阅读说明：本技术 一种增强式低压检测系统及其检测方法 (Enhanced low-voltage detection system and detection method thereof ) 是由 乔新勇 刘艳斌 靳莹 张小明 杨浩 于 2020-06-22 设计创作，主要内容包括：本发明公开了一种增强式低压检测系统,包括：基座,其为U形结构,并包括依次连续设置的：第一部、第二部和第三部；两个固定机构,其分别对称设置在所述第一部和所述第三部的外表面上；两个测量机构,其分别对称匹配设置在所述固定机构上。通过两个对称设置的压力测试单元对管道不同位置进行压力测试,测试方便,成功率高。本发明还提供一种增强式低压检测系统的检测方法。(The invention discloses an enhanced low-voltage detection system, which comprises: the base, it is the U-shaped structure to including setting up in proper order in succession: a first portion, a second portion and a third portion; two fixing mechanisms symmetrically arranged on the outer surfaces of the first portion and the third portion respectively; and the two measuring mechanisms are respectively symmetrically arranged on the fixing mechanism in a matching manner. The pressure testing units which are symmetrically arranged are used for testing the pressure of different positions of the pipeline, so that the testing is convenient, and the success rate is high. The invention also provides a detection method of the enhanced low-voltage detection system.)

1. An enhanced low pressure detection system, comprising:

the base, it is the U-shaped structure to including setting up in proper order in succession: a first portion, a second portion and a third portion;

two fixing mechanisms symmetrically arranged on the outer surfaces of the first portion and the third portion respectively;

and the two measuring mechanisms are correspondingly matched and arranged on the fixing mechanism respectively.

2. The enhanced low pressure detection system of claim 1, wherein the first portion and the third portion are identical in structure and are disposed parallel to each other.

3. The enhanced low pressure detection system of claim 2, wherein the second portion is disposed perpendicular to the first portion and the third portion.

4. The enhanced low pressure detection system of claim 3, wherein the first, second, and third portions are all cuboid structures.

5. The enhanced low pressure detection system of claim 4, wherein the measurement mechanism is a pressure sensor.

6. The enhanced low pressure detection system of claim 5, wherein the securing mechanism comprises a set bolt and a set nut mated thereto.

7. A testing method of an enhanced low voltage testing system, which uses the enhanced low voltage testing system of any one of claims 1 to 6, and comprises:

installing two enhanced low-pressure detection systems at the inlet and the outlet of the pipeline to acquire pressure signals of different positions of the pipeline;

and after performing charge amplification, filtering and voltage amplification on the obtained pressure signal, performing analog-to-digital conversion and processing to obtain a pressure value at the measuring position.

8. The detection method of the enhanced low voltage detection system of claim 7, wherein the pressure signal is conditioned to an analog voltage and analog-to-digital converted after passing through a charge amplifier, an active filter and a voltage amplifier in sequence.

9. The detection method of the enhanced low-voltage detection system according to claim 8, wherein the analog voltage is 0-5 v.

10. The detection method of the enhanced low-voltage detection system as claimed in claim 9, wherein the analog-to-digital conversion employs an 80C196KD single chip microcomputer.

Technical Field

The invention relates to an enhanced low-voltage detection system and a detection method thereof, belonging to the field of pipeline fault detection.

Background

Actuating systems using liquids as working media are widely used in various engineering machines, vehicles, ships and aircrafts. In the devices, the hydraulic subsystem often performs work and control functions, and the hydraulic subsystem is in failure, which seriously influences the function exertion of the devices; the petrochemical system using liquid as a working object is full of various pipelines, pumps and valves, and the system fails, so that the normal production is influenced, huge economic loss is caused, and major accidents are often caused. Condition monitoring and fault diagnosis for these systems is an important responsibility of engineering technicians and is the subject of research by technologists. The inspection or on-line test of the systems and the components thereof is a target for engineering industry.

There have been a number of successful paradigms for the non-disassembly detection of high voltage systems, while the non-disassembly detection of low voltage systems is a technical problem that has plagued the engineering community for many years. The technical key points are that the response parameter values of various elements of the low-voltage system to different working states are very small, the sensitivity of a common sensor system is low, and response signals are difficult to measure; even if some weak signals are acquired, they are mostly submerged in the ambient noise interference.

As is known, a non-disassembly test is a technique that can detect functional, structural or response parameters of a system under test without any disassembly or damage to the system under test and without affecting its normal operation. The parameters that characterize the operating state of a pressure system are pressure, flow and temperature, while the most common test parameters for pressure line, component condition monitoring and fault diagnosis are dynamic magnitudes of pressure and flow. Corresponding non-disassembly test techniques include an external clamp pressure test and an ultrasonic flow test. Although pressure and flow are important parameters for hydraulic systems, since a large number of hydraulic actuation systems operate using pressure as an indicator, condition monitoring and fault diagnosis of hydraulic systems using pressure as a test parameter is more direct and efficient than flow, and ultrasonic testing systems are relatively expensive. However, the existing external card pressure sensor system has the defects of low detection sensitivity and weak anti-interference capability, and is often ineffective in low-pressure and vibration environments.

Disclosure of Invention

The invention designs and develops an enhanced low-pressure detection system, which is convenient to test and high in success rate by carrying out pressure tests on different positions of a pipeline through two symmetrically arranged pressure test units.

The invention also designs and develops a detection method of the enhanced low-pressure detection system, which can monitor the dynamic pressure of the pipeline in real time, and has the advantages of high pressure detection resolution, large test range and good test effect.

The technical scheme provided by the invention is as follows:

an enhanced low pressure detection system comprising:

the base, it is the U-shaped structure to including setting up in proper order in succession: a first portion, a second portion and a third portion;

two fixing mechanisms symmetrically arranged on the outer surfaces of the first portion and the third portion respectively;

two measuring mechanisms respectively corresponding to

The matching is arranged on the fixing mechanism.

Preferably, the first and third portions are identical in structure and are arranged parallel to each other.

Preferably, the second portion is disposed perpendicular to the first portion and the third portion.

Preferably, the first portion, the second portion, and the third portion are each a rectangular parallelepiped structure.

Preferably, the measuring means is a pressure sensor.

Preferably, the fixing mechanism comprises a positioning bolt and a positioning nut matched with the positioning bolt.

A detection method of an enhanced low-pressure detection system is used, and comprises the following steps:

installing two enhanced low-pressure detection systems at the inlet and the outlet of the pipeline to acquire pressure signals of different positions of the pipeline;

and after performing charge amplification, filtering and voltage amplification on the obtained pressure signal, performing analog-to-digital conversion and processing to obtain a pressure value at the measuring position.

Preferably, the pressure signal is conditioned to an analog voltage after passing through a charge amplifier, an active filter and a voltage amplifier in sequence, and is subjected to analog-to-digital conversion.

Preferably, the analog voltage is 0 to 5 v.

Preferably, the analog-to-digital conversion adopts an 80C196KD singlechip.

The invention has the following beneficial effects: the enhanced low-pressure detection system provided by the invention is formed by oppositely mounting two pressure sensors. Two sensors with the same characteristics sense radial changes generated by dynamic excitation of the pressure of the pipeline with the same section; while sensing the opposite wall vibrations at the same section. The structure lays theoretical and technical foundation for eliminating vibration interference and improving detection sensitivity.

Drawings

FIG. 1 is a front view of an enhanced low pressure detection system according to the present invention.

FIG. 2 is a side view of an enhanced low pressure detection system according to the present invention.

Fig. 3 is a schematic circuit diagram of the pressure regulating module.

Fig. 4 is a pressure measurement flow chart.

Fig. 5 is a pressure calibration curve.

FIG. 6 is a schematic diagram of the sensitivity of the present invention measured outside the tube without disassembly of the boost pressure.

FIG. 7 is a schematic diagram of the sensitivity of the voltage measurement without disassembly outside the tube according to the present invention.

Fig. 8 is a hardware connection diagram of the enhanced low-voltage signal processing system according to the present invention.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

As shown in fig. 1-8, the present invention provides an enhanced low voltage detection system comprising: the pipeline 100, the base 210, the fixing mechanism 220, the pressure testing mechanism 230 and the lead-out wires 240.

The base 210 has an opening on one side, is closed on one side, has a U-shaped structure as a whole, and includes a first portion 210a, a second portion 210b, and a third portion 210c, which are sequentially and continuously disposed, wherein the first portion 210a and the second portion 210b have the same structure and are disposed in parallel with each other, and the third portion 210c is disposed between the first portion 210a and the second portion 210b and is disposed perpendicular to the first portion 210a and the second portion 210 b.

In the present invention, it is preferable that the first portion 210a, the second portion 210b, and the third portion 210c are each a rectangular parallelepiped structure.

The two fixing mechanisms 220 are respectively arranged on the first portion 210a and the third portion 210c and are oppositely arranged, the central lines of the two fixing mechanisms 220 are located on the same straight line, each fixing mechanism 220 comprises a positioning bolt and a positioning nut matched with the positioning bolt, one end of each positioning bolt penetrates through and is fixed on the first portion 210a or the third portion 210c, the other end of each positioning bolt is connected with the corresponding positioning nut in a matching mode, and the two pressure measuring mechanisms 230 are respectively arranged on the corresponding positioning nuts.

In the present invention, it is preferable that the two measuring units 230 are pressure sensors.

In the invention, two pressure sensors are oppositely arranged, and two sensors with the same characteristics sense radial change generated by dynamic excitation of the pressure of a pipeline with the same section; while sensing the opposite wall vibrations at the same section. The structure lays a foundation for eliminating vibration interference and improving detection sensitivity.

Because all pressure pipelines consider the safety factor in the design, the pipe wall change caused by the pressure change of the metal pipeline is very weak. The sensitivity of the sensor system can be doubled. As to the pressure sensitive element to which principle is applied, it should be determined according to the purpose of detection. Generally speaking, a piezoelectric sensitive element has high sensitivity and good dynamic characteristic, but because a commonly used matched instrument is a charge amplifier, the static characteristic is poor, and the static pressure cannot be tested; the semiconductor piezoresistive pressure sensor is high in sensitivity and capable of testing static pressure, but the temperature characteristic is poor, the temperature is large, the size is difficult to manufacture, and the application of the semiconductor piezoresistive pressure sensor in the pressure test without disassembly of a small pipeline is limited; the metal strain gauge type pressure sensor has low sensitivity and large volume although the temperature characteristic is good, and also limits the application of the metal strain gauge type pressure sensor in the pressure test without disassembling a small pipeline. The piezoelectric pressure sensor system is applied, and a good effect is obtained on testing the dynamic pressure.

For the design of the non-disassembled low pressure detection system, the design of the base or fixture and the auxiliary devices needs to consider the following:

(1) the design of the base and the clamp has enough strength and rigidity, and position movement and nonlinear deformation cannot be generated in the test process;

(2) the design of the base and the clamp needs a good centering technology to ensure that the pressure sensor is not only symmetrical, but also has good centering property, and the central line of the pressure sensor is required to be coincided with the diameter of the pipeline;

(3) the design of the base and the clamp needs a certain radial adjusting range and is suitable for the test requirements of pipelines with different calibers.

The invention also provides a detection method of the enhanced low-voltage detection system, which comprises the following steps:

installing two enhanced low-pressure detection systems at the inlet and the outlet of the pipeline to acquire pressure signals of different positions of the pipeline;

and after performing charge amplification, filtering and voltage amplification on the obtained pressure signal, performing analog-to-digital conversion and processing to obtain a pressure value at the measuring position.

The pressure signal is conditioned to analog voltage after sequentially passing through a charge amplifier, an active filter and a voltage amplifier, and analog-to-digital conversion is carried out;

in the present invention, it is preferable that the analog voltage is 0 to +5 v.

In the invention, as a preferable choice, the digital-to-analog converter is an 80C196KD single chip microcomputer.

The signal processing scheme and techniques of the non-disassembly pressure testing system may be designed according to functional requirements. For a single pressure test, only five functional modules of amplification, filtering, an adder, display and a power supply need to be designed. Two paths of signals sensed by the sensor system can eliminate vibration interference and display the transient pressure value through the processing of the functional module. However, to monitor the state of the system and the elements and diagnose the faults, a large amount of data needs to be collected, the technical state of the system needs to be evaluated and diagnosed, and history records are kept, so that the signal processing technology is high in requirement. In addition to the complexity of the hardware system, a corresponding software system must be designed according to the required functionality.

The system takes a single chip as a core and comprises:

(1) let x₁(t)，x₂(t) pressure signals, y, respectively, sensed by the sensor pairs₁(t)，y₂(t) is the vibration signal that the sensor pair felt, because the radial variation of pipeline same cross-section department is the same, and the vibration magnitude is the same, and the sensitivity of sensor pair is the same and reverse installation, so have:

x₁(t)＝x₂(t),y₁(t)＝-y₂(t)

two paths of signals are added:

z(t)＝x₁(t)+x₂(t)+y₁(t)+y₂(t)＝2x₁(t)

the signal processing method obviously improves the signal-to-noise ratio of the detection signal and brings great convenience and benefits for further signal analysis.

(2) The pressure conditioning module needs a +/-12V power supply to supply power and outputs pressure signals with a full range of +/-10V, each module integrates four paths of charge amplifiers, the passband is 0.1 Hz-23 Hz, and the output signals are 1 and 2 channels and signals and 3 and 4 channels and signals. The circuit structure of the pressure conditioning module is shown in fig. 3.

(3) For condition monitoring of the components of the hydraulic system, it is necessary to simultaneously measure the inlet and outlet pressures of the selected component in the operating state, for which two sets of four pressure sensors are required. The pressure signal is conditioned to 0- +5V analog voltage after passing through a charge amplifier, an active filter and a voltage amplifier, and is sent to A/D of 80C196KD for analog-to-digital conversion, and the pressure measurement flow is shown in figure 4.

(4) The voltage amplifier is provided with two stages of numerical control adjustment (to adapt to different sensitivities required by the elastic pipeline and the rigid pipeline), and the amplification factor is controlled by a numerical control analog switch CD 4066.

(5) The active filter uses MAX291 (single-channel low-pass filter, Butterworth type, 8-order, switch capacitor type, cut-off frequency 0.1Hz-25Hz, clock ratio 100, clock and capacitor control cut-off frequency), and the cut-off frequency of each active filter needs to be synchronously adjusted to ensure that the phase of each signal is synchronous.

(6) Every two paths of the 4 paths of dynamic pressure signals form a group, and the signals pass through a sum circuit and a difference circuit to finally generate 8 paths of signals of A, B, C, D, A + B, A-B, C + D, C-D. The A-B, C-D signals are used to fine tune the attenuation of A, B and C, D, respectively, to ensure that A + B, C + D suppresses the in-phase vibration signal to the maximum extent when the steady-state A-B, C-D output is 0. This adjustment is done automatically by the system.

(7) The pressure signals generated by the four piezoelectric crystal force sensors are directly connected to the analog input end of the A/D converter through eight analog signals generated by the signal conditioning circuit, and the electrical connection relationship is shown in table 1. The voltage reference Vref is generated by a precision reference source LM 336.

TABLE 1 Electrical connection relationships