Patent Publication Number: US-9415404-B2

Title: High viscosity fluid dispensing system

Description:
BACKGROUND INFORMATION 
     1. Field: 
     The present disclosure relates generally to dispensing fluids and, in particular, to dispensing high viscosity fluids. Still more particularly, the present disclosure relates to a method and apparatus for dispensing a high viscosity fluid, such as sealant, onto a surface from a desired distance away from the surface in a desired spray pattern. 
     2. Background: 
     Assembly operations oftentimes require applying sealant to various locations. For example, without limitation, during the assembly of an aircraft, sealant may be applied to joints and fastener elements to seal faying surfaces, protect components, prevent leakages, and/or reduce undesired electromagnetic effects. As one illustrative example, sealant may be applied over a fastener element installed at an outer surface of an object to prevent any fluid from escaping the object and/or entering the object. 
     Oftentimes, sealant may be manually dispensed from a sealant cartridge and applied. However, the manual dispensing and application of the sealant may be more time-consuming and/or difficult than desired. In some cases, a sealant cartridge may be mounted onto a robot that is used to dispense the sealant from the sealant cartridge. However, these different processes may require more frequent replacements of sealant cartridges than desired. Further, these types of processes may require more cleanup of spills and/or excess sealant. 
     Additionally, some currently available methods for dispensing sealant may be unable to dispense sealant in a desired pattern at desired distances. In particular, the accuracy of the pattern formed by the sealant dispensed from these currently available methods for dispensing sealant may decrease as the distance between the sealant dispensing system and the surface onto which the sealant is being applied increases. 
     Working with sealant using some currently available methods for dispensing sealant may be more difficult than desired, depending on the viscosity of the sealant. Typically, sealants having viscosities above, for example, without limitation, about 10,0000 centiPoise (cP), may be more difficult to dispense in a desired pattern with a desired level of accuracy than desired. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues. 
     SUMMARY 
     In one illustrative embodiment, an apparatus may comprise a housing comprising a chamber, a dispensing device, and a nozzle system. The housing may be configured to receive a fluid. The housing may be configured to increase a tendency of the fluid to flow within the chamber. The dispensing device may be configured to move the fluid in the chamber towards an exit of the chamber such that the fluid is dispensed through the exit of the chamber. The nozzle system may be configured to control an exit pressure of the fluid that is dispensed through the nozzle system. 
     In another illustrative embodiment, a fluid dispensing system may comprise a housing, a dispensing system, a nozzle system, a fluid transfer system, a tool system associated with the housing, an air protection device associated with the tool system, an attachment feature, and a controller. The housing may comprise an outer surface, an inner surface, and a heating system. The inner surface may be configured to form a chamber. The inner surface may be comprised of a friction-reducing material selected from one of polytetrafluoroethylene, a nanostructured non-stick material, and a nanostructured ceramic material. The friction-reducing material may be configured to reduce friction generated between the fluid and the inner surface such that a tendency of the fluid to flow through the chamber is increased. The heating system may be configured to heat the fluid within the chamber to reduce a viscosity of the fluid in the chamber such that the tendency of the fluid to flow through the chamber is increased. The heating system may comprise a plurality of heating coils located between the inner surface of the housing and the outer surface of the housing. The dispensing device may be configured to move the fluid in the chamber towards an exit of the chamber such that the fluid is dispensed through the exit of the chamber. The fluid dispensing system may comprise a piston configured to move within the chamber and a plurality of stoppers. At least one of the plurality of stoppers may be configured to limit movement of the piston within the chamber. The nozzle system may comprise a nozzle and a nozzle screen positioned at the exit of the chamber. The nozzle screen may comprise a plurality of holes having a plurality of sizes selected to control an exit pressure of the fluid across the nozzle screen as the fluid exits the nozzle screen such that the fluid is dispensed towards a surface in a desired spray pattern with a desired velocity. Each of the plurality of holes may have a tapered shape. The fluid transfer system may be configured to transfer the fluid from a fluid source to the chamber. The tool system may be configured to hold a number of tools for use in performing fluid dispensing operations. The air protection device may be configured to shield the number of tools from fluid spatter. The attachment feature may be configured for association with the housing. The attachment feature may be further configured for use in attaching one of a drip tray and a drip bucket to the housing to catch any dripping of the fluid as the fluid exits the chamber. The controller may be configured to control the heating system and the dispensing device. 
     In yet another illustrative embodiment, a method for dispensing a fluid may be provided. The fluid may be received within a chamber formed by an inner surface of a housing. A tendency of the fluid to flow through the chamber may be increased. The fluid may be moved through the chamber towards an exit of the chamber using a dispensing device such that the fluid is dispensed through a nozzle system at the exit of the chamber. An exit pressure of the fluid that is dispensed through the nozzle system may be controlled. 
     In still yet another illustrative embodiment, a method for dispensing a fluid is provided. The fluid from a fluid source may be transferred to a chamber using a fluid transfer system. The fluid within the chamber may be received. The chamber may be formed by an inner surface of a housing. The inner surface may be comprised of a friction-reducing material selected from one of polytetrafluoroethylene, a nanostructured non-stick material, and a nanostructured ceramic material. Friction generated between the fluid and the inner surface of the chamber as the fluid moves through the chamber may be reduced by the friction-reducing material such that a tendency of the fluid to flow through the chamber is increased. The fluid may be heated within the chamber using a heating system comprising a plurality of heating coils located between the inner surface of the housing and an outer surface of the housing to reduce a viscosity of the fluid in the chamber such that tendency of the fluid to flow through the chamber is increased. The fluid in the chamber may be moved towards an exit of the chamber using a dispensing device such that the fluid is dispensed through a nozzle screen positioned at the exit of the chamber. The fluid may be dispensed through a plurality of holes in the nozzle screen towards a surface. An exit pressure of the fluid across the nozzle screen may be controlled as the fluid is dispensed through the plurality of holes in the nozzle screen. The plurality of holes may have a plurality of sizes selected such that the fluid exits the nozzle screen towards the surface in a desired spray pattern with a desired velocity. A number of tools housed in a tool housing associated with the housing for use in performing fluid dispensing operations using an air protection device may be shielded. 
     The features and functions can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims. The illustrative embodiments, however, as well as a preferred mode of use, further objectives and features thereof, will best be understood by reference to the following detailed description of an illustrative embodiment of the present disclosure when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an illustration of a manufacturing environment in the form of a block diagram in accordance with an illustrative embodiment; 
         FIG. 2  is an illustration of a nozzle screen in the form of a block diagram in accordance with an illustrative embodiment; 
         FIG. 3  is an illustration of a fluid dispensing system in accordance with an illustrative embodiment; 
         FIG. 4  is an illustration of a cross-sectional view of a fluid dispensing system in accordance with an illustrative embodiment; 
         FIG. 5  is an illustration of a tool system and an air protection device in accordance with an illustrative embodiment; 
         FIG. 6  is another illustration of a nozzle screen in accordance with an illustrative embodiment; 
         FIG. 7  is an illustration of a hole in accordance with an illustrative embodiment; 
         FIG. 8  is yet another illustration of a nozzle screen in accordance with an illustrative embodiment; 
         FIG. 9  is an illustration of a process for dispensing fluid in the form of a flowchart in accordance with an illustrative embodiment; 
         FIG. 10  is an illustration of a process for dispensing fluid in the form of a flowchart in accordance with an illustrative embodiment; 
         FIG. 11  is an illustration of an aircraft manufacturing and service method in the form of a flowchart in accordance with an illustrative embodiment; and 
         FIG. 12  is an illustration of an aircraft in the form of a block diagram in which an illustrative embodiment may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     The illustrative embodiments recognize and take into account different considerations. For example, the illustrative embodiments recognize and take into account that it may be desirable to have a method and apparatus for dispensing sealant that allows the viscosity of the fluid to be controlled such that the mobility of the sealant may be increased. In this manner, the sealant may be dispensed more easily. Further, the illustrative embodiments recognize and take into account that it may be desirable to have an apparatus that allows the sealant to be pressurized as the sealant is dispensed such that the sealant may be dispensed in a desired pattern with a desired velocity from a desired distance. 
     Thus, the illustrative embodiments provide a method and apparatus for applying a fluid having a high viscosity onto a surface. In one illustrative embodiment, an apparatus may comprise a housing, a heating system, and a dispensing device. The housing may comprise a chamber configured to receive a fluid. The chamber may have an inner surface comprised of a friction-reducing material. The heating system may be configured to heat the fluid within the chamber to reduce viscosity of the fluid in the chamber to increase a mobility of the fluid within the chamber. The dispensing device may be configured to move the fluid in the chamber towards an exit of the chamber such that the fluid may be dispensed through the exit of the chamber. 
     Referring now to the figures and, in particular, with reference to  FIG. 1 , an illustration of a manufacturing environment is depicted in the form of a block diagram in accordance with an illustrative embodiment. In this illustrative example, manufacturing environment  100  may be an example of an environment in which manufacturing operations may be performed. These manufacturing operations may include, for example, without limitation, fluid dispensing operations. 
     Within manufacturing environment  100 , fluid dispensing system  102  may be used to dispense fluid  104  onto surface  106  of object  108 . Object  108  may take a number of different forms. Depending on the implementation, object  108  may be comprised of one or more components. For example, without limitation, object  108  may take the form of a fuselage, a wing, a spar, a fastener element, a panel, a door, a joint, a hinged object, a box, a vehicle, a desk, a chair, a flap, an aileron, a ship, a spacecraft, or some other type of object. 
     Fluid  104  may take the form of sealant  105  in this illustrative example. Further, fluid  104  may have viscosity  110 . In this illustrative example, viscosity  110  may be high. In particular, viscosity  110  may be above selected threshold  112  when fluid  104  is at a baseline temperature. This baseline temperature may be, for example, room temperature, ambient temperature, or some other reference temperature. 
     Selected threshold  112  may be, for example, without limitation, about 10,000 centiPoise (cP). In other cases, selected threshold  112  may be about 25,000 centiPoise or 100,000 centiPoise. In yet other examples, selected threshold  112  may be about 500,000 centiPoise. 
     As depicted, fluid dispensing system  102  may include housing  114 , fluid transfer system  116 , heating system  118 , dispensing device  120 , and nozzle system  121 . Housing  114  may have outer surface  124  and inner surface  126 . Inner surface  126  of housing  114  may form chamber  115  configured to hold fluid  104 . Nozzle system  121  may be used to dispense fluid  104 . 
     Chamber  115  may extend through both housing  114  and nozzle  122  in nozzle system  121 . In one illustrative example, nozzle  122  may be a separate component attached to housing  114 . In other illustrative examples, nozzle  122  may be formed by a portion of housing  114 . Nozzle  122  may be the component through which fluid  104  is dispensed and applied to surface  106 . Nozzle  122  may have conical shape  123  configured to increase the velocity with which fluid  104  is dispensed. In particular, conical shape  123  of nozzle  122  may allow fluid  104  to converge and pick up velocity as fluid  104  flows out of nozzle  122 . 
     In this illustrative example, inner surface  126  of housing  114  may be the portion of housing  114  that contacts fluid  104  while fluid  104  is within chamber  115 . Inner surface  126  may be comprised of friction-reducing material  128 . Friction-reducing material  128  may be selected such that friction between fluid  104  and inner surface  126  is reduced when fluid  104  is moving, or flowing, within chamber  115 . 
     In one illustrative example, friction-reducing material  128  may comprise polytetrafluoroethylene (PTFE)  130 . Of course, in other illustrative example, friction-reducing material  128  may be comprised of a nanostructured ceramic material, a nanostructured non-stick material, or some other type of material. 
     As depicted, fluid transfer system  116  may transfer fluid  104  from fluid source  132  into chamber  115 . Fluid source  132  may be configured to store and hold fluid  104 . When fluid  104  takes the form of sealant  105 , fluid source  132  may take the form of sealant tank  133 . 
     In this illustrative example, heating device  135  may be associated with fluid source  132 . Heating device  135  may be used to heat fluid  104  held within fluid source  132 . In particular, fluid  104  may be heated to a temperature based on viscosity  110 . 
     For example, without limitation, viscosity  110  of fluid  104  may be at a level that reduces the mobility of fluid  104 . As used herein, the “mobility” of fluid  104  may mean the tendency of fluid  104  to flow. As viscosity  110  of fluid  104  increases, the mobility of fluid  104  may decrease. Heating device  135  may be used to heat fluid  104  to reduce viscosity  110  of fluid  104  and thereby, increase the mobility of fluid  104 . In other words, the tendency of fluid  104  to flow through chamber  115  may be increased using heating device  135 . 
     In one illustrative example, heating device  135  may be considered a part of heating system  118 . In other illustrative examples, heating device  135  may be considered separate from heating system  118 . Heating device  135  may take a number of different forms. For example, without limitation, heating device  135  may take the form of a plurality of heating coils, a microwave oven, or some other type of heating device. 
     Fluid transfer system  116  may include at least one of number of transfer elements  134 , viscometer  136 , or valve  138 . As used herein, the phrase “at least one of,” when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, “at least one of” means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. 
     For example, “at least one of item A, item B, and item C” may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, “at least one of item A, item B, and item C” may mean, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination. 
     Further, as used herein, a “number of” items may be one or more items. In this manner, number of transfer elements  134  may include one or more transfer elements. A transfer element in number of transfer elements  134  may take the form of a hose, a tube, a coil, a hollow elongate member, or some other type of element configured to allow fluid  104  to flow. Number of transfer elements  134  may be used to transfer fluid  104  from fluid source  132  into chamber  115 . 
     Valve  138  may be used to control the flow of fluid  104  into chamber  115 . In this manner, valve  138  may also be referred to as a flow control valve. Viscometer  136  may be used to measure viscosity  110  of fluid  104  as fluid  104  leaves fluid source  132  and is transferred into chamber  115 . Heating system  118  may be used to ensure that a desired viscosity for fluid  104  is maintained within chamber  115 . 
     In one illustrative example, heating system  118  may take the form of plurality of heating coils  140 . Plurality of heating coils  140  may be used to heat fluid  104  within chamber  115  to ensure that viscosity  110  of fluid  104  is at the desired level to ensure the desired mobility of fluid  104  within chamber  115 . 
     Plurality of heating coils  140  may be located within open space  139  between outer surface  124  and inner surface  126  of housing  114  in this example. Outer surface  124  may protect plurality of heating coils  140  from exposure to environmental elements and/or protect an operator from contacting plurality of heating coils  140 . Outer surface  124  may also have insulation layer  125  wrapped along the length of outer surface  124  to shield the operator from contacting outer surface  124  that has been heated and to help maintain the temperature of fluid  104 . Inner surface  126  separates plurality of heating coils  140  from fluid  104  such that the heating of fluid  104  may be performed in a more controlled manner. 
     In this illustrative example, dispensing device  120  may be used to move fluid  104  through chamber  115  and out of chamber  115 . As depicted, dispensing device  120  may include actuation system  141 . Actuation system  141  may be located at or near first end  143  of chamber  115 . Actuation system  141  may be configured to move fluid  104  from first end  143  of chamber  115  towards second end  145  of chamber  115 . 
     Actuation system  141  may include, for example, without limitation, any number of actuators and/or other devices. In one illustrative example, actuation system  141  may include piston  142 , plurality of stoppers  144 , spring  146 , and compressed air regulator  148 . 
     Piston  142  may be configured to move fluid  104  towards second end  145  of chamber  115 . Piston  142  may be moved using compressed air generated by compressed air regulator  148 . Compressed air regulator  148  may be configured to pump air  147  that is compressed into inlet  149  associated with piston  142 . Air  147  may be compressed according to desired specifications. This compressed air may power piston  142  and cause piston  142  to move in a direction towards second end  145 . As piston  142  moves towards second end  145 , air  147  may be discharged through number of outlets  151  associated with piston  142 . Number of outlets  151  may allow air  147  to exit housing  114 . 
     As used herein, when one component is “associated” with another component, the association is a physical association in the depicted examples. For example, a first component, such as inlet  149 , may be considered to be associated with a second component, such as piston  142 , by being secured to the second component, bonded to the second component, mounted to the second component, welded to the second component, fastened to the second component, and/or connected to the second component in some other suitable manner. The first component also may be connected to the second component using a third component. Further, the first component may be considered to be associated with the second component by being formed as part of and/or as an extension of the second component. 
     Once air  147  has been discharged through number of outlets  151 , spring  146  may be used to allow piston  142  to move back towards first end  143 . In other words, spring  146  may allow piston  142  to return to the starting position of piston  142 . 
     Plurality of stoppers  144  may be used to stop the movement of piston  142 . In one illustrative, plurality of stoppers  144  may include one stopper to limit the movement of piston  142  in the direction towards second end  145  and another stopper to limit the movement of piston  142  in the direction towards first end  143 . 
     In this illustrative example, the movement of piston  142  in the direction towards second end  145  may move fluid  104  towards exit  150  of chamber  115  at second end  145  of chamber  115  within nozzle  122 . In this manner, exit  150  of chamber  115  may also be the exit of nozzle  122 . In particular, fluid  104  may be moved such that fluid  104  is dispensed through exit  150  of chamber  115 . 
     Nozzle system  121  may also include nozzle screen  152 . As depicted, nozzle screen  152  may be positioned at exit  150  of chamber  115 . Nozzle screen  152  may be used to modify the flow of fluid  104  out of chamber  115  at exit  150 . Nozzle screen  152  may be associated with nozzle  122 . In this manner, nozzle screen  152  may be considered part of nozzle  122 , attached to nozzle  122 , or associated with nozzle  122  in some other manner. Nozzle screen  152  may be used to increase the exit pressure of fluid  104  dispensed out of nozzle  122  such that fluid  104  is dispensed in a spraying manner. 
     In some illustrative examples, nozzle  122  may be used to increase the exit pressure of fluid  104  dispensed out of nozzle  122 , while nozzle screen  152  may be used to screen, or filter, fluid  104  being dispensed through nozzle screen  152 . For example, without limitation, nozzle screen  152  may be used to filter out any lumps in fluid  104  such that fluid  104  dispensed through nozzle screen  152  has a desired consistency. In this manner, nozzle  122  and/or nozzle screen  152  may be used to control the exit pressure of fluid  104  being dispensed through nozzle system  121 . 
     In this illustrative example, exit structure  154  may also be associated with nozzle  122 . Exit structure  154  may also be positioned at second end  145  of chamber  115  at exit  150 . Exit structure  154  may be used to further control the flow of fluid  104  out of nozzle  122 . In one illustrative example, exit structure  154  may take the form of a conical rim. In some cases, the size and/or shape of exit structure  154  may be adjustable such that the flow of fluid  104  out of nozzle  122  may be adjusted as needed. 
     Additionally, fluid dispensing system  102  may also include tool system  156 . Tool system  156  may include number of tools  158  and tool housing  160 . Number of tools  158  may be housed within tool housing  160 . Number of tools  158  may be configured for use in performing fluid dispensing operations. 
     For example, without limitation, number of tools  158  may include at least one of an imaging device, a light source, a number of sensor devices, or some other type of device. The imaging device may be used to monitor the fluid dispensing operations and assist in the positioning of fluid dispensing system  102 . The light source may be needed for dispensing fluid  104  in areas of low visibility and/or in enclosed spaces. The sensor devices may be used for measuring the thickness of fluid  104  being dispensed for quality control purposes. In this manner, any number of devices may be included within tool system  156  for use in performing fluid dispensing operations. 
     In this illustrative example, air protection device  162  may be associated with tool housing  160 . At least one of number of tools  158  may be exposed to the environment around fluid dispensing system  102  within tool housing  160 . Tool housing  160  may need to be at least partially open such that number of tools  158  may have a line of sight towards fluid  104  being dispensed through nozzle  122  and/or surface  106 . 
     Air protection device  162  may be configured to create a curtain of air that shields number of tools  158  from fluid spatter and/or the environment around fluid dispensing system  102 . This curtain of air still allows number of tools  158  to maintain visibility of fluid  104  being dispensed and/or surface  106  as needed. 
     In one illustrative example, fluid dispensing system  102  may also have attachment feature  164 . In particular, attachment feature  164  may be configured for association with housing  114 . Further, attachment feature  164  may be configured for use in attaching one of a drip tray (not shown), a drip bucket (not shown), or some other type of object (not shown) that can catch any dripping of fluid  104  as fluid  104  is dispensed through nozzle  122 . In one illustrative example, attachment feature  164  may take the form of a hook, a fastener element, or some other type of attachment feature. 
     As depicted, controller  166  may be used to control at least one of heating system  118 , actuation system  141 , valve  138 , or some other component within fluid dispensing system  102 . In particular, controller  166  may be configured to control compressed air regulator  148  within actuation system  141 . Controller  166  may be considered part of or separate from fluid dispensing system  102 , depending on the implementation. 
     In some cases, controller  166  may be configured to receive data from viscometer  136 . Controller  166  may use this data to control heating system  118 , heating device  135 , and/or valve  138 . In particular, controller  166  may control the temperature to which heating system  118  is used to heat fluid  104  within chamber  115  and/or the temperature to which heating device  135  is used to heat fluid  104  within fluid source  132  based on viscosity  110  of fluid  104  as measured by viscometer  136 . 
     In this manner, fluid dispensing system  102  may allow fluid  104  having viscosity  110  above selected threshold  112  to be dispensed with ease. Viscosity  110  of fluid  104 , and thus the mobility of fluid  104 , may be controlled using heating system  118  and heating device  135 . Further, the friction generated between fluid  104  and inner surface  126  of chamber  115  may be reduced by friction-reducing material  128 . Thus, the dispensing of fluid  104  may be made easier. 
     With reference now to  FIG. 2 , an illustration of nozzle screen  152  from  FIG. 1  is depicted in greater detail in the form of a block diagram in accordance with an illustrative embodiment. In this illustrative example, nozzle screen  152  may have first side  202  and second side  204 . 
     First side  202  may be configured to face exit  150  in  FIG. 1 . Second side  204  may be configured to face away from exit  150  and nozzle  122 . In particular, second side  204  may be configured to face surface  106  in  FIG. 1  when fluid dispensing system  102  in  FIG. 1  is positioned relative to surface  106 . In this manner, fluid  104  may enter nozzle screen  152  through first side  202  and exit nozzle screen  152  through second side  204 . 
     Further, nozzle screen  152  may have plurality of holes  206  configured to extend from first side  202  to second side  204 . In particular, each of plurality of holes  206  may form a channel through nozzle screen  152  that is open at both first side  202  and second side  204 . 
     Plurality of holes  206  may have plurality of sizes  207 . Some of plurality of holes  206  may have one size, while other holes in plurality of holes  206  may have different sizes. 
     Hole  208  may be an example of one of plurality of holes  206 . As depicted, hole  208  may have tapered shape  210 . With tapered shape  210 , diameter  212  of hole  208  changes. In particular, diameter  212  of hole  208  may be first diameter  214  at first side  202  and second diameter  216  at second side  204 . First diameter  214  may be greater than second diameter  216  in this illustrative example. 
     The tapered shape of each of plurality of holes  206  may be sized such that the exit pressure of fluid  104  from  FIG. 1  dispensed through nozzle screen  152  may be increased as fluid  104  passes through nozzle screen  152 . In some cases, plurality of holes  206  may be considered a plurality of small nozzles working in parallel such that fluid  104  is “sprayed out” through nozzle screen  152  in a plurality of streams as compared to a single stream. This type of configuration for nozzle screen  152  may allow fluid  104  to be sprayed out in a controlled manner from a greater distance from surface  106  in  FIG. 1  as compared to when each of plurality of holes  206  has a substantially constant diameter between first side  202  and second side  204  of nozzle screen  152 . 
     Nozzle screen  152  may take a number of different shapes, depending on the implementation. For example, without limitation, nozzle screen  152  may have a circular shape, a square shape, a rectangular shape, a triangular shape, an elliptical shape, an octagonal shape, or some other type of shape. The shape of nozzle screen  152  and the arrangement of plurality of holes  206  may be selected such that fluid  104  sprays out of nozzle screen  152  in desired spray pattern  220  with desired velocity  221 . 
     Further, the cross-sectional shape of each of plurality of holes  206  may be selected such that fluid  104  is sprayed out in desired spray pattern  220  with desired velocity  221 . For example, without limitation, the cross-sectional shape of hole  208  may be selected from one of a circular shape, a square shape, a rectangular shape, a triangular shape, an elliptical shape, an octagonal shape, or some other type of shape. Spraying fluid  104  with desired velocity  221  may ensure that fluid  104  reaches surface  106  from a selected distance away from surface  106 . 
     Additionally, in this illustrative example, nozzle screen  152  may be comprised of friction-reducing material  128 . In particular, first side  202 , second side  204 , and the inner surfaces of plurality of holes  206  may be comprised of friction-reducing material  128  such that all portions of nozzle screen  152  that may come into contact with fluid  104  may be comprised of friction-reducing material  128 . In this manner, friction between fluid  104  and nozzle screen  152  may be reduced as fluid  104  passes through nozzle screen  152 . 
     The illustrations of manufacturing environment  100 , and in particular, fluid dispensing system  102  in  FIG. 1  and nozzle screen  152  in  FIG. 2  are not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the ones illustrated may be used. Some components may be optional. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment. 
     Although actuation system  141  is described as comprising piston  142 , spring  146 , and compressed air regulator  148 , actuation system  141  may be implemented in some other manner. For example, without limitation, actuation system  141  may be implemented using a motor-driven roller screw, an electromagnetic slider, and/or other types of devices. 
     In other illustrative examples, attachment feature  164  may be optional. In some cases, tool system  156  may be optional. 
     With reference now to  FIG. 3 , an illustration of a fluid dispensing system is depicted in accordance with an illustrative embodiment. In this illustrative example, fluid dispensing system  300  may be an example of one implementation for fluid dispensing system  102  in  FIG. 1 . As depicted, fluid dispensing system  300  may include housing  302 , fluid transfer system  304 , handle  306 , handle  308 , and actuation system  310 . 
     Housing  302 , fluid transfer system  304 , and actuation system  310  may be examples of implementations for housing  114 , fluid transfer system  116 , and actuation system  141 , respectively, in  FIG. 1 . Housing  302  may include nozzle  312  in this example. Nozzle  312  may be an example of one implementation for nozzle  122  in  FIG. 1 . Handle  306  and handle  308  may be used by an operator to handle and operate fluid dispensing system  300 . 
     As depicted, fluid transfer system  116  may include hose  305  and other components (not shown in this view). Hose  305  may be an example of one implementation for a transfer element in number of transfer elements  134  in  FIG. 1 . Hose  305  may be used to transfer fluid (not shown) from a fluid source (not shown) into a chamber (not shown) within housing  302 . 
     Actuation system  310  may include inlet  313 , compressed air regulator  314 , and piston  315 . Inlet  313 , compressed air regulator  314 , and piston  315  may be examples of implementations for inlet  149 , compressed air regulator  148 , and piston  142 , respectively, in  FIG. 1 . Further, actuation system  310  may also include outlet  317  and outlet  319 . Outlet  317  and outlet  319  may be an example of one implementation for number of outlets  151  in  FIG. 1 . In this illustrative example, power line  316  may be used to provide electrical power to fluid dispensing system  300 . Of course, in other illustrative examples, fluid dispensing system  300  may be powered using pneumatic power and/or some other type of power. 
     In this illustrative example, exit  318  of nozzle  312  may be an example of one implementation for exit  150  in  FIG. 1 . Exit  318  may also be the exit of the chamber (not shown) that passes through housing  302  and nozzle  312 . Nozzle screen  320  may be positioned at exit  318  such that fluid being dispensed through nozzle  312  passes through nozzle screen  320 . Nozzle screen  320  may be an example of one implementation for nozzle screen  152  in  FIG. 1 . 
     Further, exit structure  322  may be attached to nozzle  312 . Exit structure  322  may be an example of one implementation for exit structure  154  in  FIG. 1 . Exit structure  322  may be used to further control the flow of fluid out of nozzle  312 . 
     Tool system  324  may be attached to housing  302  in this illustrative example. Tool system  324  may be an example of one implementation for tool system  156  in  FIG. 1 . Further, as depicted, air protection device  326  may be associated with tool system  324 . Air protection device  326  may receive air through air line  328 . Tool system  324  and air protection device  326  may be described in greater detail in  FIG. 5  below. 
     In this illustrative example, fluid dispensing system  300  may also include drip tray hook  330 . Drip tray hook  330  may be used to attach a drip tray (not shown) to fluid dispensing system  300 . This drip tray may be used to catch any dripping of fluid that is dispensed from nozzle  312 . In other examples, a drip bucket (not shown) may be hung from drip tray hook  330 . Drip tray hook  330  may be an example of one implementation for attachment feature  164  in  FIG. 1 . 
     Turning now to  FIG. 4 , an illustration of a cross-sectional view of fluid dispensing system  300  from  FIG. 3  is depicted in accordance with an illustrative embodiment. In this illustrative example, a cross-sectional view of fluid dispensing system  300  has been taken with respect to lines  4 - 4  from  FIG. 3 . 
     As depicted, fluid dispensing system  300  may be used to dispense fluid  402  and apply fluid  402  held in fluid tank  404  onto surface  400 . Fluid  402  and fluid tank  404  may be examples of implementations for fluid  104  and fluid source  132 , respectively, in  FIG. 1 . 
     In this illustrative example, fluid tank  404  may be heated. In other words, fluid tank  404  may be configured to heat fluid  402  to reduce the viscosity of fluid  402  to a desired viscosity. In some cases, fluid tank  404  may also be equipped with mixers (not shown) for use in mixing and preparing a multi-component fluid  402  before dispensing. In other words, fluid  402  may be comprised of a single homogeneous substance or a combination of various substances that are mixed within fluid tank  404 . Thermometer  406  may be used to monitor the temperature of fluid  402  within fluid tank  404 . 
     Fluid transfer system  304  may transfer fluid  402  from fluid tank  404  into chamber  418  within housing  302 . Fluid transfer system  304  may include hose  305 , viscometer  408 , valve  410 , and pump  411 . Viscometer  408  and valve  410  may be examples of implementations for viscometer  136  and valve  138 , respectively, in  FIG. 1 . 
     Viscometer  408  may be associated with hose  305  and configured to measure the viscosity of fluid  402 . Valve  410  may be configured to control the flow of fluid  402  into chamber  418 . Pump  411  may be used to pump fluid  402  from fluid tank  404  into hose  305  and towards valve  410 . Fluid  402  may flow from fluid tank  404  into chamber  418  in the direction of arrow  412 . 
     As depicted, housing  302  may have outer surface  414  and inner surface  416 . Chamber  418  may be formed by inner surface  416  of housing  302 . Outer surface  414 , inner surface  416 , and chamber  418  may be examples of implementations for outer surface  124 , inner surface  126 , and chamber  115 , respectively, in  FIG. 1 . 
     In this illustrative example, actuation system  310  may include piston  315 , stopper  422 , stopper  424 , spring  426 , inlet  313 , and compressed air regulator  314 . Stopper  422  and stopper  424  may be an example of one implementation for plurality of stoppers  144  in  FIG. 1 . 
     Controller  420  may be used to control compressed air regulator  314 , and thereby, the motion of piston  315  in synchronization with pump  411  to deliver fluid  402 . Controller  420  may be an example of one implementation for controller  166  in  FIG. 1 . Compressed air regulator  314  may regulate the sending of compressed air into inlet  313  associated with piston  315 . This compressed air may power piston  315  and cause piston  315  to move away from an initial position in the direction of arrow  430 . Stopper  422  may limit the movement of piston  315  such that piston  315  may not be moved past stopper  422  in the direction of arrow  430 . 
     The compressed air may be discharged through outlet  317  and outlet  319 . When the compressed air is discharged, spring  426  may cause piston  315  to return to or near the initial position for piston  315 . In this manner, spring  426  may be implemented using an extension spring in this illustrative example. Spring  426  may be an example of one implementation for spring  146  in  FIG. 1 . 
     Stopper  424  may be used to limit the movement of piston  315  in the direction opposite of arrow  430 . Stopper  422  and stopper  424  may be implemented using ring stoppers, in this illustrative example. 
     In this manner, compressed air regulator  314  may be used to send compressed air into inlet  313  in a manner that causes piston  315  to move within chamber  418  in a pumping manner. Piston  315  may be used to pump fluid  402  out of chamber  418 . As depicted, scooping structure  421  may be associated with piston  315 . Scooping structure  421  may be used to cause fluid  402  to converge, or be scooped, within chamber  418  and move in the direction of arrow  430 . 
     In this illustrative example, fluid dispensing system  300  may include heating system  428 . Heating system  428  may comprise plurality of heating coils  431 . Heating system  428  and plurality of heating coils  431  may be an example of implementations for heating system  118  and plurality of heating coils  140 , respectively, in  FIG. 1 . As depicted, plurality of heating coils  431  may be located between inner surface  416  and outer surface  414  of housing  302 . Plurality of heating coils  431  may be used to heat fluid  402  within chamber  418  to ensure that a desired viscosity for fluid  402  is maintained such that a desired mobility for fluid  402  is also maintained. In some cases, plurality of heating coils  431  may be controlled by controller  420 , as in this illustrative example. 
     Further, inner surface  416  may be comprised of a friction-reducing material, such as, for example, without limitation, a polytetrafluoroethylene material, configured to reduce friction created between inner surface  416  and fluid  402  as fluid  402  moves within chamber  418 . 
     As depicted, fluid  402  may be dispensed by being pushed out of nozzle  312  at exit  318  of chamber  418 . Tool system  324  may have tool housing  432  configured to house a number of tools (not shown in this view). Tool housing  432  may be an example of one implementation for tool housing  160  in  FIG. 1 . 
     In this illustrative example, fluid  402  may exit nozzle  312  through nozzle screen  320  in the direction of arrows  434 . The flow pattern of fluid  402  as fluid  402  is dispensed may be controlled by the shape of exit structure  322  and a plurality of holes (not shown) in nozzle screen  320 . This plurality of holes (not shown) in nozzle screen  320  may be implemented in a manner similar to plurality of holes  206  in nozzle screen  152  in  FIG. 2 . 
     Controller  420  may be used to control the dispensing of fluid  402  from fluid dispensing system  300  such that the supply of fluid  402  from fluid tank  404  into chamber  418  and the spraying of fluid  402  out through nozzle screen  320  are synchronized. In some cases, controller  420  may be used to perform other operations. For example, without limitation, fluid dispensing system  300  may be operated by a robotic operator. Controller  420  may be used to control the robotic operator and/or communicate with the robotic operator. 
     With reference now to  FIG. 5 , an illustration of tool system  324  and air protection device  326  from  FIGS. 3-4  is depicted in accordance with an illustrative embodiment. In this illustrative example, tool system  324  includes number of tools  500  housed within tool housing  432 . Number of tools  500  may be an example of one implementation for number of tools  158  in  FIG. 1 . 
     As depicted, number of tools  500  may include camera  502 , light source  504 , and sensor  506 . Camera  502 , light source  504 , and sensor  506  may be mounted to surface  508  of tool housing  432 . Further, camera  502 , light source  504 , and sensor  506  may be exposed at side  510  of tool housing  432 . Camera  502  may be used to monitor the dispensing of fluid  402  through nozzle screen  320  in  FIG. 4 . Light source  504  may provide light when needed. Sensor  506  may be used to measure the thickness of fluid  402  from  FIG. 4  being dispensed through nozzle screen  320 . 
     As depicted, air protection device  326  may be configured to allow air received through air line  328  in  FIG. 3  to flow through holes or slits (not shown) in air protection device  326  in the direction of arrows  511 . Air may flow in the direction of arrows  511  at a rate and in a manner such that air curtain  512  is created. Air curtain  512  may shield number of tools  500  from any fluid spatter resulting from the dispensing of fluid  402  in  FIG. 4  and/or from the elements in the environment around fluid dispensing system  300 . 
     With reference now to  FIG. 6 , an illustration of nozzle screen  320  from  FIGS. 3-4  is depicted in accordance with an illustrative embodiment. As depicted, nozzle screen  320  has first side  600  and second side  602 . First side  600  and second side  602  may be examples of implementations for first side  202  and second side  204 , respectively, in  FIG. 2 . Fluid  402  may be configured to enter nozzle screen  320  through first side  600  and exit nozzle screen  320  through second side  602 . 
     In this illustrative example, nozzle screen  320  has plurality of holes  604  with different sizes. Plurality of holes  604  may be an example of one implementation for plurality of holes  206  in  FIG. 2 . Plurality of holes  604  may be sized such that the flow rate of fluid  402  through each of plurality of holes  604  is substantially constant. Typically, the flow rate of fluid  402  increases towards center  605  and decreases away from center  605 . Further, flow rate may be substantially equal to the area of a hole multiplied by the velocity of fluid  402  flowing through that hole. 
     Consequently, the holes in plurality of holes  604  may be sized such that holes in plurality of holes  604  at or near center  605  of nozzle screen  320  have a smaller diameter than other holes at or near a periphery of nozzle screen  320  to ensure a substantially constant flow rate through each of plurality of holes  604 . For example, without limitation, hole  606 , which is further away from center  605  than hole  608 , may be larger in size than hole  608 . In this manner, fluid  402  may be dispensed in a desired manner with a desired level of accuracy. 
     Further, each of plurality of holes  604  may have a tapered shape configured to pressurize fluid  402  from  FIG. 4  as fluid  402  passes through nozzle screen  320 . In particular, each of plurality of holes  604  may have a larger diameter at first side  600  as compared to second side  602 . In this manner, fluid  402  may be pressurized as fluid  402  passes through nozzle screen  320 . Plurality of holes  604  may function as a plurality of small nozzles working in parallel. 
     With reference now to  FIG. 7 , an illustration of hole  606  from  FIG. 6  is depicted in accordance with an illustrative embodiment. In this illustrative example, hole  606  has first portion  700 , second portion  702 , and third portion  704 . First portion  700  is located closer to first side  600  of nozzle screen  320  and third portion  704  is located closer to second side  602  of nozzle screen  320 . 
     As depicted, within first portion  700  of hole  606 , the diameter of hole  606  decreases in size in the direction of arrow  705  from diameter  706  to diameter  708 . Within second portion  702  of hole  606 , the diameter of hole  606  remains substantially constant as diameter  708 . Further, within third portion  704  of hole  606 , the diameter of hole  606  further decreases in size in the direction of arrow  705  from diameter  708  to diameter  710 . 
     Fluid  402  from  FIG. 4  may pass through nozzle screen  320  in the direction of arrow  705 . As fluid  402  passes through hole  606 , the tapered shape of hole  606 , in particular the decrease in the diameter of hole  606  in the direction of arrow  705 , causes the exit pressure of fluid  402  passing through hole  606  to be increased. This increase in exit pressure may cause fluid  402  to exit hole  606  at an increased velocity such that fluid  402  may reach a further distance. 
     With reference now to  FIG. 8 , an illustration of a nozzle screen is depicted in accordance with an illustrative embodiment. In this illustrative example, nozzle screen  800  may be an example of another implementation for nozzle screen  152  in  FIG. 1 . Nozzle screen  800  may have plurality of holes  802  arranged in pattern  804 . Plurality of holes  802  may be another example of one implementation for plurality of holes  206  in  FIG. 2 . 
     In this illustrative example, the portion of plurality of holes  802  aligned with axis  806  may be larger than the other holes in plurality of holes  802 . Further, each of plurality of holes  802  may have a tapered shape configured such that any fluid passing through nozzle screen  800  may be pressurized. 
     The illustrations of fluid dispensing system  300  in  FIGS. 3-4 , tool system  324  in  FIG. 5 , nozzle screen  320  in  FIG. 6 , hole  606  in  FIG. 7 , and nozzle screen  800  in  FIG. 8  are not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the ones illustrated may be used. Some components may be optional. 
     The different components shown in  FIGS. 3-8  may be illustrative examples of how components shown in block form in  FIGS. 1-2  can be implemented as physical structures. Additionally, some of the components in  FIGS. 3-8  may be combined with components in  FIGS. 1-2 , used with components in  FIGS. 1-2 , or a combination of the two. 
     With reference now to  FIG. 9 , an illustration of a process for dispensing fluid is depicted in the form of a flowchart in accordance with an illustrative embodiment. The process illustrated in  FIG. 9  may be implemented using fluid dispensing system  102  in  FIG. 1 . 
     The process may begin by receiving fluid  104  within chamber  115  formed by inner surface  126  of housing  114  (operation  900 ). Further, inner surface  126  may be comprised of friction-reducing material  128 . Next, a tendency of fluid  104  to flow through chamber  115  may be increased (operation  902 ). 
     Thereafter, fluid  104  may be moved through chamber  115  towards exit  150  of chamber  115  using dispensing device  120  such that fluid  104  is dispensed out of chamber  115  through nozzle system  121  at exit  150  of chamber  115  (operation  904 ). The exit pressure of fluid  104  dispensed through nozzle system  121  may be controlled (operation  906 ), with the process terminating thereafter. In particular, nozzle system  121  may include nozzle  122  and nozzle screen  152  in which at least one of nozzle  122  and nozzle screen  152  may be used to control the exit pressure of fluid  104  such that fluid  104  exits nozzle system  121  at the desired velocity. 
     With reference now to  FIG. 10 , an illustration of a process for dispensing fluid is depicted in the form of a flowchart in accordance with an illustrative embodiment. The process in  FIG. 10  may be implemented using fluid dispensing system  102  in  FIG. 1 . 
     The process may begin by transferring fluid  104  from fluid source  132  to chamber  115  formed by inner surface  126  of housing  114  using fluid transfer system  116  (operation  1000 ). Fluid  104  may be received within chamber  115  (operation  1002 ). Inner surface  126  may be comprised of friction-reducing material  128 . In one illustrative example, friction-reducing material  128  may take the form of polytetrafluoroethylene  130 . 
     Further, friction generated between fluid  104  and inner surface  126  of chamber  115  as fluid  104  moves through chamber  115  may be reduced by friction-reducing material  128  in inner surface  126  of housing  114  (operation  1004 ). Fluid  104  within chamber  115  may be heated using heating system  118  comprising plurality of heating coils  140  located between inner surface  126  of housing  114  and outer surface  124  of housing  114  to reduce viscosity  110  of fluid  104  in chamber  115  to increase a mobility of fluid  104  within chamber  115  (operation  1006 ). 
     Fluid  104  in chamber  115  may be moved towards exit  150  of chamber  115  using dispensing device  120  such that fluid  104  is dispensed through nozzle screen  152  positioned at exit  150  of chamber  115  (operation  1008 ). Fluid  104  may be dispensed through plurality of holes  206  in nozzle screen  152  (operation  1010 ). Further, an exit pressure of fluid  104  may be increased as fluid  104  is dispensed through plurality of holes  206  in nozzle screen  152  in which plurality of holes  206  have plurality of sizes  207  selected such that fluid  104  exits nozzle screen  152  towards surface  106  in a desired spray pattern with a desired velocity (operation  1011 ). 
     Number of tools  158  housed within tool housing  160  associated with housing  114  may be used for performing fluid dispensing operations (operation  1012 ). An air curtain may be formed using air protection device  162  to shield number of tools  158  housed in tool housing  160  for use in performing fluid dispensing operations (operation  1014 ), with the process terminating thereafter. In particular, in operation  1014 , the air curtain formed by air protection device  162  may be used to shield number of tools  158  from fluid spatter and/or other types of debris. 
     Illustrative embodiments of the disclosure may be described in the context of aircraft manufacturing and service method  1100  as shown in  FIG. 11  and aircraft  1200  as shown in  FIG. 12 . Turning first to  FIG. 11 , an illustration of an aircraft manufacturing and service method is depicted in the form of a flowchart in accordance with an illustrative embodiment. During pre-production, aircraft manufacturing and service method  1100  may include specification and design  1102  of aircraft  1200  in  FIG. 12  and material procurement  1104 . 
     During production, component and subassembly manufacturing  1106  and system integration  1108  of aircraft  1200  in  FIG. 12  takes place. Thereafter, aircraft  1200  in  FIG. 12  may go through certification and delivery  1110  in order to be placed in service  1112 . While in service  1112  by a customer, aircraft  1200  in  FIG. 12  is scheduled for routine maintenance and service  1114 , which may include modification, reconfiguration, refurbishment, and other maintenance or service. 
     Each of the processes of aircraft manufacturing and service method  1100  may be performed or carried out by a system integrator, a third party, and/or an operator. In these examples, the operator may be a customer. For the purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may include, without limitation, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, a leasing company, a military entity, a service organization, and so on. 
     With reference now to  FIG. 12 , an illustration of an aircraft is depicted in the form of a block diagram in which an illustrative embodiment may be implemented. In this example, aircraft  1200  is produced by aircraft manufacturing and service method  1100  in  FIG. 11  and may include airframe  1202  with plurality of systems  1204  and interior  1206 . Examples of systems  1204  include one or more of propulsion system  1208 , electrical system  1210 , hydraulic system  1212 , and environmental system  1214 . Any number of other systems may be included. Although an aerospace example is shown, different illustrative embodiments may be applied to other industries, such as the automotive industry. 
     Apparatuses and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method  1100  in  FIG. 11 . In particular, fluid dispensing system  102  from  FIG. 1  may be used for applying fluid  104 , such as sealant  105 , to one or more objects of aircraft  1200  during any one of the stages of aircraft manufacturing and service method  1100 . For example, without limitation, fluid dispensing system  102  from  FIG. 1  may be used to dispense and apply sealant  105  in  FIG. 1  during at least one of component and subassembly manufacturing  1106 , system integration  1108 , routine maintenance and service  1114 , or some other stage of aircraft manufacturing and service method  1100 . 
     In one illustrative example, components or subassemblies produced in component and subassembly manufacturing  1106  in  FIG. 11  may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft  1200  is in service  1112  in  FIG. 11 . As yet another example, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during production stages, such as component and subassembly manufacturing  1106  and system integration  1108  in  FIG. 11 . One or more apparatus embodiments, method embodiments, or a combination thereof may be utilized while aircraft  1200  is in service  1112  and/or during maintenance and service  1114  in  FIG. 11 . The use of a number of the different illustrative embodiments may substantially expedite the assembly of and/or reduce the cost of aircraft  1200 . 
     The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatuses and methods in an illustrative embodiment. In this regard, each block in the flowcharts or block diagrams may represent a module, a segment, a function, and/or a portion of an operation or step. 
     In some alternative implementations of an illustrative embodiment, the function or functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved. Also, other blocks may be added in addition to the illustrated blocks in a flowchart or block diagram. 
     The description of the different illustrative embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative embodiments may provide different features as compared to other desirable embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.