US3549271A - Backflow recovery propeller device - Google Patents

Backflow recovery propeller device Download PDF

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Publication number
US3549271A
US3549271A US764575A US3549271DA US3549271A US 3549271 A US3549271 A US 3549271A US 764575 A US764575 A US 764575A US 3549271D A US3549271D A US 3549271DA US 3549271 A US3549271 A US 3549271A
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Prior art keywords
propeller
blade
backflow
recovery
main
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Expired - Lifetime
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US764575A
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English (en)
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Hidetsugu Kubota
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/28—Other means for improving propeller efficiency
    • 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

Definitions

  • a propeller device comprising a fixed main propeller and a freely rotatable backflow recovery propeller, both operated in the same direction on a common shaft.
  • the recovery propeller has a collision surface for the backflow current of a high pitch and the opposite surface thereof is effectively of a low pitch. These two surfaces converge into a semicircular shaped leading edge whereby the blade thickness ratio of the backflow propeller progressively increases towards the end of the blade.
  • Such a construction can substantially convert the backflow energy into a recovered propelling force.
  • the present invention relates to a backflow recovery propeller device.
  • An object of the present invention is to provide a propeller device in which the inertia of the twisted fluid flow being produced by the fixed main screw propeller is substantially utilized.
  • Another object is to provide a freely rotatable recovery screw propeller having a collision surface for the backflow current of a high pitch and the opposite surface thereof is thus effectively of a low pitch.
  • FIG. 1 is a side view of an embodiment of the present invention
  • FIG. 2 is a front view
  • FIG. 3 is a section of blade thickness ratio taken along line IIIIII of FIG. 1, showing a variation of blade thickness.
  • 1 shows a propeller shaft, 2 a fixed main screw propeller, 3 a freely rotatable recovery screw propeller, 9 a cap, A is a direction of rotation and D a distance or gap between the main propeller 2 and the freely rotatable recovery propeller 3.
  • 2a and 2b show leading and trailing edges of the main blade.
  • 3a and 31) show also leading and trailing edges of the recovery blade.
  • 3a and 3b show the smallest and the largest recovery blade thickness portion, the former being in a zone of stationary fluid and the latter in a zone of the rotating flow or twisted flow.
  • Sal shows the end portion of the smallest thickness blade.
  • 3171 and 3172 show the end portions of the inner blade.
  • 3b3 shows a colliding surface.
  • 3174 shows a semicircular shaped portion for the leading edge.
  • the recovery propeller device consists of the two screw propellers 2, 3 mounted on the shaft 1.
  • the contour of the blade of the conventional main screw propeller 2 is made similar to the substantially straight line of the leading edge 3a of the adjacent recovery screw propeller 3.
  • the trailing edge 2b of the main screw propeller 2 is made in a substantially straight line and slightly spaced from the leading edge 3a of the recovery screw propeller 3.
  • the main screw propeller is fixed on the propeller shaft 1 and operates as a conventional type blade propeller.
  • the freely rotatable recovery screw propeller 3 adjancent the main propeller 2 3,549,271 Patented Dec. 22, 1970 is movably mounted on bearings on the shaft 1.
  • a hub in both sides of which sea water is prevented from flowing in by special oil seals.
  • the lubrication thereof is eifected by a simple lubricating hydraulic system or by a sea water lubrication system having a special nonabsorbing synthetic resin.
  • the feature of the recovery blade includes making both sides of a helical configuration and thus forming a colliding surface 3113 for receiving the twisted backflow. Its opposite surface, i.e., a propulsion producing advance surface, or a backflow colliding surface is made in a substantially straight line.
  • a propulsion producing advance surface or a backflow colliding surface is made in a substantially straight line.
  • the pitch of the advance surface of the recovery blade may preferably be about five times large as that of the main blade. This relatively high pitch ratio is theoretical but is reasonable.
  • the present invention comprises a backflow recovery screw propeller in which the opening ends of the helical surface of the advance surface and the helical surface or plain surface of the backflow colliding surface converged into a semicircular shaped leading edge.
  • the helical surfaces of the left and right sides thus have elevation angles that are combined into one blade.
  • a twisted backflow torque is absorbed by the backflow colliding surface to produce a rotating force.
  • the driving surface renders a high pitch while the advance surface a low pitch so as to obtain an effective propulsion force.
  • the recovery screw propeller is arranged to form in a zone in the twisted rotating flow that is defined by the diameter of the main screw propeller and is arranged to have the smallest in blade thickness within the stationary fluid. Consequently the main blade produces an effective propulsion force.
  • a conventional main screw propeller having blades of a thin thickness is used as the secondary freely rotating screw propeller, the propulsive force is substantially cancelled by the thrust produced opposite to the propelling direction which is produced on the backflow colliding surface.
  • the secondary propeller will be thus moved in the opposite direction, even if the pitch ratio thereof is about two times that of the main propeller. In this case, efficiency will increase somewhat at about the slip ratio, but since the efficiency will be down, the use of said secondary propeller is virtually impossible at the normal slip ratio.
  • the secondary propeller with thin blades is obviously small in blade thickness ratio and carries away backward. There is produced an opposite thrust substantially cancelling the propulsive thrust on the rotating advance surface and definitely does not increase the efliciency.
  • the effective resistance is produced by mutual collision of the fluid between both propellers and the energy which would be lost in the backflow is substantially recovered.
  • total propulsion efliciency is raised.
  • the rotating direction of the main screw propeller and of the recovery screw propeller are the same.
  • the advance surface of the screw propeller blade producing the more effective thrust is given the necessary rotating power factor to absorb entirely the backflow torque. This is suitable in the /8%() rotating rate of the main screw propeller.
  • both sides converge, as described above, on the opening in the backflow colliding surface and the leading edge constitutes a semicircular shaped portion.
  • the blade thickness ratio is made small atthe root and large at the blade end.
  • a pitch. of about five times larger than as that of the main propeller in a slip ratio situation of about.20% for the propeller device a pitch is selected of about four times larger than of the main propeller; In a slip ratio of about a pitch is selected of about"3.5 times larger than that of the main propeller. In slip ratio about Of course blade area ratio and the like must be considered.
  • the change of bladethickness ratio shownin FIG. 1 makes a colliding surface of .the backflow a surface coincided with the advance surface, plain surface in axial direction or the helical surfaces of both left and right sides.
  • blade thickness ratio is made the smallest, considering that in a zone outside the diameter of the main blade there in no substantial effect on the backflow.
  • the advance propelling surface can determine a pitch by the backflow recovery and thus a slip ratio of the highest eificiency of the propeller is achieved.
  • the reason why the leading edge of the recover blade propeller has a semicircular configuration and' not a tapered aerofoil is that if an aerofoil is used, the backflow colliding surface becomes increasingly large and flows in the opposite direction to produce a harmful resistance.
  • a propeller device comprising a power operated shaft having a hub portion, a main screw propeller axially and rigidly mounted on said shaft, a backflow recovery screw propeller axially positioned adjacent said main propeller and mounted to rotate relatively free on said shaft, a cap member axially positioned adjacent said recovery propeller and mounted on one end of said shaft, said main and recovery propellers operatively rotated in the same direction, said recovery propeller having helical shaped surfaces on both sides thereof, said sides converging to form a leading edge having a semicircular configuration, said recovery propeller having a thickness in the longitudinal direction that progressively increases more than one half of the longitudinal distance from the hub portion to the propeller end, the longitudinal distance nearest the end of the propeller having a constant uniform thickness of substantially less than any of the progressively increasing portion whereby the structure of the recovery propeller will substantially convert the backflow force produced thereby into a forward recovered propelling force.

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  • 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)
  • Toys (AREA)
US764575A 1967-10-12 1968-10-02 Backflow recovery propeller device Expired - Lifetime US3549271A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6555167 1967-10-12

Publications (1)

Publication Number Publication Date
US3549271A true US3549271A (en) 1970-12-22

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ID=13290244

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Application Number Title Priority Date Filing Date
US764575A Expired - Lifetime US3549271A (en) 1967-10-12 1968-10-02 Backflow recovery propeller device

Country Status (7)

Country Link
US (1) US3549271A (enrdf_load_stackoverflow)
DE (1) DE1801813A1 (enrdf_load_stackoverflow)
FR (1) FR1589036A (enrdf_load_stackoverflow)
GB (1) GB1250197A (enrdf_load_stackoverflow)
NL (1) NL6814500A (enrdf_load_stackoverflow)
SE (1) SE341147B (enrdf_load_stackoverflow)
SU (1) SU386498A3 (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4381901A (en) * 1979-08-17 1983-05-03 Labudde Russell G Anti-cavitation marine propeller
US4623299A (en) * 1984-01-14 1986-11-18 Harmstorf Ag Driving arrangement for watercraft
US4767269A (en) * 1984-11-29 1988-08-30 Ab Volvo Penta Rotor system, particularly a boat propeller system
US20130129514A1 (en) * 2011-11-18 2013-05-23 Becker Marine Systems GmgH & Co. KG Propeller arrangement, in particular for watercraft
CN107867382A (zh) * 2017-10-16 2018-04-03 重庆交通大学 一种螺旋桨装置
US11713101B2 (en) 2020-12-04 2023-08-01 Jeffrey L. HATHAWAY Propeller hubcap

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3202862C2 (de) * 1982-01-29 1984-04-12 Metronic Electronic GmbH, 7210 Rottweil Luftsprudelmassagegerät
US4571192A (en) * 1983-11-09 1986-02-18 Allied Corporation Self propelled spherical vehicle
DE3931489C2 (de) * 1989-09-21 1994-09-01 Metrax Gmbh Sprudelmatte für ein Luftsprudelmassagegerät
RU2212355C2 (ru) * 2001-06-15 2003-09-20 Волхонов Владислав Иванович Вращающийся контрвинт
RU2291812C1 (ru) * 2005-06-06 2007-01-20 Владислав Иванович Волхонов Вращающийся контрвинт
WO2011144239A1 (en) 2010-05-19 2011-11-24 Wärtsilä Finland Oy Rotational energy recovery appendage

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH91268A (fr) * 1919-03-04 1921-10-17 Etienne Oehmichen Procédé pour améliorer le rendement d'une hélice et dispositif pour la mise en pratique du procédé.
GB332124A (en) * 1928-10-01 1930-07-17 Percival Edwin Mcneil Improvements in screw propulsion
US2126221A (en) * 1936-11-25 1938-08-09 John W Sessums Aircraft propeller unit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH91268A (fr) * 1919-03-04 1921-10-17 Etienne Oehmichen Procédé pour améliorer le rendement d'une hélice et dispositif pour la mise en pratique du procédé.
GB332124A (en) * 1928-10-01 1930-07-17 Percival Edwin Mcneil Improvements in screw propulsion
US2126221A (en) * 1936-11-25 1938-08-09 John W Sessums Aircraft propeller unit

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4381901A (en) * 1979-08-17 1983-05-03 Labudde Russell G Anti-cavitation marine propeller
US4623299A (en) * 1984-01-14 1986-11-18 Harmstorf Ag Driving arrangement for watercraft
US4767269A (en) * 1984-11-29 1988-08-30 Ab Volvo Penta Rotor system, particularly a boat propeller system
US20130129514A1 (en) * 2011-11-18 2013-05-23 Becker Marine Systems GmgH & Co. KG Propeller arrangement, in particular for watercraft
US9328613B2 (en) * 2011-11-18 2016-05-03 Becker Marine Systems Gmbh & Co Kg Propeller arrangement, in particular for watercraft
CN107867382A (zh) * 2017-10-16 2018-04-03 重庆交通大学 一种螺旋桨装置
US11713101B2 (en) 2020-12-04 2023-08-01 Jeffrey L. HATHAWAY Propeller hubcap

Also Published As

Publication number Publication date
FR1589036A (enrdf_load_stackoverflow) 1970-03-16
SE341147B (enrdf_load_stackoverflow) 1971-12-13
NL6814500A (enrdf_load_stackoverflow) 1969-04-15
SU386498A3 (enrdf_load_stackoverflow) 1973-06-14
GB1250197A (enrdf_load_stackoverflow) 1971-10-20
DE1801813A1 (de) 1969-04-30

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