Method and apparatus for launching and recovering a remote inspection device from a volatile liquid storage tank

Methods and apparatus for launch and recovery of a remote inspection device within a liquid storage tank are described herein. In one embodiment, the tank is accessed by opening an entrance hatch and then injecting a vapor suppression foam across a surface of a stored liquid mass to form a foam layer. A launching system having a remote inspection device is attached to the entrance hatch to define a launch and recovery space sealed from an external environment and isolated from the stored liquid mass in the tank via a valve and the foam layer. The launch and recovery space is purged of hazardous vapors by injection of an inert gas prior to launch and recovery of the remote inspection device. Prior to removal of the launching system, the surface of the stored liquid mass is re-coated with vapor suppression foam.

BACKGROUND

Field

Embodiments of the present disclosure generally relate to methods and apparatus for inspection of liquid storage vessels, and more particularly, inspection of hydrocarbon storage tanks.

Description of the Related Art

Hydrocarbon-based fluids, such as crude oil and gasoline, are often stored in large hydrocarbon storage tanks built above ground. These storage tanks are typically cylindrical in shape and formed of steel. As a preventive measure against corrosion and the escape of stored product into the surrounding environment, the storage tanks are coated and connected to a sacrificial metal structure for cathodic protection. Despite these preventative measures, the storage tanks still remain vulnerable to the salts, acids, and other corrosive materials found in the crude oil and refined hydrocarbon-based products they are meant to hold. Thus, routine and periodic inspections of the interiors of the storage tanks are necessary to determine the integrity of such structures.

Though necessary, inspections of the storage tanks require a significant amount of time and effort in order to perform the inspections safely and thoroughly. Conventional inspections typically require taking the storage tank out of service, draining all the stored hydrocarbon products from the tank, and deploying a human inspector into the tank to conduct the inspection while additional support personnel and equipment are stationed nearby. Efforts have recently been made to utilize remote inspection devices to allow inspection of the storage tanks without draining the stored hydrocarbon products and deploying personnel therein. However, deployment of remote inspection devices remains problematic due to a lack of containment of hazardous vapors that are continuously volatilized from the stored hydrocarbon products. Current remote inspection systems either do not provide proper containment of the hazardous vapors during inspection, or utilize a tethering system for the remote inspection devices that causes sealing issues and potential contamination of the manway and its surroundings.

Accordingly, what is needed in the art are improved methods and apparatus for inspection of liquid storage vessels.

SUMMARY

The present disclosure generally relates to methods and apparatus for inspection of liquid storage vessels. In one embodiment, an apparatus for inspection of a liquid storage vessel is provided. The apparatus includes a chamber body having an internal volume partially defined by one or more sidewalls and a lid and a closure coupled to the chamber body opposite of the lid and further defining the internal volume. The apparatus further includes a gas injection port is disposed through the chamber body for delivering an inert gas into the internal volume and a lifting system within the internal volume for transporting an inspection device through the closure.

In one embodiment, a method for deploying an inspection device into a hazardous environment containing a mass of vaporizable liquid is provided. The method includes providing a launching system having a closed vessel with an inspection device disposed therein, forming a vapor suppression layer on the liquid mass at an access passage of a storage tank, and attaching the closed vessel of the launching system to the access passage. The method further includes inerting an internal volume of the closed vessel of the launching system, opening the closed vessel to the access passage, and passing the inspection device from the launching system into the liquid mass.

In one embodiment, a method inspecting a storage vessel is provided. The method includes injecting a vapor suppression foam into an opening of the storage vessel to form a vapor suppression layer over a liquid mass therein and coupling a launching system having an inspection device to the opening. A volume between the launching system and the vapor suppression layer is inerted by injecting one or more inert gases into the volume. A closure of the launching system is opened, and a cable removably coupled to the inspection device is unwound to lower the inspection device into the liquid mass. When the inspection device is in the storage vessel, the inspection device is uncoupled from the cable.

DETAILED DESCRIPTION

The present disclosure relates to methods and apparatus for launch and recovery of a remote inspection device within a liquid storage tank. In one embodiment, the tank is accessed by opening an entrance hatch and then injecting a vapor suppression foam across a surface of a stored liquid mass to form a foam layer. A launching system having a remote inspection device is attached to the entrance hatch to define a launch and recovery space sealed from an external environment and isolated from the stored liquid mass in the tank via a valve and the foam layer. The launch and recovery space is purged of hazardous vapors by injection of an inert gas prior to launch and recovery of the remote inspection device. Prior to removal of the launching system, the surface of the stored liquid mass is re-coated with vapor suppression foam.

FIG.1is a cross-sectional view of a launching system100for a remote inspection device150according to one embodiment. The launching system100includes a chamber body102having one or more sidewalls104and a lid106at least partially defining a launch and recovery volume110. In one embodiment, the lid106is integrally coupled to the sidewalls104. In one embodiment, the lid106is removably coupled to the sidewalls104. The chamber body102may have any suitable morphology and dimensions. In one embodiment, the chamber body102has a substantially cylindrical shape. In another embodiment, the chamber body102has a polygonal shape, such as a rectangular shape or the like. In some embodiments, the chamber body102is shaped to correspond with a morphology of an opening or manway in a liquid storage tank. The chamber body102is fabricated from a material suitable for maintaining a low pressure and inerted environment therein, such as metallic materials, for example aluminum and titanium. In another aspect, the chamber body102is fabricated from a metal alloy, for example stainless steel, carbon steel, hastelloy, and nickel alloy. Furthermore, the chamber body102and any equipment or components coupled thereto are electrically bonded to match the electric potentials thereof. For example, the chamber body102and the equipment or components coupled thereto may be electrically bonded via one or more bonding straps, bus bars, jumper wires, shunts, rods, adhesives, and other suitable electrical connectors.

The chamber body102further contains a winch140, a cable142, and a remote inspection device150therein. The winch140may be coupled to the chamber body102at any suitable location, such as for example, to the lid106or a distal end of the sidewalls104as depicted inFIG.1A. In one embodiment, the winch140is a manual hand winch having a handle144disposed external to the launch and recovery volume110for manual hand crank operation. In another embodiment, the winch140is a pneumatic winch to which compressed air may be fed in a location external to the launch and recovery volume110. In yet another embodiment, the winch140is a hydraulic winch. Rotation of the winch140enables winding and unwinding of the cable142, to which the remote inspection device150is removably coupled at a distal end thereof. Thus, the remote inspection device150may be raised and lowered through the chamber body102by rotation of the winch140when the launching system is in an upright position. In one embodiment, the cable142is fabricated from a material suitable to withstand a high tension generated by the weight of the remote inspection device150when coupled thereto, such as a load capacity between about 200 pounds and about 500 pounds. For example, the cable142is fabricated from a metallic material such as aluminum, titanium, or a metal alloy. In some examples, the cable142is fabricated from the same metallic material as the chamber body102.

The remote inspection device150includes any suitable submersible apparatus for inspection of liquid-containing vessels. For example, the remote inspection device150is a submersible vehicle configured to perform tethered or tetherless inspection of liquid-containing vessels. In one embodiment, the remote inspection device150is controlled by a user at a remote location. Additionally or alternatively, the remote inspection device150may have autonomous functionality. Generally, the remote inspection device150includes a chassis, a locomotion or propulsion system, a power source, and one or more sensors for performing inspection of liquid-containing vessels. Examples of sensors that may be integrated with the remote inspection device150to aid in inspection include an optical sensor, a magnetic field sensor, a phased-array ultrasonic testing system, a gyrocompass, an inertial navigation system, a speed sensor, an acoustic ranging system, and an acoustic or Doppler sensor. In one embodiment, the remote inspection device150includes a nose cone (not shown) having a substantially conical shape for centering the remote inspection device150upon entry into the launching system100during recovery thereof. For example, the nose cone may be utilized to guide and stabilize the remote inspection device150while the remote inspection device150is raised through a lower opening of the launching system100.

In one embodiment, one or more sets of device guides152are optionally disposed within the launch and recovery volume110upon which the remote inspection device150may be raised and lowered. In combination with the nose cone, the one or more sets of device guides152are utilized to position and usher the remote inspection device150during launch and recovery and prevent swinging thereof. For example, the one or more sets of device guides152may prevent collision of the remote inspection device150with the sidewall104while the remote inspection device150is being raised, lowered, or stored within the chamber body102. In one embodiment, the one or more sets of device guides152are rails, tracks, or slots disposed through the launch and recovery volume110.

A pressure relief port122, a test port124, an inert gas injection port126, and an optional wash port128are disposed through the one or more sidewalls104and/or the lid106. For example, the pressure relief port122, the test port124, the inert gas injection port126, and the wash port128may be disposed at a distal end of the sidewalls104. In one embodiment, the pressure relief port122includes a y-type valve, a k-type valve, a spring-loaded valve, or any other suitable type of automatic control valve. The pressure relief port122functions as a fail-safe to automatically release gases from the launch and recovery volume110when an internal pressure exceeds a desired or preset limit. The test port124provides a coupling for diagnostic equipment (not shown) to monitor one or more conditions of the launch and recovery volume110. In one embodiment, the test port124may serve as an adaptor for a pressure gauge, a temperature gauge, or the like. The gas injection port126facilitates the delivery of one or more gases into the launch and recovery volume110, for example, during the launch and recovery of the remote inspection device150. In one embodiment, the inert gas injection port126is coupled to a gas supply (not shown) configured to supply one or more inert gases into the launch and recovery volume110, such as nitrogen, argon, and the like. Altogether, the pressure relief port122, the test port124, and the gas injection port126are utilized to inert the launch and recovery volume110and maintain a slight overpressure of inert gas above ambient atmospheric pressure therein during launch and recovery of the remote inspection device150. In one embodiment, the pressure relief port122, the test port124, and the gas injection port126are disposed in close proximity to one another for easier accessibility to a user.

In some embodiments, the launching system100may include the optional wash port128. The wash port128facilitates the delivery of one or more cleaning fluids into the launch and recovery volume110. For example, the wash port128may be coupled to a cleaning fluid supply (not shown) configured to supply one or more cleaning fluids to the launch and recovery volume110to clean the remote inspection device150, cable142, and interior walls of the chamber body102. Suitable cleaning fluids for use with the launching system100include non-corrosive or biodegradable agents. In one embodiment, the wash port128is further coupled to an annular spray device129, such as a showerhead, disposed between the winch140and the remote inspection device150and around the cable142. For example, the spray device129may be coupled to the chamber sidewalls104or the lid106. The spray device129is utilized to direct and distribute the cleaning fluids within the interior of the chamber body102, such as against the cable142, the remote inspection device150, and the interior walls of the chamber body102.

One or more lifting lugs127are coupled to an exterior surface of the chamber body102, such as the sidewalls104or the lid106. Two lifting lugs127are shown coupled to the lid106inFIG.1A. The lifting lugs127provide anchor points for one or more cables of a lifting device (not shown) to attach thereto and hoist the launching system100onto or off of the liquid storage tank. For example, the launching system100may be lifted onto a roof of the storage tank via a crane or other suitable device having a hoisting cable attached to the lifting lugs127. In one embodiment, the lifting lugs127are formed of a material similar to that of the chamber body102, such as aluminum, titanium, or a metal alloy.

A closure108is coupled to the chamber body102at a flange105and further defines the launch and recovery volume110. The closure108enables opening and closing of the launch and recovery volume110to an external environment, such as the interior of the liquid storage tank. In some embodiments, the closure108is a ball valve, a plug valve, or the like. Similar to the chamber body102, the closure108is fabricated from a material suitable for maintaining a low pressure environment within the launch and recovery volume110, such as metallic materials like aluminum, titanium, stainless steel, and other metal alloys.

In one embodiment, the closure108is a knife gate valve or a slide gate valve having a frame107and a gate blade118. The frame107and the gate blade118are shaped to correspond with the shape of the chamber body102. For example, if the chamber body102is cylindrical, the frame107may be annular and the gate blade118substantially circular. In another example, if the chamber body102is rectangular, the frame107and the gate blade118may be substantially quadrate. In one embodiment, the frame108has one or more gate seats109through which the gate blade118is actuated. When in a closed position112, the gate blade118is configured to seal the launch and recovery volume110from an external environment, for example the interior of the liquid storage tank. In one embodiment, the closure108includes a gate blade actuator (not shown), such as an external hand-wheel threaded onto a screw attached to the gate blade118. When the hand-wheel is rotated, the screw is axially moved by the wheel, causing the gate blade118to be moved in a first or second direction.

The closure108is coupled to a tank adapter114on a side thereof opposite the chamber body102. The tank adapter114facilitates coupling of the launching system100to an opening of the liquid storage tank, such as a manway or hatchway of the liquid storage tank. The tank adapter114is fabricated from a material suitable for maintaining a low pressure environment therein, such as metallic materials like aluminum, titanium, stainless steel, and other metal alloys. In one embodiment, the tank adapter114adapts the dimensions of the chamber body102and/or closure108to dimensions and morphologies of the liquid storage tank opening. For example, the tank adapter114adapts the diameter of the chamber body102adjacent the closure108to a diameter of the liquid storage tank opening. In one embodiment, the tank adapter114has an inner diameter lesser than an inner diameter of the chamber body102and/or an inner diameter of the closure108to account for manways or hatchways having smaller dimensions. Furthermore, the tank adapter114may have a lower annular surface115wide enough to adapt the launching system100to liquid storage tank openings having both narrower and wider diameters or widths, such as openings ranging in diameter/width between about 18 inches and about 36 inches, such as between about 24 inches and about 30 inches.

In one embodiment, the tank adapter114has a bolt pattern that matches a bolt pattern of the liquid storage tank opening, enabling direct bolting of the launching system100to the liquid storage tank. In another embodiment, the tank adapter114is clamped to the opening of the liquid storage tank by an external clamping system or device, such as a quick-latch system (not shown). For example, the tank adapter114is clamped to the opening of the liquid storage tank by a pull-action latch or toggle clamp, such as a U-hook type clamp, a J-hook type clamp, or the like. The utilization of a quick-latch system enables quick and efficient coupling of the launching system100to the liquid storage tank opening. The lower annular surface115of the tank adapter114may further include one or more grooves117for placement of one or more seals therein (not shown), thus enabling the creation of a hermetic seal between the launching system100and the storage tank during coupling. For example, the lower annular surface115of the tank adapter114may include one or more annular grooves117therein configured to support one or more o-rings (not shown). The one or more seals may be formed any suitable sealing materials, including but not limited to FFKM, PTFE, PEEK. Additionally or alternatively to the grooves117, the tank adapter114may be configured to be coupled to a gasket disposed between the tank adapter114and an opening of the liquid storage tank during operation of the launching system100.

The tank adapter114includes one or more release ports132and one or more injection ports134. The release ports132may include a vent port, a test port, a pressure relief port, and/or the like. In one embodiment, one or more gauges, such as a temperature gauge and a pressure gauge, may be coupled to the release ports132. In one embodiment, the one or more release ports132include a pressure relief port substantially similar to the pressure relief port122described above. The injection ports134may include a foam injection port, an inert gas injection port, and/or the like. In one embodiment, the one or more injection ports134include an inert gas injection port substantially similar to the inert gas injection port126. Altogether, the release ports132and the injection ports134may be utilized to assess, monitor, and control the conditions of a storage tank vapor gap (e.g. intermediate volume478inFIG.4D) prior to opening of the closure108and launch or recovery of the remote inspection device150.

FIG.2is a cross-sectional view of a launching system200configured to launch and recover the remote inspection device150according to one embodiment. The launching system200is substantially similar to the launching system100and includes all the features described with reference toFIG.1, but further includes a transport system260coupled thereto. Accordingly, only the transport system260will be described with reference toFIG.2.

The transport system260is configured to facilitate both vertical and horizontal transport of the launching system200along a roof of the liquid storage tank, thus enabling quick and efficient coupling of the launching system200to the opening of the liquid storage tank for engagement therewith. In one embodiment, the transport system260is removably (or fixedly) coupled to the chamber body102of the launching system200at an end thereof adjacent to the closure108and tank adapter114. The transport system260may include three or more wheel assemblies262and wheel mounts264to facilitate horizontal movement thereof. In such examples, the wheel mounts264may be directly or indirectly coupled to the chamber body102. In one embodiment, the transport system260includes a transport frame266for coupling the wheel mounts264to the chamber body102. For example, the transport frame266may include an annular frame coupled to and substantially surrounding a circumference of the chamber body102. In one embodiment, the wheel mounts264are attached to the transport frame266using pivoting arms and ball joints (not shown), thereby providing more freedom for placement of the wheel assemblies262relative to the transport frame266in case of obstructions around the opening of the liquid storage tank, such as rolling ladders.

The wheel assemblies262may generally include a wheel, a wheel frame, and a brake. For example, in one embodiment, the wheel assemblies262include a caster, such as a swivel caster or a ball caster. In such embodiments, the wheel assemblies262facilitate 360° directional horizontal movement of the launching system200. The wheel assemblies262, the wheel mounts264, and the transport frame266are fabricated from any suitable materials capable of withstanding a load capacity of the launching system200and the remote inspection device150. For example, the wheel mounts264and the transport frame266are fabricated from metallic materials such as aluminum, titanium, stainless steel, and other metallic alloys. In one embodiment, the wheels are pneumatic or foam-filled wheels configured to withstand the load capacities described above, in addition to shock loads from impacts caused by uneven surfaces of the liquid storage tank. Accordingly, the wheels may absorb the impact shock and cushion the launching system200during transport thereof.

The transport system260further includes a vertical actuator to facilitate vertical movement of the launching system200, thus enabling lowering and/or raising of the launching system200to/from the opening of the liquid storage tank. In one embodiment, the vertical actuator is a mechanical actuator, a hydraulic actuator, a pneumatic actuator, or the like. For example, the vertical actuator may be a mechanical actuator configured to convert rotary motion of a hand-wheel or handle into linear vertical displacement of the launching system200, such as a jack screw, a house jack, or the like.

FIG.3illustrates a flow diagram of a representative method300of launching a remote inspection device, such as the remote inspection device150, with the launching systems100,200ofFIG.1andFIG.2.FIGS.4A-4Hillustrate schematic, cross-sectional views of the launching system100at different stages of the method300. Thus, reference toFIGS.4A-4Hwill be included in the discussion ofFIG.3and the method300where warranted. AlthoughFIGS.4A-4Hdepict the launching system100, it should be understood that the method300may be performed utilizing the launching system200as well.

The method300for launching the remote inspection device150has multiple operations. The operations can be carried out in any suitable order or simultaneously (except where the context excludes the possibility), and the method can include one or more other operations which are carried out before any of the defined operations, between two of the defined operations, or after all of the defined operations (except where the context excludes the possibility). Not all embodiments include all the operations described.

In general, the method300includes controlling the volatilization of a stored liquid mass in a liquid storage tank by injecting a layer of vapor suppressing foam thereon at operation310. At operation320, an inerted launching system, such as the launching system100, is coupled to and sealed against an opening of the liquid storage tank. An inert gas is then supplied to a space above the liquid mass in the liquid storage tank at operation330. At operation340, a valve integrated with the launching system, such as the closure108, is opened, thus exposing an internal volume of the launching system to the vapor space. At operation350, a remote inspection device disposed within the launching system, such as the remote inspection device150, is transferred into the liquid storage tank via a winch and cable. Upon reaching a bottom surface of the liquid storage tank, the remote inspection device detaches itself from the cable at operation360. At operation370, the cable is rewound into the launching system and the closure is closed.

In one embodiment, the method300begins with operation310, corresponding toFIGS.4A and4B. At operation310, a cover plate462is removed from an opening464of a liquid storage tank400containing a liquid mass466. The liquid storage tank400may be any suitable type of storage tank for the storage of liquids, including but not limited to fixed roof tanks, external floating roof tanks, internal floating roof tanks, spherical tanks, bullet tanks, and the like. Examples of liquids466stored in the liquid storage tank400may include crude oil, gasoline, naphtha, diesel, kerosene, fuel oil, other petroleum combustibles and distillates, and the like. The opening464may be any suitable opening in the liquid storage tank400, such as a manway, manhole, or other type of opening.

After removal of the cover plate462, vapors accumulated in a vapor space468of the liquid storage tank400are released into an external environment482. Thus, a vapor suppression foam470may be immediately injected through the opening464to form a layer of the vapor suppression foam470atop the liquid mass466. By completely covering the liquid mass466with the layer of vapor suppression foam470, any further volatilization and release of vapors from the liquid mass466into the external environment is suppressed or prevented.

In one embodiment, the vapor suppression foam470is a firefighting foam, such as a class B foam designed to contain explosive vapors produced by flammable liquids. In one example, the vapor suppression foam470is a synthetic foam, such as an aqueous film forming foam (AFFF) or an alcohol-resistant aqueous film-forming foam (AR-AFFF). In another example, the vapor suppression foam470is a protein based foam, such as a regular protein foam (P), a fluoroprotein foam (FP), a film-forming fluoroprotein foam (FFFP), an alcohol-resistant fluoroprotein foam (AR-FP), or an alcohol-resistant film-forming fluoroprotein foam (AR-FFFP). The vapor suppression foam470is injected into the vapor space468via a foam delivery system472. In one embodiment, the foam delivery system472is a handheld compressed air foam system.

At operation320, the launching system100is coupled to the liquid storage tank400, depicted inFIGS.4C and4D. The coupling of the launching system100and the opening464forms an intermediate volume478between the layer of vapor suppression foam470or liquid mass466and the closure108. In one embodiment, the launching system100is lowered onto the opening464by a crane or other suitable lifting device (not shown) attached to one or more lifting lugs coupled to the chamber body102. In an alternative embodiment, the launching system100is lowered onto the opening464by adjusting the vertical actuator of the transport system260to a desired height after the launching system100has already been hoisted unto a roof of the liquid storage tank400and transported thereacross to the opening464.

Once the launching system100is aligned with the opening464, the tank adapter114is bolted or clamped to a flange465of the opening464using a latching mechanism469. In one embodiment, a gasket467is installed on the flange465prior to coupling with the tank adapter114, thus enabling a hermetic seal between the opening464and the launching system100. The gasket467may be formed of any suitable sealing materials, including but not limited to FFKM, PTFE, PEEK. Alternatively, the lower annular surface115of the tank adapter114may include grooves117already having one or more seals disposed therein, such as o-rings, thus eliminating the need for utilizing the gasket467.

At operation330, the launch and recovery volume110and the intermediate volume478are purged and inerted by removing and displacing gases therein with an inert gas. For example, the initially-present gases may be displaced by an inert gas such as nitrogen, argon, and the like. In one embodiment, the inert gas is injected into the launch and recovery volume110through the inert gas injection port126, while the initially-present gas species of the launch and recovery volume110are purged through the pressure relief port122. Similarly, the inert gas is injected into the intermediate volume478through the one or more injection ports134, while the initially-present gas species of the intermediate volume478are removed through the one or more release ports132. An active, slight over-pressurization is then maintained in both the intermediate volume478and the launch and recovery volume110, such as a pressure less than 1 psi.

At operation340, the closure108is opened, thus desegregating the launch and recovery volume110and the intermediate volume478and forming a combined inert volume480between the launching system100and the liquid mass466, as depicted inFIG.4E. Desegregation of the launch and recovery volume110and the intermediate volume478equalizes the physical conditions, such as temperature and pressure, therebetween. In one embodiment, the closure108is opened by manually sliding the gate blade118out from the one or more gate seats109. In another embodiment, the gate blade118is actuated by operating a gate blade actuator, such as by rotating a hand-wheel.

After opening the closure108, the remote inspection device150is transferred into the liquid storage tank400at operation350, depicted inFIG.4F. In one embodiment, the remote inspection device150is lowered through the combined inert volume480and into the liquid mass466by rotating the handle144of the winch140and unwinding the cable142. In another embodiment, the winch140is operated via an electronic controller to wind and unwind the cable142, thus raising and lowering the remote inspection device150through the combined inert volume480. In some embodiments, the remote inspection device150is moved along one or more sets of guides152as it is transferred through the combined inert volume480. The one or more sets of device guides152help stabilize the remote inspection device150as it is raised and lowered through the chamber body102, preventing swinging thereof and collisions of the remote inspection device150against the sidewalls104. Within the liquid mass466, a negative buoyancy of the remote inspection device150enables it to sink to a storage tank floor401under its own weight as the cable142is unwound.

In one embodiment, the remote inspection device150automatically powers on as it is lowered into the liquid storage tank400. For example, the remote inspection device150is automatically activated and/or inactivated as it reaches a desired preset depth in the liquid mass466during launch and recovery. In such an embodiment, the remote inspection device150includes one or more mechanical pressure switches integrated into a power interlock system (not shown) therein. The utilization of the mechanical pressure switches enables the activation and/or inactivation of the remote inspection device150without application of power, thus preventing ignitions. Further, the mechanical pressure switches ensure that the remote inspection device150is only powered on when submerged a desired depth below the surface of the liquid mass466, thus facilitating activation of the remote inspection device150in an environment having a reduced oxygen content.

At operation360and depicted inFIG.4G, the remote inspection device150detaches from the cable142upon reaching the storage tank floor401. The remote inspection device150may then proceed with inspection of the liquid storage tank400as the cable142is reeled back into the chamber body102. At operation370and depicted inFIG.4H, the closure108is closed after the cable142has been reeled back in the chamber body102.

FIG.5illustrates a flow diagram of a representative method500of recovering a remote inspection device, such as the remote inspection device150, with the launching systems100,200ofFIG.1andFIG.2.FIGS.6A-6Hillustrate schematic, cross-sectional views of the launching system100at different stages of the method500. Thus, reference toFIGS.6A-6Hwill be included in the discussion ofFIG.5and the method500where warranted. AlthoughFIGS.6A-6Hdepict the launching system100, it should be understood that the method500may be performed utilizing the launching system200as well.

Similar to the method300, the method500for recovery of the remote inspection device150has multiple operations. The operations can be carried out in any suitable order or simultaneously (except where the context excludes the possibility), and the method can include one or more other operations which are carried out before any of the defined operations, between two of the defined operations, or after all of the defined operations (except where the context excludes the possibility). Not all embodiments include all the operations described.

In general, the method500includes opening the closure of the launching system at operation510and lowering the cable into the liquid storage tank at operation520. At operation530, the remote inspection device already deployed in the liquid storage tank latches onto the cable at the liquid storage tank floor. The remote inspection device is then hoisted through the liquid storage tank and into the launching system at operation540. At operations550and560, the closure is closed, the internal volume of the launching system is re-inerted, and the liquid mass within the liquid storage tank is re-coated with the vapor suppression foam. The launching system is then removed from the liquid storage tank at operation570and the liquid storage tank is sealed at operation580.

In one embodiment, the method500begins with operation510, corresponding toFIG.6A. At operation510, the closure108is opened, thus once again combining the launch and recovery volume110and the intermediate volume478to form the combined inert volume480, depicted inFIG.6B. Opening of the closure108equalizes the physical conditions between the launch and recovery volume110and the intermediate volume478, such as temperature and pressure. Similar to embodiments described above, the closure108may be opened by manually sliding the gate blade118out from the one or more gate seats109. In another embodiment, the gate blade118may be actuated by operating a gate blade actuator, such as a hand-wheel.

Optionally, prior to opening of the closure108, the launch and recovery volume110and/or the intermediate volume478may be re-inerted. For example, the launch and recovery volume110and the intermediate volume478are purged and re-inerted by removing and displacing gases therein with an inert gas. In one embodiment, the inert gas is injected into the launch and recovery volume110through the inert gas injection port126, while the previously present gas species of the launch and recovery volume110are purged through the pressure relief port122. Similarly, the inert gas is injected into the intermediate volume478through the one or more injection ports134, while the previously present gas species of the intermediate volume478are removed through the one or more release ports132.

As depicted inFIG.6B, after opening of the closure108, the cable142is unwound from the winch140at operation520and lowered into the liquid storage tank400until an end of the cable142reaches the storage tank floor401. In one embodiment, the cable142is unwound by manually rotating the handle144of the winch140. In another embodiment, the cable is unwound by operation of a pneumatic or hydraulic controller coupled to the winch140.

At operation530and correspondingFIG.6C, the remote inspection device150locates the cable142at the storage tank floor40and attaches itself thereto. After attachment of the remote inspection device150to the cable142, the remote inspection device150is hoisted through the liquid storage tank400and into the chamber body102of the launching system100at operation540, as depicted inFIG.6D. As described above, the remote inspection device150is hoisted through the liquid storage tank400and the chamber body102by winding of the cable142. At a desired preset depth of the liquid mass466, the remote inspection device150may automatically power off by operation of one or more mechanical pressure switches integrated therein. Upon exiting the liquid storage tank400and entering the chamber body102, the remote inspection device150may be coupled to the one or more sets of device guides152to position and usher the remote inspection device150to a final storage position within the launching system100. For example, the remote inspection device150may be guided along one or more sets of tracks longitudinally disposed within the chamber body102as it is hoisted through the combined inert volume480.

Optionally at operation540, prior to closing the closure108at operation550, one or more cleaning fluids may be supplied to the launch and recovery volume110by the wash port128. For example, the wash port128and the spray device129may be utilized to wash the remote inspection device150, the cable142, the interior walls of the chamber body102, and other components or equipment within the launch and recovery volume110. In one embodiment, the cleaning fluids may be supplied to the launch and recovery volume110as the remote inspection device150is raised therethrough, thus washing the cable142and the remote inspection device150as it is recovered from the liquid mass466. In another embodiment, the cleaning fluids are supplied to the launch and recovery volume110after the remote inspection device150has been recovered and is secured within the launching system100.

At operation550and depicted inFIG.6E, the closure108is closed. As described above, the closure108may be closed by manually sliding the gate blade118into the one or more gate seats109of the frame107. In another embodiment, the gate blade118may be actuated by operating a gate blade actuator, such as a hand-wheel. Closing of the closure108results in the reformation of the launch and recovery volume110within which the remote inspection device150is stored. At this point, the launch and recovery volume110is re-inerted, as described above with reference to operations330and510.

Upon removal of the remote inspection device150from the liquid mass466, the vapor suppression foam470may be re-injected into the opening464at operation560to reform the layer of vapor suppression foam470atop the liquid mass466. Thus, any further volatilization and release of vapors form the liquid mass466is suppressed prior to removal of the launching system100from the opening464. In one embodiment, the vapor suppression foam470is injected into the opening464through a foam injection port134disposed through the tank adapter114.

At operation570and correspondingFIG.6G, the launching system100is uncoupled and removed from the opening464of the liquid storage tank400. The launching system100is uncoupled from the opening464by removing or releasing a latching mechanism469connecting the tank adapter114to the flange465. In one embodiment, the latching mechanism469includes one or more bolts disposed through the tank adapter114and the flange465. In another embodiment, the latching mechanism469includes a clamp connecting the tank adapter114and the flange465. Upon removal or release of the latching mechanism469, the launching system100is removed from the opening464. In one embodiment, the launching system100is raised from the opening464by a crane or other suitable lifting device (not shown) attached to one or more lifting lugs thereof. In an alternative embodiment, the launching system100is raised away from the opening464by adjusting the transport system260to a desired height. As depicted inFIG.6H, once the launching system100is removed from the opening464, the cover plate462is resealed against the opening464at operation580.

It is contemplated that one or more aspects disclosed herein may be utilized to deploy a remote inspection device within a liquid storage tank, such as a hydrocarbon storage tank, containing a hazardous environment therein. The application of the above-described aspects enables thorough inspection of hydrocarbon storage tanks in a safe and efficient manner while liquid product is stored therein. In one aspect, hazardous vapors within a hydrocarbon storage tank are contained within the tank by utilization of a vapor suppression foam and an inerted remote inspection device launching system. The utilization of the vapor suppression foam and the inerted launching system prevents the escape of volatile and hazardous vapors from releasing into the surrounding environment during storage tank inspection. In further aspects, the remote inspection device launched into the storage tank is configured to activate in an environment with low oxygen content and without the application of external power, thus preventing ignition. Accordingly, the aspects described herein prevent the exposure of nearby personnel to hazards normally associated with hydrocarbon storage facilities.

Although the systems and processes described herein have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the disclosure as defined by the following claims. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the claimed subject matter that are not exactly as described herein. It is the intent of the inventors that variations and equivalents of the disclosure are within the scope of the claimed subject matter while the descriptions, abstract, and drawings are not used to limit the scope of the claimed subject matter.