JP2005114657A - Vortex flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make full airtight seal, and to fully secure attaching strength for a vortex-detecting member. <P>SOLUTION: In this vortex flowmeter, air-tight sealing is carried out by an engaging portion between a vortex-detecting member attaching hole 18 of a measuring instrument body 11 and an engaging part 23 of the vortex-detecting member 21, and the vortex detecting member 21 is fixed separately therefrom onto the measuring instrument body 11 by a resin welding part 32 between a vortex-detecting member, holding cylindrical part 16 of the measuring instrument body 11, and a base part 22 of the vortex-detecting member 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vortex flowmeter, and more particularly to a mounting structure for a vortex detection member in a vortex flowmeter.

  As a flowmeter that measures the flow rate of fluid flowing through a pipe, a pipe flow path is formed in the measuring instrument body (casing), and the vortex generated by the vortex generator provided in the pipe flow path is attached to the measuring instrument body. There is known a Karman vortex flow meter (vortex flow meter) that is detected by a vortex detector built in the vortex detection member (for example, Patent Documents 1 and 2).

  In the conventional vortex flowmeter, the vortex detection member is attached to the measuring instrument main body by inserting the vortex detecting member into the vortex detecting member mounting hole formed in the wall that defines the pipe flow path and detecting the vortex. The flange part formed at the end of the member is screwed directly to the measuring instrument main body with a mounting screw inserted into a screw through hole penetrating the flange part, or a holding metal fitting is placed on the flange part, This is performed by inserting a mounting screw into a screw-through hole penetrating the presser fitting and the flange portion, and screwing it to the measuring instrument main body through the presser fitting (for example, Patent Documents 3, 4, and 5).

  In the vortex detecting member fixing structure in this vortex flowmeter, a plurality of mounting screws (bolts) are required to screw the flange portion to the measuring instrument body, and a tool is required to fix the vortex detecting member.

  Further, as an O-ringless vortex flowmeter, there is a vortex flowmeter having a structure in which a vortex detecting member is fused and fixed (ultrasonic welding, thermal welding) to a measuring instrument body (for example, Patent Documents 6 and 7).

  In this vortex flowmeter, since the fused part is thin, even if the hermetic seal can be performed by the fused part, the fixing strength is weak, and it is necessary to hold the fused part with a metal fitting and to fix it with screws. In ultrasonic welding, which is one of the fusion fixing methods, a ring-shaped jaw for concentrating ultrasonic energy is provided for reliable fusion, but only this jaw can secure a fixed area. Insufficient strength.

  Further, in heat welding, if heating is performed excessively to increase the welding area, the vortex detecting member may be deformed, and it is difficult to ensure the welding strength. Further, the fluid penetrates to the jaw portion of the welded portion, causing a liquid pool.

In addition, since the conventional vortex flowmeter does not have a structure that restricts the mounting direction of the vortex detection member in the circumferential direction, the orientation of the vortex detector in the vortex detection member varies with respect to the pipe, and accurate flow measurement is possible. Can no longer do.
JP-A-11-14412 JP 2000-321102 A JP-A-9-257529 JP 2002-333352 A JP 2003-42819 A JP 2002-195860 A JP 2002-323360 A

  The problem to be solved by the present invention is to perform a sufficient hermetic seal in a vortex flowmeter and to ensure a sufficient mounting strength of the vortex detecting member.

  The vortex flowmeter according to the present invention includes a vortex detection member in which a pipe flow path is formed inside a measuring instrument body, and a vortex generated by a vortex generator provided in the pipe flow path is attached to the measuring instrument body. In the vortex flowmeter for detecting by a vortex detector built in the vortex detector, the measuring instrument main body includes a vortex detecting member holding cylinder portion formed on an outer surface of the measuring instrument main body, and the vortex detection penetrating the measuring instrument main body. A vortex detection member mounting hole that communicates the inside of the member holding cylinder and the inside of the pipe flow path is formed, and the vortex detection member includes a base that fits into the vortex detection member holding cylinder, and the vortex detection member mounting hole And a vortex detector and a vortex detector, and a vortex detector and a vortex detector. The base portion is resin welded.

  In the vortex flowmeter according to the present invention, preferably, the axial dimension of the base portion of the vortex detection member and the depth dimension of the vortex detection member holding cylinder portion are formed with different lengths, and the vortex detection member holding One of the base and the vortex detection member holding cylinder is protruded from the other in a state where the base is fitted to the cylinder, and an annular right angle corner is formed by the one and the other, and the resin Welding is performed by fillet welding over the entire circumference of the right-angled corner.

  Further, the vortex flowmeter according to the present invention has a tube flow path formed inside the measuring instrument body, and the vortex generated by the vortex generator provided in the pipe flow path is a vortex attached to the measuring instrument body. In the vortex flowmeter that detects the vortex detector built in the detection member, the measuring instrument main body includes a vortex detecting member holding cylinder formed on an outer surface of the measuring instrument main body, and the measuring instrument main body. A vortex detection member mounting hole is formed to communicate between the vortex detection member holding cylinder and the pipe flow path, and the vortex detection member includes a base that fits into the vortex detection member holding cylinder, and the vortex detection member A fitting portion that fits into the mounting hole and performs an airtight seal; and a sheath portion that incorporates the vortex detector and is disposed in the tube flow path, and is screwed to the vortex detection member holding cylinder portion The swirl nut-shaped cap member causes the vortex detection member to move to the measuring instrument body. It has been fixed.

  Further, the vortex flowmeter according to the present invention has a tube flow path formed inside the measuring instrument body, and the vortex generated by the vortex generator provided in the pipe flow path is a vortex attached to the measuring instrument body. In the vortex flowmeter that detects the vortex detector built in the detection member, the measuring instrument main body includes a vortex detecting member holding cylinder formed on an outer surface of the measuring instrument main body, and the measuring instrument main body. A vortex detection member mounting hole is formed to communicate between the vortex detection member holding cylinder and the pipe flow path, and the vortex detection member includes a base that fits into the vortex detection member holding cylinder, and the vortex detection member It has a fitting portion that fits into the mounting hole and performs an airtight seal, and a sheath portion that incorporates the vortex detector and is disposed in the tube flow path, and is non-reversely engaged with the measuring instrument main body. The vortex detection member is fixed to the measuring instrument body by a cap member with a check claw. There.

  In the vortex flowmeter according to the present invention, preferably, both the vortex detection member mounting hole and the fitting portion have a circular cross-sectional shape, and the vortex detection member holding cylinder portion and the base portion of the vortex detection member A concave and convex engaging portion that engages with each other to define a circumferential mounting position of the vortex detecting member with respect to the measuring instrument main body, and the concave and convex portions are inserted and fitted into the vortex detecting member mounting hole. The engaging portions engage with each other.

  In the vortex flowmeter according to the present invention, a hermetic seal is performed at the fitting portion between the vortex detecting member mounting hole of the measuring instrument main body and the fitting portion of the vortex detecting member. The vortex detection member is fixed to the measuring instrument main body by resin welding between the holding cylinder and the base of the vortex detecting member, or a cap nut with a cap nut and a cap member with a check claw are fixed to the measuring instrument main body. The Thereby, a sufficient hermetic seal can be performed at the fitting portion, and the mounting strength of the vortex detecting member can be sufficiently secured by resin welding different from the hermetic seal portion or fixing by the cap member.

  1 to 6 show one embodiment of a vortex flowmeter according to the present invention.

  As shown in FIGS. 1 and 2, the vortex flowmeter has a measuring instrument main body (casing) 11 as a main component. The measuring instrument body 11 is entirely composed of a fluororesin such as a PFA resin, a PTFE resin, or a PVDF resin. As shown in FIG. 3, the measuring instrument main body 11 has a straight pipe flow path 12, where one side of the pipe flow path 12 is a fluid inlet portion 13 and the other side is a fluid outlet portion 14. Yes.

  A vortex generator 15 is formed integrally with the measuring instrument main body 11 so as to extend vertically across the tube flow path 12. The vortex generator 15 is located on the fluid inlet portion 13 side in the pipe flow path 12 and is orthogonal to the flow direction of the fluid flowing in the pipe flow path 12 (left-right direction in FIGS. 2 and 3) (FIG. 3). It has a column shape extending in the vertical direction.

  As shown in FIG. 2, a cylindrical vortex detection member holding cylinder 16 is integrally formed on the upper part of the measuring instrument main body 11. The vortex detecting member holding cylinder portion 16 is on the downstream side of the vortex generator 15 when viewed in the flow of the fluid flowing in the pipe flow path 12. As shown in FIG. 3, the bottom of the vortex detecting member holding cylinder portion 16, in other words, the upper wall portion 17 of the pipe flow path 12 penetrates the upper wall portion 17 and vortex detecting member holding cylinder. A vortex detecting member mounting hole 18 that communicates the inside of the portion 16 and the inside of the pipe flow path 12 is formed through. The vortex detection member mounting hole 18 is a hole having a circular cross-sectional shape having an inner diameter sufficiently smaller than the inner diameter of the vortex detection member holding cylinder portion 16. A circumferential groove 19 having a semi-cylindrical cross section (semi-circular cross section) is formed on the inner peripheral surface in the vicinity of the opening end of the vortex detecting member mounting hole 18 with respect to the pipe flow path 12.

  Further, as shown in FIG. 2, the vortex detection member holding cylinder part 16 has two slits 20 for circumferential alignment that are rotated 180 degrees in the circumferential direction of the vortex detection member holding cylinder part 16. As shown in FIG. 1, each slit 20 opens in the upper end surface 16 </ b> A of the vortex detection member holding cylinder portion 16 and extends in the axial direction of the vortex detection member holding cylinder portion 16. doing.

  As shown in FIGS. 2 and 4, the vortex detection member 21 is fitted in the vortex detection member holding cylinder portion 16. The vortex detecting member 21 is made of a fluororesin such as a PFA resin, a PTFE resin, and a PVDF resin, like the measuring instrument main body 11.

  As shown well in FIG. 5, the vortex detecting member 21 has a circular cross section base 22 that fits into the vortex detecting member holding cylinder 16 and a circular cross section that fits into the vortex detecting member mounting hole 18. A fitting portion 23 having a shape and a sheath portion 24 having a flat cross-sectional shape located in the pipe flow path 12, and a ring-shaped ridge 25 on the outer peripheral surface of the fitting portion 23. Is formed.

  As shown in FIG. 3, the cross-sectional shape of the ring-shaped protrusion 25 is a kamaboko-shaped cross-section (semi-circular cross-section) so as to complement the cross-sectional shape of the circumferential groove 19. The outer diameter of the ridge portion 25 is larger than the maximum inner diameter of the circumferential groove 19.

  By fitting and inserting the fitting portion 23 into the vortex detecting member mounting hole 18, the ring-shaped protrusion 25 is fitted into the circumferential groove 19 in an elastically deformed state. Thereby, the attachment position of the vortex detection member 21 in the axial direction with respect to the measuring instrument main body 11 is determined, and an airtight seal between the vortex detection member attachment hole 18 and the fitting portion 23 is performed.

  This hermetic seal is surely performed in a close contact state obtained by elastic deformation of the ring-shaped protrusion 25 made of fluororesin rich in elasticity and the circumferential groove 19 (measuring instrument body 11). Further, this hermetic seal is performed at a position very close to the pipe flow path 12 depending on the arrangement position of the ring-shaped protrusion 25 and the circumferential groove 19, and does not create a dead space in which dust is collected. When the cleanliness of a fluid such as a fluid is required, the cleanliness of the fluid is not impaired by discharging impurities from the dead space.

  The sheath portion 24 is located in the tube flow path 12 at a position downstream of the vortex generator 15 as viewed from the flow of the fluid flowing in the tube flow path 12, and the sheath portion 24 is flattened by a piezoelectric element. A vortex detector 26 having a shape (strip shape) is arranged. That is, the sheath portion 24 incorporates the vortex detector 26 at a position downstream of the vortex generator 15 when viewed in the flow of the fluid flowing through the tube flow path 12.

  The vortex detector 26 and its lead wire 27 are fixed and fixed in a potting manner by a molding material 33 filled in an insertion guide hole 22A formed in the center of the base portion 22. The vortex detector 26 detects the vortex generated in the tube flow path 12 by the vortex generator 15, converts it into an electric quantity, and outputs it.

  A circumferential groove 28 is formed on the inner circumferential surface of the insertion guide hole 22 </ b> A of the base 22, and the molding material 33 is also filled in the circumferential groove 28. As a result, the ring-shaped protrusion 29 is formed by the molding material 33 in the circumferential groove 28. The pulling strength of the molding material 33 is improved by the engagement between the ring-shaped protrusion 29 and the circumferential groove 28.

  Further, since the circumferential groove 28 is close to the opening end of the insertion guide hole 22A, the ring 33 can be ring in a short time in the phenomenon that the molding material 33 is cured from the surface (the ultraviolet curable bond is cured from the surface irradiated with ultraviolet rays). The ridge portion 29 is cured, and the lead time can be shortened.

  As shown in FIG. 6, key-shaped protrusions 30 for circumferential alignment are formed in the radial direction of the base portion 22 at locations on the outer peripheral surface that are rotationally displaced by 180 degrees in the circumferential direction of the base portion 22. Has been. The protrusion 30 is engaged with the slit 20 of the vortex detecting member holding cylinder 16 as shown in FIGS. By this engagement, the mounting position in the circumferential direction of the vortex detecting member 21 with respect to the measuring instrument main body 11 is determined. Thereby, the thin wall side of the sheath part 24 is always set to a normal mounting posture along the main stream line direction of the pipe flow path 12.

  As shown in FIG. 4, the axial dimension of the base portion 22 of the vortex detection member 21 is larger than the depth dimension of the vortex detection member holding cylinder portion 16, and the upper end surface 22B of the base portion 22 is the vortex detection member holding cylinder portion 16. The upper end surfaces 16A and 22B form an annular right-angled corner 31.

  This right-angled corner portion 31 is resin-welded (resin welded portion 32) by fillet welding over the entire circumference. The vortex detecting member 21 is rigidly secured (fixed) to the measuring instrument main body 11 by the resin welded portion 32.

  7A to 7C show the resin welding process of the right-angled corner portion 31. FIG. As shown in FIG. 7A, a resin welding rod 50 made of a fluororesin is wound around the entire circumference of the right-angled corner portion 31. In this case, fillet welding is performed, and the welding points are two points indicated by symbols D and E. Hot air is blown onto the welded portion by the heater 51 to heat the resin welding rod 50 to the melting point or higher.

  When the surface of the resin welding rod 50 is melted to some extent, as shown in FIG. 7B, the resin welding rod 50 is brought into close contact with the welding surface of the right angle corner portion 31 using the pressing member 52. Press on. Thereby, as shown in FIG.7 (c), the resin welding part 32 is completed. Since the resin welded portion 32 is fillet welded, it is possible to obtain a higher weld strength than butt welding.

  In addition, as shown in FIG. 2, the welding strength can be further increased by resin welding (resin welding portion 34) of the engagement portion between the slit 20 and the protrusion 30. A highly reliable double seal can be obtained by welding the entire engaging portion. However, when used under conditions where the fluid temperature changes, the air layer between the double seals will thermally expand and pressure accumulation will occur, so the entire surface is not welded and the slit is not welded. It is good also as an air escape hole.

  As described above, according to this embodiment, the ring-shaped protrusion 25 is the circumferential groove 19 at the fitting portion between the vortex detecting member mounting hole 18 of the measuring instrument main body 11 and the fitting portion 23 of the vortex detecting member 21. By being fitted in an elastically deformed state, a hermetic seal is performed. Separately, the vortex detecting member holding cylinder 16 of the measuring instrument main body 11 and the base 22 of the vortex detecting member 21 are detected by the resin welding portion 32. Since the member 21 is fixed to the measuring instrument main body 11, a sufficient hermetic seal can be performed, and the mounting strength of the vortex detecting member can be sufficiently secured.

  FIG. 8 shows another embodiment of the vortex flowmeter according to the present invention. 8, parts corresponding to those in FIG. 4 are denoted by the same reference numerals as those in FIG. 4, and description thereof is omitted.

  In this embodiment, the vortex detecting member 21 is pushed out into the measuring instrument main body 11 by a cap nut-like cap member 36 screwed to the outer periphery of the vortex detecting member holding cylinder 16 of the measuring instrument main body 11 by the screw portion 35. Stopped and fixed.

  In the fixing by the cap nut-like cap member 36, the vortex detecting member 21 can be reliably fixed to the measuring instrument main body 11 without using a plurality of bolts or tools.

  In this embodiment, the outer diameter of the fitting portion 23 of the vortex detecting member 21 is slightly larger than the outer diameter of the vortex detecting member mounting hole 18. As a result, when the fitting portion 23 is fitted and inserted into the vortex detecting member mounting hole 18, the entire fitting portion 23 is elastically deformed, and an airtight seal with a face seal is performed.

  This hermetic sealing is also surely performed in a close contact state obtained by elastic deformation of the fitting portion 23 made of fluororesin rich in elasticity and the measuring instrument main body 11.

  Further, as shown in FIG. 9, the check claw 37 provided on the cap member 38 is engaged with the engaging portion 39 formed on the measuring instrument main body 11 so as to protrude from the inner surface of the cap member 38. The vortex detecting member 21 may be fixed to the measuring instrument main body 11 in a pressing manner by pressing the provided pressing member 40 against the upper end surface 22B of the base portion 22.

  Even when the cap member 38 with the check pawl is fixed, the vortex detecting member 21 can be securely fixed to the measuring instrument main body 11 without using a plurality of bolts or tools.

Ancillary features of the airtight seal structure of the vortex detecting member in the vortex flowmeter according to the present invention are as follows.
(1) The measuring instrument main body and the vortex detection member are both made of fluororesin, and a ring-shaped protrusion having an outer diameter larger than the inner diameter of the vortex detection member mounting hole on the outer peripheral surface of the fitting portion of the vortex detection member. A ring portion, and the vortex detecting member is inserted into the vortex detecting member mounting hole from the outside of the measuring instrument main body, and the fitting portion is fitted into the vortex detecting member mounting hole, whereby the ring shape The protrusion is elastically deformed, and an airtight seal is provided between the vortex detecting member mounting hole and the fitting portion.

It is a side view which shows one embodiment of the vortex flowmeter by this invention. It is a top view (CC sectional view taken on the line of FIG. 3) showing one embodiment of the vortex flowmeter according to the present invention. It is the sectional view on the AA line of FIG. It is sectional drawing along the BB line of FIG. It is a half sectional view showing a single vortex detection member used in a vortex flowmeter according to one embodiment. It is a bottom view which shows the vortex detection member single-piece | unit used with the vortex flowmeter by one Embodiment. (A)-(c) is process drawing which shows the resin welding process of a measuring device main body and a vortex detection member. It is sectional drawing which shows other embodiment of the vortex flowmeter by this invention. It is sectional drawing which shows other embodiment of the vortex flowmeter by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Measuring instrument main body 12 Pipe flow path 15 Vortex generator 16 Vortex detection member holding | maintenance cylinder part 18 Vortex detection member attachment hole 19 Circumferential groove 20 Slit 21 Vortex detection member 22 Base 23 Fitting part 24 Sheath part 25 Ring-shaped protrusion 26 Vortex detector 32 Resin welded part 33 Mold material 34 Resin welded part 35 Screw part 36 Cap member 37 Check claw 38 Cap member 50 Resin welding rod

Claims (5)

A tube flow path is formed inside the measuring instrument body, and the vortex generated by the vortex generator provided in the tube flow path is detected by a vortex detector built in the vortex detecting member attached to the measuring instrument body. In the vortex flowmeter that
The measuring instrument main body communicates with the vortex detecting member holding cylinder portion formed on the outer surface of the measuring instrument main body, the vortex detecting member holding cylinder portion and the pipe flow path through the measuring instrument main body. A vortex detection member mounting hole is formed,
The vortex detection member includes a base portion that is fitted to the vortex detection member holding cylinder portion, a fitting portion that is fitted to the vortex detection member mounting hole and performs an airtight seal, and the vortex detector is incorporated in the tube. A sheath portion disposed in the flow path,
The vortex detection member holding cylinder and the base of the vortex detection member are resin welded,
Vortex flowmeter characterized by that.   The axial dimension of the base of the vortex detection member and the depth dimension of the vortex detection member holding cylinder are formed with different lengths, and the base is fitted to the vortex detection member holding cylinder. Any one of the base portion and the vortex detection member holding cylinder portion protrudes from the other, and the one and the other form an annular right angle corner, and the resin welding is performed on the entire circumference of the right angle corner. The vortex flowmeter according to claim 1, wherein the vortex flowmeter is formed by fillet welding. A tube flow path is formed inside the measuring instrument body, and the vortex generated by the vortex generator provided in the tube flow path is detected by a vortex detector built in the vortex detecting member attached to the measuring instrument body. In the vortex flowmeter that
The measuring instrument main body communicates with the vortex detecting member holding cylinder portion formed on the outer surface of the measuring instrument main body, the vortex detecting member holding cylinder portion and the pipe flow path through the measuring instrument main body. A vortex detection member mounting hole is formed,
The vortex detection member includes a base portion that is fitted to the vortex detection member holding cylinder portion, a fitting portion that is fitted to the vortex detection member mounting hole and performs an airtight seal, and the vortex detector is incorporated in the tube. A sheath disposed in the flow path,
A vortex flowmeter, wherein the vortex detecting member is fixed to the measuring instrument main body by a cap nut-like cap member screwed to the vortex detecting member holding cylinder portion. A tube flow path is formed inside the measuring instrument body, and the vortex generated by the vortex generator provided in the tube flow path is detected by a vortex detector built in the vortex detecting member attached to the measuring instrument body. In the vortex flowmeter that
The measuring instrument main body communicates with the vortex detecting member holding cylinder portion formed on the outer surface of the measuring instrument main body, the vortex detecting member holding cylinder portion and the pipe flow path through the measuring instrument main body. A vortex detection member mounting hole is formed,
The vortex detection member includes a base portion that is fitted to the vortex detection member holding cylinder portion, a fitting portion that is fitted to the vortex detection member mounting hole and performs an airtight seal, and the vortex detector is incorporated in the tube. A sheath portion disposed in the flow path,
The vortex flowmeter is characterized in that the vortex detecting member is fixed to the measuring instrument main body by a cap member with a non-returning claw that is non-reversely engaged with the measuring instrument main body.   Both the vortex detecting member mounting hole and the fitting portion have a circular cross-sectional shape, and are engaged with the vortex detecting member holding cylinder portion and the base portion of the vortex detecting member to each other to the measuring instrument main body. A concave / convex engaging portion for defining a circumferential mounting position of the vortex detecting member is provided, and the concave / convex engaging portions engage with each other by insertion of the vortex detecting member into the vortex detecting member mounting hole. The vortex flowmeter according to any one of claims 1 to 4.

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