Abstract:
A high efficiency system for generating ozone includes a high frequency, high voltage AC power supply, preferably 20 khz at 100 watts. The ozone generator in the system comprising a pair of conductive plates mounted parallel and opposed to each other and a pair of dielectric films. Preferably fused quartz, adhesively secured to the opposed faces of the plates by a heat-conductive, electrically-conductive adhesive. The dielectric films are spaced from each other to define an air space for flow of an oxygen containing air stream there through. The air space encloses corona discharges created when power is delivered to the conductive plates, the corona discharges converting a portion of the oxygen flowing there through to ozone. Cooling means are also provided to the plates.

Description:
[0001]    This is a Continuation-in-Part of U.S. Patent Application 09/400,260 filed Sep. 21, 1999, now abandoned. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention is an ozone generator of the plate pair or stack-type plate design employing interleaved electrodes and dielectrics. In certain embodiments, it provides for turbulent oxygen flow and more controlled exposure of the entering oxygen to corona discharge.  
           [0003]    More particularly, the ozone generator uses a high wattage power source operating with a high frequency AC current, resulting in a lower reactance and the need for a smaller plate area than prior generators to produce the same or greater amounts of ozone.  
         BACKGROUND OF THE INVENTION  
         [0004]    Ozone (O 3 ), an allotropic form of oxygen and a powerful oxidant has increased importance as a disinfectant. Ozone effectively kills bacteria by breaking up their molecular structure, inhibits fungal growth, and inactivates many viruses, cysts, and spores. In addition, soaps, oils, chloramines and many other chemicals can be rendered environmentally safe by ozone treatment. Ozone combines with water to form hydroxyl radicals and peroxide, thus sterilizing the water. Because ozone is unstable, the ozone decomposes to oxygen leaving no residues to further eliminate. Ozone has a half-life of about 22 minutes in water at ambient temperatures. Consequently, for most cleaning/disinfecting operations, the cleaning residue after a short period of time contains only dead biological matter and water and, typically, requires no special disposal.  
           [0005]    In typical, conventional corona discharge type ozone generators, a very low percentage of the entering oxygen molecules actually encounter the corona discharge and is converted to ozone. The corona is produced only on one side of a dielectric. As a result, the ozone concentration in the discharged gas is low and the efficiency of the generator is low, particularly with regard to their size. Numerous different designs have been shown in the past for ozone generators. They all typically incorporate two electrodes separated by a dielectric (or insulator operating as a dielectric) with power being supplied to the electrodes through a transformer. Various different combinations of current and voltage are supplied; either AC or DC current have been used.  
           [0006]    Cragun, U.S. Pat. No. 2,113,913 is typical of a prior art electrical discharge device which produces a series of small discharges from a 5000 volt source. The unit is attached to a standard 110 volt, 60 cycle AC electrical source which is passed through a transformer to provide 5000 volts at a secondary terminal. A pair of electrically conductive plates  26  are separated by a pair of dielectrics  27  which are, in turn, separated by an electrically conductive grid  28 . The grid is attached to one terminal of the transformer such that the alternating potential impressed on the grid creates a discharge through the dielectric sheets, charging the plates at one extremity of the cycle. The plates, attached to ground, then discharge at the other extreme of the alternating current cycle. This produces numerous relatively small discharges converting oxygen located between the grid and plates to ozone.  
           [0007]    McBlain, U.S. Pat. No. 1,588,976, uses flexible conductors surrounded by an insulator which acts as a dielectric. The insulators may have ridges formed in their surface so that air can flow between alternating rolled or coiled insulated conductors. Electrical current is supplied through typical primary and secondary coils, suggesting the use of a transformer. However, the power supplied to the electrodes (AC or DC) and the ozone output capacity is not indicated.  
           [0008]    U.S. Pat. No. 4,062,748 to Imris shows another version of an ozone generator which uses alternating current with a minimum voltage of at least about 20,000 volts to start the corona discharge.  
           [0009]    Rice, U.S. Pat. No. 3,607,709 operates at less then ½ amp and 2000 to 4000 volts. Schaefer, U.S. Pat. No. 3,801,791 operates at 5000 to 15,000 volts 60 cps.  
           [0010]    Consequently, most ozone generators are limited to use in stationary industrial applications because of their large size and energy requirements. It is particularly desirable in mobile cleaning and disinfecting apparatus using ozone generators that the ozone generator be of compact size and as efficient as possible.  
         SUMMARY OF THE INVENTION  
         [0011]    This invention is a small size, high voltage, high efficiency ozone generator. A preferred embodiment comprises a) an enclosure including an entry chamber for receiving feed gas, such as air from a dryer, an oxygen concentrator on oxygen supply such as from a liquid oxygen source, or other enhanced oxygen feed sources b) one or more ozone generating cells comprising interleaved electrodes and dielectrics with passageways between the dielectrics for receiving gas from the entry chamber and converting the oxygen therein to ozone, c) an alternating voltage generator connected to the electrodes so as to create corona discharges between adjacent dielectrics, and d) an exit chamber at the other end of enclosure for receiving the ozone containing gas.  
           [0012]    A first typical ozone generating cell includes a first electrode, a second electrode, and first and second dielectrics. The first electrode includes a top face. The first dielectric includes a top and bottom face. The bottom face is opposed to the top face of the first electrode and separated therefrom so as to form a first passageway. The second electrode includes a bottom face opposed to the top face of the first dielectric and separated therefrom so as to form a second passageway. The received gas flows through the passageways. The top face of the first electrode may include a plurality of crests and troughs relative to the bottom face of the dielectric oriented across the flow of received gas through the first passageway. The bottom face of the second electrode may also include a plurality of crests and troughs relative to the top face of the dielectric and mirroring said crests and troughs of the top face of the first electrodes. The passageways between the crests and the dielectric will typically have a uniform gap or spacing.  
           [0013]    A second ozone generating cell comprises two opposed electrodes with first and second dielectric layers adhesively attached respectively to the opposed faces of the electrodes. The unattached faces of the first and second dielectric films are spaced apart and provide a flow space for feed oxygen to be exposed to a corona discharge emanating from the dielectric films.  
           [0014]    When powered, each dielectric provides a plurality of points of corona discharges on its unattached sides. The received gas must flow through substantially a continuous curtain of corona discharge. The turbulent flow is also created by the device construction, an increased gas flow rate and turbulence resulting from the corona heating of the feed gas in contact with the cooler dielectric films This cell design also eliminates the requirements for a corrosion resistant construction materials, such as stainless steel heat sink surfaces for corrosion resistance against nitric acid by -products created when air is used as a feed gas for ozone generators. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a diagram of a first embodiment of an ozone generating device including features of the invention.  
         [0016]    [0016]FIG. 2 is a partial perspective view of an ozone generating cell of the embodiment of FIG. 1.  
         [0017]    [0017]FIG. 3 is a partial vertical cross-sectional view of the ozone generator of FIG. 1.  
         [0018]    [0018]FIG. 4 is a partial vertical cross-sectional view of a second embodiment incorporating features of the invention.  
         [0019]    [0019]FIG. 5 is a partial vertical cross-sectional view of a third embodiment incorporating features of the invention.  
         [0020]    [0020]FIG. 6 is a top schematic diagram of a typical assembly including a single cell ozone generator incorporating features of the invention.  
         [0021]    [0021]FIG. 7 is a top cutaway view through the ozone generator portion of FIG. 6 showing the heat dissipation fins and gas inlet and outlet.  
         [0022]    [0022]FIG. 8 is an enlarged cutaway view of the circled portion of FIG. 7.  
         [0023]    [0023]FIG. 9 is a graph showing the relationship between Reactance and Frequency for a preferred embodiment.  
         [0024]    [0024]FIG. 10 is a graph showing the continuous relationship between RMS current and frequency in a preferred embodiment.  
         [0025]    [0025]FIG. 11 is a graph showing the relationship between voltage at constant current and frequency for a preferred embodiment.  
         [0026]    [0026]FIG. 12 is a graph showing the relationship between power density/square inch and voltage for a preferred embodiment.  
         [0027]    [0027]FIG. 13 is a graph showing the percentage of ozone in an exiting gas stream for a preferred embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    [0028]FIG. 1 is a diagram of an ozone generating device  80  including an enclosure  81  containing a first embodiment  10 A of the ozone generator  10  of the invention. Gas, including oxygen, such as air  98  from a dryer, an oxygen concentrator, another oxygen source or an oxygen enriched stream is received by propelling means, such as pump P, and propelled into an entry manifold of chamber  83  at one end  82  of enclosure  81 . Entering air  98  flows through ozone generator  10 A, where the oxygen gas is converted to ozone. The gas including ozone  99  enters exit manifold or chamber  85  at the other end  84  of enclosure  81  and exits through exit orifice  87 .  
         [0029]    Ozone generator  10 A includes a plurality of ozone generating cells including a plurality of high potential electrodes, such as first electrodes  20 , connected to an alternating resonant mode high voltage source  95 , a plurality of earth or ground electrodes, such as second electrodes  40 , connected to ground and a plurality of dielectrics  30 , a dielectric  30  being disposed between adjacent first electrodes  20  and second electrodes  40 . Electrodes  20 ,  40  and dielectrics  30  are all mounted interleaved in spaced relationship with their faces opposed. In this manner, first electrodes  20  and second electrodes  40  are electrically connected such that alternating high voltage electrical potentials exist between them.  
         [0030]    The walls of enclosure  81  are sometimes used as the two outer-most second electrodes  40 . Enclosure  81  is cooled in a manner known in the art.  
         [0031]    [0031]FIG. 2 shows a partial perspective view of an embodiment of an ozone generating cell of the ozone generator  10 A of FIG. 1. FIG. 3 is a partial vertical cross-sectional view of FIG. 1.  
         [0032]    Ozone generator  10 A generally includes a first electrode  20 ; a first dielectric  30  and a second electrodes  40 . First electrode  20  includes a first end  21 , a second end  22 , an entry side  23  an exit side  24 , bottom face  25 , and a top face  26 . Preferably, first electrode  20  is a corrugated plate such that its top and bottom faces  26 ,  25  include a plurality of crests and troughs traversing between its first and second ends  21 ,  22 . One end or both ends  21 ,  22  are supported, such as by enclosure  81  and/or by non-conducting spacers.  
         [0033]    First dielectric  30  includes a first end  31 , a second end  32 , first side  33 , a bottom face  35 , and a top face  36 . Bottom face  35  is opposed to top face  26  of first electrode  20  and separated therefrom so as to form a passageway  90 , such as first passageway  90 A, for flow of air  98 . Dielectric  30  may be made of suitable dielectric materials, such as glass or ceramic, with ceramic being preferred. Ceramic is preferred because it well withstands the temperatures produced, yet does not readily break if subjected to shock or if it is rapidly cooled, as happens in some usage environments of generator  10 A.  
         [0034]    Second electrode  40  is a corrugated plate and includes a first end  41 , a second end  42 , an entry side  43 , an exit side  44 , a bottom face  45 , and a top face  46 . Bottom face  45  is opposed to top face  36  of first dielectric  30  and separated therefrom so as to form a second passageway  90 B. Electrodes  20 ,  40  may be made out of various different suitable conductive materials as are well-known in the art, such as aluminum or stainless steel, with stainless steel being preferred because of its greater resistance to corrosion.  
         [0035]    Oxygen bearing gas  98  feed to the cell flows through first passageway  90 A from entry side  23  of first electrode  20  to exit side  24  of first electrode. The oxygen bearing gas  98  also flows through second passageway  90 B from entry side  43  of second electrode  40  to exit side  44  of second electrode  40 .  
         [0036]    Top face  26  of the first electrode  20  includes a plurality of crests  26 C and toughs traversing the flow of received gas  98  through first passageway  90 A. Bottom face  45  of the second electrode  40  includes a plurality of crests  45 C and troughs mirroring the crests and troughs of the top face  26  of the first electrode  20 . The gap G between each crest  26 C,  45 C and dielectric  30  is uniform.  
         [0037]    [0037]FIG. 3 shows a plurality of first electrodes  20 , dielectrics  30  and second electrodes  40  mounted in accordance with an embodiment of the invention. Entry oxygen-bearing gas  98  flows through passageways  90 A- 90 F. The crests and troughs of adjacent electrodes  20 ,  40  mirror those of the adjacent electrodes thus varying the height of passageways  90  relative to dielectrics  30  with the height being a minimum at gap G between each crest and dielectric  30 . Typical size of gap G is 1-3 mm. The resultant electric field strength varies from a maximum between mirrored crests to a minimum between mirrored troughs. Alternating voltage source  95  provides voltage to produce a discharge or corona between mirrored crests and interposed dielectric  30 . The wave form for producing the corona discharge is essentially an alternating high-frequency sine wave with a typical voltage range between  
         [0038]    [0038] 4000 - 
         [0039]    [0039] 10 , 000  volts and a typical frequency range being  
         [0040]    [0040] 10 - 
         [0041]    [0041] 30  Kilohertz. As a result, along the length of each gap G, each dielectric  30  has a series of discharge coronas almost continuously touching both bottom and top faces  35 ,  36  so as to form a curtain of corona. The voltage alternates at high frequency such that all entering gas  98  must pass through a fairly continuous curtain of corona at each gap G. In this manner, all of the oxygen molecules are exposed to corona for disassociating atomic oxygen. The wider areas of passageways  90  between the troughs and dielectrics  30  provide for turbulent flow of air  98  and provide dwell time for recombination of the disassociated oxygen atoms into ozone.  
         [0042]    The turbulent flow increases the ozone-forming dwell time within the generator. The back pressure resulting from the turbulent flow increases the pressure concentration of gas exposed turbulent flow increases the pressure concentration of gas exposed to the coronas.  
         [0043]    [0043]FIG. 4 is a partial vertical cross-sectional view of an alternate embodiment ozone generator  10 B, similar to generator  10 A except between adjacent electrodes  20 ,  40  there is only one passageway  90  because the interposed dielectric  30 B has a face in contact with the face of one of the electrodes  20 ,  40 . Thus, there is only one passageway  90  for each dielectric  30 B.  
         [0044]    [0044]FIG. 5 is a partial vertical cross-sectional view of a further alternate embodiment ozone generator  10 C, similar to  10 B except the electrodes of one set of electrodes, such as ground electrodes  40 C, are flat and have both their faces in contact with the adjacent interposed dielectrics  30 C.  
         [0045]    [0045]FIG. 6 is a schematic representation of an ozone generating assembly  100  incorporating a single cell ozone generator  110  embodiment incorporating features of the invention. In the embodiment shown  
         [0046]    [0046] 110  volt, 60 cycle AC power is feed to a power supply  112  which incorporates electronics and a transformer for providing the high voltage, high frequency power feed to a first plate  114  of the ozone generator. A suitable power supply is provided as the ET or ETI series electronic transformers by Plasma Technics, Inc. of Racine Wis. These units convert 110/120V or 220V, 50/60 hz input to a substantially sinusoidal 50 or 100 watt, 20 khz output (resonant mode) and are particularly designed for continuous duty corona discharge ozone generators. The circuits used in these power supplies are believed to be described in U.S. Pat. No. 5,313,145. A second plate  116  of the ozone generator  110  is connected to ground. The assembly also includes a cooling fan  120  to blow cooling air over the flutes  118  extending from the outer surface of the plates.  
         [0047]    As best shown in FIG. 7, and the enlarged view in FIG. 8 of the circled portion  135  of FIG. 7, both plates  114 ,  116  have flutes, fins or elongated projections  118  extending therefrom to allow dissipation of heat generated in the ozone generator  110  during operation. The inner face  122  of the first plate  114  faces the inner face  124  of the second plate  116 . In the figures, the inner faces  122 ,  124  have an exposed rectangular surface. However, various different shaped surfaces, including square, circular, oval, as well as numerous other two dimensional geometric shapes may be used. Mounted on each of the inner faces  122 ,  124 , using an electrically and thermally conductive, heat stable adhesive  126 , is a dielectric film  128 . These two dielectric films which are sized to approximately match the size of the inner faces  122 ,  124  are separated by an air space  130 . The distance between the plates, ie the thickness of the air space, which constitutes an oxygen flow path, is maintained by a gasket  132  which surrounds the air space on all sides (i.e. four sides in the case of a square or rectangular inner face  122 ,  120 ). A secondary seal of liquid silicone adhesive (not shown) is applied to the outer sealing edge between  116 ,  132  and  114 ,  132 . to reduce corona leakage into the air during operation. Air, or an oxygen enriched gas stream, is feed through inlet tube  134  into the air space  130  where it is exposed to a corona created between the dielectric films by application of high frequency, high voltage alternating current to the first plate  112 . The corona causes a portion of the oxygen in the feed stream to be converted to ozone. The ozone containing stream then exits the ozone generator through outlet tube  136 .  
         [0048]    For all generators, there is a relationship between the plate size and the frequency of electrical current provision. The lower the frequency, the lower (or the larger the Xc) the reactance through a dielectric is. The higher the frequency, the smaller the reactance is. Further, the power density is a function of watts delivered per square inch of plate inner face  122  surface area. Values for frequency vs. reactance for a preferred fused quartz dielectric are listed in Table I and shown in FIG. 9  
                                         TABLE I                                   Frequency   Reactance in           in KHz   Ohms                                        1   5134030.5           2   2567015.3           3   1711343.5           4   1283507.6           5   1026806.1           6   855671.75           7   733432.93           8   641753.81           9   570447.83           10   513403.05           11   466730.05           12   427835.88           13   394925.42           14   366716.46           15   342268.7           16   320876.91           17   302001.79           18   285223.92           19   270212.13           20   256701.53           21   244477.64           22   233365.02           23   223218.72           24   213917.94           25   205361.22                      
 
         [0049]    Low reactance numbers at high frequency combine to give smaller area requirements for the plate(s) in a generator design. For example, using a constant power device (100 watts of power) at a given frequency (20 Khz), 5000 volts and 0.020 Amps can be provided. This also means that a reactive load of 250K ohms (Xc) can be driven.  
         [0050]    Without regard to dielectric spacing, required plate area will increase as frequency decreases. The formula for determining plate capacitance is: 
         C=(0.885×(dielectric constant)×cm 2 ×(number of plates)/dielectric spacing (cm). 
         [0051]    Using fused quartz as the dielectric (dielectric constant=3.78) the values listed in Table II and FIG. 10 are obtained.  
                                                         TABLE II                                   Frequency   Reactance   Power in   plate current           (KHz)   (OHMs)   (Watts)   amp/in 2                                          1   5134030.51   100   0.004413374           2   2567015.255   100   0.006241454           3   1711343.503   100   0.007644189           4   1283507.627   100   0.008826749           5   1026806.102   100   0.009868605           6   855671.7516   100   0.010810515           7   733432.93   100   0.011676691           8   641753.8137   100   0.012482908           9   570447.8344   100   0.013240123           10   513403.051   100   0.013956315           11   466730.0464   100   0.014637507           12   427835.8758   100   0.015288378           13   394925.4238   100   0.015912648           14   366716.465   100   0.016513335           14   366716.465   100   0.016513335           15   342268.7007   100   0.017092926           16   320876.9069   100   0.017653498           17   302001.7947   100   0.018196809           18   285223.9172   100   0.018724362           19   270212.1321   100   0.019237453           20   256701.5255   100   0.019737211           21   244477.6433   100   0.020224623           22   233365.0232   100   0.020700561           23   223218.7178   100   0.0211658           24   213917.9379   100   0.021621031           25   205361.2204   100   0.022066872                      
 
         [0052]    As a example, C=0.5 χ 3.14159 χ F χ Xc where F is the frequency in hz and X c  is reactance in is in mulliohms—see table I where X c  for 20 khz=256,70 1,525); for a preferred embodiment C=0.5 χ 3.1415926 χ 20000* χ 250,000)=3.1831E-11 or 31.8 Pico Farads of reactive load.  
         [0053]    The ideal size (area) for the plates is highly dependent on the properties of the dielectric and the pacing, between the plates and/or the dielectric film. Using 5000 volts, the ideal spacing (the air gap) determined to be 1 to 2 mm.  
                                                             TABLE III                                   Plate   power density           Power       Current   Area   in watts/       watts   voltage   amps   In 2     square inch                                100   5000   0.02   0.5   200           100   5000   0.02   1   100       100   5000   0.02   1.5   66.66667       100   5000   0.02   2   50       100   5000   0.02   2.5   40       100   5000   0.02   3   33.33333       100   5000   0.02   3.5   28.57143       100   5000   0.02   4   25       100   5000   0.02   4.5   22.22222   Preferred       100   5000   0.02   5   20   Operating       100   5000   0.02   5.5   18.18182   Conditions       100   5000   0.02   6   16.66667       100   5000   0.02   6.5   15.38462       100   5000   0.02   7   14.28571       100   4900   0.02   7.5   13.33333       100   4800   0.02   8   12.5       100   4700   0.02   8.5   11.76471       100   4600   0.02   9   11.11111       100   4500   0.02   9.5   10.52632       100   4400   0.02   10   10       100   4300   0.02   10.5   9.52381       100   4200   0.02   11   9.090909       100   4100   0.02   11.5   8.695652       100   4000   0.02   12   8.333333       100   3900   0.02   12.5   8                  
 
         [0054]    This data shows that the required plate area is reduced to ⅕ by increasing the frequency from 1 to 25 Khz while maintaining the input power fixed. The power remains constant over the area giving reduced voltage or increased current from ideal as stated above (see Table III and FIGS. 11 and 12). The relationship between heat and power are a function of power density (outpower) on the plates in watts per square inch (FIG. 12). The production of ozone drops off substantially if the oxygen fed to the generator is heated above 130 deg F. The trade off between power density, plate area, dielectric, spacing and operating temperature is critical to obtain optimum operation. However, it has been determined that an optimal arrangement, using 5 layers of materials between heat sink/conductor plates is.  
         [0055]    Layer 1—an electrically and thermally conductive adhesive  
         [0056]    Layer 2—a substantially flat 0.02-0.035 layer of fused quartz  
         [0057]    Layer 3—a silicone rubber or expanded teflon gasket 0.03125 thick to provide an air gap  
         [0058]    Layer 4—a second layer of 0.02-.0.035 layer of fused quartz.  
         [0059]    Layer 5—a second layer of electrical and thermally conductive epoxy (see FIGS.  7 - 8 )  
         [0060]    The plates can be composed of various conductive materials such as aluminum, stainless steel, or copper. However, a preferred material for this embodiment is 6063 T5 aluminum because of its combination of electrical conductivity and heat conduction. Also various dielectric materials can be used but the preferred material is fused quartz which has at least about 99% silcon dioxide content and a minimal dipole moment internal heating effect. The adhesive must be a electronically and thermally conductive and resistant to heat so that it will hold the dielectric in place, maintaining the air space. The preferred adhesive is a conductive epoxy, such as Master Bond EP76M. A silicone rubber gasket, such as red, 60 durometer silicone gasket provided by, International Belt and Rubber or a Teflon Gasket (Inertech UHF expanded PTFE) preferrably about {fraction (1/32)}″ thick, provides the necessary seal of the air space, resists deformation from heat and is resistant to the ozone levels generated in the device. The secondary liquid seal (not shown) is a GE Silicone II gel sealant.  
         [0061]    In a typical preferred embodiment the adhesive is about 0.002 to 0.003 inches thick. The dielectric film, is cut to a rectangular shape about 4 inches by about 1.75 and about 0.015 to about 0.035 in. thick, preferably 0.025-0.035 in. thick. The air space is from about 0.020 to about 0.035 in. thick with the preferred thickness being 0.031 inches. The gasket is also rectangular in shape and sized to both overlap the dielectric film by from about 0.1875 to about 0.3 inches and be wider than the dielectric film by about 0.20-0.250 inches on each side A suitable gasket for the above described dielectric film has outer dimensions of about 4.45 inches by 2.5 inches and a central open space of about 3.4 inches by 1.375 inches, thus providing a 0.145 in 3  space between two dielectrics, each having a total exposed surface area of about 4.675 in 2 .  
         [0062]    The invention comprises a high frequency design. The objective is to obtain the highest possible energy density without raising the operating temperature above a level where heat will began to destroy the ozone product as fast as it is created. A further alternative is to reduce the surface temperature of the plates by adding more exotic cooling methods such as liquid cooling, PelTier junctions, refrigeration, phase change liquids, etc.  
         [0063]    Taking into consideration the economics of ozone generation the limiting factor is the cost of construction, materials, power delivery and space efficiency versus the pounds of ozone generated/time. A preferred construction comprises a unit measuring 6″″×8″×4″ deep,  
         [0064]    Uses only room air provided by an internal fan  
         [0065]    Produces ozone at 4.8 KWh per pound of ozone  
         [0066]    Produces 0.62 pounds of ozone (309 cubic inches per pound of ozone) per day at about a cost of about $400.00 per pound of Ozone  
         [0067]    Table IV lists quantities of ozone generated from such a device. These quantities are shown graphically in FIG. 13. The pounds per day of ozone generated (1 bs/day ozone) is given by: 
         (ft 3 /hr 0 O 2 )χ(ozone concentration %)χdensity of O 3 χm 3 /ft 3 24=0.50225793 
         [0068]    [0068]                                                         TABLE IV                                       Ozone   correction               Oxygen   production   factor for           flow in   (% by   7 psi   Pounds per           SCFH   weight)   pressure   day at 72 F.                                        1   3.5   4.4975   0.087531245           2   3.2   4.112   0.160057133           3   3.1   3.9835   0.232583021           4   2.97   3.81645   0.297106053           5   2.891   3.714935   0.36150404           6   2.75   3.53375   0.412647296           7   2.653   3.409105   0.464440783           8   2.512   3.22792   0.502579397           9   2.317   2.977345   0.521511155           10   2.173   2.792305   0.543443984           11   2.034   2.61369   0.559549733           12   1.954   2.51089   0.58640932           13   1.821   2.339985   0.592036329           14   1.761   2.262885   0.616570086           15   1.717   2.206345   0.644104915           16   1.658   2.13053   0.663436815                        
         [0069]    From the foregoing description, it is seen that the present invention provides an extremely compact and efficient ozone generator.  
         [0070]    Although particular embodiments of the invention have been illustrated and described, various changes may be made in the form, composition, construction, and arrangement of the parts herein without sacrificing any of the advantages. Therefore, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense, and it is intended to cover in the appended claims such modifications as come within the true spirit and scope of the invention.