Note: Descriptions are shown in the official language in which they were submitted.
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DUST PRECIPITATION FROM AIR BY NEGATIVE IONIZATION
BACKGROUND OF THE INVENTION
This invention relates to a system for dust precipitation from air using
negative ionization of the air.
The concept and prospective commercialization of negative ionization
techniques has been around for decades with very little progress due to the lack of
credibility arising frolh inappropriate, largely unsuccessful applications and clouded by
exaggerated unsubstantiated claims.
At the same time the effectiveness of the technique suffered because the
equipment to generate and distribute the required volumes of negative ions was initially
bulky, expensive, requiring constant maintenance and was generally unreliable. These
circumstances meant that the effectiveness of applications deteriorated rapidly and
became totally suspect in operation.
The increasing employment of the technology is being brought about by
some basic trends:
- the development of equipment utilizing electronics and new
materials which provide a safe, reliable, inexpensive, and non polluting source of
negative ions and their distribution.
- an increasing need to improve the air quality in enclosed
environments which have been designed to minimize energy costs for heating,
ventilating and air conditioning installations.
- higher standards of safety and health in the workplace in regard
to the control of micronic and submicronic pollutants identified as a health hazard.
- zero defect objectives in manufacturing operations requiring more
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effective means to control the migration of fine dust and pollutants.
- hard evidence of the etfectiveness of industrial applications and
increasing supportive scientific evidence as regards proper electro climate conditions
for human comfort and working efficiency.
Off-shore countries, particularly Israel have maintained a fairly high
level of research and development effort into purslling the effectiveness of negative
ionization techniques in a wide range of applications with considerable success.Progress in North America in thiS respect, industrially at least, has been
limited to the elimination of static electricity, but with strong indications of a recent
revival of air treatment by modular, fan assisted negative ion dispersal units.
Conventional systems to obtain super clean air with filtration efficiencies
in the micronic and sub-micronic ranges are capital intensive and expensive to run in
terms of energy consumption and maintenance costs.
At the same time the systems while fully eftective on the air circulated
can have little influence to prevent small particulants and pollutants originating in the
working plennum producing problems, apart from the inherent dilution refreshening
process allowed by the cycle of air changes supplied to the area- An investigation into
further prior act suggests that while the use of negative ionization techniques to
improve air quality and contain dust pollution in a general way is gaining ground, there
is little doubt that the level of technology available is relatively crude.
Ions are created in nature by sunlight, cosmic and terrestrial radiation
and the friction of moving air and water that causes electrons to leave hydrogen,
nitrogen and other molecules and to attach themselves to oxygen molecules.
Molecules with extra electrons from negative ions and have a positive
effect on the environment. They neutralize odours and contribute to the clear air and
the fresh smell we ~;nd in non-industrial, sparsely populated areas and at the seaside or
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healthy holiday resorts.
In the Prairie regions of Canada, the phenomenon best manifests itself
by the invigoration experienced at`ter a summer storm with lightning, which relieves the
heavy depressing conditions which gradually build up periodically in such areas during
the summer.
Positive ions are produced by car and factory exhausts, cigarette smoke,
dust, soot, fumes from new processes and other domestic and industrial pollutants.
In the wide open spares these pollutants are attracted to the negative
ground and are harmlessly discharged. But in the enclosed environments of modernsociety - metals, cars, buildings lined and furbished with synthetic materials, etc., these
pollutions cannot be discharged to earth.
At the same time the enveloping car bodies and building structures that
keep the positive ions in, also keep the beneficial negative ions out because their
electrical charges are absorbed by steel and concrete, bricks and siding material.
A controlled output of negative ions can be produced by electronic
means/corona discharge and this source is an approved alternative for the Poionium
Ionizers withdrawn from the market by 3M in February 1988. The source generationof ozone is so low as to be almost immeasurable and well below the FDA maximum of
0.05 ppm.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide an improved method
for cleaning air within a building using the negative ionization principles in a unique
manner to obtain air which is cleaned to a high degree with low capital and
maintenance costs.
According to a first aspect of the invention, therefore, there is provided
a method of precipitating particles t`rom air within a building comprising defining a
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zone within the building at least partly partitioned from a remaining part of the
building, separating the zone from the building by a screen which is perforated to allow
transmission therethrough of air and light, and mounting within the zone a plurality of
emitters of negatively charged air ions.
According to a second aspect of the invention, therefore, there is
provided an emitter of negatively charged air ins for use in precipitating particles from
air within a building comprising an elongate member defming a channel therealong and
having a closed front surface, a conductor mounted in the channel member, means
defining a plurality of openings in front surtace through which portions of the
conductor project, and connector means on the channel member for connecting a high
voltage to the conductor such that the exposed portions of the conductor generate ions
in air exposed to the conductor forwardly of the front face.
The provision of the elongate multiple emitter enables a high very degree
of flexibility to be used in the location and mounting of the emitters for the negative
ionization treatment so that the units can be installed very quickly and at low capital
cost.
The use of the screen to separate the zone to be cleaned from the
remainder of the building enables a system to be used known as a "clean-zone" or as an
alternative a "reverse clean-zone" in which the major dust emitting process is mounted
within the zone and the negative ionization treatment used to extract the dust from the
air prior to its release to the remainder of the building.
The screen is preferably formed of a material which is permeable to air
and light so that the zone can be mounted within the building without regard to the
location of the ventilation units and provision of lighting. In many cases, therefore, the
zone can be developed at an area leaving the ventilation systems and lighting systems
outside of the zone so that there is no interference whatever with the existing utilities
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within the building. The light and air movement necessary for ventilation can then take
place through the screen with the screen and the negative ionization system cooperating
to extract the dust and to prevent its penetration through the screen.
The system as installed, constantly and efficiently will precipitate about
99% of the fine dust particles and pollutants in a work area defined and isolated by
specially constructed barrier screens.
With the correctly calculated and distributed negative ion density within
the zone, all further migration of the precipitation micronic and submicronic particles
will be effectively and continuously prevented, as a result of the electro-climate created
and maintained in the "Clean Zone" area.
The emitters are preferably separated from any air flow generating
systems such as fans or air duct outlets so that the ions are freely emitted into the area
to be cleaned without passage of the ions or any air stream carrying the ions through a
filter. Thus the particles are separated from the air by a precipitation technique which
causes the particles to fall to the floor tor collection by conventional house cleaning
techniques.
The enclosure which acts as a cage to isolate and define the area/volume
required for the application, is considered to be a basic and essential feature of the
"clean zone" concept. The design, construction and materials employed, all contribute
to ensuring the effectiveness of the system.
Installation of the "Clean Zone" enclosure is simple and flexible and
easily fitted retro-actively with the minimum difficulty to accommodate existingequipment.
The light open nature of the enclosure gives little sense of restriction to
employees inside the zone and it is generally unnecessary to upgrade lighting levels in
the area after the installation of the zone.
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The effectiveness of the system is readily measurable and can be
demonstrated by the simple action of energizing and de-energizing the AC power input.
The results in regard to the control of fme dust, and reduction of
inclusions are fully substantiated in practical cost effective terms by satisfied industrial
end users in regard to:
- reduced level of rejections due to inclusions;
- increased productivity
- improved working environment inside and outside the zone.
According to a third aspect of the invention, there is provided a method
of cleaning particles from air within an area of a building comprising mounting emitters
of negatively charged ions in the area of the building separate from any air flow
arrangements for causing air flow within the area, causing the ions to engage particles
in the area and to precipitate the particles downwardly onto a floor of the area and
collecting the particles from the floor.
Preferably the method includes a canopy which assists in directing the
particles away from a source of the particles e.g. a dust producing machine towards
sides of the machine for precipitation on the floor.
With the foregoing in view, and other advantages as will become
apparent to those skilled in the act to which this invention relates as this specification
proceeds, the invention is herein described by reference to the accompanying drawings
forming a part hereof, which includes a description of the best mode known to the
applicant and of the preferred typical embodhnent of the principles of the present
invention, in which:
DESCRIPTION OF THE DRAWINGS
Figure I is an isometric view showing a screen system defining a zone
for separation from the remainder of building and including ionization generating
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elements mounted within the zone.
Figure 2 is a top plan view of the zone of Figure I showing the location
of the ion emitters.
Figure 3 is a cross-sectional view showing a modified arrangement of
screen assembly defining a zone within a building.
Figure 4 is a cross-sectional view through an emitter element of a type
shown schematically in Figures 1 and 2.
Figure S is an isometric view of the emitter element of Figure 4.
Figure 6 is a cross-sectional view through a second emitter element of
the type illustrated schematically in Figure 1.
Figure 7 is an isometric view of the emitter of Figure 6.
Figure 8 is a cross sectional view showing a modified arrangement of the
screen assembly of Figure 3.
Figure 9 is a cross sectional view showing one end of a conduit, the
adjacent end of an emitter and the connector element therebetween.
Figure 10 is a cross sectional view along the lines 10-10 of Figure 9.
Figure 11 is an top plan view of one portion of the emitter of Figure 9.
Figure 12 is an isometric view on an enlarged scale of one portion of a
modified emitter for use in place of the emitter of Figure 9.
Figure 13 is a transverse cross sectional view through a further
embodiment of emitter taken along the lines 13-13 of Figure 14.
Figure 14 is a cross sectional view along the lines 14-14 of Figure 13.
Figure 15 is a schematic illustration of an emitter system including the
conduits and emitters of the type shown in Figures 9 or 12.
:~ Figure 16 is an isometric view of a further emitter construction.
Figure 17 is an isometric view of a portion the emitter construction of
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Figure 16 showing two alternative emitter elements.
Figure 18 is an isometric view showing schematically a rotating emitter
system.
In the drawings like characters of reference indicate corresponding parts
in the different figures.
DETAILED DESCRIPTION
In Figures 1 and 2 is illustrated a zone defined by a surrounding wall
structure generally indicated at 10 within which is mollnted a machine 11 which is
illustrated schematically and is wholly enveloped by the surrounding wall structure
defining the zone.
The wall structure comprises two side walls 12 and 13 together with end
walls 14 and 15 each of which includes an opening 16 and a slidable closing door 17.
Across the top of the walls is provided a ceiling 19. The height of the walls is arranged
to be approximately e~ual to the minimum working height of the order of eight feet and
up to a maximum of the order of ten teet so that the ceiling 19 is generally positioned
beneath the roof or ceiling structure of the building and is separate from the lighting,
duct work and other utilities which are often provided in stmctural buildings of an
industrial type.
This critical area or zone is enclosed using a slotted metal structure as
the main supportive framework, housing panels covered with perforated screen material
of a type which is permeable to air and light but is resistant to the passage of dust or
other fine particles. One example of material which can be used is known as TAK
Barrier Screening. The TAK Barrier Screening is a fine gauge fabric, treated with a
special tacky resin. This Barrier screening is electronically compatible with negative
ion presence and works harmoniously to create a dust free enclosure, trapping large
particles, yet allowing the zone to breathe without any increase in air speeds across the
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fabric.
The enclosure which acts as a cage to isolate and define the area/volume
required for the application is considered to be a basic and essential feature of the
"clean zone" concept. The design, construction and materials employed, all contribute
to ensuring the effectiveness of the system.
Installation is simple and flexible and easily, fitted retroactively with the
minimum difficulty to accommodate existing equipment.
The light open nature of the enclosure gives little sense of restriction to
employees inside the zone and it is generally unnecessary to upgrade lighting levels in
the area after the installation of the screens.
Strategically located emitters at ceiling level within the enclosure
produces a bombardment of negative ions to precipitate particles inside the zone. At
the same time a high density is created within the confines of the enclosure which will
not allow particles to penetrate the screens, in either direction.
All openings into the zone required for access are protected by a curtain
of ions which comprises a peripheral distribution of emitters to form an high density
concentration of directed negative ions to precipitate any dust which might otherwise
migrate into the area. Altogether a total screened, "cage" effect is produced with a
fully isolated Clean Zone separate and distinct from the general working area of the
facility.
On completion of a Clean Zone, and activation of the ion generation
system, an ultra Clean Zone will be established for process within 24 hours- This
protection will be available as long as the system is hl operation with the necessary
negative ions densities being maintained automatically at the proper levels.
The slotted steel frame work is hldicated at 20 and is of a conventional
nature available for receiving watt panels and for bug screens. A solid panel is
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indicated at 21 and the screen material is hldicated at 22.
The ceiling is formed in the same structure employing wholly the screen
material 22. The enclosure can thus be tormed relatively simply by the assembly of the
frame work following which the panels are simply flipped into place to define the
completed zone. In Figures 1 and 2 there is provided a plurality of emitters of negative
ions including two separate types of emitters indicated at 25 and 26 respectively. The
details of the emitters 25 are shown in Figures 6 and 7 and the details of the emitters 26
are shown in Figures 4 and 5.
Turning therefore to the emitters 25 shown in Figures 6 and 7, this
emitter comprises an elongate channel member 30 formed in two halves 31 and 32
which are snap fit together along a joining line 33 to form an enclosed elongate tubular
member. End caps 34 are provided of a type shown in Figure 4 which comprise a
press fit into the end of the tubular member thus t`orming a complete enclosure. The
emitter 26 as shown in Figures 4 and 5 comprises the same basic housing structure.
The length of the housing can be selected according tO requirements as shown in
Figures 4 and 5 the emitter is of a relatively short length whereas in Figure 6 and 7 the
emitter: 25 can be significantly longer-
Each of the housings includes a connector 36 of a type including a body37 which has an outer screw thread 38 and an end cap 39. The body can thus be
attached through an operating in the housing simply by clamping into place by one or
more nuts 40 and 41. In the arrangement shown in Figure 6 there are two nuts
provided each on a respective side of a wall. of the housing so as to spare the end cap
39 away from the wall. In the arrangement shown in Figure 4, the end cap is clamped
against the end face of the housing by the nut 40 on the opposed side of the wall of the
housing. The housing includes a central bore which carries a conductor 42 and a
volume of the sleeve which projects outwardly beyond the inner end of the body to
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connect to a conductor 43 provided within the housing. The tubular connector 42 is
thus of a type which can receive simply a single pole connector by which high voltage
from a generator 45 (Figure 2) can be connected to the emitter with a pluMlity of
emitters arranged in series by connection of a wire from each to the next.
The conductor 43 is formed of a yarn of a conductive fibre material for
example carbon fibres which are cut into staple fibres and then spun and twisted to
form a multi fold yarn- The housing is formed of very suitable insulating plastics
material so that the conductor yarn call simply be threaded into the housing and can rest
against the housing without forming a short circuit.
In Figures 4 and 5, a front face of the emitter which is defined by the
upper face of the upper pact 3 l has a plurality of openings 48 substantially equidistantly
spared along the front face in a single line across the centre of the front face. The yarn
is then threaded simply in a stitch pattern so that portions of the yarn are exposed on
the outer side of the t`ront tace and portions of the yarn are maintained on the inner side
of the front face that is within the housing as indicated at 49 and 50 respectively-
This form of emitter is substantially multi-directional so that when a high
voltage of the order of 6000 volts is applied to the conductor 43 the exposed portions
49 of the yarn generate a corona effect causing the creation of ions in the area of the
corona effect with those ions tending to escape trom the exposed portion of the yarn 49
in all directions away from the front surface- The ions thus tend to spread away from
the emitter in all directions and to attach to particles within the air. As the particles are
heavier than air the particles tend toward the ground surtace and in view of thegenerally positive charge on the ground surface, the negatively charged particles are
attracted to the ground surface and fall to the ground surface for collection on the
ground surface both in view of gravity and in view of the electrostatic attraction-
As shown in Figure 2, the emitters 26 are arranged in array around the
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centre of the zone. In the example shown there are four rows of the emitters arranged
substantially equadistantly spared across the width of the zone. In this way the full area
of the interior of the zone is bombarded with the ions which are spread equally
throughout the central area of the zone. As shown in Figure I the emitters 26 are
mounted at the ceiling area on suitable supports (not shown). This places the height of
the emitters generally at the height of the ceiling which would be in the order of eight
to ten feet from the ground which has been found to be particularly effective since the
ions are thus prevented from dissipation to other areas of the building before they can
carry out their function of attachment to particles and transporting those particles to the
around surface.
The emitter 25 shown in Figures 6 and 7 is modified relative to the
emitter 26 in that the conductor 43 is contined into short portions which project
outwardly from the front face of the channel member 31. Thus the front face 31
includes for each portion a pair of holes SS and 56 which are closely positionedtogether with only a narrow separating portion 57. The conductor is then threaded
through the holes 55 and 56 and passes through a collar member 58 surrounding the
holes and supporting the outerly projecting portion of the conductor 43 as indicated at
59. The collar member 58 can be bonded to the t`ront surface of the channel member
or can comprise a separately manufactured product which insects from an underside of
the upper surface of the channel member through a single hole in the wall 31 andprovides by itself the proper support for the projecting portion 59.
The projecting portion 59 is cont`ined to a short length of the front face
of the channel member is caused to turn back upon itself at a sharp angle. This tends
to cause individual ones of the staple fibres 60 to project outwardly from the yarn at the
point where it is turned sharply thus t`orming a plurality of spikes which project
outwardly from the sharply hlrned portion of the cond-lctor 43. These spikes have been
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found to generate ions in a highly directional manner in that the ions are preferentially
generated at the apex of the fibre spike and thus tend to be emitted in a direction
generally at right angles to the front face.
The emitter 25 is therefore much more directional than the emitters 26.
In view of this property, the emitters 25 are thus arranged to generate a curtain of ions
lying in a plane longitudinal of the emitter 25 and at right angles to the front face.
Turning therefore to Figure I the emitters 25 are mounted around the
opening 16 along the sides of the opening and along the top of the opening with the
emitters facing inwardly to generate a curtain across the plane of the opening of a high
concentration of ions. This curtain acts to "attack" any dust particles attempting to pass
through the opening so that those particles are acted upon quick~y and tend quickly to
fall to the around at the area of the opening. As a back up for the emitters 25 at the
opening, one or more rows of further emitters 25 can be positioned inwardly of the
opening. Thus in Figure 2 there are two further rows of emitters one positioned just
inside the opening and the next behind the ~ïrst thus forming three curtains of ions
acting specifically on the dust tending to move through the opening carried by persons
or equipment passing through that opening or by air movement through the opening.
The curtain of ions thus act at the openings in the zone and in addition
the general level of ions within the zone acts in cooperation with the permeable tacky
screen to cause dust and other particles to be collected at the screen rather than to pass
through the screen. It has been noted that the ions have a tendency to act upon the dust
just outside of the screen so that large quantities of particles fall to be collected on
ground or other horizontal surfaces just outside the screen thus preventing the dust from
passing through the screen.
As shown in Figure 3 there is provided a modified arrangement
including a floor surface 70, a machine 71, a screen 72, an upper ceiling 73 of the
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building and utilities including duct work 74 and lighting 75.
In this case the screen is modified in that it comprises simply a canopy
supported from the ceiling or roof on support wires 76. The canopy includes a ceiling
77 formed in panels similar to the ceiling 19 together with four side wall portions 78
which hang down from the side edges of the ceiling. The details of the construction are
not shown but are similar to that shown in Figure 1. This of course leaves the side
walls of the zone open for passage of persons or equipment but generates enough of a
sepaMtion of the zone from the building to enable the cleaning of dust from around the
machine 71. Figure 3 also illustrates the arrangement in which the zone is sepaMted
from the ventilation systems including the duct work 74 and from the lighting systems
which are maintained without modification in the building. The light into the zone is
thus provided by the conventional lighting of the building. The ventilation or air
movement within the zone is provided by the conventional building ventilation systems
including the duct work 74 and a nozzle 80 which projects air to move downwardlythrough the screen and into the zone.
In the arrangement of Figure 3, the dust is prevented from passing into
the interior of the zone through the open side walls by the generation of a curtain of
ions similar to that at the opening 16. Thus the emitters 25 are positioned so as to
generate a curtain projecting downwardly at the open side walls and this can be backed
up by one or more further rows of emitters 25 positioned inwardly of the side walls.
Also similar to the construction shown in Figures I and 2, interior emitters can be of
the type illustrated at 26 to generate a more even spread of ions throughout the zone.
In Figures I and 2 the machine 11 illustrated schematically comprises a
machine for carrying out an industrial- process of a type which requires very clean air
for example a paint spraying machine or pact molding machine so that this machine is
maintained within a clean zone in which the dust in the remainder of the building is
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kept outside of the zone and is prevented from entering the zone and from remaining
within the zone once it has entered- The clean zone must of course be backed up with
good housingkeeping practices which will not be explained in detail here.
In the arrangement shown in Figure 3, the zone is effectively a "reverse
clean zone" in which the machine 71 is of a type which generates high levels of dust,
for example a paper cutting machine or a textile spinning machine. In this case the
machine itself is surrounded by a zone which protects the remainder of the building
from receiving the high quantities of dust generated by the machine itself. In this way
instead of maintaining the whole of the building cleaned, it is only necessary to clean
the area surrounding the machine concerned so that the dust from that machine isprevented from escaping to the remainder of the building and is also contained within
that area by the action of the negative ions in the dust particles and the tendency to
precipitate and thus to collect on the ground surtaces from which they can be readily
removed by normal housekeeping systems.
The emitters are entirely Sree from any forced air et`fect so that neither
the ions nor any particle laden air passes thro~lgh a filter. Thus the negatively charged
ions collect onto the particles causing them to conglomerate and to precipitate onto the
floor. The floor thus acts as a collector tor the particles and this can be readily cleaned
by conventional housekeeping practices. In addition, the tendancy of the particles at
the area above the machine is to rise so that the bombardment of the particles in the air
space of the canopy with the ions causes the particles to tend to flow outwards of the
machine and to precipitate out onto the floor at the sides of the machine.
The details of the electrical equipment generating the high voltage are
not shown as these are well known to one skilled in the act. In addition the wiring
connections and the necessary conduit are not shown.
As an alternative arrangement tor ~Ise in some b~lilding structures, the
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emitter 25 can be used at the exit no~zle of the ventilation duct work so that the ions
are directed into the air stream which passes through the nozzle as the air emerges from
the nozzle and is communicated into the b-lilding. The use of the emitters in the
elongate or strip form enables the emitters to be tailored to the specific nozzles
concerned by simply cutting to length or selection from a number of available lengths
and attachment at the nozzle.
Turning now to Figure 8, there is shown a canopy arrangement similar
to that of Figure 3 including the so~lrce 71 mounted llpon the floor surface 70 and
including a canopy generally indicated at 82. The canopy is again formed including a
ceiling portion 83 and depending side walls 84 arranged aroulld the periphery of the
ceiling and depending theretrom to a position at a height from the floor sufficient to
allow persons and machinery to pass under without obstruction.
In this case the canopy is modified by the addition of two elements.
Firstly the ion emitters of the type generally described above are
provided in six rows indicated at 85, 86, 87, 88, 89 and 90. The two central rows 87
and 88 positioned above the row 71 are arranged instead of the previously described
negative ion emitters to provide emission ot positive ions. The construction of the
device is substantially identical to that previously described but the electrical controls
provide a positive voltage for emission of the positive ions trom the fibrous conductors.
Outside of the vertical area above the source are provided the rows 85,
86 and 89, 90 positioned closely adjacent the sides of the rectangular canopy. These
emitters are of the negative ion type previously described.
In addition two further rows of emitters 91 and 92 are provided located
at a position approximately halfway down the side walls 84 trom a ceiling to the floor.
In a practical example, the canopy can have a ceiling height of twenty feet in which
case the rows 91 and 92 will be positioned at a distance of approximately ten feet from
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the ground. The lowermost edge of the side walls is then positioned approximately six
and one half feet from the around to allow ready clearance. The emitters 91 and 92 are
arranged to emit negative ions.
This arrangement of the emitters tends to generate a flow of the particles
indicated by the arrows 93 in which the particles rise from the source 71, move
outwardly under the canopy and then precipitate downwardly toward the floor adjacent
the sides of the canopy. This tendancy is enhanced by the positive ion emitters at the
central area and in addition the tendancy of the air to rise over the source in view of the
fact that the source tends to generate heat and air flow due to various moving pacts.
The shape of the canopy and the location of the negative ion emitters then tends to turn
the particles to move outwardly and downwardly for precipitation downwardly toward
the floor 70.
To provide an additional collection of the particles, these is provided a
pair of collection surfaces 94 and 95 each arranged along a respective longitudinal side
edge of the canopy. &ch collection surface comprises a simple shelf type elementextending outwardly and connected from the lower most edge and inclined upwardlytherefrom and inwardly of the canopy to define between the wall 84 and the shelfelement a V-shaped area in which the particles tend to collect. The negative ionemitters 91, 92 positioned just above the shelf element also assist in the collection of
the particles in that area.
Automatic extraction devices may be provided in the V-shaped area for
continual removal of the particles collecting in that area. For example vacuum
arrangements may provide along the length of the collection zone for extraction of the
particles as they precipitate into the V-shaped area.
In a further modification of the emitters (not shown), each emitter is
formed as a module in which the electrical supply unit for the module is connected to
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the end of the channel section forming the emitter. In this case the channel section
forming in the emitter from which the electrodes protmde can have a length of the
order of the eight feet and be directly connected to its own electrical supply and control
unit. The modules can then be suspended from the ceiling of the canopy with a number
and arrangement of the modules being selected according to design requirements. This
arrangement has the advantage that the wiring necessary t`or insulation can now be
provided by the conventional electrical supply system at conventional voltages within
the building and is no longer necessary to provide high voltage wiring which requires
different safety constructions.
Turning now particularly to Figures 9, 10 and 11, there is shown an
alternative system of emitter. In Figure 15 the whole system is shown and comprises a
high voltage generator 100 which provides a high voltage on an output cable 101 for
communication to the various conductors of the emitters indicated at 102. Each of the
emitters is of the type shown in Figures 9, 10 and 11. In order to meet requiredelectrical codes, the high voltage cable 101 is received within a conduit systemincluding conduit elements 103, T com1ections 104 and angle connections 105. Thesystem further includes an air blower 106 providing high pressure air along a conduit
portion 107 for injection along the line of an arrow 108 into the conduit system at one
of the T fittings 104.
One portion of the conduit is shown in Figure 9 and comprises simply a
portion of conventional PVC tube which is circular in cross section and forms anextruded tube and is readily commercially available for an electrical conduit. The cable
101 thus extends along the length of the conduit.
The emitter 102 is similarly tormed from a length of PVC conduit
material which again is in the form of an extruded tube thus forming a peripheral wall
109 which surrounds a hollow interior 110. A tirst conductor 111 extends along the
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hollow interior 110 so that the conductor is housed within the hollow interior and is
thus confined by the electrically insulating peripheral wall 109. The first conductor
111 is also electrically insulated as indicated at 180. The circular cylindrical peripheral
wall is however drilled to form a first opening 112 and a plurality of openings 113 with
the openings 113 being arranged at spaced positions along the length of the tube.
The tubular emitter body 109 is connected to the tubular conduit 103 by
a connector 120. The connector includes a first cylindrical portion 121 defining an
outer surface which is a sliding flt within the conduit 103 so that it can be pressed into
the conduit. The connector further defines a cylindrical portion 122 which is shaped to
act as a press fit within the interior surface of the emitter body 109. An intervening
flange member 123 projects outwardly from the portion 121 and defines thus on one
side a shoulder 124 for engaging the end of the conduit and on the other side a shoulder
125 for engaging the end of the emitter body. The emitter body can thus be connected
to the conduit simply by pressing each onto the end of the connector element 120. A
sealing ring 126 is provided outside the end of the emitter body and abutting the
shoulder 125 to prevent or reduce the escape of air from the interior of the emitter
body.
A hollow bore 127 is provided through the connector element 120 to
allow the transmission of air from the interior of the conduit 103 into the emitter body.
In this way as shown in Figure lS the conduits and the emitter body themselves act to
transport air from the blower 106 into the emitter bodies for ejection through the
openings 112, 113 as shown by the arrows 128 in Figure lS. The air thus generated
by the blower 106 provides an air flow in a direction away from the emitter bodies to
assist in carrying the ions thus generated by the conductor away from the emitter bodies
to increase ion generation and to provide fresh air into the system. The blower 106
may be connected to a fine filtration system so that the air supplied to the system is
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particle free.
The connector element 120 also carries an electrical connector 130 which
carries a socket 131 at one end for connection to a male coupling at the end of the cable
101. Electrically connected to the socket (not shown) is a connector member 114 to
which an end of the conductor 111 is attached. A nut 115 clamps the connector
element 130 into the bore of the connector member 120.
The high voltage supplied to the connector 114 and connected to the first
conductor 111 is also supplied to a second conductor 181 and third conductor 182which are connected together with the connector 111 at the end 114. This connection
is obtained by a intimate wrapping of the first, second and third conductors at the
connector 114 together with a wrapping metal wire wrapped or braided around the
connecting conductors, all of which is encased with a heat shrink insulating wrapping
material.
The conductors 181 and 182 are formed of a carbon fiber fibrous yarn
arrangement previously described. The second and third conductors extend through the
hole at 112 to the exterior of the tubular support 109. On the exterior surface, the
conductors 181 and 182 are carried on a plurality of spaced support pins 183 mounted
on the surface of the support tube and extending radially outwardly therefrom. The
pins have a diameter at a reduced waist portion 184 of the order of 1/4 to 1/2 inch and
preferably of the order of 5/16 inch. The conductors emerging from the opening 112
are firstly wrapped around the adjacent pin 183 at the waist portion and then are carried
by the pin to the next pin each on a respective side of the pins so that the conductors
181 and 182 extend in parallel lines from each pin to the next with the conductors being
wrapped around the waist portion at each pin to provide a tensioning or capstan effect.
Thus the conductors are supported at a position spaced outwardly from the outer
surface of the support tube and are held in parallel relationship at a spacing of the order
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of 5/16 inch.
At the opposed end (not shown) of the support tube, there is a provided
a similar connection between the second and third conductors which pass through a
further opening into the interior of the support tube and are then connected to the
opposed end of the first conductor 111.
This arrangement has been found to provide a high level of ion emission
which is consistent along the length of the conductors. The additional first conductor
111 which is insulated and retained within the tubular support acts as a stabilizing
conductor to ensure consistent ion emission along the length of the second and third
conductors. The second and third conductors are supported away from the support tube
so that the full exterior surface of each conductor is available for the emission of ions.
The provision of more than one conductor and preferably the two conductors as shown
has been found to provide an increased ion emission effect. The air flow generated by
the air flow through the outlet holes 113 also assist in carrying the ions away from the
support tube.
In figure 12 is shown a similar arrangement including the support tube
109, the first conductor 111, the second and third conductors 181 and 182 and the air
discharge openings 113. In this arrangement however the support pins have been
replaced by support blocks 186 attached to the outside surface of the support tube 109
and thus defining a planar surface spaced outwardly from the support tube with the
planar surface Iying in a common planar surface which is common to all of the support
blocks 186. The conductors 181 and 182 are then laid across the common planar
surfaces of the support blocks and are attached thereto so that the conductors are
supported in the above described parallel space relationships supported away from the
outside surfaces of support tube 109. The support blocks 186 are attached to side wall
elements 187 and 188 which stand outwardly from the support tube 109 and thus define
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a channel surrounding and confining the conductors 181, 182 and the outer openings
113. This channel acts to assist in directing the ions movement away from the support
tube along with the air flow which is generated from the outlet opening 113. Thedevice therefore acts as a "air knife" in which a sheet of moving air and ions is
generated Iying in an axial plane of the support tube 109.
In Figures 13 and 14 is shown an alternative arrangement of emitter.
The emitter comprises an emitter body generally indicated at 150 which can be used in
the system of Figure 15 to replace the emitter body 109. In this construction there is
provided a cylindrical wall 151 which surrounds a hollow interior 152 for the
transmission of air and the release of that air through openings 153. In this
embodiment the wall 150 instead of being formed wholly from extruded PVC, includes
an embedded metallic foil layer 154 which is of circular cylindrical shape and is
recessed from the outer surface 155 of the wall and also from an inside surface 156 so
that it is electrically isolated. In this case the conductor comprises the metallic foil
layer 154 together with a plurality of pins 160 which are fixed in place by penetMtion
through the wall 151 so as to project outwardly from the outer surface 155. The
penetration of the needle 160 through the wall punches the metallic foil layer and
brings the needle into electrical connection with the metallic foil layer thus forming the
needle into part of the conductor. The needle has a sharpened outer end 161 which acts
as an effective emitter. This type of construction can be used in places where the
needle type emitter is preferred and can simply replace the emitter body 109 in the
collection of components necessary for forming the emitter system.
The emitter body as shown in Figures 9 and 10 is of circular cross
section as such tubular piping is readily commercially available. However other
custom cross sectional shapes are possible and can be designed to provide a particular
presentation surface for the front face of the emitter body for supporting the emitter
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conductor.
In a further arrangement, the fibrous conductor is mounted on the
emitter body so that it is supported away from the emitter body by a plurality of raised
support elements positioned at spaced locations along the length of the emitter body.
Thus the fibrous conductor passes through a first opening in the emitter body to be
presented at the front face of the emitter body and then extends along the length of the
emitter body at the front face and is supported away from the front face by a plurality
of raised support elements. The full periphery of the fibrous conductor is thus
accessible to the air to release ions from the full periphery and to allow air movement
around the full periphery.
Turning now to Figure 16 there is shown an alternative arrangement of
emitter comprising an emitter body 225 in the form of a tubular pipe. A metal
conductor 226 is mounted on the emitter body and comprises an elongate rod of
sufficient stiffness to be self-supporting between ends 227 and 228 of the rod so the rod
is carried by the emitter body 225 at a position just spaced from the outside surface of
the emitter body. The ends 227 and 228 are connected so as to pass through the
peripheral wall of the tubular emitter body into the interior for connection to the high
voltage supplied by an electrical conductor within the emitter body, the details of which
are not shown and the coupling of which to the conduit and to the connector is of type
previously described. In Figure 16, the emitter element for emitting the ions comprises
a fibrous conductor 229 attached to and carried by the rod 226 so that it is supported
along the length of the emitter body by the rod. The fibrous conductor is relatively
loose, soft and flexible and accordingly is attached to the rod 226 by a plurality of
crimped members 230 of the type conventionally used in electrical connections.
Thus the emitter element provided by the fibrous conductor is supported
by the emitter bcdy but is held at a position allowing access by the air to a significant
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portion of the emitter element 229 to generate a maximum number of ions.
A further modification is shown in Figure 16 in which an edge cleaning
nozzle 231 is mounted on the emitter body and provides an air jet of high velocity for
transmission along the length of the emitter element 229 to provide a cleaning action
thus removing any collected dust or other particles which could interfere with the
generation of ions. This obviates the necessity for regular brushing or cleaning of the
emitter elements since the device can be timed and arMnged to provide a periodic jet
blast of air across the emitter element. In the embodiment shown, the jet 231 issupplied with the high pressure air t`rom the interior ot the tubular member 225,
however a separate supply may be provided from a separate duct so the interior of the
tube can be used to supply air flow for transporting the ions, for example through a slot
longitudinally of the front face and just behind the rod 226.
In Figure 17 is shown a further arrangement including an emitter support
member 232 which in this case is in the form of a flat bar other shapes of support
member are also possible which may or may not comprise ducts for communication of
air therealong and for defining a housing for part of the electrical conductor. In this
case the member 232 is solid. The member carries a rod 233 supported on ends one of
which is visible at 234 holding the rod away from the bar 232. Upon the rod is
mounted a plurality of emitter elements one of which is indicated at 235 and a second
which is indicated at 236. For convenience of illustration the two different types are
mounted on the same rod 233 but in practice generally a single type will be used in a
particular circumstance. The emitter element 235 comprises a plurality of pins 237
projecting outwardly from a central collar 238 mounted upon the rod 233. The pins
defining pointed ends from which the ions are preferentially emitted.
The emitter element 236 comprises a disc which is formed from pressed
steel and defines a sharpened outer edge 239 trom whicll the ions are preferentially
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emitted. The disc thus provides an edge aroulld the full periphery thus increasing the
availability for ion emission.
In Figure 14 is shown a further example of emitter element which
comprises an elongate needle portion 170 to which is attached a clamping collar 171
which receives a plurality of loops 172 of the conductive fibrous material described
previously. The loops project outwardly from the clamping collar 171 and are spread
apart by the normal resilience of the fibrous material. The conductive pin 170
communicates with the electrical supply, in this case the layer 154 and communicates
the high voltage to the fibrous conductor tor emission of the ions.
The emitter element of the type shown hl Figure 14 can have the
advantage that it is readily flexible allowing it to be formed into a curved or circle to
follow the contours of a required location. This curvature can be achieved by flexing
the element due to the flexibility of the plastics insulating material and the flexibility of
the foil layer without fracturing the foil layer.
Turning now to Figure 18 there is shown a further embodiment in which
the emitter element is generally indicated at 275 can be rotated to obtain movement of
the emitter conductive portion 276 to cause relative movement between the conductive
element and the air. In the embodiment shown, the emitter elements 275 project
radially outwardly from a hub 277 which includes a fixed portion 278 for attachment to
a fixed structure and a rotating portion 279 carrying the elements 275 which rotate
about a vertical axis centrally of the hub 277. The hub includes a slip ring by which
the electrical connection is maintained t`rom a high voltage source connected to the
stationary portion 278 for communication to the rotating portion 279.
In an alternative arrangement, the emitter elements can be of the tubular
type described above and rotated about a longitudinal axis of the tublllar element.
Since various modifications can be made in my invention as hereinabove
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described, and many apparently widely ditferent embodiments of same made within the
spirit and scope of the claims without departing trom such spirit and scope, it is
intended that all matter contained in the accompanying specification shall be interpreted
as illustrative only and not in a limiting sense.
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