An elevator with millimeter precision – How to lift a 20-meter long pipe
Text: Heinz Maier-Leibnitz Zentrum, 18.03.2019 (amended)
There is a lot of excitement in the neutron guide hall of the Heinz Maier-Leibnitz Zentrum in Garching, where the Jülich Centre for Neutron Science (JCNS) operates most of its instruments for research with neutrons. One of these, the small angle scattering diffractometer KWS-2, which weighs about 5 tons, is about to be raised up and repositioned.
It is a Herculean task to move this colossal stainless steel pipe, not just because of its weight but rather due to the coordination needed to do this. By around 10 o’clock in the morning, about half of the task was done. “Everything is going as planned and we are probably going to finish the task today”, says Simon Staringer. He is an engineer at JCNS and, together with his colleagues Kendal Bingöl and Jos Daemen, engineer at the Central Institute of Engineering, Electronics and Analytics, Engineering and Technology (ZEA-1) at Forschungszentrum Jülich, is responsible for the repositioning of the pipe.
Twenty-five times higher performance
But let’s start from the beginning. One component of the instrument KWS-2 is a 22-meter-long pipe with a diameter of 1.4 meters. Inside, the detector can move within a range of one to 20 meters behind a probe to measure the small angle scattering of various materials. In 2015 it was equipped with a new detector, capable of performing measurements up to 25 times higher than its predecessor. The new detector is also equipped with a larger active area than the old one. The only problem was that the scientists were not able to use this increased efficiency optimally, because the neutron beam did not hit the new detector in the center.
As a result, at short distances from the probe, the detector was not able to measure neutrons striking its bottom edge. As the detector uses the whole of the cross-sectional area, an interior adjustment was not possible. So, how to solve this problem? The only option left was to move the whole pipe to the required position, i.e. ten centimeters above the current one.
Dr. Aurel Radulescu, the first instrument scientist, explains all this while the instrument behind him gradually moves upwards. He came together with his colleagues to watch the pipe’s journey. Actually, to call it a journey is not really accurate, as no movement is visible. One can however, hear the hydraulic lifts loud and clear. Dr. Radulescu is standing at a distance so as not to disturb the work of Simon Staringer, Kendal Bingöl and Jos Daemen.
Instead of lifting bridges or buildings, this time, a scientific instrument
For the lifting, they hired external professionals, deciding that the company A&K Hebetechnik from Berlin should do the job. Normally this company lifts bridges or buildings but they are capable of coping with this task as well. Sixteen hydraulic lifts are positioned under the pipe. With an elaborated valve control system and a computer-controlled displacement measurement system they are about to lift the experiment millimeter by millimeter. But why this much effort?
“The whole lifting process has to happen simultaneously otherwise the pipe could bend. This would lead to a misalignment of the rail system and to leakages in the system”, explains Kendal Bingöl. “Exactly”, adds Simon Staringer and turns his eyes nervously form the pipe to the lift control and back. “The instrument has to be evacuated during a measurement. A single hairline crack in a welded seam or a damaged seal would lead to a long down-time of the experiment.” No wonder there is so much tension in the air.
However, the technicians from A&K Hebetechnik do not seem to be affected by the pressure, and so the pipe reaches its destination safely.
The relief is even greater when the position of the pipe is measured at the end. The two ends are only two millimeters apart, which lies within the acceptable range. “We can correct those differences tomorrow by hand. We just have to adjust the bolts and get everything in place”, announces Simon Staringer. This was also the sign that it was time to dismantle the hydraulic jacks. After the group picture, the neutron guide hall slowly empties as everybody leaves.
“Seems like everything worked out in the end. But we can only be certain that the neutron beam is going to hit the detector in the right way when the neutron source is operative again”, says Simon Staringer whilst leaving the hall.
Fortunately, soon after opening the neutron beam for the next cycle it was clear that the repositioning of the pipe had been a success. The beam now strikes the detector in the middle and Dr. Aurel Radulescu and his colleagues can at last use the full potential of their detector.
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