Engineering news
FloSTEM, created by Hampshire-based firm 3form Design, is the size of a golf ball, and uses a tiny in-built gearbox to allow consumers to control and monitor their domestic water consumption without the need for an app.
The device is designed to be installed between the shower pipe and shower-head, or between a tap and a hosepipe. When 45 litres of water has passed through the device it shuts off the flow of water until the user presses a button on the side to allow the next 45 litres through.
“Many water saving devices limit usage by measuring time rather than volume, so people are left with no real understanding of how much water they’re actually using,” said Ally Le Sueur, operations manager at 3fD. “The ones that do measure volume are often expensive devices with integrated electronics and apps.”
An average eight-minute shower uses 65 litres of water, while a bath uses 80 – so by setting the shut-off point at 45 litres, FloSTEM seeks to make users more aware of how much they’re consuming. The device works using an impeller, which rotates as water passes through it, driving a specially-designed fixed ratio gearbox that triggers the shut-off mechanism when 45 litres of water has passed through it.
The gear ratio required was 262,000:1, and the device had to be cheap and able to fit through a letterbox. The company prototyped their gearbox, which uses an ‘epicyclic’ design and is made from plastic, using 3D printing.
“We chose to use an epicyclic gearbox because they can be made really compact and can reach the very high ratio that we needed to make the device work,” said Simon Willis, a product designer at 3fD. The final gearbox has many nuances to make it work especially for FloSTEM and it’s certainly the smallest gearbox that we’ve ever come across.”