DK201670860A8 - Clean room filter unit - Google Patents

Abstract

A ventilation device for ventilating and cleaning air, the device comprising a hollow fan chamber with a fan module, the fan module comprising a fan wheel having a hub on which a plurality of fan blades are arranged, said fan module being arranged at least partly in said fan chamber and being adapted to draw outside air into the fan module when the fan module is in an activated configuration, a filter unit comprising a filter for removing impurities, a separate hollow pressure chamber arranged between said fan chamber and said filter unit so as to guide the air from the fan module to a substantial laminar flow into the filter, the fan chamber and the separate pressure chamber have an opening in between them for air flow passage.

Description

Field

The present invention relates to a low-noise ventilation device for providing filtered air, to a mobile air cleaning unit comprising such a ventilation device and a biological safety cabinet comprising such a ventilation device.

Background

Ventilation devices are widely used in the industry, medical and research facilities, where there is a need for air to be purified from a variety of particles such as smoke particles and gases such as Volatile Organic Compound (VOC)-gasses, ozone, pollen, airborne fungal spores, airborne bacteria and viruses, airborne DNA/DNase, acrolein etc., since these gases and particles can be very harmful to humans if inhaled.

Exposure to various components such as VOCs increases the likelihood of experiencing symptoms of sick building syndrome.

There exist many different ventilation devices for this purpose both for commercial and home use, including biological safety cabinets, fume hoods, air cleaners, built in ceiling cleaning units, flow benches, supply air devices, mobile extractors etc.

These different ventilation devices often have the same basic components in that they all comprise a housing, a fan and a filter. However, these ventilation devices often generate high levels of noise during operation, vibrate excessively and use a lot of energy. The high noise levels may disturb the nearby personnel, which often perform precise and delicate works tasks right below such a ventilation device. They therefore provide poor work environment.

To overcome the noise problem different noise minimizing features have been suggested. US 5,961,702 disclose such a ventilation device, which uses an acoustic damping lining on the inside of the housing and a hood muffler around the fan as noise minimizing features.

It may, however be cumbersome to secure both the damping lining to the inside of the housing and the hood muffler to the fan, rendering this type of ventilation device expensive to manufacture and service. Further with the plurality of different components disposal of the ventilation device also becomes more burdensome.

Thus it remains a problem to provide a ventilation device that is easy and cheap to manufacture, and easy to service and dispose of.

Summary

According to a first aspect, the invention relates to a ventilation device (1) for ventilating and cleaning air, the device comprising; - a hollow fan chamber with a fan module, the fan module comprising a fan wheel having a hub on which a plurality of fan blades are arranged, said fan module being arranged at least partly in said fan chamber and being adapted to draw outside air into the fan module when the fan module is in an activated configuration, - a filter unit comprising a filter for removing impurities, and - a separate hollow pressure chamber arranged between said fan chamber and said filter unit so as to guide the air from the fan module to a substantial laminar flow into the filter, the fan chamber and the separate pressure chamber have an opening in between them for air flow passage.

Consequently, by using a combination of a fan chamber and a separate hollow pressure chamber, the ventilation device is made of few parts, which are easy to assemble whilst still providing noise reduction. The fan chamber and the separate pressure chamber are constructed in such a way, that airflows in the same direction with very little turbulence. As the airflows in the same direction the noise, vibration and energy consumption is significantly reduced which has a positive influence on the working environment.

The wording “activated configuration” is in the content of this specification referring to the configuration where a motor, which is arranged in connection with the fan module is activated. The motor provides rotational movement of the fan wheel, so that the fan module draws air externally from the inlet and discharges it via the circumference of the fan hub, guided by the fan blades.

The air to be cleaned is also in the content of this description referred to as outside air, meaning the air surrounding the invention, which air is to be sucked into and through the invention.

The wording “separate hollow pressure chamber” is to be understood as a chamber that is formed or viewed as a unit apart or by itself, not forming part of the fan chamber. The pressure chamber comprises at least a side wall, a top wall and a bottom wall defining an internal spacing.

The separate hollow pressure chamber may have different shapes such as rectangular, square or cylindrical.

In the content of this specification the term “hollow” is to be interpreted as the chamber comprising an internal spacing inside, said spacing being an empty space without any elements present.

The hollow fan chamber is in itself a hollow chamber that further comprises the fan module.

Laminar flow is in fluid dynamics and in this specification to be understood as the air flowing in parallel layers with no disruption between the layers. There is no cross-current perpendicular to the direction of air flow.

Air from the fan chamber enters the pressure chamber, wherein the air is guided into the filter, the air flow entering the filter having a substantially laminar flow.

The shape of the fan chamber surrounding the fan module guides the air down towards the pressure chamber and the filter.

The filter may be a HEPA-filter, active carbon filter, TiOc filter, ozone filter, ULPA-filter, a combination of these. The filter may also be another type of air cleaning filter know to a person skilled in the art.

When it comes to ventilation devices like the present invention, it is important to be able to maintain an (approximately constant) uniform, laminar air velocity at the filter outlet side. In the existing solutions on the market, wherein only the housing is present (no pressure chamber), more turbulence will be present. The turbulence will have a negative effect on the air velocity and it will be necessary to speed up the fan. Additionally, the turbulence will ensure that it is not possible to achieve a uniform air velocity across the entire filter unit.

Other solutions on the marked attempt to overcome this problem by arranging various panels into the fan chamber in order to distribute the air better, but because of the larger surface area that the air must pass a pressure loss will occur, forcing the speed of the fan to be adjusted to a higher speed level. This is energy wise very expensive. If for example the fan speed is doubled then the energy consumption will be quadrupled - i.e. if the fan uses 100 watts at an air speed of 0.3 m/sec through the filter unit, the fan will use 400 watts at an air speed of 0.6m/sec through the filter unit.

When providing the filter unit according to the invention, the energy consumption is significantly reduced along with the turbulence and thus the noise level.

The fan may be a conventional radial fan.

The filter unit and the pressure chamber may be arranged substantially parallel to each other.

The filter unit inlet wall and/or the filter unit outlet side may be arranged substantially parallel with the pressure chamber upper wall and/or lower side.

The filter unit and/or the pressure chamber may be arranged substantially parallel to the filter unit.

The fan module defines a radial direction.

The filter unit and/or the pressure chamber may be arranged substantially parallel to the radial direction of the fan module. A substantial amount of the air expelled from the fan module may only encounter on its way to the pressure chamber the fan chamber side wall.

Some of the air expelled from the fan module may enter directly into the pressure chamber.

It is noted that the air flow in the pressure chamber is approximately linear and free of reversal of flow direction within the pressure chamber.

When the air flow from the fan chamber enters the pressure chamber and thereafter encounters lower flow rates through the filter unit, an increased air pressure is established within the pressure chamber.

This ensures that the air is directed from the fan module and into the pressure chamber.

In some embodiments the hollow fan chamber having an air inlet formed on an inlet wall thereof and an air outlet formed on an outlet side opposite to said inlet wall, wherein a side wall is provided between the inlet and outlet sides, the separate hollow pressure chamber comprises a chamber upper wall having a perforation and abutting the outlet side of the fan chamber, an opposite chamber lower side, side walls provided between the chamber upper and lower sides, the upper and lower sides and the side walls defining an internal spacing, and the filter unit comprises a filter inlet wall, an opposite filter outlet side and the filter is arranged between said inlet and outlet side, where the filter inlet wall abuts the chamber lower side, so that when the fan module is in the activated configuration, outside air is drawn into the fan module through said inlet and guided by said fan chamber through the internal spacing of the pressure chamber and out through the filter unit.

Consequently, since the air flow is guided from the fan chamber through the pressure chamber and subsequently through the filter unit, the air being guided in the same direction, the amount of air turbulence will be significantly reduced and as a result thereof the vibrations, noise and energy consumptions is also reduced. This has a positive effect on the surrounding work environment, providing a more pleasant ambient noise level.

Since the ventilation device comprises three different parts; the fan chamber (with the fan module), the pressure chamber and the filter unit, the ventilation device is easy to assemble and cheap to manufacture.

Also, since the different parts can be easily separated from each other the ventilation device is easy to service.

If a part of the ventilation device malfunctions or breaks down, there is no need to replace the entire device, since the specific parts (e.g. the fan chamber, the pressure chamber or the filter unit) easily can be replaced instead, thereby avoiding a costly replacement of the entire device.

The perforation may have any shape such as the shape of a triangle, circle, rhombus, trapezoid, square or semicircle.

The internal spacing of the pressure chamber ensures that the air will be distributed across the entire filter inlet wall. Consequently, the amount of air turbulence is reduced, since the air can flow without any obstructions that would cause the air to bounce back in a different direction creating turbulence. The reduced amount of turbulence ensures that the amount of vibrations and accordingly noise is reduced.

The air exits the filter unit on the filter outlet side. The air preferably has a uniform air velocity. Additionally or alternatively the air preferably has a laminar air velocity. The air velocity is approximately 0.1-0.5 m/sec, preferably 0.2-0.4 m/sec, more preferred 0.3 m/sec.

The width of the fan chamber may be less than the width of the pressure chamber. Each width being measured from side wall to side wall.

The length of the fan chamber may be less than the length of the pressure chamber. Each length being measured from side wall to side wall.

The width of the pressure chamber is 5 -30 % larger than the width of the fan chamber, preferably 5 - 20 %, more preferred 10-15 %.

The pressure chamber upper wall extends beyond and away from the side wall of the fan chamber.

The upper wall may extend at an angle of approximately 90 degrees.

The at least one side wall of the pressure chamber may extend from the upper wall of the pressure chamber at an angle of approximately 90 degrees.

The pressure chamber upper wall is attached to the side walls of the pressure chamber.

The height of the pressure chamber is approximately 45 - 55 % of the height of the fan chamber, preferably approximately 40 - 60 %, more preferred approximately 35 - 65 %.

The radial direction of the fan may be parallel to the pressure chamber upper wall.

The radial direction of the fan may be parallel to the filter inlet wall.

The inlet wall may be substantially flat.

The chamber upper wall of the pressure chamber may be substantially flat.

The pressure chamber upper wall may separate the pressure chamber and the fan chamber.

The pressure chamber is preferably generally rectangular.

In some embodiments the separate hollow pressure chamber allows unobstructed airflow in the internal spacing.

Consequently, the internal spacing allows the airflow to be guided in the same direction thus reducing turbulence and associated noise.

In the content of this specification the term “allows unobstructed airflow” is to be interpreted as the hollow pressure chamber having no obstructions present that will alter the direction of the air flow, not including the pressure chamber itself.

Since the separate hollow pressure chamber is constructed of few parts, it is cheap and easy to produce which renders the entire device more cost-effective.

The fan hollow fan chamber may allow unobstructed airflow of the air from the fan module in said hollow fan chamber.

This ensures that part of the air expelled from the fan module enters directly into the pressure chamber from the fan chamber. A substantial part of the air expelled from the fan chamber may have its flow direction altered by the side wall of said fan chamber, the said wall being the only element that alters the direction of said air in said fan chamber.

The hollow fan chamber comprises an internal fan space. The fan space is defined by the inlet wall, the outlet side and the side wall. The fan module is arranged inside the hollow fan chamber in the fan space.

The fan module may be arranged at least partly in said fan chamber.

The fan module may be arranged solely in said fan chamber.

The fan chamber comprises only the fan module in said fan space.

In some embodiments the fan module is adapted so as to discharge air substantially in the entire circumference of the fan wheel.

The air enters the fan wheel from the side of the fan wheel that is arranged adjacent to the fan chamber inlet. The air is turned 90 degrees and accelerates due to centrifugal force as it flows over the fan blades and exits the fan wheel.

The fan blades on the hub may be arranged in a plurality of different ways, such as; forward-curved, backward-curved or radial.

The air that exits the fan wheel may be guided towards the side wall of the fan chamber and/or the pressure chamber.

Some of the air flow may be guided by the side wall of the fan chamber towards the pressure chamber.

With regular centrifugal fans known to the person skilled in the art, the fan wheel is closely covered by a housing with only a small opening, directing the air in a specific direction. This means that all of the air expelled from the fan wheel, that is not expelled directed adjacent to the opening, has to travel around inside the housing to reach the opening and exit the housing. This creates high amounts of turbulence and noise.

By allowing the air flow to exit in the entire circumference of the fan wheel, less turbulence is created compared to traditional centrifugal fans, since the air can freely exit the fan wheel and travel directly into the pressure chamber.

In the context of this specification the wording “entire circumference” is meant as the outer boundary/perimeter of the fan wheel, the air exiting in the radial direction of the wheel guided by fan blades present in the circumference of the fan wheel.

In some embodiments the side wall has a substantially circular circumference.

The side wall may be tapering towards said inlet wall and/or being curved.

Consequently, the air that is expelled from the fan wheel towards the side wall will be guided by the rounding of the side wall in the direction towards the pressure chamber, thus providing a more uniform direction of the air entering the pressure chamber and thus reducing turbulence.

The side wall may be curved across substantially its entire length.

In some embodiments the inlet wall further comprises a flange extending from said inlet wall into said fan module for guiding outside air into the center of said fan module.

In some embodiments the fan wheel is arranged so as to rotate around at least a part of said flange.

By providing the fan module within the fan chamber, the entire ventilation device is small in size and easy to install, since no fan element protrudes outside the fan chamber.

Further, the flange ensures that the outside air is directed into the center of the fan wheel. Thereby, it is avoided that outside air enters the fan chamber between the fan chamber and the fan module which would create unwanted turbulence and noise.

In some embodiments said fan module is arranged adjacent to said perforation so as to partly cover said perforation.

Consequently, the air from the fan module will be able to enter into the pressure chamber substantially directly from the fan chamber.

The air that is expelled from the air wheel will be guided only by the fan camber side wall.

The air will be guided in a direction towards the pressure chamber, and will be directed thereto without any substantial obstructions.

The direct entry of the air from the fan chamber into the pressure chamber ensures less vibration of the ventilation device, since less air will interact with obstacles of the ventilation device. Thus less noise is created and a minimal amount of energy loss will occur.

In some embodiments the outlet side of the fan chamber having a circular shape abuts the chamber upper wall so as to partly cover the perforation.

In some embodiments the fan chamber entirely covers the perforations.

Thereby the fan chamber encloses the perforations on the upper wall of the pressure chamber.

On the outside of the fan chamber a negative pressure will be created, when the fan is in the activated configuration and air is sucked into the fan module. Towards the pressure chamber and the filter unit a positive pressure will be created. This ensures that only air from the fan module enters the pressure chamber and subsequently the filter unit.

In some embodiments the chamber upper wall comprises at least two perforations arranged adjacent to said fan module, said perforations being separated by at least two elongated spacers extending radially from a central wall part.

The central wall part and/or spacers may be used for attachment of the fan module to the pressure chamber.

The central wall part and/or spacers may be used for attachment of the fan chamber to the pressure chamber.

The fan module and/or fan chamber may be attached by any type of attaching means such as nails, screws, welding, adhesives and the like.

Thus the spacers and/or the central wall part provides for easy and simple attachment of the fan chamber and/or the fan module, without the need for a large amount of additional elements.

The only element(s) that the air expelled from the fan module can encounter on its way to the pressure chamber is; the fan chamber side wall and/or the spacers and/or the central wall part.

Some of the air expelled from the fan module may enter directly into the pressure chamber.

In some embodiments the fan module is attached to said central wall part.

The fan module may be rotationally attached to said central wall part.

The fan module may additionally or alternatively be attached to the inlet surface.

Consequently, the fan module can freely rotate with relation to the pressure chamber.

The fan module does not extend into said pressure chamber.

Alternatively or additionally the chamber upper wall of said pressure chamber is substantially flat or plane.

The fan module may be attached only to the central wall part.

In some embodiments the pressure chamber side walls are substan- tially parallel with each other.

Thus the air in the pressure chamber is guided down towards the filter unit without unnecessary turbulence.

The chamber side walls may be tapered towards the filter unit.

The chamber side walls may be curved towards the filter unit.

The chamber side walls may be an elongation of the side wall of the fan chamber.

The height of the pressure chamber side wall is greater than 1 cm, preferably 2-5 cm, more preferred approximately 3 cm.

In some embodiments the device comprises at least two fan chambers and at least two fan modules.

In some embodiments the device comprises one pressure chamber.

By having two fan chambers, each having an appertaining fan module, connected to a pressure chamber, easy installation of more than one fan module is facilitated.

Since the air from each fan module and/or fan chamber is directed down towards the pressure chamber and filter unit, the air from each of the fan modules and/or fan chambers will avoid interference with each other thus not affecting each other’s air flow, thus resulting in reduced energy consumption.

In some embodiments the ventilation device comprises a plurality of fan chambers and a plurality of fan modules.

In some embodiments the ventilation device comprises at least one pressure chamber.

In an embodiment the ventilation device comprises three fan chambers, three fan modules, one pressure chamber and one filter unit.

This provides for a ventilation device that is both space-saving, energy-saving and easy to install.

The length of the entire pressure chamber spans from side wall to side wall across all fan chambers.

The length of the entire pressure chamber is approximately 4-9 times larger than the width of a single fan chamber, preferably 5-8 times, more preferred 6-7 times.

In some embodiments the filter unit further comprises a pre-filter arranged between the filter and the pressure chamber.

The pre-filter may be a HEPA-filter, active carbon filter, TiOc filter, ozone filter, ULPA-filter, a combination of these. The pre-filter may also be another type of air cleaning filter know to a person skilled in the art.

In some embodiments the ventilation device comprises a plurality of filters.

In some embodiments the ventilation device further comprises UV-A lamps, UV-B lamps, UV-C lamps or a combination thereof.

The invention also relates to an air cleaner comprising the ventilation device according to the first aspect of the invention.

The air cleaner may be a mobile air cleaner in the form of a standalone unit. The unit being a mobile unit so as to allow movement from one position to another.

By having a mobile air cleaner it is possible to easily move the air cleaner from and to different desired locations where it is desired to remove contaminants from the air in a room.

These contaminants might also be; dust, pollen, pet dander, mold spores or dust mite feces, which can act as allergens, triggering allergies in sensitive people.

Further a mobile air cleaner can be used where there is no need/room for a permanent ventilation system. It is possible to replace and/or add filters to the same air cleaner, thereby allowing the air cleaner to be utilized in different environments with different pollution.

For example the air cleaner could at one point be used in a laboratory where a HEPA filter and/or a TiOc filter would be arranged in the air cleaner to remove particles, viruses, DNA and so on. The same air cleaner could then at a later stage be used to clean the air in a copy room, where s ozone filter and/or an activated carbon filter would be arranged in the air cleaner to remove ozone and odor.

The construction of the ventilation device according to the invention ar- ranged inside the air cleaner ensures that the noise level of the air cleaner is minimal, thus allowing people to work in the vicinity of the air cleaner without unwanted disturbance.

The invention also relates to a biological safety cabinet comprising the ventilation device according to the first aspect of the invention.

Such a Biological Safety Cabinet (BSC) may be affixed to an air handler unit (AHU) or to an HVAC unit found in the medical, industrial, and commercial industries.

By implementing the ventilation device according to the first aspect into a Biological Safety Cabinet the advantages of the ventilation device such as low sound levels, low vibration, low energy consumption and uniform air flow through the filters are achieved for the BSC. BSCs are often workstations, and if you are situated at such a cabinet for an entire workday, it is of uttermost importance that the noise level is as low as possible, to ensure a comfortable work environment.

Further, low levels of vibrations are also achieved. High amounts of vibrations in a BSC can both be harmful to the psychological health of the person working with the BSC.

In addition, it is advantageous when working with microscopes or laboratory scales inside the BSC that there is as little vibration as possible. The low amounts of vibrations in the ventilation device and thus the BSC according to the invention can result in a stable work setting, where there is no need for a special vibration damping table. BSCs are often activated 24/7, which means that the energy con-consumption is an important aspect. This will be significantly reduced with the ventilation device according to the invention installed in a BSC.

Additionally, it is of uttermost importance that the air flow inside the BSC is void of turbulence and as uniform as possible. If turbulence is present there is a risk, that the subject which is being worked on at one section inside the BSC such as bacteria will be spread around the cabinet and possibly to other subjects inside the BSC, so that cross contamination occurs.

The ventilation device of this invention may be used in many applica- tions including clean air modules, clean air workstations, clean rooms, sterile ceiling system, modular clean air units or soft wall air units.

Brief description of the drawings

The above and/or additional objects, features and advantages of the present invention will be further outlined by the following illustrative and nonlimiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:

Figure 1 shows a cross section of a ventilation device according to an embodiment of the present invention.

Figures 2a-2d shows different perspectives of a fan chamber.

Figures 3a-3d shows different perspectives of a pressure chamber.

Figure 4 shows an exploded view of a ventilation device according to an embodiment of the present invention.

Figure 5 shows a perspective view of the ventilation device shown in figure 4 in an assembled configuration.

Figure 6 shows a cross section of the assembled ventilation device shown in Figure 5.

Figure 7a shows a perspective view of an air cleaner comprising the ventilation device according to an embodiment of the present invention.

Figure 7b shows a cross section of the air cleaner shown in figure 7a.

Figure 8a shows a front view of a biological safety cabinet comprising the ventilation device according to an embodiment of the present invention.

Figure 8b shows a rear view of the biological safety shown in figure 8a

Detailed description

In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

Fig. 1 show a cross-sectional side view of a ventilation device according to an embodiment of the invention in an assembled configuration.

The ventilation device comprises a hollow fan chamber 2. The fan chamber is also shown in various perspectives in figures 2a-2d.

The height of the fan chamber 2 as seen on figure 2a is approximately 50 - 200 mm, preferably 75- 125 mm, more preferred approximately 105 mm.

The fan chamber 2 has an air inlet 23 formed on an inlet wall 21 thereof and an air outlet 25 formed on an outlet side 24 opposite to said inlet wall. A side wall 26 is provided between the inlet and outlet sides.

The inlet wall 21 comprises an inlet surface 29. The inlet wall 21 extends radially from the air inlet 23 to the side wall 26. The inlet surface extends radially from the air inlet 23 to the side wall 26.

The inlet 23 and the outlet 25 defines a through hole 27, having a through hole axis T.

As seen on figure 2c, the air inlet 23 has a circular shape for ensuring equal amounts of air can enter from the entire circumference. The air inlet has a diameter of approximately 100 - 200 mm, preferably approximately 125 - 175 mm, more preferred approximately 155 mm.

The air inlet may have another suitable shape that allows air to flow uniformly from all sides.

The fan chamber 2 has a cylindrical shape. The side wall 26 has a substantially circular circumference. The side wall 26 tapering from said outlet side 24 towards said inlet wall 21 to function as a guiding surface for guiding air towards the outlet side 24.

The side wall 26 extends at an angle from said inlet surface 29. This angle is approximately 75 - 175 °, preferably 90 - 150°, more preferred approximately 125°. A part of the side wall 26 that is connected to the inlet surface 29, may be substantially linear. This part is preferably less than 50 % of the height of the fan chamber 25.

The fan chamber 25 can also be described as having an approximately semi-spherical shape as seen on figure 2d.

The fan chamber 25 may have an approximately spherical shape. The fan chamber 25 may have an approximately cone shape.

This shape with an angled side wall ensures that the air flow from the fan module are directed down towards the pressure chamber without creating unwanted turbulence and consequently unwanted vibrations and pressure loss.

As seen on figure 2c, the air outlet 25 has a circular shape. The air outlet 25 has a diameter of approximately 250 - 450 mm, preferably approximately 300 - 400 mm, more preferred approximately 350 mm.

The diameter of the air outlet 25 is greater than the diameter of the air inlet 23.

The inlet wall 21 further comprises a flange 22. The flange 22 extends from said inlet wall 21, starting at the circumference of the air inlet 23 and the inlet wall 21 into said fan chamber 2.

The flange comprises a first flange part 22a and a second flange part 22b. The first flange part 22a is at one end connected to the inlet wall and at an opposite end connected to the second flange part 22b. The second flange part 22b is at one end connected to the first flange part 22a. The second flange part 22b may comprise an opposite free end.

The first flange part extends at an angle to the inlet surface 29. This angle is approximately 75 - 175 °, preferably 90 - 150°, more preferred approximately 120°. The second flange part 22b extends at an angle to the first flange part.

The flange has a cross section height as seen on figure 2b of approximately 10-30 mm, preferably approximately 15-25 mm, more preferred approximately 19 mm.

The second flange part 22b has a length of approximately 1-15 mm, preferably approximately 4-10 mm, more preferred approximately 6 mm.

The fan chamber 2 may be made of any suitable material such as plastics, aluminium, stainless steel, fiberglass, carbon fiber, steel with a coating such as aluminium-zinc, thermoplastics, mild steel or wood. The fan chamber is preferably made of polylactic acid or polylactide (PLA) plastic.

The outlet side 24 may comprise an outlet surface, wherein the outlet 25 is defined. The outlet side and/or outlet surface may be used as attachment surfaces for attaching other parts of the ventilation device.

The hollow fan chamber 2 further comprises an internal fan space 28. The fan space 28 is defined by the inlet wall 21, the outlet side 24 and the side wall 26. A fan module 3 is arranged inside the hollow fan chamber 2 in the fan space 28.

The fan module 3 may be arranged at least partly in said fan chamber 2.

The fan module 3 comprises a fan wheel 31 having a hub 32 on which a plurality of fan blades 33 are arranged. The fan module 3 is adapted for drawing outside air into the fan module 3, when the fan module 3 is in an activated configuration.

The direction of the outside air drawn into the ventilation device when in its activated configuration is indicated by arrows on figure 1.

The fan module 3 may be a fan module of a commonly known centrifugal fan know to a person skilled in the art.

The fan wheel 31 is adapted for rotating around the through hole axis T.

The activated configuration is in the content of this specification defined as wherein a power source 35, such as a motor, provides electricity for rotating the fan wheel, so that outside air is drawn from outside the fan chamber 2 and into the fan module 3.

The power source may be an internal power source arranged inside the ventilation device or may be located outside the ventilation device.

On figure 1 the power source 35 is arranged between the fan wheel 31 and the pressure chamber 4.

The power source 35 may be attached to the pressure chamber 4. The power source may function as attachment point for the fan wheel 31.

The fan module may also be in an un-activated configuration, where the fan wheel is at a still stand, since no electricity is provided.

The fan wheel 31 may be made from plastic and/or metal such as al- uminium.

The fan wheel 31 comprises an air opening 34 adjacent to said inlet wall 21 of the fan chamber 2.

The flange 22 extends into said fan module 3. More specifically into said air opening. The flange 22 is adapted for guiding outside air into the center of said fan module 3.

The flange 22 may be an integral part of the fan chamber 2. The flange 22 may be molded or cast as a part of the fan chamber.

The flange 22 extends towards the fan wheel 31 in the entire circumference of the air inlet 23. The flange may extend partly in the circumference of the air inlet 23.

The fan wheel 31 is arranged so as to rotate around at least a part of said flange 22. In figure 1 the fan wheel is shown as being arranged to rotate around the second flange part 22b.

The fan module 3 is adapted so as to discharge air in the entire circumference of the fan wheel 31.

As shown on figure 1 the ventilation device further comprises a filter unit 6 comprising a filter 63 for removing impurities or other unwanted particles.

As shown on figure 1 the ventilation device 1 further comprises a separate hollow pressure chamber 4. The pressure chamber 4 according to an embodiment of the invention is shown in different perspectives on figures 3a - 3d.

Figure 3a shows a cross sectional view of the pressure chamber 4. Figure 3b shows another cross sectional view of the pressure chamber 4. Figure 3c shows a top view of the pressure chamber 4. Figure 3d shows a perspective view of the pressure chamber 4.

As seen on figure 1 when the ventilation device 1 is in the assembled configuration, the pressure chamber 4 is arranged between said fan chamber 2 and said filter unit 6. The pressure chamber 4 guides the air from the fan module to a substantial laminar flow into the filter.

The fan chamber 2 and the separate pressure chamber 6 have an opening 25, 45 in between them for airflow passage.

This opening may be formed by the outlet 35 of the fan chamber 2 and the perforation 45 on the pressure chamber 4.

In the context of this specification the term “opening” is to be interpreted as meaning a through-hole extending through both chambers. The opening may be formed by two openings, one in each chamber, the openings being adjacent and abutting each other, so that air can flow unobstructed from one chamber to the other through said opening 25, 45.

The separate hollow pressure chamber 4 comprises a chamber upper wall 41 having a perforation 45. The chamber upper wall 41 abuts the outlet side 24 of the fan chamber 2. The pressure chamber 4 also comprises an chamber lower side 43, opposite the chamber upper wall 41, and side walls 49a - 49d provided between the chamber upper and lower sides. The upper and lower sides 41, 43 and the side walls 49a-d defines an internal spacing 48.

The side walls 49a-d preferably extends perpendicular from the chamber upper wall 41.

The pressure chamber side walls 49a - 49d are substantially parallel with each of the opposite side wall, respectively.

The chamber lower side 43 comprises four first attachment flanges 43a - 43d that extends perpendicularly from the side walls radially away from each other. The first attachment flanges 43a - 43d are arranged so as to serve as attachment points for the filter unit 6 and/or a pre-filter 5.

Each of the first attachment flanges 43a - 43d comprises an additional second attachment flange 43aa - 43dd. Each second attachment flange 43aa - 43dd extend approximately perpendicular from each said first attachment flange.

The second attachment flanges may abut part of the filter unit and/or pre-filter.

The pressure chamber 4 may comprise a plurality of openings 45.

The pressure chamber 4 preferably comprises 6 openings per appertaining fan chamber.

The fan module 3 is arranged adjacent to said perforation 45 so as to partly cover said perforation 45.

The outlet side 24 of the fan chamber 2 has a circular shape and abuts the chamber upper wall 41 so as to cover the perforation 45. The circular shape of the fan chamber 2 encloses the perforation 45, so that air from the fan module in said fan chamber is only able to enter the pressure chamber though said opening.

The chamber upper wall 41 comprises at least two perforations 45a -f arranged adjacent to said fan module 3. The perforations are separated by at least two elongated spacers 46a - 46f extending radially from a central wall part 47.

In the embodiment shown in figures 3a-3d the perforations 45a - 45f are shown in 3 clusters (C1, C2, C3), each cluster appertaining to and intended to be covered by each own fan chamber.

It is to be understood that that embodiment shown in figure 1 comprises one cluster with perforations 45a - 45f like one of the clusters shown and described in the following in relation to figure 3c.

The pressure chamber comprises 6 perforations 45a - 45f. The 6 perforations are preferably arranged in a cluster (C1) having a circular shape. Between each perforation and the adjacent perforation is arranged an elongated spacer. A cluster with 6 perforations 45a - 45f also comprises 6 spacers 46a - 46f.

The number of spacers is preferably equal to the number of perforations.

Each cluster of perforations 45a - 45f also comprises a central wall part 47. Each spacer extends radially from said central wall part 47.

The spacers 46a - 46f and the central wall part 47 may form part of the chamber upper wall 41.

The central wall part 47 is preferably circular. The central wall part 47 is arranged adjacent to and abutting the fan module 3. The central wall part may function as an attachment surface for the fan module 3.

The fan module 3 is rotationally attached to said central wall part 47. A perforation 45a - 45f preferably has a trapezoid shape, but may have any other shape such as triangular, rectangular, circular and/or square, as long as it allows air flow into said pressure chamber.

The pressure chamber shown in figures 3a - 3d comprises three clusters (C1-3) of perforations 45a - 45f. Each cluster comprises 6 perforations 45a - 45f, 6 spacers 46a - 46f and a central wall part 47.

The pressure chamber preferably has an elongated, rectangular shape. The pressure chamber 4 may have any suitable shape such as square, circular and the like.

The chamber upper wall 41 and/or the central wall part 47 and/or the spacers 46a - 46f may serve as attachment point for the fan module 3 and/or the fan chamber 2.

The pressure chamber 4 may be made of any suitable material such as thermoplastics, stainless steel, fiberglass, carbon fiber, steel with a coating such as aluminium-zinc, mild steel or wood.

The pressure chamber 4 is preferably made of aluminium. The pressure chamber has a wall thickness of approximately 1-5 mm, preferably approximately 1 - 3 mm, more preferred approximately 2 mm.

In the embodiment shown in figure 1 the ventilation device comprises 6 perforations 45a - 45f, 6 spacers 46a - 46f and one central wall part 47 (these are not visible from figure 1).

The pressure chamber 4 of figure 1 has a total height of approximately 40 mm - 120 mm, preferably 50 mm - 90 mm, more preferred approximately 63 mm.

The pressure chamber 4 has a total width of 400 mm - 650 mm, preferably 450 mm - 550 mm, more preferred approximately 490 mm.

The pressure chamber 4 shown in figures 3a - 3f has a height of approximately 40 mm - 120 mm, preferably 50 mm - 90 mm, more preferred approximately 63 mm.

The pressure chamber 4 a total length of approximately 900 mm -1500 mm, preferably 1000 mm - 1250 mm, more preferred approximately 1106 mm.

The radius of a circular central wall part 47 is approximately 30 - 70 mm, preferably approximately 40 - 60 mm, more preferred approximately 50 mm.

The radius of a circular cluster is approximately 150-190 mm, preferably approximately 160-180 mm, more preferred approximately 170 mm.

The ventilation device 1 further comprises a filter unit 6. The filter unit comprises a filter inlet wall 61 and an opposite filter outlet side 62. The filter unit 6 further comprises a filter 63 arranged between said inlet and outlet side.

The filter unit 6 may be arranged so that the filter inlet wall 61 abuts the chamber lower side 43.

The filter unit 6 further comprises a pre-filter 5. The pre-filter is arranged between the filter 63 and the pressure chamber 4.

The filter unit 6 and/or pre-filter 5 are preferably rectangular so as to match the shape of the pressure chamber.

The filter unit 6 and/or pre-filter 5 may have any shape such as square or circular, as long as it matches the shape of the pressure chamber.

The above described arrangement of the fan module 3, the pressure chamber 4 and the filter unit 6 ensured, that when the fan module 3 is in the activated configuration, outside air is drawn into the fan module 3 through said inlet 23 and is guided by said fan chamber 2 through the internal spacing 48 of the pressure chamber 4 and out through the filter unit 6.

The separate hollow pressure chamber 4 allows unobstructed airflow in the internal spacing 48. This ensures less turbulence and a more uniform laminar airflow into and through said filter unit.

The filter unit 6 may be formed so as to allow the pre-filter to be arranged within said filter unit 6, the sides of the pre-filter abutting the side walls of said filter unit.

In an assembled embodiment of the ventilation device 1 as shown on figure 5, the ventilation device comprises three fan chambers 2a - 2c and three fan modules 3a - 3c. The ventilation device 1 further comprises one pressure chamber 4, whereto the fan chambers and fan modules are attached. The ventilation device 1 also comprises a pre-filter 5 (shown on figure 6), arranged adjacent to the pressure chamber 4, and a filter unit 6 (shown on figure 6), which is arranged adjacent to the pre-filter 5.

Figure 6 shows a cross-sectional view of the ventilation device in figure 5.

The pre-filter 5 is arranged between the filter unit 6 and the pressure chamber. 4.

Figure 7a shows a perspective view of an air cleaner 7 comprising the ventilation device 1. Figure 7b shows a cross section of the air cleaner 7 shown in figure 7a.

The air cleaner 7 comprises an outer casing 71. The casing 71 comprises an inlet 72 and an outlet 73 arranged opposite said inlet 72. When in an activated configuration outside air will enter the air cleaner through said inlet 71 and exit the air cleaner through said outlet 73.

The inlet 72 comprises a pre-filter 5, which is arranged in said inlet 72. When outside air is sucked into the air cleaner 1, the air initially passes through the pre-filter 5 before entering the air cleaner 7.

The air cleaner 7 further comprises a hollow fan chamber 2 and fan module 3 as described in relation to figure 1.

When in an activated configuration the fan wheel 31 draws outside air into the fan chamber 2 through the pre-filter 5, the fan chamber air inlet 23 and the fan wheel 31 itself.

The air cleaner further comprises a pressure chamber 4, which is arranged adjacent to the fan chamber 2 and the fan module 3. The air from the fan chamber 2 is then directed into the pressure chamber 4.

The outlet side of the fan chamber 2 is attached to the chamber upper wall 41 of the pressure chamber 4.

The fan module 3 is attached to the chamber upper wall 41 of the pressure chamber 4.

The air cleaner 7 further comprises a filter unit 6. The filter unit 6 is arranged adjacent to a chamber lower side 43 of said pressure chamber 4, so that air passing through said pressure chamber 4, will be directed into and through said filter unit 6.

The filter unit comprises a filter 63. The filter 63 may be a carbon filter.

The air cleaner 7 further comprises a sterilization unit 9. The sterilization unit 9 is arranged adjacent to the filter unit, so that the air that passes through the filter unit 6 is directed into and through the sterilization unit 9.

The sterilization unit 9 comprises an UV light source 91 and a light casing 92. The casing 92 surrounds the light source 91, so that the light does not exit the casing 92.

The sterilization unit 9 further comprises a guide 93 that guides the light from the light source 92 in a desired direction.

On the other side of the sterilization unit 9, i.e. opposite the filter unit 6 is arranged a second filter unit 6a, so that the air that passes through the sterilization unit 9 is directed into and through the second filter unit 6a.

The second filter unit 6a comprises a filter 63a. The filter 63a may be a T1O2 filter.

On the other size of the second filter unit 6a, opposite the sterilizations unit 9, a third filter unit 6b is arranged, so that the air that passes through the second filter unit 6a is directed into and through the third filter unit 6b.

The third filter unit 6b comprises a filter 63b. The filter 63b may be a HEPA filter.

The air cleaner 7 further comprises a power source 35 and an appertaining controller (not shown) for controlling the air cleaner 7, e.g. shifting from an un-activated configuration to an activated configuration and vice versa or changing the speed of the fan wheel 31.

The route through the air cleaner 7 for outside air to be cleaned is thus; - in through the pre-filter 5 in the inlet 72 of the casing 71, - through the inlet 23 of the fan chamber 2, - through the fan wheel 31 if the fan module 3, - through the pressure chamber 4, - through the filter unit - through the sterilization unit 9, - through the second filter unit 6a, - through the third filter unit 6b, and - out through the outlet 73 of the air cleaner 7 as cleaned air.

It is understood by the skilled person, that each of the above described elements (i.e. fan module 3, pressure chamber 4, filter unit 4, sterilization unit 9, second filter unit 6a, third filter unit 6b) each comprises at least one inlet and at least one outlet to allow air to pass through.

The above described elements may in another embodiment be arranged in a different configuration resulting in a different flow path through the air cleaner.

The air that passes through the air cleaner 7 preferably has an approximately laminar flow path from the point of passing through the pressure chamber 4 and onwards in the air cleaner 7, to ensure a minimal amount of turbulence and thus vibration and noise.

Figure 8a shows a front view of a Biological Safety Cabinet (BSC) comprising a first ventilation device 10 according to the invention and a second ventilation device 100 according to the invention. Figure 8b shows a rear view of the BSC 8 shown in figure 8a.

The first ventilation device 10 is similar to the ventilation device 1 described in relation to figures 4-6, but comprising two fan chambers 20a,b and two fan modules 30a,b (not shown).

The second ventilation device 100 is similar to the ventilation device 1 described in relation to figures 4-6 comprising three fan chambers 2a-c and three fan modules 3a-c (not shown).

The BSC 8 comprises; - a tabletop 81 with air inlet and a work space area 86, - a front window 82, - a control unit 83 for controlling air flow into and from the BSC, - a first ventilation device 10 comprising two fan chambers 20a,b, two fan modules 30a,b (not shown), one pressure chamber 40 and one filter unit 60 with a HEPA filter, - a second ventilation device 100 comprising three fan chambers 2a-c, three fan modules 3a-c (not shown), one pressure chamber 4 and one filter unit 6 with a HEPA filter,

When the BSC is activated outside air from the room where the BSC is located will be pulled into the BSC through the front opening adjacent to the tabletop 81 with air inlet and further through an air channel (not shown) arranged adjacent to a back cover plate 84.

Approximately 30 % of the inlet air will pass through the first ventilation device 10 and exit through an air outlet 87 in the BSC as clean air released back into the room.

Approximately 70 % of the inlet air will pass through the second ventilation device 100 and enter into the work space area 86 as clean air.

The first ventilation device 10 and the second ventilation device 100 are preferably arranged opposite each other, with the pressure chambers 6. 60 of each ventilation device 100,10 facing away from each other, so that the fan chambers 2a-c, 20a-b of each ventilation device are arranged facing towards each other.

Claims (15)

1. Ventilation device (1) for ventilating and cleaning air, the device comprising; - a hollow fan chamber (2) with a fan module (3), the fan module (3) comprising a fan wheel (31) having a hub (32) on which a plurality of fan blades (33) are arranged, said fan module (3) being arranged at least partly in said fan chamber (2) and being adapted to draw outside air into the fan module (3) when the fan module (3) is in an activated configuration, - a filter unit (6) comprising a filter (63) for removing impurities, and - a separate hollow pressure chamber (4) arranged between said fan chamber (2) and said filter unit (6) so as to guide the air from the fan module to a substantial laminar flow into the filter, the fan chamber (2) and the separate pressure chamber (4) have an opening (25, 45) in between them for air flow passage.

2. Ventilation device (1) according to claim 1, wherein; - the hollow fan chamber (2) having an air inlet (23) formed on an inlet wall (21) thereof and an air outlet (25) formed on an outlet side (24) opposite to said inlet wall, wherein a side wall (26) is provided between the inlet and outlet sides, - the separate hollow pressure chamber (4) comprises a chamber upper wall (41) having a perforation (45) and abutting the outlet side (24) of the fan chamber (2), an opposite chamber lower side (43), side walls (49a, b) provided between the chamber upper and lower sides, the upper and lower sides (41, 43) and the side walls (49a, b) defining an internal spacing (48), and - the filter unit (6) comprises a filter inlet wall (61), an opposite filter outlet side (62) and the filter (63) is arranged between said inlet and outlet side, where the filter inlet wall (61) abuts the chamber lower side (43), so that when the fan module is in the activated configuration, outside air is drawn into the fan module through said inlet (23) and guided by said fan chamber through the internal spacing (48) of the pressure chamber (4) and out through the filter unit (6).

3. Ventilation device (1) according to any one of the previous claims, wherein the separate hollow pressure chamber (4) allows unobstructed airflow in the internal spacing (48).

4. Ventilation device (1) according to any one of the previous claims, wherein the fan module (3) is adapted so as to discharge air substantially in the entire circumference of the fan wheel (31).

5. Ventilation device (1) according to any one of the previous claims, wherein the side wall (26) has a substantially circular circumference.

6. Ventilation device (1) according to any one of the previous claims, wherein the inlet wall (21) further comprises a flange (22) extending from said inlet wall (21) into said fan module (3) for guiding outside air into the center of said fan module.

7. Ventilation device (1) according to claim 6, wherein the fan wheel (31) is arranged so as to rotate around at least a part of said flange (22).

8. Ventilation device (1) according to any one of claims 2 - 7, wherein said fan module (3) is arranged adjacent to said perforation (45) so as to partly cover said perforation (45).

9. Ventilation device (1) according to any one of the previous claims, wherein the outlet side (24) of the fan chamber (2) having a circular shape abuts the chamber upper wall (41) so as to partly cover the perforation (45).

10. Ventilation device (1) according to any one of the previous claims, wherein the chamber upper wall (41) comprises at least two perforations (45a-f) arranged adjacent to said fan module (3), said perforations being separated by at least two elongated spacers (46a-f) extending radially from a central wall part (47).

11. Ventilation device (1) according to claim 8, wherein the fan module (3) is attached to said central wall part (47).

12. Ventilation device (1) according to any one of the previous claims, wherein the chamber side walls (49a,b) are substantially parallel with each other.

13. Ventilation device (1) according to any one of the previous claims, wherein the device (1) comprises at least two fan chambers (2a, 2b) and at least two fan modules (3a, 3b).

14. Ventilation device according to any one of the previous claims, wherein the device (1) comprises one pressure chamber.

15. Ventilation device (1) according to any one of the previous claims, wherein the filter unit (6) further comprises a pre-filter (5) arranged between the filter (63) and the pressure chamber (4).