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 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 (described in more detail below) that aerates the water discharged from the spray head. A jet or spray augmented in this way by the addition of air can reduce water consumption without detracting from the perceived power of the shower.

Hitherto, shower attachments incorporating such water saving devices have had the problem that water may collect within them after the water supply has been turned off. In certain environments, this presents a health hazard in that it can be a cause of spreading of legionella bacteria.

Object of the invention

The present invention seeks therefore to provide a shower attachment that offers the advantage of reduced water consumption while ensuring full drainage of the attachment at the end of each use. Summary of the invention

According to the present invention, there is provided a shower attachment comprising a hollow body having a coupling at one end for connection to a water supply and a spray head at the opposite end, characterised in that a fluidic amplifier is located at the coupling end of the body, the fluidic amplifier having an axially extending bore which is not uniformly cylindrical and through which water flows from the water supply to the spray head, and a radially extending bore which at one end communicates with the axially extending bore at a region where the diameter of the latter bore increases and at its other end communicates with the ambient air, the radially extending bore serving to introduce air into the water flowing through the shower attachment when the attachment is in use and serving to allow water to drain from the shower attachment when the attachment is not in use.

Because of the location of the fluidic amplifier at the opposite end of the attachment from the spray head, regardless of the attitude of the attachment when it is not in use, water remaining within it will either flow to the spray head or back towards the fluidic amplifier. Water at the spray head end will drain out through the jets of the spray head while water at the fluidic amplifier will drain through the radial bore through which air is drawn when the shower is in use.

In the preferred embodiment of the invention, the fluidic amplifier comprises a cylindrical insert which is formed with the axial and radial bores and which is inserted into the coupling for the water supply and a hole is formed in the body of the attachment to align with the radial bore of the insert. Interengaging formations are preferably provided on the insert and the hollow body to ensure that the insert is always in the correct orientation for proper alignment.

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 of a shower attachment of the invention with its parts separated,

Figure 2 is a section through the shower attachment of Figure 1 in its assembled state, and

Figure 3 is a perspective view of the fluidic amplifier insert shown in Figures 1 and 2.

Detailed description of the preferred embodiment

The shower attachment of 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 insert 14 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 fluidic amplifier insert 14 has a stepped axially extending bore of which the section with the larger diameter opens into the interior of the hollow body 10. A radial bore 24 intersects the larger section of axial bore 22 near the step where the bore widens. The transition need not in fact be stepped and the axial bore may be shaped as a Venturi.

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 bore 22 will create a negative pressure at the inner end of the radial bore 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 bore 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.

The drawings 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 radial bore 24 and the hole 20 will act to allow trapped water to drain away without collecting in the hollow body 10. If the attachment were left tilted counter- clockwise from this position, the water would run to the spray head and would drain through the perforated plate 12. By thus preventing stagnant water from collecting within the shower attachment in between periods of use, the invention 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. It is however alternatively possible to implement the invention as a retrofit to an existing shower attachment by providing an adapter that converts a conventional shower attachment to one that aerates the water stream. The adapter would have male and female screw couplings at its opposite ends to enable it to be fitted between the supply pipe or hose and the shower attachment. In this case, the adapter may either house a fluidic amplifier insert 14 and have a hole communicating with its radial bore 24 or it may itself be designed to serve as the fluidic amplifier, the bores 20 and 24 being drilled in the body of the adapter.