Patent Publication Number: US-2010116297-A1

Title: System and method for component recovery

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of Contract No. N00019-02-C-3003 awarded by the United States Navy. 
    
    
     BACKGROUND 
     In the aeronautical, aerospace and other industries, the components used are frequently expensive. Due to the high cost of many components, component refurbishment processes are important to return expensive components to service. Refurbishment often includes the removal of field contaminants and coatings or bonding compounds so that new coatings or bonding compounds can be applied to the component. 
     Refurbishment is generally done by immersing the component in tanks with sufficient amounts of chemicals to clean and/or strip the undesired contaminants, coatings, and bonding compounds. Typically, multiple tanks are needed for the multiple chemicals used in the refurbishment process. Each chemical generally requires its own individual tank. The larger the component, the larger the tank needed and the larger the amounts of chemicals needed to effectively refurbish the component. 
     This type of refurbishment process offers several disadvantages. First, a high volume of chemicals is needed to provide an immersion tank in which the entire component can be immersed. Chemicals used in the refurbishment process are often expensive. The greater the amount of chemical needed, the greater the expense will be for the refurbishment process. Second, many of the chemicals used in the refurbishment process are hazardous to the environment. The proper waste disposal of chemicals used in the refurbishment process involves additional expenses. When large amounts of chemicals are used in the immersion tanks as described above, large expenses are incurred to properly dispose of the large amounts of chemicals. Also, because many of the chemicals are hazardous, workers involved in the refurbishment process are also required to take the appropriate health and safety precautions. These precautions may provide additional expense. Third, when multiple immersion tanks are used in the refurbishment process, a large area often needs to be reserved for the tanks. When large tanks and a great number of tanks are needed, the refurbishment system may occupy a great deal of space. 
     SUMMARY 
     An exemplary embodiment of the present invention is a refurbishment system that includes at least one fluid feed tank, a refurbishment compartment, and at least one waste tank. A first fluid line connects the at least one fluid feed tank to the refurbishment compartment. A second fluid line connects the refurbishment compartment to the at least one waste tank. 
     A further exemplary embodiment of the present invention is a method for refurbishing a component. The method includes placing the component in a refurbishment compartment and delivering a first fluid to the refurbishment compartment. The method also includes removing the first fluid from the refurbishment compartment and delivering the first fluid to a first waste tank. The method further involves delivering a second fluid to the refurbishment compartment and removing the second fluid from the refurbishment compartment and delivering the second fluid to a second waste tank. 
     Another exemplary embodiment is a refurbishment system that includes at least one fluid feed tank, a refurbishment compartment having at least one fluid delivery element and a drain, and at least one waste tank. A fluid line connects the at least one fluid feed tank to the at least one fluid delivery element. The refurbishment system also includes a feed pump configured to deliver fluid through the fluid line. A recirculation line connects the refurbishment compartment drain to the at least one fluid delivery element and to the at least one waste tank. The refurbishment system also includes a waste pump configured to deliver fluid through the recirculation line. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of one embodiment of an apparatus for component recovery. 
         FIG. 2A  is a schematic illustration of a chemical application cycle. 
         FIG. 2B  is a schematic illustration of a chemical recirculation cycle. 
         FIG. 2C  is a schematic illustration of a chemical waste collection cycle. 
         FIG. 2D  is a schematic illustration of a chemical rinse and collection cycle. 
         FIG. 3A  is a schematic illustration of one embodiment of an apparatus for component recovery with a basket during a chemical application cycle. 
         FIG. 3B  is a schematic illustration of one embodiment of an apparatus for component recovery with a cage during a chemical application cycle. 
     
    
    
     DETAILED DESCRIPTION 
     Coated components are used in a variety of industries. Components may be coated with silicone coatings, polymers and other coatings. These coatings may serve different purposes such as protecting the component surface from damage or providing better surface chemistry for bonding. The components coated may be made of different materials. Metal components as well as composite components may have coatings. The components themselves may be made of polymers that are different from the coatings. Often times, coated components are expensive to replace and component refurbishment is used to reduce costs. Chemical cleaning and stripping is used to refurbish a component so that new coatings may be applied and the component returned to service. The chemicals used in the refurbishment process will largely depend on the type of coating and the type of component material. 
       FIG. 1  illustrates one embodiment of a component recovery system for refurbishing components. Component recovery system  10  includes fluid feed tanks  12   a - 12   c , refurbishment compartment  14 , and waste tanks  16   a - 16   c.  Fluid feed lines  18   a - 18   c  connect the fluid feed tanks  12   a - 12   c  to fluid line  20 . Each fluid feed line  18   a - 18   c  contains a valve  22 . Fluid line  20  includes fluid delivery pump  24 . Fluid delivery pump  24  delivers fluid from fluid feed tanks  12   a - 12   c  to fluid delivery line  28  and refurbishment compartment  14 . Fluid line  20  also includes valve  26 . Refurbishment compartment  14  may include multiple pieces to facilitate component insertion and removal. 
     Fluid feed tanks  12   a - 12   c  store the fluids used in the refurbishment process. Three fluid feed tanks  12   a - 12   c  are indicated in  FIG. 1  for illustrative purposes. More or fewer fluid feed tanks may be present depending on the number of fluids needed for refurbishment. The fluids contain the chemicals used to refurbish the components in component recovery system  10 . Examples of suitable fluids include strippers, solvents and rinse solutions. The fluids used in a component recovery system  10  will depend largely on the type of refurbishment to be performed (e.g., removing field contaminants, removing coatings, etc.). Suitable strippers include dichloromethane and other alkyl halides, aromatic hydrocarbons, kerosene and combinations thereof, such as Dynasolve 218, available from Dynaloy (Indianapolis, Ind.). Suitable solvents include kerosene, acetone and isopropanol. Suitable rinse solutions include acetone and water. One embodiment of component recovery system  10  may sequentially deliver an aromatic hydrocarbon/kerosene mixture, kerosene, acetone, and water to a component during refurbishment. Such an embodiment would require four fluid feed tanks  12 . 
     Because aggressive solvents may be used in component recovery system  10 , the system&#39;s tanks, lines, valves, and pumps must be constructed of materials that are resistant to aggressive solvents when used. Examples of suitable materials include stainless steel, Teflon, polyethylene and polypropylene. 
     Fluid feed lines  18   a - 18   c  allow fluid to flow from the fluid feed tanks  12   a - 12   c , respectively, to refurbishment compartment  14  via feed line  20  and fluid delivery line  28 . Each fluid feed line  18   a - 18   c  includes a valve  22   a - 22   c  configured to allow or prevent flow of the fluid in the feed tanks  12   a - 12   c,  respectively, into fluid line  20 . Suitable valves  22   a - 22   c  include solenoid valves. Fluid line  20  allows fluid to flow from fluid feed lines  18   a - 18   c  to fluid delivery line  28  and refurbishment compartment  14 . Fluid line  20  includes fluid delivery pump  24 . Fluid delivery pump  24  is configured to pump fluid. Fluid enters fluid line  20  from fluid feed lines  18   a - 18   c  and is pumped through fluid line  20  towards fluid delivery line  28  by fluid delivery pump  24 . Fluid line  20  also includes a valve  26  configured to allow or prevent flow of the fluid in fluid line  20  into fluid delivery line  28 . Valve  26  may be a solenoid valve. 
     Fluid delivery line  28  connects fluid line  20  to refurbishment compartment  14 . Fluid delivery line  28  provides one or more connections with refurbishment compartment  14 . Fluid delivery line  28  may be plumbed directly into refurbishment compartment  14  or may connect to additional lines within refurbishment compartment  14 . The embodiment illustrated in  FIG. 1  shows three connections between fluid delivery line  28  and refurbishment compartment  14  (upper left corner, upper central area and upper right corner). More or fewer connections may be present depending on the design of refurbishment compartment  14 . Fluid delivery line  28  supplies fluid to one or more delivery elements  30  located in the interior of refurbishment compartment  14 . Delivery element  30  directs fluid to one or more components inside refurbishment compartment  14 . 
     Delivery element  30  may be connected directly to fluid delivery line  28  within refurbishment compartment  14  or delivery element  30  may connect to fluid delivery line  28  via additional lines within refurbishment compartment  14 . Delivery element  30  direct fluids to the component to be cleaned inside refurbishment compartment  14 . Delivery element  30  is located within refurbishment compartment  14  and configured to direct fluid so that fluid may interact with the component surfaces. The embodiment illustrated in  FIG. 1  shows three delivery elements  30  connected to the line in the upper left portion of refurbishment compartment  14 , one delivery element in the upper central portion and three delivery elements in the upper right portion. Exemplary embodiments of component recovery system  10  may include delivery elements  30  positioned and configured to direct fluid optimally so that generally all component surfaces receive fluid. In some embodiments, delivery elements  30  may be adjustable so that optimal fluid delivery can be obtained during refurbishment for various components. Delivery elements  30  may include nozzles such as spray nozzles to atomize fluids or deliver fluids to a wide area within refurbishment compartment  14 . 
     Components to be refurbished are placed within refurbishment compartment  14 .  FIG. 1  shows a ring strut ring  48  (component) within refurbishment compartment  14  for illustrative purposes. Other components that require refurbishment may be placed within refurbishment compartment  14 . The dimension of refurbishment compartment  14  will vary depending on the size of the components to be refurbished. In an embodiment designed to refurbish a ring strut ring  48 , refurbishment compartment  14  may have a length of about 4.5 feet (1.4 meters), a width of about 1 foot (0.3 meters), and a height of about 4.5 feet (1.4 meters). The interior dimensions and geometries of refurbishment compartment  14  may be modified to accommodate the shapes of the components to be refurbished as well as the position of delivery elements  30  and drain  34 . 
     Refurbishment compartment  14  may include means for rotating or moving the components during refurbishment so that fluid directed by delivery element  30  contacts all component surfaces. One example of a rotating means is shaft  32 , which may be motor driven. Components may be mounted or fastened to shaft  32  so that the component is rotated during the refurbishment operation. Rotation allows multiple component surfaces to come into contact with the fluids directed to the component by delivery element  30 . In some embodiments, rotation may also allow component surfaces to submerge in fluid that has collected at the bottom of refurbishment compartment  14 . Submerging the component provides additional contact between component surfaces and refurbishment fluids. 
     Refurbishment compartment  14  also includes a drain  34 . Drain  34  is located in the lower portion of refurbishment compartment  14 . Refurbishment compartment  14  may be designed to direct fluid towards drain  34 . Drain  34  allows removal of fluid delivered to refurbishment compartment  14 . Drain  34  may include a valve that can be closed to allow fluid to collect in the bottom portion of refurbishment compartment  14  to provide fluid in which the component may be submerged as described above. Drain  34  connects to recirculation line  36 . 
     Recirculation line  36  connects refurbishment compartment drain  34  to fluid delivery line  28  and waste line  38 . Recirculation line  36  includes recirculation pump  40 . Recirculation pump  40  is configured to pump fluid. Recirculation pump  40  delivers fluid from drain  34  through recirculation line  36 , fluid delivery line  28  and waste line  38 . Recirculation line  36  also includes valve  42 . Valve  42  allows or prevents the flow of fluid to fluid delivery line  28  or waste line  38  depending on the process step. During recirculation, valve  42  allows fluid to flow through recirculation line  36  to fluid delivery line  28  but not to waste line  38 . During delivery to waste, valve  42  allows fluid to flow through recirculation line  36  to waste line  38  but not to fluid delivery line  28 . To provide both recirculation and waste routes, valve  42  may be a three-way valve. Alternatively, two valves may be used. In one embodiment of the present invention, valve  42  may be a three-way solenoid valve. 
     Waste line  38  is connected to waste outlet lines  44   a - 44   c.  Waste outlet lines  44   a - 44   c  connect to waste tanks  16   a - 16   c,  respectively. Each waste tank  16   a - 16   c  has a separate waste outlet line  44   a - 44   c.    FIG. 1  illustrates one embodiment of a component recovery system  10  with three waste tanks  16   a - 16   c.  Waste outlet lines  44   a - 44   c  connect waste line  38  to waste tanks  16   a - 16   c.  Each waste outlet line  44   a - 44   c  contains a valve  46   a - 46   c,  respectively. Valves  46   a - 46   c  allow or prevent flow of the fluid from waste line  38  to each waste tank  16   a - 16   c,  respectively. Suitable valves  46   a - 46   c  include solenoid valves. 
     The various operative steps of refurbishment using one embodiment of component recovery system  10  are demonstrated in  FIGS. 2A through 2D . In one such embodiment of the present invention, the refurbishment operation may be automated and controlled by one or more computers. 
       FIG. 2A  illustrates component recovery system  10  in fill mode. Valve  22   a  is in the open position while valves  22   b  and  22   c  are in the closed position. Fluid from fluid feed tank  12   a  flows through valve  22   a  in fluid feed line  18   a  and into fluid line  20 , while fluid from fluid feed tanks  12   b  and  12   c  are prevented from flowing through fluid feed lines  18   b  and  18   c , respectively. Fluid delivery pump  24  pumps the fluid through fluid line  20 . Valve  26  is in the open position and fluid flows through fluid line  20  to fluid delivery line  28 . Valve  42  is in the closed position so that fluid entering fluid delivery line  28  does not flow through recirculation line  36  to waste line  38  or the bottom portion of refurbishment compartment  14 . Fluid flows through fluid delivery line  28  to delivery elements  30 . Delivery elements  30  direct the flow of fluid onto the surfaces of the component(s) located in refurbishment compartment  14 , here ring strut ring  48 . If it is attached to a shaft  32 , the component may be rotated as fluid is directed towards its surfaces, thereby exposing as much of the components surface as possible to the fluid. As fluid flows into refurbishment compartment  14 , drain  34  is in the closed position and fluid accumulates in the bottom portion of refurbishment compartment  14 . Fluid accumulates in refurbishment compartment  14  until an adequate amount of fluid has been delivered to allow recirculation. In one embodiment, fluid may fill about ten percent of refurbishment compartment  14 . In other embodiments, fluid may generally fill refurbishment compartment  14  until the entire component is submerged in fluid. 
       FIG. 2B  illustrates component recovery system  10  in recirculation mode. Drain  34  is in the open position and allows fluid from refurbishment compartment  14  to empty and flow into recirculation line  36 . Recirculation pump  40  is activated to pump fluid through recirculation line  36 . Three-way valve  42  is opened so that fluid may flow from recirculation line  36  to fluid delivery line  28 . Three-way valve  42  is configured to allow fluid to flow to fluid delivery line  28  while fluid is prevented from flowing to waste line  38  and waste tanks  16 . Valve  26  is in the closed position. This prevents fluid from flowing back towards fluid line  20  and fluid feed tanks  12   a - 12   c.  Recirculated fluid thus flows from fluid delivery line  28  to delivery element  30  as described above in the fill mode operation. Fluid recirculates by flowing from drain  34  through recirculation line  36  and fluid delivery line  28  until it is once again directed toward the component in refurbishment compartment  14 . 
     Recirculation mode may be employed for a predetermined amount of time. Depending on the fluid and its function, recirculation times may vary. Generally, fluid is recirculated until its function is completed or continued recirculation becomes suboptimal. For example, when the fluid delivered to refurbishment compartment  14  is a stripper, the fluid may be recirculated until it ceases to optimally strip coating from the component surfaces. A stripper ceases to function optimally once additional coating is no longer solubilized by the stripper or once the coating and bonding compounds are removed. Once the stripper is saturated with the coating stripped from the component surfaces, continued recirculation may be undesirable. 
       FIG. 2C  illustrates component recovery system  10  in waste collection mode. Drain  34  is in the open position and allows fluid from refurbishment compartment  14  to empty and flow into recirculation line  36 . Recirculation pump  40  is activated to pump fluid through recirculation line  36 . Three-way valve  42  is opened so that fluid may flow from recirculation line  36  to waste line  38 . Three-way valve  42  is configured to allow fluid to flow to waste line  38  while fluid is prevented from flowing to fluid delivery line  28 . Valve  46   a  is in the open position and allows fluid to pass through waste outlet line  44   a.  Valves  46   b  and  46   c  are in the closed position to prevent fluid from entering waste tanks  16   b  and  16   c,  respectively. Waste fluid flows from recirculation line  36  to waste outlet line  44   a  and into waste tank  16   a.    
     Waste fluid is collected and stored in waste tanks  16   a - 16   c.  Once a waste tank  16  is full, the contained waste fluid may be removed from waste tank  16  and prepared for disposal or reuse within component recovery system  10  or for other uses. In one embodiment, waste tanks  16   a - 16   c  may also serve as disposal tanks so that waste tanks  16   a - 16   c  may be removed from component recovery system  10 , sent out for disposal, and new waste tanks  16   a - 16   c  may be added to component recovery system  10  to replace the tank sent for disposal. 
     In one embodiment of component recovery system  10 , fluid waste collected in waste tanks  16   a - 16   c  may be reused by component recovery system  10 . For example, waste stripper that is not saturated with the coating removed from the component(s) may be reused. Such waste fluid may be transferred to one of fluid feed tanks  12   a - 12   c  after it has been collected in one of waste tanks  16   a - 16   c.  Waste tanks  16   a - 16   c  and fluid feed tanks  12   a - 12   c  may be interchangeable so that waste tanks  16   a - 16   c  may be disconnected from waste outlet lines  44   a - 44   c  and connected to fluid feed lines  18   a - 18   c  for reuse. 
       FIG. 2D  illustrates component recovery system  10  in rinse mode. Rinse mode provides for a single pass of fluid to the component(s) in refurbishment compartment  14 . Valve  22   a  is in the open position while valves  22   b  and  22   c  are in the closed position. Fluid from fluid feed tank  12   a  flows through valve  22   a  in fluid feed line  18   a  and into fluid line  20 , while fluid from fluid feed tanks  12   b  and  12   c  are prevented from flowing through fluid feed lines  18   b  and  18   c,  respectively. Fluid delivery pump  24  pumps the fluid through fluid line  20 . Valve  26  is in the open position and fluid flows through fluid line  20  to fluid delivery line  28 . Valve  42  is in a position so that fluid entering fluid delivery line  28  does not flow through recirculation line  36  to waste line  38  or the bottom portion of refurbishment compartment  14 . Fluid flows through fluid delivery line  28  to delivery elements  30 . Delivery elements  30  direct the flow of fluid onto the surfaces of the component(s) located in refurbishment compartment  14 . Fluid flows into refurbishment compartment  14  at delivery elements  30  and exits through drain  34 . Drain  34  is in the open position and allows fluid from refurbishment compartment  14  to empty and flow into recirculation line  36 . Recirculation pump  40  is activated to pump fluid through recirculation line  36 . Three-way valve  42  is positioned so that fluid may flow from recirculation line  36  to waste line  38 . Valve  46   a  is in the open position and allows fluid to pass through waste outlet line  44   a  and into waste tank  16   a.  Valves  46   b  and  46   c  are in the closed position to prevent fluid from entering waste tanks  16   b  and  16   c,  respectively. 
     Alternative embodiments of component recovery system  10  may include one or more baskets  50  or cages  52  (illustrated in  FIG. 3A and 3B , respectively) within refurbishment compartment  14 . Basket  50  may be placed merely on the bottom inner surface of refurbishment compartment  14  or on a support  52  within refurbishment compartment  14 . Basket  50  allows for multiple components to be easily inserted and removed from refurbishment compartment  14 . Multiple baskets  50  arranged within refurbishment compartment  14  may provide for refurbishment of several components at once. 
       FIG. 3A  illustrates component recovery system  10 A in fill mode. Component recovery system  10 A is generally similar to component recovery system  10 , except that it includes basket  50  within refurbishment compartment  14 . Basket  50  may hold components to be refurbished and position them so that fluid directed by delivery elements  30  comes in contact with component surfaces. Basket  50  may be a stainless steel basket with a plurality of openings to allow fluid to pass from the outside of the basket to the inside of the basket. Basket  50  may have an open side so that components may be easily positioned inside and removed from basket  50 . 
     Alternatively, basket  50  may be replaced by cage  54 , as illustrated in  FIG. 3B .  FIG. 3B  illustrates component recovery system  10 B in waste collection mode. Cage  54  may hold components to be refurbished and position them so that fluid directed by delivery elements  30  comes in contact with component surfaces during fill, recirculation and rinse modes. Additionally, cage  54  may be fastened to a shaft  32  and rotated. Cages  54  rotated on shaft  32  may provide multiple orientations of component surfaces with respect to delivery element  30 . This may allow multiple component surfaces to come into contact with the fluids directed to the component by delivery element  30 . Rotation may provide for increased fluid contact with component surfaces during refurbishment. As with baskets  50 , multiple cages  54  may be arranged within refurbishment compartment  14 . Multiple cages  54  may also be mounted or fastened to shaft  32 . Cage  54  may be a stainless steel cage with a plurality of openings to allow fluid to pass from the outside of the cage to the inside of the cage. 
     The embodiments described above provide a system and method for component recovery with several advantages over the prior art. Refurbishment of a component can be performed while reducing the amounts of chemicals needed. A smaller amount of chemicals translates to cost savings in the purchasing and disposal of the chemicals. The process can be automated to reduce workers&#39; exposure to harsh or toxic chemicals. Embodiments of the component recovery system may also reduce space requirements needed for refurbishment. 
     Although the present invention has been described with reference to exemplary embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.