U.S. patent number 3,884,819 [Application Number 05/498,845] was granted by the patent office on 1975-05-20 for gas cooling and drying system for corona discharge ozone generating unit.
This patent grant is currently assigned to Ozone Incorporated. Invention is credited to Ronald A. Schultz, Robert I. Tenney.
United States Patent |
3,884,819 |
Schultz , et al. |
May 20, 1975 |
Gas cooling and drying system for corona discharge ozone generating
unit
Abstract
A unique combination of one and preferably a pair of gas drying
units for drying oxygen containing gas to be ozonized and a corona
discharge ozone generating unit is provided by a vortex tube unit
having an inlet for receiving dried air to be ozonized, a cool air
outlet carrying the slow moving molecules of the gas to the inlet
of the ozone generating unit and a warm air outlet connected
through passageways extending to openings in the drying units for
circulating warm air for drying saturated gas drying units. Where
two drying units are provided, the air to be dried and ozonized is
preferably alternately automatically fed to the inputs of the two
drying units, and the warm air outlet of the vortex tube unit is
alternately fed through the air drying unit so the drying unit
which at a given instant is not receiving air to be dried is itself
being dried by warm de-moisturizing air.
Inventors: |
Schultz; Ronald A. (Berkeley,
IL), Tenney; Robert I. (Deerfield, IL) |
Assignee: |
Ozone Incorporated (Deerfield,
IL)
|
Family
ID: |
23982744 |
Appl.
No.: |
05/498,845 |
Filed: |
August 19, 1974 |
Current U.S.
Class: |
422/186.09;
422/186.11; 62/5 |
Current CPC
Class: |
C01B
13/11 (20130101); B01D 53/26 (20130101); C01B
2201/66 (20130101); C01B 2201/70 (20130101); C01B
2201/90 (20130101) |
Current International
Class: |
C01B
13/11 (20060101); B01D 53/26 (20060101); C01b
013/12 (); F25b 009/02 () |
Field of
Search: |
;55/17 ;62/5
;250/533,541,536-538 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mack; John H.
Assistant Examiner: Weisstuch; Aaron
Attorney, Agent or Firm: Wallenstein, Spangenberg, Hattis
& Strampel
Claims
We claim:
1. In combination, a corona discharge ozone generating unit; means
for cooling the corona discharge ozone generating unit comprising a
vortex tube unit for receiving gas to be ozonized at a first inlet
and separating the high energy gas molecules from the low energy
gas molecules therein and delivering the resultant relatively cool
gas molecules to a cool gas outlet therof and the relatively warm
gas molecules to a warm gas outlet thereof; a main inlet for an
oxygen containing gas to be ozonized; a drying unit providing for
the flow in one direction or the other therethrough of gas to be
dried and ozonized and including means for absorbing moisture from
the gas flowing therethrough which must be periodically dried with
warm gas, said gas drying unit having a first inlet at one end into
which oxygen containing gas to be dried is to pass into the unit,
an outlet for a de-moisturizing gas from which outlet drying gas
passes from the unit, and an opening from whcih dried oxygen
containing gas can exit from the unit or drying warm gas can enter
the unit; conduit means forming a first passageway interconnecting
said main inlet and said first inlet of said drying unit; valve
means in said first passageway for selectively opening and closing
said first passageway; conduit means forming a second passageway
extending between said outlet for de-moisturizing gas of said
drying unit and a discharge point therefor; second valve means for
said second passageway for selectively opening or closing the same;
conduit means forming a third passageway extending between said
opening in said drying unit from which dried oxygen containing gas
can exit and said inlet of said vortex tube unit; third valve means
for said third passageways for closing off the associated
passageway leading to said inlet of said vortex tube unit when the
opening of the associated drying unit acts as an entryway for
de-moisturizing gas and for opening the same when the opening of
the associated drying unit is to act as an exitway for dried oxygen
containing gas; conduit means forming a fourth passageway extending
from the warm air outlet of said vortex tube unit to a point of
said third passageway on the side of said third valve means nearest
said opening in said drying unit; foruth valve means for said
fourth passageway for closing off the associated passageway when
the opening in hte associated drying unit is to act as an exitway
for dried gas to be ozonized and for opening the associated
passageway when the opening of said drying unit acts as an entryway
for de-moisturizing gas; and conduit means extending between the
cool gas outlet of said vortex tube unit and the inlet to said
ozone generating unit for feeding sufficient quantities of cold gas
through said ozone generating unit to generate the required amount
of ozone and to cool the surfaces within said ozone generating unit
so that the temperature of the ozone produced does not reach an
elevated temperature at which ozone substantially dissociates.
2. An ozone generating system comprising a main inlet for an oxygen
containing gas to be ozonized, a first and a second drying unit
each providing for the flow in one direction or the other
therethrough of gas to be dried and including saturable means for
absorbing moisture from the gas flowing therethrough which
saturable means must be periodically dried with conduit means
forming a pair of passageways respectively connecting said main
inlet to inlets for gas to be ozonized of siad first and second
drying units; a first pair of valve means respectively for said
first pair of passageways for selectively opening one or the other
of said first pair of passageways; conduit means forming a second
pair of passageways respectively extending between outlets for
exiting de-moisturizing warm air therefrom of said first and second
drying units and a discharge point therefor; a second pair of valve
means respectively for said second pair of passageways for
selectively opening one or the other of said second pair of
passageways; a corona discharge ozone generating unit; and means
for cooling the corona discharge ozone generating unit and
supplying warm de-moisturizing air to said gas drying units
comprising a vortex tube unit for receiving air at a first inlet
and separating the high energy gas molecules from the low energy
gas molecules therein and delivering the resultant relatively cool
gas molecules to a cool gas outlet thereof and relatively warm gas
molecules to a warm gas outlet thereof; conduit means forming a
third pair of passageways respectively extending between openings
in said drying units and said inlet of said vortex tube unit, from
which dried oxygen containing gas exits or drying warm gas enters
the units; a thrid pair of valve means respectively for said third
pair of passageways each for closing off the associated passageways
leading to said inlet of said vortex tube unit when the opening of
the associated drying unit is to act as an entryway for
de-mositurizing gas and for opening the same when the opening of
the associated drying unit is to act as an exitway for dried oxygen
containing gas; conduit means forming a fourth pair of passageways
extending from the warm air outlet of said vortex tube unit
respectively to points of said third pair of passageways on the
side of said third valve means nearest said openings in said drying
units; a fourth pair of valve means respectively for said fourth
pair of passageways each for closing off the associated passageways
when the opening in the associated drying unit is to act as an
exitway for dried gases and for opening the associated passageway
when the opening of the associated drying unit acts as an entryway
for de-moisturizing gas; and conduit means extending between the
cold gas outlet of said vortex tube unit and the inlet to said
ozone generating unit for feeding sufficient quantities of cool gas
through said ozone generating unit to generate the required amount
of ozone and to cool the surfaces within said ozone generating unit
so that the temperature of the ozone produced does not reach the
elevated temperature at which ozone substantially dissociates.
3. The ozone generating system of claim 2 wherein there is provided
timer means for automatically periodically effecting the
alternately opening and closing of said first, second, third and
fourth pair of valve means so the oxygen containing gas to be
ozonized is alternately automatically fed to the inlet of said
drying units, said opening of the drying unit receiving oxygen gas
to be ozonized is connected to the inlet of the vortex tube unit,
said opening of the other drying unit is connected to the warm gas
outlet of said vortex tube unit, and said outlet for
de-moisturizing gas of the latter drying unit is coupled to said
discharge point.
4. The ozone generating system of claim 3 wherein said third and
fourth pair of valve means are one way valves operated by the
pressure differentials present in said third and fourth pairs of
passageways by the flow paths determined by said first pair of
valve menas.
5. In combination, a corona discharge ozone generating unit; means
for cooling the corona discharge ozone generating unit comprising a
vortex tube unit for receiving gas to be ozonized at a first inlet
and separating the high energy gas molecules from the low energy
gas molecules therein and delivering the resultant relatively cool
gas molecules to a cool gas outlet thereof and the relatively warm
gas molecules to a warm gas outlet thereof; a main inlet for an
oxygen containing gas to be ozonized; a drying unit providing for
the flow therethrough of gas to be dried and ozonized and including
means for absorbing moisture from the gas flowing therethrough
which must be periodically dried with gas, said gas drying unit
having inlet means at which oxygen containing gas to be dried and
warm de-moisturizing gas are to pass into the unit, outlet means
from which de-moisturizing gas passes from the unit and the dried
oxygen containing gas con exit from the unit; conduit means forming
passageway means interconnecting said main inlet and said inlet
means of said drying unit; valve means in said passageway means for
selectively opening and closing the same; conduit means forming
passageway means extending between said outlet means for
de-moisturizing gas and a discharge point therefor; valve means for
the last mentioned passageway means for selectively opening or
closing the same; conduit means forming passageway means extending
between said outlet means from which dried oxygen containing gas
can exit from the drying unit and said inlet of said vortex tube
unit; valve means for the last mentioned passageway means for
selectively opening and closing the same; conduit means forming a
passageway mean extending from the warm air outlet of said vortex
tube unit to said inlet means for de-moisturizing gas; valve means
for the last mentioned passageway means for selectively opening and
closing the same; and conduit means extending between the cool gas
outlet of said vortex tube unit and the inlet to said ozone
generating unit for feeding sufficient quantities of cold gas
through said ozone generating unit to generate the required amount
of ozone and to cool the surfaces within said ozone generating unit
so that the temperature of the ozone produced does not reach an
elevated temperature at which ozone substantially
disassociates.
6. An ozone generating system comprising a main inlet for an oxygen
containing gas to be ozonized, a first and a second drying unit
each providing for the flow of gas to be dried and including
saturable means for absorbing moisture from the gas flowing
therethrough which saturable means must be periodically dried with
a de-moisturizing gas; conduit means forming a first pair of
passageways respectively connecting said main inlet to respective
inlets for gas to be ozonized of said first and second drying
units; a first pair of valve means respectively for said first pair
of passageways for selectively opening one or the other of said
first pair of passageways; conduit means forming a second pair of
passageways respectively extending between outlets for exiting
de-moisturizing warm air from said first and second drying units
and a discharge point therefor; a second pair of valve means
respectively for said second pair of passageways for selectively
opening one or the other of said second pair of passageways; a
corona discharge ozone generating unit; and means for cooling the
corona discharge ozone generating unit and supplying warm
de-moisturizing air to said gas drying units comprising a vortex
tube unit for receiving air at a first inlet and separating the
high energy gas molecules from the low energy gas molecules therein
and delivering the resultant relatively cool gas molecules to a
cool gas outlet thereof and relatively warm gas molecules to a warm
gas outlet thereof, conduit means forming a third pair of
passageways respectively extending between openings in said drying
units and said inlet of said vortex tube unit, from which openings
dried oxygen containing gas can exit the drying units, a third pair
of valve means respectively for said third pair of passageways each
for selectively opening or closing the associated passageways,
conduit means forming a fourth pair of passageways interconnecting
respectively the warm air outlet of said vortex tube unit and
openings in said drying units; a fourth pair of valve means
respectively for said fourth pair of passageways each for
selectively opening and closing the associated passageways, and
conduit means extending between the cold gas outlet of said vortex
tube unit and the inlet to said ozone generating unit for feeding
sufficient quantities of cool gas through said ozone generating
unit to generate the required amount of ozone and to cool the
surfaces within said ozone generating unit so that the temperature
of the ozone produced does not reach the elevated temperature at
which ozone substantially dissociates.
7. The ozone generating system of claim 6 wherein there is provided
timer means for automatically periodically effecting the
alternately opening and closing of said first, second, third and
fourth pair of valve means so the oxygen containing gas to be
ozonized is alternately automatically fed to the inlet of said
drying units, said opening of the drying unit from which dried
oxygen gas to be ozonized passes is connected to the inlet of the
vortex tube unit, said opening of the other drying unit into which
de-moisturizing gas is to pass into the drying unit is connected to
the warm gas outlet of said vortex tube unit, and said outlet for
de-moisturizing gas of the latter drying unit is coupled to said
discharge point.
Description
BACKGROUND OF THE INVENTION
Ozone is produced by passing oxygen or a mixture of gases
containing oxygen, such as air, through the corona existing between
pairs of electrodes which are separated by an air gap and a
dielectric shield and which are connected to a high voltage source.
This corona evolves heat, only a fraction of which (about 34
kilocalories per gram mol) is required for the formation of ozone.
If the excess heat is not dissipated, the temperature of the
effluent gases, the electrodes, dielectric shield and housing is
elevated. This leads to decomposition of a portion of the ozone
which is approximately 100.degree.C breaks down almost as soon as
it is formed. The higher the temperature the more rapidly does the
ozone decompose. The heat may also cause the resistive properties
of the dielectric shields utilized to change so that they
perforate, causing short circuits within the electrode array.
In the past, a portion of the heat produced by the ozonation
process was dissipated by enlarging the electrode surface area in
respect to the length of the corona filled air gap. This creates
problems of warping with resulting short circuits. Others have
sought to cool the electrodes by passing a refrigerant such as
water or brine through and/or over them. Aqueous refrigerants
cannot be used within the corona area so are confined to use within
the electrode structure. This calls for enlarging the physical size
of the cooled electrode and requires that one side of the
electrical circuit be grounded, thereby preventing the use of
center tap grounded transformer windings to reduce the magnitude of
the voltages with respect to ground present in the equipment
involved.
The dielectric shield generally used between the electrodes of an
ozone generating unit is made of a glass or similar material which
can be readily cracked or punctured when excessive stresses are
applied thereto by hot spots or wide variations in temperature of
the air moving over different portions thereof. Cracking or
puncturing of the dielectric shield will destroy the insulating
qualities thereof and cause arcing and destruction thereof. Hot
spots can be caused by an unequal distribution of the electric
field due to variations in the spacing between the electrodes, and
wide extremes of temperature of the air moving over the dielectric
shield can be caused by uncontrolled air inlet temperatures and
ozonation. It may be that while it has been proposed to pre-cool
air to be ozonized in an ozone generating device, as for example
disclosed in U.S. Pat. No. 3,024,185 to Fleck, such pre-cooling has
not been commercially utilized to any significant extent because it
increases the possibility of undesired temperature ranges of the
air flowing over the dielectric shields. Thus, most commercial
ozone generating units utilize grounded water-cooled jackets
surrounding the outermost electrodes thereof which result in
expensive bulky equipment which in many cases does not adequately
cool portions of the ozone cooling generating unit remote from the
cooling jackets.
The air to be ozonized should be dry to prevent insulation
breakdown and to prevent the formation of nitric acid which might
corrode the electrodes. The air should also be free of oil and
other combustibles. It is common, therefore, to pass air to be
ozonized through filters and an air drying unit, which is generally
a unit containing a desiccant material which absorbs moisture. When
this desiccant material becomes saturated, it is necessary to dry
the same. In some cases, a pair of such drying units are utilized,
one of which is used at a given time for drying the air fed to the
ozone generating unit and the other of which may be dried by
passing warm air therethrough obtained by passing ambient air
through a heater and circulating the same through the drying unit
in any suitable way.
To summarize some of the deficiencies of prior ozone generating
systems, they were generally of relatively bulky construction and,
therefore, not particularly suitable for the manufacture of
portable ozone generating equipment, were relatively expensive to
manufacture, and in many cases were relatively unreliable due to
pitting or breaking of the dielectric shields used therein.
Moreover, they frequently required the presence of an operator to
check temperatures in the system and to watch the condition of the
air drying units so the operator could switch over from a saturated
drying unit to a previously dried drying unit to insure the feeding
of dry air to the ozone generating unit.
SUMMARY OF THE INVENTION
The present invention represents a substantial improvement over the
prior art by reducing the cost of the ozone generating equipment
and the size thereof and its dependence on the use of a circulating
coolant liquid so it can, where desired, be mounted on a portable
cart where it can be moved easily to point where its use is desired
and be placed into operation merely by connecting it to a source of
electric power and a source of air to be ozonized under pressure.
Moreover, in accordance with the preferred aspect of the invention,
the equipment is automatically controlled in a manner which insures
its reliable operation even in the absence of operating
personnel.
In accordance with one of the features of the present invention,
there is provided a unique application of a device known as a
vortex tube unit which is a relatively very compact T-shaped
structure comprising an inlet tube, a warm air outlet tube and a
cool air outlet tube, all joining an air rotating chamber which
separates faster moving molecules from the slower and cooler moving
molecules and directs the faster moving molecules to the warm air
outlet tube and the slower moving molecules to the cool air outlet
tube. By suitably controlling the ratio of the molecules collected
by the cool and warm air outlet tubes a suitable temperature
differential is obtained in the air leaving the warm and cool air
outlet tubes. For example, where 10 percent -30 percent of the air
passing into the vortex tube unit is collected by the warm outlet
tube, the temperature of the air therein can be from
220.degree.-310.degree.F hotter than the remaining 70 percent -90
percent of the air introduced into the unit which passes out of the
cool air outlet tube at a temperature below about 50.degree.F.
These temperature examples assume an input air temperature to the
vortex tube unit in the range of from 90.degree. to 119.degree.F.
The cool air flowing from the cool air outlet tube of the vortex
tube unit is fed to the input of a corona discharge ozone
generating unit, and the warm air flowing from the warm air outlet
tube of the vortex tube unit is fed to a gas drying unit not in use
for de-moisturizing the same. There is thus no need for bulky,
costly water jackets and air heaters heretofore used in most
commercial ozone generating systems.
In accordance with a specific aspect of the invention, timer
controlled valves are provided to direct the flow of the air to be
ozonized into one of the gas drying units and the warm air of the
warm air outlet tube of the vortex tube unit to another air drying
unit and to periodically switch the flow of these air streams
therebetween, so the presence of an operator is made
unnecessary.
The above and other advantages and features of the invention will
become apparent upon making reference to the specification to
follow, the drawings and the claims.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing the various paths of flow and the means
for drying, cooling and ozonizing the air in accordance with the
present invention;
FIG. 2 is a circuit diagram of the control circuit portion of the
air drying, cooling and ozonizing system of FIG. 1;
FIG. 3 is a view of a portable cart carrying all of the apparatus
shown in FIG. 1, except for the air compressor:
FIG. 4 is a horizontal sectional view through the housing shown in
the bottom portion of the cart shown in FIG. 3 in which housing the
ozone generating unit, high voltage transformer and associated
electrical apparatus is housed;
FIG. 5 is an end view of the housing shown in FIG. 4 with an end
panel removed; and
FIG. 6 illustrates the connection of the vortex tube unit to the
ozone generating unit shown in smaller scale in FIG. 5;
DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
In FIG. 1 is shown the air drying, cooling and ozonizing system of
the invention which includes a corona discharge ozone generating
unit 2 having three ozone generating tube assemblies 3, 3' and 3"
banded together in a common bundle and supported within a
cylindrical casing 5 made of a suitable molded insulating material
like poly vinyl chloride. (The design of the ozone generating unit
2 illustrated in the drawing is a joint invention of Romuald
Slipiec and the present co-inventor Ronald Schultz.) The ozone
generating tube assemblies 3, 3' and 3" respectively have pairs of
electrodes 4-6, 4'-6' and 4"-6" separated by insulating tubes (not
shown in FIG. 1) made of dielectric material like glass. The
corresponding electrodes of the various ozone generating tube
assemblies are connected to conductors 7a and 7b respectively
extending to the opposite ends of the secondary winding 8b of a
high voltage transformer 8. Because of the method of cooling of the
ozone generating unit 2, the secondary winding 8b of the
transformer 8 has a grounded center tap 8c which reduces voltages
with respect to ground to one half that which would be present in
the absence of such a ground, to reduce insulating requirements and
the hazards of the system in comparison to the conventional method
of cooling ozone generating units by grounded water cooled
jackets.
The primary winding 8a of the high voltage transformer 8 is shown
connected to an adjustable autotransformer 14 whose input is
connected to a suitable filter circuit 16 including an inductor 16a
and a capacitor 16b, and a control circuit 18 to be described in
detail and shown in FIG. 2 which controls the feeding of energizing
voltage to the autotransformer 14. The control circuit may control
110 to 220 volts AC appearing on input power lines 23-25. A
manually operable on-off switch 22 may be associated with one of
the lines 23 extending to a power plug 24 for controlling the
feeding of electric power to the entire system shown in FIG. 1.
One of the important aspects of novelty of the air drying, cooling
and ozonizing system shown in FIG. 1 is the unique application of
the vortex tube unit 26 which has not heretofore been considered
for use as an air cooling or heating means for any purpose
associated with ozone generating devices, let alone in the specific
manner shown in FIG. 1 and now to be described. The vortex tube
unit 26 has an inlet conduit 26a extending to the head portion 26b
where the inlet air is caused to flow in a circular path in a
manner wherein the higher speed air molecules are collected by a
warm air outlet conduit 26c and the slower moving molecules are
collected by a cool air outlet conduit 26d. The size of an aperture
at the end of the warm air outlet conduit 26c is controlled by
suitable adjustable means 26e. The adjustment of this aperture size
varies the ratio of the relatively high and low speed molecules
reaching the warm and cool air outlet conduits 26c and 26d, thereby
varying the relative temperatures of the air flowing in these
conduits.
In one successful operating ozone generating system, the following
exemplary conditions were present:
inlet air pressure to vortex tube unit 26 - 80 psi.
flow rate of inlet air -- 10 cfm
flow rate of air exiting from cool air conduit 26d - 8 cfm
temperature of air exiting from cool air outlet conduit 26d -
44.degree.F
Pressure of air exiting from cool air conduit 26c - 10 psi.
flow rate of air exiting from warm air outlet conduit 26c - 2
cfm.
The temperature of the air exiting from the cool air outlet conduit
26d of the vortex tube unit 26 which is connected to the conduit 9
extending to the inlet of the ozone generating unit 2 should be
kept within certain limits to assure both the effective operation
of the ozone generating unit 2 and prevent destruction of the
dielectric tubes to be described which separate the various pairs
of electrodes 4-6, 4'-6' and 4"-6". The dielectric tubes to be
described are made of a glass or other similarly frangible material
which can crack when subjected to stresses caused, for example, by
wide temperature differentials between the ends thereof. As
previously indicated, the main purpose of the cooling of the air
passing into the ozone generating unit 2 is to keep the temperature
conditions within the unit sufficiently low that the ozone will not
immediately dissociate upon being formed between the electrodes of
the unit. It is most desirable, therefore, that the temperature of
the incoming air fed to the ozone generating unit does not exceed
about 50.degree.F for most effective results. The temperature of
the air entering the ozone generating unit 2 has a lower limit from
the standpoint of avoiding extremes of temperatures within the unit
which might damage the dielectric tubes referred to. In the
equipment being described this lower limit is desirably of the
order of magnitude of about 25.degree.F.
The speed of the inlet air through the ozone generating unit is
also an important factor since the speed of movement also effects
the rate of cooling which the air involved achieves within the
ozone generating unit. In ozone generating units of the capacity
with which the present invention has its most important application
(i.e., ozone generating units capable of generating in the range of
from 2 to 500 grams of ozone per cubic feet of air), the air flow
rate is desirably in the range of from 1.3 to 1.5 cubic feet per
minute per square foot of electrode surface area.
Since the actual temperature conditions within the ozone generating
unit are not always predictable, to insure that the temperature
conditions within the unit do not reach damaging levels or levels
where the ozone will readily disassociate and therefore cause the
unit to operate inefficiently, there is most preferably provided
means for varying the average on time of the ozone generating unit
to limit the average amount of heat generated within the unit
caused by the ozone formation process as previously described. In
the most preferred form of the system illustrated, this is
accomplished by utilizing a temperature responsive means 37 placed
at the outlet end of the ozone generating unit 2 to sense the
temperature conditions of the ozonized air flowing from this unit.
When the temperature of this air reaches an undesirably high level
which would cause ozone dissociate or dielectric tube damaging
extremes of temperature within the unit, a control unit 39 is
rendered operable to disconnect the voltage to the high voltage
transformer 8 either on a continuous basis until the temperature
conditions referred to drop to a desired level or by varying the
relative repetitive on and off periods during which voltage is
applied to the transformer 8. In the latter case, the control unit
39 may be a conventional proportional controller which has a
temperature set point manual control knob 39a which sets a
particular control temperature. When the temperature of the air
exiting from the ozone generating unit 2 is at the control
temperature, a 50 percent duty cycle could be provided where
energizing voltages to the high voltage transformer are alternately
switched on and off over equal periods of time. When the
temperature of the outlet air exceeds the set limit of the
proportional controller by progressively increasing amounts, the
proportion of time in each control cycle the voltage applied to the
high voltage transformer becomes progressively less than 50
percent. On the other hand, when the temperature of the air exiting
the ozone generating unit 2 progressively decreases from the set
point temperature, the proportion of the on period of each control
cycle progressively increases from 50 percent. In one exemplary
proportional controller, the controller operated at a frequency of
5 cycles per minute, and provided a set point at 90.degree.F where
continuous off and continuous on conditions respectively for
temperatures 1/2.degree. above and below the set point
temperature.
The portion of the air flow and control system just described which
automatically limits the outlet temperature of the ozone generating
unit is a sole invention of the applicant Robert Tenney.
The warm air produced by the vortex tube unit 26 is uniquely used
in the air flow and control system shown in FIG. 1 to maintain the
air to be ozonized in a dry condition. Moist air in the ozone
generating unit undesirably greatly reduces the efficiency of the
ozone generating process and can create short circuit conditions
within the ozone generating unit. To this end, the warm air outlet
conduit 26c of the vortex tube unit 26 is connected to a conduit 38
leading to a pair of branch conduits 38a and 38b in which a pair of
one way pressure responsive valves 40a and 40b are located for
selectively opening or closing the associated branch lines. Each of
thes valves is open when the pressure on the side thereof nearest
the warm air outlet conduit 26c of the vortex tube unit 26 is
higher than the pressure on the opposite side thereof and is closed
when the pressure on the side thereof nearest the warm air outlet
conduit 26c of the vortex tube unit 26 is equal to or less than the
pressure on the opposite side thereof.
The branch conduits 38a and 38b respectively join a pair of
passageways extending between openings 37a and 37b in a pair of
dryer units 42a and 42b and a common conduit 44 extending or
connected to the inlet of the vortex tube unit 26. The latter
passageways are formed by conduit sections 39a-39a' and 39b-39b'
extending to the common conduit 44. One way pressure responsive
valves 41a and 41b are respectively located in the conduit section
39a' and 39b'. Branch conduits 38a and 38b intersect the juncture
of the conduit sections 39a-39a' and 39b-39b' respectively. Each of
the pressure responsive valves 41a and 41b is open when the
pressures on the side thereof nearest the associated dryer in
higher than the pressure on the opposite sides thereof and is
closed when the pressure on the sides of the valves 41a and 41b
nearest the associated dryer is equal to or less than the pressure
on the opposite side thereof. The conduit 44 is connected to the
inlet side of vortex tube unit 26 by a filter 46 which filters
non-gaeous substances from the air, a conduit 48, and a surge
suppressor 51 which eliminates or reduces sudden substantial
pressure changes occurring in the input thereto.
Associated with the conduit 48 adjacent the suppressor 51 and the
inlet of the vortex tube unit 26 are a pair of control elements
which respond to the pressure and the flow rate of the air flowing
in the conduit 48. Thus, a pressure responsive switch (not shown in
FIG. 1) is electrically connected by conductor means 64 to the
control circuit 18. The pressure responsive switch prevents the
control circuit 18 from connecting the power lines 23 and 25 to the
autotransformer 14 until the pressure within the conduit 48 reaches
a given desired value which will insure proper operation of the
vortex tube unit 26. Conductor means 66 extends between a flow rate
unit 67 attached to the conduit 48 and the control circuit 18. The
flow rate unit includes contacts, not shown in FIG. 1, which
operate when the flow rate reaches a given desired value. It is
also undesirable to permit the ozone generating unit to be operable
unless air is flowing therethrough at a desired minimum rate. Thus,
when both proper pressure and flow rate conditions exist, the
control circuit 18 is conditioned to interconnect the power lines
23 and 25 with the autotransformer 14, provided the timer and delay
means to be described forming part of the control circuit 18 have
been rendered operable.
The dryers 42a and 42b each provide for the flow in one direction
or the other therethrough of air to be dried and ozonized or warm
air for drying the interior thereof. The dryers 42a and 42b may be
conventional dryers which include dessicant materials which absorb
moisture and which become saturated and need to be dried in order
to be once again effective to perform a moisture absorbing
function. The openings 37a and 37b in the dryers 42a and 42b each
act in one mode of operation of the associated dryer as an exitway
for dried air and in another mode of operation thereof as an
entryway for warm de-moisturizing air from the warm outlet conduit
26c of the vortex tube unit 26. When the opening 37a or 37b of the
dryer 42a or 42b acts as an exitway for dried air, the pressure
thereof will effect closure of the valve 40a or 40b in the
associated conduit branch line 38a or 38b, and the opening of the
valve 41a or 41b in the branch conduit 39a' or 39b'. At any one
time, only the dryer 42a or 42b will receive air to be dried, and
thus at any given moment of operation of the system the opening 37a
or 37b of one of the dryer units 42a or 42b will be connected to
the inlet of the vortex tube unit 26 while the other of same will
be connected to the warm air outlet conduit 26c of the vortex tube
unit 26. Thus, while one of hte dryers is being used for drying air
being fed therethrough, the other dryer is automatically being
de-moisturized by warm air fed thereto from the vortex tube unit
26.
The source of air to be ozonized initially passes through a
compressor 50, which may be part of a permanent installation in a
given plant in which the ozonizing operation is to be performed.
The compressor delivers at the output thereof air at a suitable
pressure (for example, 90 lbs. per square inch) as measured by a
suitable pressure meter 52 associated therewith. The source of air
under pressure is then fed through a conduit 53 to a suitable
filter 54 which removes most of the non-gaseous material carried in
the air. The air leaving the filter 54 then flows to one of two
conduits 56a or 56b in which are located timer controlled solenoid
valves 58a or 58b. The conduits 56a-56b extend respectively to the
inputs of the dryer untis 42a and 42b at which pressure meters 57a
or 57b may be located. The warm de-moisturizing air passing through
the dryers 42a or 42b at any given moment leaves the associated
dryer through an exit conduit 43a or 43b in which is located a
timer controlled solenoid valve 45a or 45b. The conduits 43a and
43b join a common conduit 49 extending to a discharge point for
mosit air. An electrically operated timer 59 controlled by the
control circuit 18 operates the pairs of solenoid valves 45a-45b
and 58a-58b so that only one of the valve pairs 45a-58b or 45b-58a
are open at one time, so that air to be dried flows through one of
the dryers while the other dryer receives warm de-moisturizing air
from the warm air outlet conduit 26c of the vortex tube unit
26.
In accordance with a sole invention of co-inventor Robert Tenney,
upon closure of the main power switch 22 to initiate energization
of the system illustrated in FIG. 1, the control circuit 18, which
may include another timer to be described, initially energizes the
valve timer 59 to effect opening of one of the valve pairs 45b-58a
or 45a-58b, while keeping the connection between power lines 23-25
temporarily decoupled from the auto-transformer 14. This enables
dry air to flush through the ozone generating unit 2 to eliminate
moisture which may have previously gained access thereto before
voltage is applied thereto. After a given time delay, like five
minutes or so, the control circuit 18 then connects power lines 23
and 25 to the autotransformer 14 which energizes the high voltage
transformer 8 to start an ozone generating operation within the
ozone generating unit 2. The control circuit 18 preferably also
includes a timer which is adjusted by a control knob 18a which must
be rotated from its home position to enable the control circuit 18
to energize the various electrical devices connected thereto and
after a selected time period is returned to home position to
de-energize all of the devices. The timer portion of the control
circuit 18 is most advantageously so designed that the voltage on
the power lines 23-25 will be disconnected from the autotransformer
14 a given period (like five minutes or so) ahead of the time when
the valve timer 59 is de-energized to close off the solenoid
operated valves 45a-45b and 58a-58b, so the dry air flushes through
the ozone generating unit 2 after termination of the corona
discharge therein.
Refer now to FIG. 2 which shows an exemplary and preferred control
circuit 18. This control circuit includes a main timer 80 having an
electric motor 81 with one terminal connected to power line 25 and
the other terminal connected to cam operated contacts 90, in turn,
connected to power line 23. The movable part of the cam operated
contacts 90 is connected to a cam follower 86 which rides on the
periphery of a cam C1 having a narrow depression 82. When the cam
C1 is in its initial or home position, the cam follower 86 rides
within the depression 82 to open the contacts 90 de-energizing the
motor 81. The shaft of the cam C1 is turned by the aforementioned
manually operable control knob 18a which is rotated from its home
position in one direction to a degree depending upon the length the
ozone generator unit 2 is to be operated. (Cam C1 is rotatable
manually in only this direction to set the timer to the desired
timing period.) The shaft of the motor 81 is coupled to the shaft
of the cam C1 by suitable gearing so that cam C1 is rotated one
revolution for the maximum timing period of the timer. The motor 81
operates the cam C1 in the opposite direction to return the
depression 82 thereof to the point where the follower 86 falls
therein, resulting in opening of the contacts 90 and
de-energization of the timer motor 81. Any rotation of the cam C1
from its home position will cause the cam follower 86 to ride upon
the raised portion of the cam surface to close the contacts 90.
Cam C1 is ganged to a second cam C2 which has a 5 minute longer
depression 84. A cam follower 88 carrying the movable part of cam
operated cotnacts 92 rides on the periphery of the cam C2. When the
cam follower 88 rides in the depression 84, the cam operated
contacts 92 are open and when it rides on the raised portion of the
cam C2 the cam operated contacts 92 are closed. Since the
depression 84 of cam C2 is longer by 5 minutes than the very narrow
depression 82 of the cam C1, the contacts 92 will close 5 minutes
before the contacts 90 as these cams approach their home position
where the timer 80 becomes de-energized.
A power bus 94 extends the junture of electric motor 81 and the cam
operated contacts 90, on the one hand, and branch lines 96 and 98
respectively extending to one of the terminals of the valve timer
59 and the proportional controller 39 whose opposite terminals are
connected to the other power line 25. Thus, the valve timer 59 and
the proportional controller 39 are energized as long as the motor
81 is energized, that is until the cam C1 returns to its home
position where the depression 82 thereof receives the follower 86
which then opens the contacts 90 and de-energizes the timer motor
81.
Another branch circuit extends between the power bus 94 and power
line 25 and includes a series connection of the aforementioned
pressure responsive switch 64', whcih closes when a given pressure
level is reached in conduit 48 connected to the input of the vortex
tube unit 26, a flow rate responsive switch 67' which closes when
the air flow in the conduit 48 reaches a given flow rate, contacts
92 and timer delay relay 100.
The autotransformer 14 is located in a branch circuit 99 of the
control circuit 18 in parallel with the timer delay relay 100. This
branch circuit extends from the power line 25 through the
autotransformer winding 14a and filter inductor 16a, contacts 102
and 104 which are interlock switches on panels forming the housing
in which a high voltage transformer is located, contacts 39' which
are alternately opened and closed by the proportional controller 39
as previously described, and time delay relay contacts 100' of the
time delay relay 100. Thus, it can be seen, that the
autotransformer winding 14 and the high voltage transformer 8
coupled thereto as shown in FIG. 1 will receive energizing voltage
in accordance with the duty cycle determined by the proportional
controller 39 beginning 5 minutes after initiation of energization
of the main timer 80. The energization of the autotransformer 14
terminates 5 minutes before the timer returns to its home
position.
FIGS. 3-6 illustrate the most advantageous form for the ozone
generating system of the present invention which is compact,
portable and inexpensive in comparison to prior ozone generating
systems of similar capacity. As best shown in FIG. 3, all the
components shown in FIG. 1, except the compressor 50, are carried
on a portable cart 110 on which is supported a metal housing 112
containing, among other things, the ozone generating unit 2, the
vortex tube unit 26, the high voltage transformer 8, filter 16 and
the autotransformer 14. The cart 110 has an upper shelf 110b from
which upwardly extends along the center portion thereof a mounting
panel 100c on which may be mounted other portions of the air flow
and control system as shown in FIG. 1, such as the dryer units
42a-42b, timer operated valves 45a-45b and 58a-58 b, main timer 80
and the other valves 40a-41a and 40b-41b and associated conduits,
filter 46 and suppressor 51.
An exemplary positioning of the various elements within the housing
112 are shown in FIGS. 4-6. FIG. 4 illustrates the interlock
switches 102 and 104 are normally closed when the end panels 112a
and 112a' of the housing 112 are closed and which open when the
associated panels are removed from the housing 112 by loosening of
screws 114 and 114'.
It should be apparent that the preferred ozone generating system
including the various control features therefore previously
described result in an exceedingly reliable, compact and economical
automatically controlled ozone generating system which can be
mounted on a portable cart where desired, so that the equipment can
be readily moved to a desired location in a plant.
It should be understood that numerous modifications may be made in
the most preferred form of the invention described without
deviating from the broader aspects of the present invention.
* * * * *