Device for accurately calibrating delay time of sound wave detector system

Abstract

A device for accurately calibrating delay time of a sound wave detector system relates to the field of integrity detection of a bored pile sound wave transmission method and comprises a silencing water tank, a guide rail, a fixed connecting rod, a movable connecting rod and two transducers. The two transducers are oppositely mounted at the lower ends of the fixed connecting rod and the movable connecting rod respectively; the upper end of the fixed connecting rod is fixed at the left end part of the guide rail, the guide rail is provided with a capacitive grating sensor graduated scale, and the capacitive grating sensor graduated scale takes the horizontal position of the end surface of the transducer on the fixed connecting rod as a zero graduation reference surface; the upper end of the movable connecting rod is installed on the capacitive grating sensor calibrated scale through a sliding block, and the sliding block is fixedly connected with a capacitive grating sensor reader. When the movable connecting rod is moved to enable the end faces of the two transducers to be attached, the reading of the reading device of the capacitive grating sensor is zero. The measuring device is high in measuring precision, superior to standard requirements, capable of achieving measurement at any interval, suitable for sound wave detector transducers of different models and sizes, easy, convenient and rapid to operate and easy to apply and popularize.

Description

Technical Field

[0001] The utility model relates to the technical field of integrity detection of bored piles by acoustic wave transmission method, in particular to a device for accurately calibrating the delay time of an acoustic wave detector system. Background Art

[0002] With the rapid development of my country's socialist economic construction, railway, highway, civil construction and other engineering projects have ushered in new opportunities and challenges, and the quality of engineering projects has also attracted more and more attention. In foundation engineering, pile foundations have been widely used due to their superior performance such as high bearing capacity, small settlement, good seismic performance and wide application range. In recent years, the annual number of piles used in pile foundation projects in my country has reached 5 million. As an underground hidden project, pile foundations are generally located underground or underwater, with high technical requirements and great construction difficulty. Its construction quality is difficult to control, and it is easy to have defects such as necking, mud inclusion, honeycomb, sediment and even broken piles. At the same time, the quality of the foundation pile directly affects its bearing capacity and the stability of the superstructure. Therefore, the quality inspection of the foundation pile has become the most critical part of engineering quality control. At present, the common methods for detecting the integrity of foundation piles include core drilling method, low strain method, acoustic wave transmission method, etc. Among them, the acoustic wave transmission method is widely used in the integrity detection of large-diameter cast-in-place piles.

[0003] According to the "Technical Code for Inspection of Railway Engineering Pile Foundations" (TB10218-2019), "Technical Code for Inspection of Highway Engineering Pile Foundations" (JTG / T 3521-2020) and "Technical Code for Inspection of Building Foundations" (JGJ 106-2014), the acoustic wave transmission method is currently mainly used to detect the location, range and degree of defects in the pile body of concrete bored piles, and determine the integrity category of the pile body. It uses the transmission principle of sound waves to detect the condition of the concrete medium of the pile body. It is suitable for situations where acoustic detection tubes have been pre-buried during the pouring of the piles.

[0004] The preparation for the sound wave transmission method test in highway, railway and building specifications all require the calibration of the system delay time, and the calibration method is calibration in clear water. Among them, Article 10.3.2 of the "Technical Specifications for Pile Testing of Highway Engineering" (JTG / T 3521-2020) clearly states: To ensure the test accuracy, the measurement error of the distance between the two transducers shall not exceed 0.5%, and the measurement points shall not be less than 5 points. Since the measurement of the distance between the two transducers is generally carried out in clear water, the measurement accuracy is difficult to meet the specification requirements, and the propagation speed of ultrasonic waves in clear water is relatively fast, which can easily cause inaccurate measurement of the delay time of the acoustic wave detector system, which has a great impact on the integrity test results. Usually, a ruler is used to measure the transducer spacing underwater, with a general accuracy of ±3mm. The speed of ultrasonic waves in clear water is 1500m / s, then the test system delay time is at least 2μs, and the general acoustic wave detector system delay time is about 12μs. Obviously, it is difficult to meet the requirements for the spacing accuracy using a ruler.

[0005] The utility model patent application with the authorization announcement number CN207114490U discloses an "auxiliary device for ultrasonic detection of foundation piles". Although this device can calibrate the delay time of the acoustic wave detector, the distance between its two transducers is read through a scale plate, with low accuracy and it is difficult to meet the specification requirements. The invention patent application with the application publication number CN112305068A discloses an "ultrasonic zero acoustic time test tooling and its test method". Although this application can accurately calibrate the delay time of the acoustic wave detector, the distance between its two transducers is fixed, lacking flexibility and not applicable to transducers of different diameters. The utility model patent application with the authorization announcement number CN212078036U discloses a "high-frequency anechoic water tank device". Although this device can relatively accurately calibrate the delay time of the acoustic wave detector, it cannot zero the distance between the transducers, and the distance measurement is not flexible and fast enough, with an unclear application effect. The utility model patent with the authorization announcement number CN206235600U discloses an "anechoic water tank device for calibrating the system delay time of an ultrasonic detector", but this device measures the distance between the transducers using a scale. Since the transducers are placed in clear water and there is a certain distance between the transducers and the scale, it is still difficult to accurately measure the distance and cannot meet the specification requirements. Summary of the Invention

[0006] The technical problem to be solved by the present utility model is: a device for accurately calibrating the system delay time of an acoustic wave detector that can achieve arbitrary distance measurement, high accuracy, and simple and fast operation.

[0007] The technical solution to solve the above technical problem is: a device for accurately calibrating the system delay time of an acoustic wave detector, including an anechoic water tank, a guide rail, two connecting rods, and two transducers; the two connecting rods are respectively a fixed connecting rod and a movable connecting rod, and the two transducers are respectively installed facing each other at the lower ends of the fixed connecting rod and the movable connecting rod, and are both placed in the clear water of the anechoic water tank; the upper end of the fixed connecting rod is fixed at the left end of the guide rail, and a capacitive grating sensor scale is installed on the guide rail, with the horizontal position where the end face of the transducer on the fixed connecting rod is located as the zero scale reference plane; the upper end of the movable connecting rod is installed on the capacitive grating sensor scale through a slider, and a capacitive grating sensor reader is fixedly connected to the slider; when the end faces of the two transducers are fitted by moving the movable connecting rod, the reading of the capacitive grating sensor reader is zero.

[0008] A further technical solution of the present utility model is: the capacitive grating sensor reader is also fastened to the capacitive grating sensor scale through a knob bolt.

[0009] A further technical solution of the present utility model is: the displacement measurement accuracy of the capacitive grating sensor reader is not less than ±0.02 mm.

[0010] A further technical solution of the present utility model is that the transducer is oppositely installed on the fixed connecting rod and the movable connecting rod through elastic buckles that can be applicable to transducers with different diameters.

[0011] A further technical solution of the present utility model is that the inner side of the sound-absorbing water tank is wrapped with sound-absorbing sponge 0.

[0012] Due to the adoption of the above structure, compared with the prior art, a device for accurately calibrating the delay time of an acoustic wave detector system of the present utility model has the following beneficial effects:

[0013] 1. High measurement accuracy

[0014] In the present utility model, two transducers are respectively oppositely installed at the lower ends of the fixed connecting rod and the movable connecting rod. The upper end of the fixed connecting rod is fixed at the left end of the guide rail. A capacitive grating sensor scale is installed on the guide rail. The upper end of the movable connecting rod is installed on the capacitive grating sensor scale through a slider, and a capacitive grating sensor reader is fixedly connected to the slider. Since the lower end of the movable connecting rod is fixedly connected with a transducer and the upper end of the movable connecting rod is fixedly connected with a capacitive grating sensor reader through a slider, when the movable connecting rod is moved, the capacitive grating sensor reader and the transducer located at the upper and lower ends of the movable connecting rod move synchronously. The reading of the capacitive grating sensor reader is the distance between the transducers. The displacement measurement accuracy of the capacitive grating sensor reader is not less than ±0.02 mm, which is completely better than the accuracy required by the specification, and its measurement accuracy is relatively high.

[0015] 2. Can realize measurement of any distance

[0016] Since two transducers are respectively oppositely installed at the lower ends of the fixed connecting rod and the movable connecting rod, the upper end of the fixed connecting rod is fixed at the left end of the guide rail, and the capacitive grating sensor scale on the guide rail takes the horizontal position where the end face of the transducer on the fixed connecting rod is located as the zero scale reference plane; the upper end of the movable connecting rod is installed on the capacitive grating sensor scale through a slider, and a capacitive grating sensor reader is fixedly connected to the slider; when the movable connecting rod is moved to the left so that the end faces of the two transducers are in contact, the reading of the capacitive grating sensor reader is zero; when the movable connecting rod is moved to the right again, the reading of the capacitive grating sensor reader is the distance between the transducers, and an accurate value can be given for any distance. Therefore, the present utility model can realize measurement of any distance.

[0017] 3. Simple and quick operation

[0018] Taking the transducer on the fixed connecting rod as a reference, the present utility model moves the movable connecting rod, and the reading of the capacitive grating sensor reader is the distance between the transducers, and the operation is simple and quick.

[0019] 4. Can be applicable to acoustic wave detector transducers of different models and sizes

[0020] The transducer of the present utility model is installed on the fixed connecting rod and the movable connecting rod in opposite directions through elastic buckles that can accommodate transducers of different diameters. Therefore, it can be applied to transducers of different models and sizes of acoustic wave detectors.

[0021] Next, in combination with the accompanying drawings and embodiments, the technical features of an apparatus for accurately calibrating the delay time of an acoustic wave detector system according to the present utility model will be further described. Description of the Drawings

[0022] Figure 1 : Structural schematic diagram of an apparatus for accurately calibrating the delay time of an acoustic wave detector system according to the present utility model,

[0023] Figure 2 : Figure 1 Enlarged view of part A of

[0024] Figure 3 : Structural schematic diagram of the present utility model when the end faces of two transducers are in contact;

[0025] In the above-mentioned accompanying drawings, the reference numerals are explained as follows:

[0026] 1 - Anechoic water tank, 2 - Guide rail, 3 - Fixed connecting rod, 4 - Movable connecting rod, 5 - Transducer,

[0027] 6 - Grating sensor scale, 7 - Grating sensor reader, 8 - Knob bolt,

[0028] 9 - Elastic buckle, 10 - Sound-absorbing sponge. Detailed Embodiment Embodiment 1:

[0029] Refer to Figures 1-3 , an apparatus for accurately calibrating the delay time of an acoustic wave detector system, including an anechoic water tank 1, a guide rail 2, a fixed connecting rod 3, a movable connecting rod 4, and two transducers 5; wherein,

[0030] The inside of the sound-absorbing water tank 1 is wrapped with sound-absorbing sponge 10, filled with clear water, and placed on a horizontal ground. The guide rail 2 is fixed above the sound-absorbing water tank 1, and a capacitive sensor scale 6 is installed on the guide rail 2. The two transducers 5 are respectively installed at the lower ends of the fixed connecting rod 3 and the movable connecting rod 4 in opposite directions through elastic buckles 9 that can accommodate transducers of different diameters, and are both placed in the clear water of the sound-absorbing water tank 1. The upper end of the fixed connecting rod 3 is fixed at the left end of the guide rail 2. The capacitive sensor scale 6 takes the horizontal position where the end face of the transducer 5 on the fixed connecting rod 3 is located as the zero scale reference plane. The upper end of the movable connecting rod 4 is installed on the capacitive sensor scale 6 through a slider. A capacitive sensor reader 7 is fixedly connected to the slider, and the capacitive sensor reader 7 can also be fastened to the capacitive sensor scale 6 through a knob bolt 8. The displacement measurement accuracy of the capacitive sensor reader 7 is not less than ±0.02 mm. When the end faces of the two transducers 5 are brought into contact by moving the movable connecting rod 4, the reading of the capacitive sensor reader 7 is zero.

[0031] The capacitive sensor scale 6 and the capacitive sensor reader 7 belong to conventional technologies and will not be elaborated here.

[0032] The working process of the present utility model is as follows:

[0033] First step, install the two transducers on the fixed connecting rod 3 and the movable connecting rod 4 respectively. Connect the transducer connecting wires to the main unit of the acoustic wave detector, set the detection parameters, and turn on the switch of the capacitive sensor reader 7.

[0034] Second step, make the two transducers contact each other by sliding the movable connecting rod 4, and press the zero button of the capacitive sensor reader 7 to make the reading of the capacitive sensor reader zero.

[0035] Third step, by sliding the movable connecting rod 4, measure the acoustic time at different transducer spacings in turn, not less than 5, and record the reading of the capacitive sensor reader 7 and the corresponding acoustic time.

[0036] Fourth step, make a time-distance curve of linear regression for the measured distance-acoustic time data to obtain the system delay time between the two transducers.

[0037] Fifth step, replace the next pair of transducers for measurement until the system delay times between all transducers are obtained.

Claims

1. A device for precisely calibrating the delay time of an acoustic wave detector system, comprising an anechoic water tank (1), a guide rail (2), two connecting rods, and two transducers (5); characterized in that: The two connecting rods are respectively a fixed connecting rod (3) and a movable connecting rod (4). Two transducers (5) are respectively installed facing each other at the lower ends of the fixed connecting rod (3) and the movable connecting rod (4), and both are placed in the clear water of the anechoic water tank (1); the upper end of the fixed connecting rod (3) is fixed at the left end of the guide rail (2), and a capacitive grating sensor scale (6) is installed on the guide rail (2). The capacitive grating sensor scale (6) takes the horizontal position where the end face of the transducer (5) on the fixed connecting rod (3) is located as the zero scale reference plane; the upper end of the movable connecting rod (4) is installed on the capacitive grating sensor scale (6) through a slider, and a capacitive grating sensor reader (7) is fixedly connected to the slider; when the end faces of the two transducers (5) are made to fit by moving the movable connecting rod (4), the reading of the capacitive grating sensor reader (7) is zero.

2. The device for precisely calibrating the delay time of an acoustic wave detector system according to claim 1, wherein: The capacitive grating sensor reader (7) is also fastened to the capacitive grating sensor scale (6) by a knob bolt (8).

3. A device for accurately calibrating the delay time of an acoustic wave detector system according to claim 1, characterized in that: The displacement measurement accuracy of the capacitive grating sensor reader (7) is not less than ±0.02 mm.

4. A device for precisely calibrating the delay time of an acoustic wave detector system according to claim 1, characterized in that: The transducer (5) is installed facing each other on the fixed connecting rod (3) and the movable connecting rod (4) through an elastic buckle (9) that can accommodate transducers of different diameters.

5. A device for precisely calibrating the delay time of an acoustic detector system according to claim 1, characterized in that: The inner side of the anechoic water tank (1) is wrapped with anechoic sponge (10).

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