Chinese tunnelling contractors place record orders for GIA ventilation fans and ducting
Published 2011-06-30 11:53:13
Record breaking orders from Chinese contractors have been placed for GIA Industri AB ventilation fans and ducting for tunnel projects in China and Vietnam.
Sweden’s GIA Industri AB has won record breaking orders from China for more than 30 Swedvent ventilation fans and ducting worth more than EUR3 million for tunnelling projects in China and 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 – considered to be the country’s largest underground ventilation installation. Placed by Wujing Hydro Power Corporation through the Shanghai-based GIA China office, the complete order comprises 4 x AVH90’s, 3 x AVH140’s and 9 x AVH180’s.
The GIA installation will meet the ventilation demands throughout tunnel excavations of more than 3.6 Mm3.
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 2 x AVH180’s and two stations featuring 2 x AVH160, 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 2.2 m diameter for this project.”
“Further” he explained, “GIA has had little opportunity to also penetrate the Chinese Metro projects with contractors once again preferring lower cost domestic-produced fans.”
An important exception has been the Chongqing Metro Line 6 with GIA winning another breakthrough order from Bureau 18 CRCC. Comprising two fan stations, each with an AVH90 fan, the order also includes 7000m of 1200 mm GIA ducting.
Under Phase 1 of the project will feature a total of 12 stations between Lijia – Xinjie over a distance of 23.6 km: with a completion date of 2013.
GIA Shanghai will also supply Bureau 18 with 2000m of 2.2m dia ducting and a GIA locomotive system for one of the West Qinling projects twin tunnels.
Bureau 18 has also placed an order for a complete fan station comprising four AVH125 Swedvent fans for its Thuong Kon Khum tunnelling contract in Vietnam.
Recent introduction
The recently introduced new generation of Swedvent fans feature improved silencer design to provide noise reductions of at least 3 dB(A) for the full range of fan motors rated between 10 – 500kW to meet 75 – 85 dB(A) at 7 m. The improved sound damping has been achieved with a specially designed silencer filled with processed mineral wool to reduce high frequency sounds.
The ventilation system features advanced impeller design incorporating 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. For example, a 1250 mm dia fan can be set to deliver 16 m³/s – 44 m³/s.
The range of Swedvent fans is available with 630mm - 2240mm diameters and 1.5 m³/s – 200 m³/s capacities.
The fans are built in a rugged anti-corrosion treated design to withstand aggressive environments. The GIA Swedvent range of fans are particularly suited to long tunnels allowing two or more fans to be installed in series offering increased power to counteract the possible high pressures in the tunnel ducting.
