This paper considers a class of high-speed airjet weaving machines that is characterized by excessive harness frame vibration, resulting in premature failure. This problem is tackled through addition of an auxiliary, input torque balancing mechanism: A centrifugal pendulum, of which the pendulum motion is imposed by an internal cam. While earlier work by the same authors focused on the design, optimization, and robustness analysis of this mechanism, the current paper presents experimental results. The considered setup is an industrial weaving machine à blanc equipped with a centrifugal pendulum prototype. Below a critical speed, the prototype functions as predicted and significantly improves the machine dynamics: The drive speed fluctuation is reduced by a factor of 2.5 and the vibration level of the harness frames is halved. Above the critical speed, however, torsional resonance dominates the machine dynamics. This phenomenon is verified on simulation by extending the rigid-body setup model, on which the centrifugal pendulum design is based, with a torsional degree of freedom.

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The ASME Section VIII Division 3 Pressure Vessel Design Code adopted in its 2004 edition a significant change of the design margin against plastic collapse. There are several reasons and justifications for this code change, in particular the comparison with design margins used for high pressure equipment in Europe. Also, the ASME Pressure Vessel Code books themselves are not always consistent with respect to design margin. This paper discusses not only the background material for the code change, but also gives some practical information on when pressure vessels could be designed to a thinner wall.

Research conducted in a high pressure polyethylene plant in Belgium, indicates that certain conventionally designed and scaled-up safety relief valves did not open consistently with ethylene at 300 barg and also at 250 barg. Comparative tests in the high capacity at the High Pressure Laboratory of a German safety relief valve manufacturer showed that the same conventionally designed and scaled-up safety relief valves tested at a set pressure of 250 barg had high lift fluctuations on air but did not open on water. It was also demonstrated that a safety relief valve designed by a German manufacturer, which opened reliably on air and on water at a set pressure of 250 barg also opened reliably on ethylene at a set pressure of 250 barg (i.e. supercritical condition). The comparative tests with ethylene in the polyethylene plant in Belgium showed also that the blow down values on that valve with ethylene are similar to the blow down values with water. Therefore it looks like the flow behavior in the safety relief valve with supercritical ethylene is similar as with a liquid. This plant testing on ethylene at 250 barg indicates that there are advantages to using the German manufacturer’s designed safety relief valves with the certified “one trim design” for liquid and gas.