Abstract
A magnetically inductive flow measuring probe comprises a housing that is adapted to be exposed to the medium; two measuring electrodes arranged in a housing end section for forming a galvanic contact with the medium and for sensing a voltage induced in the flowing medium; and a means for producing a magnetic field passing through the housing end section. The means includes a coil arrangement and a field guide body. The field guide body comprises two field guide body legs connected with a coil core, extending to a front section of the housing and adapted to serve as field guideback. Orthogonal projections of the measuring electrodes and the field guide body onto a cross sectional plane are disjoint.
Claims
1-11. (canceled)
12. A magnetically inductive flow measuring probe for insertion into an opening of a pipeline flowed through by a flowable medium and for ascertaining a flow-velocity-dependent measured variable of a flowable medium, the magnetically inductive flow measuring probe comprising: a housing that is adapted to be exposed to the medium, the housing having: a housing end section; and a housing case that encloses a housing interior; two measuring electrodes arranged in the housing end section for forming a galvanic contact with the medium and for sensing a voltage induced in the flowing medium, wherein each of the two measuring electrodes) has a measuring electrode contact element protruding inwardly into the housing interior, wherein the two measuring electrode contact elements are arranged such that a housing longitudinal plane extends through the two measuring electrode contact elements; a means for producing a magnetic field that passes through the housing end section, wherein the means for producing the magnetic field is arranged in the housing interior and includes a coil arrangement and a field guide body, wherein the coil arrangement includes an opening, and the field guide body includes a coil core that extends through the opening in the coil arrangement, wherein the field guide body includes two field guide body legs connected with the coil core and extending to a front section of the housing and adapted to serve as a field guideback, wherein orthogonal projections of the measuring electrodes and the field guide body onto a cross sectional plane are disjoint.
13. The magnetically inductive flow measuring probe as claimed in claim 12, wherein a field guide body longitudinal plane extends through the two field guide body legs, and wherein the housing longitudinal plane and field guide body longitudinal plane define an angle β with 0°<β≤90°.
14. The magnetically inductive flow measuring probe as claimed in claim 13, wherein the field guide body legs are, at least partially, strip shaped, and/or wherein the field guide body has exactly two mutually perpendicular mirror planes, and one of the two mirror planes and the field guide body longitudinal plane coincide.
15. The magnetically inductive flow measuring probe as claimed in claim 13, wherein the coil arrangement includes a coil, a coil support and two coil contact elements, wherein the coil contact elements are connected with a coil wire wound on the coil support and forming the coil, wherein the two coil contact elements are arranged on the coil support on a side far from the housing end section, wherein a coil arrangement longitudinal plane extends through the two coil contact elements, wherein a field guide body longitudinal plane extends through the two field guide body legs, and wherein the field guide body longitudinal plane and the coil arrangement longitudinal plane define an angle α with 0°≤α≤90°.
16. The magnetically inductive flow measuring probe as claimed in claim 15, wherein a line of intersection of the housing longitudinal plane and the field guide body longitudinal plane coincides with a longitudinal axis of the housing, and/or wherein a line of intersection of the housing longitudinal plane and the coil arrangement longitudinal plane coincides with the longitudinal axis of the housing.
17. The magnetically inductive flow measuring probe as claimed in claim 12, further comprising: a measuring circuit for ascertaining a measurement voltage induced on the two measuring electrodes, wherein the measuring circuit is arranged in the housing interior and separably connected with the measuring electrode contact elements mechanically and electrically, and wherein the measuring circuit is arranged on a circuit board and the circuit board has measuring electrode counter contact elements embodied complementary to the measuring electrode contact elements and embodied to form a plug-in connection with the measuring electrode contact elements.
18. The magnetically inductive flow measuring probe as claimed in claim 17, further comprising: an operating circuit for operating the coil arrangement, wherein the operating circuit is arranged in the housing interior and separably connected with the coil arrangement mechanically and electrically, wherein the operating circuit is arranged on a circuit board, and the circuit board has coil counter contact elements embodied complementary to the coil contact elements, and wherein the coil counter contact elements form a plug-in connection with the coil contact elements.
19. The magnetically inductive flow measuring probe as claimed in claim 18, wherein the circuit board has two circuit board legs with, in each case, a circuit board leg end section, wherein the circuit board legs extend from a circuit board main body in a direction of the front section of the housing, wherein the two measuring electrode counter contact elements are arranged, in each case, in a different one of the two circuit board leg end sections.
20. The magnetically inductive flow measuring probe as claimed in claim 19, wherein the two coil counter contact elements are arranged on the circuit board main body.
21. The magnetically inductive flow measuring probe as claimed in claim 20, wherein the circuit board has two sides facing away from one another, wherein the coil counter contact elements are arranged, in each case, on different sides of the circuit board, and/or wherein the measuring electrode counter contact elements are arranged, in each case, on different sides of the circuit board.
22. The magnetically inductive flow measuring probe as claimed in claim 20, wherein the circuit board has two sides facing away from one another, wherein the coil counter contact elements are arranged, in each case, on same sides of the circuit board, and/or wherein the measuring electrode counter contact elements are arranged, in each case, on same sides of the circuit board.
Description
[0069] The invention will now be explained in greater detail based on the appended drawing, the figures of which show as follows:
[0070] FIG. 1 a perspective and partially sectioned view of a magnetically inductive flow measuring probe according to the state of the art;
[0071] FIG. 2 a perspective view of a first embodiment of the magnetically inductive flow measuring probe of the invention;
[0072] FIG. 3 a perspective view of the first embodiment with arranged circuit board;
[0073] FIG. 4 a plan view of an orthogonal projection of the measuring electrodes and the field guide body onto a cross sectional plane perpendicular to the longitudinal axis of the housing of the first embodiment;
[0074] FIG. 5 a plan view of an orthogonal projection of the measuring electrodes and the field guide body onto a cross sectional plane perpendicular to the longitudinal axis of the housing of a second embodiment; and
[0075] FIG. 6 a schematic view of the magnetically inductive flow measuring probe of the invention in a pipeline.
[0076] Based on the perspective and partially sectioned view of the FIG. 1, first, the measuring principle underlying the invention will be explained. A magnetically inductive flow measuring probe 1 includes an, in general, circularly cylindrical housing 2 having a predetermined outer diameter. The housing is fitted to the diameter of a bore, which is located in a wall of a pipeline 8 (not shown in FIG. 1, but shown in FIG. 6) and into which the magnetically inductive flow measuring probe 1 is fluid-tightly inserted. Flowing in the pipeline 8 is a flowable medium to be measured, into which the flow measuring probe 1 is immersed essentially perpendicularly to the flow direction of the medium, as shown by the wavy arrows 18. A housing end section 16 of the housing 2 protruding into the medium is fluid-tightly sealed with a front body 15 of insulating material. A means 5 arranged in the housing 2 for producing a magnetic field produces a magnetic field 9 passing through the end section and into the medium. A coil core 1 at least partially of a soft magnetic material arranged in the housing 2, or a pole shoe 12 located terminally on the coil core 11, ends at or in the vicinity of the housing end section 16. A field guideback 26 having a field guideback body 14, which surrounds the coil arrangement 6 and the coil core 11, is adapted to lead the magnetic field 9 extending out of the housing end section 16 back into the housing 2. The coil core 11, the pole shoe 12 and the field guideback body 14 are, in each case, field guide bodies 10, which together form a field guide arrangement. First and second galvanic measuring electrodes 3, 4 are arranged in the front body 15 and contact the medium. An electrical voltage induced on the measuring electrodes 3, 4 according to Faraday's law of induction can be read by means of a measuring circuit. The voltage is maximum, when the flow measuring probe is so installed into the pipeline that a plane defined by a straight line intersecting the two measuring electrodes 3, 4 and a longitudinal axis of the flow measuring probe extends perpendicularly to the flow direction 18, or to the longitudinal axis of the pipeline. An operating circuit 7 is electrically connected with the coil arrangement 6, especially with the coil 13, and is adapted to impress on the coil 13 a clocked excitation signal, in order, thus, to produce a clocked magnetic field 9.
[0077] FIG. 2 shows a perspective view of a part of a first embodiment of the magnetically inductive flow measuring probe of the invention. Shown is a front body 15 with arranged measuring electrodes and the measuring electrode contact elements 28.1, 28.2 of the two measuring electrodes. The measuring electrode contact elements 28.1, 28.2 and the measuring electrodes can be embodied as a number of parts or as single pieces. The measuring electrode contact elements 28.1, 28.2 can also be formed by end sections of the measuring electrodes. Arranged on a media far side of the front body 15 is a means 5 for producing a magnetic field passing through the front body 15. The means 5 for producing the magnetic field includes a coil arrangement of a coil 13 and a coil support 24. Coil 13 is composed of a coil wire wound on the coil support 24. The ends of the coil wire are, in each case, connected with coil contact elements 31.1, 31.2 or form, in each case, the coil contact elements 31.1, 31.2. The coil contact elements 31.1, 31.2 extend essentially in parallel with a longitudinal axis of the housing. Additionally, the means 5 for producing the magnetic field includes a field guide body composed of two field guide body legs 25.1, 25.2 and a coil core, which extends through an opening of the coil support 24. The two field guide body legs 25.1, 25.2 are connected with an end of the coil core. The illustrated embodiment shows a monolithic field guide body. Alternatively, the field guide body can be made of a plurality of parts, i.e. coil core and field guide body legs 25 are individual components, which are assembled and together form the field guide body. The coil support 24 and the front body 15 can be separate parts or they can be formed monolithically.
[0078] FIG. 3 shows a perspective view of a part of the first embodiment with applied circuit board. In addition to the features of FIG. 2, the shown part of the magnetically inductive flow measuring probe of the invention includes supplementally a circuit board 34, which has two coil counter contact elements 36.1, 36.2 (36.2 is hidden in FIG. 3 by the circuit board) and two measuring electrode counter contact elements 35.1, 35.2. Circuit board 34 includes two circuit board legs 37.1, 37.2, which extend from a circuit board main body 39 in the direction of the front body. The circuit board legs 37.1, 37.2 have, in each case, a circuit board leg end section 38, where, in each case, a measuring electrode counter contact element 35.1, 35.2 is arranged. The coil counter contact elements 36.1, 36.2 are arranged on the circuit board main body 39. In the illustrated embodiment, the coil counter contact elements 36.1, 36.2 form a plug-in connection with the coil contact elements and the measuring electrode counter contact elements 35.1, 35.2 form a plug-in connection with the measuring electrode contact elements. Arranged on the circuit board 34 is an operating circuit 7 and a measuring circuit 33, wherein the operating circuit 7 is electrically connected with the coil via the coil counter contact elements 36.1, 36.2 and the measuring circuit 33 is electrically connected with the measuring electrodes via the measuring electrode counter contact elements 35.1, 35.2.
[0079] FIG. 4 shows a first plan view of an orthogonal projection of the measuring electrodes and the field guide body onto a cross sectional plane perpendicular to the longitudinal axis of the housing of the first embodiment. The dot dashed lines represent, respectively, the housing longitudinal plane 29, the field guide body longitudinal plane 30 and the coil arrangement longitudinal plane 32. Between the housing longitudinal plane 29 and the field guide body longitudinal plane 30 is an angle β. According to the invention, 0°<β≤90°, especially 10°≤β≤60° and preferably 25°≤β≤45°. The angle β of the illustrated embodiment is about 35°. Between the field guide body longitudinal plane 30 and the coil arrangement longitudinal plane 32 is an angle α, wherein 0°≤α≤90°, especially α≥50° and preferably α≥75°. The angle β is so selected that the measuring electrode contact elements 28 are not hidden by the field guide body and, at the same time, the magnetic field produced between the measuring electrodes is sufficiently large, in order to induce in the medium a measurement voltage detectable by means for ascertaining the induced measurement voltage. The first and second plan views differ in that in the second plan view a circuit board 34 with measuring electrode counter contact elements 35 and coil counter contact elements 36 is plugged onto the front body 15, in order that the coil contact elements 31 and measuring electrode contact element 28 are electrically connected, respectively, with the operating circuit 7 and the measuring circuit 33. The two coil counter contact elements 36 are arranged on different sides of the circuit board 34. The same is true also for the arrangement of the two measuring electrode counter contact elements 35.
[0080] FIG. 5 shows a plan view of an orthogonal projection of the measuring electrodes and the field guide body on a cross sectional plane perpendicularly to the longitudinal axis of the housing for a second embodiment. The dot dashed lines represent, respectively, the housing longitudinal plane 29, the field guide body longitudinal plane 30 and the coil arrangement longitudinal plane 32. Between the housing longitudinal plane 29 and the field guide body longitudinal plane 30 is an angle β. According to the invention, 0°<β≤90°, especially 10°≤β≤60° and preferably 25°≤β≤45°. Between the field guide body longitudinal plane 30 and the coil arrangement longitudinal plane 32 is an angle α, wherein 0°≤α≤90°, especially α≥50° and preferably α≥75°. In the illustrated embodiment, the angles α and β are selected equal, in order to achieve an independence of circuit board tolerance, especially circuit board thickness. For such purpose, also two measuring electrode counter contact elements 35 and two coil counter contact elements 36 are arranged on a shared side of the circuit board 34.
[0081] FIG. 6 shows a schematic view of a measuring setup with a magnetically inductive flow measuring probe 1 of the invention inserted in a pipeline 8 having a longitudinal axis 21. A medium-contacting section of the housing is embodied electrically conductively and arranged as reference electrode 17.
LIST OF REFERENCE CHARACTERS
[0082] 1 magnetically inductive flow measuring probe
[0083] 2 housing
[0084] 3 measuring electrode
[0085] 4 measuring electrode
[0086] 5 means for producing a magnetic field
[0087] 6 coil arrangement
[0088] 7 operating circuit
[0089] 8 pipeline
[0090] 9 magnetic field
[0091] 10 field guide body
[0092] 11 coil core
[0093] 12 pole shoe
[0094] 13 coil
[0095] 14 field guideback body
[0096] 15 front body
[0097] 16 housing end section
[0098] 17 reference electrode
[0099] 18 flow direction of the medium
[0100] 21 pipeline longitudinal axis
[0101] 24 coil support
[0102] 25 field guide body leg
[0103] 26 field guideback
[0104] 27 cross sectional plane
[0105] 28 measuring electrode contact element
[0106] 29 housing longitudinal plane
[0107] 30 field guide body longitudinal plane
[0108] 31 coil contact elements
[0109] 32 coil arrangement longitudinal plane
[0110] 33 measuring circuit
[0111] 34 circuit board
[0112] 35 measuring electrode counter contact elements
[0113] 36 coil counter contact elements
[0114] 37 circuit board leg
[0115] 38 circuit board leg end section
[0116] 39 circuit board main body
