JPS6014176Y2 - electromagnetic flow meter - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic flowmeter, and particularly relates to an improvement in the magnetic pole of an electromagnetic flowmeter that includes a magnetic pole that also serves as an outer casing.

Figure 1 shows the general structure of this type of electromagnetic flowmeter.
1 is a non-magnetic measuring tube through which fluid passes, 2゜2' is a magnetic pole that also serves as an outer casing, 3 and 3' are coils that generate magnetic flux, 4.4
' is an outer casing which also serves as a core, and 6 is an electrode installed orthogonally to the tube axis of the measuring tube 1.

Conventionally, ductile cast iron has often been used for the magnetic poles 2 and 2', which also serve as the outer casing, but in this case, the coil-wound part of the magnetic pole has thick sluices and cracks, resulting in manufacturing problems. In addition to being difficult, the properties of each part of the magnetic pole are not uniform, and the magnetic flux density is not uniform when generating a magnetic field, and its distribution is varied, making it difficult to obtain an electromagnetic flowmeter with good linearity and characteristics against drift. The disadvantage was that it could not be done.

An object of the present invention is to provide an electromagnetic flowmeter that eliminates the above-mentioned drawbacks.

For this reason, in the present invention, the coil-wound part of the magnetic pole that also serves as the outer casing is formed into a frame shape with an open end face on the measuring tube side to make the plate thickness uniform, and a magnetic material is placed so as to cover the open end of the frame shape. The intended purpose was distantly achieved by attaching a magnetic pole plate to the magnetic pole.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing an embodiment of the electromagnetic flowmeter according to the present invention.

Note that parts equivalent to those in FIG. 1 are given the same reference numerals and explanations will be omitted.

In FIG. 2, the coil-wound portions 12a and 12'a of the magnetic poles 12 and 12', which also serve as outer casings, are formed into a frame shape with the center portion removed and the end face on the measuring tube side open.

Then, magnetic pole plates 15, 15' made of a magnetic material such as a silicon steel plate or a mild steel plate are removably attached to the magnetic poles 12, 12', which also serve as outer casings, by screws or the like so as to cover this frame-shaped opening end.

The magnetic pole plates 15° and 15' are as shown in FIG.
If you use a plate with a uniform thickness, the magnetic pole 1 that also serves as the outer casing
The magnetic flux distribution generated at 2 and 12' becomes uniform as shown in FIG.

In the electromagnetic flowmeter of the present invention and embodiment formed in this way, the coil winding portion 12a of the magnetic pole 12, 12' which also serves as the outer casing.
Since the thickness of v 12'a has been removed and the overall plate thickness has been made uniform, there will be no cracking, making it easier to manufacture, and the magnetic pole plate 15.15' has uniform properties on the pole end surface. By attaching it, a uniform magnetic flux density is obtained, the magnetic flux distribution is stabilized, and the characteristics are improved.

Furthermore, in the electromagnetic flowmeter according to the present invention, when installing the electromagnetic flowmeter, if it is not possible to have a sufficiently long straight pipe section upstream and downstream, simply change the magnetic pole plate 15.15' as shown below. This has the advantage that it can be handled by changing the magnetic flux distribution of the generated magnetic field.

That is, if there is not a straight pipe section of sufficient length above and downstream of the electromagnetic flowmeter, the fluid flowing in the measuring pipe 1 will cause a biased flow.

It is known that in such cases, accurate measurement can be achieved by making the magnetic flux distribution non-uniform, such as a functional distribution magnetic field.

Conventionally, the magnetic flux distribution as described above was obtained by changing the shape of the coil, but in the electromagnetic flowmeter according to the present invention, as shown in FIG. By forming holes with appropriate shapes and dimensions, a magnetic field with an intensity distribution as shown in FIG. 4 can be generated.

As described in detail above, according to the present invention, the thick part of the magnetic pole that also serves as the outer casing is eliminated, making manufacturing easier without the occurrence of cracks. By changing the shape of the magnetic pole plate attached to the end face, a desired magnetic flux distribution can be obtained, and an electromagnetic flowmeter that can easily adapt to installation conditions and enable highly accurate measurement can be provided.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example of an electromagnetic flowmeter equipped with magnetic poles that also serve as an outer casing, Fig. 2 is a sectional view showing an example of an electromagnetic flowmeter according to the present invention, and Figs. 3a and 3b are FIG. 2 is a cross-sectional view of an embodiment of the magnetic pole plate used in the electromagnetic flowmeter shown in FIG. 2, and a diagram showing the generated magnetic flux distribution. FIGS. FIG. 2 is a diagram showing a cross-sectional view of the magnetic flux and the generated magnetic flux distribution. 1...Measuring tube, 12.12'...Magnetic pole that also serves as outer casing, 12at 12'a...Coil winding part, 3゜3'... ...Phil, 4...
・Core that also serves as outer casing, 15.15'...magnetic pole plate, 6...electrode.

Claims (1)

[Scope of utility model registration request] A measuring tube through which fluid passes, a pair of electrodes installed perpendicular to the tube axis on this measuring tube, and a magnetic pole that also serves as a coil and an outer casing that generate a magnetic field orthogonal to a line connecting the pair of electrodes. In an electromagnetic flowmeter, the coil-wound part of the magnetic pole that also serves as the outer casing is formed into a frame shape with an open end on the measurement tube side, and a magnetic pole plate made of a magnetic material is attached to the outer housing so as to cover the open end of the frame. An electromagnetic flowmeter characterized by being removably attached to a magnetic pole that also serves as a casing.