SYSTEM AND METHOD FOR PIPELINE COATING

A coating system to coat the interior of a pipeline section using a UV curable coating and an internally pressurized UV foil that assists in suspending and distributing coatings during UV curing. The UV foil may be installed through the length of the pipeline section using an inversion system driven by pressurized air. The system includes a coating delivery system for distributing the coating along the interior of the pipe. The system includes a UV light source capable of delivery sufficient UV light to cure the coating. The UV light source may include a light train having a plurality of UV light sources, such as UV light emitting diodes, carried by a motorized trolley. The coating system includes an inlet adapter that facilitates inversion and pressurization of the UV foil, as well as introduction of the UV light source into the interior of the pressurized UV foil.

BACKGROUND OF THE INVENTION

The present invention relates to pipeline coating and more particularly to systems and methods for internal coating of installed pipeline while the pipeline remains installed.

Pipeline coating is often paramount when maintaining a system for operation. While repairs options can be abundant, or limited depending on pipeline size, application and timing, epoxy coatings have been used for years, both internally and externally, as means for remediation. Typical coatings consist of a two-part component that is mixed, placed and often ambient cured. Curing can be accelerated in a variety of ways, but is typically not controllable.

There has been some use of UV curable epoxy in pipeline rehabilitation. However, known technologies using UV based epoxy for pipeline rehabilitation are typically associated with cure-in-place pipe (“CIPP”) relining. These technologies conventionally use a felt or fiberglass impregnated tube as a carrier that is used to renew structurally compromised pipelines—predominantly storm and sewer applications. The resin/felt matrix together provides structural strengthening and renewal. Liners associated with CIPP relining are pulled-in-place using mechanical winches, inflated and cured to provide a PIPE WITHIN A PIPE. Most CIPP installations have significant ID reduction, do not bond to the host pipe and have limitations related to pipeline configuration, fittings and lengths. This technology in concept or delivery does not correlate to many markets, purposes, industries or applications.

SUMMARY OF THE INVENTION

The present invention provides a coating system for internally coating a section of pipeline using a UV curable coating. The coating system includes UV foil that assists in suspending and distributing coatings over the interior surface of the pipeline section prior to and during UV curing. The UV foil may be installed through the full length of the pipeline section to receive the coating. The UV foil may be installed using an inversion system that drives the UV foil into pipeline using a pressurized fluid, such as pressurized air. The coating system includes a pressure system, such as a source of compressed air, for internally pressurizing the UV foil. A single pressure system may be provided to invert and internally pressurize the UV foil.

In one embodiment, the coating system includes a coating delivery system for distributing the coating along the interior of the pipe. In one embodiment, the coating delivery system may be a spin-cast coating delivery system that moves through the pipe and distributes the coating as it travels. In some applications, movement of the spin-cast coating delivery system through the pipeline section may be automated. In other applications, movement may be manual.

In one embodiment, the coating system also includes a vacuum system for applying a vacuum inside the pipeline section external to the UV foil. The vacuum system may be situated downstream from the UV foil insertion location.

In one embodiment, the coating system includes a UV light source capable of delivery sufficient UV light to cure the coating. In one embodiment, the UV light source includes a light train having a plurality of UV light sources, such as UV light emitting diodes, carried by a motorized trolley.

In one embodiment, the coating system includes a camera system. The camera system may be integrated into the light train trolley or may be provided separate from the trolley. The camera system may include a camera that is carried ahead of the light source to allow visual inspection of the pipeline section prior to curing. The camera may be coupled to a display that is located where it is readily visible to an operator.

In one embodiment, the system includes an inlet adapter that facilitates inversion and pressurization of the UV foil, as well as introduction of the UV light source into the interior of the pressurized UV foil. The inlet adapter may be secured to the upstream end of the pipeline section, for example, using a compression fitting. The inlet adapter may be a double-cylinder inlet adapter having a first cylinder for introducing the UV foil into the pipeline section and a second cylinder for introducing a light source into the UV foil.

In one embodiment, the system includes a termination cap configured to be fitted to the downstream end of the pipeline section. The termination cap may be secured to the downstream end of the pipeline section, for example, using a compression fitting. The coating system may be introduced into the interior of the pipeline section through the termination cap. The termination cap may include an air/vacuum inlet, which allows a vacuum to be drawing within the pipeline section.

In another aspect, the present invention provides a method for coating a pipeline section including the general steps of applying a UV-curable coating to the interior of a pipeline section; installing a UV foil inside the pipeline section; internally pressurizing the interior of the UV foil to urge the UV foil into contact with the interior wall of the pipeline section with sufficient force to assist in distribution and retaining the coating in an even layer; subjecting the coating to UV light applied by a UV light train configured to travel through the interior of the pipeline section while the UV foil remains under internal pressure and removing the UV foil.

In one embodiment, the method includes the steps of fitting the open end of the UV foil over the upstream end of the host pipe and installing the inlet adapter over the open end of the UV foil and the upstream end of the host pipe. In this embodiment, the inlet adapter retains the open end of the UV foil over the upstream end of the host pipe in such a way as to allow the UV light train and/or camera to be introduced into the pressurized interior of the UV foil.

In one embodiment, the method includes the step of inverting the UV foil into the pipeline section, pressurizing the interior of the UV foil via the inversion system, closing the gate valve on the UV foil inversion tube, opening the gate valve on the main tube before or after pressurizing the interior of the UV foil and maintaining pressure in the interior of the UV foil via the main tube.

In one embodiment, the method includes the step of closing the gate valve in the main tube, opening the main tube access cap, introducing a light train or camera into the interior of the main tube, opening the gate valve in the main tube and introducing the light train or camera into the interior of the UV foil.

In one embodiment, the method may include the step of inspecting the pipeline section using a camera system configured to travel through the interior of the pipeline section. The camera may be carried on a trolley and may provide video to a display located near an operator. The camera system may be used to inspect the interior of the pipeline section at various times during the coating process. More specifically, the camera system may be used to inspect the interior of the pipeline prior to or after essentially any step in the method.

In one embodiment, the method may include the step of preparing the pipeline section for coating using a preconditioning head configured to travel through the interior of the pipeline section. The preconditioning head may be a pipeline pig configured to scape, brush or otherwise condition the interior surface of the pipe. The preconditioning head may have active elements configured to mechanically abrade or otherwise condition the interior surface of the pipeline, for example, high pressure fluid, sandblasting, wire brushes or other abrasive mechanisms.

In one embodiment, the method may include the step of applying a vacuum to the downstream end of the pipeline section to assist in removing voids and uniformly distributing the coating. The vacuum may be introduced through a termination cap that is position downstream from the UV foil.

The present invention provides a highly reliable system and method for applying coating to pipeline sections. The use of UV-curable coatings allows controlled curing of the coatings, which in turn provides a finished coating of significantly higher quality and consistency. The UV foil helps to provide and maintain uniform distribution of the coating before and during curing. The use of an external vacuum can provide a number of benefits. For example, the vacuum may help to invert and draw the UV foil into proper position within the pipeline section. Further, the vacuum may assist in removing air pockets trapped between the UV foil and the coating, thereby improving quality and uniformity of the coating. The inlet adapter provides a simple and effective structure for introducing the UV foil and light train into the pipeline section and for maintaining pressure in the interior of the UV foil. The outlet adapter provide a simple and effective structure for closing the downstream end of the pipeline section in such a way as to allow introduction of a coating delivery system and application of a partial vacuum.

DESCRIPTION OF THE CURRENT EMBODIMENT

The present invention is directed to a system and method for coating the interior of pipeline sections. In the illustrated embodiment, the coating system10generally includes an inlet adapter12, a termination cap14, a coating delivery system16, a UV foil18, a foil inversion system20and a UV light source22(SeeFIGS. 4 and 7). The coating system10may also include a camera system24to facilitate visual inspection of the interior of the pipeline section.FIG. 1is an illustration of a pipeline section200fitted with an inlet adapter12and a termination cap14in accordance with an embodiment of a coating system10of the present invention. During use of the illustrated embodiment, a coating26is applied to the interior of the pipeline section10using the coating deliver system16. The coating delivery system16may be introduced into the pipeline section200via the termination cap14. A UV foil18is then introduced into the interior of the pipeline section200via a UV foil inversion tube30integrated into the inlet adapter12. The UV foil18is internally pressurized to urge the UV foil18outwardly into contact with the uncured coating26. The pressure is sufficient for the UV foil18to assist in distributing and retaining the coating26in a uniform layer over the interior of the pipeline section200. The UV light source22is then introduced into the interior of the pipeline section200and moved through the interior of the UV foil18along the length of the pipeline section200to cure the coating26. The UV light source22may be introduced into the pipeline section200via the inlet adapter12.

For purposes of disclosure, the terms “upstream” and “downstream” are used as relative terms to describe directions relative to the longitudinal length of the pipeline section. The term “upstream” relates to a direction toward the end of the pipeline section through which the UV foil is introduced into the pipeline section and the term “downstream” refers to a direction toward the opposite end of the pipeline section. These terms are used without reference to the direction through which fluid passes through the pipeline during normal use. Further, directional terms, such as “vertical,” “horizontal,” “top,” “bottom,” “upper,” “lower,” “inner,” “inwardly,” “outer” and “outwardly,” are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. The use of directional terms should not be interpreted to limit the invention to any specific orientation(s).

B. Coating System

The present invention is described and illustrated in the context of an exemplary pipeline section. The present invention may be used in a wide variety of pipeline sections of different sizes and shapes. For example, the inlet adapter, termination cap and UV foil may be scaled to accommodate the inner and outer diameters of the pipeline section to be coated. Similarly, the coating delivery system and UV light source may be integrated into carriers that are appropriate for the applicable pipeline section. In some applications, these components may be carried by trollies or pigs configured for use pipeline sections of the corresponding internal diameter. Although the illustrated pipeline section is straight, the present invention may be implemented in pipeline sections that are not straight. In pipeline sections with significant curves or bends, it may be desirable to make accommodations in the components that travel through the interior of the pipeline section to facilitate navigation through such curves or bends.

The coating system10ofFIGS. 1-6generally includes an inlet adapter12, a termination cap14, a coating delivery system16, a UV foil18, a foil inversion system20and a UV light source22. The coating system10may also include a camera system24to facilitate visual inspection of the interior of the pipeline section200. In some embodiments, the coating system10may further include a vacuum system94to draw a partial vacuum within the interior of the pipeline section200.

FIG. 1is an illustration of a pipeline section200fitted with an inlet adapter12and a termination cap14in accordance with an embodiment of a coating system10of the present invention. The pipeline section200has an upstream end202, a downstream end204and an interior surface206that defines a pipeline section interior208. The illustrated pipeline section200is merely exemplary and the present invention may be used to apply coatings to a wide range of pipeline sections of different sizes and shapes. The illustrated embodiment shows a straight pipeline section of uniform inner and outer diameters. The present invention may be used to apply coatings to pipeline sections that are not straight and that have variations in inner and/or outer diameter.

The inlet adapter12is generally configured to close off the upstream end202of the pipeline section200and to allow selective introduction of the UV foil18and the UV light source22into the interior of the pipeline section200. The inlet adapter12may also allow introduction of a camera into the interior of the pipeline section200. The inlet adapter12of the illustrated embodiment generally includes a main tube28and a UV foil inversion tube30. In this embodiment, the main tube28generally corresponds with the diameter of the host pipe (pipeline section200). The main tube28generally includes a cylinder32having a mounted end34secured to pipeline section200and a free end36that is opposite the mounted end34, a primary access cap38closing the free end36of the cylinder32, a secondary access cap40disposed within the primary access cap38, a gate valve42and an air inlet44. The main tube28may also include a pressure gauge46. The free end36of the cylinder32is connected to the upstream end of the pipeline section200, for example, by a compression fitting, adaptor or other similar component. The gate valve42is situated toward the longitudinal center of the cylinder32and is configured to selectively isolate an upstream segment of the cylinder32from a downstream segment of the cylinder32. In the illustrated embodiment, the position of the gate valve42is selected so that the upstream segment of the cylinder32is of sufficient length to accommodate the UV light source22and/or the camera of camera system24. The position of the gate valve42may vary from application to application as desired. The gate valve42may be replaced by other types of valves. In this embodiment, the air inlet44and pressure gauge46are disposed in the upstream segment of the cylinder32. The air inlet44may be coupled to a supply of pressurized air, such as compressor98.

The UV foil inversion tube30intersects with the main tube28upstream from the mounted end34of the cylinder32. The UV foil inversion tube30generally include a fixed end48joined to the main tube28and a free end50opposite the fixed end48. A gate valve52is situated in the UV foil inversion tube30. The position of the gate valve52in the UV foil inversion tube30may vary. The gate valve52may be replaced by other types of valves. The UV foil inversion tube32may also include a pressure gauge54to assist during operation. The free end50of the UV foil inversion tube30is configured to be operatively coupled to the UV foil inversion system20. As described in more detail below, the UV foil inversion system20may be a conventional cast in place pipeline (“CIPP”) air inversion system.

The termination cap14is configured to mount the downstream end of the pipeline section200. Generally speaking, the termination cap14is configured to close the downstream end of the pipeline section200while facilitating introduction of the coating delivery system16. In some applications, the termination cap14may be configured to also allow removal of the UV foil and/or the application of a downstream vacuum to the interior of the pipeline section200. The termination cap14generally includes a main tube60having a mounted end62affixed to the pipeline section and a free end64opposite the mounted end62, a termination access cap66and a gate valve68. The mounted end62of the termination cap14may be mounted to the downstream end of the pipeline section200by a compression clamp, adaptor or other similar component capable of providing a leaktight connection. The gate valve68may be replaced by other types of valves. In applications where it is desirable to introduce a partial vacuum to the downstream end of the pipeline section200, the termination cap14may also include an air/vacuum inlet70. A pair of pressure gauges72and74may also be provided on opposite sides of gate valve68.

The design and configuration of the termination cap may vary from application to application. For example, an alternative termination cap14′ is shown inFIGS. 7 and 8. In this embodiment, the termination cap14′ includes a cylinder60′ that is closed by an access cap66′. The access cap66′ of this embodiment includes an inlet port70′ through which a vacuum can be drawn in the downstream end of the pipeline section200. For example, the vacuum port70′ may be coupled to a vacuum source. Additionally, the inlet port70′ may provide an opening through which accessories may be fed into the interior of the pipeline section200. For example, supply lines associated with the coating delivery system and/or winch cables associated with a trolley (e.g. a camera trolley and/or a UV light source trolley) may be fed into the pipeline section200through the inlet port70′. A pressure gauge72′ may also be included to assist in maintain the proper pressure in the downstream end of the pipeline section200.

The UV foil18is a flexible tubular structure that is of sufficient length to extend through the full length of the pipeline section200. To facilitate inversion, the UV foil18includes an open end76and a closed end78. The closed end78of the UV foil18may be closed by rolling and clamping or any other suitable method. During assembly, the open end76is fitted over the host pipe (pipeline section200) and secured by installation of the inlet adapter12. The remainder of the UV foil18, including the closed end78, is coiled in the inversion system. Pressurized air is used to invert the UV foil18and move it through the pipeline section200. Once fully installed, the UV foil18will be fully inverted and the closed end78will be situated at the downstream end of the pipeline section200, for example, in termination cap14. The UV foil18may be manufactured from a wide range of alternative materials, such as clear plastic, latex, nitrile, neoprene or equivalent material. The UV foil18material should be sufficiently transparent to UV light to allow the light from the light source to pass through the UV foil18to cure the coating26, and should have the strength to withstand the pressure boundaries associated with the coating process. For example, the UV foil18should be capable of withstanding inversion and internal pressurization pressures between 3-10 psi. This pressure range is merely exemplary and pressures outside this range may be used in alternative applications. For example, higher pressures may be used in smaller diameter pipeline sections or when additional pressure is useful in distributing or suspending the coating26. The amount of elasticity in the UV foil may vary from application to application. In some applications, the UV foil18may be essentially inelastic in response to the anticipated internal pressure. However, the UV foil18may be manufactured from an elastic material that undergoes significant expansion as the UV foil18undergoes internal pressurization. In the illustrated embodiment, the UV foil18is configured to be removed from the pipeline section200after curing. To facilitate this, the UV foil18may be manufactured from a material that does not become permanently bonded to the coating26or coated with a material that prevents the UV foil18from permanently bonding tot the coating26. In some applications, it may be desirable to use a winch cable or other similar lead line to assist in moving the UV light source22(or other components, such as the camera) through the UV foil18. For example, in the illustration ofFIG. 7, the UV light source22is traversed through coated pipeline within the pressurized UV foil18with the assistance of a winch cable19that extends out the downstream end204of the pipeline section200. The UV foil18may include a rubberized grommet (not shown) or other similar component to accommodate passage of the winch cable19through the UV foil's termination. Overcoming air passage is accomplished by CFM differential.

The UV foil inversion system20of the illustrated embodiment is a generally convention CIPP air inversion system. A variety of suitable inversion systems are commercially available. For example, inversion guns from Perma-Liner, CIPP Services, or an array of other suppliers may be incorporated into the present invention. In the illustrated embodiment, the UV foil inversion system20may include a conventional air inverter shooter/gun82. The air inverter shooter82may include a UV foil inlet84for delivering UV foil18into the shooter, a manifold portion86and UV foil outlet88for introducing the UV foil18into the UV foil inversion tube30. The UV foil outlet88is coupled to the free end of the UV foil inversion tube30. The manifold portion86is coupled to a source of pressurized air (such as an air compressor90) so that pressurized air can be supplied to the manifold portion86to invert the UV foil18. The UV foil inversion system20may also include a UV foil take-up reel92that stores the UV foil18on a reel prior to inversion and feeds the UV foil18into air inverter shooter82during the inversion process. The reel92may be free spinning so that the introduction of air into the manifold portion86automatically and progressively feeds UV foil18from the reel92to the interior of the pipeline section200. Air inverter shooter82and reel92are merely exemplary and may be replaced by essentially any equipment capable of inverting the UV foil18into the pipeline section200.

In some applications, the coating system10may include a vacuum system94to draw a partial vacuum on the downstream end of the pipeline section200. The vacuum system94may include essentially any vacuum source. For example, the vacuum source may be a generally conventional air compressor94that is coupled to vacuum inlet70and is configured to withdraw air from the downstream end204of the pipeline section200(SeeFIG. 9).

The coating delivery system16may be essentially any coating delivery system capable of distributing the coating26on the interior of the pipeline section200with sufficient uniformity for the action of the pressurized UV foil18to yield a uniform and void free coating. A variety of suitable coating delivery systems are commercially available. For example, the CoverCat spray system by Covercat or Spin-Kote units from Clemco may be incorporated into the present invention. In the illustrated embodiment, the coating delivery system16is a generally conventional spin-cast delivery system configured for internal pipeline use. The spin-cast delivery system16includes delivery head80that is movable through the interior of the pipeline section200(SeeFIG. 4). The delivery head80may be moved from the interior of the pipeline section200manually or through the use of automation, such as a trolley81(motorized or manually moved). The spin-cast delivery system16is merely exemplary and the present invention may include essentially any coating delivery system capable of adequately distributing coating over the interior of the pipeline section200.

The present invention may be used to apply a wide range of coatings. In the illustrated embodiment, the coating26is a UV-cured epoxy with physical and chemical properties selected to achieve the desired functional purpose on the interior of the pipeline section200and to make the coating26appropriate for spin-cast delivery. The epoxy may include a UV catalyst that catalyzes curing when subjected to an adequate amount of UV light and/or a UV inhibitor that retards curing until the UV inhibitor is deactivated by an adequate amount of UV light. Although the described coating26is an epoxy, the coating system10may be used to apply other types of coatings. For example, the present invention may be used to apply urethane coatings, such as UV-curable polyurethane acrylates.

The UV light source22is generally configured to travel through the interior of the pipeline section200and the interior of the UV foil18, and to emit sufficient UV light to cure the coating26while the coating26is suspended by the UV foil18. The UV light source22may be include essentially any UV light source capable of producing sufficient UV light to transmit through the UV foil18and cure the suspended coating26. A variety of suitable UV light sources are commercially available. For example, the UV light source22may a plurality of UV light emitting diodes (“LEDs”) arranged to form a light train. The number and type of UV LEDs incorporated into the UV light source22may vary from application to application depending on the UV transparency of the UV foil18and the UV-curing properties of the coating26. In use, the UV light source22may be moved through the interior of the pipeline section manually or using automation. For example, the UV light source22may be mounted to a motorized trolley96that is capable of traveling through the interior of the pipeline section200. A variety of suitable trolleys are commercially available. For example, the Anaconda by Aries Industries, Inc. or Power Light by IST, Inc. may be incorporated into the present invention. As an alternative to the use of a motorized trolley, the UV light source may be mounted to a pig or non-motorized trolley that can be manually moved through the interior of the pipeline section200.

In some applications, the coating system10may include a camera system24configured to travel through the interior of the pipeline section200. For example, the camera system24may be a conventional CCTV system with a camera25that transmits video/images to a display27that is located where it is readily visible to an operator. The camera25and display27may be coupled by wires/cord29or through the use of wireless communications. In the illustrated embodiment, the cord29is routed through the secondary access cap40, which includes a compression cap41and a gasket43(e.g. rubber gasket) that provide a leaktight seal around the cord29. In use, the secondary access cap40allows the cord29to feed into and out of inlet adapter12as the camera25travels through the pipeline section200. The camera system24may be integrated into the light train trolley96, carried by a dedicated camera trolley or provided without a trolley. When integrated into the trolley96, the camera may be mounted ahead of the light source to allow visual inspection of the pipeline section prior to curing. A light shield (not shown) may be situated between the UV light source and the camera to confine the UV light to prevent premature curing of the coating26.

In some application, the coating system10may include a pipeline reconditioning system to prepare the interior of the pipeline section200to receive the desired coating26. For example, the pipeline reconditioning system may be configured to clean and profile the interior of the pipeline section200. The pipeline reconditioning system may include one or more reconditioning heads selected to prepare the interior surface206of the pipeline section200as desired for proper adhesion of the coating26. For example, the preconditioning head may be a pipeline pig configured to scape, brush or otherwise condition the interior surface206. The preconditioning head(s) may have active elements configured to mechanically abrade or otherwise condition the interior surface of the pipeline, for example, high pressure fluid, sandblasting, wire brushes or other abrasive mechanisms.

C. Coating Method

As noted above, the present invention may be used to provide uniform and high quality coatings to the interior of pipeline sections, such as pipeline section200. The coating system10discussed above may be used to implement a coating method that includes the following general steps: (a) applying a UV-curable coating26to inside of pipeline section200, (b) installing the UV foil18in the interior208of the pipeline section200, (c) pressurizing UV foil18, (d) moving a UV light source22through the interior of the pressurized UV foil18to cure the coating26and (e) removing the UV foil18after the coating26is sufficiently cured. The method and variations options, including additional and alternative method steps, are described in the following paragraphs.

In the illustrated embodiment, the inlet adapter12and termination cap14are installed on opposite ends of the pipeline section200. The inlet adapter12of this embodiment is fitted over the upstream end202of the pipeline section200and secured using any suitable structure, such as a compression fitting. The termination cap14of this embodiment is fitted over the downstream end204of the pipeline section200and secured using any suitable structure, such as a compression fitting. Although useful in providing an airtight enclosure when a vacuum will be applied to the downstream end204of the pipeline section200, the termination cap14is optional and may be eliminated when not desired.

In the illustrated embodiment, the upstream end of the UV foil18is installed simultaneously with the inlet adapter12. More specifically, in the illustrated embodiment, the open upstream end76of the UV foil18is fitted over the upstream end202of the host pipe, pipeline section200(SeeFIG. 5). The inlet adapter12is then fitted over the upstream end202of the host pipe (pipeline section200) and the upstream end of the UV foil18. The inlet adapter12is then secured to the pipeline section200by a compression fitting or other similar structure. Installing the compression fitting not only secures inlet adapter12, but also clamps the upstream end of the UV foil18.

The gate valves42,52and68may be used to assist in carrying out different method steps. For example, gate valve42in the main tube28may be used to isolate the upstream portion of the main tube28from the interior of the pipeline section200. When the gate valve42is closed, the primary and secondary access caps38and40can be opened without impacting air pressure within the pipeline section200. In use, the gate valve42can be closed when introducing and removing components, such as the camera and/or the UV light source, into the main tube28. If desired, the upstream portion of the main tube28can be re-pressurized to correspond with internal pressure before re-opening the gate valve42. For example, pressurized air may be introduced into the upstream portion via air inlet44under pressure gauge46corresponds with pressure gauge54. Similarly, the gate valve68in the termination cap14may be used to isolate the downstream portion of the termination cap14from the interior of the pipeline section200. In use, the gate valve68can be closed when introducing and removing components, such as the spin-cast delivery head, into the termination cap14. As with gate valve42, the downstream portion of the termination cap14can be subjected to a partial vacuum that corresponds with internal vacuum pressure before re-opening the gate valve68. For example, pressurized air may be introduced into the downstream portion via a second air/vacuum inlet71(shown in broken lines inFIG. 9) disposed in the downstream portion of the termination cap14until pressure gauge72corresponds with pressure gauge74. Further, the gate valve52in the UV foil inversion tube30may be used to close off the UV foil inversion tube30after the UV foil18has been inverted in the pipeline section200.

In some applications, it may be desired to inspect the interior208of the pipeline section200at different stages. For example, it may be desirable to pre-inspect the interior surface206of the pipeline section200to assess the potential for adequately applying the desired coating26. In such applications, the camera of the camera system24may be moved through the interior208from one end of the pipeline section200to the other. This step may be performed before or after the inlet adapter12and/or termination cap14have been installed. In one embodiment, the camera is inserted into the main tube28of the inlet adapter12. For example, the primary access cap38or the secondary access cap40may be removed and the camera may be inserted into the interior of the main tube28. In applications that involve a wired/corded connection between the camera and the display, the wires/cords may be fitted through the secondary access cap40, which include a grommet or other generally leaktight structure through which the wires/cords may pass into the interior of the main tube28. As noted above, the camera system24may be used to inspect the interior of the pipeline section200at essentially any time, such as prior to any other activity, after or during pipeline preconditioning, after or during coating, before curing, during curing, after curing and after removal of the UV foil18. When the inlet adapter12is installed, the camera may be introduced via the main tube28as discussed above. When the inlet adapter12is not installed, the camera may be introduced through the open upstream end202of the pipeline section200. The camera need not, however, be introduce through the upstream end at all times. For example, when the UV foil18is not in place, the camera may be introduced through the downstream end204. When termination cap14is in place, the camera may be introduced through the termination access cap66. When the termination cap14is not installed, the camera may be fed into the open downstream end204of the pipeline section.

In the illustrated embodiment, the method may include the optional step of preparing the pipeline section200for coating. This may involve, for example, cleaning and profiling the interior surface206of the pipeline section200. In this embodiment, the step may include the use of one or more preconditioning heads that are configured to travel through the interior208of the pipeline section200. The preconditioning head(s) may be moved manually or through automation along the interior of the pipeline section200. The coating system10may incorporate essentially any preconditioning equipment capable of providing the desired pipeline preconditioning. A variety of commercially available preconditioning equipment can be readily incorporated into the present invention. For example, the preconditioning head(s) may be one or more pipeline pigs configured to scape, brush or otherwise condition the interior surface of the pipe. If some applications, the preconditioning head(s) may have active elements that are driven to mechanically abrade or otherwise condition the interior surface of the pipeline. For example, the preconditioning head(s) may expel a high pressure fluid (e.g. air or water). The fluid may include an abrasive media, such as sand for sandblasting. As another example, the preconditioning head(s) may include a wire brush or other abrasive mechanical components that are spun or otherwise motivated to clean and/or profile the interior surface206. As noted above, the camera system24may be use to inspect the pipeline section200to determine the appropriate preconditioning apparatus and after preconditioning to ensure that the internal surface206is prepared to receive coating26.

As noted above, the present invention includes the step of applying the coating26to the interior surface206of the pipeline section200. In the illustrated embodiment, the coating26is applied by a coating delivery system16that is capable of moving through the interior of the pipeline section200. Although the coating delivery system16may vary from application to application, the coating delivery system16of the illustrated embodiment is a generally conventional spin-cast delivery system having a delivery head80that is movable through the interior of the pipeline section200. The delivery head80may be moved from the interior of the pipeline section200manually or through the use of automation, such as a powered trolley (not shown). In use, the delivery head80is introduced into the pipeline section200through the downstream end204. To prepare for coating, the delivery head80is moved through the interior of the pipeline section200to a position at or near the upstream end202. For example, the delivery head80may be moved to a point slightly downstream from the upstream end202. The delivery head80is then activated and the delivery head80is moved at a constant speed from the upstream end202to the downstream end204. The speed of movement of the delivery head80is selected so that an appropriate layer of the coating is applied uniformly over the interior surface206. In applications involving alternative coating systems, the coating delivery step may be varied as appropriate for the alternative coating system. The coating delivery head80may alternatively be introduced and operated from the upstream end of the pipeline section200. As noted above, the present invention may be used to apply a broad range of coatings. In the illustrated embodiment, the coating26is an epoxy material. To prepare the epoxy material for coating delivery, the component parts of the epoxy material may be mixed just prior to use in the coating delivery process. The use of a UV-curable epoxy will help to prevent the coating26from curing before it is applied, distributed and held in suspension by the UV foil18.

Following application of the coating26, the present invention may optionally include one or more steps intended to assist in providing a uniform coat of the desired thickness over the entire interior surface206. For example, the present invention may include the step of passing a pig or squeegee through the interior of the pipeline section200after the coating delivery step. A variety of commercially available pigs or squeegees are appropriate for use in distributing the applied coating26. In use, the pig or squeegee may be introduced into the pipeline section200from the downstream end204and moved through the complete length of the pipeline section200. In some application, a single pass may be appropriate and the pig or squeegee can be removed from the upstream end202of the pipeline200. In other applications, the pig or squeegee may be moved through the pipeline section200in both directions before removal. In some applications, it may be desirable to pass two or more pigs or squeegees through the interior of the pipeline section200in series.

As discussed above, the UV foil18is inverted into the interior of the pipeline section200and pressurized to assist in distributing and suspending the coating26in a uniform and continuous layer along the interior surface206. In the illustrated embodiment, the step of inverting the UV foil18into the pipeline section200includes the steps of: coupling the foil outlet88of the air inversion shooter82to the freed end of the UV foil inversion tube30, feeding the UV foil18through the air inversion shooter82and supplying pressure to the manifold portion86of the shooter. Pressure is supplied to the shooter82until the full length of the UV foil18is fed through the shooter82and the UV foil18is fully inverted along the pipeline section200. The UV foil18may be internally pressurized to the desired pressure by the shooter82. As discussed above, the UV foil18may be pressurized with sufficient pressure to assist in distributing and suspending the coating26uniformly over the interior surface26of the pipeline section200. In typical applications, the internal pressure of the UV foil18may be in the range of 3-10 psi, but the internal pressure may be outside this range in some applications. Once internally pressurized, the gate valve52can be closed to prevent pressurized air from escaping out the UV foil inversion tube30. At this point, the free end of the UV foil18is held around the upstream end202of the pipeline section200opening toward the main tube28of inlet adapter14. The pressure gauge54in the UV foil inversion tube30may be used to assist in bringing the interior of the UV foil18to the desired pressure. In some applications, the UV foil18may be elastic and may have a resting shape and size that is smaller (e.g. length and diameter) than the pipeline section200. In these applications, the introduction of internal pressure may cause the UV foil18to expand in a manner akin to a balloon to fill the interior space208and coming into firm contact with the interior surface206. In some applications, it may be desirable to visually inspect the interior of the pipeline section200using the camera system24before and/or after the UV foil18is inverted. Inspecting the pipeline before UV foil inversion may help to identify voids in the coating26that might be removed during UV foil18inversion. Inspecting the pipeline after UV foil inversion may help to identify defects into the coating application prior to the curing step while they can still be addressed.

In the illustrated embodiment, the method includes the step of applying a vacuum (e.g. partial vacuum) to the pipeline section200between the exterior of the UV foil18and the interior wall206. The primary goal of the vacuum is to remove air from between the UV foil18and the interior wall206to assist in eliminating voids in the coating26and uniformly distributing the coating26. Although the vacuum may be applied in essentially any suitable manner, the step is achieved in the illustrated embodiment by introducing a vacuum at the downstream end204of the pipeline section200. The vacuum may be introduced through the termination cap14positioned on the downstream end204. More specifically, a vacuum source may be coupled to air/vacuum inlet70. The vacuum source may be engaged during the UV foil18inversion step, which may help in inverting the UV foil18. Alternatively, it may not be engaged until after the UV foil18has been inverted and/or internally pressurized. The vacuum introduced to the system may vary from application to application depending in large part on the physical properties of the coating26. In the illustrated embodiment, the vacuum may be in the range of −5 to −10 inches Hg, but the vacuum may be outside this range in some applications. In some applications, the vacuum may vary over time. For example, the vacuum applied during the UV foil inversion step may vary from the vacuum applied following that step. The pressure gauges72and74may be used to achieve and maintain the desired vacuum through the desired portions of the coating method. In some applications, internal pressurization of the UV foil18may be sufficient to provide acceptable results. In such applications, this vacuum step may be eliminated.

Once the UV foil18has been inverted and properly pressurized (and any desired vacuum is drawn on the downstream end of the pipeline section200), the UV light source22may be moved through the interior208of the pipeline section200to cure the coating26. As noted above, the camera system24can be moved through the interior of the pipeline section200to allow the operator to visually inspect the coating26as it is held in suspension by the UV foil18. In some applications, it may be possible to eliminate any voids or other inconsistencies in the coating26by increasing the internal pressure or the external vacuum. The UV light source22is then moved through the interior of the pipeline section200. The speed of motion of the UV light source22is selected so that the coating26receives sufficient UV light to render the UV inhibitor non-functional, thereby allowing the coating26to rapidly cure. In the illustrated embodiment, the UV light source22is carried by a motorized trolley96. Motion of the trolley96may be automated so that the UV light source22travels at the appropriate speed along the full length of the interior of the pipeline section200.

Following curing, the method may include the step of removing the UV foil18form the interior of the pipeline section200. The UV foil18may be removed using a variety of alternative steps. However, in the illustrated embodiment, the UV foil18is removed by releasing the internal pressure on the UV foil18, for example, by opening the gate valve52in the UV foil inversion tube30and/or an access cap38or40(with gate valve42open) in the main tube28, and releasing any vacuum that may be applied to the downstream end, for example, by opening the access cap66in termination cap14with the gate valve68open. The inlet adapter12is removed to release the open end of the UV foil18after which the UV foil18can be removed from the pipeline section200through either the upstream end202or the downstream end204.