Bayer Clinitek Status®

The Clinitek Status® automatically analyses urine strips, eliminating the errors that can arise from human visual judgements. It is particularly simple to use because of a touch-screen user interface and a motorised drawer that accepts the reagent strip or cassette and automatically positions it under the instrument's optical analysis sensors. Previous sample drawer systems worked perfectly under normal conditions with operators who knew the instrument, but prototype testing highlighted a possible problem with new users or staff with no training.

Unsure about manually pushing the drawer in, they could use too much force and damage the motor's gear teeth. Cambridge Consultants helped Bayer redesign the draw mechanism.

The motion control solution that Cambridge Consultants devised involved a heavier-duty motor and gearbox than had been used in previous systems. It was also specifically located to ensure that force on the drawer can never damage it. This was combined with electronic circuit advice to assist the Bayer team in the design of an improved control and drive strategy. This involved sensing the insertion of the drawer by feedback from the motor windings and driving the motor in a more sophisticated way, with a special motion profile that improves both the engagement process and the final positioning of the reagent under the optics.

The sample drawer itself and the mouth of the enclosure were also designed to make table insertion intuitive - with mechanical shaping and visual indication of the right orientation. These mechanical changes were achieved using modifications to existing moulding tools. This avoided the time and cost involved with producing completely new tools.

After 18 months of commercialisation, the Clinitek Status analyser has already become the new leader in its segment of the urinalysis market. With thousands of installations worldwide, undergoing high-frequency daily use in hospital wards and healthcare practices, there have been no failures attributable to design problems with the new moving-part mechanism.