JPH08219833A - Lining pipe and manufacture thereof - Google Patents

Abstract

PURPOSE: To eliminate the need of spot welding in a simple constitution, to surely set a perforated pipe in a pipe main body, and to enable injection molding of a lining material without shifting the perforated pipe. CONSTITUTION: A hole 22 for an electrode which has a projected edge 22a is formed on a perforated pipe 3, and the projected edge 22a is inserted and engaged with an electrode insert hole 21 of a pipe main body 1A. In such a condition, a lining material 2 is injection-molded. The axial movement of the perforated pipe 3 caused by the injection pressure is regulated and prevented by engaging the electrode insert hole 21 with the projected edge 22a mutually.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lining pipe suitable for application to a measuring pipe of an electromagnetic flow meter for measuring the flow rate of a conductive fluid and a method for manufacturing the lining pipe.

[0002]

2. Description of the Related Art An electromagnetic flow meter for measuring the flow rate of a conductive fluid flowing in a measuring pipe by utilizing an electromagnetic induction phenomenon
28411, etc.), in order to prevent a short circuit between an electromotive force which is a signal generated in a fluid and a measuring tube made of a non-magnetic material such as stainless steel, an inner wall surface which is a liquid contact surface of the measuring tube and The outer surface of the flange is covered with a lining material. Since the lining material is required to have excellent heat resistance, corrosion resistance, and insulation, an insulating material such as fluororesin is usually used, and the inner surface of the measuring tube and the outer surface of the flange are injection-molded from one direction on one side. Is injected and coated. However, since the lining material made of fluororesin has poor adhesion to metal and therefore easily peels off from the measuring pipe, a reinforcing pipe is usually embedded in the lining material covering the inner wall of the measuring pipe, whereby the lining material It is intended to prevent peeling (eg, Japanese Utility Model Publication No. 2-26025, Japanese Utility Model Publication No. 2-5191, and Japanese Utility Model Publication No. 1-7918).

FIG. 11 is a sectional view showing a conventional example of this type of electromagnetic flowmeter. In the figure, 1 is a measuring pipe 1, 2 is a lining material, and 3 is a reinforcing pipe embedded in the lining material 2. The measuring tube 1 is composed of a tube body 1A whose both ends are open and flange-shaped rings 1B and 1C which are joined to the opening portions of both ends of the tube body 1A by welding. The reinforcing tube 3 is made of a non-magnetic material such as SUS, has a large number of through holes 3a, and is coaxially arranged in the measuring tube 1 with a spacer 5 interposed therebetween at a constant interval. The spacer 5 is fixed to the measuring pipe 1 by welding, and the reinforcing pipe 3 is usually fixed to the spacer 5 by spot welding. Reference numeral 7 denotes a pair of electrodes (only one of which is shown), which is provided through the center of the wall of the measuring tube 1 so as to be orthogonal to the magnetic field of the exciting coil 6, 9 is a core covering the outer periphery of the exciting coil 6, and 10 is an electrode Reference numeral 7 is a signal lead wire, 11 is a cover for covering the outer circumference of the measuring tube 1, and 12 is a welding portion.

In such a structure, when the exciting coil 6 is energized and a conductive fluid is flown into the measuring tube 1, an average flow rate is generated between the pair of electrodes 7 which are orthogonal to the magnetic field direction and the fluid flow direction. A proportional electromotive force is generated, and the flow rate of the fluid can be measured by detecting this.

When manufacturing the measuring pipe 1, the joint A between the pipe body 1A and the flange-shaped rings 1B and 1C is butt-welded together, and then the spacer 5 is welded and fixed to the inner peripheral surface of the measuring pipe 1, The reinforcing pipe 3 is spot-welded to the spacer 5. This spot welding is for preventing the displacement of the lining material 2 due to its injection pressure during injection molding. Thereafter, the measuring tube 1 is set in a molding die, the lining material is injection-molded from one direction on one side, and the measuring tube is lined.

[0006]

However, when manufacturing the above-mentioned conventional measuring pipe 1, it is necessary to weld the spacer 5 to the measuring pipe 1 or spot weld the reinforcing pipe 3 to the spacer 5, so that However, there is a problem in that it takes a lot of man-hours and work takes time. In addition, it may be difficult to insert the welding machine into the pipe body, especially for the pipe body having a small diameter. Further, there is a problem that the number of parts is increased because the spacer is required. If the reinforcing pipe 3 shifts in the axial direction and projects to the outside of the lining material 2 during injection molding, the reinforcing strength of the lining material 2 decreases, and the escape holes for the electrodes are displaced, making it impossible to attach the electrodes. Or, again, insulation failure of the measuring tube 1 occurs and it cannot be used.

The present invention has been made in view of the above-mentioned conventional problems, and its object is to reliably set the reinforcing pipe in the pipe body without spot welding with a simple structure. It is an object of the present invention to provide a lining pipe capable of performing injection molding of a lining material without displacement of the reinforcing pipe, and a manufacturing method thereof.

[0008]

In order to achieve the above-mentioned object, the invention according to claim 1 is such that a reinforcing pipe is fixed coaxially with the pipe body in a lining material lined on the inner peripheral surface of the pipe body. In the lining pipe embedded at intervals, the engaging portions that prevent the reinforcement pipe from moving in the axial direction due to the injection pressure during the injection molding of the lining material by engaging the pipe body side and the reinforcement pipe with each other, respectively. It is characterized by being provided. According to a second aspect of the present invention, in a lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe body coaxially with the pipe body at a constant interval, A through hole is formed in the peripheral wall, and a protrusion portion is provided on the reinforcing pipe to prevent the reinforcing pipe from moving in the axial direction due to injection pressure during injection molding of the lining material by engaging with the through hole. And According to a third aspect of the present invention, in a lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe body coaxially with the pipe body at a constant interval, An annular groove is provided in the opening at one end, and a ring fitted in the annular groove is provided on the outer peripheral surface of the one end of the reinforcing pipe. According to a fourth aspect of the present invention, in a lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe body coaxially with the pipe body at a constant interval, It is characterized in that a protrusion is provided on the inner peripheral surface, and the protrusion is fitted into a positioning and fixing hole formed in the lining material. According to a fifth aspect of the present invention, in a lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval, the reinforcing pipe is Formed by winding a perforated plate into a cylindrical shape, an annular groove having step portions at both ends is provided on the inner peripheral surface of the pipe body, and the reinforcing pipe is fitted into the annular groove and both ends thereof are formed by the step portions. It is characterized by supporting. According to a sixth aspect of the present invention, in a lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval, An earth ring is disposed on the outer surface of the flange portion, and a support portion for restricting the axial movement of the reinforcing pipe and supporting the reinforcement pipe is provided on the earth ring.
According to a seventh aspect of the present invention, a reinforcing pipe is coaxially fitted and disposed on the inner peripheral surface of the pipe body via a spacer, and a flange ring is fitted on the outer peripheral surface of the opening end of the pipe body. The joint portion of the flange ring is welded, the reinforcing pipe is clamped and fixed by shrinking the inner diameter of the pipe body after welding, and then the pipe inner peripheral surface including the reinforcing pipe is covered with a lining material.

[0009]

In the invention described in claim 1, the engaging portions engage with each other to prevent the movement of the reinforcing pipe in the axial direction from being restricted. In the invention according to claim 2, the protrusion portion of the reinforcing pipe is fitted into the insertion hole of the pipe body to prevent the movement of the reinforcing pipe in the axial direction from being restricted. In the invention described in claim 3, the annular groove of the pipe body positions the ring of the reinforcing pipe, and functions as a stopper during injection molding of the lining material. In the invention according to claim 4, the positioning fixing hole of the reinforcing pipe and the projecting portion of the pipe body are fitted to each other to prevent the movement of the reinforcing pipe in the axial direction from being restricted. In the invention according to claim 5, the stepped portions at both ends of the annular groove formed in the tube body position the reinforcing pipe and support both ends thereof to prevent movement of the reinforcing pipe in the axial direction. In the invention according to claim 6, the supporting portion provided on the earth ring supports the reinforcing pipe to prevent the reinforcing pipe from moving in the axial direction. In the invention of claim 7, when a flange-shaped ring is fitted to the outer peripheral surface of the opening end of the pipe body and the joint is welded, the pipe body is shrunk due to shrinkage of the inner diameter of the pipe body after welding. Tighten and fix the reinforced pipe. Therefore, the pipe main body will not be displaced in the axial direction due to the injection pressure during the injection molding of the lining material.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view showing a first embodiment when the present invention is applied to a measuring pipe for an electromagnetic flow meter. In addition,
In the figure, the same components as those in FIG. 11 are designated by the same reference numerals, and the description thereof will be omitted. In the figure, 20
Is a cylindrical electrode mounting portion projecting on the peripheral wall of the tube body 1A,
Reference numeral 21 denotes an electrode insertion hole (engagement portion) into which the electrode 7 is inserted, and an electrode hole 22 having a protruding edge (projection portion) 22a as an engagement portion in the reinforcing tube 3 corresponding to the electrode insertion hole 21. Are formed. The protruding edge 22a of the electrode hole 22 can be easily formed by burring. And
The reinforcing tube 3 is inserted into the tube body 1A via the spacer 5, and the protruding edge 22a is inserted into the electrode insertion hole 21. The spacer 5 is the inner peripheral surface of the pipe body 1A or the reinforcing pipe 3.
Is welded and fixed to the outer peripheral surface of the.

2 (a) and 2 (b) show an example of the reinforcing pipe 3, where (a) is an example formed into a cylindrical body, and (b) is formed by winding a perforated plate 30 into a cylindrical shape. An example is shown (Actual Kaihei 2-5)
191). The reinforcing tube 3 of FIG. 2B is formed by winding a perforated plate 30 having a parallelogram shape into a cylindrical shape and abutting mutually facing edges 31a and 31b. Therefore, the end edges 31 a and 31 b are inclined with respect to the axis of the reinforcing pipe 3. When the reinforcing pipe 3 is inserted into the pipe main body, the porous plate 30 is rolled into a cylindrical shape and inserted into the pipe main body 1A, and when the gripped state by the hand is released, the reinforcing pipe 3 has its own elastic force. The diameter is expanded by the slit 3 between both ends.
2 is formed. Therefore, the both edges 31a and 31b are shown in FIG.
As shown in (3), the both ends 31a and 31b are brought into close contact with each other by relatively shifting in the axial direction so that the pipe diameter increases and the reinforcing pipe 3 is formed.

When the measuring tube 1 is manufactured, the reinforcing tube 3 is arranged in the tube body 1 via the spacer 5, and then the measuring tube 1 is set in the mold, and the lining in the molten state is formed as shown in FIG. The material 2 may be injected into the mold from one direction to cover the inner peripheral surface of the tube body 1A and the outer surface of the flange-shaped rings 1B and 1C. At this time, the reinforcement pipe 3 receives a force in the axial direction due to the injection pressure, but since the protruding edge 22a is inserted and engaged with the electrode insertion hole 21, it does not move in the axial direction,
The reinforcing pipe 3 can be embedded in the lining material 2.
Therefore, it is not necessary to spot weld the reinforcing pipe 3 to the spacer 5, the mounting work of the reinforcing pipe 3 is simple, and it is applicable to a measuring pipe having a small hole diameter. Further, if welding work of the reinforcing pipe 3 to the pipe body 1A is not necessary, welding slag does not adhere and the measuring pipe can be finished neatly. Furthermore, the electrode insertion hole 21 and the protruding edge portion 2
Since the reinforcing pipe 3 can be positioned in the rotation direction and the axial direction by the engagement of the 2a, it is not necessary to position the reinforcing pipe 3 with a jig or the like, and the mounting work of the reinforcing pipe 3 can be further simplified. can do. Therefore, the manufacturing of the measuring tube 1 is simple and easy, and the manufacturing cost can be reduced.

FIG. 5 is a sectional view of the essential parts showing a second embodiment of the present invention. In this embodiment, an annular groove 34 as an engaging portion is formed at one end of the inner peripheral surface of the pipe body 1A, and the spacer 5 and the ring 35 are joined and fixed to both ends of the outer peripheral surface of the reinforcing pipe 3 by welding or the like. 35 is fitted in the annular groove 34, and the lining material 2 is injection-molded into the mold from the annular groove 34 side to manufacture the measuring tube 1. When the lining material 2 is thus injected from the annular groove 34 side, the annular groove 34 functions as a stopper for the ring 35, so that the reinforcing pipe 3 does not move in the arrow direction due to the injection pressure, and axial positioning is easy. Thus, it can be surely buried at a predetermined position.

FIG. 6 is a sectional view of the essential parts showing a third embodiment of the present invention. In this embodiment, the inner end of the electrode mounting portion 20 is extended and protruded into the pipe body 1A, and the protruding portion 20a is used as an engaging portion with the reinforcing pipe 3. The protrusion 2 is provided on the reinforcing pipe 3.
A positioning / fixing hole 37 into which 0a is fitted is formed. Even in such a configuration, the protrusion 20a and the positioning and fixing hole 37 are engaged with each other, whereby the movement of the reinforcing pipe 3 in the axial direction during the injection formation of the lining material 2 can be reliably prevented, so that the reinforcing pipe 3 is prevented. Need not be fixed by welding to the measuring tube 1, and the number of welding steps can be reduced.

FIG. 7 is a sectional view of the essential portions showing the fourth embodiment of the present invention. In this embodiment, an annular groove 38 is formed on the inner peripheral surface of the measuring tube 1.
And the reinforcing pipe 3 is fitted and arranged in the annular groove 38. Since the annular groove 38 is formed over substantially the entire length of the measuring tube 1, the end portion is located near the end portion of the measuring tube 1, and step portions 39 as engaging portions are formed at both end portions, respectively. The reinforcement pipe 3 is provided by the step 39.
It supports the end of each. As the reinforcing pipe 3, the one shown in FIG. 2B, that is, the one formed by winding the perforated plate 30 into a tubular shape so that it can be fitted into the annular groove 38, is used. The end portion of the reinforcing pipe 3 is engaged with the step portion 39 to form an engaging portion. Even in such a configuration, since the step portion 39 of the annular groove 38 functions as the positioning and stopper of the reinforcing pipe 3 as in the embodiment shown in FIG. 5, the axial positioning of the reinforcing pipe 3 is easy and the lining is easy. It is possible to reliably prevent the axial movement of the reinforcing pipe 3 during injection molding of the material 2. Further, since the spacer 5 is not required, the number of parts can be reduced.

FIG. 8 is a sectional view of the essential parts of a fifth embodiment of the present invention, and FIG. 9 is a front view of the essential parts of the earth ring. In this embodiment, the earth ring 40 attached to the outer surface of the flange-shaped rings 1B and 1C is provided with a supporting portion 41 as an engaging portion, and the supporting portion 41 supports the end portion of the reinforcing pipe 3. is there. Earth ring 40 is ring 1
It is electrically connected to the outer peripheral surfaces of B and 1C, and its inner peripheral portion is in contact with the measuring fluid so that the measuring fluid is grounded and kept at the reference potential, and is usually made of tantalum, platinum or the like ( Japanese Utility Model Publication No. 3-55064). The support part 41 is formed by bending a part of the liquid contact part 40 a projecting from the inner circumference of the earth ring 40 at a substantially right angle to the center direction of the measuring tube 1. Even in such a configuration, since the reinforcement pipe 3 is positioned and supported by the support portion 41, it is not necessary to spot weld the reinforcement pipe 3 to the measurement pipe 1, and the support portion 41 moves the reinforcement pipe 3 in the axial direction. In order to prevent the restriction, the measuring tube 1 can be securely fixed at a predetermined position without being displaced when the measuring tube 1 is lined. Further, similarly to the fourth embodiment shown in FIG. 7, the spacer is unnecessary and the number of parts can be reduced.

FIG. 10 is a diagram for explaining a method of manufacturing a lining pipe according to the present invention. This manufacturing method uses reinforcing pipe 3
Is previously inserted and arranged in the pipe body 1A via the spacer 5, and the shrinkage fitting effect by welding the pipe body 1A and the flange-shaped rings 1B and 1C moves the reinforcing pipe 3 to the pipe body 1A in the axial direction. It is designed to be prevented and fixed.
The spacer 5 is welded and fixed to the inner peripheral surface of the tube body 1A or the outer peripheral surface of the reinforcing tube 3.

When the measuring tube 1 is manufactured, the reinforcing tube 3 is coaxially fitted and disposed on the inner peripheral surface of the tube body 1A through the spacer 5, and the flange-shaped ring 1 is formed on the outer peripheral surface of the opening end of the tube body 1A.
B and 1C are fitted together, and pipe body 1A and flange-shaped ring 1
The measuring tube 1 is manufactured by welding the joint portions 43 of B and 1C.
When the temperature of the joint 43 drops after welding is completed, the pipe body 1A
The inner diameter in the vicinity of the welded portion is contracted, and the reinforcing pipe 3 is tightened and shrink-fitted. Therefore, the measuring pipe 1 and the reinforcing pipe 3 are integrally connected, and the movement of the reinforcing pipe 3 in the axial direction can be reliably prevented. Thereafter, the inner surface of the tube body 1 including the reinforcing tube 3 and the outer surfaces of the flanged rings 1B and 1C are covered with a lining material to manufacture a measuring tube.

In such a manufacturing method, since the shrinkage fitting effect can prevent the movement of the reinforcing pipe 3 in the axial direction, the lining material 2 of the lining material 2 can be prevented as in the first to fifth embodiments. It is possible to reliably prevent the axial movement of the reinforcing pipe 3 due to the injection pressure during injection molding. Also, the reinforcement pipe 3
Since it is not necessary to weld the pipe to the pipe body 1A, it is possible to reduce the number of welding steps and prevent welding slag from adhering.

In each of the above examples, a perforated plate was used as the reinforcing tube 3. However, the reinforcing tube 3 is not limited to this, and a wire mesh having a mesh-like hole formed by braiding wires is wound in a tubular shape. It may be the one that you had.

[0021]

As described above, in the lining pipe according to the present invention, the pipe main body side and the reinforcing pipe are provided with engaging portions respectively, and the engaging of these engaging portions causes the reinforcing pipe to move in the axial direction. Therefore, even if the reinforcement pipe is not fixed to the pipe body by welding, it is possible to reliably prevent the reinforcement pipe from moving in the axial direction due to the injection pressure of the lining material during injection molding. Therefore, the number of welding steps can be reduced, and even a lining pipe having a small hole diameter can be manufactured easily and the manufacturing cost can be reduced. Further, in the invention described in claims 5 and 6, since the spacer is not required, the number of parts can be reduced.

The method of manufacturing a lining pipe according to the present invention is
Since the reinforcing pipe is shrunk by shrinkage accompanying cooling of the welded portion after welding the pipe body and the flanged ring, the reinforcing pipe moves in the axial direction by the injection pressure when the lining material is formed by injection. Can be reliably prevented. Therefore, the number of welding steps can be reduced,
The lining pipe can be manufactured easily and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment when the present invention is applied to a measuring pipe of an electromagnetic flow meter.

2A and 2B are perspective views of a reinforcing pipe, respectively.

FIG. 3 is a perspective view of a reinforcing tube formed by winding a perforated plate into a cylindrical shape.

FIG. 4 is a view for explaining injection molding of a lining material.

FIG. 5 is a cross-sectional view of essential parts showing a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts showing a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of essential parts showing a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view of essential parts showing a fifth embodiment of the present invention.

FIG. 9 is a front view of a main part of an earth ring.

FIG. 10 is a diagram for explaining the method of the present invention.

FIG. 11 is a cross-sectional view showing a conventional example of an electromagnetic flow meter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Measuring tube, 1A ... Tube body, 1B, 1C ... Flange ring, 2 ... Lining material, 3 ... Reinforcing tube, 5 ... Spacer,
6 ... Exciting coil, 20 ... Electrode mounting portion, 20a ... Projection portion,
21 ... Electrode insertion hole, 22 ... Electrode hole, 22a ... Projected edge,
30 ... Perforated plate, 34 ... Annular groove, 35 ... Ring, 37 ... Positioning and fixing hole, 38 ... Annular groove, 39 ... Step portion, 40 ...
Earth ring, 41 ... Supporting portion, 43 ... Welding portion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Eiji Ohnaka Eiji Ohnaka 4-1-1 Omagari, Samukawa-cho, Takaza-gun, Kanagawa Yamatake Honeywell Co., Ltd. Shonan Plant (72) Inventor Shingo Komatsu Omagari-shi, Samukawa-cho, Takaza-gun, Kanagawa Prefecture 1-1-1 Sanmu Honeywell Co., Ltd. Shonan Factory (72) Inventor Akira Yahagi 4-1-1 Omagari, Samukawa-cho, Takaza-gun, Kanagawa Yamatake Honeywell Co., Ltd. Shonan Factory

Claims (7)

[Claims] 1. A lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval, wherein the pipe main body side and the reinforcing pipe are provided. A lining pipe, characterized in that each lining pipe is provided with an engaging portion which is engaged with each other to prevent axial movement of the reinforcing pipe due to injection pressure during injection molding of the lining material. 2. A lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe body coaxially with the pipe body at a constant interval, and an insertion hole is formed in a peripheral wall of the pipe body. The lining pipe is characterized in that a protrusion is formed on the reinforcing pipe to prevent movement of the reinforcing pipe in the axial direction due to injection pressure at the time of injection molding of the lining material by engaging with the insertion hole. . 3. A lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval, and at one end opening of the pipe main body. A lining pipe comprising an annular groove, and a ring fitted in the annular groove provided on an outer peripheral surface of one end of the reinforcing pipe. 4. A lining pipe in which a reinforcing pipe is embedded in a lining material lined on the inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval. A lining pipe characterized in that a protrusion is provided and the protrusion is fitted into a positioning and fixing hole formed in the lining material. 5. A lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval, wherein the reinforcing pipe is a cylindrical porous plate. It is formed by winding in a circular shape, and an annular groove having step portions at both ends is provided on the inner peripheral surface of the tube body, and the reinforcing pipe is inserted into the annular groove so that both end portions are supported by the step portion. Characterized lining tube. 6. A lining pipe in which a reinforcing pipe is embedded in a lining material lined on an inner peripheral surface of the pipe main body coaxially with the pipe main body at a constant interval, wherein an outer surface of a flange portion of the pipe main body. A lining pipe, in which an earth ring is provided on the ground ring, and a support portion for restricting the axial movement of the reinforcing pipe and supporting the reinforcement pipe is provided on the earth ring. 7. A pipe main body and a flange-shaped ring, wherein a reinforcing pipe is coaxially fitted and disposed on an inner peripheral surface of the pipe main body via a spacer, and a flange-shaped ring is fitted on an outer peripheral surface of an opening end portion of the pipe main body. The lining is characterized in that the joint portion is welded and the reinforcing pipe is clamped and fixed by shrinking the inner diameter of the pipe body after welding, and then the inner peripheral surface of the pipe body including the reinforcing pipe is lined by injection molding of the lining material. Pipe manufacturing method.