USRE28425E - Oil filled electric submarine cable with oil duct restrictors - Google Patents
Oil filled electric submarine cable with oil duct restrictors Download PDFInfo
- Publication number
- USRE28425E USRE28425E US48395674A USRE28425E US RE28425 E USRE28425 E US RE28425E US 48395674 A US48395674 A US 48395674A US RE28425 E USRE28425 E US RE28425E
- Authority
- US
- United States
- Prior art keywords
- duct
- oil
- restrictors
- cable
- flow
- 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
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 21
- 239000012530 fluid Substances 0.000 abstract description 13
- 230000009467 reduction Effects 0.000 description 5
- 239000004020 conductor Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 241001602730 Monza Species 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B9/00—Power cables
- H01B9/06—Gas-pressure cables; Oil-pressure cables; Cables for use in conduits under fluid pressure
- H01B9/0616—Oil-pressure cables with enclosed conduits
Definitions
- the restrictor can have the shape of the restrictor designated by the reference numeral 10 in the figure, namely, it can be formed by a tubular element 11 also having a diameter substantially equal to the diameter of the duct 2 and provided with an inner transverse wall or diaphragm 12 having one or more holes 13 extending axially of the duct 2.
- the operation and the sizing and spacing criteria of this alternative embodiment are substantially the same as those indicated hereinbetore for the first embodiment.
Abstract
1. IN AN ELECTRIC CABLE HAVING A DUCT FOR THE FLOW OF AN INSULATING FLUID, THE COMBINATION THEREWITH OF A PLURALITY OF RESTRICTORS IN SAID DUCT, SAID RESTRICTORS BEING (DISPOSED IN) SPACED (RELATION) WITH RESPECT TO EACH OTHER LONGITUDINALLY OF SAID DUCT BY A DISTANCE OF AT LEAST ABOUT 200 METERS AND EACH OF SAID RESTRICTORS COMPRISES A WALL EXTENDING ACROSS SAID DUCT AND PREVENTING THE FLOW OF FLUID ALONG SAID DUCT BUT HAVING A HOLE THERETHROUGH OF A SIZE WHICH PERMITS THE FLOW OF SAID INSULATING FLUID THERETHROUGH BUT PREVENTS THE FLOW OF WATER DROPS THERETHROUGH.
Description
May 29, 19% P. G. PRIARQGGIA ET AL Re. 28,425
OIL FILLED ELECTRIC SUBMARINE CABLE WITH UIL DUCT RESTRIC'IORS Qriginal Files? June 18, 1973 ////////////////////////////4//////////////////////// NKMQQQDRQQQLQ Re. 28,425 Reissued May 20, 1975 United States Patent 28,425 ELECTRIC SUBMARINE CABLE WITH OIL DUCT RESTRICTORS Paolo Gazzana Priaroggia, Milan, and Antonio Ferrentino, Monza, Italy, by Industrie Pirelli Societa per Azioni, Milan, Italy, assignee Original No. 3,798,345, dated Mar. 19, 1974, Ser. No. 371,123, June 18, 1973. Application for reissue June 28, 1974, Ser. No. 483,956 Claims'priority, application Italy, July 3, 1972,
. 1 Int. Cl. Holb 9/06 U.S. Cl. 174-15 C 7 Claims Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue on. FILLED ABSTRACT OF THE DISCLOSURE The present invention relates to electric submarine cables of the oil-filled type, and in particular, it relates to an auxiliary device intended tolimit the damage caused byrninor water infiltration into the oil ducts present in such' cables. The auxiliary device of the invention can serve for electric cables laid on the bottom of any water course-or water crossing (river, lake, etc.) and not only on the sea bottom.
It is .likely that oil-filled submarine cables will suffer.
damage duringuse not the fault of those who design,- manufacture, and/or install the cables. Said damage, in the form of a tear, is often due to strong impacts, with the cables, of blunt or sharp bodies, such, as, for example, ships anchors.
The cable continues to operate satisfactorily if the tear extends only to the outer covering or to the protecting sheath: However, if the tear is such that the insulating paper and the conductors are also cut, and if, at the extreme, the cable is ruptured, the fluid oil which is constantly fed to the cable from the appropriate tanks and which circulates in the ducts present in the cable inside, flows out of the cable through the tear.
' 'If the diameter of the oil duct in the cable is relatively large, said outflow can cause serious economical damage because of the amount of wasted oil, and moreover, it canpollute the water where the cable is laid, since a long time can pass before the cable is repaired.
On the other hand, a reduction of the diameter of the ducts can limit the oil loss, but results in other disadvanages. More specifically, since in the transitory heating or cooling periods of the cable there are oil movements along the cable because of thermal expansion and contraction, it is necessary to take intoaccount, in designing the cable, the greater losses of pressure which result from a reduced diameter. Therefore, to obtain a sufficient minimum pressure at any point of the cable, higher pressures are to be anticipated in other cable parts, the difference between said pressures being a function of the losses of pressure. Therefore, a smaller diameter of the oil duct compels the adoption of a stronger, and consequently more expensive, structure.
For these reasons, the designer has to face two problems which require opposite, or conflicting, solutions. In
other words, ducts of larger diameter would be more convenlent for reducing losses of pressure, but, on the other hand, this solution would cause significant oil waste in the event of damage.
It has been proposed to limit the oil outflow by means of flow rate reduction valves, having the purpose of supplying the cable at its ends with amounts of oil less than a pie-established amount even in the event of a complete cuttlng of the cable itself. These expedients are actually able to reduce the oil amount which is wasted, but, owing to the different physical characteristics of water and oil, and in particular, their surface tensions, it may happen that in the damaged zone one or more water drops penetrate into the oil duct, as a consequence of the low flow rate of the outflowing oil. After penetrating, said water drops can migrate along the cable towards the portion of the cable which is at the lowest level, increasing, therefore, the extent of the damage, since a long portion of the cable must be replaced to be sure that no water drops exist in the repaired cable length.
The present invention has, as one object, the provision of a device for oil-filled cables, which is able to stop the migration of the water drops along the cable, so that large d ameters of the oil duct can be used and the reduction of oil flow rate can be obtained without the disadvantages mentioned hereinbefore.
Accordingly, one object of the present invention is to provide an oil-filled, electric, submarine cable provided with one or more oil ducts, characterized in that each of said ducts contains a plurality of restricting devices, or restrictors, which may be in the form of diaphragms, and which are spaced apart along the cable and each provided with'at least one opening of such dimension as to avoid the passage of water drops from one side to the other thereof.
\ Preferably, said opening is circular and has a diameter no greater than the diameter assumed by the water drops, in consequence of their surface tension, under actual operating conditions.
. In a preferred embodiment of the invention, said restrictors are cylindrical blocks situated inside the oil duct and provided with a through hole disposed along the axis of the duct.
Alternatively, the restrictor can also be a tubular element inserted in the duct and provided with a hole in an inner transverse Wall or diaphragm.
The size of the hole in each restrictor depends on many variable factors, among which are the vsurface tensions and the viscosities of water and of the oil used.
However, said size for any given set of conditions can be easily determined by the designer skilled in the art, even, if necessary, in an experimental manner, once the characteristics of the materials employed in the cable and its operating conditions have been established.
The invention and its objects and advantages will be apparent from the following detailed description of presently preferred embodiments thereof, which description should be considered in conjunction with the accompanying drawing, the single figure of which illustrates a longitudinal section of a single core, oil-filled cable having a plurality of restrictors of the invention in the oil duct thereof. Although the drawing illustrates two different embodiments of the restrictors, the restrictors in a cable may be of the same type.
In the figure, the hollow conductor 1 defines an oil duct 2. Around the conductor 1 there is insulation 3 formed by paper layers which are impregnated with oil. Outside said insulation 3, there are a metal sheath 4, a sheath 4' of elastomeric or plastomeric material, and a set of protective layers 5 of a known type (frettage, armor, etc).
Inside the duct 2 is visable a first restrictor 6 formed by a block 7 of metallic material (for example, of the same material as the conductor 1) having a diameter substantially the same as that of the duct 2. The block 7 has a hole 8 extending along the axis of the duct 2 and of a diameter which does not allow the passage of water drops, such as the water drop 9.
The water drop 9, which may, for example, have penetrated the cable through a rupture thereof, and which reaches the restrictor 6, cannot pass through the hole 8 because its surface tension would maintain it in a round form, thereby preventing it from entering the hole 8. This is true whether or not oil movement takes place. However, the movement of the oil through the hole 8 takes place in the direction from the end of the cable towards the damaged zone to flow out of the latter, and therefore, the oil movement is such as to oppose to the advancement of the drop through said hole 8.
As stated hereinbefore, the determination of the size of the hole 8 is within the knowledge of the technician skilled in this field after having established the characteristics of the cable. However, by way of example only, if the cable has an oil duct diameter of about 30 mm., is intended to operate at a pressure of about 15 kg. /cm.*, and is provided with a flow rate reduction valve to provide, in the event of failure, an oil flow from 100 liters/ min. to a few liters/min., the restrictors 6 can be disposed at regular intervals variable from about 200 meters to 2,000 meters from each other, and can be formed by blocks 7 having a length of from to 100 millimeters and a central hole 8v with a diameter variable mm 4 to 12 millimeters.
Alternatively, the restrictor can have the shape of the restrictor designated by the reference numeral 10 in the figure, namely, it can be formed by a tubular element 11 also having a diameter substantially equal to the diameter of the duct 2 and provided with an inner transverse wall or diaphragm 12 having one or more holes 13 extending axially of the duct 2. The operation and the sizing and spacing criteria of this alternative embodiment are substantially the same as those indicated hereinbetore for the first embodiment.
By the adoption of restrictors 6 or 10 according to the present invention, it has been found to be possible to increase considerably the size of the oil duct 2, resulting, however, in only a small oil loss in the event of failure, and setting the reduction valves to a relatively low flow rate. In fact, possible water infiltration caused by said low flow rate is prevented by the restrictors nearest to the damaged zone, thereby enabling the repair of only a reduced length of cable. On the other hand, the adoption of a duct 2 of larger diameter reduces the losses of pressure and consequently, for the reasons explained hereinbefore, the cable can be designed for lower stresses in the transitory periods since the presence of the restrictors does not atfect substantially the total pressure losses, because the restrictors, e.g. 6 and/or 10, are spaced apart along the cable and produce only localized losses of pressure. 7
It will be apparent to those skilled in the art that various modifications may be made without departing from the principles of the invention exemplified by the preferred embodiments of the invention which have been illustrated and described.
What is claimed is:
1. In an electric cable having a duct for the flow of an insulating fluid, the combination therewith of a plurality of restrictors in said duct, said restrictors being [disposed in] spaced [relation] with respect to each other longitudinally of said duct by a distance of at least about 200 meters and each of said restrictors comprises a wall extending across said duct and preventing the flow of fluid along said duct but having a hole therethrough of a size which permits the flow of said insulating fluid therethrough but prevents the flow of water drops therethrough.
2. An electric cable as set forth in claim 1, wherein said insulating fluid is an oil and wherein said hole is of a size smaller than the size of said water drops assumed thereby under the operating conditions of said cable and because of the surface tension of the dater drops.
3. An electric cable as set forth in claim 2, wherein said duct is circular in cross-section and wherein each of said restrictors is a cylindrical block frictionally engaging the inner wall of said duct and said hole extends axially of said duct.
4. An electric cable as set forth in claim 2, wherein said duct is tubular and wherein each of said restrictors com.- prises a tubular element having said wall intermediate the ends thereof, the exterior size of said element being substantially equal to the size of the interior wall of said duct to cause the tubular element to frictionally engage said duct.
5. An electric cable as set forth in claim 2, wherein said restrictors are spaced from each other by a distance from about 200 to 2,000 meters and the size of said hole is about 4 millimeters to 12 millimeters in diameter.
6. In an electric cable system comprising an electric cable having a duct for the flow of an insulating fluid and valve means for reducing the flow rate of said fluid in said duct after the occurrence of a break in said cable, the combination therewith of means for preventing the flow of water drops into said duct without a substantial increase in the total fluid pressure losses in said duct comprising a plurality of restrictors in said duct, said restrictors being disposed in spaced relation with respect to each other longitudinally of said duct and each of said restrictors comprises a wall extending across said duct and preventing the flow of fluid along said duct but having a hole therethrough of a size which permits the flow of said insulating fluid therethrough but prevents the flow of water drops therethrough. I
7. An electric cable system as set forth in claim 6, wherein said restrictors are spaced from each other by a distance of at least about 200 meters.
References Cited The following references, cited by the Examiner, are of record in the patented file of this patent or the original ARTHUR T. GRIMLEY, Primary Examiner us. c1. X.R. 138-44; 174-15 0, 2s 1:;210-315
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT26535/72A IT962363B (en) | 1972-07-03 | 1972-07-03 | IMPROVEMENTS ON SUBMARINE ELECTRIC CABLES OF THE FLUID OIL TYPE |
Publications (1)
Publication Number | Publication Date |
---|---|
USRE28425E true USRE28425E (en) | 1975-05-20 |
Family
ID=11219726
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00371123A Expired - Lifetime US3798345A (en) | 1972-07-03 | 1973-06-18 | Oil filled electric submarine cable with oil duct restrictors |
US48395674 Expired USRE28425E (en) | 1972-07-03 | 1974-06-28 | Oil filled electric submarine cable with oil duct restrictors |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00371123A Expired - Lifetime US3798345A (en) | 1972-07-03 | 1973-06-18 | Oil filled electric submarine cable with oil duct restrictors |
Country Status (12)
Country | Link |
---|---|
US (2) | US3798345A (en) |
JP (1) | JPS5734605B2 (en) |
AR (1) | AR194902A1 (en) |
AU (1) | AU474645B2 (en) |
CA (1) | CA968039A (en) |
DK (1) | DK142860B (en) |
FR (1) | FR2237284B1 (en) |
GB (1) | GB1389622A (en) |
IT (1) | IT962363B (en) |
NO (1) | NO134475C (en) |
SE (1) | SE380659B (en) |
ZA (1) | ZA734393B (en) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NO135387C (en) * | 1973-05-22 | 1977-03-30 | Standard Tel Kabelfab As | POWER POWER CABLE AND PROCEDURE TO MANUFACTURE THIS. |
IT1161893B (en) * | 1983-02-14 | 1987-03-18 | Pirelli Cavi Spa | MULTI-POLE CABLE WITH FLUID OIL |
IT1163548B (en) * | 1983-06-21 | 1987-04-08 | Pirelli Cavi Spa | MULTI-POLE CABLE WITH FLUID OIL |
US4775962A (en) * | 1987-03-27 | 1988-10-04 | Mobil Oil Corporation | Marine seismic streamer employing variable aperture flow through spacers |
US5207243A (en) * | 1992-07-06 | 1993-05-04 | Sarro Claude A | Two-way piston check valve |
GB9319025D0 (en) * | 1993-09-14 | 1993-10-27 | Ans Karsto Metering & Technolo | Flow cobditioner |
US5495872A (en) * | 1994-01-31 | 1996-03-05 | Integrity Measurement Partners | Flow conditioner for more accurate measurement of fluid flow |
US5581883A (en) * | 1995-02-27 | 1996-12-10 | Whirlpool Corporation | Method of assembling an expansion device for a refrigeration system |
US7011180B2 (en) * | 2002-09-18 | 2006-03-14 | Savant Measurement Corporation | System for filtering ultrasonic noise within a fluid flow system |
US7845688B2 (en) * | 2007-04-04 | 2010-12-07 | Savant Measurement Corporation | Multiple material piping component |
CN105575495B (en) * | 2015-08-27 | 2018-01-30 | 盐城市国一电缆材料厂 | Improve oil-filled cable |
JP6341240B2 (en) * | 2016-08-05 | 2018-06-13 | 住友電気工業株式会社 | Pipe type oil immersion insulated cable, repair oil immersion insulated cable, temporary oil stopper, and pipe type oil immersion insulated cable repair method |
EP3584807A4 (en) * | 2017-02-16 | 2020-11-25 | LS Cable & System Ltd. | Power cable |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2288532A (en) * | 1939-09-12 | 1942-06-30 | Budd L Knapp | Filter device |
US2788125A (en) * | 1953-07-31 | 1957-04-09 | Edmond F Webb | Fuel filter |
US2872043A (en) * | 1956-06-06 | 1959-02-03 | Fram Corp | Water separators |
US3016345A (en) * | 1958-05-14 | 1962-01-09 | Permanent Filter Corp | Hydrocarbon filtration |
US3085690A (en) * | 1959-03-02 | 1963-04-16 | Briggs Filtration Company | Water separator |
US3627677A (en) * | 1969-10-14 | 1971-12-14 | Minnesota Mining & Mfg | Process of removing oil from mixtures of oil and aqueous media |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE843265C (en) * | 1950-11-10 | 1952-07-07 | Felten & Guilleaume Carlswerk | Oil cable for laying under water |
-
1972
- 1972-07-03 IT IT26535/72A patent/IT962363B/en active
-
1973
- 1973-05-23 JP JP5693673A patent/JPS5734605B2/ja not_active Expired
- 1973-06-18 US US00371123A patent/US3798345A/en not_active Expired - Lifetime
- 1973-06-18 AR AR248631A patent/AR194902A1/en active
- 1973-06-25 GB GB3013573A patent/GB1389622A/en not_active Expired
- 1973-06-27 ZA ZA734393A patent/ZA734393B/en unknown
- 1973-06-28 AU AU57455/73A patent/AU474645B2/en not_active Expired
- 1973-06-29 CA CA175,283A patent/CA968039A/en not_active Expired
- 1973-07-02 NO NO2711/73A patent/NO134475C/no unknown
- 1973-07-02 DK DK365373AA patent/DK142860B/en not_active IP Right Cessation
- 1973-07-02 FR FR7324170A patent/FR2237284B1/fr not_active Expired
- 1973-07-02 SE SE7309308A patent/SE380659B/en unknown
-
1974
- 1974-06-28 US US48395674 patent/USRE28425E/en not_active Expired
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2288532A (en) * | 1939-09-12 | 1942-06-30 | Budd L Knapp | Filter device |
US2788125A (en) * | 1953-07-31 | 1957-04-09 | Edmond F Webb | Fuel filter |
US2872043A (en) * | 1956-06-06 | 1959-02-03 | Fram Corp | Water separators |
US3016345A (en) * | 1958-05-14 | 1962-01-09 | Permanent Filter Corp | Hydrocarbon filtration |
US3085690A (en) * | 1959-03-02 | 1963-04-16 | Briggs Filtration Company | Water separator |
US3627677A (en) * | 1969-10-14 | 1971-12-14 | Minnesota Mining & Mfg | Process of removing oil from mixtures of oil and aqueous media |
Also Published As
Publication number | Publication date |
---|---|
ZA734393B (en) | 1974-06-26 |
AU5745573A (en) | 1975-01-09 |
JPS4951580A (en) | 1974-05-18 |
DK142860C (en) | 1981-09-07 |
FR2237284A1 (en) | 1975-02-07 |
IT962363B (en) | 1973-12-20 |
NO134475B (en) | 1976-07-05 |
AR194902A1 (en) | 1973-08-24 |
NO134475C (en) | 1976-10-13 |
GB1389622A (en) | 1975-04-03 |
CA968039A (en) | 1975-05-20 |
DK142860B (en) | 1981-02-09 |
JPS5734605B2 (en) | 1982-07-23 |
SE380659B (en) | 1975-11-10 |
FR2237284B1 (en) | 1978-10-20 |
US3798345A (en) | 1974-03-19 |
AU474645B2 (en) | 1976-07-29 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SOCIETA PIRELLI S.P.A., PIAZZALE CADORNA 5, 20123 Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:INDUSTRIE PIRELLI S.P.A.;REEL/FRAME:003847/0084 Effective date: 19810101 |