JPS63145918A - Detector for electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To achieve a lower cost of an electromagnetic flowmeter detector, by keeping an earth object in contact with a liquid to make a liquid in a measuring tube conductive to the measuring tube while the measuring tube is grounded. CONSTITUTION:An earth object 6 comprising a conducting piece is provided at the end of an electrically insulating lining 3a of a measuring tube 2 with one end thereof exposed from the liquid contact surface of the lining 3a and buried securely into a lining addition layer 3b together with a lead conductor 7 of the measuring tube connected to the other end of the object 6. With the liquid contact of the object 6, a fluid in the measuring tube 2 is made conductive to the measuring tube 2 to allow the grounding of the measuring tube 2 thereby enabling a reduction in the cost eliminating any metal earth ring.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to electromagnetic flowmeter detectors, and more particularly to the grounding of measuring tubes provided with electrically insulating running therein.

(Prior Art) In an electromagnetic flowmeter detector having a measuring tube with an electrically insulating lining, the determination of the zero point of the measuring circuit,
Removal of noise generated within the detector.

In order to eliminate noise and construct a differential circuit for high-precision measurements, the measuring tube is grounded by attaching electrically sensitive earth rings to both end faces of the measuring tube.

A recess is formed in the ground ring to escape the end part (flare part) of the running that overlaps the flange surface of the measurement tube, but in order to carve out the recess in a thin flat ring, it is necessary to
Since the discrepancy occurs, the back side must also be cut to remove the discrepancy, and if the back side is cut, a small discrepancy will occur again on the front side, so it is necessary to perform finish cutting again. In this way, the manufacturing cost of the earth ring is high, and since it comes into contact with liquid, highly corrosion-resistant materials such as Ta, Ti, Hastelloy C, 5O3316, etc. are used, so the material cost is also high.
As a result, the ground ring becomes very expensive, and therefore, users of electromagnetic flowmeters desire an inexpensive ground ring.

As a countermeasure to this problem, a technique has been proposed, for example, as disclosed in Japanese Utility Model Application Publication No. 58-186429, in which carbon powder is mixed into the end of the insulating lining to replace it with a metal ground ring. However, carbon powder does not exhibit conductivity unless its content (volume) in the resin is about 15% or more.

When the carbon content is around 15%, the electrical resistance is several tens of Ω.
/l, making it useless.If you try to increase the carbon content and reduce the electrical resistance, the permeability of the liquid will increase, and the liquid will pass through to the measuring tube. If the liquid is corrosive, it may corrode the measuring tube and lead to an accident.

(Problems to be Solved by the Invention) As mentioned above, the conventional grounding ring requires a lot of time and effort to process, and the main material is expensive, which is a bottleneck in reducing the cost of electromagnetic flowmeter detectors.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electromagnetic flowmeter detector which is equipped with a measuring tube grounding means in place of a ground ring and which can reduce costs.

[Structure of the invention]

(Means for Solving the Problems) The electromagnetic flowmeter detector of the present invention has a grounding object made of a small conductive piece at the end of the electrically insulating lining of the measuring tube, with one end of the grounding object extending from the liquid contact surface of the lining. A structure in which the lead conductor to the measuring tube is exposed and connected to the other end is buried by an additional layer of lining (first invention), or the end of the electrically insulating lining of the measuring tube is connected from its wetted surface to The structure is such that a grounding object made of an elastic organic material in which conductive powder is dispersed at a volume content of about 30% is disposed at the terminal (second invention).

(Function) In the electromagnetic flowmeter detector of the present invention, a metal ground ring is not required because the grounding object comes in contact with the liquid and performs the function of grounding the measuring tube by establishing continuity between the fluid in the measuring tube and the measuring tube. This makes it possible to reduce the cost of electromagnetic flowmeter detectors. In addition, the grounding object is either a thin piece embedded in the lining layer, or it is an elastic organic material itself that has been made into a conductor by dispersing conductive powder.
It conforms well to the contacting backing, and its sealing function is comparable to that of the original lining.

(Example) Hereinafter, the present invention will be described in detail based on the example shown in the drawings. Fig. 1 shows an electromagnetic flowmeter detector according to an embodiment of the first invention of the present application.This electromagnetic flowmeter detector is of a flange connection type, and the measuring tube (■) has flanges (■) at both ends, and is electrically insulated. A gender lining (3a) is provided. (A) is the terminal tube, and ■ is the case that covers the magnetic field generation part.

At the end (on one or both sides) of the electrically insulating lining (3a), a grounding object 0 consisting of a small piece of a conductive thin plate has one end exposed from the wetted surface of the lining (3a), and the exposed part is connected to the measuring tube. A plurality of lead conductors (71 (in this implementation In the example, it is buried and fixed together with the ground M) by the additional lining layer (3b).The lead conductor ■ of each ground object ■ is connected to the additional lining layer (3b).
3b) is connected in series inside the lining (3a)
The ground wire (■) coming out from the terminal of is connected to a terminal provided on the outer peripheral surface of the flange (■) of the measuring tube (■).

In the electromagnetic flowmeter detector of the embodiment of the first invention of the present application configured as described above, the ground object 0 comes into contact with the liquid and connects the fluid in the measuring tube with the measuring tube ■, thereby grounding the measuring tube. This function eliminates the need for a metal ground ring, making it possible to reduce the cost of the electromagnetic flowmeter detector. Furthermore, since the grounding object is a thin plate and has elasticity, its sealing function is comparable to that of the original lining.

Here, the process of embedding the ground object 0 and the lead conductor (2) is shown in FIGS. 3(a) and (b) and FIGS. 4(a) and (b).

This will be explained with reference to FIGS. 5(a) and 5(b). In this example, the material of the lining (3a) and the additional lining layer (3b) is chloroprene rubber, and the grounding object (0 is a thin plate of 5tlS316 with a thickness of ``law'' with a plurality of holes drilled on its surface). It was sandblasted as an adhesive treatment, and the four leads are shown in Figure 5 (a).
As shown in Figure 2, when the insulating liquid [(7a) is used as an airtight sheath and the fluid in the measurement tube passes between the ground object 0 and the lining (3a) or between the lead conductor ■ and the lining (3a), The explanation will be given by taking as an example a case in which the belt is tightened with a tightening band (7b) in consideration of the above. In addition, if the ground object 0 and the lining can be completely bonded, use an insulating coating (7a).

There is no need to use the tightening band (7b).

First, the inner surface of the measuring tube ■ was roughened by sandblasting.
An unvulcanized chloroprene rubber sheet (hereinafter referred to as an unvulcanized rubber sheet) is glued with rubber glue to create the state shown in Figure 3 (b), and then the ground object (Q and lead conductor
) to the end face of the lining (3a) with rubber glue, and place an unvulcanized rubber sheet of the same thickness as the ground object 0 around the ground object 0 and into the hole (6a) of the ground object, and then attach the lining (3a) ) to make the end surface smooth as shown in Figure 4(b) 6 Next, apply an additional lining layer made of unvulcanized rubber sheet with rubber glue, and attach the external lead conductor. Apply rubber glue to (7a) and attach an insulating cover (7a) made of unvulcanized rubber sheath. Rub the entire adhesive surface with a roller to expel any air bubbles caught in the adhesive surface. Place this in a pressurized can and apply a weight of approximately 4 kg/d. A pressure of 150° C. was applied and vulcanization was performed at 150° C. for 3 hours to complete the state shown in FIGS. 5(a) and 5(b).

The embodiment shown in Fig. 1 is a case of a flange-connected electromagnetic flowmeter detector, but a sandwich-type electromagnetic flowmeter detector shown as another embodiment in Fig. 2 can be similarly applied by the above-mentioned process. It can be made by In Figure 2, the first
The same parts as those in the figure are given the same reference numerals, and the other parts (c) are the flanges of the mating pipe (10), and ■ are the tightening bolts and nuts.

Fig. 6 shows still another embodiment, in which a ring-plate-shaped grounding material made by embedding the grounding object 0 and the lead conductor (2) in rubber or plastic is placed at the end of the lining (3a) of the measuring tube (2). The lining body (11) is attached by adhesive or the like.

Furthermore, FIG. 7 is FIG. 4(a) of the above-mentioned process.

In the step (b), a large number of ground objects (2) are arranged in the circumferential direction and connected by conductive wires (7c).

Further, the shape of the ground object is preferably a simple shape, which is advantageous for degassing during bonding, and the shape as shown in FIGS. 8(a) and 8(b) is preferable. However, the adhesion between the grounding object and the lining is determined by the adhesive substance and type of adhesive, so in order to prevent the grounding object from falling into the fluid side even if the adhesion is incomplete, grounding objects of various shapes are required. becomes. Figures 8(c) to 8(f) are examples of shapes that are effective for preventing falling off, and Figure 8(Q) has a concave side edge to prevent slipping.
FIG. 8(d) shows the tapered surface of the side edge and the coupling of the lining and the additional layer of lining through a plurality of holes (6a) to prevent slippage, and FIG. 8(e) shows the tapered surface of the side edge. The notch in the center has a narrow opening that prevents it from shifting. FIG. 8(f) is an example of a grounding object (2) in which conductive wires are woven into a lattice shape, and the lining and the additional lining layer are bonded to each other through the holes of each lattice to prevent displacement. In addition, in FIGS. 8(a) to 8(f), the lower edge shown is the liquid contact surface exposed from the lining surface.

In addition to the grounding object 0 having a flat plate shape, the part exposed from the lining (3a) is placed along the surface of the lining (3a) as shown in FIG. 9(a) in order to increase the area in contact with the liquid. It may be bent at the same time, the bent end may be bitten into the lining (3a) as shown in FIG. 9(b), or it may be rolled into a U-shape as shown in FIG. 9(c).

Next, an embodiment of the invention of the cylinder 2 of the present invention is shown in FIG. A grounding object (16) is placed at the end along the flange (1) of the electrically insulating lining (3a) applied to the measuring tube (2) of the electromagnetic flowmeter detector, from the liquid contact surface to the terminal. This grounding object (16) is made by kneading about 30% of carbon powder as a conductive powder into an elastic organic material 1, such as unvulcanized chloroprene rubber, and forming it into a sheet shape with a calender roll. It is attached to the lining (3a) with rubber glue and vulcanized under pressure, and its electrical resistance can be several hundred ohms/mouth. A lead conductor (17) is connected to the radially outer peripheral end of the earth object (16) and is coated with an insulation coating (17a), and the lead conductor (17) is attached to the flange (not shown) of the measurement tube (■). connected to the terminal.

In the electromagnetic flowmeter detector according to the embodiment of the invention of Application 2 constructed as described above, the grounding object (16) comes into contact with the liquid and connects the fluid in the measuring tube with the measuring tube (2). Since the metal ground ring is not required, the cost of the electromagnetic flowmeter detector can be reduced. In addition, since the grounding object (16) is made of an elastic organic material itself that has been made into a conductor by dispersing conductive powder, it has good compatibility with the backing that comes into contact with it, and its sealing function is comparable to that of the original lining. . Furthermore, by mixing and dispersing about 30% of the conductive powder, the electrical resistance value was able to be several hundreds of ohms/am, so the conductive properties were equivalent to those using a metal earth ring.

In the embodiment shown in FIG. 10, the grounding objects (16) are formed in a continuous ring shape in the circumferential direction, but as shown in FIG. , each earthing object (16) may be connected by a conducting wire.

In addition, the grounding object (16) uses plastic instead of chloroprene rubber, and uses carbon powder or Ag.
It may also be made by dispersing metal powder such as Ni or 5US316.

〔Effect of the invention〕

As detailed above, according to the first invention and the second invention of the present application, in the electromagnetic flowmeter detector, a grounding object made of a small conductive piece is attached to one end of the electrically insulating lining of the measuring tube. The end of the electrically insulating lining of the measuring tube is placed either embedded in an additional layer of lining with the lead conductor to the measuring tube exposed from the wetted side of the lining and connected to the other end of the measuring tube on its wetted side. By placing a grounding object made of elastic organic material in which conductive powder is dispersed at a volume content of about 30% over the terminal, and connecting the lead conductor from the grounding object to the measuring tube, the grounding object can be Since it functions to ground the measuring tube by contacting the liquid and bringing the fluid in the measuring tube into conduction with the measuring tube, a metal grounding ring is no longer required, making it possible to reduce the cost of the electromagnetic flowmeter detector. In addition, because the grounding object is a thin piece buried in the lining layer, or it is an elastic organic material itself that has been made into a conductor by dispersing conductive powder, it is compatible with the backing that comes into contact with it, and the sealing function is also original. There is no inferiority compared to the case of conventional lining.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway diagram showing an electromagnetic flowmeter detector according to an embodiment of the invention of Application 1, and Fig. 2 shows an electromagnetic flowmeter detector of another embodiment of the invention of Application 1. A partially cutaway diagram,
Figures 3 (a) and (b), Figures 4 (a) and (b), and Figure 5 (a) and (b) are explanatory diagrams showing the process of burying the earth object and lead conductor, and Figure 6. is a diagram showing the vicinity of a grounding object in another embodiment of the invention of Application 1, FIG. 7 is a diagram showing the arrangement of a grounding object in another embodiment of the invention of Application 1,
a). (b), (c), (d), (8), and (f) are diagrams showing various embodiments of the earthing object of the invention of the present application 1, respectively;
FIGS. 9(a), (b), and (c) are diagrams showing various embodiments of the wetted part of the grounding object of the invention of the present application 1, respectively, and an embodiment of the invention of the 1st Azuchi application 2. Figure 11 is a diagram showing the area around the ground object of the electromagnetic flow meter detector as an example.
FIG. 3 is a diagram showing the vicinity of a grounding object of an electromagnetic flowmeter detector according to another embodiment of the invention. 1...Flange 2...Measuring tube 3a...
Electrical insulating lining 3b...additional lining layer 6...earth object 6a
...hole 7...lead conductor 7a...
・Insulating coating 7b...Tightening band 7c...
Conductor wire 11...Earth lining body 16...Earth object 17...Lead conductor 1
7a...Insulating coating

Claims (2)

[Claims] (1) In an electromagnetic flowmeter detector having a measuring tube with an electrically insulating lining, a grounding object made of a small conductive piece is attached to the end of the lining with one end exposed from the lining's liquid contact surface and connected to the other end. An electromagnetic flowmeter detector characterized in that the lead conductor is embedded in an additional layer of lining. (2) In an electromagnetic flowmeter detector having a measuring tube with an electrically insulating lining, conductive powder is applied to the end of the lining from the liquid contact surface to the end at a volume content of 30%.
1. An electromagnetic flowmeter detector characterized in that a grounding object is disposed at the non-liquid-wetted end of the elastic organic material, and a lead conductor is connected to the non-liquid end.