MARC Steam Turbines The Modular Steam Turbine Generation

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Turbine module In industrial turbines, part of the steam often is extracted for production purposes, heating steam systems or generative feed water heating. In that case, in addition to several bleedings, two controlled extractions can also be provided. The MARC concept allows an individual and optimized design of the different turbine elements, according to specific requirements, such as the pressure level and the extraction steam quantity. Depending on the live steam conditions and the specified operation mode, either a nozzle group control with or without bypass or a throttle control may be se- 8 lected. The control stage, either single or two-row type, and the number of reaction stages are especially adapted to the specific requirements. For all reaction stages the low-loss round-head profile is used. The HP blades are provided with milled shrouds, whereas the last blade rows are mostly designed with conically twisted blades, the blade ends of which being tip-thinned on one side.The rotor blades of the last rows are grouped by means of damping and bind-ing wires in conformity with the results of vibration calculations. Due to the small flow volume, steam admission of the impulse wheel is only necessary in the upper casing half, how-ever, the lower half can also be utilized, if required. In that case, a bypass leads to the lower nozzle group. The exhaust casing is a welded construction and may either be fitted facing upward or downward, depending on the site conditions. MARC steam turbines have been designed for highest operating security and utmost reliability. As the highest thermal impact on the steam carrying parts occurs at load changes, the casing, guide blade carrier and inner casing have been developed for a high thermal elasticity.
The following design features apply for all turbine types: multi-stage reaction design maximum symmetry of the upper and lower casings symmetrical temperature distribution at the circumference in all crosssections under all load conditions single-piece forged rotor labyrinth sealing glands between rotor and casing split tilting pad sleeve bearings self-aligning axial bearing, for doublesided loading nozzle group control guide blade carrier Turbine rotors The reaction turbines are supplied with a drum-type rotor. The turbine rotors, the balance piston and the impulse wheel disc as well as the subsequent drum parts are solid forging of high temperature material.The rotor design is based on modern calculation methods to meet the highest demands regarding smooth and resonant-free operation. The bladed rotors are statically and dynamically bal-anced at operating speed in a modern high-speed vacuum balancing plant, in a way that the shaft vibrations over the whole speed range are considerably below ISO10816 permitted values. Bearings The radial bearings are of multiface sleeve or tilting pad type. A stable rotor position is maintained by hydrodynamical oil wedges, equally spaced on the circumference.The axial forces resulting from pressure differences in the blading are mainly absorbed by the balance piston. A double-sided segmental axial bearing absorbs the residual thrust and the coupling forces. 9
Page 1 and 2: MARC ® Steam Turbines The Modular
Page 3 and 4: The first steam turbines under the
Page 5 and 6: The turbo generator unit comprises
Page 7: The new MARC 1 The success formula
Page 11 and 12: Reaction Part The multi-stage react
Page 13 and 14: Gearbox/Generator module Gearbox an
Page 15 and 16: Control oil module Control oil syst
Page 17 and 18: Control cabinet Field ISDN Router E
Page 19 and 20: Service Our experienced Turbine Ser

MARC Steam Turbines The Modular Steam Turbine Generation

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