Patent Publication Number: US-6216438-B1

Title: Pipeline duct through two or more walls of an axial compressor of a gas turbine

Description:
FIELD OF THE INVENTION 
     The present invention pertains to a pipeline duct through an opening of a vane support housing and an opening in an outer wall of an axial compressor of a gas turbine. 
     BACKGROUND OF THE INVENTION 
     To bleed compressed air from the vane support interior space, a pipeline is firmly clamped in a discharge opening of the outer wall of the compressor housing in a gas turbine developed by the applicant. 
     The pipeline duct is led through two or more walls, which are displaced horizontally and vertically in relation to one another because of relative movements. The pipeline is sealed by soft sealing rings at the discharge opening of the vane support housing. The drawback of this design is that the ducts become loose when the elasticity is lost due to increased temperature of the sealing rings and thus leaks will develop. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     The object of the present invention is to provide a temperature-resistant sealing which has low wear, on the one hand, and guarantees an unlimited freedom of movement of the pipe duct in the radial and axial directions, on the other hand. 
     Compressed air is bled from the vane support housing of an axial compressor of a gas turbine via a pipeline by means of the device according to the present invention. Since the vane support is located within the axial compressor housing, the pipeline must be led through the annular space of the axial compressor, which is formed by the walls of the vane support housing and of the compressor housing. 
     The different pressure levels in the vane support interior space, in the annular space and outside the axial compressor housing require sealing of the spaces against each other and against the pipeline. Since the housing walls and the pipeline are subject to different thermal expansions, the sealing must permit a relative movement of the components in the horizontal and vertical directions. 
     The upper part of the pipeline is therefore firmly clamped according to the present invention at the duct and the bleeder connection of the compressor housing wall with a flange and is sealed by two seals. 
     The pipe is sealed by a piston ring at the duct and the discharge opening of the vane support. The piston ring permits the relative movement of the pipe and the compressor housing in relation to the vane support in the vertical direction. 
     The piston ring is guided at the vane support wall by two fastening rings. Due to their free spaces, the fastening rings permit the relative movement of the pipe and the compressor housing in relation to the vane support in the horizontal direction. 
     The device according to the present invention can be applied in all cases in which a pipeline passes through a plurality of walls which are subject to relative movements in a sealed manner. 
     In addition, the device is temperature-resistant due to being made of metal, and no wearing parts are needed. Unlimited freedom of movement in the radial and axial directions is possible due to the predetermined free spaces. The mounting of the device is very simple. The risk of excitation due to forces generated by flow is ruled out. 
     The present invention will be explained in greater detail based on a schematic exemplary embodiment. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a longitudinal sectional view through an axial compressor of a gas turbine with an air bleeder pipe according to the invention; and 
     FIG. 2 is a cross sectional view through the pipeline duct according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in particular, FIG. 1 shows a longitudinal section through an axial compressor of a gas turbine with blades  21  arranged on the shaft  19  and with guide vanes  22  fastened in the vane support  23  as well as with an impeller  18  arranged under the diffusor  20  on the shaft  19 . 
     Air is bled from the housing vane support  1  via a pipeline  2 . Since the housing vane support  1  is located within the compressor housing  3 , the pipeline  2  must be led through the annular space  4 , which is formed by the walls of the housings  1  and  3 . 
     The different pressure levels in the vane support interior space  5  with the discharge openings  25 , in the annular space  4  and outside the compressor housing  3  require sealing of the spaces  5  and  4  against each other and against the pipeline. Since the housing walls  1 ,  3  and the pipeline  2  are subject to different thermal expansions, the sealing must permit a relative movement of the built-in parts in the horizontal and vertical directions. 
     According to the present invention, the upper pipe section  2  is firmly clamped with the flange  14  at the duct  6  of the outer housing wall  3  by the bleeder connection  15  and by means of fastening elements  16  and is sealed by two seals  7 . 
     Corresponding to FIG. 2, the lower end of the pipe  2  is sealed by a piston ring  8  at the discharge opening  17  of the housing vane support  1 . The piston ring  8  permits the relative movement of the pipe  2  and the housing  3  in relation to the housing vane support  1  in the vertical direction. 
     The piston ring  8  is guided at the housing vane support wall  1  by two fastening rings  9  and  10 . The fastening rings  9 ,  10  permit the relative movement of the pipe  2  and the housing  3  in relation to the housing vane support  1  in the horizontal direction due to their free spaces or inner and outer expansions  11 ,  12 ,  13 . 
     The device according to the present invention may also be used in cases in which a pipeline  2  passes in a sealed manner through a plurality of walls, which are subject to relative movements. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.