US4145915A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Early crack detection
Assignee: ConocoPhillips Co
•
Filing: 1978-03-20
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Granted: 1979-03-27
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Expires: 1998-03-20
Abstract
Abstract Early detection of cracks in non-permeable, structural members subject to stress is effected before the cracks traverse the member by: (a) forming a cavity in the structural member or adjacent thereto such that a crack forming in the structural member provides a passage for a fluid to flow between the environment and the cavity without passing through the entire structural member, (b) sealing a fluid passageway in fluid communication from the cavity to a source of pressure different than ambient pressure at the structural member and to a pressure sensor, (c) imparting a higher or lower pressure to the cavity and the fluid passageway, and, (d) monitoring the internal pressure in the cavity and fluid passageway with the pressure sensor, Such that a crack in the structural member penetrating to the cavity allows passage of fluid between the environment and the cavity and is thus detected by the pressure sensor. The apparatus and process is particularly applicable to early detection with vacuum of cracks in the heat affected zone adjacent to welds on critical stressed members of an offshore platform. A strain guage system may be employed in conjunction with the crack detection system.
Inventors
- 👤 Donald H. Oertle
- 👤 Marvin L. Peterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:11
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/26; G01M3/28; G01M3/2884; G01N; G01N19/00; G01N19/08
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
158 words
A process for the early detecting of the formation of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the process comprising: (a) forming a cavity in the structural member or adjacent thereto such that a crack forming in the structural member provides a passage for a fluid to flow between the environment and the cavity without traversing the structural member, (b) sealing a fluid passageway in fluid communication from the cavity to a source of pressure different than ambient at the structural member and to a pressure sensor, (c) imparting a higher or lower pressure than ambient to the cavity and the fluid passageway, and, (d) monitoring the internal pressure in the cavity and fluid passageway with the pressure sensor, such that a crack in the structural member penetrating to the cavity allows passage of fluid between the environment and the cavity and is thus detected by the pressure sensor.
Claim 2
Dependent Claim
158 words
A process for the early detecting of the formation of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the process comprising: (a) forming a cavity in the structural member or adjacent thereto such that a crack forming in the structural member provides a passage for a fluid to flow between the environment and the cavity without traversing the structural member, (b) sealing a fluid passageway in fluid communication from the cavity to a source of pressure different than ambient at the structural member and to a pressure sensor, (c) imparting a higher or lower pressure than ambient to the cavity and the fluid passageway, and, (d) monitoring the internal pressure in the cavity and fluid passageway with the pressure sensor, such that a crack in the structural member penetrating to the cavity allows passage of fluid between the environment and the cavity and is thus detected by the pressure sensor.
Claim 3
Dependent Claim
36 words
The process of claim 1 wherein the cavity is milled into the heat affected zone adjacent to a weld joint on the structural member and the pressure imparted to the cavity in (c) is a vacuum.
Claim 4
Dependent Claim
17 words
The process of claim 2 wherein a plurality of cavities are formed in the heat affected zone.
Claim 5
Dependent Claim
38 words
The process of claim 2 wherein the structural member is a part of an offshore platform and wherein the heat affected zone is adjacent to a weld joint joining the member to another member of the offshore platform.
Claim 6
Dependent Claim
87 words
The process of claim 4 wherein the passageway is a metal tube, wherein the cavity is a drill bore having a volume less than 1% of the heat affected zone, wherein the drill bore traverses a substantial portion of the heat affected zone and has a length at least 10 times its diameter, wherein the sealant is an epoxy resin based sealant, wherein the heat affected zone sensed is below the surface of the water, and wherein the pressure sensor is above the surface of the water.
Claim 7
Dependent Claim
18 words
The process of claim 5 wherein the sensor triggers an alarm upon loss of vacuum in the system.
Claim 8
Dependent Claim
26 words
The process of claim 5 wherein a plurality of cavities are formed in a heat affected zone near a weld joint on a critical stressed member.
Claim 9
Dependent Claim
48 words
The process of claim 7 wherein a plurality of structural members are monitored with a common vacuum passageway and vacuum source, wherein loss of vacuum in a line going to any cavity results in triggering of an alarm and shutting off that line from the common vacuum passageway.
Claim 10
Dependent Claim
35 words
The process of claim 1 wherein the fluid passageway comprises a tubular member and the cavity is formed adjacent to the structural member by adhering the tubular member to the structural member with a sealant.
Claim 11
Dependent Claim
77 words
The process of claim 1 wherein the fluid passageway comprises a tubular member, wherein the cavity is formed adjacent to the structural member by forming a patch by placing the tubular member adjacent to the structural member in fluid communication with a permeable material also placed adjacent to the structural member and sealing both from the environment with an impermeable sealant, and wherein the pressure imparted to the cavity in (c) is below ambient or a vacuum.
Claim 12
Dependent Claim
35 words
The process of claim 10 wherein the tubular member is overlain by the permeable material, the permeable material is overlain by an impermeable barrier, and both are sealed from the environment by the impermeable sealant.
Claim 13
Dependent Claim
35 words
The process of claim 10 wherein the tubular member is underlain by the permeable material, the tubular member is overlain by an impermeable barrier, and both are sealed from the environment by the impermeable sealant.
Claim 14
Dependent Claim
54 words
The process of claim 10 wherein the structural member is a part of an offshore platform and is secured to other structural members by weld joints, wherein the patch is placed across a portion of the heat affected zone adjacent to a weld joint joining the member to another member of an offshore platform.
Claim 15
Dependent Claim
52 words
The process of claim 13 wherein the patch covers no more than 50% of the heat affected zone, wherein the sealant is an epoxy resin based sealant, wherein the heat affected zone sensed is below the surface of the water, and wherein the pressure sensor is above the surface of the water.
Claim 16
Dependent Claim
19 words
The process of claim 14 wherein the pressure sensor triggers an alarm upon loss of vacuum in the system.
Claim 17
Dependent Claim
26 words
The process of claim 15 wherein a plurality of patches are placed across a heat affected zone near a weld joint on a critical stressed member.
Claim 18
Dependent Claim
41 words
The process of claim 16 wherein a plurality of structural members are monitored with a common vacuum passageway, wherein an alarm is triggered by the sensor upon a pre-determined loss of vacuum, and wherein the line having leakage is shut off.
Claim 19
Dependent Claim
35 words
The process of claim 17 wherein the tubular member in the patch is underlain by the permeable material, and overlain by an impermeable barrier, and both are sealed from the environment by the impermeable sealant.
Claim 20
Dependent Claim
37 words
The process of claim 10 wherein strain on the structural member is monitored by adhering a strain guage sensor to the structural member within the patch and passing an insulated electrical conductor therefrom to a read-out therefore.
Claim 21
Dependent Claim
111 words
The process of claim 19 wherein the structural member is a part of an offshore platform, wherein the patch is placed across the heat affected zone adjacent to a weld joint on the structural member, wherein the heat affected zone is adjacent to a weld joint joining the member to another member of the offshore platform, wherein the passageway is a metal tube, wherein the heat affected zone sensed is below the surface of the water, wherein the vacuum sensor is above the surface of the water, and wherein the insulated electrical conductor is passed through the metal tube for at least the distance to above the surface of the water.
Claim 22
Independent Claim
64 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a cavity formed from the surface into the structural member, (b) a fluid passageway sealed to and passing from the cavity to a source of pressure different than ambient and to a sensor providing fluid-tight communication therebetween.
Claim 23
Independent Claim
64 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a cavity formed from the surface into the structural member, (b) a fluid passageway sealed to and passing from the cavity to a source of pressure different than ambient and to a sensor providing fluid-tight communication therebetween.
Claim 24
Dependent Claim
35 words
The apparatus of claim 21 wherein a strain guage sensor is adhered to the structural member within the cavity and wherein an insulated conductor passes from the strain guage sensor to a read-out device therefore.
Claim 25
Dependent Claim
163 words
The apparatus of claim 22 wherein the cavity is milled into the heat affected zone adjacent to a weld joint on the structural member, wherein the source of pressure in (b) is a vacuum source, wherein the structural member is a part of an offshore platform, wherein the heat affected zone is adjacent to a weld joint joining the member to another member of the offshore platform, wherein the passageway is a metal tube, wherein the cavity is a drill bore having a volume less than 1% of the heat affected zone, wherein the drill bore traverses a substantial portion of the heat affected zone, wherein the sealant is an epoxy resin based sealant, wherein the heat affected zone sensed is below the surface of the water, wherein the pressure sensor is above the surface of the water, wherein the conductor from the strain guage to the read-out is passed through the vacuum passageway to at least above the surface of the water.
Claim 26
Dependent Claim
53 words
The apparatus of claim 23 wherein the sensor is rigged to trigger an alarm upon loss of vacuum in the system, wherein a plurality of structural members are monitored with a common vacuum passageway, and wherein an alarm is rigged to be triggered by the pressure sensor upon a pre-determined loss of vacuum.
Claim 27
Independent Claim
95 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a fluid-tight passageway in sealed vacuum communication between a source, of pressure different than ambient, a pressure sensor, and the surface of the structural member, (b) a permeable material adjacent to the structural member and the fluidtight passageway and in fluid communication therethrough to both, (c) an impermeable sealant covering the end of the passageway and the permeable material providing a fluidtight seal between them and the environment.
Claim 28
Independent Claim
95 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a fluid-tight passageway in sealed vacuum communication between a source, of pressure different than ambient, a pressure sensor, and the surface of the structural member, (b) a permeable material adjacent to the structural member and the fluidtight passageway and in fluid communication therethrough to both, (c) an impermeable sealant covering the end of the passageway and the permeable material providing a fluidtight seal between them and the environment.
Claim 29
Dependent Claim
45 words
The apparatus of claim 25 wherein the fluid-tight passageway is a vacuum passageway, one end of the vacuum passageway is overlain by the permeable material, the permeable material is overlain by an impermeable barrier, and both are sealed from the environment by the impermeable sealant.
Claim 30
Dependent Claim
23 words
The apparatus of claim 26 wherein the sealant covers no more than 10% of the surface of the structural member to be sensed.
Claim 31
Independent Claim
87 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a source of pressure different than ambient, (b) a pressure sensor, (c) a fluid-tight line connecting the non-ambient pressure source and the pressure sensor, (d) a patch sealed in fluid-tight relationship to the line, the patch comprising a permeable material adjacent to the end of the line and to the structural member and sealed thereto with a fluid impermeable sealant.
Claim 32
Independent Claim
87 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a source of pressure different than ambient, (b) a pressure sensor, (c) a fluid-tight line connecting the non-ambient pressure source and the pressure sensor, (d) a patch sealed in fluid-tight relationship to the line, the patch comprising a permeable material adjacent to the end of the line and to the structural member and sealed thereto with a fluid impermeable sealant.
Claim 33
Dependent Claim
52 words
The apparatus of claim 28 wherein the patch is placed across the heat-affected zone adjacent to a weld joint on the structural member, wherein the source of pressure other than ambient is a vacuum source, wherein the pressure sensor is a vacuum sensor, and wherein the fluid-tight line is a vacuum-tight line.
Claim 34
Dependent Claim
17 words
The apparatus of claim 29 wherein a plurality of patches are placed across the heat affected zone.
Claim 35
Dependent Claim
38 words
The apparatus of claim 29 wherein the structural member is a part of an offshore platform and wherein the heat affected zone is adjacent to a weld joint joining the member to another member of the offshore platform.
Claim 36
Dependent Claim
50 words
The apparatus of claim 29 wherein the patch is elongated and is placed to cover in a zig-zag or serpentine fashion a substantial portion of the heat affected zone adjacent to a weld joint joining an underwater member of an offshore platform to another underwater member of an offshore platform.
Claim 37
Dependent Claim
21 words
The apparatus of claim 29 wherein the sensor is rigged to trigger an alarm upon loss of vacuum in the system.
Claim 38
Dependent Claim
32 words
The apparatus of claim 33 wherein a plurality of patches are monitored with a common vacuum passageway and wherein an alarm is triggered by the sensor upon a pre-determined loss of vacuum.
Claim 39
Dependent Claim
18 words
The apparatus of claim 34 wherein substantially all critical stressed weld joints on an offshore platform are monitored.
Claim 40
Dependent Claim
77 words
the apparatus of claim 35 wherein the patches comprise a first layer of porous paper; overlying the paper, the end of the vacuum line; overlying the end of the vacuum line, a layer of metallic foil covering the end of the vacuum line and the porous paper; overlying the foregoing, an overlying layer of epoxy-based sealant forming a fluid-tight barrier adhering the paper, the end of the vacuum line, and the foil barrier to the structural member.
Claim 41
Dependent Claim
27 words
The apparatus of claim 28 wherein the patches have an opening opposite the end of the line such that the system can be flushed with a fluid.
Claim 42
Dependent Claim
17 words
The apparatus of claim 37 wherein the patch has a length at least 2 times its width.
Claim 43
Dependent Claim
139 words
The apparatus of claim 29 wherein a plurality of patches are placed across the heat affected zone adjacent to a weld joint on the structural member, wherein the structural member is part of an offshore platform and wherein the heat affected zone is adjacent to a weld joint joining the member to another member of the offshore platform, wherein the weld joint is under the surface of the water, wherein a common vacuum source, and passageway is employed to pull vacuum on the plurality of patches, wherein a differential pressure sensor is emplaced in fluid-tight relationship in the vacuum line going to each patch, and wherein the differential pressure sensing device in each vacuum line is rigged to trigger an alarm indicating crack penetration within the structural member to admit environmental fluids into the permeable material of that patch.
Claim 44
Independent Claim
106 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a vacuum source, (b) a vacuum sensor, (c) a vacuum tight line connecting the vacuum source and the vacuum sensor, (d) a patch sealed in vacuum tight relationship to the line, the patch comprising a propping member adjacent to the end of the vacuum line, an impermeable sheet material overlying the propping member so as to form a fluid channel extending therefrom, and the sheet and end of vacuum line sealed from the environment with a fluid impermeable sealant.
Claim 45
Independent Claim
106 words
An apparatus for the early detecting of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the apparatus comprising: (a) a vacuum source, (b) a vacuum sensor, (c) a vacuum tight line connecting the vacuum source and the vacuum sensor, (d) a patch sealed in vacuum tight relationship to the line, the patch comprising a propping member adjacent to the end of the vacuum line, an impermeable sheet material overlying the propping member so as to form a fluid channel extending therefrom, and the sheet and end of vacuum line sealed from the environment with a fluid impermeable sealant.
Claim 46
Dependent Claim
24 words
The apparatus of claim 40 wherein the patch is placed across the heat affected zone adjacent to a weld joint on the structural member.
Claim 47
Dependent Claim
99 words
The apparatus of claim 41 wherein a plurality of patches are placed across the weld joint and heat affected zone, wherein the structural member is a part of an offshore platform, wherein the heat affected zone is adjacent to a weld joint joining the member to another member of the offshore platform and is below the water line, wherein a differential pressure sensor is placed in each vacuum line between the vacuum source and each patch, and wherein each differential pressure sensor is rigged to trigger an alarm upon loss of vacuum under the patch effecting a differential pressure.
Claim 48
Dependent Claim
203 words
A process for the early detecting of the formation of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the process comprising: (a) forming a cavity adjacent to the structural member by forming a patch by placing one end of a tubular member adjacent to the structural member and in fluid communication with a permeable material also placed adjacent to the structural member and sealing both from the environment with an impermeable sealant such that a crack forming in the structural member provides a passage for a fluid to flow between the environment and the cavity without traversing the structural member, (b) sealing the other end of the tubular member in fluid communication to a source of pressure different than ambient at the structural member and to a pressure sensor, (c) imparting pressure other than ambient to the cavity and the interior of the tubular member, and (d) monitoring the internal pressure in the cavity and the interior of the tubular member with the pressure sensor; such that a crack in the structural member penetrating to the cavity allows passage of fluid between the environment and the cavity and is thus detected by the pressure sensor.
Claim 49
Dependent Claim
203 words
A process for the early detecting of the formation of a crack in a non-permeable, structural member subject to stress before the crack traverses the member, the process comprising: (a) forming a cavity adjacent to the structural member by forming a patch by placing one end of a tubular member adjacent to the structural member and in fluid communication with a permeable material also placed adjacent to the structural member and sealing both from the environment with an impermeable sealant such that a crack forming in the structural member provides a passage for a fluid to flow between the environment and the cavity without traversing the structural member, (b) sealing the other end of the tubular member in fluid communication to a source of pressure different than ambient at the structural member and to a pressure sensor, (c) imparting pressure other than ambient to the cavity and the interior of the tubular member, and (d) monitoring the internal pressure in the cavity and the interior of the tubular member with the pressure sensor; such that a crack in the structural member penetrating to the cavity allows passage of fluid between the environment and the cavity and is thus detected by the pressure sensor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-26 | 1982-09-25 | 1983-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-26 | 1986-09-25 | 1987-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-26 | 1990-09-25 | 1991-03-27 | $7700.00 | Window Closed / Lapsed |