WO2014151695A2

WO2014151695A2 - Anti-telescoping device and handle for spiral wound membrane element

Info

Publication number: WO2014151695A2
Application number: PCT/US2014/026257
Authority: WO
Inventors: Irving Shelby; Craig R. Bartels; James E. Beck
Original assignee: Hydranautics
Priority date: 2013-03-15
Filing date: 2014-03-13
Publication date: 2014-09-25
Also published as: WO2014151695A3

Abstract

An anti-telescoping device (ATD) is provided for installing a spiral wound filtration element in a tubular pressure vessel, the ATD being a generally wagon wheel-shaped disc having an outer peripheral rim, a central hub, a plurality of annularly spaced ribs connecting the peripheral rim with the central hub, and engagement catches located at transitions of the ribs with the peripheral rim for receiving projections from a handle. The handle for holding, installing and/or extracting a spiral wound filtration element with ATD has a plurality of annularly spaced legs extending radially outward and axially from a central holding portion, the legs having engagement feet at distal ends of the legs and being adapted to lock into the engagement catches in the ATD on at least one end of the filtration element. The ATD has other novel features which facilitate the insertion of the filtration element into, the operation in, and the removal from the tubular vessel.

Description

TITLE OF THE INVENTION

[0001] Anti-Telescoping Device and Handle for Spiral Wound Membrane Element

CROSS-REFERENCE TO RELATED APPLICATION

[0002] This application claims the benefit of U.S. provisional patent application 61/787,545, filed March 15, 2013, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0003] Membrane element manufacturers have traditionally designed and fabricated anti- telescoping devices ("ATD") for installation at one or both distal ends of a spiral wound filtration element. Their function is to reduce tendency of spiral wound elements to unwind by telescoping, which is caused by a pressure differential created across the element by water flow rates. ATDs also protect element ends from damage during element handling and enable them to stand upright on a stable and firm base. These ATDs have commonly been produced via plastic injection molding or traditional machining methods, employing a variety of metal and/or plastic materials.

[0004] Conventionally, circular ATDs have an elastomeric embedded brine seal, which may simply reside in a gland or groove-like constraint around the periphery of the ATD. These brine seals may take the shape of a "U-Cup," "V-Cup," quad-ring, O-ring, split ring, etc. The functionality of these seals is simply to prevent feed solution from freely flowing through or bypassing the annular gap, which is the space between an element's exterior wall and the host vessel's interior surfaces. By historical convention, element designers have sought to direct feed flow content into spaces residing between adjacent membrane leaves.

[0005] These seals, although generally effective, were prone to display various difficulties upon element insertion into and extraction from the tubular vessel. Such trouble-some characteristics included one or more of the following:

1. Seals rolled out of their grooves and effectively jammed themselves in the vessel bore;

2. Enabled end-users to install elements only in one direction;

3. Produced a fair amount of friction against vessel side wall during movement, requiring a substantial effort to cause elements to slide within vessel confines;

4. Incompatible with feed solution chemistries;

5. Required specific orientation relative to feed solution direction;

6. Necessitated lubrication prior to use; and 7. Created a non-turbulent zone behind its installation site, which created potential zones of biological growth. [0006] Moreover, ATD diameters were purposely undersized to allow ample clearance between the host vessel's bore and to facilitate element/vessel loading. A survey taken of major vessel manufacturers revealed an inner diameter range of 7.945" to 7.968", i.e., a 0.023 inch difference.

ATD diameters were historically around 7.874" (200 mm conveniently), which has been an industry de facto standard.

[0007] Finally, typical ATDs are often bonded to their membrane element via fiberglass filament windings and have a tendency to come loose and detached from the element's distal end.

This structural impediment requires remediation and has become a nuisance among end-users.

BRIEF SUMMARY OF THE INVENTION

[0008] The above described functional inadequacies and shortcomings are overcome or alleviated by various features and aspects of the invention, which may be used individually or in combination.

[0009] According to a first aspect of the invention, the traditional brine seal groove has been removed and replaced with a small residual groove accommodating an optional O-ring placement on the brine side of vessel installed tail elements. Since this positioning is immediately adjacent to vessel endcaps, element insertion/extraction is simplistic and uneventful. To supplement this improvement, an O-ring with minimum cross-sectional thickness may be installed and ensures complete closure of the annular gap regardless of the vessel's manufacturing origin. This mechanical arrangement has proven effective to prevent any performance-affecting bypass feed water quantities.

[0010] According to a second aspect of the invention, ATD outer diameter enlargement is remarkable resulting in reducing annular gaps by 70 - 93%, depending upon the vessel's manufacturing source. This innovation greatly reduces feed solution bypassing, thereby in some cases entirely eliminating the need for a brine seal presence on all coupled elements. By producing a highly restricted annular gap over an element's 40" length, the same effect can be achieved as taught by U.S. Patents 4,301,013 of Setti and 6,413,424 of Shelby.

[0011] According to a third aspect of the invention, the ATD and membrane element constitute a unified rigid one piece assembly, so configured that each distal end has a slightly contoured slot-less edge allowing minimum vessel wall contact. This innovation allows end-users to freely transit single or conjoined elements in a bidirectional manner, as a rounded ATD crown glides through along a vessel's length. This aspect reduces time and effort required for installation, which ma)' consist of upwards of eight elements per vessel utilized in massive municipal installations in excess of one thousand vessels or more.

[0012] According to a fourth aspect of the invention, the ATD is so configured to be engaged by an ancillary handle or grasping device which temporarily grasps and engages the ATD, allowing element handlers, during element manufacturing or installation, an ergonomic holdfast for carry elements. This function has been long overlooked by those skilled in the art of reverse osmosis membrane element designing and manufacturing. Many injuries have been attributed to lack of proper ergonomic holdfasts necessary for repeatable element handling. Previously, workers at both water filtration facilities and spiral wound element manufacturing sites had to physically manipulate an 8" diameter, 40" long cylindrical element body weighing up to 35 pounds. Over the course of a normal work day workers had to physically handle hundreds of elements, and individuals would grasp these elements according to their own personal proclivity.

[0013] A handle of the invention cleverly engages six ATD undercuts positioned where the spiral spokes intersect the heavy outer exterior ATD rim. For proper handle centering, a lower extending pilot guides the handle into its proper orientation by engaging the central tube or interconnector opening. Furthermore, by slightly twisting a conveniently placed vertical handle, six spider-like protuberances engage the spiral spoke ATD undercuts. An upper, vertically positioned grip, ergonomically fashioned for ambidextrous hand grasping, completes the handle configuration.

[0014] Also, the upper handle can be so fitted with a series of extensions for grasping and retrieving elements for vessel extraction, for example where the elements are 40", 80", 120" and 160" deep into pressure vessels. Vessels may be installed parallel to the ground (0°) through to vertical with the ground (90°).

[0015] According to a fifth aspect of the invention, the ATD possesses a counterbore exhibiting a robust land attribute. At one interim phase during element fabrication, exposed core tube segments extend out of both ends of an element. These exposed segments then fit closely into the ATD counterbore receptacle and come to a physical stop against the counterbore lands. The ensuing assembly now physically captures the entire core tube length and firmly sequesters its position between the two ATDs. Resultant assembly can now withstand a sustained column load with full joint participation of the core tube, ATD and exterior encasement. Prior art devices simply had a clearance ATD hole in which core tube end segments were positioned to freely articulate movement. This aspect of the invention clearly creates a more stout and sustainable membrane element, less prone to damage caused by excessive operational differential pressures and/or mishaps during physical handling.

[0016] According to a sixth aspect of the invention, the ATD ensures that all feed solution entry pathways obtain direct access into brine-side feed spacer areas. Conventional commercialized ATDs generically display designs commonly depicted as a "wagon wheel-like" configuration. "Spokes" of the wagon wheels are solid and block off feed solution pathways. Also, spokes often have thickened walls to provide radial strength but habitually do not subscribe to good plastic design molding concepts. Since plastic injection molding is the production method of choice, many products display characteristics of distorted attributes, warpage, heat sinks, heat discoloration, and inconsistent repeatable dimensions.

[0017] In ATDs according to embodiments of the invention, spiral spokes or vanes are hollowed out to promote flow to all brine-side feed spacer areas. Furthermore, a series of notched apertures additionally opens up feed solution access. Novel hollowed-out channels and notches further enhance adherence to good molding practices, which promote increased dimensional stability, amplify accurate part flatness, decrease part weight, and eliminate distortion and heat sinks.

Moreover, plastic ATDs are molded more economically by consuming less plastic resin and acquiring shorter cooling cycles during injection molding processing.

[0018] According to a seventh aspect of the invention, prominent exterior bonding sites have been placed purposely to facilitate firm anchorage of external encasement materials, such as a FRP overlay. This is done to promote increased resistance to ATD pull-off and rotation. ATDs should resolutely maintain a fixed position. Placement of 18 equally spaced notches, when filled in with encasement material, will prevent rotational actions and firmly capture ATD positioning.

Furthermore, a series of circular grooves revolving around the ATD's minor outer diameter complements the notches, by resisting pull-off forces and therefore secures the ATD in place.

Lastly, all bonding surfaces are textured to enhance bonding surface area and promote adhesion.

[0019] According to an eighth aspect of the invention, whereas ATD thicknesses are conventionally 1 " thick or greater, our enhanced design, material selection, and core tube relationship enable the ATD of the invention to be substantially thinner, thereby increasing effective membrane filtration area.

[0020] Other advantageous features of the ATD according to the invention include molded-in chamfers, which facilitate the insertion of interconnectors and/or core tubes; a generous interior bevel on the rim of the ATD, which allows easier access of feed water flow to outer peripheral leaf areas of the spiral wound membrane; surface areas on the outer peripheral rim of the ATD to accommodate potential laser-etched bar codes and other nomenclature for identifying the filtration elements; as well as the use and accommodation of traditional vents.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021] The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0022] Fig. 1 A is a perspective view of the inside face of an ATD according to an embodiment of the invention;

[0023] Fig. IB is a perspective view of the outside face of the ATD according to Fig. 1 A; and

[0024] Fig. 1 C is a partial cross-sectional view of the outer rim of the ATD taken along section line C-C in Fig. IB.

[0025] Fig. 2 is a plan view of the outside face of the ATD according to Fig. IB;

[0026] Fig. 2A is a cross-sectional view of the ATD taken along section line A-A in Fig. 2;

[0027] Fig. 2B is a lateral view of the ATD according to Fig. 2;

[0028] Fig. 2C is an enlarged broken away section B from Fig. 2B;

[0029] Fig. 2D is an enlarged broken away section D from Fig. 2B;

[0030] Fig. 2E is an enlarged broken away section C from Fig. 2C;

[0031] Fig. 3 is a plan view of the inside face of the ATD according to Fig. 1 A;

[0032] Fig. 3 A is another perspective view of the inside face of ATD similar to Fig. 1 A;

[0033] Fig. 3B is a lateral view of the ATD of Fig. 3, similar to Fig. 2B;

[0034] Fig. 3E is an enlarged section E of the ATD from Fig. 3B;

[0035] Fig. 3F is a sectional view of the ATD taken along section line F-F in Fig. 3;

[0036] Fig. 3G is a sectional view of the ATD taken along section line G-G in Fig. 3;

[0037] Fig. 3H is a sectional view of the ATD taken along section line H-H in Fig 3;

[0038] Fig. 4 is a partial inside plan view of the ATD of Fig. 3;

[0039] Fig. 4A is an enlarged broken away section of the hub portion of the ATD from Fig. 4;

[0040] Fig. 41 is a sectional view of the hub of the ATD taken along section lines I-I in Fig. 4;

[0041] Fig. 5 is a lateral view of a handle according to an embodiment of the invention for carrying a spiral wound filtration element having an ATD according to the invention;

[0042] Fig. 5 A is a top perspective view of the handle according to Fig. 5; [0043] Fig. 6A is a perspective view showing the handle of Fig. 5 engaged with the ATD in Fig. 1 on the outside;

[0044] Fig. 6B is a perspective view from the inside showing the handle of Fig. 5 engaged with the ATD in Fig. 1 ;

[0045] Fig. 7A is a lateral view of the handle of Fig 5 engaged in the ATD of Fig 1 with a grip inserted in the hub of the handle;

[0046] Fig. 7B is a perspective outside view of the grip, handle and ATD in Fig. 7A; and

[0047] Figs. 8A-8D are respectively a lateral, inside perspective; outside perspective, and inside (bottom) view of a handle similar to that of Fig. 5, but having extensions on the legs of the handle for ATD engagement when an interconnector is present.

DETAILED DESCRIPTION OF THE INVENTION

[0048] In the drawings the same reference numerals will be used throughout for designating the same or similar elements of various views and embodiments of the invention.

[0049] The ATDs and ATD handles of the invention will be described below in connection with embodiments particularly designed for a nominal 8" inside diameter (ID) pressure vessel for containing spiral wound filtration elements. However, it will be understood that similar ATDs and handles could be adapted and used for other diameter pressure vessels, such as 4", 12", 16", 18", 24" ID, etc.

[0050] The ATDs of the invention comprise generally wagon wheel-shaped discs comprising an outer peripheral rim 14, a central hub 16, and curved or spiral-shaped ribs or vanes 18 connecting the peripheral rim 14 with the hub 16. The number of ribs is not critical, but should be sufficient to provide the desired strength and rigidity to the ATD for its intended function, but not so many as to unnecessarily block flow of the fluid to be filtered or unnecessarily increase the weight and cost of the ATD. Preferably, the ATD should have three to nine ribs or vanes, and most preferably six ribs, as shown in the embodiments of the drawings.

[0051] The ATDs according to the invention may be made of any suitable hard or rigid plastic or even metal. Injection-moldable thermoplastics, such as ABS, polypropylene, polycarbonate, or polysulfone, are particularly preferred.

[0052] The ribs 18 may be straight or curved, but are preferably curved in a spiral arrangement around the central hub 16. Large radii transitions 20 from the vanes to the central hub enhance the strength of the ATD, and the large holes or spaces 21 between the vanes reduce weight and cost of the ATD. [0053] The ribs 18 may be hollowed out on their inside (facing the spiral wound element) by axial grooves 22 along the length of the ribs, as well as by transverse notches 24, which enhance water flow into the filtration element, while reducing part weight and cooling time and part cost of the ATD. At the corners where the ribs 18 transition into the peripheral rim 14, ledges or flanges 26 may be provided as engagement catches for receiving the grasping device or extraction tool discussed below.

[0054] The central hub 16 includes a counterbore 28 with a physical stop 30. The core tube of the filtration element is inserted into the counterbore and butts against the physical stop. Therefore, the element load is jointly carried by the ATD/core tube assembly to sustain column strength.

[0055] The hub 16 may further include peripheral holes or grooves 32 to facilitate core tube repair activities and further reduce part weight and cost The inside edge of the counterbore 28 may be beveled or chamfered to avoid collision fit with excess adhesive residue and facilitate core tube insertion. As best shown in Fig. IB, the outside (brine side) of the counter bore 28 also has a lead-in chamfer 36 to accommodate and protect the O-rings of interconnectors between the filtration elements.

[0056] For a nominal 8" ID pressure vessel, the ATDs of the invention preferably have an outer peripheral diameter of approximately 7.940" (201.67cm). As shown in the cross-sectional view of Fig. 1C, the peripheral rim of the ATD has an outer surface having the following features (working from outside to inside): a rounded outer radius 38, which facilitates the element leading into the host vessel and protects against vacuum bag puncture; an O-ring groove 40 for optional insertion of an O-ring on the tail (end) element in a multiple element installation; encasement traps 42 for

FRP/epoxy matrix or polyurethane overlay or overcoat for securing the spiral wound element to the ATD. An optional O-ring in the groove 40 provides a circular seal capable of greatly inhibiting feed water by-pass, while the encasement traps 42 allow filling of the overcoat into the slots to firmly secure the ATD in place on the end of the spiral wound element. As shown in Figs. 1 A and IB, entrapment slots 43 may be equally spaced around the inner side of the outer peripheral edge of the ATD. In this embodiment, eighteen slots are provided, but the number may be varied as desired. The entrapment slots provide further securement of the spiral wound element by filling in of the overlay or overcoat.

[0057] The rim of the ATD preferably has a large bevel 44 on the inner periphery of the rim on the side facing the spiral wound element (inside edge). This large bevel allows feed water entry to outer leaf circumference areas. Further, the ATD, including the outer rim, may advantageously have a thickness in the longitudinal direction of about 0.75" (19 cm), which is slightly thinner than the standard 0.90" (23.0 cm) thick ATD.

[0058] As shown in Fig IB, the outside (brine side) surface of the ATD may have conventional vents 46, such as the eight equally spaced vents of about 0.02" (0.5 mm) deep. Between these vents, the outer surfaces 48 of the ATD provide potential sites for the etching of bar codes, serial numbers and/or other identification markings.

[0059] Further, on the inside surface of the peripheral rim, the ATD may have roughened areas 50 to enhance exterior encasement bonding of the element.

[0060] Turning to Figs. 5-8, there are shown handles (grasping or extracting devices) 52, 52'. These devices may be used for temporary engagement with ATDs of the invention for the purpose of carrying or otherwise handling the rather heavy, bulky and unwieldy spiral wound filtration elements to which the ATDs are attached. Thus, for example, for carrying and handling the spiral wound elements, a handle 52 may be engaged with the ATD at each end of the element, while for extracting a spiral wound element from a tubular vessel or insertion of an element into the vessel, a handle may be engaged with the ATD on the accessible end of the element for pushing or pulling the element in the desired direction.

[0061] According to one embodiment, the handle 52 generally comprises a central hub or shaft 54, curved or hooked legs 56 extending from the central shaft, and engagement feet 58 on the distal ends of the legs. The engagement feet 58 are designed and shaped to engage with the ledges or flanges 26 of the ATD to firmly hold the ATD with its attached spiral wound element. Preferably, the number of legs 56 and engagement feet 58 of the handle corresponds to the number of ribs 18 of the ATD. For engagement, the engagement feet 58 are inserted from the outside face into the large holes or spaces 21 between the ribs of the ATD, and the handle is then turned counter-clockwise, so that the free edges of the engagement feet 58 engage or lock with the ledges or flanges 26 of the ATD, as shown in Figs. 6A and 6B.

[0062] As shown in Figs 7A and 7B, a knob or grip 60 may be inserted into the central bore 55 of the shaft 54 for ease of carrying or handling the spiral wound element after engagement of the handle with the ATD on the end of the element. The knob or grip may have any desired shape and may be attached to the bore 55 of the shaft by a force-fit or friction- fit, for example.

[0063] As shown in Figs. 8A-8D, the handle 52' includes leg extensions 62 on the ends of the legs 56 for the purpose of allowing the handle to more easily reach into a tubular vessel to insert or extract a spiral wound element. The engagement feet 58 in this embodiment are attached to the ends of the legs extensions 62 for engagement with an ATD deep within the tubular vessel. Further, the central hub or shaft may rest in the interconnector 64 extending from the element to be inserted or extracted. Grip 60 may be replaced by a series of long shafts for reaching elements deep within a tubular vessel.

[0064] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the invention as defined by the appended claims.

Claims

We claim: 1. An anti-telescoping device for installing a spiral wound filtration element in a tubular pressure vessel, the device comprising a generally wagon wheel-shaped disc having:

an outer peripheral rim,

a central hub,

a plurality of ribs annularly spaced around the disc and connecting the peripheral rim with the central hub, and

a plurality of engagement catches each located at a transition of one of the ribs with the peripheral rim and adapted to receive radial projections of a handle for holding, installing or extracting the spiral wound filtration element.

2. The anti-telescoping device according to claim 1, wherein the engagement catches comprise flanges extending radially inwardly from the peripheral rim.

3. The anti-telescoping device according to claim 2, wherein the engagement catches comprise undercuts in angles of intersection between the peripheral rim and the ribs.

4. The anti-telescoping device according to claim 1 , wherein the disc has three to nine ribs.

5. The anti-telescoping device according to claim 4, wherein the plurality of engagement catches is equal in number to the number of ribs.

6. The anti-telescoping device according to claim 5, wherein the engagement catches engage with the handle by inserting the radial projections from an axial outer end of the disc into spaces between the ribs and rotating the handle in a plane parallel to the disc until the projections lock with the engagement catches.

7. A handle for holding, installing or extracting a spiral wound filtration element for a tubular pressure vessel, the handle comprising a plurality of annularly spaced legs extending radially outward and axially from a central holding portion, each of the legs having a radially outward extending foot at a distal end thereof, the legs being downwardly curved and/or hooked such that the feet lie in a different plane than the central holding portion, the feet being adapted to engage engagement catches in an anti-telescoping device on at least one end of the spiral wound filtration element.

8. The handle according to claim 7, wherein the central holding portion has a pilot guide extending axially therefrom in a direction of the feet, the pilot guide being adapted to engage an opening in a central hub of the anti-telescoping device for proper orientation of the handle.

9. The handle according to claim 7, wherein the central holding portion has a grip extending axially therefrom in a direction away from the feet for ambidextrous hand grasping.

10. The handle according to claim 7, wherein the feet are shaped and spaced to be inserted through the anti-telescoping device in spaces between ribs of the anti-telescoping device.

11. The handle according to claim 10, wherein the feet are shaped to lock on correspondingly spaced flanges on the anti-telescoping device when the handle is rotated in a plane parallel to the anti-telescoping device.

12. The handle according to claim 7, wherein the handle has three to nine legs and feet, the number of legs and feet corresponding to a number of ribs and spaces in the anti-telescoping device.

13. The handle according to claim 7, wherein the legs are adapted to be fitted with extensions, the extensions projecting axially from the distal end of each leg in a direction of the anti- telescoping device and the feet being attached to the distal end of each extension.

14. The handle according to claim 13, wherein the extensions have a length corresponding to a depth of the anti-telescoping device in the tubular pressure vessel.

15. An anti-telescoping device for installing a spiral wound filtration element in a tubular pressure vessel, the device comprising a generally wagon wheel-shaped disc having:

an outer peripheral rim,

a central hub, and

a plurality of ribs connecting the peripheral rim and central hub and annularly spaced around the disc,

the disc having at least one of the following features:

a) the peripheral rim having an outer diameter equivalent to approximately 7.94 inch for a nominal 8 inch inside diameter pressure vessel;

b) the disc having a maximum axial thickness of about 0.75 inch; c) the central hub having a central axial bore and a concentric counterbore providing a land for abutment of an end of a core tube of the spiral wound filtration element;

d) the ribs having hollowed out channels in a longitudinal direction thereof on a side of the disc facing the spiral wound filtration element;

e) the ribs having transverse notches on a side of the disc facing the spiral wound filtration element;

f) the peripheral rim having a smaller outer diameter portion on a side of the disc facing the spiral wound filtration element, wherein an outer radial face of the smaller diameter portion has annular grooves and spaced transverse notches for receiving encasement materials to secure the spiral wound filtration element to the anti-telescoping device; and

g) the hub having peripheral holes or grooves to facilitate repair of a core tube of the spiral wound filtration element.