Abstract:
This disclosure concerns a typical inspection device of the invention. In some embodiments, the inspection device functions in a storage vessel, such as a underground fuel tank, including storage vessels that comprise an explosive mixture of gases. Also, this disclosure concerns a process for inspecting the inside of the storage vessel, in some cases creating a record of the image of the inside of the storage vessel. Invention processes do not require a step of inerting the vessel. Invention devices can operate in a vessel that has not been subjected to an inerting step.

Description:
BACKGROUND  
       [0001]    Inspecting the interior of underground vessels or other vessels carries with it an inherent risk. This risk is compounded when the vessel contains or has contained flammable material or other flammable liquids. 
         [0002]    One way of inspecting the interior of the vessel is to completely empty the vessel of liquid, excavate down to a manhole cover, usually located in the side of the vessel, and sending a person inside to inspect the vessel. This method is very time-consuming and expensive. It also carries a safety risk for the inspector. 
         [0003]    A more useful solution to inspecting the inside of the vessel is to enter the vessel with some sort of recording device and then in some cases, the entry can occur through the fill pipe into the vessel. But to use the fill pipe and avoid excavating to the manhole cover, the device must be able to fit through the sub-4-inch diameter fill pipe typically found in such vessels. And while in some cases, using such a video recording device allows the process to avoid completely emptying the vessel, the operator must still render the atmosphere inert. 
         [0004]    In order to avoid an explosion, an operator or an inspector must render the atmosphere of the vessel inert before placing any electrical device inside of the vessel. Rendering the atmosphere inert is to transform the headspace in the tank from an atmosphere containing any mixture of vapor and oxygen into an atmosphere containing a mixture of vapor and oxygen below the mixture&#39;s explosive limit. Since accomplishing this exchange of atmosphere takes hours of flushing with an inert gas, the smaller the volume to be flushed, the faster the process completes. The operator typically renders the atmosphere in the vessel inert using a procedure similar to the following procedure:
       1. Isolate product piping from tank, if possible, or use an inert gas to blow the product out of the product piping.   2. Isolate vapor recovery piping from the tank. If that is not possible, shut down the entire tank field during the inspection.   3. Plug all gas exits except the normal vent riser or pipe. If the vent pipe is not available, install a temporary vent pipe.   4. Place a grounded CO 2  hose into the headspace and introduce CO2 into bottom of empty tank   5. Verify that an accurate oxygen meter reads 21% O 2  in fresh air before and after every reading.   6. Take readings at the bottom, middle, and top of the headspace.   7. Continue flushing until all three measurements read less than 7% O 2 .   8. Monitor the O 2  levels inside of the tank during the video inspection.       
 
         [0013]    Once the inspection has begun, the oxygen level inside of the vessel must be continuously monitored or at least monitored every 15 minutes by measuring the oxygen level at the bottom, middle, and top of the headspace. This too, increases the time and expense of conducting the inspection. 
         [0014]    Moreover, the requirement that the recording device fit within a sub-4-inch fill pipe presents problems, as well. Most recording devices cannot meet this requirement. One that can is a fiber-optic camera. But fiber-optic cameras have a very short focal length, which means that the fiber-optic camera must be brought much closer to the surface being inspected. Also, fiber-optic cameras have a much narrower field of vision, which means that they record a much smaller area of the interior of the vessel per unit of time then a standard scale video camera. Aside from the camera, safely inserting a light source that is bright enough to adequately illuminate the tank interior during the inspection is troublesome, as well. The main trouble again is that an adequate light source is usually too large to pass through the sub-4-inch fill tube into the interior of the tank. 
         [0015]    What is needed is a video camera that can enter through the fill pipe of the vessel, record and inspect the interior surface of the vessel in a reasonable amount of time, and do this without employing the long inerting procedure discussed above. 
       SUMMARY  
       [0016]    The current disclosure concerns a typical inspection device of the current invention. In some embodiments, the inspection device functions in a storage vessel, such as an underground fuel tank, including storage vessels that comprise an explosive mixture of gases. Also, the current disclosure concerns a process for inspecting the inside of the storage vessel, in some cases creating a record of the image of the inside of the storage vessel. Invention processes do not require a step of inerting the vessel. Invention devices can operate in a vessel that has not been subjected to an inerting step. 
         [0017]    In a version of the current inspection device, the inspection device comprises a control unit situated outside of the vessel, a head unit adapted to passthrough the fill pipe into the vessel, with an umbilical cord connecting between the control unit and the head unit, and a handle to manipulate the head unit. In some embodiments, the control unit comprises any one or any combination of a power supply for the device including for the head unit, various circuitry for control of energizing the head unit, de-energizing the head unit, the video camera, the video recording device or devices, the lights in the head unit, the gas flow rate or gas pressure, and de-energizing the head unit when sensors in the control unit or sensors in the head unit indicate insufficient gas flow rate or gas pressure—thus the head unit operates in a fail-safe manner. 
         [0018]    Additionally, invention inspection devices can comprise a head unit. In use the head unit is a part of the inspection device that enters the vessel and comprises any one or any combination of a video camera, lights, gas inlet ports, mechanisms that allow remote control over where the video camera points or focuses, and gas flow rate or gas pressure sensors. Invention inspection devices employ video cameras as described below comprising any one or any combination of zoom controls, focus controls, and optics. Either or both of zoom controls and focus controls can communicate with the control unit through a wired or wireless signal pathway. In some embodiments employing a wired pathway, the wires run from the control unit to the head unit such that the function of the device causes the wires to remain inside of a substantially inert atmosphere or gas. The video camera optics have a depth of field such that the camera can focus on any region of the vessel interior to provide an image with good enough quality for a skilled inspector or engineer to use the image to accurately evaluate the condition of the vessel wall. Head unit lights provide enough illumination so that the camera can focus on any region of the vessel interior to provide an image with good enough quality for a skilled inspector or engineer to use the image to accurately evaluate the condition of the vessel wall. 
         [0019]    Invention inspection devices can comprise an umbilical cord that connects between the head unit and the control unit. The umbilical cord comprises any one or any combination of a gas line, power cables passing through the gas line, or signal or data cables passing through the gas line. In embodiments that have power cables passing through the gas line, the electricity delivered to the head unit can serve to power the head unit. In embodiments that have signal wires passing to the gas line, the signal wires can carry control signals to the various components of the head unit and can receive video signals from the video camera. 
         [0020]    Operationally, an invention process comprises inserting the head unit into the vessel. In some embodiments, the head unit passes through a fill pipe or other access pipe or fitting to enter the vessel. In some embodiments, the head unit has the correct dimensions to pass through the fill pipe. After the head unit is placed into the vessel, or at any time prior to entering the vessel, a flow of inert gas starts, and the gas flow enters the head unit such that all of the electrical components of the inspection device that are inside the vessel are contained in an inert atmosphere. Afterwards, the video camera is directed at the interior surface of the vessel and in some embodiments, the inspector records the video signals creating a movie of the entire inside surface of the vessel or any portion of the inside surface of the vessel that the inspector desires to view. The inspector can also display the video signals in real time on a monitor connected to the control unit or separate from the control unit. The head unit can be inserted into the vessel and safely used to record the condition of the Interior of the vessel without risk of an electrical spark causing a fire or explosion. Thus, invention processes can record the interior of the vessel without relying on the hours-long inerting process. Therefore, invention processes can be much faster than prior art processes. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0021]      FIG. 1  depicts a block diagram of an embodiment of the Vessel Inspection System. 
           [0022]      FIG. 2  depicts a block diagram of an embodiment of the Head Unit of the Vessel Inspection System. 
           [0023]      FIG. 3  depicts the front of an embodiment of a Head Unit of the Vessel Inspection System. 
           [0024]      FIG. 4  depicts a block diagram of a Control Unit of the embodiments of the Vessel Inspection System. 
           [0025]      FIG. 5  depicts the rear of the head unit of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The following description of several embodiments describes non-limiting examples that further illustrate the invention. All titles of sections contained herein, including those appearing above, are not to be construed as limitations on the invention, but rather they are provided to structure the illustrative description of the invention that is provided by the specification. 
         [0027]    Unless defined otherwise, all technical and scientific terms used in this document have the same meanings as commonly understood by one skilled in the art to which the disclosed invention pertains. The singular forms “a”, “an”, and “the” include plural referents unless the context clearly indicates otherwise. Thus, for example, reference to “fluid” refers to one or more fluids, such as two or more fluids, three or more fluids, etc. 
         [0028]    The features, aspects, and advantages of the invention will become more apparent from the following detailed description, appended claims, and accompanying drawings. 
         [0029]    As shown in  FIG. 1 , device  50  of this invention comprises three major units: control unit  100 , umbilical cord  120 , and head unit  130 .  FIG. 2  shows a block diagram of head unit  130 , specifically a diagram showing some of the internal components of head unit  130 . Head unit  130  comprises camera  210 , lights  220 , and power supply  230 . In some embodiments, head unit  130  may optionally contain an internal microphone (not shown). Camera  210  is sometimes referred to as a video camera. 
         [0030]    Power supply  230  provides the correct voltage required by camera  210  and lights  220 . For purposes of this disclosure, “power” and “electrical power” are used interchangeably. As shown in  FIG. 3 , the internal components of head unit  130  are located within housing  310 , which protects the internal components and which serves as a rigid member within which to physically fix the internal components of head unit  130 . Additionally, housing  310  connects to and provides a passage for umbilical cord  120  to the interior of head unit  130 . 
         [0031]    Control unit  100  is shown in  FIG. 4  as a block diagram. Control unit  100  comprises video control  410 , signal controller  420 , light control  430 , power controller  440 , and optionally a gas controller  450 . Additionally, control unit  100  comprises an internal video recorder  460  or a signal directing apparatus that can switch or otherwise direct the video signal from camera  210  through control unit  100  out to a device for recording the video signals from camera  210 , that is, some type of external video recorder. 
         [0032]    Device  50  optionally comprises handle  320 , as shown in  FIG. 3 . Handle  320  mounts to head unit  130  through articulation  330 . In some embodiments, articulation  330  comprises an assortment of rigid brackets  340  connecting between handle  320  and head unit  130 . In some embodiments, handle  320  is a hollow tube with manipulating tube  350  disposed within handle  320  and operable in an up-and-down or back-and-forth direction. The lower end of manipulating tube  350  connects to at least one rigid bracket  340  such that the up-and-down motion translates into up-and-down motion of tip  360  of head unit  130 . 
         [0033]    Umbilical cord  120  passes power to head unit  130 . In some embodiments, umbilical cord  120  passes video signals and nonflammable gas from head unit  130  to control unit  100 . That is, in some embodiments, umbilical cord  120  functions as a gas line. In these or other embodiments, umbilical cord  120  functions as a signal pathway. 
         [0034]    Head unit  130  further comprises a substantially airtight canister movably connected to handle  320  in an articulated fashion. Head unit  130  comprises camera  210 , which itself comprises a lens  370  disposed such that lens  370 ′s field of view extends out from tip  360  of head unit  130 . Head unit  130  additionally comprises lights  380  that connect to light control  430  and that are disposed around lens  370  set into or attached to tip  360 . In some embodiments, camera  210  comprises optics that comprise one or more of a focusing mechanism, a zoom mechanism, and an F-stop adjustment mechanism. 
         [0035]    In some embodiments, head unit  130  additionally comprises an internal gas cylinder. In these or other embodiments, head unit  130  connects to an external gas source. In some embodiments, head unit  130  has an overall diameter small enough to enter the fill pipe of an underground vessel. In these or other embodiments, head unit  130  has an overall dimension in its smallest dimension of less than 4, 3, 2, or 1 inches. 
         [0036]    In some embodiments, head unit  130  additionally comprises a gas pressure sensor, a gas flow sensor, or some other sensor that functions to measure gas flow or gas pressure. The sensors connect to a normally open switch placed inside head unit  130  and designed to disrupt power should the gas stop flowing at a predefined rate or the pressure drop below a predefined level. In other embodiments, these sensors connect to signal wires leading out of the vessel or to control unit  100 . Head unit  130  additionally comprises an entrance  510  for umbilical cord  120  to connect to head unit  130 . In some embodiments, entrance  510  also serves as an entrance for a gas. In other embodiments, gas enters through a separate gas entrance. 
         [0037]    Umbilical cord  120  may comprise electrical wires to power the various components contained in head unit  130 . In some embodiments, umbilical cord  120  additionally comprises cables for transmitting video signals from camera  210  out of the vessel or to control unit  100 . In some embodiments, umbilical cord  120  additionally comprises cables for transmitting control signals from outside the vessel or from control unit  100  into the vessel and into head unit  130 . In some embodiments, these control signals carry instructions to camera  210 , lights  220 , or to power supply  230 . Umbilical cord  120  comprises a casing that is substantially gas tight through which one or more of the electrical wires or connections pass, in some embodiments. Typically, “substantially gas tight” means that whatever amounts of gas that leak out of the casing are small enough so that, despite leakage, the gas within the casing prevents liquid or vapors from entering into the casing. While perhaps most convenient, umbilical cord  120  need not contain a single casing. In other words, umbilical cord  120  may comprise more than one casing, tube, etc. 
         [0038]    In some embodiments in which umbilical cord  120  comprises a substantially gas tight casing, the casing serves as the conduit for gas from outside the vessel into housing  310 . In some embodiments, umbilical cord  120  runs freely from control unit  100  to entrance  510 . In other embodiments, umbilical cord  120  attaches to the outside of handle  320 . And in some embodiments, umbilical cord  120  is further constrained by routing it down handle  320 , through hollow tube and manipulating tube  350 . 
         [0039]    Control unit  100  sits outside of the vessel and connects to head unit  130  through umbilical cord  120 . Control unit  100  comprises one or more of the following: video control  410 , signal controller  420 , gas controller  450 , video recorder  460 , and pressure sensor-flow sensor  470 . 
         [0040]    Video control  410  comprises hardware-software combinations that allow remote control of camera  210 . Depending upon the available controls on camera  210 , video control  410 &#39;s hardware-software combinations can provide remote control of F-stop settings, zoom control, and focus control, etc. 
         [0041]    Light control  430  provides control over lights  220  using hardware-software combinations that allow for remote control over the functionality of lights  220 . In some embodiments, that control extends to controlling the brightness of lights  220  and turning lights  220  on or off. In some embodiments, light control  430  controls or is controlled by video control  410 . 
         [0042]    Signal controller  420  comprises hardware-software combinations that control the video signal from camera  210 . Typical parameters that signal controller  420  controls include starting the video signal, stopping the video signal, displaying the video signal in real time on an optional monitor (not shown), routing the signal to a video recorder  460  integral with control unit  100 , or routing the signal to an external video recorder, among other functions. 
         [0043]    Power controller  440  controls the down-hole power to head unit  130 . In some cases, power controller  440  provides a constant voltage to power supply  230  that power supply  230  modifies into whatever voltages the components of head unit  130  require. Alternatively, power supply  230  supplies the desired voltages to head unit  130 . The ability to turn the power to head unit  130  on or off is contained in power controller  440 . 
         [0044]    In some embodiments, power controller  440  communicates with optional gas controller  450  or pressure-sensor-flow-sensor  470 . This connection allows the power controller  440  to immediately shut off power to head unit  130  if gas pressure or gas flow ceases. Thus, it serves as a failsafe. 
         [0045]    In some embodiments, control unit  100  further comprises a gas outlet or hose bib. In these or other embodiments, control unit  100  further comprises a gas inlet. 
         [0046]    Handle  320  comprises a hollow tube that connects to head unit  130  through a movable connecting assembly. Handle  320  extends up through the fill tube and protrudes out of the vessel far enough so that the end extending from the vessel can manipulate head unit  130  within the vessel by manipulating handle  320  and inner tube  350  outside of the vessel. In some embodiments, the outer end of handle  320  connects to or mounts in a base situated above the fill tube to aid in steadying handle  320  and hence head unit  130 . In some embodiments, the mount can be moved stepwise or continuously using a stepping motor or the mount can be moved manually. In some embodiments, the base provides the ability to incrementally move handle  320  into or out of the vessel. In some embodiments, handle  320  is hand-held. 
         [0047]    In operation, the operator introduces head unit  130  into a vessel. At that point, the operator can manipulate handle  320 , rotating it around its cylindrical axis, which in turn rotates head unit  130 , as the operator desires, in the axial direction. Similarly, the operator can manipulate inner tube  350  in an up-and-down fashion, which causes tip  360  of head unit  130  to move up and down in a vertical direction. 
         [0048]    This ability to position tip  360 , lens  370  end, axially and vertically, gives the operator the ability to point head unit  130  at any interior surface of the vessel. This, combined with the ability of head unit  130  to zoom and focus on near and distant objects, allows optical inspection of the entire surface from a central point within the interior of the vessel. Similarly, camera  210  can focus through liquids remaining in the vessel. 
         [0049]    Once the operator correctly positions head unit  130 , control unit  100  operates to begin gas flow. Gas flows from the gas tank, through control unit  100 , through umbilical cord  120 , into head unit  130 . This gas flow, in embodiments using inert gas, can leak through any openings that may be present in head unit  130 . This flushes any air that was in head unit  130  out of housing  310  and replaces it with inert gas. Despite being in a potentially explosive environment, the electrical components of head unit  130  that could generate electrical sparks are in a region of gas lacking enough oxygen to reach an explosive mixture with vapor in the vessel. 
         [0050]    Upon the gas pressure reaching a high enough value or the gas flow rate reaching a high enough value, the pressure or flow sensor in control unit  100  or in head unit  130  or in both activates, allowing the power controller  440  or power supply  230  to power up the electronics in head unit  130 . Instead of or in addition to using an external gas tank or cylinder head unit  130  may contain an internal gas cylinder for flushing head unit  130  and rendering its atmosphere inert. In these or other embodiments, control signals can also depart to and arrive from control unit  100  and head unit  130  wirelessly. In these or other embodiments, the power supply for head unit  130  is a battery inside of head unit  130 . 
         [0051]    The system uses these types of procedures to insure that no electrical power reaches head unit  130  until its atmosphere has become inert. For purposes of this disclosure, inert means that all parts of umbilical cord  120  (in embodiments containing an umbilical cord  120 ) and head unit  130  have been flushed with inert gas such that the ratio of oxygen to vapor remaining in umbilical cord  120  and head unit  130  is below the explosive limit. 
         [0052]    Once the gas pressure and gas flow have reached the desired level, inspection of the interior of the vessel progresses as with other inspection methods known to those of ordinary skill in the art. The head unit powers up and the operator focuses the video camera on the inside of the vessel. This video signal displays in real time on a monitor and is recorded, if desired. In some embodiments, the total amount of time needed to finish a recording of a complete vessel inner surface is 1.5, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, or 0.66 seconds per square foot of interior area. 
         [0053]    While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications can be made without departing from the embodiments of this invention in its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as fall within the true, intended, explained, disclose, and understood scope and spirit of this invention&#39;s multitudinous embodiments and alternative descriptions. 
         [0054]    Additionally, various embodiments have been described above. For convenience&#39;s sake, combinations of aspects composing invention embodiments have been listed in such a way that one of ordinary skill in the art may read them exclusive of each other when they are not necessarily intended to be exclusive. But a recitation of an aspect for one embodiment is meant to disclose its use in all embodiments in which that aspect can be incorporated without undue experimentation. All patents, test procedures, and other documents cited in this specification are fully incorporated by reference to the extent that this material is consistent with this specification and for all jurisdictions in which such incorporation is permitted. 
         [0055]    Moreover, some embodiments recite ranges. When this is done, it is meant to disclose the ranges as a range, and to disclose each and every point within the range, including end points. For those embodiments that disclose a specific value or condition for an aspect, supplementary embodiments exist that are otherwise identical, but that specifically exclude the value or the conditions for the aspect. 
         [0056]    Finally, headings are for the convenience of the reader and do not alter the meaning or content of the disclosure or the scope of the claims.