JPH0882539A - Detector of electromagnetic flowmeter - Google Patents

Abstract

PURPOSE: To prevent the state such as breakage caused by the excessive concentration of stress and to achieve the improvement of airtightness, the light weight of the entire body and the low cost. CONSTITUTION: Double-structured flange parts 20, in each of which a pipe connecting flange 21 and a coil-chamber side plate 22 are formed as a unitary body through a measuring-pipe reinforcing collar 23, are provided at both end parts of the measuring pipe 1. The thickness of the measuring-pipe reinforcing collar 23 is formed as 0.01D-0.6D, where D is the nominal diameter of the detector of an electromagnetic flowmeter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flowmeter detector having a pipe connecting flange.

[0002]

2. Description of the Related Art As an electromagnetic flowmeter detector, for example, there is a technique described in Japanese Patent Application No. 61-224847.
FIG. 7 is a structural diagram of such an electromagnetic flow meter detector. The measurement pipe 1 is a strength base member that bears a tensile or compression force based on the expansion and contraction of the pipe due to the pressure and temperature changes of the fluid to be measured, and is a rigid structure member having a required inner diameter, wall thickness, and length to withstand it. It is formed of a magnetic metal, for example, a stainless steel pipe.

A wiring lead-out pipe 2 is welded concentrically with the diameter axis at the center of the measuring pipe 1 in the longitudinal direction. The wiring lead-out pipe 2 is made of a non-magnetic metal such as stainless steel and has a required diameter and length.

Separately, a thin metal plate, for example, a thin steel plate, is rolled to form an annular continuous coil, which is cut one turn at a time and the terminals are welded to each other. The side plate 3 is manufactured.

Further, the pipe connecting flange 4 is of a required standard based on the pressure of the fluid to be measured, has a shape with a hub 5 having increased rigidity, and has predetermined bolt holes formed therein. The material for the pipe connecting flange 4 may be a non-magnetic metal or a magnetic metal.

The coil chamber side plates 3 are divided into two pieces in the longitudinal center of the measuring tube 1 and externally fitted and welded to the measuring tube 1 at required intervals. Further, the pipe connecting flanges 4 are provided at both ends of the measuring tube 1. It is externally fitted and welded to the part.

Separately, the terminal box mounting base 6 is concentrically attached with a pipe having an inner diameter, which is made of a magnetic metal, such as steel, and is fitted on the lower surface of a disk having a required diameter with the wiring lead-out pipe 2 with a gap.
In addition, the disk is formed in a shape in which a hole for fitting the wiring lead-out pipe 2 is formed.

The terminal box mounting base 6 is welded to the wiring lead-out pipe 2 with the holes of the disk aligned. The measurement tube assembly is formed as described above.

A lining 7 is applied to the inner surface of the measuring pipe 1 of the measuring pipe assembly and the contact surface of the pipe connecting flange 4 with the lining flare portion. In this lining 7, the contact surface between the inner surface of the measuring pipe 1 and the lining flare portion of the pipe connecting flange 4 is roughened by sandblasting, and the raw rubber is adhered with a rubber paste. It is placed in a live steam can and vulcanized at high temperature before it is constructed.

With respect to the measuring tube assembly with the lining applied, the electrodes 8 are respectively placed on the symmetrical tube walls of the measuring tube 1 by arranging them on the diameter axis of the measuring tube 1 which is orthogonal to the axis of the pipe 2 for leading out the wiring. Installed.

A pair of saddle type coils 9 are attached to the outer surface of the measuring tube 1 symmetrically with respect to a plane including the axis of the electrode 8 and the tube axis of the measuring tube 1. The saddle type coil 9 is fixed by a stud, a hand and a nut provided by welding at a required position of the measuring tube 1.

Each lead wire of the electrode 8 and the saddle type coil 9 is inserted into the pipe 2 through a window hole provided in the wiring lead-out pipe 2, and is led out to the outside through the pipe 2 to form a terminal. A terminal box is attached to the box mounting base 6, and each drawn out lead wire is connected to a predetermined terminal.

On the other hand, the pair of coil chamber outer peripheral plates 10 is a pair of coil chamber side plates 3 welded to the measuring pipe 1 and each of which is a cylinder having a length and a diameter so that the ends in the pipe axis direction are externally fitted. A magnetic metal, for example, a thin steel plate, which is divided into two parts on a plane including the axis and the axis of the wiring derivation pipe 2 and which is further provided with a semicircular cutout for engaging with the pipe of the terminal box mounting base 6. There is.

The pair of coil chamber outer peripheral plates 10 are attached to the measuring tube assembly in which electrical parts are attached and wiring is completed, and the coil chamber side plate 3 and the terminal box attachment base 6 are in contact with the pipes. The contact portion and the joint end of the coil chamber outer peripheral plate 10 are welded to each other.

Particularly, the structure of the pipe connecting flanges 4 at both ends of the measuring pipe 1 will be described. As shown in FIG. 8, a pair of coil chamber side plates 3 are externally welded to the measuring pipe 1. .

A pair of pipe connecting flanges 4 are welded to both ends of the measuring pipe 1, and a lining 7 is applied to the measuring pipe assembly. The electrode 8 and the exciting coil 9 are assembled to the measuring tube assembly having the lining.

A pair of coil chamber side plates 3 are attached with a pair of coil chamber outer peripheral plates 10 formed of a magnetic metal thin plate in a shape in which a cylinder is divided into two parts by a plane including its axis and a tube axial direction end is externally fitted. ing.

The contact portion with the measuring tube assembly and the joint ends of the coil chamber outer peripheral plate 10 are welded to each other. With such a structure of the electromagnetic flowmeter detector, the measuring tube 1 itself is a rigid structural member made of a non-magnetic metal having a required strength to bear the stress from the fluid to be measured and the stress at the time of pipe connection, and the flexible structure. Coil chamber side plate 3 and coil chamber outer peripheral plate 1
0, the exciting coil 9, and the magnetic circuit portion formed by the measuring tube 1 are insulated from the pipe connecting flange 4.

For this reason, no stress is exerted on the magnetic circuit portion during pipe connection and no adverse effect occurs. Further, by selecting the pipe connecting flange 4 in accordance with the mating pipe standard, other configurations can be obtained. Parts can be shared, which is advantageous in product preparation.

[0020]

However, in the case of the electromagnetic flowmeter detector having a welded structure as described above, the wall thickness becomes thicker in order to make the measuring pipe 1 bear the required strength, and the coil chamber side plate 3 and the pipes. A space for welding work is required between the connection flange 4 and the welding work space, which increases the weight due to the fact that the welding work space increases the overall length.

At the same time, there is a concern that airtight leakage may occur due to defective welding at the welded portion of the coil chamber side plate 3 and the welded portion of the coil chamber outer peripheral plate 10. Further, when the pipe connecting flanges 4 at both ends of the measuring pipe 1 are connected to the pipe side flanges, the pipe connecting flanges 4 are connected by an external force at this time.
Also, excessive stress is concentrated on the end portion of the measuring tube 1, and if this stress rises, there is a problem in strength such that it may break.

In particular, such concentration of stress at both ends of the measuring pipe 1 is remarkable at the welded portions of the pipe connecting flange 4 and the measuring pipe 1, and a large bending moment is generated at these joints to alleviate this. Measures are needed for this.

Therefore, in order to secure the strength at the welded portion between the pipe connecting flange 4 and the measuring pipe 1, the pipe connecting flange 4 and the measuring pipe 1 must be formed thick so as to have sufficient required strength. .

With such a thick structure, it is difficult to avoid stress concentration on the welded portion between the pipe connecting flange 4 and the measuring pipe 1, and in order to prevent this, the thickness of each part should be reduced. It must be made thicker, which results in an increase in the weight of the electromagnetic flowmeter detector and an increase in cost.

Further, in Japanese Patent Application No. 61-224847, as shown in FIG. 9, a flange 11 for connecting a pipe with a bolt hole is provided.
The structure in which the coil chamber side plate 12 and the coil chamber side plate 12 are integrated is described, and such a structure is applied when it is allowed to slightly lower the measurement accuracy as compared with the structure shown in FIG. Is.

However, with such a structure,
The pipe connecting flange 4 and the measuring pipe 1 can be formed thick so as to have sufficient required strength, but the thickness and the length thereof are not specified, and the pipe connecting flange 4 and the measuring pipe 1 can be reliably measured. It is difficult to say that the stress concentration on the welded portion with the pipe 1 is avoided.

Therefore, an object of the present invention is to provide an electromagnetic flowmeter detector capable of preventing a situation such as destruction due to excessive stress concentration, improving airtightness, and achieving overall weight reduction and cost reduction. And

[0028]

According to a first aspect of the present invention, in an electromagnetic flowmeter detector in which an exciting coil is installed on an outer peripheral portion of a measuring pipe, a pipe connecting flange and an exciting coil are housed at both ends of the measuring pipe. In order to do this, each side of the coil chamber is provided with a double structure flange part that is integrally formed through a measuring tube reinforcing collar, and the thickness of the measuring tube reinforcing collar is expressed as the nominal diameter of the electromagnetic flowmeter detector as D. It is an electromagnetic flowmeter detector which is formed to have a thickness of 0.01 D to 0.6 D to achieve the above object.

According to the second aspect, in the electromagnetic flowmeter detector in which the exciting coil is installed on the outer peripheral portion of the measuring pipe, the coil for accommodating the flange for connecting the pipe and the exciting coil to both ends of the measuring pipe. When double-structured flanges are integrally formed by integrating the chamber side plate with the measuring tube reinforcing collar, and the thickness of the measuring tube reinforcing collar is expressed as the nominal diameter of the electromagnetic flowmeter detector as D. It is an electromagnetic flowmeter detector which is formed to have a thickness of 0.01 D to 0.6 D to achieve the above object. According to the third aspect, the double structure flange portion is formed of a functionally graded material having a non-magnetic material on the inner surface side and carbon steel on the outer peripheral side.

[0030]

According to the first aspect of the present invention, the double-structured flange portion is integrally formed with the pipe connection flange and the coil chamber side plate for accommodating the exciting coil on both ends of the measuring pipe through the measuring pipe reinforcing collar. And the thickness of the measuring tube reinforcing collar is 0 when the nominal diameter of the electromagnetic flowmeter detector is represented by D.
By forming it from 01D to 0.6D, the double-structured flange portion can reinforce both ends of the measuring pipe on which mechanical stress acts, thin the measuring pipe to reduce the weight, and It is possible to reduce the number of welding points between the pipe connection flange and the coil chamber side plate, and to reduce airtightness and work costs.

According to the second aspect of the present invention, the double-structured flange portion in which the pipe connection flange and the coil chamber side plate for accommodating the exciting coil are integrated via the measuring pipe reinforcing collar is provided at both ends of the measuring pipe. Even if they are integrally formed and the thickness of the measuring tube reinforcing collar is set to 0.01D to 0.6D, the both ends of the measuring tube on which mechanical stress acts similarly to the above can be reinforced, It is possible to reduce the thickness by reducing the thickness and reduce the number of welding points between the pipe connection flange and the coil chamber side plate, thereby reducing airtightness and working cost.

According to the third aspect, even if the double-structured flange portion is formed of a functionally graded material having an inner surface side made of a non-magnetic material and an outer circumference side made of carbon steel, the same effect as described above can be obtained.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. The same parts as those in FIG. 7 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a configuration diagram showing a portion of a pipe connection flange of an electromagnetic flow meter detector.

Here, the background of realizing the structure of this electromagnetic flowmeter detector will be explained. The bending moment M from the pipe connecting flange to the end face of the measuring pipe 1 as shown in FIG.
When o acts, the bending moment Mx of the measuring tube 1 in the X-axis direction decreases as it moves away from the end surface of the measuring tube 1 as shown in FIG. It is known that the bending moment Mo from the flange ceases to work.

2 and 3, Mo is an action moment, Mx is a generated moment at the position x, β is a constant determined by the diameter and wall thickness of the measuring tube 1, and β ⁴ = 3 × (1 −ν ² ) · (1 / a ² · h ² ) ... (1).

Here, ν is the Poisson's ratio, a is the radius of the measuring tube 1, and h is the wall thickness of the measuring tube 1. From this, the thickness of the measuring pipe 1 having the required strength for bearing the stress at the time of pipe connection is required within the range in which the bending moment Mx acts, and the thickness of the measuring pipe 1 near the center beyond this range is It suffices to provide a thickness that bears the stress from the fluid pressure.

Therefore, in order to reduce the weight of the measuring tube 1 and to have a structure having a required strength, it is realized by forming the measuring tube 1 near the end face to be thick and near the center to be thin. Is.

The structure of the electromagnetic flowmeter detector shown in FIG. 1 will be described. The measuring tube 1 is a strength matrix that bears a tensile or compression force based on the expansion and contraction of the pipe due to the pressure and temperature changes of the fluid to be measured, and It is a rigid structural member having a required inner diameter, wall thickness, and length that can withstand, and is formed of a pipe of magnetic metal, such as stainless steel.

An insulating lining 7 made of Teflon, rubber or the like is formed over the entire inner surface of the measuring tube 1 including the outer surface of the pipe connecting flange 21. A pair of electrodes 8 having opposing connecting ends are inserted on the diametrical axis line at the center in the longitudinal direction of the measuring tube 1 provided with the lining 7, and the axis line of the electrode 8 and the tube axis of the measuring tube 1 are included. A pair of exciting coils 9 for symmetrically applying a magnetic field to the plane are fixed to the outer peripheral portion of the measuring tube 1, respectively.

The electromotive force generated in the fluid to be measured having conductivity is taken out by the electrode 8 and the flow rate of the fluid to be measured flowing in the measuring tube 1 is measured. At both ends of this measuring pipe 1, a pair of double structure flange portions 2
0 is produced by machining and is externally fitted and welded.

The double-structured flange portion 20 includes a pipe connection flange 21 of a required standard based on the pressure of the fluid to be measured and a thin plate ring-shaped coil chamber side plate 22 for accommodating the exciting coil 9, and a measuring tube reinforcing collar. It is formed integrally via 23. The measuring tube reinforcing collar 23 is provided to increase the rigidity of the measuring tube 1.

The material of the double structure flange portion 20 may be a non-magnetic metal or a magnetic metal. The above measuring tube reinforcing collar 23
The thickness is defined as 0.01D to 0.6D when the nominal diameter of the electromagnetic flowmeter detector is represented as D.

The thickness of the measuring tube reinforcing collar 23 is 0.01D.
0.6D is a finite element method (FEM: finite element method analysis software I-DEAS; Structural Dynamics Research Corpo)
ration).

That is, in the electromagnetic flow meter, the pipe 1 and the coil chamber side plate 22 and the pipe connecting flange 21 which are mechanical stresses at the time of pipe connection or due to fluid pressure are applied.
Is modeled with the double structure flange portion 20 and the like integrally formed with the measuring pipe reinforcing collar 23, and analyzed by strength calculation by the finite element method, and the thickness of the measuring pipe reinforcing collar 23 is calculated based on the calculation result. It is formed to 0.01D to 0.6D.

Here, in the strength analysis calculation model by the finite element method, the pipe connection flange 21 is formed of SS400, the measurement pipe 1 is formed of SUS304, and the design pressure is JIS 10
k, by calculating the external force condition acting on the measuring pipe 1 and the pipe connecting flange 21, etc., the force P due to the fluid pressure acting on the inner surface of the measuring pipe 1, the tightening force F of the pipe bolt in the pipe axis direction, etc. Strength analysis calculation is performed. In addition, S
The maximum allowable stress of S400 and SUS304 is 101 MPa
(10.3 kgf / cm ² ).

In the case of the electromagnetic flowmeter detector having such a structure, it is necessary to select an appropriate thickness of the measuring pipe reinforcing collar 23 in order to disperse the stress concentrated at the root of the pipe connecting flange 21. It will have sufficient strength.

Further, the weight reduction and the cost reduction can be realized by forming a commercially available steel material and making each member as thin as possible. That is, to explain a comparison with the conventional electromagnetic flowmeter detector shown in FIG. 7, since the pipe connecting flange 4 is directly welded and fixed to the measuring pipe 1 in the conventional structure,
Doing strength analysis by the finite element method for this call bore 50A, to 101MPa (10.3kgf / cm ²⁾ (the maximum stress value σmax material) up to the base of the pipe connection flange 4, as shown in FIG. 4 It was confirmed that the reaching stress is locally concentrated and may cause destruction.

Further, as a result of various studies based on the strength calculation by the finite element method, the root surface of the pipe connection flange 21 is set to R5 or more, and the measuring pipe reinforcing collar 23 is connected to the electromagnetic flowmeter detector. By forming the range of the thickness coefficient (hatched area) as shown in FIG.
The maximum stress generated can be set to the maximum stress value σ max of the material or less.

As a result, it was confirmed that the stress was dispersed over the entire measuring pipe reinforcing collar 23 and the pipe connecting flange 4. Thus, in the first embodiment,
At both ends of the measurement pipe 1, a double-structured flange portion 20 in which a pipe connection flange 21 and a coil chamber side plate 22 are integrally formed via a measurement pipe reinforcement collar 23 is provided, and the thickness of the measurement pipe reinforcement collar 23 is set. Is the electromagnetic flow meter detector
Since it was formed to 0.01D to 0.6D when expressed as
The welding points between the pipe connection flange 21 and the coil chamber side plate 22 are reduced to eliminate airtight leaks, work cost is reduced, and a welding work space is not required, whereby the total length can be shortened.

Further, since the end face portion of the measuring pipe 1 which is a portion where mechanical stress acts is reinforced by the double structure flange portion 20, the measuring pipe 1 can be made thin and lightweight.
Strength measurement using the finite element method by modeling the measurement pipe 1 and the double structure flange portion 20 for the purpose of size reduction for dispersing and relaxing the stress concentrated at the root of the pipe connection flange 21. Analyzed according to
By forming the wall thickness of 3 in the range of 0.01D to 0.6D, the wall thickness of the measuring pipe 1 can be reduced, and at the same time, necessary and sufficient strength against pipe stress can be provided, and the size and weight can be reduced. Further, cost reduction can be realized. (2) Next, a second embodiment of the present invention will be described. The same parts as those in FIG. 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a configuration diagram showing a portion of a pipe connecting flange of the electromagnetic flow meter detector. At both ends of the measuring pipe 30, a double-structured flange portion 34 in which a pipe connecting flange 31 and a coil chamber side plate 32 are integrated via a measuring pipe reinforcing collar 33 is integrally formed.

The thickness of the measuring pipe reinforcing brim 33 is 0.0 when the nominal diameter of the electromagnetic flowmeter detector is expressed as D in the same manner as above.
It is formed in 1D to 0.6D. Further, the double structure flange portion 34 is formed of a functionally graded material in which the inner surface side, that is, the inner surface side that is also the inner surface side of the measuring tube 30 is made of a non-magnetic material, for example, SUS, and the outer peripheral side is made of carbon steel SS.

That is, the inner surface of the measuring pipe 30 is made of a non-magnetic material, and the double structure flange portion 34 is made of carbon steel. With such a configuration, welding points between the pipe connection flange 21 and the coil chamber side plate 22 are reduced to eliminate airtight leaks, work cost is reduced, and a welding work space is not required, so that the entire length is increased. Can be shortened.

Particularly, the welding work can be omitted, the airtightness can be improved, and the cost can be reduced. or,
Since the end face portion of the measuring pipe 30, which is a portion where mechanical stress acts, is reinforced by the double-structured flange portion 34, the measuring pipe 30 can be made thin and lightweight.

Further, analysis is performed by strength calculation using the finite element method, and the wall thickness of the measuring pipe reinforcing collar 33 is 0.01D to
By forming it to 0.6D, the wall thickness of the measuring tube 30 can be reduced, and at the same time, necessary and sufficient strength against pipe stress can be provided, and the size and weight can be reduced and the cost can be reduced. .

The present invention is not limited to the first and second embodiments described above, but may be modified as follows. For example, in the second embodiment, the double structure flange portion 34
Is made of a functionally graded material whose inner surface is made of a non-magnetic material and whose outer surface is made of carbon steel.
00 or SUS304. Even with such a structure, the welding work can be omitted, the airtightness can be improved, and the cost can be reduced.

[0057]

As described in detail above, according to the present invention, it is possible to prevent a situation such as destruction due to excessive stress concentration, improve airtightness, and achieve overall weight reduction and cost reduction. A total detector can be provided.

[Brief description of drawings]

FIG. 1 is a structural diagram showing a first embodiment of an electromagnetic flow meter detector according to the present invention.

FIG. 2 is a schematic diagram showing a state in which a bending moment is applied to the end surface of the measuring pipe.

FIG. 3 is a characteristic diagram showing the magnitude of bending moment in the pipe axis direction when a bending moment acts on the end surface of the measuring pipe.

FIG. 4 is a characteristic diagram showing the generated stress with respect to the thickness of the measuring pipe reinforcing collar at an outlet diameter of 50A.

FIG. 5 is a characteristic diagram showing the relationship between the thickness of the measuring pipe reinforcing collar and the nominal diameter at each nominal diameter.

FIG. 6 is a structural diagram showing a second embodiment of the electromagnetic flow meter detector according to the present invention.

FIG. 7 is a structural diagram of a conventional electromagnetic flowmeter detector.

FIG. 8 is a structural diagram of a flange portion for pipe connection of the electromagnetic flow meter detector.

FIG. 9 is a structural diagram of another flange portion for pipe connection of the electromagnetic flow meter detector.

[Explanation of symbols]

1, 30 ... Measuring tube, 7 ... Lining, 8 ... Electrode, 9 ... Excitation coil, 10 ... Coil chamber outer peripheral plate, 20, 34 ... Double structure flange portion, 21, 31 ... Piping connection flange, 2
2, 32 ... Coil chamber side plate, 23, 33 ... Measuring tube reinforcing collar.

Claims (3)

[Claims] 1. An electromagnetic flowmeter detector in which an exciting coil is installed on an outer peripheral portion of a measuring tube, wherein a pipe connection flange and a coil chamber side plate for accommodating the exciting coil are provided at both ends of the measuring tube. A double structure flange portion integrally formed through a reinforcing collar is provided, and the thickness of the measuring tube reinforcing collar is 0.01D when the nominal diameter of the electromagnetic flowmeter detector is represented as D. An electromagnetic flowmeter detector characterized in that it is formed to 0.6D. 2. An electromagnetic flowmeter detector in which an exciting coil is installed on an outer peripheral portion of a measuring pipe, wherein a pipe connection flange and a coil chamber side plate for accommodating the exciting coil are provided for both ends of the measuring pipe. When the double-structured flange portions that are integrated via the measuring pipe reinforcing flange are integrally formed, and the thickness of the measuring pipe reinforcing flange is expressed as the nominal diameter of the electromagnetic flowmeter detector is D An electromagnetic flowmeter detector characterized by being formed to 0.01D to 0.6D. 3. The electromagnetic flowmeter detector according to claim 2, wherein the double structure flange portion is formed of a functionally graded material having an inner surface side made of a non-magnetic material and an outer circumference side made of carbon steel.