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
  • B63H11/08—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
  • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
  • B63H5/08—Arrangements on vessels of propulsion elements directly acting on water of propellers of more than one propeller
  • B63H5/10—Arrangements on vessels of propulsion elements directly acting on water of propellers of more than one propeller of coaxial type, e.g. of counter-rotative type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
  • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
  • B63H5/125—Arrangements on vessels of propulsion elements directly acting on water of propellers movably mounted with respect to hull, e.g. adjustable in direction, e.g. podded azimuthing thrusters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
  • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
  • B63H5/14—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in non-rotating ducts or rings, e.g. adjustable for steering purpose
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
  • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
  • B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
  • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
  • B63H5/125—Arrangements on vessels of propulsion elements directly acting on water of propellers movably mounted with respect to hull, e.g. adjustable in direction, e.g. podded azimuthing thrusters
  • B63H2005/1254—Podded azimuthing thrusters, i.e. podded thruster units arranged inboard for rotation about vertical axis
• • 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
  • B63H11/08—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type
  • B63H2011/084—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type with two or more pump stages
  • B63H2011/085—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type with two or more pump stages having counter-rotating impellers

Definitions

• This invention relates to a drive with contra rotating propel ⁇ lers, where the shaft of the outer propeller is supported by bearings in the hollow shaft of the inner propeller.
• contra rotating propellers one left handed and one right handed propemler rotating on two concent ⁇ ric shafts in opposite directions.
• the physical function of the system is based on the fact that the rotational losses of the forward propeller may be utilized in the aft propeller whereupon the efficiency of the system may be usually improved by 5 to 10 per cent as com ⁇ pared with conventional propellers.
• the traditional applicati ⁇ on of contra rotating propellers has been the torpedoes, where besides a good efficiency a troque-free propulsion system is required.
• Other advantages of contra rotating propellers as compared with conventional ones are a smaller propeller diame ⁇ ter, better cavitation characteristics,, a smaller vibration . level and better steering qualities.
• Heavily loaded propellers suffer from a poor efficiency, e.g. trawlers and tugs must work with effi ⁇ ciencies around 40 per cent. If the power is divided between several propellers, the efficiency is improved, but the flow conditions ' at a propeller far aside from the center line of the vessel are worse than those at a propeller midships, and the total advantage is lost.
• Contra rotating propellers are known as an efficient propulsion device of high speed craft. Their efficiency is based besides
• the aim of the present invention is to create an even more ef ⁇ ficient propulsion device than above by which especially hea ⁇ vily loaded drives may designed even more efficient.
• This is achieved by utilizing at least four propellers.
• four propellers are ' utilized that are arranged as pairs such, that one pair is pulling while the other one is pushing, whereas the propellers of both pairs ro ⁇ tate in opposite directions. With this four propeller drive a sufficient division of the power is obtained, and a fuel sa ⁇ ving of 20 to 25 per cent may be achieved at heavily loaded vessels.
• the rotational losses may be utilized more effi ⁇ ciently than in any known device.
• the propeller dia ⁇ meters may be kept small but the thrust will increase due to a greater number of propellers. In this case it is therefore ea ⁇ sy to ' mount the drive in the bottom of the vessel. Because of the small propeller diameters the drive will not form an ex ⁇ cessive appendage outside the bottom of the vessel.
• the drive in an easy way on a compass thruster to act as an active rudder, it may be mounted in a nozzle or a duct in the bottom of vessel to act as a water jet.
• the drive comprises several propellers it may be de ⁇ signed for various applications in a favourable way.
• the pro ⁇ peller diameters are chosen such that the forward most propel ⁇ ler diameter is the largest and the aftermost one the smallest in order to keep the propellers inside the flow contraction.
• various speeds of rotation may be chosen by a proper gear box arrangement using less speed for the forward most propeller and more speed for the aftermost one.
• the num ⁇ ber of blades may be similarly varied with the forward most propeller having the smallest number of blades and the after- most propeller the largest one.
• the pitch distribution may be varied as well depending on the application. The invention is described in more detail by referring to the accompanying dra ⁇ wings where
• Fig. 1 shows a preferred embodiment of the invention in prin ⁇ ciple
• Fig. 2 shows a drive in accordance with the invention as a wa ⁇ ter jet
• Fig. 3 shows a drive in accordance with the invention mounted in the nozzle of a compass thruster
• Fig, 4 shows a further embodiment of the invention.
• a preferred embodiment of the invention is mounted at the stern of a vessel 1, and the drive is coupled with a right angle gear box to a prime mover (not shown).
• the output shaft 7 of the prime mover has been coupled by means of a be ⁇ vel gear box to a through the bottom of the vessel mounted transmission shaft 8 that ends to a bevel gear box inside the pod 2 of the drive.
• the gear box comprises the bevel gears 9 and 10 on the transmission shaft 8 the said gears being situa ⁇ ted at a distance from each other, and the supporting bearings of the transmission shaft 8 are located in the vicinity.
• both shafts of the pro- peller pairs 3, 4 and 5, 6 are ended.
• the shafts 13 of the ou ⁇ ter propellers 3, 6 are supported by bearings inside the hol ⁇ low shafts 14 of the inner propellers 4, 5.
• the outer propellers 3 and 6 therefore rotate in opposite
• the drive may be mounted in a duct at the stern of the vessel, whereupon the drive will act as a water jet (Fig. 2).
• FIG. 4 Another embodiment of the invention is shown in Fig. 4, where two double propeller drives are mounted in the bottom of the vessel after each other.
• this application is simi ⁇ lar to the one presented in Fig. 1 with the exception that the propeller pairs are mechanically separated from each other. However, physically they operate quite similarly.
• Fig. 4 all propellers are pushing ones. It goes without saying that the drives may be arranged such that one pair of propellers is pushing and the other one is pulling.
• the power of the prime mover may thus be divided between four propellers resulting in a smaller size of the individual pro ⁇ pellers without reducing the overall thrust of the drive.
• the rotational losses may be effectively eliminated resulting in a better efficiency than in any conventional device.
• the drive is therefore ideally suited for heavy drift with another additional advantage viz. that the drive as whole may be designed to suit any individual application in a best possible way. In that case many variations may be needed, whe ⁇ re the variables may be the propeller diameters, the number of
• TITUTE SHEET blades the speed of rotation of the propellers, the pitch distributions, the directions of rotation etc.
• the application of the drive is usually such that, as seen from the bow of the vessel, the diameter of the first propel ⁇ ler is largest, the number of blades is least and the speed of rotation is least, and these relations vary towards the last propeller such, that the diameter of the last propeller is le ⁇ ast, the number of blades is largest and the speed of rotation is largest.
• the directions of rotation are chosen such that the side for ⁇ ces when the vessel is performing a turn diminish.
• the speeds of rotation may be additionally chosen somewhat different from each other to assist to solve lubrication and vibration problems.
• the drive is extremely well suited for heavily loaded applica ⁇ tions like tugs, trawlers and cargo ships, but other applica ⁇ tions are, of course, possible as well.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Gear Transmission (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
• Vehicle Body Suspensions (AREA)
• Power Steering Mechanism (AREA)
• Steering Control In Accordance With Driving Conditions (AREA)
• Hydraulic Turbines (AREA)
• Toys (AREA)
• Control Of Electric Motors In General (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8519497

Family Applications (1)

Country Status (10)

Cited By (7)

Families Citing this family (2)

Citations (6)

Family Cites Families (2)

• 1984
  • 1984-08-22 FI FI843301A patent/FI75128C/fi not_active IP Right Cessation
• 1985
  • 1985-07-08 AU AU46397/85A patent/AU4639785A/en not_active Abandoned
  • 1985-07-08 JP JP60503415A patent/JPS61503022A/ja active Pending
  • 1985-07-08 WO PCT/FI1985/000065 patent/WO1986001483A1/en active Application Filing
  • 1985-07-08 GB GB8703462A patent/GB2187516B/en not_active Expired
  • 1985-07-08 NL NL8520216A patent/NL8520216A/nl unknown
  • 1985-07-08 DE DE19853590393 patent/DE3590393T1/de not_active Withdrawn
• 1986
  • 1986-04-16 DK DK174786A patent/DK174786A/da unknown
  • 1986-04-18 NO NO861552A patent/NO861552L/no unknown
• 1987
  • 1987-02-20 SE SE8700721A patent/SE8700721L/xx not_active Application Discontinuation

Patent Citations (6)

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