JP2002188944A - Flow measuring device having restrictor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten measurement accuracy by suppressing adhesion of a scale on a restrictor with a simple constitution in a flow measuring device equipped with the restrictor. SOLUTION: This device is equipped with a device body 11 having a passage, and the restrictor 21 having a restriction hole 22, and has an upstream pressure hole 26 positioned in the liquid flow direction upstream relative to the restrictor and formed on the device body, and a downstream pressure hole 27 positioned in the liquid flow direction downstream relative to the upstream pressure hole. As for the restrictor 21, a working face 23 along the restrictor radial direction is formed on a part in the upstream relative to the restriction hole, and a mound part 25 having a circumferential side inclined face 25a inclined so as to be separated from the working face toward the upstream in proportion to the distance from the working face toward the restriction hole and an inside inclined face 25b inclined in succession to an opening of the restriction hole toward the downstream in proportion to the distance from a projection part of the circumferential side inclined face toward the restriction hole, is formed on the inner circumferential part in succession to the inner circumferential face of the restriction hole on the working face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow measuring device having a throttle body.

[0002]

2. Description of the Related Art A flow measuring device having a restrictor for measuring a flow rate of water flowing through a water supply system is provided in a water supply system provided in a general power plant. The flow measurement device having the throttle body includes a device body having a passage through which the liquid flows, and a throttle body provided in the passage of the device body and having a throttle hole parallel to the liquid flow direction in the throttle hole, An upstream pressure hole formed in the apparatus main body located on the upstream side in the liquid flow direction with respect to the throttle body, and a downstream formed in the apparatus main body located on the downstream side in the liquid flow direction with respect to the upstream extraction hole. It has side pressure holes. In other words, by passing to the downstream squeeze through aperture of the throttle hole from the upstream side flows of liquid, upstream pressure hole and the downstream pressure hole in the diaphragm member upstream of the (high pressure side) and the downstream side (low pressure side) Each pressure is taken out, the differential pressure is detected, and the differential pressure is converted into an electric signal or the like to measure the flow rate of the liquid. An orifice, a nozzle or a Venturi tube may be used as the throttle body.

[0003] By the way, a flow rate measuring device having a restrictor is subjected to an actual flow rate test at a stage before installation in a plant pipeline to determine a flow coefficient of the device, and to a differential pressure measured at the stage of installation in a plant pipeline. The flow rate of the liquid in the plant pipe is determined by multiplying the flow rate coefficient.
This test is performed as follows. That is, the target flow rate measuring device is incorporated in a pipe for verification, a liquid having a known flow rate is caused to flow through the pipe line, and the flow rate measuring device measures the flow rate of the liquid. The known flow rate (Q ₀ ) is divided by the flow rate (Q _{+ h} ) measured by the apparatus to obtain a flow coefficient α (outflow coefficient C). And, when installing the flow measurement device in the plant pipeline and performing flow measurement,
The differential pressure ΔP between the upstream side and the downstream side of the throttle body is constantly detected, and the flow coefficient α (outflow coefficient C) is calculated as the square root of the differential pressure ΔP.
To obtain the flow rate of the liquid flowing through the plant pipeline, that is, to measure the flow rate.

[0004]

Conventionally, the flow rate measuring device has the following problems. Depending on the components contained in the liquid flowing through the pipeline of the plant in which the flow rate measuring device is installed, the scale adheres to the throttle body in the flow rate measuring device, which has an adverse effect on the flow rate measurement. For example, iron ions contained in the liquid precipitate and iron oxide scale adheres to the surface of the drawn body.

An adverse effect of the scale on flow rate measurement will be described with reference to FIGS. 4 and 5 (a) and 5 (b), taking a flow rate measuring device using an orifice as a throttle body as an example. In FIG. 4, reference numeral 1 denotes an apparatus main body constituting a passage 2.
The liquid flows in the direction indicated by the arrow. Reference numeral 3 denotes an orifice-type diaphragm. The aperture body 3 is a disk, and has a circular aperture 4 at the center. The contact surface 5 and the downstream side surface 6, which are the upstream surfaces in the liquid flow direction, of the throttle body 3 are each perpendicular to the liquid flow direction. Reference numeral 7 denotes an upstream pressure hole formed in the apparatus main body 1 located on the upstream side in the liquid flow direction with respect to the throttle body 3, and 8 denotes a pressure hole located on the downstream side in the liquid flow direction with respect to the throttle body 3 in the apparatus main body 1. It is a downstream pressure hole formed.

When the liquid flows in the direction of the arrow shown in the figure, a part of the liquid directly passes through the throttle hole 4 of the throttle body 3, and the other part hits the hitting surface 5 and changes its direction. pass. The pressure difference between the liquid on the upstream side and the liquid on the downstream side in the liquid flow direction with respect to the throttle body 3 taken out by the upstream pressure hole 7 and the downstream pressure hole 8 is detected, and the flow rate of the liquid is obtained by using this pressure difference.

In this flow rate measuring device, a scale A adheres to the surface of the throttle body 3 as shown in FIGS. 4 and 5 (b) due to components such as iron contained in the liquid flowing through the passage 2 of the device main body 1. Specifically, the scale A adheres to the edge portion (around the inner peripheral surface of the contact surface 5 of the aperture body 3 and the upstream opening of the aperture 4). When the thickness of the scale A reaches about 0.1% of the diameter of the throttle hole and the scale A protrudes in a direction against the flow of the liquid from the upstream, the position where the liquid peels off is originally the scale. If there is no A, the liquid is at the edge as shown in FIG. 5A, whereas the liquid moves upstream from the edge in the liquid flow direction as shown in FIG. Become like Then, the turbulence in the low-speed area B due to the separation of the liquid in the throttle hole 4 increases. For this reason, the downstream pressure taken out by the downstream pressure hole 8 changes, and the pressure difference between the upstream pressure hole 7 and the pressure in the liquid flow direction of the throttle body 3 taken out by the downstream pressure hole 8 (difference). Pressure) changes, and the measurement accuracy of the flow rate value finally measured is reduced.

[0008] Therefore, in the conventional flow rate measuring device, the surface of the drawn body is subjected to a treatment such as plating or coating to make it difficult to attach a scale, thereby suppressing the adhesion of the scale. However, this countermeasure by the surface treatment is relatively effective for a flow nozzle type throttle or a Ventelli tube type throttle, but for an orifice type throttle, a low flow rate region (residence portion). There is a concern about the adhesion of the scale due to the presence of.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flow rate measuring apparatus provided with a throttle body having a simple structure and suppressing the scale from adhering to the throttle body and improving measurement accuracy.

[0010]

According to a first aspect of the present invention, there is provided a flow rate measuring apparatus having a throttle body, the apparatus body having a passage through which a liquid flows, and a passage provided in the apparatus body and being parallel to a liquid flow direction. A throttle body having a throttle hole, and an upstream pressure hole formed in the apparatus main body located on the upstream side in the liquid flow direction with respect to the throttle body, and a downstream in the liquid flow direction with respect to the upstream pressure hole. The throttle body has a contact surface formed in a radial direction of the throttle body surrounding the throttle hole in a portion on the upstream side in the liquid flow direction with respect to the throttle hole. An inner peripheral portion of the contact surface that is continuous with the upstream opening of the throttle hole has an outer peripheral side that is inclined away from the contact surface toward the liquid flow direction upstream toward the liquid flow direction as approaching the throttle hole from the contact surface. Inclined surface and outer peripheral side inclination The inner peripheral side which is located on the inner circumferential side of the throttle body with respect to the surface and is inclined toward the downstream side in the liquid flow direction and continues to the upstream opening of the throttle hole as approaching the throttle hole from the protrusion of the outer peripheral side inclined surface. A mound portion having an inclined surface is formed.

According to a second aspect of the present invention, there is provided a flow rate measuring apparatus having a throttle body, comprising: a device main body having a passage through which a liquid flows; and a throttle hole provided in the passage of the device main body and parallel to the liquid flow direction. An upstream pressure hole formed in the apparatus main body and located on the upstream side in the liquid flow direction with respect to the throttle body, and located on the downstream side in the liquid flow direction with respect to the upstream pressure hole. The throttle body has a cylindrical portion that forms a guide hole for guiding liquid from the liquid flow direction upstream side to the throttle hole with respect to the throttle hole. The guide hole forms an upstream arc surface inclined from the outer peripheral edge of the cylindrical portion to the inner peripheral portion of the cylindrical portion while the upstream portion in the liquid flow direction is directed to the outer peripheral side of the cylindrical portion, and the downstream portion in the liquid flow direction is the upstream side. Continuously from the inner peripheral end of the arc surface While the direction to the peripheral side is inclined to the cylinder inner peripheral portion, characterized in that forming the downstream arcuate surface contiguous to the upstream opening of the throttle hole.

According to a third aspect of the present invention, there is provided a flow rate measuring apparatus having a throttle body, which has a device main body having a passage through which a liquid flows, and a throttle body provided in the passage of the device main body and having a throttle hole parallel to the liquid flow direction. An upstream pressure hole formed in the apparatus main body and located on the upstream side in the liquid flow direction with respect to the throttle body, and a downstream side located on the downstream side in the liquid flow direction with respect to the upstream pressure hole. A pressure hole, and the throttle body has a hole formed therein, which is perpendicular to the axial direction of the throttle hole and inclined with respect to the circumferential direction of the throttle hole, and one end of the hole is formed as an inlet to the throttle hole. On the other hand, an opening is provided on a portion on the upstream side in the liquid flow direction, and the other end is provided on the inner peripheral surface of the throttle hole as an outlet.

According to a fourth aspect of the present invention, in the flow rate measuring apparatus having the throttle body according to the first or second aspect, the downstream pressure hole is formed in the throttle body, and a liquid inlet of the downstream pressure hole is formed in an inner periphery of the throttle hole. It is characterized by being formed on the surface.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. This embodiment is applied to a flow measuring device provided with an orifice-type restrictor, and FIG. 1 is a sectional view schematically showing the flow measuring device in this embodiment.

In FIG. 1, reference numeral 11 denotes an apparatus main body, and the apparatus main body 11 constitutes a passage 12 having a circular cross section open at both ends. This device body 11 is used for verification at the time of verification,
When the plant is installed, it is incorporated into the pipeline 101 for the plant so as to be located on the same central axis. The liquid flows from left to right in the drawing.

Reference numeral 21 denotes an orifice-type aperture member. The aperture member 21 is formed of a disk having a diameter larger than the diameter of the passage 12 of the apparatus body 11, and has two surfaces 2 on its center axis.
A circular throttle hole 22 penetrating between 3 and 24 is formed. The aperture body 21 has a central axis line corresponding to the passage 1.
2 so that the surfaces 23 and 24 on both sides thereof are aligned with the central axis O at right angles to the central axis O.
The peripheral edge portion is held and fixed to the apparatus main body 11.

Here, the throttle hole 22 is located on the center axis of the passage 12 and in parallel with the passage 12. A surface 23 located on the upstream side (left side in the drawing) of the throttle body 21 in the liquid flow direction (along the radial direction of the throttle body) serves as a contact surface at which the flowing liquid makes a right angle. ).

The diaphragm 21 has a contact hole 23 on its inner peripheral portion which is continuous with the inner peripheral surface of the diaphragm hole 22 on the contact surface 23.
An annular mound portion 25 is formed so as to surround the entirety in the circumferential direction. The mound portion 25 has an annular outer peripheral side inclined surface 25a which is inclined away from the contact surface 23 toward the upstream side in the liquid flow direction as approaching from the contact surface 23 to the throttle hole 22, and an outer peripheral side inclined surface 25a. The inner side which is located on the inner peripheral side of the throttle body 21 and is inclined toward the downstream side in the liquid flow direction as it approaches the throttle hole 22 from the projection of the outer peripheral inclined surface 25 a and continues to the upstream opening of the throttle hole 22. And an inclined surface 25b.

The mound portion 25 flows through the passage 12 of the apparatus main body 11 as will be described later, and
In addition to smoothly guiding the liquid striking toward the throttle hole 22 and quickly flowing the liquid, the separation of the liquid from the inner peripheral surface of the throttle hole 22 when the liquid passes through the throttle hole 22 is suppressed. In this embodiment, the outer peripheral side inclined surface 25a and the inner inclined surface 25b each form an arc drawn at a predetermined curvature with the center point inside the diaphragm 21 (an arc protruding outward from the diaphragm).

Incidentally, plating or coating is applied to the entire surface of the throttle body 21 in order to prevent the scale due to the components contained in the liquid from adhering.

An upstream pressure hole 26 is formed in the apparatus main body 11 at a position upstream of the throttle body 21 in the liquid flow direction. The upstream pressure hole 26 has one end facing the passage 12 as a liquid inlet. And the other end is the device body 1
1 is open on the outer peripheral surface. The throttle body 21 has a downstream pressure hole 27 located downstream of the upstream pressure hole 26 in the liquid flow direction. This downstream pressure hole 27 is formed along the radial direction of the throttle body 21, and one end is opened as a liquid inlet on the inner peripheral surface of the throttle hole 22 at a position close to the liquid flow direction downstream opening in the throttle hole 22. The end is open on the outer peripheral surface of the diaphragm 21. The downstream pressure hole 27
Is formed over the apparatus main body 11 and opens on the outer peripheral surface of the apparatus main body 11.

The other end opening of the upstream pressure hole 26 and the other end opening of the downstream pressure hole 27 are connected to a differential pressure transmitter 51 provided outside the apparatus main body 11. This differential pressure transmitter 5
Numeral 1 is for receiving the liquid from both the pressure holes 26 and 27, detecting the difference between the pressures of the respective liquids, and extracting it as an electric signal. The differential pressure transmitter 51 is connected to a flow meter 52. The flow rate measuring device 52 measures the flow rate of the liquid flowing in response to the signal from the differential pressure transmitter 51.

The diameter D of the passage 12 of the apparatus body 11
The diameter d and the length of the aperture 22 of the aperture body 21 are set based on the standard. For example, the diameter d of the throttle hole 22 / the passage 1
The aperture ratio indicated by the inner diameter D of 2 is about 0.7.

The operation of the thus configured flow rate measuring device will be described. This flow rate measuring device performs an actual flow rate test to determine a flow rate coefficient of the device, and then is installed in a pipe 101 of a plant. FIG. 1 shows a form in which the flow rate measuring device is installed at a location between the pipes 101 and 101.

The case where the flow measuring device installed in the pipe 101 of the plant measures the flow will be described. As shown by the arrow in FIG. 1, the pipeline 10 on the upstream side (left side) in the liquid flow direction.
1 flows from the opening in the apparatus main body 11 into the portion of the passage 12 on the upstream side (left side) in the liquid flow direction, and then passes through the throttle hole 22 of the throttle body 21 to the downstream side of the passage 12 in the liquid flow direction ( The liquid flows through the pipe 101 on the downstream side (right side) in the liquid flow direction from the opening through the portion (right side).

As the liquid passes through the throttle hole 22 of the throttle body 21 and is throttled, the liquid pressure on the upstream side in the liquid flow direction of the throttle body 21 in the passage 12 is high, and the liquid pressure on the downstream side (right side) in the liquid flow direction is high. The liquid pressure decreases. The liquid on the upstream side in the liquid flow direction with respect to the throttle body 21 in the passage 12 is taken into the upstream pressure hole 26 from the inlet thereof, and the liquid on the downstream side in the liquid flow direction with respect to the throttle body 21 flows into the downstream pressure hole 27. It is taken in from the entrance. The differential pressure transmitter 51 receives the liquid from both of the pressure holes 26, 26, detects the pressure difference between the respective liquids, extracts it as an electric signal, and outputs this signal to the flow rate measuring device 52. The flow meter 52 receives the signal from the differential pressure transmitter 51 and measures the flow rate of the liquid flowing through the pipe 101.

Here, the flow of the liquid in the throttle body 21 will be described. The central portion of the liquid flowing in the upstream portion of the passage 12 of the apparatus main body 11 in the liquid flow direction passes directly through the throttle hole 22 and flows to the upstream portion of the passage 12 in the liquid flow direction. The outer peripheral portion surrounding the throttle hole of the liquid, which occupies a large part of the cross-sectional area of the passage 12, abuts on the upstream side surface of the throttle body 21 in a direction perpendicular to the contact surface 23 surrounding the throttle hole 22. The liquid that has hit the contact surface 23 changes its direction so as to concentrate toward the throttle hole 22 of the throttle body 21 (because diffusion to the outer peripheral side is restricted by the passage 12 of the apparatus main body 11). The liquid flowing toward the throttle hole 22 of the throttle body 21 has a mound portion 25 formed in an annular shape around the entire circumferential direction of the throttle hole 22 on the inner surface of the contact surface 23 that is continuous with the opening of the throttle hole 22. It reaches the outer peripheral side inclined surface 25a and is guided along the outer peripheral side inclined surface 25a so as to move away from the contact surface 23 toward the upstream side in the liquid flow direction as it approaches the restriction hole of the restrictor 21 from the contact surface 23 and becomes stable. It becomes a flow. The liquid continuously reaches the inner peripheral side inclined surface 25b from the projecting portion of the outer peripheral side inclined surface 25a. As the liquid approaches the restricting hole 22 along the inner peripheral side inclined surface 25b, the liquid flows into the throttle hole 22 toward the downstream side in the liquid flow direction. It is smoothly guided toward the periphery and flows vigorously. As a result, the liquid is guided by the outer peripheral side inclined surface 25a and the inner peripheral side inclined surface 25b of the mound portion 25 of the throttle body 21, flows quickly and vigorously inside the throttle hole 22, passes through the downstream opening, and flows downstream of the passage 12. Runs out to the side part.

As described above, the liquid is supplied to the throttle hole 22 of the throttle body 21.
Flow fast without delamination. For this reason, even if the scale is attached by the component contained in the liquid at the corner where the contact surface 23 and the opening of the throttle hole 22 intersect, the scale is suppressed by being pushed by the flowing liquid and flowing away. Thus, the separation point of the liquid moves to the upstream side due to the adhesion of the scale, and the generation of the portion where the flow of the liquid is extremely slow due to the movement of the separation point of the liquid can be suppressed. Further, since the liquid flows through the throttle hole 22 of the throttle body 21 at a high speed, it is possible to suppress the occurrence of a portion where the flow of the liquid is extremely slow on the wall surface of the throttle hole 22. Further, the downstream pressure hole 27 is open at one end as a liquid inlet facing the throttle hole 22 at a position close to the downstream opening in the liquid flow direction in the throttle hole 22, so that the downstream pressure hole 27 is located at a location where the liquid flow is fast. Liquid pressure can be introduced.

Due to these facts, the liquid pressure on the downstream side taken out by the downstream pressure hole 27 does not change, and as a result, the upstream side in the liquid flow direction of the throttle body 21 taken out by the upstream pressure hole 26 and the downstream pressure hole 27. and can be the difference between the pressure at the downstream side (the differential pressure) is not able to change to obtain a high measurement accuracy can be accurately measuring the flow rate of liquid through the flow meter 52 through the differential pressure transmitter 51. Therefore, it is possible to accurately measure the flow rate of the liquid using the throttle body having a simple configuration, and to obtain high measurement accuracy.

The mound portion 2 formed on the aperture body 21
The height protruding from the contact surface 23 toward the upstream side in the liquid flow direction is, for example, about 10 to 20% with respect to the diameter d of the throttle hole in the throttle body 21. The outer peripheral side inclined surface 25a and the inner peripheral side inclined surface 25b of the mound portion 25 are preferably arcuate surfaces protruding toward the outside of the drawing body as in this embodiment in order to effectively perform the operation of the mound portion 25. . However, the present invention is not limited to this.
May be, for example, an arc-shaped surface which is concave toward the inside of the drawing body, or a straight line.

This embodiment is suitable for installation in a pipe where space in the liquid flow direction is restricted because the thickness of the flow measuring device can be reduced because the throttle body 21 has a disk shape. ing.

A second embodiment will be described with reference to FIG. This embodiment is applied to a flow measuring device provided with a throttle body of a type combining an orifice type and a flow nozzle type. FIG. 2 is a cross-sectional view schematically showing a flow rate measuring apparatus according to this embodiment, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, reference numeral 31 denotes a circular aperture member.
A circular aperture 32 is formed at the center of the shape of the aperture body 31. A portion of the throttle body 31 which is on the upstream side in the liquid flow direction with respect to the throttle hole 32 is a guide hole 3 having a circular cross section for guiding the liquid from the upstream side in the liquid flow direction to the throttle hole 32.
4 is formed as a cylindrical tubular portion 33. The guide hole 34 forms an upstream arc surface 35 that is inclined from the outer peripheral edge of the cylindrical portion 33 toward the inner peripheral side of the cylindrical portion 33 while the upstream portion in the liquid flow direction is directed to the outer peripheral side of the cylindrical portion 33. The downstream portion in the direction is continuously inclined from the inner peripheral end of the upstream circular arc surface 35 toward the inner peripheral side of the cylindrical portion 33 toward the inner peripheral side of the cylindrical portion 33 to be continuous with the upstream opening of the throttle hole 32. Downstream arc surface 3
6 to form a hole. The guide hole 34 guides the liquid smoothly toward the throttle hole 32, suppresses the separation of the liquid from the inner peripheral surface of the throttle hole 32 when passing through the throttle hole 32, and allows the liquid to flow vigorously. The upstream arc surface 35 of the guide hole 34 smoothly collects the liquid flowing through the passage 12 of the apparatus main body 11 at the center of the guide hole 34 to give momentum, and the downstream arc surface 36 subsequently squeezes the liquid smoothly. Hole 3
Give momentum while guiding you to 2.

The upstream pressure hole 26 is formed in the apparatus main body 11 at a position upstream of the throttle body 31 in the liquid flow direction, and the downstream pressure hole 27 is formed in a downstream portion of the throttle body 31 in the liquid flow direction. One end of the downstream pressure hole 27 faces the throttle hole 32 at a position close to the downstream opening in the liquid flow direction in the throttle hole 22 as a liquid inlet. The downstream pressure hole 27 extends in the radial direction of the throttle body 31 from this opening. The end is open on the outer peripheral surface of the diaphragm 31.

The flow of the liquid in the throttle body 31 will be described. The liquid flowing on the upstream side in the liquid flow direction in the passage 12 of the apparatus main body 11 is supplied to the guide hole 34 of the throttle body 31.
It is smoothly collected at the center of the guide hole 34 by the upstream arcuate surface 35 in the guide hole 34, and is supplied with momentum and flows. Subsequently, the liquid is further collected by the downstream circular arc surface 36, smoothly guided toward the upstream opening of the throttle hole 32, and flows vigorously. For this reason, the liquid flows quickly and vigorously through the inside of the throttle hole 32 with the separation being suppressed,
It flows out through the downstream port to the downstream portion of the passage 12.

For this reason, even if the scale contained in the liquid adheres to the inner peripheral surface of the throttle hole 32, the scale can be pressed and flown by the flowing liquid to suppress the adhesion of the scale. It is possible to suppress the movement of the liquid peeling point to the upstream side and the occurrence of the portion where the liquid flow is extremely slow due to the movement of the liquid peeling point. Further, since the liquid quickly flows through the throttle hole 32 of the throttle body 31, it is possible to prevent the downstream portion of the throttle hole 32 and the vicinity of the downstream side surface 24 of the throttle body 31 from generating an extremely slow flow portion of the liquid. Can be. Further, the downstream pressure hole 27 has one end opened at a position close to the downstream opening of the throttle hole 22 in the liquid flow direction, so that the pressure of the liquid on the downstream side can be taken in a place where the flow of the liquid is fast.
From these facts, the liquid pressure on the downstream side taken out by the downstream pressure hole 27 does not change, and the difference between the pressure on the upstream side and the pressure on the downstream side in the liquid flow direction with respect to the throttle body 31 does not change. And high measurement accuracy can be obtained. Therefore, it is possible to accurately measure the flow rate of the liquid using the throttle body having a simple configuration, and to obtain high measurement accuracy.

This embodiment is suitable for the case where the axial length of the throttle body 31 is large and thus there is room in the pipe line 101 in the axial direction.

[0038] With reference to FIG. 3 illustrating a third embodiment. This embodiment is applied to a flow measuring device provided with an orifice type throttle body. FIG. 3A is a cross-sectional view schematically showing a flow rate measuring apparatus according to this embodiment, and FIG. 3B is a cross-sectional view taken along the line CC of FIG. Are denoted by the same reference numerals.

In FIG. 3, reference numeral 41 denotes an orifice-type aperture member.
A circular throttle hole 42 penetrating between four spaces is formed. The surface 43 (along the radial direction of the throttle body) located on the upstream side (in the drawing, on the left side) in the liquid flow direction of the throttle body 41 is a contact surface at which the liquid flowing at right angles is contacted. ). A plurality of holes 45 are formed inside the aperture body 41 at equal intervals in the circumferential direction so as to surround the aperture hole 42. These holes 45 are perpendicular to the axial direction of the throttle hole 42 and inclined with respect to the circumferential direction of the throttle hole 42. One end of each of the holes 45 located on the outer peripheral side of the throttle body 41 is formed along the axial direction of the throttle hole 42 toward the upstream side in the liquid flow direction, and the tip (one end) serves as a liquid inlet and is a contact surface of the throttle body 41. 43
And the other end is opened at the inner peripheral surface of the throttle hole 42 as a liquid outlet. These holes 45 guide the flowing liquid and eject it obliquely into the throttle hole 42, thereby forming the throttle hole 4.
A force is applied to the liquid flowing inside 2 to form a swirling flow. The downstream opening of the throttle hole 42 in the liquid flow direction and the other surface 4
4 is formed as a relief portion 41a as a tapered portion whose diameter increases at a predetermined clearance angle toward the downstream side in the liquid flow direction.

In this embodiment, an upstream pressure hole 46 opened in the passage 12 is formed in a portion of the apparatus main body 11 located on the upstream side in the liquid flow direction with respect to the throttle body 41, and is located on the downstream side in the liquid flow direction. Passage 12
A downstream pressure hole 47 that opens at the opening is formed.

The flow of the liquid in the throttle body 41 will be described. The liquid flowing in the upstream portion of the passage 12 of the apparatus main body 11 in the liquid flow direction is supplied to the throttle hole 42 of the throttle body 41.
And flows to the downstream portion of the passage 12 in the liquid flow direction. Here, a part of the liquid flowing in the upstream portion of the passage 12 in the liquid flow direction is applied to a contact surface 43 of the throttle body 41.
Then, the gas flows into the holes 45 from one end openings of the holes 45, and flows through the inside of the holes 45, and is ejected from the other end openings formed on the inner peripheral surface of the stop hole 42 to the stop hole 42. In this case, the liquid ejected from each of the holes 45 is perpendicular to the axial direction of the orifice 42 and at several points at equal intervals throughout the circumferential direction of the orifice 42, depending on the form of the orifices 45. 42 is ejected in a direction inclined with respect to the circumferential direction. For this reason, from the upstream entrance of the throttle hole 42, the throttle hole 4
The liquid that has entered 2 flows and flows while vibrating around the central axis of the throttle hole 42 under the force of the liquid ejected from each hole 45. The liquid is thus formed into a swirling flow, quickly and vigorously flows through the inside of the throttle hole 42, and flows out from the downstream opening to the downstream side of the passage 12 of the apparatus main body 11 in the liquid flow direction.

For this reason, even if the scale adheres to the inner peripheral surface of the throttle hole 42 due to the components contained in the liquid, the scale is pushed by the flowing liquid and is prevented from adhering to the scale. It is possible to suppress the movement of the liquid peeling point to the upstream side and the occurrence of the portion where the liquid flow is extremely slow due to the movement of the liquid peeling point. Further, since the liquid quickly flows through the throttle hole 42 of the throttle body 41, it is possible to prevent the downstream portion of the throttle hole 42 and the vicinity of the downstream side surface 44 of the throttle body 41 from generating an extremely slow liquid flow portion. Can be. From these facts, the liquid pressure on the downstream side taken out by the downstream pressure hole 47 does not change and the difference between the pressure on the upstream side and the pressure on the downstream side in the liquid flow direction of the throttle body 31 does not change, and the flow rate of the liquid is accurately measured. And high measurement accuracy can be obtained. Therefore, it is possible to accurately measure the flow rate of the liquid using the throttle body having a simple configuration, and to obtain high measurement accuracy.

The present invention is not limited to the above-described embodiment, but can be implemented in various modifications.

[0044]

According to the flow rate measuring apparatus having the throttle body according to the first aspect of the present invention, the throttle body forms a contact surface along the radial direction of the throttle body at a portion upstream of the throttle hole in the liquid flow direction. In the inner peripheral portion of the contact surface, which is continuous with the upstream opening of the throttle hole, the outer peripheral side inclined surface separated from the contact surface toward the liquid flow direction upstream toward the liquid flow direction as approaching the restrictor hole from the contact surface, and As the mound portion having an inner inclined surface that is continuous to the opening of the throttle hole toward the liquid flow direction downstream as it approaches the throttle hole from the protrusion of the outer peripheral slope is formed, the liquid peels off the throttle hole of the throttle body. It flows fast without passing. Thus, it is possible to prevent the scale from adhering to the throttle body, and to suppress the occurrence of a portion where the flow of the liquid is extremely slow due to the separation point of the liquid moving upstream due to the adhesion to the scale. Further, since the liquid quickly flows through the throttle hole of the throttle body, it is possible to suppress the generation of a part where the flow of the liquid is extremely slow near the downstream side of the throttle hole and near the downstream side surface of the throttle body. Therefore, the pressure difference between the upstream side and the downstream side in the liquid flow direction of the throttle body does not change, and the flow rate of the liquid can be accurately measured with a simple configuration of the throttle body, so that high measurement accuracy can be obtained.

According to the flow rate measuring apparatus having the throttle body according to the second aspect of the present invention, the throttle body forms a guide hole for guiding the liquid to the throttle hole at a portion on the upstream side in the liquid flow direction with respect to the throttle hole. An upstream circular arc surface inclined from the outer peripheral edge of the cylindrical portion toward the inner peripheral side of the cylindrical portion while the guide hole faces the outer peripheral side of the cylindrical portion in the upstream portion in the liquid flow direction, and a cylindrical portion in the downstream portion in the liquid flow direction. since having a downstream arcuate surface contiguous to the upstream opening of the inclined with throttle hole toward while orientation to the inner peripheral side to the cylinder inner peripheral side, flows faster without causing the peeling of the liquid throttle hole.
Thus, it is possible to prevent the scale from adhering to the throttle body, and to suppress the occurrence of a portion where the flow of the liquid is extremely slow due to the adhesion of the scale. Further, since the liquid quickly flows through the throttle hole of the throttle body, it is possible to suppress the generation of a part where the flow of the liquid is extremely slow near the downstream side of the throttle hole and near the downstream side surface of the throttle body. Therefore, the pressure difference between the upstream side and the downstream side in the liquid flow direction of the throttle body does not change, and the flow rate of the liquid can be accurately measured with a simple configuration of the throttle body, so that high measurement accuracy can be obtained.

According to the flow rate measuring apparatus having the throttle body according to the third aspect of the present invention, the throttle body forms a hole inside the throttle body perpendicular to the axial direction of the throttle hole and inclined with respect to the circumferential direction of the throttle hole. Since one end of this hole was opened as an inlet to the upstream side of the throttle body and the other end was opened to the inner peripheral surface of the throttle hole as an outlet,
The liquid is swirled by the liquid ejected from the hole when passing through the throttle hole of the throttle body, and flows quickly through the throttle hole without causing separation. Accordingly, it is possible to suppress the scale from adhering to the throttle body, and to suppress the occurrence of a portion where the flow of the liquid is extremely slow due to the adhesion of the scale. In addition, since the liquid flows quickly through the throttle hole of the throttle body, it is possible to suppress the generation of a part where the flow of the liquid is extremely slow near the downstream side of the throttle hole and near the downstream side surface of the throttle body. Therefore, the pressure difference between the upstream side and the downstream side in the liquid flow direction of the throttle body does not change, and the flow rate of the liquid can be accurately measured with a simple configuration of the throttle body, so that high measurement accuracy can be obtained.

According to a fourth aspect of the present invention, in the flow rate measuring apparatus having the throttle body according to the first or second aspect, the downstream pressure hole is formed in the throttle body, and the liquid inlet is formed on the peripheral surface of the throttle hole. As a result, the pressure of the liquid on the downstream side can be taken in at places where the flow of liquid is fast, and the differential pressure on the upstream and downstream sides of the restrictor in the liquid flow direction is prevented from changing, and the flow rate of the liquid is accurately adjusted. Contributes to the measurement.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a flow rate measuring device according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically showing a flow measurement device according to a second embodiment.

FIG. 3 is a diagram schematically showing a flow measurement device according to a third embodiment.

FIG. 4 is a diagram schematically showing a flow measurement device according to a conventional embodiment.

FIG. 5 is a diagram schematically showing the operation of a flow measurement device according to a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Device main body 12 ... Passage 21 ... Restrictor 22 ... Restrictor hole 23 ... Contact surface 24 ... Surface 25 ... Mound part 25a ... Outer inclined surface 25b ... Inner inclined surface 26 ... Upstream pressure hole 27 ... Downstream pressure hole 31 ... Aperture body 32 ... Aperture hole 33 ... Cylinder 34 ... Guide hole 35 ... Upstream arc surface 36 ... Downstream arc surface 41 ... Aperture body 42 ... Aperture hole 45 ... Hole, 46 ... Upstream pressure hole 47 ... Downstream pressure hole .

Claims (4)

[Claims] An apparatus main body having a passage through which a liquid flows;
A restrictor provided in a passage of the apparatus main body and having a restrictor hole parallel to the liquid flow direction, wherein an upstream formed in the apparatus main body is positioned on the upstream side in the liquid flow direction with respect to the restrictor. A side pressure hole and a downstream pressure hole located on the downstream side in the liquid flow direction with respect to the upstream side pressure hole. A contact surface is formed around the throttle hole and extends in the radial direction of the throttle body, and an inner peripheral portion of the contact surface that is continuous with the upstream opening of the throttle hole has a liquid flow as the contact surface approaches the throttle hole. Outer peripheral side inclined surface that is inclined away from the contact surface toward the upstream side in the direction, and the liquid is located closer to the restrictor hole from the protruding portion of the outer peripheral side inclined surface that is located on the inner peripheral side of the diaphragm with respect to the outer peripheral side inclined surface. Tilt toward downstream in the flow direction A flow measuring device having a throttle body, wherein a mound portion having an inner peripheral side inclined surface which is inclined and continues to an upstream opening of the throttle hole is formed. 2. An apparatus body having a passage through which a liquid flows,
A restrictor provided in a passage of the apparatus main body and having a restrictor hole in the restrictor hole in parallel with the liquid flow direction, wherein the restrictor is located on the upstream side in the liquid flow direction with respect to the restrictor and formed in the apparatus main body. And a downstream pressure hole located on the downstream side in the liquid flow direction with respect to the upstream pressure hole. The throttle body has a liquid upstream side in the liquid flow direction with respect to the throttle hole. Is formed into a guide hole for guiding the liquid from the upstream side in the liquid flow direction to the throttle hole, and the guide hole extends from the outer peripheral edge of the cylindrical portion to the inner circumferential portion of the cylindrical portion with the upstream portion in the liquid flow direction facing the outer circumferential side of the cylindrical portion. While forming an upstream arc surface that slopes to the
The downstream arc in which the downstream portion in the liquid flow direction is continuously directed from the inner peripheral side end of the upstream arc surface to the inner peripheral side of the cylindrical portion and is inclined toward the inner peripheral portion of the cylindrical portion to be continuous with the upstream opening of the throttle hole. A flow measuring device having a restrictor, which forms a surface. 3. An apparatus body having a passage through which a liquid flows,
A restrictor provided in a passage of the apparatus main body and having a restrictor hole parallel to the liquid flow direction, wherein an upstream formed in the apparatus main body is positioned on the upstream side in the liquid flow direction with respect to the restrictor. A downstream pressure hole located downstream of the upstream pressure hole in the liquid flow direction with respect to the upstream pressure hole. The throttle body has a peripheral portion around the throttle hole at right angles to the axial direction of the throttle hole. inclined hole is formed with respect to the direction, one end of the hole opens into the portion to be the liquid flow upstream side with respect to the throttle hole as an inlet and the other end opened to the inner peripheral surface of the throttle hole as an outlet A flow rate measuring device having a throttle body characterized in that the flow rate is measured. 4. The throttle body according to claim 1, wherein the downstream pressure hole is formed in the throttle body, and a liquid inlet thereof is formed in an inner peripheral surface of the throttle hole. Flow measurement device.