CN108955786B

CN108955786B - Flow meter

Info

Publication number: CN108955786B
Application number: CN201710371363.XA
Authority: CN
Inventors: 都筑元吾; 伊藤久生
Original assignee: Aichi Tokei Denki Co Ltd
Current assignee: Aichi Tokei Denki Co Ltd
Priority date: 2017-05-23
Filing date: 2017-05-23
Publication date: 2021-08-10
Anticipated expiration: 2037-05-23
Also published as: CN108955786A

Abstract

The invention aims to provide a flowmeter which can restrain the position deviation of a measuring unit which is detachably arranged on a cylindrical main body. A flow meter (10) of the present invention comprises: a tubular main body (11) having an inner tubular flow path (13) therein and connected to a middle of the pipe (90); a fitting hole (20) extending radially outward from the tubular flow path (13) and opening at the side of the tubular body (11); and a measurement unit (30) detachably attached to the attachment hole (20). The measurement unit (30) has: a shaft portion (40) that passes through the attachment hole (20) and extends into the cylindrical flow path (13); a shaft through hole (40A) that penetrates the shaft section (40) in the axial direction of the tubular body (11); and a measuring unit (50) for measuring the flow rate of the fluid flowing through the shaft through hole (40A). The fitting holes (20) are provided in pairs so as to face each other in the radial direction of the tubular body (11), and the shaft portion (40) bridges the portion of the tubular body (11) where the pair of fitting holes (20, 20) are formed.

Description

Flow meter

Technical Field

The present invention relates to a flowmeter in which a measurement unit is attached to a tubular main body connected to a middle of a pipe.

Background

As such a flow meter, the following flow meters have been known: the measurement means is supported by the tubular main body in a cantilever shape in a state of being inserted through a fitting hole penetrating a tubular wall of the tubular main body, and measures a flow rate of the fluid by a portion of the measurement means which extends into the tubular main body (for example, see patent document 1).

Prior art documents

Patent document

Patent document 1: japanese Kokai publication Sho-63-163417 (page 4, line 18 to page 5, line 11, FIG. 1)

Disclosure of Invention

Problems to be solved by the invention

However, in order to enable replacement of the measurement unit, it is conceivable to detachably attach the measurement unit to the tubular main body. However, in the above-described conventional flow meter, since the measurement unit is supported in a cantilever shape, the measurement unit is pressed outward of the tubular body by the fluid pressure in the tubular body, which causes a problem of positional displacement of the measurement unit. Further, when the amount of displacement of the measurement unit is large, the measurement unit may be detached from the tubular main body.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a flow meter capable of suppressing positional displacement of a measurement unit detachably attached to a tubular main body.

Means for solving the problems

The flowmeter according to the present invention, which has been completed to achieve the above object, includes: a tubular main body connected to a middle of a pipe and having an inner tubular flow path inside which a fluid flowing through the pipe can pass; a fitting hole extending radially outward from the tube inner flow path and opening at a side portion of the tubular main body; and a measurement unit that is detachably attached to the attachment hole and measures a flow rate of the fluid, wherein the measurement unit includes: a shaft portion that passes through the fitting hole and that extends into the tube inner flow path; a shaft through hole that penetrates a portion of the shaft portion that protrudes into the flow path in the cylinder in an axial direction of the cylindrical body; and a measuring portion that measures a flow rate of the fluid flowing through the shaft through-hole, wherein the mounting holes are provided in pairs so as to face each other in a radial direction of the cylindrical body, and the shaft portion is bridged over a portion of the cylindrical body where the pair of mounting holes are formed and passes through both of the pair of mounting holes.

Drawings

Fig. 1 is a side sectional view of a flow meter according to an embodiment of the present invention.

Fig. 2 is an enlarged view of the periphery of the measurement unit in fig. 1.

Fig. 3 is a cross-sectional elevation view of the flow meter.

Fig. 4 is an exploded perspective view of the flow meter.

Fig. 5 (a) is a side sectional view of the shaft portion, and fig. 5 (B) is a side sectional view of the large-diameter hole and the small-diameter hole.

Fig. 6 is a side sectional view of the measurement unit and the tubular body before the shaft portion passes through the large-diameter hole.

Fig. 7 is a side sectional view of the measurement unit and the tubular body before the shaft portion passes through the small diameter hole.

Fig. 8 is a side sectional view of the periphery of a measurement unit of a flowmeter according to another embodiment.

Description of reference numerals:

10: a flow meter; 11: a cylindrical main body; 13: a flow path in the barrel; 20: an assembly hole; 21: a large-diameter hole; 21A: an outer expanded portion (large diameter expanded portion); 22: a small-diameter hole; 22B: an inner expanded portion (small diameter expanded portion); 30: a measurement unit; 40: a shaft portion; 41: a large diameter portion; 43: a small diameter part; 45A: a large-diameter seal member; 45B: a small-diameter seal member; 50: a measurement unit; 90: piping.

Detailed Description

An embodiment in which the present invention is applied to an electromagnetic flowmeter will be described below with reference to fig. 1 to 7. As shown in fig. 1, in the flow meter 10 of the present embodiment, the axial intermediate portion of the tubular body 11 is covered on the outside by the case portion 60, and the measurement unit 30 is housed in the case portion 60.

The tubular main body 11 is connected to a middle portion of the pipe 90, and an in-cylinder flow path 13 through which a fluid flowing through the pipe 90 can pass is formed inside the cylinder wall 12 of the tubular main body 11. Further, a fitting hole 20 extending radially outward from the in-cylinder flow passage 13 and opening to a side portion of the cylindrical body 11 is formed in an axial intermediate portion of the cylindrical body 11. Specifically, the tubular body 11 is provided with a manifold 14 projecting radially outward from an intermediate portion in the axial direction of the tubular wall 12, and the fitting hole 20 is formed in an inner portion of the manifold 14 (see fig. 4 and 5B. it is noted that flanges 11F connected to the flanges 90F of the pipes 90 are formed at both end portions in the axial direction of the tubular body 11.

The case portion 60 has a box shape and has tubular

body accommodating holes

60A, 60A for accommodating the tubular wall 12 of the tubular body 11. Specifically, as shown in fig. 1 and 4, the case portion 60 can be divided into an upper case 61 having an open bottom and a lower case 62 having an open top. The pair of

opposing side walls

62S, 62S of the lower case 62, which are disposed to face each other in the axial direction of the tubular body 11, have

notches

62K, 62K formed therein, which extend downward from the upper end of the lower case 62. The bottom opening of the upper case 61 is one larger than the upper opening of the lower case 62. When the upper case 61 and the lower case 62 are coupled, the side wall 61S of the upper case 61 is overlapped with the upper end portion of the cutout portion 62K of the lower case 62 to form the cylindrical body accommodating hole 60A.

As shown in fig. 2 and 4, the measurement unit 30 has a substantially T-shape in a side view in which the leg portion 30B is suspended from the lower surface of the cassette portion 30A. Specifically, the measurement unit 30 is formed by connecting a shaft portion 40 disposed below a middle position of the leg portion 30B to a legged head portion 31 disposed above the middle position.

As shown in fig. 2, the shaft portion 40 is inserted through the fitting hole 20 of the tubular body 11, and the legged head portion 31 is disposed outside the tubular body 11. An annular groove 40M is formed in the outer peripheral portion of the shaft portion 40, and a seal member 45 fitted in the annular groove 40M seals a gap between the shaft portion 40 and the attachment hole 20.

A part of the shaft portion 40 extends into the in-cylinder flow path 13, and a shaft through hole 40A extending in the axial direction of the tubular body 11 is formed in the extending portion. The fluid in the in-cylinder flow path 13 flows through the shaft through hole 40A.

As shown in fig. 3, the shaft portion 40 incorporates a measurement portion 50 that measures the flow rate of the fluid flowing through the shaft through hole 40A. Specifically, the measurement unit 50 includes a core 51 around which a coil 52 is wound, a pair of detection electrodes 53, and a voltmeter (not shown) that measures a voltage between the pair of

detection electrodes

53, 53. The core 51 has a substantially U shape, and is disposed so as to sandwich the shaft through hole 40A in, for example, the horizontal direction by both end portions. The pair of

detection electrodes

53, 53 are disposed so as to sandwich the shaft through hole 40A in the vertical direction, for example. An opening 53A for exposing each detection electrode 53 is formed in the inner peripheral surface of the shaft through hole 40A, and the pair of

detection electrodes

53, 53 are brought into contact with the fluid flowing inside the shaft through hole 40A. When the fluid flows through the shaft through-hole 40A with the coil 52 energized, a potential difference corresponding to the flow velocity of the fluid is generated between the pair of

detection electrodes

53 and 53, and the potential difference is measured by a voltmeter, not shown.

The legged head 31 (see fig. 4) includes an arithmetic unit (not shown) for calculating the flow rate of the fluid flowing through the shaft through hole 40A based on the measurement result of the measurement unit 50 (i.e., the flow velocity of the fluid flowing through the shaft through hole 40A). The legged head 31 is provided with, for example, a display unit for displaying the calculation result of the calculation unit, a transmission unit for wirelessly transmitting the calculation result to the outside, and the like.

Here, in the flow meter 10 of the present embodiment, the mounting holes 20 are provided in pairs so as to face each other in the radial direction of the tubular body 11. The shaft portion 40 of the measurement unit 30 is disposed so as to bridge the portion of the tubular body 11 where the pair of

attachment holes

20 and 20, that is, the pair of

manifolds

14 and 14 are formed, and passes through the pair of

attachment holes

20 and 20. The annular grooves 40M are provided in two portions, i.e., a distal end portion and a proximal end portion of the shaft portion 40, and the sealing members 45 fitted into the respective annular grooves 40M seal between the shaft portion 40 and the attachment hole 20. In a state where the shaft portion 40 is attached to the pair of

attachment holes

20 and 20, the shaft through hole 40A is arranged substantially coaxially with the central axis of the tubular body 11.

As described above, in the present embodiment, the pair of

attachment holes

20, 20 are provided in the tubular body 11 so as to face each other in the radial direction, and the shaft portion 40 of the measurement unit 30 is disposed across the portion of the tubular body 11 where the pair of

attachment holes

20, 20 are formed (i.e., the pair of manifolds 14, 14), so that the shaft portion 40 can be offset from the fluid pressure received by the fluid flowing through the in-tube flow path 13 in the facing direction of the pair of attachment holes 20, and the positional displacement of the measurement unit 30 can be suppressed.

However, as shown in fig. 4, the flowmeter 10 is formed by assembling the measurement unit 30 and the case 60 (i.e., the upper case 61 and the lower case 62) to the tubular body 11. Specifically, first, the shaft portion 40 of the measurement unit 30 is inserted from the outside of the tubular body 11 into one of the pair of attachment holes 20, 20 (see fig. 6). After the shaft 40 is inserted through one of the attachment holes 20, the shaft 40 is further inserted, and the tip end portion of the shaft 40 is inserted into the other attachment hole 20 (see fig. 7). When the shaft portion 40 passes through both of the pair of attachment holes 20, the middle portion of the tubular body 11 is then sandwiched vertically by the upper case 61 and the lower case 62, and the upper case 61 and the lower case 62 are joined to accommodate the measurement unit 30 in the case portion 60. Thereby, the flowmeter 10 shown in fig. 1 is completed.

Here, if the pair of

mounting holes

20 and 20 are the same size (in this case, both end portions of the shaft portion 40 are also the same size), a situation may occur in which it is difficult to pass the shaft portion 40 through the mounting hole 20. When the shaft portion 40 is inserted through one of the mounting holes 20, the sealing member 45 for sealing the other mounting hole 20 may be damaged by collision or friction with the manifold 14 or may be separated from the annular groove 40M, thereby deteriorating the sealing property between the shaft portion 40 and the mounting hole 20. In order to prevent such a situation, the flow meter 10 of the present embodiment is provided with the configuration described below.

That is, as shown in fig. 5 (a), the shaft portion 40 has a structure in which the diameter is reduced on the side away from the legged head portion 31 at the intermediate portion in the axial direction, and includes a large diameter portion 41, a reduced diameter portion 42, and a small diameter portion 43 arranged in parallel in the axial direction from the legged head portion 31 side. The annular groove 40M is formed in the large-diameter portion 41 and the small-diameter portion 43, and the pair of

seal members

45, 45 is composed of a large-diameter seal member 45A fitted into the annular groove 40M of the large-diameter portion 41 and a small-diameter seal member 45B fitted into the annular groove 40M of the small-diameter portion 43. The reduced diameter portion 42 is formed in a tapered shape that gradually reduces in diameter toward the small diameter portion 43. Specifically, the reduced diameter portion 42 is disposed on the large diameter portion 41 side with respect to the shaft through hole 40A, and at least half of the shaft portion 40 is constituted by the small diameter portion 43.

As shown in fig. 5 (B), the pair of attachment holes 20 and 20 includes a large-diameter hole 21 and a small-diameter hole 22 having different diameters. In a state where the measurement unit 30 is assembled to the tubular body 11, the large diameter portion 41 of the shaft portion 40 passes through the large diameter hole 21, and the small diameter portion 43 of the shaft portion 40 passes through the small diameter hole 22. Specifically, the inner diameter of the large diameter hole 21 is slightly larger than the outer diameter of the large diameter portion 41, and the large diameter hole 21 and the large diameter portion 41 are sealed by a large diameter seal member 45A. The inner diameter of the small-diameter hole 22 is slightly larger than the outer diameter of the small-diameter portion 43, and the small-diameter hole 22 and the small-diameter portion 43 are sealed by a small-diameter seal member 45B.

An outer expanded portion 21A, which is expanded in diameter as it goes to the outside of the tubular body 11, is formed in a portion of the inner peripheral surface of the large-diameter hole 21 that is close to the outside of the tubular body 11 (the side away from the in-tube flow path 13). Further, an inner expanding portion 21B, which is expanded in diameter toward the cylindrical inner flow path 13 side, is formed in a portion of the inner peripheral surface of the large-diameter hole 21 adjacent to the cylindrical inner flow path 13. In the example of the present embodiment, both the outer expanded portion 21A and the inner expanded portion 21B are formed in an R shape. The inner diameter of the large-diameter hole 21 is the smallest diameter of the large-diameter hole 21. 13

An inner expanding portion 22B that expands in diameter toward the tubular inner flow path 13 is formed in a portion of the inner peripheral surface of the small-diameter hole 22 adjacent to the tubular inner flow path 13. In the example of the present embodiment, the inner expanded portion 22B is formed in the same R-shape as the inner expanded portion 21B described above. Further, a portion of the small-diameter hole 22 adjacent to the outside of the tubular body 11 is formed in a straight shape. The inner diameter of the small-diameter hole 22 is the smallest diameter of the small-diameter hole 22.

As described above, in the flowmeter 10 of the present embodiment, the shaft portion 40 has the large diameter portion 41 and the small diameter portion 43, and the pair of attachment holes 20 and 20 includes the large diameter hole 21 through which the large diameter portion 41 passes and the small diameter hole 22 which is smaller in diameter than the large diameter hole 21 and through which the small diameter portion 43 passes, so that, as shown in fig. 6, by passing the shaft portion 40 through the pair of attachment holes 20 and 20 with the small diameter portion 43 as the tip, the shaft portion 40 can easily pass through the pair of attachment holes 20 and 20, and when the small diameter portion 43 passes through the large diameter hole 21, collision and friction between the manifold 14 constituting the large diameter hole 21 and the small diameter seal member 45B are suppressed, and damage and detachment of the small diameter seal member 45B are suppressed.

In the present embodiment, since the inner expanded portion 22B whose diameter is expanded toward the in-cylinder flow path 13 is formed in the inner peripheral surface of the small-diameter hole 22 at a portion adjacent to the in-cylinder flow path 13, when the small-diameter portion 43 of the shaft portion 40 having passed through the large-diameter hole 21 is passed through the small-diameter hole 22, the small-diameter portion 43 can be guided into the small-diameter hole 22 by the inner expanded portion 22B. In the present embodiment, since the outer expanded portion 21A that expands in diameter as it goes to the outside of the tubular body 11 is formed in the portion of the inner peripheral surface of the large diameter hole 21 that is adjacent to the outside of the tubular body 11, when the small diameter portion 43 of the shaft portion 40 is inserted into the large diameter hole 21, the small diameter portion 43 can be guided into the large diameter hole 21 by the outer expanded portion 21A, and when the large diameter portion 41 of the shaft portion 40 is inserted into the large diameter hole 21, the large diameter portion 41 can be guided into the large diameter hole 21 by the outer expanded portion 21A. In the present embodiment, the outer expanded portion 21A of the large-diameter hole 21 corresponds to the "large-diameter expanded portion" of the present invention, and the inner expanded portion 22B of the small-diameter hole 22 corresponds to the "small-diameter expanded portion" of the present invention.

The above description relates to the structure of the flow meter 10 of the present embodiment. Next, the operation and effect of the flow meter 10 will be described.

In the flowmeter 10 of the present embodiment, the pair of attachment holes 20, 20 that face each other in the radial direction are provided in the tubular body 11, and the shaft portion 40 of the measurement unit 30 passes through the pair of attachment holes 20, so that the fluid pressure received by the shaft portion 40 from the fluid flowing through the in-tube flow path 13 can be cancelled out in the direction in which the pair of attachment holes 20, 20 face each other, and the positional displacement of the measurement unit 30 can be suppressed.

Further, since the large diameter portion 41 and the small diameter portion 43 are formed in the shaft portion 40, and the pair of attachment holes 20 and 20 are constituted by the large diameter hole 21 and the small diameter hole 22, when the measurement unit 30 is assembled to the tubular body 11, the shaft portion 40 is inserted into the pair of attachment holes 20 and 20 with the small diameter portion 43 as a tip, and thus the shaft portion 40 can be easily inserted into the pair of attachment holes 20 and 20. Further, the manifold 14 constituting the large-diameter hole 21 is prevented from colliding with and rubbing against the small-diameter seal member 45B, and damage and detachment of the small-diameter seal member 45B are prevented.

Further, since the inner expanded portion 22B, which is expanded in diameter toward the in-cylinder flow path 13 side, is formed in the inner peripheral surface of the small-diameter hole 22 at a portion adjacent to the in-cylinder flow path 13, when the small-diameter portion 43 of the shaft portion 40 is inserted into the small-diameter hole 22, the small-diameter portion 43 can be guided into the small-diameter hole 22 by the inner expanded portion 22B. In the present embodiment, since the outer expanded portion 21A that expands in diameter as it goes to the outside of the tubular body 11 is formed in the inner peripheral surface of the large diameter hole 21 at a portion adjacent to the outside of the tubular body 11, the large diameter portion 41 and the small diameter portion 43 can be guided into the large diameter hole 21 by the outer expanded portion 21A when the large diameter portion 41 and the small diameter portion 43 of the shaft portion 40 are passed through the large diameter hole 21.

[ Another embodiment ]

The present invention is not limited to the above-described embodiments, and for example, the embodiments described below are also included in the technical scope of the present invention, and various modifications other than the following can be made without departing from the gist of the present invention.

(1) In the above-described embodiments, the present invention is applied to an electromagnetic flowmeter, but may be applied to a flowmeter other than an electromagnetic flowmeter such as an ultrasonic flowmeter or a thermal flowmeter.

(2) In the above embodiment, the outer expanded portion 21A of the large-diameter hole 21 and the inner expanded portion 22B of the small-diameter hole 22 are both R-shaped, but one or both may be tapered. That is, the outer expanded portion 21A may have a tapered shape whose diameter increases as going to the outer side of the tubular body 11, and the inner expanded portion 22B may have a tapered shape whose diameter increases as going to the in-cylinder flow path 13 side.

(3) In the above embodiment, the reduced diameter portion 42 of the shaft portion 40 is formed in a tapered shape, but may be formed in a stepped shape. In addition, according to the configuration of the above embodiment, the reduced diameter portion 42 can be easily inserted into the large diameter hole 21.

(4) In the above embodiment, the outer expanded portion 21A may not be provided on the inner peripheral surface of the large diameter hole 21. In this case, the small diameter portion 43 of the shaft portion 40 can be guided to the small diameter hole 22 by the inner expanded portion 22B of the small diameter hole 22.

(5) In the above embodiment, the pair of mounting

holes

20 and 20 may have the same diameter. In this case, if the expanded portion whose diameter is expanded toward the tubular inner flow path 13 is formed in the portion of the inner peripheral surface of one of the mounting holes 20 adjacent to the tubular inner flow path 13, the tip end portion of the shaft portion 40 can be guided to the one mounting hole 20, and the shaft portion 40 can be easily inserted into the one mounting hole 20, similarly to the inner expanded portion 22B of the above-described embodiment.

(6) In the above embodiment, the mounting

holes

20, 20 are formed by the

manifolds

14, 14 protruding from the cylindrical wall 12, but for example, as shown in fig. 8, the cylindrical wall 12 may have a thick wall, and the mounting

holes

20, 20 may be formed by the through

holes

12A, 12A penetrating the cylindrical wall 12. In this case, the cylindrical wall 12 may have a thickness over the entire axial range, or may have a thickness only in a portion where the measurement unit 30 is incorporated. In the example of fig. 8, the inner diameter of each through hole 12A is constant over the entire axial range, but the end portion of one through hole 12A facing the outside of the tubular body 11 may be expanded as it goes to the outside of the tubular body 11, and the end portion of the other through hole 12A on the side of the in-cylinder flow path 13 may be expanded as it goes to the side of the in-cylinder flow path 13.

(7) In the above embodiment, both end portions of the shaft portion 40 may be screwed into the pair of attachment holes 20, 20. Specifically, screw portions may be formed on the outer peripheral surfaces of both end portions of the shaft portion 40, and the pair of attachment holes 20, 20 may be screw holes. According to this configuration, the screw looseness caused by the fluid pressure received by the shaft portion 40 can be suppressed, and the positional displacement of the shaft portion 40 can be suppressed.

Claims

1. A flow meter, comprising:

a tubular main body connected to a middle of a pipe and having an inner tubular flow path inside which a fluid flowing through the pipe can pass;

a fitting hole extending radially outward from the tube inner flow path and opening at a side portion of the tubular main body; and

a measurement unit that is detachably attached to the attachment hole and measures a flow rate of the fluid,

wherein the content of the first and second substances,

the measurement unit includes:

a shaft portion that passes through the fitting hole and that extends into the tube inner flow path;

a shaft through hole that penetrates a portion of the shaft portion that protrudes into the flow path in the cylinder in an axial direction of the cylindrical body; and

a measuring unit that measures a flow rate of the fluid flowing through the shaft through-hole,

the fitting holes are provided in pairs so as to face each other in the radial direction of the cylindrical body,

the shaft portion is bridged over a portion of the cylindrical body where the pair of attachment holes are formed, and passes through both of the pair of attachment holes,

the shaft portion is formed in a structure in which the diameter thereof is reduced at an intermediate portion in the axial direction, and has a large diameter portion and a small diameter portion on one side and the other side in the axial direction with respect to the reduced diameter portion,

the pair of fitting holes includes: a large-diameter hole through which the large-diameter portion passes; and a small-diameter hole which is smaller than the large-diameter hole and through which the small-diameter portion passes,

the measurement unit includes:

a large diameter sealing member fitted to the large diameter portion to seal between the large diameter portion and the large diameter hole; and

and a small-diameter sealing member that is fitted to the small-diameter portion to seal between the small-diameter portion and the small-diameter hole.

2. The flow meter of claim 1,

the flow meter has:

a lower case having a pair of cutout portions that house an intermediate portion in the axial direction of the cylindrical body; and

and an upper housing fitted to an opening-side end of the lower housing.

3. The flow meter of claim 1,

a small-diameter enlarged portion having an enlarged diameter toward the inner flow path side of the cylinder is formed in a portion of the inner peripheral surface of the small-diameter hole adjacent to the inner flow path in the cylinder,

a large-diameter expanding portion that expands in diameter toward the outside of the tubular body is formed in a portion of the inner peripheral surface of the large-diameter hole that is adjacent to the outside of the tubular body.