GB2238120A - Corrosion monitoring using a piezo-electric crystal on a solid probe - Google Patents
Corrosion monitoring using a piezo-electric crystal on a solid probe Download PDFInfo
- Publication number
- GB2238120A GB2238120A GB8923760A GB8923760A GB2238120A GB 2238120 A GB2238120 A GB 2238120A GB 8923760 A GB8923760 A GB 8923760A GB 8923760 A GB8923760 A GB 8923760A GB 2238120 A GB2238120 A GB 2238120A
- Authority
- GB
- United Kingdom
- Prior art keywords
- crystal
- piezo
- probe
- corrosion monitoring
- electric crystal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 23
- 239000000523 sample Substances 0.000 title claims abstract description 18
- 238000005260 corrosion Methods 0.000 title claims abstract description 12
- 230000007797 corrosion Effects 0.000 title claims abstract description 12
- 238000012544 monitoring process Methods 0.000 title claims abstract description 11
- 239000007787 solid Substances 0.000 title claims description 7
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 claims description 3
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 3
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims 1
- 238000012806 monitoring device Methods 0.000 abstract 1
- 229910001220 stainless steel Inorganic materials 0.000 abstract 1
- 239000010935 stainless steel Substances 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
- G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02854—Length, thickness
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
An on-line corrosion monitoring apparatus comprises a thickness measuring probe having a piezo-electric crystal 7 bonded to a stainless steel stud 4. The stud 4 is threaded or grooved, 5 to reduce noise and it can have a slot 6 to produce a first echo signal. The stud is welded to equipment 3 under test and the crystal is connected via a cable 9 to a monitoring device. A second echo signal is produced by reflection from an inner surface 10 of the equipment 3 and corrosion on the surface 10 is detected by changes in the time interval between first and second echo signals. <IMAGE>
Description
Corrosion Monitoring
The present invention concerns on-line corrosion monitoring of plant and equipment.
It is known practice to use ultrasonic devices for the measurement of metal thickness in a variety of different industries. Generally however measurements are taken when the components are in a "shut-down" state for servicing and maintenance operations. In such operations the ultrasonic device is moved manually over the component being tested and is removably coupled to the component by a "coupling gel".
The aim of the present invention is to utilise ultrasonic devices for the continuous monitoring of plant and equipment during operation and without need to resort to shut-down.
According to one aspect of the present invention a method for on-line corrosion monitoring of plant and equipment comprises fixedly securing at one end a solid probe having a grooved or threaded exterior to a surface to be monitored, bonding an inorganic piezo-electric crystal to the opposite end of the probe, arranging a housing about the crystal and connecting the crystal to a measuring instrument located at a position remote from the crystal.
According to another aspect of the present invention an apparatus for on-line corrosion monitoring of plant and equipment comprises a solid probe having a grooved or threaded exterior adapted to be fixedly secured at one end to a surface to be monitored, an inorganic piezo-electric crystal bonded to he opposite end of the probe, a protective housing about the crystal and cable means for connecting the crystal to remote instrumentation.
Conveniently, the inorganic piezo-electric crystal comprises lithium niobate or lead zirconate titanate.
Preferably, the housing is filled with a gas or gas mixture which ensures that the piezo-electric crystal and its electrical connections do not deteriorate during use.
The cable means can be a ceramic insulated metal cable.
Conveniently, a slot for a first echo signal can be machined in the probe adjacent the end thereof fixedly secured to the surface to be monitored.
The invention will be described further, by way of example, with reference to the accompanying diagrammtic drawing which shows a solid coupled probe fixed to a wall of a vessel.
A probe 1 is fixedly secured by a weld 2 to wall 3 of a plant or equipment. Thus the wall 3 can be a pipe or the wall of a vessel. The probe comprises a solid stud 4, conveniently a steel stud, having a thread or groove 5 on its exterior surface and extending between the ends of the stud. A slot 6 can be formed in the stud adjacent the weld 2. A piezo-electric crystal 7, conveniently lithium niobate or lead zirconate titanate is bonded to the end of the stud as by brazing or soldering for example. A protective housing 8 which can be filled with an inert atmosphere, is placed over the crystal, the housing 8 fitting on to the end of the stud.
The crystal 7 is connected by mineral insulated cable 9 to instrumentation (not shown) positioned at a location remote from the probe.
The probe is intended for continuous on-line operation and is permanently fixed in its position of use. The probe monitors corrosion at the interior surface 10 of the wall 3 by noting changes in the thickness of the wall. The slot 6 in the stud provides a first echo signal, there being no signal from the weld 2, and reflection at the surface 10 provides a further signal. Changes in time intervals between the signals as recorded at the measuring instrumentation provide a measurement of corrosion at the inner surface 10. The grooved or threaded exterior of the stud serves to reduce noise.
The probe is suited for monitoring plant or equipment having difficulty of access or hazardous to operating personnel.
Claims (5)
1. A method for on-line corrosion monitoring of plant and equipment comprising fixedly securing at one end a solid probe having a grooved or threaded exterior to a surface to be monitored, bonding an inorganic piezo-electric crystal to the opposite end of the probe, arranging a housing about the crystal and connecting the crystal to a measuring instrument located at a position remote from the crystal.
2. An apparatus for on-line corrosion monitoring of plant and equipment comprising a solid probe having a grooved or threaded exterior adapted to be fixedly secured at one end to a surface to be monitored, an inorganic piezo-electric crystal bonded to the opposite end of the probe, a protective housing about the crystal and cable means for connecting the crystal to remote instrumentation.
3. An apparatus as claimed in claim 2 in which the piezo-electric crystal comprises lithium niobate or lead zirconate titanate.
4. An apparatus as claimed in claim 2 or 3 in which the housing is filled with an inert gas.
5. A method and apparatus for on-line corrosion monitoring substantially as herein described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8923760A GB2238120B (en) | 1989-10-21 | 1989-10-21 | Corrosion monitoring |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8923760A GB2238120B (en) | 1989-10-21 | 1989-10-21 | Corrosion monitoring |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8923760D0 GB8923760D0 (en) | 1989-12-06 |
| GB2238120A true GB2238120A (en) | 1991-05-22 |
| GB2238120B GB2238120B (en) | 1993-09-08 |
Family
ID=10664964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8923760A Expired - Fee Related GB2238120B (en) | 1989-10-21 | 1989-10-21 | Corrosion monitoring |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2238120B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6490927B2 (en) * | 2000-12-22 | 2002-12-10 | Honeywell International Inc. | Method for detecting multiple types of corrosion |
| CN103575805A (en) * | 2012-08-07 | 2014-02-12 | 济南大学 | Ultrasonic monitoring sensor for corrosion of steel bar in concrete and application method of sensor |
| WO2014193808A1 (en) * | 2013-05-28 | 2014-12-04 | Dow Global Technologies Llc | Methods and systems for measuring corrosion in-situ |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB901195A (en) * | 1960-03-11 | 1962-07-18 | Clevite Corp | Electromechanical transducers |
| EP0232613A2 (en) * | 1986-01-27 | 1987-08-19 | The Babcock & Wilcox Company | Detection of hydrogen damage in boiler tubes |
| GB2201318A (en) * | 1987-02-12 | 1988-08-24 | Udi Group Ltd | Electromechanical transducer |
| GB2212919A (en) * | 1987-11-25 | 1989-08-02 | Ishikawajima Harima Heavy Ind | Probe for an ultrasonic flaw detector welded to a support |
-
1989
- 1989-10-21 GB GB8923760A patent/GB2238120B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB901195A (en) * | 1960-03-11 | 1962-07-18 | Clevite Corp | Electromechanical transducers |
| EP0232613A2 (en) * | 1986-01-27 | 1987-08-19 | The Babcock & Wilcox Company | Detection of hydrogen damage in boiler tubes |
| GB2201318A (en) * | 1987-02-12 | 1988-08-24 | Udi Group Ltd | Electromechanical transducer |
| GB2212919A (en) * | 1987-11-25 | 1989-08-02 | Ishikawajima Harima Heavy Ind | Probe for an ultrasonic flaw detector welded to a support |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6490927B2 (en) * | 2000-12-22 | 2002-12-10 | Honeywell International Inc. | Method for detecting multiple types of corrosion |
| CN103575805A (en) * | 2012-08-07 | 2014-02-12 | 济南大学 | Ultrasonic monitoring sensor for corrosion of steel bar in concrete and application method of sensor |
| WO2014193808A1 (en) * | 2013-05-28 | 2014-12-04 | Dow Global Technologies Llc | Methods and systems for measuring corrosion in-situ |
| US10041911B2 (en) | 2013-05-28 | 2018-08-07 | Dow Global Technologies Llc | Methods and systems for measuring corrosion in-situ |
| US10962505B2 (en) | 2013-05-28 | 2021-03-30 | Dow Global Technologies Llc | Methods and systems for measuring corrosion in-situ |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8923760D0 (en) | 1989-12-06 |
| GB2238120B (en) | 1993-09-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19971021 |