Abstract: Turbines having rotor blades (3, 5) fixed in dovetail grooves (14) in the rotor periphery have bridge pieces (17) which provide in effect a false floor to the inter-stage recess (8, 11) to close off the machining recess from the fluid path. This invention provides a method of fixing this bridge piece which is simple, positive and avoids loading the rotor disc rims with additional centrifugal force. The dovetail groove (14) for the blade root is continued into a raised portion or the rotor recess periphery. This raised portion is grooved circumferentially (21) and the stem (19) of the `T` section bridge piece fits snugly in the groove. A dovetail section key (23) is inserted through the blade root dovetail groove (14) and into the raised portion of the rotor, passing through a hole in the stem (19) of the bridge piece. The latter is thus positively located and locked in position.

Abstract: An electric power generating system employing a gas turbine (1) and a steam turbine (5) and a gasifier (9) supplying fuel-gas to the gas turbine (1) and to a steam generating fluidized bed combustor (37), the latter providing steam for the steam turbine (5). An auxiliary steam turbine (21), driving an electric generator (22), is also supplied by the circulating fluidized bed combustor steam generator (37). Since the gasifier (9) cannot be reversibly turned down easily, on a fall in load on the main steam turbine (5), the excess steam generated is diverted to the auxiliary steam generator (21) and the gasifier (9) kept running efficiently.

Abstract: A gas valve which has provision for a reverse flow pulse of high pressure gas. The valve includes a reservoir which is loaded with high pressure gas during normal operation which is released into the main flow path by an applied pressure reduction. The valve is fitted to a porous ceramic "candle" filter between dirty and clean gas zones. The high pressure gas pulse reverses flow through the filter and blows off any aggregated dirt. A shut-off valve is arranged to shut the valve in the event the ceramic filter breaks. The valve is efficient and uses only a metered amount of high pressure gas with little loss of pressure between supply and flushing.