Bent pipe pressure balance type expansion joint transmission mechanical impedance testing device and method

Abstract

The invention discloses a bent pipe pressure balance type expansion joint transmission mechanical impedance testing device which comprises an adjustable frame, a limiting unit and an output mechanism. The limiting unit is arranged on the adjustable frame and comprises an elastic mechanism and a limiting mechanism; one end of the elastic mechanism is connected with the adjustable frame, the other end of the elastic mechanism is connected with one end of the limiting mechanism, and the other end of the limiting mechanism is hermetically connected with the input end of the elbow pressure balance type expansion joint; an axial excitation point, a radial excitation point and an acceleration sensor are arranged on the limiting mechanism; the output mechanism comprises a bottom sealing adapter plate, a three-way force plate and a force plate lower adapter plate which are sequentially arranged from top to bottom, and the bottom sealing adapter plate is connected with the output end of the bent pipe pressure balance type expansion joint. The invention further discloses a bending pressure balance type expansion joint transmission mechanical impedance testing method. According to the invention, vibration in an unexpected direction during transmission of a mechanical impedance test can be avoided, so that the whole device is more stable, and the accuracy of a test result is ensured.

Description

Technical Field

[0001] The invention relates to the field of impedance performance testing of vibration isolators at low frequencies, and in particular to a device and method for testing the mechanical impedance transmitted by an elbow pressure-balanced expansion joint. Background Art

[0002] The elbow pressure-balanced expansion joint is an expansion joint used to absorb the combined axial and lateral displacements and balance the pressure thrust of the bellows. It is used for vibration isolation of mechanical equipment. The direct method of transferring mechanical impedance test is a test method used to evaluate the mechanical impedance transfer characteristics between different components in a mechanical system. With the increasing emphasis on vibration isolation of mechanical equipment, people are paying more and more attention to the impedance performance of vibration isolators at low frequencies. Therefore, the elbow pressure-balanced expansion joint usually needs to be tested for transfer mechanical impedance before use. However, the existing transfer mechanical impedance test of the elbow pressure-balanced expansion joint mostly refers to the standard dynamic stiffness test, which is prone to vibration in undesired directions and instability during the test, and the test results are inaccurate. Summary of the invention

[0003] The main purpose of the present invention is to provide a device and method for testing the mechanical impedance transmitted by a bent pipe pressure balanced expansion joint, which can avoid vibration in an undesired direction during the mechanical impedance transmission test, making the entire device more stable to ensure the accuracy of the test results.

[0004] The technical solution adopted by the present invention is:

[0005] A device for testing the mechanical impedance transmitted by a bent pipe pressure-balanced expansion joint, comprising an adjustable frame, a limit unit, and an output mechanism;

[0006] The adjustable frame can be adjusted along with the height of the elbow pressure balance expansion joint;

[0007] The limit unit is installed on the adjustable frame, and includes an elastic mechanism and a limit mechanism; one end of the elastic mechanism is connected to the adjustable frame, and the other end is connected to one end of the limit mechanism, and the other end of the limit mechanism is sealed and connected to the input end of the elbow pressure balance expansion joint; the limit mechanism is provided with an axial excitation point, a radial excitation point, and an acceleration sensor;

[0008] The output mechanism includes a bottom sealing adapter plate, a three-way force plate, and a force plate lower adapter plate which are arranged in sequence from top to bottom. The bottom sealing adapter plate is connected to the output end of the elbow pressure balanced expansion joint; the bottom sealing adapter plate is responsible for sealing the output end flange of the elbow pressure balanced expansion joint.

[0009] According to the above scheme, the limit mechanism includes a limit sealing plate, a limit connecting rib plate, and a limit frame connected in sequence; the limit sealing plate is sealed and connected to the input end of the elbow pressure balance type expansion joint, there are multiple acceleration sensors arranged along the circumference of the limit sealing plate, the axial excitation point is set at the center of the limit sealing plate, and the radial excitation point is set at the center of the side of the limit sealing plate; there are multiple limit connecting rib plates, and there is a gap between adjacent limit connecting rib plates, and the gap is used for input excitation of the excitation rod of the vibrator; the four sides of the limit frame are connected to the elastic mechanism by bolts to ensure that the elbow pressure balance type expansion joint does not lose stability during the test, and the center of the limit frame is opened for the vibrator to probe into. The limit sealing plate is responsible for sealing the flange at the input end of the elbow pressure balance type expansion joint.

[0010] According to the above scheme, the limit sealing plate is provided with a water injection hole and an exhaust hole, and a pump is used to inject water into the elbow pressure balance expansion joint through the water injection hole to pressurize it to the required pressure, and then the water injection hole and the exhaust hole are sealed, which is very convenient to use.

[0011] According to the above scheme, there are four elastic mechanisms, which are arranged on the adjustable frame, including an outer airbag seat, an elastic airbag, and an inner airbag seat; one end of the outer airbag seat is connected to the adjustable frame, and the other end is connected to one end of the elastic airbag, and the other end of the elastic airbag is connected to the inner airbag seat, and the inner airbag seat is connected to the limit frame of the limit mechanism through bolts. By adjusting the working length of the elastic airbag, the elbow pressure balance type expansion joint can maintain its original state before the experiment, which can avoid the elbow pressure balance type expansion joint from becoming unstable during the test pressure process, and decouple the limit mechanism.

[0012] According to the above scheme, the adjustable frame is a door frame with adjustable size and height, which is fixed on the foundation through a base; the door frame is connected to the elastic mechanism through through holes and bolts.

[0013] According to the above scheme, the bottom sealing adapter plate includes a bottom sealing plate, a bottom connecting rib plate, and a bottom adapter plate connected in sequence; the bottom sealing plate is sealed and connected to the output end of the elbow pressure balance expansion joint, and the bottom adapter plate is bolted to the three-way force plate, so that the output end blocks the dynamic force from being transmitted to the three-way force plate during the test. A large number of rib plates are welded on the bottom adapter plate, and the bottom is transferred to the upper surface of the three-way force plate through a large number of bolts. The bottom sealing adapter plate can not only seal the output end of the elbow pressure balance expansion joint well, but also transmit the force to the three-way force plate well, ensuring the accuracy of the test results.

[0014] According to the above scheme, the three-way force plate is built with a dynamic force sensor for measuring the blocking dynamic force at the output end of the elbow pressure balance expansion joint, so as to accurately obtain the time domain signal of the dynamic force at the output end.

[0015] According to the above scheme, the lower adapter plate of the force plate is connected to the lower part of the three-way force plate by bolts and is fastened to the foundation by large bolts.

[0016] According to the requirements of relevant standards, taking the measurement of the displacement impedance of the vibration isolator as an example, when at low frequency (generally 10-300Hz), the impedance of the elbow pressure balance expansion joint is measured by the direct method. The direct method obtains the displacement mechanical impedance of the expansion joint at the corresponding frequency by measuring the blocking force at the blocking end and the displacement at the input end, that is, at this time, the output module uses the force plate to measure the blocking force at the blocking end.

[0017] Before the test, the exciter excitation rod is extended to the excitation hole (axial excitation point) drilled in the center of the limit sealing plate through the gap left by the oblique long rib plate (limit connection rib plate) welded on the limit frame for excitation input, and the acceleration sensor is arranged on the limit sealing plate. The output flange of the elbow pressure balance expansion joint is sealed and connected to the bottom sealing plate, and the three-way force plate measures the dynamic blocking force in real time.

[0018] The present invention also provides a method for testing the mechanical impedance transmitted by a bend-pipe pressure-balanced expansion joint, and the method adopts the above-mentioned device for testing the mechanical impedance transmitted by a bend-pipe pressure-balanced expansion joint.

[0019] According to the above scheme, by adjusting the elastic airbag pressure of the elastic mechanism, the elbow pressure balance type expansion joint reaches the initial state;

[0020] The time domain signals of the dynamic force at the output end measured by the dynamic force sensors at the output end of the elbow pressure balanced expansion joint are added and then converted into signals in the frequency domain by Fourier transform; the time domain signals of the acceleration measured by the acceleration sensor at the input end of the elbow pressure balanced expansion joint are averaged and then converted into signals in the frequency domain by Fourier transform; the output end force in the frequency domain is divided by the corresponding acceleration in the frequency domain, and the result is mass corrected to obtain the transmission acceleration impedance of the elbow pressure balanced expansion joint.

[0021] The beneficial effects produced by the present invention are:

[0022] The working length of the elastic mechanism is adjusted by the limit mechanism to keep the elbow pressure balance expansion joint in its original state before the test, so as to avoid the elbow pressure balance expansion joint from becoming unstable during the test and ensure the accuracy of the test results;

[0023] By setting up an elastic mechanism to decouple the limit mechanism, additional influence on the test results can be avoided and the accuracy of the test results can be ensured;

[0024] By setting up an elastic mechanism, vibration in an undesired direction during the mechanical impedance test can be avoided; by setting up a limit mechanism and an output mechanism, the entire device is made more stable, ensuring the accuracy of the test results;

[0025] The present invention utilizes the direct method to measure the impedance principle, and sets an adjustable frame that can adjust the height, a limit mechanism that allows the vibration rod of the vibrator to penetrate into the space, and an elastic mechanism that can decouple the additional mass while ensuring the stable conduct of the pressure and test, thereby ensuring the accuracy of the test results;

[0026] The structure is easy to assemble and disassemble, has good versatility and a wide range of applications.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a positive triaxial measurement of the test device for the mechanical impedance transmitted by the elbow pressure balance expansion joint;

[0030] Figure 2 It is a front view structural schematic diagram of a test device for transmitting mechanical impedance of a bend pressure balance expansion joint;

[0031] Figure 3 It is a side view structural diagram of a test device for transmitting mechanical impedance of a bend pressure-balanced expansion joint;

[0032] Figure 4 1 is a schematic diagram of the top view of the limiting mechanism;

[0033] Figure 5 1 is a schematic diagram of the structure of the limit sealing plate;

[0034] Figure 6 It is a structural diagram of the limit frame;

[0035] Figure 7 It is a front view structural diagram of the limit mechanism;

[0036] Figure 8 1 is a front view structural diagram of the bottom sealing adapter plate;

[0037] Fig. 9 1 is a schematic diagram of the top view of the bottom sealing adapter plate;

[0038] Fig.10 It is a connection diagram of the bottom connecting rib plate and the bottom adapter plate;

[0039] In the figure: 1. adjustable frame, 2. outer airbag seat, 3. inner airbag seat, 4. elastic airbag, 5. base, 6. limiting mechanism, 6-1. limiting frame, 6-2. limiting connecting rib plate, 6-3. limiting sealing plate, 7. elbow pressure balance expansion joint, 8. bottom sealing adapter plate, 8-1. bottom sealing plate, 8-2. bottom connecting rib plate, 8-3. bottom adapter plate, 9. three-way force plate, 10. adapter plate under the force plate, 11. foundation, 12. acceleration sensor, 13. axial excitation point, 14. radial excitation point. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0042] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0043] In addition, it should be noted that the features of the various embodiments of the present invention may be combined or combined in part or in whole, and may interact and operate in different ways as will be appreciated by those skilled in the art. Each embodiment may be implemented independently of one another, or in an associated relationship.

[0044] Example 1

[0045] A device for testing the mechanical impedance transmitted by a bend pressure-balanced expansion joint, comprising an adjustable frame 1, a limiting unit, and an output mechanism. The adjustable frame 1 can be adjusted along with the height of the bend pressure-balanced expansion joint 7. In the present embodiment, the adjustable frame 1 is a gantry with adjustable size and height, located at the input end of the test device, constructed by a laboratory standard beam, and provided with through holes, and the size and height of the bend pressure-balanced expansion joint 7 can be adjusted. The adjustable frame 1 is connected to the elastic mechanism of the limiting unit through through holes and bolts. The adjustable frame 1 is bolted to the base 5 below and fixed to the foundation 11. The base 5 is located below the adjustable frame 1, and the adjustable frame 1 is fixed to make the test device stable and reliable. The limiting unit is mounted on the adjustable frame 1, and comprises an elastic mechanism and a limiting mechanism. One end of the elastic mechanism is bolted to the adjustable frame 1, and the other end is bolted to one end of the limiting mechanism. The other end of the limiting mechanism is sealed and connected to the input end of the bend pressure-balanced expansion joint 7. The limiting mechanism is provided with an axial excitation point 13, a radial excitation point 14, and an acceleration sensor 12. The output mechanism includes a bottom sealing adapter plate 8, a three-way force plate 9, and a force plate lower adapter plate 10, which are arranged in sequence from top to bottom. The bottom sealing adapter plate 8 is located between the elbow pressure balanced expansion joint 7 and the three-way force plate 9, and is used to seal the output end flange of the elbow pressure balanced expansion joint 7. It specifically includes three parts: a bottom sealing plate 8-1, a bottom connecting rib plate 8-2, and a bottom adapter plate 8-3. The bottom sealing plate 8-1 is sealed and connected to the output end of the elbow pressure balanced expansion joint 7. The bottom connecting rib plate 8-2 connects the bottom sealing plate 8-1 to the bottom adapter plate 8-3 by welding. The bottom adapter plate 8-3 is bolted to the three-way force plate 9, so that the output end blocking dynamic force is transmitted to the three-way force plate 9 and recorded during the test. In this embodiment, the three-way force plate 9 is located below the bottom sealing adapter plate 8, and has a built-in dynamic force sensor, which can accurately measure the output end blocking dynamic force of the elbow pressure balanced expansion joint 7. The lower adapter plate 10 of the force plate is located between the three-way force plate 9 and the foundation 11 (bolted to the lower part of the three-way force plate 9 and fixed on the foundation 11), ensuring the static state of the output end of the elbow pressure balance expansion joint 7. The foundation 11 is located below the entire device and is the basis for the test to ensure the stability of the device.

[0046] Example 2

[0047] Different from Example 1, the limiting mechanism 6 includes a limiting sealing plate 6-3, a limiting connecting rib plate 6-2, and a limiting frame 6-1 which are connected in sequence. The limiting sealing plate 6-3 is sealed and connected to the input end of the elbow pressure balance type expansion joint 7. A water injection hole and an exhaust hole are provided on the limiting sealing plate 6-3. Before testing, a pump is used to inject water into the elbow pressure balance type expansion joint 7 through the water injection hole to pressurize it to the required pressure, and then the water injection hole and the exhaust hole are sealed. There are multiple acceleration sensors 12 on the limiting sealing plate 6-3, which are arranged along the circumference of the limiting sealing plate 6-3. The axial excitation point 13 is set at the center of the limiting sealing plate 6-3, and the radial excitation point 14 is set at the center position of the side of the limiting sealing plate 6-3. There are multiple limiting connecting rib plates 6-2, and there is a gap between adjacent limiting connecting rib plates 6-2, and the gap is used for input excitation of the exciter excitation rod. The limiting frame 6-1 is a square frame with welded ribs inside for reinforcement. The center of the limit frame 6-1 is provided with a hole for the exciter to penetrate and perform axial excitation. In this embodiment, the four sides of the limit frame 6-1 are connected to the elastic mechanism by bolts to ensure that the elbow pressure balance expansion joint 7 does not lose stability during the test.

[0048] Example 3

[0049] The difference from Example 2 is that there are four elastic mechanisms, which are arranged on the adjustable frame 1, and include an outer airbag seat 2, an elastic airbag 4 (rubber elastic airbag), and an inner airbag seat 3. The outer airbag seat 2 and the inner airbag seat 3 are both similar to I-beam structures, respectively located between the elastic airbags 4, and are used to connect the elastic airbags 4 to the test system. Specifically: the opening at one end of the outer airbag seat 2 is connected to the through hole of the adjustable frame 1 through a bolt, and the opening at the other end is connected to one end of the elastic airbag 4 through a bolt, and the other end of the elastic airbag 4 is connected to the opening on one side of the inner airbag seat 3 through a bolt; the opening on the other side of the inner airbag seat 3 is connected to the limit frame 6-1 of the limit mechanism through a bolt. This embodiment adjusts the working length of the elastic airbag 4 to keep the elbow pressure balance type expansion joint 7 in its original state before the test, which can prevent the elbow pressure balance type expansion joint 7 from becoming unstable during the test pressure process, and decouples the limit mechanism 6 to ensure that the device does not become unstable during the test while ensuring that it does not have too much impact on the experimental results.

[0050] In this embodiment, the specific size of the elastic mechanism can be changed according to the size of the elbow pressure balance expansion joint and in combination with the adjustable frame 1.

[0051] Example 4

[0052] A method for testing the mechanical impedance of a pipe bending pressure-balanced expansion joint, the method adopts the testing device for the mechanical impedance of a pipe bending pressure-balanced expansion joint in Example 3. Before the test, the pressure of the elastic airbag 4 of the elastic mechanism is adjusted to make the pipe bending pressure-balanced expansion joint 7 reach an initial state.

[0053] The time domain signals of the dynamic force at the output end measured by the dynamic force sensors at the output end of the elbow pressure balanced expansion joint are added and then converted into signals in the frequency domain by Fourier transform; the time domain signals of the acceleration measured by the acceleration sensor at the input end of the elbow pressure balanced expansion joint are averaged and then converted into signals in the frequency domain by Fourier transform; the output end force in the frequency domain is divided by the corresponding acceleration in the frequency domain, and the result is mass corrected to obtain the transmission acceleration impedance of the elbow pressure balanced expansion joint.

[0054] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A device for testing the mechanical impedance transmitted by a pressure-balanced expansion joint of a bent pipe, characterized in that: It includes an adjustable frame, a limit unit, and an output mechanism; The limit unit is installed on the adjustable frame, and includes an elastic mechanism and a limit mechanism; one end of the elastic mechanism is connected to the adjustable frame, and the other end is connected to one end of the limit mechanism, and the other end of the limit mechanism is sealed and connected to the input end of the elbow pressure balance expansion joint; the limit mechanism is provided with an axial excitation point, a radial excitation point, and an acceleration sensor; The output mechanism comprises a bottom sealing adapter plate, a three-way force plate, and a force plate lower adapter plate which are arranged in sequence from top to bottom, and the bottom sealing adapter plate is connected to the output end of the elbow pressure balance expansion joint.

2. The device for testing the mechanical impedance transmitted by a pressure-balanced expansion joint of a bent pipe according to claim 1, characterized in that: The limiting mechanism includes a limiting sealing plate, a limiting connecting rib plate, and a limiting frame which are connected in sequence; the limiting sealing plate is sealed and connected to the input end of the elbow pressure balance type expansion joint, there are multiple acceleration sensors which are arranged along the circumference of the limiting sealing plate, the axial excitation point is set at the center of the limiting sealing plate, and the radial excitation point is set at the center position of the side of the limiting sealing plate; there are multiple limiting connecting rib plates, and there is a gap between adjacent limiting connecting rib plates, and the gap is used for input excitation of the excitation rod of the exciter; the four sides of the limiting frame are connected to the elastic mechanism, and the center of the limiting frame is opened for the exciter to probe into.

3. The device for testing the mechanical impedance transmitted by a bend pressure-balanced expansion joint according to claim 2, characterized in that: The limit sealing plate is provided with a water injection hole and an exhaust hole, and a pump is used to inject water into the elbow pressure balance expansion joint through the water injection hole to pressurize it to the required pressure, and then the water injection hole and the exhaust hole are sealed.

4. The device for testing the mechanical impedance transmitted by a bend pressure-balanced expansion joint according to claim 1 or 2, characterized in that: There are four elastic mechanisms, which are arranged on the adjustable frame in a ring, and include an outer airbag seat, an elastic airbag, and an inner airbag seat; One end of the outer airbag seat is connected to the adjustable frame, and the other end is connected to one end of the elastic airbag, the other end of the elastic airbag is connected to the inner airbag seat, and the inner airbag seat is connected to the limiting frame of the limiting mechanism.

5. The device for testing the mechanical impedance transmitted by a bend pressure-balanced expansion joint according to claim 1 is characterized in that: The adjustable frame is a door frame with adjustable size and height, which is fixed on the foundation through a base; the door frame is connected to the elastic mechanism through a through hole.

6. The device for testing the mechanical impedance transmitted by a pressure-balanced expansion joint of a bent pipe according to claim 1, characterized in that: The bottom sealing adapter plate includes a bottom sealing plate, a bottom connecting rib plate, and a bottom adapter plate which are connected in sequence; the bottom sealing plate is sealed and connected to the output end of the elbow pressure balance expansion joint, and the bottom adapter plate is bolted to the three-way force plate, so that the output end blocks the dynamic force from being transmitted to the three-way force plate during the test.

7. The device for testing the mechanical impedance transmitted by a bend pressure-balanced expansion joint according to claim 1 or 6, characterized in that: The three-way force plate is internally provided with a dynamic force sensor for measuring the blocking dynamic force at the output end of the elbow pressure balance expansion joint.

8. The device for testing the mechanical impedance transmitted by a bend pressure-balanced expansion joint according to claim 1 or 6, characterized in that: The lower adapter plate of the force plate is connected to the lower part of the three-way force plate by bolts and fixed on the foundation.

9. A method for testing the mechanical impedance transmitted by a pressure-balanced expansion joint of a bent pipe, characterized in that: The method adopts the bending pipe pressure balance type expansion joint transmission mechanical impedance testing device described in any one of claims 1-8.

10. The method for testing the mechanical impedance transmitted by a pressure-balanced expansion joint of a bent pipe according to claim 9, characterized in that: By adjusting the elastic airbag pressure of the elastic mechanism, the elbow pressure balance expansion joint reaches the initial state; The time domain signals of the dynamic force at the output end measured by the dynamic force sensors at the output end of the elbow pressure balanced expansion joint are added and then converted into signals in the frequency domain by Fourier transform; the time domain signals of the acceleration measured by the acceleration sensor at the input end of the elbow pressure balanced expansion joint are averaged and then converted into signals in the frequency domain by Fourier transform; the output end force in the frequency domain is divided by the corresponding acceleration in the frequency domain, and the result is mass corrected to obtain the transmission acceleration impedance of the elbow pressure balanced expansion joint.

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