CN207779647U - A kind of monitoring device loosened for pipe screw joint - Google Patents
A kind of monitoring device loosened for pipe screw joint Download PDFInfo
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- CN207779647U CN207779647U CN201820185040.1U CN201820185040U CN207779647U CN 207779647 U CN207779647 U CN 207779647U CN 201820185040 U CN201820185040 U CN 201820185040U CN 207779647 U CN207779647 U CN 207779647U
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Abstract
The utility model discloses a kind of monitoring devices loosened for pipe screw joint, including two piezoceramic transducers, data collecting card and computer for analysis terminal, two piezoceramic transducers are fixed on the surface of nipple and screwed pipe in a manner of surface mount respectively, two piezoceramic transducers are connected by cable with the output end of data collecting card and input terminal respectively, data collecting card and computer for analysis terminal, computer for analysis terminal generates excitation electric signal using data collecting card, and the piezoceramic transducer by being used as driver is sent out, piezoceramic transducer as receiver receives signal, and computer for analysis terminal is passed to by data collecting card conversion, computer for analysis terminal judges that pipe screw joint loosens state according to signal intensity situation is received.The utility model greatly improves the safety of pipe screw thread connection, reduces security risk and operation risk, improves overall economic benefit, generates positive meaning.
Description
Technical field
The utility model is related to structural health monitoring technology fields, are related to a kind of threaded connection loosening monitoring, and in particular to
A kind of monitoring device loosened for pipe screw joint.
Background technology
Centering, guiding role are good when inner and outer pipe screw thread be combined with each other, and assembly, convenient disassembly can bear larger axial force
And torque, it is widely used in the connection of small-medium size pipe-line system.When pipe screw thread works, for a long time by various external loads and
Effect of vibration influences, if lacking timely and effectively repair and maintenance, pipe screw joint position often will produce loosening and close to its
Envelope property causes larger destruction, therefore the loosening leakage problem for how solving pipe screw joint in the pipeline of seal request is long-term
Since it is of interest by people always.
Piezoelectric ceramics (Lead Zirconate Titanate, PZT) is with its distinctive sensing and actuator function and as close
One of the intellectual material studied and applied extensively in fields such as aerospace, the energy, machinery, building structure over year.It is because having
Response is fast, wide frequency range, easily cut, lower-price characteristic and that there is huge applications in terms of engineering structure monitoring is latent
Power.
Utility model content
The technical problems to be solved in the utility model is that the blank in monitoring field is loosened for pipe screw joint, proposes one
Kind loosens the monitoring device of disease for pipe screw thread, and accurate monitoring in real time can be carried out to the loosening of pipe screw joint and is known
Not.
In order to solve the above technical problems, technical solution used by the utility model is：
A kind of monitoring device loosened for pipe screw joint, it is characterised in that：Including two piezoceramic transducers, numbers
According to capture card and computer for analysis terminal, two piezoceramic transducers be fixed in a manner of surface mount respectively nipple and
The surface of screwed pipe, the piezoceramic transducer as driver are connected by cable with the output end of data collecting card, as
The piezoceramic transducer of receiver is connected by cable with the input terminal of data collecting card, and data collecting card is whole with computer for analysis
End, the computer for analysis terminal generate excitation electric signal using data collecting card, and excitation electric signal drives piezoceramic transducer
Mechanical oscillation are generated, form piezoelectric stress wave in pipe screw thread connection, and propagate along duct orientation, the piezoelectricity as receiver is made pottery
Porcelain sensor receives piezoelectric stress wave signal, and passes to computer for analysis terminal by data collecting card conversion, and computer for analysis is whole
End judges that pipe screw joint loosens state according to signal intensity situation is received.
As an improvement, uniformly smearing the epoxy resin with waterproof insulation function on piezoceramic transducer surface.
As an improvement, the data collecting card is NI data acquisition cards, NI data acquisition cards are by BNC cables respectively with two
A piezoceramic transducer is connected.
As an improvement, the NI data acquisition cards are connected by USB cable with computer for analysis terminal.
The beneficial effects of the utility model are for piezoceramic transducer technology to be applied to the work shape of pipe screw joint
The monitoring and identification of state (or loosening disease), definite principle, of low cost, operation is simple, identification is accurate, and pipe may be implemented
The long-term on-line monitoring of thread seal working condition and identification loosen the generation of leakage disease, drop for reducing pipe screw joint
The monitoring of low entire pipe-line system and operation expense, science is judged and the military service safety and remaining life of prediction pipe screw thread,
The safe and efficient operating for ensureing entire pipe screw thread system engineering, safeguards the security of the lives and property of numerous people, will generate actively
Meaning.
In addition the utility model is not necessarily to carry out specific customization to pipe screw joint to be monitored, only senses piezoelectric ceramics
Device is fixed on by bonding method on existing pipe screw joint, convenient and efficient, and use cost is cheap.
Description of the drawings
Attached drawing 1 is the pipe screw thread connection and piezoceramic transducer arrangement schematic diagram of the utility model.
Attached drawing 2 is that the pipe screw thread of the utility model loosens status monitoring schematic diagram.
Attached drawing 3 is that pipe screw thread is connected to thread contact area reduction contrast schematic diagram under sealing and loosening state；
Wherein Fig. 3 a are that pipe screw thread connects sealing state schematic diagram, and Fig. 3 b are that pipe screw thread connects schematic diagram under loosening state.
Attached drawing 4 is two piezoceramic transducer relative position change schematic diagrams under pipe thread seal and loosening state.
In figure：1- screwed pipes, 2- nipples, 3- piezoceramic transducers, 4- piezoceramic transducers, 5-BNC cables,
6-NI data acquisition cards, 7-USB cables, 8- computer for analysis terminals.
Specific implementation mode
Specific description is done to the embodiment of the utility model with reference to the accompanying drawings and examples：
Two screwed pipes 1 carry out pipe screw thread connection by nipple 2, take the mode of surface mount that will be used as later and drive
The piezoceramic transducer 3 of dynamic device is fixed on the surface of nipple 2, will be fixed as the piezoceramic transducer 4 of receiver
In the surface of one of pipe screw thread 1, epoxy resin is uniformly smeared on two piezoceramic transducers 3,4 surfaces, carries out waterproof
Insulation processing；
Two piezoceramic transducers 3,4 are connected to NI data acquisition cards 6, NI signal acquisitions by BNC cables 5 respectively
Card 6 is connected by USB cable 7 with computer for analysis terminal 8；
Computer for analysis terminal 8 controls the sine sweep excitation that NI data acquisition cards 6 generate certain frequency range by USB cable 7
Electric signal, and exported by 6 output end of NI data acquisition cards, it is transferred on piezoceramic transducer 3 through BNC cables 5, excitation electricity
Signal drives piezoceramic transducer 3 to generate mechanical oscillation, forms piezoelectric stress wave in pipe screw thread connection, and along duct orientation
It propagates；Then, piezoceramic transducer 4 receive connected by pipe screw thread transmit come piezoelectric stress wave signal, and converted
For electric signal, it is transferred to 6 input terminal of NI data acquisition cards through BNC cables 5, NI data acquisition cards 6 are defeated by piezoceramic transducer 4
The electric signal gone out is converted into digital signal, is transferred to computer for analysis terminal 8 by USB cable 7 later；
Under the normal seal operation state of the pipe screw thread defined in computer analysis system, the measured piezoelectricity as receiver
Ceramic sensor element 4 receives signal as reference signal, identification feature parameter reference value is built, later by monitoring different times pipe
It is threadedly coupled the identification feature parameter of measuring signal, by identification feature parameter and the comparative analysis of identification feature parameter reference value and is counted
It calculates and loosens judging quota, the variation by monitoring judging quota obtains the sealing situation of pipe screw joint.Defined loosening is commented
Sentence that index is bigger, then shows that the more normal sealing state deviation of working condition that measured tube is threadedly coupled is bigger.
For example, the energy value for setting the reception signal of piezoceramic transducer 4 can be expressed as E
Wherein, tsAnd tfTable is divided to indicate to receive the initial time and finish time, y (t) and f of signalsIt indicates to receive letter respectively
Number dis-crete sample values and sample frequency.
In this case, the loosening judging quota of pipe screw thread is to receive the relative change rate R of signal energy value, by following formula
It calculates：
Wherein, EtIndicate the signal energy value of structure actual measurement, E0Indicate the signal energy value under structural health sealing state,
As a reference value.Signal energy value E in above formula (2) can also be by wavelet-packet energy value, structure partial resonant frequency come generation
It replaces.
The small echo packet node coefficient r of signal is received for piezoelectric transducer, loosening judging quota can also be by small nodal point
The variation relative mean square deviation (root mean square deviation, RMSD) of coefficient r is calculated：
Wherein, riIndicate i-th of small echo packet node coefficient of structure measured signal, ri 0It indicates under structural health sealing state
I-th of small echo packet node coefficient of test signal, N indicate the number of small echo packet node coefficient.Wavelet packet section in its formula (3)
Dot factor r can also be replaced with signal fitting regression coefficient, factorial analysis coefficient.
The basic principle of the utility model is that two screwed pipes 1 carry out pipe screw thread connection by nipple 2, when pipe spiral shell
When line occurs to loosen leakage, the thread contact area of screwed pipe 1 and nipple 2 can change correspondingly, and loosen more serious, screw thread
The piezoelectric stress wave that contact area changes the bigger generation of piezoceramic transducer 3 as driver compared to sealing state swashs
It is bigger by pipe screw thread connection transmission decaying or variation to encourage signal, at the same time, the piezoceramic transducer 4 as receiver
The stress wave signal variation of reception is bigger, is by monitoring the piezoelectric stress wave signal intensity that piezoceramic transducer 4 receives
Pipe screw thread can be monitored and even loosen situation, in addition, the loosening of pipe screw thread is also frequently accompanied by screwed pipe 1 and phase occurs for nipple 2
To torsion.Therefore, by monitor and recognize because pipe screw thread loosen caused by screwed pipe 1 and nipple 2 relative position and spiral shell
The change of line contact area, you can identify the generation that pipe screw thread loosens, while to a certain extent, assessment loosens serious
Degree.
Here brief theory deduction is provided, as the above analysis, the loosening of pipe screw thread can cause screwed pipe 1 and screw thread
The thread contact area and relative position of connector 2 change, therefore provide brief theory respectively from these two aspects here and push away
It leads.
(1) pipe screw thread contact area caused by loosening changes
As shown in figure 3, when pipe screw thread loosens, it is assumed that 2 holding position of nipple is fixed, and screwed pipe 1 is along pine
Twist dynamic direction (it is assumed that counterclockwise) (such as Fig. 1), at this time the thread contact face of screwed pipe 1 and nipple 2
Product reduces therewith.For pipe screw thread, it is assumed that screwed pipe 1 counterclockwise often rotates one week, the contact area with nipple 2
Reduce Δ S0, this value is determined when pipe screw thread is dispatched from the factory, only with the geometric parameter of pipe screw thread in relation to (diameter of thread, is led at angle of thread
Journey etc.).
It is assumed that when pipe screw thread loosens, the torsion of θ counterclockwise occurs for screwed pipe 1, and the utility model only considers to loosen hair
The monitoring at raw initial stage, therefore ranging from 0 ＜ θ≤π of torsion angle.Then under such loosening state, pipe screw thread contact area knots modification
Δ S can be expressed as：
This formula can be expressed as：
Δ S ∝ θ (0 ＜ θ≤π) formula (5)
I.e. when pipe screw thread loosens, thread contact area change amount and the screwed pipe 1 of screwed pipe 1 and nipple 2
It is directly proportional along the corner for loosening direction twisting.
(2) pipe screw thread relative position caused by loosening changes
According to the utility model specific implementation method of above-mentioned introduction, in pressure of 1 surface mount of screwed pipe as receiver
Electroceramics sensor 4, in piezoceramic transducer 3 of 2 surface mount of nipple as driver.In pipe thread seal state
Under, two sensors 3 and 4 are on the same line along 1 length direction of screwed pipe, as shown in figure 4, and its initial phase to away from
From for L0.When pipe screw thread loosens, i.e., screwed pipe 1 rotates θ in the counterclockwise direction, at this time 3 position of piezoceramic transducer
It remains unchanged, and piezoceramic transducer 4 is rotated as the angles θ occur together for screwed pipe 1, final position is as shown in Figure 4.
Assuming that screwed pipe 1 often rotates one week in the counterclockwise direction, it is Δ that threadingly 1 length direction of pipe back-outs length outward
l0, this value is determined when pipe screw thread is dispatched from the factory, equally only with the geometric parameter of pipe screw thread in relation to (diameter of thread, angle of thread, helical pitch
Deng).Then when screwed pipe 1 rotates counterclockwise θ, it is Δ l that screwed pipe 1 back-outs length outward along its length, can be expressed as：
At the same time, with the rotation of screwed pipe 1, piezoceramic transducer 4 equally occurs along 1 circumferential direction of screwed pipe
Position change.Assuming that the radius of screwed pipe 1 is R, then when it rotates counterclockwise θ, threadingly pipe 1 of piezoceramic transducer 4
The position change amount of circumferential direction is θ R.As shown in figure 4, phase of two piezoceramic transducers 3,4 under loosening state at this time
The L that adjusts the distance can be expressed as：
Therefore, when pipe screw thread loosens, the relative position knots modification Δ L of two piezoceramic transducers 3,4 can be with
It is expressed as：
Above-mentioned formula (8) can also be expressed as：
Δ L ∝ θ (0 ＜ θ≤π) formula (9)
I.e. when pipe screw thread loosens, it is pasted onto the piezoceramic transducer 3 on 2 surface of nipple and is pasted onto screw thread
The relative position knots modification of the piezoceramic transducer 4 on 1 surface of pipe is positively correlated with screwed pipe 1 along the corner for loosening direction twisting
Relationship.
In conclusion when pipe screw thread loosens, the thread contact area of screwed pipe 1 and nipple 2 reduces therewith,
The relative position of two piezoceramic transducers 3,4 can also increase therewith simultaneously.And the piezoelectricity generated by piezoceramic transducer
Stress wave signal propagation law in the structure is it is found that receive the energy attenuation degree of signal with interstructural contact area at anti-
Than contact area is bigger, and stress wave is decayed smaller after being propagated by contact surface, that is, the energy received is bigger, conversely, contact surface
Product reduces, then the energy received also decreases.Meanwhile signal receives the relative distance of position and signal source also direct relation
To the energy attenuation degree for receiving signal, receiver is closer from signal source, then the energy received is bigger, on the contrary then smaller.Cause
This, by the attenuation degree for monitoring piezoelectric stress wave signal energy transmission in pipe screw thread connection, you can indirectly reflect spiral shell
Line pipe 1 and the thread contact area of nipple 2 and the situation of change of relative position.When unchanged, then show that pipe screw thread is close
Envelope is good, and non-loosening leakage occurs, and otherwise then shows that loosening occurs in pipe screw thread, sealing state is connected to pipe screw thread to realize
Monitoring and examination.The utility model proposes Method And Principle is simple, operation is easy, loosenings small to pipe screw thread, which changes, can also do
To accurate monitoring in real time and identification.
When the utility model is connected to loosening using pipe screw thread and occurs, relative position between screwed pipe and nipple and
Thread contact area changes, meanwhile, piezoelectric stress wave signal passes through the energy after practical contact surface during structure-borne
Amount attenuation degree is inversely proportional with contact area, the relationship directly proportional to the relative distance of receiver and signal source, by comparing real
Border receives the relative size of the energy and reference value under pipe thread seal state of signal, you can simply and efficiently realizes pipe screw thread
The monitoring and identification of sealing state reduce security risk and operation risk, improve total for improving the safety of pipe screw thread connection
Body economic benefit will generate positive meaning.
Claims (4)
1. a kind of monitoring device loosened for pipe screw joint, it is characterised in that：Including two piezoceramic transducers, data
Capture card and computer for analysis terminal, two piezoceramic transducers are fixed on nipple and spiral shell in a manner of surface mount respectively
The surface of line pipe, the piezoceramic transducer as driver are connected by cable with the output end of data collecting card, as connecing
The piezoceramic transducer for receiving device is connected by cable with the input terminal of data collecting card, and data collecting card is whole with computer for analysis
End, the computer for analysis terminal generate excitation electric signal using data collecting card, and excitation electric signal drives piezoceramic transducer
Mechanical oscillation are generated, form piezoelectric stress wave in pipe screw thread connection, and propagate along duct orientation, the piezoelectricity as receiver is made pottery
Porcelain sensor receives piezoelectric stress wave signal, and passes to computer for analysis terminal by data collecting card conversion, and computer for analysis is whole
End judges that pipe screw joint loosens state according to signal intensity situation is received.
2. monitoring device as described in claim 1, it is characterised in that：It uniformly smears to have on piezoceramic transducer surface and prevent
The epoxy resin of water insulation function.
3. monitoring device as described in claim 1, it is characterised in that：The data collecting card is NI data acquisition cards, NI letters
Number capture card is connected with two piezoceramic transducers respectively by BNC cables.
4. monitoring device as claimed in claim 3, it is characterised in that：The NI data acquisition cards pass through USB cable and computer
Analysing terminal is connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820185040.1U CN207779647U (en) | 2018-02-02 | 2018-02-02 | A kind of monitoring device loosened for pipe screw joint |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820185040.1U CN207779647U (en) | 2018-02-02 | 2018-02-02 | A kind of monitoring device loosened for pipe screw joint |
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| Publication Number | Publication Date |
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| CN207779647U true CN207779647U (en) | 2018-08-28 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109696282A (en) * | 2019-01-22 | 2019-04-30 | 中国海洋石油集团有限公司 | Deep water process facility acoustic emission detection system |
| CN111751040A (en) * | 2020-05-15 | 2020-10-09 | 国网浙江省电力有限公司台州供电公司 | Electric power iron tower bolt looseness detection system and method based on unmanned aerial vehicle image |
-
2018
- 2018-02-02 CN CN201820185040.1U patent/CN207779647U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109696282A (en) * | 2019-01-22 | 2019-04-30 | 中国海洋石油集团有限公司 | Deep water process facility acoustic emission detection system |
| CN111751040A (en) * | 2020-05-15 | 2020-10-09 | 国网浙江省电力有限公司台州供电公司 | Electric power iron tower bolt looseness detection system and method based on unmanned aerial vehicle image |
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