Moisture absorbent for drying in dehumidification units

Abstract

In an appliance configured to blow air, a dehumidifying unit 50 is used to ensure that the air expelled from the appliance is dry air. This is particularly advantageous when the air is used for drying purposes such as drying hair. The dehumidifying unit 50 is configured to allow an air flow to pass and to dehumidify the air flow, the dehumidifying unit 50 comprising a desiccant 56 and a heater 51, the heater 51 having a wall structure 52 including at least one compartment 55, the desiccant 56 being disposed in at least one such compartment 55. Advantageously, the heater 51 of the dehumidifying unit 50 is activated for a limited period of time after each time the appliance is operated with an air flow output.

Description

Technical Field

[0001] The present invention relates to a dehumidifying unit used in an appliance having a housing and an air flow generating unit configured to generate an air flow from an air inlet region of the housing to an air outlet region of the housing. The dehumidifying unit is configured to allow the air flow to pass therethrough and dehumidify the air flow, and the dehumidifying unit has a desiccant and a heater.

Background Art

[0002] A practical example of an appliance having a housing and an air flow generating unit configured to generate an air flow from an air inlet region of the housing to an air outlet region of the housing is a hair dryer. Generally, the purpose of a dryer is to change hair from a wet / moist state to a dry state. The lower the humidity level of the air, the shorter the time required to dry the hair. From such a perspective, it is advantageous for a blow dryer to be provided with a dehumidifying unit.

[0003] JPH05228012A discloses a hair dryer configured to blow low-humidity air onto hair, and as a result, the hair drying process is effective. A known hair dryer has an impeller provided with a regeneration heater at its center, a plurality of blades arranged on the outer periphery of the impeller, a dry air passage, a regeneration air passage, a drying heater provided at a discharge port of the dry air passage, a switching plate for switching between the dry air passage and the regeneration air passage, and a switch. In order to absorb moisture in the air, a dehumidifying agent such as silica gel is supported on the blades arranged on the outer periphery of the impeller.

[0004] The switch can set three states of the hair dryer, namely, power off, drying, and regeneration. In the drying state of the hair dryer, the switching plate guides the air flow induced by the impeller to the dry air passage while being in a position to close the regeneration air passage against the air flow. In the regeneration state of the hair dryer, the switching plate guides the air flow induced by the impeller to the regeneration air passage while being in a position to close the dry air passage against the air flow.

[0005] When a user of a hair dryer wants to dry their hair with the hair dryer, they operate a switch to set the dry state of the hair dryer. The impeller rotates, so that air is sucked in and passes through the silica gel carried by the impeller. The silica gel absorbs moisture from the air, so that the air is dehumidified. The dehumidified air is pushed by the impeller and moves to the outer periphery of the impeller under the influence of centrifugal force caused by the rotation of the impeller. The dehumidified air further flows along the dry air passage and is heated by the dry heater to a relatively low temperature that is safe for hair. Finally, the dehumidified air is discharged from the discharge port of the dry air passage.

[0006] Silica gel is almost colorless in a dry state, but when it absorbs moisture from the air, it gradually changes to blue and red. Through the notch present in the hair dryer for introducing air into the impeller, the user can check the color of the silica gel on the impeller blades, and thus can determine the moisture absorption state of the silica gel at a glance. When the user confirms that the color of the silica gel is blue or even red, the user uses the switch to put the hair dryer into a regenerative state. As mentioned above, in the regenerative state of the hair dryer, the switching plate is in a position to direct the air flow induced by the impeller into the regenerative air passage, while closing the dry air passage to the air flow. Furthermore, the impeller is rotated, and the regenerative heater is powered to achieve a high temperature of the central shaft of the impeller. As a result, the moisture absorbed by the silica gel evaporates. Due to the effect of the rotating impeller, the air carrying the evaporated moisture is forced to move away from the impeller and flow through the regenerative air passage, and finally discharged from the exhaust port of the regenerative air passage. As a result of the regeneration process, in which the impeller is rotated and the regeneration heater is turned on, the silica gel is returned to a dry state and is ready to efficiently absorb moisture from the air in the next drying process. Summary of the Invention [Problem to be solved by the invention]

[0007] A disadvantage of the hair dryer known from JPH05228012A is that the effectiveness of the drying process, as explained, depends on an action by the user, i.e. checking the color of the silica gel and, if appropriate, operating the hair dryer in regenerative mode. Another disadvantage is that the regenerative heater needs to generate a large amount of heat in order to bring the silica gel present on the impeller blades to a temperature high enough to evaporate the water contained in the silica gel.

[0008] It is an object of the present invention to provide a dehumidification unit designed such that the dehumidification unit is compact and robust, and the desiccant can be effectively regenerated at relatively low temperatures without necessarily relying on user action to initiate the regeneration process. [Means for solving the problem]

[0009] The present invention provides a dehumidification unit for use in an appliance having a housing and an airflow generating unit configured to generate an airflow from an air inlet region of the housing to an air outlet region of the housing, the dehumidification unit being configured to allow the airflow to pass through and to dehumidify the airflow, the dehumidification unit having a desiccant and a heater, the heater having a wall structure including at least one compartment, and the desiccant being disposed in the at least one compartment.

[0010] From the above definition, in the dehumidifying unit according to the invention, the heater has a dual function, i.e. the first function of heating and the second function of containing the desiccant. Advantages of the specific design of the heater wall structure with at least one compartment include allowing the dehumidifying unit to be compact and robust, which is highly desirable in handheld appliances such as hair dryers, and the close arrangement of the heater and the desiccant allows the heat generated by the heater to be transferred to the desiccant in the most efficient manner.

[0011] According to a practical option present in the context of the present invention, the heater wall structure comprises at least two compartments. In that case, the desiccant may be arranged in all of said at least two compartments, but this is not necessary. For example, the heater wall structure can have a grid of strips and a strip containing a grid of strips. Another possibility is that the heater wall structure has a honeycomb shape, with honeycomb-shaped cells constituting said at least two compartments in the wall structure.

[0012] The heater can be of any suitable type. According to one possible example, the heater comprises a positive temperature coefficient (PTC) material. With regard to the above mentioned possibility that the wall structure of the heater has a honeycomb shape, the heater may be a honeycomb PTC heater, where it is noted that compared to the conventional designs of such type of heater, the design of the heater may need to be adjusted to have cells large enough to contain the desiccant.

[0013] It is a commonly known fact that a PTC heater usually has at least one piece of PTC material, said at least one piece of PTC material sandwiched between a pair of electrodes that connect to a metal (silver) coating on the PTC material. When a voltage is applied to the piece of PTC material, the PTC material generates heat. In this process, the temperature is controlled based on a self-regulating mechanism, because PTC material has the property that the internal resistance increases as the temperature increases. In this way, it is achieved that the temperature is kept below the maximum temperature related to the exact composition of the PTC material.

[0014] According to another possible embodiment, the heater is a ceramic heater. An advantageous aspect of applying a ceramic heater is that it is not necessary to have electrodes on the opposite side of the heater. Instead, the ceramic heater has a heater track embedded inside. Thus, the ceramic heater occupies a minimum of space. To limit the temperature of the ceramic heater, any suitable additional elements can be used, such as an external temperature sensor, a microprocessor that controls the temperature based on the input from the sensor, and a mechanical temperature-sensitive switch near the heater to cut off the power supply to the heater in case of failure of the microprocessor or failure of the electrical circuit with the sensor, microprocessor and heater.

[0015] In a practical embodiment, the dehumidifying unit comprises two breathable covers, between which at least a part of the wall structure of the heater is sandwiched, for example the covers comprising a sheet with holes, where, optionally, the covers comprise a plastic material, such as a nylon material, capable of withstanding the heat generated by the heater during operation.

[0016] In the context of the present invention, any suitable type of desiccant can be applied. According to one of the many practical possibilities, the desiccant is of the type comprising silica gel beads.

[0017] The invention further relates to an appliance comprising a housing, an airflow generating unit configured to generate an airflow from an air inlet area of ​​the housing to an air outlet area of ​​the housing, and a dehumidifying unit as defined and described above. It is advantageous if the dehumidifying unit is arranged near the air inlet of the housing. It is also advantageous if the dehumidifying unit is configured to cover the entire air inlet area, such that the desiccant spreads over the entire air inlet area, so that substantially all of the incoming air can actually be dehumidified.

[0018] The appliance may further include an airflow heater located downstream of the dehumidification unit as viewed in a direction from the air inlet area of ​​the housing toward the air outlet area of ​​the housing. The airflow heater functions to heat the outgoing air to a desired temperature and may be activated during operation of the appliance as a default or based on input provided by a user. The airflow heater may be configured to generate a greater amount of heat than the heater of the dehumidification unit.

[0019] The efficient utilization of the dehumidification unit is always maintained when the heater of the dehumidification unit is automatically activated after each dehumidification operation on the air flow, in order to dry the desiccant so that it is available for the next dehumidification operation. In view of this, it is advantageous if the above-mentioned appliance comprises a controller programmed to keep the heater of the dehumidification unit in an inoperative state when the appliance is put into a state of outputting an air flow, and to activate the heater of the dehumidification unit for a limited period of time when the appliance is returned from a state of outputting an air flow to an inoperative state. In the case where the appliance has the above-mentioned air flow heater, it is particularly advantageous if the controller is programmed to activate the air flow heater while keeping the heater of the dehumidification unit in an inoperative state when the appliance is put into a state of outputting hot air, and to deactivate the air flow heater when the appliance is returned to an inoperative state, at which point the heater of the dehumidification unit is activated for a limited period of time.

[0020] A practical example of the appliance as defined and described above is a hair dryer. In a more general sense, the appliance may be any household appliance or personal care appliance.

[0021] The above-mentioned and other aspects of the invention will be apparent from and elucidated with reference to the following detailed description of embodiments of a hair dryer with a dehumidifying unit and a dehumidifying unit. [Brief description of the drawings]

[0022] [Figure 1]FIG. 2 diagrammatically illustrates a hair dryer according to an embodiment of the present invention having a dehumidifying unit. [Diagram 2] FIG. 1 shows diagrammatically elements of a dehumidification unit according to a first embodiment of the invention. [Diagram 3] FIG. 4 shows a schematic diagram of a heater of a dehumidification unit according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The invention will now be explained in more detail with reference to the figures, in which equivalent or similar parts are designated with the same reference numbers.

[0024] Fig. 1 shows a hair dryer 100 according to an embodiment of the present invention, as an example of an appliance within the scope of the present invention. It should be noted that for clarity, Fig. 1 is of a schematic nature only, showing the various elements of the hair dryer 100 in a simplified manner.

[0025] The hair dryer 100 is a handheld device intended to be applied by a user to dry the hair with a stream of (hot) air. In this example, the hair dryer 100 comprises: a handle 10 enabling a user to hold the hair dryer 100 in his / her hand; a housing 20 having an air inlet 21 and an air outlet 22, the housing 20 being practical if it has a generally circular or elliptical periphery, and more practical if the air inlet area 22 comprises a plurality of relatively small holes and the air outlet area 22 comprises a single relatively large opening; an air flow generating unit 30 functioning to generate an air flow from the air inlet region 21 of the housing 20 to the air outlet region 22 of the housing 20, the air flow generating unit 30 having a rotatable impeller 31; an airflow heater 40 which serves to heat the airflow in the housing 20, during which hot air is blown from the hair dryer 100 while the airflow heater 40 is activated, the airflow heater 40 being, for example, a wire heater supported on a mica frame; a dehumidification unit (50) which serves to dry the air flow in the housing (20) to ensure that the air blown out of the hair dryer (100) is dry air; a microcontroller 60 which serves as the controller for the operation of the hair dryer 100; For example, the hair dryer 100 may have a switch 70 operable by a user to set the state of the hair dryer 100 to a hot air blowing state, a cold air blowing state, or a non-operating state.

[0026] In this example, a practical arrangement of the dehumidifying unit 50 in the housing 20 is shown, that is, the dehumidifying unit 50 is located near the air inlet area 21 of the housing 20. In particular, in this example, the air drawn into the housing 20 under the influence of the rotating impeller 31 during the operation of the hair dryer 100 passes through the dehumidifying unit 50, the impeller 31, and the air flow heater 40 in sequence before leaving the housing 20. In the process, the air is dried at the position of the dehumidifying unit 50, and the air is then heated at the position of the air flow heater 40 if the state of the hair dryer 100 set by the user includes the operation of the air flow heater 40. It is advantageous for the hair dryer 100 to blow dehumidified air in order to effectively perform the desired hair drying function. Without the dehumidifying unit 50 and without drying the air, the hair drying process takes time, and this is even more so when the hair dryer 100 is operated in a relatively wet environment such as a bathroom where the user has just taken a shower or a bath. The direction of airflow through housing 20 is indicated by arrows in FIG.

[0027] In general, the dehumidifying unit 50 comprises a desiccant and a heater. The airflow passing through the dehumidifying unit 50 is dehumidified under the effect of the interaction between the air and the desiccant. The heater serves to regenerate the desiccant by evaporating absorbed moisture. Advantageously, the microcontroller 60 is programmed to activate the heater of the dehumidifying unit 50 for a limited period of time each time a hair drying operation is performed and finished. This ensures that the moisture absorption capacity of the desiccant is optimal at the start of the hair drying operation. It is assumed that the user will leave the hair dryer 100 connected to the mains in order to regenerate the desiccant. On the other hand, the hair dryer 100 may also be equipped with a (rechargeable) battery capable of providing enough power to allow the regeneration operation to be performed without being connected to the mains.

[0028] Elements of a dehumidifying unit 50 according to a first embodiment of the invention are shown in FIG. 2. A salient feature of this embodiment is that the wall structure 52 of the heater 51 of the dehumidifying unit 50 comprises a grid of strips 53 and a strip 54 surrounding the grid of strips 53, which is bent in a circular shape in this example. In the grid of strips 53, compartments 55 are defined, and a desiccant 56 is present in at least a selection, preferably all, of these compartments 55, as shown in FIG. 2. In FIG. 2, the desiccant 56 is depicted as a collection of beads. A practical example of a material for the heater 51 is a positive temperature coefficient (PTC) material, and a practical example of the desiccant 56 is silica gel, which may be provided in beads.

[0029] The dehumidification unit 50 according to the first embodiment of the present invention further comprises two covers 57, 58 closing opposite sides of the heater 51 filled with desiccant 56. The covers 57, 58 have sheets with holes 59 through which air can pass. It should be understood that the holes 59 are small enough to enable the covers 57, 58 to hold the desiccant 56 in separate compartments 55 in the wall structure 52 of the heater 51. Brackets or the like can be used to hold the covers 57, 58 in place on the heater 51.

[0030] A heater 51 of a dehumidification unit 50 according to a second embodiment of the present invention is shown in Figure 3. Except for the design of the heater 51, the dehumidification unit 50 according to the second embodiment of the present invention may be similar to the dehumidification unit 50 according to the first embodiment of the present invention.

[0031] The wall structure 52 of the heater 51 of the dehumidification unit 50 according to the second embodiment of the invention has a honeycomb shape, the cells of which constitute the compartments 55 housing the desiccant 56. In fact, the heater 51 is a modified honeycomb PTC heater, i.e. a honeycomb PTC heater with enlarged cells to accommodate the desiccant. The invention covers the use of alternative types of heaters, such as ceramic heaters, and essentially the heater 51 can be made of any suitable type of material or any suitable combination of materials.

[0032] In any of the above described embodiments, it is sufficient to operate the heater 51 at a temperature significantly lower than the temperature produced by the airflow heater 40 of the hair dryer 100 during operation in order to remove absorbed moisture from the desiccant 56.

[0033] The scope of the present invention is not limited to the above examples, and it will be apparent to those skilled in the art that several modifications and changes can be made thereto without departing from the scope of the present invention defined in the appended claims. It is intended that the present invention be construed as including all such modifications and changes insofar as they are within the scope of the claims or their equivalents. Although the present invention has been illustrated and described in detail in the drawings and description, such illustrations and descriptions are merely explanatory or exemplary and not restrictive. The present invention is not limited to the disclosed embodiments. The drawings are schematic, in which details that are not necessary for understanding the present invention may be omitted and are not necessarily drawn to scale.

[0034] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the figures, the description, and the appended claims. In the claims, the word "comprising" does not exclude other steps or elements, and the indefinite article "a" or "an" does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope of the invention.

[0035] Elements and aspects discussed for or in connection with a particular embodiment can be combined with elements and aspects of other embodiments as appropriate, unless otherwise expressly stated. Thus, 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.

[0036] The terms "having" and "including" as used herein will be understood by those skilled in the art to cover the term "consisting of." Thus, the terms "having" or "including" may mean "consisting of" in one embodiment, but may mean "including / having / comprising at least the specified species and, optionally, one or more other species" in another embodiment.

[0037] For the sake of completeness, the terms "dehumidification" and "drying" as used herein should be understood to have similar meanings. Furthermore, any reference herein to a process for regenerating the desiccant 56 should be understood as a reference to a process for dehumidifying the desiccant 56.

[0038] Notable aspects of the invention can be summarized as follows: In an appliance 100 configured to deliver air, a dehumidifying unit 50 is used to ensure that the air delivered from the appliance 100 is dry air. This is particularly advantageous when the air is used for drying purposes such as drying hair. The dehumidifying unit 50 is configured to allow an air flow to pass and to dehumidify the air flow, the dehumidifying unit 50 comprising a desiccant 56 and a heater 51, the heater 51 having a wall structure 52 including at least one compartment 55, the desiccant 56 being disposed in the at least one compartment 55. Advantageously, the heater 51 of the dehumidifying unit 50 is activated for a limited period of time every time after the appliance 100 is operated in a state where it outputs an air flow.

Claims

1. 1. A dehumidifying unit for use in an appliance having a housing and an airflow generating unit that generates an airflow from an air inlet area of ​​the housing to an air outlet area of ​​the housing, the dehumidifying unit allowing an airflow to pass therethrough and dehumidifying the airflow, the dehumidifying unit having a desiccant and a heater, the heater having a wall structure including at least one compartment, and the desiccant disposed in the at least one compartment.

2. The dehumidifying unit of claim 1 , wherein the heater wall structure includes at least two compartments, and the desiccant is disposed in at least one of the at least two compartments.

3. The dehumidification unit of claim 2 , wherein the desiccant is disposed in all of the at least two compartments.

4. 4. A dehumidifying unit according to claim 2 or 3, wherein the heater wall structure comprises a grid of strips and a strip containing the grid of strips.

5. the wall structure of the heater has a honeycomb shape; 4. A dehumidifying unit according to claim 2 or 3, wherein the honeycomb-shaped cells constitute the at least two compartments in the wall structure.

6. 6. A dehumidifying unit according to any preceding claim, wherein the heater is a positive temperature coefficient heater or a ceramic heater with a heater track embedded therein.

7. 7. A dehumidifying unit as claimed in any preceding claim, comprising two breathable covers, at least a portion of the heater wall structure being sandwiched between said covers.

8. 8. The dehumidifying unit of claim 7, wherein the cover comprises a sheet with holes.

9. 9. A dehumidifying unit according to claim 7 or 8, wherein the cover comprises a plastics material.

10. 10. A dehumidifying unit according to any preceding claim, wherein the desiccant comprises silica gel beads.

11. 11. An appliance comprising a housing, an air flow generating unit for generating an air flow from an air inlet area of ​​the housing to an air outlet area of ​​the housing, and a dehumidifying unit according to any one of claims 1 to 10.

12. 12. The apparatus of claim 11, further comprising an airflow heater disposed downstream of the dehumidifying unit in a direction from the air inlet area of ​​the housing toward the air outlet area of ​​the housing.

13. 13. An appliance according to claim 11 or 12, comprising a controller programmed to keep a heater of the dehumidifying unit in a deactivated state when the appliance is in a state in which it outputs an airflow, and to activate the heater of the dehumidifying unit for a limited period of time when the appliance returns to a deactivated state from a state in which it outputs an airflow.

14. 14. A device according to any one of claims 11 to 13, which is either a household device or a personal care device.

15. 15. The device of claim 14 which is a hair dryer.

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