FLENDER Gear units

The portfolio of FLENDER gear units ranges from universal standard gear units through application-specific gear units to customer-specific solutions in nearly every sector of raw material production, industry, and further processing.


This range comprises helical and bevel-helical gear units, single-stage and multi-stage planetary gear units. Thanks to the different gear unit types and designs the series offer an almost unlimited variety of designs in a torque range from approx. 2,000 to 2,600,000 Nm.


The modular system enables extremely short delivery times. The main add-on parts are already included in the standard range which means that adapting a gear unit to the customer's requirements does not affect the delivery time.


Your benefits

  • Can be universally used
  • Modular system
  • Fast availability worldwide
  • High power capacity


Well proven over decades in countless drive applications


FLENDER Gear units


Modern drive solutions have to withstand the most varied influences, achieve maximum efficiency, and be absolutely reliable. When these requirements are met, high plant availability and low product life cycle costs can be ensured. With the Siemens FLENDER gear units EURO-TECH offers you the most comprehensive range of industrial gear units in the world.


Simply select the ideal gear unit for your requirements and benefit from the advantages offered to you by our standard range. The high quality, the fast availability worldwide, and the attractive price level are the main strengths of this range of gear units. Horizontal or vertical mounting positions, different versions of helical, bevel and bevel-helical gear units, and the compact design of our gear units give you maximum flexibility in the design of your plant.


Application examples


  • Belt conveyor drives
  • Bucket elevator drives
  • Agitator drives
  • Hoisting gear drives
  • Travelling gear drives
  • Paper machine drives
  • Dryer drives
  • Water screw drives




  • Short delivery times
  • Fast availability worldwide
  • Attractive price/performance ratio
  • Mainly non-contacting and wear-resistant labyrinth seals possible
  • Flanged output shafts for easy gear unit installation

FLENDER Planetary gear units


With the Siemens FLENDER planetary gear unit series, EURO-TECH provides also standardized gear unit solutions for higher power rating ranges in the proven FLENDER quality. With 27 sizes and seven basic types the PLANUREX series ensures torque ranges of up to 2,600,000 Nm and transmission ratios of 4,000:1.


The specific requirements to be taken into account for bucket wheel, slewing gear and travelling gear drives in the field of materials handling have already been realized in standardized products. Get your benefit from the advantages of a standard product available for your industry.


Examples of application


  • Roller presses
  • Slewing gear drives
  • Bucket wheel drives
  • Apron conveyor drives
  • Agitator drives
  • Travelling gear drives
  • Rotary kiln drives
  • Central drives for tube mills


Advantages of the product
  • Low weight and compact, place-saving design owing to a load sharing system
  • Saving operating expenses owing to high efficiencies and optimized maintenance intervals
  • Easy to combine with other gear units, e.g. primary helical, worm, bevel, or bevel-helical gear units
  • Low-noise running owing to low rolling and sliding speeds at the tooth flanks

FLENDER SIG Standard industrial gear units


With this completely new SIEMENS FLENDER SIG standard gear unit series, EURO-TECH provides optimal universal solutions for the drive tasks of tomorrow.


Whether materials handling, the building materials industry, the steel industry, metallurgical engineering, or process technology – the classical industrial branches and the works for the production of raw materials require even more standardization, flexibility, and performance of their applications.


The new gear units of the FLENDER SIG series are extremely compact and provide even higher torques for the same size. In addition, the torque grading was harmonized with the result that the customer will always find the right gear unit.



The new mounting options and the unique options of add-on pieces and coolers offer the customer considerably more flexibility when planning and designing his plant. Highest quality and interdisciplinary knowledge of the drive train as well as improved rolling bearing life and, if requested, dustproof TACONITE seals ensure continuous reliable operation and low life cycle costs.


The new industrial gear unit series setting high standards will successively replace the standard FLENDER gear unit series which was tried and tested a hundred thousand times.


Today, just one year after launching them onto the market, Siemens is offering all seven types of FLENDER SIG for horizontal mounting. The Siemens modular gear unit kit enables a huge range of possible variants to be constructed – which means that FLENDER SIG is available to you in many sizes for base or shaft mounting right now.


  • Even higher torques for the same size
  • Even higher flexibility owing to additional mounting position
  • Even higher availability of the plant owing to improved rolling bearing life
  • Even closer to the torque desired by the customer owing to harmonized torque grading
  • Great diversity owing to 5 types with solid shaft or different hollow shaft variants
  • Optionally available with dustproof TACONITE seals
  • If required, internal cooling or standardized fan
  • High availability worldwide
  • Attractive price-performance ratio
  • Higher operational reliability with increased power capacity

FLENDER SIP Planetary gear units


With the FLENDER SIP® planetary gear unit, Siemens offers an attractive price-performance ratio for the low up to average torque range in the well-proven FLENDER quality – available with EURO-TECH now. The finely graduated series covers a torque range from 10,000 to 80,000 Nm. The modular design allowsthe standardization of many basis components – and therefore opens the door for production in cost-effective batch sizes – but at the same time with a high quality standard.


You profit from cost-efficient gear units, high global availability and short delivery times. And yet another advantage: the specific requirements of a wide range of sectors has already been implemented in this range of standardized gear units.




  • Environmental
  • Chemical and water treatment
  • Conveyor technology
  • Mining
  • Cement
  • Coal
  • Gypsum




  • Well-proven FLENDER quality at an attractive price-performance ratio
  • Short delivery times
  • High global availability
  • Gearing with a high endurance strength and large planetary bearings for a long service life
  • High energy efficiency
  • Can be simply combined with Siemens geared motors (ratios for a single gear 25 – 45, in combination with geared motors, 300 – 15,000)
  • Smooth operation as a result of the large profile overlap in the gearing


FLENDER Application specific gear units

Each industry has its own requirements, needs specific solutions and specialist advice. EURO-TECH is the right partner for each industrial sector, knows the customers and their markets. Thanks to the FLENDER modular system, many reliable and long-life industry-specific drive solutions can be realized with the standard product range. The resulting added value opens up greater market chances for the customer. For: The standard and special solutions tried and tested in practice lead to cost savings.


FLENDER Gear units for bucket elevators


Bucket elevators serve to vertically transport large masses of bulk material to different heights without creating dust, then dump it. The height to be overcome is frequently more than 200 meters. The weights to be moved are enormous.


The carrying elements in bucket elevators are central or double chain strands, link chains, or belts to which the buckets are attached. The drive is located at the upper station. The features specified for the drives destined for these applications are similar to those for steeply ascending belt conveyors. Bucket elevators require a comparatively high input power. The drive must be soft-starting because of the high starting power, and this is achieved by means of fluid couplings in the drive train. Bevel helical gear units are normally used for this purpose as single or twin drives on a base frame or swing base.


FLENDER gear units are a crucial element of the drive train. They are characterized by maximum performance and operational reliability as well as optimal availability. Auxiliary drives (maintenance or load drives) and backstops are supplied as standard. The gear unit and the auxiliary drive are therefore perfectly matched.


Technical data


  • Types: Bevel helical gear unit
  • Sizes: 15 sizes from 4 to 18
  • No. of gear stages: 3
  • Power ratings: 9.7 to 1809 kW (auxiliary drive power from 0.75 to 37 kW)
  • Transmission ratios: 25 - 71
  • Nominal torques: 6.7 to 240 kNm
  • Mounting positions: Horizontal


  • Maximum power capacity
  • Maximum operational reliability
  • Fast availability
  • Modular design principle




  • Lime and cement industry
  • Powders
  • Fertilizers
  • Minerals etc.
  • Suitable for transporting hot material (up to 1000°C)

FLENDER Gear units for belt conveyors


In open-cast mining, bulk material often has to be transported over considerable distances. Whereas in the old days this was normally done using trucks, continuous conveyors are the more modern method of choice. The belts can be several kilometers long and more than three meters wide. They operate at speeds that may exceed 7 m/s. Large conveyors are installed in the open, frequently in remote areas with poor access. The gear units have to operate extremely reliably because there is unlikely to be any cooling water available on site. Moreover, the material frequently needs transporting upward or downward to different heights.


FLENDER gear units are supplied with an air-oil cooler or an enlarged housing surface if high working temperatures are expected. Depending on the operating conditions, they are fitted with backstops or brakes to prevent the belt from traveling backwards – and the load from falling off the conveyor – when the drive is switched off.


Technical data


Types Helical and bevel helical gear units
Sizes 22
Gear stages 2 and 3-stage
Power ratings up to 4,500 kW
Transmission ratios i = 5 to 9
Nominal torques 6.2 to 900 kNm
Mounting positions horizontal




  • High operational reliability
  • High thermal capacity
  • Large housing surface
  • Forced lubrication by flanged-on pump
  • Reinforced bearings
  • Coupling flange
  • Low noise level
  • High efficiencies




Belt conveyors

FLENDER Gear units for aerators


An aerator is an impeller in the biological part of a sewage treatment plant. It swirls the surface of the water so that it is enriched with oxygen. This activates the bacteria, so that the biodegradable constituents are removed from the sludge.


The impeller is fixed to the gear unit output shaft, which is extended vertically downward, a certain distance from the gear unit. To prevent the clarified water from becoming contaminated with gear oil, FLENDER gear units are designed with an output shaft featuring an oil retaining tube and a non-contacting, non-wearing shaft seal.


The axial and lateral loads resulting from the process are absorbed by extra-heavy-duty output shafts and output bearings.


Technical data
Types Helical and bevel helical gear units
Sizes 16
Gear stages 2- and 3-stage
Power ratings up to 3,600 kW
Transmission ratios i = 6.3 to 112
Nominal torques 10,5 to 173 kNm
Mounting positions vertical




  • Oil pressure lubrication with flanged-on pump
  • Reinforced bearings
  • Dry well design (shaft seal is absolutely oil-tight)
  • Coupling flange for mounting the aerator
  • High operational reliability
  • Low noise level
  • High efficiencies




Wastewater treatment

FLENDER Gear units for reactors


The term "reactor" is used in the chemical industry to refer to special apparatus (e.g. a stirred tank reactor) in which educts are reacted to obtain a desired product.


The reactors for this kind of application are designed to meet very high process and safety standards.


Powders and suspensions such as pastes, doughs etc. are dried in a mixer-dryer-reactor. The drying process that takes place inside the reactor is often required to be rapid yet simultaneously gentle on the product.


The gear units must therefore have a very high efficiency and produce only minimal vibration and noise. It should also be possible to monitor the complete gear unit.


Technical data
Types Helical gear unit
Sizes 28
Gear stages 2-, 3- and 4-stage
Power ratings up to 10,500 kW
Transmission ratios i = 6.3 to 450
Nominal torques 5.8 to 1,400 kNm
Mounting positions horizontal and vertical




  • High efficiency
  • Minimal vibration
  • Low noise level
  • Dip lubrication
  • Complete drive solution mounted on a baseframe, comprising:
    • Motor
    • Input coupling (FLUDEX)
    • Gear unit, incl. monitors
    • Gear coupling on output side




Drying / mixing chemical substances as well as food products of all kinds

FLENDER Gear units for crushers


Crushers reduce the size of the coarse pieces from the mine in one or more processing stages so that they can be ground in mills. Crushers operate with pressure or impact, and they exist in stationary and mobile versions. For the Siemens FLENDER gear units for crushers, EURO-TECH draws on its modular standard products, which have been tried and tested thousands of times and are readily available.


Technical data


  • Planetary gear unit
  • Nominal output torque from 22,000 to 2,600,000 Nm (higher torque on request)
  • Ratios from 25 to 125




  • Compact, space-saving design
  • Everything from a single source: Gear units, torque reaction arm system, couplings, and oil supply systems can be supplied ready for installation
  • Worldwide service




  • Cement industry
  • Mining

FLENDER Gear units for wet cooling towers


The trickling of water in wet cooling towers is selectively controlled by the cooling tower drive. Usually two-stage bevel-helical gear units are used in addition to the motor. FLENDER gear units are specially designed for use in wet and hybrid cooling towers. As a major design criterion, the fan speed is optimized by using the most diverse transmission ratios. If any special transmission ratios are needed, these can also be provided. The resulting reactive forces of the fan can be absorbed directly by the gear unit.


As the motor is situated outside the cooling tower, the gear unit located in the middle is driven externally by a long composite coupling which is also included in the FLENDER product portfolio.


Technical Data
Types Bevel helical gear unit
Sizes 14
Gear stages 2-stage
Power ratings up to 2,000 kW
Transmission ratios i = 5 to 22.4
Nominal torques 3,000 to 97,500 Nm
Mounting positions vertical


  • Low noise emission thanks to torsionally rigid housing
  • Variable lengths of output bearing arrangements for various fans (adapted to the fan profile)
  • Maximum operational reliability through solid housing, bearing reinforcement, grease slinger on the fan shaft
  • Additional cooling by fan on the input shaft
  • Long service life thanks to optimized design and use of high-quality materials
  • Complete drive train from a single source


Power generation industry, for example:

  • Biomass power plants
  • Gas-fired power plants
  • Nuclear power plants
  • Coal-fired power plants
  • Waste incineration plants
  • Oil-fired power plants

FLENDER Gear units for water screw pumps


Water screw pumps rotate in an open concrete trough and are used to lift water in sewage treatment and drainage plants.


The screw works according to the Archimedes principle and is inclined at an angle of approximately 38°. Archimedean screw pumps are suitable for pumping heavily contaminated liquids, even those containing small solid particles. The delivery head is normally only a few meters and the flow rate relatively high.


The output shaft of the gear unit, whose mounting position corresponds to the inclination angle of the screw, does not absorb any additional loads and transmits the torque to the worm shaft by means of a flexible coupling.


FLENDER gear units are specially designed to operate in these conditions. They need an adjusted oil level, a suitable shaft seal, an oil drain, and an air vent for this purpose.


Each gear unit is fitted with a backstop to prevent the screw from accelerating backwards by the water that is forced back when the motor is switched off.


Technical data
Types Helical gear unit
Sizes 28
Gear stages 2-, 3- and 4-stage
Power ratings up to 10,500 kW
Transmission ratios i = 6.3 to 450
Nominal torques 5.8 to 1,400 kNm
Mounting positions Inclined position 30 to 38°




  • Low noise level
  • Minimal vibration
  • High efficiency
  • Integrated package solution
    • Mounted on a baseframe
    • Backstop included
    • Coupling protected by guard
  • Monitoring supported
  • Dip lubrication




  • Municipal sewage treatment plants
  • Drainage plants
  • Irrigation systems
  • All applications where water has to be lifted to a higher level

FLENDER Gear units for sugar mills


FLENDER gear units are used in the manufacturing process of sugar from sugar beet and sugar cane and contribute to saving energy through their optimized design. Carefully planned drive systems are designed to save space.


For mill drives, the core of the sugarcane industry, EURO-TECH provides load-sharing Siemens FLENDER DUORED 2 gear units, for example, and low-speed PLANUREX planetary gear units are used for diffuser drives. FLENDER gear units are also found on conveyor belts, crushing machines, and turbines used to generate electricity.


FLENDER gear units are also used in sugar production from sugar beet. For example, each pulp press is equipped with up to eight FLENDER planetary gear units (PLANUREX), but also frequency-controlled FLENDER gear units are used for the counter-current beet cossettes macerator, and MOTOX-N geared motors are used in the extraction plant..


Technical Data


  • Type: DUORED
  • Sizes: from 550 to 1200
  • Power rating: up to 9,740 kW
  • Ratios: i = from 18 to 900
  • Nominal torque: from 550 to 4,800 kNm




  • Design optimized for energy savings
  • Noise-optimized
  • Space-saving design
  • Highest efficiency with favorable temperature behavior
  • Worldwide service




Processing of sugar beet and cane

FLENDER Gear units for rotary kilns


The rotary kiln is the core of lime and cement clinker production. In the slightly inclined cylindrical tube, which rotates around its longitudinal axis during the firing process, the lime powder is heated up to 1450 °C and burned into cement clinker. The rotation has both a transport and an air injection effect. The length of such a kiln can be well over 100 meters. In this type of kiln, the limestone is added at the slightly higher end and slowly passes through the kiln due to the rotation. All drive elements must also be inclined accordingly. EURO-TECH offers the latest Siemens FLENDER drive systems for rotary kilns: frequency controlled electric motors, FLENDER helical, bevel helical, and planetary gear units, FLENDER auxiliary gear units with integral overrunning clutch and centrifugal brake, holding brake, auxiliary motor, and FLENDER couplings.


Suitable FLENDER gear unit types


  • FLENDER gear units
  • FLENDER planetary gear units


Advantages of FLENDER planetary gear units


  • Compact, space-saving design
  • Auxiliary drive mounted on the side of the main gear unit
  • Gear units, torque reaction arm system, motors, couplings, brakes, oil supply systems are supplied ready for installation (everything from a single source)




Lime and cement industry

FLENDER Gear units for tube mills


With a power requirement of up to 30 MW, tube mills belong to the largest driven machines. They crush minerals, ores, coal, or cement clinker by impact and friction until the material is pulverized. The tube mills, which can have a diameter of up to 15 m and a length of up to 20 m, are installed horizontally.


With tube mills, a distinction is made between different drive variants. Siemens particularly specializes in:


  • Single pinion drives
  • Central drives
  • Load sharing girth gear units


For all three variants, Siemens offers the entire drive system: Motor, gear unit, couplings, pinion, and girth gear, as well as auxiliary drive, safety devices, and diagnostic systems.

FLENDER Gear units for ships


Consistent industry orientation, leading technology, international production sites, and worldwide service – we put our strengths to work for our customers. Between the engine and the propelling screw there are therefore economically designed drive and system solutions with maximum reliability, minimal maintenance costs, and optimum efficiency.


Under the NAVILUS name, Siemens offers all types of Flender marine gearboxes with power ratings of up to 50,000 kW.

FLENDER Gear units for vertical mills


Vertical mills (such as bowl, roller grinding, ball-and-ring, and roller mills) are mainly used for comminuting limestone, clinker, slag, lime, gypsum, and ores for the building industry, and coal in the coal preparation. They reduce raw material from a thickness of 30 mm to a very fine-grained material. The pulverizing of mineral raw materials is an extraordinarily energy-consuming process. To make processes economically efficient, the power transmission equipment to be used must be adapted to the specific requirements of the preparation process.

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