Note: Descriptions are shown in the official language in which they were submitted.
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This invention provides a method for cleaning air supplied to an operator-
protection or motor vehicle cabin, wherein a housing communicates with said cabin,
a means is used to induce a flow of air through said housing into said cabin, atleast one chemisorption filter is used through which the flow of air in said
housing transverscs, and at least one heating device is disposed upstream of said
filter in the path of at least part of the air flow to be cleaned, to heat all or
part of said air flow.
It is known to incorporate dust filters in the fresh air inlet ducts in
motor-vehicle cabins. Although these filters retain any dust carried along in the
air, they cannot meet the requirements of active protection of the occupants of
the cabin against pollutants contained in the air. In the case of high density
traffic in particular~ the air drawn into the cabin contains, among other things,
hydrocarbon (~IC) compounds, nitrogen oxides (N0x), acid gases, for example sulphur
dioxide, and other sulphur compounds, carbondioxide and carbon monoxide. Although
it is known that pollutants of this kind may be removed from the air with chemi-sorption compounds, the use of these in connection with the supply of fresh air
to motor-vehicle cabins has always been limited by the complex design and the
cost involved. The same applies to operator-protection cabins, into which
polluted air may also enter.
The p~esent invention seeks to eliminate the above-mentioned disadvant-
ages and to provide a method and an apparatus of the type mentioned at the begin-
ning thereof which will provide simple and effective cleaning of the air supplied
and, at the same time, a long service-life for the chemisorption and/or catalystcompounds used in the filters.
This may be achieved by heating all or part of the air to be cleaned
and then passing it to the ~ilter or filters. Preheating the flow, or flows,
or air, prevents moisture from being deposited onto the filters, such moisture
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having a very negative effect upon the action of the chemisorption and/or
catalyst compounds. It is known that some chemisorption or catalyst compounds
for example those used to convert C0 into C02~ or for separating N0X and
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hydrocarbon compounds, are very negatively affected by moisture.
According to one aspect of the invention the filter unit as a whole
is arranged so that it does not lie within the natural flow of the fresh
air, and that the air is drawn in at a location remote from the normal air
intake which is usually at the front of the vehicle; this involves deflecting
the flow of air, as a result of which the water droplets are not drawn into
the filter because of the low suction velocity.
According to another aspect of the invention, in which the built-in
filter used to separate N0x, HC and C0 is regenerated in situ, some of the
air drawn in flushes the chemisorption filter by means of a duct and a fan,
thus regenerating and reactivating the chemisorption compounds and driving
the moisture out of, for example, the silica-gel and C0 catalysts. Some of the
air drawn in (outside air, preferably heated, may be used)may be used to reverse-
flush the chemisorption filter, preferably without interrupting the flow of
fresh air to the cabin.
In the case of operator-protection or motor-vehicle cabin filters
it is known to use hopcalite compounds f.or separating C0; however, as air
polluted with C0 flows therethrough, the hopcalite usually absorbs moisture
which destroys its separating ability.
In order to keep the hopcalite active, for the purpose of separating
CO rom areas where men are at work, it is proposed, according to the
invention, to adjust the water vapour pressure of the air to above the point
at which moisture is picked up by the hopcalite and therefore by the absorption-
layer and/or any additional chemisorption layers used to eliminate N0x and HC
compounds.
The above adjustment may be achieved by heating the chemisorption
compounds, e.g. hopcalite. In certain cases, this involves a temperature of
,
about 50C. }lowever, such a temperature is unsuitable for a human environment.
In order to avoid this, the apparatus may be arranged so tha-t the in-
flowing air to be cleaned is heated by the unit, along and/or with the chemisorp-
tion compounds or the like, and the ascending heated air is cooled down again by
the refrigerating capacity of the unit, from 50 to 30C, for example, depending
on the efficiency of the unit.
This method ensures that the chemisorption compounds, or the like, have
longer service-lives and, that the clean air returns to the circuit at a low
temperature.
According to one embodiment of the invention, the incoming air to be
cleaned, is passed at its natural temperature, through chemisorption and filter-
compounds, in order to eliminate acid gases, hydrocarbons, and solids such as
dust etc., and only then is the air heated to such an extent that the water
vapour pressure is sufficiently above the moisture pick-up point of the subsequent
catalyst compounds used to convert C0 into C02. The air, freed from pollutants
after flowing through the catalyst compounds, is then fed to a cooling zone which
cools it down for use in the cabin.
According to a further aspect of the invention, there is provided an
apparatus for purifying the air fed to an operator-protection or motor vehicle
cabin, said apparatus comprising a housing communicati.ng with said cabin, means
for inducing a flow of air through said housing and from said housing into said
cabin, at least one chemisorption filter in said housing traversed by said flow,
and at least one heating device disposed in the path of at least part of the air
flow to be purified upstream of said filter.
The invention will be further described with reference to the accompany-
ing drawings showing, by way of example, preferred embodiments of the
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invention, in which:
Figure 1 shows a partly cut away side elevation of a motor vehicle
using an apparatus according to the invention;
Figure 2 is a diagrammatic representation of a part of an apparatus
according to the invention;
Figure 3 is a view of another design of an apparatus according to
the invention;
Figure 4 is a diagrammatic representation of another design
according to the invention,
Figure 5 is a diagrammatic representation of another design according
to the invention;
Figure 6 is a partly cut away side elevation of a motor vehicle with
an apparatus according to the invention;
Figure 7 is a diagrammatic representation of another design according
to the invention;
Figure ~ is a diagrammatic representation of another design according
to the invention;
Figure 9 is a side elevation of the rear end of a motor vehicle with
an apparatus according to the invention;
Figure 10 is a diagrammatic side elevation of the rear seat of a
motor vehicle;
Figure 11 is a view of the head-rests of two adjacent rear seats
according to Figure 10;
Figure 12 is a side elevation of the rear seat of a motor vehicle; and
Figure 13 is a partly cut away side elevation of a motor vehicle
with an apparatus according to the invention.
In the embodiment shown in Figures 1 and 2, 1 represents the trunk of
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a motor vehîcle containing a chemisorption filter pa~k 2. The latter
preferably consists of tubular elements which are inserted one into the other,
are preferably double-walled, and are f;tted with webs to limit, or prevent
displacement of the chemisorption or catalyst compounds which it contains.
Air intake pipe 3 is located in a protected area at the rear of the vehicle.
Heater 4 is located at the inlet end and fan 5 at the outlet end of the filter.
The chemisorption filter itself is marked 6, the filter tubes, inserted one
into the other, being filled with different compounds, for example. Located
near the outlet end is another heater 7. Air line 8 serves to carry air from
the rear into the motor-vehicle cabin. Ventilation of the passenger com-
partment may be effected from the rear, for example, or laterally, or from
behind the rear head-rests, as indicated by arrow 9. Located on the dashboard
of the vehicle is a congestion or smog key 10 which is switched on in the
event of heavy pollution by other vehicles. 11 is a waste air outlet through
which part of the recirculated air may escape from the passenger compartment.
As a result of arranging the chemisorption filter, for example in
the trunk or in the vicinity of the rear seat, there is no need to increase
the size of the usually very restricted engine compartment. Incorporation of
the chemisorption filter into the engine hood area may interfere with the
configuration of the vehicle, thus affecting streamlining.
According to the invention, ventilation is controlled sothat by
actuating a key, known as a smog or congested traf~ic key, air no longer
enters the vehicle through the conventional inlet ducts; nor, as in certain
types of vehicle, is the supply of air from the outside shut off, i.e. the
air already in the vehicle, possibly heated or cooled by an air-conditioning
unit, being merely recirculated, thus becoming intolerable to the occupants.
Instead, a certain amount of air enters through air inlet3c~dpasses through
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chemisorption pack 2 into the interior of the vehicle, as shown at 9, or
through air line 8, so that fresh air, -free from pollutants, is supplied to
the occupants, while an amount of air, corresponding approximately to the
amount of clean air thus supplied, escapes from the interior of the vehicle
through waste-air outlet 11. The air is heated appropriately by heater 4,
so that little moisture reaches ~he chemisorption filter compounds or
catalyst compounds.
The direction of rotation of fan 5 can be reversed. Thus when smog
key 10 is actuated in a certain way, the fan draws air from the interior of
the vehicle. This air, used to regenerate filter 6, is preferably heated to
a very high temperature, 60C or more, for example. As compared with the
ventilating phase, fan 5 provides only a small amount of air in the reverse
direction for regenerating filter 6.
The type of ventilation provided by the invention makes it possible
for the vehicle to be ventilated conventionally in the absence of traffic
congestion. In city traffic, or congested highway traffic, air may be injected
into the passenger compartment -through the chemisorption filter. When filtra-
tion is not needed, the filter may be regenerated. This ensures that the
filter will have a very long service life since, in normal passenger-vehicle
use, only 10 to 20% of driving time is spent under congested or city traffic
conditions.
In this design, ventilation of motor vehicle cabins is carried out
in such a ma~mer that, under congested traffic conditions, the normal supply
of fresh air is shut off, the desired cold or warm air being circulated, and
chemically cleaned air being pumped into the passenger compartment. A required
amount of recirculating air escapes from the compartment and the occupants
are constantly supplied with fresh air.
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In the design according to Figure 3, 21 is the unfiltered fresh air
supply. Arranged in the approximately ~-shaped tubular part is a control
flap 22 which admits either unfiltered fresh air or causes the supply of
fresh air to pass through chemisorption filter 25. Fan 23 passes the air,
in the direction of arrow 24, into the passenger-compartment and passes
flushing air, in the direction of arrow 26, for the regeneration of the
chemisorption filter 25. Control flap 27 makes it possible to use fresh air
only or hot air to regenerate and activate chemisorption filter 25. The
j hot air is introduced through a line 28.
The ventilation system is connected to a normal fan or air-
conditioning unit in such a manner that the air drawn in is made directly
available without passing through the chemisorption filter or, under city
traffic or congested traffic conditions, is passed at will through filter 25.
In the design according to Figure 4~ 31 indicates the inflowing air
and 32 the chemisorption-filter pack preceded by a heating and cooling
device 33, preferably in the form of a Pelletier element. The heating and
cooling device comprises cooling ribs 34 arranged in the air outlet duct 36.
~leating ribs 35 are provided in air inlet duct 31. This arrangement produces
considerable heating of the chemisorption compound, thus preventing the
depositing of moisture from the air flowing therethrough. So that the cleaned
air will not be too hot, the devices for heating the chemisorption compounds,
or the like are incorporated into the system as a whole in such a malmer
that the inflowing air to be cleaned is heated by the unit alone or with
the chemisorption compounds or the like, while the outflowing air is cooled
by the refrigerating action of the unit, thus providing a drop in temperature
from 50 to 30C
In the design according to Figure 5, only air or compounds which are
to convert C0 catalytically into C02 are heated, in order to reduce the amount
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of heating required.
In this figure, 41 indicates the incoming polluted air which passes
through chemisorption compounds 42 in order to eliminate acid gases such as
S02, NOX and hydrocarbons, for example, and also solid pollutants in the form
of dust. Duct 43 acts as the receiver for pre-cleaned gas which is fed to
heating surface 44, for example heated ribs. The preheated gas passes
thence through catalyst layer 45, consisting of hopcalite, for example,
where C0 is converted into C02. Clean, breathable air 46, emerging from
catalyst layer 45 and still hot, is passed through ribs 47 for cooling and
for subsequent use as breathable air. 48 indicates a combined heating and
cooling unit, one end of which heats up the precleaned air by means of
heating surfaces 44, while the other end cools the air down by cooling ribs
47. A conventional Pelletier element may be used for this purpose.
The incoming air, containing pollutants, is first forced or drawn
through the chemisorption compounds in order to eliminate acid gases, solid
substances and llydrocarbons. It is then heated until the water vapour
pressure of the air is above the moisture absorption point of the catalyst,
passed through the catalyst and then cooled down. Thus, during summer
operation, this unit may also be used to provide air-conditioning. The air
is preferably heated to about 50C, so that the catalyst does not become
inactivated by mois-ture absorption as the air flows therethrcugh.
It is known that sunny, rainy, foggy and cold weather greatly affect
the humidity of the incoming air. The degree to which chemisorption compounds
are sensitive to moisture absorption differs considerably, the C0 catalyst, in
particular, being highly sensitive to moisture, so that chemisorption declines
very sharply even when a small amount of moisture is absorbed.
In order to exclude almost completely the absorption of moisture,
the housing of the chemisorption filter according to Figure 6 is encapsulated
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and located in the natural heating area of the engine.
This ensures that the incoming air is heated to a grea~er or lesser
degree, depending upon the design, thus preventing the release of moisture
to the chemisorption compounds, and ensuring that chemisorption is not
affected by atmospheric humidity. Furthermore, after the engine has been
switched off, radiation ensures that the filter housing and chemisorption
compounds are constantly subjected to a drying and regenerating process, so
that the said compounds are completely dry and active whenever the vehicle
begins a new journey. This arrangement eliminates the need for any external
energy in the form of heaters or heater-coils requiring additional powerJ
reducing engine performance, and thus increasing costs. The natural heating
obtained by locating the encapsulated filtering device in the heated
vicinity of the engine is sufficient to increase the service life of the
chemisorption filter by a multiple, thus making this arrangement an economi-
cal proposition.
Figure ~'5 illustrates a motorized passenger-venicle comprising an
encapsulated filter 53 in engine-bay 52, the supply of fresh air being indicated
by arrow 5~1. Arrow 55 indicates the flow of cleaned air, through the filter,
hec~ted by engine-heat, to the interior of the vehicle.
During hot summer weather, the fact that the air is heated by between
l and 2C, for example, is unimportant, whereas in winter weather it may even
be desirable. In this design, encapsulated filter-media, not affected by
engine odour or exhaust gas, are fitted in the area subjected to waste heat
from the engine, the said filter-media being replaceable in layer form and
being supplied with fresh air from outside the engine-bay. Since this air
is heated to some extent, it contains less moisture as it flows through the
chemisorption compounds and emerges as clean air for use by the occupants of
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the passenger compartment.
In the design according to Figure 7, only an advance moisture-
absorption layer is regenerated and only a small volume of air ;s heated to
a very high temperature. This air expels the moisture and is exhausted to
atmosphere by means of a fan. This makes it possible to keep the amount of
energy required for heating very small. In order to prevent the fan from
being damaged by the high temperatures, the design thereof is such that,
cluring regeneration, it draws in secondary air with the hot primary air.
This cools the air sufficiently to prevent the fan from being damaged. In
this design, 61 is the complete chemisorption filter and 62 indicates the
multi-layer chemisorption compounds preceded by a drying layer 63 serving to
absorb moisture. Reversible fan 64 injects more air into the chemisorption
filter than it draws out when it rotates in the opposite direction. Arrows
65 indicate the large volume of air forced through chemisorption filter 62
for ventilating the cabin, while arrows 66 indicate the substantially smaller
volume of air drawn out of the cabin and heated, preferably by a heater-
coil 68, to such an extent that it carries the moisture from drying layer
63 to fan 64. Opening 67 ensures that cool air is also drawn in to ensure
that fan 64 does not become unduly hot.
Advance drying layer 63, which is heated separately by heater-coil
68 supplied from the battery and/or the lighting generator, ensures that
the small amount of heat provided merely regenerates advance drying layer
63. In this arrangement the chemisorption and catalyst compounds 62 need
not be heated to the high temperature sufficicnt to regenerate the drying
layer, for example to above 90C, i.e. it i5 not necessary to heat up volume
66 of regenerating air.
In this design, a separate drying layer 63 is provided in front of
the cllemisorption and catalyst compounds. Heater-coil 68 serves, on the one
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hand to heat up the incoming fresh air as desired, for example to 20 or 30C
and, on the other hand, when fan 64 is rotating in the opposite direction,
to heat up the small amount of air required during the regenerating phase,
in such a manner as to expel the moisture.
The design according to Figure 8 is a further development of that in
Figure 7. In order to avoid, during the regenerating phase, having to draw
the moist air from the cabin, through the chemisorption and catalyst compounds,
for heating and subsequently regenerating the drying layer, a secondary air
flap 79 is provided. In Figure 8, 71 indicates the complete chemisorption
and catalyst filter, while 72 indicates the multilayer chemisorption and
catalyst compounds. These precede drying layer 73 used to absorb moisture.
Reversible fan 74 injects more air into the filter than is drawn out during
the regenerating phase. Arrows 75 indicate the amount of air drawn through
the filter to ventilate the cabin. The substantlally smaller amount of
secondary air 76, drawn from the cabin and made very hot by heater 78, flows
through drying layer 73 from the rear, the moisture from this layer being
carried away by fan 74. Cooling air may be drawn in through aperture 77,
so that fan 74 does not become unduly hot.
Depending upon its location, secondary air flap 79 makes it possible
to draw in secondary air 76 in front of chemisorption and catalyst compounds
72. This air then passes, without releasing its moisture, to heater 78.
Thus heated, it regenerates drying layer 73. With this design, moist air
need not be drawn, during the regenerating phase, through filter compounds 72.
Instead, secondary air 76 is drawn in, beside the filter compounds, through
flap 79 and heater 78 for the regeneration of drying layer 73. The drying
and filtering compounds, and the supply of secondary air, may all be preceded
by a dust filter, e.g. a felt filter, in order to eliminate foreign substances,
such as dust from the compounds.
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Figure 9 illustrates a design in ~hich the filter device is arranged
in the trunk of a motor vehicle, so that provision oF an air inlet requires
no external changes to the vehicle, inlet aperture 81 being located at the
back of the trunk, behind the licence plate 82. Located between the trunk
and the licence plate are spacers 83, so that air, indicated by arrow 84 can
enter unimpededly and, as far as persons outside are concerned, unseen behind
the licence plate into the trunk, passing through hoses therein to the
filter device, and thence to the passenger compartment.
Figures 10 to 12 illustrate designs in which, instead of the filter
devices being arranged in the trunk or engine-bay of the vehicle, use is made
of the seat head rests, preferably those of the rear seat, for cleaning the
air. The design may use individual or dual head rests, the outer shell being
well upholstered in the area supportin~ the occupant's head.
The head rests on the rear seat of the vehicle are marked 91 and are
connected to suction lines 92. Arrows 93 indicate the flow of clean air to
the passenger compartment. Outlet line 94 is used for regeneration of the
chemisorption compo~mds, not shown. Fan 100 is situated in the trunk, in
order to keep tlle noise near the head rests as low as possible. In Figure 11,
fan 95 is arranged centrally between head rests 96,97, but additional fans
98,99 may also be arranged externally of the head rests. The head rests have
ample upholstering as a protection against impact.
In the design according to Figure 12, the rear surface of head rest
102 comprises air outlet apertures 101 facing towards the rear window. With
fan 95 arranged centrally between the head rests, ample protection against
impact is provided, with little danger of injury from the fan.
Figure 13 illustrates a particularly compact arrangement of the
filter device. In this case the device is located in the area behind the
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rear head rests, the so-called parcel area. In this way, the already
restricted trunk and engine-bay areas are not still further restricted.
In this figure, 111 indicates the passenger vehicle and 112 the
rear seat thereof. Filter 113 is located on the cover behind the rear seat
head rests, the so-called parcel area. Inlet line 114, preferably with a
built-in fan, runs rearwardly inside the trunk.
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