Room fragrance device

Description

[0001] The present invention relates to a room fragrance device.

[0002] Various devices and methods exist for releasing a fragrance into a room. The type and size of the room to be scented play a crucial role. For example, disposable air fresheners have been used for many decades to release fragrances into vehicle interiors. In their simplest form, these air fresheners are pre-treated porous bodies that release odor-neutralizing substances after their packaging has been partially or completely removed.

[0003] For scenting large rooms or entire buildings, permanently installed systems are used. These can be designed as part of the building's ventilation system and, for example, introduce the fragrance into the supply air. However, such systems can also be designed independently of the ventilation system and, for example, consist of a system of nozzles through which a fragrance is sprayed directly into the room(s) to be scented.

[0004] Another area of ​​application is the scenting of small to medium-sized rooms, such as individual shops. For this purpose, so-called room scenting devices are generally used, which are not permanently installed. A number of such room scenting devices are described in the prior art.

[0005] WO 96 / 31741 refers to a room fragrance device housed in a compact casing. This casing has an air inlet at the bottom and an air outlet at the top. A fan is installed inside the casing to create a vertical airflow. The airflow generated by the fan passes over an evaporation element with a liquid evaporation surface. A reservoir containing a fragrance liquid is also located inside the casing. The fragrance is dispensed onto the liquid evaporation surface via a special metering valve controlled by a control unit.

[0006] However, such devices have the problem that the liquid can potentially leak when the reservoir is replaced or refilled. This makes them unsuitable for home use and / or for use by untrained personnel. Furthermore, the metering valve in the device described above is relatively complex. There is also a risk that the valve will become contaminated or blocked by non-volatile components in the fragrance. This necessitates regular maintenance and cleaning of the metering valve. A similar problem arises with regard to the evaporator, on whose evaporation surface the non-liquid residues of the fragrance liquid inevitably accumulate. Regular replacement or cleaning of the evaporator is therefore required, which may only be possible for qualified personnel.Furthermore, with such room fragrance devices it is not possible to switch from one fragrance composition to a second fragrance composition without cleaning the device or accepting contamination of the second fragrance composition.

[0007] Document WO 2010 / 132565 A1 discloses a liquid dispenser for a volatile composition for use in a vehicle.

[0008] Document WO 2013 / 149285 A1 discloses an air purification device that kills germs in an airflow.

[0009] Document WO 2013 / 188499 A2 discloses a dispensing device comprising a housing, a blower and an annular reservoir.

[0010] Document WO 2014 / 145372 A1 discloses a device with a refillable or replaceable container for releasing an odor-controlling substance into an environment.

[0011] Document WO 2006 / 113254 A1 discloses a non-energized delivery system for the release of volatile substances into the atmosphere.

[0012] Document WO 2012 / 104351 A1 reveals a function button for a fragrance container.

[0013] Document WO 2015 / 052215 A1 discloses a fragrance dispensing device for a motor vehicle with an airflow duct having a fresh air inlet, a fragrance outlet and at least one opening arranged between the air inlet and the outlet.

[0014] Document EP 2 564 878 A1 discloses a dispenser capable of dispensing a fluid via a vertically oriented piezoelectric device.

[0015] Document EP 1 442 754 A1 discloses a device for releasing steam into the environment.

[0016] Document US 2010 / 314465 A1 discloses a mechanism for modifying the ambient air, such as a fragrance dispenser.

[0017] Document US 2005 / 175513 A1 discloses a device that uses a heat source to heat and distribute fragrant or insecticidal oils.

[0018] Document GB 777 795 A discloses a device for dispensing substances from a storage container using a grease pen.

[0019] Document DE 32 43 731 A1 discloses a device for dispensing flowable substances from a storage vessel.

[0020] It is therefore the object of the present invention to overcome the disadvantages of the prior art.

[0021] In particular, an object of the invention is to create a compact room fragrance device for scenting small to medium-sized rooms that is easy to use and reliable in operation. The device should be as mobile as possible, easy to transport, and flexible in its application. It should enable efficient fragrance distribution with precise control of the fragrance intensity, which should also be as constant as possible if required. The room fragrance device should have a simple design and be discreetly placed in the room to be scented. Furthermore, the device should be suitable for integration into ventilation systems, particularly in vehicles.

[0022] These tasks are solved by a room fragrance device which has the features in claim 1.

[0023] The room fragrance device comprises an air duct with an air inlet and an air outlet, as well as a blower for conveying air through the air duct from the air inlet to the air outlet. Furthermore, the room fragrance device includes a replaceable container for a fragrance liquid and a dosing device for the liquid with a dosing unit. The room fragrance device also includes an evaporation element located within the air duct, whereby the liquid can be conveyed from the replaceable container to the evaporation element by means of the dosing unit. The dosing unit is at least partially located in or on the replaceable container and is replaceable together with it.

[0024] The swap body is at least partially made of a liquid-impermeable material, preferably a material that is also gas-impermeable. Such a material can be, in particular, a metal, preferably an aluminum alloy.

[0025] Because the interchangeable container and the dosing unit are designed as a single, integrated module, there's no need to connect the container to the dosing unit when inserting it into the device. This significantly reduces the risk of accidental spills. Furthermore, the dosing unit is replaced every time the container is changed, eliminating the need for maintenance or cleaning. This results in far more reliable operation and easier handling of the air freshener.

[0026] It goes without saying that such a room fragrance device is not only suitable for fragranced rooms in the narrower sense, but also for deodorizing them, in particular by releasing odor-neutralizing substances.

[0027] Additionally, the evaporator can also be arranged on the interchangeable container and be replaceable along with it. This is particularly advantageous if the liquid containing the fragrance also contains non-volatile components that remain on the evaporator during operation of the room fragrance device. If, as in the aforementioned embodiment, the evaporator, together with the interchangeable container and the dosing unit, form a single, integrated interchangeable module, cleaning of any parts that come into contact with the liquid is unnecessary. This is particularly advantageous when changing the fragrance composition, as contamination of a second fragrance composition by a previously used first can be prevented. As a result, different fragrance compositions can be used with a single room fragrance device in relatively quick succession and, if desired, repeatedly, as needed.

[0028] The dosing device can include a drive unit that can be coupled to the dosing unit via coupling means, with the drive unit preferably being mounted in or on the room fragrance device. By separating the dosing unit and the drive unit, the potentially expensive and reusable drive unit can be designed as a fixed component of the room fragrance device. This increases the cost-efficiency of the device while maintaining a high level of reliability. The drive unit can be selected from a list consisting of a solenoid, a spindle drive, a wedge drive, a crank or cam drive, a servo motor, an actuator, and an actuating lever. These are components commonly used in appliance manufacturing that ensure reliable operation of the dosing unit.

[0029] The metering unit comprises a piston with a circumferential groove, the piston being slidably mounted in a cylinder such that the circumferential groove can be selectively brought into fluid contact with either the interior or exterior of the exchangeable container via a piston stroke. This represents a particularly simple and cost-effective design of the metering unit.

[0030] The dosing unit can be mounted on the bottom of the swap body. This has the advantage that the entire liquid contained in the swap body can be dosed by the dosing unit without requiring a separate supply line. For this purpose, the dosing unit can be at least partially integral with the bottom of the swap body. Preferably, the bottom of the swap body is designed as a separate part, while the lid of the swap body is formed integrally with it.

[0031] In the dosing unit design described above, the circumferential groove can be in fluid contact with the interior of the exchangeable container at the piston's top dead center and with its exterior at the piston's bottom dead center. Particularly in this design, but also in general, the piston can be displaced from its top dead center to its bottom dead center by the influence of gravity. Alternatively, the piston can be returned from a deflected position, especially from its top dead center, to its initial position, especially its bottom dead center, by means of a spring element. All of these variations allow for a simple design of the dosing unit, making it cost-effective to manufacture and ensuring reliable operation.

[0032] In a version of the dosing unit with a spring element, a damping element may also be present. This serves to prevent, or at least reduce, jerky or sudden movements of the piston. The damping element may comprise a piston arranged in a cylinder, around which and / or through which a liquid flows. This can be the same piston and cylinder used for dosing the liquid. The liquid in question is preferably the liquid containing the fragrance in the replaceable container. This has the advantage that once the liquid is used up, the damping effect is reduced or disappears entirely. This alerts the user, particularly through the altered and sometimes louder operating noises of the device, that the liquid has been used up.

[0033] The interchangeable module can be secured with a locking element, particularly before its initial use. In the interchangeable module design described above, the locking element is preferably a fork-shaped element that engages in a circumferential locking groove on the piston of the metering unit. The locking element prevents accidental activation of the metering unit by blocking the longitudinal movement of the piston in the cylinder.

[0034] Under normal operating conditions, the liquid can be drawn to the evaporator by the influence of gravity. This eliminates the need for additional pumps or conveying equipment.

[0035] The evaporation element can be designed in the form of a membrane, preferably stretched over a surrounding frame. Using a membrane has the advantage that, compared to its volume, it has a relatively large surface area that can be effectively brought into contact with the airflow. In particular, if evaporation occurs on both sides of the membrane, a high evaporation rate can be achieved.

[0036] When the room fragrance device is operated as intended, the membrane can be aligned horizontally and, in particular, parallel to the airflow generated by the fan. This ensures optimal airflow over the membrane by the airflow generated by the fan.

[0037] The membrane can be made of a textile, a plastic film, a non-woven fabric, or paper. These materials absorb the liquid to be evaporated, but still ensure the efficient release of its volatile components into the surrounding air.

[0038] The membrane can consist of a functional textile with a liquid-retaining side and a liquid-draining side. This can further improve the evaporation characteristics of the membrane.

[0039] In a room fragrance device with a drive and an evaporation element designed as a membrane, the dosing unit can be coupled to the drive by applying pressure to both sides of the membrane. A dosing unit mounted on one side of the membrane is driven by a coupling element mounted at least partially on the other side of the membrane, without requiring a penetration in the membrane. For this to work, the membrane must be flexible enough to allow the coupling element to lift and actuate the dosing unit.

[0040] The air outlet of the air duct can be directed vertically upwards during normal operation. This allows for optimal distribution of the scented air in a room.

[0041] The room fragrance device can include a holder for the replaceable container, the container preferably being insertable into the holder at only one angle. This ensures reliable and user-friendly coupling of the dosing unit with the drive. Furthermore, the holder ensures that the evaporation element, particularly the membrane, is always correctly aligned in the airflow.

[0042] When using the room fragrance dispenser as intended, the interchangeable container can be inserted into the holder vertically, from top to bottom. This has the advantage that the container does not need to be locked in place and remains there solely by gravity. With this design, the coupling of the dosing unit to the drive can be done in the opposite direction, vertically from bottom to top.

[0043] The room fragrance unit may include an air filter. The air filter may be attached to a filter frame positioned in front of the fan. The presence of an air filter is particularly advantageous when the room fragrance unit is placed directly on the floor of a room to be fragranced, where the dust concentration is comparatively high. The filter reduces contamination of the room fragrance unit by dust particles on the floor. It also essentially prevents the unit from stirring up dust. In certain cases, such a filtered unit can perform an air-purifying function in addition to its fragrance function. Preferably, the air filter is changed each time the fragrance container is replaced.

[0044] An unclaimed item refers to a replaceable container for a room fragrance device containing a liquid with a fragrance. A dosing unit is at least partially arranged in or on the replaceable container. Furthermore, an evaporation element may also be arranged on the replaceable container. The dosing unit can then be actuated to dispense the liquid onto the evaporation element by means of a drive mechanism associated with the room fragrance device.

[0045] The metering unit can include a piston with a circumferential groove. The piston is slidably mounted in a cylinder such that the circumferential groove can be brought into fluid contact with either the interior or exterior of the exchangeable container via a piston stroke.

[0046] The evaporation element can be designed in the form of a membrane. The membrane is preferably stretched over a surrounding frame.

[0047] The swap body can be equipped with means for pressure equalization with its environment. These means can be designed as a pressure equalization tube attached to the bottom of the swap body, as a bore running longitudinally along the piston of the dosing unit, as a bag, or as a pressure equalization membrane.

[0048] It goes without saying that the aforementioned individual features of the room fragrance device, which relate to the replaceable container, can also be present in the container on its own. Likewise, individual features of the room fragrance device are also particularly advantageous compared to the prior art, even independently of the replaceable container.

[0049] The room fragrance device according to the invention can be designed as a standalone device for independent operation or as a component of a ventilation system, in particular for connection to such a system.

[0050] An unclaimed item refers to a ventilation system comprising a room fragrance device as described above. The ventilation system may include at least one fresh air duct. The room fragrance device may be connected to the fresh air duct via a bypass. However, the room fragrance device itself may also form the bypass. It is also conceivable that the room fragrance device is located within the fresh air duct itself.

[0051] Further advantages and individual features of the invention will become apparent from the following description of an exemplary embodiment and from the drawings.

[0052] They show schematically: Figure 1 : Perspective exterior view of a room fragrance device according to the invention; Figure 2 : Illustration of a room fragrance device according to Figure 1 without the front cover; Figure 3 : Illustration of a room fragrance device according to Figure 2 ,additionally without inner cover; Figure 4 : Illustration of a room fragrance device according to Figure 3 , additionally without rear cover; Figure 5 Simplified perspective view of individual components of a room fragrance device according to Figure 1 in the arrangement intended for operation; Figure 6 Perspective view of an interchangeable module for a room fragrance device according to Figure 1 ; Figure 7 Detailed view of an interchangeable module according to Figure 6 with safety element; Figure 8 : Partially simplified perspective view of a group of individual components of a room fragrance device according to the invention; Figure 9 : Sectional view of the representation according to Figure 8 ; Figure 10 : Sectional view of the representation according to Figure 8 , wherein the group of individual components is in the actuated state; Figure 11 : Detailed view of the in Figure 9 recognizable dosing unit; Figures 12 to 15: Simplified representation of the principles of a dosing unit of a room fragrance device according to the invention; Figure 16 : Perspective sectional view of a room fragrance device according to Figure 1 ; Figure 17 : Air distribution in a room scented by a room scenting device according to the invention; Figures 18 to 21 : Simplified diagrams of the principles of pressure equalization in a replaceable container for a room fragrance device according to the invention in various versions; Figure 22 : A first possibility of integrating a room fragrance device according to the invention into a ventilation system; Figure 23 Enlarged partial section of a room fragrance device according to Figure 22 ; Figure 24 : A second possibility for integrating a room fragrance device according to the invention into a ventilation system.

[0053] Figure 1Figure 1 shows a perspective external view of a room fragrance device 1 according to the invention. The device 1 has an outer housing 21, which consists of a rear cover 22 and a front cover 23. The air inlet 3 is formed by an area with a plurality of holes in the front cover 23. The air outlet 4 is designed as a vertically upward-facing opening. As will be explained below, this orientation of the air outlet is of central importance for the distribution of the fragranced air in a room.

[0054] As from Figure 2As can be seen, the replaceable container 6 and the control unit 18 are located behind the front cover 23, which also extends over the top of the device 1. When the front cover is mounted on the device 1, the part of the front cover 23 that extends over the top of the device 1 can be removed to access the replaceable container 6 and the control unit 18. This makes both parts 6 and 18 easily accessible to the user, significantly increasing the ease of use of the device 1. The replaceable container 6 can thus be easily exchanged. Likewise, convenient operation of the control unit 18 is ensured. An inner cover 24 is located behind the front cover 23. The inner cover 24 has an area with slots 29 through which the air to be scented is drawn in.

[0055] In Figure 3The absence of the inner cover 24 reveals further details of the room fragrance device 1. The control unit 18 is now more clearly visible. Furthermore, the blower 5 is visible, which serves to convey air through the air duct 2 from the air inlet 3 to the air outlet 4. A filter frame 20 is mounted in front of the blower 5, into which an air filter 19 can be inserted, which is only partially shown in this illustration. The air filter 19 can be inserted into or removed from the filter frame 20 from the underside of the device 1 using the tab 38.

[0056] Figure 4 The room fragrance device 1 shows, according to the preceding Figures 1 to 3 completely without an outer casing 21.

[0057] Figure 5 shows essential individual components of the room fragrance device 1 according to the preceding Figures 1 to 4, partially simplified, in their relative arrangement as intended for the operation of the device. It can be seen that the blower 5 is oriented such that the airflow it generates passes along both sides of the membrane 8. In the embodiment shown, the exchangeable container 6, the dosing unit 7 (not visible here), and the membrane 8 form an interchangeable module 34. The drive 9 for the dosing unit 7 can be coupled to it via coupling means 10.

[0058] In Figure 6 The interchangeable module 34, consisting of interchangeable container 6, dosing unit 7 and membrane 8, can be seen individually. It can be seen that the membrane 8 is stretched over a circular, surrounding frame 16.

[0059] Figure 7Figure 1 shows an enlarged view of the lower area of ​​the interchangeable module 34, which is secured by a locking element 35. The locking element 35 shown is a fork-like element that engages in a circumferential locking groove 39 on the piston 11 of the metering unit 7. The locking element 35 prevents accidental activation of the metering unit 7 before the interchangeable module 34 is used for the first time.

[0060] As from the Figures 8 to 10 As can be seen, in the illustrated embodiment, the coupling of the metering unit 7 to the drive 9 is achieved directly via the coupling means 10 by applying pressure to both sides of the membrane 8. This membrane is not penetrated. The sectional views of the Figures 9 and 10 The arrangement of the dosing unit 7 on the bottom 15 of the interchangeable container 6 is also recognizable. Figure 9 The dosing unit 7 is shown in the un-displaced state, while Figure 10This shows the diaphragm in its deflected state. It can be seen that the diaphragm 8 is pushed upwards and temporarily stretched by actuating the dosing unit 7.

[0061] Out of Figure 11Details of the metering unit 7 are shown. This unit comprises a piston 11 with a circumferential groove 12, which is mounted to slide longitudinally in a cylinder 13. The upper part of the piston 11 extends into an additional cylinder 40. An annular element 41 is attached to the piston 11 and is firmly connected to it via an interference fit, but does not form a sealing seal with the additional cylinder 40. The flow of a liquid located in the additional cylinder 40 around the annular element 41 creates a damping effect during the stroke of the piston 11. A spring 36 is installed in the additional cylinder, which applies a preload force to the piston 11. The additional cylinder 40 has a connection 37 to the interior 14 of the exchangeable container 6. The retaining groove 39 is also visible in the lower part of the piston 11.

[0062] The Figures 12 to 15illustrate the operating principle of a dosing unit 7 of a room fragrance device according to the invention. 1. In the simplified representations shown, the exchangeable container 6 is filled with a liquid 25 containing a fragrance, which surrounds the dosing unit 7.

[0063] In Figure 12 The metering unit 7 is shown with the piston 11 at its bottom dead center. The circumferential groove 12 is in fluid communication with the outside of the exchangeable container. 6.

[0064] In Figure 13 The drive 9 exerts a lifting force on the piston 11 via the coupling means 10. This pushes the piston upwards.

[0065] Figure 14 Figure 7 shows the dosing unit 7 with the piston 11 at its top dead center. The circumferential groove 12 is now in fluid communication with the interior 14 of the exchangeable container. 6.Air located in the circumferential groove 12 is accordingly displaced by the liquid 25 and rises into the upper part of the exchangeable container, as indicated by the two arrows in the area of ​​the circumferential groove 12.

[0066] Figure 15 Figure 7 shows the metering unit after the piston 11 has returned to its starting position, namely to its bottom dead center. It can be seen that in the present embodiment this occurs automatically, i.e., solely through the influence of gravity on the piston 11. At the bottom dead center, the circumferential groove 12 is again in fluid communication with the outside of the exchangeable container 6, causing the liquid in the circumferential groove 12 to flow downwards, as indicated by the two arrows in the area of ​​the circumferential groove 12.

[0067] In Figure 16The air duct 2 of the room fragrance unit 1 is particularly clearly visible. It can be seen that the air to be fragranced is drawn in by the blower 5 through the front cover 23 and the inner cover 24, and then guided along both sides of the membrane 8 through the air duct 2. The fragranced air leaves the room fragrance unit 1 through the air outlet 4 in a vertical upward direction.

[0068] Figure 17Figure 1 shows the arrangement of a room fragrance device 1 in a room 26 to be fragranced, with a person 27 present in the room. A key aspect of the room fragrance system shown is that the device 1 is positioned near a wall 31. The air to be fragranced is drawn in horizontally from the floor area of ​​the room 26 and, after fragrance has been applied, is released vertically upwards along the wall 31 by the device 1. This creates a convection current 28 that spreads along the wall 31 and the ceiling 32. This allows for a particularly effective distribution of the fragranced air in the room 26, resulting in a particularly pleasant fragrance experience for the person 27.

[0069] The Figures 18 to 21Figure 1 shows various methods of pressure equalization in a replaceable container 6 for an inventive room fragrance device 1. While the design of the dosing unit 7 generally results in pressure equalization within the container 6 during normal operation of the device 1, additional equalization may still be necessary, particularly if the ambient pressure of the replaceable container 6 changes when it is not in use. This can occur, for example, during transport of the container 6 to a consumer, or when an inventive room fragrance device 1 is installed in a vehicle. Pressure fluctuations can be caused, in particular, by changes in altitude or temperature. Pressure fluctuations requiring pressure equalization in the replaceable container 6 can also occur when an inventive room fragrance device 1 is installed in a ventilation system.

[0070] As from Figure 18 As can be seen, pressure equalization can be achieved by means of a pressure equalization pipe 17 attached to the bottom 15 of the swap body 6. The pressure equalization pipe 17 establishes a fluid connection between the interior 14 of the swap body 6 and its surroundings (indicated by the double arrow). Due to the positioning and length of the pipe 17, escape of the liquid 25 present in the container 6 is essentially prevented, regardless of its orientation, as long as the container 6 is filled to a maximum of half its capacity. Should small quantities of liquid 25 nevertheless escape from the container 6, they generally reach the membrane 8 (not shown here), where they merely evaporate. Contamination of the surroundings is thus virtually impossible. Figure 19 shows one that corresponds to the one according to Figure 18related design in which pressure equalization takes place via a bore 30 extending in the longitudinal direction of the piston 11.

[0071] The Figure 20 Figure 1 shows an alternative embodiment of a pressure-equalizing container 6 according to the invention. Here, a bag 42 containing the liquid 25 is arranged in the interior 14 of the container 6. Pressure equalization to the environment is achieved via the pressure equalization opening 43 (indicated by the double arrow). When the bag 42 is emptied by the metering unit 7, it collapses. Figure 21 shows one that corresponds to the one according to Figure 20 related embodiment in which pressure equalization takes place via a pressure equalization membrane 44 installed in the interior 14 of the container 6.

[0072] The Figure 22Figure 1 shows a further embodiment of a room fragrance device 1 according to the invention, which is designed for installation in a ventilation system. This can be an existing ventilation system or a new installation – in a building or in a vehicle. The device 1 is generally connected as a bypass to an air-conducting element, in particular to a fresh air duct 45 (not shown here, see, however, [reference]). Fig. 24 ). In the example given, the device 1 has an air inlet 3 and two air outlets 4. The airflow introduced into the room fragrance unit 1 is accordingly split in two. For this purpose, air deflectors 46, 46' are attached, among other things. The room fragrance unit 1 shown is designed to be connected to a ventilation system via pipes or hoses.

[0073] As from Figure 23 As can be seen, the interchangeable module 34 of the room fragrance device 1 according to Figure 22Two dosing units 7, 7' are shown. The drives 9, 9' of the dosing units 7, 7' are also each present in duplicate. Furthermore, the pressure equalization pipe 17 attached to the bottom 15 of the swap body 6 is clearly visible.

[0074] The Figure 24 Figure 1 shows a further embodiment of a room fragrance device 1 according to the invention, which is designed for operation with a ventilation system. The device 1 is attached to a fresh air duct 45, through which an airflow runs in the longitudinal direction. The room fragrance device 1 is connected to the fresh air duct 45 via an air inlet 3 and two air outlets 4. During operation, air is drawn from the fresh air duct 45 by the blower 5, circulated, and then reintroduced into the fresh air duct 45.

Claims

1. A room fragrancing device (1) comprising an air duct (2) with an air inlet (3) and an air outlet (4), a fan (5) for conveying air through the air duct (2) from the air inlet (3) to the air outlet (4), a replaceable container (6) for a liquid containing a fragrance, a metering device for the liquid with a metering unit (7) and an evaporation body (8) arranged inside the air duct (2), wherein, to evaporate the liquid, it can be fed from the replaceable container (6) to the evaporation body (8) by means of the metering unit (7), wherein the metering unit (7) is arranged at least partially in or on the interchangeable container (6) and can be replaced together with the latter, characterised in that the metering unit (7) comprises a piston (11) having a circumferential groove (12), wherein the piston (11) is displaceably mounted in a cylinder (13) in such a way that the peripheral groove (12) can be brought into fluid communication with the interior (14) of the interchangeable container (6) or with the exterior of the interchangeable container (6) as desired over a piston stroke.

2. Room fragrancing device (1) according to claim 1, characterised in that the evaporation body (8) is also arranged on the interchangeable container (6) and can be replaced together with the latter.

3. Room fragrancing device (1) according to one of claims 1 or 2, characterised in that the metering device comprises a drive (9) which can be coupled to the metering unit (7) via coupling means (10) and that the drive (9) is preferably attached in or on the room fragrancing device (1).

4. Room fragrancing device (1) according to one of the claims 1 to 3, characterised in that the circumferential groove (12) is in fluid communication with the interior (14) of the interchangeable container (6) at the top dead centre of the piston (11) and with the exterior of the piston (11) at the bottom dead centre of the piston (11).

5. Room fragrancing device (1) according to one of the claims 1 to 4, characterised in that the piston (11) is displaceable from its upper dead centre to its lower dead centre under the influence of gravity.

6. Room fragrancing device (1) according to one of the claims 1 to 4, characterised in that the piston (11) can be returned from its upper dead centre to its lower dead centre via a spring element.

7. Room fragrancing device (1) according to one of the claims 1 to 6, characterised in that during proper operation the liquid can be guided to the evaporation body (8) under the influence of gravity.

8. Room fragrancing device (1) according to one of the claims 1 to 7, characterised in that the evaporation body (8) is configured in the form of a membrane which is preferably stretched on a surrounding frame (16).

9. Room fragrancing device (1) according to claim 8, characterised in that the membrane (8) is aligned horizontally and in particular parallel to the air flow generated by the blower (5) when the room fragrancing device (1) is operated as intended.

10. Room fragrancing device (1) according to claim 8 or 9, characterised in that the membrane (8) consists of a textile, a plastic film, a fleece or a paper.

11. Room fragrancing device (1) according to claim 8 or 9, characterised in that the membrane (8) consists of a functional textile with a liquid-storing side and a liquid-removing side.

12. Room fragrancing device (1) according to claim 1 and one of claims 8 to 11, characterised in that the metering unit (7) can be coupled to the drive (9) by acting on both sides of the membrane (8).

13. Room fragrancing device (1) according to one of the claims 1 to 12, characterised in that the air outlet (4) of the air duct (2) is directed upwards in a vertical direction when operated as intended.

14. Room fragrancing device (1) according to one of the claims 1 to 13, characterised in that the room fragrancing device (1) comprises a holder for the interchangeable container (6), wherein the interchangeable container (6) is preferably insertable into the holder in only one angular position.

15. Room fragrancing device (1) according to one of claims 1 to 14, characterised in that the room fragrancing device (1) comprises a control unit (18) for the metering device.