Alstom Technology Limited

Gec Alsthom Sa

Gec Alsthom Electromecanique S.a.

Alain Hassan

Jacques Pajot

Jacques Comon

A steam turbineconstructed in accordance with the present invention comprises a high-pressure moduleand a low-pressure module, a speed-reducing gearbox, and an alternator, and wherein the high-pressure modulehas a single stage of blades. This single stage of bladesperforms the same function as a multi-stage high-pressure module, but with a blade design that is different from the blade design of multi-stage steam turbines. For example, the pressure ratio between the inlet and the outlet of the high-pressure modulemay be in the range 3 to 20.

Steam turbine including a high-pressure body having a single state of blades

A method of heat treatment for two welded-together parts of different steel alloy grades, the first part, called A, having critical heating transformation temperatures AC.sub.1 A and AC.sub.3 A and an optimum post-welding treatment temperature .theta..sub.A which is lower than AC.sub.1 A, the second part, called B, having critical heating transformation temperatures AC.sub.1 B and AC.sub.3 B, which are respectively lower than AC.sub.1 A and AC.sub.3 A and an optimum post-welding treatment temperature .theta..sub.B which is lower than AC.sub.1 B and .theta..sub.A, wherein a first heat treatment cycle is carried out at said temperature .theta..sub.A followed by a second heat treatment cycle at a temperature .theta..sub.B. Between the two cycles, the temperature is reduced to below 100.degree. C.

Method of heat treatment for two welded-together parts of different

A device for causing a drop in the pressure of high pressure oil controlling admission valves of a steam turbine in the event of excess speed, the device comprising a speed trip (2) constrained to rotate with the shaft (1) of the turbine and fed downstream from a constriction (5) with low pressure oil from the low pressure lubricating oil circuit of the turbine, the device being characterized in that it comprises a hydraulically controlled valve (9) having a hollow body (23) containing a closing valve member (24) for closing a discharge orifice (12) connected to said high pressure oil circuit, said closing valve member (24) being connected to a plate (25) dividing in sealed manner the inside of the body of the hydraulically controlled valve (9) into two compartments, a 'first' one (11) of said compartments being situated on the same side as said discharge orifice (12) and also including at least one evacuation orifice (37), and the 'second', other one of the compartments (8) being fed downstream via a feed orifice (7) from a constriction (5) with oil from said low pressure oil circuit, said second compartment (8) being also connected without constriction to said speed trip (2), and in that the moving equipment (10) constituted by said closing valve member (24) and said plate (25) is guided axially by guide means (27, 28, 29), said moving equipment also being subjected to a resilient force (33) tending to move said valve member (2) away from the discharge orifice (12).

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Paris, France

Alain Hassan