US3609379A
Expired / Lapsed
US
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Photoelectric drop sensing and timing control for intravenous feed and other flow control applications
Assignee: General Electric Co
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Filing: 1969-05-13
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Granted: 1971-09-28
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Expires: 1989-05-13
Abstract
Abstract This disclosure is of a fluid flow rate control for intravenous feed and like applications wherein flow occurs in dropwise fashion. Drops are sensed photoelectrically by interruption of a light beam incident upon a photocell, the resulting fluctuations in output of the cell being detected and utilized for closed loop control of a flow adjustment device operative to correct any drop timing error detected. The control circuitry described includes means enabling discrimination between discrete drops and a steady stream or column of liquid as occasionally is experienced in intravenous feed apparatus, and means enabling discrimination also as between the primary or main drop and small secondary drops which sometimes form with and trail immediately after the main drop and which, if sensed, introduce errors into the drop timing measure obtained. For purposes of shutting off flow just prior to exhaustion of the fluid supply, means are provided for sensing fluid level at some point in the system indicative of the approach of this condition, such sensing being accomplished by photoelectric means arranged to afford reliable indication of fluid level irrespective of the transparency or opacity of the particular fluid involved. Means also are provided for shutting off flow in the event of photosensor light source failure.
Inventors
- 👤 Herbert John Hildebrandt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:13
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/16886; A61M5/1689; G; G05; G05D; G05D7/00; G05D7/06; G05D7/0617; Y; Y10; Y10S; Y10S128/00; Y10S128/13
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
335 words
For regulating fluid flow through a flow line having interposed therein a drop chamber in which flow occurs in the form of discrete drops including primary drops sometimes trailed by smaller secondary drops, apparatus comprising: drop detection means including a photoelectric sensor element and light source having orientation with respect to said drop chamber such that light from said source traverses the drop chamber and then is incident upon said sensor element except when intercepted by a drop falling through the chamber, said sensor element being responsive to fluctuations in incident light due to said drops to produce an electrical signal output in time synchronism with each thereof; pulse-generating means having coupled thereto the electrical signal output from said sensor element and being responsive to such sensor signals to generate output pulses synchronized therewith, said pulse-generating means including means responsive to the start of each output pulse to disable the generation of any succeeding pulse through a time period of duration greater than that characteristically separating each primary drop and its trailing secondary drops but substantially smaller than the time period characteristically separating successive primary drops at highest normal flow rate; fluid flow adjusting means; and control means responsive to said pulse generator output pulses for actuating said fluid flow adjusting means so as to maintain a predetermined primary drop timing for fluid flow rate control. 2. Fluid flow regulating apparatus as defined in claim 1 wherein said fluid flow adjusting means includes motor means adapted to be driven in both continuous and stepwise modes for accomplishing adjustment of fluid flow rate, and wherein said conTrol means for said motor means includes discriminator means responsive to said pulse generator output pulses to drive said motor means in said stepwise mode for pulse repetition rates corresponding to fluid flow rates below the highest normal flow rate and to drive said motor means in said continuous mode for higher pulse repetition rates, whereby flow adjustment is more quickly accomplished when flow rates exceed the highest normal rate.
Claim 2
Dependent Claim
118 words
Fluid flow regulating apparatus as defined in claim 1 wherein said apparatus further includes means responsive to operational irregularity to generate an irregularity signal separated in frequency from the frequency of said drop pulses at normal fluid flow rates, wherein said fluid flow adjusting means is operable in a first mode to maintain a predetermined fluid flow rate and operable in a second mode to close off fluid flow, and wherein said control means includes discriminator means having said drop and irregularity signals applied thereto and being responsive to said drop signal to actuate said flow adjusting means in said first mode and responsive to said irregularity signal to actuate said flow adjusting means in said second mode.
Claim 3
Dependent Claim
104 words
Fluid flow regulating apparatus as defined in claim 3 wherein said fluid flow adjusting means includes motor means adapted to be driven in stepwise and continuous modes for accomplishing flow rate adjustment in said first and second modes, respectively, and wherein said discriminator means drives said motor means in said stepwise mode in response to drop signals having pulse repetition rates corresponding to fluid flow rates below the highest normal flow rate, and drives said motor means in said continuous mode in response to said irregularity signal and to drop signals having pulse repetition rates exceeding that corresponding to the highest normal flow rate.
Claim 4
Dependent Claim
76 words
Fluid flow regulating apparatus as defined in claim 3 wherein said irregularity signal is a pulsed signal of pulse repetition rate substantially higher than the drop signal pulse repetition rate corresponding to highest normal fluid flow rate, and wherein said discriminator means responds to both said irregularity signal and to said drop signal when of pulse repetition rate exceeding that corresponding to highest normal flow rate to actuate said flow adjusting means in said second mode.
Claim 5
Dependent Claim
57 words
Fluid flow regulating apparatus as defined in claim 3 wherein said irregularity signal is a DC signal and wherein said discriminator means responds to both said DC irregularity signal and to said drop signal when of pulse repetition rate exceeding that corresponding to highest normal fluid flow rate to actuate said flow-adjusting means in said second mode.
Claim 6
Dependent Claim
78 words
Fluid flow regulating apparatus as defined in claim 3 wherein the operational irregularity of which said irregularity signal is indicative is a continuing change in level of illumination of said sensor element such as occasioned by the fall of a steady stream of liquid through the drop chamber, and wherein said irregularity signal generating means further includes means for limiting the maximum duration of said irregularity signal when generated in response to such continuing change in sensor illumination.
Claim 7
Dependent Claim
46 words
Fluid flow regulating apparatus as defined in claim 3 wherein the operational irregularity of which said irregularity signal is indicative is failure of said light source, and wherein such failure is detected by sensing its affect on the electrical signal output of said photoelectric sensor element.
Claim 8
Dependent Claim
110 words
Fluid flow regulating apparatus as defined in claim 3 wherein normal operation said drop chamber maintains a pool of liquid therein and wherein the operational irregularity sensed is a fall in level of such pool, and further including: a second photoelectric sensor element and light source having orientation with respect to said drop chamber such that light from said source traverses the drop chamber below the normal level of said pool and in the absence thereof then is incideNt upon said sensor element; and means operative under control of said second photoelectric sensor for generating said irregularity signal upon illumination of said sensor element due to absence of said pool.
Claim 9
Dependent Claim
99 words
Fluid flow regulating apparatus as defined in claim 9 wherein said drop chamber comprises a tubular member having a vertical axis and a closed lower end in which is maintained said liquid pool, and wherein the line of sight between said second photoelectric sensor element and its light source as substantially displaced from said drop chamber vertical axis, whereby light from said source will illuminate said sensor element in the absence of said pool but in the presence thereof will not illuminate the sensor element because defected by refraction and attenuated by absorption in the liquid of the pool.
Claim 10
Dependent Claim
229 words
For regulating fluid flow through a flow line having interposed therein a drop chamber in which flow occurs in the form of discrete drops including primary drops sometimes trailed by smaller secondary drops, apparatus comprising: drop detection means including a photoelectric sensor element and light source having orientation with respect to said drop chamber such that light from said source traverses the drop chamber and then is incident upon said sensor element except when intercepted by a drop falling through the chamber, said sensor element being responsive to fluctuations in incident light due to said drops to produce an electrical signal output in time synchronism with each thereof; pulse-generating means having coupled thereto the electrical signal output from said sensor element and being responsive thereto to produce a series of output pulses each having its leading edge in time coincidence with a primary drop and being of time duration greater than the time spacing characteristically separating each primary drop and any associated secondary drops but substantially smaller than the time period characteristically separating successive primary drops at highest normal flow rate; fluid flow adjusting means; and control means responsive to leading edge timing of said pulse generator output pulses and independent of the time duration of said pulses for actuating said fluid flow adjusting means so as to maintain a predetermined primary drop timing for fluid flow rate control.
Claim 11
Dependent Claim
229 words
For regulating fluid flow through a flow line having interposed therein a drop chamber in which flow occurs in the form of discrete drops including primary drops sometimes trailed by smaller secondary drops, apparatus comprising: drop detection means including a photoelectric sensor element and light source having orientation with respect to said drop chamber such that light from said source traverses the drop chamber and then is incident upon said sensor element except when intercepted by a drop falling through the chamber, said sensor element being responsive to fluctuations in incident light due to said drops to produce an electrical signal output in time synchronism with each thereof; pulse-generating means having coupled thereto the electrical signal output from said sensor element and being responsive thereto to produce a series of output pulses each having its leading edge in time coincidence with a primary drop and being of time duration greater than the time spacing characteristically separating each primary drop and any associated secondary drops but substantially smaller than the time period characteristically separating successive primary drops at highest normal flow rate; fluid flow adjusting means; and control means responsive to leading edge timing of said pulse generator output pulses and independent of the time duration of said pulses for actuating said fluid flow adjusting means so as to maintain a predetermined primary drop timing for fluid flow rate control.
Claim 12
Dependent Claim
112 words
Fluid flow regulating apparatus as defined in claim 11 wherein said drop signal constitutes a first control signal, wherein there is included means for generating a second control signal separated in frequency from said first signal and indicating an operating condition accommodation to which entails actuation of said fluid flow adjusting means in flow decreasing direction, and wherein said control means further includes discriminator means having applied thereto said first and second signals and being responsive to said first signal to actuate said flow-adjusting means in whichever direction necessary to maintain desired fluid flow rate and responsive to said second signal to actuate said flow-adjusting means to drive only in flow-decreasing direction.
Claim 13
Dependent Claim
206 words
For regulating fluid flow through a flow line having interposed therein a drop chamber in which flow occurs in the form of discrete drops, apparatus comprising: a drop detector responsive to said drops to produce an output signal comprising pulses each beginning in time synchronism with a drop; fluid flow adjusting means including motor means adapted to be driven in both continuous and stepwise modes for accomplishing adjustment of fluid flow rate through said flow line; first and second control signal generating means having as an input the drop pulse output of said drop detector and being responsive thereto to generate a first control signal for drop pulse repetition rates corresponding to fluid flow rates below the highest normal rate and to generate a second control signal for drop pulse repetition rates above said highest normal rate; and control means for said motor Means having said first and second control signals applied thereto and being responsive to said first control signal to drive said motor means in said stepwise mode except on occurrence of said second control signal and being responsive thereto to drive said motor means in said continuous mode, whereby flow adjustment is more quickly accomplished when flow rates exceed the highest normal rate.
Claim 14
Dependent Claim
206 words
For regulating fluid flow through a flow line having interposed therein a drop chamber in which flow occurs in the form of discrete drops, apparatus comprising: a drop detector responsive to said drops to produce an output signal comprising pulses each beginning in time synchronism with a drop; fluid flow adjusting means including motor means adapted to be driven in both continuous and stepwise modes for accomplishing adjustment of fluid flow rate through said flow line; first and second control signal generating means having as an input the drop pulse output of said drop detector and being responsive thereto to generate a first control signal for drop pulse repetition rates corresponding to fluid flow rates below the highest normal rate and to generate a second control signal for drop pulse repetition rates above said highest normal rate; and control means for said motor Means having said first and second control signals applied thereto and being responsive to said first control signal to drive said motor means in said stepwise mode except on occurrence of said second control signal and being responsive thereto to drive said motor means in said continuous mode, whereby flow adjustment is more quickly accomplished when flow rates exceed the highest normal rate.
Claim 15
Dependent Claim
62 words
Fluid flow regulating apparatus as defined in claim 13 further including means responsive to operational irregularity to transmit to said control means an irregularity signal separated in frequency from said drop signal at normal fluid flow rates, and wherein said control means is responsive to said irregularity signal to drive said motor means in said continuous mode upon occurrence of such signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |