A vibrating wire sensor for contactless cable joints

Abstract

The present invention discloses a vibrating string sensor for a non-contact cable connector, comprising a housing, a pressure-bearing membrane arranged at one end of the housing, a vibrating string, a clamping device for clamping the vibrating string, a first electromagnetic induction coil, a signal transmitting device, a signal receiving device and a cable connector, wherein the signal receiving device is arranged outside the housing and connected to the cable connector, the signal transmitting device is connected to the first electromagnetic induction coil, the first electromagnetic induction coil is used to excite the vibrating string to oscillate, and is used to obtain an oscillation frequency signal, the signal transmitting device is used to receive and send the oscillation frequency signal obtained by the first electromagnetic induction coil, and the signal receiving device is used to receive the oscillation frequency signal transmitted by the signal transmitting device. The process of driving the steel string to vibrate and detecting its free oscillation frequency is non-contactly connected to an external matching instrument, and the core component is physically isolated so that its working environment has no water vapor exchange with the outside world, ensuring that the working environment of the core component is in a dry and constant state.

Description

Technical Field

[0001] The invention relates to civil engineering detection, in particular to a vibrating wire sensor for a non-contact cable joint. Background Art

[0002] The in-situ monitoring instruments for geotechnical engineering are deeply buried in the rock and soil. They are used to measure physical quantities such as displacement, stress, and strain. Most of them are vibrating string sensors. The steel string is the core component and is encapsulated in a stainless steel carrier. The measurement is carried out by using the correlation between the free oscillation frequency of the steel string and the tension it is subjected to. The steel string is driven to oscillate by an external oscillating current, and the free oscillation frequency of the steel string is detected to determine the stress state of the steel string, thereby reflecting the displacement of the steel string carrier. The process of driving the steel string to vibrate and detecting its free oscillation frequency requires the connection of external supporting instruments. The wired connection has the problem of water vapor on site slowly penetrating into the core component cavity from the cable interface or the damaged port along the cable core, which will cause changes in the working environment of the core component and affect the detection accuracy and instrument life. This is a common problem of various vibrating string sensors at home and abroad. Summary of the invention

[0003] Purpose of the invention: In view of the above disadvantages, the present invention provides a vibrating wire sensor for a non-contact cable joint that prevents the sealing failure of the cable interface.

[0004] Technical solution: To solve the above problems, the present invention adopts a vibrating string sensor with a non-contact cable connector, including a shell, a pressure-bearing membrane arranged at one end of the shell, a vibrating string, a clamping device for clamping the vibrating string, a first electromagnetic induction coil, a signal transmitting device, a signal receiving device and a cable connector, wherein the vibrating string, the clamping device, the first electromagnetic induction coil and the signal transmitting device are all encapsulated in the shell, the signal receiving device is arranged outside the shell and connected to the cable connector, the signal transmitting device is connected to the first electromagnetic induction coil, the first electromagnetic induction coil is used to excite the vibrating string to oscillate, and is used to obtain the oscillation frequency signal of the vibrating string, the signal transmitting device is used to power the first electromagnetic induction coil, and is used to receive and send the oscillation frequency signal obtained by the first electromagnetic induction coil, and the signal receiving device is used to power the signal transmitting device, and is used to receive the oscillation frequency signal transmitted by the signal transmitting device.

[0005] Furthermore, the signal transmitting device includes a first matching circuit and a second electromagnetic induction coil, the first electromagnetic induction coil and the second induction coil are connected through the first matching circuit, the signal receiving device includes a second matching circuit, a third electromagnetic induction coil and a receiving device housing, a cable connector is provided at one end of the receiving device housing, and the third electromagnetic induction coil is connected through the second matching circuit and the cable connector; the receiving device housing is connected to the housing through a connecting piece, and the second electromagnetic induction coil and the third electromagnetic induction coil are close to each other, and power and signal transmission are achieved between the second electromagnetic induction coil and the third electromagnetic induction coil through electromagnetic conversion.

[0006] Furthermore, the connecting piece is a sleeve, and positioning pins are provided at both ends of the sleeve. The housing and the receiving device housing are close to each other in the sleeve and are positioned with each other through the positioning pins.

[0007] Beneficial effect: Compared with the prior art, the significant advantage of the present invention is that the oscillation frequency signal obtained in the shell is received by the signal receiving device, the process of driving the steel string to vibrate and detecting its free oscillation frequency is non-contactly connected with the external supporting instrument, avoiding direct connection between the cable and the core components inside the sensor, and physically isolating the core components so that there is no water vapor exchange between their working environment and the outside world, ensuring that the working environment of the core components is in a dry and constant state, and solving the problem of water vapor affecting the detection accuracy and life of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Shown is a schematic diagram of the structure of the vibrating wire sensor in the present invention;

[0009] Figure 2 Shown is a first matching circuit diagram in the present invention;

[0010] Figure 3 Shown is a second matching circuit diagram in the present invention. DETAILED DESCRIPTION

[0011] like Figure 1 As shown, a vibrating string sensor for a non-contact cable connector in this embodiment includes a housing 1, a pressure-bearing membrane 2 arranged at one end of the housing, a vibrating string 3, a clamping device 4 for clamping the vibrating string, a first electromagnetic induction coil 5, a signal transmitting device 6, a signal receiving device 7 and a cable connector 8. The vibrating string 3, the clamping device 4, the first electromagnetic induction coil 5 and the signal transmitting device 6 are all packaged in the housing 1, which can effectively prevent water vapor from affecting the vibrating string 3. The vibrating string 3 is a steel string. The signal receiving device 7 is arranged outside the housing 1 and connected to the cable connector 8. The vibrating string and the clamping device are arranged in a conventional manner. Figure 1 The diagram is for schematic illustration only.

[0012] The signal transmitting device 6 is connected to the first electromagnetic induction coil 5. The signal transmitting device 6 includes a first matching circuit 61 and a second electromagnetic induction coil 62. The first electromagnetic induction coil 5 and the second induction coil 62 are connected through the first matching circuit 61. The first electromagnetic induction coil 5 is a magnetic tank wound with a coil. The first electromagnetic induction coil 5 is used to excite the vibrating string 3 to oscillate and to obtain the oscillation frequency signal of the vibrating string 3. The signal transmitting device 6 is used to power the first electromagnetic induction coil 5 and to receive and send the oscillation frequency signal obtained by the first electromagnetic induction coil 5. The circuit diagram of the first matching circuit is shown in FIG. Figure 2 shown.

[0013] The signal receiving device 7 includes a second matching circuit 71, a third electromagnetic induction coil 72 and a receiving device housing 73. The third electromagnetic induction coil 72 is used to supply power to the second electromagnetic induction coil 62 and to receive the oscillation frequency signal emitted by the second electromagnetic induction coil 62. A cable connector 8 is provided at one end of the receiving device housing 73. The third electromagnetic induction coil 72 is connected to the cable connector 8 via the second matching circuit 71. The circuit diagram of the second matching circuit is shown in FIG. Figure 3 shown.

[0014] The receiving device housing 73 is connected to the housing 1 through a connector 9, which is a stainless steel sleeve with positioning pins 91 at both ends. The housing 1 and the receiving device housing 73 are close to each other in the sleeve and are positioned with each other through the positioning pins 91. The second electromagnetic induction coil 62 and the third electromagnetic induction coil 72 are close to each other, and electromagnetic conversion is used to realize power and signal transmission between the second electromagnetic induction coil 62 and the third electromagnetic induction coil 72.

[0015] The cable connector 8 is connected to the cable, and power is input from the cable. Under the drive of the second matching circuit, an excitation signal is generated. The excitation signal is transmitted to the first electromagnetic induction coil 5 through the magnetic tank coupling for excitation. The vibrating string 3 vibrates under the excitation. At the same time, the first electromagnetic induction coil 5 is switched to the monitoring state, monitoring the vibration frequency signal of the vibrating string 3, and sending the vibration frequency signal through the magnetic tank coupling.

Claims

1. A vibrating wire sensor for a non-contact cable connector, characterized in that: The invention comprises a housing (1), a pressure-bearing membrane (2) arranged at one end of the housing (1), a vibrating string (3), a clamping device (4) for clamping the vibrating string, a first electromagnetic induction coil (5), a signal transmitting device (6), a signal receiving device (7) and a cable connector (8), wherein the vibrating string (3), the clamping device (4), the first electromagnetic induction coil (5) and the signal transmitting device (6) are all encapsulated in the housing, the signal receiving device (7) is arranged outside the housing and connected to the cable connector (8), the signal transmitting device (6) is connected to the first electromagnetic induction coil (5), the first electromagnetic induction coil (5) is used to excite the vibrating string (3) to oscillate and to obtain an oscillation frequency signal of the vibrating string (3), the signal transmitting device (6) is used to supply power to the first electromagnetic induction coil (5) and to receive and send the oscillation frequency signal obtained by the first electromagnetic induction coil (5), and the signal receiving device (7) is used to supply power to the signal transmitting device (6) and to receive the oscillation frequency signal transmitted by the signal transmitting device (6); The signal transmitting device (6) comprises a first matching circuit (61) and a second electromagnetic induction coil (62), the first electromagnetic induction coil (5) and the second electromagnetic induction coil (62) being connected via the first matching circuit (61), the signal receiving device (7) comprising a second matching circuit (71), a third electromagnetic induction coil (72) and a receiving device housing (73), one end of the receiving device housing (73) being provided with a cable connector (8), the third electromagnetic induction coil (72) being connected via the second matching circuit (71) and the cable connector (8); the receiving device housing (73) is connected to the housing via a connector (9), the second electromagnetic induction coil (62) and the third electromagnetic induction coil (72) being close to each other, and the second electromagnetic induction coil (62) and the third electromagnetic induction coil (72) realizing power and signal transmission via electromagnetic conversion.

2. The vibrating wire sensor according to claim 1, characterized in that The connecting member (9) is a sleeve, and positioning pins (91) are provided at both ends of the sleeve. The housing and the receiving device housing (73) are close to each other in the sleeve and are positioned relative to each other via the positioning pins (91).

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