Blood flow detection device

• US 4,881,413 A
• Filed: 10/31/1988
• Issued: 11/21/1989
• Est. Priority Date: 10/31/1988
• Status: Expired due to Term

• Current Assignee: Medtronic Bio-Medicus, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Bio-Medicus, Inc. (Medtronic Plc)
• Inventors: Basile, Andrew X., Graupmann, Lloyd E., Georgi, Donald K.
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): Chen, Hollis T.
• Application Number:
  US07/265,410
• Time in Patent Office: 386 Days
• Field of Search: 73/861.13, 73/861.12, 364/413.07, 128/DIG. 13, 128/691
• US Class Current: 73/861.12
• CPC Class Codes: A61B 5/0265 using electromagnetic means, e.g. electromagnetic flowmeter
• CPC Class Codes: A61M 1/3663 Flow rate transducers; Flow integrators
• CPC Class Codes: G01F 1/58 by electromagnetic flowmeters
• CPC Class Codes: G01F 1/588 combined constructions of electrodes, coils or magnetic circuits, accessories therefor
• CPC Class Codes: G01F 1/60 Circuits therefor
• CPC Class Codes: G01F 15/18 Supports or connecting means for meters
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

A blood flow monitoring system employing a disposable sensor for directing a flow of blood through an electromagnetic field to generate a voltage proportional to the flow of blood through the electromagnetic field. The flow detection system employs a disposable sensor having a lumen with a constricted cross-sectional area adapted to interact with an electromagnetic field to detect blood flow and in an enhanced variation includes an electromagnetic field focusing device for enhancing the electromagnetic field to focus the electromagnetic field across the path of blood flow through the constricted section of the lumen to intensify the voltage generated by the blood flow through the intensified electromagnetic field.

Claims

1. A blood flow meter system comprising:

a. a transducer means;

b. a tray means;

c. first electrical terminal means mounted in said tray means;

d. magnetic field generating means mounted in said transducer means for generating a magnetic field;

e. said magnetic field generating means including an electromagnet means mounted in said transducer means with poles of said electromagnetic means terminating at opposite sides of an opening in said transducer means;

f. said tray means adapted to move into engagement with said transducer means in said opening to position said first electrical terminals means generally between the poles of said electromagnetic means;

g. means for activating said generating means to generate a magnetic field between the poles of said electromagnetic means;

h. a disposable sensor means constructed of nonmagnetic and non-conductive material having a constricted section of lumen adapted to accommodate blood flow;

i. second electrical terminal means mounted in said sensor means perpendicular to the flow of blood through said sensor means and in communication with said constricted section of lumen;

j. said sensor means positioned in said tray means with said second terminal means in electrical contact with said first electrical means;

k. a first electromagnetic field focus means positioned within the electromagnetic field between the poles of said electromagnetic means and in alignment with the constricted section of lumen of said sensor means to focus said electromagnetic field perpendicular to said blood flow in said constricted section of lumen of said sensor means to amplify the electromagnetic field intensity; and

l. detection means connected to said second terminals for detecting the voltage induced by said flow of blood through said electromagnetic field.

2. A system in accordance with claim 1 which further includes a second electromagnetic field focus means positioned within the electromagnetic field between the poles of said electromagnetic means and positioned to cooperate with said first electromagnetic field focus means to focus said electromagnetic field.

3. A system in accordance with claim 1 in which said first electromagnetic focus means is mounted on said tray means.

5. A system in accordance with claim 1 in which said sensor means has a cavity and in which said first electromagnetic field focus means is positioned in said cavity.

6. A system in accordance with claim 2 in which said first electromagnetic field focus means is mounted in said transducer and in which said second electromagnetic field focus means is mounted in said sensor means.

7. A system in accordance with claim 2 in which said first electromagnetic field focus means is mounted in said transducer and in which said second electromagnetic field focus means is mounted in said tray means.

8. A system in accordance with claim 2 in which said sensor means has a cavity and in which said first electromagnetic focus means is positioned in said cavity and in which said second electromagnetic focus means is positioned in said tray means.

9. A system in accordance with claim 2 in which said sensor means has first and second cavities in alignment with said magnetic field and in which said first and second electromagnetic focus means and positioned in said first and second cavities.

10. A system in accordance with claim 1 in which said constricted cross-sectional area has a cross-sectional length greater than the cross-sectional width and in which said second electrical terminal means are mounted at the extremity of said length of said cross-sectional area

11. A system in accordance with claim 10 in which said cross-sectional area is the shape of an ellipse.

12. A system in accordance with claim 10 in which said cross-sectional area is the shape of a rectangle.

13. A system in accordance with claim 1 in which said lumen has an input section and an output section, said input section connected to said constricted section by a converging section and said constricted section connected to said output section by a diverging section.

14. A system in accordance with claim 13 in which said converging section converges with said constricted section at an angle of no greater than 5 degrees relative to the longitudinal axis of said lumen.

15. A system in accordance with claim 13 in which said converging section converges with said constricted section at an angle of no greater than 5 degrees relative to the longitudinal axis of said lumen and in which said diverging section diverges from said constricted section at an angle of no greater than 5 degrees relative to the longitudinal axis of said lumen.

16. A system in accordance with claim 13 in which said converging section converges with said constricted section at an angle of no greater than 2.5 degrees relative to the longitudinal axis of said lumen.

17. A system in accordance with claim 13 in which said converging section converges with said constricted section at an angle of no greater than 2.5 degrees relative to the longitudinal axis of said lumen and in which said diverging section diverges from said constricted section at an angle of no greater than 2.5 degrees relative to the longitudinal axis of said lumen.

18. A system in accordance with claim 1 in which said sensor means has a cavity located adjacent said constricted section area in said electromagnetic field.

19. A system in accordance with claim 18 in which the dimension of said cavity perpendicular to the blood flow in said lumen is greater than the length of the cross-sectional area of said constricted cross-sectional area.

20. A system in accordance with claim 19 in which said cavity is the form of a cylinder and the cavity is positioned in said sensor means with the central axis of said cavity perpendicular to said blood flow in said lumen.

4. A system in accordance with claim in which said first electromagnetic focus means is mounted on said transducer.

21. A disposable blood flow sensor for a magnetic blood flow system employing a magnetic field between a pair of magnetic poles which comprises a body portion constructed of non-magnetic and non-conductive material, said body portion having a lumen extending along a longitudinal axis of said body portion from an input section to an output section to direct blood through said body portion, said lumen having a constricted section intermediate said input section and output an electromagnetic field focus means associated with said body portion and in alignment with the constricted section of lumen, said sensor being positioned between said magnetic poles with said constricted section of said lumen intersecting said magnetic field and a pair of electrical terminal means mounted in said body portion and communicating with said constricted section of said lumen to detect an electromotive force generated by the flow of blood in said lumen through said magnetic field.

22. A sensor in accordance with claim 21 in which said constricted section has a cross-sectional area with a length greater than the cross-sectional width.

23. A sensor in accordance with claim 22 in which said cross-sectional area is the shape of an ellipse.

24. A sensor in accordance with claim 22 in which said cross-sectional area is the shape of a rectangle.

25. A sensor in accordance with claim 21 in which said lumen has a converging section which interconnects said input section and said constricted section and which further includes a diverging section interconnecting said constricted section and said output section.

26. A sensor in accordance with claim 25 in which said converging section converges with said constricted section at an angle of no greater than 2.5 degrees, relative to the longitudinal axis of said lumen

27. A sensor in accordance with claim 25 in which said converging section converges with said constricted section at an angle of no greater than 2.5 degrees relative to the longitudinal axis of said lumen and in which said diverging section diverges from said constricted section at an angle of no greater than 2.5 degrees relative to the longitudinal axis of said lumen.

28. A sensor in accordance with claim 25 in which said converging section converges with said constricted section at an angle of no greater than 5 degrees relative to the longitudinal axis of said lumen.

29. A sensor in accordance with claim 25 in which said converging section converges with said constricted section at an angle of no greater than 5 degrees relative to the longitudinal axis of said lumen and in which said diverging section diverges from said constricted section at an angle of no greater than 5 degrees relative to the longitudinal axis of said lumen.

30. A sensor in accordance with claim 21 which further includes a cavity in said body portion positioned in a location of said body portion adjacent said constricted section and a magnetic field focus means mounted in said cavity to focus said magnetic field when said body portion is positioned in said magnetic field.

31. A sensor in accordance with claim 21 which further includes first and second cavities in said body portion, each of said cavities positioned on opposing sides of said body portion and on opposing sides of said constricted section, and in which said focus means includes magnetic field focus devices mounted in each of said first and second cavities to focus said magnetic field when said body portion is positioned in said magnetic field.

32. A sensor in accordance with claim 21 in which said constricted cross-sectional area has a cross-sectional length greater than the cross-sectional width and in which said electrical terminal means are mounted at the extremity of said length of said cross-sectional area

33. A sensor in accordance with claim 32 in which said cross-sectional area is the shape of a rectangle.

34. A sensor in accordance with claim 32 in which said cross-sectional area is the shape of an ellipse.

35. A sensor in accordance with claim 30 in which the dimension of said cavity perpendicular to the blood flow in said lumen is greater than the length of the cross-sectional area of said constricted cross-sectional area.