Abstract:
Techniques for cleaning the inside of complexly-bent tubing are disclosed using a combination of minimal amounts of solvent and pneumatically propelled foam pellets. In order to increase device efficiency, an escapement apparatus employs a vacuum-assisted loading mechanism and retaining pin to reliably load one pellet at a time.

Description:
FIELD OF THE INVENTION 
   This invention relates to methods and systems for cleaning tube-like structures. 
   BACKGROUND OF THE INVENTION 
   The construction of a large and complex system, such as an aircraft or automobile, generally requires the manufacture of thousands of components and sub-components. For example, a particular aircraft will require the assembly and installation of a number of hydraulic systems to manipulate the aircraft&#39;s control surfaces, and the hydraulic systems will require the manufacture of shaped tubing to transport hydraulic fluid across the various components of the control systems. 
   It should be appreciated that the manufacture of even the simplest of components can require a large number of steps, and that one of the final steps before integration into a larger assemble can involve cleaning. For instance, using the hydraulic tubing example above, it can be desirable to remove organic and inorganic contaminates from the inside of the tubing before installing the tubing into a control system and charging (filling) the control system with hydraulic fluid. 
   While there are a number of available methods to clean tubing, such as letting the tubing soak for an extended period in a solvent bath, such methods are not economical when only a few pieces of tubing need cleaning at a time, or practical when the tubing needs cleaning in a very short time. Accordingly, new methods and systems for cleaning tubing are desirable. 
   SUMMARY OF THE INVENTION 
   One of the many advantages of using some elements of the invention is that it provides an inexpensive and fast approach to cleaning the inside of a given tube-like structure using very little energy and solvent. 
   For example, an apparatus for cleaning the inner-surface of a tube is described that includes a spraying portion having a connection to a solvent container and configured to apply solvent to the inner-surface of the tube, and a pellet-shooting portion configured to shoot one or more pellets into the tube thus wiping the tube clean of solvent and contaminants. 
   An escapement apparatus for sequentially launching pellets is also disclosed, the escapement apparatus having an escapement body with an embedded escapement channel, a first shuttle capable of controllably blocking the escapement channel at a first location along the length of the escapement channel, a second shuttle capable of controllably blocking the escapement channel at a second location along the length of the escapement channel and an air-flow assisted means to reliably draw pellets into an escapement chamber defined by the escapement channel and the first and second shuttles. 
   A method for cleaning the inside of a tube is disclosed that includes injecting a quantity of solvent into the tube, and subsequently injecting one or more pellets into the tube. A method for loading foam pellets into an escapement device is also disclosed that includes attracting a plurality of foam pellets into an escapement chamber using a forced gas flow, and activating a retaining mechanism to prevent all but a first pellet from entering the chamber. 
   There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described or referred to below and which will form the subject matter of the claims appended hereto. 
   In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
   As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  depicts an exemplary system for cleaning tubes. 
       FIG. 2  depicts details of the escapement device of  FIG. 1 . 
       FIG. 3  depict a first step in the operation of the escapement device of  FIG. 2 . 
       FIG. 4  depict a second step in the operation of the escapement device of  FIG. 2 . 
       FIG. 5  depict a third step in the operation of the escapement device of  FIG. 2 . 
       FIG. 6  depict a fourth step in the operation of the escapement device of  FIG. 2 . 
       FIG. 7  depict a fifth step in the operation of the escapement device of  FIG. 2 . 
       FIG. 8  depict a sixth step in the operation of the escapement device of  FIG. 2 . 
       FIG. 9  depict a seventh step in the operation of the escapement device of  FIG. 2 . 
       FIG. 10  is a flowchart outlining an exemplary operation according to the present disclosure. 
       FIG. 11  is a flowchart outlining a second exemplary operation according to the present disclosure. 
       FIG. 12  depicts a foam pellet useable in the disclosed cleaning methods and systems. 
   

   DETAILED DESCRIPTION 
   The enhancements of the invention(s) permit the cleaning of practically any form of tubing in a short time using very little solvent and energy.  FIG. 1  depicts a cleaning system  100  for cleaning the insides of tubing, such as the complexly-bent production tube  190  shown at the bottom right-hand corner. 
   As shown in  FIG. 1 , production tube  190  has a complex “S”-shape that would preclude a straightforward cleaning, e.g., forcibly ramming a piece or cloth or brush down the length using a metal rod, as could be done with a straight tube, or soaking the tube in a wasteful amount of solvent solution for an extended period of time. The present system  100  overcomes the shortcomings of prior cleaning approaches by first spraying an appropriate amount of solvent down the length of the production tube  190  (using an optional forced air flow to help move the solvent down the length of the tube) followed by pneumatically propelling a number of foam pellets through the production tube  190  in order remove contaminates and solvent by literally wiping the inside of the tube with the pellets. 
   As shown in  FIG. 1 , the cleaning system  100  includes an escapement device  110  and a solvent container  150  coupled to a fitting device  160  via respective hose  112  and solvent tube  152 . The escapement device  110  is also coupled to a container of foam pellets  120  via pellet supply tube  122 , a pressure source  130  via tube  132  and a vacuum source  140  via tube  142 . The pressure source  130  and the vacuum source  140  of the present cleaning system are air pumps. However, it should be appreciated that in other embodiments the pressure source  130  and the vacuum source  140  can take various other forms, such as pneumatic pressure bottles and the like. 
   In operation, a workman or other operator can attach production tube  190  to the fitting device  160 , which in the present embodiment can take the form of a gun-shaped handle capable of making an effective seal with the end of a tube. 
   Next, the workman can activate a first control (not shown) optionally located on the fitting  160  in order to start the cleaning process. The cleaning process of the present embodiment starts with the release of a proscribed amount of liquid solvent (provided by solvent container  150 ) through the fitting device  160  and into the tube. In the present embodiment the solvent is delivered as a thin stream of liquid assisted by a forcible air flow (provided by the escapement device  100 ). However, it should be appreciated that in other embodiments the solvent can be delivered as a stream, a fine mist or in any other advantageous form. Further, while the present embodiment uses forced air flow to aid in the distribution of solvent, it should be appreciated that in various embodiments forced air flow can be replaced by other means, e.g., gravity or added momentum, and even eliminated all together. 
   Once the solvent is applied and distributed within the production tube  190 , the escapement device  110  can retrieve a number of foam pellets one at a time from the pellet container  120  using the vacuum source  140  to aid retrieval, then forcibly propel the foam pellets one at a time using pneumatic pressure provided by the pressure source  130 . As each foam pellet is ejected from the escapement device  110 , the pellets travel through hose  112  and into the fitting device  160  where they are guided into production tube  190 . 
   As a given foam pellet travels along the length of the production tube  190 , it should be appreciated that the pellet will effectively wipe the inside of the tube and absorb contaminates and solvent along the way. Accordingly, it should be appreciated that the solvent serves two purposes: bringing contaminates into solution and acting as a lubricant for the pellets to prevent jamming. Further, it should be appreciated that it can be advantageous for the foam pellets to be formed having “open cells” capable of absorbing the solvent and contaminates, as opposed to having a smooth skin incapable of effectively passing fluids and small particles. 
   The inventors of the present methods and systems have determined that it is often advantageous to propel more than one pellet in the cleaning process, but that two pellets is very often an effective number. Accordingly, the present cleaning system  100  is configured to automatically propel two pellets after a single application of solvent. However, it should be appreciated that the cleaning system  100  can be configured to eject an amount of solvent between pellets and/or be configured to eject any number of pellets as may be advantageous or desirable. 
     FIG. 2  depicts an escapement device  110  capable of use with the cleaning system  100  of  FIG. 1  above. As shown in  FIG. 2 , the escapement device  110  includes an escapement body  210  having an escapement channel  212  running down the length of the body  210 , a retaining pin  220  located along the escapement channel  212 , a first shuttle  230  moveable within a first shuttle-guide  234  and located below the retaining pin  220 , a second shuttle  240  moveable within a second shuttle-guide  244 , a first pressurized gas port  250  and a vacuum port  260  located between the two shuttles  230  and  240  and along the escapement channel  212  and a second pressurized gas port  270  located below the second shuttle  240 . 
   In operation, the various components  220 - 270  can perform separate and distinctive functions. For example, as will be shown the following figures, the shuttles  230  and  240  with their respective holes  232  and  242  can act as switches depending on their particular position within their respective guides  234  and  244 . Similarly, the retaining pin  220  can act as a form of switch depending on its particular position within its respective guide. Further, the functionality of ports  250 ,  260  and  270  will be shown for their capacity to propel or attract pellets, and so on. 
     FIG. 3  depicts the escapement device  110  of  FIG. 2  in a first state where the retaining pin  220  is disengaged, the shuttles  230  and  240  are closed, a first pellet  290  in the chamber  255  defined by the shuttles  230  and  240  and the escapement channel  212 , a number of other pellets  292 - 298  are stacked above the first shuttle  230 , and the second pressurized gas port  270  is active, i.e., expelling pressurized gas to create an air flow exiting the escapement body  210 . 
   Referring back to  FIG. 1 , it should be appreciated that the present state of the escapement device is useful for providing an airflow that can be used to help transport a solvent through the length of a tube. That is, as solvent is released into production tube  190  from one end, the air flow created by port  270  can assist the solvent along the length of such tube. 
     FIG. 4  depicts the escapement device  110  of  FIG. 2  in a second state where the retaining pin  220  is disengaged, the first shuttle  230  is closed, the second shuttle  240  is open, the vacuum port  260  and the second pressurized gas port  270  are inactive and the first pressurized gas port  250  is active, i.e., expelling air. In the present state, the pressure buildup within chamber  255  due to the gas from port  250  can literally propel pellet  290  down through the bottom of the escapement device  110  much as a bullet is propelled from a gun. Referring back to  FIG. 1 , the present state is useful to propel a pellet through hose  112 , fitting  160  and the inside of production tube  190 . 
     FIGS. 5-9  depict a reloading of the escapement device  110  with  FIG. 5  depicting the escapement device  110  of  FIG. 2  in a third state where the retaining pin  220  is disengaged, the shuttles  230  and  240  are closed and all ports  250 ,  260  and  270  are inactive.  FIG. 6  depicts the escapement device  110  of  FIG. 2  in a fourth state where the retaining pin  220  is engaged, the shuttles  230  and  240  are closed and all ports  250 ,  260  and  270  are inactive. As shown in  FIG. 6 , the present state is useful in that the retaining pin  220  can hold pellet  294  in place without encumbering pellet  292 . 
   Continuing to  FIG. 7 , the escapement device  110  is depicted in a fifth state where the retaining pin  220  is engaged, the first shuttle  230  is open, the second shuttle  240  is closed, the pressurized gas ports  250  and  270  are inactive and vacuum port  260  is active. In response to the state depicted in  FIG. 7 , pellet  292  is drawn into the escapement chamber  255  by virtue of a combination of gravity and a differential pressure/air flow created by the vacuum port  260 . Meanwhile, pellets  294 ,  296  and  298  are precluded from entering the chamber  255  by virtue of the retaining pin&#39;s impingement of pellet  294 . 
   While in various embodiments the escapement device could function without using a vacuum port, i.e., by using gravity alone to draw pellets into the escapement chamber  255 , the inventors of the disclosed methods and systems have determined experimentally that using an air flow to assist each pellet along greatly increases the reliability of the escapement device  110 . Further, while it should be appreciated that the present system uses vacuum port  260  to create differential pressure and air flow, similar results might be attained by using other configurations, such as using a pressurized gas port above the pellets  292 - 298  to force air (and pellets) into the escapement chamber  255 . 
   Continuing to  FIG. 8 , the first shuttle is closed to seal pellet  292  into the escapement chamber  255 , and in  FIG. 9 , the retaining pin  220  is disengaged to allow pellets  294 - 298  to incrementally drop and to create a state substantially identical to that shown in  FIG. 3 . 
     FIG. 10  is a flowchart outlining an exemplary operation for operating a pneumatic tube-cleaning apparatus, such as the cleaning device and components described above. The process starts in step  1002  where a tube to be cleaned is attached to an appropriate fitting of the cleaning device. Next, in step  1004 , a workman/operator can activate a trigger to start the cleaning process. Control continues to step  1006 . 
   In step  1006 , an amount of solvent is released into the tube with an optional application of pressurized gas to assist the solvent down the length of the tube. Next, in step  1008 , an escapement device within the cleaning apparatus can open an appropriate shuttle (switch) and activate a first pressurized gas port (device) in order to pneumatically propel a foam pellet throughout the length of the tubing. Then, in step  1010 , the shuttle of step  1008  is closed and the first pressurized gas port is deactivated. Control continues to step  1012 . 
   In step  1012 , a retaining pin is engaged to hold fast a given pellet in a stack of pellets. Then, in step  1014 , a first shuttle is opened to allow a pellet located between the held pellet of step  1012  and an escapement chamber to fall into the escapement chamber. Then, in step  1016 , a vacuum port is activated to help draw the pellet of step  1014  into the escapement chamber. Control continues to step  1018 . 
   In step  1018  the first shuttle is closed. Next, in step  1020  the retaining pin is disengaged. Control then continues to step  1050  where the process stops. While the exemplary flowchart of  FIG. 10  describes a single cycle of solvent and pellet application, as discussed above it should be appreciated that steps  1002 - 1020  can be optionally repeated, or that steps  1008 - 1020  can be optionally repeated to encompass the use of multiple applications of solvent and/or pellets. 
     FIG. 11  is a flowchart outlining a second exemplary operation for operating a pneumatic tube-cleaning apparatus, such as the cleaning device and components described above. The process starts in step  1102  where a tube to be cleaned is attached to an appropriate fitting of the cleaning device. Next, in step  1104 , a pellet is ejected into a production tube. Then, in step  1106 , the ejected pellet is caught in a catching device, e.g, a mesh bag, so as to safely retain errant high-velocity pellets from injuring nearby people or damaging nearby equipment. Control then continues to step  1108 . 
   In step  1108 , a decision is made whether to eject one or more pellets. If more pellets are to be ejected, control jumps back to step  1104 ; otherwise, control continues to step  1110 . 
   In step  1110 . after no more pellets are to be ejected and subsequently caught, a blast of air is forced into the production tube in order to assure that there are no pellets stuck within the tube. Next, in step  1112 , an operator can count the pellets in the catching device (the “catcher”) in order to assure that all pellets used are accounted for. Control then continues to step  1250  where the process stops. 
     FIG. 12  depicts an exemplary foam pellet  1200  useful for cleaning tube-like structures. As shown on  FIG. 12 , the foam pellet  1200  is generally cylindrically-shaped with a top portion, a bottom portion and a round side. While not specifically shown, all surfaces of the exemplary pellet  1200  have porous surfaces: the advantage to the porous surfaces being its ability to readily absorb solvent and contaminates. 
   While the exemplary pellet of  FIG. 12  is cylindrical, it should be appreciated that the particular shape of a cleaning pellet can vary to encompass any number of useful shaped, such as bullet-like, round etc. Further, while the pellets of the exemplary methods and systems use porous surfaces, other surface types and textures including smooth surfaces, abrasive surfaces etc might also be utilized depending on the particular nature of a cleaning problem. 
   In various embodiments where the above-described systems and/or methods are implemented using a programmable device, such as a computer-based system or programmable logic, it should be appreciated that the above-described systems and methods can be implemented using any of various known or later developed programming languages, such as “C”, “C++”, “FORTRAN”, Pascal”, “VHDL” and the like. 
   Accordingly, various storage media, such as magnetic computer disks, optical disks, electronic memories and the like, can be prepared that can contain information that can direct a device, such as a computer, to implement the above-described systems and/or methods. Once an appropriate device has access to the information and programs contained on the storage media, the storage media can provide the information and programs to the device, thus enabling the device to perform the above-described systems and/or methods. 
   For example, if a computer disk containing appropriate materials, such as a source file, an object file, an executable file or the like, were provided to a computer, the computer could receive the information, appropriately configure itself and perform the functions of the various systems and methods outlined in the diagrams and flowcharts above to implement the various functions. That is, the computer could receive various portions of information from the disk relating to different elements of the above-described systems and/or methods, implement the individual systems and/or methods and coordinate the functions of the individual systems and/or methods to clean tubing using the methods and systems described above. 
   The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.