Abstract:
The invention concerns a fluid degassing device for degassing fluids, in particular resins. The device has a fluid supply element for supply of the fluid and a fluid discharge element for discharge of the fluid. Between the supply element and the discharge element there is at least one structural element for breaking down bubbles in the fluid as it flows through the structural element. In addition or alternatively there may be provided at least one profile element, over which the fluid must flow.

Description:
TECHNICAL FIELD 
       [0001]    The present invention concerns a device for and a method of degassing fluids. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Synthetic resins are used in the production of composite fiber components. In that respect it is important for the resin to be as free as possible of air inclusions or bubbles as such air inclusions have the effect on the material of weakening the structure. 
         [0003]    Thus degassing of the resin therefore has to be effected. Typically, the resin is introduced into stirring containers and stirred under vacuum. In that case, material degassing generally takes place only in the region near the surface. 
         [0004]    A further variant for resin degassing is represented by the so-called thin-layer degassing operation. As already stated hereinbefore degassing happens in particular at the surface while the high viscosity of the resin allows the gas bubbles to rise out of the depth to the surface slowly and therefore degassing is difficult. That necessitates long residence times. 
         [0005]    As an alternative thereto it is also possible to use semi-permeable films to permit resin degassing. 
         [0006]    As general state of the art attention is directed to WO 2003/064 144 A1 and U.S. Pat. No. 3,229,449 A. 
       BRIEF SUMMARY 
       [0007]    In one embodiment, there is provided a fluid degassing device for degassing fluids, such as resins. The device has a fluid supply element for supply of the fluid and a fluid discharge element for discharge of the fluid. Between the supply element and the discharge element there is at least one structural element for breaking down bubbles in the fluid as it flows through the structural element. In addition or alternatively there may be provided at least one profile element, over which the fluid must flow. The fluid degassing device further has a first chamber into which the fluid is fed by the fluid supply element. The first chamber has at least one first structural element in the form of a non-woven material. The device further has a second chamber which adjoins the first chamber. The second chamber has a second structural element which is in the form of a mesh and by way of which the fluid is passed. In a further aspect there is a separating wall between the first and second chambers. The separating wall has at least one gap. 
         [0008]    In a further aspect of the invention the device has a third chamber which adjoins the second chamber and which has at least one convex element. 
         [0009]    In a further aspect of the invention there is a separating wall between the first and second chambers and it has at least one gap. 
         [0010]    In a further aspect of the invention the device has a pivot axis for pivoting the device. 
         [0011]    In a further aspect of the invention the device has a mesh element which is arranged around the fluid discharge element. 
         [0012]    The invention also concerns a method of degassing fluids, such as resins. For that purpose a fluid is supplied, bubbles in the fluid are broken down by passing the fluid through at least one structural element and/or the fluid is passed over at least one profile element. The fluid can then be discharged. 
         [0013]    The invention also concerns a wind power installation rotor blade produced by a resin which has been degassed by the fluid degassing device. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]    The invention is described in greater detail hereinafter by embodiments by way of example and with reference to the drawings. 
           [0015]      FIG. 1  shows a diagrammatic sectional view of a resin degassing device, according to an embodiment of the invention, 
           [0016]      FIG. 2  shows a diagrammatic sectional view of a first end of a degassing device of  FIG. 1 , 
           [0017]      FIG. 3  shows a diagrammatic sectional view of a transition between a first and a second chamber of the degassing device of  FIG. 1 , 
           [0018]      FIG. 4  shows a diagrammatic sectional view of a further transition between the second chamber and the third chamber in the degassing device of  FIG. 1 , and 
           [0019]      FIG. 5  shows a diagrammatic sectional view of a detailed portion of an end of the third chamber of the degassing device of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  shows a diagrammatic sectional view of a resin degassing device according to a first embodiment. This device serves for degassing and in that respect can be provided with a pivot mounting  300 , by way of which the degassing device can be adjusted. The flow rate of the resin can be adjusted by the degree of inclination. In that case the inclination of the device can be set at between 1 and 10% and determines the resin layer thickness and the residence time in the vacuum and thus ultimately the degassing quality. 
         [0021]    The resin to be degassed is introduced into a first chamber  150  through a connection  12 . The resin then flows through a second chamber  160  into a third chamber  190  in order then to flow out by way of a flow discharge  310 . In the first chamber  150  the resin flows out of the supply connection  12  through a non-woven material  100  to the bottom of the first chamber  150  in order to flow through a first gap  200  or an opening in a first wall  210  between the first and second chambers  150 ,  160  into the second chamber  160 . A plurality of grills or meshes  180  are located in the second chamber. The resin must flow through the meshes  180  so that bubbles in the resin can be removed. The resin flows into the third chamber  190  through a second gap or opening  201  in a second wall  211  between the second and third chambers  160 ,  190 . Provided in the third chamber  190  are a plurality of profile members  220 , over which the resin flows. Thus the region of the resin, that is near the surface, is enlarged in size in the third chamber, which has a positive effect in degassing. Provided at the end of the third chamber  190  is a flow discharge  310 , by way of which the degassed resin can flow away again. 
         [0022]      FIG. 2  shows a diagrammatic sectional view of a first end (detail F) of the degassing device of  FIG. 1 . The resin is introduced into the container, that is to say into the first chamber  150 , through a supply connection  12 . Provided beneath the supply connection  12  is at least one layer of non-woven material  100 . In that case the non-woven material  100  should be of such a configuration that the resin can flow slowly therethrough. Thus, the first bubbles can already be removed from the resin by the structure of the non-woven material. The resin thus flows through the non-woven material  100  and through a first gap or opening  200  in the first wall  210  from the first chamber  150  into the second chamber  160 . 
         [0023]      FIG. 3  shows a detailed view of the detail E in  FIG. 1 , that is to say the transition between the first and second chambers  150 ,  160  in  FIG. 1 . Arranged in the second chamber  160  are a plurality of transverse struts  170  respectively disposed at the top and the bottom of the chamber  160 . Meshes  180  are stretched between the respective transverse struts  170  which have for example a mesh width of some millimeters. The resin flowing through the first opening  200  in the first wall  210  into the second chamber must overcome the first transverse strut  170  at the bottom of the chamber and thus flows over that transverse strut  170  so that, in flowing down from the transverse strut  170 , the resin must flow through the mesh  180 . In addition the transverse struts  170  can optionally have gaps  206  at the bottom of the second chamber  160 . Accordingly, the provision of the transverse struts  170  provides that the resin flows upwardly at the transverse struts  170  so that the surface area of the resin is increased in size, which results in improved degassing. In addition, when flowing down from the transverse struts  170 , the resin must flow through the meshes  180  which cause further degassing of the resin. 
         [0024]    In that case the first gap  200  can be relatively thin in order to achieve a relatively thin resin layer flowing therethrough so that the bubbles are moved into the region near the surface. The viscosity or flow rate can be adjusted by adjusting the temperature. The meshes  180  can also be of a multi-layer nature. The mesh structure in that case can be made of plastic fiber or metal, as long as it is ensured that the mesh is not dissolvingly attacked or dissolved by the resin. Thus the mesh structure represents a parameter in respect of resin degassing. In some embodiments, the transverse struts  170  may not terminate directly with the bottom of the left-hand chamber  160 , but rather there can also be gaps between the transverse struts and the bottom of the left-hand chamber  160  so that the through-put rate in resin degassing can be increased. 
         [0025]      FIG. 4  shows a detail D of  FIG. 1 , that is to say a transition between the second chamber  160  and a third chamber  190  which adjoins the second chamber at the left. The second separating wall  211  between the second chamber  160  and the third chamber  190  again has a second gap  201  at its lower side. Thus the resin is again forced to flow through that thin second gap  201 , whereby the surface area or the region near the surface is further increased in size. 
         [0026]    Profile members  220  are arranged in the third chamber  190  in such a way that the resin has to flow over the profile members so that this gives a further increase in the surface area or the region near the surface of the resin. Advantageously the profile members  220  are arranged upside down so that the resin can flow thereover. The profile members can be of a convex configuration. The third chamber  190  can be divided by a plurality of separating walls  212 - 215  each having a respective gap  202 - 205 . At least one profile member  220  is arranged in each of the divided chambers. The fact that the gaps  202 - 205  between the chambers or portions in the further chambers  190  are only very narrow means that only a small amount of resin flows through the gap  202 - 205  so that resin can accumulate in front of the gap, that is to say a resin accumulation  230  occurs. Because only a thin resin film flows over the edges of the profile members  220  the region near the surface is increased in size, which has a positive effect in terms of degassing. 
         [0027]      FIG. 5  shows a detail H in  FIG. 1 , that is to say a left-hand portion of the left-hand end of the third chamber  190 . Shown here is a flow discharge connection  310  which is not disposed down in the bottom but is placed upwardly in such a way that only the uppermost layer of the resin is skimmed off. In addition there can be still a further mesh  320  to remove further bubbles from the resin. 
         [0028]    Degassing of markedly more than 90% of the resin can be achieved with such a device. The entire device is operated under vacuum. The pressure in that respect is about 10 mbar. 
         [0029]    The resin which has been degassed by the above-described fluid degassing device can be used for the manufacture of a wind power installation rotor blade. Alternatively to that the resin which has been degassed by the fluid degassing device can also be used for the manufacture of other components of a wind power installation. 
         [0030]    The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent application, foreign patents, foreign patent application and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, application and publications to provide yet further embodiments. 
         [0031]    These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.