CN1186628C - External adhesive composite wide band transducer - Google Patents
External adhesive composite wide band transducer Download PDFInfo
- Publication number
- CN1186628C CN1186628C CNB031126448A CN03112644A CN1186628C CN 1186628 C CN1186628 C CN 1186628C CN B031126448 A CNB031126448 A CN B031126448A CN 03112644 A CN03112644 A CN 03112644A CN 1186628 C CN1186628 C CN 1186628C
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- China
- Prior art keywords
- stack
- pedestal
- piezo crystals
- aluminium alloy
- hole
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- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Transducers For Ultrasonic Waves (AREA)
Abstract
The present invention discloses an external adhesive type composite broadband transducer which is a composite material broadband ultrasonic transducer used for the disastrous partial discharge fault diagnosis of power transformers(comprising 220KV, 500KV, 750KV and GIS systems) by multi-parameter monitor, which belongs to the technical field of an acoustic emission non-destructive detection technology. A shielding casing 10 is covered on a base 15 to form a fully enclosed whole, a through hole 151 is drilled in the center of the base 15, a sound transparent layer 1 is arranged at the bottom of the through hole 151, an aluminum alloy matching block 2 is fixed to the upper side of the sound transparent layer 1, the periphery of the aluminum alloy matching block 2 is connected with the bottom edge of the through hole 151 in the base 15, a piezoelectric crystal pile 3 is arranged on the upper side of the aluminum alloy matching block 2, the piezoelectric crystal pile 3 is provided with a sound absorbing block 4, two input ends 13, 14 of a preamplifier 11 are connected with a positive electrode and a negative electrode of the piezoelectric crystal pile 3, two output ends 6, 7 of the preamplifier 11 are connected with a socket 9, and a magnetic disc 5 is embedded into the bottom of the base 15.
Description
One, technical field
The present invention is a kind of compound substance wide band ultrasonic transducer that is used for the disastrous partial discharges fault diagnosis of multi-parameter monitoring power transformer (comprising 220KV, 500KV, 750KV and generalized information system).Belong to the acoustic emission technical field of nondestructive testing.
Two, background technology
Existing both at home and abroad monitoring Partial Discharge in Power Transformer with PZT (be lead zirconate titanate, Pb (Ti, Zr) O
3Solid solution is hereinafter to be referred as PZT) shortcoming of resonant mode transducer is: (1) because stack of piezo crystals adopts the solid electroceramics of PZT, PZT acoustic impedance height, and detects that medium (transformer oil) is serious to be lost, so transducer sending and receiving sensitivity is not high; (2) because PZT can only make 200KHz frequency range following (frequency range between the practical 200KHz to 1MHz is had any problem), so select frequency range to be restricted; (3) PZT transducer Q value is high, and detection waveform longer duration, repercussion are big, rising edge owes high and steep on foot, and not only influence detects resolution, and reduces and detect degree of accuracy; (4) the PZT stack of piezo crystals is the bidimensional vibrating mass, and the high frequency waveforms of detection is subjected to LOW FREQUENCY DISTORTION; (5) the PZT transducer is coupled on the solid dielectric longitudinal and transverse phase of wave is changed mutually, disturbed, and influences accuracy of detection and reliability.
The fault detect of conventional electric power transformer partial discharge has two kinds of modes: French Siemens adopted the formula transducer that shakes in (1) 2002 year, put in detection in the transformer but carry out probe; (2) most development testers also continue to use the detection of the steel casing outside.More than the two transducer all still adopt the brilliant heap of solid resonant mode PZT.
Three, summary of the invention
1, technical matters
Purpose of the present invention just provides the external labeling type broadband transducers of a kind of high sensitivity, low reactance-resistance ratio, short reverb.
2, technical scheme
A kind of external labeling type broadband transducers, by stack of piezo crystals, shells etc. are formed, it is characterized in that shielding cap and on pedestal, form a totally enclosed integral body, central authorities at pedestal are provided with a through hole, bottom at through hole is provided with sound transparent layer, on sound transparent layer, be fixed with the aluminium alloy match block, the periphery of aluminium alloy match block is connected with through hole base in the pedestal, on the aluminium alloy match block, be provided with stack of piezo crystals, on stack of piezo crystals, be provided with sound absorption block, two input ends of prime amplifier and stack of piezo crystals are just, negative electrode links to each other, two output terminals of prime amplifier are connected with socket, the outlet ground utmost point and shielding case separate connection have also embedded disk in the bottom of pedestal.Stack of piezo crystals 3 is composited by PZT and high molecular polymer two-phase, the piezoelectric pile front end is provided with sound transparent layer, the thickness of this sound transparent layer is 0.8mm, by softness is that the following silicon rubber of 40 degree is made, baseplane 0.3mm～the 0.8mm of pedestal is protruded in the bottom of this sound transparent layer, the specific acoustic impedance of aluminium alloy match block square is approximately equal to the product of steel plate specific acoustic impedance and stack of piezo crystals specific acoustic impedance, the thickness of aluminium alloy match block is approximately equal to the quarter-wave size of stack of piezo crystals resonance frequency, and the aluminium alloy match block is fixed on the through hole in the pedestal with silicon rubber vulcanization.Sound absorption block is combined into by tungsten powder and epoxy resin, the height of sound absorption block and equal diameters.Shielding case and pedestal are formed columniform screening can, and its overall height is 1/2～1/3 of a diameter, and accessory power outlet is arranged on the side of shielding case.Disk in base bottom was uniformly distributed on the same circumference by a plurality of the composition, and two magnetic poles of its disk (being S, the N utmost point) oppositely are provided with each other for adjacent.
3, technique effect
The external labeling type broadband transducers is than the solid transducer of conventional P ZT, and its work efficiency doubles, sensitivity doubles, passband broadening several times.This technology shows: the ultrasonic time waveform is high and steep on foot, and reverb shortens, thereby can distinguish a plurality of type local-discharge ultrasonic wave characteristic outlines on time domain.Be placed on the time domain failure message and created prerequisite for distinguishing disastrous office.
The characteristics of broadband transducers of the present invention are:
The first, acoustic coupling adopts the silicon rubber of softness 40 degree to substitute the hard oil coupling, makes simple and convenient user operation, and the condition of at every turn monitoring is close, can compare; The second, the sound that has improved from case shell steel plate to stack of piezo crystals is joined a condition, promptly add the aluminium alloy match block, (compound back receiving sensitivity is-196dB to guarantee doubling sensitivity, odb=1v/ μ Pa) and frequency span increase more than one times, compound back passband is wideer, and promptly the Q value reduces manyfold than solid PZT piezoelectric crystal; Three, volume little, in light weight, used 8 10mm nickel cobalt magnetic patch, magnetic chuck power big, soft silicon rubber enough is out of shape, and fills and leads up uneven surface, the clearance minimum between guard box shell steel plate and the broadband transducers improves sound transmission efficient; Four, 1-3 links compound compressional wave stack of piezo crystals with PZT pillar cycle (or non-periodic) arrangement skeleton, injects epoxy, satisfies: 8.9-10 * 10
6The specific acoustic impedance of PaS/m; d
33Be 345 * 10
-12C/N; Mechanical q-value is 10; Transverse electromechanical coupling factor K
P＜15%; Five, transducer stack of piezo crystals diameter 22mm, its resonance frequency is 500kHz, constitutes the flat region at 100kHZ to 300kHZ when making receiving sensor, this district receives working range for broadband mode, the only low 6dB of remolding sensitivity tuning-points.Six, epoxy tungsten powder sound absorption block satisfies: tungsten powder (200 order) is 30% with the volume ratio of epoxy, and acoustic impedance is 9.010
6PaS/m, tile height and equal diameters make acoustic transducer form the unidirectional reception of one dimension, and waveform is simple.
Four, description of drawings
Fig. 1 is the structural representation of external labeling type broadband transducers of the present invention.Sound transparent layer 1, aluminium alloy match block 2, stack of piezo crystals 3, sound absorption block 4, disk 5, amplifier out 6,7, grounded shield line 8, socket 9, shielding case 10, prime amplifier 11, gib screw 12, stack of piezo crystals contact conductor 13,14, pedestal 15, through hole 151 are wherein arranged.
Five, specific embodiments
In the external labeling type broadband transducers of the present invention: stack of piezo crystals 3 is composited by PZT and polymkeric substance two-phase 1-3 binding, and (specific acoustic impedance is about 8.9-1110
6PaS/m); Stack of piezo crystals tuning-points 500 kHz, and working frequency range low from tuning-points 100-300kHz; The stack of piezo crystals positive and negative electrode puts 11 before suspending and delivering to; Sound transparent layer 1 by silicon rubber vulcanization on the aluminium alloy match block, thickness 0.8mm (protrude base bottom surface 0.3mm); Aluminium alloy match block thickness is 6.3mm; Sound absorption block 4 is composited by tungsten powder and epoxy resin, acoustic impedance about 910
6PaS/m, this block height and equal diameters; Pedestal 15 and shielding case 10 are made up of light aluminum alloy.Nickel cobalt disk 5 is by diameter 10mm, totally 8 rings of thick 4mm is distributed on the pedestal outer shroud circumference, N-S is extremely adjacent oppositely to be provided with each other, constitute very strong suction with transformer sheet, the silicon rubber of sound transparent layer has 40 degree softnesses, protrude base bottom surface 0.3mm, showing slightly to steel plate, the height defective plays the effect of tamping that replenishes, air is caught up with light, guarantee that no solid oil coupling Ji closes high sound transmission path is still arranged under the condition, transducer is provided with the aluminium alloy match block behind sound transmitting rubber, match block is close to compound brilliant heap, and the rearmounted sound absorption block of brilliant heap constitutes stack of piezo crystals to the acoustic transmission optimal coupling condition between the transformer sheet three.The piezoelectric signal that stack of piezo crystals obtains amplifies 100 times by low-noise preamplifier, filtering passband: 100kHz-300kHz holds concurrently, cause socket by shielded cable, shielding case and pedestal are formed columniform screening can, its overall height is 1/2～1/3 of a diameter, socket independent grounding, accessory power outlet are arranged on the side of shielding case.
Claims (7)
1, a kind of external labeling type broadband transducers, by stack of piezo crystals, shielding case is formed, it is characterized in that shielding case (10) covers in totally enclosed integral body of the last composition of pedestal (15), central authorities at pedestal (15) are provided with a through hole (151), be provided with sound transparent layer (1) in the bottom of through hole (151), on sound transparent layer (1), be fixed with aluminium alloy match block (2), the periphery of aluminium alloy match block (2) is connected with through hole (151) base in the pedestal (15), on aluminium alloy match block (2), be provided with stack of piezo crystals (3), on stack of piezo crystals (3), be provided with sound absorption block (4), two input ends (13 of prime amplifier (11), 14) with stack of piezo crystals (3) just, negative electrode links to each other, just, negative electrode suspends with ground, two output terminals (6 of prime amplifier (11), 7) be connected with socket (9), also embedded disk (5) in the bottom of pedestal (15).
2, external labeling type broadband transducers according to claim 1 is characterized in that stack of piezo crystals (3) is composited by lead zirconate titanate and high molecular polymer two-phase.
3, external labeling type broadband transducers according to claim 1, the thickness that it is characterized in that sound transparent layer (1) is 0.8mm-2mm, by softness is that the following silicon rubber of 40 degree is made 0.3mm-0.8mm outside the baseplane of the bottom protrusion pedestal (15) of this sound transparent layer (1).
4, external labeling type broadband transducers according to claim 1, it is characterized in that the specific acoustic impedance of aluminium alloy match block (2) square is approximately equal to the product of steel plate specific acoustic impedance and stack of piezo crystals (3) specific acoustic impedance, the thickness of aluminium alloy match block (2) is approximately equal to the quarter-wave of stack of piezo crystals (3) resonance frequency, and aluminium alloy match block (2) is fixed on the through hole (151) in the pedestal (15) with the vulcanization of rubber.
5, external labeling type broadband transducers according to claim 1 is characterized in that sound absorption block (4) is combined into by tungsten powder and epoxy resin, the height and the equal diameters of sound absorption block (4).
6, external labeling type broadband transducers according to claim 1, it is characterized in that shielding case (10) and pedestal (15) form columniform screening can, its overall height is 1/2～1/3 of a diameter, and accessory power outlet (9) is arranged on the side of shielding case (10).
7, external labeling type broadband transducers according to claim 1 is characterized in that being made up of a plurality of at the disk (5) of pedestal (15) bottom, is uniformly distributed on the same circumference, and two magnetic poles of its disk (5) are adjacent oppositely setting each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031126448A CN1186628C (en) | 2003-01-10 | 2003-01-10 | External adhesive composite wide band transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031126448A CN1186628C (en) | 2003-01-10 | 2003-01-10 | External adhesive composite wide band transducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1425916A CN1425916A (en) | 2003-06-25 |
| CN1186628C true CN1186628C (en) | 2005-01-26 |
Family
ID=4790226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031126448A Expired - Fee Related CN1186628C (en) | 2003-01-10 | 2003-01-10 | External adhesive composite wide band transducer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1186628C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10161919B2 (en) * | 2016-10-25 | 2018-12-25 | Fisher Controls International Llc | Acoustic emission sensors with integral acoustic generators |
| JP6939429B2 (en) | 2017-11-02 | 2021-09-22 | 株式会社デンソー | Ultrasonic sensor |
| CN112285202A (en) * | 2020-10-20 | 2021-01-29 | 天津大学 | Variable-curvature PBX surface crack oriented nondestructive testing method and sensor |
-
2003
- 2003-01-10 CN CNB031126448A patent/CN1186628C/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| CN1425916A (en) | 2003-06-25 |
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