JPS645209Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a small-diameter electromagnetic flowmeter, and particularly has a structure that allows a required magnetic field to be easily obtained even in a small-diameter flowmeter.

Figure 1 shows a half-cut cross-sectional view of a small-diameter (diameter of 25 mm or less) electromagnetic flowmeter transmitter. As shown in the figure, four flange bolt holes 2 having a substantially circular shape are provided in a spool 3 around the pipe line 1 along the pipe axis direction. This flange bolt hole 2
The electromagnetic flowmeter transmitter and the piping are connected by.
In addition, a pair of electrodes 4 are provided in the horizontal direction (horizontal direction in the figure) of the conduit 1 so as to be perpendicular to the tube axis and facing each other (FIG. 1 shows an extrapolation type case). ) Further, in the vertical direction of the conduit 1, a magnetic field generating device constituted by an elongated ball piece 5 and a coil 6 is provided in the space between the flange bolt holes 2. The reason why this magnetic field generator is provided in an elongated manner in the vertical direction of the pipe line 1 is that although the smaller the diameter, the stronger the magnetic field is required, the pipe line 1
This is because the electrodes 4 are provided in the left and right direction and there is no space. In addition, 7 in the figure is a housing.

However, the electromagnetic flowmeter having such a structure has the following drawbacks.

Since it has a structure in which electrodes are provided in the horizontal direction and magnetic field generators are provided in the vertical direction, the structure of the spool and housing is complicated, and it is difficult to achieve the dimensional accuracy required in casting processing.

Since the diameter of the ball piece cannot be increased due to restrictions on the position of the flange bolt holes, the magnetic field distribution tends to spread outward as shown in Figure 2, making it difficult to obtain the required magnetic field. .

The cost of lining the inner peripheral surface of the spool conduit increases, and in the case of a small diameter, it is difficult to line the spool concentrically with the inner diameter of the spool conduit by molding. Incidentally, this eccentricity of the lining causes eccentricity of the electrode axis, which is also a cause of measurement errors.

Therefore, in view of the drawbacks of the above-mentioned conventional technology, the present invention is
It is an object of the present invention to provide an electromagnetic flowmeter having a structure that allows a required magnetic field strength to be easily obtained even in the case of a small diameter and is easy to manufacture. The structure of the present invention that achieves this object is such that a body equipped with a pipe line and an electrode perpendicular to the pipe line can be installed in an area where a connecting through bolt of a mating pipe is not located,
A coil for generating a magnetic field and a ball piece are provided in this body, extending along the axial direction of the electrode and the axial direction of the conduit, and the outer periphery of this body is covered with a metal housing. .

An embodiment of the present invention will be described below based on the drawings. In this embodiment, a case will be described in which the present invention is applied to an electromagnetic flowmeter having a diameter of about 10 mm or less and equipped with an extrapolation type electrode.

A plan view of the electromagnetic flowmeter of this example is shown in Figure 3a.
Its AA sectional view is shown in FIG. 3b. As shown in both figures, the body 11 has a conduit 10 in the center made of an insulating material such as corrosion-resistant plastic or ceramics.
is formed. Holes 12 for electrode insertion are provided on both sides of the conduit 10 in the horizontal direction perpendicular to the tube axis (in the left-right direction in the figure). 15. Further, the body 11 of the transmitter has a flat flange contact surface 17 that abuts against the flange 16 of the mating piping, and the flange 16 of the mating piping
They are interposed therebetween and connected by bolts 16a. Furthermore, counterbore holes 18 are provided above and below the conduit 10, respectively, and extend in the electrode axis direction and the tube axis direction, and a ball piece 19 and a coil 20 are placed in the space inside the counterbore holes 18. It is housed and installed to constitute a magnetic field generating device. Furthermore, this body 11 is covered with a metal housing 21 whose outer periphery is magnetic, and the overall thickness (the dimension in the vertical direction in the figure) is as shown in FIG.
It is formed to have a thickness sufficient to allow it to be placed between the lower bolts 16a.

In addition, in the embodiment shown in FIG. 3b, the electrode 13
Although a structure is shown in which the electrode cannot be pulled out of the housing 21, it may be replaced from the outside by providing an electrode cover 22 with a screw fitting part as shown in FIG. Also, housing 2
As shown in Fig. 5, 1 may be divided into two parts on a plane including the electrode axis and the tube axis, and a flange 23 may be provided at the joint part, and the two parts may be joined together by bolts. Electrodes can be easily replaced.

As explained above with reference to the embodiments, according to the present invention, the magnetic flux leaking to the outside of the measurement pipe is reduced, so the required magnetic field strength can be achieved with a disk-shaped coil having a smaller cross-sectional area than a conventional cylindrical coil. can be obtained easily. In addition, since the coil has a flat shape,
A planar sheet coil with a laminated structure can be used as is. Furthermore, the spool and lining
Since it can be molded as a one-piece body from an insulating material such as plastic or ceramics, technical and application problems associated with linings can be avoided. Furthermore, since the wall thickness of the body can be made sufficiently thick, it is possible to create a structure that can sufficiently withstand the flange tightening pressure from the mating piping.

[Brief explanation of the drawing]

Figures 1 and 2 relate to conventional examples; Figure 1 is a cross-sectional view showing a small-diameter electromagnetic flowmeter transmitter; Figure 2 is a schematic diagram illustrating magnetic field distribution; Figures 3a to 5; The figures relate to an embodiment of the present invention, and FIG. 3a is a plan view of an electromagnetic flowmeter transmitter, FIG. 3b is a sectional view taken along the line A-A in FIG. 3a, and FIGS. 4 and 5. FIG. 3 is a cross-sectional view showing other embodiments of the casing structure. In the drawing, 10 is a conduit, 11 is a body (insulator),
13 is the electrode, 16 is the flange of the mating pipe, 16a
is a pipe connection bolt, 17 is a flange contact surface, 1
9 is a ball piece, 20 is a coil, 21 is a housing, 22 is an electrode cover, and 23 is a flange of the housing.

Claims (1)

[Scope of utility model registration request] A body including a conduit and an electrode orthogonal to the conduit is formed so as to be installable in an area where a connecting through bolt of a mating conduit is not located, and the body is provided with an axial direction of the electrode and an axis of the conduit. An electromagnetic flowmeter characterized in that it is provided with a coil for generating a magnetic field and a ball piece that are spread along the direction, and the outer periphery of this body is covered with a metal housing.