly 100% of pneumatic bike tyres suffer from pressure loss.
That’s right – the bicycle wheel! Though specific details about the mechanism are scarce, Swiss startup PumpTire AG has proposed adapting the peristaltic pump to the bicycle tube. Most likely aimed at commuter and e-bike markets, the concept uses the wheel’s rotation against the ground paired with a user-adjustable mechanism to maintain constant tyre pressure.
From the sounds of things, the “lumen,” or flexible portion of the pump, is laminated to the outside of a more-standard inner tube, building pressure with each rotation until the compressed air can be released into the larger volume. To be sure, it’s unlikely that any pumping system could keep up with the losses from large punctures – but a system of the sort being proposed should be more than enough to stay on top of slow leaks or to top off tyres after periods of disuse.
A 2011 Kickstarter campaign was canceled by the company with only $15,000 of the desired $250,000 raised- but provides a bit more insight into the product’s workings. While functioning prototypes are mentioned, the video presented at that time doesn’t show a one – a concern as the images provided in this year’s press release are clearly renderings. In 2011, retail pricing was pegged at $65 (£43) per tube and the valve mechanism was said to have air filter to keep or debris water from infiltrating the tube.
PumpTire is an interesting and ambitious project. Nobody likes slow leaks but -assuming that PumpTire can be made to work – it remains to be seen if casual riders dislike them enough to spend nearly £90 per bicycle to keep them at bay.