US20180003011A1

US20180003011A1 - Louvered Pipe Shroud Assembly

Info

Publication number: US20180003011A1
Application number: US15/627,708
Authority: US
Inventors: Donald H. Michel; Steven Mark Everritt
Original assignee: Delta Screw and Filtration LLC
Current assignee: Delta Screw and Filtration LLC
Priority date: 2016-06-30
Filing date: 2017-06-20
Publication date: 2018-01-04

Abstract

Embodiments of an apparatus of the present invention generally include a filtration assembly having a louvered shroud circumferentially positioned around a perforated inner pipe, such that at least a substantial portion of the shroud's inner surface contacts and frictionally engages the outer surface of the inner pipe. Embodiments of a method of the present invention generally include spirally wrapping a substantially flat strip of louvered material around the inner pipe, wherein adjoining edges of the louvered material abut and are at least partially welded together, to provide the shrouded pipe. Other method embodiments generally include an inner pipe having a louvered shroud positioned there around being introduced to a device operable to, dynamically or statically, radially compress the shroud such that at least a substantial portion of the shroud's inner surface contacts and frictionally engages at least a substantial portion of the outer surface of the inner pipe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Applications No. 62/356,935, filed on Jun. 30, 2016, which application is incorporated herein by reference as if reproduced in full below.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus and methods for filtering fluid in a well bore. More specifically, the present invention addresses an apparatus which provides a louvered filtration surface and methods of manufacturing same.

BACKGROUND

In subsurface oil and gas drilling operations, filters are typically employed to prevent particulate matter from being entrained in the fluid product piped to the surface. To effectively screen fine particles, a woven filter medium may be utilized. Due to the strength concerns regarding woven filter media, perforated shrouds are utilized to protect the filter medium. See, e.g., U.S. Pat. No. 6,382,318 to Whitlock.
In one known process, an outer perforated jacket is assembled over a filter medium, which is itself placed over a coarse support screen or drainage layer by transversally wrapping a sheet of filter medium there around, and this combination is advanced through a die such that inward protrusions of the jacket are mechanically compressed against the filter media to effect a seal of the subassembly. This subassembly can then be placed on a perforated support pipe or may be formed on the perforated support pipe. See, e.g., U.S. Pat. No. 6,305,468 to Broome, et al.
In another process, a filter medium is cold-rolled with a perforated metal shroud material and spiral-wound, around an inner support or without an inner support, to form a filter cartridge. In such application, adjoining longitudinal edges of spirally-wound filter medium overlap and adjoining longitudinal edges of spirally-wound shroud material are welded together. The filter cartridge can then be slid onto a base pipe. See U.S. Pat. No. 7,287,684 to Blackburne, Jr.
In yet another process, two offset filter medium layers are spirally wrapped around a spirally wire-wrapped drain filter, and a spirally wire-wrapped cover filter is provided over the filter medium layers. See U.S. Patent Application Publication No. 2015/0238884 to Vu.
By another known technology, sub-surface filtration is accomplished by use of a slotted pipe (“slotted liner”) which has longitudinally cut slots along the length of the piping sections. See, e.g., U.S. Pat. No. 1,135,809 to Jones. Typically, the slotted liner is provided by machining multiple longitudinal slots throughout the length and circumference of each pipe section. Limitations of using slotted liners include, however, poor slot dimension precision, pluggage issues, high pressure drop, and a maximum flow area of only 2-3% of the pipe surface.
While these filtration systems may be useful, it would be advantageous to provide a filtration apparatus having only a single outer component and capable of providing acceptable filtration performance.

BRIEF SUMMARY OF THE INVENTION

Embodiments of an apparatus of the present invention generally comprise a filtration assembly comprising a louvered shroud circumferentially positioned around a perforated inner pipe, such that at least a substantial portion of an inner surface of the shroud contacts and frictionally engages the outer surface of the inner pipe. One embodiment of a method of the present invention generally comprises spirally wrapping a flat strip of louvered material around the inner pipe, wherein adjoining edges of the louvered material are welded together. Another embodiment of a method of the present invention generally comprises providing an inner pipe and a louvered shroud positioned there around to a device operable to dynamically radially compress the shroud such that at least a substantial portion of an inner surface of the shroud contacts and frictionally engages the outer surface of the inner pipe. Still another embodiment of a method of the present invention generally comprises providing an inner pipe and a louvered shroud positioned there around to a device operable to statically compress the shroud such that at least a substantial portion of an inner surface of the shroud contacts and frictionally engages the outer surface of the inner pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the exemplary embodiments, reference is now made to the following Description of Exemplary Embodiments of the Invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 depicts an embodiment of a shroud section of the present invention.

FIG. 2 depicts an embodiment of formation of a shroud section.

FIG. 2A depicts an alternative embodiment of formation of a shroud section.

FIG. 3 depicts an embodiment of a shroud section disposed on a pipe section.

FIG. 4 depicts an embodiment of formation of a shroud section on a pipe section.

FIG. 5 depicts an embodiment of a shrouded pipe section being circumferentially reduced using a tube reduction mill.

FIG. 6 shows another view of the tube reduction mill of FIG. 5.

FIG. 7 depicts an end view of an embodiment of a shrouded pipe section.

FIG. 8 depicts an embodiment of a shrouded pipe section being circumferentially reduced using a static die.

FIG. 8A shows another view of the static die of FIG. 8.

FIG. 9 shows another view of an embodiment of a shrouded pipe section being circumferentially reduced using a static die.

FIG. 10 depicts an embodiment of a shroud section louver.

FIG. 10A shows another view of the shroud section louver of FIG. 10.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The exemplary embodiments are best understood by referring to the drawings with like numerals being used for like and corresponding parts of the various drawings. Use of relative terms herein, such as “top,” “bottom,” “upper,” “lower,” “right,” “left,” and the like, are used for illustrative purposes only are not intended to limit the invention to a disclosed orientation or arrangement.
In various embodiments of the present invention, a louvered shroud section is provided circumferentially around a pipe section. In an embodiment depicted in FIG. 1, a louvered shroud section 2 comprises a substantially tubular component comprising an exterior surface 4. In one embodiment, exterior surface 4 comprises a plurality of louvers 6 comprising indentations 8. In one embodiment, a louver 6 comprises an indentation 8 comprising a portion of the exterior surface 4 angled inwardly toward an interior 10 of tubular shroud section 2. In one embodiment, a louver 6 comprises one or more apertures 12 within the indentation 8 (see FIGS. 10 and 10A). Apertures 12 allow for fluid flow between the exterior of shroud section 2 and an interior 10 of shroud section 2.
In one embodiment, shown in FIG. 2, shroud section 2 is produced by spirally cold-rolling lengths of a substantially planar material 22 containing a plurality of louvers 6 around a forming mandrel 13 to form a tubular shroud section 2. In one embodiment, shown in FIG. 2A, shroud section 2 is produced by spirally cold-rolling lengths of a substantially planar material 22 containing a plurality of louvers 6 without use of a forming mandrel 13 to form a tubular shroud section 2. In the embodiments of FIGS. 2 and 2A, material 22 is provided in coiled form, although other arrangements may be employed. Although the embodiments of FIGS. 2 and 2A depict spirally wrapping material 22, the invention is not so limited and other orientations of material 22 may be employed, such as but not limited to, axially wrapping one or more sheets of material 22 around pipe 14 or a forming mandrel 13. In one embodiment, the material comprises steel, although other materials may be employed, as would be understood by one skilled in the art. In one embodiment, the material comprises stainless steel.
In one embodiment, louvers 6 are pre-formed in the material by providing indentations 8 through “punching” a surface of a section of material 22, although other methods of forming indentations 8 may be utilized, as would be understood by one skilled in the art. In one embodiment, shown in detail in FIGS. 10 and 10A, a punched indentation 8 comprises substantially parallel “top” edge 9 a and “bottom” edge 9 b, wherein a depressed section 11 remains connected thereto there between. In one embodiment, substantially parallel “left” edge 15 a and “right” edge 15 b border a created aperture 12. In other embodiments (not shown), louvers 6 and/or indentations 8 may comprise different physical features.
The number, orientation, and positioning of indentations 8 may be varied as required for a particular application. In the embodiment depicted in FIG. 2, the indentations 8 protrude inward in the coiled material 22; i.e., upward away from surface 26, such that upon formation of shroud section 2 the indentations 8 extend inwardly toward interior 10 of shroud section 2. This provides the louvered apertures 12 in shroud section 2.
In one embodiment, coiled material 22 is provided to a spiral tube welding machine (not shown) equipped with a forming mandrel 13 sized for a desired shroud section diameter. In one embodiment, material 22 is provided to the spiral tube welding machine by means of power pinch rollers 23 configured to correspond to the desired radius of shroud section 2. In one embodiment, the material 22 is spirally wrapped such that adjacent edges 24 abut each other. In one embodiment, material 22 is provided through one or more guides 25 to assist in providing material at the desired angle. In one embodiment, at least a portion of abutting edges 24 of the wrapped material are affixed to each other, such as by welding. In one embodiment, when sufficient material 22 has been wrapped around mandrel 13 to produce a shroud section 2 of desired length, the mandrel 13 is removed and the ends 58 of shroud section 2 are trimmed to provide a uniform length thereof. Similarly, in an embodiment where a mandrel is not employed, when sufficient material 22 has been pre-formed through the pinch rollers 23 to form the desired diameter to produce a shroud section 2 of desired length, the ends 58 of shroud section 2 are trimmed to provide a uniform length thereof.
While the indentations 8 in FIG. 2 are depicted as substantially rectangular and oriented lengthwise parallel to the longitudinal axis of shroud section 2, such depiction is only exemplary and other shapes and/or orientations are contemplated. In addition, the pattern or patterns of indentations 8 in exterior surface 4 of shroud section 2 may be regular or irregular.
Referring to FIG. 3, a shrouded pipe section 30 comprises a shroud section 2 disposed circumferentially around a pipe section 14. In one embodiment, pipe section 14 may comprise any substantially tubular structure containing one or more orifices 16 in the exterior surface 18 thereof (see FIG. 4). In one embodiment, pipe section 14 comprises perforated pipe. As described in more detail below, shroud section 2 may be provided on pipe section 14 by different means.
In one aspect, apertures 12 act to filter fluid flowing between the exterior of shroud section 2 and the interior 10 thereof. Thus, the dimensions of apertures 12 at least partially determine the effective filtration capability of shroud section 2.
In one embodiment, fluid communication between the interior 10 of shroud section 2 and an interior 20 of pipe section 14 is achieved via the one or more orifices 16 disposed in the exterior surface 18 of pipe section 14. In one embodiment, a substantial portion of interior surfaces 28 of depressed sections 11 of shroud section 2 (see FIGS. 10 and 10A) are frictionally engaged with a substantial portion of the exterior surface 18 of pipe section 14, i.e., shroud section 2 is in an interference fit therewith.
In one embodiment, shown in FIG. 4, shroud section 2 is provided on pipe section 14 by direct spiral wrapping of material 22 onto pipe section 14. Similar to as described above with respect to FIG. 2, in one embodiment direct wrapping of pipe 14 comprises spirally cold-rolling lengths of a material 22, containing a plurality of louvers 6, directly around pipe section 14 to form a tubular shroud section 2 there around. In one embodiment, at least a portion of abutting edges 24 of material 22 are affixed to each other, such as by welding. Such affixation may be performed during the direct wrapping process. In one embodiment, any excess material 22 at one or both ends 58 of shroud section 2 may be trimmed to provide a uniform length shroud section 2. In one embodiment, providing shroud section 2 on pipe section 14 by directly wrapping produces an interference fit between the interior surfaces 28 or depressed sections 11 of shroud section 2 and the exterior surface 18 of pipe section 14. In one embodiment, after shroud section 2 is provided around pipe section 14 in an interference fit, shroud section 2, proximate either or both ends thereof, may be affixed to pipe section 14. In one embodiment, such affixation comprises welding to the exterior surface 18 of pipe section 14. In another embodiment, an interference fit end ring 59 may be provided on circumferentially to one or both ends 58 of shroud section 2 and welded to the exterior surface 18 of pipe section 14.
In one embodiment, a pre-formed shroud section 2 is slid longitudinally over a pipe section 14 to form a slid-over shrouded pipe section 30. In one embodiment, pipe section 14 comprises pin (male) connectors at either end thereof, while in other embodiments, one or both ends of pipe section 14 may comprise a coupling (female) component, which may be provided on pipe section 14 or may be integral therewith. For simplicity of description only, reference to the ends of pipe section 14 will be to a pin end 32 and a coupling end 34. In one embodiment, the sliding of shroud section 2 over pipe section 14 comprises sliding the shroud section 2 from the pin end 32 of the pipe section 14 toward the coupling end 34 of the pipe section. The shroud section 2 is then positioned a predetermined distance from the coupling end 34 and the pin end 32 of the pipe section 2.
Provision of shroud section 2 onto pipe section 14 by such sliding means may result in gaps 76 between the interior surfaces 28 of depressed sections 11 and the exterior surface 18 of pipe section 14. In one aspect, even if such gaps 76 are not created, the sliding of shroud section 2 onto pipe section 14 may not effectuate an interference fit there between. In various embodiments of the present invention, a desired interference fit between shroud section 2 and pipe section 14 may be accomplished by radial compression of a slid-over shrouded pipe section 30, thereby providing circumferential reduction of shroud section 2.
In one embodiment, the shroud section 2 of a slid-over shrouded pipe section 30 is affixed to the exterior surface 18 of pipe section 14 on the leading end of pipe section 14 that is to be provided for circumferential reduction. In one embodiment, the pin end 32 is utilized as the leading end. In one embodiment, such affixation comprises tack welding shroud section 2 to the exterior surface 18 of pipe section. The slid-over shrouded pipe section 30 may then be provided to a device operable to dynamically or statically compress the shroud section 2 such that a substantial portion of inner surface 28 of depressed sections 11 of the shroud section 2 contacts and frictionally engages the exterior surface 18 of the pipe section 14, i.e., produces an interference fit there between.
Now referring to FIG. 5, in one embodiment, the slid-over shrouded pipe section 30 is advanced, one or more times, through one or more tube-reduction mills 38 to dynamically achieve an interference fit of shroud section 2 around pipe section 14. Tube reducing mills are generally known in the art. See, for example, U.S. Pat. No. 8,166,789 to Okui, et al., U.S. Pat. No. 5,533,370 to Kuroda, et al., and U.S. Pat. No. 4,260,096 to Samarynov, et al., each of which is incorporated by reference herein in its entirety. Suitable tube reduction mills are available from Addison Machine Engineering, Inc. of Reedsburg, Wis.
In one embodiment, tube reduction mill 38 comprises a plurality of substantially circular shaped rollers 40, each comprising a concave exterior groove 42. In the embodiment shown in FIG. 5, reduction mill 38 comprises four rollers 40 positioned at 90° angles to each other, although other orientations may be employed. In other embodiments (not shown), reduction mill 38 may comprise more or fewer rollers 40, which may be symmetrically or unsymmetrically oriented. In the embodiment of FIG. 5, the rollers 40 are disposed such that a centralized, substantially circular mill opening 44 (shown in detail in FIG. 6) is created by grooves 42 via positioning of the rollers 40. The individual rollers 40 are adjusted to form the desired mill opening 44 diameter 46. As would be understood by one skilled in the art, a tube reduction mill 38 may comprise various mechanisms (not shown) for controlling the dimensions of mill opening 46 and advancing a slid-over shrouded pipe section 30 there through. In other embodiments (not shown), separate means for advancing a slid-over shrouded pipe section 30 through a tube reduction mill 38 may be employed.
In one embodiment, opposing rollers 40 a, 40 c, and/or 40 b, 40 d (shown in FIG. 6), of tube reduction mill 38 may be adjusted in tandem through control of tube reduction mill 38. In one embodiment, control of rollers 40 may include utilization of a mechanism comprising one or more micrometers. In one embodiment, control of tube reduction mill 38 comprises use of a pressure measurement device, such as, but not limited to, a load cell, to determine pressure between the exterior surface 4 of shroud section 2 and one or more rollers 40.
Before introduction of slid-over shrouded pipe section 30 to tube reduction mill 38, that component comprises an initial shroud section 2 outer diameter 48, as shown in FIG. 7, which includes the outer diameter 50 of pipe section 14, twice the thickness 52 of shroud section 2, as well as any gaps 76 between the interior surface 28 of depressed sections 11 of shroud section 2 and the exterior surface 18 of pipe section 14. In one aspect, the diameter 46 of mill opening 44 determines a reduced outer shroud diameter 54 which the circumferentially reduced shrouded pipe section 30 comprises upon exiting tube reduction mill 38.
Reference to the diameter 46 of mill opening 44 as determinative of the reduced outer shroud diameter 54 of circumferentially reduced shrouded pipe section 30 presumes that the mill opening 44 employed is substantially round; however, other geometries of slid-over shrouded pipe section 30 are suitable for the such circumferential reduction using tube reduction mill 38, in which case the cross-sectional area of tube reduction mill 38 opening 44, whatever shape that might comprise, will determine the outer dimensions of the circumferentially reduced shrouded pipe section 30. Accordingly, in one embodiment, grooves 42 of rollers 40 may have differing depths and/or geometries.
In one embodiment, as shown in FIG. 5, slid-over shrouded pipe section 30 is introduced to, and advanced through, tube reduction mill 38, thereby reducing initial shroud outer diameter 48 to a reduced outer shroud diameter 54. In one aspect, this provides an interference fit of shroud section 2 around pipe section 14. If the desired fit is not achieved, the configuration of tube reduction mill 38 opening 44 can be adjusted, whereupon the slid-over shrouded pipe section 30 is re-introduced to, and advanced through, tube reduction mill 38 to achieve the desired fit.
In one aspect, radial compression of slid-over shrouded pipe section 30 achieved by the operation of tube reduction mill 28 may comprise sufficient compressive force to deform louvers 6, and thereby change the dimensions of apertures 12. In one embodiment, all or substantially all gaps 76 are eliminated through effected contact between the interior surfaces 28 of depressed sections 11 of shroud section 2 and the exterior surface 18 of pipe section 14. In any embodiment where shroud section 30 has been elongated by operation of tube reduction mill 38, excess length of circumferentially reduced shroud section 2 may be trimmed. In one embodiment, such trimming provides a desired non-shrouded length 56 between end 58 of shroud section 2 and end 60 of coupling end 34 end of pipe section 14. In one embodiment, both ends of the shroud section 2 are then welded to the exterior surface 18 of pipe section 14.
Referring now to FIG. 8, in one embodiment, the slid-over shrouded pipe section 30 is advanced, one or more times, through one or more static dies 62 to statically provide the circumferential reduction required to achieve an interference fit of shroud section 2 around pipe section 14. Examples of static dies are disclosed in the abovementioned U.S. Pat. No. 6,305,468 Broome, et al., and in U.S. Pat. No. 5,611,399 to Richard, et al., each of which is incorporated by reference herein in its entirety.
In one embodiment, a substantially annular static die 62 comprises a substantially round die opening 64 comprising a fixed exit diameter 66 (see also FIGS. 8A and 9). In one embodiment, static die 62 is affixed to a support structure (not shown) to stabilize the static die 62. In one embodiment, a means (not shown) of advancing slid-over shrouded pipe section 30 through static die 62 is provided. In one embodiment, shown in detail in FIG. 8A, the structure of static die 62 is configured such that an entry diameter 67 is greater than an exit diameter 66. As described above with regard to utilization of tube reduction mill 38, slid-over shrouded pipe section 30 comprises an initial shroud section 2 outer diameter 48, as shown in FIG. 7, that includes the outer diameter 50 of pipe section 14, twice the thickness 52 of shroud section 2, as well as any gaps 76 between the interior surfaces 28 of depressed sections 11 of shroud section 2 and the exterior surface 18 of pipe section 14. In one aspect, the exit diameter 66 of static die opening 62 determines the reduced outer shroud diameter 54 which the circumferentially reduced shrouded pipe section 30 comprises upon exiting tube static die 62.
Reference to the exit diameter 66 of static die opening 62 as determinative of the reduced outer shroud diameter 54 of circumferentially reduced shrouded pipe section 30 presumes that the static die 62 opening 64 employed is substantially round; however, other geometries of slid-over shrouded pipe section 30 are suitable for the such circumferential reduction using static die 62, in which case the cross-sectional area of static die 62 opening 64, whatever shape that might comprise, will determine the outer dimensions of the circumferentially reduced shrouded pipe section 30.
In one embodiment, a slid-over shrouded pipe section 30 is produced as described above. In one embodiment, as shown in FIGS. 8 and 9, slid-over shrouded pipe section 30 is introduced to, and advanced through, static die 62, thereby reducing initial shroud outer diameter 48 to a reduced outer shroud diameter 54. In one aspect, this provides an interference fit of shroud section 2 around pipe section 14. If the desired fit is not achieved, the exit diameter 66 of static die 62 opening 64 may be reduced, whereupon the slid-over shrouded pipe section 30 is re-introduced to, and advanced through, static die 62 to achieve the desired fit.
In one aspect, radial compression of slid-over shrouded pipe section 30 achieved by the operation of static die 62 may comprise sufficient compressive force to deform louvers 6, and thereby change the dimensions of apertures 12. In one embodiment, all or substantially all gaps 76 are eliminated through effected contact between the interior surfaces 28 of depressed sections 11 of shroud section 2 and the exterior surface 18 of pipe section 14.
As described above, in any embodiment where shroud section 30 has been elongated by operation of static die 62, excess length of circumferentially reduced shroud section 2 may be trimmed. In one embodiment, such trimming provides a desired non-shrouded length 56 between end 58 of shroud section 2 and end 60 of coupling end 34 of pipe section 14. In one embodiment, both ends of the shroud section 2 are then welded to the exterior surface 18 of pipe section 14.
Although the circumferential reduction methods outlined above have been described as mutually exclusive of each other, the invention is not so limited and such methods may be combined; i.e., a slid-over shrouded pipe section 30 may be circumferentially reduced using a tube reduction mill, and then the once circumferentially reduced shrouded pipe section 30 may be further circumferentially reduced using a static die, and vice versa. In addition, multiple utilizations of one or both methods may be combined.
As one objective in producing a shrouded pipe section 30, wherein the pipe shroud section 2 is disposed in an interference fit with a pipe section 14, is to provide a filtration mechanism around at least a portion of pipe section 14, the dimensions of aperture 12 are important in defining the filtration capabilities of the shrouded pipe section 30. Accordingly, it may be desired to carefully control the accuracy and precision of forming apertures 12 and/or the precision of altering apertures 12 during a radial circumferential compression.
Referring to FIGS. 10 and 10, in one embodiment, a determination of aperture 12 size is accomplished by measuring a louver 6 depth 70. In one embodiment, louver 6 depth 70 is measured using a thread depth micrometer. Other methods of measuring louver depth may be employed, including but not limited to, measurement using a laser or other light or electromagnetic wave system. In one aspect, the louver 6 depth 70 minus the thickness 52 of shroud section 2 equals the aperture 12 depth 74. In one embodiment, a precision in indentation 8 formation, and/or alteration during a radial circumferential compression operation, allows for control of filtration capabilities of shrouded pipe section 30 without requiring more detailed measurement of the cross-sectional area of aperture 12; that is, consistency in aperture depth 74, along the right edge 15 a and left edge 15 b of louver 6 permits measurement of aperture depth 74 be limited to one measurement thereof along an aperture 12. In one embodiment, such measurement is performed at a point substantially equidistant from top edge 9 a and bottom edge 9 b.
Operational control of the methods of producing a finished shrouded pipe section 30 is desired to insure provision of a filtration mechanism of prescribed capabilities. When the shrouded pipe section 30 is provided utilizing the direct wrapping method, measurements and calculations, including slot depth calculations, are performed to determine whether the finished shrouded pipe section 30 possesses desired characteristics. If undesired aperture 12 dimensions are obtained, changes to the process may be undertaken as corrective action to provide a desired aperture depth 74. In addition, a shrouded pipe section 30 provided utilizing the direct wrapping method may be introduced to a radial compression mechanism to affect necessary changes in desired characteristics.
When the interference fit shrouded pipe section 30 is provided utilizing a radial compression method, measurements and calculations, including slot depth calculations, may be performed on the pre-formed shroud section 2 and/or the slid-over shrouded pipe section 30 and/or the circumferentially reduced shrouded pipe section 30 to determine whether that component possesses the desired louver characteristics for a particular stage of the process. Because radial compression of slid-over shrouded pipe section 30 achieved by the operation of a tube reduction mill 38 and/or a static die 62 may comprise sufficient compressive force to deform louvers 6, and thereby alter the dimensions of apertures 12, control of the radial compression process is desirable.
When a tube reduction mill 38 is being employed to produce a shrouded pipe section 30, control of operational parameters includes, but is not limited to, adjustment of one or more rollers 40 to effect a change in the dimensions of mill opening 44. In one embodiment, such adjustments may be performed during the radial compression process. In one embodiment, such control may comprise use of a pressure measurement device, such as, but not limited to, a load cell, to determine pressure between the exterior surface 4 of shroud section 2 and one or more rollers 40. Accordingly, such pressure measurements may be utilized to adjust the dimensions of mill opening 44 to provide desired aperture 12 depth 74. In one embodiment, predictive calculations and/or historical data may be employed to program a desired pressure scheme such that obtained pressure measurements can be compared to programmed parameters and deviations therefrom can us used, directly or indirectly, automatically or manually, to adjust tube reduction mill 38 control parameters, including but limited to, the dimensions of mill opening 44.
In one embodiment, a method of the present invention comprises providing a louvered material and directly spirally wrapping the material around a perforated pipe section, such that an interference fit between a portion of the material and the exterior of the pipe is achieved, thereby producing a louvered shrouded pipe section.
In one embodiment, a method of the present invention comprises providing a louvered shroud section, sliding the shroud section over a pipe section to form a slid-over shrouded pipe section, and radially compressing, statically or dynamically, the slid-over shrouded pipe section to produce a louvered shrouded pipe section having an interference fit between a portion of the interior surface of the shroud section and the exterior of the pipe.
While the preferred embodiments of the invention have been described and illustrated, modifications thereof can be made by one skilled in the art without departing from the teachings of the invention. Descriptions of embodiments are exemplary and not limiting. Disclosure of existing patents, publications, and known art are incorporated herein by reference to the extent required to provide details and understanding of the disclosure herein set forth.

Claims

We claim:

1. A louvered shrouded pipe section, comprising:

a substantially tubular shroud comprising an exterior surface comprising a plurality of louvered apertures disposed thereon, wherein said apertures allow fluid communication between the exterior of said shroud and the interior of said shroud; and

a substantially tubular pipe section comprising an exterior surface comprising a plurality of orifices disposed thereon, wherein said orifices allow fluid communication between the exterior of said pipe section and the interior of said pipe section;

wherein:

said shroud circumferentially encompasses at least a portion of said pipe section;

at least a portion of an inner surface of said shroud contacts and frictionally engages said exterior surface of said pipe section; and

fluid communication is provided between said exterior of said shroud and an interior of said pipe, via said apertures and said orifices.

2. The louvered shrouded pipe section of claim 1, wherein one or more of said louvered apertures comprise an indentation comprising a portion of said exterior surface of said louvered shroud angled inwardly toward said interior of said shroud.

3. The louvered shrouded pipe section of claim 1, wherein said tubular shroud is affixed to said exterior surface of said pipe section proximate either or both ends of said tubular shroud.

4. The louvered shrouded pipe section of claim 1, wherein one or more of said louvered apertures is formed in said shroud by punching said exterior surface of said louvered shroud.

5. The louvered shrouded pipe section of claim 4, wherein at least one said aperture formed by punching comprises an indentation comprising a first edge and a second edge parallel to each other, and a depressed section connected between said first edge and a second edge.

6. The louvered shrouded pipe section of claim 5, wherein said depressed section, between a location of connection with said first edge and a location of connection with said second edge, is substantially planar.

7. A method of producing a louvered shrouded pipe section, comprising:

providing a substantially planar material comprising a surface comprising a plurality of louvered apertures; and

spirally wrapping said material around a substantially tubular pipe section, wherein said pipe section comprises an exterior surface comprising a plurality of orifices disposed thereon, thereby forming a louvered shroud circumferentially around said pipe section;

wherein:

fluid communication is provided between the exterior of said shroud and an interior of said pipe, via said apertures and said orifices.

8. The method of claim 7, wherein said spirally wrapping said material around a substantially tubular pipe section comprises cold rolling said material.

9. The method of claim 7, wherein one or more of said louvered apertures comprise an indentation comprising a portion of said exterior surface of said louvered shroud angled inwardly toward said interior of said shroud.

10. The method of claim 7, further comprising affixing said tubular shroud to said exterior surface of said pipe section proximate either or both ends of said tubular shroud.

11. The method of claim 7, wherein one or more of said louvered apertures is formed in said shroud by punching said exterior surface of said louvered shroud.

12. The method of claim 11, wherein at least one said aperture formed by punching comprises an indentation comprising a first edge and a second edge parallel to each other, and a depressed section connected between said first edge and a second edge.

13. The method of claim 12, wherein said depressed section, between a location of connection with said first edge and a location of connection with said second edge, is substantially planar.

14. A method of producing a louvered shrouded pipe section, comprising:

providing a substantially tubular shroud comprising a plurality of louvered apertures;

advancing said shroud over a substantially tubular pipe section, wherein said pipe section comprises an exterior surface comprising a plurality of orifices disposed thereon, thereby forming a louvered shrouded pipe section; and

radially circumferentially compressing said louvered shrouded pipe section by advancing said louvered shrouded pipe section through at least one compression device;

whereby:

at least a portion of an inner surface of said shroud contacts and frictionally engages an exterior surface of said pipe section; and

15. The method of claim 14, comprising affixing said tubular shroud to said exterior surface of said pipe section proximate a lead end thereof prior to radially circumferentially compressing said louvered shrouded pipe section.

16. The method of claim 14, wherein said compression device comprises a tube-reduction mill.

17. The method of claim 16, wherein said tube-reduction mill comprises four rollers positioned at ninety degree angles to each other.

18. The method of claim 16, wherein said tube-reduction mill is controllable utilizing a pressure measurement device.

19. The method of claim 14, wherein said compression device comprises a static die.

20. The method of claim 14, wherein said radially circumferentially compressing said louvered shrouded pipe section elongates said shroud, and an excess length of said shroud is eliminated.