CA1162987A - Method and means for detecting magnetic deposits in heat exchanger and the like - Google Patents
Method and means for detecting magnetic deposits in heat exchanger and the likeInfo
- Publication number
- CA1162987A CA1162987A CA000354272A CA354272A CA1162987A CA 1162987 A CA1162987 A CA 1162987A CA 000354272 A CA000354272 A CA 000354272A CA 354272 A CA354272 A CA 354272A CA 1162987 A CA1162987 A CA 1162987A
- Authority
- CA
- Canada
- Prior art keywords
- probe
- magnetic
- deposits
- heat exchanger
- tube
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
METHOD AND MEANS FOR DETECTING MAGNETIC DEPOSITS IN HEAT
EXCHANGER AND THE LIKE
Abstract of the Disclosure Deposits of magnetite on coils in a heat exchanger of a steam generator are detected by measuring the magnetic reluctance within the coils. A probe for measuring the reluctance includes a magnetic core, an excitation coil wound on the core, and a magnetic flux detector such as a Hall generator. Changes in flux density established by the excitation coil are detected by the Hall generator, thus indicating the presence of magnetite deposits.
EXCHANGER AND THE LIKE
Abstract of the Disclosure Deposits of magnetite on coils in a heat exchanger of a steam generator are detected by measuring the magnetic reluctance within the coils. A probe for measuring the reluctance includes a magnetic core, an excitation coil wound on the core, and a magnetic flux detector such as a Hall generator. Changes in flux density established by the excitation coil are detected by the Hall generator, thus indicating the presence of magnetite deposits.
Description
A- 3 4 7 ~"~ JT/HKW
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MET}IOD AND MEANS E'OR DETECTING MP.GNETIC DEPOSITS IN
HEAT EXCHANGER AND THE L:[:KE
. _ _ This invention relates generally to inspection equipment for tubular products such as coils in heat exchangers, and more particularly the invention relates to an improved m~thod and means for detecting deposits of magnetite in ; S heat exchangers.
Heat eXchan~ers such as used in connection with steam driven electric power generators are subjected to very high temperatures and pressures. Further, deposits of ;~ 10 impurities from fluids used in the heat exchangers tend to build up on the tubes and support structure in the heat exchanger which can lead to tube thinning and crack-ing. Thus, the tubes must be periodically inspected to insure safe operation.
,~ 15 In particular, steam generator units associated with nuclear reactor plants can experience tube denting in the support plate region due to a buildup of deposits containing magnetite. Heretofore, no single technique has been developed which is capahle of predictin~ the presence of magnetite buildup in the crevice gap region of steam generators, although attempts have been made to detect the presence of magnetite by eddy current, acoustic, and radiographic techniques. Oth~r attempts ~. .
, - , ' .
: '
~ lG2~
MET}IOD AND MEANS E'OR DETECTING MP.GNETIC DEPOSITS IN
HEAT EXCHANGER AND THE L:[:KE
. _ _ This invention relates generally to inspection equipment for tubular products such as coils in heat exchangers, and more particularly the invention relates to an improved m~thod and means for detecting deposits of magnetite in ; S heat exchangers.
Heat eXchan~ers such as used in connection with steam driven electric power generators are subjected to very high temperatures and pressures. Further, deposits of ;~ 10 impurities from fluids used in the heat exchangers tend to build up on the tubes and support structure in the heat exchanger which can lead to tube thinning and crack-ing. Thus, the tubes must be periodically inspected to insure safe operation.
,~ 15 In particular, steam generator units associated with nuclear reactor plants can experience tube denting in the support plate region due to a buildup of deposits containing magnetite. Heretofore, no single technique has been developed which is capahle of predictin~ the presence of magnetite buildup in the crevice gap region of steam generators, although attempts have been made to detect the presence of magnetite by eddy current, acoustic, and radiographic techniques. Oth~r attempts ~. .
, - , ' .
: '
2 ~
at detecting the presence of magnetite have been through the use o~
induced mechanical vibrations in the -tubes of the heat exchanger.
An object o~ the invention is a probe for magnetically detecting the presence o~ magnetite deposits in a heat exchanger.
Briefly, in accordance with the invention, there is provided a probe for detecting deposits o~ magnetite in steam generator tubes and the like comprising a magnetic core, an excitation coil wound on said core ~or establishing a magnetic ` field, a variable current source interconnected for energizing said coil, a magnetic ~lux density detector for detecting magnetic flux density, and a Gauss meter interconnected with said detector for measuring magnetic flux changes.
B~ energizing the coil and moving the probe through a tubular product such as a heat exchanger, deposits of magnetite can be detected and crevice gap clearance can be measured by detecting the changes in magnetic flux density.
The invention and objects and features thereof will be more readily apparent from the following detailed description and appended claims when taken with the drawings.
In the drawings, Figure 1 is a section view of a heat exchanger such as used in a nuclear reactor steam system.
Figure 2 is an enlarged view of a portion of a tube and support plate in the heat exchanger of Figure 1.
Figure 3 is a functional block diagram of equipment ~ r ~. . . ..
.
. ~ .
~ 1~2~7
at detecting the presence of magnetite have been through the use o~
induced mechanical vibrations in the -tubes of the heat exchanger.
An object o~ the invention is a probe for magnetically detecting the presence o~ magnetite deposits in a heat exchanger.
Briefly, in accordance with the invention, there is provided a probe for detecting deposits o~ magnetite in steam generator tubes and the like comprising a magnetic core, an excitation coil wound on said core ~or establishing a magnetic ` field, a variable current source interconnected for energizing said coil, a magnetic ~lux density detector for detecting magnetic flux density, and a Gauss meter interconnected with said detector for measuring magnetic flux changes.
B~ energizing the coil and moving the probe through a tubular product such as a heat exchanger, deposits of magnetite can be detected and crevice gap clearance can be measured by detecting the changes in magnetic flux density.
The invention and objects and features thereof will be more readily apparent from the following detailed description and appended claims when taken with the drawings.
In the drawings, Figure 1 is a section view of a heat exchanger such as used in a nuclear reactor steam system.
Figure 2 is an enlarged view of a portion of a tube and support plate in the heat exchanger of Figure 1.
Figure 3 is a functional block diagram of equipment ~ r ~. . . ..
.
. ~ .
~ 1~2~7
3-useful in the method of detecting magnetic deposits in accordance with the present invention.
Figure 4 is a side view in section of a tube and support plate and a probe for detecting deposits of magnetite in accordance with the invention.
Referriny now to the drawings, Figure 1 is a section view of a nuclear reactor heat exchan~er in which pri-mary fluid from the reactor flows into inlet 10, through tubes 12, and exits through outlet 14. Feed water for steam enters through inlet 16 and flows downwardly into contact with tubes~12, and the exchange o heat from tubes 12 to the water creates steam which exits through outlet 18 to drive a tur~ine. The heat exchanger also conventionally includes a moisture separator 20 and swirl-vane moisture separators 22.
The tubes 12 which interconnect the primary fluid from the inlet 10 to the outlet 14 are supported within the exchanger by a support structure 24 including plate 26 which supports the tube~ 12. As above indicated, de-posits of magnetite form in the heat exchanger, and the buildup of ma~netite in the crevice gap region where the tubes are supported by plates 26 can create denting of the tubes which can lead to thinning and cracking of the tube walls, Figure 2 is an enlarged view of the crevice gap region within circle 30 of Figure 1 and shows the tube 32 pass~
ing through support plate 34 with the buildup of magne-tite 36 in the crevice between tube 32 and plate 34. In an acute case, the buildup of magnetite fills the crevice gap and causes denting of the tube which eventuallY can cause cracking and thinning of the tube walls. Hereto-fore, no adequate inspection technique has been known -, which will predict the presence of magnetite buildup ~ ~2~3~7 in the crevice gap region as shown in Figure 2, Figure 3 is a functional block diagram of equipment for detecting ma~netite deposits in acccrdance with the present invention. The equipment includes a probe com-prising a bobbin 50 which supports a magnetic core 52 with an excitation coil 54 wound on the core. Mounted on the bobbin 50 is a flux detector 56 which preferably comprises a Hall generator.
A current source 58 is interconnected to energize the coil 54, and a Gauss meter 60 is interconnected with the Hall generator 56 for detecting magnetic flux densities.
The output of the Gauss meter may be interconnected with a digital oscilloscope 62 and an X-Y plotter 64.
The probe is mounted on a suitable carrier such as a Nylon tube, and the carrier and probe are pushed through the tube of the heat exchanger by means of a suitable motor drive 66. Thus, the energized coil sets up a mag-netic flux pattern, and as the probe is pushed through the tube changes in the flux pattern due to the presence of magnetite in close proximity to the tube causes an increase in flux density which is detected by the Hall ; 25 generator and measured by the Gauss meter 60. Accord-ingly, the presence and location of deposits of magne-tite can be established~
Figure 4 is a cross section of support plate 80 and tube ` 30 82 extending therethrough with a probe shown generally at 84 and probe carrier 86 positioned within tube 82.
Typically, the support plate 80 comprises carbon steel and tub~ 82 comprises Inconel. Probe 84 comprises a soft iron core 88 which is mounted between two non-magnetic guide rings 90 with the coil 92 wound on core 88. The two guide rings are held together by a bolt 94 with nut 96 fastened on cne end of bolt g4 and the .
-' ,, , .
~. . . .
' other end of the bolt threadably engaging the tube 86.
The Hall generator is mounted on one of the rings in close proximity to the tube wall. Carrier 86 typically , comprises a non magnetic tube such as Nylon~ and the wire interconnections to the coil and to the Hall generator are placed within tube 86.
I~hile the invention has been described with reference to a specific embodiment, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modiiications and applications may occur to those skilled in the ar~ without departing from the true spirit and scope of the invention as de-fined by the appended claims.
~ r/~
Figure 4 is a side view in section of a tube and support plate and a probe for detecting deposits of magnetite in accordance with the invention.
Referriny now to the drawings, Figure 1 is a section view of a nuclear reactor heat exchan~er in which pri-mary fluid from the reactor flows into inlet 10, through tubes 12, and exits through outlet 14. Feed water for steam enters through inlet 16 and flows downwardly into contact with tubes~12, and the exchange o heat from tubes 12 to the water creates steam which exits through outlet 18 to drive a tur~ine. The heat exchanger also conventionally includes a moisture separator 20 and swirl-vane moisture separators 22.
The tubes 12 which interconnect the primary fluid from the inlet 10 to the outlet 14 are supported within the exchanger by a support structure 24 including plate 26 which supports the tube~ 12. As above indicated, de-posits of magnetite form in the heat exchanger, and the buildup of ma~netite in the crevice gap region where the tubes are supported by plates 26 can create denting of the tubes which can lead to thinning and cracking of the tube walls, Figure 2 is an enlarged view of the crevice gap region within circle 30 of Figure 1 and shows the tube 32 pass~
ing through support plate 34 with the buildup of magne-tite 36 in the crevice between tube 32 and plate 34. In an acute case, the buildup of magnetite fills the crevice gap and causes denting of the tube which eventuallY can cause cracking and thinning of the tube walls. Hereto-fore, no adequate inspection technique has been known -, which will predict the presence of magnetite buildup ~ ~2~3~7 in the crevice gap region as shown in Figure 2, Figure 3 is a functional block diagram of equipment for detecting ma~netite deposits in acccrdance with the present invention. The equipment includes a probe com-prising a bobbin 50 which supports a magnetic core 52 with an excitation coil 54 wound on the core. Mounted on the bobbin 50 is a flux detector 56 which preferably comprises a Hall generator.
A current source 58 is interconnected to energize the coil 54, and a Gauss meter 60 is interconnected with the Hall generator 56 for detecting magnetic flux densities.
The output of the Gauss meter may be interconnected with a digital oscilloscope 62 and an X-Y plotter 64.
The probe is mounted on a suitable carrier such as a Nylon tube, and the carrier and probe are pushed through the tube of the heat exchanger by means of a suitable motor drive 66. Thus, the energized coil sets up a mag-netic flux pattern, and as the probe is pushed through the tube changes in the flux pattern due to the presence of magnetite in close proximity to the tube causes an increase in flux density which is detected by the Hall ; 25 generator and measured by the Gauss meter 60. Accord-ingly, the presence and location of deposits of magne-tite can be established~
Figure 4 is a cross section of support plate 80 and tube ` 30 82 extending therethrough with a probe shown generally at 84 and probe carrier 86 positioned within tube 82.
Typically, the support plate 80 comprises carbon steel and tub~ 82 comprises Inconel. Probe 84 comprises a soft iron core 88 which is mounted between two non-magnetic guide rings 90 with the coil 92 wound on core 88. The two guide rings are held together by a bolt 94 with nut 96 fastened on cne end of bolt g4 and the .
-' ,, , .
~. . . .
' other end of the bolt threadably engaging the tube 86.
The Hall generator is mounted on one of the rings in close proximity to the tube wall. Carrier 86 typically , comprises a non magnetic tube such as Nylon~ and the wire interconnections to the coil and to the Hall generator are placed within tube 86.
I~hile the invention has been described with reference to a specific embodiment, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modiiications and applications may occur to those skilled in the ar~ without departing from the true spirit and scope of the invention as de-fined by the appended claims.
~ r/~
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A probe for detecting deposits of magnetite in steam generator tubes and the like comprising a magnetic core, an excitation coil wound on said core for establishing a magnetic field, a variable current source interconnected for energizing said coil, a magnetic flux density detector for detecting magnetic flux density, and a Gauss meter interconnected with said detector for measuring magnetic flux changes.
2. A probe as defined by claim 1 wherein said detector comprises a Hall generator.
3. A probe as defined by claim 2 and further including means for pushing said probe through a tube.
4. A probe as defined by claim 3 wherein said means for pushing comprises a non-magnetic tube.
5. A probe as defined by claim 3 and further including a current source interconnected for energizing said coil and a Gauss meter interconnected with said Hall generator for measuring magnetic flux changes.
6. A probe as defined by claim 3 and further including non-magnetic guide rings for supporting said magnetic core.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US4972379A | 1979-06-18 | 1979-06-18 | |
| US049,723 | 1979-06-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1162987A true CA1162987A (en) | 1984-02-28 |
Family
ID=21961341
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000354272A Expired CA1162987A (en) | 1979-06-18 | 1980-06-18 | Method and means for detecting magnetic deposits in heat exchanger and the like |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS566178A (en) |
| BE (1) | BE883851A (en) |
| CA (1) | CA1162987A (en) |
| DE (1) | DE3022060A1 (en) |
| FR (1) | FR2459490A1 (en) |
| GB (1) | GB2055473B (en) |
| SE (1) | SE8004469L (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2159954A (en) * | 1984-06-06 | 1985-12-11 | British Gas Corp | Apparatus, system and method for detecting a discontinuity in a pipe or conduit |
| FR2928024B1 (en) * | 2008-02-22 | 2010-12-10 | Areva Np | DEVICE AND METHOD FOR DETECTING AND MEASURING THE WATER PASSAGE CLOSURE RATE IN A SECONDARY CIRCUIT OF A PRESSURIZED WATER NUCLEAR REACTOR |
| FR2927723B1 (en) * | 2008-02-18 | 2010-12-10 | Areva Np | DEVICE AND METHOD FOR DETECTING AND MEASURING THE WATER PASSAGE CLOSURE RATE IN A SECONDARY CIRCUIT OF A PRESSURIZED WATER NUCLEAR REACTOR |
| FR2931241B1 (en) * | 2008-05-16 | 2010-05-28 | Electricite De France | METHOD AND DEVICE FOR DETECTING DEPOSITS COMPRISING AT LEAST ONE FERROMAGNETIC MATERIAL ON OR NEAR THE OUTER WALL OF A TUBE |
| FR2950433B1 (en) | 2009-09-24 | 2014-12-19 | Electricite De France | IMPROVEMENTS IN A METHOD AND DEVICE FOR DETECTING DEPOSITS COMPRISING AT LEAST ONE FERROMAGNETIC MATERIAL ON OR NEAR THE OUTER WALL OF A TUBE |
| FR2950434B1 (en) | 2009-09-24 | 2011-11-25 | Electricite De France | IMPROVEMENTS IN DETECTION OF DEPOSITS COMPRISING AT LEAST ONE FERROMAGNETIC MATERIAL ON OR NEAR THE OUTER WALL OF A TUBE |
| FR2950432B1 (en) | 2009-09-24 | 2015-06-05 | Electricite De France | METHODS AND DEVICES FOR DETECTING DEPOSITS IN INTERSTICES OF A CONNECTION BETWEEN A TUBE AND A PLATE |
| FR2960336B1 (en) | 2010-05-19 | 2012-06-22 | Areva Np | ASSEMBLY AND METHOD FOR DETECTING AND MEASURING THE WATER PASSAGE CLOSURE RATE IN A SECONDARY CIRCUIT OF A PRESSURIZED WATER NUCLEAR REACTOR |
| JP5791279B2 (en) * | 2011-01-06 | 2015-10-07 | 三菱重工業株式会社 | Deposit measuring apparatus, deposit measuring method, and deposit measuring program |
| FR3015757B1 (en) * | 2013-12-23 | 2019-05-31 | Electricite De France | METHOD FOR QUANTITATIVE ESTIMATING OF THE PLATE COATING OF A STEAM GENERATOR |
| FR3028042B1 (en) | 2014-11-05 | 2016-12-16 | Electricite De France | DEVICE AND METHOD FOR DETECTING DEPOSITS OF AT LEAST ONE FERROMAGNETIC MATERIAL ON THE OUTER WALL OF A TUBE |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU439594B2 (en) * | 1970-01-12 | 1973-08-20 | Joseph Lucas (Industries) Limited | Magnetic probe |
| US3906358A (en) * | 1973-11-12 | 1975-09-16 | Combustion Eng | Probe train including a flaw detector and a radiation responsive recording means with alignment means having a natural curved cast |
| JPS5094987A (en) * | 1973-12-22 | 1975-07-29 | ||
| US4088946A (en) * | 1975-07-28 | 1978-05-09 | Westinghouse Electric Corp. | Magnetic bridge transducer formed with permanent magnets and a hall effect sensor for identifying the presence and location of ferromagnetic discontinuities within or on a tubular specimen |
| US4194149A (en) * | 1977-12-15 | 1980-03-18 | The Babcock & Wilcox Company | Method for generating the eddy current signature of a flaw in a tube proximate a contiguous member which obscures the flaw signal |
-
1980
- 1980-06-12 DE DE19803022060 patent/DE3022060A1/en not_active Withdrawn
- 1980-06-17 BE BE0/201052A patent/BE883851A/en not_active IP Right Cessation
- 1980-06-17 JP JP8206880A patent/JPS566178A/en active Pending
- 1980-06-17 SE SE8004469A patent/SE8004469L/en not_active Application Discontinuation
- 1980-06-17 GB GB8019687A patent/GB2055473B/en not_active Expired
- 1980-06-17 FR FR8013400A patent/FR2459490A1/en not_active Withdrawn
- 1980-06-18 CA CA000354272A patent/CA1162987A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| SE8004469L (en) | 1980-12-19 |
| JPS566178A (en) | 1981-01-22 |
| GB2055473B (en) | 1984-01-25 |
| BE883851A (en) | 1980-10-16 |
| FR2459490A1 (en) | 1981-01-09 |
| GB2055473A (en) | 1981-03-04 |
| DE3022060A1 (en) | 1981-01-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |