Abstract:
A boat for retrieving energy from a flowing stream of water, such as a river or tidal flow, which can be easily moved to a convenient location and which is capable of capturing a significant portion of the energy of the flowing stream. The boat has a bottom and two sides, forming an elongate hull with a bow and a stern at opposite ends, and means for anchoring the boat to hold it stationary in a stream of water. The boat has openable hinged members at the bow and stern to allow water to enter the interior of, and to flow through, the hull from one end to the other. Devices such as paddles are arranged inside the hull for converting energy of the water flowing through the hull into mechanical energy of a rotating shaft.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a method and apparatus for obtaining energy, particularly electrical energy, from a flowing stream such as a river, tidal basin or the like.  
         [0002]     Many types of apparatus have been devised to convert the energy of a flowing stream of water into useable mechanical energy or electricity.  
         [0003]     U.S. Pat. No. 904,892 to Pattosien discloses a “stream power electric float” which may be anchored in a stream so that the water flows beneath it. Two giant paddle wheels, mounted for rotation on the float, are driven by the flowing stream beneath the float. These paddle wheels are coupled by drive belts to an electric generator.  
         [0004]     One advantage of this device is that it may be towed by a tugboat, motor boat or the like to a desired location, adjacent to where electrical power may be needed. A disadvantage is that the flowing stream may easily divert around, and thus bypass the paddles of the water wheels, limiting the amount of power that can be generated.  
         [0005]     The U.S. Pat. No. 3,882,320 to Schmeller discloses a “tide energy conversion device” that comprises a stationary “channel”, rigidly mounted on vertical piles driven into the ocean floor, to capture the ebb and flow of ocean tides. Energy from the flow of water through the channel is converted into mechanical energy by a plurality of paddles or blades arranged on an endless chain stretched between two sprocket wheels. As tide water flows through the channel it pushes the “blades” which move the chain and, in turn, rotate the sprocket wheels. A shaft connected to one set of sprocket wheels drives an electric generator.  
         [0006]     An advantage of this device, over that of Pattosien, is that once water enters the channel, it cannot bypass the blades. However, the width of this channel is somewhat limited and, once fixed in place, the structure cannot be moved from one location to another.  
         [0007]     Various other floating devices for generating electrical power from moving streams of water are disclosed in the U.S. Pat. No. 3,922,012 to Herz; U.S. Pat. No. 3,986,787 to Mouton, Jr. et al.; U.S. Pat. No. 4,104,536 to Gutsfeld and French Patent No. 2,689,184 to Garstka. While these devices have the advantage of being mobile, like the “electric float” of Pattosien, they are unable to convert a significant portion of the energy of a flowing stream into mechanical or electrical energy. This is because the water in the stream can elect to bypass the paddles, turbines or the like which convert the energy from one form to another.  
         [0008]     Further devices for converting the energy of moving water into mechanical and/or electrical energy, are disclosed in the U.S. Pat. Nos. 4,384,212; 4,412,417; 4,443,708; 4,465,941 and 4,717,832. All of these devices are rigid structures, however, and are not designed to be moved from place to place.  
       SUMMARY OF THE INVENTION  
       [0009]     It is a principal object of the present invention to provide a system, including both a method and apparatus, for retrieving energy from a flowing stream of water, such as a river or tidal flow, which can be easily moved to a convenient location and which is capable of capturing a significant portion of the energy of the flowing stream.  
         [0010]     This object, as well as other objects which will become apparent from the discussion that follows, are achieved, in accordance with the present invention, by providing a boat, having a bottom and two sides forming an elongate hull with a bow and a stern at opposite ends; and means for anchoring the boat to hold it stationary in a stream of water. According to the invention, the boat has openable hinged members at the bow and stern to allow water to enter the interior of, and to flow through, the hull from one end to the other (either from bow to stern or from stern to bow). Devices such as paddles, turbines, screws or the like are arranged inside the hull for converting energy of the water flowing through the hull into mechanical energy of a rotating shaft.  
         [0011]     The method according to the present invention comprises the steps of moving the boat to a desired position in the stream of water, anchoring the boat to hold it stationary in the stream, opening the hull at its bow and stern to allow water to flow through it and converting energy of the flowing water into mechanical energy. The boat may be moved to the desired location either by towing it, with a tugboat or the like, or by means of its own source of propulsion, such as one or more outboard motors.  
         [0012]     Preferably, the energy of the flowing water is converted into mechanical energy by means of a plurality of movable paddles which intercept all of the water flowing through the hull. In this way, once water enters the hull, nearly all of its energy can be converted into mechanical energy; that is, the energy of a rotating shaft. By conforming the size and shape of the paddles to that of the hull, water is prevented from diverting around, and bypassing the paddles as it flows through the hull.  
         [0013]     In accordance with a particular, advantageous embodiment of the invention, the bow of the boat includes two upright hinged members, arranged in an inverted V configuration, forming a “prow” when in a closed position. These hinged members are each openable sideways about a substantially vertical hinge line on a leading edge of each side of the hull of the boat. With this arrangement, the hinged members of the bow may be opened into a V configuration, thereby forming a “funnel” to channel the water in the stream through the hull.  
         [0014]     In contrast, the stern may include a single, flat, upright hinged member arranged between the two sides of the hull when in the closed position. This hinged member is openable downward about a substantially horizontal hinge line at a trailing edge of the bottom of the boat to allow water to exit the hull.  
         [0015]     Following its operation in one location, when the boat is to be moved to a new location, the hinged members at the bow of the boat are first closed, preventing new water from entering the hull. The hull is then emptied of water by moving the paddles and causing the water to exit through the stern. Thereafter, the hinged member at the stern is closed and the remaining water in the hull is removed (if desired) by means of a pump. Once emptied of water, the hull may be easily moved.  
         [0016]     For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a perspective view of the mobile apparatus, according to the invention, for retrieving energy from a flowing stream of water.  
         [0018]      FIG. 2  is a top view of the apparatus of  FIG. 1 .  
         [0019]      FIG. 3  is a side view of the apparatus of  FIG. 1 .  
         [0020]      FIGS. 4A-4D  are successive, representational diagrams illustrating the method of operation of the apparatus of  FIGS. 1-3 .  
         [0021]      FIGS. 5A and 5B  are a face view and side view, respectively, of a paddle which is used in the apparatus of  FIGS. 1-3 .  
         [0022]      FIGS. 6A and 6B  are an end view and side view, respectively, of a link in the chain which is used in the apparatus of  FIGS. 1-3 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]     The preferred embodiments of the present invention will now be described with reference to  FIGS. 1-6  of the drawings. Identical elements in the various figures are designated with the same reference numerals.  
         [0024]     The preferred embodiment of the mobile apparatus for retrieving energy from a flowing stream of water is illustrated in  FIGS. 1-3  of the drawings. As is shown there, the apparatus comprises a boat  10  having an elongate hull  12  formed by a flat, horizontal bottom  14  and two upright, flat sides  16  and  16 ′ on starboard and port, respectively. The bow or prow of the boat is formed by two upright flat members  18 ,  18 ′ arranged in an inverted (upside down) V configuration. These members are hinged to the sides of the hull  16 ,  16 ′, respectively, about substantially vertical hinge lines  19 ,  19 ′, respectively. The hinged members  18 ,  18 ′ are sealed together at the prow and sealed to the bottom  14  of the boat when they are in a closed position. During operation, these members may be swung open on their hinges, moved either by hand or automatically using a mechanical or hydraulic mechanism, so that they extend outward from the hull in an open V configuration, as illustrated in  FIG. 2 . In this way, the hinged members  18 ,  18 ′ form a funnel to channel water through the hull.  
         [0025]     Advantageously, the hinged members  18 ,  18 ′ include plates  20 ,  20 ′, respectively, which are extendible, also as shown in  FIG. 2 , to increase the width of the opening of the funnel.  
         [0026]     The stern of the boat is enclosed by a single, flat upright member  22  extending at an approximately 30° angle between the two sides  16 ,  16 ′. This member is openable downward about a substantially horizontal hinge line  23  at the trailing edge of the bottom of the boat.  
         [0027]     When both the front hinged members  18 ,  18 ′ and the rear hinged member  22  are open, water can flow through the channel formed by the sides  16 ,  16 ′ and bottom  14  of the hull. As noted above, the amount of water in this channel may be increased by opening the front hinged members  18 ,  18 ′ into a V configuration and extending the length of these members by means of extension plates  20 ,  20 ′, respectively,  
         [0028]     A significant portion of the energy of the water flowing through the hull channel may be captured and converted into mechanical energy by means of a plurality of paddles which extend downward into the channel. These paddles may be arranged on a single paddle wheel (not shown) arranged at substantially the center of the boat or, as shown in  FIGS. 1 and 3 , they may be mounted on two endless chains  24 ,  24 ′ located just inside the lateral sides of the boat to starboard and port, respectively. The chains are positioned and tensioned by sprocket wheels  26 ,  27 ,  28  on the starboard side, and  26 ′,  27 ′,  28 ′ on the port side, of the boat. Although three sprocket wheels on each side are illustrated, the chains may operate with only two sprockets on each side, or with more than three. The sprocket wheels are mounted for rotation, driving horizontal axle shafts  29 , on upright members  30  attached to the respective sides of the hull. Each of the axle shafts drives a separate electric generator  54  through a suitable mechanical coupling and transmission.  
         [0029]     Paddles  32  are rigidly coupled to individual links  34  of the chains  24 ,  24 ′. These paddles, which are shown in greater detail in  FIGS. 5A and 5B , are preferably formed of front sheet  36 , a rear sheet  38  and an intermediate structure, made of lightweight plastic or the like, so that this relatively large member is light in weight.  
         [0030]     The paddles are preferably substantially spoon shaped with their concave sides facing the incoming flow of water. They are designed and sized to fill the entire cross-sectional area of the channel formed by the hull of the boat. At their outer extremities, the paddles are provided with rollers  42 ,  42 ′ which are received in corresponding grooves in the hull  44 ,  44 ′ as they are moved along from front to back insuring that the paddles, as they move, are constrained to a position transverse to the direction of water flow. The rollers  42 ,  42 ′ are retained in the grooves  44 ,  44 ′ by protruding lips  46 ,  46 ′, respectively. As noted above, the paddles are rigidly attached to links  34  in the chain  24 . A typical link is shown in  FIGS. 6A and 6B .  
         [0031]     The boat may be lowered into, and raised upward in, the water by filling and emptying water tanks or “floating chambers”  48 ,  48 ′ mounted on each side of the hull. Water pumps (not shown) are provided for filling and emptying each tank, similar in operation to that of a submarine.  
         [0032]     The boat may be held in place in a stream of water by means of cables or chains attached to stays on the side of the steam or to a buoy anchored to the bottom of the stream. Preferably, however, especially when the water is relatively shallow, the boat is held stationary by means of vertical rods  50  arranged on each side of the hull which are extendible downward, either by mechanical or hydraulic means, to support the hull from the ground beneath the stream of water. When the boat is to be moved, the rods  50  are raised upward so that their lower-most ends are even with the bottom  14  of the hull.  
         [0033]     Finally, as shown in  FIG. 2 , as the sprockets  26 ,  27 ,  28  and  26 ′,  27 ′,  28 ′ are rotated by the chains  24 ,  24 ′ due to the force of the water that acts on the paddle  32  as the water flows through the hull in the direction shown by the arrows  52 , the sprockets rotate their corresponding shafts  29  which, in turn, act on the corresponding generators  54 . Since the rotational speed of the sprockets and their shaft  29  is relatively low, this speed is increased by an intermediate gear set, such as a planetary transmission, between each shaft and its corresponding generator.  
         [0034]     The operation of the energy conversion system according to the invention will now be described with reference to  FIGS. 4A-4D  of the drawings.  
         [0035]      FIG. 4A  shows a tugboat  60  pulling the mobile apparatus  10  according to the invention upstream in a river  62  having a water flow profile, from one bank to the other, as shown by the arrows  64 .  
         [0036]     After reaching a desired location, which may be next to a town, a bridge construction site, or the like, the apparatus (boat)  10  is caused to descend deeper into the water by filling the side mounted chambers  48 ,  48 ′, as indicated by the darkened areas in  FIG. 4B , and the boat is anchored to the bottom of the stream by driving downward the anchor rods  50 ,  50 ′. Once in this position, the tugboat  60  is disconnected and moved away.  
         [0037]     Thereafter, a valve is opened to allow water from the stream to enter the hull of the boat. When the water level within the hull is the same as that of the rest of the stream, the hinged members  18 ,  18 ′ at the bow and the hinged member  22  are opened to allow water to flow through the hull, as shown in  FIG. 4C . By adjusting the opening angle, as well as the extensions  20 ,  20 ′ of the hinged members  18 ,  18 ′, it is possible to divert nearly all of the water that flows in the stream through the hull of the boat  10 . This water then acts on the paddles  32  to drive the electric generators.  
         [0038]     When it is desired to take the apparatus out of service, the hinged members  18 ,  18 ′ at the bow of the boat are closed and a tugboat  60  is again connected to the front of the boat, as shown in  FIG. 4D . Thereafter, the rods  50 ,  50 ′ are raised up and water is pumped from the tanks  48 ,  48 ′ to allow the boat to float. In order to empty the boat, the electric generators are operated briefly as electric motors to drive the sprockets  26 ,  27 ,  28  and  26 ′,  27 ′,  28 ′, thus move the paddles  32  in the same direction as they were moved by the flow of water. This action “sweeps” the water out of the hull towards the stern. When the hull is substantially empty, the stern member  22  is raised up and closed to seal the hull. If desired, the remaining water may be pumped out of the hull so that the boat  10  is relatively light and may be easily moved to another location.  
         [0039]     There has thus been shown and described a novel method and apparatus for retrieving energy from a flowing stream of water which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.