Patent Application
20240068680
The present invention relates to a humidifier comprising a tray for containing water and a nebulizing device for nebulizing water from said tray; an evaporation chamber arranged over at least a portion of said tray, said evaporation chamber terminating at an impactor; and a fan arranged to generate an air flow through said evaporation chamber towards the impactor.
The present invention further relates to an impactor for such a humidifier.
Humidifiers are used to increase the relative humidity in an enclosed space, e.g. in a domestic or business setting. This for instance may be to compensate for humidity loss caused by ventilation or heating systems such as a central heating system, and may be desirable in order to avoid health issues such as dry skin, respiratory discomfort and the like.
A common design of such a humidifier is based on a cold evaporation principle, in which a wick or a similar material acts as a conduit between a water bath and a fan over the water bath, such that water evaporated from the wick gets propelled by the fan into the enclosed space in which the humidifier is positioned. This has the benefit that water vapor rather than larger size water droplets are expelled from the humidifier, but a drawback is that the wick can grow mould and become rather dirty over time, which is hard for a user to clean.
An alternative design of such a humidifier utilizes an ultrasonic transducer in contact with the water bath, in which the ultrasonic transducer generates small droplets and ejects these droplets into the air stream generated by the fan that spreads these droplets into ambient, where they can evaporate. This design does not significantly suffer from mould growth or other fouling, but has the disadvantage that contaminants in the water within the water bath are ejected within the water droplets into ambient, which is unhygienic. For example, A. E. Sain et al. in: “Size and mineral composition of airborne particles generated by an ultrasonic humidifier”, Indoor Air, Volume 28(1), 2018, pages 80-88 (doi10:1111/ina.12414) describe the results of a study on the size distribution and concentration of particles expelled by a portable, 3 L ultrasonic humidifier. The ultrasonic humidifier was filled with waters of varying mineral content and hardness. Aerosol size distributions were measured during 8 h of humidifier operation in a typical bedroom. It was found that lower mineral waters produced fewer, smaller particles when compared to higher mineral waters. Chemical analyses of particles collected with a cascade impactor indicated that the minerals in emitted particles had the same relative mineral concentrations as the fill water, thus demonstrating that ultrasonic humidifiers should be considered a source of inhalation exposure to minerals dissolved in water, and that the magnitude of exposure to inhalable particles will vary with water quality. Although such exposure risks may be avoided by the use of filtered or distilled water, in practice most users tend to fill such humidifiers with tap water, thereby exposing people sharing a room with the humidifier when in operation to the mineral content in the tap water.
CN 207094797 discloses an air treatment module which has a water tank, a shower head above the water tank in a spray chamber, a pump to deliver water to the shower head and a fan assembly on top of the spray chamber. A water retaining plate is fitted before the fan assembly to avoid water droplets reaching the fan motor.
The present invention seeks to provide a humidifier that can operate using tap water whilst reducing the mineral content expelled by the humidifier.
The present invention further seeks to provide an impactor for use with such a humidifier.
According to an aspect, there is provided a humidifier comprising a water containing arrangement for containing water and a nebulizing device for nebulizing water from said water containing arrangement; an evaporation chamber arranged over at least a portion of said water containing arrangement, said evaporation chamber terminating at an impactor; and a fan arranged to generate an air flow through said evaporation chamber towards the impactor; wherein the impactor comprises an inner body having a plurality of apertures, and an outer body having a plurality of further apertures fluidly connected to said apertures, wherein said further apertures are offset relative to said apertures such that each aperture in the inner body faces a section of a material of the outer body that is spatially separated from said aperture.
The outlet flow from the fan enters the evaporation chamber at an entrance to the evaporation chamber and the flow drives through the evaporation chamber towards the impactor at the exit from the evaporation chamber.
The design of the impactor ensures that water vapor can escape the humidifier whereas (larger) droplets are caught by the impactor and prevented from escaping the humidifier. Consequently, contamination captured in such water droplets is prevented from escaping the humidifier, thereby reducing the health risks for people exposed to the humid air released from the humidifier. This is achieved due to the fact that the apertures in the inner body of the impactor speed up the air flow generated by the fan, causing a jet effect, which air jet is then diverted around the material portions of the outer body facing the apertures of the inner body owing to the fact that the further apertures are offset relative to the apertures. Due to the mass of water droplets passing through the apertures, the moment of inertia of these water droplets causes the droplets to collide with the material portions in the outer body facing such apertures, thereby capturing the water droplets and preventing them from exiting the impactor through the further apertures.
The plurality of apertures may be arranged in a plurality of spatially separated linear arrays of apertures and the plurality of further apertures may be arranged in a plurality of linear channels extending in the same direction as said linear arrays. As the further apertures simply provide exits from the impactor, they may be arranged as channels, thereby simplifying manufacturing complexity of the impactor and reducing its manufacturing cost.
In an embodiment, each section of said material of the outer body comprises a pair of opposing side walls extending along said linear channels towards the inner body. This further improves the effectiveness of the material sections in capturing water droplets due to an increased surface area of the material section and a reduced width of the fluid path between the apertures and the further apertures due to the side wall extending into this fluid path.
The impactor may have any suitable shape. For example, the impactor may have a cuboid or a cylindrical shape, which shape typically matches the shape of the housing of the humidifier.
The impactor may further comprise a plurality of drainage holes, each drainage hole being arranged to drain water collected by a section of the material of the outer body from the impactor. This ensures continuing functioning of the impactor, as the build-up of excessive water within the impactor due to the collection of water droplets by the material sections of the second body, which could impede the air flow from the apertures to the further apertures, is avoided.
To this end, the humidifier may further comprise at least one drainage channel extending from the impactor towards the water containing arrangement, wherein said drainage holes are aligned with said at least one drainage channel such that water trapped by the impactor can be reintroduced into the nebulizing device, e.g. via the water reservoir.
The inner body and the outer body of the impactor may extend in the same direction as said at least one drainage channel or may extend across the evaporation chamber. In other words, the impactor may be positioned in a vertical orientation, in which the further apertures are offset relative to the apertures in a vertical direction or the impactor may be positioned in a substantially horizontal orientation, in which the further apertures are offset relative to the apertures in a horizontal direction. In the latter embodiment, the inner and outer bodies preferably are curved or angled such that water droplets captured by the impactor can flow towards the sides of the impactor in order to facilitate draining of the water droplets from the impactor through its drainage holes.
The inner body and the outer body preferably are made of or coated with a hydrophobic material to promote the drainage of collected water droplets from the impactor.
In an embodiment, the water containing arrangement comprises a water tray in fluid communication with a water reservoir, with the nebulizing device being positioned in the water tray. This has the advantage that the water volume contained by the humidifier is increased, thus allowing for prolonged continuous operation before the humidifier needs to be replenished with water. The water reservoir may be in fluid communication with the water tray through a valve such as for instance a float valve responsive to a water level in the water tray or a solenoid valve such that a substantially constant water level can be maintained in the water tray.
In a preferred embodiment, the nebulizing device comprises a piezoelectrically actuated mesh structure for forming water droplets from the water in said water containing arrangement and expelling the formed water droplets into the evaporation chamber, as this allows for the formation of water droplets with a well-controlled droplet size, as the droplet size is typically governed by the size of the holes in the mesh. The mesh may be controlled by an actuator, which actuator may be configurable to adjust a vibration frequency, duty cycle and amplitude of the piezoelectric actuated mesh structure such that the rate at which water droplets are expelled by the mesh structure can be adjusted. For example, the nebulizing device may have a minimum water droplet expulsion rate of 1.6 L/h, which may be increased through control of the actuator.
In an example embodiment, the piezoelectrically actuated mesh structure is arranged over a chamber having a water inlet, said chamber comprising a sponge material arranged to transport water from the water inlet to the piezoelectrically actuated mesh structure to ensure a continuous water supply to the mesh structure. The sponge material may be removable from said chamber in order to clean or replace the sponge when necessary, e.g. for hygienic reasons. The chamber may further comprise a spring that compresses the sponge against the mesh structure to further ensure a continuous water supply to the mesh structure.
In accordance with another aspect, there is provided an impactor for use in the humidifier of any of the herein described embodiments, the impactor comprising an inner body having a plurality of apertures, and an outer body having a plurality of further apertures fluidly connected to said apertures, wherein said further apertures are offset relative to said apertures such that each aperture in the inner body faces a section of a material of the outer body that is spatially separated from said aperture. Such an impactor may be used with any type of humidifier that generates water droplets rather than water vapor and drives these water droplets to ambient with a fan, as the impactor when placed in the air stream generated by the fan that carries the water droplets can remove the water droplets from this air stream prior to exiting the humidifier, thus leaving only evaporated water in this air stream as explained in more detail above.
The plurality of apertures may be arranged in a plurality of spatially separated linear arrays of apertures and the plurality of further apertures may be arranged in a plurality of linear channels extending in the same direction as said linear arrays to yield an impactor having a simple design that can be manufactured in a cost-effective manner.
The impactor may further comprise a plurality of drainage holes, each drainage hole being arranged to drain water collected by a section of the material of the outer body from the impactor to ensure that collected water droplets are not retained by the impactor.
Embodiments of the invention are described in more detail and by way of non-limiting examples with reference to the accompanying drawings, wherein:
It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.
A sensor (not shown) may be positioned in the water reservoir 70 or the tray 14, which sensor is adapted to monitor a water level in the water reservoir 70 or the tray 14 such that a controller (not shown) responsive to the sensor can cause the generation of an alert to alert a user of the humidifier 10 that the tray 14 or the water reservoir 70 needs replenishing. Such an alert may be generated in any suitable manner, and as the generation of such alerts is well-known per se, this will not be explained in further detail for the sake of brevity only. The water containing arrangement may be fluidly coupled to a mains water supply, e.g. through a float valve or the like to maintain a relatively constant volume of water in the water containing arrangement. Alternatively, a user may be required to manually top up the water containing arrangement.
A nebulizing device 20 is positioned in the tray 14 and is adapted to nebulize water from the tray 14 into water droplets that are expelled by the nebulizing device 20 into the evaporation chamber 16 that is arranged over at least a part of the tray 14 containing the nebulizing device 20. A fan 80, e.g. a centrifugal fan or axial fan, is arranged to draw air into the humidifier 10 through air inlets 82, which may be arranged in any suitable location, e.g. in the bottom of the humidifier 10 and/or in a side wall of the housing 11 of the humidifier 10. The fan 80 is fluidly connected to the evaporation chamber 16, e.g. through a conduit 84, and is adapted to generate an air stream as indicated by the block arrows through the evaporation chamber 16 in a direction from the tray 14 including the nebulizer 20 towards an impactor 40 under a roof 12 of the humidifier 10 through which the air stream is expelled into the ambient surroundings of the humidifier 10. During transport from the nebulizing device 20 to the impactor 40, at least some of the water droplets generated by the nebulizing device 20 may at least partially evaporate in the evaporation chamber 16 before reaching the impactor 40. In example embodiments, the fan 80 produces an air flow at a rate of 150-250 m3/h although other air flow rates are equally feasible depending on the size and application domain of the humidifier 10.
The nebulizing device 20 may be any suitable type of nebulizing device. In an example embodiment, which is schematically depicted in
The actuator 21 may be adapted to vary the vibration frequency and amplitude of the piezoelectric mesh 22, which for example may be achieved by varying the voltage or pulse width supplied by a pulse width modulated actuator 21. To this end, the humidifier 10 may have a user interface (not shown) through which a user can set a water nebulization rate of the nebulizing device 20, directly or indirectly, which rate setting translates to a corresponding adjustment of the vibration frequency, amplitude or duty cycle of the piezoelectric mesh 22. In an example embodiment, the water nebulization rate of the nebulizing device 20 is at least 1.6 L/h to ensure sufficient humidifying of an enclosed space, e.g. a room or the like, in which the humidifier 10 is to be placed.
In an example embodiment schematically depicted in
As explained above, the nebulizing device 20 produces water droplets 92 that are carried by the air stream produced by the fan 80 through the evaporation chamber 16 during which the water droplets 92 may at least partially evaporate during transport through the evaporation chamber 16. At the end of the evaporation chamber 16 distal to the tray 14, an impactor 40 is arranged that is adapted to capture the water droplets 92 that are still present in the air stream at that point. The impactor 40, which is schematically depicted in
The impactor 40 further comprises an outer body 50 arranged such that the inner body 50 is located in between the evaporation chamber 16 and the outer body 60. The outer body 60 comprises a plurality of further apertures 64 in the material 62 of the outer body 60, which further apertures 64 are offset relative to the apertures 54 such that each aperture 54 faces a material section 52 of the outer body that is spatially separated from the aperture 54. The inner body 50 and the outer body 60 are typically arranged such that each aperture 54 is fluidly coupled to at least one of the further apertures 64, that is, an air flow path exists between each aperture 54 and at least one of the further apertures 64, e.g. by spatially separating the inner body 50 from the outer body 60. In operation, when the air stream generated by the fan 80 (as indicated by the curved arrows) is forced through the apertures 54 of the inner body 50, the air stream is accelerated due to this force caused by the relatively small dimensions of the apertures 54, and diverted once the air stream has passed through the apertures 54 due to the offset positioning of the further apertures 64 relative to the apertures 54, as indicated by the curved arrows in
The material sections 62 of the outer body 60 may further comprise one or more sidewalls 63 extending along the further apertures 64 towards the inner body 50 to improve the droplet capturing capability of the outer body 60. Although such sidewalls 63 preferably are spatially separated from the inner body 50, one of the sidewalls 63 of each material section 62 may instead extend onto the inner body 50, e.g. to strengthen the impactor 40, in which case each aperture 54 is typically connected to one or more further apertures 64 on one side of such a material section 62 only.
The values in Table 1 are applicable for an impactor 40 used in a humidifier deploying a nebulizing device 20 producing water droplets having a diameter in a range of 30-40 μm and a fan 80 producing an air flow rate of around 170-200 m3/h. Of course, it will be readily understood by the skilled person that the values of these parameters are shown by way of non-limiting example only, and may readily be adjusted if at least one of the droplet size produced by the nebulizing device 20 and the air flow rate produced by the fan 80 is adjusted.
Now, upon returning to
In
In the foregoing embodiments, the nebulizer 20 is positioned in the water tray 14, which is in fluid communication with the water reservoir 70. However, in an alternative embodiment schematically depicted in
In the foregoing description, the impactor 40 is shown as part of the humidifier 10. However, it should be understood that the impactor 40 may be provided as a standalone item, e.g. as a consumable, and may be used in conjunction with existing humidifiers, e.g. ultrasonic humidifiers, such that the expulsion of water droplets by such humidifiers is prevented by the addition of the impactor 40.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/CN2020/136883 | Dec 2020 | WO | international |
| 21153175.1 | Jan 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/085327 | 12/10/2021 | WO |
