| 摘要 |
A turbomachine comprises a housing (71) defining a bearing cavity (71) and a turbine chamber (77a) separated by a first wall. A heat shield (72) is disposed between the first wall and the turbine wheel (77), a heat shield cavity (78) being defined between the first wall and the heat shield (72). The shaft (81) extends through a passage (85) defined at least in part by a first aperture (86) in said wall and a second aperture (87) in the heat shield (72). A first seal (88) is provided between the shaft (81) and said first aperture (86). The housing defines a first gas channel (79) communicating with the heat shield cavity (78) for connection to a pressure source for raising pressure within the heat shield cavity (78). A second channel (92) is provided between the heat shield cavity (78) and said passage (85), the second channel opening to said passage (85) on the opposite side of said first seal (88) to said bearing assembly (82). A second seal (89) is provided between the shaft (81) and said second aperture (87).
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