Acoustic Emission Sensors
Acoustic Emission Sensors
Specification
Released 12-2015
Contact Address
Vallen Systeme GmbH
Schaeftlarner Weg 26a
D-82057 Icking
Germany
email: info@vallen.de
http://www.vallen.de
Tel:
Fax:
+49 8178 9674-400
+49 8178 9674-444
Specifications are subject to change as product developments are made.
Comments and recommendations are appreciated and may be mailed to: sales@Vallen.de
Copyright © 2016, Vallen Systeme GmbH
All rights reserved.
Electronic versions of this document may be read online, downloaded for personal use, or
referenced in another document as a URL to a Vallen website. No part of this specification may
be published commercially in print or electronic form, edited, translated, or otherwise altered
without the permission of Vallen.
Trademarks and Licenses
The hardware and/or software described herein are furnished under a license and may be used
or copied only in accordance with the terms of such license.
AMSY-5, AMSY-6, ASIP-2, VisualAE, VisualClass and VisualTR are trademarks of Vallen
Systeme GmbH
Disclaimer
The material contained in this document is provided “as is” and is subject to being changed,
without notice, in future editions. Further, to the maximum extent permitted by applicable law,
we, Vallen Systeme GmbH, disclaim all warranties, either expressed or implied with regard to
this specification and any information contained herein, including but not limited to the implied
warranties of merchantability and fitness for a particular purpose. We, Vallen Systeme GmbH,
shall not be liable for errors or for incidental or consequential damages in connection with the
furnishing, use, or performance of this document or any information contained herein.
We shall not be liable for any direct, indirect, consequential or incidental damage arising out of
the use or inability to use of the equipment delivered. We reserve the right to charge for any
efforts taken to remedy any problems for which we are not responsible.
Revision Record
Changes
Date
12-2015
12-2015
Codes for sensor cables renamed.
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Purpose of this Document
This document:
• Gives hints on how to select an appropriate AE-sensor for a specific application and AEsensor handling
• Describes physical dimensions, frequency range and environmental conditions of Vallen AEsensors
• Provides reference frequency response diagrams for certain AE-sensor types.
Contents
1
Introduction ....................................................................................................................... 5
2
Guide for Acoustic Emission Sensor Selection ............................................................ 5
2.1
Environmental conditions ................................................................................................ 5
2.2
Frequency range ............................................................................................................. 6
2.2.1
Overview of frequency regimes and applications .................................................. 7
2.2.2
Determining the correct frequency range of AE-sensors for an integrity testing
application .............................................................................................................. 7
2.3
AE-sensor size and frequency response ........................................................................ 8
2.4
Integrated preamplifier vs. external preamplifier ............................................................ 8
2.5
Sensor coupling verification pulse .................................................................................. 8
3
AE-sensor nomenclature ................................................................................................. 9
4
Overview of AE sensors ................................................................................................. 10
4.1
Standard environment models ...................................................................................... 10
4.2
Watertight AE-sensors .................................................................................................. 12
4.3
High temperature AE-sensor ........................................................................................ 13
4.4
AE-sensors for hazardous areas .................................................................................. 13
4.5
Third party AE-sensors with longer delivery time .........................................................13
5
AE-Sensor Data Sheets .................................................................................................. 15
5.1
Standard environment AE-sensors ............................................................................... 15
5.1.1
VS30-V ................................................................................................................. 15
5.1.2
VS30-SIC-46dB.................................................................................................... 16
5.1.3
VS45-H ................................................................................................................. 17
5.1.4
VS75-V ................................................................................................................. 18
5.1.5
VS75-SIC-34dB.................................................................................................... 19
5.1.6
VS75-SIC-40dB.................................................................................................... 20
5.1.7
VS75-SI-40dB ...................................................................................................... 21
5.1.8
VS150-M .............................................................................................................. 22
5.1.9
VS150-MS ............................................................................................................ 23
5.1.10 VS150-L ............................................................................................................... 24
5.1.11 VS150-R ............................................................................................................... 25
5.1.12 VS150-K ............................................................................................................... 26
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5.1.13 VS150-RIC ........................................................................................................... 27
5.1.14 VS370-A1 ............................................................................................................. 28
5.1.15 VS370-A2 ............................................................................................................. 29
5.1.16 VS375-M .............................................................................................................. 30
5.1.17 VS375-RIC ........................................................................................................... 31
5.1.18 VS600-A1 ............................................................................................................. 32
5.1.19 VS600-A2 ............................................................................................................. 33
5.1.20 VS600-Z1 ............................................................................................................. 34
5.1.21 VS600-Z2 ............................................................................................................. 35
5.1.22 VS700-D ............................................................................................................... 36
5.1.23 VS900-M .............................................................................................................. 37
5.1.24 VS900-RIC ........................................................................................................... 38
5.2
5.3
Watertight AE-sensors .................................................................................................. 39
5.2.1
VS150-K2 ............................................................................................................. 39
5.2.2
VS150-WIC-V01................................................................................................... 40
5.2.3
VS375-WIC-V01................................................................................................... 41
5.2.4
VS900-WIC-V01................................................................................................... 42
High temperature AE-sensor ........................................................................................ 43
5.3.1
5.4
AE-sensors for hazardous areas .................................................................................. 44
5.5
Third party AE-sensors with longer delivery time .........................................................44
5.5.1
AE1045S .............................................................................................................. 44
5.5.2
AE2045S .............................................................................................................. 44
5.5.3
AE104A ................................................................................................................ 45
5.5.4
AE105A ................................................................................................................ 45
5.5.5
AE144A ................................................................................................................ 45
5.5.6
AE204A ................................................................................................................ 46
5.5.7
M31 ...................................................................................................................... 46
5.5.8
M58 ...................................................................................................................... 46
6
Warranty .......................................................................................................................... 47
7
Appendix .......................................................................................................................... 48
7.1
7.2
12-2015
VS160-NS ............................................................................................................ 43
AE-sensor handling ...................................................................................................... 48
Mounting of AE-sensors ............................................................................................... 48
7.2.1
Compression mount ............................................................................................. 48
7.2.2
Adhesive mount (bonding) ................................................................................... 48
7.3
Usage of couplant ......................................................................................................... 49
7.4
AE-Sensor verification .................................................................................................. 49
7.4.1
Frequency Response Measurement .................................................................... 50
7.4.2
Pressure Excitation .............................................................................................. 50
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1
Introduction
The sensor constitutes the first part in an AE measurement chain and as of this is of particular
importance. A subsequent measurement system can only process signals which the AE-sensor
picked up. Anything an AE-sensor does not pick up is lost for analysis.
An AE-sensor converts the surface movement caused by an elastic wave into an electrical
signal which can be processed by the measurement equipment. The piezoelectric element of
the AE-sensor should pick up faintest surface movements (i.e. have high sensitivity) and convert
this movement most efficiently to an electrical voltage.
AE-sensors can be designed highly sensitive at a certain frequency (also termed resonant) or
with a broad frequency response (broad band). Special AE-sensor models for high
temperatures are also available as well as ATEX certified sensors for installation in hazardous
area. Our ATEX certified sensors are not part of this specification but described in an own
specification (see Note below).
The following sections of this document give an overview about the right AE-sensor selection for
an application and detailed specifications of the Vallen Systeme sensor product range.
2
Guide for Acoustic Emission Sensor Selection
Vallen Systeme GmbH provides various sensors for all kinds of AE-applications. Selecting an
appropriate sensor for a specific AE-application is crucial for the success of the measurement.
In most cases the main criterion for the AE-sensor selection should be the frequency response
which must suit the application. In some special applications environmental and legal
requirements (e.g. high temperature, water/oil tightness, hazardous area installation) may pose
more severe restrictions on AE-sensor selection than the frequency response. This chapter
gives useful hints on how to select a suitable AE-sensor for every application. For more
information about our AE-sensors, AE-sensor selection or specific applications please contact
us directly at info@vallen.de.
2.1
Environmental conditions
The majority of AE-sensors are specified for normal environmental conditions as one would face
during field testing or in the lab. However some applications on hot machinery surfaces require
special AE-sensors. Using the AE-sensors outside of the specified temperature range could
cause permanent damage to the sensor or corrupt the sensor signal. For high temperature
environments only a few AE-sensors may be suitable and the temperature range should be the
first criterion to constrict the AE-sensor variety.
Some applications have a demand for AE-sensors suitable for installation in hazardous areas or
for water-/oil resistant AE-sensors. Special solutions are available for this demand and need to
be first priority for the AE-sensor selection.
Note: AE-sensors for hazardous areas
Vallen Systeme offers an intrinsically safe product family (ISAFE3). This product family is ATEX
certified and consists not only of a family of AE-sensors but also of special signal isolator to fulfil
all safety requirements for hazardous areas of zone 0, zone 1 or zone 2. For more details
please see the ‘Vallen ISAFE3 Operation Manual’ or contact us at info@vallen.de.
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2.2
Frequency range
Vallen Systeme follows a coarse and arbitrary classification into 3 frequency regimes, which is
justified by the fact that most applications can be classified into one of these frequency regimes:
low (20 kHz - 100 kHz), standard (100 kHz - 400 kHz) and high (>400 kHz). Attenuation per unit
distance increases with frequency. For most applications, frequencies above 400 kHz are
meaningless and are cut-off in order to minimize electronic noise. Some standard preamplifiers
and signal processors are able to process frequencies up to 2.2 MHz (e.g. AMSY-6). The
classification in low-, standard- and high frequency regime is arbitrary and there are applications
which use different frequency classes dependent on the presence of background noise (move
to higher frequencies) or wide sensor spacing (move to lower frequencies). However, for the
majority of applications this classification is useful for getting a fast overview.
AE-sensors that respond uniformly to a very broad band of exciting frequencies are referred to
as broadband or wideband sensors. Wideband AE-sensors with a flat response curve are
usually desired if the frequency of interest is still unknown (e.g. research or feasibility study) or if
different frequencies in one signal should be analyzed (e.g. modal analysis).
Most AE-sensors are of resonant type which means they are most sensitive at their resonance
frequency. These AE-sensors may have other frequency bands where their sensitivity is low.
The resonance frequency is the decisive factor for which application these AE-sensors can be
used.
Resonant AE-sensors are usually used if the frequency content itself is not of interest but only
AE features such as amplitude, arrival time or energy. To clarify: These features are - to some
extend - affected by the peak frequency and frequency range of the AE-sensor. Therefore AEfeatures can only be compared if recorded with the same AE-sensor type.
Finding the right frequency range for a specific application has to consider factors such as
material, specimen size and background noise. Attenuation is frequency dependent: the higher
the frequency, the higher is the attenuation per unit distance. Usually the AE-sensor spacing
can be extended when moving to lower frequencies. On the other hand background noise, such
as from production machinery, is usually more prominent in lower frequency range (<100 kHz).
Therefore false triggering can be avoided when moving to higher frequencies.
Note:
Most EN- or ASTM standards recommend a frequency range for an application and an operator
or inspector should stick to this recommendation.
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2.2.1
Overview of frequency regimes and applications
Certain frequency ranges have been proven to be best suitable for specific applications.
Application
20-100 kHz
Corrosion screening of flat bottom storage
tanks
x
Leakage detection in water/oil pipelines
x
100-400 kHz
Hot reheat pipe crack detection
x
Integrity testing of pressure vessels
x
Partial discharge detection
x (when noise
>400 kHz
x
is low)
Integrity testing of metallic structures
x
Integrity testing of composite materials
x
Integrity testing of concrete structures
x
Drying process monitoring of plants/wood
x
AE-testing of small specimen
2.2.2
x
Determining the correct frequency range of AE-sensors for an integrity
testing application
The elastic wave is usually heavily affected by the propagation mechanisms before it reaches
the AE-sensor. The frequency content of the wave is particularly affected by the source
mechanism as well as the material through which the wave propagates.
The material in which an elastic wave propagates has a very inhomogeneous effect on the
frequency distribution; attenuating certain frequencies stronger than others. Also wave
propagation could be affected by macroscopic features of the test object, e.g. dispersion
(different wave velocities at different frequencies) in plate like structures.
The correct frequency range for a certain application can be determined experimentally where
possible. A very flat-response broadband AE-sensor and AE-measurement equipment is
needed. The broadband AE-sensor shall be mounted to the object. Pencil lead breaks (HsuNielsen source) are used to excite elastic waves which the AE-sensor picks up. The waveforms
of the measured signals can be characterized for their primary frequency content by performing
Fast Fourier Transforms (FFT) on the signals. The FFTs should be done on the time periods of
the signal that have the highest amplitudes. AE-sensor selection is guided by the primary
frequency content identified by the FFTs. An AE-sensor (wideband or resonant) should have
significant response over the range of frequencies excited with the highest amplitudes.
Note for AE-source mechanisms not related to crack initiation or - propagation:
The above mentioned method is applicable in cases were a pencil lead break is a good
equivalent for an AE-source. This may not be the case for all AE source mechanisms (e.g.
leakage). A similar approach would be possible if a different artificial AE-source is applied which
is similar to the expected source.
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Note for plate like structures:
If the object under test is a plate like structure, pencil lead breaks should be performed in a
sufficient distance from the AE-sensor in order that only plate waves excite the AE-sensor.
Usually distances larger than 20x plate thickness are sufficient. Additionally pencil lead breaks
should be made on the top (or bottom side) of the plate, to generate asymmetric wave modes,
and, if possible, at the center of the plate’s edge to generate symmetrical wave modes.
2.3
AE-sensor size and frequency response
The size of the piezoelectric element affects the resonance frequency of the AE-sensor. In
general the resonance frequency is higher for smaller piezo-elements. Therefore the desired
resonance frequency has a major influence on the sensor size; i.e. the lower the frequency
range of an AE-sensor the larger its size.
2.4
Integrated preamplifier vs. external preamplifier
Vallen Systeme GmbH provides AE-sensors with and without integrated preamplifier. AEsensors with integrated preamplifier are referred to as active sensors, whereas those without
integrated preamplifiers are referred to as passive sensors. In general AE-sensors with
integrated preamplifier are larger and heavier than similar AE-sensors without integrated
preamplifier. However, AE-sensors with integrated preamplifier are better suited for usage in the
field, because measurement setup can be realized faster and the number of connectors which
can be mixed-up is reduced. Especially thin cables such as the sensor-to-preamplifier cable
may be troublesome in the field since they must be handled with extra care.
Passive AE-sensors require an external preamplifier. The cable length between AE-sensor and
external preamplifier is usually 1.2 meters and should not be further extended unless the setup
cannot be realized with this cable length. The shorter the cable from sensor to preamplifier, the
higher is the sensitivity of the sensor. The lower the AE-sensor's capacity, the worse the
influence of cable length on the sensitivity. The cable transmitting the signal from the
preamplifier to the measuring system can be several hundred meters long.
In general AE-sensors with integrated preamplifier are more cost effective than a similar passive
AE-sensor together with an external preamplifier. The additional costs of the second solution
can be justified by a more flexible setup when for instance the gain of the external preamplifier
or the frequency response of AE-sensor needs to be adapted for different applications.
2.5
Sensor coupling verification pulse
The piezoelectric element of an AE-sensor transforms mechanical vibrations into an electrical
signal. In turn, an electrical pulse applied to the piezoelectric element results in a mechanical
excitation which could be used to emit a mechanical wave into the test object. This wave can be
used for instance to verify the sensor coupling quality.
A voltage pulse is transmitted from the AE system (i.e. AMSY series) through the preamplifier to
the AE-sensor and generates a wave in the structure under test. The wave from the pulsing AEsensor propagates through or along the test object and can be picked up by neighboring AEsensors. The amplitude of the received AE-signal gives an indication whether an AE-sensor is
coupled appropriately to the structure.
The preamplifier must support the so-called "pulse through” functionality. That means, the
preamplifier, when not supplied by 28 VDC, internally disconnects the preamplifier output from
the cable that delivers the high voltage pulse, in order to prevent damage from the preamplifier,
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and connects the high voltage pulse to the piezo electric sensor element. Preamplifiers that do
not support the pulse through functionality must not be used for pulsing, because they might get
damaged permanently. The user of an AMSY-6 (or its predecessors) can define in a software
menu which kind of preamplifier is connected to a signal processor. All Vallen Systeme external
preamplifiers (i.e. AEP series, see “Acoustic Emission Preamplifier” document) support the
pulse through capability. Most Vallen Systeme AE-sensors with integrated preamplifiers also
support the pulse through functionality. This is indicated by a “C” (calibration bypass) at the end
of the AE-sensor name, e.g. VS150-RIC (see Chapter 3 AE-sensor nomenclature). All passive
AE-sensors (without integrated preamplifier) can be used for pulsing anyway.
Vallen Systeme supports another pulsing mode for its intrinsically safe AE-sensors. Hereby only
a low energy control signal is transmitted from the signal processor to the sensor and sensorinternal electronics is used to supply a high energetic pulse to the piezoelectric element,
because high energetic pulses are prohibited on intrinsically safe circuit cables.
By investigating the post-pulse oscillation of the piezoelectric element, which is influenced by
coupling, the coupling quality of the pulsing AE-sensor can be verified. This coupling verification
method is referred to as ‘auto sensor test - self test mode' in ASTM E2374-04.
Investigating the pulse received by neighboring sensors is called 'auto sensor test - near
neighbor mode’.
3
AE-sensor nomenclature
Most Vallen Sensors are named systematically by its peak frequency and information about the
case type and preamplifier information:
Third party sensors are labeled differently, these sensors are AExxxx, M31 and M58.
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4
Overview of AE sensors
The following tables give a short overview of the main parameters of sensors. The column “Details on page” refers to the page where you find a more detailed
description and the frequency response curve of the respective sensor.
For specification of sensor cables and magnetic holders please see our specification of “Accessories for Acoustic Emission Systems”. For information about
preamplifiers (external preamplifiers as well as preamplifiers integrated in sensor) please see our specification of “Acoustic Emission Preamplifiers”.
4.1
Standard environment models
AE-sensor
Model
Freq.
Range
[kHz]
fPeak Details
on
[kHz] page
Size DxH
Weight
[mm]
[g]
Case
Material
Wear
Plate
Temp.
Range
[°C]
Connector Capacity
[pF]
Comment
VS30-V
25-80
15
20.3 x 37
69
Stainless
steel
Ceramics
-5 to +85
Microdot
VS30-SIC-46dB
25-80
16
28.6 x 51.8
170
Stainless
steel
Ceramics
-5 to +85
BNC
VS45-H
20-450
280
17
20.3 x 22
36
Aluminum
Ceramics
-20 to +100
Microdot
270
MAG4H
VS75-V
30-120
75
18
20.3 x 37
63
Stainless
steel
Ceramics
-5 to +85
Microdot
140
MAG4V
VS75-SIC-34dB
30-120
75
19
20
28.6 x 51.8
162
Stainless
steel
Ceramics
-5 to +85
BNC
VS75-SIC-40dB
140
Magnetic
holder
MAG4V
Integrated preamplifier:
46dB gain
Integrated preamp.: 34dB gain
MAG4SI
MAG4SI
Integrated preamp.: 40dB gain
VS75-SI-40dB
30-120
75
21
28.6 x 51.8
161
Stainless
steel
Ceramics
-5 to +85
BNC
VS150-M
100-450
150
22
20.3 x 14.3
24
Stainless
steel
Ceramics
-50 to +100
Microdot
350
MAG4M
VS150-MS
100-450
150
23
20.3 x 14.3
24
Stainless
steel
Ceramics
-50 to +100
SMC
350
MAG4M
VS150-L
100-450
150
24
20.3 x 14.3
26
Stainless
steel
Stainless
steel
-50 to +100
SMC
350
MAG4M
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Integrated preamp.: 40dB gain
No pulse through
MAG4SI
Page 10 of 50
AE-sensor
Model
Freq.
Range
[kHz]
fPeak Details
on
[kHz] page
Size DxH
Weight
[mm]
[g]
Case
Material
Wear
Plate
Temp.
Range
[°C]
Connector Capacity
[pF]
VS150-R
100-450
150
25
28.6 x 31.5
81
Stainless
steel
Ceramics
-40 to +85
BNC
350
VS150-K
100-450
150
26
20.3 x 22
45
Stainless
steel
Stainless
steel
-50 to +100
SMC
350
VS150-RI
100-450
150
none
28.6 x 31.5
81
Stainless
steel
Ceramics
-40 to +85
VS150-RIC
100-450
150
27
28.6 x 31.5
81
Stainless
steel
Ceramics
VS370-A1
170-590
370
28
M7x0.75 x
13.5
3
Stainless
steel
VS370-A2
170-590
370
29
8.5 x 13
3.5
M7x0.75 x
8.5
MAG4R
MAG4H
BNC
Integrated preamp.: 40dB gain
No pulse through
MAG4R
-40 to +85
BNC
Integrated preamp.: 34dB gain
MAG4R
Stainless
steel
-40 to 125
SMC (top)
47
Stainless
steel
Stainless
steel
-40 to 125
SMC (top)
47
390
250-700
375
30
20.3 x 14.3
21
Stainless
steel
Ceramics
-50 to +100
Microdot
VS375-RIC
250-700
375
31
28.6 x 31.5
80
Stainless
steel
Ceramics
-40 to +85
BNC
VS600-A1
390-850
600
32
M7x0.75 x
13.5
2.5
Stainless
steel
Stainless
steel
-40 to 125
SMC (top)
109
VS600-A2
390-850
600
33
8.5 x 13
3
Stainless
steel
Stainless
steel
-40 to 125
SMC (top)
109
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Magnetic
holder
Enhanced ingress protection
rating IP54 with connected
cable.
VS375-M
M7x0.75 x
8.5
Comment
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Acoustic Emission Sensors - Specification
MAG4A1
optimized for magnetic holder
MAG4A1
MAG4A1
MAG4M
Integrated preamp.: 34dB gain
MAG4R
MAG4A1
optimized for magnetic holder
MAG4A1
MAG4A1
Page 11 of 50
AE-sensor
Model
VS600-Z1
Freq.
Range
[kHz]
550-730
fPeak Details
on
[kHz] page
600
34
Size DxH
Weight
[mm]
[g]
4.75 x 5.8
0.8
20
VS600-Z2
400-800
600
35
4.75 x 5.3
VS700-D
150-800
600 800
36
6.3 x 10
2
0.8
20
1
2
1.5
20
1
1
2
Case
Material
Wear
Plate
Temp.
Range
[°C]
Connector Capacity
[pF]
Stainless
steel
Ceramics
-10 to +110
SMA/BNC
Stainless
steel
Stainless
steel
-40 to +110
SMA/BNC
E-copper,
tinned
Neodyne
-20 to +70
200
4
100 cm integral cable
-
3
200
4
100 cm integral cable
-
SMA/BNC
3
163
4
35 cm integral cable
Integral
540
100-900
350
37
20.3 x 14.3
22
Stainless
steel
Ceramics
-50 to +100
Microdot
VS900-RIC
100-900
350
38
28.6 x 31.5
80
Stainless
steel
Ceramics
-40 to +85
BNC
Weight
Case
Material
Wear
Plate
Temp.
Range
[°C]
Stainless
steel
Stainless
steel
MAG4M
Integrated preamp.: 34 dB gain
MAG4R
Comment
Magnetic
holder
Watertight AE-sensors
AE-sensor
Model
VS150-K2
Magnetic
holder
3
VS900-M
4.2
Comment
Freq.
Range
[kHz]
100-450
fPeak Details Size DxH
on
[kHz] page
[mm]
150
39
20.3 x 22
[g]
56
Connector Capacity
[pF]
-40 to +100 SMC on 1 m
integrated
cable
350
IP code IP68
MAG4H
1
Weight without integral cable
Weight with integral cable
3
SMA to BNC adapter included
4
Capacity with integral cable
2
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AE-sensor
Model
Freq.
Range
[kHz]
fPeak Details Size DxH
on
[kHz] page
[mm]
Weight
Case
Material
Wear
Plate
Temp.
Range
[°C]
[g]
Connector Capacity
[pF]
Comment
Magnetic
holder
VS150-WICV01
100-450
150
40
32.0 x 48.0
184
Stainless
steel
Ceramics
-40 to +85
LEMO
Integrated preamp.: 34dB gain
IP code IP68 with con. cable
MAG4W
-V1
VS375-WICV01
250-700
375
41
32.0 x 48.0
181
Stainless
steel
Ceramics
-40 to +85
LEMO
Integrated preamp.: 34dB gain
IP code IP68 with con. cable
MAG4W
-V1
VS900-WICV01
100-900
350
42
32.0 x 48.0
184
Stainless
steel
Ceramics
-40 to +85
LEMO
Integrated preamp.: 34dB gain
IP code IP68 with con. cable
MAG4W
-V1
Weight
Case
Material
Wear
Plate
Temp.
Range
[°C]
Comment
Magnetic
holder
Stainless
steel
Ceramics
-50 to +180
4.3
High temperature AE-sensor
AE-sensor
Model
VS160-NS
4.4
Freq.
Range
[kHz]
100-450
fPeak Details Size DxH
on
[kHz] page
[mm]
150
43
20.3 x 14.3
[g]
22
Connector Capacity
[pF]
SMC
350
MAG4NS
AE-sensors for hazardous areas
Vallen Systeme offers an intrinsically safe product family (ISAFE3). This product family is ATEX certified and consists not only of a family of AE-sensors but also of
special signal isolator to fulfil all safety requirements for hazardous areas of zone 0, zone 1 or zone 2. For more details please see the ‘Vallen ISAFE3 Operation
Manual’ or contact us at info@vallen.de.
4.5
Third party AE-sensors with longer delivery time
AE-sensor
Model
AE1045S
12-2015
Freq.
Range
[kHz]
100-1500
fPeak Details
on
[kHz] page
Flat
44
Size DxH
Weight
[mm]
[g]
20 x 20
31
Case
Material
Wear
Plate
Temp.
Range
[°C]
Stainless
steel
Ceramics
-20 to +80
file: sov1512.docm
Acoustic Emission Sensors - Specification
Connector Capacity
[pF]
Microdot
89
Comment
Magnetic
holder
MAG4S
Page 13 of 50
Freq.
Range
[kHz]
AE-sensor
Model
fPeak Details
on
[kHz] page
Size DxH
Weight
[mm]
[g]
Case
Material
Wear
Plate
Temp.
Range
[°C]
Connector Capacity
[pF]
Comment
Magnetic
holder
AE2045S
200-2500
Flat
44
20 x 20
31
Stainless
steel
Ceramics
-20 to +80
Microdot
140
MAG4S
AE104A
100-400
Flat
45
8 x 18
5
Stainless
steel
Ceramics
-20 to +80
Microdot
40
MAG4A
AE105A
450-1150
800
45
8 x 18
5
Stainless
steel
Ceramics
-20 to +80
Microdot
60
MAG4A
AE144A
100-500
200
45
8 x 18
5
Stainless
steel
Ceramics
-20 to +80
Microdot
30
MAG4A
AE204A
180-700
375
46
8 x 18
5
Stainless
steel
Ceramics
-20 to +80
Microdot
46
MAG4A
M31
300-800
750
46
3x3
0.2
5
Stainless
steel
Ceramics
-20 to +80
Microdot /
6
BNC
89
7
M58
700-900
750
and
800
46
5x3
0.4
5
Stainless
steel
Ceramics
-20 to +80
Microdot /
6
BNC
260
7
50 cm integral cable
-
100 cm integral cable
-
Note:
The lower the AE-sensor's capacity the worse the influence of cable length
5
Weight without integral cable
Microdot to BNC adapter included
7
Capacity with integral cable
6
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
Page 14 of 50
5
AE-Sensor Data Sheets
For specification of sensor cables and magnetic mounting holders please see our specification of
“Accessories for Acoustic Emission Systems”. For information about preamplifiers (external preamplifiers as
well as preamplifiers integrated in sensor) please see our specification of “Acoustic Emission Preamplifiers”.
5.1
Standard environment AE-sensors
5.1.1
VS30-V
VS30-V
The VS30-V is a passive piezoelectric AE-sensor. The low frequency response makes it especially suited
for monitoring large objects or objects made of highly attenuating material. The VS30-V can be used for
tank floor corrosion and leak detection, leak detection in pipelines, partial discharge detection and integrity
testing of concrete structures.
Remark to frequency response curve below: cable used: RG 178/ 0.3m. VS30-V has 6 dB less sensitivity if
used with 1.2 m long cable.
-60
dB re
1V/µbar
-70
-80
-90
20
40
60
80
100
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
25 to 80
Size (D x H) [mm]
20.3 x 37.0
Capacity [pF]
140
Weight [g]
69
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-5 to +85
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
Microdot
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N, AEP4H-ISTB
Sensor Cable
CBL-1-1M2-V5
Mounting Holder
MAG4V, AEP4H-ISTB
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
15 of 50
5.1.2
VS30-SIC-46dB
VS30-SIC-46dB
The VS30-SIC-46dB is a piezoelectric AE-sensor with integrated preamplifier. The low frequency response
makes it especially suited for monitoring large objects or objects made of highly attenuating material. The
VS30-SIC-46dB can be used for tank floor corrosion and leak detection, leak detection in pipelines, partial
discharge detection and integrity testing of concrete structures.
The integrated preamplifier has 46 dB gain and supports pulse through for automatic sensor testing.
-10
-20
dB re
1V/µbar -30
-40
-50
-60
20
40
60
80
100
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
25 to 80
Size (D x H) [mm]
28.6 x 51.8
Power Supply [vDC]
28 ± 2
Weight [g]
170
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
46
Connector
BNC
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-5 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
18.5 @ 25 - 45 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
2.6 @ 25 - 45 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4SI
file: sov1512.docm
Acoustic Emission Sensors - Specification
16 of 50
5.1.3
VS45-H
VS45-H
The VS45-H is a passive piezoelectric AE-sensor with a wide frequency response. Its frequency response
is characterized by a peak at 280 kHz and can be used in the frequency range from 40 kHz to 450 kHz. It is
a broad band response AE-sensor covering the low frequency and standard frequency range.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
20 to 450 (280)
Size (D x H) [mm]
20.3 x 22.0
Capacity [pF]
270
Weight [g]
36
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-20 to +100
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
Microdot
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V5
Mounting Holder
MAG4H
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
17 of 50
5.1.4
VS75-V
VS75-V
The VS75-V is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at 75
kHz where it exhibits a resonance. The low frequency response makes it suited for monitoring large objects
or objects made of highly attenuating material. The VS75-V can be used for integrity testing of bitumen
coated pressure vessels and for detecting partial discharge.
Remark to frequency response curve below: cable used: RG 178/ 0.3m. VS75-V has 6 dB less sensitivity if
used with 1.2 m long cable.
-60
dB re
1V/µbar
-70
-80
20
40
60
80
100
120
140
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
30 to 120 (75)
Size (D x H) [mm]
20.3 x 37.0
Capacity [pF]
140
Weight [g]
63
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-5 to +85
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
Microdot
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V5
Mounting Holder
MAG4V
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
18 of 50
5.1.5
VS75-SIC-34dB
VS75-SIC-34dB
The VS75-SIC-34dB is an AE-sensor with integrated preamplifier. Its frequency response is characterized
by a peak at 75 kHz where it exhibits a resonance. The low frequency response makes it suited for
monitoring large objects or objects made of highly attenuating material. The VS75-SIC-34dB can be used
for integrity testing of bitumen coated pressure vessels and for detecting partial discharge.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re
-30
1V/µbar
-40
-50
20
40
60
80
100
120
140
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
30 to 120 (75)
Size (D x H) [mm]
28.6 x 51.8
Power Supply [vDC]
28 ± 2
Weight [g]
162
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
BNC
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-5 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
29.2 @ 25 - 300 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
6.8 @ 25 - 300 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4SI
file: sov1512.docm
Acoustic Emission Sensors - Specification
19 of 50
5.1.6
VS75-SIC-40dB
VS75-SIC-40dB
The VS75-SIC-40dB is a piezoelectric AE-sensor with integrated preamplifier. Its frequency response is
characterized by a peak at 75 kHz where it exhibits a resonance. The low frequency response makes it
suited for monitoring large objects or objects made of highly attenuating material. The VS75-SIC-40dB can
be used for integrity testing of bitumen coated pressure vessels and for detecting partial discharge.
The integrated preamplifier has 40 dB gain and supports pulse through for automatic sensor testing.
-15
dB re
-25
1V/µbar
-35
-45
20
40
60
80
100
120
140
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
30 to 120 (75)
Size (D x H) [mm]
28.6 x 51.8
Power Supply [vDC]
28 ± 2
Weight [g]
162
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
40
Connector
BNC
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-5 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
29.5 @ 25 - 300 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
7.3 @ 25 - 300 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4SI
file: sov1512.docm
Acoustic Emission Sensors - Specification
20 of 50
5.1.7
VS75-SI-40dB
VS75-SI-40dB
The VS75-SIC-40dB is a piezoelectric AE-sensor with integrated preamplifier. Its frequency response is
characterized by a peak at 75 kHz where it exhibits a resonance. The low frequency response makes it
suited for monitoring large objects or objects made of highly attenuating material. The VS75-SIC-40dB can
be used for integrity testing of bitumen coated pressure vessels and for detecting partial discharge.
The integrated preamplifier has 40 dB gain.
-20
dB re
1V/µbar
-30
-40
20
40
60
80
100
120
140
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
30 to 120 (75)
Size (D x H) [mm]
28.6 x 51.8
Power Supply [vDC]
28 ± 2
Weight [g]
161
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
40
Connector
BNC
Pulse Through
No
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-5 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
29.5 @ 25 - 300 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50Hz, 20 g
Typ. Noise [µVRMS]
7.3 @ 25 - 300 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4SI
file: sov1512.docm
Acoustic Emission Sensors - Specification
21 of 50
5.1.8
VS150-M
VS150-M
The VS150-M is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at
150 kHz where it exhibits a resonance. It is suitable for almost all AE application and especially suited for
integrity inspection of metallic pressure vessels.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
20.3 x 14.3
Capacity [pF]
350
Weight [g]
24
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +100
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
Microdot
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V5
Mounting Holder
MAG4M
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
22 of 50
5.1.9
VS150-MS
VS150-MS
The VS150-MS is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at
150 kHz where it exhibits a resonance. It is suitable for almost all AE application and especially suited for
integrity inspection of metallic pressure vessels.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
20.3 x 14.3
Capacity [pF]
350
Weight [g]
24
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +100
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4M
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
23 of 50
5.1.10
VS150-L
VS150-L
The VS150-L is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at
150 kHz where it exhibits a resonance. It is suitable for almost all AE application. The VS150-L has a full
metal housing that makes it especially suited for adhesively mounting it to a test object. In this respect it is
suited for inspecting objects that have no ferro-magnetic surface such as composites and Al alloys.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
20.3 x 14.3
Capacity [pF]
350
Weight [g]
26
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +100
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4M
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
24 of 50
5.1.11
VS150-R
VS150-R
The VS150-R is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at
150 kHz where it exhibits a resonance. It is suitable for almost all AE application and especially suited for
integrity inspection of metallic pressure vessels.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
28.6 x 31.5
Capacity [pF]
350
Weight [g]
81
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +85
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
BNC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-xM-V1
Mounting Holder
MAG4R
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
25 of 50
5.1.12
VS150-K
VS150-K
The VS150-K is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at
150 kHz where it exhibits a resonance. It is suitable for almost all AE application. The VS150-K has a full
metal housing and a watertight cap and it is rated IP54. The mechanical design makes it especially suited
for adhesively mounting it to a test object.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
20.3 x 22
Capacity [pF]
350
Weight [g]
45
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +100
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC
Ingress Protection Rating
IP54 (with connected cable)
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4H
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
26 of 50
5.1.13
VS150-RIC
VS150-RIC
The VS150-RIC is a piezoelectric AE-sensor with integrated preamplifier. Its frequency response is
characterized by a peak at 150 kHz where it exhibits a resonance. It is suitable for almost all AE application
and especially suited for integrity inspection of metallic pressure vessels.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re -30
1V/µbar
-40
-50
-60
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
28.6 x 31.5
Power Supply [vDC]
28 ± 2
Weight [g]
81
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
BNC
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-40 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
25.2 @ 95 - 300 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
5.0 @ 95 - 300 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4R
file: sov1512.docm
Acoustic Emission Sensors - Specification
27 of 50
5.1.14
VS370-A1
VS370-A1
The VS370-A1 or -A2 is a passive piezoelectric AE-sensor. Its frequency response is characterized by a
peak at 370 kHz where it exhibits a resonance. It is a small foot-print AE-sensor with a threaded housing
and a top connector. The VS370-A* is intended for screwing it into a holding mechanism.
-70
dB re
-80
1V/µbar
-90
-100
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
170 to 590 (370)
Size (D x H) [mm]
7.0 x 13.5 (M7 x 0.75)
Capacity [pF]
47
Weight [g]
3
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +125
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC (top)
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4A1
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
28 of 50
5.1.15
VS370-A2
VS370-A2
The VS370-A1 or -A2 is a passive piezoelectric AE-sensor. Its frequency response is characterized by a
peak at 370 kHz where it exhibits a resonance. It is a small foot-print AE-sensor with a threaded housing
and a top connector. The VS370-A* is intended for screwing it into a holding mechanism.
-70
dB re
-80
1V/µbar
-90
-100
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
170 to 590 (370)
Size (D x H) [mm]
8.5 x 13.0 (M7 x 0.75 x 8.5)
Capacity [pF]
47
Weight [g]
3.5
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +125
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC (top)
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4A1
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
29 of 50
5.1.16
VS375-M
VS375-M
The VS375-M is a passive piezoelectric AE-sensor. Its frequency response is characterized by a peak at
375 kHz where it exhibits a resonance. Its frequency response bridges the gap between standard
frequency range and high frequency range. It is especially suited for integrity inspection of high energy
piping in conjunction with using a waveguide.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
250 to 700 (375)
Size (D x H) [mm]
20.3 x 14.3
Capacity [pF]
390
Weight [g]
21
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +100
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
Microdot
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V5
Mounting Holder
MAG4M
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
30 of 50
5.1.17
VS375-RIC
VS375-RIC
The VS375-RIC is a piezoelectric AE-sensor with integrated preamplifier. Its frequency response is
characterized by a peak at 375 kHz where it exhibits a resonance. Its frequency response bridges the gap
between standard frequency range and high frequency range.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re -30
1V/µbar
-40
-50
-60
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
250 to 700 (375)
Size (D x H) [mm]
28.6 x 31.5
Power Supply [vDC]
28 ± 2
Weight [g]
80
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
BNC
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-40 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
28.0 @ 95 - 850 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
4.5 @ 95 - 850 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4R
file: sov1512.docm
Acoustic Emission Sensors - Specification
31 of 50
5.1.18
VS600-A1
VS600-A1
The VS600-A1 or -A2 is a passive piezoelectric AE-sensor. Its frequency response is characterized by a
peak at 600 kHz where it exhibits a resonance. It is a small foot-print AE-sensor with a threaded housing
and a top connector. The VS600-A* is intended for screwing it into a holding mechanism. It is suitable for
monitoring the crimping process.
-60
dB re -70
1V/µbar
-80
-90
-100
100
200
300
400
500
600
700
800
900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
390 to 850 (600)
Size (D x H) [mm]
7.0 x 13.5 (M7 x 0.75)
Capacity [pF]
109
Weight [g]
2.5
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +125
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC (top)
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4A1
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
32 of 50
5.1.19
VS600-A2
VS600-A2
The VS600-A1 or -A2 is a passive piezoelectric AE-sensor. Its frequency response is characterized by a
peak at 600 kHz where it exhibits a resonance. It is a small foot-print AE-sensor with a threaded housing
and a top connector. The VS600-A* is intended for screwing it into a holding mechanism. It is suitable for
monitoring the crimping process.
-60
dB re -70
1V/µbar
-80
-90
-100
100
200
300
400
500
600
700
800
900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
390 to 850 (600)
Size (D x H) [mm]
8.5 x 13.0 (M7 x 0.75 x 8.5)
Capacity [pF]
109
Weight [g]
3
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +125
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC (top)
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4A1
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
33 of 50
5.1.20
VS600-Z1
VS600-Z1
The VS600-Z1 is a passive piezoelectric AE-sensor with integrated cable. Its frequency response is
characterized by a peak at 600 kHz where it exhibits a resonance. Its small size makes it especially suited
for being mounted on small samples where mounting space is restricted.
-60
dB re -70
1V/µbar
-80
-90
-100
200
300
400
500
600
700
800
900
1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
550 to 730 (600)
Size (D x H) [mm]
4.75 x 5.8
Capacity [pF]
200 (incl. Cable)
Weight [g]
20
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-10 to +110
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMA/BNC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
AEP5, AEP3N
Sensor Cable
(integral)
Accessories
Preamplifier
Mounting Holder
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
34 of 50
5.1.21
VS600-Z2
VS600-Z2
The VS600-Z2 is a passive piezoelectric AE-sensor with integrated cable and full metal housing. Its
frequency response is characterized by a peak at 600 kHz where it exhibits a resonance. Its small size
makes it especially suited for being mounted on small samples where mounting space is restricted.
Additionally it is ideally suited for gluing to the sample because of the full metal housing.
-60
dB re -70
1V/µbar
-80
-90
-100
200
300
400
500
600
700
800
900
1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
400 to 800 (600)
Size (D x H) [mm]
4.75 x 5.3
Capacity [pF]
200 (incl. Cable)
Weight [g]
20
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +110
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMA/BNC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
AEP5, AEP3N
Sensor Cable
(integral)
Accessories
Preamplifier
Mounting Holder
12-2015
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Acoustic Emission Sensors - Specification
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5.1.22
VS700-D
VS700-D
The VS700-D is a passive piezoelectric AE-sensor with integrated cable. Its frequency response is
characterized by a series of relatively flat peaks at 350 kHz, 600 kHz and 750 kHz with a limited response
at 500 kHz. Its small size makes it especially suited for being mounted on small samples where mounting
space is restricted. It was intended for characterizing paper during tensile tests and its mounting
mechanism is optimized for this kind of task.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
150 to 800 (600 to 800)
Size (D x H) [mm]
6.3 x 10.0
Capacity [pF]
163 (incl. Cable)
Weight [g]
20
Integrated Preamplifier
No
Case Material
E-copper, tinned
Operating Temperature [°C]
-20 to +70
Wear Plate
Neodyne
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMA/BNC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
(integral)
Mounting Holder
integrated
Accessories
12-2015
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Acoustic Emission Sensors - Specification
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5.1.23
VS900-M
VS900-M
The VS900-M is a passive piezoelectric AE-sensor that has a broad frequency response. Its response is
characterized by two peaks at
190 kHz and 350 kHz with accompanying anti-resonances at 200 kHz and 400 kHz. Benefits of the VS900M are a high sensitivity over a broad frequency range with compromises regarding the flatness of
response. It combines a good response in the standard frequency - and high frequency range.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 900 (350)
Size (D x H) [mm]
20.3 x 14.3
Capacity [pF]
540
Weight [g]
22
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +100
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
Microdot
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V5
Mounting Holder
MAG4M
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
37 of 50
5.1.24
VS900-RIC
VS900-RIC
The VS900-RIC is a piezoelectric AE-sensor with integrated preamplifier. Its response is characterized by
two peaks at 190 kHz and 350 kHz with accompanying anti-resonances at 200 kHz and 400 kHz. Benefits
of the VS900-RIC are a high sensitivity over a broad frequency range with compromises regarding the
flatness of response. It combines a good response in the standard frequency - and high frequency range.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re -30
1V/µbar
-40
-50
-60
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 900 (350)
Size (D x H) [mm]
28.6 x 31.5
Power Supply [vDC]
28 ± 2
Weight [g]
80
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
BNC
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-40 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
26.9 @ 95 - 850 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
4.5 @ 95 - 850 kHz
Ingress Protection Rating
IP40
Sensor Cable
CBL-1-xM-V1
Accessories
Mounting Holder
12-2015
MAG4R
file: sov1512.docm
Acoustic Emission Sensors - Specification
38 of 50
5.2
Watertight AE-sensors
5.2.1
VS150-K2
VS150-K2
The VS150-K2 is a passive piezoelectric AE-sensor with integral cable. Its frequency response is
characterized by a peak at 150 kHz where it exhibits a resonance. It is suitable for almost all AE
application. The VS150-K2 has a full metal housing and a watertight cap. It is rated IP68 and watertight up
to 10 bar (maximum water depth of 100 m). The mechanical design makes it especially suited for
adhesively mounting it to a test object.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
20.3 x 22
Capacity [pF]
350
Weight [g]
56
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-40 to +100
Wear Plate
Stainless Steel (1.4571/
1.4404)
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC @ 1 m RG178 Cable
Ingress Protection Rating
IP68, max. 10 bar
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4H
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
39 of 50
5.2.2
VS150-WIC-V01
VS150-WIC-V01
The VS150-WIC is a piezoelectric AE-sensor with integrated preamplifier. Its frequency response is
characterized by a peak at 150 kHz where it exhibits a resonance. The VS150-WIC is rated watertight up to
60 bar of water pressure. It is suitable for almost all AE application and especially suited for wet
environments or for on-site monitoring of underwater installations.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re -30
1V/µbar
-40
-50
-60
0
50 100 150 200 250 300 350 400 450 500 550 600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
32.0 x 48.0
Power Supply [vDC]
28 ± 2
Weight [g]
184
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
LEMO 03 Series
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-40 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
25.2 @ 95 - 300 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
5.0 @ 95 - 300 kHz
Ingress Protection Rating
IP68, max. 60 bar (with
connected cable)
Sensor Cable
CBL-1-xM-V11
Accessories
Mounting Holder
12-2015
MAG4W-V1
file: sov1512.docm
Acoustic Emission Sensors - Specification
40 of 50
5.2.3
VS375-WIC-V01
VS375-WIC-V01
The VS375-WIC is a piezoelectric AE-sensor with integrated preamplifier. Its frequency response is
characterized by a peak at 375 kHz where it exhibits a resonance. The VS375-WIC is rated watertight up to
60 bar of water pressure. Its frequency response bridges the gap between standard frequency range and
high frequency range. The VS375-WIC is suited for wet environments or for on-site monitoring of
underwater installations.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re -30
1V/µbar
-40
-50
-60
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
250 to 700 (375)
Size (D x H) [mm]
32.0 x 48.0
Power Supply [vDC]
28 ± 2
Weight [g]
181
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
LEMO 03 Series
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-40 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
28.0 @ 95 - 850 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
4.5 @ 95 - 850 kHz
Ingress Protection Rating
IP68, max. 60 bar (with
connected cable)
Sensor Cable
CBL-1-xM-V11
Accessories
Mounting Holder
12-2015
MAG4W-V1
file: sov1512.docm
Acoustic Emission Sensors - Specification
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5.2.4
VS900-WIC-V01
VS900-WIC-V01
The VS900-WIC-V01 is a piezoelectric AE-sensor with integrated preamplifier. Its response is
characterized by two peaks at 190 kHz and 350 kHz with accompanying anti-resonances at 200 kHz and
400 kHz. Benefits of the VS900-WIC-V01 are a high sensitivity over a broad frequency range with
compromises regarding the flatness of response. It combines a good response in the standard frequency and high frequency range. The VS900-WIC is rated water tight up to 60 bar of water pressure. suited for
wet environments or for on-site monitoring of underwater installations.
The integrated preamplifier has 34 dB gain and supports pulse through for automatic sensor testing.
-20
dB re -30
1V/µbar
-40
-50
-60
0
100 200 300 400 500 600 700 800 900 1000
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 900 (350)
Size (D x H) [mm]
32.0 x 48.0
Power Supply [vDC]
28 ± 2
Weight [g]
181
Typ. Power [W]
0.56 / 2.5 @ Signal 0% /
100%
Case Material
Stainless Steel (1.4571/
1.4404)
Integrated Preamplifier
Yes
Wear Plate
Ceramics
Preamplifier Gain [dB]
34
Connector
LEMO 03 Series
Pulse Through
Yes
Shield Cross-Talk [dB]
< -80
Operating Temperature [°C]
-40 to +85
Typ. Noise (max. 1/s) [dBAE Peak]
26.9 @ 95 - 850 kHz
Vibration – Sinus Sweep
2 Oct/Min, 5 to 50 Hz, 20 g
Typ. Noise [µVRMS]
4.5 @ 95 - 850 kHz
Ingress Protection Rating
IP68, max. 60 bar (with
connected cable)
Sensor Cable
CBL-1-xM-V11
Accessories
Mounting Holder
12-2015
MAG4W-V1
file: sov1512.docm
Acoustic Emission Sensors - Specification
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5.3
High temperature AE-sensor
5.3.1
VS160-NS
VS160-NS
The VS160-NS is a passive piezoelectric AE-sensor suitable for hot environments (up to 180°C). Its
frequency response is characterized by a peak at 160 kHz where it exhibits a resonance. It is suitable for
almost all AE application and especially suited for integrity inspection of metallic pressure vessels.
-60
dB re -70
1V/µbar
-80
-90
-100
0
100
200
300
400
500
600
f/kHz
Technical Specification
Frequency Range (fPeak) [kHz]
100 to 450 (150)
Size (D x H) [mm]
20.3 x 14.3
Capacity [pF]
350
Weight [g]
22
Integrated Preamplifier
No
Case Material
Stainless Steel (1.4571/
1.4404)
Operating Temperature [°C]
-50 to +180
Wear Plate
Ceramics
Vibration – Sinus Sweep
2 Oct/Min, 5 to 180 Hz, 40 g
Connector
SMC
Ingress Protection Rating
IP40
Shield Cross-Talk [dB]
< -80
Preamplifier
AEP5, AEP3N
Sensor Cable
CBL-1-1M2-V15
Mounting Holder
MAG4NS
Accessories
12-2015
file: sov1512.docm
Acoustic Emission Sensors - Specification
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5.4
AE-sensors for hazardous areas
Vallen Systeme offers an intrinsically safe product family (ISAFE3). This product family is ATEX certified and
consists not only of a family of AE-sensors but also of special signal isolator to fulfil all safety requirements
for hazardous areas of zone 0, zone 1 or zone 2. For more details please see the ‘Vallen ISAFE3 Operation
Manual’ or contact us at info@vallen.de.
5.5
Third party AE-sensors with longer delivery time
5.5.1
AE1045S
The AE1045S is a wideband AEsensor. Comes with a calibration
sheet from absolute reciprocal
velocity calibration showing a very
flat frequency response from 0.1 to
1.5 MHz.
Response measured with 1 m
cable (90 pF). 4 dB higher
sensitivity with 10 cm cable due to
the low internal capacity (90 pF).
5.5.2
AE2045S
The AE2045S is a wideband AEsensor. Comes with a calibration
sheet from absolute reciprocal
velocity calibration showing a very
flat frequency response from 0.2 to
2.5 MHz.
Response measured with 1 m
cable (90pF). 3 dB higher
sensitivity with 10 cm cable due to
the low internal capacity (140 pF).
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5.5.3
AE104A
AE sensor with a relatively flat
frequency response between 100
and 400 kHz. Frequency curve
measured with 1 m cable (90 pF).
6 dB sensitivity increase with
10 cm cable.
5.5.4
AE105A
AE-sensor for high frequency
applications. Frequency curve
measured with 1 m cable (90 pF).
5 dB sensitivity increase with
10 cm cable.
5.5.5
AE144A
AE-sensor with a relatively flat
frequency response between 100
and 500 kHz. Frequency curve
measured with 1 m cable (90pF).
7dB sensitivity increase with 10cm
cable.
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Acoustic Emission Sensors - Specification
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5.5.6
AE204A
AE-sensor with a relatively flat
response between 180 and 700
kHz. Frequency curve measured
with 1 m cable. (90pF). 6dB
sensitivity increase with 10cm
cable.
5.5.7
M31
Very small sensor for AE tests on
small specimens. For a frequency
range from about 300 kHz to 800
kHz. Frequency curve measured
with 0.5 m integral cable.
5.5.8
M58
Very small sensor for AE testing of
small specimens or for high
frequency applications. Frequency
curve measured with 1 m integral
cable.
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6
Warranty
Warranty period for AE-sensors is 3 months, provided the AE-sensors have been correctly
handled. Defects caused by mechanical shock are not covered by the warranty. Except of the
replacement of defective AE-sensors, we disclaim all other warranties. We warrant that the
goods as delivered will conform to the specifications. On notification during the warranty period
defective items will be replaced, free of costs and within a reasonable time. If transportation
should become necessary, the customer has to provide the permits for export and re-import of
replacement parts and bear the costs of transportation. We shall not be liable for any direct,
indirect or consequential damage arising out of the use of or inability to use delivered AEsensors.
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7
Appendix
7.1
AE-sensor handling
Vallen Systeme AE-sensors are built for tough field testing conditions. Nevertheless AE-sensors
should be handled with care and should not be dropped or subject to excessive mechanical
force.
Please make sure that the metal parts of the AE-sensor are electrically isolated against the test
object´s surface. If full metal AE-sensor cases are used (-L, -A1, -A2 and -Z2 case) and the
surface of the test object is a conductive material use e.g. Flashbreaker® tape as isolating
interface.
7.2
Mounting of AE-sensors
An AE-sensor needs to be mounted firmly to the surface of the structure under test. The
mounting shall assure that an AE-sensor cannot move during the test and ensure that
transmission losses through the interface between test object surface and sensitive face of the
AE-sensor is minimal. Methods for mounting can be categorized into two groups: compression
mounts and adhesive mounts.
7.2.1
Compression mount
A compression mount holds the AE-sensor in contact with the surface of the test object through
the use of pressure.
One of the most popular compression mount methods is using magnetic holders. Magnetic
holders (also called magnetic locks) can be used if the test object is ferromagnetic. The
compressive force is delivered via the springs attached to the magnet(s). Magnetic holders for
Vallen AE-sensors can be found in ‘Accessories for AE Systems’.
Caution: removing AE-sensors
When removing AE-sensors from the structure use the handles of the magnetic holders to slide
off the magnet and do not pull on a cable. Pulling cables may result in their damage.
Other popular mounting aids are clamps, adhesive tape or elastic bands. It is strongly advised
to use couplant together with compression mounts in order to reduce transmission losses and
effectively increase AE-sensor’s sensitivity.
7.2.2
Adhesive mount (bonding)
An AE-sensor may also be bonded directly to the object’s surface. Care should be taken
choosing the right adhesive which should not attack the surface it is applied to. The adhesive
will also act as a couplant.
Note:
Bonding is a rather rigid way of mounting an AE-sensor to a surface. Surface deformation due
to mechanical loading or thermal expansion may cause the bond to crack. These cracks are a
source of unwanted AE-signals.
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Caution: removing bonded AE-sensor with ceramic wear plate
Most sensors have a ceramic wear plate glued in front of the sensitive area to protect the
piezoelectric element. Irreparable damage could be introduced to the ceramic wear plate if this
bond breaks before the mounting adhesive during the attempt to remove the sensor from the
test object. Similarly the test object (e.g. composite materials) could get damaged when
removing a sensor.
The most appropriate way of removing a bonded AE-sensor is to move the AE-sensor sideways
to generate shear stress in the bond interface or tab the AE-sensor gently on the side until it
comes off.
Special Feature: AE-sensors suitable for bonding
Vallen Systeme supplies also full metal housing AE-sensors (e.g. VS600-Z2, VS150-L) which are
particularly suitable for bonding.
7.3
Usage of couplant
A couplant applied between surface of test object and sensitive face of an AE-sensor reduces
the transmission losses of elastic wave energy entering the AE-sensor, effectively increasing
the sensitivity of the sensor. A couplant should be selected under consideration of the
environment (e.g. temperature, pressure, composition of atmosphere or liquid environment).
Most important a couplant should be chemically compatible to the test object’s surface (e.g. not
corroding).
A couplant should be applied with the thinnest practical layer. No voids or entrapped air
inclusions should be present. Thick layers of couplant or unevenness of it can reduce the
sensitivity of an AE-sensor.
Applying couplant:
A practical way of applying couplant is to place a small amount of couplant on the center of the
sensitive face of the AE-sensor. Carefully press the AE-sensor onto the surface of the object
under test. The couplant should spread evenly from the center to the outside and ooze a bit out
under the AE-sensor.
Most AE-sensors are sensitive to normal surface motion, only. Hence the viscosity of the
couplant is not of significant importance under normal conditions. Most liquids or greases will
work when they wet the surfaces of both the AE-sensor and the object under test. See
document “Accessories for Acoustic Emission Systems” for our couplant product range.
7.4
AE-Sensor verification
We recommend verifying every AE-sensor in certain intervals depending on its usage and
application. This verification is especially recommended if an AE-sensor has been dropped,
exposed to high temperatures or in any case when the AE-sensor response give reasons to
doubt the integrity of it. Vallen Systeme is able to verify most AE sensors available on the
market. The verification tool called Vallen Sensor Tester (VST) is also available for purchase.
The VST generates frequency response graphs which can be used to identify response
changes over time. See document “Accessories for Acoustic Emission Systems” for more
information.
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7.4.1
Frequency Response Measurement
All Vallen AE-sensors come with a test certificate. The test certificate shows the frequency
response of the specific AE-sensor to a reproducible excitation. When comparing the original
certificate with the result of a comparative test at a later date possible AE-sensor response
changes can be identified. Some aspects of AE-sensor response are not addressed:
7.4.2
•
The type of wave (pulse or continuous) may affect the AE-sensor output, especially with
resonant AE-sensors. AE-sensor under test is coupled face-to-face to an emitter. Emitter is
driven by a continuous sine wave. Response of AE-sensor is recorded at different
frequencies and plotted in diagram.
•
The surface displacement caused by a wave is three dimensional, the electrical AE signal
is one dimensional. How an AE-sensor performs with respect to each displacement
direction is not identified in a frequency response curve.
•
The AE-sensor’s response will be affected by the structure on which it is mounted. Even
when the same setup is used, care must be taken to align the AE-sensor and emitter
properly to maintain relative reproducibility.
Pressure Excitation
With this testing method the exciting displacement is uniform over the whole crystal face. This is
realized by coupling the AE-sensor under test face-to-face with a wideband ultrasonic emitter.
The emitter is then stimulated by a continuous sine wave, which frequency is swept over the
range of interest. The RMS signal level of the AE-sensor under test is plotted in dB versus
frequency, whereby 0 dB refers to a AE-sensor output of 1 V at an excitation of 1 µbar.
This testing method is fast, easy to reproduce (e.g. by the Vallen Sensor Tester, VST) and most
standard test certificates are made by this method.
This document shows pressure excitation results.
Customers having the Vallen Sensor Tester (VST) can qualitatively reproduce the frequency
response curves with the following settings:
Pressure Excitation:
Output Voltage
0.1 VRMS (0.05 VRMS if preamplifier gain > 40 dB)
Offset
-114 dB – external gain (+ 6 dB if preamplifier gain > 40 dB)
Cable length used
RG178m 1.2 m, if no other length is stated for the frequency
curve.
Olympus V103 (ultrasonic wideband Sensor) is used as emitter. AE-sensor under test is
coupled face-to-face to emitter using a suited couplant (e.g. light machine oil).
For the VS30-V and VS75-V an Olympus V101 is used instead of the V103. The other settings
can be seen from the legends in the frequency curves.
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