WO1993001085A2 - Marine propulsive device comprising concentric and contra-rotating propellers and ships equipped with such device - Google Patents

Abstract

Marine propulsive device (1) comprising two concentric and contra-rotating propellers (5, 6), rotating at the same speed but in opposite directions, with reversed pitches, said propellers (5, 6) being driven by two primary shafts (3, 4) from either two thermal engines (21, 22) rotating in opposite directions and, each driving a primary shaft, or from a cam engine (2) comprising two concentric primary shafts (3, 4) rotating at the same speed but in opposite directions, such drive means preventing any reaction torque of the ship (1) about the propeller axis (5, 6), the torques of the propellers (5, 6) and of the or both engines. The device is characterized in that the concentric and contra-rotating propellers (5, 6) are placed within a cylindrical shroud, thereby avoiding cavitation and the formation of vortexes generated by each propeller, the shroud (7) being arranged such that its water outlet walls (7) constitute a thrust reverser by closing the water outlet and opening either in two parts or in corolla shape in order to reverse the direction of water flow and provide reverse thrust.

Description

PROPULSION DEVICE FOR VESSELS COMPRISING CONCENTRIC AND CONTRA-ROTATING PROPELLERS AND VESSELS EQUIPPED WITH SUCH A DEVICE.

The present invention relates to a new type of propulsion device for a ship (term taken in the broad sense and designating both surface ships and submarines); it also relates to a new type of ship fitted with such a propulsion device.

The propulsion of ships and submarines is, to date, generally ensured by conventional propellers, the main defect of which is a loss of efficiency as a result of the vortices which are created by the rotation of these. The same is true of the shape of submarines and ships creating eddies and waves causing loss of performance. In addition, the reaction torques induced by the engine and the propeller create piloting difficulties.

Some boats already use concentric and counter-rotating propellers, but the motor drives only one motor shaft rotating in one direction and it is a system of pinions and planetary gears which drives the second propeller in the opposite direction. The engine therefore has a reaction torque which tends to turn the boat around the axis of the engine as in the case of simple propellers and therefore poses driving difficulties for the pilot. As appears from the publication published in "" SHIPBUILDING AND SHIPPING RECORD ", and more particularly of FIGS. 1, 3 and 5 of this document, it has been proposed to make a ship propulsion device comprising two concentric propellers and contra- rotary, rotating at the same speed but in the opposite direction, with reversed steps, said propellers being driven by two drive shafts, coming either from two heat engines, one of which rotates in opposite directions to the other, each driving a drive shaft, either of a cam engine having the characteristic of comprising two concentric drive shafts, rotating at the same speed but in opposite directions, such a drive making it possible to suppress any reaction torque of the ship around the axis of the propellers, the couples of rotation of the propellers being zero as well as those of one or both engines.

The solutions proposed in this document however still have drawbacks, given the fact that the propellers generate vortices which can cause cavitation phenomena. Furthermore, such propulsion systems complicate the maneuvers of the ship (reversing the direction of travel, tacking, etc.).

However, we have found, and this is the subject of the present invention, an improvement made to such a propulsion system which makes it possible to remedy the main drawbacks thereof by increasing the propulsion efficiency, by reducing the losses due eddies and vortices, also improving the efficiency of the propellers and finally, which facilitates maneuvers. The invention therefore relates to an improvement made to a ship propulsion device comprising two concentric and counter-rotating propellers of the aforementioned type, which is essentially characterized in that the concentric and counter-rotating propellers are placed inside a cylindrical hull making it possible to avoid cavitation and the formation of vortices generated by each propeller and which is arranged in such a way that the outlet walls of this hull constitute a thrust reverser by closing the water outlet and opening either in two, either in corolla, to reverse the direction of water flow and constitute the reverse gear.

According to other additional characteristics in accordance with the invention:

the hull which envelops the two counter-rotating propellers is cylindrical at the height of the two propellers, then becomes square or rectangle so that the upper and lower horizontal sides are fixed, integral with the hull, and the straight vertical sides and left are movable around a vertical axis, resting on the horizontal sides, so that the pilot can, according to his order, transform this hull, either in reverse gear, or in a means of lateral displacement of the ship , either by rudder by changing the angle of the water outlet;

- the two concentric and counter-rotating propellers are placed inside a duct connecting the bow to the stern of the ship or submarine, so as to improve propulsion; - when such a device is implemented on a submarine, the front, the center and the rear of said submarine have substantially the same dimensions, so that the flow d can be circulated water driven by the propellers in a duct closed by the walls of the submarine and an outer casing in order to absorb the volume of water generated by the displacement of the submarine, and thus limit the turbulence of exit. The advantages provided by the invention and other additional characteristics will become more clearly apparent from the following description, which is illustrated by the appended diagrams in which:

- Figures 1 and 2 schematically illustrate the state of the prior art, Figure 1 being a plan view of two heat engines controlling two counter-rotating propellers, and Figure 2 a longitudinal sectional view of a ship equipped with these counter-rotating propellers;

- Figures 3 to 9 are schematic views of a ship propulsion assembly produced in accordance with the invention, and in which:

. Figure 3 is a longitudinal sectional view of the ship equipped with these counter-rotating propellers provided with a cylindrical hull, the water outlet walls, on the order of the pilot, are transformed into a reverser;

. FIG. 4 is a perspective view of the hull, cylindrical at the height of the counter-rotating propellers, and square or rectangle at the outlet so as to constitute either a means of lateral displacement of the ship, or a thrust reverser, or a rudder;

. Figure 5 is a plan view of the hull flaps allowing movement of the ship; . Figure 6 is a plan view of the hull flaps allowing rearward movement of the ship; . Figure 7 is a longitudinal sectional view of a ship with a conduit joining the front to the rear of the ship; . Figure 8, like Figure 9, is a longitudinal sectional view of two submarines with their conduit formed by a double jacket and the walls of the submarine. Figure 1 is a plan view of two heat engines (2ι) and (22). Note that the motor (22) has been rotated 180 ° in order to rotate the motor (2ι) which drives the propeller (5) through the shaft (3); the motor (22) drives the propeller (6) through the shaft (4). There have been pinions (34,35,36,37) to transmit the movement of the motors to the propeller shafts; we could take any other means such as belt, chain (etc.). This arrangement has the advantage of canceling the torques of the two motors at equal speed and since the counter-rotating propellers have no reaction torque, the assembly has no resulting torque and the vessel or the submarine does not undergo any torque.

Figure 2 is a longitudinal sectional view of the ship or submarine equipped with these counter-rotating propellers. Note the vessel (1) which is equipped with a cam engine (2) driving two concentric motor shafts (3) and (4), rotating at the same speed but in opposite directions, the motor shaft (3) driving the propeller (5) and the shaft (4) driving the propeller (6). Of course, the propellers (4) and (5) have an inverted pitch to obtain the displacement of the ship. The efficiency of the counter-rotating propellers improves the thrust and therefore the propulsion.

Figures 3 to 9 illustrate different embodiments and use of a propulsion assembly of the aforementioned type produced in accordance with the invention.

Figure 3 is a longitudinal sectional view of the ship or submarine equipped with two counter-rotating propellers rotating inside a cylindrical hull secured to the ship. We find Figure 2 but a hull (7) integral with the ship (1) surrounds the two propellers (5) and (6), the outlet walls (8) of the hull (7) constituting a reverse gear (well known in aviation), shutting off the water outlet pushed by the propellers and opening in corolla on a part of the rear cylinder to let the water pass.

Figure 4 is a perspective view of the cylindrical hull (7) at the height of the counter-rotating propellers and square or rectangle output so as to constitute either a means of lateral movement of the ship, or a reverser. We find the same characteristics as Figure 2, but the water outlet of the hull is a square or a rectangle, characterized in that the upper (9) and lower (10) horizontal sides are fixed, integral with the hull ( 7) while the vertical sides (11) and (12) are movable around the vertical axes (13) and (14). We will see how these flaps controlled by the pilot of the ship, will make it possible to obtain either a lateral displacement, a reverser, or even a rudder by modifying the direction of the water outlet pushed by the propellers.

Figure 5 is a plan view of an embodiment of the hull (7) shown in the case where the pilot wants to perform a lateral movement. The ship (1) is provided with a hull (7) secured to the boat by tie rods (15) and (16), a cylindrical part (17) of the hull surrounds the two counter-rotating propellers (5) and (6 ), it ends with a square or rectangle part (18), the upper (9) and lower (10) sides are fixed and integral with the hull, the vertical sides (11) and (12) pivoting around vertical axes (13) and (14) fixed on the horizontal fixed sides. The pilot acted on the jack (19) which is connected by an arm (21) to the vertical pivoting side (12) which closes the water outlet (23) but opens an outlet (24) perpendicular to the outlet (23) . The ship therefore moves laterally. Figure 6 is a plan view of the hull flaps allowing rearward movement of the ship or submarine. We find all the elements of Figure 5, but in this case, the pilot acts on the two cylinders (19) and (20) to close the water outlet (23) and clear the openings (24) and (25) . The water reverses its direction and the ship or submarine goes in reverse. The pivoting flaps (11) and (12) can serve as a rudder when the pilot acts on the jacks (19) or (20) by modifying the direction of the thrust of the propellers (5) and (6), by the displacement of a single component. It follows a great simplification and an improvement facilitating the piloting.

Figure 7 is a longitudinal sectional view of a ship with a conduit joining the front to the rear of a ship (1). A conduit (26), of large diameter to accommodate the two counter-rotating propellers (5,6), leaves from the front (27) to the rear (28) of the ship (1) or of the marine. The front (27) and the rear (28) are arranged in the form of a funnel so that the water flow formed by the advancement of the ship or submarine is absorbed by the water flow contra-rotating propellers, so as not to cause eddies. The motor or motors (2) which drive the propellers are placed parallel to the duct, they take the motor shafts (3) and (4) integral with the propellers (5) and (6) by four bevel gears (29,30,31 , 32), the motor shaft (4) drives the pinion (29), the motor shaft (3) drives the pinion (30), the pinions (29) and (30) drive the pinions (31) and (32 ) integral with the propellers (5) and (6). The ship or submarine will therefore have the same dimensions at the front, center and rear, it will not cause any eddies, which will improve propulsion.

FIG. 8 is a view in longitudinal and vertical section of the submarine (1) with a double envelope (33) surrounding the walls of the submarine. We find the same references as before. The motors (2) drive the propellers (5) and (6), the upper sides (9) and lower (10) form the hull, the movable flap (11) pivots around the axis (13). This envelope (33) may be made of vibration absorbing materials and, as the water flow resulting from the advancement of the submarine is absorbed by the two counter-rotating propellers, there is the absence of turbulence created by the advancement of the submarine, there will therefore be very few vibrations that can be picked up by devices for detecting the presence of submarines.

In the case of Figure 8, the water is sucked in front by the depression created by the operation of the counter-rotating propellers.

FIG. 9 is in accordance with FIG. 8, except that the counter-rotating propellers (5) and (6) are located at the front of the submarine and discharge the water pushed by these propellers at the rear. We find the same notations.

Of course, other solutions for moving reversing flaps can be produced, without thereby departing from the scope of the invention.

It is the same for the shape and location of the conduits which absorb the water flow resulting from the advancement of the ship or a submarine.

Motor shafts turning in the opposite direction could be obtained with one engine turning to the right and another turning to the left instead of reversing one engine with respect to the other engine. We could add to Figure 1 a planetary gear system so as to force the heat engines (2ι) and (22) to rotate at the same speed but in reverse, without departing from the scope of the invention.

One could also put in the conduit only a single propeller followed or not by a deflector, without thereby departing from the scope of the invention of the conduit which would be opposable.

One could also produce other forms of reversing flaps (11) and (12) by improving the lateral outlets of the water pushed by the propellers, without thereby departing from the scope of the invention.

Claims

1 / Ship propulsion device (1), comprising two concentric and counter-rotating propellers (5,6), rotating at the same speed but in opposite directions, with reversed steps, said propellers (5,6) being driven by two drive shafts (3,4), either from two heat engines (2ι, 22), one of which rotates in opposite directions to the other, each driving a drive shaft, or from a cam engine (2) comprising two concentric motor shafts (3,4), rotating at the same speed but in the opposite direction, such a drive making it possible to suppress any reaction torque of the ship (1) around the axis of the propellers (5,6), the torques of rotation of the propellers (5,6) being zero as well as those of one or both engines, characterized in that the concentric and counter-rotating propellers (5,6) are placed inside a cylindrical hull making it possible to avoid the cavitation and the formation of vortices generated by each propeller, and which is arranged in such a way n that the outlet walls of this hull (7) constitute a thrust reverser by closing the water outlet and opening in half or as a corolla to reverse the direction of water flow and constitute the reverse gear . 2 / Device according to claim 1, characterized in that the hull (7) which envelops the two counter-rotating propellers (5,6) is cylindrical at the height of the two propellers, then becomes square or rectangle, so that the upper and lower horizontal sides are fixed, integral with the hull (7), and that the right and left vertical sides are movable around a vertical axis, resting on the horizontal sides so that the pilot can, according to its order, transform this hull either into a reverser, or into a means of lateral displacement of the ship, or into a rudder by changing the angle of the exit of the hull. 3 / Device according to one of claims 1 and 2, characterized in that the two concentric and counter-rotating propellers (5,6) are placed inside a conduit (26) connecting the front to the aft of the ship or submarine, and to improve propulsion. 4 / Device according to claim 3, characterized in that the inlet (27) and the outlet (28) of the conduit (26) are flared so that said conduit substantially adsorbs the volume of water generated by the movement of the ship or submarine (1), in order to avoid all advancement vortices, the bow, center and stern of said ship or submarine having substantially the same dimensions. 5 / Device according to one of claims 3 and 4, characterized in that the ship (1) is a submarine and that the propellers (5,6) placed at the front or rear of said submarine entrain a volume of water which passes through a conduit formed by the hull of the submarine and an outer envelope (33) of vibration-absorbing material, surrounding the submarine, the volume of water being either sucked if the propellers are, at the rear, either compressed if the propellers are placed at the front of said submarine. 6 / Vessel (1) equipped with a propulsion device with propellers (5,6) concentric and counter-rotating according to one of claims 1 to 5. 7 / vessel (1) according to claim 6, characterized in that it comprises a conduit (26) for water passage connecting the front to the rear of said vessel.