Programmable pressure reducing apparatus for throttling fluids under high pressure

Abstract: Programmable pressure reducing apparatus for throttling fluids under high energy in which standardized parts can be stacked and nested to achieve a wide range of restriction and expansion points interposed in tortuous fluid flow paths which divide and recombine the fluid a plurality of times to dissipate high energy without incurring cavitation.

Description: The invention relates to a multi-stage programmable pressure reducing apparatus for high energy fluids consisting of a plurality of close-fitting concentric cylindrical first and second sleeves, each of the sleeves being provided with a plurality of radial fluid passages, spaced across the cylindrical surfaces of the sleeves in a desired pattern, the sleeves being rotated, one relative to the other in such a way that the radial fluid passages provide a plurality of labyrinthine fluid flow paths from the outside to the inside of the sleeves. Such pressure reducing apparatus is known from US-A-4,249,574, wherein tortuous flow paths through many expansion chambers and restricting orifices are present to create multi-stage dissipation of the energy. The dissipating element in this known throttling valve comprises nested and drilled relatively rotatable cylinders or sleeves, in which the holes are critically placed for fractional overlapping. The thus created flow paths are planar, that is two dimensional in the circumferential direction of the dissipating element. A certain degree of adjustability exists in that the degree of fractional overlapping of the holes can be changed by rotating the sleeves in relation to one another. The flexibility of this known apparatus is therefore limited. It is an object of the invention to provide an apparatus of the type described, in which an almost limitless pressure profile can be created at every stage of the pressure drop, the number of pressure drop stages can be varied as desired at substantial savings in part costs and a third dimension can be added to the fluid flow pattern. According to the invention this object is achieved by providing an apparatus wherein the first sleeve is a cylindrical support sleeve having a plurality of axially spaced apart tiers of the circumferentially spaced apart radial fluid passages, the second sleeves consist of a plurality of pressure dropping, staging rings adapted to be carried concentrically by the first sleeve stacked in tiers of nested, staging rings of progressively differing diameters to establish a plurality of pressure dropping stages, each ring having annular walls extending radially and axially to define at least a portion of an annular fluid flow channel, the axially extending wall (21) of each ring having a plurality of the circumferentially spaced apart radial fluid passages communicating with its annular fluid flow channel, said staging rings proximate to the first sleeve being axially adjustable to bring their respective annular fluid flow channels into variably adjustable register with one corresponding array of the circumferentially spaced apart radial passages (14) in the first sleeve, the nested rings being relatively axially adjustable to bring their respective annular channels into variably adjustable register to establish pressure dropping stages of selectable size, and programming spacer means, comprising a programming disc arranged above the first tier of staging rings and/or between tiers of below the first tier, said programming disc adjusting the degree of axial registration of the respective annular flow paths of the staging rings in subsequent tiers with the proximate radial fluid flow passages and having a configuration which enables a different degree of axial registration for each pressure dropping stage, and means to secure the staging rings in fixed operating relationship, whereby the fluid flow from the high pressure side to the low pressure side will cause the flow to split and contract at the radial passages, to recombine in the annular flow paths with associated impingement and frictional losses and to change directions both circumferentially and axially, and whereby the pressure profiles at all stages of pressure reduction can be programmed by said spacer means. By assembling the second or interior sleeves from tiers of nested and slotted staging rings in variable numbers the design criteria of the throttling valve as to the number of stages of pressure reduction and the volume requirements of each stage can be matched. The flow path in the circumferential direction is lengthened by the annular fluid flow channels in each ring and an adjustable third dimension of this flow path in the axial direction is added by the arrangement of one or more programming discs. It is observed that from US-A-4,429,714 it is known to assemble a flow dividing trim cage from stacked plates, spaced by dependent legs, annular wire screens being arranged in the spaces between adjacent plates. This apparatus only provides a one stage pressure drop, the only possibility for adjusting the pressure profile being the replacement of the wire screens between adjacent plates. Other features of the apparatus according to the invention are defined in the subclaims. Embodiments of the apparatus according to the invention will now be described with reference to the drawing, in which Figure 1 is a view in vertical section of the seat and disc of a valve embodying the programmable pressure reducing assembly of the present invention; Figure 2 is a view in enlarged scale and in vertical section of one half of a programmable pressure reducer illustrating both 2 and 3 stages of pressure drop and two tiers of reducers of differing depths and programming; Figure 3A is a fragmentary view in vertical section along a staggered section line of 3 tiers of a 5-stage reducer illustrating flow direction changes along the Z axis; Figure 3B is a fragmentary view in horizontal section of 5 stages of pressure reduction corresponding to Figure 3A and showing flow direction changes in the X-Y plane; Figure 4 is a plan view of one basic staging ring configuration; and Figure 5 is a view in vertical section taken on the line 5-5 of Figure 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Referring to Figures 1 and 2, there is shown a movable valve disc 10 having a seating surface 11 adapted to engage a fixed seat 12. Carried by the lower end of the disc 10 is a cylindrical sleeve 13 formed with five tiers of circumferentially arrayed fluid passages 14, preferably drilled. In the illustrated embodiment there are 8 equally circumferentially spaced passages 14 in each tier. The disc 10 is shown engaged with its seat 12 to shield all tiers of passages from the high pressure side of the valve, but as the valve lifts (Fig. 2) the tiers are progressively exposed to the flow. Mounted in the sleeve 13 is a programming ring 15, described more fully below, and five concentric and nested staging rings. In Fig. 2 which is in enlarged scale and simplified as to the numbers of elements there is shown two staging rings 16a and 17a in the first tier, two rings 16b and 17b in the second tier, two rings 16c and 17c in the third tier, and single rings 16d and 16e in the fourth and fifth tiers, respectively. The staging rings are broken away at the center to show the inside of sleeve 13 and one of the passages 14 in each. The assembly is completed by a composite disc 18 in Fig. 1 and 24 in Fig. 2. With parts arranged in their correct axial and circumferential spacings, all as described below, to establish the desired pressure profile, the parts are secured in position, preferably by brazing, to seal all leakage flow paths between mating surfaces. It will be understood that by substituting discs with different numbers of tiers and stages and differently programmed axial placements, the same valve can be made to accommodate different flow volumes at different pressures and also accommodate different fluids, compressible and incompressible. Referring to Figures 4 and 5, there is shown the configuration of a typical staging ring 16. The ring is formed with annular fluid flow channel 20 defined by an axially extending wall 21 and an upper radially extending wall 22. The cross section of the ring is essentially square with the lower outside corner portion removed to form the fluid channel 20, which when the system is in operation will constitute an expansion volume. The axially extending wall is formed with slots 23 which define constriction passages which vent the annular fluid channel radially inwardly. For convenience and efficiency of machining the slots 23 are at diametrically spaced points, and preferably a complete tier of nested rings may be slotted at the same time. The widths and numbers of the slots is predetermined by calculation. In the illustrated embodiment, there are 8 equally spaced slots, the centers of which are at 45° intervals. The staging rings of any given stage of pressure reduction will be identical in size and geometry. Referring to Figure 2, there is shown a 3 stage assembly for tiers 1-3 and two (2) stages for tiers 4 and 5 in which the second and third stages are axially programmed differently. As in Fig. 1, the stages are all nested within the apertured cylindrical sleeve 13 carried at the end of the disc 10, which is shown fully raised from the seat 12. The free end of the sleeve 13 carries an extension 13a which with the valve open fits within the lower portion 12a of the seat 12 with slight clearance 30 through which fluid under pressure flows at high and potentially damaging velocity. To prevent damage the extension is formed with a series of expansion chambers 30a, b and c in the form of circular grooves which dissipate the fluid energy as the flow cascades through the chambers. The program disc 15 contains 2 steps 15a and 15b for stages 1 and 2 respectively against which are seated the nested staging rings 16a and 17a. The step 15a in the programming ring 15 causes the annular fluid channel 20 in the staging ring 16a to move out of full alignment or register with the fluid passage 14 in the sleeve 13, thus eclipsing the passage for, say, one half of its area. The next two staging tiers 16b and 16c below the ring 16a will be identically displaced to establish identical throttling passages. A supplemental or secondary programming disk 25 between the staging rings 16c and 16d establishes a further axial displacement below and thus provides further constriction at the interface between the fluid passage 14 and the annular flow channels 20. A composite disc 24 brazed in position terminates the stack comprising stage 1. The step 15b on the programming ring 15, shorter than the step 15a, positions the staging ring 17a slightly upwardly and therefore slightly out of full registration with a radial passage or slot 23 formed in the proximate axially extending wall 21 of the ring 16a, thus forming a constriction which is larger than that between the fluid passage 14 in the sleeve 13 and the annular channel 20 of the staging ring 16a. In addition the staging ring 17a is rotated to place its radial passages or slots 23 exactly half way between each pair of corresponding slots 23 in the ring 16a (in the manner shown in Figures 3A and 3B). The stacked rings 17b and 17c of stage 2 are also positioned axially by the step 15b of the program disc 15 in the same relationship to their outwardly nested rings as mating rings 16b, 16c. Thus completing tiers 2 and 3 for stage 2. The circumferential positioning of the slots is also identical, thus ensuring equal division of the fluid flow paths, all as described below. The composite disc 25 secures the stacked rings of stage 2. The entire assembly is brazed at all contiguous surfaces to integrate the structure and prevent by-pass leakage. As a result tiers 1-3 have profiles different than tiers 4 and 5 at the same radial location. The examples of programming by the discs 15 and 25 and of providing different numbers of elements in the tiers of the respective stages is intended to be illustrative of how the invention can be used to achieve an extensive number of different pressure profiles in the fluid flow through the system as the valve opens and is not, therefore, intended to represent a practical operating system. Inherent in all systems, however, is the splitting, recombining, contracting, impinging, frictionally dissipating, expanding and turning of the flow paths to provide an extremely tortuous path able to control cavitation, noise, and erosion at extremely high energy levels. These flow paths, in a typical system are best seen having reference to Figures 3, 3A and 3B. In the arrangement of Figure 3 assembly parts corresponding to Figure 1 are identified by like reference numerals. The assembly differs by the addition of two more staging rings 26 a, b, c, d and e and 27 a, b, c, d and e. This adds 2 more stages of pressure reduction (five in all) one at the interface of rights 26 a, b, c, d and e with 27 a, b, c, d, and e along wall 19 and one at the discharge orifice of rings 27 a-e. The programming disc or ring 15 includes two additional axial spacing steps 15c and 15d. The fluid flow passages in each of Figures 3, 3A and 3B are indicated by broken shading lines. The flow from the high pressure side into the annular fluid flow channel 20 is through the constriction formed at the passage 14 in sleeve 13. This constriction has been reduced by the action of the programming step 15a of the programming disc 15. At this point the fluid flow through each of the forty passages 14 divides equally (Figure 3a and b) to flow in opposite directions in the annular channels 20 of the staging rings, with the channel serving as recovery or expansion chambers. The sleeve 13 divides the flowstream into 40 parts through passage 14, followed by recombination in annular fluid flow channel 20. It will be seen that the staging rings 16a-e are rotated circumferentially to bring their fluid passage slots 23 to a point midway between the passages 14 of the sleeve, thus establishing the equal division of the flow.and at the same time an impingement and 90° change in flow direction. The slots 23 of the rings 16a-e at the interface with the annular channel 20 of rings 17a-e forms the second constriction or pressure dropping stage. At the entrance to this stage fluids flowing from opposite directions merge and recombine, with attendant energy losses, before the ensuing constricted flow in stage two. The next inner nested staging rings 17a-e are displaced circumferentially in the opposite direction to space their slots 23 midway between the slots of the rings 16a-e (and therefore, in radial alignment with the passages 14 in the sleeve 13). In this fashion the process of energy dissipation carries In in cascading fashions until the flow reaches the inner cylindrical discharge opening 17 defined by the inside diameter of the innermost rings 27a-e. In this space diametrically opposed streams will impinge on each other and flow direction will change by 90°, providing further dissipation of energy. The diameter of the discharge opening should be large enough to limit exit flow velocities from the system. Figure 3A illustrates a particular feature of the invention in which further energy is dissipated by five successive changes in the direction of the fluid flow vertically or along the Z axis of the systems, i.e. in the X-Z plane, thus adding to the effects of the direction changes in the Z-Y plane as shown in Figure 3B. The invention also provides when used with pilot operated valve designs, for fluid isolation of the entire energy dissipating assembly including the sleeve 13, the nested rings 15 and the pilot valve 31 (Fig. 1). This is achieved by providing a lost motion coupling space 32 between the pin 33 which is carried by the solenoid armature shaft 34 of the pilot valve 31 and the upper body 35 of the main valve disc 10. When the valve is closed, as shown in Fig. 1, the pin 33 will float in the space 32 in the disc body so that leakage fluid will surround every surface of the movable disc including the outer cylindrical surfaces indicated by the numerals 36a, 36b and 36c, the end surfaces 36d and 36e, the inner cylindrical bore 36f containing the pilot valve and its armature shaft 34 and the opening between the pilot valve 31 and its seat 31a. Pressure dropping stages in the form of cylindrical chambers 31b are provided on the lower end of the pilot valve to dissipate in stages the high energy of the fluid flow through the pilot valve when it is opened. Thus there is no metal-to-metal contact between the outer housing and the disc in which the energy is dissipated. The system will, therefore, operate more quietly than other prior art systems such for example as that shown in U.S. Patent No. 4,249,574. The invention has been illustrated and described in a range of variation and embodiments suggesting the wide range of pressure profiles which can be achieved by the programming ring, and at the same time achieving axial fluid flow direction changes as the fluid also moves radially and circumferentially in additional tortuous flow paths. Also shown is the ability to eliminate possibly unnecessary stages in the lower tiers of a given system. It should also be understood that while the invention has been shown in embodiments in which the high to low pressure flow is radially inward, i.e. the staging rings are nested inward from the sleeve 13, the staging rings can be assembled in outward nesting configurations, thus reversing the radial direction but otherwise not changing the principles and features of the invention. In such arrangement, the staging rings 16 (Figs. 4 and 5) will have the chamber 20 formed in the lower inside corner to provide a radially inward facing expansion chamber to received the outward flow of expanding fluid. Also, while the ring 16 has been illustrated in one preferred geometry which has certain advantages in efficient machinery as well as assembly, it can take other configurations. For example, it can be formed with a central circumferential channel with upper and lower horizontal flanges joined by a vertical web (on the radially inner edge for nesting inside the sleeve 13 or on the outer edge for outside nesting). Also, the circumferential array of apertures can take the form of drilled holes or other shapes which might, however, be more costly to fabricate. The invention should not, therefore, be regarded as limited except as defined in the following claims.

Claims: A multi-stage programmable pressure reducing apparatus for high energy fluids consisting of a plurality of close-fitting concentric cylindrical first and second sleeves (13, 16, 17), each of the sleeves being provided with a plurality of radial fluid passages (14; 23), spaced across the cylindrical surfaces of the sleeves (13, 16, 17) in a desired pattern, the sleeves (13, 16, 17) being rotated, one relative to the other in such a way that the radial fluid passages (14; 23) provide a plurality of labyrinthine fluid flow paths from the outside to the inside of the sleeves (13, 16, 17), characterized in that the first sleeve is a cylindrical support sleeve (13) having a plurality of axially spaced apart tiers of said circumferentially spaced apart radial fluid passages (14), the second sleeves consist of a plurality of pressure dropping, staging rings (16, 17) adapted to be carried concentrically by the first sleeve (13) stacked in tiers of nested, staging rings (16, 17) of progressively differing diameters to establish a plurality of pressure dropping stages, each ring (16, 17) having annular walls (21, 22) extending radially and axially to define at least a portion of an annular fluid flow channel (20), the axially extending wall (21) of each ring (16, 17) having a plurality of said circumferentially spaced apart radial fluid passages (23) communicating with its annular fluid flow channel (20), said staging rings (16) proximate to the first sleeve (13) being axially adjustable to bring their respective annular fluid flow channels (20) into variably adjustable register with one corresponding array of said circumferentially spaced apart radial passages (14) in the first sleeve (13), the nested rings (16, 17) being relatively axially adjustable to bring their respective annular channels (20) into variably adjustable register to establish pressure dropping stages of selectable size, and programming spacer means, comprising a programming disc (15, 25) arranged above the first tier (16a, 17a) of staging rings (16, 17) and/or between tiers (16c-17c; 16d) of below the first tier (16a-17a), said programming disc (15, 25) adjusting the degree of axial registration of the respective annular flow paths of the staging rings (16, 17) in subsequent tiers with the proximate radial fluid flow passages and having a configuration which enables a different degree of axial registration for each pressure dropping stage, and means (24) to secure the staging rings (16, 17) in fixed operating relationship, whereby the fluid flow from the high pressure side to the low pressure side will cause the flow to split and contract at the radial passages (23) , to recombine in the annular flow paths (20) with associated impingement and frictional losses and to change directions both circumferentially and axially, and whereby the pressure profiles at all stages of pressure reduction can be programmed by said spacer means (15, 25). Apparatus as set forth in claim 1 said pressure reducing apparatus being part of a valve disc (10) adapted to be movably mounted within a valve body having a fixed valve seat (12) into which the said first sleeve (13) passes to allow the valve disc (10) to seal against the seat (12), characterized in that said first sleeve (13), as the valve is progressively opened, presents the tiers (16a-e) of the circumferentially spaced fluid passages (23) successively to the fluid flow. Apparatus as set forth in claim 1, characterized in that there are different numbers of tiers (16a-16e; 17a-17c) in the respective pressures dropping stages. Apparatus as set forth in claim 1, characterized in that the means to secure the staging rings (16, 17) in fixed operating relationship include disc means (24) to secure the staging rings (16, 17) in the first sleeve (13) at the last tier (16d-16e) of each stage. Apparatus as set forth in claim 4, characterized in that said disc means (24) seal the annular flow path (20) in the ring (16e) which is in the last tier (16d-16e) of each stage. Apparatus as set forth in claim 1, characterized in that each staging ring (16, 17) comprises a substantially rectangular unitary member having substantially one corner position removed to define the annular fluid flow channel (20). Apparatus as set forth in claim 6, characterized in that said staging ring (16, 17) is substantially square, with the thickness, measured axially, of the wall (21) defining the radial portion of the channel (20) corresponding approximately to the axial dimensions of the radial flow passages (14) in the first sleeve (13) and in the other rings (16, 17). Apparatus as set forth in claim 7, characterized in that the radial fluid passages (23) in the respective axially extending walls (21) of the staging rings (16, 17) being equidistant and of equal size. Apparatus as set forth in claim 8, characterized in that the radial fluid passages (23) in the staging rings (16, 17) being rectangular. Apparatus as set forth in claim 9, characterized in that the circumferential spacing of the radial flow passages (23) of the successive stages (16, 17) of pressure drop being circumferentially spaced to cause the flow through each to divide substantially equally.

Inventors: BEAUMAN RONALD, TRIPP DALE S, BEAUMAN, RONALD, TRIPP, DALE S.
Applicants: TARGET ROCK CORP, TARGET ROCK CORPORATION
Application year: 1990
Main classification: F16K47
IPC codes: F15D1, F16L55, F16K47