AU2038599A

AU2038599A - Naval thruster with central motor and two hydraulic jets

Info

Publication number: AU2038599A
Application number: AU20385/99A
Authority: AU
Inventors: Jean-Edmond Chaix
Original assignee: Societe Technique pour lEnergie Atomique Technicatome SA; TechnicAtome SA
Current assignee: Societe Technique pour lEnergie Atomique Technicatome SA
Priority date: 1998-03-17
Filing date: 1999-03-11
Publication date: 1999-09-30
Also published as: FR2776262B1; FR2776262A1

Description

AUSTRALIA

Patents Act 1990 *t *0

U

C 0 a *0*0 0 4 SOCIETE TECHNIQUE POUR L'ENERGIE

ATOMIQUE

TECHNICATOME

ORIGINAL

COMPLETE

SPECIFICATION

STANDARD PATENT 0 0 Invention Title: Naval thruster with central motor and two hydraulic jets The following statement is a full description of this invention including the best method of performing it known to us:i FIELD OF THE INVENTION The invention relates to the motorization of ships by hydraulic jets.

It more particularly applies to a propulsion or thruster unit submerged beneath the ship and which is orientable.

PRIOR ART AND SET PROBLEM In the field of the propulsion of ships, submersibles or nonsubmersibles, it is known to use water or hydraulic jets, commonly 15 known as "hydro-jets". Most of the ships which use such a propulsion type have hydraulic jet thrusters, which are pumping devices within the ship, i.e. within the hull, which consequently has at least one feed line and discharge line for the water and a pump driven by an electric motor by means of a packing gland shaft. Thus, in general 20 terms it is not easy to orient the hydraulic jet or jets in order to modify the propulsion direction. Moreover, numerous ships are frequently equipped with several thrusters of different types, such as bow thrusters, vertical hydraulic engines and main propulsion shafting lines. All these systems are necessary for the handling of such ships.

The object of the invention is to obviate these disadvantages by proposing a new type of propulsion unit making it possible to provide a great manoeuvrability as a result of its use alone and not affecting the hull of the ship with respect-to its shape and functions.

US patent 2 700 343 describes a pumping device whose structure comprises: an electric, discoidal, reciprocating motor having a double electric stator placed between two electric rotors, two groups of centrifugal blades on either side of the motor, at least one fluid discharge volute, ~11~1~ a central shaft and two journals and lateral intakes for drawing in the fluid to be ejected.

SUMMARY OF THE INVENTION To this end, the main object of the invention is a naval thruster having a central motor defining a central axis and supplying two hydraulic jets and which mainly comprises a discoidal, electric motor having two electric rotors and a double electric stator placed between the two electric rotors, two groups of centrifugal blades constituting two hydraulic wheels driven by the motor and placed on either side of I. *the latter and two volutes installed on a central body and in each of which is placed a hydraulic wheel constituted by a group of centri- "fugal blades.

*o With a view to orienting the two jets in all directions defined by a hemisphere, it comprises a central structure constituted by a vertical to handling shaft installed on a central body and perpendicular to the central axis of the thruster for orienting the latter in bearing and 20 the volutes are installed on the central body so as to rotate about the central axis of the thruster, in order to orient the hydraulic jets in pitch, i.e. relative to the horizontal plane. This makes it possible to give the thruster two degrees of freedom, in order to improve the handling possibilities of a ship.

Preferably, the electric motor is of the asynchronous, reciprocating type.

Preferably, the two electric rotors are mounted in rotary manner on two journals fixed to the body of the stator perpendicular to the handling shaft.

The rotary part of the thruster is inter alia constituted, on either side of the central body, by a wheel body mounted in rotary manner on 3 a central ganging shaft and guided in rotation and translation by a bearing and an abutment.

Preferably, the bearings and abutments of the wheels are pad bearings fixed to fixed journals.

In the same way, use is made of pad abutments for the rotary fitting of the two wheels, the pads being fixed to the journals.

In their preferred form, each of the two volutes has a central, lateral intake orifice for drawing in the water to be ejected, the blades of the hydraulic wheels being positioned facing said lateral, intake orifice, i.e. along the rotation axis, the intake orifices being ***perpendicular to the axis of the discharge jets of the thruster.

oooe In this case, said rotation takes place by means of a mechanical bearing, each volute being oriented by the traction on a cable for the .e depth orientation of the jet surrounding the outer surface of the volute. This traction is opposed to the rotary stress naturally pro- 20 duced by the thrust of the jets.

LIST OF DRAWINGS o o• The invention and its different technical characteristics will be better understood from reading the following description with respect to the drawings, wherein show: Fig. 1, in section, the thruster according to the invention.

Fig. 2, in section, a detail of the fitting of a wheel in the thruster according to the invention.

Fig. 3 a side view of the thruster according to the invention.

WMENUMM

4 DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION Fig. 1, in section, shows the main elements constituting the thruster according to the invention.

Firstly, the thruster is suspended on a vertical handling shaft I, fitted in rotary manner on or in the ship, submerged in the water and to the bottom of which is fixed the thruster. More specifically, a central body 2 of the thruster is fixed to said vertical handling shaft 1 and supports the complete thruster. On two journals 30 of the central body 2 are installed the two helical volutes and the electric motor, whose two rotors carry the two hydraulic wheels.

S..

**In the central body, in the centre of the two journals 30, is installed in rotary manner a central ganging shaft 3, which is positioned horizontally and constitutes the rotation axis of the motor and the complete thruster. On each of the lateral portions of the e• central body 2 is located an electric stator 4 of the asynchronous motor. Each electric stator 4 is constituted by a coiled strip, in 20 which are cut notches where the coil is housed. Two electric supply cables 5, passing in the centre of the vertical handling shaft 1 and within the central body 2, supply said two electric stators 4 from the ship.

a The rotary portion of the electric motor is constituted by two electric rotors 6, each facing an electric stator 4. Each of the rotors 6 is consequently discoidal and has a cart wheel structure, whose electromagnetic part is confined in a tight, stainless envelope. Each of the two rotors 6 is integrated in the body of a wheel 7, which is installed in rotary manner on the central ganging shaft 3.

Fig. 2 shows this installation in detail. It is possible to see an electric rotor 6 installed in a mobile bush 17, constituting the main part of the wheel body 7 carrying it. In this embodiment, the 5 electric rotor 6 is constituted by a block of electromagnetic sheets and radial bars 10 in the form of a cart wheel. A short-circuit ring 18 is placed at each end of the bars 10. The assembly is covered by a protective jacket or envelope 11 made from a special steel of the Hastelloy type or more generally of a magnetic, stainless alloy (titanium, Hastelloy, Inconel, etc.).

Each mobile bush 17 of the wheel body 7 is consequently mounted in rotary manner about the journals 30 of the central body 2 on the central ganging shaft 3 by means of a pad bearing and a pad abutment.

Thus, the bearing pads 13 are installed on a bearing support part 14, *which is itself fixed to the journal 30 of the central body 2 of the thruster. The assembly is completed by abutment pads 15 mounted on an abutment support part 16 at the end of each extremity of the central 15 ganging shaft 3. An abutment collet 12, fixed to the mobile bush 17 faces the abutment pads 15, whilst the internal, cylindrical surface of the mobile bush 17 faces the bearing pad 13. A nut 19 locks the wheel body assembly 7 to the central ganging shaft 3. The pads 13 and of the bearing and abutment are mounted on fixed journals 30, con- 20 trary to the conventional procedure. This simplifies manufacture and *limits vibrations.

The central ganging shaft 3 makes it possible to couple the two hydraulic wheels and their integrated rotor, each placed at one end of said central ganging shaft 3. The bearing pads 13 are of the oscillating type. The abutment makes it possible to very precisely define the value of the air gaps of the motor.

With reference to fig. 1, each wheel body 7 carries a group of centrifugal blades 8, each placed in the centre of a helical volute 9.

These two volutes 9 issue into two, not shown, lateral, discharge nozzles. It is possible to see an axial intake 20 in the centre of each volute 9, each facing a group of centrifugal blades 8. Thus, the water sucked axially into each of the volutes 9, by the rotation of 6 each group of centrifugal blades 8, is delivered to the spiral constituted by the volute 9 in order to be ejected from the thruster.

The groups of centrifugal blades are made from a material which is stainless in sea water (titanium, austenic-ferritic steel, marine bronze, etc.).

Fig. 3 better shows the ejection of the water outside the volutes 9, because an outlet 31 has been shown in the upper part of one of the two volutes 9. The water jet discharged in this way is horizontal.

The ship is represented by part of its lower hull 22 in which is *installed in rotary manner the vertical handling shaft 1 shown in fig. 1. The motor supply cables 5 are also shown within the central *shaft 1. The latter is consequently installed in rotary manner by 15 means of two bearings 23 and a thruster orientation mechanism represented by a manipulating lever 24 integral with the vertical handling shaft 1 and accessible from the interior of the ship. Advantageously, said arrangement is completed a rotary connector 25 ensuring the connection to the supply cables Thus, the thruster rotates about a vertical axis when the ship is horizontal, i.e. it is orientable in bearing. Thus, the two hydraulic jets supplied by the thruster are preferably directed in the same direction, the latter being orientable over 360° about the vertical axis. Thus, the thruster can be used for carrying out not only forward and reverse motions, but also bow movements.

The thruster is also orientable in pitch. Thus, as can be seen in fig. 1, the two volutes 9 are fitted so as to rotate about a horizontal axis coinciding with the central ganging shaft 3 with respect to the central body 2. A circular flange 26 is provided in the body 28 of each volute 9 and.is fitted in a circular groove of the lower part 27 of the central body 2. Thus, each volute 9 may or may not rotate independently with respect to the other. It is pointed out that there 7 is no special bearing system, because there is a slow rotation in the water of these two volutes 9 over a maximum course of 1800.

These two volutes are rotated by means of two cables 21, each of which is wound in a groove 29 in the body 28 of each volute 9.

Thus, a traction on the cables 21, in the direction opposite to the reaction direction of the thruster due to the water jets offset with respect to the central axis, can determine the angular position of the thruster about said same central axis. If the traction is higher, there is a thruster rotation in the direction opposite to the reaction rotation due to propulsion. If said traction is slightly lower, the propulsion-induced reaction rotation orients the thruster in the opposite direction. It is therefore possible to orient about a horiz- 15 ontal axis the said thruster as a consequence thereof and also the propulsion direction of the hydraulic jets. Equipped in this way, the thruster can be oriented according to two degrees of freedom, namely two rotations, i.e. all directions perpendicular to the surface e of a hemisphere.

The presently described thruster can have a high power, namely 450 kW, developing a force of 55,000 N, at zero speed.

o ADVANTAGES OF THE INVENTION The thruster according to the invention is an outboard motor, i.e.

located outside the hull of the ship. It is therefore automatically cooled by the water and leads to a gain of volume in the holds of the ship.

The thruster according to the invention has no propulsion shafting line traversing the hull of the ship. This obviates the use of various sealing systems of the packing gland type.

The integration of two electric rotors in the two wheels of the rotary 8 part ensures that there is no addition of losses by fluid friction occurring in the case of a motor submerged in the conventional way.

The main advantage is that the thrust of the thruster is orientable in accordance with a hemisphere, i.e. two degrees of freedom about two rotation axes. Four thrusters according to the invention can replace the conventional, main propulsion lines, the bow thrusters and vertical hydraulic engines. Moreover, they can be combined for stabilizing the ship platform of a floating installation, both under way or when stationary.

The electric motor used is of a conventional nature and does not use a costly or difficultly manipulatable permanent magnet. The fact that it is discoidal makes it possible to reduce losses by fluid friction.

15 The thruster according to the invention can be dismantled when the ship is afloat using two divers.

The opposite, so-called "back to back" installation of the two wheels and two centrifugal blade groups makes it possible to balance the 20 hydraulic and electromagnetic thrusts, so that low capacity, axial abutments can be used.

Claims

3. Thruster according to claim i, characterized in that the two .electric rotors are installed in rotary manner with a central ganging shaft on two journals of the central body and perpendicular to the handling shaft
4. Thruster according to claim 1, characterized in that it comprises at each end of the central ganging shaft a wheel body mounted so as to rotate about two journals of the central body and guided in rotation and translation by means of a bearing and an abut- ment, each of the said wheel bodies carrying an electric rotor Thruster according to claim 4, characterized in that each group of I 10 blades is fixed to the wheel body
6. Thruster according to claim 4, characterized in that the bearings are constituted by bearing pads fitted to the journals of the central body
7. Thruster according to claim 4, characterized in that the abutments are constituted by abutment pads fitted to the journals of the central body
8. Thruster according to claim 1, characterized in that each of the two volutes has a lateral intake orifice for drawing in the water to be ejected, the centrifugal blades being positioned facing said lateral intake orifice i.e. on the central axis of 15 the thruster. 0*
9. Thruster according to claim 1, characterized in that it comprises two cables for orienting the depth of the jet each surrounding the outer surface of a volute for orienting the jet of each of said two volutes with respect to the horizontal axis of the jet by traction on the depth orientation cable and opposing action of water jets passing out of the volutes DATED THIS 11 DAY OF MARCH 1999 25 Societe Technique pour 1' Energie Atomique TECHNICATOME Patent Attorneys for the Applicant:- F.B.RICE CO