MECHANICAL FLUID DYNAMIC DEVICE FOR THE PROPULSION AND FLOW CONTROL IN THE WATER-JET PROPELLED BOATS

The subject of this invention is an integrated mechanical fluid dynamic device or unit to be coupled to a traditional boat water-jet, able to interact with the some jet and to modify all the characteristics of the said hydraulic flow, obtaining a water-jet controlled and adjusted in thrust and direction, with advantage to the best speed and consumption performances.

Currently and usually the water-jet propulsion units are not able or are not intended to control and adjust the parameters of the flow which determines the thrust, in fact, they are suitable only to convey the fluid and give the flow a single direction, according to the amount of pumped water, furthermore all the traditional water-jets utilise the pumping system with underwater release of the hydraulic flow under the surface of the water.

The propulsion unit, subject of this invention, unlike those of the known technique, allows essentially to adjust and control the characteristics of the flow and the pumped water jet, like density, speed, angle of incidence, direction, while in the traditional water-jets nothing of that happens, in fact they convey and eject the pumped water without any control.

As far as the applicant knows in fact up to today the devices of the known technique do not allow the adjustment of the characteristics and the direction of the jet.

On the contrary the subject of this invention, by the adoption of the device as described and depicted in the following, allows through a variable volume directional chamber to increase the jet speed besides its angle of incidence, while the density is changed by the introduction of gas, for example the exhaust of the engine, into the same chamber, finally the kinetic energy of the jet is increased by the jet ejection above the surface of the water, with an adjustable slant which characterises the boat attitude.

That is the main difference from the methods of the known technique, the subject device or unit bringing instead a considerable increase of the performance, both about speed and agility / handling.

In fact the jet, besides the fact that it can be released underwater like the traditional water-jets, can be also released outside the water above the water surface, such an option resulting more efficient and more valuable in terms of better performances.

Furthermore, interacting through the nozzles by the injection of engine exhaust or compressed air and adjusting the volume of the flow, it can be obtained the variation of the main characteristics of the jet like speed and density, and then

also power and angle of incidence, by the increase of the kinetic energy of the jet itself, leading to a cleaner wake, an attitude always under control and a more effective handling in the movement of the boat.

In any case the jet results already by itself exceptional and efficient, also without the injection of gas or compressed air, because of the variation of its flow and direction.

The subject of this invention is a mechanical fluid dynamic device or unit, to be applied also to a traditional boat water-jet, able to interact and transform all the characteristics of the said hydraulic fluid into a modified controllable and adjustable water-jet, to full advantage of better speed and consumption performances. Currently and usually the water-jet propulsion units are not able or are not intended to control and adjust the parameters of the flow which determines the thrust, in fact, they are suitable only to convey the fluid and give the flow a single direction, according to the amount of pumped water, furthermore all the traditional water-jets utilise the pumping system with underwater release of the hydraulic flow under the surface of the water.

More in detail, unlike the devices of the known technique, the present invention refers precisely to:

A mechanical fluid dynamic jet device for the propulsion and control of the hydrodynamic flow in the water-jet propelled boats, characterised by the fact

that it includes conveying ducts of the fluid, a tubular mean with variable geometry and variable internal volumes, a body centred inside said tubular mean, an adjustable nozzle to eject the fluid, one or more gas injectors, and means to change the jet direction.

The said mechanical fluid dynamic jet device for the propulsion and control of the hydrodynamic flow in the water-jet propelled boats is furthermore characterised by the fact that the variation of volume of the internal chamber of the tubular mean for the flow control is obtained by displacement of the adjustable nozzle.

In addition the device of the invention is characterised by the fact that it has a tapered onion-shaped body to drive and regularise the flow inside the chamber and by the fact that it is centred and fixed inside the said tubular mean by means of a ring or clamp carrying the onion-shaped body with spokes or fluid dynamic blades.

Furthermore the movement of the nozzle for the adjustment of the volume of the chamber inside the tubular mean is carried out by a motorised system including an electrical stepper motor and by a gearbox, pinion and cogwheel, suitable to displace and adjust said nozzle from a minimum to a maximum opening position for the variation of the kinetic energy of the jet itself.

While the gas injection is carried out by means of injectors communicating with the interior of the tubular mean, in order to change the main characteristics of the jet, like speed and density, besides the performances, power and angle of incidence, of said jet together with the adjustment of the volume of the chamber, with the consequential variation of the kinetic energy of the jet itself, said gas could be composed by the exhaust extracted from the engine or by a compressed air coming from a tank with release and control valve, connected to a turbocharger, driven by the same engine of the boat.

The device of the invention allows in addition the variation of the direction and the slant of the jet, course and attitude of the boat, through means formed by a jointed system, suitable to orient said tubular body mounted on said joint in direction and slant, which allows the displacement of the device in all the directions.

By means of this device the jet, besides the possibility of a release underwater like the traditional water-jet, can be also released outside the water above the water surface, like a jet engine or water-jet, said option resulting more effective and more appreciable in terms of better performances. Particularly the response at low speeds must be noted, while by the traditional water-jets at low speeds, that is when the boat is not yet about to plane, the engine consumes as much as at high speeds, this defect, which remains still a handicap in the traditional boats, is instead remarkably solved by this invention.

In addition said device, besides the installation "ex novo" on the boats or craft intended for the water-jet propulsion, allows retrofit actions on the boats of the known technique, because it can be easily installed also on the boats which have a traditional water-jet.

We give now in the following a description of a particular non-limiting form of carrying out of the invention without depriving of anything the generality of the invention itself and without limiting the field of implementation, with reference to the explanatory drawings of the attached tables.

Figure 1 shows a view of the device as applied to a water-jet propelled boat. Figure 2 shows a view more in detail of the table 1 indicating also the flows and the movements of the device. Figure 3 shows a cross section of the body and the tubular chamber, the nozzle and the joint of the device of the invention.

A motor or pump 4 through the intake 3, 25 of a boat 5, 11 takes and conveys the fluid in the duct 2 and in the subsequent duct 9 up to the inside 1' of the tubular chamber 1, where the flow is managed, controlled and adjusted and subsequently ejected and transformed in jet 6 through the nozzle 16, preferably above the water surface 10 (Figures 1 and 2).

The flexible or rigid ducts 2, 9, can be made of any material compliant to the requirement of watertight and mechanical resistance, suitable to connect the pump 25, 3 to the control and propulsion device 21, 8, 1, 16 (Fig. 2). The pumped fluid can be altered as one likes in its characteristics by the concomitant introduction of gas taken from the engine exhaust 4 through the duct 2a or alternatively from a compressed air tank and injected through the control valve 26 by means of one or more injectors 21 into the duct 2 (Fig. 2) in a preferred form of manufacture of this invention, or into the chamber 1' of the tubular body 1 (Fig. 3) in a second preferred form of manufacture. Said fluid comes into the internal chamber 1 ¹ of the tubular body 1, driven and regularised by a tapered onion-shaped body 17 intended to regularise the flow, centred inside said chamber 1' by means of a ring or clamp 18 carrying the onion-shaped body with fluid dynamic blades and ledges 19, 20 (Fig. 1). Similarly a nozzle 16, actuated and adjusted from a minimum to a maximum opening position by means of a cogwheel 15 and a pinion 13, driven by an electrical stepper motor 12, 24, 14, allows the variation of the internal volume 1" of the tubular chamber 1 (Fig. 1).

Said device works like a hydro-jet, including a tubular body 1 , with an internal variable geometry and volume chamber 1', a tapered onion-shaped element 17, fixed 23, 19, 20 and maintained centred inside the tubular body by a clamp with fluid dynamic spoke 18, an outlet nozzle adjustable in position and opening 16, a motorised system 12, 14, 24 (e.g. an electrical stepper motor) suitable to allow the displacement and the adjustment of said outlet nozzle 16 by means of

the pinion 13 and the cogwheel 15, a system with cables or levers or pistons or telescopic arms (here not shown in the Figures) suitable to orient the direction and the slant of the device by means of the guide of the tubular chamber 1, 1' mounted on the joint 22, 8, then of the jet 6, to drive the changes of course and attitude of the boat (Fig. 3).

The jet 6 of the pumped 3 and conveyed 2, 9, 1' fluid is in this way controlled by the device of the invention which allows to change its characteristics of speed and density as one likes, to alter the fluid with the injection of another fluid into the duct 2 or into the chamber 1', that precede the mobile nozzle 16 which releases said jet, suitable to change the flow characteristics and to allow the mix of the fluid with a gas, which in this case is the exhaust of the internal combustion engine which drives the pump 4, or alternatively compressed air, and finally the undoubted innovation which breaks definitely with tradition, the fact that the substantially elaborated flow is ejected above the water surface 10 with slant and direction controlled and adjusted as one likes 8. To come to the point this invention can replace or succeed all the traditional water-jets for boat propulsion, because it allows for the first time to change the jet characteristics, to alter the flow, to obtain more effectiveness in the propulsion, to obtain considerable increase of speed for the same used power.

Interacting through the nozzles injecting the engine exhaust or compressed air and adjusting the geometry of the chamber 1' by means of the electrical stepper

motor 12, 13, it results not only the variation of the main characteristics of the jet 6 like speed and density, but also power and angle of incidence, with increase of the kinetic energy of the jet itself.

The device subject of this invention ensures the boat besides the best performances already mentioned, a neutral progress of the movement always in horizontal position, more comfort, more angle of incidence by the changes of direction, saving of power, saving of fuel, all advantages that of course were up to now not found in the previous state of the technique because in the traditional water-jet it is not possible to intervene neither to control nor to alter the hydraulic jet. All these things are on the contrary achievable by the device subject of this invention. The subject of the invention conceived and tested by the applicant at first sight characterises itself mainly because the jet 6 happens above the water surface 10 few centimetres above the water-line 10 of the boat 5, 11, and precisely it happens from the top downwards in diagonal with an adjustable slant 8 at will. Further analysing the achieved results we can mention the fact that utilising this device the wake of the boat is cleaner and the turbulent foamy part is no longer tied to the stern but it is at a distance of a few metres, in fact, by the implementation of the invention it is possible to noticeably improve also the fluid dynamics of the boat. Many further advantages and improvements can be achieved by the use of the invention; the device can be carried out of any metal or plastic or composite provided that it is suitable and complies with the technical mechanic requirements peculiar to the intended use.

The water-jet control device described above is finally characterised by the fact that by means of it, veers more precise, cleaner und sharper can be achieved with less wasted power; in fact by the traditional water-jets to do a veer the rudder damp the jet 6 taking power and incisiveness from the jet itself, inducing a noticeable loss of speed, while by the device, subject of this invention, the veer is always carried out with the full jet 6 available, without the need of an additional rudder and without damping, without taking or wasting power and incisiveness, simply because the jet is not diverted by other members, but it is oriented by the joint 8 by means of dedicated telescopic arms (here not shown in the tables), that allow the displacement in all the direction of the tubular body 1 of the device, in fact thanks to this the jet can be fully directed without being damped (Fig.3).

The device subject of this invention can have many forms and variations relevant to the geometry, the fluid dynamics, the materials, the details or particulars here not described but not for this excluded by the ambit of protection of such invention.

It finds particular use by the propulsion and control of the hydrodynamic flow in the water-jet propelled boats or craft.

Furthermore said device allows retrofit actions in the boats of the known technique, because can be easily embodied also on the boats that have a traditional water-jet.