• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method for automatically retrieving bolt length information of a plurality of bolts securing two parts of a wind turbine, wherein the plurality of bolts are having a bolt head including a top surface and a threaded part including a bottom surface and wherein an ultrasonic transducer comprises a power supply, a transducer element and a communication interface, the method comprising the steps of: attaching one ultrasonic transducer to either the top surface or the bottom surface of each of the plurality of bolts by means of a coupling agent, performing a plurality of bolt length measurement including retrieving bolt length information by means of the ultrasonic transducer wherein each of the plurality of bolt length measurements are separated in time, and transmitting the bolt length information from the ultrasonic transducer to a control device.
    公开号:DK201570840A1
    申请号:DKP201570840
    申请日:2015-12-21
    公开日:2017-07-10
    发明作者:Jørgen Dahl Vestergaard；Jacob Skipper Jørvang
    申请人:Kk Wind Solutions As；
    IPC主号:
    专利说明:

    Ultrasonic bolt monitoring
    Field of the invention
    The invention relates to a method and an apparatus for determining the length of a bolt, tightening together two wind turbine components, by means of an ultrasonic transducer. By regularly measuring such a bolt length it is possible to evaluate if the bolt continues to be correctly tightened.
    Background of the invention A wind turbine is built from a plurality of different components some of which are secured by means of bolts. These bolts have to be correctly tightened during the lifetime of the wind turbine to ensure safe operation of the wind turbine.
    Different solutions for automation of this tightening of bolts have been disclosed such as different robotic arms as the once disclosed in KR101259042 and KR101368670.
    Other prior art discloses tools for monitoring the level of tightness of bolts fastening parts of a wind turbine.
    Other prior art discloses measuring the length of the bolt by means of ultrasonic technology. As an example hereof is US5I31276 which discloses to growing an ultrasonic measuring device on top of the bolt head by means of vapour deposition.
    Brief description of the invention
    It is an objective of the present invention to provide an alternative method for monitoring a plurality of bolts in a wind turbine, and especially it is an objective to provide an automatic method tor monitoring a plurality of bolts in a wind turbine, simultaneously and/or sequentially, while the wind turbine is in operation, which can also be applied after commissioning the wind turbine, as a retrofit system.
    The invention relates to a method for automatically retrieving bolt length information of a plurality of bolts securing two parts of a wind turbine, wherein the plurality of bolts are having a bolt head including a top surface and a threaded part including a bottom surface and wherein an ultrasonic transducer comprises a pow'er supply, a transducer element and a communication interface, the method comprising the steps of: - attaching one ultrasonic transducer to either the top surface or the bottom surface of each of the plurality of bolts by means of a coupling agent, - performing a plurality of bolt length measurement including retrieving bolt length information by means of the ultrasonic transducer wherein each of the plurality of bolt length measurements are separated in time, and - transmitting the bolt length information from the ultrasonic transdu cer to a control device. The securing of wind turbine parts should be understood as connecting or fastening two parts such as a blade to the hub or two tower sections to each other.
    The present invention is advantageous in that when the ultrasonic transducers are mounted and transmitting bolt length information to a control device, then manually inspection of the securing of the wind turbine parts is avoided. From the bolt length information it is possible to derive information related to bow good two wind turbine components are fastened to each other.
    Further the present invention is advantageous in that it facilitated monitoring a plurality of bolts simultaneously when the wind turbine is in operation
    Further the present invention is advantageous in that it facilitated installing the means required for carrying out the method after the wind turbine is commissioned i.e. the present invention is suitable for retrofitting to any type of wind turbine.
    The separation in time between bolt length measurements is preferably determined by weighing parameters such as transducer power supply capacity, power consumption per measurement, lifetime of the power supply, need or use of measurements etc. In most situations one measurement once per hour will be high frequency whereas one measurement per day would be consider medium frequency and more time between measurements would be considered low frequency. As can be imagined the separation time can vary from one period to another.
    In the ideal situation an ultrasonic transducer is secured to all blots securing the wind turbine parts. However if some bolts are not equipped with an ultrasonic transducer or equipped with an ultrasonic transducer which fails, this will not prohibit the present invention from being advantageous compared to the manual or automatic inspection method known today. With this said the number of bolts included in the plurality of bolts should be considered carefully. Hence the frequency of bolts with ultrasonic transducer should be sufficient to be able to detect loosened bolts before these become crit ical to the securing of the two wind turbine parts.
    Depending on the bolt to be measured, location of the ultrasonic transducer at either the top or bottom surface (also referred to simply as bolt surface) is possible. Hence depending on the type of coupling agent, size of bolt, location of bolt the easiest surface of mounting should be chosen.
    The bolt length information retrieved by the ultrasonic transducer is preferably a time delay measured from when an ultrasonic signal is sent from the ultrasonic transducer until its echo is returned from when this signal reaches the opposite end of the bolt and registered again by the ultrasonic transducer. Alternatively it is length or other information derived from the ultrasonic measurements from which length of the bolt can be determined. A control device advantageously receives the bolt length information and if present also information identifying the bolt from which the information is received. Thereby it becomes possible to analyses the bolt length information from the individual bolts.
    Wireless communication between the ultrasonic transducer and the control device is advantageous in that wired connections of e.g. more than 50 ultrasonic transducers per blade in a wind turbine blade / hub attachment would introduce a huge source of error, higher system cost and risk of faulty mounting.
    The power supply preferably comprises an energy harvesting device in combination with one or more capacitors.
    Accordingly, by the present invention a method of obtaining individual bolt length information for use in determining if a bolt is loosed is presented thereby avoiding or at least supplementing manual inspection. The present invention is especially advantageous in that it can easily be retrofitted to existing wind turbines where need for bolt monitoring has turned out to be necessary.
    According to an embodiment of the invention, the coupling agent comprises an adhesive component. A coupling agent comprising an adhesive component is advantageous in that bidirectional signals between the ultrasonic transducer and the bolt head can be transmitted through the coupling agent which at the same time facilitates securing of the ultrasonic transducer to the bolt head. it should be mentioned that in situations where the coupling agent does not facilitate the securing the ultrasonic transducer to the bolt surface, the coupling agent could be an elastomeric material such as rubber or other suitable flexible materials.
    According to an embodiment of the invention, the coupling agent comprises at least one component of the list comprising: epoxy, silicone grease and oil. A coupling agent comprising adhesive components such as epoxy. Alternatives hereto could be silicone grease, rubber membrane, or the like, these are advantageous in that it facilitates a sufficiently securing of the ultrasonic transducer to the bolt head required for the environment in a wind turbine. At the same time as it allows the ultrasonic waves from the ultrasonic transducer to pass through and thereby ensure sufficient quality of the bolt length information signal.
    According to an embodiment of the invention, an ultrasonic transducer is attached to at least 50% of the bolts securing the two wind turbine parts, preferably to at least 75% and most preferably to at least 90%. In embodiments of the invention 100% of the bolts are provided with an ultrasonic transducer. The larger percentage the more reliable the overall monitoring of the securing of the wind turbine parts would be. Further the more bolts having an attached ultrasonic transducer the more the automatic method of monitoring the bolts is like the present manual method. In addition, as an example two components might be held in place with only 75% of the available bolts however in case of load is applied to the two components 75% of the available bolts may not be enough to keep the components fastened. This could in worst case lead to separation with possible material or human damage, therefore it is preferred to have ultrasonic transducers on each bolt or at least above 90% of the bolts.
    According to an embodiment of the invention, the transducer element is of a type of the list comprising: pitch-catch type, pulse-echo type, through-transmission and phased array type. The latter is advantageous in that beside the bolt length information it also provides information of cracks and corrosion for the bolts which are very relevant information. An advantage in relation to implementation of the pulse-echo type of ultrasonic application is that only one transducer has to be attached to one surface of the bolts.
    According to an embodiment of the invention, the control device comprises a data processor facilitating analyzing the received bolt length information to determine if any of the plurality of bolts are loosened. This information is obtained as the result of data processing in the control device or in the transducer. Hence the control device and / or the ultrasonic transducer preferably comprises one or more data processors, data storages and data communication interfaces. Hence from a comparison of the reference measurement and the continuously received bolt length information (or comparison among the retrieved measurements) information of loosened bolt can be obtained.
    According to an embodiment of the invention, the data processor further facilitates analyzing the received bolt length information to determine load distribution of the bolts. This is advantageous in that a load profile of the wind turbine may then be established on the basis of the bolt length information.
    According to an embodiment of the invention, tightening of bolts of the wind turbine is scheduled based on the result of the data processing in the control device of the received data. This is advantageous in that tightening of bolts can be planned together with other maintenance tasks which would also require production stop of the wind turbine.
    According to an embodiment of the invention, the control device is located in the wind turbine and facilitates communication with an external data processor. This is advantageous in that information regarding the bolt length can be accessed from external to the wind turbine e.g. at a service provider in charge of sendee including fastening of bolts. Such external data processor may be a server located external to the tvind turbine. The communication to such external data processor may be made directly from the control device e.g. via the wind turbine controller.
    Preferably each ultrasonic transducer is communicatively coupled to the control device. The control device is then preferably communicatively coupled to the wind turbine controller. In this way it is possible to perform data analysis and data collection either in the control device or at the wind turbine controller. It is possible to perform data processing at the individual ultrasonic transducer however this is only preferred in situations where the power supply of the ultrasonic device is capable of meeting demands to such processing and communication of data.
    According to an embodiment of the invention, the bolt length information is retrieved while the wind turbine is in a production mode. This is advantageous in that monitoring of the securing of the wind turbine parts can be made without loss of production occurs. Further from the bolt length information, information of the load of parts of the wind turbine may be derived. Further, if the ultrasonic transducer is powered from energy harvesting, this is easiest done when the wind turbine is in operation.
    According to an embodiment of the invention, the ultrasonic transducer is equipped with an electronic identification tag or a visible identification tag. A visible identification tag is advantageous in situations where a service person is to tighten one or more bolts the information of which is retrieved from an electronic identification tag. A visible identification tag could be printed, casted, molded, labeled, etc. to the ultrasonic transducer or on the part it is tightening, it could be a number, QR code, letter, symbol or any combination hereof 12. Method according to any of the proceeding claims, wherein the ultrasonic transducer 7 is equipped with a data storage and / or a temperature sensor and / or a data processor. A data storage is advantageous especially for storing the echo signal and thereby the time delay between the emitted ultrasonic signal and the echo signal in that then a communication from a plurality of ultrasonic transducers can be scheduled independent on time of measurement.
    In case the ultrasonic transducer comprises a data storage, transmittal of data can be done e.g. by request from the control device or stored in case there is no communication to a control device. In situation with no data storage, the length information is preferably transmitted with undue delay after the retrieval of the information also referred to as real-time. A temperature sensor is advantageous e.g. if the bolt is exposed to high temperature during the day and low temperature during night. If such temperature differences are large it might have influence on the length, or measured/perceived length, of the bolt and therefore would be advantageous to be able to compensate for.
    Further, when using batteries as power supply ambient or bolt temperature is relevant in the determination of e.g. remaining lifetime of the battery, in addition in relation to warranty questions knowledge of temperature is important for documentation of correct environment of the battery. A data processor facilitating processing of bolt length information retrieved from the transducer element. This is advantageous in that then communication from the ultrasonic transducer is directly usable without further processing or analysis. Further, in case communication is not established between ultrasonic measuring device and control device storage of such data is facilitated.
    According to an embodiment of the invention, a guide is used to ensure that the ultrasonic transducer is secured to the top surface or bottom surface in such a way that the emitted ultrasonic signal from the transducer element is substantially parallel to the longitudinal direction of threaded part of the bolt. A guiding fixture is advantageous in that especially when ultrasonic transducers have to be secured to maybe 50 or over 100 bolts. Firstly it is assured that all ultrasonic transducers are secured in the same way and secondly it is ensured that the position of the ultrasonic transducer does not change during curing process of the coupling agent. The l atter is only relevant when the coupling agent cures and thereby fastening the ultrasonic transducer to the bolt. Thereby is obtained a correct positioning of the ultrasonic device both during mounting and use i.e. operation of the wind turbine.
    In addition, the guide is advantageous in that it is easy to tighten the guide firmly resulting in the layer of the coupling agent is as small as possible thereby ensuring air tight connection between holt and ultrasonic transducer. Further, the ultrasonic transducer is as close the to bolt as possible thereby limiting the possible sources of errors in the measurements
    According to an embodiment of the invention, the guide comprises a thread facilitating mounting the ultrasonic transducer to the bottom surface by mounting the guide by screwing it to the thread part of the bolt. Hereby is obtained an extremely user fri endly and fast mounting of the ultrasonic transducer.
    Moreover the invention relates to the use of an ultrasonic transducer for retrieving bolt length information of a bolt in a wind turbine according the method of any of the claims 1-14.
    Moreover the invention relates to a guide comprising a guide thread part facilitating mounting of the guide to a threaded part of a bolt and an ultrasonic transducer facilitating monitoring the length of the bolt to which the guide is attached. Such guide is advantageous in that it facilitates fast and easy mounting by standard tools such as a wench or the like. Further by using a torque wrench it is easy to mount even 100 guides exactly in the same way thereby reducing or completely eliminating this error .source when measurements are compared at a later stage.
    According to an embodiment of the invent ion, the guide further comprises a coupling agent facilitating an air free interface between the ultrasonic transducer and a bottom surface of the bolt. It is advantageous to add a coupling agent to the guide in such a way that when the guide is tightened to the bolt, an air free interface is made between the bottom surface of the bolt and the part of the guide comprising the ultrasonic transducer. The coupling agent may be applied just before mounting of the guide to the bolt of e.g. when the guide is manufactured. The latter however requires sealing of the guide to protect the coupling agent.
    According to an embodiment of the invention, a guide according to claim 16 or 17, wherein bolt length information is retrieved according to the method of any of the claims 1-14.
    Moreover the invention relates to the use of a guide comprising an ultrasonic transducer for retrieving bolt length information of a bolt in a wind turbine according any of the claims 16-17.
    According to an embodiment of the invention, the method further comprising an initial step of performing a reference measurement of bolt length information, preferably made by the ultrasonic transducer. The reference measurement is advantageous in that it enables analyzing the bolts to see if something is wrong with a bolt which would require replacement or tightening of the bolt and secondly reference information is obtained. The reference information is used for comparison with the result of the ongoing automatic measurements retrieved when the ultrasonic transducer is installed at the bolt. Preferably a reference measurement is made for all of the bolts to which an ultrasonic transducer is attached.
    Alternatively the ultrasonic reference measurement can be made with a handheld ultrasonic transducer which can be used for ultrasonic reference measurements of all of the plurality of bolts. Hence according to this embodiment of the invention the transducer for performing the ultrasonic reference measurements may be different from the ultrasonic transducer attached to the bolt performing the automatic measurements.
    The reference measurement is preferably stored by the control device or in the ultrasonic transducer as a reference measurement and preferably during a year with varying environmental impact a plurality of reference measurements is made.
    Thereby it is possible to account for primly temperature difference which may influence the length of the bolt and thereby if not accounted for disturb the analysis of the retrieved bolt length information.
    According to an embodiment of the invention, the reference measurement is made with a temporary ultrasonic transducer coupled to the top surface or the bottom surface with a coupling agent. The reference measurement is preferably made with at water based adhesive which is easy to remove from the bolt surface again after the reference measurement is made.
    No matter how the reference measurement is made the result hereof is preferably communicated to the control device. This is advantageous in that when the control device both receives reference measurements and the automatic / continuously retrieved measurements a comparison is easy to perform by the control device and thereby it is easy to determine if a bolt is looser compared to either earlier measurements or compared to the reference measurement.
    According to an embodiment of the invention, the coupling agent ensures air free interface between the ultrasonic transducer and the top surface or bottom surface. An air tight securing of the ultrasonic transducer to the bolt surface (top or bottom) is advantageous in that the quality of retrieved bolt length information increased since there is no air between the ultrasonic transducer to the bolt head to disturb the signal.
    According to an embodiment of the invention, the coupling agent facilitates a distance of less than 2 millimeter, preferably less than 1 millimeter, most preferably less than 0,5 millimeter between the ultrasonic transducer and the top surface or bottom surface. This is advantageous in that irregularities of the top surface of the bolt head or bottom surface of the threaded part is then compensated for by the coupl ing agent and thereby even if the bolt surface is not plane it is possible to secure the ultrasonic transducer so that the center of the line of the ultrasonic waves transmitted is parallel with the longitudinal direction of the threaded part of the bolt.
    Using coupling agent also has the advantages that preparation of the bolt surface is avoided. Preparation may include planishing the bolt surface for any protruding or caving in parts, making sure the surface towards the ultrasonic transducer is as clean and plan as possible. This is advantageous to obtain the highest quality of the bolt length information and best possible securing of the ultrasonic transducer to the bolt surface.
    According to an embodiment of the invention, at least part of the plurality of the bolts to which an ultrasonic transducer is attached are located between two neighboring bolts which does not have an ultrasonic transducer attached.
    According to an embodiment of the invention, at least part, of the plurality of the bolts to which an ultrasonic transducer is attached are having one neighboring bolt to which an ultrasonic transducer is attached and another neighboring bolt which does not have an ultrasonic transducer attached. It is advantageous to distribute the bolts to which an u ltrasonic transducer is attached equally along the line of bolts securing the wind turbine components. Especially in the situation where not all bolts are having an ultrasonic transducer attached.
    According to an embodiment of the invention, at least part of the plurality of the bolts to which an ultrasonic transducer is attached are having two neighboring bolts to winch an ultrasonic transducer is secured.
    Figures A few exemplar}' embodiments of the invention will be described in more detail in the following with reference to the figures, of which figure 1 illustrates a bolt the length of which is retrieved according to an embodiment of the invention, figure 2 illustrates an ultrasonic transducer coupled to a bolt according to an embodiment of the invention, figure 3a-3c illustrates various w ays of coupling an ultrasonic transducer to a bolt and figure 4 illustrates a guide for attaching the ultrasonic transducer to the bolt. Detailed description of the invention
    Figure 1 illustrates an example of a bolt 1 of which it is possible to retrieve the length by means of an ultrasonic transducer 7 as described in this document. The bolt i comprises a bolt head 2 having a top surface 3. The bolt 1 further comprises a threaded part 4 having a bottom surface 5.
    The bolt 1 illustrated in figure 1 is an example of the type of bolt wdiich is typically used for securing parts such as tower sections and blade to hub of a wind turbine. It should be understood that the ultrasonic transducer 7 could be used to retrieve the bolt length of any kind of bolt. It is preferred that the bolt diameter should not be smaller than the diameter of the ultrasonic transducer 7 or at least than the transducer element 9.
    Typically the bolt l uses a nut (not illustrated) in the securing of the wind turbine parts, or in some situations the second wind turbine part comprises a threaded part, with which the threaded part 4 of the bolt 1 interacts to secure the wind turbine parts. This is however known to the skilled person and not of particular relevance to the present invention, in that is works perfectly well no matter how the wind turbine parts are secured by means of bolts, and will therefore not be specified further.
    Figure 2 illustrates a bolt 1 of the type illustrated in figure 1 having a bolt head 2 to which an ultrasonic transducer 7 is attached with a coupling agent 6 between the top surface 3 and the ultrasonic transducer 7.
    The ultrasonic transducer 7 at least comprises a power supply 8, a transducer element 9 and a communication interface 10. It should be noted that additional components such as e.g. data processor, data storage, wires, batter}' charging device, etc. may also be part of or attached to the ultrasonic transducer 7. Situations or environments could provide the need for gathering some or all of these, and other not mentioned elements relevant for the ultrasonic transducer 7 to work in a specific situation or environment, in an external unit. A plurality of ultrasonic transducers 7 could in this situation be comiected to such an external unit.
    Typically the most energy' consuming component of the ultrasonic transducer 7 is the wireless communication, though other parts of the device can in themselves or in combination wdth each other have higher peak or average power consumption. Accordingly, depending on the choice of power supply' 8 including capacity hereof, a data storage could be advantageous to ensure that data can be transmitted when pow'er is available for the data transmission. Further, a data storage also facilitates scheduling of when many, e.g. 1000, ultrasonic transducers 7 are communicating with e.g. the control device 13.
    In some situations i s migh t be advantageous to include a data processor as part of the ultrasonic transducer 7. Depending on energy consumption of various scenarios in relation to energy consumption it might be preferred to process data at the ultrasonic transducer 7 and thereby only sending e.g. “1” for OK and “0” indicating the bolt length is shorter than expected. Alternatively it might be advantageous to send raw data and perform data processing e.g. at the control device 13.
    The power supply 8 is preferably implemented as one or more batteries, capacitors, piezoelectric devices, electrostatic devices and / or electromagnetic devices.
    The latter devices may also serve as indirect power supply by facilitate charging the batteries and / or the capacitors. According to embodiments of the invention energy harvesting systems are not limited to the above mentioned devices but could also be based on photovoltaic, thermal, radio frequency and/or inductive sources, as well as any new energy harvesting and / or energy storage solutions that should become available. Hence a variety of combination for generating power either to charge the battery or to power the transducer element 9 and if necessary the communication interface directly exists within the scope of the present invention.
    In an embodiment of the invention where power to the ultrasonic transducer 7 is facilitated by means of energy harvesting as described above, measurements may be made wiien power is available, and hence not scheduled as such as time between measurements, though scheduling is preferred.
    The transducer element 9 is the element transmitting and receiving emitted ultrasonic signal 11 and the echo signal 12 based on which the length of the bolt can be retrieved. It should be mentioned that, although not preferred, the transducer element 9 can be implemented as a transmitter element and a receiver element, i.e. not necessarily as one embedded device / element. A connection of two wind turbine components is designed to be tightened with a specific torque. When the two wind turbine components are tightened by means of bolts, the initial or reference bolt length is dependent on the torque with which the bolt is tightened and vice versa.
    Hence for the specific bolt a relationship exists between the torque with which it is tightened and the length of the bolt. In later bolt length measurements, if the length is shorter than the so-called reference length, the bolt is tightening the two components with less torque compared to the torque used when the reference length was measured. The bolt could then be said to be less tightly fastened than previously.
    Other influences in both actual bolt length and perceived bolt length exist e.g. variations in temperature, which affect both the bolt's actual length though thermal expansion/contraction, as well as the speed of sound through the bolt material, thus affecting the bolt length perceived by the ultrasonic device. Such influences can be compensated for e.g. with one or more temperature sensors and / or a temperature compensation algorithm. Valuable information for better compensating for such other influences may be obtained by performing a reference measurement prior to use of the ultrasonic transducer 7 in operation e.g. in the wind turbine.
    The principles behind ultrasonic measurement are based on measuring a time delay from when an emitted ultrasonic signal 11 is transmitted to when the echo signal 12 hereof is received (pulse-echo method), or alternatively from when the emitted ultrasonic signal 11 is transmitted to when it arrives at the bolt end 5, though this method (pitch-catch method) required ultrasonic transducers to be mounted on both ends of the bolt 7,9. The transducer element(s) 7,9 may be implemented using (but are not limited to) one of the following types/methods: pitch-catch, pulse-echo or phase array. Since ultrasonic measuring principles including the mentioned types or methods are w ell known they will not be described further.
    The coupling agent 6 serves at least twro purposes, the first of wrhich is, at least partially, securing the ultrasonic transducer 7 to the top surface 3, and the second, and most important, is to facilitate an air free interface eliminating air pockets between the ultrasonic transducer 7 and the top surface 3.
    The latter is preferred in that air between an ultrasonic transducer and the medium (here the bolt) to be measured are not appreciated in that air have a tendency to disturb the emitted ultrasonic and echo signals 11, 12 thereby reducing the quality of the information of the length of the bolt 1.
    The first purpose according to the embodiment illustrated in figure 2 is securing the ultrasonic transducer 7 to the top surface 3. Here it is preferred that the coupling agent 6 comprises a component having adhesive properties, it is preferred that this coupling agent also facilitates the creation of the air free interface.
    Therefore according to preferred embodiments, epoxy or silicone grease is used as coupling agent 6 in that these materi als satisfies both purposes of the coupling agent 6. A further advantage of these two coupling agents 6 is their practically non-existent evaporation. Other coupling agents could also be used having low or no evaporation tor long-term installation, or a higher rate of evaporation for short-term installation, though the latter is not expected to be normally desired.
    It should be mentioned that when a guide 15 is used for (at least partly) securing the ultrasonic transducer 7 to either the top surface 3 or bottom surface 5, the coupling agent 6 does not need to comprise an adhesive component, or at least the coupling agent can be less adhesive. This is also true for the situation where a reference measurement has to be made before the actual attachment of the ultrasonic transducer 7 or a single or a few measurements has to be made. In the latter situations, the coupling agent is e.g. a water-soluble or oil-based agent making the ultrasonic transducer easy to remove from the bolt 1 again.
    Summing up to the main feature of the coupling agent 6 is to ensure that no air is between especially the transducer element 9 and the top surface 3 or bottom surface 5, and an additional feature is to secure the ultrasonic transducer 7 to the top surface 3 or bottom surface 5 of the bolt 1.
    The purpose of the communication interface 10 is to provide measurements and, if available, processed data from the ultrasonic transducer 7 to a control device 13. Hence a communication link 14 which is preferably wireless (such as e.g. based on the Bluetooth Smart protocol or other preferably wireless and preferably low-energy protocols) is created between the communication interface 10 and the control device 13.
    According to a preferred embodiment of the invention, the control device 13 communicates with a plurality of ultrasonic transducers 7. The control device 13 may, by means of its own data processors, and / or data storage, process, aggregate, etc. the data received and provide this data to e.g. a wind turbine control system or an external data processor, such as e.g. a server positioned at the location of the party responsible for servicing the wind turbine.
    As mentioned the control device 13 may process the data received from the ultrasonic transducers 7, and it may optionally communicate to other data processors or controi/moniionng systems only in the cases where the received data reveal a change e.g. of length of one or more bolts, if the length of one or more bolts falls short of or exceeds a predefined threshold etc. Such changes could be found e.g. from a comparison between subsequent measurements or to a reference measurement.
    Figures 3a, 3b and 3c illustrate different ways of securing the ultrasonic transducer 7 to either the top surface 3 or the bottom surface 5.
    Figure 3a illustrates that the ultrasonic transducer 7 does not have to cover the entire top surface, nor does it have to be centered on the top surface. As long as it is completely over only the massi ve part of the bolt 1, enabling measuring l ength of the bolt 1 in a direction substantially perpendicular to the top surface 3 / bottom surface 5 the ultrasonic transducer 7 is in most situations located to satisfy its purpose.
    Figure 3b illustrates that a guide 15 may be used to make sure that the ultrasonic transducer 7 measures the length substantially perpendicular to the top surface 3 / bottom surface 5. Another purpose of the guide 15 could be helping securing the ultrasonic transducer 7 to the bolt head 2. This is advantageous in that mounting is easy and done the same way at each bolt 1 and due to the fact that the bolt head 2 is always free and available. This is especially true if the ultrasonic transducer 7 is attached or part of the guide 15. Hence in embodiment’s installation of such guide 15 and thereby ultrasonic transducer 7 only include adding the coupling agent 6 (if not part of the guide 15) and then click or clamp it to the bolt head 2, possibly by using one or more permanent magnets.
    In the same way figure 3c illustrates an ultrasonic transducer 7 which is part of a guide 15 having a threaded part which matches the threaded part 4 of the bolt 1. Hence in the same was as a nut is attached or screwed onto the threaded part 4 of the bolt 1, the guide 15 comprising the ultrasonic transducer 7 can be screwed unto the threaded part 4 of the bolt 1. Thereby only the coupling agent 6 has to be added (if not part of the guide 15) before fastening, and again a very easy and uniform installation of ultrasonic transducers is obtained.
    It should be mentioned that the coupling agent 6 as well as the ultrasonic transducer 7 may also be part of the guide from birth (manufacturing) of the guide 15. Alternatively the coupling agent 6 and the ultrasonic transducer 7 may be applied to the guide 15 before or after mounting the guide 15 to the bolt 1.
    The importance of an easy installation should not be underestimated in that e.g. a tower built of several tower sections may comprise hundreds or thousands of bolts, which would be advantageous to monitor to supplement or avoid the manual inspection, which today is made on a regular basis with production losses as a consequence.
    The two versions of the guide 15 illustrated on figure 3b and 3c, 4 with or without embedded ultrasonic transducer 7 is especially advantageous if the bolt head is not very fiat. i.e. e,g. if a recess or protruding part is part of the top surface 3. One example of this could be the case where the bolt head e.g. is round and has to be tightened by an Allen key or similar. In this situation the alternative would be to apply a thick layer of coupling agent 6 to compensate for the roughness or roundness of the top surface 3 of the bolt head 2. It should be mentioned that the layer of the coupling agent 6 is as small as possible to ease measurements and reduce sources of errors. Hence a layer of coupling agent between the transducer element 9 and the bolt is preferably less than Smilimiter but below' 1 millimeter would often be more preferred.
    The guide 15 will typically be very fast to install e.g. by tighten with a wrench or by hand and the installation is easy to perform in the same way on a plurality of bolts e.g. by use of a torque wrench.
    As set forth in the above description, the present invention relates to a method and an apparatus which by means of an ultrasonic transducer 7 is measuring the length of a bolt 1, and based on the measured bolt length determines if the bolt 1 is sufficiently tightened, e.g. for tightening two wind turbine components together. The ultrasonic transducer 7 is preferably measuring through a coupling agent 6 to ensure an air free interface, and is according to an embodiment attached to the bolt 1 by means of a guide 15.
    Finally it should be mentioned that even though the ultrasonic transducer 7 and the guide 15 is described in relation to monitoring of bolts 1 of a wind turbine, the ultrasonic transducer 7 and guide 15 may be used for measuring bolt length in other applications where bolt length or information derived hereof such as load is relevant. As examples of relevant applications could be mentioned application of any heavy industry, car industry, building and construction industry and so on.
    List 1. bolt 2. bolt head 3. top surface 4. threaded part 5. bottom surface 6. coupling agent 7. ultrasonic transducer 8. power supply 9. transducer element 10. communications interface 1!. emitted ultrasonic signal 12. echo signal 13. control device 14. communications link 15. guide 16. guide threaded part
    权利要求:
    Claims (26)
    [1] 1. Method for automatically retrieving bolt length information of a plurality of bolts (1) securing two parts of a wind turbine, wherein the plurality of bolts (1) are having a bolt head (2) including a top surface (3) and a threaded part (4) including a bottom surface (5) and wherein an ultrasonic transducer (7) comprises a power supply (8), a transducer element (9) and a communication interface (10), the method comprising the steps of: attaching one ultrasonic transducer (7) to either the top surface (3) or the bottom surface (5) of each of the plurality of bolts (1) by means of a coupling agent (6), - performing a plurality of bolt length measurement including retrieving bolt length information by means of the ultrasonic transducer (7) wherein each of the plurality of bolt length measurements are separated in time, and transmitting the bolt length information from the ultrasonic transducer (7) to a control device (13).
    [2] 2. Method according to any of the proceeding claims, wherein the coupling agent (6) comprises an adhesive component.
    [3] 3. Method according to any of the proceeding claims, wherein the coupling agent (6) comprises at least one component of the list comprising: epoxy, silicone grease and oil.
    [4] 4. Method according to any of the proceeding claims, wherein an ultrasonic transducer (7) is attached to at least 50% of the bolts (1) securing the two wind turbine parts, preferably to at least 75% and most preferably to at least 90%.
    [5] 5. Me thod according to any of the proceeding claims, wherein the transducer element (9) is of a type of the list comprising: pitch-catch type, pulse-echo type, through-transmission and phased array type.
    [6] 6. Method according to any of the proceeding claims, wherein the control device (13) comprises a data processor facilitating analyzing the received bolt length information to determine if any of the plurality of bolts are loosened.
    [7] 7. Method according to claim 6, wherein the data processor further facilitates analyzing the received bolt length information to determine load distribution of the bolts (1).
    [8] 8. Method according to any of the proceeding claims, wherein tightening of bolts (!) of the wind turbine is scheduled based on the result of the data processing in the control devi ce (! 3) of the received data.
    [9] 9. Method according to any of the proceeding claims, wherein the control device (13) is located in the wind turbine and facilitates communication with an external data processor.
    [10] 10. Method according to any of the proceeding claims, wherein the bolt length information is retrieved while the wind turbine is in a production mode.
    [11] 11. Method according to any of the proceeding claims, wherein the ultrasonic transducer 7 is equipped with an electronic identification tag or a visible identification tag.
    [12] 12. Method according to any of the proceeding claims, wherein the ultrasonic transducer 7 is equipped with a data storage and / or a temperature sensor and / or a data processor.
    [13] 13. Method according to any of the proceeding claims, wherein a guide (15) is used to ensure that the ultrasonic transducer (7) is secured to the top surface (3) or bottom surface (5) in such a way that the emitted ultrasonic signal (11) from, the transducer element (9) is substantially parallel to the longitudinal direction of threaded part (4) of the bolt (1).
    [14] 14. Method according to claim 13, wherein the guide (15) comprises a thread (16) facilitating mounting the ultrasonic transducer (7) to the bottom surface (5) by mounting the guide (15) by screwing it to the thread part (4) of the bolt (1).
    [15] 15. Use of an ultrasonic transducer (7) for retrieving bolt length information of a bolt (1) in a wind turbine according the method of any of the claims 1-14.
    [16] 16. A guide (15) comprising a guide thread part (16) facilitating mounting of the guide (15) to a threaded part (4) of a bolt (1) and an ultrasonic transducer (7) facilitating monitoring the length of the bolt (!) to which the guide (15) is attached.
    [17] 17. A guide (15) according to claim 16, wherein the guide (15) further comprises a coupling agent (6) facilitating an air free interface between the ultrasonic transducer (7) and a bottom surface (5) of the bolt (1).
    [18] 18. A guide (15) according to claim 16 or 17, wherein bolt length information is retrieved according to the method of any of the claims 1-14.
    [19] 19. Use of a guide (15) comprising an ultrasonic transducer (7) for retrieving bolt length information of a bolt (1) in a wind turbine according any of the claims 16-17.
    [20] 20. A method according to any of the proceeding claims, wherein the method further comprising an initial step of performing a reference measurement of bolt length information, preferably made by the ultrasonic transducer (7).
    [21] 21. A method according to any of the proceeding claims, wherein the reference measurement is made with a temporary ultrasonic transducer coupled to the top surface (3) or the bottom surface (5) with a coupling agent (6).
    [22] 22. Method according to any of the proceeding claims, wherein the coupling agent (6) ensures air free interface between the ultrasonic transducer (7) and the top surface (3) or bottom surface (5).
    [23] 23. Method according to any of the proceeding claims, wherein the coupling agent (6) facilitates a distance of less than 2 millimeter, preferably less than 1 millimeter, most preferably less than 0,5 millimeter between the ultrasonic transducer (7) and the top surface (3) or bottom surface (5).
    [24] 24. Method according to any of the proceeding claims, wherein at least pari of the plurality of the bolts (1) to which an ultrasonic transducer (7) is attached are located between two neighboring bolts (1) which does not have an ultrasonic transducer (7) attached.
    [25] 25. Method according to any of the proceeding claims, wherein at least part of the plurality of the bolts (1) to which an ultrasonic transducer (7) is attached are ha ving one neighboring bolt (1) to which an ultrasonic transducer (7) is attached and another neighboring bolt (1) which does not have an ultrasonic transducer (7) attached.
    [26] 26. Method according to any of the proceeding claims, wherein at least part of the plurality of the bolts (1) to which, an u ltrasonic transducer (7) is attached are having two neighboring bolts to which an ultrasonic transducer (7) is secured.
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    同族专利:
    公开号 | 公开日
    WO2017108051A1|2017-06-29|
    DK179021B1|2017-08-28|
    引用文献:
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    WO2015138562A2|2014-03-11|2015-09-17|Innovation Plus, Llc|System for applying an ultrasonic transducer to a fastener|GB2593743A|2020-03-31|2021-10-06|Tribosonics Ltd|Bolt transducer|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DKPA201570840A|DK179021B1|2015-12-21|2015-12-21|Ultrasonic bolt monitoring|DKPA201570840A| DK179021B1|2015-12-21|2015-12-21|Ultrasonic bolt monitoring|
    PCT/DK2016/050440| WO2017108051A1|2015-12-21|2016-12-16|Ultrasonic bolt monitoring|
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