JPS61271419A - Manufacture of measuring pipe for minute electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To enable the passage of a fluid to be measured to be formed with a high dimensional accuracy and a smooth inner wall surface by coating the surface by a lining material made from a thermoplastic resin and applying a machining or the like to the surface. CONSTITUTION:A pipe member 11 with flanges on both ends is provided with a stepped portion 13 formed on the central portion of an inner wall 11a in the axial direction of the member 11. An insulative lining material 14 is made from a thermoplastic resin material and provided on the inner wall 11a and end surfaces 12a. The inner wall 14a of the lining material 14 is formed with a smooth surface and a projected portion 16 is formed in the position corresponding to the stepped portion 13. The inner wall 11a and the end surfaces 12a are coated with the lining material 14 of the thermoplastic resin. Then, after the pipe member 11 is machined to be formed with a passage 17 having both end openings with diameters larger than that of the central portion, a forming trowel that conforms to a predetermined passage and heated to about 420 deg.C is inserted in the passage 17 from one side opening to form this one side opening of the passage 15 of a fluid to be measured. The other side opening of the passage 15 is processed in the same manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a measurement tube for a microelectromagnetic flowmeter having a micro-diameter flow path.

[Conventional technology]

Conventionally, the manufacturing method for measuring tubes for this type of microelectromagnetic flowmeter includes:
The inner wall 1a of the pipe member 1 and the end surface 2a of the flange 2 shown in FIG. 4 are covered with an insulating lining 3 as shown by chain lines in the figure, and then a fluid flow path 4 to be measured is formed in the insulating lining 3 by machining. There is a method that manufactures the measuring tube 5 using the same method.

By the way, in this type of measurement tube for a microelectromagnetic flowmeter, for example, when a connection pipe (not shown) with a pipe diameter that is not so small according to the 15A or IOA standard is connected, or when the pressure loss during measurement is reduced as much as possible. In order to reduce the size, a throttle 6 is provided at the center in the axial direction of the fluid flow path 4 to be measured, so that the fluid flow path 4 to be measured has high dimensional accuracy and is formed with a smooth flow path wall surface 4a. is required.

[Problem that the invention seeks to solve]

However, in the conventional manufacturing method of a measurement tube for a micro-electromagnetic flowmeter, the fluid flow path 4 to be measured is formed by machining, so it is extremely difficult to satisfy the above-mentioned requirements.

[Means for solving problems]

The method for manufacturing a measurement tube for a microelectromagnetic flowmeter according to the present invention includes coating the inner wall of a tube member with a lining material made of thermoplastic resin;
Next, this lining material is machined to form a communication hole in which both openings have a larger hole diameter than the hole in the center,
Thereafter, a heated shaping iron that conforms to a predetermined flow path shape is inserted into the flow hole to form a fluid flow path to be measured.

[For production]

In the present invention, the inner wall of the pipe member is covered with a lining material made of thermoplastic resin, and the lining material is then machined to form a communication hole in which both openings have a diameter larger than that of the center part. Afterwards, the fluid flow path to be measured is formed by inserting a heating molding iron that conforms to the predetermined flow path shape into the flow hole. A measuring fluid flow path can be formed.

[Example] FIG. 2 is a sectional view showing a measurement tube for a microelectromagnetic flowmeter manufactured by the manufacturing method according to the present invention.

In the figure, the reference numeral 11 indicates a SUS tube member having flanges 12 at both ends, and has inner walls 1 ], a
A stepped portion 13 having both end surfaces 13a formed of Taber surfaces is provided at the central portion in the axial direction.

14 is an insulating lining material made of Teflon PFA.
It is made of a thermoplastic resin material such as, and is provided on the inner wall 11a of the tube member 11 and the end surface I2a of the flange 12. The inner wall 14a of this lining material 14 is entirely formed of a smooth surface, and a protrusion 16 forming a constriction 15a of the fluid flow path 15 to be measured is formed at a portion corresponding to the step 13 of the tube member 11. is provided.

Next, a method for manufacturing a measuring tube for a microelectromagnetic flowmeter having the above-described configuration using FIG. 1 (al~(C1) will be described.

First, as shown in FIG.
Cover with Next, as shown in FIG. 1, a communication hole 17 is formed in the lining material 14 by machining, both openings of which have a diameter larger than that of the central hole. After that,
As shown in FIG. , forming one side of the fluid flow path 15 to be measured.In this case, an electric iron having a stopper 18a is used as the molding iron 18, and the pipe member 11 is positioned by a positioning stand 19. .And the pipe member 1
1, the other side of the fluid flow path 15 to be measured is formed by inserting the molding iron 18 into the flow hole 17 from the other opening in the same manner as described above.

In this way, a measurement tube for a micro electromagnetic flowmeter can be manufactured reliably.

According to the manufacturing method of the present invention, the lining material 1
The fluid flow path 15 to be measured is formed by inserting a molding iron 18 that fits a predetermined flow path shape into the flow hole 17 of No. A fluid flow path 15 can be formed.

In this example, the time required to form the fluid flow path 15 to be measured using the forming trowel 18 is approximately 1 minute.

Further, in the embodiment, the molding iron 18 used when forming the fluid flow path 15 to be measured is shown as having a stove/bar 18a, but the present invention is not limited to this. As shown in FIG. 3, it is also possible to use a forming iron 20 without a stopper.
The molding iron 20 is inserted into the positioning table 21 in the inserted state.
A stopper 2' 1a for positioning is provided.

Further, the shape of the tube member 11 according to the present invention is not limited to the above-described embodiments, and may be a tube member having a uniform inner diameter, for example, and the shape can be changed as appropriate.

〔Effect of the invention〕

As explained above, according to the present invention, the inner wall of the pipe member is covered with a lining material made of thermoplastic resin, and then this lining material is machined so that both openings thereof have a hole diameter larger than that of the central portion. The flow path for the fluid to be measured is formed by forming a hole and then inserting a heated forming trowel that conforms to the predetermined flow path shape into the flow hole, resulting in high dimensional accuracy and smooth flow. It is possible to reliably and easily obtain a measuring tube for a microelectromagnetic flowmeter in which a fluid flow path to be measured is formed with a wall surface having a smooth surface.

[Brief explanation of drawings]

FIGS. 1(a), 1(c) are cross-sectional views for explaining the method for manufacturing a measuring tube for a microelectromagnetic flowmeter according to the present invention,
Fig. 2 is a sectional view showing a measuring tube for a micro-electromagnetic flowmeter manufactured by the manufacturing method, Fig. 3 is a sectional view for explaining another embodiment, and Fig. 4 is a sectional view for a conventional micro-electromagnetic flowmeter. FIG. 3 is a cross-sectional view for explaining a method of manufacturing a measuring tube. 11... Pipe member, lla... Inner wall, 14...
・Lining material, 15... Fluid flow path to be measured, 17.
... Distribution hole, 18 ... Molding iron.

Claims (1)

[Claims] The inner wall of the tube member is covered with a thermoplastic resin lining material, and then a communication hole is formed in this lining material by machining, both openings of which have a diameter larger than that of the central portion, and then the inside of this communication hole is 1. A method of manufacturing a measuring tube for a microelectromagnetic flowmeter, characterized in that a flow path for a fluid to be measured is formed by inserting a molding iron that conforms to a predetermined flow path shape in a heated state.