Flow sensor assembly

• US 4,942,763 A
• Filed: 03/23/1988
• Issued: 07/24/1990
• Est. Priority Date: 03/23/1988
• Status: Expired due to Fees

• Current Assignee: Harpster, Joseph W.
• Original Assignee: Harpster, Joseph W.
• Inventors: Harpster, Joseph W.
• Primary Examiner(s): Goldstein, Herbert
• Application Number:
  US07/172,030
• Time in Patent Office: 853 Days
• Field of Search: 73/189, 73/198, 73/202, 73/204, 73/861.83, 73/861.92, 73/204.21, 73/204.22, 73/204.25, 73/204.27, 73/202.5
• US Class Current: 73/202.5
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01F 1/6842 with means for influencing the fluid flow
• CPC Class Codes: G01F 5/00 Measuring a proportion of the volume flow

Abstract

A flow sensor assembly particularly suited for measuring localized flow components within a region of flow which may exhibit flow components of varying velocity vector in both intensities and directions. The assembly includes a sampling conduit which confronts the localized flow and, through an entrance partitioning arrangement, develops a sampling flow therethrough representing the product of the cosine of the angle of incidence of the intercepted flow with the axis of the sensing channel. A flow sensor is positioned within the sampling flow to provide a readout of the velocity thereof. The apparatus can be mounted on a movable probe and employed to determine the intensity and direct of localized fluid flow components within larger regions of flow.

Claims

1. Apparatus for determining the mass transport of fluid within a conduit, said fluid having a mass transport vector along the axis of said conduit, said mass transport vector being derived from localized components of fluid flow each exhibiting a local flow velocity vector, comprising:

sampling conduit means having a flow axis, positioned within said conduit and having an entrance opening of area extent selected to confront and sample an incident front area of fluid representing a said localized component of fluid flow and said component of fluid flow exhibiting a said local flow velocity vector incident to said flow axis at an angle θ

, for admitting that portion of said component as sampled fluid flow;

entrance partitioner means comprising a plurality of conduits positioned within said sampling conduit means, each having a principal cross-sectional dimension, and extending therein a predetermined length from said entrance opening to an end location, said predetermined length being selected as a multiple of said principal dimension effective to intercept discrete portions of said component of fluid flow and alter the direction of flow thereof to a direction substantially parallel with said sampling conduit means flow axis and exhibiting a velocity substantially corresponding with the product of said local flow velocity vector and the cosine of said angle θ

;

flow sensor means mounted with said sampling conduit means and responsive to said sampled fluid flow for deriving an output signal corresponding therewith; and

means defining a flow chamber intermediate said flow sensor means and said entrance partitioner means end location for effecting the derivation of a substantially uniform profile of velocity of said sampled fluid flow at said flow sensor means.

2. The apparatus of claim 1 in which said entrance partitioner means predetermined length is about four times said principal dimension of said conduits thereof.

3. The apparatus of claim 1 including exit partitioner means positioned within said sampling conduit means downstream from said flow sensor means for preventing interference to said sampled fluid flow deriving from dynamic phenomena within said region of fluid movement external to said sampling conduit means.

4. The apparatus of claim 3 in which said exit partitioner means comprises a plurality of conduits having hexagonal cross-sections.

5. The apparatus of claim 3 in which said exit partitioner means comprises a plurality of conduits formed as cylindrical tubes.

6. The apparatus of claim 1 in which said entrance partitioner means discrete conduits comprise a sequence of parallel flat vanes.

7. The apparatus of claim 1 in which said entrance partitioner means discrete conduits comprise a plurality of internested said conduits having rectangular cross sections.

8. The apparatus of claim 1 in which said entrance partitioner means discrete conduits comprise a plurality of internested cylindrical tubes.

9. The apparatus of claim 1 in which said entrance partitioner means conduits comprise a plurality of internested said conduits having hexagonal cross-sections.

10. The apparatus of claim 1 in which said sensor means comprises:

first probe means extending within said sampling channel at said predetermined location;

first thermally responsive sensor means mounted with said first probe means for deriving a first signal representing the thermal condition of said sensor means as influenced by said sample flow;

heater means mounted with said first probe means for thermally influencing said first thermally responsive sensor means in a manner wherein the residual temperature deriving said thermal influence varies as an exponential relationship between said first sensor means and said heater means;

second probe means extending within said sampling channel at said predetermined location and spaced from said first probe means;

second thermally responsive sensor means mounted with said second probe means for deriving a reference output signal representing a thermal condition of said sample flow; and

comparison means responsive to said reference output signal and said first signal for deriving an output representing the rate of flow of said sample flow.

11. Flow sensor apparatus positionable within a conduit carrying fluid moving therewithin along a mass transport axis and exhibiting localized components of flow having velocity vectors at angles θ

incident to said transport axis, comprising;

sampling conduit means having an entrance opening of area extent selected to confront a said localized component of flow, having a sampling channel defining a flow axis parallel with said mass transport axis extending to an exit opening and configured for developing a sample flow at a predetermined location within said sampling channel;

entrance partitioner means having a plurality of conduits each having a principal cross-sectional dimension positioned within said sampling channel and extending a predetermined length selected as a multiple of said principal dimension effective to intercept discrete portions of said localized component of flow and alter the direction thereof to a direction substantially parallel with said flow axis and exhibiting a flow velocity corresponding with the product of said localized component velocity vector incident upon said entrance opening and the cosine of its said angle θ

; and

flow sensor means positioned within said sampling channel at said predetermined location and responsive to said fluid sample flow thereat for deriving an output signal corresponding therewith.

12. The flow sensor of claim 11 including means defining a flow chamber extending between said sampling channel predetermined location and said entrance partitioner means end location for effecting the derivation of a substantially uniform profile of velocity of fluid flowing at said sensor means.

13. The flow sensor of claim 11 in which said entrance partitioner means discrete conduits comprise a sequence of parallel flat vanes.

14. The flow sensor of claim 11 in which said entrance partitioner means discrete conduits comprise a plurality of internested said conduits having rectangular cross sections.

15. The flow sensor of claim 11 in which said entrance partitioner means discrete conduits comprise a plurality of internested said conduits having hexagonal cross-sections.

16. The flow sensor of claim 11 in which said entrance partitioner means discrete conduits comprise a plurality of internested cylindrical tubes.

17. The flow sensor of claim 11 including exit partitioner means positioned within said sampling channel and extending from said exit opening a predetermined distance toward said predetermined location for preventing interference to said sample flow deriving from dynamic flow phenomena within said conduit carrying fluid external to said sampling conduit means.

18. The flow sensor of claim 17 in which said exit partitioner means comprises a plurality of conduits having hexagonal cross-sections.

19. The flow sensor of claim 17 in which said exit partitioner means are formed as a plurality of cylindrical tubes.

20. The flow sensor of claim 11 in which said sensor means comprises:

first probe means extending within said sampling channel at said predetermined location;

first thermally responsive sensor means mounted with said first probe means for deriving a first signal representing the thermal condition of said sensor means as influenced by said sample flow;

heater means mounted with said first probe means for thermally influencing said first thermally responsive sensor means in a manner wherein the residual temperature deriving said thermal influence varies as an exponential relationship between said first sensor means and said heater means;

second probe means extending within said sampling channel at said predetermined location and spaced from said first probe means;

second thermally responsive sensor means mounted with said second probe means for deriving a reference output signal representing a thermal condition of said sample flow; and

comparison means responsive to said reference output signal and said first signal for deriving an output representing the rate of flow of said sample flow.

21. The method for determining the mass transport of fluid flowing within a conduit and having a mass transport vector along the axis of said conduit, said mass transport vector being derived from localized components of fluid flow, each exhibiting a local flow velocity vector at an angle θ

with respect to said conduit axis, comprising the steps of;

providing a sampling conduit having an entrance opening of area extent selected to confront and define a said localized component of said fluid flow exhibting substantially uniform local flow velocity, and having a sampling channel extending along a channel axis from said entrance opening to an exit opening;

positioning said sampling conduit to intercept said localized fluid flow and in an orientation wherein said channel axis is parallel with said conduit axis;

partitioning said intercepted fluid flow upon the entry thereof through said entrance opening by locating a plurality of partitioning conduits within said sampling conduit, each said partitioning conduit having a principal cross-sectional dimension and intercepting a discrete portion of said intercepted fluid flow and each partitioning conduit extending from said entrance opening to an end location representing a length selected as a multiple of said principal dimension effective to derive a fluid flow exhibiting a flow vector substantially parallel with said sampling axis and having a sampled flow velocity vector of magnitude corresponding with the product of said local flow velocity vector and the cosine of said angle θ

;

positioning a flow sensor within said sampling channel at a location to measure said fluid flow having said sampled flow velocity vector, said location being spaced from said end location of said partitioning conduits to define a flow chamber of extent deriving a substantially uniform profile of velocity of said intercepted fluid flow at said flow sensor; and

deriving a flow velocity output from said positioned flow sensor.

22. The method of claim 21 including the steps of:

providing an exit partitioner extending into said sampling channel from said exit opening for preventing interference to fluid flow at said flow sensor location deriving from dynamic flow phenomena external to said sampling conduit in the vicinity of said exit opening.

23. Apparatus for detecting the direction of a localized component of fluid flow within a region of movement of said fluid, comprising:

a positioning rod having an end positionable within said region of fluid movement;

sampling conduit means mounted to have a predetermined orientation at said rod end and movable therewith for positioning within said localized component of fluid flow and having an entrance opening of select area extent, a sampling channel defining a flow axis corresponding with said predetermined orientation extending to an exit opening and configured for developing a sample flow at a predetermined location within said sampling channel;

entrance partitioner means comprising a plurality of conduits, each having a principal cross-sectional dimension, positioned within said sampling channel and extending therein a predetermined length from said entrance opening to an end location, said predetermined length being selected as a multiple of said principal dimension effective to intercept discrete portions of said localized component of fluid flow and alter the direction of flow thereof to a direction substantially parallel with said sampling channel flow axis and having a flow velocity corresponding with the product of the vector of flow velocity of said localized component incident upon said entrance opening and the cosine of said angle of incidence with respect to said sampling channel flow axis;

flow sensor means poistioned within said sampling channel at said predetermined location and responsive to said fluid sample flow thereat for deriving an output signal corresponding therewith;

means defining a flow chamber extending between said sampling channel predetermined location and said entrance partitioner means end location for effecting the derivation of a substantially uniform profile of velocity of fluid flowing at said sensor means; and

manipulative means for effecting the movement of said positioning rod to maneuver said sampling conduit means into a position wherein the value of said cosine approaches unity and for determining the orientation of said vector of said flow velocity at said position.

24. The flow sensor of claim 23 in which said entrance partitioner means discrete conduits comprise a plurality of internested said conduits having hexagonal cross-sections.

25. The flow sensor of claim 23 including exit partitioner means positioned within said sampling channel and extending from said exit opening a predetermined distance toward said predetermined location for preventing interference to said sample flow deriving from dynamic flow phenomena within said conduit carrying fluid external to said sampling conduit means.

26. The flow sensor of claim 25 in which said exit partitioner means comprises a plurality of conduits positioned within said sampling channel and having hexagonal cross-sections.

27. A flow sensor assembly for positioning within a region of fluid flow, comprising:

a sensor support mountable within said region of fluid flow, having an external surface, an internally disposed conduit extending along a support axis for protectively supporting electrical leads and selectively positioned conduit opening communicating with said conduit through said surface;

an annular, externally threaded mount having a base fixed to said support external surface, a top surface, a centrally disposed cylindrical surface opening extending from said top surface therethrough and positioned over said conduit opening;

a cylindrical sampling conduit support slideably insertable within said mount cylindrically surface opening, supportable therefrom, and having internally disposed channel means for effecting access with said sensor support conduit through said conduit opening;

sampling conduit means for sampling a localized component of said fluid flow along a sampling flow axis, said sampling conduit means being mounted upon and supported by said cylindrical sampling conduit support;

flow sensor means mounted within said sampling conduit means and responsive to said sampled fluid flow for deriving an output signal corresponding therewith at electrical output leads extensible through said internally disposed channel means and said sensor support internally disposed conduit for readout access without said region of fluid flow;

compliant sealing means positioned at said mount top surface in contact with said cylindrical conduit support;

an annular, internally threaded retainer cap theadably engageable with said externally threaded mount and slideably positionable about said cylindrical sampling conduit support for effecting the retention thereof within said annular mount by compressible engagement with said compliant sealing means.

28. The flow sensor assembly of claim 27 in which said compliant means is an O-ring.

29. The flow sensor assembly of claim 27 in which:

said annular externally threaded mount includes an alignment insert extending inwardly from said centrally disposed opening; and

said cylindrical sampling conduit support is configured having a slot slidable over and engageable with said alignment insert for securing said conduit support against rotation.

30. The flow sensor assembly of claim 27 in which said sampling conduit means includes an entrance opening of area extent selected to confront said localized component of said fluid flow impinging thereon at a given angle of incidence, and having a sampling channel extending along said sampling flow axis to an exit opening and configured for developing a sample flow at a predetermined location within said sampling channel having a flow velocity corresponding with the product of the flow velocity of said localized component and the cosine of said angle of incidence;

and

said flow sensor means is mounted at said predetermined location.

31. The flow sensor assembly of claim 30 including entrance partitioner means positioned within said sampling channel and extending a predetermined length therein from said entrance opening to an end location for intercepting discrete portions of said localized component of flow and altering the direction thereof to a direction substantially parallel with said flow axis.

32. The flow sensor of claim 31 including means defining a flow chamber extending between said sampling channel predetermined location and said entrance partitioner means end location for effecting the derivation of a substantially uniform profile of velocity of fluid flowing at said sensor means.

33. The flow sensor of claim 31 including exit partitioner means positioned within said sampling conduit means downstream from said flow sensor means for preventing interference to said sampled fluid flow deriving from dynamic phenomena within said region of fluid movement external to said sampling conduit means.

34. Apparatus for detecting the direction of a localized component of flow within a region of movement of said fluid, comprising:

a positioning rod having an end positionable within said region of fluid movement;

sampling conduit means mounted to have a predetermined orientation at said rod end and movable therewith for positioning within said localized component of fluid flow and having an entrance opening of select area extent, a sampling channel defining a flow axis corresponding with said predetermined orientation extending to an exit opening and configured for developing a sample flow at a predetermined location within said sampling channel;

entrance partitioner means comprising a plurality of conduits, each having a principal cross-sectional dimension, positioned within said sampling channel and extending therein a predetermined length from said entrance opening to an end location, said predetermined length being selected as about four times said principal dimension for intercepting discrete portions of said localized component of fluid flow and altering the direction of flow thereof to a direction substantially parallel with said sampling channel flow axis and having a flow velocity corresponding with the product of the vector of flow velocity of said localized component incident upon said entrance opening and the cosine of said angle of incidence with respect to said sampling channel flow axis;

flow sensor means positioned within said sampling channel at said predetermined location and responsive to said fluid sample flow thereat for deriving an output signal corresponding therewith;

means defining a flow chamber extending between said sampling channel predetermined location and said entrance partitioner means end location for effecting the derivation of a substantially uniform profile of velocity of fluid flowing at said sensor means; and

manipulative means for effecting the movement of said positioning rod to maneuver said sampling conduit means into a position wherein the value of said cosine approaches unity and for determining the orientation of said vector of said flow velocity at said position.

35. Flow sensor apparatus positionable within a conduit carrying fluid moving therewithin along a mass transport axis and exhibiting localized components of flow having velocity vectors at angle θ

incident to said transport axis, comprising;

sampling conduit means having an entrance opening of area extent selected to confront a said localized component of flow, having a sampling channel defining a flow axis parallel with said mass transport axis, extending to an exit opening and configured for developing a sample flow at a predetermined location within said sampling channel;

entrance partitioner means having a plurality of conduits each having a principal cross-sectional dimension positioned within said sampling channel and extending a predetermined length of about four times said principal dimension for intercepting discrete portions of said localized component of flow and altering the direction thereof to a direction substantially parallel with said flow axis and exhibiting a flow velocity corresponding with the product of said localized component velocity vector incident upon said entrance opening and the cosine of said incident angle, θ

; and

flow sensor means positioned within said sampling channel at said predetermined location and responsive to said fluid sample flow thereat for deriving an output signal corresponding therewith.

36. Apparatus for determining the mass transport of fluid within a conduit, said fluid having a mass transport vector along the axis of said conduit, said mass transport vector being derived from localized components of fluid flow, each exhibiting a local flow velocity vector, comprising:

sampling conduit means having a flow axis positioned within said conduit and having an entrance opening of area extent selected to confront and sample an incident front area of fluid representing a said localized component of fluid flow and said component of fluid flow exhibiting a said local flow velocity vector incident to said flow axis at an angle, θ

, for admitting that portion of said component as sampled fluid flow;

entrance partitioner means comprising a plurality of conduits positioned within said sampling conduit means, each having a principal cross-sectional dimension, and extending therein a predetermined length from said entrance opening to an end location, said predetermined length being about four times said principal dimension, for intercepting discrete portions of said component of fluid flow and altering the direction of flow thereof to a direction substantially parallel with said sampling conduit means flow axis and exhibiting a velocity substantially corresponding with the product of said local flow velocity vector and the cosine of said angle θ

;

flow sensor means mounted with said sampling conduit means and responsive to said sampled fluid flow for deriving an output signal corresponding therewith; and

means defining a flow chamber intermediate said flow sensor means and said entrance partitioner means and the location for effecting the derivation of a substantially uniform profile of velocity of said sampled fluid flow at said sensor means.