Air bubble detector
First Claim
1. An air detector for use in conjunction with a generally transparent intravenous fluid conduit, the inner wall of said conduit being reflective to light, comprising:
- (a) a light source positioned alongside said conduit;
(b) first light-detecting means positioned alongside said conduit at a location diametrically opposite and facing said light source, and adapted for receiving direct light passing through the fluid in said conduit;
(c) second light-detecting means positioned alongside said conduit between said light source and said first light-detecting means, and adapted for receiving reflections from said inner wall of the conduit; and
(d) logic means coupled to said first and second light-detecting means and arranged to produce a particular signal when, and only when, the light levels detected separately and simultaneously by said first and second light-detecting means bear a predetermined logical relationship to one another.
0 Assignments
0 Petitions
Accused Products
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.
91 Citations
10 Claims
-
1. An air detector for use in conjunction with a generally transparent intravenous fluid conduit, the inner wall of said conduit being reflective to light, comprising:
-
(a) a light source positioned alongside said conduit; (b) first light-detecting means positioned alongside said conduit at a location diametrically opposite and facing said light source, and adapted for receiving direct light passing through the fluid in said conduit; (c) second light-detecting means positioned alongside said conduit between said light source and said first light-detecting means, and adapted for receiving reflections from said inner wall of the conduit; and (d) logic means coupled to said first and second light-detecting means and arranged to produce a particular signal when, and only when, the light levels detected separately and simultaneously by said first and second light-detecting means bear a predetermined logical relationship to one another. - View Dependent Claims (2, 5, 6)
-
-
3. In association with a generally cylindrical transparent intravenous fluid conduit, the inner wall of said conduit being reflective to light, an air detector comprising:
-
(a) a pair of detector units spaced from one another in the direction of the axis of said conduit, each said detector unit including (i) a light course positioned alongside said conduit (ii) first light-detecting means positioned alongside said conduit at a location generally diametrically opposite and facing said light source and adapted for receiving direct light passing through said conduit; and (iii) second light-detecting means positioned alongside said conduit between said light source and said first light-detecting means and adapted for receiving reflections from said inner wall of said conduit; and (b) logic means coupled to said first and second light-detecting means of each of said detector units and arranged to produce a particular signal when, and only when, in each of said detector units, the light levels detected separately and simultaneously by said first and second light-detecting means bear a predetermined logical relationship to one another. - View Dependent Claims (7, 8)
-
-
4. An air detector for use in conjunction with a generally transparent fluid conduit, the inner wall of said conduit being reflective to light, comprising:
-
(a) a light source; (b) first light-detecting means so positioned as to detect light traveling from said light source along a first path traversing said fluid; (c) second light-detecting means so positioned as to detect light traveling from said light source along a second path involving a reflection from the inner wall of said conduit but not traversing said fluid; and (d) signal-producing means associated with said first and second light-detecting means and arranged to produce a particular signal when and only when, the levels of light detected separately and simultaneously by said first and second light-detecting means bear a predetermined logical relationship to one another.
-
-
9. A method of detecting air in a transparent fluid conduit, the inner wall of the conduit being reflective to light comprising the steps of:
-
(a) transmitting light along a first path traversing said fluid, and along a second path involving a reflection from the inner wall of said conduit but not traversing said fluid; (b) separately and simultaneously detecting the relative levels of light transmitted through said paths; and (c) producing a particular signal representative of whether said light levels are substantially the same or substantially different. - View Dependent Claims (10)
-
Specification