Patent Application
20120096702
The present invention relates to an automated system for constructing a relatively tall structure by lowering all or part of the structure below ground level rather than using scaffolding to support work and equipment relatively high above ground level. Stable ground level work stations facilitate automation using robots for assembly.
Constructing relatively tall structures typically involves working at substantial heights above ground. Examples of relatively tall structures include vessels such as, but not limited to, oil storage tanks and oil production tanks. Assembly of scaffolding both inside and outside a storage tank during construction or maintenance is thus typically required to support workers and equipment. Workers ascending, descending, and working at elevation are at increased risk of injury from falling, and repeatedly ascending and descending scaffolding in order to get to and from work takes valuable time and energy.
Lifting equipment onto scaffolding is also time and energy consuming. Construction of large tanks may require multiple cranes or other lifts for raising equipment and supplies onto scaffolding, in addition to larger cranes or lifts used to raise upper level tank components into place for tank assembly. Tools and equipment installed on or supported by scaffolding may have size limitations imposed due to space or weight limitations of the scaffolding.
In addition, precise placement of tools and equipment used in tank assembly may be limited by imprecision in scaffolding positioning and scaffolding positional instability. This imprecision may be particularly problematic for automated processes such as robotic welding, cutting, or testing, where positional parameters must be highly precise.
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings. The drawings are for illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:
Embodiments of the present invention comprise an automated construction system that includes an inner work station and an outer work station, with the outer work station typically surrounding the inner work station. The outer work station resides at about ground level, with a shaft extending downwardly from an area residing between the inner work station and the outer work station. Embodiments of the automated construction system further comprise a hoist adapted to raising and lowering a work piece in the shaft. Some embodiments comprise a rotating device adapted to rotate the work piece, and in some embodiments the hoist and rotating device are one and the same. Embodiments of the present invention further comprise a carousel adapted to forming work piece sections from metal plate. The work piece may be a relatively tall vessel or part thereof. An example of a relatively tall vessel includes, but is not limited to, an oil storage tank or an oil production tank. A completed 1000 bbl oil storage tank is typically about 32 feet tall. A relatively tall vessel is typically greater than twelve feet tall.
The terms and phrases as indicated in quotation marks (“ ”) in this section are intended to have the meaning ascribed to them in this Terminology section applied to them throughout this document, including in the claims, unless clearly indicated otherwise in context. Further, as applicable, the stated definitions are to apply, regardless of the word or phrase's case, to the singular and plural variations of the defined word or phrase.
The term “or” as used in this specification and the appended claims is not meant to be exclusive; rather the term is inclusive, meaning “either or both.”
References in the specification to “one embodiment”, “an embodiment”, “another embodiment, “a preferred embodiment”, “an alternative embodiment”, “one variation”, “a variation” and similar phrases mean that a particular feature, structure, or characteristic described in connection with the embodiment or variation, is included in at least an embodiment or variation of the invention. The phrase “in one embodiment”, “in one variation” or similar phrases, as used in various places in the specification, are not necessarily meant to refer to the same embodiment or the same variation.
The term “couple” or “coupled” as used in this specification and appended claims refers to an indirect or direct connection between the identified elements, components, or objects. Often the manner of the coupling will be related specifically to the manner in which the two coupled elements interact.
The term “approximately,” as used in this specification and appended claims, refers to plus or minus 10% of the value given.
The term “about,” as used in this specification and appended claims, refers to plus or minus 20% of the value given.
The terms “lift and rotate table,” “lifting rotating table,” and “LRT,” as used in this specification and appended claims, refer to a platform or support adapted to raise and lower with a work piece supported thereupon, and to permit the work piece to rotate while being supported by the platform or support, while the work piece is disposed in or partially in an automated construction system shaft. Thus a hoist in an automated construction system shown in
The term “MIG-P,” as used in this specification and appended claims, refers to pulsed metal inert gas welds or welding.
The terms “manufacturing” and “fabrication,” are used interchangeably in this specification and appended claims, and refer to construction or assembly of a structure or component thereof.
The term “ground level,” as used in this specification and appended claims, refers to a level or altitude of a surface of the ground. Accordingly, an object or space that is below ground level resides at a level or altitude below a surface of the ground immediately proximate the object or space. An object or space that is above ground level resides at a level or altitude above a surface of the ground immediately proximate the object or space. An object or space that is considered at ground level, for purposes of this specification and appended claims, resides at a level or altitude about even with or slightly above or below a surface of the ground immediately proximate the object or space; an object that resides at ground level may rest on a surface of the ground.
The term “continuous sidewall structure,” as used in this specification and appended claims, refers to a structures having sidewalls, the bases of which form closed figures. For example, a cylindrical structure is a continuous sidewall structure because its base forms a circle, which is a closed curve. Other continuous sidewall structures include structures having sidewalls and whose bases form closed figures such as, but not limited to, circles, ovals, and other closed curves, and regular and irregular polygons. A structure may have an aperture in its sidewall and still be a continuous sidewall structure.
The term “ellipse,” as used in this specification and appended claims, refers to a plane curve such that the sums of the distances of each point in its periphery from two fixed points, the foci, are equal. It is a conic section formed by the intersection of a right circular cone by a plane that cuts the axis and the surface of the cone. Circles and ovals are special types of ellipses.
The term “closed curve shape,” or “closed figure shape,” as used in this specification and appended claims in reference to structures formed by metal plate, refers to a three dimensional analogue of a two dimensional closed curve or closed figure. For example, where metal plate is bent to form a closed curve shape that is a circle, the metal plate forms an open ended cylindrical structure. Where metal plate is bent to form a closed figure shape that is a rectangle, the metal plate forms an open ended right rectangular parallelepiped structure. In other words, the closed curve shape or closed figure shape is a three dimensional shape having a base that is a closed curve or closed figure, respectively.
An embodiment of an automated construction system 10 is illustrated in
While outer work station 16 is shown with only one outer working level 22, more than one outer working level may be included in some embodiments. Additional outer working levels allow multiple sections 24 of work piece 20 to be worked on at a time, or to access sections not currently being worked on. In addition, inner work station 12 may be removable to allow work to be done on other types of work pieces 20, where inner work station 12 would be inappropriate. Work piece 20 may be any structure with a continuous sidewall. The continuous sidewall may be cylindrical, oblong, oval, square, rectangular, or the like. A cylindrical work piece 20 is shown in the accompanying drawings, and discussed below as an example only. Those of ordinary skill in the art will be aware that modifications may be made to accommodate structures that are other than cylindrical.
Referring to
Referring to
While bearings have been illustrated as a rolling mechanism, there are many possible means for rotating work piece 20, such as bushings, rollers, or the like. In some embodiments, work piece 20 may be made rotatable in other ways. For example, by providing bearings in hoist 26 itself between two overlapping horizontal sections, or between two abutting horizontal sections. Referring to
As mentioned above, automated construction system 10 is designed to accommodate different sizes and shapes of work pieces 20. Referring to
Work piece 20 may be fabricated using preformed sections 24, where the vertical seam has been previously welded. Referring to
In some embodiments, metal plate may be fed continuously at a feed angle that is greater than 90°, the feed angle being an angle at which the metal plate intersects an axis of cylinder of a nascent work piece. A feed angle greater than 90° could abrogate a need for vertical seams, the metal plate forming a continuous spiral.
In addition to embodiments described above, other variations may also be practiced. As illustrated in
The first carousel further comprises a plurality of radial forming assemblies 69 oriented in an array adapted to form or maintain metal plate 48 into a cylindrical shape having an axis of cylinder disposed approximately at the center post 58. Each of the plurality of radial forming assemblies 69 is about a same distance from the center post 58 as others of the plurality of radial forming assemblies. The radial forming assemblies 69 comprise guide rollers, indicated generally by 62, which are positioned about center post 58, and assist in forming or maintaining a generally cylindrical shape as the section is formed from the metal plate 48. Guide rollers 62 include inner rollers 64 for guiding a nascent section inside surface, bottom rollers 66 to support metal plate 48 along a bottom edge, and a vertical roller 68 to guide the nascent section outside surface. The radial forming assemblies 69 further comprise pivoting arms 70, on which the guide rollers 62 are mounted. The pivoting arms 70 are adapted to move outwardly away from a center of the first carousel 82 to form a section having a larger diameter. Conversely, the pivoting arms 70 are adapted to move inwardly toward the center of the first carousel 82 to form a section having a smaller diameter.
The pivoting arms 70 are coupled to a support post 72 and a roller 74. The pivoting arms 70 are biased inwardly by a spring, such that vertical roller 68 applies a force on the metal plate 48 along the nascent section outside surface to help form or maintain a curved shape, while still allowing arms 70 to move outwardly if sufficient force is applied. The nascent section outside surface is an outside surface of metal plate 48 that is formed into a cylindrical structure or other continuous sidewall structure, or is being formed into a cylindrical structure or other continuous sidewall structure.
Once metal plate 48 has been sufficiently played out by feed rollers 52, the leading edge of metal plate 48 is transferred from clamps 54 on rotating arm 56 to a first welding clamp 75 mounted on a first clamp support arm 76, and the trailing edge of metal plate 48 is clamped to a second welding clamp 78 mounted on a second clamp support arm 80. Clamp support arms 76 and 80 are then brought together, and a vertical weld is applied to join the leading and trailing edges of metal plate 48 to form metal plate 48 into a cylindrical section 24 that may then be moved using a crane to be attached to work piece 20, as shown in
A feed fence 83 is illustrated in
Second carousel 182 is illustrated in greater detail in
Where the actuator arm pushes the carriage 190 so that the carriage rollers 177 move inwardly toward a center of the carousel 182, the carriage rollers are positioned to bend or guide metal plate 148 into a curve having a shorter radius. Conversely, where the carriage rollers move outwardly away from a center of the carousel 182, the carriage rollers 173 are positioned to bend or guide metal plate 148 into a curve having a longer radius. Accordingly, the second carousel 182 is adapted to form metal plate into closed loops of various sizes, including cylindrically shaped sections having various diameters. In order to bend or guide metal plate along a curve, carriage rollers 177 apply a force on the metal plate 148 along a nascent section outside surface to help form or maintain a generally cylindrical shape. The force applied by the carriage rollers 177 is generated by the action of the actuator arms pushing against the support post 172 and the carriages 190.
Referring to
Referring to
As illustrated in
As illustrated in
Referring to
The automated construction system may also be used in situations other than tank fabrication. For example, existing tanks may be modified, repaired or retrofitted using similar design. In this situation, work piece 20 would be an existing vessel. For example, damaged sections to an existing vessel such as a used oil storage tank may be replaced including floors, roofs, or intermediate sections or sections may be removed or added to change the size of work piece 20. Other operations may also be performed, such as stripping insulation, in addition to welding and grinding operations. In one example, referring to
Once the insulation has been stripped, referring to
Referring to
It is anticipated that shaft 25 may be used to form other types of vessels. For example, referring to
Referring to
A first method of fabricating a cylindrical structure using the automated construction system described above with reference to
A second method of using an automated construction system is illustrated by a flow chart in
The second operation 502 comprises lowering the LRT on which the used oil tank resides, into the shaft, until a lower part of the used oil tank resides below ground level in the shaft, the lower part having a height of about 24 feet. An upper part of the used oil tank resides above ground level and has a height of about eight feet. In this position, the upper part is readily accessible to workers and equipment disposed on the outer work station, without requiring scaffolding. As illustrated in
The third operation 503 comprises rotating the used oil tank on the LRT and treating the oil tank while the lower part of the oil tank resides in the shaft. Treatment includes, but is not limited to, welding, cutting, removing corrosion, removing insulation, surface preparation, application of paint or other coating, application of anti-corrosive material, installation of insulation, and retrofitting the used oil tank. Treating the used oil tank may involve treating a tank exterior or tank interior.
The fourth operation 504 comprises elevating the oil tank completely out of the shaft. If retrofitting or rehabilitation is complete, the oil tank may be returned to service.
Some methods of using an automated construction system comprise fabrication of a vessel, the vessel being a cylindrical oil storage tank. The automated construction system comprises six-axis industrial robots interfaced to pulsed metal inert gas (MIG-P) welding sources, and to PLASMA cutting sources, manual welders, laborers, and a lift and rotate table (LRT). The vessel is a 1000 bbl oil storage tank. Fabrication is interactively performed with the help of the LRT, robots, and manual labor. Use of the LRT allows most operations to be performed safely at ground level or below. This feature significantly reduces risk of industrial accidents inherent in traditional assembly methods such as using scaffolding to support workers and equipment high above ground. The vessel fabrication using the LRT also results in faster manufacturing of oil storage tanks compared to existing manufacturing methods.
The vessel typically comprises four stacked sections, each section including a cylindrical outer wall, and all sections having a diameter approximately the same. The vessel typically further comprises a floor, a roof, and accessories mounted to or through its outer wall and roof. The vessel may also comprise paint, external insulation, or an internal coating such as epoxy.
The LRT is prepared for the assembly process by elevating the LRT to ground level and installing appropriate safety floor sections to avoid injuries to personnel caused by falling between inner and outer work stations and into a shaft that extends below the work stations. An appropriate build sequence (Programmable Logic Controller (PLC) program and robot programs), as well as the vessel dimensional data, are loaded to the system's controller. The vessel dimensional data may be loaded into the system controller from a conventional CAD file.
Vessel fabrication methods using embodiments of the automated construction system enable industrial automation to be combined with manual operations in construction of continuous sidewall structures such as oil storage tanks. The LRT works together with industrial robots and manual welders to facilitate welds and cuts throughout vessel fabrication. The system controller prompts and guides workers throughout the vessel build sequence. The system controller touch screen advises workers of all manual tasks to be performed on the vessel, displays any pertinent data required for them to execute their tasks, as well as requests the launch of automated assembly sequences. Vessel fabrication methods using embodiments of the automated construction system reduce chances of errors during vessel assembly, thus significantly increasing work quality as well as substantially decreasing cycle times and thus increasing manufacturing output capacity.
One embodiment of an automated construction system illustrated in
Embodiments of an automated construction system comprise remote control devices equipped with safety interlocking controls, interactive touch screens, and manual motion control of LRT functions. The remote control devices assist operators during manual tasks, display process information and vessel data, assist maintenance workers during their task, and simplify programming tasks.
Some embodiments of an automated construction system comprise two distinct zones identified and guarded appropriately for worker safety. A first zone is strictly forbidden to all operators' helpers, and welders; it is an area in which the industrial robots perform their work. The first zone may be accessed only by authorized personnel such as maintenance workers, programmers, and engineers under stringent safety procedures. A second zone is an area utilized for manual operations pertinent to assembly of a vessel. This second zone is a controlled safety zone; workers are permitted access only under certain circumstances such as when the robots are inactive or when operation of the robots does not create substantial danger or risk of injury to the worker. The second zone is controlled with approved safety devices such as, but not limited to, pressure sensitive safety mats, light curtains, multiple light beams, and/or proximity laser scanners. Access to the second zone is monitored by safety devices and in conjunction with the system controller.
INSTALLATION OF A FIRST SECTION—A first operation of vessel fabrication comprises forming a first cylindrical section. The first cylindrical section is formed using a carousel as illustrated in
Other vessel sections are formed in a substantially similar way as the first section. Once the first cylindrical section is formed, it is picked up by an overhead crane with an internal grip (or any other adapted handling device) to the top of the section and positioned onto a work piece holders disposed on an LRT. At this time, an operator informs the LRT controller via one of the remote control devices that the first section is in place, which actuates a series of internal positioning roller arms. The internal roller arms apply force outwardly to the internal wall of two superposed sections. These positioning devices are comprised of two sets of individually pneumatic actuated cylinders with rollers able to apply horizontal force to the inner wall of two vessel sections mounted one on top of each other without restricting the sections from being rotated by the LRT for the welding of their joint seam. They are automatically controlled via the LRT's system controller, and are used to maintain cylindrical tolerance of the sections, as well as to maintain any required welding gap tolerances between two superposed sections.
Once this operation is done, the internal gripper releases and the overhead crane then removes the internal gripper. At this point in time, an operator informs the LRT to initiate the assembly process from the LRT controller's interactive touch screen monitor. This action launches the LRT's initialization routine; the LRT rotates the vessel section while sensing with a laser scanner until it detects the section's vertical seam. Once the vertical seam is detected, the LRT controller establishes a positional reference relating to the vessel's CAD date.
The first section is then rotated to a position from which the internal robot can cut out the vessel's doorway opening, and then proceeds to cutting it out with its PLASMA cutting equipment. Upon completion of the cut, the vessel is rotated by the LRT to the manual assembly area and then comes to a stop.
Manual task information is then displayed to the LRT's controller touch screen regarding the installation and welding of the doorway's frame. The information displayed refers to the specifications of the vessel's doorway, it provides the welder and operator specific information referring to orientation, shape and dimensions pertinent to proper installation of the part, if required, any additional tasks to be performed such as repads to be welded to the perimeter of the cutout shape, or mechanical assembly information such as torque settings, bolt sizing, etc., can also be displayed. The doorframe is welded on to the vessel's exterior wall around the doorway cut out, and the LRT controller is notified once the task is completed. The cutting out and installation of the doorway allows workers to access the interior of the vessel when all four sections of the vessel's wall and the roof have been installed, thus allowing work to be performed from the inside of the vessel on the LRTs centre column.
INSTALLATION OF A SECOND SECTION—Upon completion of the previous task, the operator informs the LRT's controller via its touch screen, and initiates the following automated sequence. During this sequence, the vessel section is rotated and lowered by the LRT to a preprogrammed level and orientation for manual assistance during the stacking of the second section onto the first one. Once in the correct position, the LRT stops and advises via its touch screen display, the details of the next operational tasks. Then the second section of the vessel, previously formed to a cylindrical shape and vertically welded, is moved on top of the first section by the overhead crane with an internal gripper holding it from the top. This section is manually guided into position on top of the first section, aligned, and on a command to the LRT controller via one of its data input devices, the upper internal roller arms are actuated, thus positively positioning the second section in relation to the first. Thereafter, the crane is detached from the second section's internal gripper, which remains attached to the top of this section to maintain its cylindrical shape. Subsequently, an operator notifies the LRT's controller via its touch screen that the task is completed. Thereafter, the LRT system controller initiates an automated sequence for the internal and external welding of the horizontal joint seam between the two sections. During this sequence, both sections are rotated together by the LRT, while simultaneously both external robots weld two horizontal passes to the joint seam and the internal robot welds a single pass to the same joint seam from the inside.
Upon completion of the seam welding, the LRT system comes to a rest and advises operators to remove the internal gripper still attached to the top section. Once this task finished and the LRT control system is advised, the LRT control system automatically retracts all roller arms, lowers the sections to appropriate manual working height, and rotates the section assembly to a specified 155 orientation for the installation of the next section. Once this sequence is completed, operators are notified via one of the LRT controller displays to proceed with the installation of the next section.
INSTALLATION OF THIRD AND FOURTH SECTIONS—The process repeats itself as described above for the third and fourth sections of the vessel.
INSTALLATION OF A STIFFENING RING—Once all four sections have been assembly on the LRT, using the overhead crane, a prefabricated and formed stiffening ring is installed to the outer side of the fourth section wall. It is secured in position by actuating the automated internal roller arms. The LRTs controller is then informed of the installation of the stiffening ring via its touch screen by an operator. As a result, the LRT's controller launches the welding sequence for the stiffening ring. The ring's top and side seams are simultaneously welded by the two robots during a continuous specific speed rotation of the vessel by the LRT.
Upon completion of this sequence, the LRT's controller stops the rotation of the vessel, displays the next manual task to be performed, and awaits further input from the operator before proceeding.
ROOF INSTALLATION—Before the next LRT operation can be executed, the vessel's roof is manually or automatically shaped, assembled, and welded together. All roof options are installed on the roof as well as roof lifting lugs for handling purposes. The roof is lifted by the overhead crane by its lifting lugs, then positioned on top of the vessel's cylindrical shell, aligned accordingly, and then released on to the vessel. The overhead crane is detached from the roof. Thereafter, the LRT's controller is notified via its touch screen that the roof is in position. Then an automatic sequence is launched, where the LRT starts rotating the assembly at a specific speed and the two external robots weld the seam joint between the roof and the vessel wall.
When this operation is completed, the LRTs rotation ceases and robots come to a rest position. In the next sequence the vessel wall and roof assembly are lowered to an acceptable level above ground, permitting workers to remove previously welded roof lifting lugs, roof lifting lugs may not be required if using an adapted roof lifting device.
Again, once this operation is completed, the LRT is advised via manual input to its touch screen. At this time, the vessel assembly is at its lowest elevation within the LRT; all subsequent operations occur as the LRT raises the vessel assembly to a point when it will be totally submerged at ground level with all accessories installed. Fourth section accessories
Following the operator acknowledging the completion of the last task, the LRT lifts the fourth section of the vessel to a predetermined height, starts rotating the assembly, while simultaneously the two external robots etch on the section's wall the exact locations of all externally mounted accessories, then LRT positions the section in an appropriate location for the manual the manual welding of these accessories. This sequence may require that operators advise the LRT controller upon completion and the LRT then rotates by a half turn to allow access for the installation of accessories previously not accessible form the controlled safety manual work zone.
During these operations, the LRT % controller touch screen informs the worker of locations and orientations for all fourth section accessories, such as vessel lifting lugs, hauling pads, ladder dips, ladder and cage sections, and gauge board clips and sections to be attached to the surface of the vessel wall.
Prior to proceeding to the next step of assembly, an automatic unlatching sling is attached to the vessel's lifting lugs allowing for the crane operator to easily attach his hook when the time comes to remove the vessel from the LRT. The previous operation is required as, because when the time comes to remove the vessel it will no longer be possible to lower the vessel on the LRT as all vessel accessories will be installed onto the vessel, and may be protruding beyond the vessel wall, thus restricting it from being lowered to install any lifting devices such as slings.
INSTALLATION OF THIRD SECTION ACCESSORIES—Once all of these accessories are installed onto the vessel, an input from the operator confirms completion of all fourth section accessory installations, the LRT proceeds by raising the vessel assembly to expose the third section at a specific height from ground, and then the robotic etch process is launched for all third section external accessories as previously described above.
Thereafter, the LRT controller displays via its screen the positions and orientations of the third level accessories to be mounted to the vessel welt. At this level, ladder clips, ladder sections and cages, gauge board clips and gauge board sections, are installed to the surface of the vessel wall.
INSTALLATION OF SECOND SECTION ACCESSORIES—On this section of the vessel surface accessories such as ladder clips, ladder and cage sections, gauge board sections and clips, and platforms are installed. Contrary to the other section, the second section requires shapes to be cut out of the vessel wall allowing for the installation of a loading spout, couplings, a burner throat flange, and burner supports.
Once the previous manual task completed the LRTs controller is informed via its touch screen, the LRT then raises the vessel assembly to an appropriate working level, rotation is initiated for the external robotic etching of surface accessories, the cutting of pass through accessory holes with the internal robot, then the LRT stops, and displays relative accessories information for this level's accessories, and awaits an input to continue. At this time, an operator notifies the LRT controller, the LRT lifts and rotates the vessel assembly until the doorway access to the inside of the vessel is exposed and accessible for workers to enter the inside of the vessel onto the LRTs centre column. Once the vessel is positioned by the LRT, welders and operators are notified via the LRT controller display screen. Thereupon, workers enter the vessel onto the LRTs centre column, take control of the LRT via its handheld control unit, and rotate, lift, and/or lower the vessel assembly to accommodate the installations of all pass through accessories and internally mounted surface accessories. Pass through accessory installations commence with the installation and weld of any repads as required by the vessel's specifications, installation and tacking of all pass through accessories from the outside of the vessel, and complete welding of all pass through accessories from the inside and outside of the vessel, installing and welding of the burner support system inside the vessel, as well as installing and securing the burner inside the vessel.
Once all accessories installations are completed on the second section, workers exit the vessel and the LRT controller is informed. Upon completion of this last task, all workers exit the vessel, and the LRTs controller is informed via its touch screen control. The vessel is then raised to an appropriate height for the installation of all first section accessories from the outside and inside of the vessel.
INSTALLATION OF FIRST SECTION ACCESSORIES—The sequence of assembly of the second section accessories is then repeated for all first section accessories. This section requires ladder dips, ladder and cage sections, gauge board sections and clips, hauling pads, and enviro-vault hinges, if required, to be installed and welded to the exterior wall of the vessel, as well as pass through accessories such as flanges, and couplings. Once these tasks are completed workers exit the vessel and inform the LRT of completion.
FLOOR INSTALLATION—At this point in the assembly process the vessel is ready to be moved onto the floor. The floor previously assembled may have an enviro-vault sitting on its surface, is located at ground level on the plant floor within the immediate proximity of the LRT. The overhead crane lifts the vessel assembly off of the LRT, positions and aligns the assembly onto the floor, the crane than release the vessel from its automatic unlatching lifting sling. Once the vessel assembly is sitting on its floor, if required, the enviro-vault is moved into its proper position within the vessel. From thereon, the horizontal seam between the vessel wall and its floor is internally and externally welded, as well as, again it required, the enviro-vault to the vessel's floor and internal wall.
INSULATING, PAINTING, AND COATING—At this time, the vessel is ready to be insulated and thereafter painted, which may require moving the vessel to an explosion proof chamber. Once in the chamber, the vessel is insulated, externally painted, and internally coated if required.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiments without departing from scope of the Claims.
The present application is a continuation in part (CIP) of U.S. patent application Ser. No. 11/855,320, with which it has common inventors. In addition, the present application incorporates by reference and claims priority to U.S. provisional patent application No. 61/096,039, with which it has common inventors.
| Number | Date | Country | |
|---|---|---|---|
| 61096039 | Sep 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11855320 | Sep 2007 | US |
| Child | 12558470 | US |
