JP2590920Y2 - Electromagnetic flow meter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flow meter for measuring a flow rate of a conductive fluid flowing in a measuring pipe.

[0002]

2. Description of the Related Art An electromagnetic flowmeter measures the flow rate of a conductive fluid flowing in a measuring tube by converting the flow rate into an electric signal using an electromagnetic induction phenomenon, and is generally constructed as shown in FIGS. ing. That is, 1 is a flange 1a at both ends,
1b, which is a measuring pipe which is flange-connected in the middle of a pipe 3 through which the fluid 2 to be measured flows, and a pair of magnetic fields formed on the outer periphery of the measuring pipe 1 in a direction perpendicular to the flow direction of the fluid 2 to be measured. Saddle-type excitation coils 4A and 4B are provided to face each other. Further, a pair of electrodes 5A is provided on the outer periphery of the central portion of the measuring tube 1,
5B (5B is not shown) is provided so as to face the magnetic field at right angles to the magnetic field, and its inner end faces the pipe 6 and is in contact with the fluid 2 to be measured. On the other hand, the outer ends of the electrodes 5A, 5B are connected by signal lead wires 9 to a converter 8 provided on the outer periphery of the measuring tube 1 via a cover 7. The inner wall of the measurement tube 1 and the outer surface of the flange are lined with a lining material 10 made of a fluororesin, neoprene, or the like to provide electrical insulation and corrosion resistance, and are insulated from the fluid 2 to be measured. The measurement pipe 1 and the pipe 3 have their flange surfaces joined to each other via an earth ring 11 and a gasket 12.

[0003] The earth ring 11 grounds the measurement tube 1 and the fluid 2 to be measured to make them equal in potential, and thereby the fluid 2 to be measured is
Has a function of eliminating noise generated due to an unstable electric potential and a function of protecting the lining material 10. Such an earth ring 11 is usually made of stainless steel 316 or the like, but if corrosion resistance and wear resistance are required, it is made of a noble metal such as platinum, titanium, monel, and hastelloy. The earth ring 11
A pair of fixing portions 14 having screw mounting holes 15 on the outer periphery
a, 14b are integrally extended, and
a and 14b are fixed to the flange surface of the measuring tube 1 or the outer peripheral surface of the flange portion 1a by set screws 16, thereby electrically connecting the earth ring 11 and the measuring tube 1 to each other.

[0004]

As described above, in the conventional electromagnetic flowmeter 17, when corrosion resistance and wear resistance are required, special materials such as platinum, titanium, monel, hastelloy, etc. are used as the material of the earth ring 11. I use metal,
These precious metals are expensive.Especially when manufacturing a large-diameter earth ring, the electromagnetic flowmeter itself becomes extremely expensive.Thus, the plate thickness is reduced, unnecessary parts are cut, and material costs are reduced. But the strength is weak and the piping 3
When the electromagnetic flow meter 17 is attached to and detached from the
When a force is applied to the fixing portions 14a and 14b, the fixing portions 14
cracks 18 at the bases of the
a and 14b were damaged.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to prevent the fixing portion from being damaged and to use a gasket.
An object of the present invention is to provide an electromagnetic flowmeter capable of reliably positioning .

[0006]

This invention SUMMARY OF THE INVENTION has been made in order to achieve the above object, the at least one end of the measuring tube
Equipped with an earth ring that is attached and comes in contact with the conductive fluid to be measured.
In the electromagnetic flowmeter obtained above, the inner diameter of the
A first ring to be liquefied, and a diameter larger than the inner diameter of the first ring;
Metal with a smaller inside diameter than the outside diameter of the first ring
A second ring, wherein the first ring and the second ring are
And fix the gasket inside the inner diameter of the second ring.
It is made possible to wear .

[0007]

In the present invention, the first ring is joined to the second ring, so that the minimum size and thickness required for liquid contact are sufficient, and the material used is saved. The gasket is positioned and fitted within the inner diameter of the second ring , the first ring
Close to .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a sectional view showing an embodiment of an electromagnetic flow meter provided with an earth ring according to the present invention, and FIG. 2 is a front view of the earth ring. In the drawings, the same components as those in FIGS. 3 and 4 are denoted by the same reference numerals, and the description thereof will be omitted. In these figures, in this embodiment, the earth ring 20 inserted along with the gasket 12 between the flange surfaces of the measuring pipe 1 and the pipe 3 is replaced with two rings having different materials and sizes, that is, a first ring 21 and a second ring 21. , 2
2. The first ring 21 is made of a noble metal such as platinum, titanium, tantalum, hastelloy or the like having excellent corrosion resistance and wear resistance, and has a thickness of 0.1 to 0.1 mm.
The inner diameter is set to be about 2 mm, which is substantially equal to the inner diameter of the measuring tube 1. The second ring 22 is made of an inexpensive material having a large mechanical strength, for example, stainless steel 316, and has a plate thickness of about 3 mm, an inner diameter and an outer diameter larger than the inner diameter and the outer diameter of the first ring 21, and an outer periphery. The fixing portions 14a and 14b each having the screw mounting hole 15 are integrally extended. The first ring 21 and the second ring 22 are integrally joined by being coaxially overlapped and welded or seam-welded. In this case, the inner diameter of the first ring 21 is smaller than the inner diameter of the second ring 22. Therefore, the center side of the second ring side surface of the first ring 21 is
Is not joined, and is left as the contact surface 23 of the gasket 12. The gasket 12 is formed in a ring shape by rubber or the like, and has an appropriate plate thickness, an inner diameter substantially equal to the inner diameter of the first ring 21, and an outer diameter substantially equal to the inner diameter of the second ring 22. The gasket contact surface 2 of the first ring 21 is positioned by being fitted into the center hole 24 of the
3 closely. The earth ring 20 configured as described above is inserted between the flange surface of the measurement pipe 1 and the pipe 3 together with the gasket 12 with the first ring 21 facing the measurement pipe 1, and the second ring 22 is fixed. The parts 14a, 14b are respectively set by the set screw 16 to the flange part 1 of the measuring tube 1.
fixed to a.

As described above, in the present invention, the earth ring 20 is composed of the first ring 21 made of an expensive noble metal and the second ring 22 made of a material that is inexpensive and has high mechanical strength. Since the first ring 21 is fixed to the measuring tube 1, no mechanical strength is required for the first ring 21, and the first ring 21 can be made thin to have a minimum size necessary for liquid contact.
Further, the second ring 22 has a large mechanical strength,
It is possible to prevent the fixing portions 14a and 14b from being damaged or cracked when the measuring tube 1 is detached from the pipe. Further, the hole diameter of the first ring 21 is set smaller than the hole diameter of the second ring 22, and the gasket 12 is connected to the second ring 22.
Of the first ring 21 and the gasket contact surface 23, so that the center of the earth ring 20 and the center of the gasket 12 can be easily and reliably aligned. Can be done.

[0010]

[Effects of the Invention] As described above, the electromagnetic current according to the present invention is
According to the meter, the first ring and the second ring are joined to each other to form an earth ring, the first ring is brought into contact with the liquid,
Since the ring is fixed to the measuring tube, the first ring does not require mechanical strength, it can be made thinner and the minimum size required for liquid contact can be achieved, and the material cost is lower than that of the conventional noble metal earth ring. Can be greatly reduced. Also, the second
By forming the ring with a material having high strength, there is no risk that the fixing portion will be cracked or the fixing portion will be damaged even if a force is applied to the pipe when attaching and detaching the pipe, thereby improving the durability of the earth ring. Can be. In addition, the gasket must be securely positioned by the inner diameter of the second ring.
Since it is, such as to allow an accurate flow rate measurement, its practical effect is large.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an electromagnetic flowmeter using an earth ring according to the present invention.

FIG. 2 is a front view of the grounding ring according to the present invention.

FIG. 3 is a sectional view showing a conventional example of an electromagnetic flowmeter provided with a conventional earth ring.

FIG. 4 is a front view of a conventional earth ring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring tube 1a, 1b Flange 4A, 4B Excitation coil 5A Electrode 8 Converter 10 Lining material 11 Earth ring 12 Gasket 17 Electromagnetic flow meter 20 Earth ring 21 First ring 22 Second ring 23 Gasket contact surface

Claims (1)

(57) [Scope of request for utility model registration] An electromagnetic flow provided with an earth ring attached to at least one end of a measuring tube and in contact with a conductive fluid to be measured.
A first ring made of a corrosion-resistant metal and having an inner diameter in contact with a liquid;
Larger than the inner diameter of the first ring and larger than the outer diameter of the first ring
A second ring made of metal having a small inner diameter,
The first ring and the second ring are laminated and fixed to each other, and the second ring is fixed.
The feature is that a gasket can be placed inside the inside diameter of the
Electromagnetic flow meter.