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material to handle difficulties such as: machining,welding and corrosion had to be solved at the firststages of the prototype construction.To make sure a correct dissipater’s operation it isessential the liquid perfectly wet the aluminiuminternal wall. It can be achieved by a perfectaluminium wall cleaning [3] or surface treatment. Afteranalysing several techniques for improving the liquidwetting a nickel treatment (20 μm thickness film) waschosen. Then the stainless steel mesh (wickstructure) was placed at the evaporator zone andfinally the chamber sealed.Figure 2 shows the experimental results of the wickstructure capillary pumping.Stainless steelmeshCapillaryadvanceAluminiumFig.2 a): Experimental sep-up. Liquid’s front of advance.24-26 September 2008, Rome, ItalyFig.2 c): mesh detailThe results shown in figure 2 b) are thosecorresponding to a mesh with the characteristics ofthe fig. 2 c) and after having cleaned the aluminiumfilm. If no cleaning is done the liquid front stopsimmediately. It shows the so important a goodcleaning is for getting a good capillary pumping.Corrosion is also observed that affects negatively tothis pumping capacity and so the heat disposal.Two seal process were carried out: precision laserwelding with a Rofin equipment and cold welding withNeural 21 (Patted) compound. One of the mainchallenges when manufacturing the dissipater was toget the dissipater completely sealed. After no leakswere observed in the dissipater it was proceed to itsfilling up. With a thin catheter (1mm diameter, Vygon)the liquid is introduced (6, 8 y 10 ml distilled water)into the dissipater. Then the vacuum is made until theoperating pressure is reached.B- Measurement procedure and resultsTwo tests were carried out, one at 45ºC (-900 mb)and other at 60ºC (-800 mb). The inside pressure wascontrolled during the test by means of an externalmanometer connected to the dissipater’s chamber.The amount of heat to dissipate was generated by aflexible heater (Minco -Kapton and Rubber, of 25 mmx 25 mm area and variable input power) placed at theevaporator zone.Tests were done for 3, 5, 9 and 11 watts of heatdissipation from which temperature (thinthermocouples K type of Alhborn) at differentlocations in the dissipater, evaporator, adiabatic zoneand condenser, were recorded, figure 3.Fig.2 b): Advance velocity.©EDA Publishing/THERMINIC 2008 98ISBN: 978-2-35500-008-9