Variable air amplifier

Abstract

The invention provides a variable air amplifier for use in an airflow generating appliance. The variable air amplifier comprises a body comprising a through-hole defining an airflow channel having upstream and downstream ends. The body comprises a movable portion adapted to move between first and second positions, wherein the movable portion defines at least part of a first outlet, to discharge fluid from a downstream region of the body and away from the body, and a second fluid outlet, to discharge fluid through the through-hole from an upstream region of the body such that the discharged fluid entrains ambient fluid. The body further comprises an actuator adapted to the moveable portion between first and second positions wherein, when in the first position, the first outlet is open and the second outlet is closed, and when in the second position, the second outlet is open and the first outlet is closed.

Description

[0001] Variable Air Amplifier

[0002] BACKGROUND

[0003] There exist many applications for a controllable air flow, such as hair dryers or fans.

[0004] In many conventional airflow generating appliances, the appliance is provided with a single means of delivering the flow of air to the target. In order to change the shape of the airflow leaving the appliance, additional attachments are often required. This can be expensive, confusing and the attachments can take up a significant amount of space.

[0005] Further, in many conventional airflow generating appliances, in order to increase the delivery of air to the target the airflow generator, which may be a motorized fan, is simply driven harder. This has an upper limit and, particularly in smaller handheld devices, the upper limit may be insufficient for achieving the desired outcome.

[0006] There exist examples of airflow generating appliances that utilize air entrainment in order to amplify the airflow output by the appliances. However, this often results in a more diffused air output, which is not suitable for all applications. Once again, in such cases, the appliances are provided with only a single means of delivering the flow of air to the target.

[0007] SUMMARY

[0008] According to a first aspect of the invention, there is provided a variable air amplifier for use with an airflow generating appliance, the variable air amplifier comprising: a body comprising a central through-hole defining an airflow channel, the through- hole having an upstream end and a downstream end, the body comprising: a movable portion adapted to move between a first position and a second position, wherein the movable portion defines at least part of a first fluid outlet, to discharge fluid from a downstream end region of the body and away from the body, and a second fluid outlet, to discharge fluid from an upstream end region of the body and through the through-hole such that the discharged fluid entrains ambient fluid in the through-hole to generate amplified discharged fluid; and an actuator adapted to cause the moveable portion to move between the first position and the second position, wherein, when the moveable portion is in the first position, the first fluid outlet is open and the second fluid outlet is closed, and wherein, when the movable portion is in the second position, the second fluid outlet is open and the first fluid outlet is closed.

[0009] The invention provides a means of selectively adjusting an amount of air amplification applied to a flow of air generated by an airflow generating appliance. By actuating the movable portion to selectively open or close the first and second fluid outlets, the variable air amplifier may be configured to output a flow of air with minimal air entrainment or with maximal air entrainment according to the desired output.

[0010] Put another way, the invention provides a means of switching between a standard fluid flow output and an amplified fluid flow output by selectively opening and closing different fluid outlets positioned at different areas of the variable air amplifier body in order to cause different amount of entrainment of the ambient air.

[0011] In other words, the invention provides a means of switching between an amplified and an unamplified flow mode by switching between a fluid outlet that encourages air entrainment through the variable air amplifier body and a fluid outlet that does not encourage air entrainment though the variable air amplifier body.

[0012] The variable air amplifier described herein may be used as part of, or in conjunction with, any suitable airflow generating device. For example, the variable air amplifier may be attached to, or integrated with, a hair styling or hair drying device. Further, the variable air amplifier may be used with a fan, an air purifier, a dehumidifier and the like.

[0013] In the case where the variable air amplifier is attached to, or integrated with, a hair styling or hair drying device, the variable air amplifier may discharge a heated air flow. When the heated air is discharged from either the first fluid outlet or the second fluid outlet, the same amount of heat energy will be delivered to the user’s hair. However, the air entrainment when the fluid is discharged from the second fluid outlet will result in a higher volumetric flowrate when the second fluid outlet is open and the first fluid outlet is closed. Accordingly, the higher volumetric flowrate, and air mixing of the atmospheric air with the heated air, will lead to a cooler airflow for the user whilst still maintaining a similar dry time to the fluid discharged from the first fluid outlet. The moveable portion defines at least part of the first and second fluid outlets. For example, the first and second fluid outlets may be defined by a combination of the moveable portion and one or more of the body; and the actuator.

[0014] The actuator may be any suitable actuation arrangement for moving the moveable portion between the first and second positions. For example, the actuator may comprise one or more of a lever arrangement; a gearing arrangement; a sliding arrangement; a rotational arrangement; a pin and channel arrangement; and the like. For example, the actuator may be a rotatable element. The actuator may be adapted to cause the moveable portion to move relative the body in order to travel between the first and second positions.

[0015] When the movable portion is between the first position and the second position, the first fluid outlet and the second fluid outlet may partially open. The movement of the moveable portion between the first position and the second position may be continuous such that opening and closing of the first and second fluid outlets is continuously variable. In this way, the amount of air entrainment caused by the variable air amplifier may be continuously variable based on the proportion of fluid being discharged from the second fluid outlet compared to the amount of fluid being discharged from the first fluid outlet. The more open the second fluid outlet is, and correspondingly the less open the first fluid outlet is, the greater the level of air entrainment achieved by the variable air amplifier will be. Similarly, the more closed the second fluid outlet is, and correspondingly the more open the first fluid outlet is, the lower the level of air entrainment achieved by the variable air amplifier will be. Thus, the user may have full control of the air amplification across the range of minimal air entrainment to maximal air entrainment depending on the desired fluid output.

[0016] The direction of fluid flow from the first fluid outlet may be substantially the same as the direction of fluid flow from the second fluid outlet. In other words, the variable air amplifier may have a defined output direction, which may be referred to as being output from the front of the variable air amplifier. In the example where the airflow generating appliance is a hair dryer or hair styler, the output direction may be intended for being directed towards a user’ s hair.

[0017] The second fluid outlet may be arranged to direct a fluid flow over a surface of the body defining the central through-hole. The surface of the central through-hole may be inwardly curved. In this way, the fluid discharged from the second fluid outlet will mainly flow over the surface of the central though-hole and not in the central cavity of the central through-hole. This flow over the surface of the central through-hole causes an area of low pressure to form at the upstream end of the central through-hole, which entrains air from the atmosphere into the main flow path of the variable air amplifier.

[0018] The body may take any suitable shape with a through-hole defining an airflow channel therethrough.

[0019] For example, the body may be an annular cylinder. In this case, the central through- hole may be cylindrical, defining a bore of the annular cylinder. However, the central through-hole may take a different shape to the body.

[0020] In the case where the body is cylindrical, the first fluid outlet and the second fluid outlet may be annular. The first fluid outlet may be shaped to direct fluid towards a longitudinal axis of the annular cylinder so as to generate a converging fluid flow. In this way, the first fluid outlet may produce a focused, or jet-like, flow profile. The second fluid outlet may be arranged to direct a fluid flow over an inwardly curved surface of the body that defines the central through-hole, so as to generate a diverging fluid flow. In this way, the second fluid outlet may produce a diffused flow profile.

[0021] For instance, by virtue of the shape of the inwardly curved surface it naturally flares outwards at or near the downstream end. When airflow is directed over this surface, the Coanda effect causes a diverging fluid flow because the airflow adheres to the surface until it exits the variable air amplifier. The flaring of the downstream end of the inwardly curved surface therefore encourages the discharged fluid to diverge from the longitudinal axis of the body.

[0022] Further, in the case where the body is cylindrical, the actuator may be a cylindrical rotatable element. The actuator may have a diameter similar to that of the body. The actuator may be coupled to the movable portion by way of a pin and channel arrangement to translate the rotational movement of the actuator into longitudinal movement of the moveable portion between the first and second positions. The channel may be arranged in a helical shape on the actuator and the pin may be provided on the movable portion, or vice versa. The actuator may comprise a plurality of channels to receive a plurality of corresponding pins. The actuator may be fixed to the body, such that they move together, or may be coupled to the body such that the actuator and the body may move independently of each other. In an example, the actuator may be rotated in a clockwise manner in order to cause the moveable portion to move to the first position, opening the first fluid outlet and closing the second fluid outlet. The actuator may then be rotated in an anti-clockwise manner in order to move the movable portion to the second position, opening the second fluid outlet and closing the first fluid outlet. The actuator may be rotatable through a 45° angle or greater. The movable portion may be moveable across a range of 1.5mm or more.

[0023] According to second aspect of the invention, there is provided a haircare appliance having a variable air amplifier as described above.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 shows a variable air amplifier according to an aspect of the invention;

[0026] Figure 2 shows a variable air amplifier according to an aspect of the invention in a first mode of operation;

[0027] Figure 3 shows a variable air amplifier according to an aspect of the invention in a second mode of operation;

[0028] Figure 4A shows a schematic cross-section of a variable air amplifier according to an aspect of the invention in a first mode of operation;

[0029] Figure 4B shows a schematic cross-section of a variable air amplifier according to an aspect of the invention in a second mode of operation;

[0030] Figure 5 shows a cross-section of a variable air amplifier according to an aspect of the invention in a first mode of operation;

[0031] Figure 6 shows a cross-section of a variable air amplifier according to an aspect of the invention in an intermediate mode of operation; and

[0032] Figure 7 shows a cross-section of a variable air amplifier according to an aspect of the invention in a second mode of operation.

[0033] DETAILED DESCRIPTION

[0034] In the examples described below, the variable air amplifier is described in the context of a hair drying, or hair styling, device. However, the variable air amplifier described herein may be applied to any device capable of generating an airflow, such as a fan, an air filtration unit, a dehumidifier and the like. Figure 1 shows a variable air amplifier 100 for use in an airflow generating appliance according to an aspect of the invention.

[0035] The body 110 comprises a central through-hole 120 defining an airflow 130 channel, the through-hole having an upstream end 140 and a downstream end 150. In the example shown in Figure 1, the inner surface of the central through-hole is defined by the moveable portion 160. The moveable portion is described in further detail below with respect to Figures 5 to 7.

[0036] In the example shown in Figure 1, the body 110 is an annular cylinder. The central through-hole 120 is cylindrical, defining a bore of the annular cylinder. The central through-hole in Figure 1 is shown as being centred on the longitudinal axis of the annular cylinder of the body; however, the through-hole may be offset from the longitudinal axis in some examples.

[0037] In addition, Figure 1 shows an example mounting portion 115 between the variable air amplifier 100 and an airflow generating device.

[0038] In particular, Figure 1 shows the variable air amplifier 100 in the form of an attachment for mounting to an airflow generating device that is configured to supply a flow of fluid (in this case, air) to the variable air amplifier 100. The airflow generating device houses an air mover (in the form of a fan) that moves air from a device inlet to a device outlet (not shown). The device outlet is surrounded by a device mounting portion of the device which allows mounting of the variable air amplifier thereto. Alternatively, the variable air amplifier may be integrally formed with the airflow generating device.

[0039] To allow mounting of the variable air amplifier 100 to the device (which is held by a user in use), the variable air amplifier may comprise a mounting portion 115 that includes circumferentially spaced lugs 116 (that engage with corresponding features of the device 115). The variable air amplifier also includes a fluid inlet for receipt of fluid (i.e., an airflow) from the device when mounted thereto. An internal passage extends from the inlet into the interior of the variable air amplifier to permit the flow of fluid for discharge form the first and second fluid outlets.

[0040] Figure 2 shows the variable air amplifier 100 of Figure 1 in a first mode of operation.

[0041] In the example shown in Figure 2, the moveable portion 160 is at a first position, such that a first fluid outlet 170 is open to discharge fluid 180 from the body 110 from a downstream end region of the body and away from the body. When the moveable portion is in this first position, the second fluid outlet (not shown) is closed.

[0042] As shown in Figure 2, the first fluid outlet 170 is an annulus that is defined in part by the moveable portion 160. The first fluid outlet shown in Figure 2 is also defined in part by the body 110, and in particular the downstream end 150 of the body.

[0043] Figure 3 shows the variable air amplifier 100 of Figure 1 in a second mode of operation.

[0044] In the example shown in Figure 3, the moveable portion 160 is at a second position, such that a second fluid outlet 190 is open to discharge fluid 200 from the body 110 from an upstream end region of the body. When the moveable portion is in this second position, the first fluid outlet (not shown) is closed.

[0045] As shown in Figure 3, the second fluid outlet 190 is an annulus that is defined in part by the moveable portion 160. The second fluid outlet shown in Figure 3 is also defined in part by the body 110, and in particular the upstream end 140 of the body.

[0046] The second fluid outlet 190 shown in Figure 3 is arranged to direct the discharged fluid 200, or fluid flow, over a surface of the body 110 defining the central through-hole. In particular, the second fluid outlet is arranged to direct the discharged fluid over the inner surface of the moveable portion 160, which defines the central through-hole of the body. The surface of the central through-hole, i.e., the surface of the moveable portion, may be inwardly curved. Therefore, the surface of the central through-hole may act as an aerofoil to the discharged fluid 200.

[0047] As the fluid 200 is discharged from the second fluid outlet 190 and flows over the surface of the central though-hole from the upstream end 140 of the body 110 towards the downstream end 150, the ambient air within the central through-hole is dragged in the flow direction by friction with the discharged fluid flow. This creates an area of low pressure towards the upstream end of the central through-hole of the body, which will cause atmospheric air to move into this area and then flow through the central through-hole of the body as it meets the fluid discharged from the second fluid outlet. This generates an entrained fluid flow 210. This entrainment of the ambient air around the downstream end of the body amplifies the flow of fluid leaving the downstream end of the central through- hole. The amplified fluid flow is a combination of the discharged fluid 200 and the entrained fluid flow. It should be noted that a similar effect does occur when fluid is discharged from the first fluid outlet. However, compared to the entrainment achieved by discharging fluid form the second fluid outlet, the entrainment of ambient air by fluid discharge from the first fluid outlet is negligible.

[0048] By moving the movable portion 160 between the first position as shown in Figure 2 and the second position as shown in Figure 3, the first fluid outlet 170 or the second fluid outlet 190 may be opened, and the other fluid outlet closed, in order to switch the variable air amplifier 100 between different modes of operation.

[0049] Figures 4A and 4B show schematic representations of cross-sections of the variable air amplifier 100 in the first and second modes of operation, respectively. The variable air amplifiers of Figures 4A and 4B are identical to those shown in Figures 1 to 3 and common features are labelled with the same reference numerals. As shown in Figures 4A and 4B the direction of fluid flow from the first fluid outlet is substantially the same as a direction of fluid flow from the second fluid outlet.

[0050] Figure 4A shows a cross-section of the variable air amplifier 100 in a first mode of operation where the movable portion 160 is in a first position, such that a first fluid outlet 170 is open to discharge fluid 180 from the body 110 from a downstream end region of the body and away from the body. When the moveable portion is in this first position, the second fluid outlet (not shown) is closed.

[0051] In the example shown in Figure 4A, the first fluid outlet 170 is arranged to direct fluid 180 towards a longitudinal axis 220 of the annular cylinder of the body 110 so as to generate a converging fluid flow 225. The converging fluid flow results in a focused jet of fluid discharged from the variable air amplifier, which may be used for applying the fluid flow to a specific target area.

[0052] A small amount of air entrainment will occur in this operation mode leading to a negligible entrainment flow 230.

[0053] Figure 4B shows a cross-section of the variable air amplifier 100 in a second mode of operation where the movable portion 160 is in a second position, such that a second fluid outlet 190 is open to discharge fluid 200 from the body 110 from an upstream end region of the body and over a surface of the central through-hole. When the moveable portion is in this second position, the first fluid outlet (not shown) is closed. In the example shown in Figure 4B, the second fluid outlet 190 is arranged to direct the discharged fluid 200, or fluid flow, over a surface of the body 110 defining the central through-hole. In particular, the second fluid outlet is arranged to direct the discharged fluid over the inner surface of the moveable portion 160, which defines the central through-hole of the body. The surface of the central through-hole, i.e., the surface of the moveable portion, may be inwardly curved. Therefore, the surface of the central through-hole may act as an aerofoil to the discharged fluid 200.

[0054] As the fluid 200 is discharged from the second fluid outlet 190 and flows over the surface of the central though-hole from the upstream end 140 of the body 110 towards the downstream end 150, the ambient air within the central through-hole is dragged in the flow direction by friction with the discharged fluid flow. This creates an area of low pressure towards the upstream end of the central through-hole of the body, which will cause atmospheric air to move into this area and then flow through the central through-hole of the body as it meets the fluid discharged from the second fluid outlet. This generates an entrained fluid flow 210. This entrainment of the ambient air around the downstream end of the body amplifies the flow of fluid leaving the downstream end of the central through- hole. The amplified fluid flow 240 is a combination of the discharged fluid 200 and the entrained fluid flow.

[0055] In the example shown in Figure 4B, the fluid 200 discharged from the second fluid outlet 190 is discharged over an inwardly curved surface of the body, and in particular the movable portion, that defines the central through-hole so as to generate a diverging fluid flow 250.

[0056] Figures 5 to 7 show a cross-section of a variable air amplifier 100 in various modes of operation. Features in common with those shown in previous Figures are labelled with the same reference numerals.

[0057] In the example shown in Figure 5, the movable portion 160 is in the first position where the first fluid outlet 170 is open and the second fluid outlet 190 is closed.

[0058] Further, Figure 5 shows an actuator 260 adapted to cause the moveable portion 160 to move between the first position and the second position. The actuator shown in Figure 5 is a cylindrical rotatable element that is concentric with the cylindrical body 110. The actuator 260 is coupled to the movable portion 160 by way of a pin 280 and channel 270 arrangement to translate rotational movement of the actuator into longitudinal movement of the moveable portion between the first and second positions. The channel is arranged in a helical shape about the circumference of the body.

[0059] Fluid 180 is discharged from the first fluid outlet 170 and away from the body 110. Figure 5 shows an example of how the first fluid outlet may be arranged to direct fluid 180 towards a longitudinal axis of the annular cylinder of the body 110 so as to generate the converging fluid flow shown in Figure 4A.

[0060] In the example shown in Figure 6, the movable portion 160 is in between the first position and the second position where the first fluid outlet 170 and the second fluid outlet 190 are both partially open.

[0061] The movement of the moveable portion 160 between the first position and the second position is continuous such that opening and closing of the first 170 and second 190 fluid outlets is continuously variable. In the particular example shown in Figures 5 to 7, the movement of the moveable portion 160 between the first position and the second position is directly linked to the rotation of the actuator. As the rotation of the actuator is a means of continuous, i.e., not discrete, input, the movement of the moveable may be finely controlled by the user.

[0062] As both the first fluid outlet 170 and the second fluid outlet 190 are partially open, a portion of the fluid 180 discharged by the variable air amplifier will be discharged from the first fluid outlet in the converging flow profile discussed above with refence to Figure 4A. The remaining portion of the fluid 200 discharged by the variable air amplifier will be discharged from the second fluid outlet, thereby generating a partial entrained air flow 210. The net volume of fluid discharged from the partially open first and second fluid outlets will be the same as the volume of fluid discharged from one fully open fluid outlet. However, the addition of the partial entrained air flow will result in a partially amplified fluid output, which results in a greater volumetric flow rate than the operation mode shown in Figure 5, which provides no or negligible air entrainment, and a lower volumetric flow rate that the operation mode shown in Figure 7, which provides full air entrainment.

[0063] In the example shown in Figure 7, the movable portion 160 is in the second position where the first fluid outlet 170 is closed and the second fluid outlet 190 is open.

[0064] Fluid 200 is discharged from the second fluid outlet 190 over a surface of the moveable portion 160, which is inwardly curved. Figure 7 shows an example of how the second fluid outlet may be arranged to direct fluid 200 over the inner surface of the central through-hole, i.e., the inwardly curved surface of the movable portion, so as to generate the diverging fluid flow shown in Figure 4B.

[0065] As the fluid 200 is discharged from the second fluid outlet 190 and flows over the surface of the moveable portion 160, ambient air is entrained to generate an entrained air flow 210 as described above.

[0066] In use, the variable air amplifier 100 may begin in the state shown in Figure 5, with the first fluid outlet 170 open and the second fluid outlet 190 closed. The user may use the airflow generating device with the variable air amplifier 100 in this state whilst they require a focused flow profile.

[0067] When the user desires a partially amplified air flow, they partially rotate the actuator (for example by an angle of 20° - 30°) in order to move the moveable in a longitudinal direction (for example towards the front of the device that faces the user) to partially open the second fluid outlet, and partially close the first fluid outlet.

[0068] When the user desires a fully amplified air flow, they rotate the actuator (for example by an angle of 45° relative to the starting position) in order to move the moveable in a longitudinal direction (for example towards the front of the device that faces the user) to open the second fluid outlet and close the first fluid outlet.

[0069] Should the user desire a less amplified, or more focused, fluid flow they may simply rotate the actuator in the opposite direction in order to move the moveable in a longitudinal direction (for example towards the back of the device that faces away from the user) to open the first fluid outlet and close the second fluid outlet.

Claims

CLAIMS1. A variable air amplifier for use with an airflow generating appliance, the variable air amplifier comprising: a body comprising a central through-hole defining an airflow channel, the through- hole having an upstream end and a downstream end, the body comprising: a movable portion adapted to move between a first position and a second position, wherein the movable portion defines at least part of a first fluid outlet, to discharge fluid from a downstream end region of the body and away from the body, and a second fluid outlet, to discharge fluid from an upstream end region of the body and through the through-hole such that the discharged fluid entrains ambient fluid in the through-hole to generate amplified discharged fluid; and an actuator adapted to cause the moveable portion to move between the first position and the second position, wherein, when the moveable portion is in the first position, the first fluid outlet is open and the second fluid outlet is closed, and wherein, when the movable portion is in the second position, the second fluid outlet is open and the first fluid outlet is closed.

2. The variable air amplifier claimed in claim 1, wherein, when the movable portion is between the first position and the second position, the first fluid outlet and the second fluid outlet are partially open.

3. The variable air amplifier claimed in claim 2, wherein the movement of the moveable portion between the first position and the second position is continuous such that opening and closing of the first and second fluid outlets is continuously variable.

4. The variable air amplifier claimed in any of claims 1 to 3, wherein a direction of fluid flow from the first fluid outlet is substantially the same as a direction of fluid flow from the second fluid outlet.

5. The variable air amplifier claimed in any of claims 1 to 4, wherein the second fluid outlet is arranged to direct the discharged fluid over a surface of the body defining the central through-hole.

6. The variable air amplifier claimed in claim 5, wherein the surface of the central through-hole is inwardly curved.

7. The variable air amplifier claimed in any preceding claim, wherein the actuator is a rotatable element.

8. The variable air amplifier claimed in any preceding claim, wherein the body is an annular cylinder, and wherein the central through-hole is cylindrical, defining a bore of the annular cylinder.

9. The variable air amplifier claimed in claim 8, wherein the first fluid outlet is an annulus.

10. The variable air amplifier claimed in claim 9, wherein the first fluid outlet is shaped to direct fluid towards a longitudinal axis of the annular cylinder so as to generate a converging fluid flow.

11. The variable air amplifier claimed in any of claims 8 to 10, wherein the second fluid outlet is an annulus.

12. The variable air amplifier claimed in claim 11, wherein the wherein the second fluid outlet is arranged to direct a fluid flow over an inwardly curved surface of the body that defines the central through-hole, so as to generate a diverging fluid flow.

13. The variable air amplifier claimed in any of claims 8 to 12, wherein the actuator is a rotatable element, and wherein the actuator is cylindrical.

14. The variable air amplifier claimed in claim 13, wherein the actuator is coupled to the movable portion by way of a pin and channel arrangement to translate rotational movement of the actuator into longitudinal movement of the moveable portion between the first and second positions.

15. The variable air amplifier claimed in claim 14, wherein the channel is arranged in a helical shape.

16. A haircare appliance having a variable air amplifier according to any of claims 1 to 15.

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