EP3102860A1

EP3102860A1 - Shutter for a rotary adjustment valve

Info

Publication number: EP3102860A1
Application number: EP15705707.6A
Authority: EP
Inventors: Claudio Angelo GATTAVARI
Original assignee: Loclain Srl
Current assignee: OMB VALVES S.P.A.
Priority date: 2014-02-07
Filing date: 2015-01-16
Publication date: 2016-12-14
Also published as: WO2015118420A1

Abstract

A shutter for a rotary valve, comprising: a main body (2) having a conformation that is substantially spheroidal or suitable for rotating about an axis and equipped with a through cavity (3); at least one plate (4) equipped with a plurality of through openings (5) and arranged within the through cavity (3); the plate (4) comprises at least a first layer (41 ) and a second layer (42), each equipped with a plurality of through holes (41 a, 42a); at least some holes (41 a) in the first layer (41 ) at least partially face some holes (42a) in the second layer (42).

Description

Shutter for a rotary adjustment valve

DESCRIPTION

The object of the present invention is a shutter for a rotary valve and a valve comprising this shutter.

The current state of the art in the field of rotary adjustment valves comprises valves known as "Q-Trim" valves. Such valves comprise the presence of one or more perforated plates; normally there is a maximum of seven plates inside the cavity of the spherical shutter or similar shutters. These plates each have a number of openings which can be realized in the form of holes or slits. The purpose of these plates is to divide in various stages the change in pressure that the fluid, be it liquid or gaseous, undergoes as it passes inside the shutter. The greater the number of plates, the greater the number of stages in which the change in pressure will be divided, thereby leading to benefits in terms of noise level, for valves that treat compressible fluids, and in terms of treatment of cavitation, for valves that treat incompressible fluids. The plates can have various geometries customized according to the manufacturer.

The number of holes or slits present in each plate determines the plate's resistance to the fluid and the number of holes or slits is calculated based on process conditions.

Usually, the greater the number of holes, the smaller the diameter of the jet of liquid that flows through an individual hole, lessening also the effect of possible cavitation.

Considering a gaseous fluid, the greater the number of holes, the higher the peak frequency of the valve and the greater the attenuation of the aerodynamic noise level.

These valves are generally based on the following principles: division of the change in pressure into a number of steps, velocity control inside the trim or shutter, division of the confined flow into a number of paths, and increase in peak frequency.

The plates present inside the adjustment member substantially define the trim or shutter of these adjustment valves. The most valuable feature of these valves relates to the fact that the plates are integral with the ball (shutter) and rotate with it. In this manner, they offer greater resistance at low flow rates, at which a greater head is usually required, and minimum resistance when the valve is open/ that is, at higher flow rates, at which the process requires low head loss.

In the event that very severe process conditions arise, usually with very high changes in pressure, the solution presented as yet can be limiting in terms of performance relating to noise level or the attenuation of cavitation. The main problem is the physical limit in the number of plates that can be installed inside a ball, owing to design issues and in order not to sacrifice too much of its maximum capacity (Cv/Kv), which constitutes the true strong point of these valves. Additional devices are often installed on the valve; they are often economical, but they do not always solve the problem.

In many cases, more sophisticated valves need to be adopted, which usually succeed in providing better control of the velocities within the trim, limiting the kinetic energy values that can be reached by the fluid. In this manner, the flow is kept further away from the cavitation limits, for liquids, and the aerodynamic noise due to acceleration of the confined flow is limited, for gases. One example of valves of this type is known from patent no. US 701 1 109.

The principal limit of these solutions lies in the maximum capacity of the valve. The passage is totally or partially obstructed based on the degree of aperture needed to satisfy the process conditions. In any case, even when fully opened, the front cavity of the ball will be such as to markedly reduce the capacity (Cv or Kv) thereof.

By way of example, a valve with DN-100 plates can have a maximum Cv on the order of 500, whereas the Cv of a globe valve, having the same nominal diameter, can reach a maximum Cv of 160-200.

The more sophisticated types of ball valves usually reach comparable or slightly higher Cv values compared to globe valves.

The conformation of the plates has been changed in order to improve the characteristics of the rotary valves equipped with plates. The plates are essentially subjected to deformation, which determines an incurvature thereof. Rolling is the typical deformation process used.

The plates are thus processed by rolling, thereby obtaining a curved conformation with a given radius of curvature. The plates thus obtained can be utilized for treating both compressible fluids and incompressible fluids simply by inverting the concavity thereof with respect to the direction of flow.

In particular, the plates are installed so as to produce a convergence of the jets, in the case in which the fluid is a liquid and it is thus necessary to limit the effects of cavitation. The plates are essentially installed with the concavity facing the opposite side with respect to the direction of flow. In this manner, the adjacent jets of fluid interfere with each other, introducing an additional loss of head. Moreover, they tend to confine any cavitation to a delimited zone, limiting wear of the valve plates.

In the case in which the fluid is a gas and it is thus necessary to attenuate the aerodynamic noise level, the plates are installed so as to produce a divergence of the jets. The plates are essentially installed with the concavity facing the same side as the direction of flow. This configuration allows the jets of fluid exiting the plate to diverge from each other, limiting their interaction and thus reducing the level of noise emitted by the valve. In spite of the fact that the insertion of plates has improved the characteristics of currently available rotary valves, the effects consisting of reduction of cavitation and attenuation of the noise level are often not sufficient to satisfy the most demanding process conditions.

An aim of the present invention is to offer a shutter or trim for a rotary valve that makes it possible to improve the characteristics of the shutters that are currently available.

An advantage of the shutter according to the present invention is that it maintains a high flow coefficient of the valve, substantially equal to the coefficient of flow of currently available valves.

Another advantage of the shutter according to the present invention is that it does not require structural modification of currently available valves. Another advantage of the shutter according to the present invention is that it enables an increase in the peak frequency of the valve in which is installed.

Another advantage of the shutter according to the present invention is that it markedly reduces the impacting sound waves produced by the fluid in transit.

A further advantage of the shutter according to the present invention is that of obtaining a much higher recovery factor FL for the valve in which is installed, compared to shutters of the prior art .

Further characteristics and advantages of the present invention will become more apparent in the following detailed description of an embodiment of the invention at hand, illustrated by way of non-limiting example in the attached figures, of which:

Figure 1 is a schematic view of the shutter according to the present invention, in an open configuration;

Figure 2 shows the shutter of Figure 1 , from a different viewpoint;

Figure 3 is an exploded view of a component of the shutter according to the present invention;

Figure 4 is a section view of the shutter according to the present invention, in an open configuration;

Figure 5 shows the shutter of Figure 4 in a partially open configuration;

Figure 6 shows an alternative embodiment of the shutter according to the present invention, in a closed configuration; Figure 7 shows the shutter of Figure 6 in a partially open configuration;

Figure 8 is a schematic view of a component of the shutter;

Figure 9 is a exploded view of a component of the shutter;

Figure 10 shows an embodiment of the shutter comprising the component of Figure 9, in an open configuration;

Figure 1 1 shows the shutter of Figure 10 in a partially open configuration;

The shutter (1) for a rotary valve according to the present invention comprises a main body (2) of a substantially spheroidal conformation or that is suitable for rotation about an axis, and equipped with a through cavity (3). This through cavity (3) is substantially in the form of a hole provided with a longitudinal axis (X) and afforded through the main body (2). In use, the flow of the fluid to be treated travels through the through cavity (3). During use, the main body (2) can rotate with respect to the body (10) of a valve (V) about an axis of rotation (Y), arranged perpendicular to the longitudinal axis (X). The body (10) of the valve (V) has a first opening (1 1 ) and a second opening (12) designed to be connected to two tracts of a line (P). Preferably, but not necessarily, the first and the second opening (1 1 , 12) are aligned with each other along a longitudinal axis (F) of the line (P) along which the valve (V) is mounted. The shutter (1 ) can rotate between at least one opening position, in which the through cavity (3) puts the first and the second opening (1 1 , 12) in communication, and a closed position, in which the through cavity (3) is not in communication with the first and the second opening (1 1 , 12).

In the preferred embodiment of the valve, the main body (2) can rotate between at least one completely open position, as shown in Figure 3, in which the longitudinal axis (X) is aligned with the longitudinal axis (F) of the line (P) along which the valve (V) comprising the shutter (1 ) is mounted, and a closed position, as shown in Figure 4, in which the through cavity (3) does not face the line (P) along which the valve (V) is mounted. In the closed position, the fluid is substantially intercepted by main body (2) and it cannot pass through the shutter (1 ), in that the through cavity (3) is not in communication with the line.

The shutter further comprises at least one plate (4) equipped with a plurality of through openings (5) and arranged within the through cavity (3). The plate (4) is integral with the main body (2) of the shutter (1). The plate (4) is oriented parallel to the longitudinal axis (X) and to the axis of rotation (Y). In this manner, in the open position of the main body (2), the plate (4) is arranged parallel to the longitudinal axis (F) of the line (P), which also defines the direction of flow, offering the minimum cross- sectional area as an obstacle to the flow. In the intermediate positions between the open position and the closed position, the plate (4) tilts with respect to the direction of flow (F), offering an obstructing cross-sectional area that gradually increases, passing from the open position to the closed position, as can be seen in Figures 4 and 5. In the intermediate positions between the open position and the closed position, the fluid is forced, at least in part, to pass through the through openings (5), dissipating part of its energy.

The plate (4) comprises a first layer (41 ) and a second layer (42), each provided with a plurality of through holes (41 a, 42a).

The through holes (41a) in the first layer (41 ) are preferably not aligned with respect to the through holes (42a) in the second layer (42), so as to create a tortuous path for the fluid. In this case, the first and second layers (41 , 42) are separated by a gap that can be defined by means of a spacer element, for example in the form of a ring or in the form of a metal mesh or perforated metal structure that is preferably deformable so as to adapt to the surfaces of the two layers. In the case of gaseous fluids, the fact that the holes are out of alignment allows for reflection and dampening of part of the aerodynamic noise.

At least some holes (41 a) in the first layer (41 ) can at least partially face some holes (42a) in the second layer (42). The through holes (41a, 42a) at least partially facing each other define the through openings (5) of the plate (4). These through openings (5) define a tortuous path for the fluid, for example because the through holes (41 a, 42a) that face each other are not concentric or because the diameters thereof are different. In these cases, the two plates (41 , 42) can be arranged in contact with each other or spaced apart by means of the interposition of a separator layer.

Preferably, at least some holes (41 a) in the first layer (41 ) face two or more holes (42a) in the second layer (42). This means that the jet of fluid passing through these holes (41 a) from the first layer (41 ) to the second layer (42) divides into at least two additional jets that pass through the holes (42a), further increasing the energy dissipated. Vice versa, the jets of fluid in transit from the second layer (42) towards the first layer (41 ) through these two or more holes (42a) converge in a hole (41 a), dissipating energy in any case. In the preferred embodiment illustrated herein, each hole (41a) in the first layer (41 ) faces one or more holes (42a) in the second layer (42). In particular, each hole (41a) in the first layer (41 ) faces four holes (42a) in the second layer. These four holes (42a) in the second layer (42) are arranged at the vertices of a quadrilateral and the hole (41a) in the first layer (41 ) is arranged in a position that is barycentric thereto. The flow in transit through each hole (41 a) thus divides into four flows that pass through the four holes (42a) in the second layer (42). Vice versa, in flowing from the second layer (42) towards the first layer (41 ), the four streams converge into a single stream through the hole (41a) in the first layer (41 ). This arrangement of the holes (41 a, 42a) in the first and second layers (41 , 42) further increases the energy dissipated by the fluid as it passes through the holes. In any case, the number and arrangement of the holes, as well as the diameter thereof, may vary according to the fluid to be treated and the process conditions. Preferably, the second layer (42) has a larger number of holes (42a) compared to the number of holes (41a) in the first layer (41 ).

In general, if the fluid to be treated is a gas or vapour, the path defined by the openings (41 a, 42a) increases in cross section in the direction of flow, so as to compensate for the increase in the specific volume of the fluid, that is, the decrease in the density of the fluid determined by the drop in pressure. The increase in the cross section of the path defined by the through holes (41 a, 42a) can be obtained for example by increasing the number of through holes in the direction of flow, that is, by having the fluid first pass through the first layer (41 ).

If the fluid to be treated is a liquid, dissipation of energy is achieved by gradually decreasing the number of through holes in the direction of flow, that is, by having the fluid first pass through the second layer (42), keeping the overall cross section (41 a, 42a) of the through holes available for the flow of liquid.

Advantageously, the holes (41 a) in the first layer (41 ) have a countersink (41 b). A wider section of this countersink (41 b) faces the second layer (42). This makes it possible to control the expansion of the gaseous fluid in transit through the first layer (41 ) towards the second layer (42) and to control the convergence of the liquid fluid in transit through the second layer (42) towards the first layer (41 ). In an alternative solution, the holes (41 a) in the first layer (41 ) have at least one cross sectional tract converging towards the second layer (42).

In one particularly advantageous embodiment, the second layer (42) has a folded conformation. As shown in Figure 8, the second layer (42) comprises a plurality of portions (421 ) arranged consecutively with respect to each other. The portions (421 ) are joined one to the other at joining edges (422) that are parallel to the longitudinal axis (X). The portions (421 ) are symmetrically inclined in pairs with respect to horizontal planes passing through the joining edges (422) and they are oriented parallel to the longitudinal axis (X). The through holes (42a) are distributed on portions (4219 of the second layer (42).Two edge portions (423) are joined at the ends of the portions (421 ) of the second layer (42).

In the case of treatment of a gaseous fluid, the plate (4) is arranged so that the fluid first passes through the first layer (41 ) and then through the second layer (42), as in the solution shown in Figure 1 1. In this case, the through holes (41 a) in the first layer (41) converge in the direction of the second layer (42) and are arranged along the joining edges (422) joining the portions (421 ) of the second layer (42). The folded conformation of the second layer (42) is extremely effective in dampening the aerodynamic noise produced by the gaseous fluid passing through the valve.

In the case of treatment of a liquid fluid, the plate (4) is arranged so that the fluid first passes through the second layer (42) and then through the first layer (41 ). In this case, the through holes (41 a) in the first layer converge away from the second layer (42). The folded conformation of the second layer (42) is very effective in reducing the risk of cavitation of the liquid.

The shutter advantageously comprises a third layer (43) equipped with a plurality of through holes (43a).

The through holes (43a) in the third layer (43) are preferably not aligned with respect to the through holes (42a) in the second layer (42). In this case, the two layers (42, 43) are separated by a fourth layer (44), which is described more fully herein below. In this manner, a tortuous path is defined for passage of the fluid. Moreover, in the case of gaseous fluids, the fact that the holes are out of alignment allows for reflection and dampening of part of the aerodynamic noise.

At least some holes (42a) in the second layer (42) can at least partially face some holes (43a) in the third layer (43). In this case, the two layers (42, 43) can be arranged in contact with each other.

In the case of the second and the third layers (42, 43), as in the case of the first and the second layer (41 , 42), the jet of fluid that passes through the holes (42a) from the second (42) to the third layer (43) divides into at least two additional jets that pass through the holes (43a) in the third layer (43), further increasing the energy dissipated. Vice versa, the jets of fluid in transit from the third layer (43) towards the second layer (42) through these two or more holes (43a) converge in a hole (42a), dissipating energy in any case.

In the preferred embodiment illustrated herein, each hole (42a) in the second layer (42) faces one or more holes (43a) in the third layer (42). In particular, each group of four holes (42a) in the second layer (42) faces a group of ten holes (43a) in the third layer (43). Each one of these groups of four holes (42a) in the second layer (42) is arranged in a substantially barycentric position with respect to a group of ten holes (43a) in the third layer (43). The flows in transit through the four holes (42a) thus divide into ten streams that pass through the ten holes (43a) in the third layer (43). Vice versa, in flowing from the third layer (43) towards the second layer (42), the ten streams in transit pass through the ten holes (43a) in the third layer (43) and converge into four streams that pass through the holes (42a) in the second layer (42). This arrangement of the holes (42a, 43a) in the second and third layers (42, 43) further increases the energy dissipated by the fluid as it passes through the holes. In this case as well, the number and arrangement of the holes, as well as the diameter thereof, may in any case vary according to the fluid to be treated and the process conditions. Preferably, the third layer (43) has a larger number of holes (43a) compared to the number of holes (42a) in the second layer (42).

In the embodiment illustrated herein, the first and second layers (41 , 42) are in contact with each other. In other words, the fluid passes through the two layers only through the through holes in each layer. In an alternative embodiment, the first and the second layer could be spaced apart from each other.

In the embodiment illustrated herein, the second and the third layer (42, 43) are spaced apart from each other. For this purpose, the shutter comprising a fourth layer (44), interposed between the second and the third layer (42, 43), is provided with a plurality of through openings (44a), each of which faces at least one hole (42a) in the second layer (42) and at least one hole (43a) in the third layer. The through openings (44a) in the fourth layer (44) preferably have a larger cross section compared to the holes (42a, 43a) in the second and the third layer (42, 43).

As shown in Figures 3, 4 and 5, in a preferred embodiment, each through opening (44a) in the fourth layer (44) has a cross section or area that is larger than the cross section of a group of ten holes (43a) in the third layer and of a group of four holes (42a) in the second layer (42). Each through opening (44a) in the fourth layer (44) is interposed between a group of ten holes (43a) in the third layer (43) and a group of four holes (42a) in the second layer (42). In this manner, each opening (44a) in the fourth layer (44) defines a chamber within which the fluid is free to expand in the passage between the holes (42a, 43a) of the second and the third layers (42, 43), in both directions of flow, thereby further increasing the dissipation of energy. The chamber defined by each opening (44) can be polygonal in cross section, for example hexagonal, as shown in the figure. A polygonal cross section, the shape of which can vary depending upon the case at hand, makes it possible to at least partially abate the impacting sound waves generated by the fluid. In the case of liquids, the openings (44) can also be circular in cross section, in that impacting sound waves are essentially not formed.

In any case, the fourth layer (44) could be omitted and in this case, the second and the third layer (42, 43) can be arranged in contact with each other, or an empty space could be kept between the second and the third layer, interposing a spacer ring therebetween. A solution comprising an empty space is more economical, but offers fewer advantages compared to the solution that comprises a fourth layer (44) as described hereinabove.

The plate (4) could be equipped with additional layers (4), each equipped with openings differing in shape and number.

The use of at least two layers for the realization of the plate (4) offers important advantages. First of all, the presence of at least two layers makes it possible to divide the drop in overall pressure through the plate in at least two stages of smaller proportions. This makes it possible to reduce the noise produced by the fluid as it passes through the plate (4), while also reducing the risk of cavitation on the side downstream of the plate (4). Moreover, the presence of at least two layers does not markedly reduce the maximum capacity of the valve (Cv/Kv).

Advantageously, each one of the described layers (41 , 42, 43, 44) can have a curved conformation. If the various layers are in contact with each other, they will all have a curved conformation. If they are not in contact with each other, one or more layers, but not necessarily all of them, can have a curved conformation.

In the preferred embodiment, the layers (41 , 42, 43, 44) are in contact with each other and they are curved about an axis parallel to the longitudinal axis (X), as can be seen in Figures 1 and 2.

In the case of treatment of a liquid, the plate (4) shall be arranged in such a manner that in the intermediate positions between the open position and the closed position, the concavity shall face the opposite side with respect to the direction of flow. This means that the jets, in which the flow is divided passing through the through openings (5) defined by the holes (41 a, 42a, 43a), converge with each other. Vice versa, in the case of treatment of a vapour or gas, the plate (4) shall be arranged in such a manner that in the intermediate positions between the open position and the closed position, the concavity shall face the same side, with respect to the direction of flow. This means that the jets in which the flow is divided, diverge from each other as they pass through the through openings (5) defined by the holes (41 a, 42a, 43a).

The illustrated embodiment of the shutter comprises two plates (4) of the type described herein. In other embodiments, the shutter may be equipped with only one plate (4) or with more than two plates (4).

The main body (2) of the shutter (1 ) can be provided with a lateral opening (21 ) that opens into the through cavity (3). This lateral opening (21 ) has a longitudinal axis (Z) perpendicular to the longitudinal axis (X) of the through cavity (3) and to the axis of rotation (Y) of the main body (2). As can be seen in Figure 7, in an intermediate opening position of the shutter (1 ), the lateral opening (21 ) faces the outflow line (P) from the valve (V). The lateral opening (21 ) is advantageous in the case of gaseous fluids, in that with limited openings of the shutter, the fluid increases in specific volume and it therefore requires a passage area for outflow from the ball that is larger than the inflow area.

Claims

1 . A shutter for a rotary valve, comprising: a main body (2), having a substantially spheroidal conformation and equipped with a through cavity (3) having a longitudinal axis (X); at least one plate (4), equipped with a plurality of through openings (5) and arranged within the through cavity (3); characterised in that: the plate (4) is arranged parallel to the longitudinal axis (X); the plate (4) comprises a first layer (41 ) and a second layer (42), each equipped with a plurality of through holes (41 a, 42a).

2. The shutter according to claim 1 , wherein the through holes (41a) in the first layer (41 ) are disaligned with respect to the through holes (42a) in the second layer (42).

3. The shutter according to claim 1 , wherein at least some holes (41 a) in the first layer (41 ) are at least partially facing some holes (42a) in the second layer (42).

4. The shutter according to claim 1 , wherein at least some holes (41 a) in the first layer (41 ) are facing two or more holes (42a) in the second layer

(42) .

5. The shutter according to claim 1 , wherein each hole (41a) in the first layer (41 ) is facing one or more holes (42a) in the second layer (42).

6. The shutter according to claim 1 , comprising a third layer (43) equipped with a plurality of through holes (43a); at least some holes (42a) in the second layer (42) are at least partially facing some holes (43a) in the third layer (43).

7. The shutter according to claim 6, wherein the through holes (42a) in the second layer (42) are disaligned with respect to the through holes (43a) in the third layer (43).

8. The shutter according to claim 6, wherein at least some holes (42a) in the second layer (42) are facing two or more holes (43a) in the third layer

(43) .

9. The shutter according to claim 6, wherein each hole (42a) in the second layer (42) is facing one or more holes (43a) in the third layer (43).

10. The shutter according to claim 1 , wherein the second layer (42) has a higher number of holes (42a) than the number of holes (41 a) in the first layer (41 ).

1 1. The shutter according to claim 6, wherein the third layer (43) has a higher number of holes (43a) than the number of holes (42a) in the second layer (42).

12. The shutter according to claim 1 , wherein the holes (41 a) in the first layer (41 ) have a countersink (41 b); a wider section of such countersink (41 b) is facing the second layer (42).

13. The shutter according to claim 1 , wherein the first and the second layer (41 ,42) are in contact with each other.

14. The shutter according to claim 6, wherein the second and the third layer (42,43) are in contact with each other.

15. The shutter according to claim 6, wherein the second and the third layer (42,43) are spaced out from each other.

16. The shutter according to claim 6, comprising a fourth layer (44), interposed between the second and the third layer (42,43), which is provided with a plurality of through openings (44a), each of which is facing at least one hole (42a) in the second layer (42) and at least one hole (43a) in the third layer.

17. The shutter according to claim 16, wherein the through openings (44a) in the fourth layer (44) have a larger section than the holes (42a,43a) in the second and third layer (42,43).

18. The shutter according to claim 1 , wherein the first and/or the second layer (41 ,42) have a curved conformation.

19. The shutter according to claim 16, wherein the third layer (43) and/or the fourth layer (44) have a curved conformation.

20. An adjustment valve comprising: a body (10), equipped with a first opening (1 1 ) and a second opening (12); a shutter (1 ) according to one of the preceding claims, arranged within the body (10) and rotatable with respect to the body (10) about an axis of rotation (Y), arranged perpendicular to the longitudinal axis (X) of the through cavity (3); the shutter (1 ) can rotate between at least one opening position, in which the through cavity (3) puts the first and the second opening (1 1 ,12) in communication, and a closed position, in which the through cavity (3) is not in communication with the first and the second opening (1 1 ,12).