Measuring and testing – Volume or rate of flow – By measuring electrical or magnetic properties
Patent
1990-07-18
1992-06-16
Eisenzopf, Reinhard J.
Measuring and testing
Volume or rate of flow
By measuring electrical or magnetic properties
G01F 158
Patent
active
051216400
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to an electromagnetic flow meter, comprising a metering tube having a thick outer wall made of an electrically non-conducting material. It has at least two measuring electrodes and at least two magnetic poles, each of which is disposed in a blind bore of the metering tube. They are linked to one another by a yoke and have at least one magnetic coil.
In a known magnetic-inductive flow meter, as described for example in German patent publication DE-OS 15 73 066, the yoke linking the magnetic poles is disposed outside the periphery or outer surface of the metering tube. Such an arrangement requires an inordinate amount of space for the yoke and, for small diameters, results in significant losses of magnetic flux and a reduced sensitivity. These drawbacks are also encountered with arrangements in which the cores of the magnetic coils are mounted on a ferromagnetic housing for the magnetic reflux (cf. EP 0047342 B1; U.S. Pat. No. 4,089,113; German Patent DE 35 11 033).
SUMMARY OF THE INVENTION
To overcome these drawbacks the present invention places the yoke and the magnetic coils into a recess inside the outer wall of the metering tube.
Positioning the yoke and the excitation coil inside the tube renders the magnetic circuit significantly more stable and increases the measurement accuracy. Moreover, the magnet components require no additional space. Thus, such instruments are significantly more compact.
Placing the yoke and the magnetic coil inside the metering tube makes it easier to conform the instrument to special design requirements and facilitates its manufacture. In a simple embodiment of the invention, a midportion of the yoke which supports the magnetic coil is disposed inside a through hole which extends parallel to the blind bores for the magnetic poles. An intermediate section of the yoke, which connects the midportion to the magnetic poles, is disposed in grooves in the exterior surface of the metering tube. In a more developed embodiment of the invention, multiple through holes in the metering tube extend parallel to the blind bores for the magnet poles. In this manner, one or more yokes can optionally be inserted into or extended through the holes as desired.
In another simple embodiment of the invention, the midportion of the yoke mounting the magnetic coils is placed inside a semi-circular groove which extends between the blind bores. This permits insertion of the yoke and the magnetic coils into the groove from the outside.
The magnetic coils may be constructed as required by the surroundings and operational considerations. For example, the magnetic poles may be connected with two arcuate yokes which are parallel to one another. To enhance the magnetic flux, the yoke can be extended through multiple, successive bores and provided with multiple coil windings.
To facilitate the installation of the magnet components in the bore or grooves, the yoke is preferably constructed of two or more sections that can be inserted into and assembled in the holes and/or grooves.
BRIEF DESCRIPTION OF THE DRAWINGS
Multiple embodiments of the present invention are shown in the below, in which,
FIG. 1 is a side elevational view of a metering tube,
FIG. 2 is a cross-section taken at a midportion of the tube of FIG. 1 and shows the magnetic poles and a yoke,
FIG. 3 is a plan view of the tube of FIG. 1,
FIG. 4 is a second embodiment of a metering tube,
FIG. 5 is a cross-section taken at a midportion of the tube of FIG. 4 and shows the magnetic poles and a yoke,
FIG. 6 is a cross-section of a third embodiment of the present invention and shows the magnetic poles and a yoke, and
FIG. 7 is a perspective view of a yoke provided with three magnetic coils.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A metering tube 1 for a magnetically inductive flow meter as shown in FIG. 1-3 is constructed of an electrically non-conductive material such as plastic, ceramic or the like. It has a cylindrical shape and an axial flow-through bore 2. The metering tube has an especially
REFERENCES:
patent: 4181018 (1980-01-01), Schmoock
patent: 4774844 (1988-10-01), Davis
Eisenzopf Reinhard J.
Krohne AG
Shopbell E.
LandOfFree
Electromagnetic flow meter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electromagnetic flow meter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electromagnetic flow meter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1747584