Patent Publication Number: US-8978570-B2

Title: Lifting floor for bodies of water

Description:
RELATED APPLICATION 
     This application claims priority from U.S. Provisional Application Ser. No. 61/583,453, filed on Jan. 5, 2012, entitled EMERGENCY LIFTING FLOOR FOR LARGE POOL OR POND, the entirety of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to lifting floors for open bodies of water and enclosed pools. The invention is especially directed to emergency lifting platforms capable of raising a substantial load to the surface of a large pool in a very short period of time. 
     BACKGROUND OF THE INVENTION 
     Lifting floors for large bodies of water are known for lifting objects, such as boats from marina harbors and lifting humans in small enclosed pools. U.S. Pat. No. 5,692,857 also discloses a lifting platform for raising a large mammal to the surface of an enclosed pool. 
     Nothing in the prior art, however, suggests or discloses a lifting platform capable of lifting a very large load to the surface of a body of water in a very short period of time. There is a need for such a lifting platform to address, for example, emergency situations which arise with large aquatic mammals in large enclosed pools. 
     SUMMARY OF THE INVENTION 
     The invention satisfies this need. The invention is an emergency lifting floor  10  for raising the entire floor in an open body of water or enclosed pool. The invention can be used for many purposes, but it is especially directed to lifting one or more large aquatic animals, such as killer whales, to above the surface of an aquatic amusement park pool under emergency conditions. 
     In a broad sense, the lifting floor comprises (a) a plurality of float modules, each float module having a hull with downwardly extending side walls, a top wall, a bottom and a buoyancy compartment, each float module being attached to adjacent float modules by means of flexible joints; (b) at least one container disposed in each float module for retaining a buoyancy fluid having a density less than that of water; and (c) a discharge apparatus for discharging buoyancy fluid from each container, so as to fill the buoyancy compartment of some or all of the float modules with buoyancy fluid, thereby causing the plurality of modules to float to a position at or near the surface of the body of water 
    
    
     
       DRAWINGS 
       These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying drawings where: 
         FIG. 1  is a perspective view of a lifting floor having features of the invention, shown near the bottom of an enclosed pool; 
         FIG. 2  is a perspective view of the lifting floor illustrated in  FIG. 1 , shown near the top of the enclosed pool; 
         FIG. 3  is a perspective view of a module used in the lifting floor illustrated in  FIG. 1 ; 
         FIG. 4  is an exploded view of the module illustrated in  FIG. 3 ; 
         FIG. 5  is a perspective view showing the underside of the module illustrated in  FIG. 3 ; 
         FIG. 6  is a perspective view of the hull of the module illustrated in  FIG. 3 ; 
         FIG. 7  is a perspective view illustrating an edge module used in the lifting floor illustrated in  FIG. 1 ; 
         FIG. 8  is a perspective view of a portion of the lifting floor illustrated in  FIG. 1 , showing a pair of pool edge access doors; 
         FIG. 9  is a perspective view of a buoyancy assembly used within the module illustrated in  FIG. 3 ; 
         FIG. 10  is a perspective view illustrating a module such as illustrated in  FIG. 5  having a tether attached thereto; 
         FIG. 11  is a perspective view of an enclosed pool having portions of a stabilizer apparatus disposed therein; and 
         FIG. 12  is a perspective view of the module illustrated in  FIG. 3  showing additional portions of stabilizer assembly illustrated in  FIG. 11  attached to a module. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following discussion describes in detail one embodiment of the invention and several variations of that embodiment. This discussion should not be construed, however, as limiting the invention to those particular embodiments. Practitioners skilled in the art will recognize numerous other embodiments as well. 
     The invention is a lifting floor  10  for use in a body of water. The body of water is typically a large confined pool, but it can also be an open body of water, such as a marina or other boat harbor. The lifting floor  10  comprises a plurality of float modules  12 , at least one container  14  disposed in each float module and a discharge apparatus  16 . 
     The lifting floor  10  is designed to reside on the bottom of a body of water, and, when required, use buoyancy assemblies  32  to blow air or other low density fluid into buoyancy compartments  28  within each float module  12 —thereby causing the lifting platform  10  to rise to at or near the surface in a very short period of time, if necessary. By “near the surface,” it is meant within about 30 inches of the surface, typically within about 18 inches of the surface. 
     The time for the emergency lifting floor  10  to deploy to the raised position in an emergency situation is typically 30 to 60 seconds, depending on water depth. 
       FIG. 1  illustrates one embodiment of the lifting floor  10  disposed on the bottom of an enclosed pool  18 .  FIG. 2  illustrates the same embodiment raised to near its maximum height within the pool  18 . 
     The plurality of float modules  12  is flexibly connected to one another to yield an integral whole. All module-to-module gaps are typically about standard 6″ width, and are preferably filled by grating. 
     The plurality of float modules  12  typically comprises standard modules  12   a  and edge modules  12   b . Standard float modules  12   a  are used to cover as much of pool area as possible.  FIG. 3-6  illustrate a typical standard float module  12   a.    
     Each float module  12  comprises a hull  20  with downwardly extending side walls  22 , a top wall  24 , a bottom  26  and a buoyancy compartment  28 . In a typical embodiment, an outer wall  22   a  and an inner wall  22   b  of the hull side walls  22  together define the buoyancy compartment  28  therebetween. 
     The bottom  26  of each float module  12  is typically at least partially open and can be made of a concrete to provide proper ballast. 
     The hull  20  of each standard float module can be a hollow polyethylene rotomolded part. The skin thickness can be about 0.25 inches. The side walls  22  can have a hollow double wall construction, comprising a total thickness 0.375 inches-0.5 inches, and comprising concrete and/or foam fill. Concrete fill allows the final weight to be adjusted for the desired buoyancy. Foam fill assures that the modules  12  will not fill with water and provides additional stiffening. The foam is preferably hydrophobic. 
     The hull  20  of each module  12  defines a large central opening  29  covered by a grate  30 . The grate  30  is typically made of deck grating of an open style fiberglass that allows water to flow through the module  12  during ascent and descent. Access hatches are provided in selected modules  12  to allow diver access to the area below the lifting floor  10  when the lifting floor  10  is raised. The grate  30  is removable for access to buoyancy assemblies  32  disposed within each module  12 . 
     Disposed within each module  12  is a buoyancy assembly  32  comprising a container  14 , associated valves and connecting tubing. 
     Each float module  12  further comprises at least one flood valve  34  to allow water to refill the buoyancy compartment  28 . The flood valve  34  can be an air actuated flap mechanism mounted near the top of the buoyancy compartment  28 . The flood valve  34  is normally held closed by springs. When actuated, a pneumatic air bag style actuator forces the flaps to an open position allowing the air to be vented from the buoyancy compartment  28 , thereby flooding the buoyancy compartment  28  and making the module  12  negatively buoyant for descent. To minimize trapped air when the lifting floor  10  is not level, two flood valves  34  are preferably mounted on opposite ends of standard float module  12 . 
     The underside of each standard float module  12   a  comprises a plurality of support feet  36  which can be made from either a plastic or a metal material. The support feet  36  are dimensioned for leveling the module  12   a  and allowing it to stand evenly a few inches above the floor of the pool  18 . 
     The standard modules  12   a  typically have a square top side area of between about 3 square feet and about 10 square feet. In a typical embodiment, the standard float modules  12   a  are 24-36 inches tall. In one example, the standard float modules  12   a  have approximately 7 square feet of top side area and are 32.5 inches tall. 
     The lifting floor  10  of the invention can be adapted for use in pools  18  of different depths. In a typical application, the pool depth is between about 15 and about 35 feet. Deeper pool applications can utilize a 36-inch tall float, while shallow pool applications can utilize a 24-inch tall float module  12 . 36-inch float modules  12  have a large central opening  29  for increased flow and faster rise speeds to account for the longer travel distance in a deep pool. 24-inch float modules  12  have a smaller central opening  29 , since a slower flow rate and rise speed are required at shallower depths. 
     Each float module  12  is attached to adjacent float modules  12  by means of flexible joints  38 . Typically, the flexible joints  38  are disposed at the corners of each module  12  and are each attached to a link retainer  40  formed into the corners of each module  12 . Each link retainer  40  is typically made from a polyurethane or other plastic and can be held in place with metal rods  42 . 
     Preferably, the lifting floor  10  is disposed sufficiently proximate to the walls of the pool  18  so as to prevent a human being from falling from the lifting floor  10  between the lifting floor  10  and the walls of the pool  18 . It is also important in the invention that the lifting floor  10  be sufficiently close to the pool walls to prevent aquatic mammals from gaining access below the lifting floor  10 . Accordingly, the lifting floor  10  is preferably adapted to the shape of the pool  18  where it is employed. In order to accommodate each pool shape, the periphery is fitted with edge float modules  12   b  that are custom shaped to closely fit the plan view of the pool  18 . 
     The edge float modules  12   b  are typically made of metal, but are otherwise comprised of the components of the standard float modules  12   a . The edge float modules  12   b  have corners which are individually shaped along one or two side edges to allow each of the edge float modules  12   b  to closely match the surface dimensions of the pool  18 . 
     The edge float modules  12   b  preferably comprise bearing surfaces or bumpers capable of contacting the side walls  22  of the pools  18 . Alternatively, the edge float modules  12   b  can comprise rollers capable of contacting the walls of the pool  18 . 
     In pools  18  having a bottom with a slanted perimeter, the edge modules  12   b  preferably comprise a sloped bottom  26  capable of contacting the slanted perimeter of the pool bottom when the lifting floor  10  is disposed proximate to the pool bottom. Pads are preferably provided at the bottom of each module  12  whenever the module  12  rests against the pool bottom. 
     As illustrated in  FIG. 7 , in pools  18  having a bottom  26  with a slanted perimeter of exceptional width, the edge modules  12   b  preferably comprise an edge wall  44  cantilevered off of the edge module  12   b  at an angle matching the slope of the slanted perimeter. The edge walls  44  are preferably of sufficient length to reach within about 4 inches of the pool walls. Plastic rollers  46  on stainless tube shafts can be affixed to the ends of the edge walls  44  to prevent undue friction between the edge walls  44  and the pool walls. 
     As illustrated in  FIG. 8 , access gates  48  can be provided in one or more of the edge walls  44  to allow access between the lifting platform  10  and the area surrounding the pool  18 . 
     In pools  18  having corners, the edge modules  12   b  typically comprise one or more corner modules  12   c , custom shaped to match the shape of the pool corners. 
     As noted above, each container  14  is a component of a buoyancy assembly  32  disposed within each float module  12 .  FIG. 9  illustrates a typical buoyancy assembly  32 . 
     Also as noted above, each container  14  is capable of retaining an operable supply of low density fluid. In the embodiment illustrated in the drawings, the container  14  is a compressed air tank, capable of retaining an operable supply of compressed air. Each container  14  has a discharge port adapted to discharge buoyancy fluid into the buoyancy compartment  28 . 
     The buoyancy assembly  32  typically further comprises (i) a check valve for allowing the air tank to be pressurized and for preventing air from escaping from the container  14  and (ii) a blow valve  52  attached at each discharge port which is remotely operated to allow air from the container  14  to escape into the buoyancy compartment  28 . 
     Each blow valve  52  is either pneumatically or electrically operated. Thus, the blow valves  52  can be solenoid valves or air actuated poppet valves. A shore based electrical signal can active each solenoid valve. A shore based air discharge activation signal can actuate each poppet valve. The solenoid valve or poppet valve typically comprises the pressure in air tanks at 2500-4000 psi charge level. When actuated, each blow valve  52  opens to fill the buoyancy compartment  28  with air, thereby causing the module  12  to be positively buoyant for ascent. 
     A discharge apparatus  16  is provided within each buoyancy assembly  32  to open some or all of the blow valves  52 , so as to fill each buoyancy compartment  28  with buoyancy fluid, thereby causing the plurality of modules  12  to float to a position at or near the surface of the body of water. 
     Preferably, the discharge apparatus  16  is capable of opening all of the blow valves  52  simultaneously or within a few seconds of one another, such as within 3-10 seconds of one another. As noted above, it is preferable that the opening of a majority of the blow valves  52  can be actuated from a location disposed distant from the lifting floor  10 . 
     In the embodiment illustrated in the drawings, associated on board electrical and electronic control components are housed in an electrical component pod  53  disposed in each module  12 . 
     Preferably, the discharge apparatus  16  comprises a programmable logic controller continued capable of being programmed to open the blow valves  52  in individual modules  12  at predetermined time intervals to maintain trim stability of the lifting platform  10  during ascent. 
     In pneumatic systems, the blow valves  52  are preferably actuated by two actuator valves. The two actuator valves are interconnected to provide redundancy. The redundancy gives the discharge opening apparatus  16  the ability to raise the lifting floor  10  in the event of a failure of a single actuator valve. 
     A high pressure charge air line is typically connected to the manifold to allow the air tanks to be monitored and charged from a shore based air compressor and monitoring system. In this regard, a high pressure recharge air compressor and dryer system can be provided. A high pressure recharge system is also provided, including plumbing or piping as required to transmit high pressure air to the control valve location(s). Pneumatic piping is typically used between the local pool control valve locations. Piping is provided from the control valve locations to the lifting floor  10 . Piping is also provided to the control valve locations from a source of air compression, such as an air compressor and high pressure air supply system. The charge air line may or may not be permanently attached. The charge air line also allows make-up air to be pumped into the lifting floor  10  when the lifting floor  10  is raised to overcome any incidental leakage in the float modules  12  and maintain the lifting floor  10  in the raised position indefinitely. 
     In each module  12 , the net lifting force with a fully blown buoyancy compartment  28  is typically 2,500-3,000 lbs. 
     Local operational control stations are provided to initiate emergency raise, routine raise and routine lower motions. Typically, one to three guarded pushbutton panels per pool  18  are used to initiate the emergency raise motions. The routine raise and lower positions are typically initiated via a separate dedicated push-button panel. 
     Typically, on shore control valves are located in enclosures. Each enclosure is preferably located as close as possible to the edge of the pool  18 . 
     As noted above, a central programmable logic controller is used to monitor and control the lifting floor  10  throughout the facility. The controller;
         Interfaces with the operator and monitoring stations   Provides the valve control sequencing for different operating modes   Provides system status monitoring and error annunciation   Provides manual control functions for system maintenance and debugging   Controls and confirms the closing of any gates used to allow access from the pool  18  to an adjoining pool.       

     The controller can be located in an electrical enclosure along with appropriate power supplies, control relays and distribution equipment. 
     As noted above, during raising operations, the lifting platform  10  can be controlled by opening the blow valves  52  in a programmed sequence. The inner module blow valves  52  are typically activated first, followed by perimeter module blow valves  52 . 
     To initiate lowering operations, the flood valves  34  are automatically cycled to bring the lifting floor  10  to the bottom of the pool  18 . During lowering operations, the lifting floor  10  can be controlled by reacting to lifting floor depth. A command to lower the lifting floor  10  causes the flood valves  34  to activate and the blow valves  52  to pulse to maintain attitude/levelness/trim stability. A control system algorithm used in lower operations is based on a virtual axis. The virtual axis is the target depth versus time. Each control zone is plotted and compared to virtual axis. At specified increments, the control system calculates the difference between actual depth and virtual depth. The blow valve  52  activation time is calculated using the depth difference and a predetermined gain. The gain is a predetermined program variable. 
     Typically, an audible alarm is adapted to sound whenever the lifting floor  10  is activated. The alarm type and duration can vary depending on if the lifting floor  10  is activated in emergency or routine maintenance mode. 
     The controller is typically disposed in a monitoring station located in a central, control booth. Remote operator stations can be also be provided for routine operation of an individual lifting floor  10  assembly. Remote operator stations are preferably located within direct line of sight of the pool  18 . The remote operator stations are used for routine operation of the lifting floor  10 . Additional control stations can be located around the pool  18  to trigger emergency lifting floor deployment. 
     The lifting floor  10  can further comprise a stabilizer apparatus  54  for stabilizing the plurality of modules  12  during the ascent through the body of water and/or during the time that they are at a position near the surface of the body of water. 
     In open water applications, the stabilizer apparatus  54  can be employed to prevent the lifting floor  10  from fully rising to the surface. Often, restricting the rise of the lifting floor  10  to within about 6 and 18 inches (for example, approximately 12 inches) of the surface is preferred to minimize the effect of wind and waves on the lifting platform. In one embodiment, tethers  56  and anchor assemblies are used to limit the upward travel of the lifting floor  10 . A typical tether  56  and anchor assembly is illustrated in  FIG. 9 . The upper end of each tether  56  is attached at its upper end to the float modules  12 . The lower end of each tether  56  is attached to an anchor  57  at the bottom of the body of water. 
     As illustrated in  FIGS. 11 and 12 , in enclosed pool applications, the stabilizer apparatus  54  can comprise cords  58  slidably attached to the bottom of the pool  18  and fixed to one of the modules  12 . Each cord  58  is capable of being unwound under tension from the drum of a winch  60  so as to retard portions of the lifting platform  10  during the raising of the lifting platform  10 . In such a stabilizer apparatus  54 , an external trim control system is used to monitor and control vertical stability of the overall lifting floor  10  during ascent. The purpose of this stabilizer apparatus  54  is to restrain a “runaway” module  12  from rising too quickly, to maintain lateral stability of the entire lifting floor  10  when it is at or near the surface and to maintain lateral position of the lifting floor  10  when it is being lowered to the pool bottom. 
     In this stabilizer apparatus embodiment, the cords  58  are typically strung within turning sheaves attached to the pool bottom. The sheaves preferably have “keepers” to maintain cords  58  in their grooves if they become slack. Cords  58  feed along the pool bottom and up the side of the pool wall to a winch  60  located pool-side. The cords  58  reel-in and pay-out in unison using a position control system. A host processor checks to see that all the modules  12  are within an allowable elevation window of each other. A typical winch motor is a 20 hp electric VFD gear motor. 
     The winches  60  are located at a winch location  62  disposed beyond one end of the pool. Edge sheaves are typically used to route the cords  58  from the winch  60  location down the pool wall. Corner sheaves are used to route the cords  58  along chamfers to the bottom of the pool  18 . Floor sheaves route the cords  58  along the bottom of the pool to flagging sheaves. Flagging sheaves route each cord  58  to one or more connection points on selected modules  12 . Typically, one pair of inter-module connectors  64  located at a module corner is used to anchor each cord connection. The vertical rise of each cord  58  to the pair of inter-module connectors  64  can be shrouded in a connector tube  66 , typically a stainless steel tube. A second pair of inter-module connectors  64  can be used to help react bending (for tension at the pool bottom). 
     The winches  60  are typically enclosed in a housing for visual shielding and for protection of the winches  60  and associated equipment from the elements. The wall of the pool  18  can be shielded from the cords  58  by a shroud  68  disposed along the vertical rise of the pool wall. 
     In a large enclosed pool  18 , wherein the lifting floor  10  has an ascent rate of about 9 feet per second, a typical gross restraint level of the stabilizer apparatus  54  is of the order of 100,000 pounds. For such a restraint level, 8 to 10 cords  58  can be used. Each of the cords  58  can be made of high modulus polyethylene (HMPE). Plasma 12-strand cord having a diameter of one inch can be employed. Such plasma 12-strand cord can be obtained from the Cortland Company of Cortland, N.Y. 
     An alternative stabilizer apparatus  54  for closed pools  18  can comprise actuators attached to the bottom of the lifting floor  10 , the actuators being fluidically energized so as to controllably assist or retard the lifting floor  10  during the raising and lowering of the lifting floor  10 . 
     Another alternative stabilizer for an enclosed pool  18  can comprise an ascent retarding device mounted within at least one float module  12 . The retarding device is a tuneable flow-limiting orifice or a winch  60  having a cord  58  with a retractable end attached to the floor of the pool  18 . 
     Preferably, the lifting floor  10  is capable of raising a load of 1000 pounds from a position proximate to the bottom of a body of water having a depth of 25 feet to a position close to the surface of the body of water in less than about 60 seconds. 
     A typical embodiment directed to the raising of multiple aquatic mammals, such as killer whales, is designed for a total asset weight of 40,000 lbs. 40,000 lbs is the approximate weight of four large aquatic mammals weighing 7,000 lbs. and four large aquatic mammals weighing 3,000 lbs. Typically, the maximum individual asset weight is 12,000 lbs. 
     Once in the raised position, the lifting floor  10  is stable and allows for the movement of personnel across any area of the lifting floor  10  to deal with any emergency. 
     After deployment of the raised position, the lifting floor  10  can be lowered to the pool bottom by controlled flooding of the buoyancy compartments  28 . Humans and/or aquatic mammals may be present when the lifting floor  10  is lowered. 
     The lifting floor  10  is preferably equipped with lock-out/tag-out capability to allow for safe service, maintenance and cleaning of the lifting floor  10  and all areas under the lifting floor  10 . 
     Also, all components which may come in contact with aquatic mammals or personnel are preferably free of sharp edges or loose parts. 
     Preferably, the lifting floor  10  is designed for a long life, such as a 20-year life. Typically, it is designed for one cycle every week, which is the equivalent of 1040 total cycles over a 20-year period. Materials used in the construction of the invention should be suitable for extended service life in the aqueous atmosphere present in the pool—such as in a chlorinated and ozonated artificial saltwater or natural seawater operating environment. Materials are selected to minimize the occurrence of discoloration, oxidation, or corrosion of each component. 
     The lifting floor  10  can be implemented in a variety of pools  18  at a single location. The lifting floors  10  for all of the pools  18  at a single location can be supported by a centralized system to provide controls for raising and lowering the individual pool lifting floors  10  and a high pressure compressor system to recharge the air tanks mounted in the float modules  12 . 
     Having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the instant invention as set forth hereinabove and as described herein below by the claims.