JPH0548845B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a measurement method for a micro-electromagnetic flowmeter that has a micro-diameter flow channel with a hole diameter smaller than the openings at both ends in the axial center of the fluid flow channel to be measured. This invention relates to a method of manufacturing a tube.

[Conventional technology]

Conventionally, a method for manufacturing a measurement tube for a microelectromagnetic flowmeter of this type includes covering the inner wall 1a of the tube member 1 and the end surface 2a of the flange 2 with an insulating lining 3 as shown by chain lines in the figure, as shown in FIG. Then, there is a method in which a measurement tube 5 is manufactured by forming a fluid flow path 4 to be measured within the insulating lining 3 by machining.

By the way, in the measurement tube for this type of microelectromagnetic flowmeter, for example, there are cases where a connection pipe (not shown) with a diameter that is not so small with a standard of 15A or 10A is connected, or when the pressure loss during measurement is minimized. In this case, an aperture 6 is formed in the axial center of the fluid flow path 4 to be measured, which serves as a micro-diameter flow path having a smaller hole diameter than the flow hole portions at both ends connected to the connecting pipes. This is because while the diameter of the connecting pipe connected to the measurement tube is determined by standards and specifications, the pore diameter of the measurement part of the measurement tube must be made smaller depending on the minute flow rate and flow velocity of the fluid to be measured. This is because there is.

In the case of the fluid flow path 4 to be measured having the throttle 6 as described above, the throttle 6 is arranged so as not to cause pressure loss or flow turbulence in the flow hole portions with large diameters at both ends. It is required that the tapered surface for connection be formed with high dimensional accuracy and a smooth channel wall surface 4a.

[Problem that the invention seeks to solve]

However, in the conventional method of manufacturing a measurement tube for a microelectromagnetic flowmeter, the fluid flow path 4 to be measured, which has the above-mentioned throttle 6 and tapered surfaces on both ends thereof, is
Since it is formed by machining, it has been extremely difficult to satisfy the above-mentioned requirements.

[Means for solving problems]

The method of manufacturing a measurement tube for a microelectromagnetic flowmeter according to the present invention includes forming a fluid flow path to be measured having a micro-diameter flow path with a hole diameter smaller than the openings at both ends in the center of the tube member in the axial direction. First, a through hole having a diameter equal to that of the micro-diameter flow path is formed in the inner wall of the pipe member, and then a thermoplastic resin lining material is coated on both ends of the through hole of this lining material. , a flow hole having a diameter larger than that of the micro-diameter flow path is formed by machining, and then a flow path shape having the shape of the fluid flow path to be measured is formed in the flow hole at both ends and the center portion of the through hole. A fluid flow path to be measured is formed by inserting a suitable molding iron in a heated state.

[Effect]

According to the present invention, the inner wall of the pipe member is coated with a thermoplastic resin lining material with a through hole having a diameter suitable for a micro-diameter flow path, and then the through hole of the lining material is covered with a through hole at both ends. A flow hole having a large diameter is formed by machining from the side, and then a heated forming trowel that conforms to the predetermined shape of the flow path is inserted into these flow holes and the central through hole portion. This makes it possible to form a fluid flow path to be measured with high dimensional accuracy and a smooth wall surface.

〔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 same figure, the reference numeral 11 indicates a SUS tube member having flanges 12 at both ends, and a stepped portion 13 having both end surfaces 13a tapered is provided at the axial center of the inner wall 11a. There is.
14 is an insulating lining material made of Teflon.
It is made of a thermoplastic resin material such as PFA, and is provided on the inner wall 11a of the tube member 11 and the end surface 12a of the flange 12. The inner wall 14a of this lining material 14 is entirely formed of a smooth surface, and a restriction 15a is provided at a portion corresponding to the step portion 13 of the tube member 11 to serve as a small-diameter flow path for the fluid flow path 15 to be measured. A protrusion 16 forming a smooth continuation is formed in the channel portions at both ends via a tapered surface.

Next, a method of manufacturing a measurement tube for a microelectromagnetic flowmeter having the above-described configuration will be explained using FIGS. 1a to 1c.

First, as shown in Figure a, the inner wall 11a of the tube member 11 having the stepped portion 13 in the axial center thereof and the end surface 12a of the flange 12 are penetrated with a hole diameter matching the aperture 15a which becomes the micro-diameter flow path. With the holes formed, it is covered with a lining material 14 made of thermoplastic resin. Next, as shown in Figure b, the lining material 14 is machined to form a communication hole 1 in which both openings have a larger hole diameter than the central hole.
form 7. Thereafter, as shown in FIG. 3c, a molding iron 18 that conforms to the predetermined flow path shape is inserted into the flow hole 17 from one opening along the axis of the flow hole 17 while being heated to 420°C. By this,
One side of the fluid flow path 15 to be measured is formed. In this case, an electric trowel having a stopper 18a is used as the forming trowel 18, and the tube member 11 is positioned by a positioning table 19. After inverting the tube member 11, the forming trowel 18 is inserted into the flow hole 17 from the other opening in the same manner as described above.
The other side of the fluid flow path 15 to be measured is formed by inserting the .

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 fluid flow path 15 to be measured is formed by inserting the forming trowel 18 that conforms to a predetermined flow path shape into the flow hole 17 of the lining material 14. Fluid flow path 1 to be measured with high dimensional accuracy and smooth wall surface
5 can be formed.

In this example, the time spent forming the fluid flow path 15 to be measured using the forming iron 18 is approximately 1.
minutes.

In addition, in the embodiment, the measured fluid flow path 15
Although a molding trowel 18 having a stopper 18a is shown as the molding trowel 18 used in forming the mold, the present invention is not limited to this, and as shown in FIG. 3, a molding trowel 20 without a stopper is used. I don't mind if you do that. In this case, the positioning base 21 of the pipe member 11
A stopper 21a is provided for positioning the molding iron 20 in the inserted state.

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 fluid flow path to be measured formed in the pipe member has a micro-diameter flow channel with a smaller hole diameter than the openings at both ends in the axial center of the fluid flow channel to be measured, and When manufacturing a measurement tube for a microelectromagnetic flowmeter in which both end surfaces of a diameter channel are formed as tapered surfaces, a through hole having a hole diameter matching the micro diameter channel is formed in the inner wall of the tube member. Covered with thermoplastic resin lining material,
Next, on both ends of the through-hole of this lining material, flow holes having a hole diameter larger than the micro-diameter flow path are formed.
The fluid flow path to be measured is formed by mechanical processing, and then heated and inserted into the central portion of the flow holes at both ends and the through hole to form a molding iron that matches the flow path shape of the fluid flow path to be measured. Since the measurement fluid flow path is formed, it is possible to easily and reliably obtain a measurement tube for a microelectromagnetic flowmeter in which a measurement fluid flow path with high dimensional accuracy and a smooth wall surface is formed.

In particular, according to the present invention, when lining the inside of a pipe member, after forming a through hole with a hole diameter that matches the micro-diameter flow path that is important for micro flow measurement, the through hole is Machine processing is performed from both ends of the hole to form a large diameter flow hole, and then a heated forming trowel is inserted to form a flow path for the fluid to be measured with the desired flow path shape. from,
This fluid flow path to be measured, especially the micro-diameter flow path that requires concentricity and smoothness in the axial direction, and the tapered surfaces at both ends can be easily and reliably formed with high dimensional accuracy and smooth channel walls. can do.

[Brief explanation of drawings]

Figures 1a, b, and c are cross-sectional views for explaining the method of manufacturing a measuring tube for a microelectromagnetic flowmeter according to the present invention, and Figure 2 shows a measuring tube for a microelectromagnetic flowmeter manufactured by the manufacturing method. FIG. 3 is a sectional view for explaining another embodiment, and FIG. 4 is a sectional view for explaining a conventional method of manufacturing a measuring tube for a microelectromagnetic flowmeter. DESCRIPTION OF SYMBOLS 11... Pipe member, 11a... Inner wall, 14... Lining material, 15... Fluid flow path to be measured, 17...
Distribution hole, 18...molding trowel.

Claims (1)

[Scope of Claims] 1. A fluid flow path to be measured formed in a pipe member has a micro-diameter flow channel with a hole diameter smaller than the openings at both ends in the axial center thereof, and the micro-diameter flow channel has a A method for manufacturing a measurement tube for a microelectromagnetic flowmeter having both end surfaces formed as tapered surfaces, the method comprising: forming a through hole having a diameter matching the micro-diameter flow path in the inner wall of the tube member; A lining material made of plastic resin is coated, and then flow holes having a diameter larger than the micro-diameter flow path are formed at both ends of the through-hole of the lining material by machining, and then the flow at both ends is The fluid flow path to be measured is formed by inserting a heated shaping iron that matches the flow path shape of the fluid flow path to be measured into the center portion of the hole and the through hole. A method for manufacturing a measuring tube for a microelectromagnetic flowmeter.