ÿÈÕ³Ô¹Ï

Valmont is a world-renowned company that manufactures street lighting poles, traffic signal poles, utility poles, communication poles and poles to light up large sports complexes and stadiums, with manufacturing locations spread around the world. In India, Valmont has a large manufacturing plant at Indapur (Maharashtra). The plant is designed to facilitate a linear flow of material right from the entry of the raw material to the finished product at the despatch bay. The plant is equipped with state-of-the-art manufacturing equipment.

The handling challenges at Valmont
Valmont needed cranes to integrate handling right from the entry of raw material to the final stage of processing and despatch. At the beginning of the manufacturing process, in the steel yard the pole stacks are required to be lifted and placed onto the conveyors at the entrance of the fabrication shed/bay. This necessitated lifting and then rotating of poles by 90 degree. Conventional cranes pose a limitation in rotating the poles automatically and placing them precisely on the conveyors. This made the handling requirement from the EOT crane in this area the most challenging.

Solutions from ElectroMech
At Valmont, ElectroMech installed a total of 22 cranes throughout their manufacturing plant at several locations performing different applications. These cranes are being used at various stages in manufacturing, right from the unloading and carriage of steel poles from the steel yard to placing the poles on the conveyor for fabrication, followed by a galvanisation process and then to the final despatch yard. The cranes used in the main manufacturing bays are of standard configurations and are used for performing rigorous applications. There are cranes installed in five different bays at Valmont which include the steel yard, fabrication bays, stores, galvanising bay and despatch area. Twenty cranes are installed in the indoor area while two cranes are operated in the outdoor which consist of one 10/10MT single girder crane at the despatch area while the other 10/10MT double girder crane with a rotating crab between the steel yard and the fabrication bays. The fabrication shed consists of a combination of 13 cranes of different types and capacities altogether, ranging from 5/5MT to 8/8MT with the span of 17.6 m to 23.46 m of double girder and Jib Cranes. One single girder crane of 5MT capacity with a span of 10.5 m is operated in the stores area, while six double girder cranes of 16MT capacity with 24 metres span are installed in the galvanising plant, where the steel poles undergo Seven Tank Galvanising process.

Special crane for Valmont?s distinctive application
The engineering team at ElectroMech analysed the conditions and designed an innovative and cost-effective material handling equipment for the steel yard. Using a conventional EOT crane was ruled out because rotating the poles would have been a cumbersome process, involving manual intervention to do the job. Considering this aspect, engineers from ElectroMech designed a special crane with a rotating crab. This innovative design permitted extreme flexibility and ease of work. This one of its kind rotating crab is capable of rotating the object by 360 degree in clockwise or anticlockwise motion. The special design consists of two hoists of 10MT capacity each, mounted on a rotating crab of a double girder crane. The span of the crane is 17.6 m and the height of lift is 7.6 m. It can lift a load up to 20MT. The steel poles from the steel yard are lifted using this special purpose crane, turned by 90 degree to bring them in line with the conveyor in the fabrication bay and then carefully placed on the conveyor. Here, the steel poles are bifurcated into large poles and small poles according to their diameter sizes and then transferred to the respective fabrication bays. This ingeniously designed system resulted in a tremendous amount of saving in labour, time and enhanced productivity at Valmont.

Challenges

• Integration of handling in the entire plant
• Rotation of 15 m to 18 m long poles through 90 degree for placing onto the fabrication conveyors
• Ensure safety while handling long poles
• Achieve economy through optimum design of cranes

Solutions

• Recommended use of 22 cranes while taking into consideration the material flow
• Specially designed rotating crab allows rotation of poles through 360 degree
• Cranes which ensure high levels of safety
• Reduced project cost and time due to indigenous development

How Valmont benefited from ElectroMech solution

• Swift, precise and easy placements onto the conveyors
• High level of safety is ensured
• Reduced project cost due to indigenous solution

Other similar applications of rotating crab

• Cranes of similar design with newer concepts are being used at a leading steel plant. There, the slewing bearings and slewing wheels are used to achieve rotation of the crab.
• The application can be extended to various industries handling a wide spectrum of products such as TMT bars, billets, pipes, etc.
• A similar concept is used in stacker cranes designed and developed by ElectroMech. A stacker crane is a combination of a reach truck and an EOT crane used in warehouses.