Abstract:
A CO 2  generating and dispensing device having container with a first space for receiving oxalic acid and water, and a second space for receiving a CO 2  generator which generator is attached to a lid. The lid secures to the container. Two conductive rods extend above the lid and are attached to the CO 2  generator. Electric current is applied to the rods which initiates the CO 2  generation. Generated CO 2  rises from the second space and out a discharge vent on the lid. An hose attached to the discharge vent direct the CO 2  to a pre-determined destination.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of nonprovisional application, application Ser. No. 11/650,016 filed on Jan. 5, 2007 now U.S. Pat. No. 7,785,450, which claims the benefit of U.S. Provisional Application No. 60/765,392, filed on Feb. 3, 2006. 
    
    
     STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT 
     The research and work for the development of this entire carbon dioxide generation process and the components associated therewith is partially funded by a United States Department of Agriculture grant, Grant Number 2006-33610-17503. 
    
    
     BACKGROUND 
     This device relates to an improvement in the generation of carbon dioxide, and more particularly to a self-sustaining, on-site generation of carbon dioxide. 
     Commercial carbon dioxide is widely used and is generally manufactured by separation and purification from carbon-dioxide-rich gases produced by combustion or by biological processes. It is also found in underground formations in some states. Carbon dioxide is also commercially available as high-pressure cylinder gas [about 300 psig], in refrigerated liquid form, or as a solid [dry ice]. 
     Common uses of carbon dioxide include, among other uses, use in fire extinguishing systems, for carbonation of soft drinks and beer, freezing of food products, refrigeration and maintenance of environmental conditions during transportation of food products, enhancement of oil recovery from wells, materials production [such as plastics and rubber], and treatment of alkaline water, as a shield during welding where it protects the weld against oxidation, dry ice pellets for sand blasting surfaces without leaving residues, in the chemical processing industry such as methanol production, for priming oil wells to maintain pressure in the oil formation, for removing flash from rubber or plastic objects by tumbling with dry ice, for the creation of inert blankets or environments, for the prevention of fungal and bacterial growth, as an additive to oxygen for medical use, as a propellant in aerosol cans, and to aid in maintaining a level of 1000 ppm in green houses to increase production yields of vegetables and flowers, to name a few. 
     To meet the needs of these various applications, requiring from small quantities of carbon dioxide (less than a pound/day) to extremely large quantities (tons/day), carbon dioxide is available as a compressed gas requiring heavy cylinders, or a liquid under pressure available from tube or liquid trailers, or as solid dry ice. 
     Very small users rely on high pressure cylinders. Their distribution is generally conducted by locally-focused businesses that buy the gas in bulk liquid form and package it at their facilities. Small to medium size customers truck-in bulk liquid products that are then processed through evaporation to produce the gas. Larger customers&#39; needs are often met with “tube trailers”, i.e., bundles of high-pressure cylinders mounted on wheeled platforms. Onsite” plants are usually installed by customers consuming more than 10 tons/day of the gas. 
     There is an increasing interest in user-owned, small, non-cryogenic gas generators, in many markets. Such generators are available for oxygen, hydrogen and nitrogen, but not for carbon dioxide. For example, small to medium size users of oxygen or nitrogen may find an economical supply alternative in pressure-swing-adsorption (PSA) plants. Or again, hydrogen and oxygen may be produced through electrolysis of water. High purity hydrogen may then be produced by purification of the stream by using palladium foil diffusers. 
     To-date, “on-site” economical carbon dioxide generators, such as are available for hydrogen and oxygen, do not exist, although the demand for carbon dioxide is substantial. Moreover, the benefits of these “on-site” generators are multiple. For example, generation on demand, as needed independence from suppliers and possible supply interruptions, cost-insensitivity to supply issues no need for pressure vessels, their storage and recycling, and the like. 
     To meet this need, applicant has invented an electrolytic process and methods to produce carbon dioxide from organic acids which were originally described in U.S. Pat. Nos. 6,780,304 and 6,387,228. Applicant has pursued the development of that generation technology by developing multiple electrochemical cells assembled in stacks to achieve production rates and volumes much larger than those described in these patents. 
     Continuing in this vein, applicant has now designed an entire, self-sufficient carbon dioxide generation system comprised of solar panels, an electronic control unit for the transfer of solar energy to a battery, an electronic control module controlling the current output to an electrochemical carbon dioxide generator [electrolyzer] such as disclosed in applicant&#39;s pending application, application Ser. No. 11/650,016 filed on Jan. 5, 2007, which is hereby incorporated by reference. 
     The preferred mode utilizes the carbon dioxide generator disclosed in applicant&#39;s pending application [&#39;016] which comprises a stack of at least two electrochemical cells, though any on-site carbon dioxide generator suited for the intended purpose may be used. The targeted carbon dioxide generation rate was 12 Liters/hour (0.05 lb/hr) for a duration of 10 hours per day, however, the system has been designed to, and can, generate in excess of 45 L/hr (0.18 lb/hr). 
     To create the self-sufficient carbon dioxide generation system applicant first devised a novel process to produce solid oxalic acid [OA] toroidal “briquets” weighing about 2 kg. each for placement and use in the novel dispenser. This generation and dispensing device designed by applicant forms the primary subject matter of this current application. Assembling and placing four such toroidal briquets into the device would allow for autonomous system operation and carbon dioxide generation for about one month, provided adequate solar energy can be harvested to sustain operation. 
     These oxalic acid [OA] toroidal briquets are used as the source for carbon dioxide generation. Anhydrous OA contains as much as 97.7 wt % carbon dioxide and therefore is the preferred source though, in some instances, oxalic acid dihydrate [OA 2H 2 O] can also be used. As developed by applicant, each toroidal briquet has an external diameter of approximately 25 cm, an internal diameter of approximately 10 cm, a thickness of approximately 3.5 cm, and weighs approximately 2.1 kg. A single toroidal briquet is adequate to support operation, at the nominal 12L/hr rate, for up to 9 days. As many as four such toroidal briquets can be stacked up in applicant&#39;s generating and dispensing device. 
     It should be understood that the size and dimensions of the toroidal briquet can vary as can the dimensions of the generating and dispensing device to accommodate the varying sizes of the toroidal briquet. 
     The toroidal briquets are compact, solid OA that can be easily handled without undue precaution. The ability to stack these toroidal briquets is the key component of the sub-system which makes the generating and dispensing device the vital and indispensable component thereof. The generating and dispensing device has an inner chamber inside of which the carbon dioxide generator of my pending application [&#39;615], one or more, may be housed and outside of which the toroidal briquets are stacked. An upstanding inner cylindrical wall [central pipe] extending from the floor of the generating and dispensing device up to approximately its top form a barrier between the carbon dioxide generator and the toroidal briquets. With current applied to the carbon dioxide generator and the desired carbon dioxide generation rate is set, the system will generate carbon dioxide without any human oversight, interface, or maintenance. 
     Through experimentation is has been shown that the system is capable of producing approximately 9.12 L/hr of carbon dioxide per amp. A current load of approximately 1.32 amps has been shown to be adequate to achieve the nominal carbon dioxide generation rate. A current load of approximately 3.29 amps has proven to be adequate to generate approximately 30 L carbon dioxide/hr. 
     Under these current loads the voltage applied to an electrolyzer, for example, holding 10 electrochemical cells, in series connection, is approximately 12 volts. Consequently, a 12-volt battery should be adequate for the entire system for adequate operation and uninterrupted and unsupervised carbon dioxide generation. The nominal power requirement should be between approximately 16 watts to approximately 40 watts for a maximum rate of production of approximately 30 L/hr of carbon dioxide. With the system operating for approximately 10 hours/day, the total daily energy required will be approximately 160 to 400 watt-hours. 
     The container of the generating and dispensing device is approximately 30 cm in diameter and approximately 16 cm high. The upstanding inner cylindrical wall [or central pipe] has a diameter which is smaller than the diameter of the inner diameter of the toroidal briquet. Given this configuration it can been seen that up to four toroidal briquets can be staked into the container. A lid is securely attached to the container. It has through holes for the stack terminals and the exhaust gas. The thick-walled container has been especially molded for this application. The toroidal briquets are to be located between the outer wall of the container and its upstanding inner cylindrical wall. As previously mentioned, this upstanding inner cylindrical wall is attached to the floor of the container and prevents the OA toroidal briquets from interfering with the extraction of the stack of toroidal briquets, should maintenance be required. 
     Before operation approximately 1-2 pints of water are poured into the container to initiate the process to dissolve the bottom most OA toroidal briquet. 
     The system has been designed to operate during night-time hours. Therefore any solar-generated energy is to be stored for nighttime consumption. The battery described above is selected on the basis of its ability to store sufficient energy for 1-2 days of operation during cloudy days. The battery voltage is selected for its compatibility with solar panels and the current load required by the electrolyzer [carbon dioxide generator]. As noted above a 12-volt, 55 A-hr battery is adequate for the nominal generation rate. The battery selected is a 490T SunXtender. A larger battery such as a 560T or 690T model with storage capacity of 63 and 79 A-hr will be needed for the sustained operation at 30 L/hr. 
     Two control units are necessary to the operation of the system as described; a conventional commercially-available charge controller and a commercially-available modified load current controller. A typical charge controller, such as a Steca PR 110 unit is suitable for the intended purpose. Its main function is the regulation of current and voltage between panels and the battery to optimize battery charging without overload, and the like. 
     The load controller developed as part of this project provides current regulation from the battery to the electrolyzer [carbon dioxide generator]. The unit design is based on Linear Technology model LTC3780 Buck-Boost Controller, configured as a constant current source. The circuitry provides for efficient power conversion from battery to load while operating over a wide range of input voltages and load impedances. Presently the efficiency of either controller is estimated at approximately 90%. For energy efficient systems this could be increased by careful selection of certain components. 
     The primary source of energy contemplated is solar energy which is collected during the daytime and stored into a conventional commercially-available rechargeable battery. Surplus solar energy is dumped when the battery is fully charged. If adequate solar energy is not available, the load will extract energy mainly from the battery and progressively go dormant [the load current decreases] to protect the battery from deep discharge which would result in reduced life. The stability of the system will therefore depend on levels of insolation, battery capacity, and load demand. 
     During the months of interest for carbon dioxide use, and therefore generation [generally late Spring to early Fall] daytime exceeds 10 hours, insolation is high, and the conditions are optimum for the system. In the event of continuous cloud coverage for up to two days, the system is de-rated only producing partial carbon dioxide output. A daily operating duration of the generator of 10-12 hours is anticipated. 
     The generation rate can be selected manually by operation of a rotary switch at varying discrete values of 0, 12, 18, 24, and 30 L./hour. Once the rate is set, generation of carbon dioxide is quasi-instantaneous. The rates, however, can be changed at will. 
     During operation, toroidal briquet is dissolved and the saturated toroidal briquet solution is decomposed into carbon dioxide and hydrogen. The carbon dioxide gas evolves through the apertures in the inner wall [central pipe] and is released through the discharge vent located at the approximate center of the lid. The lid also can hold means to scrub the gas phase and/or means to hold a secondary releaser that will continuously feed a pheromone, such as octenol, into the exhaust stream as may be necessary or desired to attract insects. 
     The foregoing has outlined some of the more pertinent objects of the generating and dispensing device. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the generating and dispensing device. Many other beneficial results can be attained by applying the disclosed generating and dispensing device in a different manner or by modifying the generating and dispensing device within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the generating and dispensing device may be had by referring to the summary of the generating and dispensing device and the detailed description of the preferred embodiment in addition to the scope of the generating and dispensing device defined by the claims taken in conjunction with the accompanying drawings. 
     SUMMARY 
     The above-noted problems, among others, are overcome by the generating and dispensing device. Briefly stated, the generating and dispensing device contemplates a sealed container with an easily removable lid which, when initialized, begins generating carbon dioxide at a pre-determined rate without intervention. The container has an upstanding inner cylindrical wall extending upward from the floor defining a first space outside the upstanding inner cylindrical wall and a second space within the upstanding inner cylindrical wall. 
     The lid has a hollowed shaft extending downward which is adapted to seat into the second space defined within the upstanding inner cylindrical wall. Attached to the lid and in the hollow space inside the shaft is a carbon dioxide generator. One or more OA toroidal briquets are placed in the first space of the container. Water is dispensed into the first space such that the water covers the top of the bottom OA toroidal briquet. 
     Then the shaft, with carbon dioxide generator attached to the lid, is set into the second space and the lid secured to the container. At least two conductive rods are attached to the carbon dioxide generator and extend up and past the top of the lid. Current from outside is applied to the rods. Carbon dioxide gases are thereby generated and directed from the container through a discharge vent in the lid above the shaft space and is captured for desired use. 
     The foregoing has outlined the more pertinent and important features of the generating and dispensing device in order that the detailed description that follows may be better understood so the present contributions to the art may be more fully appreciated. Additional features of the generating and dispensing device will be described hereinafter which form the subject of the claims. It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures and methods for carrying out the same purposes of the generating and dispensing device. It also should be realized by those skilled in the art that such equivalent constructions and methods do not depart from the spirit and scope of the generating and dispensing device as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature and objects of the generating and dispensing device, reference should be had to the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is cross-section view of the generating and dispensing device in operational configuration. 
         FIG. 2  is an exploded view of the generating and dispensing device. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings in detail and in particular to  FIGS. 1 and 2 , reference character  10  generally designates a carbon dioxide generation and dispensing device constructed in accordance with a preferred embodiment thereof. The device  10  has a container  21  with a floor  25 , an upstanding outer wall  23 , and an upstanding inner cylindrical wall  33  extending up from said floor  25  to a point below the top of the upstanding outer wall  23  referenced here as plane-K. A hollow first space  24  is defined between the upstanding outer wall  23  and the upstanding inner cylindrical wall  33  and a hollow second space  34  is defined within and inside of the inner cylindrical wall  33 . 
     The outer diameter of the first space  24  is referenced herein as D or diameter-D and its inner diameter is referenced herein as E or diameter-E. The inner diameter of this first space  24 , diameter-E, is also equal to the outer diameter of the upstanding inner cylindrical wall  33 . 
     A plurality of apertures  37  on the inner cylindrical wall  33 , near to the floor  25 , permit the free flow of matter to be described below. 
     A lid  11  securely attaches to, and covers, the container  21 . A conventional gasket or seal  51  is on the perimeter of the upstanding outer wall  23  providing a sealing component between the upstanding outer wall  23  and the lid  11 . The lid  11  is secured to the container  21  by fastening means between the two. As illustrated the fastening means comprise a first externally threaded fastening component  29  connected to, and extending above, the upstanding outer wall  23  and a cooperating second internally threaded component  16 . 
     As illustrated in  FIG. 2 , there are a plurality of externally threaded fastening components  29  around the upstanding outer wall  23 . Additionally, there are a plurality of corresponding apertures  19  on the lid  11  which register with, and fit onto, each of the externally threaded fastening components  29 . The seal  51  also has a plurality of corresponding apertures  59  which are in alignment with the corresponding apertures  19  on the lid  11  and with externally threaded fastening components  29 . As illustrated here, the internally threaded components  16  are conventional wing-nuts. This configuration facilitates securing the lid  11  to the container  21  and further facilitates its removal from the container  21  when, and as, necessary. 
     A hollow cylindrical shaft  13  extends downward from the bottom surface of the lid  11  which, when inserted into the second space, will extend to a point above the floor  25 . The outer diameter of the cylindrical shaft  13 , referenced herein as A or diameter-A, is less than the diameter of the second space  34 , referenced herein as B or diameter-B, thereby permitting the cylindrical shaft  13  to ride into the second space  34 . Diameter-B also equals the inner diameter of the inner cylindrical wall  33 . 
     Cylindrical shaft  13  is provided with a port  18  to equalize the internal pressure withing the device  10 . One or more such ports  18  may be located anywhere on the cylindrical shaft  13 . To facilitate the pressure equalization process, however, it is best that such ports  18  be above the top of the inner cylindrical wall  33 , plane K. 
     A hollow shaft space  14  is defined within the cylindrical shaft  13 . The shaft space  14  has a diameter referenced as G or diameter-G which also is the inner diameter of the cylindrical shaft  13 . 
     The lid  11  had a discharge vent  17  for directing the release and dispensing of pre-determined amounts of the carbon dioxide gas being generated within the device  10 . The discharge vent  17  is in communication with the shaft space  14 . As illustrated, the discharge vent  17  is relatively centrally located on the lid  11 , however, it may be located anywhere on the lid provided the discharge vent  17  remains in communication with the shaft space  14  such that gases generated within the device  10  are directed to and intended to be released only through the discharge vent  17 . 
     Typically an external hose or conduit  53  is removably attached to the discharge vent  17  to thereby convey the releasing gases to a desired destination. The lid  11  also has a pressure relief valve  15  which will permit generated gases within the device  10  to escape should the pressure within reach a pre-determined level. 
     The container  21  somewhat resembles an angel-food-cake pan or a bundt-cake pan. The inner cylindrical wall  33  is generally centrally located and rises upward from the floor  25 . An toroidal briquet  60 , with its donut-like shape, fits around the inner cylindrical wall  33  and, being the first toroidal briquet  60  placed therein, will rest on the floor  25  in the first space  24 . 
       FIG. 1  illustrates four toroidal briquets  60  stacked into the first space  24 . A carbon dioxide generator  41  [electrolyzer] with its generator-housing component  40  seats into the second space  34  such that the bottom of the generator  41  generally should not be touching the floor  25 . The bottom plane of the generator  41  is reference character J. The generator  41  should generally be slightly above the floor  25 . It may, however, touch the floor  25 , but it is preferred that it not to thereby allow the OA, when in solution, to freely flow underneath the generator  41 . 
     The generator-housing component  40  holding the generator  41  comprises a guide plate  45  having a plurality of apertures  47  to permit generated gases to pass therethrough and up and out the discharge vent  17 . The diameter of the guide plate is referenced herein as H or diameter-H and diameter-G [diameter of the shaft space  14 ] is greater than diameter-H. 
     At least two retaining rods  42 A,  42 B are affixed to the guide plate  45  with ends of the retaining rods  42 A,  42 B extending above and below the guide plate  45 . The retaining rods  42 A,  42 B have external threading and are secured to the guide plate  45  by any suitable fastening components such as, but not limited to, nuts  46  with internal threading compatible with, and to, the external threading of the retaining rods  42 A,  42 B. 
     The upper ends of the retaining rods  42 A,  42 B register with apertures  12 A,  12 B on the lid  11  and pass through and extend above and beyond the lid  11 . The retaining rods  42 A,  42 B must be produced using a conductive material for reasons to be explained below. 
     As illustrated, the generator  41  is attached to the retaining rods  42 A,  42 B. The guide plate  45  is attached to the retaining rods  42 A,  42 B at a point above the generator  41 . The guide plate  45  is firmly secured in position by use of a nut  46  above the guide plate  45  and a nut  46  below the guide plate  45 . The guide plate  45 , with its diameter-H slightly smaller than the shaft space  14  diameter-G, eases and guides the extraction and insertion process of the generator-housing component  40  onto the lid  11 . 
     Before this generator-housing component  40  is set into the lid  11  by inserting the retaining rods  42 A,  42 B through the respective lid apertures  12 A,  12 B, one nut  46  is threaded onto each retaining rod  42 A,  42 B and height-adjusted such that the bottom of the generator  41 , when the lid  11  with generator-housing component  40  is set onto the container  21 , does not contact the floor  25  and rests at approximately plane-J. When this height-adjustment is completed the generator-housing component  40  is firmly secured to the lid  11  first by placing a sealing ring  48  [such as, but not limited to, a rubber or other suitable washer] against the lid  11  followed by threading a nut on each of the retaining rods  42 A,  42 B extending above the lid  11 . The sealing rings  48  will prevent gases generated within from escaping at that connection. 
     Several such lid-to-generator attachments should be pre-made so that a user need only remove the lid structure [lid  11  with generator  41  attached thereto as described above] of a processing unit and replace it with another lid structure. 
     This configuration makes replacing a worn or defective generator  41  an easy operation requiring little or no skill. The user merely removes the external hose  53  and unfastens the wing nuts  16  which secure the lid  11  to the container  21 . The lid  11 , with attached generator-housing component  40  and generator  41  attached, are removed with the lid. A previously pre-made lid-to-generator attachment is placed into the down the second space  34  and easily guided into place. No adjustments will be necessary as all such pre-made lid-to-generator attachments have been pre-made to approximately equal specifications. 
       FIG. 1  illustrates four toroidal briquets  60  inside the first space  24 . Before the lid  11 , with generator  41  attached, is secured to the container  21 , water is placed into the first space  24  approximately up to the top surface of the generator  41  [illustrated here as the Water Level]. The lid  11  is then secured to the container  21  and the external hose  53  attached to the discharge vent  17 . 
     In the event excess water is placed into the container  21 , a discharge valve  27  on the bottom of the container  21 , in communication with the second space  34 , permits the user to easily discard any unwanted water by turning the discharge valve  27  to an open position, discharging water until the amount desired is left remaining, and turning the discharge valve  27  to the closed position. Similarly, use of the discharge valve  27  after carbon dioxide generation has completed, facilitates removal of any remaining aqueous OA solution from the container  21 . 
     The toroidal briquet  60  is donut-like with a hole  63  in the approximate center. The diameter of the hole  63  is referenced as C or diameter-C which also is equal to the inner diameter of the toroidal briquet  60 . The outer diameter of the toroidal briquet  60  is referenced as F or diameter-F. This outer diameter, diameter-F, is less than the outer diameter of the first space  24 , diameter-D and the diameter of the central hole  63  of the toroidal briquet  60 , diameter-C, is greater than the inner diameter of the first space  24 , diameter-E. 
     After one or more toroidal briquets  60  are placed into the first space  24  and water dispensed up to the approximate top of the generator  41 , the lid  11  secured to the container  21 , and an external hose  53  attached to the discharge vent  17 , a current is then applied to the retaining rods  42 A,  42 B to begin the generation and capture process. 
     Though wing nuts  16  and common internally threaded nuts  46  have been described with particularity herein as fastening components, it should be understood that any fastening component, suitable for the intended purpose, will suffice. 
     Additionally, the diameters disclosed herein are such that a relatively loose-fit is made between the outer diameter [diameter-A] of the shaft  13  and the diameter [diameter-B] of the second space  34  to preclude or best minimize escaping of any materials from the first space  24  into the second space  34  through any means other than as intended; i.e., through the plurality of apertures  37  on the upstanding inner cylindrical wall  33 . An equally loose-fit is envisioned between the guide plate  45  [with diameter-H] and the diameter of the shaft space  14  [diameter-G] for the purpose of facilitating and easing the insertion and removal of the generator-housing component  40  from the lid  11  and the shaft space  14 . 
     As described in the Background, which is incorporated herein by reference, the device, as part of the system, will continue to generate carbon dioxide, passing it through the device  10  as basically illustrated by the arrows in  FIG. 1 , for up to four weeks without need for human intervention. 
     The present disclosure includes that contained in the present claims as well as that of the foregoing description. Although this generating and dispensing device has been described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms has been made only by way of example and numerous changes in the details of construction and combination and arrangement of parts and method steps may be resorted to without departing from the spirit and scope of the generating and dispensing device. Accordingly, the scope of the generating and dispensing device should be determined not by the embodiment[s] illustrated, but by the appended claims and their legal equivalents. 
     Applicant has attempted to disclose all the embodiment[s] of the generating and dispensing device that could be reasonably foreseen. It must be understood, however, that there may be unforeseeable insubstantial modifications to generating and dispensing device that remain as equivalents and thereby falling within the scope of the generating and dispensing device.