Pakistan’s Water and Power Development Authority (WAPDA) ordered no fewer that three XL type hydraulic trash rack cleaning machines (TRCMs) from Muhr GmbH.

The large-scale contract comprised the delivery and installation of TRCMs for the Chashma and Jinnah facilities on the River Indus, and the Warsak plant on the River Kabul. The almost identical HYDRONIC M-4500 KT TRCMs used in the hydropower plant on the Indus were already inaugurated at the end of 2015; the installation of the HYDRONIC M-5000 KT at the Warsak plant is about to commence.

The biggest challenge in implementing these projects, says Florian Kufner from Muhr, was the logistics behind it: „From shipping the TRCMs to clearing them through customs and transporting them to the installation, to organising the cranes and tools and completing the final installation – every single step had to be coordinated on schedule. What helped us a great deal was our extensive experience with similar projects, for example, in India, Malaysia, and Laos. Working on-site with our customer allowed us to keep the project on track, especially where administration and documentation were concerned.” Florian Kufner also commends the hospitality and teamwork of the customer’s team, who were highly satisfied with the quality of the machines and the operational concept. Both projects were completed, accepted and delivered precisely as planned and scheduled; the team was even able to finish the final installation ahead of schedule. The TRCMs’ cleaning performance even exceeded WAPDA’s expectations, establishing a solid basis for further projects in the future.

THREE FACILITIES, THREE VERSIONS
Hydropower plants Jinnah and Chashma are situated on the River Indus, the longest river on the Indian subcontinent, in the Pakistani province of Mianwhali. At both sites, the installation of the new TRCM was combined with performance improving work on the power generating facilities. The TRCMs of type HYDRONIC M-4500 KT that were installed at Chashma have a cleaning range of 25,5 m, a track-based travel range of 151 m, and a weight of 90 tonnes when fully assembled. At the Jinnah plant, the same TRCM model is used, although this one has a cleaning range of 24,1 m and a travel range of 195 m. The TRCM to be installed at hydropower plant Warsak on the River Kabul will be a HYDRONIC 5000 KT with a 27,5 m cleaning range and a weight of around 115 tonnes. It will run on a curved track system. All TRCMs run on tracks, and all are equipped with a telescopic swivel arm. The machine at the Warsak plant is also rotatable. Further-more, all three trash rack cleaners are equipped with a „Vario Cleaning Head”, which enables the use of orange peel grabs and sediment grabs in addition to the usual cleaning rake.

PRECISELY TAILORED CONSTRUCTION
The existing machines at the Chashma and Jinnah plants underwent a significant redesign. For example, the narrow width of the existing track system required sophisticated weight balancing adjustments to maintain operational stability. Due to the static conditions at the intake structure, the TRCM’s weight had to be kept below a specific critical value. Also, the machines’ maximum design height and width was limited by the size of the portal crane. Further size limitations were imposed by the height of the portal chassis. These limits had to be taken into consideration to avoid interference with the existing debris tipper. A special construction was installed between the chassis support structure to accommodate the tipper.

STRAIGHT TRCM PERFORMANCE ON A CURVED TRACK
In addition to the vertically aligned trash rack at the inlet, the TRCM at hydropower plant Warsak can also clean the horizontal trash rack in the upstream area. „To make this possible, it was necessary to reinforce the machine’s static design and increase its performance. Another special feature is the strongly curved track line that the TRCM runs on. This required a specially constructed chassis,” as Florian Kufner explains. The machines are also equipped with a system for hoisting and lowering the power plants’ stop logs and trash rack screens if necessary. Collected debris is dumped by the TRCM into a preinstalled container behind the machine.

CONTRIBUTING TO A SUSTAINED ENERGY SUPPLY
Pakistan is still considered a developing country. Due to so-called „load shedding”, power outages are an almost daily occurrence all over the country. This is the result of the extreme nation-wide power shortage, as the power supply of an entire province may be disconnected from time to time without prior notice and switched over to another province. Accordingly, WAPDA’s future plans call for the continuous improvement of the nation’s energy supply. This is why projects dedicated to improving the energy supply situation receive a lot of public attention. Judging by the customer’s satisfaction, Muhr is likely to continue contributing to Pakistan’s energy security in the future.