Patent EP0077413A1 successfully refreshed from Google Patents.
EP0077413A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for electrically measuring fluid flow rates
Assignee: Memorial Sloan Kettering Cancer Center
•
Filing: 1981-10-20
•
Granted: —
•
Expires: 2001-10-20
Abstract
Abstract A system for measuring the flow rate of electrolytic fluids includes a flow cell (10) with a cylindrical channel for the fluid flow and a pair of spaced apart electrodes conformed to the cylindrical surface of the flow channel. The electrodes are electrically conductive and inert to the fluid and are in contact with the fluid flow for a desired range of flow measurement. A monopolar pulse train is applied across the electrodes to effect a cell impedance which is inversely proportional to the rate of flow. A control signal is produced in response to the potential across the electrodes and this signal is applied to the pulse train generator varying the pulse train current to effect an increase in the current in response to an increase in flow rate whereby the cell impedance is stabilized for every flow rate and the electrode potential is representative of the flow rate.
Inventors
- 👤 David Rottenberg
- 👤 Saul Miodownik
- 👤 W.E. Epifanio Ii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 09:05
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/56; A; A61; A61B; A61B5/00; A61B5/42; A61B5/4261; A61B5/4266
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
228 words
A device for measuring the flow rate of electrolytic fluids, comprising: a flow cell including means forming a cylindrical flow channel receptive of the fluid flow to be measured and a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and to be flush therewith, the electrodes comprising electrically conductive material inert to the fluid of the flow to be measured, wherein the channel is configured to effect contact of the electrodes with the fluid flow for a desired range of flow rate measurement; means for applying a monopolar pulse train across the flow cell electrodes having a selected amplitude, period and pulse width to effect a cell impedance across the electrodes which is inversely proportional to the the rate of flow, the pulse applying means including means for varying the current applied across the electrodes in a given unit of time in response to a control signal applied thereto; and means for producing the control signal in response to the potential across the electrodes in the given unit of time and for applying the control signal to the means for varying the pulse train current to effect an increase in current in response to an increase in the flow rate, whereby the cell impedance is stabilized for every flow rate and the electrode potential is representative of the flow rate.
Claim 2
Independent Claim
228 words
A device for measuring the flow rate of electrolytic fluids, comprising: a flow cell including means forming a cylindrical flow channel receptive of the fluid flow to be measured and a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and to be flush therewith, the electrodes comprising electrically conductive material inert to the fluid of the flow to be measured, wherein the channel is configured to effect contact of the electrodes with the fluid flow for a desired range of flow rate measurement; means for applying a monopolar pulse train across the flow cell electrodes having a selected amplitude, period and pulse width to effect a cell impedance across the electrodes which is inversely proportional to the the rate of flow, the pulse applying means including means for varying the current applied across the electrodes in a given unit of time in response to a control signal applied thereto; and means for producing the control signal in response to the potential across the electrodes in the given unit of time and for applying the control signal to the means for varying the pulse train current to effect an increase in current in response to an increase in the flow rate, whereby the cell impedance is stabilized for every flow rate and the electrode potential is representative of the flow rate.
Claim 3
Dependent Claim
83 words
The device according to claim 1, for the measurement of cerebrospinal fluid shunt flow, wherein the means forming cylindrical flow channel includes inlet means outlet means for connecting same in series with a cerebrospinal fluid shunt tube, a cylindrical outer surface configured to be substantially equal in diameter to that of the shunt tube and the inner diameter of the fluid channel is substantially equal in diameter to that of the shunt tube, whereby the flow cell is surgically implantable with the shunt.
Claim 4
Dependent Claim
34 words
The device according to claim 1 or 2, wherein pulse train applying means comprises a variable pulse generator and the means for producing the control signal comprises an integrator and a variable gain amplifier.
Claim 5
Independent Claim
182 words
A method of measuring the flow rate of electrolytic fluids, comprising the steps of: a. a connecting flow cell having a cylindrical flow channel in series with the fluid flow; b. providing a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and flush therewith and comprising an electrically L conductive material inert to the fluid of the flow to be measured to effect contact of the electrodes with the fluid flow for a desired range of flow rate measurement; c. applying a monopolar pulse train across the flow cell electrodes having a selected amplitude, period and pulse width to effect a cell impedance across the electrodes which is inversely'proportional to the rate of flow; d. producing a control signal in response to the potential across the electrodes in a given unit of time; e. varying the pulse train current to effect an increase in current in response to an increase in the flow rate whereby the cell impedance is stabilized for every flow rate and the electrode potential is representative of the flow rate.
Claim 6
Independent Claim
182 words
A method of measuring the flow rate of electrolytic fluids, comprising the steps of: a. a connecting flow cell having a cylindrical flow channel in series with the fluid flow; b. providing a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and flush therewith and comprising an electrically L conductive material inert to the fluid of the flow to be measured to effect contact of the electrodes with the fluid flow for a desired range of flow rate measurement; c. applying a monopolar pulse train across the flow cell electrodes having a selected amplitude, period and pulse width to effect a cell impedance across the electrodes which is inversely'proportional to the rate of flow; d. producing a control signal in response to the potential across the electrodes in a given unit of time; e. varying the pulse train current to effect an increase in current in response to an increase in the flow rate whereby the cell impedance is stabilized for every flow rate and the electrode potential is representative of the flow rate.
Claim 7
Dependent Claim
80 words
The method according to claim 4, for the measurement of cerebrospinal fluid shunt flow, comprising connecting shunt tubing to a patient to establish-a cerebrospinal fluid shunt, forming the flow channel with a cylindrical outer surface configured to be substantially equal in diameter to that of the shunt tubing and with the inner diameter of the fluid channel substantially equal in diameter to the inner diameter of the shunt tubing, and connecting the flow cell in series with the shunt tubing.
Claim 8
Dependent Claim
19 words
The method according to claim 5, further comprising implanting the flow cell in the patient with the shunt tubing.
Claim 9
Dependent Claim
71 words
A surgically implantable flow cell for . effecting the measurement of cerebrospinal fluid shunt flow, the cell comprising: means forming cylindrical flow channel having inlet means outlet means for connecting same in series with an cerebrospinal fluid shunt; and a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and flush therewith, the electrodes comprising electrically conductive material which is inert to cerebrospinal fluid.
Claim 10
Dependent Claim
71 words
A surgically implantable flow cell for . effecting the measurement of cerebrospinal fluid shunt flow, the cell comprising: means forming cylindrical flow channel having inlet means outlet means for connecting same in series with an cerebrospinal fluid shunt; and a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and flush therewith, the electrodes comprising electrically conductive material which is inert to cerebrospinal fluid.
Claim 11
Dependent Claim
55 words
The cell according to claim 7, wherein for a given shunt tube, the means forming the flow channel has a cylindrical outer surface configured to be substantially equal in diameter to that of the shunt tube and the inner diameter of the fluid channel is substantially equal in diameter to that of the shunt tube.
Claim 12
Dependent Claim
141 words
Apparatus for measuring flow rates in.a fluid which conducts current comprising: an electrolytic flow cell having said fluid to be measured passing therethrough, said flow cell having a pair of spaced electrodes in contact with said fluid passing through said flow cell, pulse generator means for controllably providing monopolar pulses having a selectable amount of current per unit time, means for coupling said monopolar pulses to said electrodes of said flow cell, means for deriving a direct current output from said cell proportional to the current flow through said electrodes, feedback means for coupling said direct current output to said pulse generator means for controlling the current of said monopolar pulses per unit time to thereby stabilize the direct current output from said electrodes to produce a different value for each flow rate whereby a flow rate measurement can be made.
Claim 13
Dependent Claim
141 words
Apparatus for measuring flow rates in.a fluid which conducts current comprising: an electrolytic flow cell having said fluid to be measured passing therethrough, said flow cell having a pair of spaced electrodes in contact with said fluid passing through said flow cell, pulse generator means for controllably providing monopolar pulses having a selectable amount of current per unit time, means for coupling said monopolar pulses to said electrodes of said flow cell, means for deriving a direct current output from said cell proportional to the current flow through said electrodes, feedback means for coupling said direct current output to said pulse generator means for controlling the current of said monopolar pulses per unit time to thereby stabilize the direct current output from said electrodes to produce a different value for each flow rate whereby a flow rate measurement can be made.
Claim 14
Dependent Claim
25 words
The apparatus set forth in claim 9, in which said flow cell comprises an enclosed body having a channel therethrough through which said fluid passes.
Claim 15
Dependent Claim
25 words
The apparatus set forth in claim 10, in which said electrodes are shaped to conform to the shape of said channel and are recessed therein.
Claim 16
Dependent Claim
27 words
The apparatus set forth in claim 10, in which said pulse generator means has a variable frequency and duty cycle which is controlled by said feedback means.
Claim 17
Independent Claim
78 words
A method of measuring slow flow rates of an electrolytic fluid moving past a pair of spaced electrodes comprising the steps of: applying a monopolar pulse train across said electrodes having a selected amount of current per unit time, detecting and amplifying the output from said spaced electrodes, and feeding back the amplified output from said,spaced electrodes for controlling the current per unit time of said pulse train across said electrodes for stabilizing the output from said electrodes.
Claim 18
Independent Claim
78 words
A method of measuring slow flow rates of an electrolytic fluid moving past a pair of spaced electrodes comprising the steps of: applying a monopolar pulse train across said electrodes having a selected amount of current per unit time, detecting and amplifying the output from said spaced electrodes, and feeding back the amplified output from said,spaced electrodes for controlling the current per unit time of said pulse train across said electrodes for stabilizing the output from said electrodes.
Claim 19
Dependent Claim
43 words
The method set forth in claim 13, including the steps of: incorporating the electrodes in an enclosed flow cell with an opening therethrough, and implanting said flow cell in the body of a patient for determining the flow rate of a body fluid..
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.