JPS596408Y2 - electromagnetic flow meter - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic flowmeter, and particularly to an improvement of a core that shapes the return path of magnetic flux.

Magnetic flowmeters generally require a core to form a return path for magnetic flux to improve excitation efficiency.

The core used is a ring-shaped core made by winding silica steel plates in multiple layers, which generate less eddy current.

The annular core is fixed to the inner surface of the outer casing by fasteners such as bolts or nuts, either directly or via spacers.

Such an electromagnetic flowmeter has the disadvantage that it requires a lot of man-hours and parts to attach the annular core.

A core wound in multiple layers is not only relatively difficult to handle, but also
It is not easy to securely fix the core so that it does not displace or vibrate due to vibrations.

For this reason, an electromagnetic flowmeter with a large diameter necessarily requires a large number of fasteners, which is also disadvantageous because it increases leakage of magnetic flux to the outer casing.

The present invention eliminates the above-mentioned drawbacks, significantly reduces the number of parts and man-hours for attaching the annular core, and provides an electromagnetic flowmeter with good excitation efficiency.

According to the present invention, the annular core is made of a single layer of magnetic material,
In addition, a gap is formed between the device and the outer casing, and a protrusion is partially fixed to the inner surface of the outer casing.

In other words, since the protrusion can be fixed to the inner surface of the outer casing by means such as welding or hammering, not only can the number of parts and man-hours be reduced, but the annular core can be disposed with a gap from the outer casing as a whole. Therefore, the magnetic flux leaking to the outer casing can be reduced, and an electromagnetic flowmeter with good excitation efficiency can be provided.

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

1 and 2, reference numeral 1 denotes a non-magnetic conduit forming a fluid flow path, such as a stainless steel pipe, and this conduit has a pair of electrically insulated electrodes 2, 2 on its diameter.
is installed.

Excitation coils 3, 3 are attached to the outer periphery of the conduit 1 so as to form magnetic flux in directions perpendicular to the axis of the conduit and the line connecting the pair of electrodes 2, 2.

The excitation coils 3, 3 consist of a pair of loops and are fixed to the conduit by adhesive or by suitable metal fittings (not shown).

Flange pipes 4, 4 are provided at both ends of the conduit 1.
O-ring packings 5,5 are inserted between the outer periphery of the flange pipes 4, and the inner peripheries of the flange pipes 4,4.

An outer casing 6 is welded to the flange tubes 7 to house the excitation coils 3, 3 inside the flange tubes 4, 4.

An annular core 7 is provided on the inner surface of the outer casing 6 so as to surround the excitation coils 3, 3.

Further, the inner surface of the conduit 1 is provided with a lining 8 made of an electrically insulating material such as rubber.

Both ends of the lining 8 extend sideways across the flange pipe 4 and are held down by earth rings 9, 9.

According to the present invention, the annular core 7 uses a magnetic material having a higher magnetic permeability than the outer casing 6, such as a relatively thin single-layer diatomaceous steel plate.

A gap of an appropriate size is formed between the annular core 7 and the inner surface of the outer casing 6, and the annular core 7 has protrusions 7a that are partially ejected outward. It is fixed to the inner surface of 6.

Welding or anchor driving can be used as the fixing means.

Figure 3 shows an annular core 7 made by bending a single layer of magnetic material.
An embodiment of the present invention is shown, which is fixed to the outer casing 6 at the protrusion, that is, the corner 7a.

In the present invention, since the annular core 7 is made of a single layer of magnetic material as described above, it is relatively easy to handle, and the protrusion 7
Since it is fixed to the outer casing 6 by a, it can be firmly fixed.

Furthermore, the number of parts and man-hours required to attach the annular core 7 is relatively small, and there is almost no fear that the core 7 will be displaced or vibrated due to vibrations, impacts, etc., which helps improve accuracy and reliability.

Further, since the annular core 7 is attached to the outer casing 6 with a gap as a whole, the magnetic flux is less likely to leak to the outer casing 6, and the excitation efficiency is good.

Particularly in the rectangular wave excitation method, there is an advantage that the transition time of the rise and fall of the magnetic flux can be shortened.

[Brief explanation of the drawing]

Fig. 1 is a partially cross-sectional side view of an electromagnetic flowmeter according to the present invention, Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1, and Fig. 3 is an enlarged cross-section of the outer casing and core portion according to an embodiment of the present invention. It is a diagram. 1... Conduit, 2... Electrode, 3...
... Excitation coil, 6 ... Outer casing, 7 ...
Annular core, 7a... protrusion.

Claims (1)

[Scope of utility model registration request] A conduit that forms a fluid flow path, a pair of mutually opposing electrodes attached to this conduit, and a magnetic flux that is perpendicular to the axis of the conduit and a line connecting the pair of electrodes. The conduit includes an excitation coil attached to the outer periphery of the conduit, an annular core made of a single layer of magnetic material surrounding the excitation coil, and an outer casing surrounding the outside of the annular core, and between the annular core and the outer casing. An electromagnetic flowmeter characterized in that a gap is formed and the annular core has a protrusion partially fixed to the inner surface of the outer casing.