WO2013013924A1

WO2013013924A1 - Flow rectifier

Info

Publication number: WO2013013924A1
Application number: PCT/EP2012/062407
Authority: WO
Inventors: Hanno Schultheis; Sascha Kamber
Original assignee: Endress+Hauser Flowtec Ag
Priority date: 2011-07-28
Filing date: 2012-06-27
Publication date: 2013-01-31
Also published as: DE102011079993A1; EP2737218A1

Abstract

The invention relates to a flow rectifier comprising a perforated plate (6) having an approximately circular deflector plate, against which a fluid flows in the operating state and which has a diameter D, which perforated plate (6) comprises a first hole having a first diameter d₁, wherein the center of the first hole (1) is in the center of the perforated plate, which perforated plate (6) comprises second holes (2) having a second diameter d₂, wherein the centers of the second holes (2) are located on a first hole circle L₁ around the center of the perforated plate, which perforated plate (6) has third holes (3) comprising a third diameter d₃, wherein the centers of the third holes (3) are located on a second hole circle L₂ around the center of the perforated plate, which perforated plate (6) comprises fourth holes (4) having a fourth diameter d₄, wherein the centers of the fourth holes (4) are located on a third hole circle L₂ around the center of the perforated plate, which perforated plate (6) has fifth holes (5) having a fifth diameter d₅, wherein the centers of the fifth holes (5) are located on a fourth hole circle L₄ around the center of the perforated plate, whereby the following applies: L₁ < L₂ ≤ L₃ < L₄ and d₁ > d₂ > d₃ > d₄ > d₅ and 0,75*d₃ < d₄ and 1,75*L₂> L₃.

Description

Flow straightener

The present invention relates to a flow straightener, in particular a flow straightening plate comprising a perforated plate (6) with a

approximately circular baffle surface, which is flowed in the operating state of a fluid and which has a diameter D and which have a plurality of holes with different diameters.

Flow straighteners have long been known to flow in one

To convert flow with a known flow profile, for example from US 3,840,051, US 5,341,848 or US 5,529,093. Known embodiments are also shown in the article "A new concept of flow conditioner under test" by B. Mickan, G. Pereira, J. Wu and D. Dopheide The object of the invention is to provide an improved flow straightener.

The object is solved by the subject matter of independent claim 1. Further developments and refinements of the invention can be found in the features of the respective dependent claims.

The invention allows numerous embodiments. Some of them will be briefly explained here with reference to the following figures. Identical elements are provided in the figures with the same reference numerals.

1 shows a flow straightener of the prior art,

Fig. 2 shows an embodiment of a flow straightener according to the invention.

In Fig. 1, a common flow straightener is shown. It has become known as "Laws Flow Rectifier." A perforated plate 6 has holes 1, 2, 3 with three different hole diameters, the largest one being at the center of the perforated plate 6. The other holes 2 and 3 are at two arranged concentric hole circles. Fig. 2 illustrates an embodiment of an inventive

Flow rectifier, which comprises a perforated plate 6 with an approximately circular baffle, in plan view and in section. Again, the perforated plate 6 holes 1, 2, 3, 4, 5 on concentric holes around the hole

Center of the perforated plate 6. In operation, the perforated plate 6 is impinged by a fluid which penetrates the holes 1, 2, 3, 4, 5. The perforated plate 6 can be flowed through on its entire diameter P or it is only on a circular section with a diameter D flows, which the

Boundary surface of the perforated plate 6 limited. By the diameter D is thus the

Set center of the baffle, which is in particular the center of the perforated plate 6, as shown here. The center and the diameter D of

Baffle are not extra inscribed in the figure.

In the illustrated embodiment of the invention, the perforated plate has a

Diameter P of 150 mm. It is suitable to be inserted between two flanges of two pipes of a pipeline, for which they have four holes 7 on a further bolt circle K with 125 mm, each with a diameter B. The diameter D of the baffle surface of the perforated plate 6, that is the part of the perforated plate 6, which is flowed by the fluid flowing in the said pipe, is here 54.5 mm. It corresponds to the inner diameter of the pipeline.

The first hole 1 of the perforated plate 6 has a first diameter di, the second holes 2 of the perforated plate 6 each have a second diameter d ₂ , the third holes 3 of the perforated plate 6 each have a third diameter d ₃ , the fourth holes 4 the perforated plate 6 each have a fourth diameter d, and the fifth holes 5 of the perforated plate 6 each have a fifth one

Diameter ds, wherein the center of the first hole 1 in the center of the baffle, which here is the perforated plate 6 is located, the centers of the second holes 2 lie on a first circle hole around the center of the baffle Li, the centers of the third Holes 3 on a second circle of holes L ₂ lie around the center of the baffle surface, the centers of the fourth holes 4 are on a third circle L ₃ around the center of the baffle, and wherein the centers of the fifth holes 5 on a fourth circle hole L ₄ to the

Center of the baffle lie. The holes 1, 2, 3, 4 and 5 are included approximately circular. Also, the diameters d i, d ₂ , d ₃ , d ₄ and ds are not specifically dimensioned in the figure.

The first hole 1 is larger than the second hole 2 - it has a larger diameter di. The second holes 2 have a larger diameter d ₂ than the third holes 3, which in turn have a larger diameter d3 than the fourth holes 4, wherein the fourth holes 4 are again larger than the fifth holes. The following applies to the hole circles: the first circle of holes is the smallest. It thus has the smallest diameter Li and is closest to the center of the baffle. The fourth bolt circle has the largest diameter L ₄ and is furthest from the center of the baffle. The second and the third

Bolt circle lie between the first and fourth bolt circle. They each have a diameter L ₂ and L ₃ , which are each smaller than the diameter L _{4 of} the fourth circle and larger than the diameter of the first circle of holes Li, wherein the diameter L _{3 of} the third circle of holes is equal to or greater than the diameter L _{2 of} the second pitch circle. According to one embodiment of the invention, it is larger and it is L ₂ <L ₃ . Theoretically, the first hole 1 is also located on a fifth circle of holes with a diameter L ₅ = 0.

According to the invention, the diameters d ₃ and d _{4 of} the third and fourth holes 3 and 4 and the diameters L ₂ and L _{3 of} the second and third pitch circle satisfy further conditions: 0.75 ^* d ₃ <d ₄ and 1.75 ^* L ₂ > L ₃ .

In the embodiment sketched here, the perforated plate 6 comprises exactly eighteen fifth holes 5, in each case six fourth, third and second holes 4, 3, 2 and a first hole 1 with D = 54.5 mm and Li = 20 mm and L ₂ = 33 mm and L ₃ = 36 mm and L = 48 mm and di = 9 mm and d ₂ = 8 mm and d ₃ = 7.5 mm and d ₄ = 6 mm and ds = 4 mm. In addition, the thickness T of the perforated plate 6 is 10 mm (T = 10 mm). There are three first straight lines through the center of the first hole and through the centers of two second, fourth and fifth holes. In the case of the drawn six third holes, there are also three second straight lines through the center of the first hole and through the centers of two third holes, with angles of 30 ° to the first straight. For one another, the second straight lines again have an angle of 60 °, just like the first straight lines. All straights through the

Centers of each hole and through the center of the baffle of the perforated plate 6 have the same angle to each other. It could also be spoken of an equal distribution.

In contrast, according to several embodiments of the invention, which are independent of one another but can be combined with one another, the general rule is: 0.25 ^* D <Li <0.50 ^* D and / or 0.50 ^* D <L ₂ <0.75 ^* D and / or 0 , 55 ^* D <L ₃ <0.80 ^* D and / or 0.75 ^* D <L ₄ <1 ^* D and / or 0.15 ^* D <di <0.18 ^* D and / or 0.13 ^* D <d ₂ <0.16 ^* D and / or 0.12 ^* D

<d ₃ <0.15 ^* D and / or 0.09 ^* D <d ₄ <0.13 ^* D and / or 0.06 ^* D <d ₅ <0.09 ^* D and / or 0.15 ^* D <T <0.25 ^* D; with 25 mm <D <250 mm, consequently: 3,75 mm <di <45 mm and / or 3,25 mm <d ₂ <40 mm and / or 3 mm <d ₃ <37,5 mm and / or 2, 25 mm <d ₄ <32.5 mm and / or 1, 5 mm <ds <22.5 mm and / or 6.25 mm <Li <125 mm and / or 12.5 mm <L ₂ <187.5 mm and / or 13.75 mm <L ₃ <200 mm and / or 18.75 mm <L ₄ <250 mm and / or 3 mm <T <62.5 mm. D can also be up to 1500 mm.

Following an embodiment of the invention: 0.34 ^* D <Li <0.39 ^* D and / or 0.58 ^* D <L ₂ <0.63 ^* D and / or 0.63 ^* D <L ₃ <0 , 68 ^* D and / or 0.86 ^* D <L ₄ <0.91 ^* D and / or 0.16 ^* D <di <0.17 ^* D and / or 0.14 ^* D <d ₂ <0 , 15 ^* D and / or 0.13 ^* D <d ₃

<0.14 ^* D and / or 0.10 ^* D <d ₄ <0.12 ^* D and / or 0.07 ^* D <d ₅ <0.08 ^* D and / or 0.17 ^* D <T <0.20 ^* D. A further formed perforated plate 6 has the following relative dimensions: 0.34 ^* D <Li <

0.39 ^* D and 0.58 ^* D <L ₂ <0.63 ^* D and 0.63 ^* D <L ₃ <0.68 ^* D and 0.86 ^* D <L ₄ <0.91 ^* D and 0.16 ^* D <di <0.17 ^* D and 0.14 ^* D <d ₂ <0.15 ^* D and 0.13 ^* D <d ₃ <0.14 ^* D and 0.10 ^* D <d ₄ <0.12 ^* D and 0.07 ^* D <d ₅ <0.08 ^* D. For the thickness T of the perforated plate 6 then: 0.182 ^* D <T <0.184 ^* D. With D = 54, 5 mm, the above-mentioned dimensions of the perforated plate 6 from FIG. 2 result.

In addition, the individual holes at a distance from one another, which is at least 0.001 ^* D, in particular at least 0.1 mm, according to one embodiment even at least 0.5 mm. The distances are between two, the respective hole limiting hole edges. Here, in Fig. 2, the distances between two adjacent first and second holes and two adjacent second and third holes are indicated by a12 and a23. Here applies a12 <a23. All holes do not overlap. A distance of the centers of two holes is thus at least half the sum of their respective diameters added with 0.001 ^* D.

As for the flow straightener according to the figure, a development of the invention, a straight line through the center of the baffle and through the

Center of a third hole 3 at an angle of 10 ° to 50 °, in particular at an angle of exactly 30 °, to a straight line through the center of the baffle and through the center of an adjacent fourth hole 4. Additionally or alternatively, the respective holes 1, 2, 3, 4 and 5 are arranged symmetrically about the center of the circular baffle on the perforated plate 6. The second holes lie, for example, packed hexagonally close to the first hole on the second circle of holes.

According to a further development of the invention, the holes 1, 2, 3, 4 and 5 of the perforated plate 6 each have a chamfer. The holes are sharp-edged, but can also be chamfered on one or both sides, for example by means of a

Cone-lowering drug. The size of the chamfer can be selected depending on the respective hole diameter or is constant for all holes 1, 2, 3, 4 and 5.

The developments are a development of the invention according to the sun

assembled, in particular, the above dimensions are chosen so that a passage area through the baffle formed by the holes, in a ratio greater than 0.5 to the baffle.

A flow straightener according to the invention is e.g. upstream of a flow meter, in particular an industrial flow meter

Process measuring technology, for example, a thermal mass flow meter, used in a pipeline. This use is for example for reducing a so-called inlet length upstream of the flow meter, e.g. after a

Curvature of the pipeline, ie downstream of a bend in the pipeline, meaningful. The length of the distance parallel to the main flow direction of the fluid in the pipeline, usually along the pipe longitudinal axis, between the

Flow equalizer and the flow meter is then for example less than 3 ^* D. The equally sized length of the distance between the end of the pipe bend and the flow straightener is for example less than 5 ^* D. Particularly suitable flow straightener according to the invention in flows in the laminar, transient and turbulent region, especially for gases.

LIST OF REFERENCE NUMBERS

First hole

Second hole

Third hole

Fourth hole

Fifth hole

perforated plate

drilling

Claims

claims

Flow straightener comprising a perforated plate (6) with a

approximately circular baffle surface, which is impinged by a fluid in the operating state and which has a diameter D, which perforated plate (6) has a first hole with a first diameter di,

the center of the first hole (1) being at the center of the circular baffle,

which perforated plate (6) has second holes (2) with a second diameter d ₂ ,

wherein the centers of the second holes (2) lie on a first circle of holes L-i about the center of the circular baffle,

which perforated plate (6) has third holes (3) with a third diameter d3,

wherein the centers of the third holes (3) lie on a second circle of holes L ₂ around the center of the circular baffle,

which perforated plate (6) has fourth holes (4) with a fourth diameter d ₄ ,

wherein the centers of the fourth holes (4) lie on a third circle of holes L ₃ around the center of the circular baffle,

which perforated plate (6) has fifth holes (5) with a fifth diameter ds,

the centers of the fifth holes (5) lie on a fourth circle of holes L ₄ around the center of the circular baffle,

where Li <L ₂ <L ₃ <L ₄ and di> d ₂ > d ₃ > d ₄ > ds and 0.75 * d3 <d ₄ and

1, 75 ^* L ₂ > L ₃ .

2. The flow straightener according to claim 1, wherein: 0.15 ^* D <di <0.18 ^* D and / or 0.13 ^* D <d ₂ <0.16 ^* D and / or 0.12 ^* D <d ₃ <0.15 ^* D and / or 0.09 ^* D <d ₄ <0.13 ^* D and / or 0.06 ^* D <d ₅ <0.09 ^* D.

A flow straightener according to claim 1 or 2, wherein: 0.25 * D <Li <0.50 * D and / or 0.50 * D <L ₂ <0.75 * D and / or 0.55 * D <L ₃ <0.80 * D and / or 0.75 * D <L ₄ <1 * D.

Flow straightener according to any one of claims 1 to 3, wherein the distance between the center is a first and the center of a second hole at least di / 2 + d _2/2 + 0.001 * D and between the center point of a second and the center point of a third hole at least d2 / 2 + ds / 2 + 0.001 * D and between the center point of a third and the center of a fourth hole at least ds / 2 + _d4 / 2 + 0.001 * D and between the center of a fourth and the center of a fifth hole at least d _{the 4/2} + d _5/2 + 0.001 * D.

Flow rectifier according to one of claims 1 to 4, wherein for the thickness T of the perforated plate (6) applies: 0.15 * D <T <0.25 * D.

Flow rectifier according to one of claims 1 to 5, wherein the following applies: 25 mm <D <1500 mm.

A flow straightener according to any one of claims 1 to 6, wherein the number of second holes (2) is equal to the number of third holes (3) and the number of fourth holes (4).

Flow straightener according to one of claims 1 to 7, wherein a straight line through the center of the bolt circle and through the center of a third hole (3) at an angle of 10 ° to 50 ° to a straight line through the

Center of the bolt circle and through the center of an adjacent fourth hole (4).

A flow straightener according to any one of claims 1 to 8, wherein the respective holes (1, 2, 3, 4, 5) are arranged symmetrically about the center of the circular baffle on the perforated plate (6). 1 O. Flow rectifier according to one of claims 1 to 9, wherein the holes (1, 2, 3, 4, 5) of the perforated plate (6) each have a chamfer.

1 1 .The use of a flow straightener according to one of claims 1 to 10, wherein the flow straightener upstream of a

Flow meter is used in a pipeline.

12. Use of a flow straightener according to claim 1 1, wherein the flow straightener is used downstream of a curvature of the pipeline.