Turbo gear units and components

Parallel shaft gear units have the capacity to transmit very high powers and speeds with high efficiency. The basis for this capacity is the ability of an optimized gear design in accordance with decades of experience, all current technical guidelines, plus specialized in-house calculations.

Parallel shaft gear units are designed and manufactured for powers up to 85 MW and speeds of up to 60 000 rpm. Three single-stage gearbox ranges cover gear ratios up to 11:1. For higher ratios a two-stage model range is available. All gear units are characterized by quiet operation and a long service life. These units are employed in just those situations where a well-developed system with very high reliability is required.

Integrally geared compressors have now established themselves in the process industry due to the lower space requirement and the higher total efficiency of the compressor package. It is precisely in air separation, oil and natural gas processing, and the general chemical industry, that new solutions and designs are being sought. Voith as supplier of the ‘core unit’ of an integrally geared compressor is developing and offering this expertise together with its customers.

Tailor-made to the relevant application and customer specification, integral gear units are designed and manufactured with up to 10 compressor stages, total unit weights of up to 70 tonnes, and gear pitch wheel diameters measuring over 3 meters. Gear ratios of up to 25:1 have been achieved thus far. The gear set is typically designed with single helical toothing and thrust collars.

Worldwide, Voith is known as the most experienced manufacturer of epicyclic gear units according to the Stoeckicht principle. With this design based on the well-known Stoeckicht principle, the unsupported sun wheel plus the unsupported radially elastic annulus halves effect an equal load distribution on the planets and this in turn produces less wear and tear on the components. The consequence is a high power density with low space requirement, combined with lower weight.

Voith designs epicyclic gear units up to powers of 45 MW, speeds of up to 80 000 rpm and torques of over 550 kNm. With single-stage design ratios up to 12:1 and with two-stage ratios up to 80:1 are achieved.

The power distribution gear unit converts torque in turbo drive trains at trans­mitted powers up to 170 000 kW or at speeds of up to 100 000 rpm. Power distribution gear units are especially well-suited for use where other types of gear units exceed their technical limits. They utilize the advantages of parallel shaft and planetary gear units and leverage these advantages to be able to combine high rotational speeds and high powers. Examples of where the need for this capability arises are machine trains with gas turbine-driven turbo compressors.
Even under harsh operating conditions, power distribution gear units exceed 250 000 operational hours. The gear unit efficiency in these high-end applications can reach levels of up to 98 percent.

Rotor turning gears are esteemed as a reliable and inexpensive aid for the turning of rotors. Compared with other design solutions they are wearresistant, longlasting and require low-maintenance. They offer the plant operator greater safety even at high turning speeds, high breakaway torques and high mass moments of inertia.

Rotor turning gear units are used primarily to break out and start shaft trains. They are also used to turn rotors slowly so that the armature cools down evenly and therefore remains dimensionally stable. At the same time, uneven debris in the blade channels is avoided. In addition, they are used to align and position shaft trains. The speeds of rotor turning gears are up to 500 rpm, the breakaway torques from 300 to 100 000 Nm.

The fully developed and high-quality Voith Turbo BHS diaphragm couplings have proven their worth, especially in turbo systems. As a firstclass product with low weight, they are capable of transmitting high torque at high speed. At the same time, they compensate for axial, radial and angular misalignment of two coupled shafts.

Diaphragm couplings are designed and manufactured by Voith for torques of up to 1 500 000 Nm and speeds of up to approx. 80 000 rpm. The standard program includes couplings suitable for angular misalignment up to 0.25°. Special model types for angular misalignments up to 0.5° are available. These high performance couplings meet the requirements of API 671 and ISO 10441. They are approved for Zone 1 and Zone 2, in accordance with ATEX.