Advertorial: KELLER rock the waves

By Marcel Wiegman,
Managing Director at C.U.W. Keller Gmbh & Co.Kg

Customer approval in powertrain technology depends specifically and to a great extent on the reliability and robustness of the facilities and in particular on their individual components. These include first and foremost the gearbox and gear wheels of the specialist transmission manufacturer, C. u. W Keller GmbH & Co.KG (KELLER).

The high customer requirements can be met by the custom made gearbox manufacturer Keller with its experience in the design and manufacture of gear wheels and gearbox that spans more than 100 years.

In the past, individual parts as well as gear units for steel manufacturing and mining comprised the key components of sales planning. In addition to the traditional gearing applications for sugar presses and rubber kneaders, gear units for marine applications were added to the list 18 years ago.

KELLER has become a leading gearbox manufacturer in the premier league of marine gearbox suppliers. In certain niches like the dredging industry, KELLER even stands at the No. 1 position, National and International.

As said, it all started some 18 years ago. KELLER started with the repair of some marine gearboxes for propulsion, cutters etc. Soon being followed by the first, own designed, gear units for fishing- and smaller cargo vessels. In the late year 2000 however KELLER was requested to supply a large gear wheel with a Diameter of 2,200 mm for the Hopper Dredger “Lange Wapper” of Belgium´s major Dredging Company DEME. The gear wheel which was a replacement for a competitor propulsion gearbox had to be supplied with the shortest delivery time thinkable as the vessel was, due to the gearbox breakdown, laid up in Hong Kong. The gear wheel was supplied within 5 weeks, which was a third of the original quoted delivery time of the gearbox manufacturer.

The KELLER´s sensational delivery time was the best thinkable advertisement for a newcomer on the market, resulting in serious interest by all major dredging companies. This again resulted in a for KELLER major market share for gearboxes in the dredging industry. Since that time KELLER supplied some 300 gearboxes for 120 dredging vessels. These include gearboxes for:

• Cutter heads
• Dredge pumps
• Propulsion
• Generators
• Winches

After the first steps on the way of being successful, KELLER realized very soon, as gearboxes for the dredging industry became bigger and bigger, the production capacities at KELLER had to follow those steps. Large investment programs were set up.

The first in the period of 2007 – 2009 where KELLER bought several new production machines, e.g. a mill for the machining of gearbox housings up to a weight of approx. 100,000 kg and the largest gear grinder in Germany for gears up to 4,150 mm Diameter.

The second investment wave came in 2015, were among others a gear cutting machine was installed for gears up to 4,700 mm Diameter. The total investments over the past 15 years succeeded a total amount of € 35 million.

As KELLER is a company that grew up with industrial applications, the need for specialized engineers with experience in marine applications grew by the day. It was therefore needed that besides of some “fresh blood” the existing engineers were trained very intensively by the senior engineers. Al of this was professionally mastered in a sooner than expected time frame.

As not only the gearboxes, but also the projects became bigger and bigger it also became clear that project teams consisting of a dozen engineers needed to be entrusted with the tasks and questions concerning development, manufacture and assembly, as well as the ensuing logistics. KELLER excels in the manufacturing of large gear wheels and its expertise in the impact of heat treatment on the quality of the component parts in particular is just one of its core competencies.

During the design and manufacturing phase, project meetings take place regularly during which all internal processes including sometimes special required transportation are discussed. By doing this, the required quality as well as the tight time schedule has to be maintained at all times.

An essential component of the quality control is conveyed to the final test run. Drive and gear mechanisms are put through their paces. Support images of the gear toothing are taken and these are then compared with the calculations; the noises and vibrations are measured and the transmission tightness verified. In addition, the bearing temperatures are recorded over a period of several hours.

Especially in the Dredging industry, is engineering the word. Certain dredge applications look very simple and it can easily be thought that there is nothing particular behind it. Until the moment one gets familiar with the application. For example, in addition to the classic bearing, shaft and interlocking calculation, comprehensive research has sometimes to be carried out on the deformation and stress behaviour of shafts and the gear-casing structure using FEM.

Pinion shaft
Planet carrier

This will e.g. be conducted with the aim of optimising the casing structure due to the immense and additional changing loads that can occur during the dredging process. KELLER’s years of experience in the deformation behaviour and the stiffness ratios of the conductor structures on which e.g. a cutter-head drive is installed carried its weight in this consideration. The deformation behaviour not only affects the structural load but also impacts the smooth operation of gears and bearings significantly. Thus, these findings are also taken into account in the determination of the tooth-contact-stress levels in the tooth engagement.

To this end, KELLER, as long-standing member of the Research Association for Drive Technology in Germany (“FVA”), uses e.g. the RIKOR programme of FVA, which enjoys a firm standing and recognition over the years in such construction processes.

The success story is not ended yet.

KELLER supplied gearboxes for the largest hopper dredger ever build in the Netherlands, the “Vox Maxima” of the Dutch Dredging company van Oord with e.g. 2 propulsion gearboxes of 15,000 kW each and each with a generator PTO of 10,000 kW.

In 2015 KELLER received a purchase order for the supply of a 5000 kW cutter gearbox for the largest Cutter ever build in China, the “Tian Kun” of TDC. With the delivery of the gearboxes, KELLER also supplied the complete electrical monitoring control system of the gearboxes.

In 2016 KELLER was selected by the Belgium dredging company DEME as the supplier of the majority of the gearboxes for the largest suction cutter dredger on earth, the “Spartacus”. The cutter gearbox to be supplied by KELLER is the largest gearbox in the dredging industry and in case hardened and ground design probably in general the largest worldwide.

There are certain voices that say:
„He who sows the wind shall reap the whirlwind“

The reputation KELLER builds up in the dredging industry also found its way for Merchant Navy vessels. Several dredging companies provided KELLER with recommendation letters not only concerning the new built gearboxes, but also in respect of the after sales service provided. Here KELLER was for example requested to repair, replace or upgrade existing gearboxes supplied by third parties. Soon KELLER was contacted and requested to offer different type and sizes of propulsion gearboxes. Within in a very short period, KELLER supplied propulsion gearboxes for general cargo vessels, chemical tankers and passenger ships.

Although the 2 stroke engine is having an unknown revival, propulsion gearboxes are still needed.

The present tendency for 2- stroke instead of 4- stroke engines results oft in a gearless drive system. Electric driven propulsion systems are also getting more and more popular. It is for that reason that KELLER also has developed a special gear drive system for LNG carriers. Further you will find in the KELLER portfolio so- called shaft or tunnel generator gearboxes.

The success of KELLER was based on several factors like e.g. personnel engagement, quality and last but not least, it´s high engineering standard.

It is in practice the combination of state of the Art production, engineering’s- and application know-how that counts for a high quality product and a satisfied customer.


Disclosure: This article is paid for and produced by C.U.W. Keller Gmbh & Co.Kg and does not necessarily reflect the view of DredgingToday.com. No member of the editorial team took part in creation of this advertorial.
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