Under pressure: tunnelling in groundwater Aerzen Rental establishes itself as a competent partner for preliminary application In Karlsruhe, an underground tram line is being built between Ettlinger Tor and Marktplatz. The tunnel, which is just over 300 metres long and passes through the centre of the city, is challenging because of its special geological formation. To prevent water penetrating into the construction site, the company Pressluft Frankfurt Drucklufttechnik GmbH relies on our compressor technology. In Karlsruhe, the eight CVO4400 units of Aerzen Rental are combined into two-storey units to save space. Anyone who stands on Karl-Fried-rich-Straße in Karlsruhe during a downpour and takes a look at the asphalt will notice a fine-pearled foaming road. The reason: the tunnel underneath, with its base 15 metres below street level, loses air. “Here, we have to deal with a lot of sand, gravel and loose rock. These are materials which are not useful in tunnel construction,” says Robert Schweitzer, Construction Manager, describing the challenges he faces in the centre of Karlsruhe. On one side, due to the geological conditions, BeMo Tunnelling GmbH is forced to stabilise the walls by propelling shotcrete at them, as otherwise the ground could behave unpredictably. On the other side, the pores are so large that the ground water would run directly out of the walls if the appropriate counterpressure is not provided on site. This leads to the conclusion that the work is literally under pressure. In the first construction phase, this is at a delta of 0.75 to 0.85 bar to the atmosphere. Therefore, the project is subject to German compressed-air regulations which define the relevant rules regarding job safety. Against this background, nobody is permitted to enter the pressure lock without a special briefing - and must not leave it without decompression taking place. The pressure sluice supplies data to a control room where the sluice monitor always has an overview of the operating status of all compressors on a display. Twelve assemblies are installed - four underground and eight on the road directly above. The spatial division is due to the fact that soil analyses undertaken at the beginning of the tunnel project suggested a higher degree of impermeability. This assessment subsequently proved incorrect and thus the flow capacity which had been calculated for the compressors did not apply either. “Making forecasts for old riverbeds is almost impossible.” We simply do not know what to expect”, says Peter Engelke, project manager of Pressluft Frankfurt. The company received an order from BeMo to design the compressed air according to the initial soil analysis in the Rhine plain.Efficient and quickly available solutionFour compressors - initially provided for underground work - are not sufficient to reliably prevent the groundwater from penetrating, due to the sandy soil.As it soon became clear that the calculated performance would not be sufficient, Pressluft Frankfurt and Aerzen Rental started looking for an efficient solution that would be quickly available. “The cooperation between all three companies is quite flexible and very professional”, emphasises Engelke. “We have integrated the compressors with Delta Screw packages (VM 60, 1.140 to 4.550 m³/h, 45 to 250 kW) as core within container frames. These can be easily transported, combined to form space-saving units on site and, thanks to the cartridge design, can also be stacked on top of each other,” explains Peter Link who is responsible for the German rental business. The headquarters of Aerzen Rental is at Duiven in the Netherlands. In Karlsruhe, the compressors type CVO4400 are combined with water coolers which cool down the air outlet temperature of the compressor from 120°C to 20°C. Efficient reserves are requiredDuring the not so deep work, the assemblies pump 100 to 140 cubic metres of air per minute into the tunnel on a daily average. This also explains the foaming road when it rains. The deeper the site is, the more the pressure increases from the groundwater. Robert Schweitzer expects a pressure delta of up to 1.3 bar by the end of the structural work. Therefore, the pressure losses will increase exponentially and a higher volume flow will be required. For this reason, and according to the compressed air regulations after sufficient redundancy, the equipment supplied by Aerzen Rental covers adequate reserves. “We have to cover the complete demand by two thirds of the installed machine performance. Four of the twelve assemblies serve as spare machines”, explains the mechanical engineer. “The specific performance of the assemblies is unrivalled,” emphasises Engelke, describing the start of cooperation between AERZEN and Pressluft Frankfurt more than 30 years ago. “In all these years, I have never had a broken machine - this signifies long working life and reliability.” In Karlsruhe, the speed of the compressors is adjusted so that their actual performance corresponds exactly with the pressure losses from the tunnel - these measure 15,000 cubic metres from Marktplatz to Ettlinger Tor. In addition, it is economical for BeMo Tunnelling and Pressluft Frankfurt to rent these compressor packages in such special application cases, instead of buying them. And the independent Aerzen Rental service takes care of all the maintenance during the time that the equipment is in operation.
Five years of AERZEN Turbo Aerzen Turbo in Korea had a double anniversary this year, marking: five years in existence and five years of production – definitely a cause for celebration. At the beginning of December, all employees, as well as Vice President Asia Pacific - Chuck Lim, Product Manager Turbo - Steffen Helmert, Vice President Marketing & Product Management/Director Turbo Business - Stephan Brand, as well as H.J. Lee and C.Y. Kim of the local representative HC Corporation, were invited to a joint Company Dinner. As part of the celebrations, other anniversaries were honoured: 17 of the 58 employees of Aerzen Turbo have been present since the day the company opened.Aerzen Turbo has been producing the core components of AERZEN Turbo Blowers – Turbo stage, frequency converter and control unit, as well as complete packaged units. Turnover has increased to more than EUR 8 million over the last five years.
Application managers for Europe, Middle East and Africa In January 2016, Markus Leidinger took over the new function of Application Manager Wastewater Treatment Plant for the Europe, Middle East and Africa regions. He had previously worked for nine years as a sales engineer in our sales office South-West. In his role he gained a considerable amount of practical experience, particularly as far as applications around sewage treatment plant technology are concerned.
First internal system audit completed Since the beginning of 2016 AERZEN has achieved the certifications according to DIN EN ISO 9001 (quality management), 14001 (environment management) and 50001 (energy management), as well as according to OHSAS 18001 (occupational and health protection management system). These certifications are completed by DIN EN ISO 80079-34 (quality management for machines for ATEX-applications), NSQ-100 (quality management for machines for nuclear-applications) and the MID 2014/32/EU module D (quality management for the production of rotary piston gas meters). In September 2016, the quality assurance department has now carried out the first internal system audit for the integrated management system in Aerzen. Successful: All departments fulfil the management requirements.
Meeting of the Customs and Import expert forum The Customs and Import expert forum of the IHK Hanover held a meeting at Aerzener Maschinenfabrik GmbH on 23rd November 2016. After a company presentation, which included a tour of the company premises, the around 40 participants concentrated on the first item on the agenda, the intensification of air safety rules by the Federal Aviation Authority. An exchange of information and opinions on other current topics followed. Topics included the list of goods for external trade statistics with changes for year 2017, the new preferential agreement of the EU with the Ivory Coast and the southern African states, the survey of the IHK Stuttgart regarding supplier’s declarations, and the EU-customs tariff 2017.Further meetings have already been scheduled for 2017 – these will be on 15th February/21st June at Johnson Controls Autobatterie, Hanover, and on 21st September/29th November at Lenze Operations GmbH, Aerzen.
AERZEN Style icon While shopping in Hamburg one of our colleagues discovered an AERZEN product in an unusual place: in the entrance area of the Stilwerk Design centre, in the middle of a café, an old AERZEN blower was exhibited. The GLa 14.18 blower, manufactured in the 1960s, had been running in a malt factory where it had been used in a silo plant.
New manager of Process Gas Division Hungary On 1st September 2016, Dr. Imre Pesthy took over the management of Process Gas Division Hungary from Rolf Heinemeyer. Dr. Pesthy has been awarded a post-graduate degree in metallurgical process engineering, special field metallurgy and welding technology, and completed his Master’s degree in business management. He has long-term experience with leading positions in small and larger production segments of international companies. Besides supporting PGD Hungary further, Rolf Heinemeyer will focus in future on PGD business at AERZEN.
