Student retrieves fifty year old sensor from skip

A fifty year old Kistler sensor retrieved from a rubbish skip and left forgotten, proved to be still working well, and easy to recalibrate: the lucky student gets a modern miniature sensor replacement

Many years ago, student Tim Hands spotted the glint of stainless steel in a rubbish skip, outside the Cambridge University Engineering Department: it turned out to be an old pressure sensor.

Thinking that it might be useful, he put the sensor into a drawer.

Years later, working for engine emission control specialists, Cambustion, an independent company that has close links with Cambridge University Engineering Department, Tim needed a sensor for a project and remembered the one he had found in the skip.

The only identification on the sensor was "SLM 425 Swiss" so Cambustion asked Swiss sensor manufacturer Kistler Instruments if they could supply a cable to fit.

Kistler recognised the sensor as one they had sold in 1954 and, whilst they could supply a suitable cable, the opportunity to retest an authentic 50 year old SLM sensor was too good to miss.

Cambustion was happy to accept the offer of one of Kistler's latest miniature M5 pressure sensors in exchange for the 50 year old SLM.

On its return to Switzerland, the sensor was put through its paces in the Kistler calibration laboratory where it was found to be in good working order.

Isolation was well within the original specification and re-calibration proved to be as simple today as it was in 1954.

Although no one would expect a sensor to be guaranteed for fifty years, this does show that Kistler sensors should not be consigned to the rubbish bin too early!.

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