JP3227687B2 - Earth ring for pipeline - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth ring for a pipe used for an electromagnetic flow meter, for example, and more particularly to a method for reducing cracks generated at the end of a ceramic pipe having a flange at both ends. It is about a grounded ring.

[0002]

2. Description of the Related Art Electromagnetic flowmeters are installed and used in piping of various plants. Therefore, a stray current may be mixed from the pipe portion via the fluid, which may cause deterioration of accuracy. Therefore, conventionally, an earth ring for grounding the fluid to be measured is provided at both ends of the conduit in order to remove the stray current, and the piping is connected through the ring.

FIG. 2 is a sectional view showing an embodiment using an earth ring for a pipeline in an electromagnetic flowmeter. 1 in the figure
Numeral 0 denotes a conduit, on which the exciting coil 11 is arranged. 12 is an electrode for generating a current related to the flow velocity, 13 is a conductive shrink-fit ring for protecting the outer periphery of the end of the conduit, and 14 is a transducer.

Numeral 15 denotes a flange of a mating pipe, and the conduit 10 is fixed together with gaskets 18, 19 and an earth ring 20 by bolts 16 and 17. Reference numeral 21 denotes a housing made of a conductor fixed in contact with the shrink fit ring.
4 are electrically connected by a conductive connection fitting 25 fixed.

[Problems to be solved by the invention]

FIG. 3 is a sectional view of a main part schematically showing a bending moment generated in the conduit 10 when the conduit 10 is tightened by the bolts 16 and the nuts 17 in FIG.
That is, a surface pressure is applied to the entire end face of the conduit 10 by tightening,
The earth ring 20 is fixed to the shrink fit ring 13 with screws 24. The outer diameter of the earth ring 20 is
Since the outer diameter of the shrink fit ring 13 is substantially the same as the outer diameter of the shrink fit ring 13, the surface pressure distribution becomes larger toward the outer periphery. Therefore, in a conduit with a larger diameter at the end face than in the middle, a large tensile stress concentration occurs near the entrance of the inner diameter,
This was causing cracks.

The present invention has been made to solve the above-mentioned problems of the prior art. Even when a ceramics pipe having flanges at both ends is fixed to a mating pipe, there is no concentration of tensile stress, and cracks do not occur. It is intended to provide a grounding ring for pipes.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a ceramic conduit having a flange portion at both ends, which is sandwiched and connected between mating pipes, and a grounding fluid interposed at both ends of the conduit. In the earth ring for a pipeline, the center of at least one surface of the earth ring is formed in a convex shape, and is generated at an end of the conduit when the conduit is sandwiched between pipes and tightened by bolts. The bending moment is reduced.

[0008]

[Function] Since the center of at least one surface of the earth ring is formed in a convex shape, when a ceramics conduit having flanges at both ends is sandwiched between pipes and tightened by bolts, the end of the conduit is formed. The bending moment generated from inside to outside is reduced.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
(A) is a sectional view of a main part showing an embodiment in which the pipeline earth ring of the present invention is applied to an electromagnetic flowmeter, (b) is a perspective view of the earth ring, and (c) is a conduit 10. FIG. 4 is a cross-sectional view showing a state in which stress is generated when is fixed to a mating pipe (not shown) with bolts. In these figures, the same elements as those of the conventional example shown in FIG. Numeral 20 denotes an earth ring according to the present invention, which has a convex shape near the center of the surface facing the flange 15 (preferably, a diameter corresponding to the small diameter portion B of the conduit 10).

According to the above configuration, since the convex portion is formed on the earth ring 20, the clamping force D applied through a flange (not shown) is applied to the conduit 1 as shown in FIG.
0 is uniformly transmitted to the end face along the tube axis, resulting in a uniform stress E without a moment. In addition, the convex part of the earth ring 20 may be arranged on the conduit 10 side, or the convex part may be formed on both surfaces.

[0011]

According to the present invention, as described above in detail with the embodiment, at least one surface of the earth ring is formed in a convex shape near the center, and a ceramic conduit having flange portions at both ends is connected to the pipe. The bending moment generated at the end of the conduit when it is pinched and tightened with bolts is reduced, and the sealing area is reduced, so that the sealing surface pressure can be reduced and the stress on the ceramic conduit can be reduced. it can. As a result, cracks generated at the end of the conduit can be reduced.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment in which an earth ring for a pipeline of the present invention is used in an electromagnetic flowmeter, FIG. 1 (b) is a perspective view of the earth ring, and FIG. It is a fragmentary sectional view (c).

FIG. 2 is a cross-sectional configuration diagram showing one embodiment when a conventional earth ring for a pipeline is used for an electromagnetic flowmeter.

FIG. 3 is a cross-sectional configuration diagram of a main part schematically showing a bending moment generated in a conduit when a conventional pipeline earth ring is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ceramics conduit 13 Shrink fit ring 15 Flange 18, 19 Gasket 20 Earth ring

Claims (1)

(57) [Claims] At least one of a ceramics conduit sandwiched and connected between mating pipes and having flange portions at both ends thereof, and a grounding ring for a pipeline interposed at both ends of the conduit and grounding a fluid. Characterized in that a convex portion is formed near the center of the surface of the pipe, and a bending moment generated at an end of the pipe when the pipe is sandwiched between pipes and tightened by bolts is reduced. ring.