Bäretswil, Switzerland
Bäretswil, Switzerland
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Lusch C.,Karlsruhe Institute of Technology | Borsch M.,WEKA AG | Heidt C.,Karlsruhe Institute of Technology | Magginetti N.,WEKA AG | And 3 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2015

Joints between copper and stainless steel are commonly applied in cryogenic systems. A relatively new and increasingly important method to combine these materials is electron-beam (EB) welding. Typically, welds in cryogenic applications need to withstand a temperature range from 300K down to 4 K, and pressures of several MPa. However, few data are available for classifying EB welds between OFHC copper and 316L stainless steel. A broad test program was conducted in order to qualify this kind of weld. The experiments started with the measurement of the hardness in the weld area. To verify the leak-tightness of the joints, integral helium leak tests at operating pressures of 16MPa were carried out at room and at liquid nitrogen temperature. The tests were followed by destructive tensile tests at room temperature, at liquid nitrogen and at liquid helium temperatures, yielding information on the yield strength and the ultimate tensile strength of the welds at these temperatures. Moreover, nondestructive tensile tests up to the yield strength, i.e. the range in which the weld can be stressed during operation, were performed. Also, the behavior of the weld upon temperature uctuations between room- and liquid nitrogen temperature was tested. The results of the qualification indicate that EB welded joints between OFHC copper and 316L stainless steel are reliable and present an interesting alternative to other technologies such as vacuum brazing or friction welding.

Wesche R.,Ecole Polytechnique Federale de Lausanne | Borsch M.,WEKA AG | Bruzzone P.,Ecole Polytechnique Federale de Lausanne | Holdener F.,WEKA AG | And 6 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2012

High temperature superconductor current leads have been demonstrated to provide cryogenic savings compared to conventional copper leads. The applicability of HTS current leads to industrial fabrication is now a possibility. CRPP and WEKA AG are collaborating in the development of current leads for currents in the range of 3 kA to 30 kA, which are suitable for industrial fabrication. The design of these leads is such that the architecture and construction can be easily scaled to the required current level. The main components of these current leads are an HTS module, a copper heat exchanger, and cold and warm end connections. Two 10 kA prototype current leads, mainly distinguished by different designs of the copper heat exchanger, will be constructed. They will be tested at CRPP to verify the manufacturing processes and the overall design. © 2011 IEEE.

Wesche R.,Ecole Polytechnique Federale de Lausanne | Bruzzone P.,Ecole Polytechnique Federale de Lausanne | March S.,Ecole Polytechnique Federale de Lausanne | Muller C.,Ecole Polytechnique Federale de Lausanne | And 7 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2014

In the framework of a collaboration, CRPP (Centre de Recherches en Physique des Plasmas) and WEKA AG have developed high-temperature superconductor (HTS) current leads for currents in the range of 3 to 30 kA, which are suitable for industrial fabrication. In the development project, two 10 kA HTS current leads, mainly distinguished by the design of the copper heat exchanger and the transition zone between the HTS module and the heat exchanger, have been manufactured by WEKA AG and tested at CRPP. The test of the current leads covered their behavior under normal operating conditions as well as in the case of a loss of flow. Furthermore, a quench of the current leads was initiated by increasing of the helium temperature by means of heaters immediately before the inlet. The measured quench temperatures provide an estimate of the operational limits of the 10 kA HTS current leads. © 2013 IEEE.

Boersch M.,WEKA AG | Holdener F.,WEKA AG | Iten E.,WEKA AG | Oertig D.,WEKA AG
Refrigeration Science and Technology | Year: 2012

Engineering components in cryo-technological plants have to meet demanding requirements derived from functional needs or prescribed in relating standards. For cryogenic components such as cryogenic valves and couplings some of the most important characteristics are defined in tightness requirements and pressure stability. However the performance is needed at service under cryogenic conditions, specific time-tested procedures are established since long time and carried out under ambient temperature level. Whereas for pressure tests it can be followed to the international standards and regulations, the preconditions for definition, testing and interpretation of acceptable leakage rates are based on limits of detectibility of the methods and lastly the experiences in the field. Corresponding specifications and test procedures for test objects to their encircling vacuum insulation, their ambient and their function related pipe connections has been established.

Agency: European Commission | Branch: FP7 | Program: JTI-CP-FCH | Phase: SP1-JTI-FCH.2010.2.5 | Award Amount: 2.12M | Year: 2011

Hydrogen is an important energy carrier as a viable future clean transport fuel. H2-fuelled vehicles are affordable, infrastructure investments are manageable and H2 and electric mobility are required to meet future CO2 emission targets. Plans are made to implement H2-refuelling infrastructure in Germany followed by roll-out over Europe by 2015. Logistically, liquid H2 appears the only viable option to supply the larger stations in the medium term. Without developing a liquefaction capacity, there is a serious risk to H2-infrastructure development and implementation. However, at present liquefaction of H2 is expensive, energy intensive and relatively small scale. Reduction of liquefaction costs via technology development and increased competition is crucial. IDEALHY is an enabling project for viable, economic liquefaction capacity in Europe, to accelerate rational infrastructure investment, and enable the rapid spread of H2-refuelling stations across Europe. The IDEALHY project researches, develops and scales-up data and designs into an optimised design for a generic liquefaction process at a scale of 30-50 te/day, representing a very substantial upscale over proposed and existing LH2-plants. The project also develops a detailed strategic plan for a prospective large-scale demonstration of efficient H2-liquefaction with options for location. The focus is to improve substantially efficiency and reduce capital costs of liquefaction through innovations, including linking LH2 production with LNG terminal operations to make use of available cryogenic temperatures for pre-cooling. Supporting economic and lifecycle assessment of the resulting gains in energy efficiency will be made, together with a whole chain assessment based on near term market requirements. IDEALHY will be undertaken by a partnership comprising world leaders in H2 distribution and liquefaction technologies, research institutes, academic partners and pioneering SME suppliers to the liquefaction indus

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