Abstract:
An air-blower tidal power generation device includes a rack, an air-blower mechanism, and a power generation mechanism. The air-blower mechanism includes a pumping device, a buoy, and an air conduit. The pumping device includes a cylinder and a stationary barrel movably coupled together. The power generation mechanism includes a constant-pressure and pressure-regulation device and a power generator having an air-driven turbine. Thus, tides move the buoy up and down to drive the pumping device for cyclically drawing and pumping air, and the air is preserved in the constant-pressure and pressure-regulation device to provide a constant pressure for subsequent and stable supply of airflow to the turbine for driving the power generator to generate power.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an air-blower tidal power generation device, and in particular to a power generation system that utilizes tides to move a buoy of an air-blower mechanism to drive a pumping device for drawing and pumping air into a constant-pressure and pressure-regulation device from which airflow is released under constant pressure to a windmill for rotating a power generator for generation of power and that is suitable for power generation device or similar devices operable at different sea areas to extract tidal energy and can be modularized for continuously extracting energy of tides with a simple construction. 
   BACKGROUND OF THE INVENTION 
   Due to increasing demand of fossil energy, the price of oil is constantly increased. Thus, the advanced countries, such as Japan and European countries, devote a great amount of effort to develop power generation with waves and tides, which is often realized by providing a tidal power generator that is operated by the up and down movement tides to generate electrical power thereby converting the tidal energy into electrical energy. It is estimated that the world&#39;s power consumption can be satisfied by five times if 0.1% tidal energy of the world is converted into electrical energy. The storage of tidal energy is amazingly large. 
   Tidal power generation has been developed for hundreds of years, but no technical breakthrough has been done. A known tidal power generation device is disclosed in U.S. Pat. No. 6,717,284 B2, in the name of the present inventor, comprising a rack, an air-blower mechanism disposed at a predetermined position of the rack, the air-blower mechanism comprising an extendible cylinder, a buoy mounted to an end of the extendible cylinder and a tube mounted to another end of the extendible cylinder, the bottom of the buoy being positioned on the sea surface; a power generation mechanism comprising an air canister and a power generator having a pneumatically operated motor, the air canister being coupled to the tube, whereby the tides drive the air-blower mechanism to directly extract energy from the up and down movement of the tides for providing compressed air into the air canister from which airflow is released to drive the pneumatically operated motor of the power generator to thereby realize an air-blower tidal power generation device. The device utilizes the up and down movement of the tides, which causes a substantial difference in the height of the sea surface, to continuously drive the air-blower mechanism whereby compressed air can be obtained in all situations of large/small tides and high/low tides and stored in the air canister for subsequent supply to the pneumatically operated motor for driving the power generator. In this way, large construction and complicated mechanism can be omitted and power generation can be realized with a simple structure of the air-blower type tidal power generation device. Costs of installation and operation and time and effort required for installing the device are both reduced, which also result in easy maintenance. 
   The conventional air-blower type tidal power generation device, although effective in simplifying the structure and reducing costs for convenient generation of electrical power, suffers a disadvantage of instable supply of airflow of substantially fixed pressure. This is due to the fact that the air compressed and filled into the canister by the air-blower mechanism is continuously accumulated inside the canister and the internal pressure of the canister is increased with air filled into the canister. Thus, it is in general impossible to maintain constant pressure. Also, when air starts to discharge from the canister, the internal pressure of the canister is lowered. Thus, stable supply of constant pressure airflow is in general impossible. 
   Thus, the present invention is aimed to provide an air-blower tidal power generation device to overcome the drawbacks of the conventional devices. 
   SUMMARY OF THE INVENTION 
   An objective of the present invention is to provide an air-blower tidal power generation device, which employs tides to move a buoy of an air-blower mechanism for driving a pumping device to draw and pump air into a constant-pressure and pressure-regulation device, which stores and maintains a constant pressure of the air for subsequent and stable supply of airflow under constant pressure to an air-driven turbine for driving a power generator to generate power, wherein the pumping device comprises a cylinder and a stationary barrel that are coupled in a relatively movable manner and an airtight and stable engagement is formed between the cylinder and the barrel so that an air-blower tidal power generation device can be realized. 
   Another objective of the present invention is to provide an air-blower tidal power generation device comprising a gravity-controlled constant-pressure and pressure-regulation device for stable supply of airflow under constant pressure from the constant-pressure and pressure-regulation device to an air-driven turbine for driving a power generator to generate electrical power. 
   A further objective of the present invention is to provide an air-blower tidal power generation device comprising a pumping device having a cylinder that is composed of a metal layer, an epoxy resin layer, and a plastic sheet layer to suit the requirements of light weight, wear resistance, pressure resistance, and low friction coefficient so as to improve durability thereof and to provide an efficient conversion of energy. 
   To realize the above objectives, in accordance with the present invention, there is provided an air-blower tidal power generation device comprising a rack, an air-blower mechanism, and a power generation mechanism. The air-blower mechanism comprises a pumping device, a buoy, an air conduit. The pumping device comprises a cylinder and a stationary barrel movably coupled together. The cylinder comprises a metal layer, an epoxy layer, and a plastic sheet layer. The metal layer serves an inner lining and has an outer circumference surrounded by the epoxy resin layer and circumferentially reinforced by retention frames. The epoxy resin layer has an outer circumference surrounded by the plastic sheet layer. The metal layer of the cylinder has an inside surface movably fit over and engaging the stationary barrel. The cylinder that is located at an end of the pumping device is mounted to the buoy and the stationary barrel located at an opposite end of the pumping device is connected to and in fluid communication with the air conduit. The air conduit is connected to an extension tube. The air conduit has an end forming an opening in which a check valve is mounted. Another check valve is arranged inside the extension tube. The rack serves to carry and support the air-blower mechanism therein. The power generation mechanism comprises a constant-pressure and pressure-regulation device and a power generator having an air-driven turbine. The constant-pressure and pressure-regulation device is connected to and in fluid communication with the extension tube. Thus, tides move the buoy up and down to drive the pumping device for cyclically drawing and pumping air, and the air is preserved in the constant-pressure and pressure-regulation device to provide a constant pressure for subsequent and stable supply of airflow to the turbine for driving the power generator to generate power. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments thereof with reference to the drawings, in which: 
       FIG. 1  is a perspective view of an air-blower tidal power generation device constructed in accordance with the present invention; 
       FIG. 2  is a cross-sectional view of an air-blower mechanism of the air-blower tidal power generation device of the present invention; 
       FIG. 3  is a cross-sectional view of a constant-pressure and pressure-regulation device of the air-blower tidal power generation device of the present invention; 
       FIG. 4  is a perspective view of a check valve of the air-blower tidal power generation device of the present invention; 
       FIG. 5  is a perspective view illustrating an application of the air-blower tidal power generation device of the present invention; and 
       FIG. 6  is a perspective view of an air-blower tidal power generation device constructed in accordance with another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the drawings and in particular to  FIGS. 1-4 , an air-blower tidal power generation device constructed in accordance with the present invention is shown. The air-blower tidal power generation device comprises an air-blower mechanism  10 , which comprises extendible/retractable pumping devices  11 , a buoy  12 , and an air conduit  13 . The extendible/retractable pumping device  11  comprises a cylinder  14  and a stationary barrel  15  movably fit in the cylinder  14 . The cylinder  14 , which is in contact with gas, is subject to the requirements of light weight, pressure resistance, wear resistance, and low friction coefficient. Thus, the cylinder  14  is comprised of a metal layer  141 , an epoxy resin layer  142 , and a plastic sheet layer  143 . The metal layer  141  serves as an inner lining and is made of a metal plate that is smooth, wear-resistant, and corrosion-resistant against sea water. Stainless steel is taken as an example in the illustration of the present embodiment. The metal layer  141  has an outer circumference around which the epoxy resin layer  142  wraps and a plurality of retention frames  183  are arranged to surround the outer circumference of the metal layer  141  to maintain the shape of the metal layer  141  of the cylinder  14 . The epoxy resin layer  142  has an outer circumference around which the plastic sheet layer  143 , of which an example is a thin sheet of polycarbonate (PC) wraps. The arrangement of the retention frames  183  around the outer circumference of the metal layer  141  and filling of the epoxy resin between the metal layer  141  and the plastic sheet layer  143  to form a sandwich structure realize the requirements of light weight, pressure resistance, wear resistance, and low friction coefficient. The metal layer  141  of the cylinder  14  has an inside surface fit over and engaging the stationary barrel  15  in a movable manner. A seal head  18  is provided around an outer circumference of the stationary barrel  15  at the portion of the stationary barrel  15  that is in movable engagement with the inside surface of the metal layer  141  of the cylinder  14 . The seal head  18  is made of aluminum casting and is provided with sealing rings  181  to eliminate gas leakage. On upper and lower sides of the sealing rings  181 , guide projections  182  that are wear resistant are provided on the seal head  18  to ensure stable up-and-down movement of the cylinder  14  with respect to the stationary barrel  15 . The cylinder  14  that is located at one end of the pumping device  11  is fixed to the buoy  12  and the stationary barrel  15  that is located at an opposite end of the pumping device  11  is in fluid communication with the air conduit  13 . The air conduit  13  is connected to an extension tube  16 . One end of the air conduit  13  forms an opening  17  and a check valve  40  is mounted to inside surface of the air conduit  13  in proximity to the opening  17 . Another check valve  41  is arranged inside the extension tube  16 . The check valves  40 ,  41  are composed of a ring  42  and a flap  43 . The ring  42  has a circumferential wall in which an opening  421  is formed. A circumferential rib  422  is formed along an inside surface of the circumferential wall of the ring  42  to effect tight engagement between the ring  42  and the flap  43 . The flap  43  has mounting sections  431  that are movably received in and retained by opposite ends of the opening  421  thereby forming a resistance-free check valve structure that allows for unidirectional flow of fluid there through. 
   A rack  20  comprises a bottom  21  and a top  22  between which at least one frame member  24  is connected. The buoy  12  of the air-blower mechanism  10  is movably fit over at least one of the frame members  24 . The top  22  is provided with an accumulator  25  having an end in fluid communication with the pumping devices  11  and another end in fluid communication with the air conduit  13  to collect air pumped by the pumping devices  11  and conduct the air collected to the air conduit  13 . 
   A power generation mechanism  30  comprises a constant-pressure and pressure-regulation device  31  and a power generator  32  having an air-driving turbine or windmill. The constant-pressure and pressure-regulation device  31  is connected to the extension tube  16  of the air-blower mechanism  10 . The constant-pressure and pressure-regulation device  31  comprises a canister  33  and a weight block  34 . The canister  33  has an air outlet  331  and an air inlet  332  and support blocks  333 . The support blocks  333  are mounted on and extend from a bottom of the canister  33  to a height that is higher than the locations of the air outlet  331  and the air inlet  332 . The air outlet  331  is provided with a flow control switch  337  for regulating airflow rate through the air outlet  331 . The canister  33  is constructed with a metal layer  334 , an epoxy resin layer  335 , and a plastic sheet layer  336 . The metal layer  334  serves as an inner lining, which is metal plate that is smooth, wear resistant, and corrosion resistant against sea water. Stainless steel is taken as an example of the metal plate that makes the metal layer  334  in the embodiment illustrated. An outer circumference of the metal layer  334  is surrounded by the epoxy resin layer  335  and is provided with reinforcing frames  338  to maintain the shape of the metal layer  334  of the canister  33 . An outer circumference of the epoxy resin layer  335  is surrounded by the plastic sheet layer  336 , which in the embodiment illustrated comprises a thin sheet of polycarbonate (PC). With the arrangement of the reinforcing frames  338  around the outer circumference of the metal layer  334  and filling the epoxy resin between the metal layer  334  and the plastic sheet layer  336  to form a sandwich structure, requirements of being light-weight, pressure-resistant, and of low friction coefficient can be met. An inside surface of the metal layer  334  is movably fit over and engages a seal head  35 . The weight block  34  is mounted on the seal head  35 . The canister  33  is maintained stationary, while the seal head  35  and the weight block  34  are movable up and down with the increase and decrease of the amount of air stored inside the canister  33 . The seal head  35  is made of aluminum casting and is provided with sealing rings  36  to eliminate air leakage. The seal head  35  is further provided with wear-resistant guide projections  37  on upper and lower sides of the sealing rings  36  to guide stable up-and-down movement of the weight block  34  and the seal head  35  inside the canister  33 . When substantially no air is preserved inside the constant-pressure and pressure-regulation device  31 , the weight block  34  and the seal head  35  rest on the support blocks  333  inside the canister  33 . 
   Referring to  FIGS. 1-5 , in a practical application, the air-blower tidal power generation device is positioned in sea tides. The bottom  21  of the rack  20  can be further added with an anchoring base  211 , depending upon the situation of the sea where the device is mounted. In mounting the device, a bottom side of the buoy  12  is positioned as close as possible to the sea surface so that the buoy  12  can move up and down with the tides and thus drives the cylinders  14  of the pumping devices  11  to draw air into the cylinders  14  and forces air into the accumulator  25  arranged on the top  22  of the rack  20 . The check valve  40  that is located inside the air conduit  13  is closed and prevents air to flow out of the opening  17  of the air conduit  13 , while the check valve  41  located inside the extension tub  16  is open to allow the air to move along the extension tube  16  into the constant-pressure and pressure-regulation device  31 . When air is filled into the constant-pressure and pressure-regulation device  31 , the increased air pressure inside the constant-pressure and the pressure-regulation device  31  closes the check valve  41  inside the extension tube  16  thereby securing the air inside the constant-pressure and pressure-regulation device  31 . When tides go down, the cylinder  14  of the pumping device  11  is lowered downward by gravity. The internal pressure is reduced, and the check valve  40  inside the air conduit  13  is open to draw air into the air conduit  13 . Again, when tides go up, the cylinder  14  is pushed upward and air inside the air conduit  13  is compressed again, which closes the check valve  40  again. The opening/closing of the other check valve  41  is exactly opposite to that of the check valve  40  so that air can be repeatedly drawn into the air conduit  13  (through the check valve  40 ) and pumped to the constant-pressure and pressure-regulation device  31  (through the check valve  41 ). The air filled into and preserved in the constant-pressure and pressure-regulation device  31  is maintained at a constant pressure due to the fact that the weight block  34  provides a fixed gravitational force that is counteracted and thus balanced with the air pressure inside the canister  33 . Thus, airflow that is induced under the constant pressure can be stably supplied from the constant-pressure and pressure-regulation device  31  to drive the power generator  32 . Thus, in accordance with the present invention, the tides (and gravity) moves the buoy  12  of the air-bower mechanism  10  to cause the cylinder  14  to cyclically draw and pump air and the compressed air is preserved in the constant-pressure and pressure-regulation device  31  for continuous and stable supply of airflow to the turbine of the power generator  32  for generation of power. 
   Referring to  FIGS. 1-6 , a second embodiment of the present invention is shown, wherein a movable rack  50  is provided to carry the system of the present invention to any desired location where the situation of tides is suitable. Thus, the present invention can be selectively installed at any environment or directly mounted in the sea, as shown in  FIG. 5 , or alternatively, the system of the present invention can be installed in a vessel or ship to be transported to any suitable location in oceans and seas to extract tidal energy and in case of bad weather, the whole system can be moved back to a home harbor with the ship. 
   Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.