CN215768360U - Fan blade surface crack monitoring devices - Google Patents

Abstract

The utility model discloses a fan blade surface crack monitoring device which is simple in structure and capable of realizing small crack monitoring, and comprises a plurality of induction coatings coated on the surface of a blade, a diagnosis module and a power supply, wherein the power supply is used for supplying power to the diagnosis module; the conducting layers are strip-shaped, are distributed in the area to be monitored in a roundabout structure or a grid structure, and form a plurality of induction coatings with the first insulating layer and the second insulating layer, the conducting layers in the induction coatings are respectively and electrically connected with the diagnosis module, and the sum of the width of the conducting layers and the gap between every two adjacent conducting layers is larger than or equal to the width of the crack to be detected.

Description

Fan blade surface crack monitoring devices

Technical Field

The utility model relates to the technical field of blades, in particular to a fan blade surface crack monitoring device.

Background

The strength requirement of the wind driven generator on the blade is high, but the surface of the blade of the wind driven generator is easily cracked due to the influence of factors such as the structure, the material, the working frequency, the processing technology, the operating environment and the like of the blade. The occurrence of cracks severely reduces the strain resistance and the service life of the blade. Therefore, the surface of the blade needs to be monitored in the process of generating power by adopting the wind driven generator. Currently, commonly used monitoring methods include: noise monitoring, vibration monitoring, strain monitoring, clearance monitoring, and the like.

However, the existing monitoring method has many defects: noise monitoring means that acoustic sensors are additionally arranged at the engine room or the tower bottom, blade noise is monitored through the acoustic sensors, if the acoustic sensors are additionally arranged to monitor that the blade noise is abnormal, blade cracking is explained, however, the monitoring mode is small in crack area linear velocity, crack openings are not obvious, and effective monitoring cannot be achieved.

The vibration monitoring mainly identifies abnormal impact signals (mainly caused by opening and closing of blade cracks) and frequency caused by blade cracking, but the mode can only identify larger cracks and cannot realize accurate monitoring of fine cracks, and for key areas of partial positions such as main beams, blade root areas and the like, when cracks crack greatly, the problems of high maintenance difficulty, serious blade damage and the like exist.

The strain monitoring is realized by adopting a strain gauge or fiber bragg grating monitoring based on the change of the peripheral stress field of the blade after the crack is expanded, but the change range of the stress field around the crack is a range smaller than the size of the crack, the blade has larger periodic stress change in the rotating process, the position of the crack is uncertain, more measuring points are needed to ensure the monitoring accuracy, and the monitoring cost is increased by arranging a plurality of measuring points.

The clearance monitoring is mainly used for judging the torsional deformation of the blade through image clearance monitoring, for example, the patent number is "CN 201610826920.8", and the patent name is "the blade state monitoring device and the monitoring method of the wind generating set", in the patent, the torsional state of the blade is mainly judged through the distance between a monitoring sensor and a blade suction surface, so as to judge whether the torsional deformation of the blade is overlarge, but the clearance monitoring is mainly used for detecting the torsional deformation of the blade tip, the blade and the maximum chord length of the blade, the blade crack cannot be accurately monitored in real time, when the crack influence can be identified on the blade tip distance, the size of the crack generated at the moment is larger, the blade is broken by being endangered, and the maintenance difficulty is larger.

SUMMERY OF THE UTILITY MODEL

Aiming at the problems in the prior art, the utility model provides a device and a method for monitoring surface cracks of a fan blade and a method for coating an induction material, which have simple structures and can realize effective monitoring of small opening cracks.

In order to achieve the purpose, the utility model adopts the following technical scheme:

the fan blade surface crack monitoring device comprises a plurality of induction coatings coated on the surface of a blade, a diagnosis module and a power supply, wherein the power supply is used for supplying power to the diagnosis module; the conducting layer is strip-shaped, is distributed in the area to be monitored in a roundabout structure or a grid structure, forms a plurality of induction coatings with the first insulating layer and the second insulating layer, and is electrically connected with the diagnosis module respectively; the sum of the width of the conducting layers and the gap between two adjacent conducting layers is larger than or equal to the width of the crack to be detected.

It is further characterized in that the method further comprises the steps of,

the diagnosis module is in communication connection with the external terminal through the communication control module;

the conducting layer is made of conducting paint;

the conducting layer and the crack to be detected are arranged at a certain angle;

the conducting layer is vertical to the crack to be detected;

the circuitous structure comprises a plurality of first vertical coatings and a plurality of first transverse coatings which are distributed at intervals in parallel, wherein the first transverse coatings are distributed at intervals, and the first vertical coatings are connected end to end through the first transverse coatings to form the circuitous structure;

the grid structure comprises two sets of said inductive coatings: the induction heating device comprises a first induction coating and a second induction coating, wherein the first induction coating and the second induction coating are distributed in a crossed mode at a certain angle to form a grid structure, and the first induction coating and the second induction coating are insulated;

the diagnostic module comprises a wiring terminal, a first layer of logic circuit, a second layer of logic circuit, a reset circuit, a controller and an alarm device, wherein the alarm device comprises a plurality of alarm lamps and a display screen, and the number of the alarm lamps is consistent with that of the induction coating and the relays; the connecting terminal is electrically connected with the conductive layer of the induction coating, the connecting terminal is sequentially connected with the first layer of logic circuit, the second layer of logic circuit and the controller, the first layer of logic circuit comprises a plurality of relays, the second layer of logic circuit comprises an AND gate, the conductive layer in each induction coating is respectively and electrically connected with the input end of the AND gate, an alarm lamp and a reset circuit through one relay, and the output end of the AND gate is connected with the controller;

the power supply comprises an external power supply and an internal power supply, the internal power supply comprises a solar cell and a storage battery, the solar cell converts solar energy into electric energy, and the storage battery is used for storing the electric energy generated by the fan.

A fan blade surface crack monitoring method is realized based on the monitoring device and is characterized by comprising the following steps: s1, dividing a region to be monitored on the surface of the blade into a plurality of sub-regions;

s2, coating at least one group of induction coating on the surface of each subregion;

s3, electrically connecting the conductive layer in the induction coating with a diagnostic module;

s4, detecting whether the conducting layer is powered off or not through the diagnosis module, if the conducting layer is powered off, indicating that the sub-region has a crack, and entering the step S5;

and S5, the diagnosis module gives an alarm and sends power-off information to the external terminal through the communication control module.

And S6, acquiring the width of the crack through the external terminal.

It is further characterized in that the method further comprises the steps of,

in step S4, the diagnosis module detects whether the conductive layer is powered off, and the diagnosis mode of the diagnosis module includes: detecting whether the conducting layer of each subarea is broken or not through the first layer of logic circuit, if the subarea is cracked, the conducting layer is broken, the switch of the corresponding relay in the first layer of logic circuit is closed, the signal output is high level and is in a holding state until manual reset, meanwhile, the corresponding alarm lamp in the alarm device is on to prompt a worker that the subarea is cracked, if the subarea is not cracked, the switch of the corresponding relay is off, the alarm lamp is not on, and no alarm is given;

when any input port in the first layer of logic circuit detects that a conducting layer is broken and outputs a high level signal, the second layer of logic circuit receives the high level signal, converts the low level of the initial state into a high level, and sends the high level signal to the controller, so that a crack appears in a certain subregion of the surface of the blade;

and the controller sends the power-off information to the external terminal through the communication control module.

An induction coating method, wherein the induction coating is coated on the surface of a blade and is used for monitoring cracks on the surface of the blade, the induction coating comprises a first induction coating and/or a second induction coating, and the first induction coating method comprises the following steps: a1, coating a first insulating layer on a region to be monitored on the surface of the blade;

a2, after the first insulating layer is cured, coating a conductive layer on the outer surface of the first insulating layer;

a3, after the conducting layer is dried completely, detecting the conducting layer to ensure that the conducting layer can conduct electricity;

a4, leading out signal wires at two ends of the conductive layer;

and A5, coating a second insulating layer on the outer surfaces of the conductive layer and the first insulating layer.

It is further characterized in that the method further comprises the steps of,

the first insulating layer and the second insulating layer are both epoxy resin or fiber reinforced resin;

the colors of the first insulating layer, the second insulating layer and the conducting layer are different, and are all different from the surface color of the blade;

the conducting layer is made of conducting paint;

the conductive paint is made of copper;

in step S3, the detection method of the conductive layer is: detecting the voltage and the current of the conducting layer by adopting a universal meter or a bridge detection circuit, calculating the resistance of the conducting layer according to the voltage and the current, evaluating the resistance, judging whether the resistance meets the standard, entering the step A4 if the resistance meets the standard, and otherwise, performing paint repair on the conducting layer;

in the step A4, the signal wire is an electrode, the conductive paint is connected with the electrode through conductive silver paste, and the outer surface of the electrode is fixed through epoxy resin or fiber reinforced resin;

the method further comprises a step A6 of coating a second induction coating on the surface of the second insulation layer, so that the conductive layer in the first induction coating and the conductive layer in the second induction coating are crossed to form a grid structure, and the first induction coating and the second induction coating are insulated by the second insulation layer in the first induction coating and the first insulation layer in the second induction coating.

By adopting the structure of the utility model, the following beneficial effects can be achieved: this application fan blade surface crack monitoring devices contains response coating, diagnosis module, and the response coating coats in the monitoring area of treating on blade surface for whether the crackle appears on detecting the blade surface, if appear, then the conducting layer in the response coating is along with the crackle fracture, and the conducting layer outage, diagnosis module detect this outage signal, show that the monitoring area of treating on blade surface appears the crackle, thereby realized blade surface crack detection.

The conducting layer in the induction coating of this application waiting to monitor the region is the strip, and the conducting layer is circuitous structure or grid structure and distributes and form a plurality of induction coating district waiting to monitor the region, wait the width less than or equal to conducting layer of crack and the sum of clearance between two adjacent conducting layers, if wait to monitor the region and appear the crack, and crack width surpasss conducting layer width and two adjacent conducting layers between the clearance sum, must make the conducting layer fracture that this crack passed through, the conducting layer outage. Because the width of the conducting layer and the gap between two adjacent conducting layers are set according to the width of the crack, even if the crack is small and exceeds the sum of the width of the conducting layer and the width of the gap, the conducting layer can break along with the crack, thereby realizing effective monitoring of the crack of the small opening, and preventing the serious damage problem of the blade caused by the untimely crack discovery and the overlarge crack.

Drawings

FIG. 1 is a schematic top view of an inductive coating of the present invention;

FIG. 2 is a schematic cross-sectional view of an induction coating and blade according to the present invention;

FIG. 3 is a schematic view of the monitoring device according to the present invention;

FIG. 4 is a schematic diagram of the diagnostic module of the present invention;

FIG. 5 is a schematic cross-sectional view of a blade according to the present invention.

Detailed Description

Referring to fig. 1, 2, 3 and 4, the fan blade surface crack monitoring device comprises a plurality of induction coatings 1 coated on the blade surface, a diagnosis module 2, a power supply 3 and a communication control module 4, wherein the power supply 3 is electrically connected with the diagnosis module 2 and used for supplying power to the diagnosis module 2, the diagnosis module 2 is in communication connection with an external terminal 5 through the communication control module 3, and the external terminal 5 is a central control system or a remote monitoring system. The diagnosis module 2, the power supply 3 and the communication control module 4 are welded and fixed on a flexible board or a PCB board, and are packaged and fixed on the surface of the root part of the blade or in the blade, or are integrated in a control box and installed at proper positions such as a blade root cover plate.

The power supply 3 comprises an external power supply and an internal power supply, the external power supply comprises a solar cell and a storage battery, the solar cell converts solar energy into electric energy, the storage battery is used for storing the electric energy generated by the fan, the external power supply is AC 200V or DC 24V or DC 12V which is accessed from the hub through the blade root, preferably a DC power supply, the internal power supply converts the solar energy into the electric energy through the solar cell or stores the electric energy in the storage battery through the gravity swing rotation of the blade, for the occasion that the external power supply can be continuously stabilized for a long time, the external power supply is adopted for continuous power supply, when the power supply condition of the external power supply is deficient, the internal power supply is adopted, when the monitoring blade rotates, the external terminal 5 sends a control signal to the internal power supply through the communication control module 4, the internal power supply is controlled to be timed within one day or continuously supplied for a period of time, and the continuous power supply time is at least longer than the period of one rotation of the blade, the conductive paint is prevented from being broken due to conduction when the cracks are in a closed state, so that the problems of misdiagnosis and false alarm are avoided. In this embodiment, the communication control module 4 is any one of network communications such as WIFI wireless communication, signal line, 4G/5G/LoRa.

The induction coating 1 comprises a first insulating layer 11 coated on the surface of the blade and a second insulating layer 12 coated on the surface of the first insulating layer 11, a conductive layer 13 is coated between the first insulating layer 11 and the second insulating layer 12, the conductive layer 13 is conductive paint, the conductive layer 13 is in a strip shape, and the distribution structure of the conductive layer 13 on the surface of the blade comprises at least the following two forms:

embodiment one of the conductive layer distribution: the conducting layer 13 is distributed on the to-be-monitored area of the surface of the blade 6 in a roundabout structure to form a plurality of induction coating areas, the roundabout structure comprises a plurality of first vertical coatings 131 and a plurality of first transverse coatings 132 which are distributed at intervals in parallel, the first transverse coatings 132 are distributed at intervals, and the first vertical coatings 131 are connected end to end through the first transverse coatings 132 to form the roundabout structure. Each induction coating area is electrically connected with the diagnosis module 2 respectively; the sum of the width of the conductive layer 13 and the gap between two adjacent conductive layers 13 is greater than or equal to the width of the crack to be detected, and in this embodiment, the conductive layer 13 is perpendicular to the crack to be detected.

Example two of conductive layer distribution: the conducting layer 13 is distributed on the surface of the blade 6 in a grid structure in the area to be monitored to form a plurality of induction coating areas, and the grid structure comprises two groups of induction coatings: the first induction coating and the second induction coating are distributed in a crossed mode at a certain angle to form a grid structure, and the first induction coating and the second induction coating are insulated, in the embodiment, the first induction coating and the second induction coating are distributed vertically, the conducting layers in the first induction coating and the second induction coating are distributed at a certain angle with the crack to be detected, the angle ranges from 30 degrees to 90 degrees, the angle is reasonably selected according to actual requirements, the surface crack of the blade can be bent or bent, when the initial crack is perpendicular to the first induction coating, the conducting layer in the first induction coating is broken, and when the subsequent crack is turned, the conducting layer in the second induction coating is broken, so that the accurate detection of the bent crack is realized, therefore, compared with the detection mode of only adopting the zigzag first induction coating, the accurate detection mode of the bent crack can be realized by the superposition mode of the first induction coating and the second induction coating, the detection is more accurate.

Referring to fig. 4, the diagnostic module 2 includes a connection terminal 21, a first layer logic circuit 22, a second layer logic circuit 23, a reset circuit, a controller 24 and an alarm device 25, the connection terminal is electrically connected with the conductive layer of the induction coating, the connection terminal 21 is sequentially connected with the first layer logic circuit 22, the second layer logic circuit 23 and the controller 24, the first layer logic circuit 22 includes a plurality of relays, the second layer logic circuit 23 includes an and gate, the alarm device 25 includes a plurality of alarm lamps, the number of the alarm lamps is consistent with the number of the relays, the conductive layer of each induction coating area 10 is respectively electrically connected with the input end of the and gate, one alarm lamp and the reset circuit through one relay, and the output end of the and gate is connected with the controller; the alarm device 25 further comprises a liquid crystal display screen and an external terminal, the external terminal can be connected with other existing alarm devices (such as a buzzer), and the liquid crystal display screen is electrically connected with the controller 24.

A fan blade surface crack monitoring method is realized based on the monitoring device, and the monitoring method specifically comprises the following steps: s1, for the blade crack monitoring requirement, dividing a to-be-monitored area on the surface of the blade 6 into a plurality of sub-areas according to a monitored object, and cleaning each sub-area, removing surface coatings and the like;

s2, coating at least one group of induction coatings on the surface of each subarea; in this embodiment, a group of inductive coatings is respectively disposed on the trailing edge region 61, the leading edge region 62, the pressure surface 63, and the suction surface 64;

s3, electrically connecting the conducting layer signal wire 14 in each induction coating with the diagnosis module 2;

s4, detecting whether the conducting layer is powered off through the diagnosis module 2, if the conducting layer is powered off, indicating that the sub-region has cracks, entering the step S5, and if the conducting layer is not powered off, continuously monitoring through the diagnosis module 2;

whether the conductive layer 13 is powered off is detected by the diagnostic module 2, and the diagnostic mode of the diagnostic module 2 comprises the following steps: detecting, by the first layer logic circuit 22, whether the conductive layer 13 of each sub-area is broken, in particular: if the sub-region has cracks, the conductive layer 13 in the corresponding induction coating is broken, the switch of the corresponding relay in the first layer of logic circuit 22 is closed, the signal output end of the relay is detected to be at a high level (the high level is indicated as '1') at the moment, the relay is in a holding state until the relay is manually reset, meanwhile, a corresponding alarm lamp in the alarm device is turned on to prompt a worker that the sub-region has cracks, and if the sub-region has no cracks, the switch of the corresponding relay is in a normally open state, the alarm lamp is not turned on, and no alarm is given. The manual reset button is arranged at a proper position, and when cracks are repaired or inspected and eliminated, the reset button of the reset circuit is manually pressed, so that the switch of the relay is switched off, and subsequent detection is continued.

The initial state of the second layer logic circuit 23 is low (low level is indicated as "0"), when any input port in the first layer logic circuit 22 detects that the conductive layer is broken, i.e. outputs a high level signal, i.e. when the second layer logic circuit 23 detects that any relay of the first layer logic circuit 22 outputs a high level signal, the second layer logic circuit 23 switches from the low level of the initial state to high level and sends a high level signal to the controller, indicating that a crack has occurred in a certain sub-area of the blade surface.

When a certain subregion on blade surface appears the crackle, controller control liquid crystal display screen display high level signal "1", suggestion staff blade surface appears the crackle, and after the staff received the signal that the crackle appears on blade surface, accessible alarm lamp judged specifically that which subregion appears the crackle, and the staff of being convenient for locks blade crackle area fast.

And S5, the diagnosis module 2 gives an alarm, and meanwhile, the diagnosis module 2 sends the power-off information to an external terminal through the communication control module.

And S6, acquiring the width of the crack through the external terminal, wherein the width of the crack is larger than or equal to the sum of the width of the conducting layer and the gap between two adjacent conducting layers.

In the step S2, the induction coating is coated on the surface of the blade to monitor cracks on the surface of the blade, the induction coating includes a first induction coating and/or a second induction coating, and the coating method of the first induction coating includes: a1, coating a first insulating layer on a region to be monitored on the surface of the blade; the first insulating layer is made of epoxy resin or fiber reinforced resin, and the color of the first insulating layer is A;

a2, after the first insulating layer is cured, coating a conductive layer on the outer surface of the first insulating layer, wherein the conductive layer is conductive paint, and the color of the conductive paint is C; for example, for the blade surface, as can be known from experience, the structural crack is generally perpendicular to the blade span direction (i.e. the blade length direction), then the vertical coating (including the first vertical coating) of the conductive paint is perpendicular to the crack, the transverse coating connects the vertical coatings in series, according to the operation and maintenance guidance, if the economic length of crack repair is D, the sum of the width of the coating and the width of the gap between the coatings is less than or equal to D, and the material of the conductive paint in this embodiment is copper. In the above steps a1 and a2, the color of the color a, the color B and the color C are different, and are also different from the color of the area to be monitored on the surface of the blade, so as to be distinguished from the color of the measured object.

And A3, after the conductive paint is dried completely, detecting the conductive layer to ensure that the conductive layer can conduct electricity. The detection mode of the conducting layer is as follows: detecting the voltage and the current of the conducting layer by adopting a universal meter or a bridge detection circuit, calculating the resistance of the conducting layer according to the voltage and the current, evaluating the resistance, judging whether the resistance meets the standard, entering the step A4 if the resistance meets the standard, and otherwise, performing paint repair on the conducting layer;

a4, leading out signal lines at the electrode areas at the two ends of the conductive layer, namely connecting the electrodes at the two ends of the copper strip through conductive silver paste and other materials, and fixing the outside by using epoxy resin or glass fiber reinforced resin;

and A5, coating a second insulating layer on the outer surfaces of the conductive layer and the first insulating layer, wherein the second insulating layer is made of epoxy resin or fiber reinforced resin and has the color of B. And after the second insulating layer is cured, paint repair is carried out according to the requirement.

As another embodiment of the application of the induction coating, a grid structure is formed by overlapping the first induction coating and the second induction coating, that is, the induction coating of the second embodiment includes: in the embodiment, the coating method further includes a step A6 of coating a second inductive coating on the surface of the second insulating layer, so that the conductive layer in the first inductive coating and the conductive layer in the second inductive coating intersect to form a grid structure.

In practical implementation, according to the strength analysis result of the blade, a structural weak position is determined, the weak position is a dangerous area which can generate cracks, and a potential dangerous area of the blade is set as an area to be monitored, as shown in fig. 5, the area to be monitored comprises a trailing edge area 61, a leading edge area 62, a pressure surface 63 and a suction surface 64. According to actual requirements, the induction coating can be coated inside the blade at the same time, the induction coating inside the blade is generally coated on the front edge bonding part and the rear edge bonding part of the blade, the area inside the blade can be cleaned and then directly constructed for coating the induction coating, and the conductive paint (taking the induction coating as an example in the embodiment) of the sub-area of the front edge bonding part and the rear edge bonding part inside the blade is vertical to the length direction of the blade. The pressure surface 63 and the suction surface 64 are also divided into a plurality of sub-areas, and each sub-area is coated with an induction coating, for example, in the embodiment where the induction coatings are distributed in a winding shape, the first vertical coating direction of each sub-area is distributed perpendicular to the length direction of the blade.

Technical analysis shows that the blade can be repaired well and quickly when the crack length of the blade does not exceed 12cm, so that the sum of the width of the coating and the distance between the coatings is set to be less than 12cm, the sum of the width of the coating and the distance between the coatings is set to be 5cm in the embodiment, and thus, cracks of any 5cm or more can penetrate through at least one coating, and alarm is triggered. In this embodiment, the photovoltaic panel, the micro-battery, the diagnostic module, the communication control module, and the antenna thereof are etched or welded on the flexible circuit board, the circuit board is sealed and connected to the surface of the root of the blade, and the solar cell, the battery, the diagnostic module, the communication control module, the antenna, and the circuit board are encapsulated by the housing. In the process of diagnosis by using the diagnosis module, the second layer of logic circuit adopts an AND gate with multiple inputs and 1 output (namely, one output end of a plurality of input ends), as long as high level output exists in the first layer of logic circuit at the upper layer, the output of the AND gate is a high level signal, the corresponding output relay keeps high level output, and the relay can be reset to a low level state only through a manual reset button of a reset circuit. The antenna in the communication control module is packaged in the shell, so that the influence of the antenna on the appearance of the blade is reduced, and meanwhile, the damage of the antenna which is protruded in the transportation process of the blade is avoided. The external terminal sends a signal to the internal power supply through the communication control module, the internal power supply supplies power once every 1 hour, and the internal power supply keeps for one minute every time, so that the blades rotate for multiple circles in the detection process, and false alarm caused by temporary communication of the conductive paint circuit due to the fact that the cracks are closed in too short monitoring time is avoided.

When a crack in a certain area propagates through the coating line, the sub-area is caused to be broken, so that the sub-area alarm lamp is triggered to be turned on and the blade crack alarm is triggered. When operation and maintenance personnel know that the specific blade of the specific unit gives an alarm through the central control system or the remote monitoring system, verification is required firstly (no matter what kind of monitoring is carried out, the personnel are required to determine the specific condition of the crack). Because the specific unit and the blades are known, the blades can be in a posture convenient to detect by rotating the wind wheel after a person operates the wind wheel. The alarm lamp is installed in blade wheel hub's root, and personnel can look over the alarm lamp at the root after getting into wheel hub, confirm the subregion at crackle place through the alarm lamp to confirm the crackle position relatively fast and develop the inspection. The system not only avoids higher cost caused by monitoring and determining specific positions by a large number of measuring points, but also is superior to the conventional monitoring system which only reports the abnormal state of the blade and needs large-scale manual investigation. Because for the crackle, the operation and maintenance personnel can quickly position through means such as blade inside visual inspection, cabin top visual inspection, telescope, unmanned aerial vehicle and the like only after determining the approximate position, and arrange maintenance according to the whole failure condition.

After the operation and maintenance personnel repair the cracks, the slope of the residual area of the induction coating is ground to form a conductive paint surface, and then the induction coating is paved again. Because the first insulating layer, the conductive paint and the second insulating layer adopt different colors, the number of the polishing layers can be accurately controlled in the repairing process. Or the conductive paint in the area is paved again by means of the original electrode joint, the second insulating layer is coated after the conductive paint is detected, then the reset button of the diagnosis module is pressed, the alarm is released, and the monitoring is continued.

The crack monitoring device and the crack monitoring method have the following technical advantages that: 1. this application adopts many subregion independent monitoring, reduces to implement the construction degree of difficulty that whole response coating brought on a large scale (once do one in the prior art on a large scale continuous construction, the degree of difficulty is big, the quality is difficult for guaranteeing), has improved positioning accuracy (the response coating that covers on a large scale among the prior art can't fix a position concrete crack position). Meanwhile, monitoring results of all subregions in the crack monitoring device are prompted by an alarm lamp, so that operation and maintenance personnel can quickly position specific positions. The second layer of logic circuit can output the alarm of all the subareas of the whole blade through one channel, thereby saving the data acquisition cost.

2. The sensor is usually arranged on the blade in the prior art, the sensor connecting circuit is required to be connected with a monitoring system, the circuit structure is complex, the crack can be detected by setting the induction coating, the diagnosis module for monitoring the conductivity of the induction coating is integrated with the power supply and the communication control module in the same shell, the power supply of the internal power supply can be realized, the energy is saved, the structural design is simple, and the installation is convenient and fast.

3. The induction coating is thin, and key positions can be monitored in the blade manufacturing process, such as positions which are not easy to observe, such as blade tip bonding joints, embedded bolt sleeve bonding and the like; the induction coating adopts different colors, thereby being convenient for construction and ensuring the construction quality.

4. The coating substrate of the induction coating adopts epoxy resin or fiber reinforced resin, so that structural load can be better transferred, and under the condition that a measured object is cracked, the conductive medium is not broken due to the flexibility of the substrate, so that the leakage alarm is realized. And the insulation property of the epoxy resin or the fiber reinforced resin can be applied to the tested object of carbon fiber and metal material.

5. First response coating, the second response coating of this application superpose the setting mutually to avoided the blind area that the clearance leads to between the subregion, and the parallel coating of crackle in complicated crackle initiation area and leak the warning. For example, a crack perpendicular to the longitudinal direction of the blade exists near the trailing edge of the root and a crack parallel to the longitudinal direction of the blade is caused by the separation of the bonding area, so that the first induction coating in the horizontal longitudinal direction of the blade can be laid first, and then the second induction coating in the vertical longitudinal direction of the blade can be laid in an overlapping manner. Because whole response coating is thinner, even a plurality of response coatings stack, can follow the fracture when the measured object crackle appears, improved the monitoring accuracy. The coating mode of laying the first induction coating and the second induction coating in a superposition mode is given, and in practical application, the number of layers of the induction coatings and the angle between the two adjacent induction coatings can be flexibly set according to actual requirements.

The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and concepts of the utility model are to be considered within the scope of the utility model.

Claims (5)

1. The fan blade surface crack monitoring device comprises a plurality of induction coatings coated on the surface of a blade, a diagnosis module and a power supply, wherein the power supply is used for supplying power to the diagnosis module; the conducting layer is strip-shaped, is distributed in a region to be monitored in a roundabout structure or a grid structure, forms a plurality of induction coatings with the first insulating layer and the second insulating layer, and is electrically connected with the diagnosis module respectively; the sum of the width of the conducting layers and the gap between two adjacent conducting layers is larger than or equal to the width of the crack to be detected.

2. The fan blade surface crack monitoring device of claim 1, further comprising a communication control module and an external terminal, wherein the diagnosis module is in communication connection with the external terminal through the communication control module, and the conductive layer and the crack to be detected are arranged at a certain angle.

3. The fan blade surface crack monitoring device of claim 1 or 2, wherein the circuitous structure comprises a plurality of first vertical coatings and a plurality of first transverse coatings which are distributed at intervals in parallel, and the first transverse coatings are distributed at intervals, and the first vertical coatings are connected end to end through the first transverse coatings to form the circuitous structure; the grid structure comprises two sets of said inductive coatings: the induction heating device comprises a first induction coating and a second induction coating, wherein the first induction coating and the second induction coating are distributed in a crossed mode at a certain angle to form the grid structure, and the first induction coating and the second induction coating are insulated.

4. The fan blade surface crack monitoring device of claim 3, wherein the diagnosis module comprises a connection terminal, a first layer of logic circuit, a second layer of logic circuit, a reset circuit, a controller and an alarm device, the alarm device comprises a plurality of alarm lamps and a display screen, the connection terminal is electrically connected with the conductive layer of the induction coating, the connection terminal is sequentially connected with the first layer of logic circuit, the second layer of logic circuit and the controller, the first logic circuit comprises a plurality of relays, the second layer of logic circuit comprises an AND gate, the conductive layer in each induction coating is electrically connected with the input end of the AND gate and the alarm lamp through one relay, and the output end of the AND gate is electrically connected with the controller; the number of the alarm lamps is consistent with that of the induction coating and the relays; the power supply comprises an external power supply and an internal power supply, the internal power supply comprises a solar cell and a storage battery, the solar cell converts solar energy into electric energy, and the storage battery is used for storing the electric energy generated by the solar cell.

5. The inductive coating application method of claim 4, wherein the conductive layer is a conductive paint; the conductive paint is made of copper.

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