Sea and ocean wave energy converter

A device for converting the energy of sea and ocean waves, including a turbogenerator connected by means of pipelines to input and output elements on which there are mounted ballast systems and stabilizers. The input and output elements are designed as a high pressure vessel and a low pressure vessel, respectively, each having a gas cushion. A high pressure compressor unit and a low pressure compressor unit are, respectively, mounted on these vessels and are connected to high pressure and low pressure gas tanks, respectively, and to the respective gas cushions. The converter is connected at at least two different points to the sea bottom by means of at least two flexible cords the length of at least one of which may be altered.

This invention relates to the conversion of the energy of sea and ocean 
waves into electric power. 
There is well known a device for the conversion of the energy of the 
gravitational waves, i.e. sea and ocean wind-formed waves, or dead or 
ground sea swell in which a series of input parallel converters are 
connected by means of an input collector manifold with a turbogenerator 
which on its turn is connected by means of an output collector-manifold to 
a series of parallel output converters which let out the water in the low 
part of the wave. In such devices, the input and output converters have 
independent sources of gas under pressure. 
The device is maintained at a given level by means of a ballast system 
fitted to the converters and stabilizers. 
The disadvantage of this device is the large number of input and output 
elements which makes this device very complicated. Furthermore, the flow 
should surmount the local resistances in its inflow in the input and 
outflow from the output collector or manifold as a result of which there 
occurs a decrease in the harnessed energy. 
Another shortcoming of such a known device is that the independent sources 
of gas under pressure maintain the water in the input and output 
converters and this can vary over a wide range. When the level is very 
low, part of the gas can flow out of the converters and this results in a 
loss of part of the compressed air. Conversely, when we have a high level 
and a little volume of the gas cushion, the latter is inferior in its role 
as buffer and energy accumulator. 
Furthermore, this device cannot be directed at a specified angle towards 
the wave front, and in this way an important reserve for increasing its 
smoothness of operation and improving its efficiency cannot be utilized. 
It is among the objects of the present invention to eliminate the 
shortcomings of the prior device discussed above, by providing a device 
for converting sea and ocean wave power to electric power with improved 
efficiency, better stability with respect to the waves, and considerably 
better smoothness and regularity of the flow of water running through the 
turbine. 
This problem has been solved by replacing the system of input converters 
and the input collector manifold by a high pressure vessel the length of 
which is at least equal to the length of the wave and the width of which 
is in the range of the length of the active part of the wave. 
Analogically, the system of output converters and the output collector 
manifold have been replaced by a low pressure vessel. The high pressure 
and the low pressure vessels are connected by means of pipelines to the 
turbogenerator group which converts the energy of the water flow to 
electricity. In its low part, the high pressure vessel has controls for 
admitting the water, an input guiding device in the form of blades 
connected to the high pressure vessel and disposed in it, the blades being 
inclined towards the turbine. In its lower part, the low pressure vessel 
has two systems of controls for discharging the water, these controls 
being located in such a way as to direct the water in two flows of 
opposite direction, perpendicular to the longitudinal axis of the low 
pressure vessel, and a guiding device associated with the low pressure 
vessel in the form of two rows of blades fitted outside the low pressure 
vessel and attached to it. Each row of blades of the guiding device of the 
low pressure vessel is symmetrical with the other row of blades, the 
symmetry being with respect to a vertical plane crossing the longitudinal 
axis of the low pressure vessel. A high pressure gas cushion is 
established in the high pressure vessel, the average pressure and mean 
volume of which can be regulated. In addition, the high pressure vessel is 
fixed to a high pressure gas tank which is connected to the high pressure 
gas cushion by means of a high pressure compressor unit including a 
compressor and a system of valves. The high pressure compressor unit is 
connected to the high pressure vessel and is designed to transfer the gas 
in both directions; it can also connect the high pressure gas cushion to 
the atmosphere. 
The low pressure vessel forms a low pressure gas cushion whose mean 
pressure and mean volume can be regulated. A low pressure gas tank is 
connected to the low pressure vessel, and the tank is connected to the low 
pressure gas cushion of the low pressure vessel by means of a low pressure 
compressor unit to divert gas in both directions, such unit consisting of 
a compressor and a system of valves. The low pressure compressor unit 
permits the transfer of the gas from the low pressure gas cushion to the 
low pressure gas tank, and vice-versa; it can also connect the low 
pressure gas cushion to the atmosphere. 
A high pressure, or a low pressure ballast system, is fixed to the high 
pressure vessel or to the low pressure vessel, respectively, the ballast 
system serving to control the specified depth of submergence of the 
device. 
A high pressure oscillation compensating or a low pressure system is 
mounted to the high pressure, or low pressure, respectively, system to 
compensate vertical oscillations and those around the longitudinal axis. 
The high pressure, low pressure, respectively, vessels are made in one or 
more sections which are interconnected by hinge devices operating along a 
horizontal axis, perpendicular to the longitudinal axis. Sealing between 
the individual sections is provided by flexible sleeve couplings. If the 
respective vessels have more than one section, the tanks, the ballast and 
compensation systems are also made in sections. 
The sea and ocean wave converter is attached to the sea bottom at least in 
two different places along the length of the converter by means of 
flexible cords, and the length of at least of one of the flexible cords 
may be altered in such way as to form a specific angle between the 
longitudinal axis of the device and the wave crest. This alteration is 
made by means of a winch. 
The sea and ocean wave converter is supplied with an automatic control 
system made up of automatic control units for the mean pressure of the gas 
cushion, units for the automatic control of the ballast system, a unit for 
the control of the turbogenerator unit, and a unit for controlling the 
angle between the device longitudinal axis and the direction of the wave 
crest. The individual control units are contained in a common control 
unit. 
The turbogenerator unit is submerged to a sufficient depth in order to 
reduce the cavitation effect. 
It is an advantage of this device that it is compact, so that the energy of 
water flow can be utilized to a maximum. Another advantage is that the gas 
tank to which the gas cushions are connected stabilize the water level in 
the high, or respectively the low pressure vessel. Furthermore, due to the 
improved disposition of the direction of the converter to the wave crest 
and the greater smoothness of the operating water flow, the capacity of 
the converter is improved and it has a higher efficiency.

The high pressure vessel 1 is a closed circuit vessel whose length is at 
least equal to the length of the waves, and whose width is in the range of 
the active part of the waves. In its lower part vessel 1 has input valves 
9 in the form of flat members which open inwardly at a sharp angle in the 
direction of a turbogenerator 13 and which rotate around axes 12 of the 
input valves 9. The shafts (axes) 12 are perpendicular to the longitudinal 
axis for the high pressure vessel 1. 
An input guiding unit 10 consists of blades which are fixed to the high 
pressure vessel 1 and are fitted in its lower part. Over the high pressure 
vessel 1 there is mounted a high pressure tank 2 and a high pressure 
compressor unit 3 for transferring gas in both directions. The high 
pressure compressor unit 3 for transferring gas in both directions 
consists of a compressor and a system of valves for changing the direction 
of gas flow. The high pressure compressor unit 3 may also serve as a 
two-way connection between the atmosphere and a high pressure gas cushion 
4 occupying the upper part of pressure vessel 1. The high pressure 
compressor unit 3 for transferring gas in both directions is connected to 
the high pressure gas cushion 4 by means of high pressure connecting 
pipelines 18 and 19. 
A low pressure vessel 5 is a closed-circuit vessel having a width in the 
range of the active part of the waves. Vessel 5 has in its lower part two 
systems of output valves 15 which open outwardly at an acute angle towards 
the vertical longitudinal plane of the low pressure vessel 5. The shafts 
17 of the output valves 15 are parallel to the longitudinal axis of the 
low pressure vessel 5. The output guiding unit 16 has the shape of blades 
which are fitted outside the low pressure vessel 5 and symmetrically 
towards its vertical longitudinal plane, and are fixed to vessel 5. A low 
pressure gas tank 7 is connected by means of a low pressure gas pipeline 
21 to a low pressure compressor unit 6 is connected to a low pressure gas 
cushion 8 which occupies the upper part of the low pressure vessel 5. The 
low pressure compressor unit 6 can also provide a two-way link between the 
atmosphere and the low pressure gas cushion 8. 
The turbogenerator unit 13 is disposed at a sufficient depth under the 
level of the high pressure vessel 1 and the low pressure vessel 5, and is 
connected to the high pressure vessel 1 by means of an elastic input 
flexible hose 11 and to the low pressure vessel 5 by a flexible hose 14. 
The high pressure vessel 1 can be made in more than one section connected 
by means of hinges 27 (FIG. 2) with the shafts of the hinges 27 
perpendicular to the longitudinal axis of the high pressure vessel 1, and 
by means of flexible sealing high pressure sleeve couplings 26. 
Analogously, the low pressure vessel 5 can also be made of more than one 
section connected by hinges to the horizontal shafts and flexible sealing 
low pressure sleeve couplings 30. In this case the high pressure gas tanks 
2 are interconnected by flexible high pressure gas pipelines 25, and the 
low pressure gas tanks 7 by flexible low pressure gas pipelines 29. 
Ballast systems 24 connected to flexible pipelines 38 are mounted on each 
section of the high pressure vessel 1. In the same manner, ballast systems 
28 connected to flexible pipelines 31 are mounted to each section of the 
low pressure vessel 5. The ballast systems 24 and 28 are designed to 
achieve the submergence of the high pressure vessel 1 and the low pressure 
vessel 5 respectively, to a specified depth. 
A stabilizer 55 for the vertical oscillations and those around the 
longitudinal axis is mounted to each section of the high pressure vessel 1 
made of support beams 37 of the high pressure vessel 1, a horizontal 
stabilizer 35, and a vertical stabilizer 36. Analogously, to each section 
of the low pressure vessel 5 there is a stabilizer 56 for the vertical 
oscillations and those around the longitudinal axis made of support beams 
41, horizontal stabilizer 39 and vertical stabilizer 40. 
The oscillation compensation systems are submerged to a sufficient depth 
under the high pressure vessel 1 of the low pressure vessel 5. 
The sea and ocean wave energy converter is fixed in at least two different 
points 23 (in the form of a winch) and 32 along the length of the device 
by means of flexible cord 33 of changing length, and by flexible cord 43 
respectively of constant length for the first point of anchoring 34, and 
second point of anchoring 42 respectively, to the bottom of the sea. The 
point 32 of anchoring may also be in the form of a winch. The length of 
flexible cord 33 can be altered by means of the winches fitted to one or 
both of the vessels 1 and 5. 
As shown in FIG. 3, the sea and ocean wave energy converter is supplied 
with a system for the automatic control of the parameters of the gas 
cushions, the depth of submergence of the converter, the angle between the 
longitudinal axis of the converter and the wave crest, and the performance 
of the turbogenerator unit. The parameters of the high pressure cushion 4, 
or the low pressure gas cushion 8 respectively, are measured by the high 
pressure, or the low pressure, respectively, pressure sensors 44, or 47, 
respectively, for the high pressure cushion 4 and the low pressure gas 
cushion 8, and high pressure, or low pressure, respectively, sensors for 
level (level gauges) 45, and 46 for the water in the high pressure vessel 
1, and the low pressure 5 vessel, respectively. The controls for changing 
the pressure in the high pressure 4 gas cushion, or the low pressure gas 
cushion 8, are respectively the high pressure compressor unit 3 or the low 
pressure compressor unit 6 for transferring gas in both directions. 
The submergence depth of the high pressure vessel 4, or the low pressure 
vessel 5 is measured by at least one high pressure sensor 48, respectively 
low pressure sensor 49 for the depth of submergence of the high pressure 
vessel 1, or low pressure respectively, vessel 5. Two or more sensors 50 
are provided for sea level supply information for the parameters of the 
wave heights. Sensor 51 supplies data for the length of the flexible cord 
33 of changing length. Winch 23 is the control device for changing the 
angle between the longitudinal axis of the sea and ocean wave energy 
converter and the wave crest. The performance of the turbogenerator unit 
13 is changed by controls 52 of the turbine and the controls 53 of the 
generator. The data from all of the sensors given above is sent by cables 
to a control unit 54. The signals from the control unit 54 are sent 
through their respective cables to all the controls given above. 
The operation of the Converter, in accordance with this invention, is as 
follows: 
When the wave crest is above a certain sector of the high pressure vessel 
1, the water enters through the input valves 9 into the high pressure 
vessel 1 which in its top part has the high pressure cushion 4 where a 
flow is created which is converted into electric power by means of 
turbogenerator 13. The flow through the output valves 15 of the low 
pressure vessel 5, which has the low pressure cushion 8 in its upper part, 
is discharged in the low part of the wave. The main function of the gas 
cushions is to open and close the valves at the required moment. Thus when 
the wave crest is above a given section of the high pressure vessel 1, the 
hydrostatic pressure in the lower part of vessel 1 is larger than the 
pressure in the high pressure gas cushion 4. For this reason the input 
valves 9 open. Conversely, in sections of the high pressure vessel 1 which 
are in the lower part of the wave, the hydrostatic pressure which acts on 
the input valves 9 from outside is smaller than the internal pressure and 
valves 9 remain closed. Analogically we can explain the effect of the low 
pressure gas cushion 8. The second function of the gas cushions is to 
accumulate and discharge energy. The converter is oriented towards the 
wave crest at a sharp angle by means of winch 23. 
The optimum depth of submergence of the high pressure vessel 1 and the low 
pressure vessel 5 is established either by the ballast systems 24, or 28, 
respectively, or if there are no ballast systems, by means of flexible 
cords 33 of changing length of which, in this case, there should be more 
than one. 
In case of very rough seas, the converter still continues operation by 
submerging to a depth at which the destructive effect of the hurricane 
waves is sufficiently reduced. 
In case that a series of waves of small amplitude which exercise less 
hydrostatic pressure enter the converter, the water level in the high 
pressure vessel 1 drops. In this moment the high pressure compressor unit 
3 transfers part of the gas to the high pressure gas tank 2. In this way 
the danger of discharging gas from the high pressure vessel 1 is 
eliminated. When larger amplitude waves are encountered, the high pressure 
compressor unit supplies gas to the high pressure vessel 1 and obstructs 
the undesirable reduction of the volume of the high pressure gas cushion 
4. The low compressor unit 6 operates in a similar manner. 
Although the invention is illustrated and described with reference to one 
preferred embodiment thereof, it is to be expressly understood that it is 
in no way limited to the disclosure of such a preferred embodiment, but is 
capable of numerous modifications within the scope of the appended claims.