Patent Application
20060054202
1. Field of Art
This application relates to remotely operated devices for the cleaning of the interior surfaces of enclosed spaces, such as storage tanks, via water or other fluid streams directed at the surface. With further particularity, this invention relates to a remotely operated apparatus especially suitable for the cleaning of storage tanks within vessels, such as ships, boats, and barges, the apparatus requiring limited human entry into the enclosed space in order to efficiently carry out the cleaning.
2. Related Art
There have been many efforts to develop semi- or fully automated cleaning devices for the cleaning of surfaces. Non-enclosed surfaces, such as flooring in a large warehouse, driveways, etc. pose no particular problem, as personnel can with relative ease and safety use a conventional hose and nozzle to direct a stream of water or other fluid onto the surface. Other applications may utilize high volume and/or pressure “pressure washers,” but the task still presents relatively few issues when non-enclosed spaces are involved.
Much more significant issues arise in the cleaning of enclosed spaces or areas. Personnel entry into such enclosed spaces can be difficult, with ingress and egress often confined to relatively small hatches through which personnel and equipment must pass, often multiple times. Of much more importance are the significant safety issues which are well known in the industry to be associated with work in enclosed spaces; for example, safety issues associated with maintenance of a safe breathing environment. While various devices and procedures have been developed to address such issues, such as various breathing apparatus and the like, there remain significant hazards associated with enclosed space work.
While there are many settings in which enclosed space work arise, one common one is associated with tanks which are present on vessels used in marine service, such as boats, ships, and barges. Such tanks are usually within the “body” of the vessel, and often are used to carry different fluids from time to time; therefore, it is important to clean the interior surfaces of the tanks between uses. While not limiting the scope of the present invention, it is convenient to address the present invention in the context of the cleaning of tanks on vessels used in support of the offshore oil and gas industry, in the Gulf of Mexico and elsewhere.
Supply boats are frequently used to transport drilling mud and other products to offshore drilling rigs, in support of oilfield drilling programs associated with offshore developments. The mud holding tanks in these boats vary in size. The average size tank is generally rectangular, on the order of 15 feet by 20 feet, with corrugated walls and a wall height of twelve to fifteen feet. Some of the newer boats have round, horizontal tanks.
When drilling mud is shipped to and from the rig, some of the solids in the mud often settle out onto the floor and walls of the tanks. As a result, the tanks require interior cleaning when the boat goes off charter or when a different type of mud is to be carried in the tank.
Current methods of cleaning involve a manned entry into the tank, in order that one or more personnel can manually wash the solids from the interior surfaces out using hoses and pumps (often fire hoses fed by pneumatic diaphragm pumps). The personnel manipulate the hoses and nozzles so as to follow a desired pattern of cleaning the floor and walls of the tank. While the pattern will vary according to the degree of cleaning needed, the volume of fluid being provided for the cleaning function, etc., generally the cleaning pattern involves sequential spraying of the dirty surfaces and “pushing” (via the high pressure/volume fluid stream) the solids and contaminated cleaning fluid to one or more collection points, to suction the solids/liquids from the tank. It can be readily appreciated that for greatest efficiency, any automated system would, to the extent practicable, mimic the cleaning pattern that a person could implement.
As described above, and as can easily be understood, methods involving personnel entry into the tank are a concern to the industry due to the risk exposure and the production limitations put on the workers in the tank. The primary risk to the personnel in the tank arises out of the unsafe conditions of the inside of the typical tank on a vessel. The majority of the mud tanks have a metal, sloped floor that is covered with relatively slippery materials. The personnel are required to wear rubber boots that add to the slippery nature of the floor conditions, and in the typical scenario are required to wash the interior surfaces using a water pressured nozzle to push the solids, etc. mud to a suction hose. Additionally, the personnel are required to wear a breathing air mask with air supply attached thereto, a harness and rubber suit.
In short, these safety requirements and unsafe conditions are a great concern to the industry and need exists for improved apparatus and method for automation of cleaning of interior tank surfaces.
The apparatus and method of the present invention comprise an improved system for the remotely controlled cleaning of interior tank surfaces, especially tanks within motor vessels. The system, in one presently preferred embodiment, comprises one or more arm assemblies, each comprising a plurality of connected hinged-together arm sections. One or more of the arm sections may be telescopic. A means for rotating each arm section with respect to the next, which in a presently preferred embodiment is a hydraulic rotary actuator, is disposed at each hinge point, and permits the operator to move the arm sections in a controlled manner over effectively a large (180 to 360 degree) arc of one arm section with respect to the next. Overall, the arm assembly can be folded into a relatively compact position, for lowering with a frame and hoist assembly positioned over an access hatch, into a tank to be cleaned. Once the arm assembly is inside the tank, it is moved (via a conveyor assembly, such as an overhead track mounted in the tank, with the arm assembly suspended from the track via a sliding or rolling carriage) and positioned at a mount on the inner surface of the tank. The mount may be positioned on a wall, the floor, or the ceiling of the tank. Alternatively, the arm assembly may be dismantled (for example, into the separate arm sections) and installed piece by piece, if no conveyor assembly is in place within the tank. Yet another alternative embodiment mounts within the access hatch, requiring no personnel entry into the tank. A fluid nozzle is mounted near the end of the arm assembly distal from the mounting point, with a hose routed down the arm assembly to the nozzle. A pump capable of relatively high volume and pressure output supplies fluid (water, chemicals, or other desired fluids) through the hose to the nozzle. A video camera is mounted on the arm assembly, preferably near the nozzle, to permit an operator to remotely view the cleaning process and area. In addition to or in lieu of the nozzle, a suction assembly may be mounted on the arm assembly. Additional cameras may be mounted within the tank. A control panel, preferably contained within a control room, is remotely located where an operator can fully control the apparatus, including fluid flow, suction hose (if any), position of the arm assembly, and direction of fluid flow from the nozzle. In a presently preferred embodiment, an umbilical carries the video signal from the camera to the control panel, and also contains hydraulic supply to the rotary actuators and control lines to the rotary actuators from the control panel. The very large arc through which the individual arm sections can move, and the manner in which the arm sections are connected, the mounting of the nozzle preferably on dual rotary actuators, yield 4 axes of movement of the nozzle. Telescopic capability of the arms adds still more flexibility of movement. All of these structural attributes and controls permit replicating the cleaning pattern that a human would effect within the tank.
The contaminated solids/fluid mix resulting from the cleaning process can be pumped from the tank via a discharge pump to a holding vessel, such as a disposal barge. Although limited personnel entry may be required to mount and dismount the arm assembly at the start and end of cleaning jobs, the remainder of the job may be carried out remotely and at least partially automated.
The present invention, in a broad sense, is directed to apparatus and method for a remotely operated system for the application of fluid streams onto surfaces. It is understood that the scope of the present invention encompasses applications in both enclosed and non-enclosed spaces, although it has particular application in enclosed spaces. The present invention is suitable for use in performing a number of different services, including but not limited to hydro blasting, sand blasting and chemical spraying, vacuum or suction device positioning, in any type of enclosed or non-enclosed space. For illustrative purposes only, and for convenience in setting forth one of the presently preferred embodiments of the invention, the invention will be described in connection with the cleaning of tanks on vessels, in particular example those tanks associated with the drilling industry, wherein those tanks are used in the transport of drilling muds. With reference to the drawings, some of the presently preferred embodiments are now described.
Referring to
A control panel 70 is conveniently yet remotely positioned with respect to the tank, and is preferably disposed within an enclosure such as a control room. Electrical power, etc. as required are supplied to the control panel. In addition, a hydraulic power supply 75 provides pressurized hydraulic fluid to the components, especially the hydraulic rotary actuators, of arm assembly 20. In other embodiments of the invention, electric AC/DC drive actuators may be used, in which case suitable electric power is supplied to the drives and controlled at the control panel.
Controls mounted on control panel 70 are operatively connected to arm assembly 20, and more particularly to a means for rotating arm sections 21 and 22 with respect to one another. It is understood that one or both of arm sections 21 and 22 may be telescopic, i.e. may be longitudinally extended or retracted, as controlled by the operator. In a presently preferred embodiment, the means for rotating the arm sections comprises rotary hydraulic actuators 90 disposed between arm sections (as shown in
Nozzle 60 is mounted to arm section 22 by one or more means for rotating nozzle 60. In a preferred embodiment, as seen in
It is understood that means for rotating 90 through 93 may comprise various structural elements (for example, simple king pin type arrangements to carry vertical and horizontal loads and torque; coupled with hydraulic cylinders with offset moment arm mounts, etc.), but in the preferred embodiment comprise rotary hydraulic actuators. These devices combine the required structural connection between arm sections, between the arm assembly and the mount (described in more detail below), and between the nozzle and the arm assembly, with the ability to induce rotation between the parts so connected, in a powered yet controlled manner. While various manufacturers may make suitable devices, one manufacturer which makes hydraulic rotary actuators is HELAC Corporation in Enumclaw, Wash., USA, in particular the “L” series models. It is understood that various other means for rotating could be used, and would fall within the scope of the present invention. As mentioned above, electric AC/DC actuators may also provide suitable structural capability while at the same time provide suitable motion and braking capability.
A second pump, denoted as discharge pump 110, can be used to pump out contaminated fluids and solids resulting from the cleaning, into another container for disposal, for example into disposal barge 120. Preferably, discharge pump 110 comprises a self-priming centrifugal pump, although it is understood that other types of pumps, for example a pneumatic diaphragm pump, are also suitable.
Referring to
The advantages of the present invention can be readily seen. Other than limited entry of personnel to mount and dismount arm assembly 20 and its associated equipment, operation of the system is done remotely, by an operator at control panel 70. The operator can bring nozzle 60 to bear in nearly any desired point within tank 30, and push fluids and solids to discharge pump 110. The significant safety hazards with personnel in an enclosed space are largely avoided. In addition, since the arm assembly 20 is capable of manipulating a nozzle/hose combination moving a much higher volume and pressure of fluid than can a human, cleaning time can be very much shortened.
Mount 200 may be disposed on a wall, the floor, or the ceiling of the tank. In the preferred embodiment of the invention, mount 200 is mounted in a more-or-less permanent manner within the tank, and remains in the tank between cleaning jobs. In this way, only arm assembly 20 need be removed and replaced between jobs. Alternative mounting configurations include mounts fixed to the ceiling of the tank, or a pedestal mount on the floor of the tank. One advantage to a floor pedestal mount (in particular, more or less in the center of the floor) is that full 360 degree rotation of the arm assembly would be possible; other mounts, for example wall or ceiling mounts, may be limited to on the order of 180 degree of rotation at the first point of rotation (that is, next to the mount).
While the preceding description sets out many specificities, it is to be understood that same are made by way of describing some of the presently preferred embodiments and not by way of limitation. Various changes could be made to the apparatus while still falling within the scope of the present invention. For example, the following changes comprise embodiments that fall within the scope of the present invention:
Therefore, the scope of the invention is not to be measured by the specific embodiments set out above, but by the scope of the appended claims and their legal equivalents.
