FIELD OF THE INVENTION

This invention relates to valve assemblies and particularly to valve assemblies adapted to prevent backflow which also incorporate an atmospheric vacuum breaker. This invention will be described with particular reference to a garden tap but it will be readily understood that the invention has wider application in other types of valve assemblies and with all types of fluid including liquid and gases.

BACKGROUND OF THE INVENTION

The purpose of fitting backflow prevention devices to water supply systems which are connected to the mains water reticulation system is to prevent contaminated water entering into the mains water supply when normal water supply directions reverse.

Water supply authorities are well aware of the potential for contaminated water to enter the mains water supply system via taps and valves used in domestic and industrial locations. This situation may arise in a number of ways.

One example of the above occurs when there is a drop in the pressure of the mains water reticulation system resulting in the pressure at a tap being lower than atmosphere. If the tap is turned on and attached to a hose which is lying in a reservoir of water or other liquid solution this water or solution may be syphoned back into the mains water supply system. This can easily result in the syphonage of potentially contaminated water into the mains domestic water supply.

Another way in which contamination of the mains water supply can occur is when the pressure at the tap from the liquid in the hose to which it is attached is greater than the mains water supply pressure. This may occur in the case of reversed plumbing connections such as when a positive pressure device such as a pump has its outlet connected, by mistake, to the outlet of a tap which in turn is connected to the mains water supply system. The liquid being pumped from

the positive pressure device is then forced into the mains water supply system during the time the pressure exerted by the pump is greater than the mains pressure.

Therefore, some authorities require that in-line backflow prevention devices are fitted intermediate the tap and its hose so as to prevent these occurrences. A non-return (one-way) valve typically provides protection against most backflow circumstances. Double-check (dual-check) valves which comprise 2 one-way valves to prevent backflow, are used to increased protection in the circumstance of one of the valves becoming faulty.

Generally, simple non-return devices attachable to taps consist of a body with a passage therethrough, an internally threaded bore on one end of the body arranged so as to screw onto the external screw threads of a tap outlet or hose, an externally threaded annular portion on the other end of the body arranged for connection to a hose coupling, a one-way valve located interiorly of the body to prevent backflow of water into the mains system to which the tap is connected and also generally some form of locking means to prevent or at least make it difficult for the user to remove the device from the tap outlet or hose.

Backflow prevention devices may also include some form of vacuum breaker device (Fig. 1) which may open the hose to atmosphere when certain backflow conditions occur. Thus, not only does the device prevent contaminated water entering the mains water supply but the vacuum breaker device portion of the device drains the hose back to the reservoir of contaminated water. The typical condition in which this sort of device is useful is when low mains pressure is the cause of backflow.

Some specific devices used to prevent backflow of this type are known as back syphonage prevention devices and they are also sometimes referred to as atmospheric vacuum breakers, pressure type vacuum breakers and hose connection vacuum breakers. Such devices incorporate a ventilation valve which vents the pipe work to atmosphere under back syphonage

or back pressure conditions, and also generally include a one-way valve as a primary means of backflow prevention.

Furthermore the construction of atmospheric vacuum breakers is specifically suited to the fact that they are fitted downstream of the supply after the primary flow control device typically a tap valve, which has the direct consequence of not requiring the breaker to withstand the continuous pressure of the supply since the flow control device will typically be in the closed condition.

Vacuum breaker devices are typically arranged to fit a specially adapted tap outlet and also generally have some form of locking means to lock the device to the tap, to prevent or at least make it difficult for the user to remove the device from the special tap outlet.

A problem common to both vacuum breaker devices fitted in-line on a hose connected to a tap and tap adapted devices, is that it is still possible to remove the device from between the tap and the hose or the tap itself. This is often done when the device malfunctions thus restoring the tap and hose to their normal condition for normal use but without the protection of the backflow or vacuum breaker devices.

It is a further problem with prior backflow prevention devices, in general, that parts can be damaged, removed or inadvertently left out of the apparatus but the device will still allow the tap to function in the normal manner without any indication that the device is not providing the required level of safety and the original potential for contamination of the mains water supply system continues undetected.

Preferably in both the abovementioned circumstances the damaged state of the devices should be detectable from external inspection or upon normal operation of the tap however this is not provided for.

It is yet a further problem of the previously mentioned devices that they are not adapted to work with in-line tap housings which typically have standard b.s.p. threaded inlets and outlets or other well accepted pipe and hose jointing and fitting methods.

A further problem is the prohibition by many water authorities to allow these types of devices to be fitted where there exist downstream solenoid controlled valve devices. Solenoid controlled valves are widely used to control the distribution of water in garden watering, irrigation systems, and with household appliances, therefore, many potential sources of back flow are not able to be protected as well as they should be.

It is a further problem that none of these devices has ever been integrated with a tap or valve assembly to the extent so that the user is unaware of the benefits of backflow prevention and vacuum breaker devices provided therewith, but which provides a tap which feels, looks and operates like a standard tap or valve assembly. Market acceptance of a tap or valve assembly having these benefits will to some degree be dependent on the ability of such a tap to meet these requirements.

It is yet a further problem that the devices mentioned are not generally authorised by water supply authorities to be used on taps and valve assemblies, which may be left in the open valve condition continuously. Generally, relevant regulations only allow a standard tap, fitted with a typical backflow prevention device, to be left in the open valve position for periods no longer than twelve (12) hours. However, in use, this condition is not easily policed and non-conforming installations and poor installation practice is likely to occur.

One circumstance where a tap having integral backflow and vacuum breaker devices would be useful and which is required to be in the open valve condition the majority of the time, is that of a tap used to control water flow to a caravan having mains pressure water reticulation and preferably requiring water to be supplied from the mains system. However, on other occasions the tap may be used to fill buckets, or to connect to a hose for filling a swimming pool. Another example, in which a tap valve which exceeds the requirements of current regulations is needed, is when in an

industrial environment a tap valve or the like may ordinarily be usable as a general purpose tap, but which can, if need be, supply liquids over an extended period (i.e. greater than 12 hours continuously) such as when it becomes necessary to use the tap valve as a controlling valve for a boiler, processing tank or container filling operation.

BRIEF DESCRIPTION OF THE INVENTION

The inventor has recognized that to overcome some of the problems described it is advantageous to rearrange the configuration of the user operable flow control means, non¬ return valves and atmospheric vacuum breaker devices while it is further preferable to confine them to the body of a valve assembly, so as to make these new arrangements convenient and simple to install and simple to use and maintain.

In the descriptions that will follow the term liquid will be used in the context of the embodiment however it will be apparent that the valve assembly may be adapted to use for handling gases and consequently the term fluid will be used in it broadest sense elsewhere in the document.

Also in the descriptions that will follow the convention for describing the direction of flow is:- with respect to the inlet of the valve assembly, flow originating normally from the mains supply proceeds downstream from the inlet to the outlet and flow which proceeds from the outlet towards the inlet is moving upstream.

Therefore, when referring to the location of elements within the valve assembly, there may be reference to them being either downstream of the inlet or upstream of the outlet or upstream or downstream of another element respectively.

The first and most basic of these rearrangements is depicted schematically in Fig. 2 which shows a vacuum breaker device which comprises an integral non-return valve located

upstream of a user operable valve control means wherein the non-return valve of the vacuum breaker device is biased to close against the flow of fluid from the supply. This arrangement has a number of advantages which comprise: a) substantially constant supply pressure is exerted on the vacuum breaker device whether the valve control means is open or closed, b) providing mains pressure is greater than atmosphere, the vacuum breaker air ports (not shown) are closed whether the valve control means is open or closed, thus allowing the assembly to operate under constant supply pressure, and c) when the valve assembly is arranged to close off the flow and a hose is connected to the outlet of the assembly which happens to be in fluid communication with a reservoir of fluid, back syphonage of the contents of that reservoir will not occur as is likely in prior art arrangements.

The second of these variations is depicted schematically in Fig. 3 which shows a vacuum breaker device comprising an integral non-return valve located upstream of the valve assembly outlet wherein the non-return valve is biased closed but which is limited in its movement to allow flow of fluid through the valve assembly by a user operable valve control means. The valve control means may in one example comprise a spindle with a user operable handle which when turned to a position to allow limited movement of the non-return valve further allows flow of the fluid from the supply through the valve assembly or maintains the non-return valve closed to restrict the flow from the supply. While the functions of two independent valves have been combined into one valve the independence of those two functions has not been compromised such that the vacuum breaker device and one way check valve functions will operate as normal regardless of the flow control means position other than when the valve is forced closed. This arrangement has a number of advantages

additional to those described previously for the arrangement depicted in Fig. 2 which comprise: d) fewer parts allowing for lower cost and more compact arrangement, e) lower flow resistance hence lower pressure drop across the valve apparatus, f) the flow control means is made easier to turn to a closed position because the supply pressure assists closure of the flow control means and not against supply pressure as in prior art flow control means, and, g) of the variety of failure modes that may occur to the vacuum breaker device in this arrangement, unlike prior art valve assemblies, the failure will be visibly apparent by the escape of fluid out of the atmospheric vent of the vacuum breaker device.

The third of these variations is depicted schematically in Fig. 4 and comprises the addition of a second non-return valve upstream of the vacuum breaker device. This arrangement has the further advantage of: h) increasing the level of backflow protection afforded to the supply side of the valve assembly, thereby increasing the ability of the device to meet more stringent regulations which require a minimum level of supply side protection in back flow conditions. The fourth of these arrangements is depicted in Fig. 5 and is conceptually identical to the third arrangement but offers an alternative construction.

The fifth of the these arrangements is depicted schematically in Fig. 6 which shows a vacuum breaker device upstream of the valve assembly outlet and a second non-return valve further downstream wherein the second non-return valve is biased closed to allow flow through the valve assembly by a user operable valve control means. This arrangement has a further advantage which relates to the possibility of using

flow control means which are not easily or economically adaptable to the control of the non-return valve of the vacuum breaker device.

SUMMARY OF THE INVENTION

In one form of the invention, a valve assembly comprises a housing having a flow passage, inlet and outlet portions and an orifice through which fluid passes downstream from said inlet to said outlet, a primary check valve located intermediate said inlet and said outlet adapted for blocking the passage of fluid flowing upstream from said outlet to said inlet but allowing fluid to flow from said inlet to said outlet, a user operable valve means located downstream of said primary check valve which is operable by a user of said valve assembly to control the flow of fluid through said flow passage by opening or closing said user operable valve means.

In a further form of the invention, a valve assembly comprises a housing having a flow passage, inlet and outlet portions and an orifice through which fluid passes downstream from said inlet to said outlet, a valve seat adjacent or surrounding said orifice, a primary check valve located intermediate said inlet and said outlet adapted for blocking the passage of fluid flowing upstream from said outlet to said inlet but allowing fluid to flow from said inlet to said outlet, a user operable valve means located downstream of said primary check valve which is operable by a user of said valve assembly to control the spacing of said primary check valve from said valve seat to control the flow of fluid through said flow passage.

In yet a further aspect of the invention said valve assembly further comprises said primary check valve having a vacuum break means integral therewith.

In yet a further aspect of the invention said valve assembly according to any of the preceding aspects has a secondary check valve located upstream of said primary check valve.

In yet a further aspect of the invention said valve assembly according to some of the preceding aspects has a secondary check valve located downstream of said primary check valve.

In a further form of the invention, a valve assembly comprises a housing having a flow passage, inlet and outlet portions and an orifice through which fluid passes downstream from said inlet to said outlet, a valve seat adjacent or surrounding said orifice, a primary check valve located intermediate said inlet and said outlet adapted for blocking the passage of fluid flowing upstream from said outlet to said inlet but allowing fluid to flow from said inlet to said outlet, a user operable valve means located downstream of said primary check valve which operable by a user of said valve assembly to control the spacing of said primary check valve from said valve seat to control the flow of fluid through said flow passage, and a secondary valve means adapted for blocking the passage of fluid flowing upstream from said outlet to said inlet but allowing fluid to flow from said inlet to said outlet integral with a vacuum breaker device, located upstream of said primary check valve.

In yet a further form of the invention said user operable valve means further comprises a spindle rotatable by a user of said valve assembly.

In this form of the invention said primary check valve may comprise a jumper valve arranged to slidably fit within an internal bore of said spindle whereby, independent of the position of said spindle, said jumper valve is moveable to block the passage of fluid flowing upstream from the outlet towards the inlet.

Furthermore, in this form of the invention, said jumper valve may comprise a shaft sized to slidably fit within an internal bore of said spindle, said shaft further comprising a fluid communications means which allows fluid to communicate between said flow passage and said bore in said spindle.

In form of the invention said primary check valve may further comprise a biasing means such as preferably a spring located internal to said spindle bore which biases said jumper valve away from said spindle.

Alternatively, said primary check valve may comprise a biasing means such as preferably a spring located within the housing of the valve assembly which is arranged to bias said jumper valve away from said body.

In a further aspect the housing may comprise two connectable parts.

In yet a further aspect the of a two part valve assembly housing a first part of said housing contains said primary check valve and a second part of said housing contains said second check valve.

In yet a further aspect the of a two part valve assembly housing a the second part of said housing further contains a vacuum breaker device.

In a further aspect of the invention the vacuum breaker device comprises a diaphragm biased into a position which in use is adapted to lie in its least stressed position most of the time.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described by way of example only using a tap as illustrated in the accompanying drawings in which:

Fig 1 depicts a schematic of a prior art valve assembly configuration;

Fig 2 depicts a schematic of a valve assembly configuration showing the user operable valve means located downstream of an integral primary check valve and vacuum breaker device;

Fig 3 depicts a schematic of a valve assembly configuration showing the user operable valve means located downstream of and arranged to control the primary check valve of the vacuum breaker device combination;

Fig 4 depicts a schematic of a valve assembly configuration showing the user operable valve means located downstream of and arranged to control the primary check valve of the vacuum breaker device combination plus a secondary check valve located upstream of said primary check valve and vacuum breaker device combination;

Fig 5 depicts a schematic of a valve assembly configuration showing the user operable valve means located downstream of and arranged to control the primary check valve of the vacuum breaker device combination plus a secondary check valve located downstream of said primary check valve and vacuum breaker device combination;

Fig 6 depicts a schematic of a valve assembly configuration showing the user operable valve means located downstream of and arranged to control the primary check valve plus a secondary check valve and vacuum breaker device combination located upstream of said primary check valve and user operable valve means combination.

Fig 7 is a section view of an embodiment of Fig. 3 in an open condition;

Fig 8 is a section view of an embodiment of Fig. 3 where the pressure at the inlet is less than or equal to the pressure at the outlet, depicting the independent operation of the primary check valve and the user operable valve means;

Fig 9 is a section view of an embodiment of Fig. 3 depicting the user operable flow control valve positioned to close the primary check valve means;

Fig 10 is a section view of an embodiment of Fig. 3 depicting the independent operation of the primary check valve and the user operable valve means which is retracted to allow the primary check valve to open and of course close should back syphonage or backflow occur;

Fig 11 is a section view of an embodiment of Fig. 3 depicting an alternative primary check valve arrangement using a loose jumper valve spring loaded from inside the spindle of the user operable valve means;

Fig 12 is a section view of an embodiment of Fig. 5 depicting a check valve referred to in this embodiment as the primary check valve since it is the most downstream valve in the valve assembly and is located downstream of the combined vacuum breaker device and user operable valve means;

Fig 13 is a section view of an embodiment of Fig. 4 depicting a check valve referred to in this embodiment as the secondary check valve located upstream of the combined vacuum breaker device and user operable valve means;

Fig 14 is a section view of an embodiment of Fig. 6 depicting the valve assembly in an open condition with vacuum breaker device located upstream of a user operable valve means;

Fig 15 is a section view of an embodiment of Fig. 6 depicting the valve assembly in a closed condition;

Fig 16 is a section view of an embodiment of Fig. 6 depicting the valve assembly in a closed condition caused by backflow at the outlet while the tap is turned on, but with no flow downstream caused by the double action of the two check valves;

Fig 17 is a section view of an embodiment of Fig. 6 depicting the valve assembly in closed condition caused by backflow pressure rising above the mains water pressure;

Fig 18 is a section view of an embodiment of Fig. 6 depicting the valve assembly in a venting condition caused by backflow pressure rising above the mains water pressure and an ineffective primary check valve;

Fig 19 is a section view of an embodiment of Fig. 6 depicting the valve assembly in a back siphonage condition after the user operable valve means was initially open allowing air to enter the valve assembly in preference to fluid from the valve assembly outlet side of the secondary check valve;

Fig 20 is a section view of an embodiment of Fig. 6 depicting the valve assembly having an ineffective primary check valve and showing a back siphonage condition;

Fig 21 is a section view of an embodiment of Fig. 6 having ineffective primary and secondary check valves depicting the valve assembly in a back siphonage condition;

Fig 22 is a section view of an embodiment of Fig. 6 depicting a ball valve embodiment of a user operable valve means;

Fig 23 is a section view of a further embodiment of Fig. 3 depicting a spring loaded spindle bottom end;

Fig 24 is a section view of an embodiment of Fig. 6 depicting the secondary check valve and vacuum breaker device in a different configuration from that depicted in Figs 14-21;

Fig 25 is a section view of an embodiment of Fig. 6 depicting a different spring arrangement for the primary check valve than that depicted in Figs 14-21 in an angled valve assembly body;

Fig 26 is a section view of an embodiment of Fig. 6 depicting a different spring arrangement for the primary check valve than that depicted in Figs 14-21 and a sliding secondary valve arrangement in a stand pipe valve assembly body;

Fig 27 is a section view of an embodiment of Fig. 6 depicting a different spring arrangement for the primary check valve than that depicted in Figs 14-21 in a wall mount valve assembly body;

Fig 28 is a perspective view of one embodiment of the valve assembly in the form of a tap for stand pipe fitting; and

Fig 29 is a side view of the stand pipe tap embodiment of Fig 28;

Fig 30 is a section view of a conventional diaphragm arrangement with no flow;

Fig 31 is a section view of a conventional diaphragm arrangement with flow;

Fig 32 is a section view of a suggested diaphragm arrangement with no flow;

Fig 33 is a section view of a suggested diaphragm arrangement with flow; and

Fig 34 is a section view of a further embodiment of Fig. 2 showing a standard tap having an engageable constant pressure vacuum breaker assembly.

DETAILED DESCRIPTION OF THE INVENTION

To assist in the understanding of this invention the use of like numerals will be used on like elements depicted in the Figures and described accordingly in the specification.

A valve assembly according to the invention may be used for many purposes. However, in this description, a user operable tap of the type found in domestic water reticulation is used by way of example only and is not meant to be limiting in any way upon the scope of any claims to the invention.

As previously described, the inventor has recognized that to overcome some of the problems described it is advantageous to rearrange the configuration of the user operable flow control means, which in this embodiment comprises a spindle operable with a tap handle attached thereto, non-return (check) valves and (atmospheric) vacuum breaker devices while it is further advantageous to confine the user operable flow control means to the body of a valve assembly, in this embodiment a tap, so as to make these new arrangements convenient and simple to use.

Figs. 1-6 have previously been described.

Fig 7 depicts the tap 10 having a substantially conventional outer form comprising a unitary tap body 11 with a passage 12 therethrough extending from an inlet 13 to an outlet 14. However, a unitary body is only a preferable embodiment since a two part body is manufacturable as is number of variations thereof one example being depicted in Fig 34 showing a two part body having an arrangement of parts as pictorially shown in Fig. 2.

Water flows downstream from the inlet 13 to the outlet 14 as depicted by the arrows numbered 15-

However, Fig 7 shows the tap in an abnormal condition since the primary check valve 16 is raised from its biased resting position. The biased resting position is shown clearly in Figs 12 and 13. The bias of the primary check valve is provided by the primary check valve return spring 32.

The primary check valve 16, so called because it forms the first valve closure means operable to stop the backflow of water from the outlet to the inlet.

The arrangement depicted is of a tap spindle adapted to rotate relative to the tap body 11 to raise and lower the spindle 21 and its bottom end 31. However, a further arrangement is for the bottom end 31 of the tap spindle 21 to be separate and slidably fit within an internal bore of the tap spindle 21.

When the spindle 21 is in a raised position, the primary check valve 16 is urged, by the mains water pressure, off the diaphragm 23 to allow the flow of water through the passage 12 of the tap housing. When the spindle 21 is in a lowered position (as depicted in Fig 9) the primary check valve 16 is urged by the spindle 21 against the diaphragm 23 to stop the flow of water through the passage 12 of the tap housing.

Referring to Fig. 7, under normal mains pressure conditions the force applied by mains water onto the upstream side of diaphragm 23 is such that it is urged away from carrier 24 until it contacts the air vent sealing lip 42. Further the diaphragm support ring 29 has been urged against

the diaphragm spring 30, until it contacts the air vent support face 44. Here the diaphragm support ring 29 stops and resists any further movement of the diaphragm 23 due to the force applied to the diaphragm by mains pressure.

With the diaphragm 23 fully and tightly sealing against the path of mains pressure water to the air vent 28, mains pressure now urges the primary check valve 16 away from the inner edge portion 33 of the diaphragm 23, against the force of spring 32. This allows the flow of water through passage 12.

The diaphragm 23 will remain stable in its position of sealing the air vent 28, provided the force exerted by mains pressure on its upstream surface is greater than the sum of the forces acting on its downstream surface. Those forces are:-

1. Spring 32 force,

2. Spring 30 force,

3. Atmospheric pressure on the exposed area of diaphragm 23,

4. The mass of the diaphragm support ring 29,

5. The force of any water above the primary check valve 16, and,

6. The resilience of the diaphragm 23.

When the sum of all these forces is equal to the force provided by mains pressure the seal will be indeterminate but the diaphragm 23 will likely not move.

When the sum of all these forces is greater than the force provided by mains pressure, then diaphragm 23 will be urged back towards the carrier 24 and this will open air vent 28 to the passage 12.

To close the tap the tap spindle 21 is rotated to lower it with respect to the tap body 11 and thereby place the bottom end 31 of the spindle against the top surface of the primary check valve 16.

Fig 8 depicts the tap 10 with the primary check valve 16 and the diaphragm in the position they would assume if the pressure at the inlet 13 of the tap was less than or equal than the pressure at the outlet 14 of the tap. The primary check valve and the vacuum breaker device operate independently of the position of the bottom end 31 of the tap spindle.

Fig 8 also depicts the tap as it would be after fitting to the pipework but before mains pressure water is applied. The spindle 21 has been wound down as far as the spindle circlip 45 will allow and the primary check valve is positioned as shown because of the force exerted upon it by the diaphragm spring 30 and distention of the diaphragm towards the carrier 24. In this position the air vent is open and atmospheric pressure is communicated to the tap passage 12 downstream of the primary check valve 16.

When water enters the tap at mains pressure it passes through the carrier passages 26 and exerts its pressure against the diaphragm causing it to distend in a downstream direction until its top surface comes into contact with the vent sealing lip 42 closing the vent 28.

Concurrently, the water pressure will act on the underside of the primary check valve 16 urging it against the return spring 32 and further downstream, requiring more force than that needed to move the diaphragm against it own resilience and, as a result of this, the primary check valve will remain sealingly in contact with the diaphragm until the diaphragm itself has been restrained by the vent sealing lip as described previously.

A seal is maintained between the primary check valve and the diaphragm and, as the spindle is wound down, it acts against the almost constant force of the mains water pressure acting on the upstream surface of the diaphragm and primary check valve and this considerable force ensures a drip free seal with minimum effort by the operator to turn the tap to a closed condition and likewise to turn it to an open condition.

This character of the operation of the valve assembly provides an "easy open" characteristic which can be useful to those who normally find the action of turning on and off taps difficult.

At this point, if the spindle is wound down to meet the top face of the primary check valve, the valve will be restrained and the condition of the tap will be as depicted in Fig 9.

Control of the amount of flow through the tap is determined by the distance the bottom of the spindle 31 is raised above the primary check valve 16 top surface in a similar fashion to that of a conventional tap.

In the event of mains pressure falling and approaching atmospheric pressure, the primary check valve return spring 32 will at some point overcome the force applied to the primary check valve by the water flow and will urge the check valve in an upstream direction until it contacts the inner edge portion of the diaphragm and flow will cease.

If mains pressure continues to fall, the primary check valve return spring 32 will overcome the resistance of the diaphragm 23 and the movement of both will unseal the air vent 28 as well as continue to urge the valve towards the carrier 24. In this condition, the mains system via the tap inlet is isolated from the remainder of the tap downstream of the primary check valve, where atmospheric air pressure is present, creating a vacuum break and allowing any water in the outlet of the tap and any hose which may be connected to it to drain away safely to its intended source. This condition is sometimes referred to as a back syphonage condition and as can be seen the tap provides protection from such conditions regardless of the position of the spindle, that is whether the tap is in the open or closed condition.

A further cause for potentially dangerous backflow conditions is back pressure which occurs if the tap outlet is accidently connected to a fluid source having a pressure equal to or greater than the pressure of the water being accepted at the inlet of the tap.

For example, referring to Fig 10, assume the pressure at the outlet 14 of the tap rises to approach mains pressure. At some point the primary check valve 16 will move back to contact the inner edge portion 33 of the diaphragm under the influence of the diaphragm spring 30 and water flowing downstream will cease. If the pressure at the outlet continues to rise, at a further point the pressure exerted on the downstream side of the diaphragm and the primary check valve will be greater than the mains pressure exerting its force on the upstream side of them. When this occurs the primary check valve and the diaphragm will together move away from the vent sealing lip and the pressurised fluid will exit the tap housing through the vent 28 and thus this fluid is prevented from entering the mains pipework.

Fig 9 depicts the tap spindle 21 turned to place the tap in the closed condition while connected to a water supply, typically at mains pressure, but the pressure of which need only be greater than the forces described earlier. The spindle has been screwed down to a point which stops the primary check valve moving away from the seal formed between the primary check valve and the inner edge portion of the diaphragm, which is assisted by pressure from the water supply on the upstream side of the diaphragm. This arrangement makes the feel of the tap to the user much like a conventional tap. The spindle circlip 45 is located on the spindle and is preferably located so as to limit the maximum depth to which the bottom end of the tap spindle 31 can force the primary check valve down against the diaphragm and its carrier 24. It has been found though that, even without the movement limiting circlip, the user is likely to cease turning the tap spindle before the above occurs since the tap flow will have ceased and the tap will feel closed.

Fig 10 depicts the tap 10 in an open condition and with normal mains pressure and the spindle raised, the primary check valve being urged by the mains pressure away from the diaphragm inner edge portion thus allowing water to flow from the inlet to the outlet. In this open condition the

diaphragm is held sealingly against the vent sealing lip 42 by the difference between mains pressure on the upstream side of the diaphragm and the atmospheric pressure on the vent side of the diaphragm.

Fig 11 depicts an alternate primary check valve arrangement comprising a loose jumper valve 46 which may or may not have spring bias means in the form of, in this embodiment, a jumper valve spring 47. This arrangement is useful in some applications but in no way alters the principle of the valve apparatus operation.

In some circumstances the level of backflow protection required is greater than that which can be provided by only one check valve and a vacuum break device. In those circumstances Fig 12 depicts one embodiment of an arrangement also shown schematically in Fig 5, which provides an additional check valve fitted to the outlet portion of the tap and raises the protection level to that of a vented double check valve. The arrangement is particularly easy to incorporate into the tap and may be made difficult to remove by known methods of fitting and fixing. In this arrangement the check valve fitted to the inlet of the tap is referred to as the primary check valve since it is the first valve to actuate in backflow and back syphonage conditions.

Fig 13 depicts a specific embodiment of the schematic of Fig 4 and shows the user operable valve means which, in this embodiment, is a tap spindle 21 located downstream of and controlling the maximum degree of movement of the primary check valve 16 of the vacuum breaker device, plus a secondary check valve 17 located upstream of the primary check valve 16. The arrangement shown for the secondary check valve is particularly easy to incorporate into the tap at its inlet region by standard thread engagement means and may be made difficult to remove by know methods of fitting and fixing. It is a further advantage to have the elements arranged to fit compactly into tap body 11 so as to improve the aesthetics of the tap overall.

The elements used in the embodiment of the invention depicted in Figs 14-22 and 24-27 comprise two independent check valves mounted within a tap housing having intermediate those valves a vacuum breaker device, wherein a) a flow control means comprises a primary check valve adapted to operate with a tap handle to control the flow of fluid through the tap and b) the secondary check valve and vacuum breaker device are upstream of the flow control means.

In the arrangements depicted in Figs 14-22 and 24-27, the check valve fitted to the spindle of the tap is referred to as the primary check valve since it is the first valve to actuate in backflow and back syphonage conditions.

The elements described in the second preceding paragraph arranged in the configurations shown and described are able to be used in a tap which in general is left on continuously but which may be turned off as required. This configuration, as will be explained in detail later in the specification, does not spit or leak liquid when turned off or on; operates normally in conjunction with the operation of downstream solenoid devices; will not leak liquid when the reservoir at the hose end is located above the level of the tap, whether the tap is closed or open; will leak indicating a fault with the tap assembly when any of the valves located in the tap is faulty or has been tampered with; and will not operate correctly and will indicate its nonstandard state by leaking via the vacuum breaker device when it is damaged or parts have not been fitted or have been incorrectly fitted.

Other features and benefits of this embodiment of the invention will become apparent as particular illustrative examples are described hereafter.

One embodiment of the invention is shown in Figs 14 to 21, which depict various conditions of operation of a tap fitted in a garden/domestic environment and which is connected to the mains water supply at its inlet.

Fig 14 depicts the tap 10 in the normal open condition having a substantially conventional outer form comprising a tap body 11 with a passage 12 therethrough extending from an inlet 13 to an outlet 14. Water flows downstream 15 from the inlet 13 to the outlet 14 as depicted by the arrows numbered 15.

There exist two check valves, a primary check valve 16 and a secondary check valve 17, which are urged by the mains water away from their respective passage closure means to allow the flow of water from the inlet 13 to the outlet 14.

The primary check valve 16, so called because it forms the first valve closure means operable to stop the backflow of water from the outlet to the inlet, comprises a substantially conventional tap jumper valve 18 at the end of the spindle 21 in its shank 19. The shank of the jumper valve 19 slidably fits within an internal bore 20 of the tap spindle 21 which is adapted to rotate relative to the tap body 11 to raise and lower the spindle.

When the spindle 21 is in a raised position the primary check valve 16 is urged by the mains water pressure off the valve seat 22, which is adjacent or surrounds an orifice 22a, thus allowing the flow of water through the passage 12 of the tap housing. When the spindle 21 is in a lowered position, the primary check valve 16 is urged by the spindle against the seat 22 to stop the flow of water through the passage 12 of the tap housing.

Under normal mains pressure, the force applied by mains water onto the upstream side of diaphragm 23 is such that it is urged away from carrier 24 until it contacts the air vent sealing lip 42. In doing this it has also carried the secondary check valve 17 away from carrier 24. The valve is still sealingly in contact with the inner edge portion 33 of the diaphragm. Further the diaphragm support ring 29 has been urged against the diaphragm spring 30, until it contacts the air vent support face 44. Here the diaphragm support ring 29 stops and resists any further movement of the diaphragm 23 due to the force applied by mains pressure.

With the diaphragm 23 fully and tightly sealing air vent 28, mains pressure now urges the head end 27 of the secondary check valve 17 away from the inner edge portion of the diaphragm 33, against the force of spring 32. This allows the flow of water through passage 12.

The diaphragm 23 will remain stable in its position of sealing the air vent 28, provided the force exerted by mains pressure on its upstream surface is greater than the sum of the forces acting on its downstream surface. Those forces are:-

1. Spring 32 force,

2. Spring 30 force,

3. Atmospheric pressure on the exposed area of diaphragm 23,

4. The mass of the diaphragm support ring 29,

5. The force of any water between the primary and secondary check valves that is acting on the top 35 of the secondary check valve, and,

6. The resilience of the diaphragm 23.

When the sum of all these forces is equal to the force provided by mains pressure the seal will be indeterminate but the diaphragm 23 will likely not move.

When the sum of all these forces is greater than the force provided by mains pressure, then diaphragm 23 will be urged back towards the carrier 24, thus opening air vent 28.

To close the tap the tap spindle 21 is rotated to lower it with respect to the tap body 11 and place the bottom end 31 of the spindle against the top surface of the tap valve 18 and urges its bottom surface towards the valve seat 22. When the tap valve is abutting the seat, water flow from the valve seat to the outlet is stopped and as schematically depicted in Fig 15, the water pressure in the space between the primary check valve 16 and the secondary check valve 17 tends to equalise with the mains water pressure behind the secondary check valve.

With the diaphragm in this position and with the assistance of the mains pressure behind it, a watertight seal is maintained between the interior of the tap body, comprising the space between the primary check valve and the tap inlet, and the air vent 28. This arrangement avoids the common problem with prior art valve assemblies of spitting of water via the air vents each time a tap is opened or closed.

Turning now to Fig 16, the condition depicted is an example of when the water flow through an opened tap is stopped. Stoppage of flow may be caused by the closing operation of a solenoid valve along the hose or pipe connected to the outlet of the tap or the manual closing of a sink tap in the caravan to which the hose is connected, or the operation of a hand held sprinkler or hose water gun at the end of the hose or alternatively the hose becoming kinked or squashed such that flow is restricted.

In this condition, both check valves 16 and 17 are open and the pressure throughout the tap equalises to mains pressure. Under the influence of its own weight, in the case of the primary check valve 16, the primary check valve return spring 47, which is only depicted in Fig 16 since it is not essential to the working of this action but may be used to assist this action, and in the case of the secondary check valve 17, under the influence of the secondary check valve spring 32; these check valves return to their seats. In the case of the primary check valve, the seat is valve seat 22, while in the case of the secondary check valve, the seat is the inner edge portion 33 of the diaphragm 23. Note that the two valves will move independently of one another and that the diaphragm maintains the seal between the air vent 28 and the interior of the tap body 11.

In Fig 17 the condition depicted is an example of a back flow condition which, in this particular situation, is created when the tap inlet is connected via a hose to a supply of liquid having a pressure greater than the mains water pressure at the tap inlet.

In this condition a backflow of liquid through the tap will occur unless the primary, and/or in the event of its failure, the secondary check valves move to close off the flow of potentially harmful liquid into the mains water supply.

In the above condition the pressure exerted by the back flowing liquid on the top surface of the tap jumper valve 18 will urge the jumper valve towards the valve seat 22 independent of the position of the tap spindle 21 until the passage 12 is closed off as shown in Fig 17.

The larger the backflow pressure the better the seal and thereby the greater protection against contamination of the mains supply by potentially contaminated liquid.

Fig 18 depicts a condition where the primary check valve 16 is faulty or is hindered in some way so that the seal previously described is not effective to stop the back flow of liquid. In Fig 18 this condition is depicted as resulting from a foreign body 34 located between the tap jumper valve sealing part 18 and the valve seat 22.

Backflow pressure is therefore applied to the secondary check valve 17 which moves downward to its valve seat upon the diaphragm 23. When the combined force of the diaphragm spring 30 via the diaphragm support ring 29 and the backflow pressure against the upper surface of the head end 35 of the secondary check valve and the exposed upper surface of the diaphragm 23 itself, is greater than the mains pressure, the diaphragm is unseated from the air vent, and, as shown, the liquid flowing upstream exits the tap body 11 via the air vent 28.

The specific arrangement of the air vents is not critical to the invention suffice to note that there may be more than one exit aperture in the body of the tap 11 and preferably the aperture has a downward attitude with respect to the ground above which the tap is located to minimise the fouling of its opening by foreign matter lodging in it from

above. In some areas, this preferable feature may however be a required feature of the product so that it may conform to various regulations.

If backflow pressure is sufficient, the diaphragm will be urged against mains pressure until it contacts the carrier 24. When the diaphragm in combination with the head of the secondary check valve are forced against the carrier by the backflow pressure, the backflow of potentially harmful liquid into the mains water supply is prevented and the faulty condition of the tap, hose and mains water supply connection arrangement is indicated by the outflow of liquid from the air vents of the tap.

Fig 19 depicts a situation where the mains water supply is at less than atmospheric pressure, which may result in backsyphonage of the reservoir of liquid in which a hose is lying while connected to a tap which is turned on, which may result in the contamination of the mains supply with liquid from the reservoir.

However, in this embodiment, as the pressure on the inlet/mains water supply side of the diaphragm decreases, the atmospheric pressure created as air enters the air vent 28 creates a pressure on the primary check valve side of the diaphragm 23 which is great enough when combined with the pressure exerted by the diaphragm spring 30 and other forces acting in opposition to mains pressure to cause the diaphragm 23 to collapse against the carrier 24.

While the mains pressure remains at a level less than the secondary check valve return pressure, the valve will remain closed.

The tap is shows the spindle raised as if the tap were on but with its primary check biased valve closed so as to prevent back syphonage and the secondary check valve prevents air entering the pipework between the mains supply and the tap via the tap.

Fig 20 depicts a different aspect of the above-described circumstances which evolves from having a hose attached to the tap which may or may not be located in a reservoir of liquid and having the tap in the open flow condition.

As stated previously, the secondary check valve moves to close off the passage 12 so that, in this example air and any liquid which is in the tap and hose to which it is connected do not flow back into the mains water supply system.

Furthermore, as soon as air is admitted to the tap body it replaces the liquid between the diaphragm and the tap outlet 14 and continues replacing the liquid in the hose, thus allowing the hose to drain the liquid back to its particular source.

If, however, the pressure of the liquid in the tap from the hose is above atmospheric pressure, it will flow via the restricted/damaged primary check valve and out the air vent 28, providing a visible indication of a problem with the primary check valve.

If the primary check valve was operating correctly, it would close off the passageway and reflect the condition depicted in Fig 17, while concurrently the secondary check valve was operating to accommodate a reduction in the mains water supply pressure to a level less than atmospheric pressure.

Fig 21 depicts a most unusual condition wherein both check valves are faulty 17 or fouled 34 and mains water pressure is less than atmospheric pressure. The air vents are sized so that air flow via the vents is easier than air flow via the tap inlet and the result is for air to flow into the tap body and break the vacuum therein and be drawn into the mains in preference to any contaminated fluid which may be at the outlet, thereby preventing the contamination of the mains water supply with potentially harmful liquid.

The invention has now been described in one embodiment where the primary check valve is also used to control the flow and is located downstream of the secondary check valve.

Fig 22 depicts a further embodiment of the above described arrangement, wherein the secondary check valve is substantially as described above, while the primary check valve comprises a ball cock valve 36 having integral, within its flow passage 37, a ball primary check valve 16. Various seals and coupling means between the ball valve and its flow control handle are shown but are incidental to the operation of this configuration.

This further embodiment will have the same function as the prior described embodiment and, although the device shown in Fig 22 is an in-line version, the components described and shown may be arranged in a garden tap like body or other such enclosure and will provide a very quick 1/4 turn on-to-off and vice versa action.

Fig 23 is a variation of the concept previously described, its major difference being the use of only one check valve and the inclusion of a spring 38 within the tap spindle 21 of sufficient force to close the check valve 17\' as depicted in Fig 23, even when the tap spindle 21 is restrained from being turned lower than allowed by the circlip 45 or other equivalent movement restraint means.

This arrangement has the advantage that the feel of the tap is equivalent to a standard jumper valve non-vented tap and also the diaphragm cannot be pushed off its seat by the tap operator screwing down the tap spindle 21 further than necessary even though the water flow has been stopped.

Furthermore, such an arrangement provides for pressure relief which will dampen water hammer occurrences in the system.

Fig 24 is merely illustrative of a further configuration of the invention incorporated into a different tap body shape which has its particular application in domestic and industrial environments. The tap bodies in Figs 25-27 are also illustrative of the various shapes to which the invention may be adapted.

It is preferable although not necessary for a spring 38 like that shown in Fig 24, but of less expansive force, to be incorporated into the tap spindle internal bore of any of the configurations and embodiments described hereinbefore. This spring would have the tendency to close the primary check valve at back pressures less than those otherwise required.

It is also preferable although not necessary for the shank of the jumper valve 19 to have incorporated therein a passage or groove 40 as depicted in Figs. 14 and 23 which may communicate liquid and or air to the internal bore of the spindle so that the tap jumper valve 18 has no tendency to remain abutting the bottom end 31 of the tap spindle by way of a vacuum formed in the internal bore 20 of the tap spindle or any water surface tension between the shank of the jumper valve 19 and the surface of the internal bore 20 of the tap spindle.

Figs 25-27 also show a variation of the arrangement of the diaphragm 23 and the diaphragm support ring 29 whereby the head end 27 of the secondary check valve seats upon the ring 29 rather than the diaphragm 23 as depicted in the earlier embodiments. Furthermore, as previously described, the primary check valve spring is located within a cavity of the body of the tap and provides a constant spring force on the check valve regardless of the spindle position.

It will also be apparent that the physical separation of the flow control means of the tap from the function of the primary check valve is also possible. However, it is preferable to have the primary check valve located downstream of both the secondary check valve and air venting means. Therefore, the primary check valve may be located upstream or downstream of the flow control means as long as they are both downstream of the secondary check valve and air venting means.

Furthermore, Figs 26 and 27 depict a secondary valve 27 mounted on a sliding ring 29 such that the spring force exerted on the secondary valve is constant, whether the air vent 28 is open or closed by flow conditions.

In many prior art vacuum breaker devices a diaphragm is fitted such that mains pressure acting on the upstream side of the diaphragm stretches the diaphragm as it is urged towards the air vent sealing lip. In such cases the internal resilience of the diaphragm material is acting against the force of mains pressure and tends to lessen the sealing force between the lower edge of the check valve and the inner sealing lip of the diaphragm. This can cause water to leak from the device as the diaphragm is urged towards or away from the air vent sealing lip as a result of changing pressures within the device.

In the arrangement depicted in the drawings Figs 7 to 13, the diaphragm is arranged so that it is just closing the air vents when no forces are applied. The air vents are opened at low or zero mains pressure by arranging the one way valve to stretch the diaphragm away from the vent sealing lip at such pressures. This arrangement causes the internal resilience of the diaphragm to assist the sealing engagement of the diaphragm inner edge and the check valve lower edge while the valve and diaphragm are being urged away from the check valve support plate and towards the air vent sealing lip by any increase in mains pressure.

Such an arrangement is not essential to the operation of the device but can assist in overcoming leakage especially in devices having a small external diameter and a large air vent cross sectional area requirement.

Fig. 28 merely depicts a bottom perspective view of one external tap shape which could embody the invention, showing in particular the vent opening. Fig. 29 merely depicts a side view of the tap shape of Fig. 28.

Figs 30 to 33 depict the differences between conventional diaphragm arrangements and one of the suggested arrangements of the invention, particularly as referred to in Figs 7 to 13.

Fig 30 depicts a conventional diaphragm arrangement showing the check valve biased against the diaphragm when mains pressure is very low or zero indeed this bias would

locate the diaphragm in this position if there were no other forces in play. However, the least amount of time of the operation of the diaphragm is spent in this position. Fig 31 depicts the same conventional diaphragm, showing the check valve raised by the mains pressure along with the diaphragm which is distended out of its biased condition and located to seal the atmospheric vents. However, this is a position that may need to be adopted for an extended period of time and over time the resilience of the diaphragm will be detrimentally affected. This is one of the reasons previous vacuum breaker devices have not been located upstream of the primary check valve or indeed allowed to because they failed to meet strict regulations in this regard.

Fig 32 depicts the diaphragm of the invention in a distended condition when the check valve is biased against it but which only occurs when mains pressure is very low or zero or when there is back syphonage or back pressure at the diaphragm. This condition is only going to arise when these potentially hazardous conditions occur, which means that the diaphragm is only stressed on an occasional basis if at all.

Fig 33 depicts the suggested arrangement of the invention as particularly shown in Figs 7 to 13, showing the check valve raised by the flow pressure and the diaphragm in an unstressed condition even though flow is occurring. In Figs 14 to 27 the diaphragm is shown in a different arrangement but where the predetermined bias of the diaphragm is such that the diaphragm lies in its least stressed position most of the time.

Fig. 34 shows a conventional tap body 11a having a unitary tap body containing a conventional of modified jumper valve in accordance with the requirements of the invention. The second part of the tap body lib depicted in Fig 34 is conventional screwed onto the inlet of the tap body 11a. It will be seen that the tap body 11a has the tap spindle therein while the tap body lib has the air vent 28 (not shown) while the secondary check valve 17 is located intermediate the tap parts 11a and lib.

Thus it will be apparent from the teaching of this invention that the configuration of independent check valves mounted within a tap housing having a vacuum breaker device addresses the problems previously described and allows the valve assembly of the invention to be used in a wide variety of fluid flow control applications requiring vacuum break and back flow prevention.