Life-critical medical devices such as anesthesia gas monitors must make fast, accurate readings. But meeting these performance requirements becomes increasingly challenging for design engineers as they try to decrease the overall size of the device. To meet the need for oxygen sensors in shrinking device space, Hummingbird Sensing Technology has developed the Paracube Sprint, which the company says is the world's smallest fast-response paramagnetic oxygen sensor.

"The requirement that drove the development of the Paracube Sprint was anesthesia gas-monitoring systems--or rather, the physical space that these workstations take up," says Martin Cox, business unit manager, transducers, Hummingbird Sensing Technology. "A number of OEMs want to reduce the form factor of these devices across the board, and the reduction of an oxygen sensor is crucial to that."

Cox adds that the miniaturization of optical components, such as LEDs and photocells, was critical for achieving the Sprint's ultracompact 43.3 × 30 × 33.5-mm form factor. Smaller microprocessors enabled a reduction in the size of the Sprint's electronics, while advances in magnetic technology helped Hummingbird engineer the correct flux density for the cell. Finally, improvements in the metal injection molding process made it possible for the cell to be manufactured to such small dimensions.

"The challenge for Hummingbird was to deliver a sensor that offered all the benefits of a smaller form factor without compromising a single aspect of performance," Cox says.

Although based on Hummingbird's Paracube Micro platform, the Sprint is designed as a fast flow sensor, in contrast to the diffusion-based sensor of the Micro. This feature, Cox notes, better accommodates the breath-by-breath oxygen requirements of anesthesia, pulmonary function testing, and other life-critical healthcare systems. The Sprint also updates its readings every 10 milliseconds via digital signal output, enabling it to take 10 readings per second, while the analog output option enables a continuous signal. It also offers a full measurement range of 0 to 100% oxygen and features a nonconsumable design with good measurement stability, eliminating the need for daily calibration.

"While the Sprint can take up to 100 G of shock, the paramagnetic technology means it is best suited for stationary or transportable devices," Cox comments. "Manufacturing advances mean the cost of paramagnetic technology has greatly reduced [compared with] traditional catalytic cells to the point that paramagnetic is clearly a more cost-effective choice for users looking to get long-term cost-of-ownership from their equipment."

Hummingbird Sensing Technology, div. of Servomex
Crowborough, UK
www.hummingbirdsensing.com