WO2006051567A1

WO2006051567A1 - Sea current energy converter

Info

Publication number: WO2006051567A1
Application number: PCT/IT2005/000123
Authority: WO
Inventors: Nicola Giorgio Morrone
Original assignee: Moliseinnovazione Soc. Cons. A.R.L.
Priority date: 2004-11-11
Filing date: 2005-03-07
Publication date: 2006-05-18
Also published as: ITCZ20040019A1

Abstract

Electrical generator driven by the sea stream constituted by a frame carrying on its ends two blade counter-rotating helixes having three or more dovetailed blades with two alternators, almost cylindrical floater, anchorage block, sufficiently heavy to hold the frame and a floater when immersed and subject to the maximum intensity of sea stream, fixed on sea floor, backspring having one wrapped cape placed in the frame and another fixed to the anchorage block, an electrical cable for connecting the alternators to the electrical network.

Description

aKA CURRENT ENERGY CONVERTER

The present invention concerns the electrical generator adopted to be activated by sea streams and the maneuver system which presents the generators helixes axis always parallel to the sea stream direction.

The sea stream in a determined sea zone varies during a day not only by direction, but also by depth related to water surface.

Consequently, a fixed helix generator deprived by the possibility to vary both in direction and depth risks either not to be in axis with the sea stream direction, or to be in the depth different from that of the most effective sea stream.

State of art

To obviate these problems the GB-A-2348250 patent application describes a helix electrical generator mounted on a column. A column must be fixed in a stable mode on the sea floor and the maneuver components are out of water. The helix generator can vary both direction and depth, as it is mounted on a sleeve able to move and rotate round the column. The installation difficulties of this device are considerable, because a hole should be drilled in the sea floor and a column having a height superior to the sea depth should be fixed in the point where the column itself is installed making emerge the command organs.

The GB-A-2348249 patent application describes a helix electrical generator etched to the sea floor through a rigid wrench to anchorage block situated on the sea floor. The generator is substained by a float chamber. By inflating or deflating the chamber it is possible to vary the electrical generator depth. The rigid wrench is mounted on the anchorage block through a hinge in order to be able to rotate and so to vary the generator axis direction. Moreover, to avoid the unbalance determined by the only turbine, the generator type mounting two turbines rotating in the opposite directions

is demonstrated.

This solution type resolves a problem of generator positioning in the axis with the sea stream direction, and to vary the generator positioning depth too. The device being constrained to ruotate to follow the stream must have a sliding contacts device to permit the electrical continuity with a network. The IT-A-CB02A000002 patent application is an analogous solution of generator sea stream direction following problem. In this case a wiping contacts system permitting the electrical connection must be used too.

The principal aim of present invention is to overcome the difficulties present in the state of art.

Invention advantages

The state of art difficulties are overcome by electrical generator driven by the sea stream constituted by a frame carrying on its ends two blade counter-rotating helixes having three o more dovetailed blades with two alternators; almost cylindrical floater; anchorage block, sufficiently heavy to hold the frame and the floater when immersed and subject to the maximum intensity of sea stream, fixed on sea floor; backspring having one wrapped cape placed in the frame and another fixed to the anchorage block; an electrical cable for connecting the alternators to the electrical network, characterized by the fact that the frame is the reticular frame on which two maneuver means are placed for electrical generator alignment with the sea stream. Another characteristics is given by the fact that maneuver means are two rudders. Another characteristics is given by the fact that maneuver means are two maneuver helixes.

Another characteristics is given by the fact that networking structure is formed by circular, square or other form section bars.

Another characteristics is given by the fact that the structure is a folded-plate frame composed by press curved plates having a form that permits to convey the stream towards the two helixes and regulate the stream effectively.

Another characteristics is given by the fact that the floater is composed by one or more cylindrical hulls or of a form such that permits to convey the stream towards the two helixes and regulate the stream effectively.

Another characteristics is given by the fact that the anchorage block is composed by different parts that run one into another and are assembled by a simple contact one with another in the unique block.

Other characteristics and advantages of invention will be clear from the following explanation of some invention realisation modes described in the figures. Short figures description

The figure 1 shows in absonometrical view the frame of generator, object of present inventon.

The figure 2 shows in absonometrical view the frame of generator, object of present invention, on which the puller and alternator stagnum hulls are mounted. The figure 3 shows in absonometrical view the frame of generator, object of present invention, with dovetailed helixes on the alternators.

The figure 4 shows in absonometrical view the frame of generator, object of present invention, with floating modules and maneuver elements. The figure 5 shows in absonometrical view the generator object of present invention fixed to the anchored unit.

The figure 6 shows the anchor unit of generator, object of present invention.

The figure 7 shows the equilibrium static scheme without current.

The figure 8 shows the static scheme with balance moment without current.

The figure 9 shows the static scheme in equilibrium in presence of current.

The figure 10 shows the static scheme with balance moment in presence of current.

Detailed description of invention realisation mode

The sea streams driven electrical generator with a maneuver system will be composed of the following parts: a) a reticular structure frame; b) one or more floating hulls of almost cyindrical form; c) two counter-rotating helixes of three of more dovetail paddles of two alternators symmetrically fixed on reticular structure sides; d) backspring having one wrapped cape placed in the frame and another fixed to the anchorage block; e) the anchor block placed on the sea floor and having the form and weight sufficient to hold the frame with paddles and helixes when it is completely immersed under the water surface and subject to the maximum stream impact; f) an electrical cable for connecting the alternators to the electrical network; g) two maneuver elements (maneuver helixes or ruddles) fixed on the frame in order to avoid the backspring cable self-wrapping and consequently, to avoid the rotating deck with sliding contacts (to maintain the electric connection of electrical cable) around the log block of anchoring and for managing the alignment maneuver of electrical generator in the sea streams direction. Regarding the figures on frame (1) constituted by a reticular structure, there is a floating block fixed in the median position, formed by two or more hulls (2,3) of cylindrical forms or of the forms such to convey the sea stream flow towards the two helixes and to regulate it effectively.

The reticular structure of the frame 1 can be constituted by the bar (4) of any section (circular, square), the structure is a plated frame composed by press curved plates having a form that permits to convey the stream towards the two helixes and regulate the stream effectively.

On the two ends of the frame (1), two counter-rotating helixes (5) having three o more dovetailed blades with two alternators (6) are mounted.

The frame (1) is fixed with a backspring cable (7), having an end roped around a puller (8) fixed in the frame (1) and the other fixed to the anchor block (9), by a hinge (10) that can rotate around the two orthogonal axes.

The anchor block (9) is composed by different parts run one into another and assembled by a simple contact one with another in the unique block. To fix the electrical generator in the desired position the anchor block (9) completed by the hinge (10), to which a backspring cable (7) is connected, is put in the sea, while the other end of the backspring cable (7) is connected to the puller (8). Once in the water, the electrical generator is put to the desired depth making wrap the backspring cable (7) on the puller drum (8).

Afterwards the alternators (6) are connected to the electrical network by the electrical cable (11). By effect of the sea streams variability the electrical generator could be induced to rotate and, consequently, to turn the backspring cable (7) and the electrical cable (11). To avoid this inconvenient two maneuver elements (12) are mounted simmetrically on the frame (1) that serve to carry to the initial position the electrical generator avoiding any torsion of electrical cable (11) as well as utilization of complex systems of sliding contacts charged to be blocked in salted water. Moreover, the electrical generator driven by the sea streams, object of present invention, is capable to self-balance, maintaining a horizontal position both in presence and without a stream. Without a sfream

Considering that all the forces and masses are symmerical in relation to the vertical plane passing by the principal axis, it is possible to compare our machine to a linear structure: a backspring cable is fixed to one end; to the other end the resultant of all structure weights is applied; in an intermediate position (on a higher grade) the floating force is applied. The mutual distances are those of sea generator in relation to the point between the backspring connection point, weight barycenter and floating center; analogously the forces values are those acting to the generator. In reference to the fig. 7 examining the forces moment in relation to the O point (which coincides with the backspring cable connection point) is (the positive moment is clockwise):

M(O) = - d . F_g + l . F_p [ 1 ] where d, 1 are the distances between the point O and floating centre (B) and barycenter (C) respectively. F_g is the floating force and F_p is the weight force. The position will be in equilibrium if M(O) = 0 or

Once the values of Fg and Fp satisfying the equilibrium condition defined in the previous equation are fixed, let us hypothise that our machine has undergone a small α angle rotation on the vertical plane In this case (fig. 8)

M(O) = - (d cos α - e sen α) . F_g + 1 cos α . F_p ; Dividing for cos α we'll have:

M(O)/cos α = - d . F_g + 1 . F_p + e tan α as for [ 2 ]: - d . F_g + l . F_p = O

we have:

M(O)/cos α = + e tan α for 0° < α < 90° we have: cos α >0 tan α>0; so:

M(O)>0

In other words, a couple tending to rotate the structure in hour sense acts to the structure up to carry it into the perfectly horizontal position; this couple is as more important as the floating center has been placed away from the principal axis. The machine would have the same stabilizing behaviour also in the hypothesis of the initial rotation in the negative sense. In presence of stream

In case the machine is immerse in the stationary water stream (v. fig. 9) it is necessary to consider also the horyzontal force S₅ equal to the resultant of the two pushing forces to the helixes summed to the friction force of the frame on the water. Considering that the first two pushing forces (those to the helixes) are absolutely preponderant in relation to structure friction the resultant S is approximately applied to the O-C axis.

In equilibrium conditions (horyzontal position) the resultant S provokes a zero moment in relation to O point. Consequently, the horizontal pushing force value does not influence absolutely on the machine equilibrium.

Differently, such a pushing force becomes important for determining the backspring cabe direction. In fact, for the forces and acting moments equilibrium the backspring

cable must be directed in relation to the θ angle; moreover, the traction T acts on the

same cable.

Also in presence of stream, we consider that the machine ungoes a small rotation by α angle (fig. 10).

In such a hypothesis the S force moment in relation of O point is not equal to zero. Still, it is certainly positive and furtherly balancing.

In other words, the stream contributes, as it was intuitively obvious, to maintain the machine in a horizontal position.

The invention, certainly, is not limited, to the representation of the figures, but can receive perfections and modifications from men skilled in the art, without going out of the patent frames.

Present invention permits numerous advantages and, particularly, allows to overcome the difficulties that could not be superated using the systems that are actually in commerce.

Claims

1. Electrical generator driven by the sea stream constituted by a frame carrying on its ends two blade counter-rotating helixes having three o more dovetailed blades with two alternators, almost cylindrical floater, anchorage block, sufficiently heavy to hold the frame and a floater when immersed and subject to the maximum intensity of sea stream, fixed on sea floor, backspring having one wrapped cape placed in the frame and another fixed to the anchorage block, an electrical cable for connecting the alternators to the electrical network, characterised by the fact that the frame is the reticular frame on which two maneuver means are placed for electrical generator alignment with the sea streams.

2. Electrical generator driven by the sea streams as to the claim 1 characterised by the fact that maneuver means are two rudders.

3. Electrical generator driven by the sea streams as to the claim 1 characterised by the fact that maneuver means are two maneuver helixes.

4. Electrical generator driven by the sea streams as to the claim 1 characterised by the fact that networking structure is formed by circular, square o other form section bars.

5. Electrical generator driven by the sea streams as to the claim 1 characterised by the fact that the structure is a folded-plate frame composed by press curved plates having a form that permits to convey the stream towards the two helixes and regulate the stream effectively.

6. Electrical generator driven by the sea streams as to the claim 1 characterised by the fact that the floater is composed by one or more cylindrical hulls or of a form such that permits to convey the stream towards the two helixes and regulate the stream effectively.

7. Electrical generator driven by the sea streams as to the claim 1 characterised by the fact that the anchorage block is composed by different parts that run one into another and are assembled by a simple contact one with another in the unique block.