Originally Published EMDM
March/April 2003
TECHNOLOGY NEWS
Electronic ComponentsMEMS-Based Sensors Measure Liquid Flow Down to 0.03 µl/min
Liquid-flow sensors currently under development for integration with drug-delivery, glucose-monitoring, dialysis, and infusion devices use microelectromechanical systems (MEMS) technology to measure and control minute quantities of fluids. Evaluation prototypes for medical applications have been available since the beginning of this year, according to John Smith-Malzfeldt, business development manager, Commerical Switches and Sensors, Honeywell Sensing and Control (Offenbach, Germany). The official product launch is scheduled for the third quarter of 2003.
Two styles of the sensor, which uses a thermal-based technology to measure flow rates down to 0.03 µl/min, will be introduced: an isolated model fitted with a tube to separate the fluid from the sensor and a nonisolated version in which the fluid comes into direct contact with the sensor. Both models are small in size; do not retain contaminants, condensates, or liquids; and are suitable for use in disposable products. By employing a mechanical bypass design, the sensor can also measure liquid flows exceeding 1L/min.
Smith-Malzfeldt cites a company in northern Germany using MEMS-based products to deliver asthma medication as an example of the promise that this technology holds. “This MEMS device produces particles that are less than 5 µm in diameter,” sufficiently small in size for the medication to reach the very bottom of the lungs. “The firm has all the necessary EU approvals and has a huge production facility that is ready to roll,” adds Smith-Malzfeldt.
Although Honeywell is by no means a newcomer to the medical arena, “our company’s CEO has identified biomedical and medical as high-growth markets for us,” says Smith-Malzfeldt. (It is worth noting that Honeywell recently acquired Invensys Sensor Systems, which has 13 production facilities in six countries.) “I wouldn’t call this a redirection, but it does mean that Honeywell is now prepared to invest more resources in the medical market, and it may build dedicated production facilities or establish targeted partnerships.” The liquid-flow sensors are but one manifestation of this emphasis.
Other ongoing research projects at Honeywell Sensing and Control involve the development of implantable metering pumps and microvalves that operate electrostatically. In essence, says Smith-Malzfeldt, “we will be able to measure flow, actuate it by means of a pump, and control it via valves.”
Norbert Sparrow
Copyright ©2003 European Medical Device Manufacturer
