Method and apparatus for determining the direction and rate of a rotating element

• US 6,604,434 B1
• Filed: 06/23/2000
• Issued: 08/12/2003
• Est. Priority Date: 06/23/2000
• Status: Expired due to Term

• Current Assignee: Neptune Technology Group Incorporated (Roper Technologies, Inc.)
• Original Assignee: Neptune Technology Group Incorporated (Roper Technologies, Inc.)
• Inventors: Hamilton, David, Castleberry, Walter, Scarborough, John
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Mack, Corey D.
• Application Number:
  US09/602,038
• Time in Patent Office: 1,145 Days
• Field of Search: 738/617.5, 738/617.7, 738/618.3, 738/618.7, 738/618.8, 738/618.9, 738/619.4, 738/61, 324/207.21, 324/207.2, 324/207.25, 324/165, 324/166, 324/173, 324/174
• US Class Current: 73/861.75
• CPC Class Codes: G01F 1/075 with magnetic or electromagnetic coupling to the indicating device
• CPC Class Codes: G01F 15/066 involving magnetic transmission devices
• CPC Class Codes: G01F 3/12 Meters with nutating members, e.g. discs

Abstract

The present invention provides a device for measuring both the magnitude of rotation of a rotating magnetic field as well as the direction of rotation of a rotating magnetic field. The present invention may be used to measure the magnitude and direction of fluid flow by converting the kinetic energy of a moving fluid into a rotating magnetic field. At least two stationary sensors are placed in the magnetic field to detect the resulting changes in magnetic flux polarity occurring and provide therefrom a determination of the magnitude and direction of fluid flow.

Claims

1. A method of determining the direction of rotation of a rotating magnetic field, comprising:

sensing the change in polarity of magnetic flux encountered at a first point located within the rotating magnetic field with a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell;

sensing the change in polarity of magnetic flux encountered at a second point located within the rotating magnetic field with a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, wherein said second point is located at a position that is subsequent in the direction of rotation from said first point;

creating a first stream of signals corresponding to said change in polarity of magnetic flux at said first point;

creating a second stream of signals corresponding to said change in polarity of magnetic flux at said second point; and

determining the direction of rotation of the magnetic field by comparing the change in polarity detected at said first point with the change in polarity detected at said second point.

2. A method of determining the direction of rotation of a rotating magnetic field as in claim 1, wherein

said first point is located within a first plane that is coincident with the axis about which said magnetic field is rotating;

said second point is located within a second plane that is coincident with the axis about which said magnetic field is rotating; and

said first plane and said second plane form an angle of about 45 degrees from each other.

3. A method for determining the direction of rotation of a rotating magnetic field as in claim 1, wherein the rotating magnetic field is created by a rotating magnet that is in mechanical communication with a rotating measuring element located in the path of a flowing fluid.

4. A method of determining the direction of rotation of a rotating magnetic field as in claim 3, wherein the rotating magnet is cylindrically shaped and contains four separated poles.

5. A method of sensing the rotation and direction of a rotating magnetic field, comprising:

detecting the changes in polarity of magnetic flux encountered at a first point located within the rotating magnetic field with a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell;

creating a first stream of electrical pulses of alternating polarity corresponding to the changes in polarity of magnetic flux detected at said first point;

detecting the changes in polarity of magnetic flux encountered at a second point located within the rotating magnetic field with a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, wherein said second point is located at a position that is subsequent in the direction of rotation from said first point;

creating a second stream of electrical pulses of alternating polarity corresponding to the changes in polarity of magnetic flux detected at said second point;

converting said first stream of electrical pulses into a first alternating high and low signal;

converting said second stream of electrical pulses into a second alternating high and low signal; and

decoding said first and second alternating high and low signals to determine the number of rotations and direction of said rotating magnetic field.

6. A method of sensing the rotation and direction of a rotating magnetic field as in claim 5, wherein

said first point is located within a first plane that is coincident with the axis about which said magnetic field is rotating;

said second point is located within a second plane that is coincident with the axis about which said magnetic field is rotating; and

said first plane and said second plane form an angle of about 45 degrees from each other.

7. A method of sensing the rotation and direction of a rotating magnetic field as in claim 5, wherein the rotating magnetic field is created by a rotating magnet that is in mechanical communication with a rotating measuring element located in the path of a flowing fluid.

8. A method of sensing the rotation and direction of a rotating magnetic field as in claim 7, wherein the rotating magnet is cylindrically shaped and contains four separated poles.

9. A method of sensing the rotation and direction of a rotating magnetic field, comprising the steps of:

generating a first series of alternating electrical signals in sequence with the alternating changes in magnetic flux polarity occurring at a first position within said rotating magnetic field with a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, said first series of signals being generated as the changes in magnetic flux polarity occur and being of alternating polarity;

generating a second series of alternating electrical signals in sequence with the alternating changes in magnetic flux polarity occurring at a second position within said rotating magnetic field with a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, said second series of signals being generated as the changes in magnetic flux polarity occur and being of alternating polarity, said second position being located subsequent in the direction of rotation from said first position; and

combining said first signal and said second signal so as to create a first output indicating the amount of rotation of said magnetic field and a second output indicating the direction of rotation of said magnetic field.

10. A method as in claim 9, wherein the steps of combining of said first signal and said second signal comprises:

converting said first series of alternating electrical signals into a first pulse train of positive pulses;

converting said second series of alternating electrical signals into a second pulse train of positive pulses;

translating said first pulse train into a first channel of alternating high and low output, said first channel of alternating high and low output being in sequence with the positive pulses of said first pulse train;

translating said second pulse train into a second channel of alternating high and low output, said second channel of alternating high and low output being in sequence with the positive pulses of said second pulse train; and

decoding said first and second channels of alternating high and low output so as to create said first output indicating the amount of rotation of said magnetic field and said second output indicating the direction of rotation of said magnetic field.

11. A method as in claim 9, wherein

said first point is located within a first plane that is coincident with the axis about which said magnetic field is rotating;

said second point is located within a second plane that is coincident with the axis about which said magnetic field is rotating; and

said first plane and said second plane form an angle of about 45 degrees from each other.

12. A method as in claim 9, wherein the rotating magnetic field is created by a rotating magnet that is in mechanical communication with a rotating measuring element located in the path of a flowing fluid.

13. A method as in claim 9, wherein said rotating magnet is cylindrically shaped and contains four separated poles, and wherein said angle between said first plane and said second plane is about 45 degrees.

14. A fluid meter for determining the rate and direction of a fluid flow, comprising:

a magnet that is rotatable about an axis, said magnet configured such that upon rotation a field of changing magnetic flux polarity is created;

a measuring element in mechanical communication with said magnet and configured such that upon being placed into the path of fluid flow said measuring element translates the kinetic energy of the moving fluid so as to cause said magnet to rotate about the axis;

a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, placed within the field of magnetic flux of said magnet, said first bistable ferromagnetic wire being configured for detecting the changes in magnetic flux polarity occurring upon the rotation of said magnet and providing a first series of signals representing the changes in magnetic flux polarity, said first bistable ferromagnetic wire being located within a first plane that is coincident with the axis about which said magnet is rotatable;

a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, placed within the field of magnetic flux of said magnet, said second bistable ferromagnetic wire being configured for detecting the changes in magnetic flux polarity occurring upon the rotation of said magnet and providing a second series of signals representing the changes in magnetic flux polarity, said second bistable ferromagnetic wire being located within a second plane that is coincident with the axis about which said magnet is rotatable, wherein said first plane and said second plane form an angle greater than 0 degrees; and

means configured for receiving and interpreting said first and second series of signals so as to determining the direction and amount of fluid flow.

15. A fluid meter as in claim 14, wherein said means comprises:

a first rectifier for receiving said first series of signals and converting the same into a first pulse train of positive pulses and a second pulse train of positive pulses representing said first series of signals;

a second rectifier for receiving said second series of signals and converting the same into a third pulse train of positive pulses and a fourth pulse train of positive pulses representing said second series of signals;

a first translator including circuitry for receiving said first and second pulse train and translating the same into a first channel of alternating high and low signals representing said first and second pulse train;

a second translator including circuitry for receiving said third and fourth pulse train and translating the same into a second channel of alternating high and low signals representing said third and fourth pulse train; and

decoding circuitry for receiving said first and second channel and determining therefrom the direction and amount of fluid flow.

16. A fluid meter as in claim 14, wherein said angle between said first plane and said second plane is about 45 degrees.

17. A fluid meter as in claim 14, wherein said magnet is cylindrically shaped and further comprises at least 4 poles.

18. A device for measuring fluid flow, comprising:

a first chamber defining a fluid inlet and a fluid outlet;

a measuring element configured within said first chamber such that a fluid passing through said first chamber causes said measuring element to rotate;

a magnet having a centerline and being in mechanical communication with said measuring element such that said magnet rotates with said element about the centerline of said magnet;

a second chamber attached to said first chamber; and

a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, positioned within said second chamber and within the field of magnetic flux of said magnet such that upon said magnet rotating, said first bistable ferromagnetic wire detects the resulting changes in polarity of magnetic flux and provides a first series of alternating electrical pulses corresponding to said changes in polarity detected by said first bistable ferromagnetic wire;

a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, positioned within said second chamber and within the field of magnetic flux of said magnet such that upon said magnetic rotating, said second bistable ferromagnetic wire detects the resulting changes in polarity of magnetic flux and provides a second series of alternating electrical pulses corresponding to said changes in polarity detected by said second bistable ferromagnetic wire, said second bistable ferromagnetic wire being positioned relative to said first bistable ferromagnetic wire such that said second bistable ferromagnetic wire does not simultaneously detect the same change in magnetic flux being detected by said first bistable ferromagnetic wire; and

means in communication with said first and said second bistable ferromagnetic wires, said means configured for receiving and interpreting said first and second series of electrical pulses so as to determine the direction and magnitude of fluid flow.

19. A device as in claim 18, wherein said means in communication with said first bistable ferromagnetic wire and said second bistable ferromagnetic wire comprises:

a first circuit for transposing said first series of alternating electrical pulses into a first pulse train of positive pulses and a second pulse train of positive pulses corresponding to said first series of alternating electrical pulses;

a second circuit for transposing said second series of alternating electrical pulses into a third pulse train of positive pulses and a fourth pulse train of positive pulses corresponding to said second series of alternating electrical pulses;

a third circuit for converting said first and second pulse train into a first channel of alternating high and low states representing said first and second pulse train;

a fourth circuit for converting said third and fourth pulse train into a second channel of alternating high and low states representing said third and fourth pulse train; and

a fifth circuit for receiving said first and second channel and determining therefrom the direction and magnitude of fluid flow.

20. A device as in claim 18, wherein said magnet comprises a cylindrically-shaped disk.

21. A device as in claim 18, wherein said magnet has at least four poles.

22. A fluid flow meter, comprising:

a housing, said housing defining a fluid inlet and a fluid outlet;

a magnet located within said housing and being rotatable about an axis;

means for causing said magnet to rotate about the axis as a fluid flows through said housing;

a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, positioned within the field of magnetic flux of said magnet, said bistable ferromagnetic wire being located within a first plane coincident with the axis;

a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, positioned within the field of magnetic flux of said magnet, said second bistable ferromagnetic wire being located within a second plane coincident with the axis, wherein said first plane and said second plane are at angle greater than zero degrees; and

circuitry in communication with said first and second bistable ferromagnetic wires and configured such that the magnitude of rotation and direction of rotation of said magnet may be determined.

23. A fluid flow meter as in claim 22, wherein said magnet is cylindrically shaped.

24. A fluid flow meter as in claim 23, wherein said magnet comprises at least four poles.

25. A device for measuring fluid flow, comprising:

a first chamber defining a fluid inlet and a fluid outlet;

a rotatable, magnetic member configured within said first chamber such that a fluid passing through said first chamber causes said member to rotate about an axis;

a second chamber attached to said first chamber;

a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity that the shell, positioned within said second chamber, said first bistable ferromagnetic wire being located within a first plane coincident with said axis and configured for sensing and detecting the changes in polarity of magnetic flux generated upon the rotation of said magnetic member;

a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity that the shell, positioned within said second chamber, said first bistable ferromagnetic wire being located within a second plane coincident with said axis, wherein said first plane and said second plane are at angle greater than zero degrees, said second bistable ferromagnetic wire being configured for sensing and detecting the changes in polarity of magnetic flux generated upon the rotation of said magnetic member; and

circuitry in communication with said first and second bistable ferromagnetic wires, said circuitry configured such that the magnitude of rotation and direction of rotation of said rotatable, magnetic member may be determined.

26. A device for measuring fluid flow, comprising:

a first housing defining a fluid inlet arid a fluid outlet;

a first magnet configured within said first housing such that a fluid passing through said first housing causes said first magnet to rotate;

a second housing attached to said first housing;

a second magnetic field located within said second housing, said second magnet being in magnetic communication with said first magnet such that said second magnet rotates about an axis as said first magnet rotates;

a first bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, positioned within said second housing, said first bistable ferromagnetic wire being located within a first plane coincident with said axis and configured for sensing and detecting the changes in polarity of magnetic flux generated upon the rotation of said second magnet about said axis;

a second bistable ferromagnetic wire that comprises a core and a shell, wherein the core has a higher coercivity than the shell, positioned within said second housing, said bistable ferromagnetic wire being located within a second plane coincident with said axis, wherein said first plane and said second plane are at angle greater than zero degrees, said second bistable ferromagnetic wire being configured for sensing and detecting the changes in polarity of magnetic flux generated upon the rotation of said second magnet about said axis; and

circuitry in communication with said first and second bistable ferromagnetic wires and configured such that the magnitude of rotation and direction of rotation of said second magnet may be determined.

27. A device for measuring fluid flow as in claim 26, wherein said first and second magnets are cylindrical in shape.