Circular ring array ultrasonic sensor for detecting local stress distribution uniformity of flange sealing area

Abstract

A ring array ultrasonic sensor for detecting local stress distribution uniformity of a flange sealing area comprises n ultrasonic sensing units which are arranged in a ring array on the circumference of the ultrasonic sensor, the adjacent ultrasonic sensing units are bonded with each other, and n is an even number; the central area of the ultrasonic sensor is filled with an epoxy sound absorption material; the ultrasonic sensing unit comprises a 1 / n annular columnar wedge block, a 1 / n annular columnar piezoelectric array element and a 1 / n annular columnar backing block; the upper surface of the wedge block inclines outwards to the bottom, an inclination angle alpha is formed between the wedge block and the horizontal plane, and the lower surface of the wedge block is horizontal; and the wedge block, the piezoelectric array element and the backing block are sequentially and fixedly connected together from bottom to top.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic nondestructive testing, and particularly relates to a circular ring array ultrasonic sensor for detecting local stress distribution uniformity of a sealing area of a flange. BACKGROUND

[0002] As a key detachable structure in pressure-bearing equipment and pipeline systems, the sealing integrity of a flange connection is directly related to the safety and energy efficiency of modern industrial devices such as chemical industry, oil refining and power generation. Such connections are long-term served in harsh working conditions such as high temperature, high pressure, flammable and explosive, and once a leakage occurs, it is easy to cause major safety accidents and environmental accidents.

[0003] Practice shows that the sealing failure of a flange is not always due to insufficient total pre-tightening force, but more often due to local uneven stress distribution in the sealing area. Therefore, directly and accurately detecting the local stress distribution uniformity of the sealing area of the flange is the most direct way to predict the sealing failure of the flange and ensure safe operation. At present, the standard detection method for the stress uniformity of the flange in the industry is to first detect the pre-tightening force of the connecting bolt by using a traditional ultrasonic sensor, and then indirectly evaluate the sealing condition of the flange. The limitations of this technical path are: first, the direct detection object is the bolt rather than the sealing area, and the data obtained is the axial force of the bolt, which is indirect and easy to misjudge; second, in a traditional single piezoelectric array element sensor, the piezoelectric array element used to generate excitation ultrasonic waves and receive reflected ultrasonic waves is usually the same one, which can only provide stress information at discrete points, and cannot perform one-time scanning on a local area and detect the stress uniformity of the local area. Therefore, it is necessary to research an ultrasonic sensor that can directly detect the local stress uniformity of the sealing area of the flange. SUMMARY

[0004] Therefore, it is necessary to provide a circular ring array ultrasonic sensor for detecting local stress distribution uniformity of a sealing area of a flange, so as to realize direct detection of the local stress uniformity of the sealing area of the flange and improve the efficiency and precision of the detection of the sealing area of the flange.

[0005] A circular ring array ultrasonic sensor for detecting local stress distribution uniformity of a sealing area of a flange comprises: n ultrasonic sensing units arranged in a circular ring array around the circumference of the ultrasonic sensor, adjacent ultrasonic sensing units being bonded to each other, wherein n is an even number; the central area of the ultrasonic sensor is filled with epoxy sound-absorbing material; the ultrasonic sensing unit comprises: a 1 / n ring column-shaped wedge, a 1 / n ring column-shaped piezoelectric array element and a 1 / n ring column-shaped backing block; the upper surface of the wedge outwardly presents a bottom-tilting shape and forms an inclination angle a with the horizontal plane, and the lower surface of the wedge presents a horizontal shape; the wedge, the piezoelectric array element and the backing block are fixedly connected together from bottom to top.

[0006] Preferably, 4≤n≤16.

[0007] Preferably, the adjacent ultrasonic sensing units are bonded to each other by double-sided tape.

[0008] Preferably, the double-sided tape is polyurethane foam double-sided tape.

[0009] Preferably, the epoxy sound-absorbing material is filled in the central gap formed by the surrounding of all the ultrasonic sensing units.

[0010] Preferably, the lower surface of the piezoelectric array element and the upper surface of the wedge are bonded together by epoxy resin; and the backing block is poured above the piezoelectric array element.

[0011] Preferably, the ultrasonic sensing unit further comprises a positive electrode lead and a negative electrode lead; one end of the positive electrode lead is welded to the upper surface of the piezoelectric array element, and the other end is led out to the periphery of the ultrasonic sensing unit; one end of the negative electrode lead is welded to the lower surface of the piezoelectric array element, and the other end is led out to the periphery of the ultrasonic sensing unit.

[0012] Preferably, the end radius of the cross section of the backing block is the same as the end radius of the cross section of the piezoelectric array element, and the inner side and the outer side of the backing block are aligned with the inner side and the outer side of the piezoelectric array element, respectively; the end radius of the cross section of the wedge is greater than the end radius of the cross section of the piezoelectric array element, and the outer side of the wedge is aligned with the outer side of the piezoelectric array element.

[0013] Preferably, the relationship between the inclination angle α and the thickness h of the single flange plate of the detected flange is shown in formula group (1), wherein, is the refraction angle of the ultrasonic wave in the flange, D is the distance from the center point of the piezoelectric array element to the center axis of the ultrasonic sensor, h is the thickness of the single flange plate of the detected flange, is the refractive index of the wedge, is the refractive index of the detected flange; Formula group (1)

[0014] Preferably, one end of the positive electrode lead is welded to the upper surface of the piezoelectric array element near the outer edge, and the other end is led out to the periphery of the ultrasonic sensing unit; one end of the negative electrode lead is welded to the lower surface of the piezoelectric array element near the outer edge, and the other end is led out to the periphery of the ultrasonic sensing unit.

[0015] The annular array ultrasonic sensor for detecting the local stress distribution uniformity of the flange sealing area, by arranging n ultrasonic sensing units in a circular array on the circumference, and by setting the upper surface of the wedge of the ultrasonic sensing unit to be outwardly inclined to the bottom, provides an incident angle for the ultrasonic wave excited by the piezoelectric element above the wedge; so that during detection, the ultrasonic sensing units in opposite directions can be used for exciting ultrasonic wave and receiving ultrasonic wave respectively, and by sequentially applying signals to the ultrasonic sensing units, the detection of the flange sealing area in 8 directional dimensions is realized, and then by comparing and analyzing the signals in 8 directional dimensions, the stress uniformity distribution of the detected area is directly obtained; compared with the prior art, the present application realizes the direct detection of the local stress uniformity of the flange sealing area, and improves the efficiency and accuracy of the flange sealing area detection. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a first partial cross-sectional perspective structure schematic diagram of the ultrasonic sensor in the present application.

[0017] Figure 2 It is a perspective structure schematic diagram of the ultrasonic sensing unit in the present application.

[0018] Figure 3 It is a side view of the ultrasonic sensing unit in the present application.

[0019] Figure 4 It is a schematic diagram of the propagation path of the sound wave when the flange is detected by using the ultrasonic sensor.

[0020] In the figure: ultrasonic sensor 1; ultrasonic sensing unit 10; wedge 100; piezoelectric element 101; positive lead 1010; negative lead 1011; backing block 102; epoxy sound-absorbing material 11; flange plate 20; gasket 21; excited ultrasonic wave 30; reflected ultrasonic wave 31; ultrasonic sensor center axis 4. DETAILED DESCRIPTION

[0021] The technical solutions and technical effects of the embodiments of the present application are further described in detail in combination with the drawings of the present application.

[0022] Please refer to Figure 1 , 2And 3, a circular array ultrasonic sensor 1 for detecting the stress distribution uniformity of the local sealing area of a flange, comprising: 8 ultrasonic sensing units 10 arranged in a circular array on the circumference of the ultrasonic sensor 1, and adjacent ultrasonic sensing units 10 are bonded to each other; the central region of the ultrasonic sensor 1 is filled with epoxy sound-absorbing material 11; the ultrasonic sensing unit 10 comprises: a 1 / 8 ring column-shaped wedge 100, a 1 / 8 ring column-shaped piezoelectric element 101, and a 1 / 8 ring column-shaped backing block 102; the upper surface of the wedge 100 is outwardly inclined to the bottom, forming an angle α with the horizontal plane, and the lower surface of the wedge 100 is horizontal; the wedge 100, the piezoelectric element 101, and the backing block 102 are sequentially and fixedly connected together from bottom to top.

[0023] In the present application, the number of ultrasonic sensing units 10 is 4-16, because if more than 16, the area of the piezoelectric element 101 of each ultrasonic sensing unit 10 is too small, the energy of the generated excitation ultrasonic wave 30 is insufficient, and the detection accuracy is too low, and if less than 4, the detection dimension of the local area is too small, and the detection is meaningless. In the present embodiment, the number of ultrasonic sensing units 10 is set to 8.

[0024] In the present embodiment, the 8 ultrasonic sensing units 10 are the same in structure and size, and are arranged in a circular array on the circumference of the ultrasonic sensor 1 and are symmetrical to each other; the wedge 100 is provided to provide an incident angle for the ultrasonic wave excited by the piezoelectric element 101, specifically: by setting the upper surface of the wedge 100 to be outwardly inclined to the bottom, the piezoelectric element 101 above the wedge 100 can also be inclined, when the piezoelectric element 101 of one of the ultrasonic sensing units 10 is excited by an electric signal, it can emit an excitation ultrasonic wave 30 signal perpendicular to the direction of the surface of the piezoelectric element 101, i.e. the upper surface of the wedge 100, the emitted excitation ultrasonic wave 30 signal enters the flange plate 20 of the detected flange at an inclined angle, then is reflected back into the flange plate 20 when encountering the gasket 21, and finally is received by the piezoelectric element 101 of the ultrasonic sensing unit 10 in the opposite direction which is also inclined; therefore, when detecting the flange, one ultrasonic sensing unit 10 excites ultrasonic waves, and the ultrasonic sensing unit 10 in the opposite direction receives ultrasonic waves, and the 8 ultrasonic sensing units sequentially excite and receive ultrasonic waves, which can realize the detection of the stress in 8 directions of the local sealing area of the flange, and obtain the stress distribution uniformity in the 8 directions, compared with the prior art, the detection efficiency and accuracy of the stress distribution uniformity of the local sealing area of the flange are effectively improved.

[0025] Meanwhile, in the embodiment, the epoxy sound absorption material 11 is filled in the central region of the ultrasonic sensor 1, which on one hand ensures the integrity and stability of the ultrasonic sensor 1, and on the other hand reduces the interference of stray sound waves between the ultrasonic sensor unit 10 arrays, and improves the detection accuracy; the backing block 102 is used to absorb the excess sound wave vibration, reduce the ringing effect of the piezoelectric array element, and improve the detection accuracy.

[0026] Further, in order to isolate the sound field interference between the connected ultrasonic sensor units 10 and improve the detection accuracy, the double-sided adhesive is used to bond the adjacent ultrasonic sensor units 10 to each other, and the double-sided adhesive can be polyurethane foam double-sided adhesive.

[0027] Further, in order to ensure the integrity and stability of the ultrasonic sensor 1 and reduce the stray sound wave crosstalk between the ultrasonic sensor unit 10 arrays, and improve the detection accuracy, the epoxy sound absorption material 11 is filled in the central gap formed by all the ultrasonic sensor units 10. The central region of the ultrasonic sensor 1 is cylindrical in shape, and the region opposite to the wedge block 100 is a circular truncated cone shape, and the region opposite to the piezoelectric array element 101 and the backing block 102 is a circular truncated cone shape with a large upper part and a small lower part.

[0028] Further, in order to make the sound field of the piezoelectric array element 101 better propagate into the wedge block 100, and then propagate into the detected flange, and improve the detection accuracy, the lower surface of the piezoelectric array element 101 and the upper surface of the wedge block 100 are bonded together by epoxy resin; the backing block 102 is poured above the piezoelectric array element 101.

[0029] Further, please refer to Figure 1 and 2 , the ultrasonic sensor unit 10 further comprises: a positive electrode lead 1010 and a negative electrode lead 1011; one end of the positive electrode lead 1010 is welded to the upper surface of the piezoelectric array element 101, and the other end is led out to the periphery of the ultrasonic sensor unit 10; one end of the negative electrode lead 1011 is welded to the lower surface of the piezoelectric array element 101, and the other end is led out to the periphery of the ultrasonic sensor unit 10.

[0030] In the embodiment, by arranging the positive electrode lead 1010 and the negative electrode lead 1011, an electric signal can be applied to the piezoelectric array element 1010 for excitation, or an electric signal can be received from the piezoelectric array element 1011 during detection.

[0031] Further, please refer to Figure 1 , 2And 3, in order to reduce the difficulty of ultrasonic sensor 1 manufacturing, improve the safety of manufacturing and the stability of ultrasonic sensor 1, the end radius of the cross section of the backing block 102 is the same as the end radius of the cross section of the piezoelectric element 101, and the inner side and the outer side of the backing block 102 are aligned with the inner side and the outer side of the piezoelectric element 101 respectively; the end radius of the cross section of the wedge block 100 is greater than the end radius of the cross section of the piezoelectric element 101, and the outer side of the wedge block 100 is aligned with the outer side of the piezoelectric element 101.

[0032] In the embodiment, since the piezoelectric element 101 is brittle and fragile, if the inner end, i.e. the end close to the center of the ultrasonic sensing unit 10, is too sharp, it is easy to be broken when bonding with the wedge block 100, and the manufacturing difficulty is large, therefore, through the above setting, the piezoelectric element 101 is smaller than the wedge block 100, and the piezoelectric element 101 does not completely cover the wedge block, thereby reducing the difficulty of manufacturing.

[0033] Further, please refer to Figure 4 , in order to make the ultrasonic sensor 1 better match the detected flange and improve the detection accuracy, the relationship between the inclination angle α and the thickness h of the single flange plate 20 of the detected flange is shown in formula set (1), wherein, is the refraction angle of ultrasonic wave in the flange, D is the distance from the center point of the piezoelectric element 101 to the center axis 4 of the ultrasonic sensor, h is the thickness of the single flange plate 20 of the detected flange, is the refractive index of the wedge block 100, is the refractive index of the detected flange; Formula set (1)

[0034] In the embodiment, through the above setting, during detection, the piezoelectric element 101 of the ultrasonic sensing unit 10 in the opposite direction can be directly opposite, and the sound field signal and energy excited by the piezoelectric element 101 in the excitation side can be maximally received by the piezoelectric element 101 in the receiving side, thereby improving the detection accuracy.

[0035] Further, please refer to Figure 1 、 2 And 3, in order to improve the convenience of manufacturing and improve the flatness of the bonding between the piezoelectric element 101 and the wedge block 100 and the backing block 102, one end of the positive lead 1010 is welded and connected with the upper surface of the piezoelectric element 101 close to the outer edge, and the other end is led out to the periphery of the ultrasonic sensing unit 10; one end of the negative lead 1011 is welded and connected with the lower surface of the piezoelectric element 101 close to the outer edge, and the other end is led out to the periphery of the ultrasonic sensing unit 10.

[0036] The working process and principle of the present application are as follows:

[0037] Please refer toFigure 4 In the detection, the ultrasonic sensor 1 is placed on the surface of the flange to be detected, and the excitation signals are sequentially applied to the eight ultrasonic sensing units 10;

[0038] When an ultrasonic sensing unit 10 is applied with an excitation signal, the piezoelectric array element 101 thereof is excited to emit an excitation ultrasonic wave 30 signal, which is incident into the flange plate 20 at an oblique angle α, propagates in the flange plate 20 at a refraction angle β after refraction, is reflected back into the flange plate 20 after encountering the gasket 21, and is finally received by the piezoelectric array element 101 of the ultrasonic sensing unit 10 in the opposite direction;

[0039] By sequentially applying the excitation signals to the eight ultrasonic sensing units 10 while the ultrasonic sensing units 10 in the opposite direction receive the signals, the detection area is detected in eight direction dimensions.

[0040] By comparing and analyzing the signals in the eight direction dimensions, the stress uniformity distribution of the detected area is directly obtained.

[0041] The above-mentioned annular array ultrasonic sensor for detecting the local stress distribution uniformity of the flange sealing area arranges eight ultrasonic sensing units 10 in a circular array around the circumference, and sets the upper surface of the wedge 100 of the ultrasonic sensing unit 10 to be outwardly inclined to the bottom, thereby providing an incident oblique angle for the ultrasonic wave excited by the piezoelectric array element 101 above the wedge 100. During the detection, the ultrasonic sensing units 10 in the opposite direction can be used to generate an excitation ultrasonic wave 30 and receive a reflected ultrasonic wave 31, respectively. By sequentially applying the signals to the ultrasonic sensing units 10, the flange sealing area to be detected is detected in eight direction dimensions. By comparing and analyzing the signals in the eight direction dimensions, the stress uniformity distribution of the detected area is directly obtained. Compared with the prior art, the present application directly detects the local stress uniformity of the flange sealing area, and improves the efficiency and accuracy of the flange sealing area detection.

[0042] The above-mentioned only the preferred embodiments of the present application, of course, can not be limited to the scope of the present application, those skilled in the art can understand the implementation of the above-mentioned all or part of the process, and the equivalent changes made by the present application claims, still belong to the scope of the present application.

Claims

1. A circular array ultrasonic sensor for detecting local stress distribution uniformity in a flange seal area, characterized by, The application relates to an ultrasonic sensor, which comprises the following: The ultrasonic sensor is arranged in a circular array, and adjacent ultrasonic sensor units are bonded to each other, wherein n is an even number; the central region of the ultrasonic sensor is filled with epoxy sound-absorbing material; the ultrasonic sensor unit comprises a 1 / n ring column-shaped wedge, a 1 / n ring column-shaped piezoelectric element and a 1 / n ring column-shaped backing block; the upper surface of the wedge is outwardly inclined to the bottom and forms an angle alpha with the horizontal plane, and the lower surface of the wedge is horizontal; the wedge, the piezoelectric element and the backing block are sequentially fixed and connected together from the bottom to the top.

2. The circular array ultrasonic sensor for flange seal area local stress distribution uniformity inspection of claim 1, wherein: 4≤n≤16。 3. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasket sealing area of claim 1, wherein: The adjacent ultrasonic sensor units are bonded to each other through double-sided adhesive tape.

4. The circular array ultrasonic transducer for flange seal area local stress distribution uniformity inspection of claim 3, wherein: The double-sided adhesive tape is polyurethane foam double-sided adhesive tape.

5. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasket sealing area of claim 1, wherein: The epoxy sound-absorbing material is filled in the central gap formed by all the ultrasonic sensor units.

6. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasket sealing area of claim 1, wherein: The lower surface of the piezoelectric element and the upper surface of the wedge are bonded together through epoxy resin; and the backing block is poured above the piezoelectric element.

7. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasket sealing area of claim 1, wherein, The ultrasonic sensor unit further comprises a positive electrode lead and a negative electrode lead; one end of the positive electrode lead is welded to the upper surface of the piezoelectric element, and the other end is led out to the periphery of the ultrasonic sensor unit; one end of the negative electrode lead is welded to the lower surface of the piezoelectric element, and the other end is led out to the periphery of the ultrasonic sensor unit.

8. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasketed area of a flange as claimed in claim 1, wherein: The end radius of the cross section of the backing block is the same as the end radius of the cross section of the piezoelectric element, and the inner side and the outer side of the backing block are respectively aligned with the inner side and the outer side of the piezoelectric element; the end radius of the cross section of the wedge is greater than the end radius of the cross section of the piezoelectric element, and the outer side of the wedge is aligned with the outer side of the piezoelectric element.

9. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasketed flange region of claim 1, wherein: The relationship between the inclination angle α and the thickness h of a single flange plate of the flange under detection is shown in formula set (1), wherein, is the refraction angle of the ultrasonic wave in the flange, D is the distance from the center point of the piezoelectric element to the center axis of the ultrasonic sensor, h is the thickness of a single flange plate of the flange under detection, is the refractive index of the wedge, is the refractive index of the flange under detection; Formula group (1).

10. The circular array ultrasonic transducer for local stress distribution uniformity inspection of a gasketed flange region of claim 7, wherein: One end of the positive electrode lead is welded to the outer edge of the upper surface of the piezoelectric element, and the other end is led out to the periphery of the ultrasonic sensor unit; one end of the negative electrode lead is welded to the outer edge of the lower surface of the piezoelectric element, and the other end is led out to the periphery of the ultrasonic sensor unit.

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