Title of Invention	PROTECTIVE LEYER FOR FLUID FLOW MACHINE
Abstract	The invention relates to a protective layer for fluid flow machine comprising a protective coating which is applied to sections of the component and forms the water—guiding surfaces. At least one fiber layer which is embedded in the protective layer; and the material of the fiber layer is chosen from an aromatic polyamide or a plastic material of a similar or the same impact strenght.

Full Text

A turbo machine, especially a water turbine The invention relates to turbo machines such as water turbines, water pumps or pump turbines. It relates in particular to such components of such machines which have water-guiding surfaces. Primarily such regions of such components are concerned which during operation are flowed against by water. As is known, water flowing through such machine can comprise solids such as stones, wood or other flotsam. Depending on the location of the machine, even chunks of ice reach the turbine during the cold season. All these materials have a strongly abrasive effect. That is why the respective components, or at least their endangered regions, are coated with an abrasion-reducing material. A known protective layer consists of polyurethane (PU). Under normal conditions, i.e. rivers which carry a moderate to medium quantity of flotsam, the protective layer constitutes a very good protection of the thus coated metallic component against damage. Recently, however, cases have occurred more frequently in which the rivers carry high amounts of heavy parts such as rocks and earths and other flotsam which cannot be removed due to local conditions. The solid materials occur very frequently and have a high weight. Due to this and due to the high speed, such objects also hit the protective layer with a high amount of energy. High peaks of tension thus occur locally. As a result of the frequent and repeated impingement of objects, this leads to a flaking of the protective layer and finally to a damage to the underlying metallic surface. The surface of the protective layer becomes rough and uneven, and is also partly removed which leads to an impairment in the guidance of the flow and thus at least to a deterioration in the efficiency, if not to consequential damage to the turbine or other parts. It has already been considered to make the endangered regions of metallic components of turbines or the like of easily exchangeable layers of the extremely wear-proof materials and to exchange these layers from time to time. This has proved to be impracticable in the aforementioned extreme state of the rivers. DE 4226030 discloses a protective layer for turbine components es.blades consists of a fluid or semi-fluid material which is coated directly onto the component surface to give a deformable» wear-resistant layer (46). The layer (46) is based on a polyurethane polymer. A device for coating application is also claimed and comprises a tool (36) which corresponds to the inner face of a turbine blade (16). A molding gap (40) is formed between the blade (16) and tool (36) surfaces USE/ADVANTAGE - For resisting wear on turbine components, esp. the blades of a hydro- electric power plant (claimed). Reduces coating repair costs and maintenance time. Eliminates the need to return components to the manufacturer. US 5390430 discloses a thermoformable thermoplastic composite material has a core sufficiently thick to provide for a shaping of the composite mmaterial at an elevated temperature to any desired configuration. Layers of a fabric material disposed on opposite sides of the core may be formed of glass, carbon or aramid and from woven fibers, unidirectional or chopped fibers or random strand mats. The fabric layers are sufficiently thick to impart strength and rigidity to the composite material. Layers of a thermoplastic thermoformable resin material may be disposed on the fabric layers. The thermoplastic layers impregnate the fabric layers, bond the fabric layers to the core and provide a smooth external surface to the composite material. The core is preferably thinner than the combined thicknesses of the fabric layers and the thermoplastic layers. For example, the thickness of each fabric layer may be 0.008" -0.009", of each thermoplastic layer may be 0.0005" -0.0G2" and of the thermoplastic composite material may be 0.035" -0.060". A thermoplastic layer of an elastomer such as urethane is bonded to one of the thermoplastic layers with a thickness of approximately 0.010' -0.020" to impart abrasion resistance and high impact strength to the thermoplastic composite material. The composite material may illustratively be disposed externally in the sole of a shoe with the elastomer facing outwardly. OBJECT OF THE INVENTION The invention is based on the abject of providing measures with which the water guiding surfaces of metallic components of turbo machines, and in particular of water turbines, pump turbines or pumps, can be protected in such a way that the protection is maintained for a considerably longer period of time than was previously the case. DETAIL DESCRIPTION OF INVENTION The inventors have taken a new route. They have started out with the known and reliable PU coating. However, they have introduced layers of fibers into said coating, namely of an aromatic polyamide (so-called aramid) or of a plastic with the same impact strength. The said material is of ultimate relevance. Practice has shown that it is ideally suitable to avoid local peaks of tension by rerouting the impact energy perpendicularly to the impact direction and by diverting the same, so that local peaks of tension reach substantially lower values. The protective layer plus the fiber layer are thus maintained over a longer period of time. The time intervals between two repair processes are thus much longer than was previously the case. Accordingly, there is provided a component made of metal for a water turbine or any other fluid flow engine, comprising a protective coating which is applied to sections of the component and forms the water guiding surfaces characterized by the following features with at least one fiber layer which is embedded in the protective layer, and the material of the fiber layer is chosen from an aromatic polyamide or a plastic material of a similar or the same impact strength. The said fiber layers are approximately applied in a compound, i.e. as a woven or knitted fabric. A linen weave is considered, but also a twill weave or atlas weave. Twill and linen weaves have proven to be particularly advantageous in the laboratory. In the case of aramid fibers a fiber material of an especially high tensile strength should be chosen. Values of between 2500 to 3000 MPa are desirable, with 2900 MPa being the value. The tensile modulus of elasticity should lie between 100 and 150 GPa, best in the magnitude of 130. The fibers must be completely embedded in the PU material, so that they do not project beyond the water-guiding outside surface. When viewed in a cross section through the protective layer, several layers can also be disposed above one another, e.g. two or more layers of a fabric. Instead of a polyurethane coating it is also possible to consider other coating materials which are used for protection against erosion. WE CLAIM: 1. A component made of metal for a water turbine or any other fluid flow engines comprising a protective coating which is applied to sections of the component and forms the water guiding surfaces, characterized by the following features : with at least one fiber layer which is embedded in the protective layer, and the material of the fiber layer is chosen from an aromatic polyamide or a plastic material of a similar or the same impact strength. 2. A component as claimed in claim 1, wherein the fibers consist of a high modulus material. 3. A component as claimed in claim 2, wherein the tensile strength of the fibers is at least 2500 MPa, and the modulus of elasticity in tension is at least lOO BPa. 4. A component as claimed in one of the claims 1 to 3, wherein the fibers are present in the form of interlaid scrim or woven textiles or knitted fabrics. 5. A component as claimed in claim 4, wherein the fibers are present in the form of a tabby weave or twill weave or atlas weave. 6. A component as claimed in one of the claims 1 to 5, wherein several fiber layers arc provided, as seen in a cross section through the protective layer. 7. A component as claimed in one of the claims 1 to 6, wherein fibers do not project beyond the water-contacting surfaces of the protective layer. 8. A component as claimed in claim 7, wherein the water- contacting surfaces are formed exclusively by the material of the protective layer. 9. A component as claimed in one of the claims 1 to 8, wherein the protective layer consists of polyurethane. The invention relates to a protective layer for fluid flow machine comprising a protective coating which is applied to sections of the component and forms the water—guiding surfaces. At least one fiber layer which is embedded in the protective layer; and the material of the fiber layer is chosen from an aromatic polyamide or a plastic material of a similar or the same impact strenght.

Documents:

234-kol-2003-granted-abstract.pdf

234-kol-2003-granted-claims.pdf

234-kol-2003-granted-correspondence.pdf

234-kol-2003-granted-description (complete).pdf

234-kol-2003-granted-examination report.pdf

234-kol-2003-granted-form 1.pdf

234-kol-2003-granted-form 18.pdf

234-kol-2003-granted-form 2.pdf

234-kol-2003-granted-form 26.pdf

234-kol-2003-granted-form 3.pdf

234-kol-2003-granted-form 5.pdf

234-kol-2003-granted-priority document.pdf

234-kol-2003-granted-reply to examination report.pdf

234-kol-2003-granted-specification.pdf

234-kol-2003-granted-translated copy of priority document.pdf