MXPA05012862A - Control valve with vortex chambers - Google Patents

Abstract

A fluid flow control valve, especially for severe service, e.g. gas and oil power application, comprises a plurality of vortex chambers (9) through each of which fluid flows in substantially vortex fashion between an inlet channel (8) and a pair of opposed outlets (10, 11). Fluid enters each vortex chamber (9) from its associated inlet channel (8) in a substantially tangential direction wherein it splits into two flowpaths, each having both radial and axial components, leading to respective ones of the outlets (10, 11). The dual vortex outlet arrangement serves to further reduce the noise and erosion problems associated with severe service valves.

Description

IMPROVEMENTS IN FLUID CONTROL DESCRIPTION OF THE INVENTION The present invention is concerned with the control and reduction of fluid pressure in control valves, especially but not exclusively severe service valves for use in energy industries. The most widely used current technology in severe service valves use pressure residence chambers consisting of one or more flow passages containing mutable openings and orifices, labyrinths or multiple abrupt angular turning passages that result in stepped pressure reduction . Alternatively, flow restrictions can be provided by physically reducing the flow passage area through which the fluid passes. As the fluid flows through these physical restrictions, the velocity is increased locally at the restriction outputs generating turbulence that dissipates the energy and reduces the pressure. In the control valves mentioned above, the dissipation of the energy of the flowing fluid is effected by frictional dragging through smooth round passages or by successive abrupt restrictions and expansions through tortuous passages. Some of these arrangements have noise problems associated with them and since they depend on relatively large friction losses, the performance is quite susceptible to viscosity changes which are an inherent result of temperature changes. Another problem associated with these technologies is that the energy dissipated through the physical flow restrictions can result in physical damage or erosion of the valve components if they are not carefully controlled. U.S. Patent Nos. 3,941,350 and 3,780,767 disclose high strength vortex chamber passage cuts for a variable fluid restrictive control valve that offers some noise reduction. With all the vortex camera designs of the prior art, each vortex chamber has only one outlet. In a free vortex spiral flow system, the radial velocity of the fluid increases as it reaches the exit point of the chamber. As the fluid leaves the vortex chamber, the radial velocity is changed into axial velocity and its pressure energy is reduced. With a single output, the energy difference results in turbulence. In extreme cases this will result in cavitations which are detrimental to the performance of the valve, increasing both noise and erosion.

In addition, in the vortex chamber designs of the prior art, the exit point is susceptible to high erosion where the spiral flow hits the bottom side of the exit path which improves the physical barrier that changes the backflow radial to axial flow. It is an object of the present invention to solve or at least mitigate the aforementioned problems associated with the known vortex chamber designs of the control valve. According to the present invention, there is provided a fluid flow control valve of the type including a plurality of vortex chambers through which the fluid flows in an essentially spiral vortex form, each vortex chamber having thus minus one inlet for the fluid and at least two outlets for the fluid. Accordingly, according to the invention, the fluid is introduced under pressure into a vortex chamber via the inlet and into the chamber, the fluid flow is divided in two and takes a generally spiral flow path which has both radial components as axial to each of the outputs which are preferably opposite each other. The radial velocity of the fluid increases with the decreased radius of the spiral flow path, which creates a high back pressure at the vortex chamber inlet and gives the dynamic effect of high fluid resistance. The double outputs offer significant advantages over the previous technique in that the output speed is dramatically reduced and thus is less likely to reach the extreme levels which cause cavitation. Preferably, the inflow is tangential to the outer surface of the vortex chamber, thereby initiating the radial flow path and minimizing any turbulence at the fluid entry point to the vortex chamber and the outlets are positioned on and at the ends opposite of the central axis of the camera. The input flow path can be straight or curved. In a preferred arrangement, the inflow path is of reduced cross-sectional area along the length of the inflow path as described in the co-pending co-pending British patent application entitled "Improvement in fluid control " Preferably, there is only one inlet for the fluid and two outlets for the fluid associated with the vortex chamber, in which case the ratio of the combined cross-sectional area of the two outlets to the cross-sectional area of the inlet is preferably about 2 / 1, although the ratio can be adjusted considerably to produce the desired fluid exit velocity. Preferably, the vortex chamber has the shape of a cylinder or a double conical shape illustrated below. These forms carry out the function of directing the spiral flow towards the exit. However, modifications to those ways to minimize erosion will be apparent to those skilled in the art. Preferably, the trimming of a valve of the invention is of the stacked disc type and the vortex chamber is defined by the disks. The vortex chambers in the disks can be of variable dimension, allowing the level of resistance produced by trimming to the valve's performance profile throughout the actuation stroke of the control valve. Preferably, the vortex chambers are located radially on a disk with a central concentric hole, the fluid inlet and fluid outlet are respectively located on the internal and external diameters of the disk. Each of the disks may consist of one or more elements placed on top of the other with different details machined on or on their surfaces to create the desired geometry of the vortex chambers and the fluid inlet and fluid outlets.

Preferably, the discs are brazed or bonded together by other means to form a stacked disc control member in the form of a cylinder with a concentric bore running along its axis and a plurality of fluid inlets and fluid outlets located on the internal and external surface of the disk stack. Preferably, a plug or plunger is in the central perforation of the disk stack, in such a way that it can cover and expose a variable number of fluid flow paths, with associated pressure reducing chambers, thereby enabling fine reduction control of pressure. Preferably, the outputs of the vortex chamber in a disk stack are in communication with each other. This communication allows an additional subdivision of the fluid flow to the highest vortex chamber in the disk stack above the inlets that are exposed by the plug or plunger. The subdivision of the fluid flow in this way reduces the flow velocity and consequently reduces the noise output. If the valve plug or plunger has risen to its maximum elevation exposing all the vortex entries of the disk stack, the communication between the vortex chambers will become a shock point for the fluid flow passages, reducing the communication of the fluid but forming a shock point that adds additional back pressure or high flow resistances. Finally, the communication between the outputs also eliminates the material in the outflow passage that has the highest potential for erosion in the vortex passage. In a valve of the invention, two or more double outlet vortex chambers can be connected in series with each other, forming by means of a stepped speed control valve, with the two outlets of a vortex chamber being respectively connected to the inlet ports. two of a second series of double output vortex chambers. This pattern can then be repeated to form many cameras in series as desired. In addition, by varying the output cross-sectional area ratio from one series to the next, it is possible to control the expansion of fluid and consequently the velocity of the fluid in the exit orifice and passage. In preferred arrangements, two or three staggered passages provide the majority of the most control valve needs in speed control, but single stage or more than three stage designs can easily be produced with this invention. The communication between the outputs is preferably present with both single-stage and double multi-stage vortex assemblies of the invention. Preferably, the disks in the stack all use the same dual exit vortex chamber design but the combination of two or more double outlet chamber designs can in some cases provide a packing advantage and more adapted performance of the disc that the pressure reduction / plunger displacement curve of a valve can be characterized to suit a particular control requirement. In a preferred arrangement, a double vortex combination described herein is used in conjunction with a tortuous or labyrinth flow path and / or vortex chamber inlet combining the present invention with the known art. This can help to reduce noise, allowing the noise to fully expand in the labyrinth before it leaves the disk. Modes of the invention will now be described by way of example only with reference to the accompanying figures in which: Figure 1 is a vertical section showing the construction of a control valve incorporating a stacked plate stack cutout as is common in the art; Figure 2 and 3 show the construction of a single double outlet vortex chamber of the invention; Figure 4 is a diagram showing the construction of the exit communication in the vortex chambers according to the invention. Figure 5 is a detailed diagram showing the construction of a single-stage double output vortex chamber disc of the invention; Figure 6 is a detailed diagram showing the construction of an alternative construction of a single-stage double outlet vortex chamber according to the invention; Figure 7 is a detailed diagram showing a stacked plate control valve cutout containing a plurality of three stage dual output vortex chamber flow passages according to the invention; Figure 8 is a detailed diagram showing a second alternative construction of a stacked plate control valve cutout containing a plurality of two-stage double exit vortex chamber designs according to the invention; and Figure 9 is a detailed diagram showing a third alternative construction of the stacked plate control valve cutout containing a polarity of three-stage dual output vortex chamber flow passages according to the invention in which the Vortex chambers have been rotated to be placed perpendicular to the plane of the individual disks. Referring to Figure 1, there is shown an example of a disk stack cut-out in a fluid control valve as is common in the art comprising a valve body 1 with an inlet 2 and outlet 3 in fluid communication with each other via a central chamber 4 containing the seat ring 5, disk stack 6 and plug 7. When the valve plug 7 is seated on the valve seat ring 5 the flow is not allowed to pass through the valve. As the plug 7 rises in a controlled motion the flow is allowed to enter the valve through the inlet 2, pass through the disk stack 6 which reduces the flow pressure and out of the outlet 3. Referring to Figures 2 and 3, two modes of the dual exit vortex chamber design are shown in which the flow enters the chamber 9 through the inlet channel 8 substantially tangentially leading to the vortex chamber 9, as shown by the dashed line the input channel can optionally be curved. The fluid flow can undergo many revolutions in the chamber 9 before reaching the outlets 10 and 11. The fluid flow in the vortex chamber fluid passage of high resistance is further characterized because the dissipation of energy is due to a Spiral flow within the vortex chamber as shown by the arrows. In this, as the fluid moves towards the center of the chamber, the concentration of the angular movement requires that its tangential velocity increases. Thus, since the pressure head is dependent on the speed head, there is a pressure distribution. More particularly, the flow field of the vortex cured a pressure drop across the chamber between the inlet and outlets and the effect creates a high back pressure at the inlet of the vortex chamber. This back pressure controls the total flow through the chamber, in such a way that when adding two outlets 11 and 12 to the chamber the total velocity of the fluid leaving the outlets 11 and 12 is reduced. Figure 2 shows a chamber design consisting of a cylinder-shaped chamber and Figure 3 shows a chamber design consisting of a double cone-shaped chamber. Referring to Figure 4, a diagram of the double output vortex chambers is shown in a three-stage series indicating the fluid path communication between the outputs of adjacent chambers. Fluid flow enters the inlets 12 of the first stage vortex chamber and must pass through each first chamber before reaching the double outputs (Figure 2, part 10, 11). Once the flow enters an outlet its flow can take one of two directions, first it can pass to the inlet 13 of the second stage vortex chamber 14 or when only part of the stack is exposed to the inflow, it can pass through an unused first stage vortex chamber and separate the flow in several of the unused second stage vortex chamber inputs. By this means of allowing the flow to be subdivided between the unused chambers the total noise output is reduced as a result of the reduced speed within these subdivided flows. In addition, the communication between two cameras used acts as a virtual barrier instead of a physical barrier to direct the flow of fluid to the entrance of the next stage vortex chamber. As there is no physical barrier, an erosion focal point has been eliminated if the fluid flow has solid particles suspended in the flow. Referring to Figures 2 and 5, a detailed view of a possible construction of a single stage cylindrical double outlet vortex chamber is shown in which the construction is composed of a variety of individual elements, all producible using machining operations or simple stamping. The first element 16 contains the inlet path 8 and the cylindrical chamber 9. The second elements 17 contain a through hole for the fluid leaving the chamber and the third elements 18 to contain the fluid outlet 10 and 11. It will be appreciated that as an autonomous camera an additional piece (not shown) above and below the three elements shown would be required to enclose the exit path of the camera. The elements are joined together to form the single-stage double outlet vortex chamber. Referring to Figures 2 and 6, a detailed view of an alternative design with additional subdivision of the outflow path to reduce noise emission is shown. The first element 19 contains the inlet of the fluid 8 leading to the cylindrical chamber 9. The second elements 20 contain a through hole for the fluid to leave the chamber and subdivided outlet orifices 20a for the flow path. The third elements 21 contain the outlet of the intermediate fluid 21a to pass the flow from the outlet hole to the subdivided outlet orifices. It will be appreciated that as an autonomous camera an additional piece (not shown) above and below the three elements shown would be required to enclose the output paths of the camera. The elements are joined together to form the individual disk. Referring to Figure 7, there is shown a detailed view of a possible construction of a three-stage dual exit vortex chamber passage in which the construction is composed of a variety of individual elements, all producible using machining or stamping operations simple The first element 22 contains an arrangement of vortex chambers with associated input path. The inner ring of the vortex chambers form the first stage inlet and cylindrical vortex chambers 24, the outlets of which communicate with the second stage 26 of the vortex chambers via the passages through the disk 23. The outlets of these second stage vortex chambers communicate with the inputs of the third stage vortexes 25, again through passages in the disk 23. The outputs of the third stage vortex chambers communicate with the output of the disk 27, again via passages on disk 23. The first and third stage vortices are grouped on a common radial line (group 1) and the second stage and exit vortex are grouped on a second common radial line (group 2) equally spaced at the midpoint between the adjacent group 1. As the disk stack is mounted alternating plate elements 22 and 23with plates 22 and 23 form pairs of aligned plates Pl, P2 and adjacent pairs Pl, P2 will be graduated in a pattern grouping to place group 1 of a pair in line with group 2 of the pair below. It will be appreciated that an additional piece (not shown) will be required in the cover of the complete disc of the top and bottom. The elements are joined together to form the complete control valve trimming stack. Referring to Figure 8, there is shown a detailed view of a possible construction of a two-stage dual-output vortex chamber passage in which the construction is composed of a plurality of individual elements 28. This element 28 contains an alternating pattern of three groupings. The first grouping has half the bottom of the conical vortex chamber 29 of first stage entry plus the exit through hole and outlet flow path 30. The second grouping has the entry of the second stage and cylindrical vortex chamber 31. In addition, the third grouping has the upper half of the first stage inlet and chamber 32 of double conical vortex plus the outgoing through hole and outgoing flow path 33. As the disk stack is mounted the element of plate 28 will be graded to a grouping pattern to place grouping 1 in line with grouping 2 of element 28 below and grouping 2 in line with grouping 3 of element 28 below and so on. It will be appreciated that an additional piece (not shown) will be required in the complete disc plugging of the top and bottom. All the elements are joined together to form the complete control valve trimming stack. Referring to Figure 9, there is shown a detailed view of a possible construction of a three stage dual exit vortex chamber passage in which the construction is composed of a variety of individual elements. In this design, the communication between the double output vortex chambers is restricted to a single disk comprising two plates, communication between the disks is not allowed. The first element 34 contains an alternating pattern of two groupings. The first grouping has the first stage entrance and half of the bottom of the first stage cylindrical vortex chamber 36 oriented horizontally plus the entrance of the third stage and half of the bottom of the third stage cylindrical vortex chamber 37 oriented horizontally. The second cluster is the second stage inlet and the second stage cylindrical vortex chamber 38 oriented horizontally plus half the bottom of the exit path 39. The second element 35 contains an alternating pattern of two groupings as well. The first cluster has the upper half of the horizontally oriented first stage cylindrical vortex chamber 36 plus the upper half of the horizontally oriented third stage cylindrical vortex chamber 37. The second cluster is the upper half of the horizontally oriented second stage cylindrical vortex chamber 38 plus the upper half of the exit path 39. As the disk stack is mounted the plate member 34 and 35 must be aligned to match group 1 between the two elements. It will be appreciated that an additional piece (not shown) will be required in the complete clogging of the top and bottom disc. All the elements are joined together to form the complete control valve trimming stack.

Claims (23)

1. CLAIMS 1. A fluid flow control valve of the type that includes a plurality of vortex chambers through which the fluid flows in a substantially spiral vortex manner, characterized in that each vortex chamber has at least one inlet for the fluid and at least two outlets for the fluid.
2. 2. The fluid flow control valve according to claim 1, characterized in that each vortex chamber is arranged in such a way that the fluid introduced under pressure into the chamber via the inlet is divided into two within the vortex chamber. and it takes a generally spiral flow path that has both radial and axial components towards each of the two outputs.
3. 3. The fluid flow control valve according to claim 2, characterized in that the radial velocity of the fluid increases with the decreasing radius of the spiral flow path that creates a high back pressure at the entrance of the vortex chamber and gives the dynamic effect of high fluid resistance.
4. The fluid flow control valve according to any of the preceding claims, characterized in that each vortex chamber has two outputs opposite each other.
5. 5. The fluid flow control valve according to claim 4, characterized in that the inflow is substantially tangential to the external surface of the vortex chamber, thereby initiating the radial flow path and minimizing any turbulence in the point of fluid entry into the vortex chamber.
6. The fluid flow control valve according to claim 4 or claim 5, characterized in that the outlets are positioned on and at opposite ends of a central axis of the chamber.
7. The fluid flow control valve according to any of the preceding claims, characterized in that each vortex chamber has an inlet for the fluid and two outlets for the fluid.
8. The fluid flow control valve according to claim 7, characterized in that the ratio of the combined cross-sectional area of the two outlets to the cross-sectional area of the inlet is about 2/1.
9. 9. The fluid flow control valve according to any of the preceding claims, characterized in that each vortex chamber has the shape of a cylinder.
10. The fluid flow control valve according to any of claims 1 to 8, characterized in that each vortex chamber has a double conical shape.
11. The fluid flow control valve according to any of the preceding claims, characterized in that the valve has a cutout of the stacked disk type and the vortex chambers are defined by the disks.
12. 12. The fluid flow control valve according to claim 11, characterized in that the vortex chambers in the disks can be of variable dimensions allowing the level of resistance produced by the trimming to the valve performance profile throughout. the actuation stroke of the control valve.
13. 13. The fluid flow control valve in accordance with the. claim 11 or 12, characterized in that the vortex chambers are located radially on a disk with a central concentric hole, the fluid inlet and fluid outlet are located in, respectively, the internal and external diameters of the disk.
14. The fluid flow control valve according to any of claims 11 to 13, characterized in that each of the disks consist of one or more elements placed one on top of the other with different details on or on their surfaces to create the desired geometry of the vortex chambers and the fluid inlet and fluid outlets.
15. 15. The fluid flow control valve according to any of claims 11 to 14, characterized in that the discs are joined together to form a disk stack control element in the form of a cylinder with a concentric perforation running along its axis and a plurality of fluid inlets and fluid outlet located on the surfaces internal and external disk stack.
16. 16. The fluid flow control valve according to claim 15, characterized in that a plug or piston is movable in the central perforation of the disk stack, in such a way that it can cover and leave exposed a variable number of trajectories of fluid flow with associated pressure reducing chambers enabling by this the fine control of pressure reduction.
17. 17. The fluid flow control valve according to claim 15 or claim 16, characterized in that the outputs of the vortex chamber in the disk stack are in communication with each other.
18. 18. The fluid flow control valve according to any of claims 15 to 17, characterized in that two or more double outlet vortex chambers are connected in series with each other, thereby forming a stepped speed control valve, with the two outputs of a vortex chamber being connected respectively to the two inputs of a second series of double output vortex chambers.
19. 19. The fluid flow control valve according to any of claims 15 to 18, characterized in that the discs in the stack all use the same double outlet vortex chamber design.
20. 20. The fluid flow control valve according to any of the preceding claims, characterized in that the pressure reduction means are provided at the outlets and / or inlets of the vortex chamber.
21. 21. The fluid flow control valve according to any of the preceding claims, characterized in that labyrinth passages or similar passages are provided in the outlets and / or entrances of the vortex chambers.
22. 22. The fluid flow control valve according to any of the preceding claims, characterized in that the inlet flow path to the vortex chamber is curved.
23. 23. A cutout for a fluid flow control valve, characterized in that it comprises a plurality of vortex chambers as defined in any of claims 1 to 22.