U.S. patent number 3,899,684 [Application Number 05/475,760] was granted by the patent office on 1975-08-12 for control system for corona discharge ozone generating unit.
This patent grant is currently assigned to Ozone Incorporated. Invention is credited to Robert I. Tenney.
United States Patent |
3,899,684 |
Tenney |
August 12, 1975 |
Control system for corona discharge ozone generating unit
Abstract
A control system for an ozone generating system includes a
temperature responsive portion which is responsive to the
temperature of the ozonized gas by interrupting the coupling of
high voltage to the electrodes of an ozone generating unit when the
temperature of the ozonized gas reaches a level below the
temperature at which said ozonized gas rapidly dissociates, the
circulation of the gas to be ozonized through said unit continuing
during the interruption of high voltage, and a timer sequencing
portion for automatically initiating circulation of air through the
ozone generating unit a given predetermined period prior to the
coupling of high voltage to the electrodes of the ozone generating
unit and for automatically terminating the coupling of high voltage
to said electrodes of the ozone generating unit a given period
prior to termination of air circulation when ozonization is to be
terminated.
Inventors: |
Tenney; Robert I. (Deerfield,
IL) |
Assignee: |
Ozone Incorporated (Deerfield,
IL)
|
Family
ID: |
23889012 |
Appl.
No.: |
05/475,760 |
Filed: |
June 3, 1974 |
Current U.S.
Class: |
422/186.11; 62/5;
422/186.15; 96/130; 96/112 |
Current CPC
Class: |
C01B
13/11 (20130101); C01B 2201/66 (20130101); C01B
2201/90 (20130101) |
Current International
Class: |
C01B
13/11 (20060101); C01b 013/12 (); F25b
009/02 () |
Field of
Search: |
;250/532-541 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
369,461 |
|
Mar 1932 |
|
GB |
|
808,635 |
|
Feb 1937 |
|
FR |
|
Primary Examiner: Mack; John H.
Assistant Examiner: Weisstuch; Aaron
Attorney, Agent or Firm: Wallenstein, Spangenberg, Hattis
& Strampel
Claims
I claim:
1. In an ozone generating system including a corona discharge ozone
generating unit for ozonizing an oxygen containing gas, the
ozonized gas rapidly dissociating at temperatures above a given
value, the ozone generating unit including at least one pair of
electrodes to be connected to the terminals of a high voltage
source and a heat damageable dielectric tube between said
electrodes, a source of ozone producing high voltage to be operably
connected to said electrodes and means for circulating the oxygen
containing gas to be ozonized through said corona discharge
generating unit, the improvement in means for controlling the
operation of the ozone generating system, said means comprising
temperature responsive means responsive to the temperature of the
ozonized gas, and control means responsive to said temperature
responsive means for interrupting the coupling of said ozone
producing high voltage to said electrodes of the ozone generating
unit when the temperature of the ozonized gas reaches a level below
the temperature at which said ozonized gas rapidly dissociates, the
circulation of the gas to be ozonized through said unit continuing
during said interruption of the high voltage.
2. The ozone generating system of claim 1 wherein said control
means interrupts the coupling of said ozone producing high voltage
to said electrodes of said ozone generating unit when the
temperature of the ozonized gas reaches a level of at least about
90.degree.F.
3. The ozone generating system of claim 1 wherein said control
means includes a proportional controller with means for setting a
temperature at which the controller alternately establishes and
interrupts the presence of said ozone producing high voltage across
said electrodes.
4. The ozone generating system of claim 1 wherein there is provided
means for cooling the gas to be ozonized to aid in preventing the
build-up of dielectric shield damaging temperatures in the ozone
generating unit and the temperature at which the ozonized gas
rapidly dissociates.
5. The ozone generating system of claim 1 wherein there is provided
gas flow rate responsive means and means for preventing the
coupling of high voltage to said electrodes of the ozone generating
unit until the flow rate reaches a given value.
6. The ozone generating system of claim 5 wherein there is provided
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, said
cool gas outlet being connected to the inlet of the ozone
generating unit, said vortex tube unit requiring gas of at least a
given pressure to be operable and there is provided pressure
responsive means responsive to the pressure of the gas to be
ozonized being fed to the inlet of said vortex tube unit and means
for preventing the coupling of high voltage to said electrodes of
the ozone generating unit until the pressure reaches said given
pressure.
7. An ozone generating system including a corona discharge ozone
generating unit for ozonizing an oxygen containing gas, the
ozonized gas rapidly dissociating at temperatures above a given
value, the ozone generating unit including at least one pair of
electrodes to be connected to the terminals of a high voltage
source and a heat damageable dielectric tube between said
electrodes, a source of ozone producing high voltage to be operably
connected to said electrodes and means for circulating the oxygen
containing gas to be ozonized through said corona discharge
generating unit, drying means for drying the gas to be ozonized,
and control means for first automatically initiating operation of
said circulating and drying means a given predetermined period
prior to the coupling of said ozone producing high voltage to said
electrodes of the ozone generating unit and then to couple said
ozone producing high voltage to said electrodes of the ozone
generating unit in order to substantially insure the drying out of
the ozone generating unit before the high voltage is fed
thereto.
8. The ozone generating system of claim 7 wherein there is provided
timer controlled means for terminating the coupling of said high
voltage to said electrodes of the ozone generating unit a given
period prior to termination of the operation of said circulating
means to prevent overheating of the ozone generating unit and
retention of ozone in the unit.
9. An ozone generating system including a corona discharge ozone
generating unit for ozonizing an oxygen containing gas, the
ozonized gas rapidly dissociating at temperatures above a given
value, the ozone generating unit including at least one pair of
electrodes to be connected to the terminals of a high voltage
source and a heat damageable dielectric tube between said
electrodes, a source of ozone producing high voltage to be operably
connected to said electrodes and means for circulating the oxygen
containing gas to be ozonized through said corona discharge
generating unit, and timer controlled means for terminating the
coupling of said high voltage to said electrodes of the ozone
generating unit a given period prior to termination of the
operation of said circulating means to prevent overheating of the
ozone generating unit and retention of ozone in the unit.
10. The ozone generating system of claim 9 wherein there is
provided timer controlled means for automatically initiating the
coupling of said high voltage to said electrodes of the ozone
generating unit a given period after initiation of operation of
said circulating means.
11. In an ozone generating system including a corona discharge
ozone generating unit for ozonizing an oxygen containing gas, the
ozonized gas rapidly dissociating at temperatures above a given
value, the ozone generating unit including at least one pair of
electrodes to be connected to the terminals of a high voltage
source and a heat damageable dielectric tube between said
electrodes, a source of ozone producing high voltage to be operably
connected to said electrodes and means for circulating the oxygen
containing gas to be ozonized through said corona discharge
generating unit, the improvement coupling 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, said cool gas outlet being connected to
the inlet of the ozone generating unit, said vortex tube unit
requiring gas of at least a given pressure to be operable, and
there is provided pressure responsive means responsive to the
pressure of the gas to be ozonized being fed to the inlet of said
vortex tube unit, and means for preventing the coupling of said
ozone producing high voltage to said electrodes of the ozone
generating unit until the pressure reaches said given pressure.
Description
BACKGROUND OF THE INVENTION
This invention relates to ozone generating equipment wherein 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 AC voltage. 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 at 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 generating unit remote from the cooling
jackets.
Prior ozone generating systems require the presence of an operator
to start the same into operation, switch over from a saturated air
drying unit to one which has been dried out and therefore is ready
to receive air to be ozonized, and to check the temperatures of the
air in the system to avoid the destruction of the equipment by
excessive temperatures which may be developed in the ozone
generating unit.
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
In accordance with one of the features of the invention,
overheating of both the ozone generating unit and the ozonized air
is prevented by providing means responsive to the temperature of
the ozonized gas, and control means responsive to the temperature
responsive means for at least temporarily terminating the operation
of the ozone generating unit when the temperature of the ozonized
gas reaches a level (like about 90.degree.F) below the temperature
at which the gas rapidly dissociates, which is generally a
temperature of about 150.degree.F. This termination of operation of
the ozone generating unit is most advantageously achieved by
interrupting the coupling of high voltage to the electrodes of the
ozone generating unit so the circulation of the gas to be ozonized
continues during the temporary interruption of the high voltage.
This has the advantage of purging the equipment of any ozone which
could be destructive to various surfaces in the ozone generating
unit if circulation of the air to be ozonized were to be terminated
before the system is flushed, and also preventing overheating of
the dielectric tubes of the ozone generating unit where the flow of
air to be ozonized through the ozone generating unit is used to
cool the surfaces thereof which are heated by the corona discharge
and the release of heat during the ozonization process.
The means for terminating the coupling of high voltage to the
electrodes of the ozone generating unit is most advantageously
achieved with a proportional controller which may be of
conventional design with means for setting a temperature at which
the controller alternately establishes and interrupts the presence
of high voltage across the electrodes at a duty cycle to maintain a
given temperature within the control range thereof. This duty cycle
is preferably about 75 percent.
In accordance with another feature of the invention, an automatic
control circuit is provided for the ozone generating system which,
when the equipment is initially turned on, permits the air
circulating means to circulate air through the ozone generating
unit a given predetermined period before high voltage is
automatically connected to the ozone generating unit. This insures
the drying out of the system before application of voltage, which,
if applied when there is moisture still accumulated in the system,
could result in arcing and damage to the dielectric shields of the
ozone generating unit. In accordance with a related feature of the
invention, the automatic control circuit also insures when the
equipment is to be turned off that the high voltage is first
disconnected from the electrodes of the ozone generating unit
before air circulation is terminated, so that ozone is purged from
the system and portions of the ozone generating unit which have
been heated up can be cooled by the passage of air through the
ozone generating unit.
In accordance with another aspect of the invention, the air
circulated through the ozone generating unit is pre-cooled by a
vortex tube unit which separates relatively fast and slow moving
molecules and directs the relatively high speed moving molecules to
a warm air outlet and directs the relatively slow moving molecules
to a cool air outlet, thereby providing air flows of two widely
different temperatures. The cooler air is circulated through the
ozone generating unit. The proper operation of a vortex tube unit
requires that the pressure of the gas at the inlet side thereof be
at least a given pressure to enable the unit properly to separate
out the molecules in the proper proportion to achieve an air
temperature at the cool air outlet thereof to effect the desired
amount of cooling within the ozone generating unit. Additionally,
while the vortex tube unit may receive gas at a proper minimum
pressure, blockage of air flow through the ozone generating unit
would interrupt proper cooling of the ozone generating unit even
though the pressure at the inlet to the vortex tube unit has
reached or exceeded a desired limit. In accordance with this
feature of the invention, there is provided a control circuit which
automatically disconnects the feeding of high voltage to the
electrodes of the ozone generating unit when the pressure of the
air at the inlet to the vortex tube unit drops below a given level
and also when the air flow rate drops below a given level.
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 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
FIG. 1 shows an ozone generating unit 2 having three dielectric
tube and electrode 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 drawings
is a joint invention of Romuald Slipiec and the present co-inventor
Ronald Schultz.) The dielectric tube and electrode assemblies 3, 3'
and 3" respectively have pairs of electrodes 4-6, 4'-6' and 4"-6"
separated by insulating tubes (not shown) made of a 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 or 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 which is a joint invention of
myself and Ronald Schultz 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 along 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 24 - 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 -
45.degree.F
pressure of air exiting from warm 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 preventing destruction of the
dielectric tubes which separate the various pairs of electrodes
4-6, 4'-6' and 4"-6". The dielectric tubes 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 disassociate 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 the
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 100 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, in accordance with one of the
features of the present invention there is 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 approaches an undesirably high level which
would cause ozone disassociation 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 or control temperature range. When
the temperature of the air exiting from the ozone generating unit 2
is within this range, a given duty cycle is provided where
energizing voltage to the high voltage transformer is alternately
switched on and off over given relative proportions of time
depending upon the given conditions. When the temperature of the
outlet air exceeds the upper limit of this range, the controller
continuously interrupts the coupling of high voltage to the
electrodes, and below this temperature the controller couples the
high voltage to the electrodes during progressively increasing
percentages of each cycle until the lower limit of the control
range is reached where the voltage is continuously coupled to the
electrodes. In one exemplary proportional controller, it operated
at a frequency of 5 cycles per minute, was adjusted to provide a
control range of 1.degree.F and a full off temperature of
90.degree.F. Below this temperature, the duty cycle progressively
increased to 100 percent at 80.degree.F. A duty cycle of about 75
percent on time each cycle is preferred. This duty cycle is
achieved by varying the magnitude of the high voltage and/or the
flow rate.
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
these 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
pressure on the side thereof nearest the associated dryer is 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-gaseous 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.
In accordance with another feature of the invention, associated
with the conduit 48 adjacent to 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 the 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 an output 50a 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 units 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
moist 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 5
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 5 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 contacts 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 between the juncture 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', which 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 autotansformer 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 having rollers 111. The cart is shown as
having a lower shelf 110a 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 110c 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-58b, 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 which are normally closed when the end panels
112a and 112a' of the housing 112 are closed and which open when
the associated panels 112a and 112a' 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.
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