GB2433885A

GB2433885A - Shower with back flow prevention

Info

Publication number: GB2433885A
Application number: GB0600309A
Authority: GB
Inventors: Roderick J Gibbs; Peter J H Pegden
Original assignee: Bristan Group Ltd; Bristan Ltd
Current assignee: Bristan Group Ltd; Bristan Ltd
Priority date: 2006-01-07
Filing date: 2006-01-07
Publication date: 2007-07-11
Anticipated expiration: 2026-01-07
Also published as: GB2433885B; GB0600309D0

Abstract

A shower assembly 10 comprises a water supply 12, an upstanding water supply pipe 16 in fluid communication with the water supply, an air break device 18, a shower head pipe 20 and a flexible shower hose 40 connected to the outlet of the head pipe 20. The air break device 18 comprises a water inlet and outlet and an air inlet formed between the inlet and the outlet. The water supply pipe receives water from the water supply at or near its lower end and supplies water to the water inlet of the air break device. The shower head pipe 20 receives water from the water outlet of the air break device. The water inlet of the air break device is arranged above the water outlet. The shower hose receives fluid from the shower head pipe under gravity alone.

Description

1 2433885

A SHOWER ASSEMBLY

The invention relates to a shower assembly and particularly, although not exclusively limited to, a shower assembly for use in a medical or care home environment.

In medical or other care environments it is common for patients to be washed down by care staff using showers whilst a patient is seated in a special seat arrangement over a bath. The water that drains into the bath may contain blood or infected material or faecal material. This presents a risk if the shower falls into the bath water simultaneously with some kind of negative pressure occurring in the shower water supply. In such circumstances, there is a risk that contaminated water will re-enter the mains water supply. UK water regulations state that either the shower must be incapable of falling into the bath or a suitable check must be provided to prevent backflow of contaminated water. The shower may be prevented from entering the bath either by using a rigid shower installation or by providing a flexible hose which is insufficient in length for the showerhead to reach the bath. However, that presents the problem for carers that they wish to use a shower having a flexible hose of sufficient length to ensure proper cleaning of the subject.

US Patent Number 6757920 discloses a shower unit with backflow prevention. The shower unit has a primary backilow prevention system comprising two one-way valves in the water supply line and a secondary backflow prevention system which has a third one-way valve and allows air to be drawn into the system to prevent back siphonage of dirty water into the mains. However, this device is a construction of three mechanical devices to prevent backflow. Legislation in many territories precludes use of a mechanical backflow prevention device.

It is an object of the invention to provide an improved shower assembly.

According to the invention there is provided a shower assembly comprising a fluid supply, an upstanding fluid supply pipe in fluid communication with the fluid supply, an air break device having a fluid inlet, a fluid outlet and an air inlet intermediate the fluid inlet and outlet, a head pipe having a head pipe fluid inlet and a head pipe fluid outlet, and a flexible shower hose, the fluid supply pipe being arranged to receive fluid from the fluid supply at or near its lower end and to supply fluid to the fluid inlet of the air break device, the head pipe being arranged to receive fluid into the head pipe fluid inlet from the fluid outlet of the air break device and the air break device being arranged such that the fluid inlet is above the fluid outlet, the flexible shower hose being arranged to receive fluid from the head pipe fluid outlet of the head pipe under gravity alone, the head pressure being detennined by the vertical distance between the head pipe fluid inlet and fluid outlet, and a flow limiting device arranged to limit the flow rate of fluid flowing through the fluid supply pipe to a predetermined limit equal to the flow rate of fluid from the flexible hose at the head pressure, whereby the air break device is arranged at the upper end of the fluid supply pipe and the air break fluid inlet, outlet and air inlet are arranged so as to prevent back syphonage of fluid from a showerhead pipe into the fluid supply pipe.

The fluid supply is preferably the mains water supply.

The flow limiting device is preferably arranged between the fluid supply and the fluid supply pipe.

The flow limiting device preferably limits the fluid flow rate in the fluid supply pipe to a flow rate in the range of 1 litre per minute to 6 litres per minute, preferably one and a half litres per minute to 4 litres per minute and most preferably 3 litres per minute.

In a preferred embodiment the head pipe surrounds the fluid supply pipe and is most preferably arranged concentrically therewith. The vertical distance between the head pipe fluid inlet and the head pipe fluid outlet may be from 0.5 metres to 3 metres and is preferably around 1.5 metres.

The air break device preferably includes three or more air inlets. The air break device preferably includes a skirt which depends outwardly and downwardly from the outer body of the air break device so as to surround the air inlets. The air break device may include a deflector surface therewithin so as to deflect fluid emerging from the fluid supply pipe towards the head pipe fluid inlet.

The air break device may be equipped with an overflow reservoir. The overflow reservoir is preferably arranged so that in the event of an overflow from the fluid supply pipe, the overflowing fluid flows out of the air inlet apertures and into the overflow reservoir. A sensor means may be provided in the overflow reservoir to indicate the existence of an overflow. The overflow may include a fluid outlet which, preferably, directs fluid in the overflow to a drain in a visible manner.

A shower assembly in accordance with the invention will now be described in detail by way of example and with reference to the accompanying drawings, in which: Figure 1 is a schematic section through a shower assembly in accordance with the invention; Figure 2 is a view similar to Figure 1 showing the shower assembly during a negative mains pressure event; Figure 3 is a sectional view of a further shower assembly in accordance with the invention; Figures 4 and 5 are views similar to Figure 3 illustrating the shower assembly of Figure 3 in nonnal operation and in back siphon operation respectively; Figure 6 is a sectional view through an alternative shower assembly in accordance with the invention.

In Fig.1, a shower assembly 10 comprises a water supply 12 connected via a flow limiting device 14, such as a flow regulator, to an upstanding supply pipe 16. The supply pipe 16 has an air break device 18 at the upper end thereof. The air break device 18 is carried by a head pipe 20 which surrounds the supply pipe 16.

The water supply 12 is a mains water supply and supplies either cold water for heating by a thermostatically controlled heater (not shown), separate hot and cold water streams for mixing in a thermostatic mixer valve (not shown) or a pre-mixed warm water stream.

The supply pipe is approximately l.5m in length and extends from an inlet 22 which receives water from the flow limiting device 14 to an outlet 24 which is located inside the air break device 16.

The head pipe 20 is slightly shorter than the supply pipe 16 so that the upper end of the supply pipe 16 protrudes from the upper end of the head pipe 20. The air break device 18 is mounted at the upper end of the head pipe 20.

The air break device 18 comprises a hollow cylindrical body 26 defined by a tubular side wall 28 and a circular top wall 30 which closes off the cylinder. A bottom wall 32 has an aperture 34 which allows passage of the supply pipe 16 therethrough with sufficient radial clearance to allow water to flow around the outer surface of the supply pipe 16 and into the head pipe 20.

The air break device 1 8 is mounted to the upper end of the head pipe 20 by any suitable mounting method. The aperture 34 defines an inlet 35 for the head pipe 20.

Air holes 36 are formed through the side wall 28 of the air break device body 26 at a position intermediate the head pipe inlet 35 and the supply pipe outlet 24. The uppermost part of the holes 36 is a distance D from the supply pipe outlet 24 (see Fig.2). The distance D is at least 26mm and is preferably in excess of 30mm. An annular fluid guide formation 37 extends inwardly from the inside surface of the side wall 28 just above the holes 36 towards but short of the supply pipe 16.

The head pipe 20 extends from the inlet 35 thereof downwardly around the supply pipe 16 to an outlet 38. The outlet 38 supplies water to a flexible shower hose 40 which, in turn, supplies water to a shower head 42.

The shower assembly 10 is arranged over a bath 44 which has a fill level 46.

The flow limiting device 14 is preset to limit flow into the supply pipe 16 to a preset limit. The preset limit is determined by the flow rate of water from the shower head 42 at the pressure created by the head of water in the head pipe 20. For example, typically for a head pipe 2m in height between inlet 35 and outlet 38 and using a conventional non-massage shower head, the flow rate might be 3 litres per minute.

In use, the shower is turned on and water flows up the supply pipe 16, into the air break device 1 8 and on, into the head pipe 20. The head pipe 20 provides a head of water which flows out of the shower head 42 under gravity via the flexible hose 40.

In the event of negative means pressure (see Fig.2), the water in supply pipe 16 is drawn back into the mains. This is clean water. Air is then drawn through the holes 36 to create an air break between the supply pipe 16 and the head pipe 20. That prevents potentially contaminated water from flowing back up the head pipe 20 and into the supply pipe 16.

Figs.3 to 5 illustrate in more detail an embodiment of the invention. Parts corresponding to parts in Figs. 1 and 2 carry the same reference numerals.

In Fig.3, the shower assembly 10 is similar to that shown in Fig.1, having a mains water supply 12 and a flow limiting device 14 supplying water at a limited flow rate to a supply pipe 16. The supply pipe 16 is upstanding and emerges at its upper end into an air break device 18. The air break device 18 is mounted on a head pipe 20 which surrounds supply pipe 16.

The air break device 18 of Figs.3 to 5 is similar to that shown in Figs. I and 2 save for some additional features not shown in Figs. 1 and 2.

The annular fluid guide formation 37 includes an inwardly tapering part 37a to guide water emerging from the outlet 24 of supply pipe 16 towards the inlet 35 of head pipe 20.

The side wall 28 includes an annular skirt 48 which extends outwardly and downwardly from a point on the side wall 28 just above the holes 36.

The bottom wall 32 has an annular inwardly extending shoulder 50 at the upper end of the aperture 34 which facilitates mounting on the upper end of head pipe 20.

The lowen-nost part 52 of the side wall 28 is screw-threaded. An internally screw-threaded clip 54 with an aperture 56 in the base to allow passage of the head pipe 20 is provided. The cup 54 screw-threadingly engages with the screw-threaded part 52 of the side wall 28. An annular seal 58 is arranged between the lower surface of the bottom wall 32 and the cup 54. Tightening of the cup 54 onto the part 52 compresses the seal 58 against the head pipe 20 to create a watertight seal around the outer surface of the head pipe 20.

In addition, a shower head mount 60 is provided at the base of the head pipe 20.

Fig.4 illustrates the water flow through the assembly 10 in normal operation. Fig.5 shows the water flow in the event of negative mains pressure.

In Fig.6, a shower assembly 10 is shown which is identical in most respects to that shown in Figs.3 to 5 and parts corresponding to parts in Figs.3 to 5 carry the same reference numerals.

The shower assembly 1 0 of Fig.6 shares most of the features of that shown in Figs.3 to 5. 1-lowever, additionally, the air break device 1 8 is equipped with an overflow device 62.

In Fig.6, the supply pipe 16 extends rather further out of the end of the head pipe 20 than in Figs.3 to 5, the side wall 28 of the air break device 18 is longer and the bottom wall 34 is defined by the overflow device.

The overflow device 62 comprises a bowl-shaped body 64 with a circular base 66.

An aperture 68 is defined in the base 66 and a downwardly depending collar 70 extends from the base 66 around the aperture 68.

The base 66 includes a stepped, internally screw-threaded formation 72 with an annular recess 74 formed therein to receive a seal 76.

The collar 70 has an inwardly projecting annular shoulder 78 at the end thereof adjacent the base 66. The radial outer surface of the collar 70 is screw-threaded and arranged to receive the cup 54 and seal 58 to effect securing of the overflow device 62 to the head pipe 20.

A drain pipe 80 extends through the wall of the body 64.

In Fig.6, the screw-threaded lowermost part 52 of the side wall 28 screw-threadingly engages with the screw-threaded formation 72 of the device 62. Screwing the air break device 1 8 onto the overflow device 62 compresses the seal 76 to effect a waterright seal between the devices.

The shoulder 78 is seated on the end of the head pipe 20 and the collar 70 surrounds the top part of the head pipe 20. The cup 54 screws onto the screw-threaded outer wall of the collar 70 to compress the seal 58 against the wall of the pipe 20.

In use, should the flow rate from the supply pipe 16 exceed the flow from the shower head 42, the water will overflow the top of the head pipe 20 and begin to fill the air break device 1 8. Eventually the water level will reach the level of the air holes 36. At that point the water will flow out of the air holes down the side of the air break device 18 and into the bowl-shaped body 64 of the overflow device 62. The water in the body 64 will then drain through the drain pipe 80 which is preferably arranged so that the outlet is visible to a user to provide a visual alert of the overflow condition.

Some other form of alert may optionally be provided by an electronic sensor 82 in the overflow bowl 64.

Claims

CLAIMS

1. A shower assembly comprising a fluid supply, an upstanding fluid supply pipe in fluid communication with the fluid supply, an air break device having a fluid inlet, a fluid outlet and an air inlet intermediate the fluid inlet and outlet, a shower head pipe having a shower head pipe fluid inlet and a shower head pipe fluid outlet, and a flexible shower hose, the fluid supply pipe being arranged to receive fluid from the fluid supply at or near its lower end and to supply fluid to the fluid inlet of the air break device, the shower head pipe being arranged to receive fluid into the shower head pipe fluid inlet from the fluid outlet of the air break device and the air break device being arranged such that the fluid inlet is above the fluid outlet, the flexible shower hose being arranged to receive fluid from the shower head pipe fluid outlet of the shower head pipe under gravity alone, the shower head pressure being determined by the vertical distance between the shower head pipe fluid inlet and fluid outlet, and a flow limiting device arranged to limit the flow rate of fluid flowing in the fluid supply pipe to a predetermined limit equal to the flow rate of fluid from the flexible hose at the shower head pressure, whereby the air break device is arranged at the upper end of the fluid supply pipe and the air break fluid inlet, outlet and air inlet are arranged so as to prevent back siphon age of fluid from the shower head pipe into the fluid supply pipe.

2. A shower assembly according to claim I, in which the fluid supply is the mains water supply.

3. A shower assembly according to claim I or 2, in which the flow limiting device is arranged between the fluid supply and the fluid supply pipe.

4. A shower assembly according to any preceding claim, in which the flow limiting device limits the fluid flow rate in the fluid supply pipe to a flow rate in the range of I litre per minute to 6 litres per minute, preferably one and a half litres per minute to 4 litres per minute and most preferably 3 litres per minute.

5. A shower assembly according to any preceding claim, in which the head pipe surrounds the fluid supply pipe.

6. A shower assembly according to claim 5, in which the head pipe is arranged concentrically with the supply pipe.

7. A shower assembly according to any preceding claim, in which the vertical distance between the head pipe fluid inlet and the head pipe fluid outlet may be from 0.5 metres to 3 metres and is preferably around 1.5 metres.

8. A shower assembly according to any preceding claim, in which the air break device includes three or more air inlets.

9. A shower assembly according to any preceding claim, in which the air break device includes a skirt which depends outwardly and downwardly from the outer body of the air break device so as to surround the air inlets.

10. A shower assembly according to any preceding claim, in which the air break device includes a deflector surface therewithin so as to deflect fluid emerging from the fluid supply pipe towards the head pipe fluid inlet.

11. A shower assembly according to any preceding claim, in which the air break device is equipped with an overflow reservoir.

12. A shower assembly according to claim 11, in which the overflow reservoir is arranged so that in the event of an overflow from the fluid supply pipe, the overflowing fluid flows out of the air inlet apertures and into the overflow reservoir.

13. A shower assembly according to claim 11 or 12, in which a sensor means is provided in the overflow reservoir to indicate the existence of an overfow.

14. A shower assembly according to claims 11, 12 or 13 in which the overflow includes a fluid outlet which, preferably, directs fluid in the overflow to a drain in a visible manner.