Field of the invention The present invention relates to a shower attachment.

Background of the invention

The shower attachment to which the present invention relates is an article that can either be mounted on a wall or be attached to the end of a flexible hose. At one end, the attachment has a coupling for connection to the water supply and at the other end it has a spray head from which the water stream emerges as a spray or as multiple jets.

In domestic applications, a powerful shower is highly desirable but consumes more water and is therefore wasteful of resources. For this reason, it has previously been proposed to incorporate in a shower attachment a device known as a fluidic amplifier or an ejector valve that aerates the water discharged from the spray head. An ejector valve has a through bore for the water flowing through the shower attachment. The through bore is of non-uniform cross section and at a point where it widens it is intersected by an air intake duct that opens into the ambient atmosphere. The water flow causes a drop in pressure which results in air being sucked in through the air intake duct to mix with the water stream. A water jet or spray augmented by the addition of air in this manner can reduce water consumption without detracting from the perceived power of the shower.

Object of the invention

The present invention seeks to provide an improved ejector valve design that provides better efficiency and reduced noise. Summary of the invention

According to the present invention, there is provided a shower attachment that includes an ejector valve to aerate the discharged water stream, wherein the ejector valve comprises a plurality of through bores arranged in parallel with one another to conduct the water flowing through the attachment, each of the through bores being connected to an air intake duct and being shaped to generate a reduced pressure at the intake duct in order to draw air into the water flowing through the attachment.

The ejector valve may conveniently be formed as a cylindrical body to be inserted into the shower attachment at its end remote from the shower head. Alternatively, it may be constructed as a cylindrical body mounted between the shower attachment and its water supply pipe or hose.

In either case, the air intake ducts of the separate through bores may be joined to one another within the cylindrical body, each of the ducts leading from a

respective through bore to a common single common opening in the outer surface of the cylindrical body. Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which :

Figure 1 is a sectional view of a shower handle invention with its parts separated,

Figure 2 is a section through an ejector valve insert for fitting into the coupling end of the shower handle of Figure 1,

Figure 3 is a perspective view of the ejector valve insert shown in Figure 2, Figures 4 is a sectional assembled view of the shower handle of Figure 1 after insertion of the ejector valve of Figure 2, and

Figure 5 is a sectional view of an alternative ejector valve having three through bores and intended to be retrofitted to an existing shower attachment by being mounted between the attachment and its supply pipe or hose . Detailed description of the preferred embodiment

A shower attachment embodying the invention is

assembled from four separate parts, namely a hollow elongate main body 10, a perforated plate 12 serving as the spray head, a fluidic amplifier or ejector valve insert 14, shown separately in Figure 2, and a small blanking plug 16 which hides a metallic screw 17 that holds the perforated plate 12 onto the body 10. All of these parts can be manufactured as plastics mouldings and may if desired be metal coated.

The hollow body 10 has a threaded coupling 18 at its end remote from the spray head to connect to the water supply, which may either be a fixed pipe in the case of a wall mounted shower or flexible hose in the case of the illustrated hand held shower attachment. A hole 20 is also formed in the body 10 near the threaded coupling 18.

The ejector valve insert 14 of Figures 2, 3 and 4 has two stepped axially extending bores 22, of which the

sections with the larger diameter open into the interior of the hollow body 10. Radial air intake ducts 24 intersect the larger section of axial bores 22 near the step where each bore widens. The transition need not in fact be stepped and the axial bore may be shaped as a Venturi . The two radial ducts may separately lead out to the atmosphere but to avoid the need for two holes, such as the hole 20 in Figure 1, in the shower handle, the two air intake ducts 24 can be joined to one another, to form a Siamese duct as shown in Figure 3. The section plane through the ejector valve insert 14 in Figure 4 is offset from the plane of symmetry of the insert 14 in order to pass through one of the two through bores 22.

The method of operation of a fluidic amplifier is well known and for the present context it suffices to understand that water flowing through the axial bores 22 will create a negative pressure at the inner end of the air intake ducts 24 and will therefore draw air into the water stream. Thus, the narrow diameter of the axial bore 22 reduces the flow rate of the water while the entrained air increases the bulk of the water stream, resulting in less water being used without any noticeable drop in the power of the shower.

The purpose of the hole 20 in the body of the handle 10 is to allow the radial ducts 24 of the fluidic amplifier insert 14 to communicate with the outside air and it is important to ensure correct alignment when the insert 14 is driven into the end of the body 10, as shown in Figure 2. To this end, interengaging formations provided on the insert 14 and on the body 10, such as a projection 28 on one to engage in a notch 30 in the other. Figures 2 to 4 also show that the insert 14 has an enlarged or flanged end to overlie the end of the coupling 18, thereby avoiding the need for a separate washer to establish a seal between the coupling 18 and the pipe to which it is connected.

The insert 14 is ideally a tight fit in the end of the hollow body 10 so that no air or water can pass between the insert 14 and the body 10. In practice, however, because of manufacturing tolerances, it may not be possible to achieve consistently a good water-tight fit between these two components and for this reason it is preferred to form grooves 32 and 34 on the exterior of the insert 14 to receive O-rings 36 and 38 to provide an effective seal both above and below the level of the hole 20 in the main body 10. In the orientation of the shower attachment shown in

Figures 1 and 2, any water remaining in the attachment at the end a period of use will flow towards the insert 14. In this case, the air intake ducts 24 and the hole 20 will act to allow trapped water to drain away without collecting in the hollow body 10. If the attachment is left tilted

counter-clockwise from this position, the water will run to the spray head and will drain through the perforated plate 12. By thus preventing stagnant water from collecting within the shower attachment in between periods of use, the

illustrated shower attachment reduces the risk of such water becoming contaminated with bacteria, such as legionella.

The main body 10 of the illustrated attachment needs to be specifically designed to receive the fluidic amplifier insert 14. In particular, it needs to have a cylindrical bore at one end, a hole 20 to communicate with the radial bore of the insert and a locating formation such as the notch 30. To avoid the need to modify the main body of the shower attachment, an alternative embodiment of the invention shown in Figure 5, is constructed as an adapter 114 designed to be retrofitted to an existing shower attachment. By fitting the adapter 114 between the existing shower attachment and its supply pipe or hose, it converts a conventional shower attachment to one that aerates the water stream.

The adapter 114 has female and male screw couplings 126, 128 at its opposite ends to enable it to be fitted between the supply pipe or hose and the shower attachment. Though the adapter may be constructed as a tubular casing for receiving an ejector valve insert, such as that shown in Figures 2 and 3, the adapter of Figure 5 itself acts as the ejector valve. In particular, it is formed with three through bores 122 each communicating with a respective air intake duct 124 leading to the ambient atmosphere. Only one of the three through bores 122 is seen in Figure 5 as the other two do not intersect the section plane of the drawing.