Liebherr-Werk Nenzing

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Posted in: , on 23. Mar. 2007 - 22:04

Liebherr grab cranes reach not only for the stars

In 2005 the total seaborne trade amounted to 6.6 billion tons, consisting of 39% dry bulk. Therefore four-rope grab cranes for professional bulk handling clearly remain an important part of Liebherr’s strategic focus. Of the 70 mobile harbour cranes sold in 2006, 38 were four-rope cranes for dedicated bulk handling, which represent 54% of the total order intake and reflect the high standard and quality Liebherr costumers can rely on as well as the market leadership in this specific market niche.

Liebherr bulk cranes (LHM bulk version) are available in a wide scope of specific settings. Basically it can be distinguished between two forms of grab operations. On the one hand two-rope solutions using a motor grab and on the other hand four-rope solutions using a mechanical grab. Top selling equipment remains clearly the four-rope version, which implicates not only the cheaper grab but also realises higher turnover. Liebherr mobile harbour grab cranes are designed for a maximum turnover up to 2500 tph depending on crane size, bulk material and working range. Another decisive factor regarding turnover is the size of the grab. Liebherr bulk cranes are able to handle mechanical grabs with a total weight up to 75t and motor grabs with an overall weight up to 90t.

Highest lifetime

The Liebherr grab crane concept as a whole is designed for the highest possible turnover and customer’s benefit. Starting with effectiveness over time Liebherr grab cranes impress with the highest possible lifetime (A8) according to “FEM Design Rules” on the basis of utilization and load spectra. For Liebherr customers the A8 FEM classification means longer service life and a high resale value.

Optimised 4-rope grab control

The perfect load cycle always bearing in mind, Liebherr offers an optimised four-rope grab control as a standard feature. During grab operation, movements of the closing- and hoisting winch as well as slewing and luffing could be driven simultaneously to achieve shortest load cycles. In addition, features as automatic lowering and lifting guarantees an optimal filling level of the grab by current use of its dead weight. The slack rope monitoring takes care of operational reliability and guards against a partial damage of the ropes. Furthermore the traction force of the grab closing winch is automatically controlled to prevent a mechanical overloading of the grab. For another ease of operation and to provide stress-free working conditions for the operator Liebherr offers the “Cycoptronic”® anti-sway system. With this software package higher turnover can be expected for inexperienced crane operators. In addition safety will be enhanced and confidence of operators improves. The same advantages apply to the “Teach In”® feature, a semiautomatic system which pilots exactly to loading- and unloading-point. The driver just has to take control of the speed. Especially when working on hoppers the “Teach In” ® system increases turnover.

Unique fuel saving features of Liebherr

The proven hydraulic drive system in combination with the in-house developed ECO-mode minimizes the diesel consumption during crane operation without any impact on turnover output. Once the designated speed of the crane movement is given, the Litronic® crane control system automatically calculates the minimal required rpm (revolutions per minute) of the diesel engine as well as the necessary pivoting angle of the hydraulic-pumps and -motors to reach the demanded rate. A further advantage compared to diesel-electric drive system is the repeated use of the reverse power (e.g. generated by lowering movements) due to the unique hydraulic power transmission. That means the returning energy can be reused for other crane movements as well as to cover certain basic loads as cooling, main- and auxiliary supply, heating, lighting, air conditioning etc. In comparison, within a diesel-electric drive system the reverse power disappears in resistors. In addition the moment of inertia of a diesel-electric system is approx. 4-5 times higher than a diesel-hydraulic system. This is reflected by the fact that Liebherr’s diesel-hydraulic systems needs less drive power means less fuel and above all shine with a shorter acceleration time.

Drive system totally inured to dust

Bulk turnover is always connected with a high dust exposure. Liebherr bulk cranes are totally inured to all kind of dust, due to the fact that exclusively self-contained components are used. To assure all crane functions no additional air filtering is necessary. The hydraulic oil cooler as well as the engine water and engine charge cooler are situated outside on the roof of the slewing platform (for working conditions over 50°C). Even the necessary ventilation of the machinery house for eduction of the lost heat produced by the diesel engine does not influence availability and operating efficiency at all. Additional filters or exhaust-chimneys according to customer requirements are self-evident. If a very strong dust exposure occurs only an additional cyclone-filter for the diesel-engine is intended. This leads to a reduction of maintenance of the standard air-filters of the diesel engine. But over all these technical improvements stands the fact, that Liebherr technology is absolutely inured to all sort of dust and dirt due to the closed hydraulic system and an electronic system which is military proven and tested.

Advanced robustness

Bulk turnover comprises the handling with aggressive materials. Furthermore the maritime environment implicates highest demands on all materials. Therefore Liebherr mobile harbour cranes are painted corresponding to C5-M / ISO 12944, which is an off-shore and ship crane painting standard assuring highest quality and lifetime under the most adverse, maritime conditions. The machinery house is made of GFRP (glass fibre reinforced plastic), a material unaffected by acid rain and salt water as well as corrosion resistant.

High degree of mobility and flexibility

Liebherr mobile harbour cranes are characterised by outstanding mobility. Due to a system of individual wheel sets (no additional infrastructure e.g. rails or power supply are required) and a very short undercarriage not only narrowest curve radii are possible but also longitudinal and diagonal movements up to 135°. Especially at narrow quays and terminals the above mentioned manoeuvrability is a decisive advantage for the positioning of the crane. Regarding quay load restrictions, which are always a big issue at ports, the modular concept of individual wheel sets allows to reduce the axle loads to the demanded level. During travelling the 3-point suspension guarantees optimum pressure distribution on uneven ground and avoids overloading of the individual wheel sets and of the quay consequently. Also the operational position of the crane can be adapted to the quay requirements on the basis of an X-shaped stabiliser arrangement (quadratic and rectangular support is possible) and different sizes of stabiliser pads depending on the condition of the quay.

Versatility in configuration

Liebherr mobile harbour cranes are multi-purpose machines. Although tuned and customised for grab operations, they can also be used for container and dry bulk handling as well as for heavy lifts by a quick change of the lifting attachment if the need arises to handle different types of cargo.

Constant enhancements and preventive maintenance

Every Liebherr mobile harbour crane is serially equipped with MDR (machine data recording), a recording tool of various crane data used for optimization and further development of structure and components as well as an analysis tool of fatigue life and to establish preventive maintenance.

Low investment costs

A further advantage of mobile harbour cranes is the price range from US$ 2-5m. In comparison STS gantry cranes are situated in a range from US$ 4-9m.

About Liebherr-Werk Nenzing

Liebherr-Werk Nenzing GmbH is part of the Liebherr group presently comprising more than one hundred companies throughout the world and employing more than 22,000 people. Founded by Hans Liebherr in 1949, the Liebherr group is decentrally organised into corporate units of easily manageable size that operate autonomously. The Liebherr Group’s holding company is Liebherr-International AG in Bulle (Switzerland), which is entirely owned by members of the Liebherr family.

Liebherr-Werk Nenzing GmbH was founded in 1976 and concentrates today on the design and manufacture of mobile harbour cranes, reachstackers, ship and offshore cranes as well as duty cycle crawler cranes, lift cranes and foundation equipment. Further manufacturing sites, belonging to the Nenzing plant are located in Sunderland (Great Britain) and Rostock (Germany) as well as four fully owned companies in Hongkong, Hamburg (Germany), Amersfoort (Netherlands) and Niederhergheim (France). A total of approximately 1,700 employees are based at the various sites.

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