Kamstrup started with a sandbox setup in the company’s own back garden where they could test a string of prototypes. Here, the development engineers from Kamstrup and Operational Assistant from Skanderborg Utility, Frank Nielsen drilled holes in test pipes – and listened.
”We spent a lot of time filtering the sound – recognising and eliminating noise sources such as traffic, a washing machine, etc.,” explains Stig Knudsen who continues: When you have someone with years of operational experience and that mindset working together/side by side with an engineer with a Ph.D it gets really nerdy - and very productive.”
Prototypes were subsequently set up in different places around Skanderborg Utility’s distribution network – either as part of planned renovations, or in areas with suspected leakages that the prototypes then helped find.
First and foremost, Skanderborg Utility ensured that the meter was tested with the correct noise sources, but another, equally valuable contribution was their knowledge of sound and noise in the network. This was a completely new area for Kamstrup: what sound does a hole make? ”We had to learn what a leak sounds like,” explains Stig Knudsen.
Listening meetings were set up for Kamstrup and Skanderborg Utility to discuss just that, as the sound of a drilled hole is very different from the sound of a breach or leak. ”Based on our experience, we knew that drilling a clean hole in a pipe wasn’t true to life – in reality a breach is usually a tear in the pipe, which creates a more whistling sound than a round hole does,” explains Frank Nielsen.
Skanderborg Utility therefore provided Kamstrup with real pieces of piping with leak holes to investigate and test in order to learn how the type of pipe, material, composition, pressure, etc. might affect the sound of a leak. This work was crucial to the development of the new meter, explains Stig Knudsen: ”The meter listens all day, but takes the lowest background noise so we have a baseline. But when we started out, we didn’t know what to look for. Today we know what a leak sounds like.”