Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H11/00—Marine propulsion by water jets
  • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
  • B63H11/04—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H11/00—Marine propulsion by water jets

Definitions

• the invention also concerns a water jet comprising a water inlet which leads from the sea to a pump housing which contains at least a bearing arrangement and an impeller.
• Water jets are used to a certain extent in the propulsion of ships.
• a water jet comprises a water inlet which passes water from the ship's underside to a pump which is located in a pump housing and driven by a motor.
• a water outlet directed backwards from the pump housing produces a backwardly directed water jet which propels the ship forwards.
• the pump housing In known water jets the pump housing is normally located in the area of or immediately below the waterline, inside or aft of the ship's stern.
• the pump housing is connected to a guide apparatus to give the water jet the most favourable velocity and direction with a view to the propulsion, and a steering apparatus located behind the guide apparatus, to steer the ship by altering the direction of the water jet.
• the water inlet and the motor are provided inside the ship.
• the pump housing is designed in one piece, with a forwardly directed axial opening connected to the water inlet, and a backwardly directed axial opening connected to the guide apparatus.
• the ship has to be placed in dry dock or a slip, and the connection between the pump housing and the water inlet is loosened, thus enabling the pump housing with the guide apparatus and the steering apparatus to be lifted away from the ship. This is an expensive and time-consuming operation, which restricts the desire to use water jets.
• US 3 030 909 describes a water jet where the pump housing with the impeller are located inside the ship, immediately in front of the ship's sternpost.
• the steering apparatus is located outside the ship, while the guide apparatus is located in an intermediate position.
• the ship's centre of gravity is thereby located further forward than with those water jets in which the pump housing is located aft of the ship's stern, but the maintenance of this water jet is cumbersome, and will require the use of a slip or dry dock to dismantle the pump housing.
• the object of the invention is to provide a method for maintenance of a water jet and a water jet which is not encumbered by the above-mentioned disadvantages.
• the pump housing's mechanical components are specified as an impeller and a bearing arrangement. This should not be perceived as limiting for the invention, since the pump housing naturally comprises far more components, and moreover the content of components will vary between different designs.
• figs. 3-5 are side views of the water jet, where parts of the pump housing's mechanical components are in the process of being lifted out, and figs. 6-7 are side views of the water jet, used together with blocking bodies for water inlet and water outlet.
• Figs. 1 and 2 illustrate a water jet 1 with a pump housing 3.
• the water jet 1 is envisaged located in the rear part of a ship, near the ship's stern.
• a channel- shaped water inlet 2, defined by walls 17, passes water from the sea 18 under the ship to the pump housing 3.
• the pump housing 3 contains mechanical components in the form of an impeller 6, see fig. 3, which supplies kinetic energy to the water and forces the water out in a water outlet 13, and a bearing arrangement 5 which forms the impeller's mounting, and which consists of a bearing housing, a rotating stern tube, a mechanical seal, bearings and other mechanical components.
• a not shown motor drives the bearing arrangement 5 and the impeller 6 via a substantially horizontal drive shaft 12.
• a guide apparatus 21 is located in the water outlet 13, behind the pump housing 3, to guide the water into a backwardly directed water jet, and a steering apparatus 22 is located behind the guide apparatus 21 to steer the water jet and thus steer the ship.
• the guide apparatus 21 and the steering apparatus 22 do not form part of the actual invention, and will not be described in more detail.
• the pump housing 3 is divided into an upper part
• the upper and lower parts of the pump housing are provided with flanges, 14 and 15 respectively, which are bolted together with bolts 16 in a known per se manner, but this connection between the upper and lower parts of the pump housing may of course be implemented in other ways.
• connections in the illustrated embodiment are also designed as bolted flanges.
• the coupling 1 1 may be in the form of a spline coupling, and in this case it may be released from the drive shaft 12 and the impeller 6 by axial displacement of the drive shaft and/or the impeller.
• Figs. 4 and 5 show the lifting out of the impeller 6 and the bearing arrangement 5 respectively.
• an additional feature of the method is that the part of the ship where the pump housing is located is raised, preferably by ballasting/deballasting of the ship, thus causing the water level in the pump housing to sink.
• Fig. 6 shows how the water inlet 2 can be closed by a blocking body 30, shown here in the form of an elastic bladder, which through a hatch 19 in the walls 17 of the water inlet can be inserted into the water inlet 2 before the pump housing 3 is opened, under the influence of a fluid pressure which is supplied through a hose 37, being extended to press sections of the blocking body 30 against the walls 17 of the water inlet.
• the water outlet 13 will be closed for the inflow of water from the sea outside the ship by having a section of the water outlet located higher than the surface of the water, and in this case a closing of the water outlet is unnecessary. In a further preferred embodiment of the invention, however, the water outlet is also closed, thus preventing sea water from gaining access to the pump housing. Fig.
• FIG. 7 shows how the water outlet 13 can be closed by a blocking body 31 , shown here in the form of a hollow elastic ring, which is located in a section 32 of the water outlet 13 with an annular cross section, defined by a centrally located orifice pin 33 and an orifice ring 34 provided around the circumference, under the influence of a fluid pressure, being extended to press sections of the blocking body 31 against the orifice pin 33 and the orifice ring 34.
• a blocking body 31 shown here in the form of a hollow elastic ring, which is located in a section 32 of the water outlet 13 with an annular cross section, defined by a centrally located orifice pin 33 and an orifice ring 34 provided around the circumference, under the influence of a fluid pressure, being extended to press sections of the blocking body 31 against the orifice pin 33 and the orifice ring 34.
• the water outlet In a second embodiment of the water outlet, where the orifice pin is withdrawn, with the result that it does not form a centrally located section in the water outlet, the water outlet can be closed by a ball-shaped blocking body.
• Water remaining in the pump housing can be drained away by known means, such as by opening a drain plug 7 in the bottom of the pump housing.
• the invention results in a greater area of application for the water jet.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Hydraulic Turbines (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19899722

Family Applications (1)

Country Status (5)

Cited By (4)

Citations (4)

• 1996
  • 1996-08-19 NO NO963452A patent/NO963452L/no unknown
• 1997
  • 1997-08-19 WO PCT/NO1997/000209 patent/WO1998007618A1/en active Application Filing
  • 1997-08-19 AU AU40350/97A patent/AU713950B2/en not_active Ceased
• 1999
  • 1999-02-18 SE SE9900552A patent/SE9900552L/sv not_active Application Discontinuation
  • 1999-02-18 FI FI990350A patent/FI990350A/sv unknown

Patent Citations (4)

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