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 onrather than recessed withinthe wall. The dryer has a projecting part which projects outwardly either from the wall or from a rear part of the dryer, and the air-knife is directed downwardly onto the user's hand as it is passed lengthwise underneath the projecting part of the dryer. The air knife is discharged through one or more discharge apertures, and these discharge apertures are positioned towards the front of the projecting part so that they are spaced at least 75 mm from the wall or, as the case may be, 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, the hand dryer being configured to have a maximum depth, front-to-back, of 150 mm or less when it is surface-mounted onrather than recessed withina wall, the dryer having a projecting part which projects outwardly either from the wall or from a rear part of the dryer, the air-knife being directed downwardly onto the user's hand as it is passed lengthwise underneath the projecting part of the dryer, the air knife being discharged through one or more discharge apertures at a speed of at least 80 m/s, the one or more discharge apertures being positioned towards a front of the projecting part so that they are spaced at least 75 mm from the wall or the rear part of the dryer.

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

3. The hand dryer of claim 1 or 2, wherein the discharge apertures are spaced said maximum depth from the wall.

4. The hand dryer of claim 1, wherein the one or more discharge apertures are provided on an underside of the projecting part.

5. The hand dryer of claim 4, wherein the one or more discharge apertures are provided along a front lower edge of the projecting part.

6. The hand dryer of claim 1, wherein the projecting part is an external casing of the hand dryer.

7. The hand dryer of claim 6, the discharge apertures being arranged in a V-configuration viewed from the front of the dryer.

8. The hand dryer of claim 1, 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.

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

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

11. The hand dryer of claim 9 or 10, wherein the width of the slot, or the width of each air hole, is less than 2 mm.

12. The hand dryer of claim 9 or 10, wherein the length of the slot, or the combined length of the line of air holes, is at least 80 mm.

13. The hand dryer of claim 9 or 10, wherein the dryer comprises two such slots or lines of air holes for discharging two respective, separate air knives: one air knife for each hand.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

(2) FIGS. 1 and 2 are schematic perspective views of conventional air-knife hand dryers;

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

(4) FIG. 4 is a side view of the hand-dryer in FIG. 3;

(5) FIG. 5 are schematic views looking down on the hand dryer shown in FIG. 3, illustrating the mode of use of the hand dryer;

(6) FIG. 6 is a side view of the bottom part of the hand dryer of FIG. 3;

(7) FIG. 7 is a schematic perspective view of a wall-mountable hand dryer in accordance with a second embodiment of the present invention;

(8) FIG. 8 is a side view corresponding to FIG. 7;

(9) FIG. 9 is a schematic perspective view of a wall-mountable hand dryer in accordance with a third embodiment of the present invention;

(10) FIG. 10 is a side view corresponding to FIG. 9;

(11) FIG. 11 is a schematic perspective view of a wall-mountable hand dryer in accordance with a fourth embodiment of the present invention;

(12) FIG. 12 is a schematic perspective view of a wall-mountable hand dryer in accordance with a fifth embodiment of the present invention;

(13) FIG. 13 is a schematic perspective view of a wall-mountable hand dryer in accordance with a sixth embodiment of the present invention;

(14) FIG. 14 is a schematic perspective view of a wall-mountable hand dryer in accordance with a seventh embodiment of the present invention; and

(15) FIG. 15 is a side view corresponding to FIG. 14.

DETAILED DESCRIPTION OF THE INVENTION

(16) For simplicity, unless otherwise stated corresponding features have been given corresponding reference numerals in the following description.

(17) FIGS. 3 and 4 illustrate a wall-mountable hand dryer 1 which works by using an air knife 3a curtain or sheet of moving airto wipe the water from a user's hands.

(18) The hand dryer 1 is illustrated in its normal wall-mounted orientation.

(19) The hand dryer 1 comprises an external box-like casing 5 which projects a maximum depth X from the wall 7. In this case X=4 inches (101.6 mm) and thus the dryer is ADA-compliant, meaning that it complies with the Americans with Disabilities Act 1990:

(20) 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. . . .
Source: ADA Accesibility Guidelines for Buildings and Facilities (ADAAG)

(21) The air-knife 3 is discharged downwardly through a discharge aperture 9 on the underside of the casing 5.

(22) 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).

(23) The user dries the hands palm-open, one side at a time, moving the hand lengthwise front-to-back underneath the discharge slot 9. This is illustrated in FIG. 5, looking down on the dryer from above.

(24) The discharge slot 9 is 250 mm longintended to span both hands held side-by-side under the discharge slot. A shorter discharge slot may alternatively be usedsay, 120 mm in lengthto dry first one hand and then the other in turn.

(25) As the hands are moved relative to the discharge slot 9, the air-knife 3 mechanically wipes the water from the surface user's hands to dry them.

(26) 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 as it passes underneath the discharge slot 9, increasing the effective depth of the dryer (FIG. 6).

(27) If the discharge nozzles are spaced a distance, D, from the wall then the effective depth, d, is given by D=d cos . To provide for a comfortable pitch angle in most cases, D is set at 75 mm in accordance with the invention, so that the discharge slot 9 is spaced 75 mm from the wall 5 in use.

(28) The precise pitch angle 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 mmequating to a pitch angle of 60 degreeswhereas a user with small hands may only require an effective depth d of 120 mmequating to a pitch angle of approximately 50 degrees.

(29) If the maximum depth of the dryer exceeds 75 mm, then shallower pitch angles can be achieved by arranging the discharge apertures further towards the front of the dryer.

(30) 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.

(31) The discharge slot 9 is less than 2 mm in width. The motor-driven fan is configured to provide 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.

(32) Alternatively, a source of compressed air may be used to feed the discharge slot 9 via a plenum chamber behind the slot 9.

(33) The discharge slot 9 is formed directly in the wall of the casing 5. This provides for easy-cleaning of the casing 5, and allows the casing 9 itself to be used as a duct or plenum for feeding the discharge slot 9.

(34) Preferably, the slot 9 is machined into the wall of the casing 5this provides good dimensional tolerancebut if the casing 5 is moulded then the slot 9 itself could be moulded as part of the casing 5.

(35) FIG. 7 shows an arrangement in which the dryer 10 is provided with two separate discharge slots 12, 13one for each handrather than a single double-span discharge slot. Here, the slots are provided along a front lower edge of the casing (see FIG. 8), 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.

(36) In this arrangement, an effective depth of 150 mm equates to a pitch angle of 48 degrees and an effective depth of 120 mm equates to a pitch angle of 34 degrees.

(37) FIGS. 9 and 10 show an arrangement in which the dryer 100 is provided with discharge slots 15, 17 which are arranged in a V-configuration (viewed from the front of the dryer 100). This allows a user to bank the hands in use, making the drying action more comfortable for the user. The discharge slots 15, 17 are provided along a front, lower edge of the dryer 100, which edge is V-shaped to provide the required V-shaped configuration of the slots 15, 17.

(38) A guide ramp 19 is additionally provided behind the slots 15, 17 in this arrangement. This is not essential, but it provides the benefit that it encourages a user to pitch the hands down in use.

(39) The air-knife need not be directed vertically downwardly: it may project outwardly at an angle, for example. This is shown in FIG. 11. Here, a single discharge slot 70 is configured to discharge an air-knife 30 forwardly towards the user, at a downward angle. The dryer 1 is similar in other respects to the dryer 1.

(40) In the previous arrangements, the discharge apertures have been provided on the underside of an external casing of the dryer which projects from the wall. FIG. 12 shows an arrangement in which the discharge apertureagain in the form of a single discharge slot 9is provided on a projecting part 21 forming the roof of a drying cavity 23 for collecting the waste water. The projecting part 21 in this case projects out from the rear wall 25 of the drying cavity 23, which rear wall 25 forms a rear part of the dryer 110.

(41) The discharge slot 9 is spaced 75 mm from the rear wall 25 of the cavity 23.

(42) In general, if the discharge aperture faces a lower part of the dryerfor example the base 27 drying cavity 23 in dryer 110then the discharge aperture is preferably spaced a distance C from the lower part of the dryer to provide sufficient clearance under the discharge slot to allow the majority of users to pitch the hand down without touching the lower part of the dryer. In the arrangement in FIG. 12, this distance C is set at 120 mm, so that the discharge slot 9 is spaced 120 mm from the base 27 of the drying cavity 23.

(43) FIG. 13 shows an arrangement in which the discharge slot 9 is provided on a projecting part 29 which projects outwardly from a back-plate 31 forming a rear part of the dryer 1100. In this case the discharge slots face the floor, not a lower part of the hand dryer; this provides the benefit of a large clearance underneath the discharge aperture for pitching the hands in use.

(44) FIGS. 14 and 15 show a dryer 1000 which comprises discharge apertures in the form of a row of closely-spaced holes 700 formed in the wall of the casing 5.

(45) 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.

(46) The invention provides a relatively shallow hand dryer which nevertheless provides an effective air-knife drying action which is comfortable to use.