Patent Application
20100237606
The present invention relates generally to piping and pipelines, and more particularly to end seals for pipeline assemblies with an outer casing pipe that circumscribes one or more inner transmission pipelines.
Conduit assemblies, such as pipelines and hydraulic circuits, are used to transport an assortment of fluids, such as water, oil, various natural and synthetic gases, sewage, slurry, hazardous materials, and the like. Modern day fluid pipelines are formed from a variety of materials, including concrete, plastic (e.g., polyvinyl chloride, polyethylene, etc.), and various metallic materials, such as iron, copper, and steel. The outer surface of metal pipes, when used in an outdoor application, is typically provided with a corrosion resistant coating.
In laying pipelines, many of the individual pipes are buried underground. Pipelines often pass under roadways, railroads, and other similar heavily loaded areas. To protect sections of pipeline that are buried underground, in particular those sections which pass under heavily loaded areas, and to avoid inadvertent leakage of gas or liquid from the pipeline, a rigid outer casing is generally provided around the buried sections of pipeline. The section of pipeline extending through the rigid outer casing is commonly referred to as the inner carrier pipe or “transmission pipeline”.
In many applications, end seals are provided at each end of the outer casing to prevent moisture, water, and contaminants from entering the annular space between the inner carrier pipe and the outer casing. For example, one prior seal arrangement consists of a bipartite, laminar metal end-cap, where the two pieces are assembled around the inner transmission pipeline, welded together to form a unitary body, and thereafter welded to the transmission pipeline and the outer casing. Another prior approach is to wrap rubber sheet material around the end of the outer casing, and thereafter fastening the opposite ends of the rubber sheet to the outer casing and inner carrier pipe with annular band clamps. Both of the aforementioned approaches have proven to be time consuming and costly, and have a limited operational life expectancy.
According to one exemplary embodiment, an end seal assembly is provided for sealing the space between an outer casing and at least one inner pipe that extends at least partially through the outer casing. The end seal assembly includes a seal member including a putty material configured to seal the space between the outer casing and the at least one inner pipe. The seal member is in sealing communication with, and extends between an exterior surface of the at least one inner pipe and an interior surface of the outer casing. A composite wrap covers at least a portion of the seal member. The composite wrap may include a fiberglass composite material.
According to another exemplary embodiment, an end seal kit is provided for sealing the space between an outer casing pipe and an at least one inner pipe extending at least partially through the outer casing pipe. The end seal kit includes a deformable sealing putty that is configured to extend between and mate with an exterior surface of the at least one inner pipe and an interior surface of the outer casing pipe to thereby create a fluid tight seal. The sealing putty comprises a non-cross-linked synthetic polyolefin. The end seal kit also includes a flexible wrap that is configured to surround the sealing putty. The flexible wrap comprises a continuous filament fiberglass cloth that is impregnated with a resinous pliable-plastic material operable to harden upon exposure to aqueous moisture.
In accordance with yet another exemplary embodiment, a method is presented for sealing the space between an outer casing pipe and at least one inner casing pipe that extends at least partially through the outer casing pipe. The method comprises applying a deformable sealing putty to at least one of the outer casing pipe or the at least one inner pipe. The method also comprises forming the sealing putty into a fluid tight seal that extends between an exterior surface of the inner pipe and an interior surface of the outer casing pipe. The seal has a seal body with an annular segment disposed within the casing pipe, and a frustoconical segment that extends generally coaxial from one side of the annular segment outside of the outer casing pipe. The method further comprises wrapping a flexible composite wrap around the frustoconical segment of the seal, and curing the flexible composite wrap.
The above summary of the invention is not intended to represent each embodiment, or every aspect, of the present invention. The above features and advantages, and other features and advantages of the present invention, will be readily apparent from the following detailed description of the preferred embodiments and best modes for carrying out the present invention when taken in connection with the accompanying drawings and appended claims.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Referring to the drawings, wherein like reference numbers refer to like components throughout the several views,
The fluid pipeline assembly 10 includes an outer casing 14 (also referred to herein as “outer casing pipe”). The outer casing 14 is employed to protect that portion of a transmission pipeline 16 (also referred to as “inner pipeline” or “inner pipe”) which extends at least partially through the outer casing 14. The outer casing 14 may be constructed of any feasible material having sufficient strength to withstand, for example, external loads exacted thereon, such as those that exist by reason of a surrounding formation (e.g., when the pipeline assembly is buried underground), as well as any additional loads applied thereto (e.g., by a vehicle driving along an over-passing roadway). In addition, the outer casing 14 may be constructed of an impervious material capable of minimizing or otherwise preventing the seepage of fluids into and out of an annular space, designated generally as 18, between the outer casing 14 and the inner pipe 16 passing therethrough. It is also contemplated that the various embodiments of the present invention be applied to all pipeline assemblies, such as, but certainly not limited to, new constructions and above-ground cased pipe assemblies. It is contemplated that, in certain embodiments, the outer casing and/or the inner pipe are formed, for example, from steel, iron, concrete, or fiber-reinforced plastic (FRP) or combination thereof.
To prevent inadvertent contact between the outer casing 14 and inner pipe 16, the inner pipe 16 may be spaced from the outer casing 14 and retained in place by spacers or runners (neither of which are illustrated herein). To this regard, the outer casing 14 and inner pipe 16 are shown in
In accordance with one embodiment, an end seal assembly 12 is located at either end of the outer casing 14 (only one of which is visible in
In the exemplary configuration presented in
The frustoconical seal member 20 is configured—e.g., chemically and/or mechanically—to seal one end of the annular space 18 defined by the outer casing 14 and inner pipe 16. For example, the frustoconical seal member 20 shown in
Referring to
In addition to the above noted parameters, the annular segment 26 of the seal member 20 has a longitudinal length L2 (also referred to herein as “packing depth”). In this regard, the seal member 20 is formed such that the packing depth L2 of the annular segment 26 is approximately half the taper length L1 of the frustoconical segment 24. For example, if the taper length L1 of the frustoconical segment 24 is four (4) inches (10.16 cm), the packing depth L2 of the annular segment 26 is approximately two (2) inches (5.08 cm).
In the embodiments illustrated in
The composite wrap 40 provides a functional cocoon for the seal member 20, creating a structurally reinforcing, water-tight shield. In one embodiment, the composite wrap 40 is fabricated from a fiberglass composite material, such as, for example, a continuous filament fiberglass cloth that is impregnated with a resinous pliable-plastic material. A composite wrap of this construction can be hardened by exposure to aqueous moisture (e.g., water). One such fiberglass composite wrap is disclosed in commonly assigned U.S. Pat. No. 5,030,493, to Rich, which is incorporated herein by reference in its entirety. In certain embodiments, the composite wrap 40 includes a plurality of layers of fiberglass composite material, preferably in the range of eight (8) or more layers. In some embodiments, the seal member 20 and composite wrap 40 cooperatively create a fluid-tight seal with sufficient integrity and resiliency to withstand a pressure of at least five (5) pounds per square inch (psi) (34.47 kPa), and in some embodiments at least seven (7) pounds per square inch (psi) (48.26 kPa), within the space 18 between the outer casing 14 and inner pipe 16. In an alternative configuration, the composite wrap 40 may comprise a cloth that is impregnated by a resin that is set by UV light, or thermoset (heat), or by mixing one part of the resin with another compound (e.g., a catalyst) causing the resin to set and harden.
In the exemplary embodiment illustrated in
Referring now to
The end seal kit 50 presented in
In addition to the sealing putty 52 and flexible wrap 54, the end seal kit 50 may further comprise an elastic wrap 56 of sufficient length and width to surround the flexible wrap 54 and preferably at least a portion of the inner pipe(s) and outer casing pipe immediately adjacent to the casing pipe end seal. By way of example, and not limitation, the elastic wrap 56 may comprise a perforable polyethylene film or similar material. When properly applied, the elastic wrap 56 (also referred to as a “compression film”) applies pressure to the flexible wrap 54.
It is contemplated that in certain embodiments the elastic wrap 56 can be configured to evacuate gas that may result from curing of the fiberglass composite wrap 54, and build up underneath the elastic compression wrap 56. In this regard, the end seal kit 50 may be equipped with a perforator tool, shown in one exemplary configuration at 58. The perforator tool 58 of
With continued reference to
The other components of the end seal kit 50 of
The pipe roughening device 24 may be a wire brush (as seen in
Many of the above indicated components are considered optional, such as the perforator tool 58, protective gloves 66, pipe roughening device 68, cleaning solvent 70, and solvent wipe 72, and are therefore not necessary components of the end seal kit 50. It should also be readily recognized that the constituent parts of the end seal kit 50 may be varied within the scope of the appended claims. In particular, the end seal kit 50 may comprise additional, fewer, or alternative components from those which are illustrated in
With reference now to the flow chart of
In situations where the pipeline assembly 10 is buried prior to formation of the pipeline casing end seal 12, the outer casing 14 and inner pipeline 16 should be excavated sufficiently on both sides, as recited in step 101. Proper safety considerations aside, the pipeline assembly 10 may be considered sufficiently excavated so that the pipes 14, 16 can be initially inspected, and thereafter properly handled during fabrication of the end seal. Accordingly, in step 103, both the outer casing 14 and the inner pipe 16 are checked for any of an array of predetermined deterioration characteristics. Such characteristics may include, but are certainly not limited to, considerable wall loss (i.e., excessive deterioration of a pipe wall), significant pipe contact, inadequate remaining pipe coating, etc. If it is determined that one or more of these characteristics is present, the operator should preferably take appropriate action. Such action may include repairing one or more of the pipes if there is heavy wall loss, or merely coating the pipe if there is minimal wall loss. In addition, if there is significant pipe contact, the operator may dig up the pipeline assembly some additional distance, and reset the pipe to eliminate inadvertent casing-to-pipe contact.
Prior to fabrication of the pipeline casing end seal, the application surfaces of the outer casing and inner transmission pipe are prepared in step 105 of the embodiment illustrated in
Initially, the operator should attempt to remove all foreign matter on the application surfaces of the outer casing and inner transmission pipe. This may include removal of nearly all pipe coatings, mill scale, rust, rust scale, paint, and other foreign matter by the use of abrasives, such as pipe roughening device 68. In certain embodiments, a near-white blast cleaned surface finish can be achieved, wherein which all oil, grease, dirt, mill scale, rust, corrosion products, oxides, paint and other foreign matter has been substantially removed from the surface except for very light shadows, very slight streaks, or slight discolorations caused by rust stain, mill scale oxides, or light, tight residues of paint or coating that may remain.
Subsequently, a solvent wipe, such as cloth 72 of
Once the application surfaces have been adequately cleaned, an anchor pattern can be fashioned into the interior surface 15 of the outer casing pipe 14 and the exterior surface 17 of inner pipe prior 16. A high-pressure water blast, desirably in the range of approximately 20 to 48 MPa (3,000 to 7,000 psi), may be used to create the anchor pattern. The recommended surface preparation of the casing pipe 14 and transmission pipeline 16 is an anchor pattern with a 0.0254-0.1016 mm (1-4 mils) etching depth.
In some embodiments, a rigid or semi-rigid backing wall 114 can be then constructed inside of the outer casing 14, as illustrated in
To ensure that the seal assembly 112 will provide sufficient seal strength to withstand an expected pressure buildup within the inner space between the pipes 14, 16, a coating 118 of epoxy or resinous substance can be applied to the backing wall 114. The coating 118 extends from the inner surface 15 of the outer casing 14 to the outer surface 17 of the inner pipe 16, providing a generally complete cover of the backing wall 114. The coating 118 may extend onto the inner and outer surfaces 15, 17, providing a seal once set. In addition, or as an alternative, the resinous/epoxy coating 118 can be applied to the frustoconical segment 24 of the seal body 22 or on the outer surface of the composite wrap 40 (see, e.g., FIGS. 1A-D),.
Once the surface preparation has been completed, a corrosion-prevention sealing putty will be applied within open end of the casing pipe 14. In the embodiment presented in
In one exemplary application, the sealing putty 52 may be applied (by hand packing or other comparable methods having a similar end-result) to the bottom of the casing pipe 14, working upward to ensure a recommended volume of putty 52 is used. As described above with respect to the end seal annular segment 26 of
The deformable sealing putty 52 can be used to taper the transition from the casing pipe 14 to the transmission pipeline 16. As explained above with respect to the frustoconical segment 24 of the seal member 20 illustrated in
With continuing reference to the embodiment of
During installation, it can be desirable for the composite wrap 54 to be wet on substantially all surfaces. Prior to laying the composite wrap 54, an operator may immerse the fiberglass composite wrap 54 in an open container of water, preferably for at least 30 seconds, while preferably turning and squeezing lightly to wet as much area of the wrap 54 as possible. Alternatively, the composite wrap 54 may be placed over the putty-based seal member 20, and sufficient aqueous moisture be applied thereafter to catalyze the resinous pliable-plastic material contained within the continuous filament fiberglass cloth. Notably, once the composite wrap 54 has been exposed to moisture, there is approximately a 20-30 minute working window within which the wrap 54 must be set, depending upon ambient working temperatures.
The operator may begin the lay up on the putty-based seal member 20, either with each layer directly over the previous layers, or in a spiral bias method with an approximately 50% or so overlap. It is contemplated that the composite wrap 54 be installed smoothly to minimize any unintentional bunching. Moreover, the composite wrap material may be consistently pulled tight, and smoothed from the center out in the direction of the roll. Care can be taken to remove/minimize air spaces and voids between the individual layers of wrap 54. Good adhesion between the layers can be accomplished with consistent pressure and firmly smoothing of the layers with the open palm of the hand in the direction the fiberglass composite wrap 54 is being applied. While applying the wrap 54, it can be desirable for tiny droplets of water to be visibly squeezing through the fiberglass weave of the fiberglass fabric. If there is a lack of such visible droplets, more activating water can be misted over the exposed surfaces of the composite wrap 54 before continuing with wrapping.
The roll of composite wrap 54 can be unwrapped beyond the contact point to ensure correct placement and lay-up. In addition, the composite wrap 54 can be cut in place to eliminate voids or blisters where inconsistent surfaces or obstacles dictate. If the composite wrap 54 is cut, the restarted cut end should overlap the installed end by half the width of the roll. In certain embodiments, a minimum application of eight (8) layers of composite wrap 54 is recommended, although some applications may require fewer or more than 8 layers. In other embodiments more than 15 layers may be required for a particular application, for which a set time of approximately 45 minutes or so may be allowed to lapse between applications of each 15-layer phase.
After the composite wrap 54 has been installed, the end seal assembly 20—i.e., the putty-based seal member 20 encased within the composite wrap 40 seen in
As indicated in step 113, the composite wrap 40 is allowed to dry (i.e., cure) and the elastic compression wrap 56 removed after a predetermined period of time. The composite wrap 54, namely the fiberglass cloth impregnated with a resinous pliable-plastic material, will “out-gas” and bubble for approximately 1-2 hours after installation depending upon temperature; this is a normal part of the curing process. In one example, the composite wrap 40 is allowed to dry for approximately 30 minutes (e.g., at ˜95° F.). In another example, the composite wrap 40 is allowed to dry for approximately 60 minutes (e.g., at ˜75° F.). In yet another example, the composite wrap 40 is allowed to dry for approximately 150 minutes (e.g., at ˜55° F.).
Applying the top coating:
It is contemplated that the fiberglass composite wrap be allowed to properly cure before the topcoat 60 is applied. Once the elastic compression wrap 56 is removed and the composite wrap 54 has cured, the topcoat 60 is applied thereto in step 115, preferably covering and encapsulating the entire end seal assembly 12. The pipeline assembly can buried after 4 hours if applicable.
The method 100 may include at least steps 101-115. However, it is within the scope and spirit of the present invention to omit steps, include additional steps, and/or modify the order presented in
While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/162,077, filed on Mar. 20, 2009, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61162077 | Mar 2009 | US |
