GB1221229A - Labyrinth seal - Google Patents

Abstract

1,221,229. Turbines - inter-stage seals. GARRETT CORP. Dec.9, 1968 [Dec.11, 1967], No.58334/68. Heading F1T. [Also in Division F2] The invention relates to a labyrinth seal between two relatively movable members wherein one member carries a layer of material having a melting point not less than 1200‹ F. in a porous rub-tolerant form which is capable of being deformed when subjected to the application of localized force, the other member carrying two or more spaced continuous ribs having thin edges which extend in the direction of relative movement, movement being normally spaced by a small clearance of 0À002 to 0À006 inch from the deformable layer but liable to engage it in operation and then acting to deform the material so as to form a groove with the deformed material at one or each side thereof. The invention is described with reference to a labyrinth seal between two rotor discs 13 of a turbine and adjacent stator structure 17, a sleeve 15 formed with fins or ribs 16 being secured to one disc 13 and a tubular sleeve 18 coated internally with a layer of deformable material 24 being secured to the stator structure. An initial clearance is provided between the ribs 16 and the layer 24 as shown in Fig.2 but in operation the ribs may contact the layer as shown in Fig. 3 whereby annular grooves 26 are formed in the layer, the material of the layer being deformed and forming ridges 27. Relative axial movement of the parts is also indicated in Fig.3. The deformable layer may be formed of porous material such as sintered metallic fibre. The layer may be formed by flame spraying. It may be formed of a material containing aluminium or silver; it may be formed of a material containing aluminium and nickel, or silver and manganese. The edges of the ribs 16 may be coated with a layer of wearresisting material such as molybdenum.