US 3442788 A
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Description (OCR text may contain errors)
May 6, 1969 T, C. WQOTQN ET AL 3,442,788
OZONE GENERATOR Filed May 23, 1966 36 Fla.
INVENTOR. 779007,45 C. WOOTO/V,
WILL/AM EMA/VGOLD, BY WAARV L. DA VIS United States Patent O 3,442,788 OZONE GENERATOR Thomas C. Wooton, Arcadia, Calif. (5236 N. Peck Road,
El Monte, Calif. 91732), William F. Mangold, 1331 Mariana St., West Covina, Calif. 91790, and Warren L. Davis, 3026 Sullivan St., Rosemead, Calif. 91770 Filed May 23, 1966, Ser. No. 552,101 Int. Cl. B01k 1/00 U.S. Cl. 204--317 9 Claims This invention relates to an ozone generator and to improvements in component parts therefor.
Ozone generators of the type which utilize a glow discharge in a tube to convert atmospheric oxygen to ozone are widely known. The ozone itself is frequently utilized `for such purposes as retarding mildew and spoilage, and for reducing or eliminating odors.
Previously known ozone generators have been plagued by short life and inherent disintegration of their component parts. For example, it is not unusual for tubes gradually but definitely to lose their ozone-generating function. In many devices, the high-voltage current will are over when water accumulates, and the arc passes along a path which lies on the surface of material which may produce noxious gases, and which material is the insulator which insulates a high-voltage transformer from a metal case. Thus, a dangerous arcing and flash-over situation may result, and the unit may destroy itself.
It is an object of this invention to provide a long-lived ozone generator in which arcing-over is substantially eliminated and in which the tubes have longer lives.
An ozone generator according to this invention comprises a case having a bottom and a peripheral wall, a transformer, an insulator in the case, a ceramic dish mounted to the insulator and spaced by it from the case, and a pair of connectors mounted to said dish. A generator element is connected across the connectors and is supported by the dish, the dish including a continuons peripheral flange between the connectors and the peripheral wall of the case, and a continuous seal between the connectors and the bottom, whereby the length of path between the connectors and the case is lengthened by the flange.
According to a preferred but optional feature of the invention, the leads are provided between the transformer and the connectors, which leads pass through the dish, the transformer being located in the case.
According to still another preferred but optional feature of the invention, the generator comprises a borosilicate glass tube which has an internal cavity, this cavity being substantially evacuated but holding a quantity of inert gas at a reduced pressure. An electrode extends through the glass tube and is exposed to both the inside and outside thereof. The electrode makes a glass seal with the glass tube, the electrode being coated with chromium at the time when it is installed in the glass tube, and a layer of conductive material adherent to a portion to the outside of the glass tube in contact with that portion of the electrode which is exposed to the outside of the glass tube.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:
FIG. 1 is a cross-section taken in elevation of the presently preferred embodiment of the invention, certain elements being shown in schematic notation;
FIG. 2 is a top view of FIG. l;
FIG. 3 is an axial cross-section of a portion of FIG. l;
FIG. 4 is a fragmentary cross-section of a portion of FIG. 3;
FIG. 5 is a cutaway fragmentary side elevation of a device including the components of FIG. l;
FIG. 6 is a fragmentary side elevation of the saine; and
FIG. 7 is a top view of FIG. 6.
An ozone generator 10 according to the invention is shown in FIG. 1 which includes a case 11 having a bottom 12, a continuous peripheral wall 13, and an open top 14. As best seen in FIG. 6, the peripheral wall is provided -with an open window 15 in at least one side, and a lid 16 comprising an inverted perforated dish is pressed into the open top to make a frictional tit, thereby enclosing all of the elements, the perforations 17 in the lid enabling the ozone to escape from the case. The case therefore constitutes a continuous enclosure with all of the internal parts shielded from touch.
The case is conveniently primed internally with an epoxy coating 18 which may or may not be insulating, although an insulating layer is to be preferred. A transformer 19 of the gas tube type is placed in the bottom of the case and held in place by rivets 20 which pass through the bottom thereof and also serve to ground the case 21 of a gas tube transformer by connection with ground lead 22. A gas tube transformer has the property of high-leakage reactance so i-f there is a shortage across its output, there will be no damage to the transformer. The transformer is shown in schematic notation with its primary and secondary windings 23, 24, respectively, and a grounded core 25.
A capacitor 26 may be connected across the leads of the secondary winding, if desired, so as to alter the wave shape to increase the rate of ozone generation. At times, this capacitor is eliminated because it greatly steps up the rate of generation, sometimes to undesirable levels.
An insulator 27 is poured into the case so as to surround and pot the transformer and also the power leads Z8, 29 and the ground lead. These leads pass through a grommet 30 in a hole in the case and are connected to a power plug 31. Insulator 27 may conveniently be a mixture of 60% silica (Dixie clay) and 40% transformer tar, although other materials may be used instead.
Another layer of epoxy resin 32 is poured atop the insulator 27 and forms another portion of the insulator, this epoxy preferably being insulating material. It will be seen that high-voltage leads 33, 34 are potted by the insulator 27 and the resin 32.
A dish 35 is set into epoxy resin 32 while it is still soft. This dish has a continuous flange 36 and a bottom 37. When the epoxy hardens, the dish is firmly set in place. The dish includes a pair of standards 38, 39 which are spaced apart from each other, each of which includes a passage 40, 41 rising therethrough and passing a respective one of the high-voltage leads.
A connector 42, 43 is mounted such as by an epoxy layer 44, 45 to the top of each of the standards so as to make a fluid seal with the top of the standards. The connectors are metal plates which are attached to the high-voltage leads by rivets 46. It will now be seen that the entire high-voltage system is contained within the dish and the insulator, and that the high voltage is exposed only at the connectors. All other parts of this system are hermetically sealed. Atop the connectors is provided a plurality of spring clips 47.
Generator elements 50 comprising glow tubes are held in connective contact with respective connectors by the spring clips. It will now be seen that any possible arcing between the connectors and the case is impeded by being required to go down the surface of the standard, across the bottom of the dish, and up the peripheral ange. This so lengthens the path that arcing across is very unlikely. Should water collect in the dish, it will be found that arcing is possible through the water, but this simply results in speedy evaporation of the water and then the arcing will cease. There is no tendency for the current arc across the epoxy to break down the insulation or eate noxious gases as in prior art devices.
The dish is preferably made of ceramic materials such as VleX OI' pyro-Ceram.
The generator element comprises a glass tube 51 of )rosilicate glass which has inside and outside sur-faces. here is no lead migration in this type of glass which ruld lead to failure of the element. At one end, there -an electrode 52 that is exposed to both of said surfaces 1d makes a metalled glass seal therewith. A layer of inductive metal 53 is applied to the outside of the tube t as to be in contact with that end of the electrode which exposed to the outside surface. This material may be ich as platinum or other precious metal or nickel A loy. The electrode is best made from wire 54 as best lustrated in FIG. 4. This wire may conveniently be pure lngsten and it has been found that a better generator eletent is obtained if this tungsten is initially covered with layer 55 of chromium such as by sintering or plating, :cause this causes the wire to make a better seal with te glass. Once the tube is fired, it will be noted that the nromium on the exposed electrode surface inside the tbe will be driven off and a pure tungsten surface rerains which gives optium performance. The tube is es- :ntially evacuated, but is provided with an inert gas such s neon at a low pressure, approximately 18 mm. of merury. The diameter of wire 54 including its coating 55 is bout two mils, the thickness of the coating being exagerated in FIG. 4 for purposes of illustration. The coat- 1g is actually very thin. The wall thickness of the glass Jbe is preferably about 0.040 inch thick.
The generator elements are held by the clips, one clip eing in contact with the conductive material 53 and he other in contact with the glass. With the generator lements in places shown in FIG. l, lid 16 may be put n place and plug 31 connected to any desired source of rurrent such as 110 volts A.C. The transformer will ste-p lp the voltage, and the tubes will begin to glow, thereby ;enerating ozone. With the arrangement shown and with hese tubes, it will be found that very pure ozone is de- 'eloped with none of the nitrogen compounds frequently :aused by arcing in previously known ozone generators. hould water fall into the dish, arcing will sooner or later :ause it to be evaporated, but no miscellaneous com- )ounds will be developed because all arcing takes place )n the ceramic dish. Furthermore, arcing in general is )revented because of the lengthening of the surface path from the connectors to the case. The path is simply too ong for arcing to occur at the voltages customarily used. l`he stepped-up voltage will preferably be about 9000 .folts peak, although it could be higher, if desired.
This device can readily be manufactured of inexpensive parts and has a long service-free life. Much of the iervice-free benefits are derived from the particular gen- :rator element described herein, and the remainder from he path lengthening device, i.e. the dish, together with :he hermetic sealing off of all the electric components other than the connectors and the tubes themselves.
This invention is not to be limited by the embodiment shown in the drawings and described in the description which is given by way of illustration and not of limitation, but only in accordance with the scope of the appended claims.
1. An ozone generator comprising: a case having a bottom and peripheral wall; a transformer; an insulator in the case; a ceramic dish mounted to the insulation and spaced by it from the case; a pair of connec-tor-s mounted to said dish; a plurality of generator elements connected across said connectors each of said elements comprising a glass -tube having an internal cavity, said cavity being substantially evacuated but holding a quantity of inert gas at reduced pressure; -a conductive electrode extending through the glass tube and exposed to both the inside and outside thereof and in electrical communication with said connector and supported by the dish, the dish including -a continuous peripheral ange -between the connectors and the peripheral wall and a continuous seal between the connectors and the bottom, whereby the length of path between the connectors and the case is lengthened by the ange.
2. An ozone generator according to claim 1 in which leads are provided between said transformer and the connectors, which leads pass through the dish.
3. An ozone generator according to claim 1 in which a pair of standards rise from the bottom of the dish, each of said standards including a passage therethrough, and in which a lead passes through each of said passages to a respective connector and to the transformer, there being a uid seal between the standards and the leads.
4. An ozone generator according to claim 3 in which the transformer is contained within the case and covered by the insulator, and in which the case is supported atop the insulator and bonded thereto.
5. An ozone generator according to claim 4 in which each of the connectors comprises a buss bar.
6. An ozone generator according to claim 4 in which the elements for the generation of ozone comprise: a borosilicate glass tube having an internal cavity, said cavity being substantially evacuated but holding a quantity of inert gas at a reduced pressure; an electrode extending through the glass tube and exposed to both the inside and outside thereof, said electrode making a gas seal with the said glass tube, said electrode being coated with chromium when installed in said glass tube; and a layer of conductive material adherent to a portion of the outside of said glass tube and in contact with that portion of the electrode which is exposed -to the outside of said glass tube.
7. An ozone generator according to claim 6 in which the electrode is made of tungsten.
`8. An ozone generator according to claim 6 in which the layer of conductive material is made of platinum.
9. An ozone generator according to claim 6 in which the electrode is made of tungsten and the layer of conductive material is made of platinum.
References Cited UNITED STATES PATENTS 2,328,640 9/1943 Gage 204-317 2,808,374 lO/1957 Mueller et al. 204-317 ROBERT K. MIHALEK, Primary Examiner.