Jump to content

User:WJ-Engineer/sandbox

From Wikipedia, the free encyclopedia

Abrasive Water Suspension Jet (AWSJ) cutting[edit]

The Abrasive Water Suspension Jet (AWSJ) - often called “Slurry Jet” or “Water Abrasive Suspension (WAS) jet” - is a specific type of the abrasive water jet, which is used for waterjet cutting. In contrast to the abrasive water injector jet (AWIJ), the abrasive water suspension jet (AWSJ)[1] is characterised by the fact that the mixing of abrasive and water takes place before the nozzle. This has the effect that, in contrast to AWIJ, the jet consists of only two components (water - abrasive).

Since there are only 2 components (water and abrasive) in the AWSJ, the acceleration of the abrasive grains by the water takes place with a significantly increased efficiency compared to the AWIJ[2]. The abrasive grains become faster with the WASS than with the WAIS for the same hydraulic power of the system. Therefore, comparatively deeper or faster cuts can be made with the AWSJ.

AWSJ cutting, in contrast to the AWIJ cutting process described below, can also be used for mobile cutting applications and cutting under water, in addition to machining demanding materials[3][4].[5] Examples include bomb disposal[6] s well as the dismantling of offshore installations[7] or the dismantling of reactor pressure vessel installations in nuclear power plants[8].

Abrasive Water Injector Jet (AWIJ) cutting[edit]

The AWIJ[9] is generated by a water jet that passes through a mixing chamber (a cavity) after exiting the water nozzle and enters a focusing tube at the exit of the mixing chamber. The interaction of the water jet in the mixing chamber with the air inside creates a negative pressure, the water jet entrains air particles. This negative pressure is used for the pneumatic transport of the abrasive into the chamber (the abrasive is led to a lateral opening (bore) of the mixing chamber by means of a hose).

After contact of the abrasive material in the mixing chamber with the water jet, the individual abrasive grains are accelerated and entrained in the direction of the focusing tube. The air used as a carrier medium for transporting the abrasive into the mixing chamber also becomes part of the AWIJ, which now consists of three components (water - abrasive - air). In the focusing tube, which is (should be) optimised in its length for this purpose, the abrasive is further accelerated (energy transfer from the water to the abrasive grain) and the AWIJ ideally leaves the focusing tube at the maximum possible abrasive grain speed.








____________________________ AWSJ article draft_____________________

The Abrasive Water Suspension Jet (AWSJ) - often called “Slurry Jet” or “Water Abrasive Suspension (WAS) jet” - is a specific type of the abrasive water jet, which is used for waterjet cutting. It has to be distinguished from the Abrasive Water Injection Jet (AWIJ).

History[edit]

As early as 1924, a technical system was patented by the inventors Jakob Maurer and Heinrich Friedrich Jakobsen, which was describing a tool for grinding and drilling teeth. According to the patent description, a press water with added abrasive is used (Preßwasser mit Schleifmittelzugabe)[10]. This technology was limited in terms of the pressure level used, but the method of generating the jet already corresponded to the AWSJ principle.

Technological characteristics of abrasive water suspension jet cutting[edit]

In contrast to the abrasive water injector jet (AWIJ), the abrasive water suspension jet (AWSJ)[11] is characterised by the fact that the mixing of abrasive and water takes place before the nozzle. This has the effect that, in contrast to AWIJ, the jet consists of only two components (water - abrasive)[12].

In the development of AWSJ, three different ways of admixing abrasive to water have been investigated and applied so far[13].

One method is to mix the suspension (= water - abrasive mixture) at ambient pressure and pump it directly through a nozzle (in this case, diaphragm pumps are used, for example). Although this method is very easy to use, it has not yet gained economic importance, mainly because of the high abrasive wear in the pump while the suspension is pressurised [Figure below "Direct pumping"].

The second way of generating AWSJ is indirect pressurisation of a premixed suspension [Figure below "Indirect pumping"]. Water is pressurised and drives a piston in a pressure vessel. This forces the premixed suspension out of a high-pressure reservoir and then accelerates the suspension in the nozzle.

The third method of admixing is the so-called bypass principle [figure below "Bypass principle"]. In this case, water is pressurised in the pump. Part of the flow is directed through a bypass line to a high-pressure container that was filled with abrasive in a previous process under ambient pressure (this container is thus filled with a water-abrasive mixture = suspension). The other part of the water quantity, which is in the system from the pump, flows past the pressure vessel in the so-called main stream. The water flowing through the pressure vessel now entrains abrasive particles and thereby reduces the abrasive content in the vessel. This is an important aspect because, due to this property, AWSJ generation used to be a discontinuous process. When the abrasive content in the tank is used up, the AWSJ process must be interrupted. To do this, the system is relieved and brought back to ambient pressure so that the container can be refilled with abrasive.

AWSJ cutting - three different types of water abrasiv suspension jet cutting web
AWSJ cutting - three different types of water abrasiv suspension jet cutting

Recent developments in system technology have offered the following solutions for bypassing a discontinuous cutting process:

Motor cut with a ConSus slurryjet system
Motor cut with a ConSus slurryjet system
  • Two pressure vessels are integrated in the system. Via a so-called switch box, the supply of high-pressure water can be switched between the two tanks in so-called shuttle operation[14]. This means that when the abrasive in one tank is used up, the other tank, which has already been refilled, is available for immediate further use. In this case, the cutting process only has to be interrupted for the short moment of switching over. This is a quasi-continuous process. This system is mainly used in the dismantling of offshore plants, usually as part of a complete system certified for offshore applications.[15][16]
  • The pressure vessel can be filled with abrasive during operation via a patented sluice system (ConSus) and without the need to lower the pressure[8]. By implementing this technology, the AWSJ can be used as a continuous process for the first time, so that the technological and economic advantages can also be used in industrial production[17][18].
Cutting examples cut with abrasive water suspension jet (slurryjet)
Cutting examples cut with abrasive water suspension jet (slurryjet)

Regardless of the technical variants mentioned above, the highly concentrated suspension (high proportion of abrasive) transported out of the container is reunited with the main flow at the so-called mixing piece. From there is transported to the nozzle in a lower concentrated mixture. Within the nozzle (e.g. made of hard metal) the potential energy (pressure) is converted into kinetic energy (speed). In the process, the abrasive grains are also accelerated. Since there are only 2 components (water and abrasive) in the AWSJ, the acceleration of the abrasive grains by the water takes place with a significantly increased efficiency compared to the AWIJ[19]. The abrasive grains become faster with the AWSJ than with the AWIJ for the same hydraulic power of the system. Therefore, the AWSJ can cut deeper and faster.

ConSus – The abrasive water suspension jet system with continuous abrasive supply[edit]

ConSus lock system for continuous cutting with AWSJ
ConSus lock system for continuous cutting with AWSJ
ConSus abrasive mixing unit for waterjet cutting systems
ConSus abrasive mixing unit for waterjet cutting systems

The patented abrasive water suspension jet system "ConSus“[20] (Continuous Suspension) enables a continuous supply of the abrasive (without air supply) into the pressurised high-pressure vessel via an intermediate vessel by means of a lock process.[21]

The actual high-pressure vessel with the premixed suspension is level-monitored. If the fill level has dropped to a predefined lower level, suspension (abrasive water) is added via a valve from the intermediate vessel under the same high pressure. When the intermediate tank is empty, the valve and the high-pressure water supply line are closed and the intermediate tank is depressurised.

Then a ball valve is opened and the "refill" water-abrasive suspension flows into the intermediate container without air via a hopper. After the ball valve is closed, the intermediate tank is pressurised again via the high-pressure water line so that suspension can be added again as soon as the level in the high-pressure tank drops. In this pressure vessel, there is then a further mixture between water and abrasive suspension.

The water flushes the abrasive out of the high-pressure vessel and carries it up to the suspension nozzle (carbide nozzle), where it is then accelerated together with the abrasive and emerges as a 2-component abrasive water jet for cutting.[22]

Sustainability through improved recyclability of the abrasive used[edit]

Modern waterjet cutting machines are equipped with water and abrasive treatment and the water can be circulated within the system.[23]. The abrasive can reused again after cleaning (removal of the joint discharge material) and after appropriate screening and particle size classification (recycling).

The abrasive can also be filled into the pressure vessel in a moist state for cutting in the was process. In contrast to the AWIJ process, it is not necessary for the abrasive to be in dry and free-flowing form.[24][25] This process advantage enables the abrasive residue to be processed directly at the machine, i.e. directly at the point of origin and reuse[26][27].

Application areas[edit]

Industrial manufacturing[edit]

As early as the 1990s, water-abrasive suspension jet cutting technology was used sporadically in the machining of metallic and non-metallic flat components. In the initial phase, however, the system components were often home-made. As part of a European-funded development project in cooperation with the University of Hanover, a so-called job shop, i.e. a cutting service provider, from Denmark was convinced of the advantages of AWSJ technology at an early stage and carried out cutting tasks with a specially developed system

ConSus cutting 8 mm Ceramic Al203 with purity 98% at cutting speed 40 mm/min
ConSus cutting 8 mm Ceramic Al203 with purity 98% at cutting speed 40 mm/min

Currently, AWSJ technology is used in the field of manufacturing technology, especially for the production of parts made of materials that are difficult to cut or with a large cutting depth (advantage of the high cutting performance of AWSJ) as well as for cutting tasks with a necessary small cutting jet diameter or where sparking must be avoided[28][29]. In addition to the technical advantages, the ecological and economic advantages of the simple reuse of partial quantities of the abrasive used will become increasingly important in the future. In this context, it is to be expected that the users of AWIJ plants will seek a AWSJ system extension or additional AWSJ plant in order to be able to reuse the abrasive waste that has so far been produced as residual material.

A water abrasive suspension jet (WAS or AWSJ or slurryjet) cutting system achieves numerous advantages over AWIJ systems:[30][31]

  • even the hardest materials with a material thickness of up to 1,000 mm can be cut through precisely
  • up to 3 times the cutting speed or an increase in productivity of up to 300 % compared to conventional AWIJ technology[32]
  • up to 70 % lower energy consumption and wear due to the low pressure of only 1,500 bbar
  • improved occupational health and safety due to reduced noise and particle emissions
  • Energy-efficient recycling of 80 % of the abrasive and direct reuse without drying

With the water abrasive suspension jet system "ConSus" (Continuous Suspension), which enables the uninterrupted use of AWSJ technology in industrial production as described above[33], existing AWIJ systems can be upgraded to a water abrasive suspension cutting system or a complete AWSJ system is offered, in each case optionally with an abrasive recycling system and/or water treatment systems[34].

Cutting of fine structures[edit]

Fully integrated AWSJ machine
Fully integrated AWSJ machine

According to the current state of the art, jet diameters of 200 micrometres and more are used for industrial part production using AWIJ. Therefore it is possible to produce the most filigree, previously unfinishable contours on high-performance materials. The machining qualities can be compared to those of wire EDM, whereby a minimum electrical conductivity is not a prerequisite for the machining of the semi-finished product.[35]

For this purpose, a fully integrated AWSJ machine is offered [36], which has the following features:

  • Manufacture of the most filigree, previously unfinishable contours on high-performance materials through reduced beam diameter down to 0.2 mm with significantly higher performance[37][38]
  • fully integrated system technology (incl. high-pressure pump) with a total installation area of 2.5 square metres
  • universal applicability for different processing tasks
  • Lower energy consumption through the use of pump technology with reduced drive power and a max. required water pressure of 1500 bar (150 MPa). (In the AWIJ process, pressure levels of up to 6000 bar (600 MPa) are used as standard[39])
  • Resource conservation through recycling of consumables (see above).
Cutting of tiny parts
Cutting of tiny parts

Disassembly of components in nuclear power plants[edit]

The AWSJ was already used in an early trial at the Kahl experimental nuclear power plant with regard to its applicability and reliability in the dismantling of thick-walled components under water cover.[40] The results of the cutting operations carried out there subsequently led to further applications in the dismantling of nuclear facilities in Europe.t[41]  n advantage is that the mobile cuttindevises c can be operated remotely and are spatially separated from the other central components of thAWSJ systemntandathus t only a few components can be contaminated by radioactive radiation. Since the water cover and the abrasive reflecting from the kerf lead to a rapid clouding of the surrounding water and thus to poor visual monitoring of the cutting process, sensory monitoring devices and processes were developed especially for this area of application[42] which can now also be used in maritime underwater operations.[43]

Bomb disposal[edit]

Video control of cutting process
Video control of cutting process
Installation of cutting device
Installation of cutting device

During missions of the Explosive Ordnance Disposal Service, situations occur time and again in which the fuse of unexploded ordnance to be defused can not at all or only at an unacceptable risk be removed from the bomb with the standard tools available. Under these operating conditions, safe access to the detonator can be cut free by means of a mobile, remotely handled AWSJ cutting device.[44]

In addition to its MACE systems, the Lübeck-based company ANT AG also provides the necessary cutting devices [45], to meet the special requirements for accessing and defusing bombs, grenades, improvised explosive devices such as pipe bombs, suitcase bombs, gas cylinders and car bombs. These cutting guidance systems can be mobile multi-axis handling systems to be set up at the site of operation, controlled e.g. with MACE from a distance of up to 500 m, or also robot-controlled remote handling tools which arrive at the site of operation by means of a "remote operated vehicle" (ROV).

Decommissioning of offshore structures[edit]

The slurryjet (AWSJ) is used for the dismantling of thick-walled components or surface and underwater components made of steel or a mixture of materials (e.g. steel and concrete) for offshore structures such as rigs.[46]. The air-free supply of the jet components by means of high-pressure hoses from above the waterline (from a ship or from the offshore platform[47]) to the respective subsea deployment sites is a decisive success factor. The slurry jet cannot jam or get stuck during cutting. The AWSJ system can be used by means of (remote-controlled) handling systems, but also as a hand-guided system by divers.[48].

In particular, cutting through multistring casings, downhole pipes and platform piles from the inside using a WAS cutting tool (e.g. DCH Downhole Cutting Head or PCH Pile Cutting Head) is a typical area of application in the dismantling of offshore installations in the oil and gas industry.[49][50]. The base structures of offshore wind turbines are dimensioned accordingly large due to the tower heights and the high forces introduced by the rotor blades. When dismantling such structures above and below the waterline (for repair purposes or also when the service life is reached), cutting tools are required that can be used without any problems both in terms of the material thickness present and in terms of any material mix (steel and concrete)[51].

Special applications[edit]

Cutting free a stuck tunnel drilling machine[edit]

In 2015, the steel shield of the tunnel boring machine "Giulia", which had become jammed with a 1.20 metre thick bored pile wall on a construction site in Karlsruhe, was cut free using a water abrasive suspension jet.[52][53]. The mobile AWSJ system was supplemented on site with the necessary handling components.

Submarine (KURSK)[edit]

The accident of the nuclear-powered Soviet submarine "KURSK" is remembered by many people due to the intensive media presence at the time.[54][55] In order to rescue the injured seamen from the submarine or to lift the submarine safely, it was necessary to cut 26 holes in the hull to attach special lifting equipment.[56] According to reports, a water abrasive jet was also used in the process. The abrasive used, with the background of maximum cutting performance, was reported to be diamond grit.[57].Due to the conditions of use, it can be assumed that the abrasive water jet used was a slurry jet.

COBRA extinguishing lance[edit]

The extinguishing system "Cobra" of the company ColdCut-Systems from Sweden works with a pressure of up to 300 bar (30 MPa). The handling system (the so-called lance) is carried by the firefighter directly to the scene of the fire and can be used there to penetrate solid bodies such as doors, walls or metal sheets. The system is used when a fire has ignited in a locked room, container, etc. and no other mechanical solution for access can be realised. A WASS is used for cutting or drilling through the wall, where the abrasive supply can be shut off immediately after the jet exits the inside of the wall. Thus, only pure water is then sprayed through the lance into the cavity. The small droplet size due to the high pressure and the speed of the droplets result in a very high heat absorption capacity. After about seven metres, the jet disintegrates into a cloud of water droplets. The cooling and thus extinguishing effect of the system is greatest at this distance.[58][59]

References[edit]

  1. ^ "Wasser-Abrasiv-Suspensions-Strahl-schneiden (WASS) – Institut für Werkstoffkunde" (in German).
  2. ^ "Measurement and Analysis of Abrasive Particles Velocities in AWSJ", Procedia Engineering (in German), vol. 149, pp. 77–86, 2016-01-01, doi:10.1016/j.proeng.2016.06.641, ISSN 1877-7058, retrieved 2021-07-01
  3. ^ Pressestelle. "Hochleistungsverfahren bezwingt Hochleistungswerkstoffe" (in German).
  4. ^ Prof. Dr.-Ing.Michael Kaufeld, Prof. Dr.-Ing. Frank Pude, Dipl.-ing. Marco Linde (2019-03). "ConSus – DAs Wasser-Abrasiv-Suspensionstrahl-System mit kontinuierlicher Abrasivmittelzufuhr" (PDF). https://studium.hs-ulm.de/de/users/625229/Documents/Ingenieurspiegel%20ConSus_IS_3_2019.pdf (in deutsch). Ingenieur-Spiegel. Band 3-2019. Public Verlagsgesellschaft und Anzeigenagentur mbH, Bingen, S. 23–25. {{cite web}}: Check date values in: |date= (help); External link in |periodical= (help)CS1 maint: multiple names: authors list (link) CS1 maint: unrecognized language (link)
  5. ^ "Wasser-Abrasiv-Suspensions-Strahl-schneiden (WASS) – Institut für Werkstoffkunde" (in German).
  6. ^ NDR. "Bombenentschärfungen: Neue Wasserstrahl-Technik" (in German).
  7. ^ "Decommissioning Project Completed for Middle East Offshore Platform".
  8. ^ "Spektakulärer Robotereinsatz: Stäublis Unterwasser-Roboter zerlegt radioaktive AKW-Bestandteile" (in German). 2021-01-07.
  9. ^ "Wasser-Abrasiv-Injektor-Strahl-schneiden (WAIS) – Institut für Werkstoffkunde" (in German).
  10. ^ Patentschrift des Reichspatentamtes Nr. 430112 vom 19. Juni 1924
  11. ^ "Wasser-Abrasiv-Suspensions-Strahl-schneiden (WASS) – Institut für Werkstoffkunde".
  12. ^ Konrad Mücke. "Suspensionswasserstrahl ist effizienter".
  13. ^ H. Louis, F. Pude, Ch. von Rad, R. Versemann (2007-09), "Abrasive Water Suspension Jet Technology Fundamentals, Application and Developments", Welding in the World (in German), vol. 51, no. 9–10, pp. 11–16, doi:10.1007/BF03266595, ISSN 0043-2288, retrieved 2021-07-01 {{citation}}: Check date values in: |date= (help)CS1 maint: multiple names: authors list (link)
  14. ^ "Abrasive Mixing Units AMU Twin 2500-100".{{cite web}}: CS1 maint: url-status (link)
  15. ^ "AMU offshores spread".{{cite web}}: CS1 maint: url-status (link)
  16. ^ "New Offshore Lifting Unit for our powerful Abrasive Mixing Units (AMU) / safe and efficient cutting".{{cite web}}: CS1 maint: url-status (link)
  17. ^ "Waterjet cutting with ConSus – ConSus".{{cite web}}: CS1 maint: url-status (link)
  18. ^ "ConSus ermöglicht stationären Einsatz des WAS Verfahrens". Österreichische Kunststoffzeitschrift. 2021-04-22.
  19. ^ "Measurement and Analysis of Abrasive Particles Velocities in AWSJ", Procedia Engineering (in German), vol. 149, pp. 77–86, 2016-01-01, doi:10.1016/j.proeng.2016.06.641, ISSN 1877-7058, retrieved 2021-07-01
  20. ^ EUROPÄISCHE PATENTSCHRIFT: EP 3 600 767 B1
  21. ^ Schlütersche Verlagsgesellschaft mbH & Co KG. "Wasser-Abrasiv-Suspensions-schneiden ohne Unterbrechung".
  22. ^ Kaufeld, M.; Pude, F.; Linde, M. (2019-03). "ConSus – Das Wasser-Abrasiv-Suspensionsstrahl-System mit kontinuierlicher Abrasivmittelzufuhr" (PDF). Ingenieur-Spiegel. Band 3-2019. S. 23–25. Public Verlagsgesellschaft und Anzeigenagentur mbH, Bingen. {{cite web}}: Check date values in: |date= (help)CS1 maint: multiple names: authors list (link)
  23. ^ "WKS Wasserkreislaufsystem".
  24. ^ Qingshan Ma, Jie Lin, Kaining Yang, Han Xie, Chuwen Guo (2021-05), "Experimental study on abrasive recycling in cutting with abrasive suspension water jet", The International Journal of Advanced Manufacturing Technology (in German), vol. 114, no. 3–4, pp. 969–979, doi:10.1007/s00170-021-06921-x, ISSN 0268-3768, retrieved 2021-07-01 {{citation}}: Check date values in: |date= (help)CS1 maint: multiple names: authors list (link)
  25. ^ WARDJet. "Waterjet Abrasive Recycling System".
  26. ^ Thomas Bergs, Manuel Schüler, Tim Herrig, Jan Fernolendt, Marco Linde (2021), "Systematic Change of Abrasive Size Distribution", Advances in Water Jetting (in German), Cham: Springer International Publishing, pp. 39–48, doi:10.1007/978-3-030-53491-2_4, ISBN 978-3-030-53490-5, retrieved 2021-07-01{{citation}}: CS1 maint: multiple names: authors list (link)
  27. ^ "ARU Abrasive Recycling Unit for waterjet cutting systems".{{cite web}}: CS1 maint: url-status (link)
  28. ^ Schlütersche Verlagsgesellschaft mbH & Co KG. "Wasserstrahlschneiden: Suspension unter Hochdruck".
  29. ^ Konrad Mücke. "Suspensionswasserstrahl ist effizienter".
  30. ^ "Hohe Schneidleistung mit Wasser Abrasiv Suspension".
  31. ^ Schlütersche Verlagsgesellschaft mbH & Co KG. "Wasser-Abrasiv-Suspensions-schneiden ohne Unterbrechung".
  32. ^ Kaufeld, M.; Pude, F.; Linde, M., "ConSus – Das Wasser-Abrasiv-Suspensionsstrahl-System mit kontinuierlicher Abrasivmittelzufuhr", Ingenieur-Spiegel (in German), vol. 3–2019, Bingen: Public Verlagsgesellschaft und Anzeigenagentur mbH, pp. 23-25{{citation}}: CS1 maint: multiple names: authors list (link)
  33. ^ Schlütersche Verlagsgesellschaft mbH & Co KG. "Wasser-Abrasiv-Suspensions-schneiden ohne Unterbrechung".
  34. ^ "Waterjet cutting with ConSus – ConSus".{{cite web}}: CS1 maint: url-status (link)
  35. ^ TU Chemnitz Pressestelle. "Hochleistungsverfahren bezwingt Hochleistungswerkstoffe".
  36. ^ "EcoWASP1500".
  37. ^ Pressestelle. "Hochleistungsverfahren bezwingt Hochleistungswerkstoffe".
  38. ^ "EcoWASP1500".
  39. ^ "BFT Pumps".
  40. ^ "Kerntechnik".
  41. ^ "Spektakulärer Robotereinsatz: Stäublis Unterwasser-Roboter zerlegt radioaktive AKW-Bestandteile". 2021-01-07.
  42. ^ H. Louis, D. Peter, F. Pude, R. Versemann (2005), "FLEXIBLE AND MOBILE ABRASIVE WATERJET CUTTING SYSTEM FOR DISMANTLING APPLICATIONS", Proceedings of the 2005 WJTA American Waterjet Conference (in German), Houston/USA, pp. 3B-4 {{citation}}: line feed character in |title= at position 53 (help)CS1 maint: multiple names: authors list (link)
  43. ^ Süddeutsche Zeitung. "Abbau des AKW Brunsbüttel: „Auf dem Weg zur grünen Wiese"".
  44. ^ NDR. "Bombenentschärfungen: Neue Wasserstrahl-Technik".
  45. ^ "Cutting devices for bomb disposal".{{cite web}}: CS1 maint: url-status (link)
  46. ^ "Decommissioning Project Completed for Middle East Offshore Platform".
  47. ^ "Cutting of multi-string casings".{{cite web}}: CS1 maint: url-status (link)
  48. ^ "Cutting".
  49. ^ "DCH – The latest technology for the dismantling of pipes in the offshore sector".
  50. ^ "Abrasive water jet cutting".
  51. ^ "AQUATEC-GROUP Hochdruck-Dienstleister > Rückbau WKA – Hooksiel".
  52. ^ ka-news (2015-07-03). "Tunnelbohrer „Giulia" steckt fest: Jetzt soll Wasser weiterhelfen | ka-news".
  53. ^ "Babendererde Engineers".{{cite web}}: CS1 maint: url-status (link)
  54. ^ Peggy Chalmers (2002-05-01), "Feature Focus: Offshore Innovations: Raising the Kursk", Mechanical Engineering (in German), vol. 124, no. 05, pp. 52–55, doi:10.1115/1.2002-May-3, ISSN 0025-6501
  55. ^ "U-Boot-Katastrophe: Kursk-Bergung beginnt: Spezialtaucher untersuchen Wrack", FAZ.NET (in German), ISSN 0174-4909, retrieved 2021-06-30
  56. ^ Mammoet. "SignatureCase Kursk | Mammoet".
  57. ^ Staff and agencies (2000-10-26). "Note reveals 23 survived initial Kursk blast".
  58. ^ "Einsatzmöglichkeiten des »Cobra«-Löschsystems – Feuerwehr".
  59. ^ "Coldcut Cobra".{{cite web}}: CS1 maint: url-status (link)
Retrieved from "https://en.wikipedia.org/w/index.php?title=User:WJ-Engineer/sandbox&oldid=1057888415"