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COMPANY NEWS China boosts Swedish ventilation order books Jun 2011
GIA News Release
Record breaking orders from China have boosted the order books of Sweden's specialist ventilation manufacturer GIA Industri AB. More than 30 Swedvent ventilation fans and ducting worth more than €3 million, have been ordered by Chinese contractors for tunnelling projects in China and Vietnam.
Four AVH125 units for Vietnam

Four AVH125 units for Vietnam

In its largest single Chinese order, GIA will deliver a total of 16 Swedvent fans for the Huangdao Underground Petrol Storage project in Qingdao. The order is placed by Wujing Hydro Power Corporation through the Shanghai-based GIA China office and comprises four AVH90 units, three AVH140s and nine AVH180s. The installation will meet the ventilation demands throughout tunnel excavations of more than 3.6 million m3/min and is considered to be the country's largest underground construction ventilation installation to date.
In a second project, 12 fans will be supplied to the Nan Lvliang Rail Tunnel Project in Puxian, Shanxi Province. Four complete fan stations, each comprising two AVH180 fans and two stations featuring two AVH160 units, will be supplied to CRTG, one of China's leading contractors for railway projects.
According to GIA China's Regional Manager, Cui Guangcai, this order represents an important milestone for the company. "In the past Chinese contractors have relied on lower cost locally-built ventilation systems more suited for shorter tunnels. Similarly, as a result of the tunnel lengths, GIA will also supply more than 10.8km of its ventilation ducting with a 2.2m diameter for this project."
"Further" he explained, "GIA has made an important move into the Chinese Metro projects where contractors once again have preferred lower cost domestically produced fans." The significant exception is the Chongqing Metro Line 6 with GIA winning another breakthrough order from Bureau 18 CRCC. Comprising two fan stations, each with a AVH90 fan, the order also includes 7,000m of 1200mm GIA ducting. Phase 1 of the project, due for completion in 2013, features a total 23.6km of running tunnels and 12 stations between Lijia and Xinjie.
GIA Shanghai will also supply Bureau 18 with 2,000m of 2.2m diameter ducting and a GIA locomotive system for one of the twin tubes of the West Qinling railway tunnel project. Bureau 18 has also placed an order for a complete fan station comprising four AVH125 Swedvent fans for its Thuong Kon Khum hydro project tunnelling contract in Vietnam.
Portal vent station installation in Vietnam

Portal vent station installation in Vietnam

Recent developments
The new generation of Swedvent fans features improved silencer design to provide noise reductions of at least 3 dB(A) for the full range of fan motors rated between 10kW and 500kW to meet 75–85 dB(A) at 7m. The improved sound damping has been achieved with a specially designed silencer filled with processed mineral wool to reduce high frequency sounds.
An advanced impeller design incorporates a large hub, short blades and accurately measured spacing between the blades to give the fan an enhanced ability to counteract high pressure systems. The dynamically balanced impeller rotates in purpose-designed guide vanes to eliminate turbulence.
Individually adjustable aluminium blades allow the same fan to be used for a number of different tunnel conditions. By adjusting the blade angle, a 1,250mm diameter fan, for example, can be set to deliver 16m3/sec–44m3/sec. The range of Swedvent fans is available with 630mm-2,240mm diameters and 1.5m3/sec–200m3/sec capacities.
Fans in the GIA Swedvent range are particularly suited to long tunnels, allowing two or more fans to be installed in series and thereby offering increased power to counteract the possibility of high pressures in the tunnel ducting.
References
Chongqing Metro tunnelling - TunnelTalk, Jan 2011

           

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