Air bubble detector
US4366384A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 18, 1980 |
| Grant date | Dec 28, 1982 |
| Priority date | — |
| Expiry date | Jun 18, 2000 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61M5/365
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Air bubbles in a transparent intravenous solution conduit are detected, regardless of whether the solution is opaque or clear, by directing a light source at the conduit and detecting light shining through the solution with a first light sensor while detecting light reflected from the interior wall of the conduit with a second light sensor. If liquid is present in the conduit, whether clear or opaque, one sensor will see a low light level while the other sees a high level. If air is present, both sensors see a high light level. By EXCLUSIVE-OR'ing the outputs of the two sensors, a logic signal is obtained which is high only when the presence of liquid in the conduit is being detected. Means using two sensor assemblies spaced axially along the conduit, and a counter associated with each, are also provided to allow passage of minor air bubbles, and to provide a backup signal representative of a predetermined volume of air passing either assembly independently of the other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.