Methods for controlling charge accumulation while operating a mobile platform immersed in a hazardous, non-conductive substance

#Generally, this disclosure relates to devices and related methods for handling a mobile platform in a tank containing hazardous substances that may be non-conductive.

#Otherwise routine tasks may become exceedingly difficult if the ambient conditions pose a potential hazard to humans and/or the machinery required to perform those tasks. One such task is inspecting the structural integrity of tanks used to contain flammable substances such as liquid or gaseous hydrocarbons. Tank inspections typically include measuring the wall thicknesses at multiple locations of the tank structure. An out-of-norm thickness indicates the presence of corrosion, or some other type of damage, which left unchecked could create leak paths for the resident fluids. Unfortunately, inspections of walls making up a bottom or floor of a tank must be conducted from the interior of the tank in order to accurately assess the condition of these walls.

#A common approach to performing tank inspections is to use human work crews who enter the tank interior and scan the floors of tanks using magnetic and ultrasonic sensors. The tank must first be emptied of liquid contents and purged of all flammable substances to a sufficiently low concentration so that any sparks caused by equipment used by the work crews do not cause an explosion. The preliminary step of purging the tank is time consuming. Moreover, the tank must be decommissioned and taken out of service during the entire inspection process. Thus, manual tank inspections can be costly and disruptive to the ongoing operations of tank owners.

#For detailed understanding of the present disclosure, references should be made to the following detailed description of the disclosure, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:

#FIG. 1 sectionally illustrates a tank that may be inspected by using a mobile platform according to the present disclosure;

#FIG. 2 is a functional block diagram of one embodiment of a mobile platform in accordance with the present disclosure;

#The present disclosure provides devices, systems, and methods for performing tasks in a hazardous environment. For conciseness and clarity, the description below is principally directed to systems and related methods for inspecting a tank structure having an interior in which energetic materials such as hydrocarbon fluids are present. The present disclosure also provides devices, systems, and methods for handling mobile platforms used in a non-conductive, energetic substance. For conciseness and clarity, the description below is principally directed to systems and related methods for handling mobile platforms in a tank structure having an interior in which non-conductive, energetic substances, such as some classes of hydrocarbon liquids and gases, are present. However, it is emphasized that the present teachings can be readily applied to other industries and uses.

#Referring initially to FIG. 1, a tank 10 may be used to store an energetic substance, such as hydrocarbons, in the form of a liquid body 12 and a vapor 14. The fluid-tight tank may include a domed top wall 16, a generally planar bottom wall 18, and a cylindrical vertical wall 20. An interior 22 of the tank 10 may be accessed via a hatch 24. In some tanks, pillars 26 may be used for structural support or other uses. Also, it is common for the tank 10 to also contain objects 27, which may be intentionally placed such as sumps, piping, supports, etc. or foreign material such as debris, dropped tools, chains, wires, etc. The tank 10 may be a fixed above-ground tank or an underground tank. The tank 10 may also be positioned on a vehicle or vessel such as a barge, ship, land vehicle, etc. Moreover, the tank 10 may employ different configurations; e.g., the top wall 16 may be flat and/or an interior floating roof may be used. As will be evident from the discussion below, systems and methods of the present disclosure can perform inspections of the tank 10, and other similar structures irrespective of their usage, location, or design, with greater efficiency and safety than conventional tank inspection devices and methods.

#Referring now to FIG. 2, there is shown, in functional block diagram format, a non-limiting embodiment of an intelligent mobile platform 100 for performing one or more tasks in the tank 10 of FIG. 1. The mobile platform 100 may include an enclosure 200, a control unit 300, a propulsion system 400, and a power supply 500. Optionally, a task module 600 may also be carried by the mobile platform 100. As used herein, the term “carried by” means that the object is inside, attached to, or on the mobile platform 100. Hereafter, these structures and on-board equipment will collectively be referred to as “subsystems.” In some embodiments, the control unit 300 has bi-directional communication with one or more subsystems via a communication network 360. In other embodiments, communication may be in one direction to one or more subsystems. In still other embodiments, no communication is provided to or from some of the subsystems. The power supply 500 supplies power to one or more systems via a power distribution network 362, which may share circuitry with the communication network 360. The mobile platform 100 may be considered “intelligent” because the control unit 300 is configured to control the subsystems of the mobile platform 100 by using only previously programmed instructions and information acquired “real time” or “near real time” via on-board sensing instruments. That is, the mobile platform 100 can acquire information relevant to an assigned task and make decisions in furtherance of the completion of that task without human intervention. Therefore, advantageously, the mobile platform 100 may not have and may not require any umbilical, physical or otherwise, to a location external to a tank through which power or command signals are received. The subsystems of the mobile platform 100 are discussed in greater detail below.