LU500884B1

LU500884B1 - Vertical layered acoustic measuring system and method for cross sections

Info

Publication number: LU500884B1
Application number: LU500884A
Authority: LU
Inventors: Yuhang Tian; Bin Zhang; Wen Yan; Zhong Chen
Original assignee: Sanya Inst Of Oceanology Scsio; South China Sea Inst Oceanology Cas
Priority date: 2021-09-16
Filing date: 2021-11-22
Publication date: 2022-05-23
Also published as: CN113866269A; CN113866269B

Abstract

The present invention discloses a vertical layered acoustic measuring system and method for cross sections, and relates to the field of medium acoustic property measuring technologies. The present invention includes a measuring device, a sonograph, and a master control unit. The measuring device includes a base and a main frame. The main frame is disposed on the base and provided with a number of transducer mounting fixtures and at least one sample tube clamping means. The transducer mounting fixture has a degree of freedom to move in a height direction of the main frame and is provided with an oil sac transducer, and the sample tube clamping means is configured to clamp a sample tube. The sonograph is configured to control the oil sac transducer to emit acoustic waves. The master control unit is connected to a motor of the measuring device via a control signal. The present invention can avoid the disturbance caused by flattening the sediments to perform the lateral measurement, and can avoid this case--- what is measured is an average acoustic velocity in the axial direction instead of an acoustic velocity of each layer of the seafloor sediments in situ as deposited vertically.

Description

BL-5331

VERTICAL LAYERED ACOUSTIC MEASURING SYSTEM LU500884

AND METHOD FOR CROSS SECTIONS TECHNICAL FIELD

[0001] The present invention relates to the field of medium acoustic property measuring technologies, and in particular to a vertical layered acoustic measuring system and method for cross sections.

BACKGROUND

[0002] Acoustic parameters of seafloor sediments, such as the propagating velocity and energy attenuation of acoustic waves in the sediments, are important parameters for studying acoustic properties of the sediments, and are also necessary for the theoretical-based acoustic models to perform calculation and tests. Since the acoustic properties of the seafloor sediments are an important factor in affecting the propagation of underwater sound, acquiring the propagating velocity and energy attenuation of acoustic waves in the sediments means a lot to the calculation and studies of the marine environmental models and the discovery and utilization of the marine resources.

[0003] The techniques for measuring acoustic parameters of the seafloor sediments mainly include an acoustic telemetry method, an in-situ acoustic measuring method and a laboratory acoustic measuring method. The acoustic telemetry technique aims to estimate an average acoustic velocity and attenuation of a large volume of strata, and is an indirect method for calculating acoustic properties of the seafloor sediments. The in-situ acoustic measuring method, which is the most direct method for detecting the seafloor, however is researched and developed late in domestic, and the in-situ acoustic measurement requires a long cycle and a high cost, and is vulnerable to the harsh marine environment. The laboratory acoustic measuring method has been widely applied due to its advantages of having a simple technology, a controlled environment, a low cost and, crucially, abilities to acquire seafloor sediment samples directly and to perform the measurement of all aspects of physical, mechanical and acoustic properties.

[0004] The samples collected from the seafloor and employed for measuring the acoustic velocity and acoustic attenuation in laboratories are generally cylindrical sediment samples carried in PVC tubes or organic glass tubes. The measuring method is mainly implemented by transmitting, via a transmitting transducer, an acoustic signal that then passes through the sediments and further receiving the acoustic signal Via a receiving transducer, such that the average acoustic velocity is calculated based on the difference in the propagating distance and propagating time between the acoustic waves. In addition, the acoustic attenuation of the sediments is usually implemented by a coaxial gap attenuation method. 1

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[0005] In practical application, a reference is made to the invention patent CN208043744U that LU500884 discloses self-adaptive acoustic properties measurement for columnar samples of sediments. This method is mainly embodied in that the transducer is mounted on two ends of the sample tube to perform the lateral measurement, and the sample tube is placed horizontally to measure the acoustic properties of the sediments in the tube. If the measurement is performed with this method, the sediments on the seafloor surface may be caused to flow, and it can be seen from the cross-section of the sample tube, the sediments cannot fully fill the sample tube, which has a certain impact on the measurement accuracy. Furthermore, the lateral placement indicates that the sediments are mixed. However, the respective seafloor sediments have existed for different periods, and thus, the sediment acoustic velocity as measured is the average value. The samples collected in laboratory may generally include several different kinds of sediment layers, and the lateral measurements cannot achieve an ideal effect in measuring the sediments in each laver and at the demarcation.

[0006] À further reference is made to the invention patent CN1130638SSA that discloses a measuring system and method for automatic dual-hydrophone acoustic properties. According to this method, a transmitting transducer and two receiving hydrophones are emploved to measure the acoustic properties of the sediments and the samples to be measured are also placed horizontally. In addition, this method may also cause the sediments to flow and thus affect the measurement accuracy of properties of the layered sediments, and the presence of a barrier between the transmitting transducer and the two hydrophones may also affect the measurement.

[0007] À further reference is made to the invention patent CN208520818U that discloses an acoustic profile measuring device for seafloor sediments, and this method is mainly embodied in that the transducer is mounted on each side of the sample tube body to measure the acoustic properties of the sediments. The measurement according to this method can solve the problem in the lateral measurement regarding that the sediments cannot fully fill the cross-section. However, this method can only satisfy a single size of sample tube, whereas, the sample tubes as collected do not have a constant diameter, which may either be small or large, and the positioning error may vary with the sample tubes having different sizes. Moreover, it is troublesome to assemble and disassemble the transducer of this device, which brings inconvenience to the multi-frequency measurement. In addition, since this device is a manual device, the measurement accuracy may be greatly affected by human, which mainly includes the vertical displacement of the transducer during the measurement.

2

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SUMMARY LU500884

[0008] In response to the deficiencies in the prior art, the present invention provides a vertical layered acoustic measuring system for cross sections,

[0009] Fo achieve the object above, the technical solution of the present invention specifically includes:

[0010] À vertical layered acoustic measuring system for cross sections, comprising:

[0011] à measuring device, comprising:

[0012] à base; and

[0013] a main frame, disposed on the base and provided with a number of transducer mounting fixtures and at least one sample tube clamping means, wherein the transducer mounting fixture has a degree of freedom to move in a height direction of the main frame and is provided with an oil sac transducer, and the sample tube clamping means is configured to clamp a sample tube;

[0014] à sonograph, configured to control the oil sac transducer to emit acoustic waves; and

[0015] a master control unit, connected to a motor of the measuring device via a control signal.

[0016] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, the main frame comprises:

[0017] à motor, disposed at an upper end of the main frame; and

[0018] à lifting lead screw module, disposed in the main frame, wherein an output shaft of the motor is connected to an input power end of the lifting lead screw module, a slider of the lifting lead screw module is connected to the transducer mounting fixture, and the lifting lead screw module has a degree of freedom to move in the height direction of the main frame under a power drive of the motor.

[0019] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, the main frame is further provided with:

[0020] a magnetic railings ruler, disposed along the height direction of the main frame and provided with a displacement sensor and a temperature sensor, wherein the displacement sensor and the temperature sensor are connected to the master control unit of the system via control signals.

[0021] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, the transducer mounting fixtures comprises:

[0022] à first forward-reverse trapezoidal lead screw module, horizontally disposed on the main frame; and

[0023] two sets of transducer rotating means, disposed symmetrically and respectively mounted on two sliding components of the first forward-reverse trapezoidal lead screw module, wherein the transducer rotating means comprises a mounting frame and a plurality of shaft clamps, and 3

BL-5331 wherein the mounting frame is connected to the sliding component via a first bracket and LU500884 rotatably disposed on the bracket, and the plurality of shaft clamps are symmetrically disposed along a center line of the mounting frame, and provided with oil sac transducers.

[0024] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, the mounting frame is rotatably connected to the bracket via a positioning nut, and defines positions of the transducer rotating means by inserting and removing an indexing pin,

[0025] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, the sample tube clamping means comprises:

[0026] & second forward-reverse trapezoidal lead screw module, horizontally disposed on the main frame; and

[0027] two sets of V-blocks, disposed symmetrically and respectively connected to the two sliding components of the first forward-reverse trapezoidal lead screw module via a second bracket.

[0028] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, each of the first forward-reverse trapezoidal lead screw module and the second forward-reverse trapezoidal lead screw module comprises:

[0029] a mounting plate, provided with a blocking plate at each of its two ends; and

[0030] & forward-reverse trapezoidal lead screw, disposed along a length direction of the mounting plate, and taking a plane where a central cross-section per se lies as a symmetry plane, with opposite spiral directions of the threads of the lead screws at two ends, wherein the threads of the lead screws having opposite spiral directions are connected with sliding components respectively, and the sliding components move in opposite or separate directions by turning a handwheel on a side.

[0031] Furthermore, for the vertical layered acoustic measuring system for cross sections as described above, the oil sac transducer comprises:

[0032] à transducer, having an acoustic transmitting and receiving sensor:

[0033] a clamp, fixed to an outer side of the transducer via a positioning shoulder; and

[0034] an oil sac, which is flexible, fixed by the clamp, and filled with oil.

[0035] À vertical layered acoustic measuring method for cross sections, based on the vertical layered acoustic measuring system for cross sections according to any one of claims 1-8, and comprising:

[0036] fixing a sample tube to be measured to a sample tube clamping means, and fixing oil sac transducers of different frequencies to the transducer mounting fixtures respectively;

[0037] generating, based on a target position of the sample tube to be measured, a first control command by a master control unit and transmitting the first control command to a controller of a 4

BL-5331 motor, wherein the first control command comprises measuring positions of the oil sac LU500884 transducers;

[0038] wherein the first control command is configured to instruct the motor to drive the transducer mounting fixtures to move to the measuring positions;

[0039] receiving displacement amount and temperature data as collected by a displacement sensor and a temperature sensor respectively, and showing the data to an operator via a display,

[0040] generating and then transmitting a second control command to a sonograph, wherein the second control command comprises an acoustic measuring operation of the où sac transducers,

[0041] the second control command is configured to instruct the oil sac transducer to complete the acoustic measuring operation upon the oil sac transducer arniving at the measuring position and then feedback acoustic measurement data to the sonograph;

[0042] measuring the sample tube at different positions in sequence;

[0043] repeating the aforesaid steps to perform measurement by replacing inner and outer oil sac transducers with a transducer rotating means;

[0044] replacing the sample tube filled with water for calibration experiments; and

[0045] comparing differences in acoustic properties between sediments under different sizes of sample tubes and at different frequencies.

[0046] The vertical layered acoustic measuring method for cross sections according to claim 9, wherein comparing the differences in acoustic properties between the sediments under different sizes of sample tubes and at different frequencies specifically comprises: S-S1-D 26 d t, = Te + o + = S ô wo S-S1-D 26 d “Te Toe S ô P ;

[0047] wherein the sample tube has a wall thickness of 6, an outer diameter of D, and an inner diameter of d; a measuring distance of a shoulder of the transducer is S, and a shoulder width is S1; a velocity of acoustic waves passing through a wall of the sample tube is Cs, a velocity of the acoustic waves passing through water is Cy, a velocity of the acoustic waves passing through the sediments is Cp, and a velocity of the acoustic waves passing through an oil sac is Cs; and travel time of the acoustic waves is t1 when the sample tube is filled with water and is t2 when the sample tube is filled with the sediments;

[0048] an acoustic velocity in the sediments as obtained by subtracting the aforesaid two equations is: co Co 1-C,At/d

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[0049] and acoustic attenuation in the sediments 15: : oe LU500884 jee Gp = = 18817 Ve.)

[0050] wherein a refers to an acoustic attenuation coefficient of the sediments in a unit of dB/m; ew, es refer to receiving voltages of water and the sediments respectively as collected in the same channel in a unit of v; and e,/es refers to an energy ratio of the water to the sediments.

[0051] The beneficial effect of the present invention compared with the prior art lies in following aspects.

[0052] 1. The requirement of layered measurement in a vertical direction is met, and the sediment sample tube is placed vertically, which can ensure that the sediments fully fill the cross-section of the sample tube.

[0053] 2. The touch screen controls the motor by PLC to drive the lead screw, such that the transducer can move to the specified position, and the touch screen is equipped with a fine- tuning button and a steeping button, which greatly improves the movement accuracy.

[0054] 3. The device is equipped with a displacement sensor of the magnetic railings ruler and a pt100 temperature sensor, which can timely feedback the height of the transducer and the temperature data of the sediments to the touch screen.

[0055] 4. This device is designed to be compatible with the transducer clamping means of six frequencies, which basically meets the frequency requirements as required in measuring acoustic properties of the sediments. The operator can clamp six pairs of transducers at one time, and switches to a transducer at the corresponding frequency for each measurement. When the measurement of the transducer at inner side of the rotating frame is completed, the remaining three pairs of transducers can be switched by only rotating the rotating frame.

[0056] S. For the sample tube clamping means, the V-block as designed can satisty the sample tube having a diameter from 70 to 110mm, which facilitates the assembling and disassembling, and the sample tube can be clamped by swinging the handwheel.

[0057] 6. The transducer clamping means moves on the lifting lead screw via a lifting slider set, and the guiding effect of the lead screw ensures the verticality requirement of the transducer clamping means.

[0058] 7. The forward-reverse trapezoidal lead screw structure, which is provided in the transducer clamping means and mounted on the base, effectively ensures the co-axiality error between the axis of the sample tube and the midline of the transducer set. Therefore, the sample tube and the transducer can be disposed in the same axis only if it ensures that the axis of the transducer coincides with the axis of the V-block and that the inner and outer transducers are symmetrical with respect to the axis 2. 6

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[0059] 8. The indexing pin and positioning bolt as designed in the transducer rotating means can effectively restrict the rotation angle and thereby ensure the stability of the whole clamping. 200886 means.

[0060] 9. The vertical layered acoustic measuring method for cross sections can effectively eliminate the influence of walls of the sample tube on the acoustic velocity.

[0061] 10. For the design of the oil sac transducer, the oil sac is flexible and can be deformed to fit on the cylindrical wall of the sample tube to exclude air; the oil is an impedance matching medium and can well match the transducer and walls of the sample tube; the positioning shoulder is configured to perform clamping and positioning and measure the relative distance of the transducer, and the oil sac in the oil sac transducer acts as a coupling agent, which indirectly ensures the contact between the transducer and walls of the tube.

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] To describe the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0063] FIG. 1 is a schematic block diagram of a principle of a vertical layered acoustic measuring system for cross sections according to an embodiment of the present invention;

[0064] FIG. 2 is a schematic diagram of a view of a layered acoustic measuring device for vertical cross-sections from a first visual angle according to an embodiment of the present invention;

[0065] FIG. 3 is a schematic diagram of a view of the vertical layered acoustic measuring system for cross sections from a second visual angle according to an embodiment of the present invention,

[0066] FIG. 4 is a schematic diagram of a view of a forward-reverse trapezoidal lead screw module from a first visual angle according to an embodiment of the present invention;

[0067] FIG. 5 is a schematic diagram of a view of a forward-reverse trapezoidal lead screw module from a second visual angle according to an embodiment of the present invention;

[0068] FIG. © is a schematic structural diagram of a tube clamping means according to an embodiment of the present invention;

[0069] FIG. 7 is a schematic mounting diagram of a displacement sensor of a magnetic railings ruler according to an embodiment of the present invention; 7

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[0070] FIG. 8 is a schematic structural diagram of an oil sac transducer according to an LU500884 embodiment of the present invention:

[0071] FIG. 9 is a schematic diagram of a principle for calculating an acoustic velocity of sediments according to an embodiment of the present invention, and

[0072] FIG. 10 is a schematic diagram of a principle for guaranteeing a coaxial error between a transducer and a sample according to an embodiment of the present invention.

[0073] Reference signs: 1. Stepping motor; 2. Lifting lead screw module; 3. Upper positioning means; 4. First forward-reverse trapezoidal lead screw module; S. Transducer rotating means; 6. Second forward-reverse trapezoidal lead screw module; 7. Sample tube; 8. Transducer mounting fixture, 9. V-block; 10. Base; 11. Magnetic railings ruler; 12. Foot cup, 13. Handwheel, 14. Slider; 15. Forward-reverse trapezoidal lead screw; 16. Sliding rail, 17. Mounting plate; 18. Stopping block; 19. Shaft clamp; 20. Oil arc transducer set (6 pairs in total}, 21. Shaft clamp fixing out; 22. Bracket; 23. Indexing pin, 24. Positioning bolt; 25. Positioning hole (the positioning hole being also provided at the position of the indexing pin}, 26. Transducer mounting frame, 27. V-block mounting frame; 28 V-block, 29. Magnetic railings ruler; 30. Reading head of magnetic railings ruler; 31. Mounting block of magnetic railings ruler.

DETAILED DESCRIPTION

[0074] Technical solutions of embodiments of the present invention will be described clearly and completely below in combination with the accompanying drawings in embodiments of the present invention. It is obvious that the described embodiments are only a part of embodiments of the present invention, not all embodiments of the present invention. All the other embodiments achieved by those of ordinary skills in the art, based on the embodiments of the present disclosure without creative work, shall fall within the protection scope of the present disclosure.

[0075] Examples:

[0076] It is to be noted that terms "first", "second", and the like used in Description, Claims and the accompanying drawings are used for the purpose of distinguishing similar objects instead of indicating a particular order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described herein can be implemented in an order other than the order illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof in embodiments of the present invention are intended to cover the inclusion in a non-exclusive manner. For example, the process, method, system, product, or apparatus that includes a series of 8

BL-5331 steps or units need not to be limited to those steps or units as clearly listed, but may include other steps or units not clearly listed or inherent to those process, method, product or apparatus. 17000886

[0077] It should be understood that, orientation or position relationships indicated by the terms "center", "longitudinal", "transversal", "length", "width", "thickness", "above", "below", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", or the like are based on the orientation or position relationships as shown in the drawings, which are merely for ease of the description of the present invention and simplifying the description rather than indicating or implying that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation. Therefore, these terms should not be understood as a limitation to the present invention.

[0078] In the description of the present invention, "a plurality of" refers to at least two in number, which may for example refer to two, three or the like, unless otherwise specifically defined. Furthermore, unless otherwise specified and defined, the terms "mount", "connected with", "connected to" should be comprehended in a broad sense. For example, these terms may be comprehended as that the elements are fixedly connected, detachably connected or integrally connected, or that the components are mechanically connected or coupled, or that the components are directly connected or indirectly connected via an intermediate medium or in an internal communicating manner. The specific meanings about the foregoing terms in the present invention may be understood by those skilled in the art according to specific circumstances.

[0079] Referring to FIGS. 1 to 10, in order to solve the technical problems existing in laboratory measurement of the seafloor sediments, the present invention proposes a vertical layered acoustic measuring system and method for cross sections, which can satisfy following requirements. (1) The measurement is made based on a vertical arrangement of the seafloor sediments in situ, which can avoid the disturbance as caused by flattening the sediments to perform the lateral measurement, and what is measured is the average acoustic velocity in the axial direction instead of the acoustic velocity of each layer of the seafloor sediments in situ as deposited vertically. (2) It is possible to sequentially measure sub-layers of the seafloor sediments as required by moving at any interval, so as to satisfy the observation and comparison of the differences in the acoustic properties between different layers of sediments and to judge the position of the layered interface. (3) Multi-frequency measurement can be realized, such that the measurement data and measurement characteristic support can be given to different measuring methods applying different measurement frequencies. (4) Automatic measurement can be realized, which reduces the inefficiency and error in the measurement by manual movement. The present invention is compatible with transducer probes having various sizes and sediment sample tubes having 9

BL-5331 different sizes, which can not only meet the requirements in measurement accuracy but also can compare the effects of the sample tubes with different sizes on the measurement. 17000886

[0080] The vertical layered acoustic measuring system for cross sections includes a master control unit, a sonograph and a layered acoustic measuring device for vertical cross-sections. The implementation process 1s as shown in FIG. 1 below. Firstly, the master control unit controls the motor of the layered acoustic measuring device for vertical cross-sections via a motor controller, such that the acoustic transducer moves to the point to be measured, and the displacement amount of the transducer and the temperature data of the sample to be measured are fed back to the touch screen via a displacement sensor and a temperature sensor. Then, a command is sent to the sonograph to excite the transducer to emit acoustic waves, and the acoustic wave data 1s received by a receiving transducer and fed back to the sonograph.

[0081] Referring to FIGS. 2-3, the layered acoustic measuring device for vertical cross-sections includes a motor 1, a lifting lead screw module 2, an upper positioning means 3, a first forward- reverse trapezoidal lead screw module 4, a transducer rotating means 5, a second forward-reverse trapezoidal lead screw module 6, a sample tube 7, a transducer mounting fixture 8, a V-block 9, a base 10, a magnetic railings ruler 11, and a foot cup 12. The measuring device includes a base and a main frame. The main frame is disposed on the base and provided with a number of transducer mounting fixtures and at least one sample tube clamping means. The transducer mounting fixture has a degree of freedom to move in a height direction of the main frame and is provided with an oil sac transducer, and the sample tube clamping means is configured to clamp a sample tube. The sonograph is configured to control the oil sac transducer to emit acoustic waves. The master control unit is connected to a motor of the measuring device via a control signal. Thus, the requirement of layered measurement in a vertical direction is met, and the sediment sample tube is placed vertically, which can ensure that the sediment fills cross-sections of the sample tube.

[0082] As an optional implementation, in some embodiments, the main frame includes a motor and a lifting lead screw module. The motor is disposed at an upper end of the main frame, and the lifting lead screw module is disposed in the main frame. An output shaft of the motor is connected to an input power end of the lifting lead screw module, a slider of the lifting lead screw module is connected to the transducer mounting fixture, and the lifting lead screw module has a degree of freedom to move in the height direction of the main frame under a power drive of the motor. The touch screen controls the motor by PLC to drive the lead screw, such that the transducer can move to the specified position, and the touch screen is equipped with a fine- tuning button and a stepping button, which greatly improves the movement accuracy.

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[0083] As an optional implementation, in some embodiments, the first and second forward- reverse trapezoidal lead screw modules as shown in FIG. 4 are each composed of a handwheel 9998 13, a slider 14, a forward-reverse trapezoidal lead screw 15, a sliding rail 16, a mounting plate 17, and a stopping block 18. The so-called forward-reverse trapezoidal lead screw takes a plane where a central cross-section per se lies as a symmetry plane, with opposite spiral directions of the threads of the lead screws at two ends. Therefore, the lead screw goes approaching to the center plane while being rotated clockwise and goes away from the center plane while being rotated counterclockwise, and the stopping block acts as a position defining part to prevent the slider running off the rail.

[0084] As an optional implementation, in some embodiments, the transducer clamping means 5 is composed of a first forward-reverse trapezoidal lead screw module 4 and a transducer rotating means, as shown in FIGS. 5 and 6. The transducer is mounted on the shaft clamp 19 and mounted on the mounting frame 26 by the shaft clamp fixing nut 21, and the transducer is connected to the sonograph. The rotating means consists of a bracket 22, an indexing pin 23, and a positioning nut 24. The inner side of the rotating means is in a measuring mode, and when the measurement at the inner side is completed, the indexing pin is pulled out to exit the position defining mode. Then, the indexing pin is rotated by 180° around the positioning bolt 24 and pressed to enter into the position defining mode, such that a rotating angel of 180° and locking of the rotating means can be ensured. Afterwards, the outer transducer is rotated to the inner side for measurement, such that the measurement of the sample as performed at the same position by six pairs of transducers having different frequencies can be completed. The device constrains the rotating angle of 180° mainly by the indexing pin 23 and the positioning nut 24. The transducer clamping means moves on the lifting lead screw via the lifting slider set, and the guiding effect of the lead screw ensures the verticality requirement of the transducer clamping means. The forward-reverse trapezoidal lead screw structure, which is provided in the transducer clamping means and mounted on the base, effectively ensures the co-axiality error between the axis of the sample tube and the midline of the transducer set. Therefore, the sample tube and the transducer can be disposed in the same axis only if it ensures that the axis of the transducer and the axis of the V-block coincide and that the inner and outer transducers are symmetrical with respect to the axis 2. Furthermore, the indexing pin and positioning bolt as designed in the transducer rotating means can effectively restrict the rotation angle and thereby ensure the stability of the whole clamping means.

[0085] The sample tube clamping means as shown in FIG. 7 is composed of a second forward- reverse trapezoidal lead screw module 6, a V-block mounting frame 27, and a V-block 28. The V-block moves approaching to the center to clamp the sample tube when the handwheel is turned. 11

BL-5331 The V-block is applicable for sample tubes having a diameter from 75mm to 110mm, which facilitates the assembling and dissembling, and the sample tubes are clamped by rotating the 00886 handwheel.

[0086] As an optional implementation, in some embodiments, the main frame 1s further provided with a magnetic railings ruler. The magnetic railings ruler is disposed along the height direction of the main frame and provided with a displacement sensor and a temperature sensor. The displacement sensor and the temperature sensor are connected to the master control unit of the system via control signals. The displacement sensor of the magnetic railings ruler is assembled as shown in FIG. 9. The reading head 30 of the magnetic railings ruler slides on the magnetic railings ruler 28 and is connected to the first forward-reverse trapezoidal lead screw module via the magnetic railings ruler mounting block. That is, the reading head of the magnetic railings ruler and the transducer clamping means move synchronously to detect the movement displacement of the transducer. The device is equipped with the displacement sensor of the magnetic railings ruler and a pt100 temperature sensor, such that the height of the transducer and the temperature data of the sediments can be fed back to the touch screen timely.

[0087] As an optional implementation, in some embodiments, the specific structure of the oil sac transducer is as shown in FIG. 9. The oil sac transducer is composed of a transducer, a clamp, an oil sac, oil, a positioning shoulder and conductive wires. The oil sac is flexible and can be deformed to fit on the cylindrical wall of the sample to exclude air. The oil is an impedance matching medium, and can well match the transducer and walls of the sample tube. The transducer is a basic acoustic transmitting and receiving transducer. The positioning shoulder is configured to perform clamping and positioning and measure the relative distance of the transducer. The conductive wires are electric wires for transmitting and receiving the electrical signal. The set of oil sac transducers 20 consists of six pairs of oil sac transducers having different frequencies, and is divided into two groups each of which comprises three pairs of oil sac transducers that are distributed symmetrically and mounted on the transducer clamping means 4. The frequencies of the six pairs of oil sac transducers are SOHz, 100Hz, 200Hz, 300Hz, 400Hz, 500Hz, respectively. It is possible to design more pairs of oil sac transducers, and the most basic state is to include one pair, which may also be two, three, four, five or six pairs depending on the frequency of the transducer under study. For the design of the oil sac transducer, the oil sac is flexible and can be deformed to fit on the cylindrical wall of the sample tube to exclude air; the oil is an impedance matching medium and can well match the transducer and walls of the sample tube; the positioning shoulder is configured to perform clamping and positioning and measure the relative distance of the transducer; and the oil sac in the oil sac transducer acts as a coupling agent, which indirectly ensures the contact between the transducer 12

BL-5331 and walls of the tube. This device is designed to be compatible with the transducer clamping means having six frequencies, which basically meets the frequency requirements as required in 200886 measuring acoustic properties of the sediments. The operator can clamp six pairs of transducers at one time, and switches to a transducer having the corresponding frequency for each measurement. When the measurement of the transducer at inner side of the rotating frame is completed, the remaining three pairs of transducers can be switched by only rotating the rotating frame.

[0088] The transducer clamping means 4 is composed of a forward-reverse trapezoidal lead screw module 9 and a transducer rotating frame 10. The transducer is mounted on the rotating frame via a dedicated fixture and connected to the sonograph. The inner side of the rotating frame is in the measuring state, and when the measurement at the inner side is completed, the rotating means is rotated by 180° to rotate the outer transducer to the inner side for measurement, such that the measurement of the sample as performed at the same position by six pairs of transducers having different frequencies can be completed.

[0089] The specific structure of the oil sac transducer is shown in FIG. 9. The oil sac transducer is composed of a transducer, a clamp, an oil sac, oil, a positioning shoulder and conductive wires. The oil sac is flexible and can be deformed to fit on the cylindrical wall of the sample to exclude air. The oil is an impedance matching medium, and can well match the transducer and walls of the sample tube. The transducer is a basic acoustic transmitting and receiving transducer. The positioning shoulder is configured to perform clamping and positioning and measure the relative distance of the transducer (corresponding to the distance d in the acoustic speed in combination with the supplementary calculation equation). The conductive wires are electric wires for transmitting and receiving the electrical signal.

[0090] The sample tube clamping means is composed of a V-block 12, a sample tube 13, and a forward-reverse trapezoidal lead screw module 14. The transducer clamping means is connected to the slider of the lifting screw module, and the sample tube clamping means is fixed to the base by screws. During the operation, the handwheel of the sample tube clamping means is swung to clamp the sample tube, and the motor drives the lifting screw to move and control the up and down movement of the transducer set. When the transducer set arrives at the point to be measured, the sonograph issues a collecting command to start the acoustic measurement.

[0091] The method for calculating acoustic velocity of the sediments is as follows:

[0092] Referring to FIG. 10, it is assumed that: the sample tube has a wall thickness of 6, an outer diameter of D, and an inner diameter of d; a measuring distance of a shoulder of the transducer is S, and a shoulder width is S1; a velocity of acoustic waves passing through a wall of the sample tube is Cs, a velocity of the acoustic waves passing through water is Cy, a velocity 13

BL-5331 of the acoustic waves passing through the sediments 1s Cp, and a velocity of the acoustic waves passing through an oil sac is Cs; and travel time of the acoustic waves is tı when the sample tube. 900998 is filled with water and is to when the sample tube is filled with the sediments. Then, following equations are acquired: y 58120 26, d Cs C, C, , y 3751-0283, d Cs Cs; Cr ,

[0093] An acoustic velocity in the sediments as obtained by subtracting the aforesaid two equations is: C,= _ 6 1-C,At/d

[0094] and acoustic attenuation in the sediments 1s: {ee Op = Fe le, /

[0095] where a, refers to an acoustic attenuation coefficient of the sediments in a unit of dB/m; ew, es refer to receiving voltages of water and the sediments respectively as collected in the same channel in a unit of v; and e,/es refers to an energy ratio of the water to the sediments.

[0096] The vertical layered acoustic measuring method for cross sections can effectively eliminate the influence of walls of the sample tube on the acoustic velocity.

[0097] The specific implementation may include following steps:

[0098] Step 1: placing the sample tube 7 filled with sediments vertically on the base 10 of the device, and adjusting the handwheel of the sample tube clamping means to clamp the sample tube 7;

[0099] Step 2: clamping the six pairs of transducers having different frequencies with the shaft clamps 19, and then connecting the transducers to the sonograph;

[00100] Step 3: operating the touch screen to input the distance to be moved, controlling the motor 1 to rotate to drive the transducer to move, adjusting the fine-tuning button based on the displacement data fed back by the magnetic railings ruler to move the transducer to the desired position, and recording the temperature data fed back by the temperature sensor in real time;

[00101] Step 4: turning on the sonograph, controlling the transmitting transducer to transmit acoustic waves, and receiving data via the receiving transducer and feeding back the data to the sonograph, such that one experiment of one frequency at this point to be measured is completed; 14

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[00102] Step 5: operating the touch screen and pressing the stepping button to sequentially measure different positions of the sample until the measurement of all the positions of the sample 200886 is completed,

[00103] Step 6: performing the measurement by switching the transducer sets having different frequencies, and repeating the aforesaid steps until measurement of all the transducers on the inner side of the rotating frame are completed;

[00104] Step 7: pulling out the indexing pin, rotating the rotating frame by 180°, and then pressing the indexing pin again to complete one rotation, such that the transducers at inner and outer sides are switched, and the measurement of the three pairs of transducer sets at the outer side can be completed;

[00105] Step 8: placing the sample tube 7 fully filled with water on the device for measurement, performing the water calibration experiment, and repeating the aforesaid steps;

[00106] Step 9: resetting the device after completing the measurement, and reading the waveform data to perform data analysis; and

[00107] Step 10: comparing differences in acoustic properties between sediments under different sizes of sample tubes and at different frequencies.

[00108] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "examples", "specific examples", or "some examples", and the like indicates that the specific feature, structure, material or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the aforesaid terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics as described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and group the different embodiments or examples and the features of the different embodiments or examples described in this specification without contradicting each other.

[00109] The aforesaid embodiments are only to illustrate the technical concept and features of the present invention, and are intended to enable a person of ordinary skill in the art to understand the content of the present invention and to implement the present invention accordingly, and not intended to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the substance of the content of the present invention shall be covered by the protection scope of the present invention.

Claims

BL-5331 CLAIMS LU500884 What is claimed is:

1. A vertical layered acoustic measuring system for cross sections, comprising: a measuring device, comprising: a base; and a main frame, disposed on the base and provided with a number of transducer mounting fixtures and at least one sample tube clamping means, wherein the transducer mounting fixture has a degree of freedom to move in a height direction of the main frame and is provided with an oil sac transducer, and the sample tube clamping means is configured to clamp a sample tube; a sonograph, configured to control the oil sac transducer to emit acoustic waves; and a master control unit, connected to a motor of the measuring device via a control signal.

2. The vertical layered acoustic measuring system for cross sections according to claim 1, wherein the main frame comprises: a motor, disposed at an upper end of the main frame; and a lifting lead screw module, disposed in the main frame, wherein an output shaft of the motor is connected to an input power end of the lifting lead screw module, a slider of the lifting lead screw module is connected to the transducer mounting fixture, and the lifting lead screw module has a degree of freedom to move in the height direction of the main frame under a power drive of the motor.

3. The vertical layered acoustic measuring system for cross sections according to claim 2, wherein the main frame is further provided with: a magnetic railings ruler, disposed along the height direction of the main frame and provided with a displacement sensor and a temperature sensor, wherein the displacement sensor and the temperature sensor are connected to the master control unit of the system via control signals.

4. The vertical layered acoustic measuring system for cross sections according to claim 3, wherein the transducer mounting fixture comprises: a first forward-reverse trapezoidal lead screw module, horizontally disposed on the main frame; and 16

BL-5331 two sets of transducer rotating means, disposed symmetrically and respectively mounted on two sliding components of the first forward-reverse trapezoidal lead screw module, wherein the 200886 transducer rotating means comprises a mounting frame and a plurality of shaft clamps, and wherein the mounting frame is connected to the sliding component via a first bracket and rotatably disposed on the bracket, and the plurality of shaft clamps are symmetrically disposed along a center line of the mounting frame, and provided with oil sac transducers.

5. The vertical layered acoustic measuring system for cross sections according to claim 4, wherein the mounting frame is rotatably connected to the bracket via a positioning nut, and defines positions of the transducer rotating means by inserting and removing an indexing pin.

6. The vertical layered acoustic measuring system for cross sections according to claim 4, wherein the sample tube clamping means comprises: a second forward-reverse trapezoidal lead screw module, horizontally disposed on the main frame; and two sets of V-blocks, disposed symmetrically and respectively connected to the two sliding components of the first forward-reverse trapezoidal lead screw module via a second bracket.

7. The vertical layered acoustic measuring system for cross sections according to claims 1-5, wherein each of the first forward-reverse trapezoidal lead screw module and the second forward- reverse trapezoidal lead screw module comprises: a mounting plate, provided with a blocking plate at each of its two ends; and a forward-reverse trapezoidal lead screw, disposed along a length direction of the mounting plate, and taking a plane where a central cross-section per se lies as a symmetry plane, with opposite spiral directions of the threads of the lead screws at two ends, wherein the threads of the lead screws having opposite spiral directions are connected with sliding components respectively, and the sliding components move in opposite or separate directions by turning a handwheel on a side.

8. The vertical layered acoustic measuring system for cross sections according to claims 1-5, wherein the oil sac transducer comprises: a transducer, having an acoustic transmitting and receiving sensor; a clamp, fixed to an outer side of the transducer via a positioning shoulder; and an oil sac, which 1s flexible, fixed by the clamp, and filled with oil.

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9. A vertical layered acoustic measuring method for cross sections, based on the vertical layered acoustic measuring system for cross sections according to any one of claims 1-8, and 200886 comprising: fixing a sample tube to be measured to a sample tube clamping means, and fixing oil sac transducers of different frequencies to the transducer mounting fixtures respectively; generating, based on a target position of the sample tube to be measured, a first control command by a master control unit and transmitting the first control command to a controller of a motor, wherein the first control command comprises measuring positions of the oil sac transducers; wherein the first control command is configured to instruct the motor to drive the transducer mounting fixtures to move to the measuring positions respectively; receiving displacement amount and temperature data as collected by a displacement sensor and a temperature sensor respectively, and showing the data to an operator via a display; generating and then transmitting a second control command to a sonograph, wherein the second control command comprises an acoustic measuring operation of the oil sac transducers; wherein the second control command is configured to instruct the oil sac transducer to complete the acoustic measuring operation upon the oil sac transducer arriving at the measuring position and then feedback acoustic measurement data to the sonograph; measuring the sample tube at different positions in sequence; repeating the aforesaid steps to perform measurement by replacing inner and outer oil sac transducers with a transducer rotating means; replacing the sample tube filled with water for calibration experiments; and comparing differences in acoustic properties between sediments under different sizes of sample tubes and at different frequencies.

10. The vertical layered acoustic measuring method for cross sections according to claim 9, wherein comparing the differences in acoustic properties between the sediments under different sizes of sample tubes and at different frequencies specifically comprises: Li A 20, d Cs C, CG, , ‘ _S$-81-D 26 d Cs Cs C, , where the sample tube has a wall thickness of 6, an outer diameter of D, and an inner diameter of d; a measuring distance of a shoulder of the transducer is S, and a shoulder width is S1; a velocity of acoustic waves passing through a wall of the sample tube is Cs, a velocity of the 18

BL-5331 acoustic waves passing through water is Cy, a velocity of the acoustic waves passing through the sediments is Cp, and a velocity of the acoustic waves passing through an oil sac is Cs; and travel 09998 time of the acoustic waves is t1 when the sample tube is filled with water and is t2 when the sample tube is filled with the sediments; an acoustic velocity in the sediments as obtained by subtracting the aforesaid two equations is: C=C 1-C,At/d and acoustic attenuation in the sediments is: fe) Fp = 12619 \es where a, refers to an acoustic attenuation coefficient of the sediments in a unit of dB/m; ev, es refer to receiving voltages of water and the sediments respectively as collected in the same channel in a unit of v; and ew /es refers to an energy ratio of the water to the sediments. 19