Patent Application
20120080366
This application claims priority of German Patent Application No. 10 2010 041 750.5 filed Sep. 30, 2010, which is incorporated by reference herein in its entirety.
The present invention relates to a device for filtering lubricants of a wind turbine transmission, a wind turbine comprising such a device, and a method for filtering lubricants of a wind turbine transmission.
Wind turbine transmissions are exposed to adverse effects of water. The water can attack both the transmission and the lubricants.
Water occurs in the transmission in the form of so-called “free water”, in absorbed form or as part of an emulsion. When separating water by means of electrolysis, hydrogen is released. This can result in crack propagation and fractures in the material. In addition, both free and absorbed water result in increased aggressive acid potential and hence in corrosion and pitting on the surfaces. The removal of iron oxides can likewise result in the formation of fractures.
Furthermore, water has a negative effect on the properties of the transmission lubricants. For example, transmission oil can oxidize in the presence of oxygen due to the raised temperatures. If water and metal particles, e.g. wear debris, are present in the lubricating oil, antioxidants are expended more rapidly and this again results in corrosion on the metal surfaces. Further possible consequences include the formation of sludge and film, and uneven oil flow.
Water also reduces the efficiency of other additives, thereby promoting the formation of acid and sludge on the floor of the oil sump. Other possible consequences include technical problems such as the formation of foam or microbial impurities in the oil, and a reduction in the stability of the oil film or a change in the viscosity of the oil.
The service life of the transmission of a wind turbine therefore depends heavily on the relative water content in the transmission oil.
As a result of this, filter systems for filtering the transmission oil are used in wind turbines, removing particles, dirt films and water from the oil. These known filter systems make use of extremely absorbent filter materials. As the oil flows through, particles are trapped in the filter material and water content is bonded.
The disadvantage here is that the pores of the filter material become clogged over time. It is therefore necessary regularly to replace the filter material with new filter material, in order that the functional efficiency of the filter system can be guaranteed.
The changing of the filter material is demanding and expensive in this case, particularly in the case of wind power installations at sea, which are difficult to access.
An object of the claimed invention is to provide an improved device for filtering lubricants of a wind turbine transmission, in which the clogging of the filter material due to water content is reduced in comparison with known filter devices of this type.
The object is solved by the device as claimed in the independent claim. Advantageous developments of the invention are defined in the dependent claims.
The inventive device for filtering lubricants of a wind turbine transmission comprises a lubricant inlet and a lubricant outlet. Lubricants of the wind turbine transmission are carried from the lubricant inlet to the lubricant outlet.
In addition, the device has a filter element which is arranged between the lubricant inlet and the lubricant outlet. The filter element is designed in such a way that water is separated from the lubricants by the filter element.
A water outlet is connected to the filter element in such a way that the separated water can be drained out of the device.
A hydrocarbon adsorber is arranged between the filter element and the water outlet in such a way that it removes hydrocarbons from the water that has been separated out.
The filter element that is used for separating water from the lubricant releases the separated water. Provision is further made for filtering out any lubricant content that is included in the water, such that the water can be allowed to escape automatically.
This allows longer filter change intervals. In addition, the maintenance costs for the hydrocarbon adsorber are low because the adsorber can be regenerated and the adsorber material itself is inexpensive.
An embodiment of the invention comprises at least one measuring entity for detecting the hydrocarbon content in the water, and at least one controllable outlet valve. It is thereby ensured that only purified water is allowed to escape from the device.
Exemplary embodiments of the invention are described with reference to the appended drawings, in which:
As shown in
The transmission oil is preferably carried though the filter device under pressure from a pump, but alternatively can flow through the device without pressure and solely due to gravity by virtue of the relative arrangement of oil inlet (1) and oil outlet (2).
A filter element (3) is arranged between the oil inlet (1) and the oil outlet (2). The filter element (3) is designed to separate water from transmission oil or other lubricants. For this purpose, the filter element (3) features a hydrophobic fibrous braided fabric and/or a hydrophobic mesh-type material.
The filter element (3) is designed in the shape of a cylinder and is so arranged in the filter housing that its circumferential surface is surrounded by the lubricant.
In the embodiment of the invention shown in
The filter element (3) is connected to a water outlet (4), specifically on its side which faces away from the oil. Water that is separated from the oil is drained out of the device via the water outlet (4).
The water that is separated from the transmission oil is therefore not bonded by the filter material, as in known filter devices for wind turbine transmissions, but is released. As a result of this, the filter element (3) has a longer service life.
The water that is separated from the transmission oil usually includes small quantities of transmission oil, and is therefore purified in the device according to the invention. In addition, a hydrocarbon adsorber (6) is provided between the filter element (3) and the water outlet (4).
The hydrocarbon adsorber (6) is arranged in such a way that the separated water passes through the adsorber on its way to the water outlet (4). The hydrocarbon adsorber (6) itself features a hydrophobic adsorbent, preferably active carbon.
Active carbon, also referred to as activated carbon, has a very large surface relative to its weight. By virtue of its highly porous structure, it is capable of separating impurities from liquid or gaseous materials.
When the water flows through the active carbon, hydrocarbon content is adsorbed by the inner surface of the filter. The water is not chemically bonded and is released again. It can be collected and drained out.
Alternatively, carbon molecular sieves can be used as an adsorber material.
By means of energy input such as temperature or pressure changes, for example, a saturated hydrocarbon adsorber (6) is liberated of the adhered hydrocarbons, i.e. regenerated, and can be re-used.
In the embodiment shown in
In a further embodiment, the hydrocarbon adsorber (6) is arranged below the filter element (3) as shown in
The embodiment of the invention as shown in
In addition, a temperature sensor (8) can be provided for measuring the temperature of the separated water.
In this embodiment, due to its shape, the filter element (3) has a chamber in its interior. The chamber is coupled to the water outlet (4), such that separated water can be drained out of the chamber. In this case, one or more measuring entities (7a, 7b, 8) are arranged in the chamber or downstream in the direction of the water flow and below the chamber or below the hydrocarbon adsorber (6). The separated water drips into the chamber or is sucked into the chamber and out of the chamber.
The water outlet (4) comprises at least one outlet valve (10a, 10b), which is preferably designed as a magnetic valve. An escape channel is arranged between the filter element (3) and the at least one outlet valve (10a, 10b), and comprises a water collecting region (5) for separated water.
Two outlet valves (10a, 10b), which can be opened and/or closed independently of each other, can be arranged between filter element (3) and water outlet (4) as mentioned above. Such a variant of the invention is illustrated in
In this case, the two outlet valves (10a, 10b) are operated in such a way that the measuring result of a first sensor (7a) is analyzed initially. If the hydrocarbon content is below a limit value, the first outlet valve (10a) in the flow direction of the water is opened. The measuring result of a second hydrocarbon sensor is then analyzed. Only if this result likewise does not exceed a predefined limit, is the second outlet valve (10b) in the flow direction of the water opened and the water passes through the water outlet (4).
As shown in
Furthermore, the control entity (9) has a data interface or man-machine interface for local monitoring and/or remote maintenance of the device. It is therefore possible to display corresponding maintenance information or transmit a corresponding signal to a central facility.
The device consists of three segments (K, M, B). The lubricant inlet (1) is arranged in a top segment (K). A middle segment (M) comprises a lubricant container and the filter element (3) that is arranged therein. The control entity (9), at least one measuring entity (7a, 7b, 8) and the water outlet (4) are arranged in a base segment (B). The proximity of control unit (9) and measuring entity or measuring entities (7a, 7b, 8) is advantageous in this case.
Relative to a vertical axis, the top segment is arranged uppermost, the middle segment in the middle, and the base segment at the bottom.
In another embodiment of the invention, the top segment comprises an additional filter element, which filters particles out of the lubricant. The additional filter element is embodied and arranged in such a way that it can be exchanged with ease.
Alternatively, such a filter element for separating particles can also be connected as a separate filter ahead of the device according to the invention. In the same way, a filter element for particle separation can be arranged as a further filter layer externally around the filter element (3) for water separation. In the last cited variant, the filter element for particle separation is likewise connected ahead of the filter element (3) for water separation.
In a further embodiment of the invention, the device according to the invention is part of a wind turbine transmission, wherein the oil outlet (2) of the device is connected to the transmission.
The invention further comprises a method for filtering lubricants of a wind turbine transmission, in which water is separated from lubricants of the wind turbine transmission by means of a filter element (3), and in which the separated water is purified of hydrocarbons by means of a hydrocarbon adsorber (6).
The draining of the purified water from the device preferably takes place depending on the hydrocarbon content and/or the temperature of the separated water.
Any of the features presented in the above description and in the following claims can be essential to the invention, either alone or combined together in any way.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102010041750.5 | Sep 2010 | DE | national |
