4 MW Steam turbine kit is of modular structure - the turbine, gearbox, generator and oil system are mounted on a common frame thus enabling shipment of a fully assembled and tested plant requiring minimum installation work. Turbine design is of a novel type. The first turbine stage is a radial wheel, that produces enthalpy drop of up to 300 kJ/kg. Steam is then fed through a channel into the axial passage.

    The unit is in its standard design of a condensing type. The high speed turbine has nine stages. The first stage is of radial, the others are of axial type. The turbine rotor consists of individual bladed discs that are tightened together with 12 bolts, mutual centricity is ensured by means of radially inserted pins. Condenser is of four pass tube bundle design. It has minimum installation space requirements and low cooling water consumption. 

    Turbine modular structure allows fast re-design and reassembly of a standard unit to one according to customer's needs. Backpressure modification of the condensing turbine can be achieved simply by omitting the last 3 stages of the condensing turbine rotor and by using a different steam outlet casing. All other unit components remain identical. 

    Steam flow control is achieved by using moving segments that gradually close the inlet channels of radial stage guide vanes. This approach minimizes the losses due to throttling and significantly reduce the overall turbine weight. Standard throttle valve control is also available. 

    Service tested pivoted pad bearings with each pad being independently lubricated minimize the friction losses. 

    Oil system consists of main oil pump that supplies pressurized lube oil for the turbine, gearbox and the generator. The lubrication oil is cooled in an oil cooler that consists of two parallel sections. The first section performs cooling of the entire oil flow, the other section is back up one. Oil filters fitted with a clogging indicator are backed up in a similar way. Overall arrangement enables the oil pipe system and the oil filters to be cleaned or changed while the turbine is running. Electric AC primer pump is used during the unit start up. Auxiliary DC emergency oil pump is actuated in the event of mains fall out or as a backup while the turbine is running. The oil tank is located on the unit's base frame. 

    The turbine unit is able to supply public electric networks, or to operate as an independent electric power source. The unit can also be used in a combined gas-steam cycle. 

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    TECHNICAL DATA
Inlet steam pressure Pomax = 3 - 4 MPa
Inlet steam temperature tomax = 350 - 450 degC
Turbine speed nmax = 12000 min^-1
Generator speed ng = 1500 or 3000 min^-1
Condenser pressure Pk = 0.0065 MPa
Nominal performance of generator Nn = 4 MW