Method for correcting the drift offset of a transducer
US5450336A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1993 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Jan 29, 2013 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61M2205/8212
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method for correcting the drift offset of a transducer is disclosed which method is used in connection with a portable, battery-powered, hand-held system for releasing a controlled dose of aerosol medication for inhalation by a patient. The device includes a durable body and a medication cassette inserted in the durable body. The body includes a flow sensor having an asymmetrical orifice that is calibrated, independent of the cassette, to convert the sensed pressure due to flow into a flow rate. The orifice is separately calibrated for an inhalation flow rate range and an exhalation flow rate range over a selected number of known flow rates. The sensed pressure value is corrected for transducer offset drift and converted to a flow rate using the calibration data and piecewise linear interpolation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.