Note: Descriptions are shown in the official language in which they were submitted.
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Air Purification Device
Field of invention
The present invention relates to an air purification device. The present
invention more particularly relates to a portable air purification device.
Prior art
Population growth compounded with rapid urbanisation has amplified
the potential for bacteria and viruses to spread quickly. Accordingly,
there is an increasing need for purification and disinfection of air in
order to eliminate the risk of infecting vulnerable hospitalised people
and nursing home residents. The Coronavirus Disease COVID-19 has
brought the risk of infecting vulnerable older or hospitalised people as
well as nursing home residents with various diseases into focus.
Thus, there is a need for an air purification device that can reduce the
risk for infecting vulnerable people with viruses such as the Coronavirus
causing the Coronavirus Disease COVID-19.
Most viruses vary in diameter from 20 nm to 400 nm. Accordingly, even
though many prior art air purification devices comprise an efficiency
standard of air filter such as a high-efficiency particulate air (HEPA)
filter, these purification devices cannot effectively disinfect viruses due
to the small size of viruses. Accordingly, the prior art air purification
devices cannot be used to protect from airborne or aerosolised
pathogens.
Filters meeting the HEPA standard must remove from the air that
passes through the filter at least 99.95% (European Standard) or
99.97% (ASME, U.S. DOE), respectively, of particles whose diameter is
equal to 0.3 pm.
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It is an object of the present invention to provide an air purification
device that can efficiently purify virus containing air and thus reduce
the risk for infecting vulnerable people with viruses that cause infectious
diseases.
Summary of the invention
The object of the present invention can be achieved by a purification
unit as defined in claim 1 and by a method as defined in claim 12.
Preferred embodiments are defined in the dependent subclaims,
explained in the following description and illustrated in the
accompanying drawings.
The purification device according to the invention is a purification device
for disinfecting and filtering intake air, wherein the purification device
comprises:
- a housing provided with a number of inlet perforations for allowing the
intake air to enter the housing and a number of air outlet perforations
for allowing air purified by the purification device to leave the housing;
- a fan arranged inside the housing to suck the intake air into the
housing and blow the purified air out of the housing;
- an ultraviolet radiation lamp arranged inside the housing to irradiate
the intake air;
- a high-efficiency particulate air (NEPA) filter surrounding the
ultraviolet radiation lamp and being arranged to filter the intake air
before the intake air leaves the housing as purified air, wherein the
filter comprises a plurality of pleats arranged in such a manner that the
angle between adjacent pleats is 30 degrees or less.
Due to the small acute angle e, the retention capability of the filter can
be increased. Therefore, the purification device provides a more
efficient purification of virus containing air. Accordingly, by using the
purification device to purify the air that vulnerable people is exposed to
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(e.g. in a hospital room or a room in a nursing home) it is possible to
reduce the risk for infecting vulnerable people with viruses that cause
infectious diseases.
In one embodiment, the angle between adjacent pleats is 28 degrees.
In one embodiment, the angle between adjacent pleats is 26 degrees.
In one embodiment, the angle between adjacent pleats is 24 degrees.
In one embodiment, the angle between adjacent pleats is 22 degrees.
In one embodiment, the angle between adjacent pleats is 20 degrees.
In one embodiment, the angle between adjacent pleats is 18 degrees.
In one embodiment, the angle between adjacent pleats is 16 degrees.
In one embodiment, the angle between adjacent pleats is 15 degrees.
In one embodiment, the angle between adjacent pleats is 14 degrees.
In one embodiment, the angle between adjacent pleats is 12 degrees.
In one embodiment, the angle between adjacent pleats is 10 degrees.
In one embodiment, the angle between adjacent pleats is 8 degrees or
less.
The number of pleats is inversely related to the angle between adjacent
pleats. Accordingly, it is possible to achieve a small angle between
adjacent pleats by applying a large number of pleats.
Moreover, the total filter area is proportional to the number of pleats.
Accordingly, it is possible to increase the total filter area by increasing
the number of pleats. It is an advantage to have a large filter area
because the filtering capacity (the maximum flow velocity) is
proportional to the filter area.
The small angle between adjacent pleats makes it possible to make the
virus stick to inside surface of the HEPA filter. Since the filter surrounds
the ultraviolet radiation lamp, there is plenty of time to eliminate the
virus by irradiating ultraviolet radiation. Accordingly, the purification
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unit has a unique ability to maintain virus particles inside the space
surrounded by the filter and irradiate the virus particles with ultraviolet
radiation that destroys the virus particles.
Since the filter does not allow any virus particles to pass the filter and
since any virus particles present at the inside surface of the filter is
killed by the ultraviolet radiation from the ultraviolet radiation lamp, the
filter contains no virus particles when the filter has to be replaced
(during maintenance). Accordingly, it is not required for service
personnel to wear a hazmat suit or biohazard suit when replacing the
filter. Moreover, service personnel can remove the filter without risking
infection and the filter will not contain any virus particles when the
purification device is turned off. Accordingly, it is safe to move the
purification device from one room to another.
The unique ability to maintain virus particles inside the space
surrounded by the filter and irradiate the virus particles with ultraviolet
radiation that destroys the virus particles provides a surprising increase
in efficiency. The testing protocols shows that the device can reduce the
number of viral airborne particles in a room by 99.98¨% after 15
minutes and after 30 minutes it is not possible to detect viral particles.
It can also be seen that the NEPA filter has a viral load below the
detection limit after 15 minutes,;:i as such the invention provides an
efficient way to ensure purification of an area, and to ensure safety of
personal performing maintenance.
In one embodiment, the distance from the UV lamp and the inside part
of the HEPA filer is less than 20_cnn.
In one embodiment, the distance from the UV lamp and the inside part
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of the HEPA filer is less than 18 cm.
In one embodiment, the distance from the UV lamp and the inside part
of the HEPA filer is less than 16 cm.
5
In one embodiment, the distance from the UV lamp and the inside part
of the HEPA filer is less than 14 cm.
In one embodiment, the housing is cylindrical.
In one embodiment, the housing is box-shaped.
In one embodiment, the HEPA filter area is 2 square meters or more.
In one embodiment, the HEPA filter area is 3 square meters or more.
In one embodiment, the HEPA filter area is 4 square meters or more.
In one embodiment, the lowest position of the UV lamp is the distal
portion of the UV lamp, wherein an air gap is provided between the
bottom plate of the housing and the distal portion of the UV lamp.
Hereby, shadow areas (non-irradiated intake air leaving the housing)
can be avoided. Moreover, particles that fall down to the bottom plate
of the housing will be exposed to UV irradiation from the UV lamp.
Accordingly, particles on the bottom plate will be destroyed by the UV
irradiation.
In one embodiment, the light irradiation portion of the UV lamp extends
vertically.
In one embodiment, the housing comprises a bottom portion and a top
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portion configured to be detachably attached to the bottom portion.
Hereby, access to the structures inside the housing is eased. This is an
advantage during maintenance and replacements.
In one embodiment, the fan is arranged in the top portion and the light
irradiation portion of the UV lamp is arranged in the bottom portion.
Hereby, it is possible to introduce intake air into the top portion of the
housing and blow the intake air into the bottom portion of the housing
and carry out an UV irradiation treatment of the air that is blown into
the bottom portion of the housing.
In one embodiment, the inlet perforations are provided in the top
portion, whereas the outlet perforations are provided in the bottom
portion. Hereby, it is possible to guide the intake air into the top portion
of the housing through the inlet perforations and blow the purified air
out of the bottom portion of the housing through outlet perforations.
Accordingly, the air flow pattern can be controlled in a simple and
reliable manner.
In one embodiment, the fan has a horizontally orientated intake portion
and a vertical output portion so that air pressurised by the fan leaves
the fan in a downwardly vertical direction. Since the intake air enters
the purification device in the top portion of the purification device, the
intake air will not suck particles from floor level into the purification
device. The purified air will leave the purification device in a lower level
than the level at which intake air enters the purification device.
Since the intake air enters the purification device in the top portion of
the purification device, which is more than 200 mm above floor level,
the purification device meets the requirements for being used in
Scandinavian hospitals, in which the floor zone and the zone extending
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200 mm above the floor are considered to be contaminated.
In one embodiment, the intake air enters the purification device in the
top portion of the purification device, which is more than 400 mm above
floor level.
Intake air enters the purification device in the top portion of the
purification device, which is in the range 500-700 mm above floor level.
In one embodiment, the height of the purification device is 60-100 cm.
In one embodiment, the height of the purification device is 70-90 cm.
In one embodiment, the height of the purification device is 75-85 cm
such as 80 cm.
In on embodiment, the purification device is cylindrical and has a
diameter in the range 30-55 cm.
In on embodiment, the purification device is cylindrical and has a
diameter in the range 35-50 cm.
In on embodiment, the purification device is cylindrical and has a
diameter in the range 40-45cm such as 42 cm.
In one embodiment, the fan is configured to deliver a flow up to 600
m3/hour.
In one embodiment, the fan is configured to deliver a flow up to 560
m3/hour.
In one embodiment, an additional layer is arranged at the outside of the
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filter.
In one embodiment, the additional layer comprises activated carbon.
It may be advantageous that an additional layer is sandwiched between
the housing and the filter, wherein the additional layer comprises
activated carbon. Hereby, the activated carbon can remove unwanted
odours by acting as an adsorbent which will trap the odour inside the
activated carbon and retain it. Moreover, the additional layer can
prevent UV light from escaping to the surroundings.
In one embodiment, the top portion comprises a coarse filter slidably
arranged in one or more filter tracks extending axially near the rim of
the top portion. Hereby, replacement of the coarse filter is eased.
In one embodiment, the top portion comprises two, three or four
separated filter segments constituting a coarse filter, wherein the filter
segments are slidably arranged in filter tracks extending axially near
the rim of the top portion.
In one embodiment, the top portion comprises four coarse filter
segments that are slidably arranged in filter tracks extending axially
near the rim of the top portion.
In one embodiment, the purification device comprises a particle sensor
arranged to detect the level of particles in the air.
In one embodiment, the particle sensor is arranged inside the housing.
Hereby, the particle sensor can detect the level of particles in the intake
air entering the housing.
In one embodiment, the particle sensor is arranged inside the top
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portion of the housing. Hereby, the particle sensor can detect the level
of particles in the intake air entering the top portion of the housing.
In one embodiment, the particle sensor is arranged inside the bottom
portion of the housing. Hereby, the particle sensor can detect the level
of particles in the intake air entering the bottom portion of the housing.
In one embodiment, the purification device comprises a smoke alarm.
Accordingly, the purification device can alert the people being in the
same room as the purification device in case of a fire.
In one embodiment, the smoke alarm is arranged inside the housing.
Hereby, the smoke alarm can detect the level of smoke in the intake air
entering the housing.
In one embodiment, the smoke alarm is arranged inside the top portion
of the housing. Hereby, the smoke alarm can detect the level of smoke
in the intake air entering the top portion of the housing.
In one embodiment, the smoke alarm is arranged inside the bottom
portion of the housing. Hereby, the smoke alarm can detect the level of
smoke in the intake air entering the bottom portion of the housing.
In one embodiment, the purification device comprises a control unit
configured to control the speed of the fan in dependence of the detected
level of particles in the air.
In one embodiment, the control unit is configured to control the speed
of the fan in dependence of measurements made by the smoke alarm.
In one embodiment, the control unit is configured to turn on the fan if
the particle content of the intake air exceeds the predefined level.
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In one embodiment, the control unit is configured to turn on the UV
lamp if the particle content of the intake air exceeds the predefined
level.
5 In one embodiment, the control unit is configured to turn on the fan
and the UV lamp if the particle content of the intake air exceeds the
predefined level.
In one embodiment, the control unit is configured to regulate the speed
10 of the fan in dependency of the detected level of particle content
(detected by the particle sensor).
In one embodiment, the control unit is configured to adjust the speed of
the fan to take one of two or more predefined non-zero levels.
In one embodiment, the control unit is configured to adjust the speed of
the fan to take one of three or more predefined non-zero levels.
In one embodiment, the control unit is configured to adjust the speed of
the fan in an ungraduated manner on the basis of the detected level of
particle content. This may be done by fitting the fan with a permanent
magnet motor and a frequency converter. This will furthermore allow
the provision of the lowest possible energy consumption.
In one embodiment, the predefined particle content level is a default
quantity. In another embodiment, however, the predefined particle
content level can be adjusted by using a control unit of the purification
device.
The method according to the invention is a method for disinfecting and
filtering intake air, wherein the method comprises the following steps:
- sucking intake air into a housing by means of a fan arranged inside
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the housing, wherein the intake air enters the housing through a
number of inlet perforations provided in the housing;
- blowing purified air by means of the fan out from the housing through
a number of air outlet perforations provided in the housing;
- irradiating the intake air by means of an ultraviolet radiation lamp
arranged inside the housing;
- filtering the intake air by means of a HEPA filter before the intake air
leaves the housing as purified air,
wherein the method comprises the step of applying a filter that
comprises a plurality of pleats arranged in such a manner that the angle
between adjacent pleats is 30 degrees or less.
Accordingly, the method provides a way of purifying the air that
vulnerable people is exposed to (e.g. in a hospital room or a room in a
nursing home) in an improved manner. Accordingly, the method makes
it possible to reduce the risk for infecting vulnerable people with viruses
that cause infectious diseases.
In one embodiment, the angle between adjacent pleats is 28 degrees.
In one embodiment, the angle between adjacent pleats is 26 degrees.
In one embodiment, the angle between adjacent pleats is 24 degrees.
In one embodiment, the angle between adjacent pleats is 22 degrees.
In one embodiment, the angle between adjacent pleats is 20 degrees.
In one embodiment, the angle between adjacent pleats is 18 degrees.
In one embodiment, the angle between adjacent pleats is 16 degrees.
In one embodiment, the angle between adjacent pleats is 15 degrees.
In one embodiment, the angle between adjacent pleats is 14 degrees.
In one embodiment, the angle between adjacent pleats is 12 degrees.
In one embodiment, the angle between adjacent pleats is 10 degrees.
In one embodiment, the angle between adjacent pleats is 8 degrees or
less.
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The number of pleats is inversely related to the angle between adjacent
pleats. Accordingly, it is possible to achieve a low angle between
adjacent pleats by applying more pleats.
Moreover, since the total filter area is proportional to the number of
pleats, it is possible to increase the total filter area by increasing the
number of pleats.
In one embodiment, the irradiation is carried out by using a UV lamp,
wherein the lowest position of the UV lamp is the distal portion of the
UV lamp, wherein an air gap is provided between the bottom plate of
the housing and the distal portion of the UV lamp.
Accordingly, shadow areas (non-irradiated intake air leaving the
housing) can be avoided. Moreover, particles that fall down to the
bottom plate of the housing will be exposed to UV irradiation from the
UV lamp.
In one embodiment, the light irradiation is carried out by using a UV
lamp that extends vertically.
In one embodiment, the method applies a housing that comprises a
bottom portion and a top portion configured to be detachably attached
to the bottom portion.
In one embodiment, the method comprises the step of applying a fan
that is arranged in the top portion, wherein the light irradiation portion
of the UV lamp is arranged in the bottom portion.
In one embodiment, the method is carried out by using inlet
perforations that are provided in the top portion of the housing and
outlet perforations that are provided in the bottom portion of the
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housing.
In one embodiment, the method comprises the step of applying a fan
that has a horizontally orientated intake portion and a vertical output
portion so that air pressurised by the fan leaves the fan in a
downwardly vertical direction.
In one embodiment, the method comprises the step of applying an
additional layer arranged at the outside of the filter.
In one embodiment, the method comprises the step of applying an
additional layer that comprises activated carbon.
In one embodiment, the method comprises the step of applying an
additional layer that is sandwiched between the housing and the filter,
wherein the additional layer comprises activated carbon.
Hereby, the activated carbon can remove unwanted odours by acting as
an adsorbent which will trap the odour inside the activated carbon and
retain it. Moreover, the additional layer can prevent UV light from
escaping to the surroundings.
In one embodiment, the method comprises the step of applying a
coarse filter to filter the intake air before the intake air is sucked into
the fan.
In one embodiment, the method comprises the step of applying a
particle sensor arranged to detect the level of particles in the air.
In one embodiment, the method comprises the step of applying a
particle sensor arranged inside the housing. Hereby, the particle sensor
can detect the level of particles in the intake air entering the housing.
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In one embodiment, the method comprises the step of applying a
particle sensor arranged inside the top portion of the housing. Hereby,
the particle sensor can detect the level of particles in the intake air
entering the top portion of the housing.
In one embodiment, the method comprises the step of applying a
particle sensor arranged inside the bottom portion of the housing.
Hereby, the particle sensor can detect the level of particles in the intake
air entering the bottom portion of the housing.
The method comprises the step of applying a smoke alarm to detect the
smoke content in the air.
The method comprises the step of applying a smoke alarm that is
arranged inside the housing. Hereby, the smoke alarm can detect the
level of smoke in the intake air entering the housing.
In one embodiment, the smoke alarm is arranged inside the top portion
of the housing. Hereby, the smoke alarm can detect the level of smoke
in the intake air entering the top portion of the housing.
The method comprises the step of applying a smoke alarm arranged
inside the bottom portion of the housing. Hereby, the smoke alarm can
detect the level of smoke in the intake air entering the bottom portion
of the housing.
In one embodiment, the method comprises the step of controlling the
speed of the fan in dependence of the detected level of particles in the
air.
In one embodiment, the method comprises the step of applying a
control unit that is configured to control the speed of the fan in
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dependence of measurements made by the smoke alarm.
In one embodiment, the method comprises the step of applying a
control unit that is configured to turn on the fan if the particle content
5 of the intake air exceeds the predefined level.
In one embodiment, the method comprises the step of applying a
control unit that is configured to turn on the UV lamp if the particle
content of the intake air exceeds the predefined level.
In one embodiment, the method comprises the step of applying a
control unit that is configured to turn on the fan and the UV lamp if the
particle content of the intake air exceeds the predefined level.
In one embodiment, the method comprises the step of applying a
control unit that is configured to regulate the speed of the fan in
dependency of the detected level of particle content (detected by the
particle sensor).
In one embodiment, the control unit is configured to adjust the speed of
the fan to take one of two or more predefined non-zero levels.
In one embodiment, the method comprises the step of applying a
control unit that is configured to adjust the speed of the fan to take one
of three or more predefined non-zero levels.
In one embodiment, the method comprises the step of applying a
control unit that is configured to adjust the speed of the fan in an
ungraduated manner on the basis of the detected level of particle
content. This may be done by fitting the fan with a permanent magnet
motor and a frequency converter. This will furthermore allow the
provision of the lowest possible energy consumption.
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In one embodiment, the predefined particle content level is a default
quantity. In another embodiment, however, the predefined particle
content level can be adjusted by using a control unit of the purification
device.
Description of the Drawings
The invention will become more fully understood from the detailed
description given below. The accompanying drawings are given by way
of illustration only, and thus, they are not !imitative of the present
invention. In the accompanying drawings:
Fig. 1 shows a perspective side view of an air
purification device
according to the invention;
Fig. 2 shows a perspective top view of the purification device
shown in Fig. 1;
Fig. 3A shows a schematic top view of a filter according
to the
invention;
Fig. 3B shows a close-up view of the filter shown in
Fig. 3A;
Fig. 3C shows a prior art filter;
Fig. 4 shows a blown up (close-up) cross-sectional view
of a
portion of the inner space surrounded by a filter of a
purification device according to the invention;
Fig. 5 shows a cross-sectional view of the bottom
portion of a
purification device according to the invention;
Fig. 6 shows a flow chart illustrating how the
purification device
according to the invention can be autonomously controlled
by means of a particle sensor;
Fig. 7A shows a graph illustrating the concentration as
function of
time;
Fig. 7B shows a graph illustrating the relative
concentration as
function of time;
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Fig. 8 shows a table with test results and
Fig 9 shows the setup used in the testing.
Detailed description of the invention
Referring now in detail to the drawings for the purpose of illustrating
preferred embodiments of the present invention, an air purification
device 2 of the present invention is illustrated in Fig. 1.
Fig. 1 is a perspective side view of an air purification device 2 according
to the invention. The air purification device 2 comprises a housing 10
having a bottom portion 16 and a top portion 18 configured to be
detachably attached to the bottom portion 16.
The bottom portion 16 is equipped with wheels 24 for improving the
mobility of the air purification device 2.
The top portion 18 is cylindrical and comprises a panel 28 provided on
the top of the top portion 18. In one embodiment, both comprise a
display and one or more buttons.
The top portion 18 comprises a coarse filter 26 separated into four filter
segments that are slidably arranged in filter tracks extending axially
near the rim of the top portion 18. A plurality of air inlet perforation 8
are provided in the cylindrical outer surface of the top portion 18. The
coarse filter 26 is adapted to prevent objects larger than a predefined
size (e.g. 5 og 20 pm) to enter the inner space of the top portion 18.
An electrically driven fan 12 is arranged inside the inner space of the
top portion 18. The fan 12 is an axial fan designed to cause intake air 4
to flow through the fan 12 in an axial direction, parallel to the shaft
about which the blades of the fan 12 rotate. The fan 12 has a
horizontally orientated intake portion and a vertical output portion so
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that air pressurised by the fan 12 leaves the fan 12 in a downwardly
vertical direction.
The bottom portion 16 comprises an inner space 22 defined by an
enclosing cylindrical high-efficiency particulate air (HEPA) filter. An
ultraviolet radiation lamp 14 is centrally arranged in the inner space 22.
In a preferred embodiment, the ultraviolet radiation lamp 14 is a
germicidal lamp (an ultraviolet C lamp). This may be an advantage
since ultraviolet C light (wherein the wavelength in the range of 100 to
280 nm) is capable of destroying and thus inactivating bacteria, viruses,
and protozoa.
The UV C lamp 14 is arranged to irradiate the intake air 4 flowing into
the inner space 22 of the bottom portion 16. Accordingly, the UV C
lamp 14 is capable of disinfecting the intake air 4 flowing into the inner
space 22 of the bottom portion 16.
The purification device is configured to receive intake air 4 through air
inlet perforations 8 and allow the intake air 4 to flow through the filter
20 and leave the bottom portion 16 through air outlet perforations 8'
provided in the housing 10. In the top portion 18, four coarse filter
segments 26 are slidably arranged in filter tracks extending axially near
the rim of the top portion.
Fig. 2 illustrates a perspective top view of the purification device 2
shown in Fig. 1. It can be seen that the purification device 2 comprises
an electrical plug 30 for electrically connecting the purification device 2
to the mains. Hereby, the fan inside the housing 10 of the purification
device 2 can be powered. It can be seen that the top portion is provided
with a plurality of air inlet perforations 8. The bottom portion is
provided with a plurality of air outlet perforations 8'.
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Fig. 3A illustrates a schematic top view of a filter 20 according to the
invention. The filter 20 comprises a plurality of pleats.
Fig. 3B illustrates a close-up view of the filter 20 shown in Fig. 3A,
wherein Fig. 3C illustrates a prior art filter 20'. It can be seen that the
angle a between the air flow direction 42 and the side portion of the
adjacent pleat 32 of the filter 20 shown in Fig. 36 is smaller than the
angle 13 between the air flow direction 42 and the side portion of the
adjacent pleat 32 of the prior filter 20 shown in Fig. 3C. Moreover, it
can be seen that the angle 0 between adjacent pleats 32 of the filter 20
in the purification device 2 according to the invention is smaller than
the angle co between adjacent pleats 32 of the prior art filter 20 shown
in Fig. 3C.
Due to the small acute angle 0, the retention capability of the filter 20 is
increased by having an increased number of pleats 32 compared to the
prior art filter shown in Fig. 3C.
In one embodiment, the angle 0 is 30 degrees or less.
In one embodiment, the angle 0 is 28 degrees or less. In one
embodiment, the angle 0 is 26 degrees or less. In one embodiment, the
angle 0 is 24 degrees or less. In one embodiment, the angle 0 is 22
degrees or less. In one embodiment, the angle 0 is 20 degrees or less.
In one embodiment, the angle 0 is 18 degrees or less. In one
embodiment, the angle 0 is 16 degrees or less. In one embodiment, the
angle 0 is 14 degrees or less. In one embodiment, the angle 0 is 12
degrees or less. In one embodiment, the angle 0 is 10 degrees or less.
In one embodiment, the angle 0 is 8 degrees or less. The number of
pleats 32 is inversely related to the angle 0. Accordingly, it is possible to
achieve a low angle 0 by applying more pleats 32.
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Moreover, the total filter area is proportional to the number of pleats
32. Accordingly, it is possible to increase the total filter area by
increasing the number of pleats 32.
5 Fig. 4 illustrates a blown-up cross-sectional view of a portion of the
inner space surrounded by a filter 20 of a purification device according
to the invention. It can be seen that the filter 20 comprises a through-
going opening 38 configured to retain large sized virus particles inside
the inner space and allow small sized particle to pass through the filter
10 20 through the through-going opening 38.
A large number of virus particles 36 are placed near the entry to the
through-going opening 38. The virus particles 36 are interconnected
and arranged in a cloud-formed formation 34 comprising virus particles
15 36 and airway mucus. Accordingly, the cloud-formed formation 34
cannot escape through the through-going opening 38 even though the
size of the individual virus particles 36 is smaller than the width D of
the through-going opening 38. In fact, the cloud-formed formation 34
comprising virus particles 36 and airway mucus will stick to the inside
20 surface of the filter 20.
The virus particles 36 are irradiated with UV light from a UV lamp
(preferably a UV C) arranged to irradiate the air and particles present in
the inner space. Since the virus particles 36 are trapped inside the
space defined by the inner surface of the filter 20, there is sufficient
time available to destroy the virus particles 36 by the ultraviolet (UV)
light 50.
Fig. 5 illustrates a cross-sectional view of the bottom portion of a
purification device 2 according to the invention. The purification device
2 comprises a housing 10 provided with a plurality of air outlet
perforations 8' for allowing purified air 6 to leave the purification device
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2.
The purification device 2 is configured to blow intake air 4 downwards
into the inner space of the bottom portion of the purification device 2.
Since the intake air 4 enters the purification device 2 in the top portion
of the purification device 2, the intake air 4 will typically not suck
particles from floor level into the purification device 2. The purified air 6
leaves the purification device 2 in a lower level than the level at which
intake air 4 enters the purification device 2.
The purification device 2 comprises a UV light source (preferably a UV C
lamp) 14 configured to irradiate the intake air 4 flowing into the inner
space 22 of the bottom portion of the purification device 2. Hereby, it is
possible to disinfect the intake air inside the inner space 22 of the
bottom portion of the purification device 2.
The purification device 2 comprises a HEPA filter 20 having a large
number of pleats (as explained with reference to Fig. 3B) in order to
achieve a small angle a (e.g. of 15 degrees or less as shown in and
explained with reference to Fig. 3B) and a large total filter area.
The lowest position of the UV lamp 14 is the distal portion of the UV
lamp 14 which is provided at a distance above the bottom plate 44 of
the housing 10. Accordingly, an air gap 44 is provided between the
bottom plate 46 of the housing 10 and the distal portion of the UV lamp
14. Wheels are rotatably attached to the bottom plate 46.
An additional layer 40 may optionally be arranged at the outside of the
filter 20. In one embodiment, the additional layer 40 may be a layer
that comprises activated carbon. Activated carbon can remove
unwanted odours by acting as an adsorbent which will trap the odour
inside the activated carbon and retain it.
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An additional layer 40 may furthermore prevent UV light 50 from
escaping to the surroundings.
In a preferred embodiment, the additional layer 40 is an additional layer
40 sandwiched between the housing 10 and the filter 20, wherein the
additional layer 40 comprises activated carbon.
Fig. 6 is a flow chart illustrating how the purification device according to
the invention can be autonomously controlled by means of a particle
sensor.
Initially the purification device is turned on. In one embodiment, the
particle sensor of the purification device is turned on as default. In one
embodiment, the particle sensor of the purification device is turned on
and cannot be turned off.
The particle sensor of the purification device is configured to measure
the particle content of the intake air. If the particle content of the intake
air exceeds a predefined level, the fan of the purification device is
turned on (or kept turned on if the fan has already been turned on).
If, on the other hand, the particle content of the intake air does not
exceed the predefined level, the fan of the purification device is turned
off (or kept turned off if the fan has already been turned off).
In one embodiment, both the fan and the UV lamp are turned on if the
particle content of the intake air exceeds the predefined level.
In one embodiment, the speed of the fan is selected in dependency of
the detected level of particle content.
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In one embodiment, the speed of the fan can be set to two or more
predefined non-zero levels.
In one embodiment, the speed of the fan can be set to three or more
predefined non-zero levels.
In one embodiment, the speed of the fan can be steplessly adjusted on
the basis of the detected level of particle content. This may be done by
fitting the fan with a permanent magnet motor and a frequency
converter. This will furthermore allow the provision of the lowest
possible energy consumption.
In one embodiment, the predefined particle content level is a default
quantity. In another embodiment, however, the predefined particle
content level can be adjusted by using a control unit of the purification
device.
Fig. 7A and Fig. 7B show graphs that illustrate the results of a study
performed by Danish Technologic Institute using a modified ISO 16000-
36:2018 method with the purpose of determining the efficacy of the
invention (air purification device) to reduce the concentration of active
aerosolized Emesvirus zinderi (MS2) bacteriophages.
Fig. 7A shows a graph illustrating the concentration of active MS2 over
time for the product test and the reference experiment. The y-axis scale
is logarithmic.
It can be observed that after 30 minutes the air purification device is
able to reduce the concentration of active aerosolized MS2
bacteriophages to below the detection limit.
Fig. 7B shows a graph wherein the relative concentration is plotted
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against time. The reduction rates are calculated as described in ISO
16000-36:2018 section 8.3.
It can be observed that the change in relative concentration is nearly
100%.
Epecially, the study concludes that the reduction rate at 15 minutes is
99.98-% and above 99.99-% at 30 minutes.
Fig. 8 shows a table of the results of test to determine the virucidal
activity of the air purifiers UV-C photolysis system.
In the test, virus is captured in the HEPA filter of the device as the
device removes aerosolized MS2 bacteriophages from the air,
whereafter the virus is exposed to the UV-C light inside the device. The
test is designed to examine if virus remains active on the filter following
removal from the air.
Samples are taken prior to and after the air purification has been run
for 30 minutes. The test is performed after the other test shown in Fig.
7A and Fig. 7B.
The samples are analysed according to Danish Technological Institute's
method: MIA-216.
After 30 minutes usage of the air purification device (the invention) the
amount of viral load is reduced to below the detection limit.
Hereby, it can be observed that an efficient purification has occurred for
both the filter and the surrounding air, hereby proving the surprising
efficiency of the solution provided by the invention.
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Hereby, the invention provides an efficient means for air purification of
viral particles, and hereby also provides a device that is safe to perform
maintenance on by personal.
5 Fig. 9 shows the setup used in the testing. The testing was
conducted in
an airtight room having a volume of 20m3. A nebuliser 54 arranged in
the room was used to generate aerosols. A mixing fan 52 was placed in
the room in order to provide air circulation. The purification device 2
was centrally arranged on the floor in the room and the sampling points
10 56 were located on a wall in the room.
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List of reference numerals
2 Purification device
4 Intake air
6 Purified air
8 Air inlet perforation
8' Air outlet perforation
Housing
12 Fan
10 14 Ultraviolet radiation lamp
16 Bottom portion
18 Top portion
Filter
22 Inner space (enclosure)
15 24 Wheel
26 Coarse filters
28 Control panel
Electrical plug
32 Pleat
20 34 Cloud-formed formation
36 Virus particle
38 Through-going opening
Additional layer
42 Air flow direction
25 44 Air gap
46 Bottom plate
Ultraviolet (UV) light
52 Mixing fan
54 Nebuliser
30 56 Sampling ports
a, f3, e, co Angle
D Width
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