Above: Torque tightening of clamping connection nuts and belt clamping finished
ACC Cement Ltd (Holcim Group) has commissioned AUMUND Engineering Pvt Ltd, Chennai/India, with the refurbishment of the tallest belt bucket elevator in the world, which is 175.3 m high. The elevator is installed at Wadi Cement, one of the largest and most modern cement plants in India, for raw meal pre-heater transport at a continuous rate of 600 t/h. The project is an excellent example of the AUMUND Group rebuild and refurbishment service.
Whilst the machine at Wadi Cement in the Indian state of Karnataka remained in service, a detailed inspection revealed complete overhauling would soon be required and the company decided to invite bids for the supply and supervision of installation of the necessary components on a time bound schedule preventative maintenance. After due deliberation and looking at performance of various elevators operating at their plant, Holcim decided to award the contract to AUMUND.
Originally, the machine was fitted with a steel cord belt of width 1,320mm and tension rating of 3,150 N/mm. After passing the application data through sophisticated computerized selection programme, AUMUND decided to offer an alternative based on its own design concept resulting in a belt width of 1,300 mm but with higher tension rating of 4,000 N/mm with a bucket size of 1,250 mm at bucket spacing of 450 mm.
Improved directional stability and better tracking of belt
The AUMUND belt concept envisage continuous close pitch longitudinal ropes without rope free bucket mounting spaces but with additional wire ropes running laterally across the width of the belt adding considerable lateral stiffness without significantly changing the belt longitudinal flexibility. This cross-stabilized construction gives improved stability to the belt with improved bucket fixing. This help to avoid the most common cause of elevator failure, which happens at the area of bucket fixing. AUMUND design impart improved directional stability and better tracking of belt.
To make the necessary belt punching, AUMUND has developed a special punching machine design which gives clean fixing holes accurately aligned relative to the belt edge and at precisely the correct pitch. The belt is held in a cassette and advanced automatically under the punching frame using a precision encoder to measure the pitch. The belts are prepared at the AUMUND production in Rheinberg, Germany, and shipped to site at the exact required dimensions including a prepared joint and the required clamping connection.
In addition to the new belt the elevator will be fitted with new drive pulley including friction linings and rubber bucket mounting strips. The casings, inlet and outlet plus the complete drive unit remain unchanged.
AUMUND conversion and replacement service
The conversion or replacement of existing AUMUND conveying equipment, as well as non-AUMUND equipment has been an integral part of the technological expertise of the AUMUND Group for more than 30 years. AUMUND offers the service across the equipment range including belt and chain elevators, pan and bucket conveyors plus plate feeders. A refurbished machine can be supplied with all new moving parts by AUMUND retaining often only the structural elements resulting in a new machine with typically a substantial cost reduction compared to outright replacement. With minimum changes to the structural parts and chute works installation time is significantly reduced and machines may generally be upgraded to the AUMUND standard during a scheduled stoppage. Of course once upgraded in this way the client can expect the usual AUMUND dependability and access to service support and genuine AUMUND spare parts. At the same time AUMUND can offer the possibility of plant capacity improvement with minimum investment.