Valve Assembly

Abstract

A valve assembly for controlling the flow of a fluid therethrough includes an inlet for receiving a fluid, a cage in fluid connection with the inlet, and a plug. The cage includes a first portion including a first port arranged in a wall of the cage for allowing fluid flow therethrough in a first mode of operation, and a second portion including a second port arranged in a wall of the cage for allowing fluid flow therethrough in a second mode of operation. The second port is arranged to increase turbulation when the fluid flows through the second port in the second mode of operation relative to when the fluid flows through the first port in the first mode of operation. The plug is arranged to cooperate with, and be moveable relative to, the cage between the first and second modes of operation.

Claims

1. A valve assembly for controlling the flow of a fluid therethrough, comprising: an inlet for receiving a fluid; a cage in fluid connection with the inlet, the cage comprising: a first portion comprising a first port arranged in a wall of the cage for allowing fluid flow therethrough in a first mode of operation; and a second portion comprising a second port arranged in a wall of the cage for allowing fluid flow therethrough in a second mode of operation, wherein the second port is arranged to increase turbulation when the fluid flows through the second port in the second mode of operation relative to when the fluid flows through the first port in the first mode of operation; and a plug arranged to cooperate with, and be moveable relative to, the cage between the first and second modes of operation.

2. The valve assembly of claim 1, wherein in the first mode of operation the turbulence intensity of the fluid flowing through the valve assembly is 5% or less and/or wherein in the second mode of operation the turbulence intensity of the fluid flowing through the valve assembly is 15% or more.

3. The valve assembly of claim 1, wherein the second port is different in size and/or shape to the first port.

4. The valve assembly of claim 1, wherein the second port is arranged tangentially with respect to the wall of the cage.

5. The valve assembly of claim 1, wherein the first port is arranged perpendicular with respect to the wall of the cage.

6. The valve assembly of claim 1, wherein the second port is curved.

7. The valve assembly of claim 1, wherein the first port is straight.

8. The valve assembly of claim 1, wherein the second port comprises a nozzle shaped structure.

9. The valve assembly of claim 1, wherein the diameter of the second port narrows in the direction of fluid flow therethrough.

10. The valve assembly of claim 1, wherein the second port is arranged to separate the flow of fluid therethrough into a plurality of smaller streams.

11. The valve assembly of claim 1, wherein the second port comprises one or more baffles.

12. The valve assembly of claim 1, wherein the first portion comprises a plurality of first ports.

13. The valve assembly of claim 1, wherein the second portion comprises a plurality of second ports.

14. The valve assembly of claim 1, wherein the plug is arranged concentrically with respect to the cage.

15. The valve assembly of claim 1, wherein the plug is arranged inside the cage.

16. The valve assembly of claim 1, wherein the plug is arranged outside the cage.

17. The valve assembly of claim 1, wherein the plug is arranged to be moved linearly relative to the cage.

18. The valve assembly of claim 1, wherein the plug is arranged to be moved rotatably relative to the cage.

19. The valve assembly of claim 1, wherein the plug comprises a peripheral wall arranged to engage with the cage, the peripheral wall comprising: a first portion comprising a first port arranged in the peripheral wall for allowing fluid flow therethrough in the first mode of operation; and a second portion comprising a second port arranged in the peripheral wall for allowing fluid flow therethrough in the second mode of operation; wherein in the first mode of operation, the first port of the peripheral wall is at least partially aligned with the first port of the cage; and wherein in the second mode of operation, the second port of the peripheral wall is at least partially aligned with the second port of the cage.

20. The valve assembly of claim 19, wherein the first port of the peripheral wall is the same shape and/or size as the first port of the cage, and/or wherein the second port of the peripheral wall is the same shape and/or size as the second port of the cage.

21. The valve assembly of claim 1, comprising an outlet in fluid connection with the cage for discharging fluid from the valve assembly.

22. A system for storing energy comprising the valve assembly of claim 1.

23. The system of claim 22, being a pumped hydro storage (PHS) system.

24. The system of claim 23, comprising: upper and lower reservoirs; a working fluid; and a conduit arranged to permit flow of the working fluid from the upper reservoir to the lower reservoir under gravity, the conduit comprising a turbine generator arranged to be driven by the flow of the working fluid through the conduit to generate energy.

25. The system of claim 24, wherein the valve assembly is arranged in the conduit, optionally wherein the valve assembly is arranged in the conduit between the upper reservoir and the turbine generator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0066] FIG. 1 illustrates a perspective sectional view of a valve assembly for controlling the flow of a fluid therethrough in accordance with a first embodiment of the invention;

[0067] FIG. 2A illustrates a perspective view of a cage of a valve assembly in accordance with a first embodiment of the invention;

[0068] FIG. 2B illustrates a partial perspective view of the cage of a valve assembly in accordance with a first embodiment of the invention;

[0069] FIG. 3A illustrates a cross-sectional view of the cage along a plane A of FIG. 2B;

[0070] FIG. 3B illustrates a cross-sectional view of the cage along a plane B of FIG. 2B;

[0071] FIGS. 4A to 4C illustrate different mode of operations of a valve assembly in accordance with a first embodiment of the invention;

[0072] FIGS. 5A to 5C illustrate perspective views of a cage and plug in accordance with a second embodiment of the invention in different modes of operation; and

[0073] FIG. 6 illustrates a system for storing energy comprising a valve assembly in accordance with a first embodiment of the invention.

DETAILED DESCRIPTION

[0074] FIG. 1 shows a perspective sectional view of a valve assembly 100 for controlling the flow of a fluid therethrough in accordance with a first embodiment of the invention. The valve assembly 100 comprises an inlet 102 for receiving a fluid. The valve assembly 100 further comprises a cylindrical cage 104 in fluid connection with the inlet 102. Additionally, the valve assembly 100 has an outlet 110 for discharging fluid from the valve assembly 100.

[0075] The lower half of the cage 104 defines a first portion 104A comprising a plurality of first ports 106A arranged in a wall 105 of the cage 104 for allowing fluid flow therethrough. The upper half of the cage 104 defines a second portion 104B comprising a plurality of second ports 106B arranged in the wall 105 of the cage 104 for allowing fluid flow therethrough. The plurality of second ports 106B are arranged to increase turbulation of the fluid when it flows through the plurality of second ports 106B compared to when it flows through the plurality of first ports 106A, as will be explained in more detail below.

[0076] The valve assembly 100 further comprises a cylindrical plug 108 arranged inside the cage 104. In an initial position (i.e. the off or closed position), the plug 108 abuts both the first and second portions 104A, 104B of the cage 104, thereby preventing the flow of fluid through the valve assembly 100.

[0077] In a first mode of operation (i.e. control mode), the plug is moved upwards from the initial position to a first position in which it abuts only the second portion 104B of the cage 104. In this way, fluid is able to flow through the plurality of first ports 106A, but not through the plurality of second ports 106B.

[0078] In a second mode of operation (i.e. enhanced mixing mode), the plug is moved upwards from the first position to a second position in which it no longer abuts the cage 104, and so does not abut either of the first and second portions 104A, 140B. In this way, fluid is able to flow through both the plurality of first and ports 106A and the plurality of second ports 106B, thereby increasing turbulation of the fluid flowing through valve assembly 100 in the second mode of operation relative to in the first mode of operation.

[0079] FIGS. 2A and 2B illustrate perspective views of the cage 104 employed in the valve assembly 100. FIGS. 3A and 3B illustrate cross-sectional views of the cage 104 along planes A and a plane B of FIG. 2B respectively. The cage 104 has a wall 105 defining an elongate cylinder. The lower half of the cylinder defines the first portion 104A of the cage 104 and the upper half of the cylinder defines the second portion 104B.

[0080] The first portion 104A comprises a plurality of first ports 106A that pass through the wall 105 of the cage 104 for allowing fluid flow therethrough in the first mode of operation. Each of the plurality of first ports 106A is straight (i.e. follows a linear path through the wall 105) and is arranged generally perpendicular (i.e. about) 90 with respect to the wall 105 at the point through which it passes.

[0081] The second portion 104B comprises a plurality of second ports 106B that pass through the wall 105 of the cage 104 for allowing fluid flow therethrough in the second mode of operation. Each of the plurality of second ports 106B is arranged tangentially with respect to the wall 105 of the cage 104. In this way, the plurality of second ports 106B advantageously induce swirling of fluid flowing through the valve assembly 100 in the second mode of operation. This increases turbulation of the fluid flowing through valve assembly 100 in the second mode of operation relative to in the first mode of operation.

[0082] FIGS. 4A to 4D illustrate different modes of operation of the valve assembly 100. Translational movement of the plug 108 inside the cage 104 allows the different modes of operation to be implemented.

[0083] FIG. 4A shows a first (i.e. control) mode of operation, in which the plug 108 covers the plurality of second ports 106B, but does not cover the plurality of first ports 106A. In this way, fluid is able to flow through the plurality of first ports 106A, but not through the plurality of second ports 106B. Since each of the plurality of first ports 106A are straight and arranged generally perpendicular with respect to the wall 105, turbulation of the fluid passing through the plurality of first ports 106A is minimised. The first mode of operation therefore provides for controlled flow of the fluid through the valve assembly 100. Thus, in the first mode of operation, the valve assembly 100 behaves similarly to a conventional fluid control valve.

[0084] FIGS. 4B and 4C show two different ways in which the second (i.e. enhanced mixing) mode of operation can be implemented. Referring to FIG. 4B, the second mode of operation can be implemented in a first way by translational movement of the plug 108 to a position in which the plug 108 covers the plurality first ports 106A, but does not cover the plurality of second ports 106B. Referring to FIG. 4C, the second mode of operation may be implemented in a second way by translational movement of the plug 108 to a position in which the plug 108 is no longer inside the cage 104, and so does not cover either of the plurality of first and second ports 106A, 106B (as was described above in relation to FIG. 1).

[0085] Since each of the plurality of second ports 106B is arranged tangentially with respect to the wall 105 of the cage 104, the second ports 106B induce swirling of fluid flowing through the valve assembly 100 with respect to fluid flowing through the plurality of first ports 106A. The plurality of second ports 106B therefore increases turbulation of the fluid flowing through the plurality of second ports 106B compared to when the fluid flows through the plurality of first ports 106A. Thus, turbulation of the fluid flowing through the valve assembly 100 is increased in the second mode of operation relative to in the first mode of operation.

[0086] FIG. 4C shows a third (i.e. off or closed) mode of operation, in which the plug is arranged to cover both the plurality first ports 106A and the plurality of second ports 106B, thereby prohibiting the flow of fluid through the valve assembly 100.

[0087] FIGS. 5A to 5C illustrate perspective views of a plug 502 and a cage 504 arrangement 500 in accordance with a second embodiment of the invention. The plug 502 is arranged concentrically outside of the cage 504 such that it can be moved rotatably relative to the cage 504 to provide different modes of operation of the arrangement 500.

[0088] The lower half of the cage 504 defines a first portion 504A comprising a plurality of first ports 506A arranged in a wall 505 of the cage 504 for allowing fluid flow therethrough. The upper half of the cage 504 defines a second portion 504B comprising a plurality of second ports 506B arranged in the wall 505 of the cage 504 for allowing fluid flow therethrough. The plurality of first ports 506A are straight and arranged generally perpendicular with respect to the wall 505. The plurality of second ports 506B are arranged tangentially with respect to the wall 505. In this way, the plurality of second ports 506B increase turbulation of a fluid flowing therethrough relative to the plurality of first ports 506A.

[0089] The plug 502 comprises a peripheral wall 508 arranged to engage with the cage 504. The lower half of the peripheral wall 508 defines a first portion 508A comprising a plurality of first ports 510A that pass through the plug 502, for allowing fluid flow therethrough in a first mode of operation. The upper half of the peripheral wall 508 defines a second portion 508B comprising a plurality of second ports 510B that pass through the plug 502, for allowing fluid flow therethrough in a second mode of operation. The plurality of first ports 510A are straight and arranged generally perpendicular with respect to the peripheral wall 508. The plurality of second ports 510B are arranged tangentially with respect to the peripheral wall 508. In this way, the plurality of second ports 510B increase turbulation of a fluid flowing therethrough relative to the plurality of first ports 510A.

[0090] As shown in FIG. 5A, in a first (i.e. control) mode of operation, the plurality of first ports 510A of the peripheral wall 508 are aligned with the plurality of first ports 506A of the cage 504. In the first mode of operation, the plurality of second ports 510B of the peripheral wall 508 are out of alignment with the plurality of second ports 506B of the cage 504. Thus, in the first mode of operation, fluid is able to flow through the plurality of first ports 506A, but is prevented from flowing through the plurality of second ports 506B.

[0091] As shown in FIG. 5B, in a second (i.e. enhanced mixing) mode of operation, the plurality of first ports 510A of the peripheral wall 508 are out of alignment with the plurality of first ports 506A of the cage 504. In the second mode of operation, the plurality of second ports 510B of the peripheral wall 508 are aligned with the plurality of second ports 506B of the cage 504. Thus, in the second mode of operation, fluid is able to flow through the plurality of second ports 506B, but is prevented from flowing through the plurality of first ports 506A. Therefore, turbulation of the fluid flowing through the plug 502 and cage 504 arrangement 500 is increased in the second mode of operation relative to the first mode of operation.

[0092] FIG. 5C shows the plug 502 and cage 504 arrangement 500 in a third (i.e. off or closed) mode of operation, in which both the plurality of first ports 506A and plurality of second ports 506B of the cage 504 are out of alignment with the plurality of first ports 510A and plurality of second ports 510B of the peripheral wall 508. Thus, in the third mode of operation, the flow of fluid through the plug 502 and cage 504 arrangement 500 is completely blocked.

[0093] Referring to FIG. 6, a system 600 for storing energy comprising a valve assembly 100 according to a first embodiment of the invention has upper and lower reservoirs 602, 604 connected by an underground conduit 606. The conduit 606 feeds in and out of a penstock 608, which houses a turbine 612 of a turbine generator 610. The turbine generator 610 also comprises a generator unit 616 situated directly above the penstock 608. The turbine generator 610 further comprises a shaft 614, which extends vertically upwards from and connects the turbine 612 to the generator unit 616. The valve assembly 100 is situated in the conduit 606 between the upper reservoir 602 and the penstock 608. The upper and lower reservoirs 602, 604 and the conduit 606 contain a working fluid 620. In this particular example, the working fluid 620 is a slurry comprising a suspension of mineral particles and a surfactant in water.

[0094] During times of low on-grid electricity demand, or when there is an excess of electricity on-grid, the turbine 612 may be driven in reverse using electrical energy to pump the working fluid 620 through the conduit 606 from the lower reservoir 604 to the upper reservoir 602. In this way, the working fluid 620 gains potential energy. The working fluid 620 may be stored in the upper reservoir 602 until such time that the system 600 is required to generate energy, for example, at times of high on-grid electricity demand. At such times, the working fluid 620 is allowed to flow back through the conduit 606 from the upper reservoir 602 to the lower reservoir 604 through the penstock 608. The flow of the working fluid 620 through the penstock 608 rotates the turbine 612 and the shaft 614, thereby resulting in the generation of electrical energy by the generator unit 616. This electrical energy may then be sent to the electricity grid (not shown in FIG. 6) to help meet the high electricity demand.

[0095] When the system 600 is in frequent use, due to the continuous movement of the working fluid 620 between the upper and lower reservoirs 602, 604, the working fluid 620 will be sufficiently mixed to provide the desired rheological properties (for example, such as viscosity). At such times, the valve assembly 100 can be used in the first mode of operation (i.e. control mode). This may advantageously permit flow of the working fluid 620 through the valve assembly 100 with minimal turbulation, thereby having minimal impact on the performance of the turbine generator 610 to generate energy.

[0096] When settling and sedimentation of the working fluid 620 has occurred, for example if the working fluid 620 has remained stationary in the upper reservoir 602 for a significant period of time, the valve assembly 100 can be used in the second mode of operation (i.e. enhanced mixing mode) to intentionally turbulate the working fluid 620 fluid as it flows therethrough. Such turbulation by the valve assembly 100 may advantageously restore the desired rheological properties of the working fluid 620.