CA1179869A - Vortex flow meter - Google Patents
Vortex flow meterInfo
- Publication number
- CA1179869A CA1179869A CA000405773A CA405773A CA1179869A CA 1179869 A CA1179869 A CA 1179869A CA 000405773 A CA000405773 A CA 000405773A CA 405773 A CA405773 A CA 405773A CA 1179869 A CA1179869 A CA 1179869A
- Authority
- CA
- Canada
- Prior art keywords
- bluff body
- plates
- pipe
- fluid
- flow meter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/01—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by using swirlflowmeter
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
- G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
- G01F1/3209—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters using Karman vortices
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Fluid Mechanics (AREA)
- Measuring Volume Flow (AREA)
Abstract
R. H. Barnard 1 VORTEX FLOW METER
ABSTRACT OF THE DISCLOSURE
The performance of a vortex fluid flow meter is en-hanced by the provision of a pair of parallel guide plates between which the vortex generating body is mounted. The plates confine the fluid in the region of the body to a substantially two dimensional flow thus generating a highly regular vortex street. In an alternative configura-tion the bluff body is enclosed within a square or rec-tangular section tube and in this form may be used as a probe or insertion meter.
ABSTRACT OF THE DISCLOSURE
The performance of a vortex fluid flow meter is en-hanced by the provision of a pair of parallel guide plates between which the vortex generating body is mounted. The plates confine the fluid in the region of the body to a substantially two dimensional flow thus generating a highly regular vortex street. In an alternative configura-tion the bluff body is enclosed within a square or rec-tangular section tube and in this form may be used as a probe or insertion meter.
Description
1~7986~
R. H. Barnard 1 VORTEX FLOW METER
BACKGROUND OF THE INVENTI02~
This invention relates to fluid flow meters, and in ~articular to flow meters of the type in which the fluid flow rate is determined from measurements of the freguency at which vortices are shed from an obstruction in the fluid stream. The term fluid as employed herein is understood to include both liquids and gases.
.
PRIOR ART STATEMENT
W~en a conventional bluff body is placed in a uniform stream of fluid,two separated shear layers are formed one on each side of the body, the vorticity of the two layers being opposite. A mutual interaction occurs between these two l~yers and, in the absence of disturbing influences, a stable pattern of alternating (i.e. of opposite rotati~nal sensel vortices is formed downstream of the body. This phenomenon is well known in the art and is commonly called a vortex street. In a truly uniform two dimensional flow around certain bluff shapes, this vortex shedding shows a periodicity that is, as far as can be measurea, purely monotonic to the frequency and is linearly related to the stream velocity.
Various flow meters employing this principle have been described in the prior art. Typically, they comprise a bluff ~ody aisposed in a fluid stream and means for detecting the vortices produced by the interaction of the fluid with the body. Suitable conventional electronic circuitry then converts this frequency to a signal pro-portional to a velocity. Unfortunately, the flow of fluid in a pipe is often far from two-dimensional or uni~orm.
Thus, for example, a number of disturbing influences are present. Such flow conditions introduce an amplitude modulation of the vortex intensity thus leading to errors fl~
86~
R. H. Barnard 1 VORTEX FLOW METER
BACKGROUND OF THE INVENTI02~
This invention relates to fluid flow meters, and in ~articular to flow meters of the type in which the fluid flow rate is determined from measurements of the freguency at which vortices are shed from an obstruction in the fluid stream. The term fluid as employed herein is understood to include both liquids and gases.
.
PRIOR ART STATEMENT
W~en a conventional bluff body is placed in a uniform stream of fluid,two separated shear layers are formed one on each side of the body, the vorticity of the two layers being opposite. A mutual interaction occurs between these two l~yers and, in the absence of disturbing influences, a stable pattern of alternating (i.e. of opposite rotati~nal sensel vortices is formed downstream of the body. This phenomenon is well known in the art and is commonly called a vortex street. In a truly uniform two dimensional flow around certain bluff shapes, this vortex shedding shows a periodicity that is, as far as can be measurea, purely monotonic to the frequency and is linearly related to the stream velocity.
Various flow meters employing this principle have been described in the prior art. Typically, they comprise a bluff ~ody aisposed in a fluid stream and means for detecting the vortices produced by the interaction of the fluid with the body. Suitable conventional electronic circuitry then converts this frequency to a signal pro-portional to a velocity. Unfortunately, the flow of fluid in a pipe is often far from two-dimensional or uni~orm.
Thus, for example, a number of disturbing influences are present. Such flow conditions introduce an amplitude modulation of the vortex intensity thus leading to errors fl~
86~
-2- R. H. Barnard 1 in the interpretation of the output signal. It is well known that tha intensity of this modulation is determined partly by the relative dimension of the bluff body and the pipe in which it is mounted. It has, been found empirically that the optimum ratio of body diame!ter to pipe diameter is about 1 : 3 and many commercial meters employ a ratio of this order. However, employing a bluff body of such a relatively large size introduces a relatively large blockage causing high energy losses through the meter.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a vortex flow meter comprising: a pipe; a bluff body fixed in said pipe to shed vortices at a rate proportional to the flow rate of a fluid in said pipe; guide plate means to form a region of substantially two-dimensional fluid flow disposed parallel to the stream lines of the fluid and adjacent the body, wherein said guide plate means includes two guide plates and said bluff body extends beyond said guide plates.
According to another aspect of the invention there is pro~ided a vortex flow meter comprising: a pipe; a bluff body fixed in said pipe to shed vortices at a rate proportional to the flow rate of a fluid in said pipe; guide plate means to form a region of substantially two-dimensional fluid flow disposed parallel to the stream lines of the fluid and adjacent the body, wherein said guide plate means includes two guide plates that define a rectangular box whose axis of symmetry is parallel to the fluid flow and which surrounds said bluff body.
According to still another aspect of the invention there is provided vortex shedding apparatus comprising: a pipe having a cylindrical internal surface with an axis of symmetry; a wedge-shaped bluff body; first and second parallel plates fixed relative to said pipe inside thereof equidistant from, although on opposite sides of, said axis, 1~798~9 -2a- R. H. Barnard 1 said bluff body having a uniform transverse cross section in the shape of an isosceles triangle, the base of which lies in a plane normal to flow, said bluff body being symmetrical about said axis and having first and second side surfaces abutting facing surfaces of said first and second plates, respectively.
BRIEF DESCR I PT I ON OF THE DRAWINGS
In the accompanying drawings which illustrate exemplary embodiments of the present invention:
Fig. 1 is a perspective view of a bluff body assembly constructed in accordance with the present invention;
Fig. 2 is a front end elevational view of the assembly shown in Fig. l;
Fig. 3 is a vertical longitudinal sectional view of the vortex generator of Fig. l;
Figs. 4 and 5 are respectively perspective and front end elevational views of an alternative vortex generator arrangement constructed in accordance with the present invention; and Figs. 6, 7 and 8 are perspective, front end elevational and vertical longitudinal sectional views, respectively, of a third embodiment of the present invention.
-2a-li~98fi9 .
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a vortex flow meter comprising: a pipe; a bluff body fixed in said pipe to shed vortices at a rate proportional to the flow rate of a fluid in said pipe; guide plate means to form a region of substantially two-dimensional fluid flow disposed parallel to the stream lines of the fluid and adjacent the body, wherein said guide plate means includes two guide plates and said bluff body extends beyond said guide plates.
According to another aspect of the invention there is pro~ided a vortex flow meter comprising: a pipe; a bluff body fixed in said pipe to shed vortices at a rate proportional to the flow rate of a fluid in said pipe; guide plate means to form a region of substantially two-dimensional fluid flow disposed parallel to the stream lines of the fluid and adjacent the body, wherein said guide plate means includes two guide plates that define a rectangular box whose axis of symmetry is parallel to the fluid flow and which surrounds said bluff body.
According to still another aspect of the invention there is provided vortex shedding apparatus comprising: a pipe having a cylindrical internal surface with an axis of symmetry; a wedge-shaped bluff body; first and second parallel plates fixed relative to said pipe inside thereof equidistant from, although on opposite sides of, said axis, 1~798~9 -2a- R. H. Barnard 1 said bluff body having a uniform transverse cross section in the shape of an isosceles triangle, the base of which lies in a plane normal to flow, said bluff body being symmetrical about said axis and having first and second side surfaces abutting facing surfaces of said first and second plates, respectively.
BRIEF DESCR I PT I ON OF THE DRAWINGS
In the accompanying drawings which illustrate exemplary embodiments of the present invention:
Fig. 1 is a perspective view of a bluff body assembly constructed in accordance with the present invention;
Fig. 2 is a front end elevational view of the assembly shown in Fig. l;
Fig. 3 is a vertical longitudinal sectional view of the vortex generator of Fig. l;
Figs. 4 and 5 are respectively perspective and front end elevational views of an alternative vortex generator arrangement constructed in accordance with the present invention; and Figs. 6, 7 and 8 are perspective, front end elevational and vertical longitudinal sectional views, respectively, of a third embodiment of the present invention.
-2a-li~98fi9 .
-3- , R. H. sarnard 1 DESCRIPTION OF THE PREFERRED EMBODIME~JT
Referring to the drawings, a flow meter vortex generator is mounted in each of the pipe sections 11, 11' and 11" and includes bluff bodies 12, 12' and 12" disposed between pairs of parallel guide plates 13, 13' and 13".
The bluff bodies 12, 12', 12" may be entirely constrained between the two plates as shown in Figs. 1 and 2, or may alternatively extend across the full diameter of the pipes 11, 11' and 11" as shown-in Figs. 4 and 5. The plates 13, 13' and 13" (Figs. 6-8) are arranged parallel to the fluid streamlines, and define channels within the pipes 11, 11', 11" and within which channel the fluid is confined to a substantially two dimensional flow. The depth of the plates 13, 13', 13" may be such that they extend across the pipè as shown in Figs. 1, 2, 4 and 5, but this is not necessary as long as this depth is large relative to the corresponding bluff body face depth.
In the case of small bluff body to pipe diameter ratios, additional plates 14 as shown in Figs. 6, 7 and 8 may be added at right angles to the previously described plates 13, 13' or 13", ~hus enclosing the bluff body within a tube of square or rectangular cross section which may be loacte~ in any required part cf the fluid,stream Ly an~
convenient means. In this configuration, the bluff body 12" and its plates 13" and 14 may be used in the form of a probe or insertion meter which may be inserted into any stream of fluid. The use of a square or rectangular tube as described above, and illustrated in Figs. 6, 7 and 8, gives less signal modulation for a given size of bluff body than would be obtained by the use of a circular enclosing tube which is current practice, this reduction in modulation being the consequence of the more nearly two dimensional flow conditions produced within the square or rectangular section tube.
Vortices shed from the bluff body are detected by a conventional detector device (not shown) integral with or l~g~
Referring to the drawings, a flow meter vortex generator is mounted in each of the pipe sections 11, 11' and 11" and includes bluff bodies 12, 12' and 12" disposed between pairs of parallel guide plates 13, 13' and 13".
The bluff bodies 12, 12', 12" may be entirely constrained between the two plates as shown in Figs. 1 and 2, or may alternatively extend across the full diameter of the pipes 11, 11' and 11" as shown-in Figs. 4 and 5. The plates 13, 13' and 13" (Figs. 6-8) are arranged parallel to the fluid streamlines, and define channels within the pipes 11, 11', 11" and within which channel the fluid is confined to a substantially two dimensional flow. The depth of the plates 13, 13', 13" may be such that they extend across the pipè as shown in Figs. 1, 2, 4 and 5, but this is not necessary as long as this depth is large relative to the corresponding bluff body face depth.
In the case of small bluff body to pipe diameter ratios, additional plates 14 as shown in Figs. 6, 7 and 8 may be added at right angles to the previously described plates 13, 13' or 13", ~hus enclosing the bluff body within a tube of square or rectangular cross section which may be loacte~ in any required part cf the fluid,stream Ly an~
convenient means. In this configuration, the bluff body 12" and its plates 13" and 14 may be used in the form of a probe or insertion meter which may be inserted into any stream of fluid. The use of a square or rectangular tube as described above, and illustrated in Figs. 6, 7 and 8, gives less signal modulation for a given size of bluff body than would be obtained by the use of a circular enclosing tube which is current practice, this reduction in modulation being the consequence of the more nearly two dimensional flow conditions produced within the square or rectangular section tube.
Vortices shed from the bluff body are detected by a conventional detector device (not shown) integral with or l~g~
-4- R. H. Barnard 1 arranged downstream of bodies 12, 12', 12" and coupled to a suitable output device, the device being calibrated to provide an output indicative of the fluid flow rate or guantity passed in a given time interval.
The constructions and locations of conventional vortex detectors are well known in the art and need not therefore be described herein. Typically a detector may comprise one or more pressure responsive transducers.
The effect of the plates 13, 13', 13" on the fluid ~low is a function of the plate dimensions relative to those of pipes 11, 11', 11" and to the distance between the plates. In general, however, the use of a pair of guide plates 13, 13', 13" substantiaily reduces the problem of vortex amplitude modulation and thus permits the use of relatively small bluff bodies 12, 12', 12". This in turn provides a meter with a relatively low energy loss factor.
The dimensions of the components of the vortex meter _ will depend upon the particular application envisaged, and the degree of signal modulation which can be tolerated by the particular signal processing methods used.
The following examples give typical dimensions of two configurations. Typical performance characteristics together with corresponding data which might be obtained from a conventional high blockage type of meter with no plates are given. The working fluid in the following may ~e air.
Data for a typical meter with plates 13' and bluff body 12' spanning the pipe 11', as shown in Figs. 4 and 5O
Test body 12' configuration: Wedge shape as illustrated in Figs. 4 and 5.
Test section diameter of pipe 11': 4 inches.
Ratio of spanwise separation of plates 13' to diameter of pipe 11': 0.4:1 ~atio of bluff body 12' upstream face depth to diameter of pipe 11': 0.15:1 1~79B6~
The constructions and locations of conventional vortex detectors are well known in the art and need not therefore be described herein. Typically a detector may comprise one or more pressure responsive transducers.
The effect of the plates 13, 13', 13" on the fluid ~low is a function of the plate dimensions relative to those of pipes 11, 11', 11" and to the distance between the plates. In general, however, the use of a pair of guide plates 13, 13', 13" substantiaily reduces the problem of vortex amplitude modulation and thus permits the use of relatively small bluff bodies 12, 12', 12". This in turn provides a meter with a relatively low energy loss factor.
The dimensions of the components of the vortex meter _ will depend upon the particular application envisaged, and the degree of signal modulation which can be tolerated by the particular signal processing methods used.
The following examples give typical dimensions of two configurations. Typical performance characteristics together with corresponding data which might be obtained from a conventional high blockage type of meter with no plates are given. The working fluid in the following may ~e air.
Data for a typical meter with plates 13' and bluff body 12' spanning the pipe 11', as shown in Figs. 4 and 5O
Test body 12' configuration: Wedge shape as illustrated in Figs. 4 and 5.
Test section diameter of pipe 11': 4 inches.
Ratio of spanwise separation of plates 13' to diameter of pipe 11': 0.4:1 ~atio of bluff body 12' upstream face depth to diameter of pipe 11': 0.15:1 1~79B6~
-5- R. H. Barnard 1 Ratio of overall streamwise length of plates 13' to diameter of pipe 11': 0.85:1 Ratio of length of plates 13' upstream of bluff body 12' upstream face to diameter of pipe 11': 0.15:1 Ratio of non-recoverable total pressure loss to upstream dynamic pressure: 0.76 Vortex signal sensing method: Differential pressure across leeward faces of body 12'.
Modulation ratio, defined as the ratio of the standard deviation of the pressure signal peaks to the mean of the pressure signal peak values: 0.12:1 - Data for a typical meter with plates 13, and the bluff body 12 entirely constrained between the plates 13 as shown in Figs. 1 and 2:
Test of body 12 configuration: Wedge shape as illustrated in Fi~s. 1 and 2.
Diameter of pipe 11: 4 inches.
Ratio of spanwise separation of plates 13 to diameter of pipe 11: 0.2:1 Ratio o upstream face of bluff body 12' depth to diameter of pipe 11: a.l5:1 Ratio of overall streamwise length of plates 13 to diameter of pipe ll: 2.3:1 Ratio of length of plates 13 upstream of bluff hody 12 at windward face to diameter of pipe 11: 0.3:1 Ratio of non-recoverable total pressure loss to upstream dynamic pressure: 0.17:1 Vorte~ signal sensing method: Same as in CASE 1.
Modulation ratio: 0.15:1 Reference data for a typical conventional high blockage meter ~ith no end plates.
1~98~9
Modulation ratio, defined as the ratio of the standard deviation of the pressure signal peaks to the mean of the pressure signal peak values: 0.12:1 - Data for a typical meter with plates 13, and the bluff body 12 entirely constrained between the plates 13 as shown in Figs. 1 and 2:
Test of body 12 configuration: Wedge shape as illustrated in Fi~s. 1 and 2.
Diameter of pipe 11: 4 inches.
Ratio of spanwise separation of plates 13 to diameter of pipe 11: 0.2:1 Ratio o upstream face of bluff body 12' depth to diameter of pipe 11: a.l5:1 Ratio of overall streamwise length of plates 13 to diameter of pipe ll: 2.3:1 Ratio of length of plates 13 upstream of bluff hody 12 at windward face to diameter of pipe 11: 0.3:1 Ratio of non-recoverable total pressure loss to upstream dynamic pressure: 0.17:1 Vorte~ signal sensing method: Same as in CASE 1.
Modulation ratio: 0.15:1 Reference data for a typical conventional high blockage meter ~ith no end plates.
1~98~9
-6- R. H. Barnard 1 Configuration of bluff body: Wedge shape spanning the pipe.
Pipe diameter: 4 inches.
Ratio of bluff body upstream face depth to pipe diameter:
9.3:1 Ratio of non-recoverable total pxessure loss to upstream dynamic pressure: 2.45:1 Vortex signal sensing method: As in CASE 1.
Modulation ratio as defined in CASE 1: 0.17:1 The data and dimensions given above do not necessarily represent optima, and are given purely for illustrative purposes.
ADS:dg
Pipe diameter: 4 inches.
Ratio of bluff body upstream face depth to pipe diameter:
9.3:1 Ratio of non-recoverable total pxessure loss to upstream dynamic pressure: 2.45:1 Vortex signal sensing method: As in CASE 1.
Modulation ratio as defined in CASE 1: 0.17:1 The data and dimensions given above do not necessarily represent optima, and are given purely for illustrative purposes.
ADS:dg
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A vortex flow meter comprising: a pipe; a bluff body fixed in said pipe to shed vortices at a rate proportional to the flow rate of a fluid in said pipe; guide plate means to form a region of substantially two-dimensional fluid flow disposed parallel to the stream lines of the fluid and adjacent the body, wherein said guide plate means includes two guide plates and said bluff body extends beyond said guide plates.
2. A flow meter as claimed in claim 1, wherein said bluff body and guide plates are mounted in a probe for insertion into a fluid stream.
3. A flow meter as claimed in claim 1, wherein said bluff body is of the reversed wedge type, and wherein the ratio of the upstream face area of the bluff body to the pipe diameter is less than 0.3 to to 1.
4. A flow meter as claimed in claim 1, wherein the modulation ratio as hereinbefore defined is less than 0.17 to 1.
5. A vortex flow meter comprising: a pipe; a bluff body fixed in said pipe to shed vortices at a rate proportional to the flow rate of a fluid in said pipe; guide plate means to form a region of substantially two-dimensional fluid flow disposed parallel to the stream lines of the fluid and adjacent the body, wherein said guide plate means includes two guide plates that define a rectangular box whose axis of symmetry is parallel to the fluid flow and which surrounds said bluff body.
6. Vortex shedding apparatus comprising: a pipe having a cylindrical internal surface with an axis of symmetry; a wedge-shaped bluff body; first and second parallel plates fixed relative to said pipe inside thereof - 8 - R. H. Barnard 1 equidistant from, although on opposite sides of, said axis, said bluff body having a uniform transverse cross section in the shape of an isosceles triangle, the base of which lies in a plane normal to flow, said bluff body being symmetrical about said axis and having first and second side surfaces abutting facing surfaces of said first and second plates, respectively.
7. The invention as set forth in claim 6, wherein first and second auxiliary wedges are provided and fixed between said first and second plates and respective walls of said pipe adjacent thereto, all the surfaces of said first and second auxiliary wedges lying approximately in the same planes as those of the respective surfaces of said bluff body, said bluff body being positioned midway between the upper and lower edges of said first and second plates.
8. The invention as set forth in claim 6, wherein said first and second plates have upper and lower edges in respective parallel planes normal to those of said first and second plates, said bluff body being positioned midway between the upper and lower edges of said first and second plates.
ADS:rw
ADS:rw
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8120063 | 1981-06-30 | ||
| GB08120063A GB2101316A (en) | 1981-06-30 | 1981-06-30 | Improvement to vortex flow meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1179869A true CA1179869A (en) | 1984-12-27 |
Family
ID=10522884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000405773A Expired CA1179869A (en) | 1981-06-30 | 1982-06-23 | Vortex flow meter |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1179869A (en) |
| GB (1) | GB2101316A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8613852D0 (en) * | 1986-06-06 | 1986-07-09 | Neptune Measurement Ltd | Vortex shedding body |
| AU4201700A (en) * | 1999-04-06 | 2000-10-23 | Foxboro Company, The | Insertion-type vortex flowmeter |
| US6752027B1 (en) | 1999-04-06 | 2004-06-22 | The Foxboro Company | Vortex flowmeter including removeable and replaceable flow-obstruction element |
| DE10227726A1 (en) * | 2002-06-21 | 2004-01-15 | Invensys Metering Systems Ag | Vortex flowmeter |
-
1981
- 1981-06-30 GB GB08120063A patent/GB2101316A/en not_active Withdrawn
-
1982
- 1982-06-23 CA CA000405773A patent/CA1179869A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2101316A (en) | 1983-01-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |