RELIEF VALVE

TECHNICAL FIELD

A relief valve for use in controlling/regulating the operating fluid of a circuit is disclosed. Whilst the valve is primarily described for use in controlling/regulating the pressure in a water filter system connected to a mains water supply, it should be appreciated that its application is not so limited.

BACKGROUND ART

It is known that the water pressure in water filter systems connected to mains water can fluctuate during the day. When the water pressure in a water filter system rises above a manufacturer's recommended maximum pressure, filter housings can fracture and system fittings can fail.

Water filter systems also use push-in quick-fit connection fittings with plastic or soft metal tubes in both inch and metric sizes. Heretofore, pressure relief vales have not been available for use in such water filter systems.

SUMMARY OF THE DISCLOSURE hi one aspect there is provided a relief valve comprising:

- a housing having an inlet, a chamber and an outlet;

- a valve member disposed within the chamber and adapted up to a given fluid pressure to close off fluid communication between the inlet and the outlet, but to move when the fluid pressure exceeds the given pressure, thereby allowing fluid to flow from the inlet to the outlet.

Such a valve can be adapted to have particular application in a mains water filter system and can prevent leakage of an operating fluid (eg. water) by relieving any sudden pressure increases in the operating fluid. In this regard, it may be positioned at or as part of on offtake of such a system.

The valve member can be urged by a biasing element to close off fluid communication from the inlet to the chamber. For example, the biasing element can be a spring (eg. a helical spring) that extends between the valve member and an opposing wall of the chamber, and that is adapted to be compressed to allow valve member movement at a fluid pressure at the inlet that exceeds the given pressure. In this regard, the relief valve can be adapted to open when the operating fluid acting on the valve

member is introduced with a pressure greater than the spring force of the spring that forces the valve member into a closed configuration.

In one form, one end of the spring can be retained on a stem of the valve member that projects towards the chamber opposing wall, and the other end of the spring can be retained on a skirt surrounding the outlet at and projecting from the chamber opposing wall.

In one form the valve member comprises a valve seal that is arranged, in the closed off configuration, for sealing against a chamber wall where the inlet enters the chamber. The valve member may further comprise a protruding part around which the valve seal can be arranged, with the protruding part in the closed off configuration being received in a corresponding recess defined in the chamber wall where the inlet enters the chamber. This configuration can better seal and close off the inlet.

In one form the housing has a two-part construction, with a first part comprising the inlet, and a second part comprising the outlet. The parts can be configured such that, when coupled together, the chamber is defined therewithin. For example, the second housing part can be screw-threadingly mounted within an open end of the first housing part. This can allow for interchange of parts and coupling mechanisms.

Either or both of the inlet and outlet may be adapted to have push-in fittings connected thereto. For example, when the inlet comprises a stem construction thereat, the construction may have an outer diameter adapted to receive a standard push-in connection fitting. By way of further example, when the outlet comprises an open, outwardly facing recess, this recess may have a series of progressively decreasing diameter sections for receiving a standard quick- fit half cartridge therein. In a second aspect there is provided a mains water filter system relief valve that is adapted to open when system water pressure exceeds a predetermined value.

The valve of the second aspect can otherwise be defined as in the first aspect.

BRIEF DESCRIPTION OF THE DRAWING Notwithstanding any other forms which may fall within the scope of the relief valve as disclosed in the Summary, a specific embodiment of a relief valve will now be

described, by way of example only with reference to Figure 1 which shows a cross- sectional view of a relief valve embodiment.

DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT

Referring to Figure 1, a cross sectional view is shown of a relief valve that is suitable for use in controlling/regulating the pressure in a water filter system connected to a mains water supply.

The relief valve comprises a body in the form of a two-part housing (1 & 2) is shown. The housing part (2) is screw-threadingly mounted within an open end of the housing part (1) (as shown), and is sealed therein by O-ring (2A). The housing is provided with an inlet port (3) and a stepped outlet port (4) of increasing diameter. Operating fluid (eg. water) is introduced through the inlet port (3) and the fluid is discharged at a given (eg. prescribed) pressure through the outlet port (4).

The operating fluid that is introduced at inlet port (3), and discharged at outlet port (4), flows through chamber (5) formed within and defined by the two-part housing (1 & 2).

A combination valve body (6) and a valve seal (7) are positioned in the chamber (5). The valve body comprises a lobe (6A) that can be located in a hemispherical recess (5A) defined a wall of the chamber (5) located adjacent to the inlet port (3). A compression spring (8) is located as shown to act on the valve body (6) and force the valve seal (7) against the wall of chamber (5), closing the recess (5A) and the associated end of the inlet port (3). This blocks the passage of operating fluid from the inlet port (3) into the chamber (5). At this position the relief valve is closed.

It will be seen that one end of the spring (8) is retained on a stem (6B) of the valve body (6), the stem projecting in use towards a wall (2B) of the housing part (2). The other end of the spring is retained on a projecting skirt (2C) that surrounds the outlet at the wall (2B).

The relief valve opens when the operating fluid is introduced with a pressure greater than the force of the compression spring (8), forcing the valve body (6) and the valve seal (7) to move in the direction of flow of the operating fluid through the valve (ie. away from the chamber wall adjacent to the inlet port (3)).

The diameter (9) of the stem of the inlet port (3) can be sized to suit push-in, quick- fit connection fittings such as John Guest ™ connectors or tees, or the like.

Again, the stepped outlet port (4) with the progressively decreasing diameter sections (10, 11 & 12) can be sized to receive quick-fit half cartridges, such as John Guest ™ half cartridges or the like.

A quick-fit half cartridge (such as John Guest ™ type) provides a rapid means of obtaining a secure push-in connection at the housing part (2). Such a half cartridge can be made up of three components, namely: a collet or gripper, an 'O'-ring and a plastic body with stainless steel teeth, for receipt in section (10, 11). With the half cartridge in position the stainless steel teeth tend to sink (or bite) into the housing. Although the relief valve has been described and illustrated in a particular configuration, it is to be understood that the details of the structure and/or the function may be varied substantially without departing from the overall scope of the relief valve as described and defined herein.

For example the inlet port (3) may also be constructed such that, instead of a stem, a John Guest ™ type (or the like) quick- fit half cartridge can be inserted thereat, and the outlet port (4) may be constructed such that instead of inserting a half cartridge, a stem can constructed to suit a John Guest ™ type quick-fit connector or tee (or the like).

Also, whilst the primary application of the relief valve as described is in the controlling/regulating of water pressure in a water filter system connected to a mains water supply, it should be appreciated that it can be applied in other water-based, liquid- based and potentially even gas-based applications. Also, whilst the valve is typically positioned at or as part of on offtake line in a mains water filter system, it may be reconfigured to be in-line etc.

In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.