JP4313121B2 - Flow meter case and case molding method - Google Patents

Description

The present invention relates to a flow meter case and a case forming method, and more particularly, to a flow meter case and a case forming method using a resin molded product having a joint connecting tube portion on a case body.

  As a case of a flow meter such as a vortex flow meter, there is a case of a resin molded product in which a pipe flow path for measuring a flow rate is formed in the case body (for example, Patent Document 1).

  In the case described above, as one pipe connection specification, a resin tube for joint connection having a shaft length necessary for mounting the joint assembly is welded or welded to the inlet port or outlet port opened in the outer wall of the case body. In some cases, a joint assembly for connecting pipes may be attached to the resin tube.

  The joint assembly for pipe connection includes an inner sleeve having a seal surface portion that is press-fitted into the inner diameter portion of the resin tube and tightly adheres to the inner peripheral surface of the tube, a cap nut provided on the outer periphery of the resin tube, and a resin There is an inner / outer fitting type with a joint body including a tube portion having a seal surface portion that is fixed to the outer diameter portion of the tube by screw tightening with a cap nut and tightly adheres to the outer peripheral surface of the tube.

  When such an inner / outer fitting type joint assembly is used, since there is a tight seal portion on both the inner and outer peripheral surfaces of the resin tube, the inner peripheral surface and the outer peripheral surface of the resin tube are provided on either peripheral surface. However, it is not preferable that a flash, a step, or the like that inhibits the tight seal performance is present. The flash, the step, or the like causes leakage due to a seal failure, and decreases the stability and reliability of the tight seal.

  On the other hand, when the resin tube is molded by a mold that is split in the radial direction, such as the upper half and the lower half, a parting line that is split on the outer peripheral surface of the resin tube is inevitably generated. In addition, the outer peripheral surface of the resin tube has a step that hinders the tight sealability and has a step.

Further, in the case where the resin tube is welded and welded to the case body, it is necessary to ensure and confirm the strength and airtightness of the welded portion of the resin tube, the welded portion, and it takes time.
JP 2000-321102 A

The problem to be solved by the present invention is that, in the case of a flow meter , there is a flash, a step, or the like that inhibits tight sealability on any of the inner and outer peripheral surfaces of the joint connecting tube. Without using the inner fitting type, the outer fitting type, the inner / outer fitting type joint assembly, it is possible to perform a tight seal with excellent stability and reliability, and also to weld and weld the resin tube to the case body. An object of the present invention is to provide a flow meter case and a method for forming the case that can improve reliability without the need.

A flow meter case according to the present invention is connected to a case main body for a flow meter in which a pipe flow path for measuring a flow rate is formed , and an inlet port or an outlet port opened in an outer wall of the case main body, and a joint assembly is attached. It has a shaft length required, and an inner diameter passage and a tube portion for fitting connections provided in communication with the said tube flow path, and the case body by the injection of the molten resin to the mold cavity The joint connecting tube portion is integrally formed, and the tube portion is provided so that an axial direction thereof is perpendicular to a separating direction of the upper and lower molds forming the case main body, and the joint assembly is formed of the tube portion. a case of flow meter is provided with a sealing surface on the inner peripheral surface and outer peripheral surface in close contact with the airtight respectively, wherein the inner circumferential surface of the tube portion and the outer peripheral surface are both either said case body Wherein Ri Do from the molding surface which is molded by an integral of the slide core die which toward the end face side of the tube portion is stamped in the axial direction, the slide core type, cylinder for the outer circumference forming the tube portion -Shaped outer diameter slide core mold and a rod-shaped inner diameter slide core concentrically arranged inside the outer diameter slide core mold and integrally formed with the outer diameter slide core mold It has a mold .

In the case of a flowmeter according to the present invention, as the pre-Symbol tube section, for each side respectively communicated with by the tube portion and the inlet-side connection of the inlet side connected to the inlet and outlet ports which open respectively to the outer wall of the case body The tube portion for outlet side connection molded to the same diameter as the tube portion of the tube is integrally molded, and the inner peripheral surface and the outer peripheral surface of the tube portion for inlet side connection and the tube portion for outlet side connection are Are formed by integral slide core dies that are respectively cut in the axial direction from the case main body side toward the end face side of the inlet side connecting tube portion and the outlet side connecting tube portion. It consists of a molded surface.

The flow meter case forming method according to the present invention is a case forming method for a flow meter according to claim 1, wherein molten resin is injected into a cavity of the forming die, and the case main body is divided into upper and lower parts as the forming die. An upper mold and a lower mold, a cylindrical outer diameter slide core mold for forming the outer diameter of the tube portion, and the outer diameter slide core disposed concentrically inside the outer diameter slide core mold. The outer diameter slide core mold and the inner diameter slide core mold are connected to the end surface of the tube portion from the case main body side using a rod-shaped inner diameter slide core mold for inner diameter molding that is integrated with the mold. The inner peripheral surface and the outer peripheral surface of the tube part are formed by die-cutting in the axial direction of the tube part orthogonal to the separation direction of the upper mold and the lower mold toward the side.

According to the case of the flow meter and the case forming method according to the present invention, the inner slide and the outer peripheral surface of the tube portion are both integrally slided in the axial direction from the case main body side toward the end surface side of the tube portion. It consists of a molding surface molded by the core mold, and there is no parting line of the molding die on either the inner peripheral surface or the outer peripheral surface of the tube part for joint connection. There are no flashes or steps that impede tight sealability on any of the peripheral surfaces, and stability and reliability are ensured when using an inner fitting type, outer fitting type, and inner / outer fitting type joint assembly. It is possible to obtain a close-sealing property with excellent properties.

  In addition, since the tube portion is integrally formed with the case main body, there is no welding or welding of the resin tube to the case main body, the strength and reliability are improved, and the cost can be reduced.

FIG. 1 shows one embodiment in which a case of a flow meter according to the present invention is applied to a vortex flow meter.

  The vortex flowmeter has a case 11 made of a resin molded product made of fluororesin or the like. The case 11 includes a box-shaped case main body 12 and a cover 23. On both sides of the case main body 12, a tube portion 13 for inlet side connection and a tube portion 14 for outlet side connection are integrally formed as joint connecting tube portions.

  A tube flow path 15 for measuring a flow rate is formed in the case body 12. One side (left side in the figure) of the pipe flow path 15 communicates with the inner diameter passage 16 of the tube part 13 for inlet side connection, and the other side (right side in the figure) shows the inner diameter of the tube part 14 for outlet side connection. It communicates with the passage 17.

  A positioning fitting portion 18 is formed in the case body 12. A detector holding block 19 is fitted to the positioning fitting portion 18. A columnar vortex generator 20 and a vortex detector 21 are integrally formed in the detector holding block 19.

  The vortex generator 20 extends across the pipe flow path 15 in the vertical direction. The vortex detector 21 is located in the pipe flow path 15 on the downstream side of the vortex generator 20 and incorporates a vortex detector 22. The vortex detector 22 is constituted by a pressure / electric conversion element (piezoelectric element) or the like, and the vortex in the tube flow path 15 is located at a position downstream of the vortex generator 20 as viewed in the flow of the fluid flowing in the tube flow path 15. Detection is performed and an electric signal corresponding to the vortex detection value is output.

  A cover 23 is attached to the upper side of the case body 12, and the cover 23 defines an electric box chamber 24 inside. The electrical box chamber 24 is provided with electrical parts 25 for measuring instruments, wirings 26 and the like.

  The tube portion 13 for connection on the inlet side and the tube portion 14 for connection on the outlet side are formed on both the inner peripheral surfaces 13A and 14A and the outer peripheral surfaces 13B and 14B by a slide core die cut in the axial direction. The parting line is formed without a parting line. The inlet-side connecting tube portion 13 and the outlet-side connecting tube portion 14 each have an axial length L (see FIG. 2) necessary to attach the joint assembly 30. This axial length L may be about three times the tube outer diameter d (see FIG. 2).

  The inner sleeve 31 of the joint assembly 30 is press-fitted into the tube portion 13 for connection on the inlet side and the tube portion 14 for connection on the outlet side. Each inner sleeve 31 is a resin molded product made of fluororesin or the like, and has a tapered seal surface portion 32 that is airtightly adhered to the tube inner peripheral surfaces 13A and 14A. A cap nut 33 is provided on the outer periphery of each tube portion 13, 14. In addition, a joint body 34 is fitted and fixed to each tube portion 13 and 14 by screwing with a cap nut 33. Each joint body 34 is a resin molded product made of a fluororesin or the like, and has a seal surface portion 35 that is airtightly adhered to the tube outer peripheral surfaces 13B and 14B.

  FIG. 2 shows the case 11 as a single molded product before the inner sleeve 31 is press-fitted, and the tube portions 13 and 14 have a straight shape that can be punched in the axial direction.

  As described above, the inner peripheral surface 13A and the outer peripheral surface 13B of the tube portion 13 for connection on the inlet side and the inner peripheral surface 14A and the outer peripheral surface 14B of the tube portion 14 for connection on the outlet side are both formed of a mold. Since there is no parting line, any of the inner peripheral surfaces 13A and 14A and the outer peripheral surfaces 13B and 14B of the tube portions 13 and 14 has a flash that inhibits the tight sealability of the seal surface portions 32 and 35. Further, there is no step and the like, and in the use of the joint assembly 30 of the inside / outside fitting type, it is possible to obtain a tight seal property excellent in stability and reliability.

  In addition, since both the inlet-side connecting tube portion 13 and the outlet-side connecting tube portion 14 are formed integrally with the case main body 12, there is no welding or welding of the resin tube to the case main body 12, and the strength and reliability. And the work of ensuring and confirming the strength and airtightness of the welded and welded parts of the resin tube is not required.

Next, a method for forming the case 11 will be described with reference to FIGS. As shown in FIG. 3, the molding of the casing 11, have a cavity 50 for molding the casing body 12 portion or the like, the upper mold that will be opened mold separation direction indicated by the arrow (fixed) 51 and the lower die and (movable mold) 52, tubing outer circumference forming a cylindrical outer diameter contouring slide core mold 53 and, being concentrically disposed within the outer diameter contouring slide core die 53, 54 the outer diameter contouring The tube portion 13 is configured integrally with the slide core dies 53 and 54 and is orthogonal to the separation direction of the upper die 51 and the lower die 52 from the case body 12 side toward the end surfaces of the tube portions 13 and 14 as indicated by arrows. , 14 are used together with rod-shaped inner diameter slide core dies 55 and 56 for tube inner diameter forming which are die-cut together with outer diameter slide core dies 53 and 54 in the axial direction. The molten resin is injected into the cavity 50 from the gate 51 </ b> A provided in the upper mold 51.

  As shown in FIG. 4, the lower mold 52 is opened by moving downward in the figure, and the outer diameter slide core mold 53 and the inner diameter slide core mold 55 are on the left side in the figure. The outer diameter slide core die 54 and the inner diameter slide core die 56 are die cut by moving to the right in the drawing.

  Thereby, in the case main body 12 part, the parting line P by the upper die 51 and the lower die 52 is formed, but the inner peripheral surface 13A and the outer peripheral surface 13B of the tube portion 13 for inlet side connection, and the outlet side connection. There is no parting line for the mold on either the inner peripheral surface 14A or the outer peripheral surface 13B of the tube portion 14. Thereby, the tube parts 13 and 14 for inlet side connection and outlet side connection are shape | molded without a parting line.

  As described above, there is no parting line of the molding die on each of the inner peripheral surfaces 13A and 14A and the outer peripheral surfaces 13B and 14B of the tube portion 13 for inlet side connection and the tube portion 14 for outlet side connection. From the inner peripheral surfaces 13A and 14A and the outer peripheral surfaces 13B and 14B of the tube portions 13 and 14, there are flashes, steps, and the like that inhibit the tight sealing performance of the seal surface portions 32 and 35. There is nothing.

  Thereby, in the use of the joint assembly 30 of the inside / outside fitting type, it is possible to obtain a tight seal property excellent in stability and reliability, and no leakage occurs in the joint assembly 30 portion.

  The outer diameter slide core dies 53 and 54 and the inner diameter slide core dies 55 and 56 may be integrally formed as shown in FIG. 4, or are shown in FIG. In this manner, the outer diameter slide core molds 53 and 54 and the inner diameter slide core molds 55 and 56 may be formed separately and used in combination.

Sectional drawing which shows one Embodiment which applied the case of the flowmeter by this invention to the vortex flowmeter. It is a front view of the case and cover of FIG. It is a figure which shows one Embodiment of the shaping | molding die used with the case shaping | molding method of the flowmeter by this invention. It is a figure which shows the mold open state in the case shaping | molding method of the flowmeter by this invention. It is a principal part expanded sectional view which shows another embodiment of the slide core type | mold of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Case 12 Case main body 13 Tube part for inlet side connection 14 Tube part for outlet side connection 20 Vortex generator 25 Vortex detector 30 Joint assembly 31 Inner sleeve 33 Cap nut 34 Joint body 51 Upper mold 52 Lower mold 53 54 Slide core type for outer diameter 55, 56 Slide core type for inner diameter

Claims (3)

A case body of the flowmeter formed a tube passage of performing flow rate measurement, in communication with the inlet port or an outlet port opened to the outer wall of the case body have a shaft length for installing coupling assembly And a joint connecting tube portion provided in communication with the pipe flow path, and the case main body and the joint connecting tube portion are formed by injecting molten resin into the cavity of the mold. The tube portion is integrally formed, and the tube portion is provided so that the axial direction thereof is orthogonal to the separating direction of the upper and lower molds forming the case body, and the joint assembly is airtight on the inner peripheral surface and the outer peripheral surface of the tube portion A flow meter case having a sealing surface part closely contacting with
Both the inner peripheral surface and the outer peripheral surface of the tube portion are formed by an integral slide core die that is die-cut in the axial direction from the case body side toward the end surface side of the tube portion. Tona is,
The slide core mold is a cylindrical outer diameter slide core mold for forming the outer diameter of the tube portion, and the outer diameter slide core mold is disposed concentrically inside the outer diameter slide core mold. A flow meter case comprising a rod-shaped inner diameter slide core mold for inner diameter molding that is formed integrally with the inner diameter . As before Symbol tube section, it is formed on both sides in the same diameter as the tube portion of the respective outer wall in communication with each of the opened inlet port and an outlet port inlet side tube portion for connection and for the inlet-side connection of the case body The tube section for connecting the outlet side is integrally molded,
Both the inner peripheral surface and the outer peripheral surface of the inlet-side connection tube portion and the outlet-side connection tube portion are connected to the inlet-side connection tube portion and the outlet-side connection from the case body side. The case of the flowmeter according to claim 1, comprising a molding surface formed by an integral slide core die that is die-cut in the axial direction toward the end face side of the tube portion. The method of molding a flow meter case according to claim 1, wherein molten resin is injected into the cavity of the mold.
As the forming mold, an upper mold and a lower mold for forming the case main body which are separated into upper and lower parts, a cylindrical outer diameter slide core mold for forming the outer diameter of the tube portion, and the outer diameter slide core mold The outer diameter slide core mold and the inner diameter slide are formed using a rod-shaped inner diameter slide core mold for inner diameter molding that is concentrically disposed inside and integrally configured with the outer diameter slide core mold. A core mold is punched in the axial direction of the tube section perpendicular to the separation direction of the upper mold and the lower mold from the case body side toward the end face side of the tube section, and the inner peripheral surface of the tube section A method for forming a case of a flowmeter, comprising forming the outer peripheral surface.

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