Abstract:
A system has a surface intended to separate two chambers within the system. The surface has an aperture for allowing passage of at least one communication conduit. A shroud is positioned on the surface at the aperture, and has at least two portions defining a central opening to allow the communication conduit to pass through the aperture and shroud. The two portions of shroud have mating clamp ears in contact with each other. Securement members tighten the clamp ears against each other to provide a seal at an end of the shroud remote from the surface.

Description:
BACKGROUND 
       [0001]    This application relates to a shroud that includes at least two pieces which are clamped together to seal a feed-through location for conduits, such as wire harnesses of fluid tubes. 
         [0002]    Communication conduits, such as those carrying electric wires, fluid tubes, or other communication media are known, and are provided in most modern mechanical systems. These conduits must sometimes pass through walls within the systems, and the apertures that they pass through must be sealed. One such application would be in a gas turbine engine. 
         [0003]    In a gas turbine engine, a compressor compresses air and delivers it into a combustor section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate. A very complex electric control controls the operation of the gas turbine engine, and several associated systems. As an example, the associated systems include fuel and lubricant pumps. 
         [0004]    Within the gas turbine engine, there are areas which are extremely hot, and areas which may be subject to flame risk. Thus, a firewall is typically provided within the gas turbine engine to separate areas at flame risk from other areas that should be protected from the flame risk. One example would be a location where the control mentioned above is located. 
         [0005]    Wire harnesses and fluid tubes may need to pass through this firewall. Typically, so called “feed-through” holes or apertures have allowed the communication conduits media to extend through the firewall. Grommets of various sorts have been provided to seal the aperture through which the communication conduit passes. 
       SUMMARY 
       [0006]    In a featured embodiment, a system has a surface intended to separate two chambers within the system. The surface has an aperture for allowing passage of at least one communication conduit. A shroud is positioned on the surface at the aperture and has at least two portions defining a central opening to allow the communication conduit to pass through the aperture and the shroud. The two portions have mating clamp ears in contact with each other. Securement members tighten the clamp ears against each other to provide a seal at an end of the shroud remote from the surface. 
         [0007]    In another embodiment according to the previous embodiment, the surface is a firewall for use in a gas turbine engine. 
         [0008]    In another embodiment according to any of the previous embodiments, the communication conduit includes at least one electric wire. 
         [0009]    In another embodiment according to any of the previous embodiments, a grounding element is received within at least one of the shroud portions. The grounding element electrically grounds the communication conduit. 
         [0010]    In another embodiment according to any of the previous embodiments, the communication conduit includes at least a fluid tube. 
         [0011]    In another embodiment according to any of the previous embodiments, there are two mating halves of the shroud which are secured together. 
         [0012]    In another embodiment according to any of the previous embodiments, the shroud has a platform base receiving securement members to secure the shroud to the surface. 
         [0013]    In another embodiment according to any of the previous embodiments, the platform base is formed of two halves formed equally in each of the two portions of the shroud. 
         [0014]    In another embodiment according to any of the previous embodiments, the platform base includes a full cylindrical portion formed on one of the two portions of the shroud. A smaller portion is formed on another of the at least two portions of the shroud. 
         [0015]    In another embodiment according to any of the previous embodiments, a fiberglass tape is wrapped around the communication conduit at the location of the clamp ears to provide a better seal. 
         [0016]    In another embodiment according to any of the previous embodiments, the shroud includes a plurality of openings at the remote end. There are outer ends to the at least two portions of the shroud with the clamp ears at the outer ends. There is at least one of the plurality of opening positioned adjacent the clamp ears at the outer ends, and at least one intermediate opening intermediate the outer ones of the openings, with clamp surfaces provided between the outer ones of the opening and the at least one intermediate opening. There are securement members tightening intermediate sealing surfaces to also provide a seal at the intermediate opening. 
         [0017]    In another featured embodiment, a gas turbine engine has a compressor, a combustor, a turbine, and a firewall separating a first chamber housing at least one of the compressor, combustor and turbine from a chamber housing a controller for the gas turbine engine. The firewall has an aperture for allowing passage of at least one communication conduit. A shroud is positioned on the firewall at the aperture. The shroud has at least two portions defining a central opening to allow the communication conduit to pass through the aperture and the shroud. The two portions of the shroud have mating clamp ears in contact with each other. Securement members tighten the clamp ears against each other to provide a seal at an end of the shroud remote from the firewall. 
         [0018]    In another embodiment according to any of the previous embodiments, there are two mating halves of the shroud that are secured together. 
         [0019]    In another embodiment according to any of the previous embodiments, the shroud has a platform base receiving securement tightening members to secure the shroud to the firewall. 
         [0020]    In another embodiment according to any of the previous embodiments, the platform base is formed of two halves formed equally in each of the two portions of the shroud. 
         [0021]    In another embodiment according to any of the previous embodiments, the platform base includes a full cylindrical portion formed on one of the two portions of the shroud. A smaller portion is formed on another of the at least two portions of the shroud. 
         [0022]    In another embodiment according to any of the previous embodiments, fiberglass tape is wrapped around the communication conduit at the location of the clamp ears to provide a better seal. 
         [0023]    In another embodiment according to any of the previous embodiments, the communication conduit is an electric wire. A grounding element is received within at least one of the shroud portions. The grounding element electrically grounds the electric wire. 
         [0024]    In another embodiment according to any of the previous embodiments, the shroud includes a plurality of openings at the remote end. There are outer ends to the at least two portions of the shroud with the clamp ears at the outer ends. At least one of the plurality of openings is positioned adjacent the clamp ears at the outer ends, and at least one intermediate opening intermediate the outer ones of the openings. Clamp surfaces are provided between the outer ones of the opening and the at least one intermediate opening. Securement members tighten intermediate sealing surfaces to also provide a seal at the intermediate opening. 
         [0025]    These and other features of this application may be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  schematically shows a gas turbine engine. 
           [0027]      FIG. 2A  shows a first embodiment shroud. 
           [0028]      FIG. 2B  is a cross-sectional view through the  FIG. 2A  shroud. 
           [0029]      FIG. 3  shows an optional feature. 
           [0030]      FIG. 4  shows another optional feature. 
           [0031]      FIG. 5A  shows a second embodiment. 
           [0032]      FIG. 5B  is a cross-sectional view through the second embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]      FIG. 1  schematically illustrates a gas turbine engine  20 . The gas turbine engine  20  is disclosed herein as a two-spool turbofan that generally incorporates a fan section  22 , a compressor section  24 , a combustor section  26  and a turbine section  28 . Alternative engines might include an augmentor section (not shown) among other systems or features. The fan section  22  drives air along a bypass flowpath B in a bypass duct defined within a nacelle  15 , while the compressor section  24  drives air along a core flowpath C for compression and communication into the combustor section  26  then expansion through the turbine section  28 . Although depicted as a turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures. 
         [0034]    The engine  20  generally includes a low speed spool  30  and a high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided. 
         [0035]    The low speed spool  30  generally includes an inner shaft  40  that interconnects a fan  42 , a low pressure compressor  44  and a low pressure turbine  46 . The inner shaft  40  is connected to the fan  42  through a geared architecture  48  to drive the fan  42  at a lower speed than the low speed spool  30 . The high speed spool  32  includes an outer shaft  50  that interconnects a high pressure compressor  52  and high pressure turbine  54 . A combustor  56  is arranged between the high pressure compressor  52  and the high pressure turbine  54 . A mid-turbine frame  57  of the engine static structure  36  is arranged generally between the high pressure turbine  54  and the low pressure turbine  46 . The mid-turbine frame  57  further supports bearing systems  38  in the turbine section  28 . The inner shaft  40  and the outer shaft  50  are concentric and rotate via bearing systems  38  about the engine central longitudinal axis A which is collinear with their longitudinal axes. 
         [0036]    The core airflow is compressed by the low pressure compressor  44  then the high pressure compressor  52 , mixed and burned with fuel in the combustor  56 , then expanded over the high pressure turbine  54  and low pressure turbine  46 . The mid-turbine frame  57  includes airfoils  59  which are in the core airflow path. The turbines  46 ,  54  rotationally drive the respective low speed spool  30  and high speed spool  32  in response to the expansion. 
         [0037]    The engine  20  in one example is a high-bypass geared aircraft engine. In a further example, the engine  20  bypass ratio is greater than about six (6), with an example embodiment being greater than ten (10), the geared architecture  48  is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine  46  has a pressure ratio that is greater than about 5. In one disclosed embodiment, the engine  20  bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor  44 , and the low pressure turbine  46  has a pressure ratio that is greater than about 5:1. Low pressure turbine  46  pressure ratio is pressure measured prior to inlet of low pressure turbine  46  as related to the pressure at the outlet of the low pressure turbine  46  prior to an exhaust nozzle. The geared architecture  48  may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.5:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans. 
         [0038]    A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section  22  of the engine  20  is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. The flight condition of 0.8 Mach and 35,000 ft, with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point. “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about  1 . 45 . “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram ° R)/(518.7° R)] 0.5 . The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second. 
         [0039]      FIG. 2A  shows a way to communicate conduits such as may include wire harnesses or fluid tubes within a gas turbine engine such as the gas turbine engine  20  of  FIG. 1 . As shown, a firewall  80  may be included within the gas turbine engine at a location to separate one chamber  86  from another chamber  84 . The chamber  86  may be in the vicinity of the compressor section, as an example, and may have some flame risk. A controller  88 , which may be a FADEC (Full Authority Digital Engine Control) is positioned in the chamber  84 . The firewall  80  serves to limit the risk of flame reaching the controller  88 . As shown, a shroud  82  includes shroud halves  102 A and  102 B. Each shroud half  102 A and  102 B has a base  103 . 
         [0040]    A communication conduit  90  is shown extending from an end  92  within chamber  86  to a remote end connected to the controller  88 . In this embodiment, the conduit  90  would likely be a wire harness, and can convey control signals from the control  88  to various components within the engine, and can further communicate information from the engine, such as from sensors, back to the controller  88 . 
         [0041]    As shown in  FIG. 2B , clamp ears  106  are formed on each side of a central chamber  107  formed in the shroud halves  102 A and  102 B. The communication conduit  90  may in fact be a plurality of wires, such as in a wire harness. Fiberglass tape is shown at  94 , and may be wrapped around the wires or the harness. Bolts  104  clamp the shroud halves together at the clamp ears  106 , to ensure a tight seal. 
         [0042]    With this simple arrangement, the shroud  82  allows the communication conduit to pass through an aperture  105  in the firewall  80 , and a very reliable seal is provided. 
         [0043]      FIG. 3  shows an optional feature wherein a base  110  which is connected to the firewall  80  is not formed in each of the halves  102 A and  102 B. Rather, one of the halves may have a portion  114  that is a full circular portion, and the other may have a smaller portion  112  to provide a portion of the base. 
         [0044]      FIG. 4  shows another feature wherein an inner wall  120  of one of the shroud halves can be formed with a grounding element  122 . The grounding element  122  may serve to ground an electrical conduit  107  passing through the shroud, such as by connecting to a braided shield on a wire harness. 
         [0045]      FIG. 5A  shows another embodiment  150 . Embodiment  150  is a shroud which is again attached at base  154  to a firewall  80  to separate chambers  84  and  86 . In  FIG. 5A  a shroud half  152 A is shown. Bolts  160  are positioned between plural shroud passages  161 ,  162 , and  163  at an end remote from firewall  80 . 
         [0046]    As can be seen in  FIG. 5B , each of the passages  160 ,  162 , and  163  may receive separate conduits  170  (wire),  152  (wires) and  165  (fluid tube). There are two shroud portions  152 A and  152 B. As shown, there are outer clamp ears  176  in contact, and intermediate clamp surfaces  178  in contact. Thus, when the bolts  160  are tightened, the same sealing effect as described above will be achieved for each of the passages  161 ,  162 , and  163 . 
         [0047]    Although bolts  100 ,  104  and  160  are disclosed, other securement members may be used. 
         [0048]    The shroud  150  includes outer ends to the two portions  152 A and  152 B with clamp ears  176  at the outer ends. Openings  161  and  163  are positioned adjacent the clamp ears  176  at the outer ends. Intermediate opening  162  is intermediate the outer openings  161  and  163 . Clamp surfaces  178  are provided between the outer openings  161  and  163  and intermediate opening  162 . Securement members  160  tighten the intermediate sealing surfaces to also provide a seal at the intermediate opening. 
         [0049]    Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.