WO2005121715A1

WO2005121715A1 - Restriction flowmeter

Info

Publication number: WO2005121715A1
Application number: PCT/JP2004/007931
Authority: WO
Inventors: Kenji Yao; Nobutaka Chimura; Hiroyuki Mutoh
Original assignee: Yamatake Corporation
Priority date: 2004-06-07
Filing date: 2004-06-07
Publication date: 2005-12-22
Also published as: CA2567284A1; CA2567284C

Abstract

A restriction flowmeter, comprising a measuring tube (31) having two members, that are, a primary measuring tube (31A) and a secondary measuring tube (31B). The primary measuring tube (31A) comprises a primary pressure outlet (4) and is flange-connected to a bent tube (21) after being angularly adjusted around its axis relative to the secondary measuring tube (31B). By this angular adjustment of the primary measuring tube (31A), the general average height of the primary pressure (PH) of measured fluid (7) near the primary pressure outlet (4) is allowed to generally match the height of the primary pressure outlet (4). Since the average height of the primary pressure (PH) of the measured fluid (7) near the primary pressure outlet (4) when the primary measurement tube (31A) is connected to the bent tube (21) is generally equal to the center height of the primary measurement tube (31A), the primary measuring tube (31A) is connected to the secondary measuring tube (31B) in the state of the primary pressure outlet (4) facing just sideways. The secondary measurement tube (31B) comprises a restrictor (3) and the secondary pressure outlet (5), and is flange-connected to a horizontal tube (20B) in the state of the secondary pressure outlet (5) facing upward.

Description

Specification

Throttle flow meter

Technical field

The present invention relates to a restrictor flow meter used for various plants such as natural gas, petrochemical, and chemical industries.

Background art

[0002] As one type of flow meter for measuring the flow rate of various fluids such as liquid, gas, and vapor flowing in a steady flow in a pipeline, a throttle flow meter has been conventionally used. This throttle flow meter is designed to guide the differential pressure generated by the throttle mechanism to a measuring unit, convert it into an electric signal, and calculate the flow rate from the signal. In other words, if a throttle mechanism for reducing the cross-sectional area of the pipe is provided in the middle of the pipe, a pressure difference occurs before and after the throttle mechanism when the fluid flows there. Since there is a correlation between the pressure difference and the flow rate, the flow rate of the measurement fluid flowing in the pipeline can be obtained by measuring the pressure difference. As the aperture mechanism, an orifice, flow nozzle, a bench lily tube or the like is used (for example, JP-A-7-139979, JP-A-06-213694, JP-A-9-159498, JP-A-10-160529). Gazette, JP-A-8-319730).

FIG. 5 is a cross-sectional view showing a conventional example of a throttle flow meter. The throttle flow meter 1 includes a measurement pipe 2 composed of a straight pipe. The measuring tube 2 has an integral throttle 3 inside, and a primary pressure outlet 4 and a secondary pressure outlet 5 on the upstream (primary side) and downstream (secondary side) of the pipe wall. It is formed. The aperture stop 3 is cylindrical, and is formed by a part of a substantially elliptic curve whose inner peripheral cross section has a minimum diameter at the center and expands toward both ends. Here, such an aperture 3 is also called an elliptical aperture. The primary pressure outlet 4 is provided so as to be located upstream of the elliptical throttle 3. The secondary-side pressure outlet 5 is provided at a minimum throttle diameter portion of the elliptical throttle 3 (or a portion displaced downstream from the minimum throttle diameter portion).

[0004] The primary-side pressure outlet 4 and the secondary-side pressure outlet 5 are provided to prevent the normal drain from accumulating in the primary and secondary pressure guiding tubes 8, 9 when the measurement fluid 7 is a gas. Open above the tube wall of the measuring tube 1, and a diaphragm type Connected to the differential pressure gauges 10 and connected.

[0005] The differential pressure gauge 10 includes a container 12 in which a liquid 11 such as silicone oil is sealed, and a center diaphragm 14 that divides the inside of the container 12 into two chambers, that is, a primary chamber 13a and a secondary chamber 13b. And high-pressure side and low-pressure side pressure receiving diaphragms 15, 16 and the like provided on both sides of the container 12, respectively. An outer chamber 17a is formed on the outer surface of the high-pressure side pressure receiving diaphragm 15, and a primary pressure P of the measuring fluid 7 flowing through the measuring pipe 2 is guided to the outer chamber 17a by the primary side impulse line 8. ing. Outside the low pressure side pressure receiving diaphragm 16

H

An outer chamber 17b is also formed on the side surface, and a secondary pressure P of the measurement fluid 7 in the measurement pipe 2 is guided to the outer chamber 17b by the secondary-side impulse line 9.

L

In the restrictor flow meter 1 having such a structure, when the measuring fluid 7 flows through the measuring pipe 2, the pressure of the measuring fluid 7 changes before and after the oval restrictor 3, and the pressure near the primary-side pressure outlet 4 is changed. The primary pressure P is guided to the outer chamber 17 a of the pressure receiving diaphragm 15 by the primary pressure pipe 8. on the other hand

H

, The secondary pressure P inside the elliptical aperture 3 is changed by the secondary pressure line 9 to the pressure receiving diaphragm 1.

L

6 is led to the outer chamber 17b. For this reason, the two pressure receiving diaphragms 15 and 16

H

二 (Ρ-P) between the pressure and the secondary pressure P.

L H L

Through the center diaphragm 14. Therefore, the center diaphragm 14 is also displaced in accordance with the differential pressure ΔΡ, and the amount of displacement is converted into an electric signal and subjected to arithmetic processing, whereby the flow rate of the measuring fluid 7 flowing in the measuring pipe 2 is measured.

Disclosure of the invention

Problems to be solved by the invention

[0007] As a connection structure of the measurement pipe 2 to the pipe 20 in such a throttle flow meter 1, when the measurement fluid 7 is a gas, generally no drain is accumulated in the pressure guiding pipes 8, 9 as shown in FIG. For this purpose, the measuring pipe 2 is connected to the pipe 20 with the primary pressure outlet 4 and the secondary pressure outlet 5 facing upward. In such a connection structure of the measurement pipe 2 to the pipe 20, when the measurement pipe 2 is used by flange connection immediately after the curved pipe 21 provided in the middle of the pipe 20, the measurement flowing through the curved pipe 21 is performed. Fluid 7 becomes a drift (swirl) in which the main flow (concentric flow centered on the center 〇 of the curved pipe 21) and the secondary flow (radial flow toward the center 流れ) are combined. . For this reason, the pressure of the measurement fluid 7 is Different pressure gradients occur in the same cross section orthogonal to the axis of the curved pipe 21. That is, the pressure (P) is high outside the bend of the curved pipe 21 and the pressure (P) is low inside the bend (P>

1 2 1

P).

2

[0008] Further, the primary pressure P in a cross section orthogonal to the axis near the primary pressure outlet 4 of the measurement fluid 7 flowing into the measurement pipe 2 through the curved pipe 21 is different, and a pressure gradient is generated. You

H

That is, as shown in Fig. 5, when the curved pipe 21 is an elbow that is bent by approximately 90 ° in a vertical plane, the primary pressure P near the primary pressure outlet 4 is located above the inner wall of the measuring pipe 2.

H

Pressure P and pressure P below the inner wall, and pressure P becomes higher than pressure P.

HI H2 HI H2

Thus, the pressure P becomes substantially average in the center of the inside of the measuring tube 2. As a result, measurement tube 2

H

The pressure P higher than the average primary pressure P in the section perpendicular to the axis

H HI

When the pressure is led from the side pressure outlet 4 to the differential pressure gauge 10 through the primary side impulse line 8, a measurement error occurs, and high-precision measurement cannot be performed.

[0009] In addition, inside the bend of the curved pipe 21, the pressure of the measurement fluid 7 drops in the flow direction up to the center AB of the curved pipe 21, so that the fluid 7 passes through the force center AB, which is a stable boundary layer. The vortex 19 occurs and becomes turbulent. On the other hand, outside the bend of the curved pipe 21, the boundary layer of the measurement fluid 7 is separated from the wall surface until reaching the center AB, and a vortex 19 ′ is generated to form a turbulent flow. Such a turbulent flow 19, 19 'gradually stabilizes and returns to a laminar flow if a straight pipe having a required length is provided horizontally downstream of the curved pipe 21. Further, the pressure of the measurement fluid 7 in the cross section orthogonal to the pipe axis is also gradually averaged, and the pressure gradient is eliminated. Therefore, if the primary pressure outlet 4 is provided at a position where the flow and pressure of the measurement fluid 7 are stable, a measurement error does not occur and high-precision measurement is possible. The length L of the straight line required to stabilize the flow and pressure of the measurement fluid 7 while applying force (when the measurement tube 2 is directly connected to the

1

Assuming that the diameter of the measuring tube 2 is D, the length of the flow side opening end force and the length of the measuring tube 2 to the primary pressure outlet 4) are 10 times longer than the diameter D. 2 itself has become a problem, and this has become a major obstacle to miniaturization and weight reduction.

[0010] As one of measures to prevent the influence of the pressure fluctuation caused by the curved pipe 21, various types of displacement of the primary pressure outlet 4 and the secondary pressure outlet 5 in the circumferential direction are required. It is conceivable that a measuring tube will be manufactured and selected according to the installation location. That is, primary A measuring pipe is manufactured by shifting the side pressure outlet 4 and the secondary side pressure outlet 5 by 90 ° in the circumferential direction, and this measuring tube is oriented with the primary side pressure outlet 4 sideways and the secondary side pressure outlet 5 Is connected to the curved pipe 21 upward, since the height of the primary pressure outlet 4 substantially matches the height of the average pressure P of the measuring fluid 7 flowing near the pressure outlet 4, the primary pressure outlet 4 Pressure outlet 4 to flat

H

An average primary pressure P can be taken out, and highly accurate measurement is possible. Also measure

H

Reduce the distance L from the primary open end of the pipe 2 to the primary pressure outlet 4 to 10D or less

1

That power s can.

In this case, the primary pressure outlet 4 and the secondary pressure outlet 5 of the measurement pipe 2 are not shifted in the circumferential direction and are shifted in the circumferential direction. Since the side pressure outlet 4 must be open on the left side and on the right side, there is a problem that the number of types of measuring tubes 2 increases, and the production, storage, and management of the measuring pipes become complicated. This is undesirable.

[0012] The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a primary-side pressure outlet even if pressure is fluctuated due to a drift in a measurement fluid due to a curved pipe. By adjusting the height to the optimum height, it is possible to extract the average primary pressure without increasing the length of the measuring tube itself, and to provide a throttle flowmeter that enables highly accurate measurement. Is to do.

Means for solving the problem

[0013] In order to achieve the above object of the present invention, a primary measuring pipe having a primary pressure outlet formed by dividing the measuring pipe with a measuring pipe through which a measuring fluid flows, and a secondary pressure are provided. A throttle flowmeter is provided which comprises an outlet and a secondary measurement pipe having a throttle, and in which the primary measurement pipe is connected to the secondary measurement pipe so as to be adjustable in angle around an axis.

The invention's effect

[0014] In the present invention, the primary-side measurement pipe is attached to the secondary-side measurement pipe at an angle adjusted around the axis in accordance with the installation conditions of the measurement pipe, so that the primary-side pressure outlet is made to average the measurement fluid. The height can be made to substantially match the height of the typical primary pressure. For example, if the curved pipe is bent in a vertical plane and its upstream open end is located below and its downstream open end is located above, the primary measurement pipe will have a primary pressure outlet with respect to the curved pipe. I'll look sideways (horizontally) With this connection, the average pressure near the primary pressure outlet can be extracted as the primary pressure. As a result, even if the drift occurs, the measurement error is small and the measurement accuracy can be improved.

In addition, when the primary measurement pipe is rotated by a predetermined angle around the axis, the primary pressure outlet can be directed in any of up, down, left and right directions, and can be used as a common part. Brief Description of Drawings

FIG. 1 is an external perspective view showing a first embodiment of a throttle flow meter according to the present invention.

FIG. 2 is a cross-sectional view of the throttle flow meter.

FIG. 3 is a cross-sectional view showing a throttle flow meter according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a third embodiment of the throttle flow meter according to the present invention.

FIG. 5 is a sectional view showing a conventional throttle flow meter.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a throttle flow meter according to the present invention will be described in detail based on an embodiment shown in the drawings.

Note that the same components as those described in the related art are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In FIGS. 1 and 2, the throttle flowmeter, which is generally designated by the reference numeral 30, comprises a measurement pipe 31 which is flanged in the middle of the pipe 20, a primary pressure P and a secondary pressure generated in the measurement pipe 31.

H

A differential pressure gauge 10 for detecting a differential pressure Δ Ρ (= Ρ — Ρ) with the force P is provided.

L H L

The pipe 20 is a vertical pipe 20 が through which the measurement fluid 7 flows upward from below, a curved pipe 21 connected to a downstream opening of the vertical pipe 20 と, and is located downstream of the curved pipe 21. A horizontal pipe 20 mm is provided, and a measuring pipe 31 is flange-connected between the curved pipe 21 and the horizontal pipe 20 mm.

[0018] The curved pipe 21 is formed of an elbow having a circular cross section and bent at approximately 90 ° in a vertical plane, and an upstream open end is directed downward and flange-connected to an upper end side opening of the vertical pipe 20Α. The downstream open end is oriented in the horizontal direction.

[0019] The measurement tube 31 is formed by being divided at a central portion in the longitudinal direction with a cross section orthogonal to the axis, so that the primary measurement tube 31A located on the upstream side and the secondary measurement tube 31 located on the downstream side. The tube 31B is composed of two members. The primary measurement tube 31A has the same diameter as the curved tube 21 A primary pressure outlet 4 for taking out the primary pressure P in the primary measurement tube 31A to the outside is formed at the longitudinal center of the wall surface. Also, primary side measurement

H

At both ends of the outer peripheral surface of the pipe 31A, flanges 32, 32 are integrally provided to protrude, respectively. A plurality of bolt through holes 33 are formed in each flange 32 at equal intervals in the circumferential direction of the flange 32. For example, eight bolt through holes 33 are formed at 45 ° intervals.

[0020] The secondary measurement pipe 31B is a straight pipe having the same outer diameter and diameter as the primary measurement pipe 31A, and is provided with an elliptical aperture 3 as an aperture at the center of the inside thereof. Similar to the conventional elliptical diaphragm 3 shown in FIG. 5, the elliptical diaphragm 3 is formed in a cylindrical shape having a circular cross section, and its inner peripheral cross-sectional shape has a minimum diameter at the center of the inside and expands toward both ends. It is formed by a part of. Also, the secondary pressure P in the elliptical throttle 3 is supplied to the secondary measurement pipe 31B.

L

A secondary pressure outlet 5 for taking out to the outside is formed. The secondary pressure outlet 5 is formed such that its inner end is open to the inner peripheral surface of the elliptical restrictor 3 and to the minimum restricting diameter portion, and its outer end is opened to the outer peripheral surface of the secondary measurement pipe 31B. I have. Further, flanges 35 are integrally provided at both ends of the outer peripheral surface of the secondary measurement tube 31B. These flanges 35 also have the same number of bolt insertion holes 36 as the flange 32 at equal intervals in the circumferential direction.

[0021] The primary side measurement pipe 31A and the secondary side measurement pipe 31B are connected by flange connection, that is, the flange 32 and the flange 35 facing each other are tightly connected via a packing 37, and the through holes 33, 36 are integrally connected by inserting a bolt (not shown) and fastening a nut. In this case, the primary-side measurement pipe 31A is connected to the secondary-side measurement pipe 31B in a state where the primary-side pressure outlet 4 is rotated 90 ° around the axis so that the primary-side pressure outlet 4 is directed to the side (horizontal direction). The curved pipe 21 and the primary measurement pipe 31A are also flange-connected via a packing 38. The secondary measurement pipe 31B is also flange-connected to the horizontal pipe 20B via the packing 39 with the secondary pressure outlet 5 facing upward.

The differential pressure gauge 10 includes a container 12 in which a liquid 11 is sealed, a center diaphragm 14 that divides the inside of the container 12 into a primary pressure chamber 13a and a secondary pressure chamber 13b, and a left and right side of the container 12. The primary and secondary pressure receiving diaphragms 15 and 16 respectively provided on the wall and the center It is composed of an arithmetic processing unit (not shown) that converts the displacement of one diaphragm 14 into an electric signal and performs arithmetic processing to calculate the flow rate of the measurement fluid 7 flowing in the measuring pipe 31. One end of the primary impulse line 8 for guiding the primary pressure P in the measuring tube 31 to the differential pressure gauge 10 has a primary end.

H

The other end is connected to the side pressure outlet 4, and the other end is connected to an outer chamber 17 a formed outside the primary pressure receiving diaphragm 15. The secondary pressure P in the same measuring pipe 31 is introduced to the differential pressure gauge 10.

L

The secondary-side pressure guiding tube 9 has one end connected to the secondary-side pressure outlet 5 and the other end connected to an outer chamber 17 b formed outside the secondary-side pressure receiving diaphragm 16.

In the restrictor flow meter 30 having such a structure, when the measurement fluid 7 flowing in the pipe 20, for example, a natural gas composed of principal component gas, flows into the measuring pipe 31, the pressure is increased before and after the elliptical restrictor 3. Changes, and the differential pressure Δ Ρ (Ρ -Ρ) is detected by the

H L

The flow rate of the measurement fluid 7 flowing in the inside 31 can be measured. That is, the primary pressure Ρ of the measurement fluid 7 in the measurement pipe 31 is guided to the pressure receiving diaphragm 15 through the pressure guiding pipe 8,

Η

The secondary pressure Ρ is guided to the pressure receiving diaphragm 16 via the pressure guiding pipe 9. For this reason, the pressure

L

The diaphragm 15 and the pressure receiving diaphragm 16 are displaced according to the differential pressure Δ Δ, and this displacement is transmitted to the center diaphragm 14 via the sealing liquid 11. The center diaphragm 14 is displaced in accordance with the differential pressure ΔΡ, and this displacement is converted into an electric signal, and the flow rate W of the measurement fluid 7 flowing in the measurement pipe 31 is measured by performing an arithmetic process. This flow rate W is obtained by the following equation (1).

W = CK- Δ Ρ ^1/2

Where C is the discharge coefficient, Κ is a constant (including the pipe diameter, fluid density, etc.), and Δ Ρ is the differential pressure.

Then, the flow rate W is recorded on a recorder and output to an external device.

Here, the measurement fluid 7 flowing in the curved pipe 21 becomes a swirling flow as described with reference to FIG. 5, and the pressure fluctuates. The pressure becomes では outside the bend, and becomes では inside the bend.

1 2

A pressure gradient occurs between the pressures (Ρ> Ρ). For this reason, in the primary measurement tube 31A,

1 2

Also in the same section (Ε—F) perpendicular to the axis and including the primary pressure outlet 4, the primary pressure Ρ differs depending on the height position, and the pressure of the measurement fluid 7 flowing along the upper inner wall surface Ρ

Η

The pressure 測定 of the measuring fluid 7 flowing along the inner wall surface The pressure in the vicinity becomes a substantially average pressure P. Therefore, make the primary pressure outlet 4 upward.

H

When the primary measurement pipe 31A is connected to the secondary measurement pipe 31B, the pressure P higher than the average pressure P of the measurement fluid 7 is guided to the differential pressure gauge 10 as the primary pressure.

H HI

A measurement error occurs by the difference Δ (= Ρ -Ρ) from the average pressure P, which lowers the measurement accuracy

H HI H

[0025] Therefore, as in the present embodiment, the primary-side measurement pipe 31A is connected to the secondary-side measurement pipe 31B so that the primary-side pressure outlet 4 is oriented substantially right beside the axis of the measurement pipe 31. And the pressure P

HI

And the pressure P can be led to the differential pressure gauge 10 as the primary pressure (P).

H2 H

Therefore, a measurement error due to pressure fluctuation does not occur, and the measurement accuracy can be improved.

[0026] Further, since the average primary pressure P can be taken out, the primary measurement pipe 31A

H

Increase the distance L from the open end of the primary side to the primary side pressure outlet 4 to 10D or more by increasing the length of the measuring pipe 31 that does not require a stable laminar flow of the measuring fluid 7 flowing in the primary measuring pipe 31A. Can be shortened. Since the measurement fluid 7 that has passed through the primary measurement pipe 31A is contracted by the elliptical restriction 3, the pressure fluctuation of the secondary pressure P is extremely small. According to

L

Although the direction of the secondary-side pressure outlet 5 is not specified, it is preferable that the outlet be directed upward to prevent the drain from accumulating in the pressure guiding tube 9.

The above-described embodiment shows an example in which the measuring pipe 31 is connected to the curved pipe 21 piped so as to be bent in the vertical plane. When connecting 31, the inside and outside of the bend of the curved pipe 21 in which pressure fluctuations occur are in the same horizontal plane, and the parts with average pressure are the upper and lower sides of the inner wall surface. Therefore, in this case, the primary side measurement pipe 31A may be connected to the secondary side pressure measurement pipe 31B such that the primary side pressure outlet 4 faces upward.

Further, in the above-described embodiment, the angle adjustment of the primary measurement pipe 31A with respect to the secondary measurement pipe 31B is performed every 45 °. However, the present invention is not limited to this. By doing so, the angle may be adjusted, for example, every 15 ° or 30 °.

The bent pipe 21 is not limited to an elbow having a bend angle of 90 °, but may be an appropriate bend angle other than 90 °, for example, an enolbow having a bend angle of 45 °.

FIG. 3 is a sectional view showing a second embodiment of the present invention. This embodiment is applied to a throttle flowmeter 42 using a bench lily pipe 41 as a throttle of a measurement pipe 40. The measuring pipe 40 is composed of a primary measuring pipe 40A having a primary pressure outlet 43 formed by being divided into two parts, and a secondary measuring pipe 40B composed of a bench lily pipe 41. The measuring tube is flanged. As in the first embodiment, the primary measurement pipe 40A is connected to the primary side of the measurement fluid 7 flowing through the primary measurement pipe 40A in accordance with the installation state of the curved pipe 21 (horizontal installation, vertical installation). Measure the secondary side so that the height of the substantially average pressure P near the pressure outlet 43 and the height of the primary pressure outlet 43 match.

H

The angle is adjusted around the axis with respect to the constant tube 40B and the flange is connected to the constant tube 40B. The primary pressure outlet 43 is connected to the differential pressure gauge 10 via the primary pressure line 8. A secondary-side pressure outlet 44 is formed in the minimum diameter portion of the bench lily tube 41. The secondary pressure outlet 44 is connected to a differential pressure gauge 10 via a secondary pressure line 9.

[0031] In the throttle flow meter 42 using such a bench lily pipe 41 as a throttle, the primary measurement pipe 40A is connected to the secondary measurement pipe 40B by adjusting the angle, and the average primary pressure P It is apparent that the same effect as in the first embodiment can be obtained by extracting

H

Will.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

In this embodiment, the measuring tube 50 is composed of two members, a primary measuring tube 50A and a secondary measuring tube 50B, which are formed separately, and the primary measuring tube 50A is axially aligned with the secondary measuring tube 50B. The angle is adjusted around the circumference and flange connection is performed. The primary-side measuring tube 50A has a primary-side pressure outlet 4 and is flange-connected to a curved tube (not shown). The primary side pressure outlet 4 is connected to a differential pressure gauge 10 via a primary side impulse line 8. A throttle member 52 is provided in the center of the inside of the secondary measurement pipe 50B.

The throttle member 52 of the secondary measurement tube 50B has a front end surface formed in a hemispherical shell shape in order to reduce fluid resistance, and a rear end portion is supported by a support beam 54. The axis of the throttle member 52 is substantially coincident with the axis of the secondary measurement tube 50B. An annular throttle gap 55 is formed between the outer peripheral surface of the throttle member 52 and the inner wall surface of the secondary measurement tube 50B. The difference P, P is caused.

H L

A first passage 56 and a second passage 57 orthogonal to each other are formed inside the throttle member 52. ing. The first passage 56 is formed in the radial direction of the throttle member 52, and has one end opening at the outermost surface on the outer peripheral surface of the throttle member 52 to form a secondary-side pressure outlet 56 a, and the inner end is throttled. It is located in the center of the inside of the member 52 and is connected to the second passage 57. The second passage 57 is formed axially at the center of the inside of the throttle member 52, the front end communicates with the first passage 56, and the rear end passes through the passage 58 formed inside the support beam 54, and the secondary passage is formed. It is connected to a differential pressure gauge 10 via a pressure tube 9.

[0035] Also in the throttle flow meter provided with such a throttle member 52, the primary measurement pipe 50A is connected to the secondary measurement pipe 50B by adjusting the angle, and the average primary pressure P is taken out.

H

Thus, it is clear that the same effect as in the first embodiment can be obtained.

Industrial applicability

The throttle flow meter according to the present invention is useful for measuring the flow rate of a measurement fluid such as natural gas.

Claims

The scope of the claims

[1] A primary measuring pipe having a primary pressure outlet formed by dividing the measuring pipe, and a secondary measuring pipe having a secondary pressure outlet and a restrictor are provided. Wherein the primary measurement pipe is connected to the secondary measurement pipe so as to be adjustable in angle around an axis.

[2] The primary measurement pipe is connected to the downstream side of the curved pipe, and the primary pressure outlet is an average of the measurement fluid flowing near the pressure outlet with respect to the secondary measurement pipe. 2. The throttle flow meter according to claim 1, wherein the throttle flow meter is connected by being angle-adjusted around an axis so as to have a height substantially equal to the height of the primary side pressure.

[3] The throttle according to claim 1, wherein the throttle provided in the secondary measurement tube is any one of a bench lily tube, an elliptical throttle, and a bullet-shaped throttle member. Throttle flow meter described in 2 above.