KR102554600B1 - Ring type displacement measuring device - Google Patents

Abstract

A ring-type displacement gauge and system that can be easily installed on the inner surface of a steel pipe are disclosed. According to one aspect of the present invention, the ring frame fixedly installed in a circular shape along the inner surface of the steel pipe; Deformation sensors disposed on the ring frame individually or in a pair to face each other and installed in a circular shape along the wall of the steel pipe to detect a voltage according to the deformation of the steel pipe; and an electric unit for supplying power to the deformation sensor and receiving a signal therefrom to measure the displacement of the bore of the steel pipe.

Description

Ring type displacement measuring device}

The present invention relates to a ring-type displacement gauge, and more particularly, to a ring-type displacement gauge that can be easily installed on the inner surface of a steel pipe.

In general, a ring-type displacement gauge is installed in a circular shape along the inner surface of a large circular steel pipe and was developed to measure the deformed displacement to ensure safety. An example of an object of such a ring-type displacement gauge is a tower of a wind power generator.

A wind power generator is a representative eco-friendly energy source that rotates blades by wind and generates power with rotational force. These wind power generators are steadily installed in places with abundant wind, such as highlands and seas, and are faithfully playing a role as an eco-friendly energy source. As the number of installed wind turbines increases, interest in new construction and maintenance of renewable wind turbine towers has recently increased. There are several maintenance items of a wind turbine, and among them, there is an item for measuring the displacement of the wind turbine tower in terms of stability.

In the case of a wind turbine tower, since the diameter of the steel pipe is large and a common hole must be formed so that a person can go up and down from the bottom of the tower to the top for maintenance, it is necessary to improve it with a considerably large diameter bore displacement measuring device. Above all, as the tower of a wind power generator, which is a national social infrastructure, is damaged and accidents leading to the collapse of the generator occur frequently, interest in the cause and maintenance has increased, and active research is being conducted recently.

It is predicted that the main cause of wind tower collapse is collapse due to stress concentration at the tower connection. If such deformation can be predicted and monitored in advance, collapse accidents can be reduced.

Although the displacement of the steel pipe of the wind tower according to this example needs to be measured, it is also necessary to measure the displacement of a general steel pipe widely used as a structure to ensure safety.

Registered Patent No. 10-1128276

According to the present invention, it is intended to provide a ring-type displacement meter that can accurately and efficiently measure the deformation of a steel pipe that provides a supporting force like a normal frame.

According to the present invention, when a tower is deformed by a ring-type displacement meter installed in a circular shape along the inner wall of a steel pipe, a ring-type displacement meter that measures and converts the shape of a circular ring into an elliptical shape and converts it into displacement is to be provided. .

According to one aspect of the present invention, the ring frame fixedly installed in a circular shape along the inner surface of the steel pipe; Deformation sensors disposed on the ring frame individually or in pairs to face each other and installed in a circular shape along the wall surface of the steel pipe to detect a voltage according to deformation of the steel pipe; and an electric unit for supplying power to the deformation sensor and receiving a signal therefrom to measure the displacement of the bore of the steel pipe.

At this time, the ring frame may further include an auxiliary fixing unit for fixing so as not to deviate from the installation position of the steel pipe.

At this time, the auxiliary fixing portion may be a ring-shaped fixing member fixed to the inner surface of the steel pipe at the bottom thereof to support the ring frame.

At this time, the auxiliary fixing portion may be a plurality of fixing members fixed at a predetermined angle to the inner surface of the steel pipe at the lower end of the ring frame.

At this time, the auxiliary fixing portion may be fixed to the inner surface of the steel pipe by an adhesive.

According to the above configuration, the ring-type displacement gauge according to the present invention can accurately and efficiently monitor the deformable weak part of the steel pipe and warn an abnormal situation in real time.

1 is a perspective view of a wind turbine tower equipped with a ring-type displacement gauge according to an embodiment of the present invention;
2 is a perspective view showing an example of a broken wind turbine tower.
3 is a plan view of a ring-type displacement gage according to a first embodiment of the present invention.
4 is a perspective view of a ring-type displacement gage according to a first embodiment of the present invention.
5 is a longitudinal cross-sectional view of a portion where a ring-type displacement gauge according to a first embodiment of the present invention is installed.
6 is a longitudinal cross-sectional view of a ring-type displacement gage according to a second embodiment of the present invention.
7 is a plan view of a ring-type displacement measuring device according to a third embodiment of the present invention.
8 is a structural analysis model of a ring-type displacement gauge with a diameter of 150 mm according to a fourth embodiment of the present invention.
9 is a structure analysis modification diagram of a ring-type displacement gauge having a diameter of 150 mm according to a fourth embodiment of the present invention.
10 is a structural analysis model of a ring-type displacement gage having a diameter of 350 mm according to a fifth embodiment of the present invention.
11 is a structure analysis modification diagram of a ring-type displacement measurement charge having a diameter of 350 mm according to a fifth embodiment of the present invention.
12 to 14 are design drawings of a prototype of a ring-type displacement meter according to a fifth embodiment of the present invention. FIG. 12 is a prototype main body drawing, FIG. 13 is a prototype connecting part block drawing, and FIG. 14 is a prototype connecting part cover drawing, respectively. show
15 is a photograph of a prototype ring-type displacement gauge with a diameter of 350 mm.
16 is a photograph of hydraulically fixing a circular steel pipe for test evaluation.
17 is a photograph of a ring-type displacement gauge installed inside a steel pipe.
18 is a photograph of the displacement gauge installed outside the steel pipe connection.
19 is a displacement-time graph as an experimental result of applying a 350 mm diameter steel pipe structure.
20 is a load-displacement graph as an experimental result of applying a 350 mm diameter steel pipe structure.
21 is an analysis result of applying a 350 mm diameter steel pipe structure.

Words and terms used in this specification and claims are not construed as limited in their ordinary or dictionary meanings, but in accordance with the principle that the inventors can define terms and concepts in order to best describe their inventions. It should be interpreted as a meaning and concept that corresponds to the technical idea.

Therefore, the embodiments described in this specification and the configurations shown in the drawings correspond to a preferred embodiment of the present invention, and do not represent all the technical ideas of the present invention, so that the corresponding configurations are various to replace them at the time of filing of the present invention. There may be equivalents and variations.

In this specification, terms such as "include" or "have" are intended to describe the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

A component being in the "front", "rear", "above" or "below" of another component means that it is in direct contact with another component, unless there are special circumstances, and is "in front", "rear", "above" or "below". It includes not only those disposed at the lower part, but also cases in which another component is disposed in the middle. In addition, the fact that certain components are “connected” to other components includes cases where they are not only directly connected to each other but also indirectly connected to each other unless there are special circumstances.

Hereinafter, an embodiment in which the ring-type displacement meter according to the present invention is applied to a wind power generator tower will be described with reference to the drawings.

First of all, referring to FIGS. 1 and 2, the ring-type displacement gauge 100 according to the present invention will be mostly installed at the joint of the steel pipe 10. This is because most of the collapse accidents of the steel pipe 10 usually occur at the joint. Of course, for this reason, the hole displacement measuring device is not installed only at the joint.

Referring to FIGS. 1 to 5 , the ring-type displacement meter 100 according to the first embodiment of the present invention includes two pairs of ring frames 111, a plurality of strain sensors 112, and an electric unit 113. can include

At this time, one ring frame 111, two deformation sensors 112, and the electrical part 113 are modularized as one set, and these four ring modules 110-140 have different heights. ) installed on the inner surface to form a measuring device.

Referring to FIGS. 1 to 5 , the ring frame 111 may be installed horizontally by being in close contact with the inner surface of the steel pipe 10 .

At this time, the ring frame 111 may be made of a band type so as to be in close contact with the inner surface of the steel pipe 10.

At this time, the ring frame 111 can be made of various materials so as to have elasticity, and here, it is custom-made to correspond to the inner diameter of the inner surface of the steel pipe 10 to be installed.

In this case, the ring frame 111 may be made of a metal material having elasticity, but may be made of synthetic resin. Since the ring frame 111 measures internal hole displacement for a long time after installation, it is preferable to select a durable material.

At this time, since the ring frame 111 has two deformation sensors 112 installed in one ring frame 111, four ring frames 111 may be installed in a set form based on the joint. Of course, the diameter of the ring frame 111 may be manufactured differently according to the increase or decrease of the inner diameter of the steel pipe 10.

At this time, the ring frame 111 may be designed to be tightly fixed on its own without forming fastening holes for fastening to the steel pipe 10. The outer surface of the ring frame 111 may be fixed using adhesive or adhesive tape, or may be fixed mechanically or physically. Here, an auxiliary fixing part described later may be provided for more secure fixation.

Referring to FIGS. 1 to 5 , the deformation sensors 112 are arranged in pairs facing each other on each of the ring frames 111, and one pair of ring frames 111 and the other pair have a phase difference of 90 degrees. It is arranged so as to be in close contact with the steel pipe 10, so that the voltage according to the deformation of the steel pipe 10 can be sensed.

In this case, two deformation sensors 112 may be installed to each of the four ring frames 111 to have a phase difference of 180 degrees.

At this time, since two deformation sensors 111 are installed in each of the four ring frames 111, a total of eight may be installed.

At this time, for example, among the four ring modules 110-140, the deformation sensors of the upper and lower ring modules 110 and 140 are arranged in the north-south direction, and the deformation sensors of the remaining middle ring modules 120 and 130 can be arranged in the east-west direction.

At this time, referring to FIG. 3 , as the inner hole of the steel pipe 10 is deformed, the deformation sensor 112 will be deformed together as indicated by an exaggerated dotted line, and the voltage measurement value will change. The displacement of the voltage value is used to measure the displacement of the bore according to the Wheatstone Bridge principle.

Referring to FIGS. 1 to 5 , the electrical unit 113 supplies power to the strain sensor 112, receives a signal from it, and measures the displacement of the bore of the steel pipe 10 according to the Wheatstone Bridge principle. can

At this time, since the principle of the Wheatstone Bridge is a well-known principle, a detailed description thereof will be omitted here.

At this time, the electrical unit 113 may not only receive the voltage measurement signal value measured from each deformation sensor 112, but also supply and control power therefor.

At this time, the electrical part 113 may be installed and supported so as to be fixed to an inner part of the ring frame.

At this time, the electrical unit 113 may be connected to the strain sensor 112 or the communication unit 400 through the wire 114 .

Referring to FIG. 5 , the auxiliary fixing part 115 may fix the ring frame 111 so as not to deviate from the installation position of the steel pipe 10 .

At this time, the auxiliary fixing part 115 may be a ring-shaped fixing member fixed to the inner surface of the steel pipe 10 at a lower portion thereof to support the ring frame 111 .

At this time, by supporting the ring frame 111 from the bottom as a whole, the ring-shaped fixing member can prevent the ring frame 111 from moving downward or falling off due to its own weight.

At this time, since the ring-shaped fixing member is bonded and fixed to the inner wall surface of the steel pipe 10 with an adhesive, when the steel pipe 10 is deformed, it may be deformed along with it. Of course, since the inner diameter of the ring frame 111 is also custom-made and fixed to the inner wall surface of the steel pipe 10, eventually the steel pipe 10, the ring frame 111, and the ring-shaped fixing member that is the auxiliary fixing part 115 are all together. can be transformed

Referring to FIG. 1 , a wind power generator equipped with a ring-type displacement gauge 100 according to a first embodiment of the present invention is shown. Since the wing 2 and the generator are installed at the top of the steel pipe 10, its weight is considerable. The measuring device 100 is installed at the joint of the steel pipe 10. Four ring modules 110-140, each of which has two deformation sensors 112, are installed in four rows. At this time, in the four ring frames 110-140, the deformation sensor 112 is disposed in the north-south direction in the top and bottom ring modules 110 and 140, and in the east-west direction in the two ring modules 120 and 130 in the middle. A sensor 112 may be disposed. Power is supplied to the deformation sensors 112 from the electrical unit 113 , and voltage value signals measured by the deformation sensors 112 may be input to the electrical unit 113 .

Referring to FIG. 2, a state in which the steel pipe 10 is broken is shown. The steel pipe 10 may be broken due to various causes, and most of these phenomena appear prominently at the joint. By installing the measuring device 100 at the joint in this way, it can be detected before the steel pipe 10 is broken, and countermeasures can be taken to prevent the steel pipe 10 from breaking in advance.

Referring to FIGS. 3 and 4 , one ring module 110 is shown. The ring frame 111 may be manufactured to fit the inner diameter of the location to be installed. It can be manufactured in the form of a circular band, and the deformation sensors 112 are fixedly installed on the left and right sides therein. Therefore, when the steel pipe 10 is deformed, the deformation sensor 112 will also be deformed as indicated by the dotted line. This deformation changes the voltage value measured by the deformation sensors 112 installed in the four ring modules 110-140, and this value is compared with the original default value to change the amount of deformation of the steel pipe according to the Wheatstone Bridge principle. will measure

Referring to FIG. 5, a longitudinal section of the steel pipe 10 in which the ring module 110 is installed is shown. At the bottom of the ring frame 111, a ring-shaped fixing member that supports the ring frame 111 so that it does not go down is adhesively fixed to the inner wall surface of the steel pipe 10 as an auxiliary fixing part 115. Of course, the fixing member may be fixed in a physical or mechanical manner rather than adhesive.

Meanwhile, referring to FIG. 6 , the inside of the steel pipe to which the ring-type displacement gauge according to the second embodiment of the present invention is applied is shown. At this time, the auxiliary fixing part 215 may be a plurality of fixing members fixed at a predetermined angle to the inner surface of the steel pipe at the lower end of the ring frame 211 . At this time, the fixing member is attached at every 90 degrees here, but may be attached at every angle smaller than that. The fixing member may also be fixed to the inner wall surface of the steel pipe by adhesive or other physical or mechanical methods.

Meanwhile, referring to FIG. 7 , a plan view of a ring-type displacement gage according to a third embodiment of the present invention is shown. When installing the bore displacement measuring device inside the steel pipe, there is shown a case where there is a gap with the inner wall. Even if there is a gap, the ring module can maintain its original shape by installing correction members 112a and 113a capable of filling the gap therebetween. In this state, when deformation is applied to the steel pipe, the displacement of the bore can be measured by the deformation sensor. Although the correction members 112a and 113a may be manufactured in one thickness, it is of course possible to overlap a certain thickness.

On the other hand, as a fourth embodiment of the measuring device according to one aspect of the present invention, the development process of the 350mm ring-type displacement gauge is as follows.

First of all, the development goals and achievement levels are shown in Table 1 below.

For the design of the prototype, structural analysis was performed as shown in FIGS. 8 and 9 by performing structural analysis modeling on a previously manufactured ring-type displacement gauge with a diameter of 150 mm in order to design a ring-type displacement gauge with a diameter of 350 mm.

The reliability of the analysis method and results was secured by comparing and analyzing the results of structural analysis of a 150mm diameter ring-type displacement gauge with the test results of a previously manufactured prototype. In this way, after securing the reliability of the structural analysis method for the prototype design, the design for the 350mm diameter prototype was carried out.

As a result, for a diameter of 350 mm, prototypes as shown in FIGS. 10 and 11 were designed. In addition, since the thickness of the steel plate of the ring itself is closely related to the measurement range of the prototype, the final prototype was manufactured by reflecting the structural analysis results and determining the thickness of the ring-type displacement gauge with a diameter of 350mm as 1mm.

In order to achieve the goal of Table 1, the optimal specification suitable for a 350 mm diameter ring-type displacement gauge was determined through an iterative design process. 12 to 14 show design drawings of prototypes designed by analyzing the results of repetitive structural analysis, and using these results, a sensor steel prototype was manufactured by requesting a manufacturer specializing in machining. The body of FIG. 12 is assembled using the connection block of FIG. 13 and the cover of FIG. 14 . A plurality of fastening holes are formed in the connection block and the cover, respectively, and the main body is formed into a circular shape using these holes, and then connected to each other.

During the manufacturing process of the prototype, this prototype was manufactured while making various attempts until the ring type displacement gauge prototype was manufactured through repeated trial and error due to errors in material selection and processing.

As a result, five ring-type displacement gauge prototypes with a diameter of 350 mm and a range of measurement displacement of up to 50 mm were produced, two of which were used for outdoor structure experiments to determine the applicability of the structure, and three were commissioned to an authorized testing agency. The performance test of the prototype itself was conducted.

After manufacturing a prototype of a ring-type displacement gauge, the supplier assembled the prototype and attached a sensor (strain gauge) to complete the production of the prototype.

Regarding the performance test, in order to verify the performance of the initially planned ring-type displacement gauge prototype, it was divided into a performance test for the prototype itself and an experiment to verify the performance of the applicability of the structure by directly installing the ring-type displacement gauge on a circular steel pipe. .

The performance test for the prototype itself was conducted by delivering the prototype to an authorized testing agency. The applicability test for the structure of the prototype was conducted by the company that owns the equipment under the observation of an authorized testing agency.

15 is a photograph of a part corresponding to the lower part of a vertically erected pillar part, firmly fixed by hydraulic pressure using a fixing device.

16 is a photograph of a state in which a 350 mm diameter ring-type displacement gauge is installed inside the vicinity of a 400 mm diameter steel pipe connection. Since the portion occupied by the fixing part in the total 12m steel pipe column is 2m and the position of the end where the load acts is located about 1m inside from the end, the length of the test specimen can be said to be 9.0m. When a load in the horizontal direction is applied to a position of 9.0 m, in order to set a criterion for judging the accuracy of the amount of displacement measured by a ring-type displacement gauge installed inside the steel pipe, as shown in FIG. Install a displacement gauge.

Performance test results and test results show that the diameter of the ring-type displacement gage shows an error of less than 2% on average, and even in the measurement results according to the amount of displacement, the error at the maximum displacement of 50 mm is 1.7%, indicating an error of less than 2%.

In addition, as a result of measuring whether the ring type displacement gauge can be measured for various displacement variations and temperature measurement ranges, it was confirmed that the measurement was performed without any problems in all cases.

The test method is as follows.

After installing a ring-type displacement gauge with a diameter of 350 mm on the steel pipe, apply a load at a position 9.0 m from the fixed part of the steel pipe and increase it to about 20 kN.

19 shows the amount of displacement with time, and FIG. 20 shows the displacement results of the external displacement meter and the inner ring type displacement meter according to the applied load.

When the horizontal load is about 10 kN, the displacement of the external displacement gauge and the internal displacement gauge occurs by about 30 mm, and below this, the measured values of the external displacement gauge and the internal displacement gauge almost coincide.

When the horizontal load is applied more than 10 kN, the amount of displacement gradually increases, and the difference between the measured values of the external displacement gauge and the internal displacement gauge tends to increase gradually.

Considering that the inner diameter of a 400 mm diameter steel pipe is about 390 mm, the distance between both sides of the ring type displacement gauge is 40 mm, but the distance between one side is 20 mm. It is judged that sufficient displacement was not secured due to collision with (sponge).

In the future, it is judged that there is a need to conduct a structure experiment using a steel pipe with a diameter larger than that of the ring-type displacement gauge.

For reference, looking at the analysis result of FIG. 21 using a specialized structural analysis program, it appears to be almost similar to the measurement result of the straight-line displacement gauge installed outside the steel pipe connection. That is, when a horizontal load of 20 kN is applied, the experimental displacement generated at the steel pipe connection is about 70 mm, and it appears to be about 72 mm in the structural analysis.

Although the embodiments of the present invention have been described, the spirit of the present invention is not limited by the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention may add or change components within the scope of the same spirit. Other embodiments can be easily proposed by adding, deleting, adding, etc., but this will also be said to be within the scope of the present invention.

1: wind generator
2: wing 10: steel pipe
100: measuring device 110-140: ring module
111, 211, 311: ring frame 112, 312: strain sensor
113, 313: electrical part 114: wire
115, 215, 320: auxiliary fixing part

Claims (5)

A ring frame fixedly installed in a circular shape along the inner surface of the steel pipe;
Deformation sensors disposed on the ring frame individually or in pairs to face each other and installed in a circular shape along the wall surface of the steel pipe to detect a voltage according to deformation of the steel pipe;
an electrical unit supplying power to the deformation sensor and receiving a signal from the deformation sensor to measure displacement of the bore of the steel pipe; and
An auxiliary fixing part for fixing the ring frame so that it does not deviate from the installation position of the steel pipe; includes,
The auxiliary fixing part is a ring-shaped fixing member fixed to the inner surface of the steel pipe at the bottom thereof to support the ring frame. delete delete delete According to claim 1,
The auxiliary fixing part is fixed to the inner surface of the steel pipe by an adhesive, a ring-type displacement gauge.

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