US3871229A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drop sensing apparatus
Assignee: Data Service of America Inc
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Filing: 1974-01-02
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Granted: 1975-03-18
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Expires: 1994-01-02
Abstract
Abstract Control apparatus for a drop-feed intravenous system includes an enclosure having a thermally responsive probe sensor on which a succesion of liquid drops impinge. The sensor is insulated electrically from the drop stream but is thermally coupled to the stream to generate pulses at a rate corresponding to the periodicity of the falling drops. These pulses are compared with an adjustable reference pulse rate and any differential detected is used to regulate the liquid flow and thus to adjust the drop rate to the reference rate. Aural and visual alarm systems respond to out-of-limit conditions detected by the monitoring system.
Inventors
- 👤 John H Fletcher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:33
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/16886; A61M5/1689
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
173 words
Apparatus for sensing the passage of liquid drops successively falling along a predetermined vertical path, said apparatus comprising: A. an enclosure including means for establishing a vertical drop path; and B. a probe mounted within the enclosure and having a portion positioned directly in the drop path, said probe comprising 1. an electrically conductive element located in that portion of the probe which is positioned in the drop path, the conductivity of the element being significantly variable with its temperature, 2. a pair of leads connected with the conductive element and having terminals outside the enclosure for conducting current to and from the conductive element, and 3. insulating material enclosing both the conductive element and the portion of the leads within the said enclosure and electrically isolating them from falling drops, such material being, however, of such thinness in the vicinity of the conductive element as not significantly to isolate the element from thermal gradients created by drops falling successively on that portion of the probe which is positioned in the drop path.
Claim 2
Dependent Claim
173 words
Apparatus for sensing the passage of liquid drops successively falling along a predetermined vertical path, said apparatus comprising: A. an enclosure including means for establishing a vertical drop path; and B. a probe mounted within the enclosure and having a portion positioned directly in the drop path, said probe comprising 1. an electrically conductive element located in that portion of the probe which is positioned in the drop path, the conductivity of the element being significantly variable with its temperature, 2. a pair of leads connected with the conductive element and having terminals outside the enclosure for conducting current to and from the conductive element, and 3. insulating material enclosing both the conductive element and the portion of the leads within the said enclosure and electrically isolating them from falling drops, such material being, however, of such thinness in the vicinity of the conductive element as not significantly to isolate the element from thermal gradients created by drops falling successively on that portion of the probe which is positioned in the drop path.
Claim 3
Dependent Claim
34 words
Apparatus according to claim 1 in which the transverse dimension of that portion of the probe positioned directly in the drop path is comparable with or less than the diameter of the falling drops.
Claim 4
Dependent Claim
25 words
a pair of leads connected with the conductive element and having terminals outside the enclosure for conducting current to and from the conductive element, and
Claim 5
Dependent Claim
25 words
a pair of leads connected with the conductive element and having terminals outside the enclosure for conducting current to and from the conductive element, and
Claim 6
Dependent Claim
16 words
an extended major axis substantially coincident with the central axis of the predetermined drop path, and
Claim 7
Dependent Claim
16 words
an extended major axis substantially coincident with the central axis of the predetermined drop path, and
Claim 8
Dependent Claim
14 words
an upwardly projecting end which lies directly in the drop path; said probe comprising:
Claim 9
Dependent Claim
14 words
an upwardly projecting end which lies directly in the drop path; said probe comprising:
Claim 10
Dependent Claim
13 words
Apparatus according to claim 1 in which the conductive element is a thermistor.
Claim 11
Dependent Claim
66 words
insulating material enclosing both the conductive element and the portion of the leads within the said enclosure and electrically isolating them from falling drops, such material being, however, of such thinness in the vicinity of the conductive element as not significantly to isolate the element from thermal gradients created by drops falling successively on that portion of the probe which is positioned in the drop path.
Claim 12
Dependent Claim
66 words
insulating material enclosing both the conductive element and the portion of the leads within the said enclosure and electrically isolating them from falling drops, such material being, however, of such thinness in the vicinity of the conductive element as not significantly to isolate the element from thermal gradients created by drops falling successively on that portion of the probe which is positioned in the drop path.
Claim 13
Dependent Claim
45 words
Apparatus according to claim 1 in which means are connected to the terminals of the leads for supplying heating current to the conductive element during its use for drop-sensing purposes to maintain it at an average temperature above the predictable temperature of the falling drops.
Claim 14
Dependent Claim
23 words
an electrically conductive element within the upwardly projecting end of the probe; the conductivity of said element being significantly variable with its temperature,
Claim 15
Dependent Claim
23 words
an electrically conductive element within the upwardly projecting end of the probe; the conductivity of said element being significantly variable with its temperature,
Claim 16
Dependent Claim
24 words
a pair of leads connecting with the conductive element and having terminals outside the enclosure for conducting current to and from the conductive element,
Claim 17
Dependent Claim
24 words
a pair of leads connecting with the conductive element and having terminals outside the enclosure for conducting current to and from the conductive element,
Claim 18
Dependent Claim
40 words
Apparatus for sensing the passage of liquid drops successively falling along a predetermined vertical path, said apparatus comprising: A. an enclosure including means for establishing a vertical drop path; and B. an elongated probe mounted within the enclosure which has
Claim 19
Dependent Claim
40 words
Apparatus for sensing the passage of liquid drops successively falling along a predetermined vertical path, said apparatus comprising: A. an enclosure including means for establishing a vertical drop path; and B. an elongated probe mounted within the enclosure which has
Claim 20
Dependent Claim
13 words
Apparatus according to claim 5 in which the conductive element is a thermistor.
Claim 21
Dependent Claim
84 words
insulating material enclosing both the conductive element and the portion of the leads within the said enclosure and electrically isolating them from falling drops, such material being, however, of such thinness in the vicinity of the conductive element as not significantly to isolate the element from thermal gradients created by drops falling successively on the upwardly directed end of the probe, whereby periodic variations in the conductivity of the element produced by successively falling drops may be detected at the terminals of the leads.
Claim 22
Dependent Claim
84 words
insulating material enclosing both the conductive element and the portion of the leads within the said enclosure and electrically isolating them from falling drops, such material being, however, of such thinness in the vicinity of the conductive element as not significantly to isolate the element from thermal gradients created by drops falling successively on the upwardly directed end of the probe, whereby periodic variations in the conductivity of the element produced by successively falling drops may be detected at the terminals of the leads.
References Cited (Backward Citations)
US3390577A
Cited
US3655095A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |