JP2011209243A - Electromagnetic flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic flowmeter that does not need earth rings and facilitates molding of an earth.SOLUTION: The electromagnetic flowmeter includes a measurement tube 1 which allows a measurement fluid to flow therethrough and has flanges 1a at both ends; a lining member 4 formed by a resin lining the inner surface of the measurement tube; a pair of facing detection electrodes 5 in contact with the measurement fluid at an intersection of a plane perpendicular to the tube axis of the measurement tube and the center of the inner surface of the tube wall along the tube axis of the measurement tube; and a cylindrical reinforcing member 3 fixed at multiple positions to the inner surface of the measurement tube and embedded in the lining member formed by molding, to be engaged with the lining member. The reinforcing member includes projections 3b for an earth projecting in the tube axis center direction of the measurement tube at the inner circumference of both ends. The lining member is embedded at a position to allow the projections for an earth to contact with the fluid and designed such that an earth is taken out of the measurement tube.

Description

  The present invention relates to an electromagnetic flow meter, and more particularly to an electromagnetic flow meter detector having an improved earth ring.

  As shown in FIG. 4, the measuring pipe of the conventional electromagnetic flowmeter detector is formed by lining a lining material 22 from the inner surface of the measuring pipe 21 to the middle position in the radial direction of the end face of the measuring pipe flange 21a, and along the measuring pipe flange 21a. Further, the lining flare portion 22a is pressed by an earth ring 23 screwed to the measuring tube flange 21a.

  However, in this prior art, when the diameter of the measuring tube 21 is increased, it is difficult to seal between the earth ring 23 and the lining flare portion 22a unless the earth ring 23 is thickened to sufficiently hold the lining flare 22a.

  For this reason, there is a problem that the larger the diameter is, the larger the size of the stainless steel is, and the more expensive the earth ring from both the material cost and the processing cost.

  In general, an earth ring is a generic term for a ring-shaped liquid contact electrode, a ground plate, a liquid contact electrode, and the like, and generally refers to an electrode interposed between an electromagnetic flowmeter detector and this counterpart pipe.

  In order to solve such a problem of the earth ring 23, as shown in FIG. 5, a ground electrode 28 is liquid-tightly attached to the surface of the lining material 22 near the end of the measuring tube 21, and the ground electrode 28 An electromagnetic flow meter configured to lead the lead wire 25 connected to the outer periphery of the measuring tube flange 21a through the lining material 22 and through the lining material 22 and the inner surface of the measuring tube 21. (For example, refer to Patent Document 1).

  In addition, regarding the method for forming the lining material 22 of the electromagnetic flowmeter disclosed in Patent Document 1, the lining material 22 may be peeled off from the measurement tube 21 when the inside of the measurement tube 21 falls below atmospheric pressure. A technique for improving a method of forming a reinforcing material embedded in the inside is disclosed (for example, see Patent Document 2).

Japanese Patent Publication No. 7-89069 Japanese Patent Publication No. 3-124

  In the case of the structure in which the grounding electrode disclosed in Patent Document 1 is used as the installation potential, the conventional grounding ring can be eliminated, but the grounding electrode that penetrates the lining material and the lead connected to this electrode Because it is a structure that draws the wire between the measurement and the lining material along the measurement tube, it not only requires a new grounding member and its molding process, but also makes it difficult to mold the grounding electrode part that requires sealing There is a problem.

  In addition, since the liquid contact surface of the ground electrode has a small liquid contact area, there is a problem that the ground resistance increases as the electrical conductivity decreases, and the performance of the electromagnetic flowmeter as a ground for the detection electrode deteriorates.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electromagnetic flowmeter that does not require a grounding ring and can easily form the grounding.

  In order to achieve the above object, an electromagnetic flowmeter of the present invention comprises a measuring tube for flowing a fluid to be measured and having flanges at both ends thereof, a lining material lined with resin on the inner surface of the measuring tube, and the measuring tube A pair of detection electrodes provided in contact with and in contact with the fluid to be measured at a position where a plane perpendicular to the tube axis intersects with a tube wall inner surface at the center in the tube axis direction of the measurement tube; Cylindrical reinforcing material that is fixed to the inner surface of the measuring tube at a plurality of locations and embedded in the lining material to be molded and engages the lining material, and the reinforcing material, It is provided with a grounding convex portion protruding in the tube axis center direction of the measuring tube, and the lining material is embedded in a position where the grounding convex portion can come into contact with liquid, and the ground is taken out from the measuring tube. Features.

  As described above, according to the present invention, it is possible to provide an electromagnetic flow meter that does not require an earth ring and can easily form an earth electrode.

Explanatory drawing of the earth | ground structure of Example 1 of the electromagnetic flowmeter detector of this invention. The modification of the electrode part for earth | grounding of Example 1 of the electromagnetic flowmeter detector of this invention. Explanatory drawing of the electrode part for earth | ground of Example 2 of the electromagnetic flowmeter detector of this invention. Conventional electromagnetic flowmeter detector with earth ring. A conventional electromagnetic flowmeter detector with a grounding electrode.

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

  FIG. 1 shows the structure of the electromagnetic flowmeter detector according to the first embodiment of the present invention. The electromagnetic flowmeter detector of the present invention flows a fluid to be measured and has a measuring tube 1 having flanges 1a at both ends thereof, a lining material 4 in which resin is lined on the inner surface of the measuring tube 1, and a tube axis of the measuring tube 1 A pair of detection electrodes 5 provided in contact with and in contact with the fluid to be measured at a position where the plane perpendicular to the tube intersects with the inner wall surface of the tube tube in the center of the tube axis direction of the measurement tube 1. And a cylindrical reinforcing member 3 that is fixed to the inner surface at a plurality of locations and is embedded in a lining material 4 to be molded to lock the lining material 4.

  Furthermore, an excitation unit that applies a magnetic field in a direction orthogonal to the detection electrode and the tube axis direction from the outer tube wall of the measurement tube 1 (not shown), and a detection circuit unit that amplifies the electromotive force detected between the detection electrodes 5 are provided. .

  As shown in the upper part of the cross-sectional view before the lining in FIG. 1 and the details of FIG. 1A, the cylindrical reinforcing member 3 is composed of a measuring tube fixing portion 3a for fixing a plurality of locations on the inner wall surface of the measuring tube 1 and a melt reinforcing material 3. On the inner periphery of both ends, a grounding convex portion 3b projecting toward the center of the tube axis of the measuring tube 1 is provided.

  Then, as shown in detail in the lower part of the cross-sectional view and the B part in FIG. 1, the lining material 4 is embedded in a position where the ground convex part 3 b can come into contact with the liquid, and the ground is taken out from the measuring tube 1. .

  Further, the reinforcing material 3 has a liquid contact surface portion of the grounding convex portion 3b as the entire inner circumference, and has a liquid contact area equivalent to that of a conventional earth ring.

  The material of each part is, for example, the measurement tube 1, the reinforcing material 3, and the detection electrode 5 made of non-magnetic material having good corrosion resistance such as SUS, and the lining material 4 is made of rubber or resin such as Teflon (registered trademark). In many cases.

  According to the electromagnetic flowmeter detector having such a configuration, the measuring tube fixing for fixing the plurality of locations while the inner peripheral surface of the reinforcing member 3 is in contact with the fluid to be measured on the liquid contact surface portion of the ground convex portion 3b. Since the portion 3a is electrically connected to the measuring tube 1, it is only necessary to provide the reinforcing member 3 with the grounding convex portion 3b, so that the conventional grounding ring is not required, and the conventional grounding performance is not deteriorated. Thus, it is possible to take out the ground from an arbitrary position during the measurement 1 without changing the molding process of the lining.

  Also, as shown in FIG. 2, by applying a corrosion-resistant metal such as titanium or ceramics to the liquid contact portion of the grounding convex portion 3b, adaptation is possible even when the fluid to be measured is highly corrosive.

  A second embodiment of the present invention will be described with reference to FIG. 3, the same parts as those of the electromagnetic flow meter shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  Example 2 shown in FIG. 3 differs from Example 1 shown in FIG. 1 in that Example 2 is replaced with a reinforcing material 3 divided into two parts instead of the cylindrical reinforcing material 3 of Example 1. It is in.

  In this case, the reinforcing member 3 is formed into a plurality of divided cylindrical shapes, and the cross-sectional shape of the liquid contact surface portion of the ground convex portion 3b is in the tube axis direction with respect to the pair of detection electrode axis planes x1-x2. The shape is plane-symmetric at each point.

  By forming such a wetted surface portion on the grounding convex portion 3b of the reinforcing member 3, the detection electrode 5 is provided at a position symmetrical to the measurement tube 1 serving as the ground reference potential, so that the internal impedance for the detection signal is increased. Has the same effect. Therefore, an increase in common mode noise of the electromagnetic flow meter can be prevented.

  The present invention is not limited to the embodiments described above, and the number and shape of the reinforcing material may be appropriately changed in accordance with the molding process of the lining material, and within the scope not departing from the gist of the present invention. Various modifications can be made.

1, 21 Measuring tube 1a, 21a Flange 3 Reinforcing material 3a Measuring tube fixing part 3b Protruding part for grounding 4, 22 Lining material 23 Grounding ring 25 Lead wire 28 Grounding electrode

Claims (4)

A measurement tube that flows the fluid to be measured and has flanges at both ends thereof; and
A lining material lined with resin on the inner surface of the measuring tube;
A pair of detection electrodes provided in contact with and in contact with the fluid to be measured at a position where the plane perpendicular to the tube axis of the measurement tube intersects the inner wall surface of the tube tube in the tube axis direction. When,
A cylindrical reinforcing material that is fixed to the inner surface of the measuring tube at a plurality of locations and embedded in the lining material to be molded and that locks the lining material,
The reinforcing member includes a grounding convex portion projecting toward the center of the tube axis of the measuring tube at the inner periphery of both ends, and the lining material is embedded in a position where the grounding convex portion can come into contact with the liquid, An electromagnetic flow meter characterized in that the ground is taken out from the measuring tube.   The electromagnetic flowmeter according to claim 1, wherein the liquid contact surface portion of the ground convex portion is made of a corrosion-resistant metal.   The electromagnetic flowmeter according to claim 1, wherein the liquid contact surface portion of the grounding convex portion is the entire inner circumference.   The reinforcing material is formed into a plurality of divided cylindrical shapes, and the cross-sectional shape of the liquid contact surface portion of the grounding convex portion is symmetrical at each point in the tube axis direction with respect to the pair of detection electrode axis planes. The electromagnetic flow meter according to claim 1, which is shaped.

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