HAND DRYER

Abstract

The invention relates to a wall-mountable hand dryer of the type which uses an air-knife to wipe the water from a user's hand. In accordance with the invention, the hand dryer is configured to have a maximum depth, front-to-back, of less than 150 mm when it is surface-mounted on—not recessed within—the wall. The air-knife is discharged downwardly through one or more discharge apertures on the dryer. These discharge apertures are configured so that the air-knife is discharged in front of the wall or a rear part of the dryer, and is discharged forwards towards the user at a downward angle. The downward angle of the air-knife is such that the air-knife projects to a distance of at least 75 mm in front of the wall or, as the case may be, in front of the rear part of the dryer.

Claims

1. A wall-mountable air-knife hand dryer which uses an air-knife to wipe water from a user's hand, an external casing of the hand dryer being configured to have a maximum depth, front-to-back, of 150 mm or less when it is surface-mounted on—not recessed within—a wall, the air-knife being discharged downwardly through at least two discharge apertures on the casing at a speed of at least 80 m/s, the at least two discharge apertures being configured to discharge at least two separate air-knives, each air-knife being discharged in front of the wall or a rear part of the dryer forwards towards the user at a downward angle, the downward angle of the air-knife being such that the air-knife projects to a distance of at least 75 mm in front of the wall or in front of the rear part of the dryer.

2. (canceled)

3. The hand dryer of claim 1, wherein, in use, the discharge apertures are configured to discharge the air-knives in diverging directions: a first direction extending outwardly to the left of the dryer, and a second direction extending outwardly to the right of the dryer.

4. The hand dryer of claim 3, wherein the angle of divergence between the two air knives is at least 100 degrees.

5. The hand dryer of claim 1, the discharge apertures being arranged in a V-shaped configuration, viewed from the front of the dryer.

6. The hand dryer of claim 1, with the discharge apertures being spaced a minimum of 75 mm from the wall or the rear part of the dryer.

7. The hand dryer of claim 1, wherein the hand dryer is configured such that said maximum depth is 4 inches (101.6 mm) or less.

8. The hand dryer of claim 1, wherein the dryer has a projecting part which projects either from the wall or from a rear part of the dryer in use, the discharge apertures being provided on the underside of the projecting part.

9. The hand dryer of claim 8, wherein the discharge apertures face a lower part of the dryer, the discharge apertures being spaced at least 120 mm from said lower part of the dryer.

10. The hand dryer of claim 8, wherein the discharge apertures are provided on the underside of an external casing such that they face the floor when the dryer is surface-mounted on the wall.

11. (canceled)

12. The hand dryer of claim 1, wherein each air-knife is discharged through a single aperture in the form of an elongate slot.

13. The hand dryer of claim 1, wherein each air-knife is discharged through an elongate line of individual air holes.

14. The hand dryer of claim 12, wherein the width of the slot, or the width of each air hole, is less than 2 mm.

15. The hand dryer of claim 12, wherein the length of the slot, or the combined length of the line of air holes, is at least 80 mm.

16. The hand dryer of claim 12, wherein the dryer comprises two such slots or rows of air holes for discharging two respective, separate air knives: one air knife for each hand.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0027] FIGS. 1 and 2 are schematic perspective views of conventional air-knife hand dryers;

[0028] FIG. 3 is a schematic perspective view of a wall-mountable hand dryer in accordance with a first embodiment of the present invention;

[0029] FIG. 4 is a side view corresponding to FIG. 3;

[0030] FIG. 5 is a schematic view looking down on the hand dryer shown in FIG. 3, illustrating the mode of use of the hand dryer;

[0031] FIG. 6 is a side view of the bottom part of a wall-mountable hand dryer;

[0032] FIG. 7 is a schematic perspective of a wall mountable hand dryer in accordance with a second embodiment of the present invention;

[0033] FIG. 8 is a side view corresponding to FIG. 7;

[0034] FIG. 9 is a perspective view of a wall-mountable hand dryer in accordance with a third embodiment of the present invention;

[0035] FIG. 10 is a perspective view of a wall-mountable hand dryer in accordance with a fourth embodiment of the present invention;

[0036] FIG. 11 is a perspective view of a wall-mountable hand dryer in accordance with a fifth embodiment of the present invention;

[0037] FIG. 12 is a perspective view of a wall-mountable hand dryer in accordance with a sixth embodiment of the present invention;

[0038] FIG. 13 is a side view corresponding to FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

[0039] For simplicity, unless otherwise stated corresponding features have been given corresponding reference numerals in the following description.

[0040] FIGS. 3 and 4 illustrate a wall-mountable hand dryer 1 which works by using an air knife 3—a curtain or sheet of moving air—to wipe the water from a user's hands.

[0041] The hand dryer 1 is illustrated in its normal wall-mounted orientation.

[0042] The hand dryer 1 comprises an external box-like casing 5 which projects a distance X from the wall 7 (FIG. 4). The external casing 5 is configured so that X is 4 inches (101.6 mm). Thus, the dryer is “ADA-compliant”, meaning that it complies with the Americans with Disabilities Act 1990:

[0043] “4.4.1* General. Objects projecting from walls (for example, telephones) with their leading edges between 27 in and 80 in (685 mm and 2030 mm) above the finished floor shall protrude no more than 4 in (100 mm) into walks, halls, corridors, passageways, or aisles . . . . ”

[0044] Source: ADA Accesibility Guidelines for Buildings and Facilities (ADAAG)

[0045] The air-knife 3 is discharged downwardly at an angle α, through a discharge aperture 9 on the underside of the casing 5. The air knife 3 thus projects in front of the wall 7.

[0046] The discharge aperture 9 is in the form of an elongate discharge slot, which extends laterally across the dryer 1 (in this case generally parallel with the wall 7). The front and back walls of the discharge slot 9 are angled accordingly so that the air knife 3 is discharged at the required downward angle α.

[0047] The user dries the hands palm-open, moving the hand lengthwise front-to-back underneath the discharge slot 9. The hands are dried one-side at a time (cf. the conventional two-sided arrangements illustrated in FIGS. 1 and 2): one or more passes is made with the palms facing upwards, and then the hands are turned over and one or more passes is made with the back s of the hands facing upwards. This is illustrated in FIG. 5, looking down on the dryer 1 from above.

[0048] The discharge slot 9 is 250 mm long—intended to span both hands held side-by-side under the discharge slot. A shorter discharge slot may alternatively be used—say, 120 mm in length—to dry first one hand and then the other in turn.

[0049] As the hands are moved relative to the discharge slot 9, the air-knife 3 mechanically wipes the water from the surface of the user's hands to dry them.

[0050] The shallow depth of the dryer 1 on the wall 7 means that a typical user's fingertips will tend to contact the wall 7 if the hands are held horizontal underneath the dryer 1. However, the front-to-back drying action means that the user can avoid this by pitching the hand down at an angle θ as it passes underneath the discharge slot, increasing the effective depth of the dryer (FIG. 6).

[0051] If the air-knife projects out to a distance D in front of the wall, then the effective depth, d, is given by D=d cos θ. To provide for a comfortable pitch angle θ in most cases, the downward angle α of the air knife 3 is set so that D is 75 mm in accordance with the invention, meaning that the air knife projects (at some point) 75 mm in front of the wall 7.

[0052] The precise pitch angle θ will vary from user to user for a given value of D. A user with relatively large hands, may prefer an effective depth d of, say, 150 mm—equating to a pitch angle θ of 60 degrees if D=75 mm—whereas a user with small hands may only require an effective depth d of 120 mm—equating to a pitch angle θ of approximately 50 degrees if D=75 mm.

[0053] In the arrangement in FIGS. 3 and 4, the discharge slot 9 is spaced 50 mm in front of the wall 7. A shallower angle α may be used to provide a given value for D, by moving the discharge apertures further towards the front of the dryer. Positioning the discharge apertures a long a front edge of the dryer will minimize the angle α. Nevertheless, for a given position of the discharge apertures, discharging the air-knife forwards at a downward angle will maximize the distance D.

[0054] The discharge slot 9 is fed via a ducted motor-driven fan housed inside the external casing 5 of the dryer 1, which fan draws air in through the intakes 11 on the side of the casing 5 and forces this air out through the discharge slot 9 to generate the air-knife 3.

[0055] The discharge slot 9 is less than 2 mm in width. The motor-driven fan is configured to provide a an exit airspeed through the discharge slot 9 in excess of 80 m/s. This is intended to provide a well-defined, high speed, laminar air-knife which exhibits low wind shear. A particularly effective wiping action can be obtained at airspeeds in excess of 150 m/s.

[0056] Alternatively, a source of compressed air may be used to feed the discharge slot 9 via a plenum chamber behind the slot 9.

[0057] The discharge slot 9 is formed directly in the wall of the casing 5. Though not essential, this provides for easy-cleaning of the casing 5, and allows the casing 5 itself to be used as a duct or plenum for feeding the discharge slot 9.

[0058] Preferably, the slot 9 is machined into the wall of the casing 5—this provides good dimensional tolerance—but if the casing 5 is moulded then the slot 9 itself could be moulded as part of the casing 5.

[0059] FIG. 7 shows an alternative arrangement in which the air-knife 3 projects in front of a rear part of the hand dryer, rather than in front of the wall 7. The rear part—being a rear part in the sense that it is behind the air knife 3—is in this case the front face 13a of an external casing 13 of the hand dryer. FIG. 9 shows a different arrangement in which the rear part of the hand dryer is a back-plate 15 and the discharge slot is provided on the underside of a projecting part 25 of the dryer which projects from the back-plate 15 (cf. the arrangement in FIG. 3 where the discharge slot is likewise provided on a projecting part of the dryer—the external casing—but which projects instead from the wall 7). In each case, the respective downward angle α is such that the air knife 3 projects a distance of at least 75 mm in front of the rear part of the dryer (see FIG. 8, where D=75 mm).

[0060] The discharge aperture does not need to be an elongate slot. In the arrangement of FIG. 9, for example, the air knife 3 is discharged through a row of closely spaced discharge apertures in the form of round holes 17.

[0061] FIG. 10 shows an arrangement in which the discharge apertures are arranged facing a lower part of the dryer, rather than facing the floor. Here, the lower part of the dryer is a drip tray 23 for collecting waste water. The dryer is open to the sides in between the projecting part 25 and the drip tray 23, but this is not essential: side walls may be provided to define an enclosed drying cavity 27, as shown in FIG. 11. In this case, the projecting part 25 defines the roof of the cavity 27, and the discharge slot 9 faces the base 29 of the drying cavity 27.

[0062] In the arrangement in FIG. 10, the discharge apertures take the form of two separate discharge slots 19, 21—one for each hand—rather than a single “double-span” discharge slot.

[0063] In both of the arrangements of FIG. 9 and FIG. 10, the discharge slots 9, 19, 21 are provided along a front lower edge of the projecting part 25, so that they are spaced the maximum depth X from the wall, which in this case is 4 inches (101.6 mm) for ADA compliance. In this arrangement, an effective depth of 150 mm equates to a pitch angle θ of 48 degrees and an effective depth of 120 mm equates to a pitch angle θ of 34 degrees.

[0064] FIGS. 11 and 12 illustrate an arrangement in which the dryer is provided with discharge slots 29, 31 which are arranged in a V-configuration (viewed from the front of the dryer). This allows a user to bank the hands in use, making the drying action more comfortable for the user.

[0065] The discharge slots 29, 31 are provided along the front lower edge of the hand dryer, which edge is V-shaped to provide the required V-configuration for the slots 29, 31. The hand dryer has a maximum depth X of 4 inches (101.6 mm) when it is surface mounted on the wall.

[0066] The discharge slots 29, 31 are arranged so that the respective air knives diverge at an angle β. This helps direct the air knives either side of the user (who will be standing directly in front of the dryer in normal use). A preferred range for β is 100-120 degrees.

[0067] A guide ramp 33 is additionally provided behind the slots 29, 31s in this arrangement. This is not essential, but provides the benefit that it encourages a user to pitch the hands downwards underneath the discharge aperture(s) in use.

[0068] ADA compliance is not an essential part of the invention. The depth X of the dryer may be up to 150 mm when it is surface mounted on the wall: this is still a significantly shallower profile than the conventional air-knife hand dryers illustrated in FIGS. 1 and 2.