| WO2004067951A1 | 2004-08-12 |
| JPS55112876A | 1980-09-01 |
Patent claims:
1. Method for converting the kinetic energy contained by the flowing water into pressure energy and for using this pressure energy for the production of power. known by the fact that the flow is stopped with a funnel-shaped, or essentially levelled, pressure collecting element, having a pressure relief hole, the diameter area of which is below 15% immediately or indirectly in relation to the front surface of the regulating unit, or the flow-through has been dimensioned so that it reduces the power directed to the device to less than 10%.
2. Method in accordance with patent application 1 known by the fact that a collar-shaped, backwards opening regulating unit, the circumference of which is larger in the flow direction than the circumference of the pressure collector element, has been fastened partly or all over to the outer edge of the pressure collector element.
3. Method in accordance with patent applications 1-2 known by the fact that a turbine, a push piston or another power- producing device has been placed in the pressure relief section of the regulating unit.
4. Method in accordance with patent applications 1 - 3 known by the fact that the power-producing device placed in the throat is not a fixed part of the front funnel but it is structurally such that it may be loosened and fastened without essentially disassembling the front funnel or regulating unit.
5. Method in accordance with patent applications 1 - 4 known by the fact that the power producing device has been dimensioned so that it will achieve its prime effect when the flow- through of the device is below 10% of the flow directed towards the front funnel.
6. Method in accordance with patent applications 1 - 5 known by the fact that the flow-throughs of two or more front funnels have been connected hydraulically and that this conjoined flow-through has been conducted to one or more power-producing devices.
7. Method in accordance with patent applications 1 - 6 known by the fact that the depth of the front funnel from the front surface to the throat is at a maximum of twice the diameter of the front funnel.
8. Method in accordance with patent applications 1 - 7 known by the fact that a backwards opening, funnel-shaped construction, a back funnel, has been placed in the flow-th rough's relief hole behind the power-producing device.
9. Method in accordance with patent applications 1 - 8 known by the fact that a tail-shaped inspector of weights and measures which reaches the space backwards from the throat in the flow direction and that is at least equal to the diameter of the front funnel has been connected to the device unit.
10. Method in accordance with patent applications 1 - 9 known by the fact that the device entity has been fixed to the bottom with a cable, a chain or with another flexible fastening which allows movement.
11. Method in accordance with patent applications 1 - 10 known by the fact that the fastenings of the device unit to the bottom have essentially been made through the front funnel, and/or the device entity turns 180 degrees against the flow with its horizontal axis vertically positioned.
12. Method in accordance with patent applications 1 - 11 known by the fact that underwater pontoons have been fastened to the device unit, the lifting power of which is enough to lift the device onto the surface of the water when floating freely.
13. Method in accordance with patent applications 1 - 12 known by the fact that the pontoons have been fastened to the front funnel or that the pontoons are an essential part of the front funnel.
14. Method in accordance with patent applications 1 - 13 known by the fact that the device entity has been fixed to the bottom with a cable, a chain or with another flexible fastening which allows movement.
15. Method in accordance with patent applications 1 - 14 known by the fact that the device has been essentially anchored to one point on the bottom.
16. Method in accordance with patent applications 1 - 15 known by the fact that the bottom in the anchorage point has been essentially built, "pillowed", so that it may turn around its centre according to the direction of the flow.
17. Method in accordance with patent applications 1 - 16 known by the fact that supporting structures exist inside the front funnel and regulating units have been fastened to them to direct the flow to the throat of the pump and away from the side walls of the funnel.
18. Method in accordance with patent applications 1 - 17 known by the fact that the plate-type flow restrictor, the area of which is essentially at least the size of the flow-through, has been placed behind the equipment in the flow direction.
19. Method in accordance with patent application 18 known by the fact that the flow restrictor is convex or concave in the flow direction.
20. Method in accordance with patent applications 1 - 19 known by the fact that two or more pressure collecting elements have been grouped successively in the flow direction so that the latter pressure collecting element with its regulating equipment has been placed in the turbulence area of the preceding pressure collecting element and/or essentially overlapping with respect to earlier elements.
21. Method in accordance with patent application 20 known by the fact that no power-producing equipment exists in the pressure collecting element in the frontline, in the incoming direction of the flow.
22. Flow power plant equipped with the front funnel known by the fact that it uses the operational method that has been mentioned in patent claims 1-21. |
FLOW PRESSURE POWER PLANT
The object of the invention is to create a method for converting the kinetic energy of flowing water into pressurised energy and the creation of a structural solution in the form of a pump or a turbine, which utilises this pressurised energy.
When power plants that utilise the potential energy created by embanking water flow are left out of the analyses, all other known power plants which receive their driving force from the kinetic energy of water, as well as other power-producing equipment, utilise the kinetic energy of water for this purpose.
In accordance with the method of the invention, the kinetic energy of the flow is converted into pressurised energy. This takes place by stopping the flow with a pressure lifting funnel. The pressure lifting funnel is a steeply convergent funnel of a sizeable area, the throat of which is so small in relation to the frontal area of the funnel that only a small part of the flow may pass through the funnel. Typically, the area of the throat is under 10% of the area of the funnel.
The pressure directed into the funnel is converted into energy with power-producing equipment such as a turbine or a push piston pump which has been dimensioned so that it slows down the flow running through the throat of the funnel, and with that the pressure that builds in relation to the slowing of the flow is recovered with the help of the power-producing equipment's torque increase. Typically, under 10% of the flow directed into the funnel will go through the funnel, whereas the rest passes the funnel by.
Proven Technique
In hydraulics, the basic concepts include the law of the continuity of movement and the Bernoulli equation. The power contained by the flowing liquid consists of three factors which are pressure, speed and fall height, the sum of which is constant.
Bernoulli Equation:
Pi + 1^2 p Vi 2 + p g yi = P2 + 1/2 p V2 ΞΎ + p g y2
Concerning the flow which takes place at the horizontal level the equation can be changed as follows:
Pi + 1/2 p V1 2 = P2 + 1^2 p V2 2
The energy contained by flowing water consists of the energy used to elicit pressure and that used to elicit movement, the total number of which is constant between two points. If the flow rate of water is changed, the pressure will change correspondingly. Therefore, if the flow rate increases, the pressure reduces and vice versa.
Known power-producing equipment which produces power from flowing water is based on the utilisation of the kinetic energy component and on the separating of the kinetic energy from flowing water.
This kind of power-producing equipment takes the form of underwater "windmills", which in principle are similar to wind power plants, but their dimensioning has been adapted to correspond more to the higher density of water than to that of air. "Windmill solutions" have been fixed with small funnels which converge and accelerate the flow.
In all known funnel solutions the total amount of water, or at least the main body of it, is conducted through the throat of the funnel, and the purpose of the funnel is to converge and/or to accelerate the flow.
In those known and steeply convergent funnels, catching splashes is aspired by openness, where the flow-through is small but scattered.
Neither in these underwater solutions, or in ground-based solutions, has the front funnel been used essentially for converging the flow from a wider area towards power-producing equipment such as a rotor or turbine. The obstacles for this have been, on the one hand, the unbearable growth of power directed towards the body of the device, and on the other hand, the fact that the funnel area, which is small in relation to the throat of the funnel, does not produce additional energy.
For example, a funnel area that is two-fold in relation to the throat of the funnel does not produce any essential advantage because
the water flow bouncing from the walls of the funnel to its centre elicits flow disturbance and turbulence in the throat of the funnel, which causes the effect to disappear (Figure 1). In Figure 1 , the front funnel (2), which collects the flow to the front surface of the funnel (3) coming from the left towards the power-producing equipment through the throat of the funnel, has been connected to the power-producing equipment (1).
Because part of the flow directed to the front surface of the funnel is jammed through the funnel, the flow rate increases in relation to the front surface area of the funnel and the throat area of the funnel. The more the funnel converges and the higher the flow rate is, the more steeply the flow that is directed towards the interior walls of the funnel is reflected towards the centre of the funnel.
The present technical levels and technical development areas are taken from the following internet publications, these being two examples: http://www.lunarenerqv.co.uk/technoloqy-duct-full.htm
www.cvberiad.net/librarv/pdf/bk tidal paper15auqO3.pdf
It has been common with these front funnel solutions that they are based on accelerating the flow and the management of the flow mainly through the throat of the funnel. To facilitate this, the funnel has been greatly tapered, in other words it is now mildly convergent. These outlines have not included a front funnel of a significant size but only a small collar version, which has been produced to be very mildly convergent so that disturbing turbulence will not bounce from the walls of the funnel to the centre of the funnel.
In no known utilisation solution for water energy has the production of energy been sought by mainly changing the kinetic energy of flowing water into pressure energy.
The solution of the invention is based on the changing of the kinetic energy of flowing water into pressure energy and on the utilisation of this pressure energy.
This takes place by stopping the flow with funnel-shaped pressure collecting equipment having a small throat in relation to its area. The front surface stops the flow and a conic area of high pressure (item 1 in Figure 3) is formed inside the funnel and to the front surface of the funnel, which converges in the flow direction. The
flow-through of the power producing equipment (item 2 in Figure 3) in the throat of the funnel is dimensioned so that the amount of through-running water will remain under 10% of that directed to the front surface of the funnel.
When the funnel contains high pressure flow and the flow-through rate is essentially restricted to approximately the size of the incoming flow or even smaller, then slow movement with a large torque and strength value will be achieved, and this will be converted into energy by the power-producing equipment.
In accordance with the invention's solution, high pressure is achieved with the help of the oversized front funnel, the walls of the funnel, and the throat of the funnel, which combined produces high thrust levels for the power-producing equipment at the throat of the funnel.
In accordance with the invention's solution, the flow-through is in relation to the power directed to the funnel so that less than 10% of the power flow, which is the square metre of the flow rate multiplied by the area of the throat and is defined as the power directed towards the funnel, is allowed to pass the power- producing equipment.
In accordance with the design of the invention, the method also includes the opening form of the funnel. In contrast to the known funnel outlines, the funnel is constructed in accordance with the steeply convergent method. The purpose of this is to create a vacuum area behind the funnel which reaches behind the power- producing equipment and behind its rear funnel in the flow direction.
This facilitates the evolving of the pressure difference between the front and rear of the power-producing equipment, which is necessary for the production of energy. Whereas the reducing corner is small, and the size of the funnel is also small in funnels of all known power-producing equipment, the area of the funnel in accordance with the invention is at least ten times greater and the reducing corner of the funnel lies at least at 45 degrees in relation to the throat.
In principle, the required pressure may be collected from the flow at the vertical level, in which there is a hole or a very low funnel. In this case, the front funnel becomes very unstable and keeping it in
a vertical position may be difficult. For this purpose, a collar (item 52 in Figure 5) which is loose against the walls of the funnel (item 51 in Figure 5) and is positioned backwards against the direction of flow, may be added at the outer edge of the funnel to increase the stability of the funnel and at the same time also intensify the vacuum behind the funnel created by the bypass flow as it keeps the bypass flow (item 53 in Figure 5) far enough away from the relief hole in the power-producing unit (item 54 in Figure 5).
Power stations that utilise the invention consist of a structurally separate front funnel section and the power-producing equipment unit itself. When the amount of the flow-through is dependent on the power directed into the funnel - in other words dependant both on the speed of the incoming flow and on the area of the funnel - the same effect may be reached at different incoming flow rates by changing the area of the funnel. This, in turn, allows the fact that one power-producing unit is useful at the point of a wide incoming flow area because the power directed into the funnel is made approximately constant by changing the area of the front funnel.
The power plant, in accordance with the design of the invention, may also be built also so that the flow-throughs of several funnels are hydraulically connected to the same circle and this conjoined flow is conducted to the power- producing equipment. This kind of arrangement is especially useful when the incoming flow is small. The connecting may be used to increase the unit effect of the power-producing equipment and to reduce the size variation of the power-producing equipment.
Since high levels of force are directed against the walls of the steeply convergent funnel, the division structures of the flow pressure which receive the part of the pressure directed towards the funnel and which direct the pressure and the flow towards the throat of the funnel (item 6 in Figure 4), may be built inside the funnel.
Another structural solution for the flow pressure plant is the anchorage of the front funnel at the bottom with a cable, a chain or with some other flexible fastening rather than a stiff structure and the equipping of the front funnel with underwater pontoons which keep the funnel at a regulated height from the bottom and away from the circle effect of waves.
The turning of the device against the direction of flow in the variation of the direction of the tidal flow can be managed either so that the device is essentially anchored to the bottom from one section, in which case the flow turns it, or so that the device entity turns around 180 degrees on its horizontal axis positioned vertically in respect to the flow.
With the oversized front funnel, a manifold pressure is exerted on the device as compared to the usual underwater "windmills". The usual supporting structure permanently installed at the bottom will not bear this kind of construction other than in the form of an uneconomically massive structure.
In accordance with the invention, the device has been anchored to the bottom with a cable or with another flexible fastening, and the device's underwater pontoons maintain it at the correct height and in the correct position. With the cable fastening no forces other than the thrust of the flow are exerted on the position of the funnel's supporting structures.
A flow power plant which is in accordance with the invention has been explained in Figure 4.
The device consists of the front funnel (1), the back funnel (3), and the power-producing equipment (2), which may be a turbine, a flow-through pump or some other form of energy-producing equipment with the appropriate power transmission equipment related to it. The front funnel may be an ordinarily funnel-shaped construction or a construction of any shape with a cross-sectional area at the front that is bigger than the cross-sectional area of the throat. The rear funnel (3) has the purpose of increasing the vacuum pressure behind the device and therefore reducing the counter pressure of a rotor or a piston.
The funnel has essentially been anchored to the bottom by fixing it to one fastening point with one or more (4) cables (7), a chain, a bar with joins at both ends or with another fully flexible solution. In the case of the river flow, even more fixing points may exist at the bottom.
To keep the funnel at a fixed distance from the bottom, the pontoons (5) have been fastened to the funnel. To increase the stability of the device, the device's lower fastening may be arranged so that the device is affixed by several cables to the
bottom so that the cables essentially have a shared point at which the lifting powers of the device are directed.
If the diameter of the front funnel is large in relation to its depth, difficulties may emerge in keeping it placed in a vertical direction in relation to the incoming flow. To prevent this, the device may be equipped with a tail which stabilises the device. The effect and efficiency rate of the device are determined by the pressure difference between the incoming side and the relief side. The flow- through meets counter pressure at the back of the device when the water passing around the pressure funnel curves back into the vacuum created behind the funnel (flow arrows 55 in Figure 5).
To prevent this back flow (63), it is possible to construct a flow restrictor (62), as explained in Figure 6, in front of the back funnel (61) and in the flow direction. When the flow restrictor closes off the back funnel from the back flow, the back flow has to circle the edge of the restrictor, and the flow-through of the back funnel avoids contact with this back flow, which reduces the counter pressure met by the flow-through.
Moreover, the invention includes the connecting of more funnels to a flow power plant unit, in which the funnels have been grouped consecutively and are overlapping in relation to each other in the flow direction at the funnel turbulence area. This turbulence area is that area in which the flow rates are unequal due to the effect of the funnel at a point in front of or behind the funnel. The turbulence area ends when the flow rate difference behind the funnel essentially no longer depends on the funnel.
The idea of the arrangement is to utilise the increased flow rate caused by the liquid passing by funnels.
In Figure 7, an account has been given of the power plant unit.
In the figure, two first-line funnels (1) are included in the incoming flow (3). For example, these funnels may be installed at the bottom so that they form a bottom dam with a hole in the middle. When less than 10% of the flow goes through the funnels, nearly the whole flow passes by the funnels (4). If the distance between the funnels is somewhat under half of the width of the funnels, the flow rate doubles in the space between the funnels. When the thrust of the flowing water increases in the cubic meter of the speed, the power directed to the funnel in the second line is increased
eightfold as compared to the power of the incoming flow rate. The funnels may be linked together to whatever number is desired.
This linking has a high significance especially in slow incoming flows. The majority of the energy contained by flowing water is reserved in slow flows in the tide and in rivers. These flows cannot be utilised with modern technology for power production, as is possible by linking funnels.
A solution for reducing building costs is to make the front-line funnels mere pressure disks which have no power-producing equipment. In that case, the task of these pressure disks is merely to increase the speed of the flow directed to the funnels in the next line. In that case, the aforementioned turbulence area starts from these pressure disks.