Technical field

This invention relates to a fluid flow regulator. The invention has particular but not exclusive application to a fluid flow regulator for regulating the quantity of fluid flowing from a tap, valve or the like. The invention also has particular application to a tap, valve or the like incorporating a flow regulator according to the invention. The invention has particular application for use with domestic water taps.

Background of Invention

For a given fluid pipeline pressure, the flow from a tap is simply a function of the extent to which the tap or valve is opened. As many regions in the world increasingly face water shortage, it is desirable to ensure that flow rates from water reticulation systems are regulated. US patents 6571831 and 4000857 and German patent applications DE 4041 116 A1 and

DE-OS 21 31 117 illustrate flow regulators in which the fluid flowing from a tap or faucet is regulated by varying the total cross-sectional area of the fluid flow path, the area decreasing as supply line pressure increases. In the above patent documents this is achieved by using an elasticised flow restrictor which expands under increasing pressure to restrict flow passages.

Summary of Invention

The present invention aims to provide an alternative to known fluid flow regulators. This invention in one aspect resides broadly in a method of regulating the fluid flow in a tap or valve including:- causing fluid to flow in a fluid flow path through a housing member having a substantially cylindrical inner wall and housing a flow restrictor member having a substantially cylindrical outer wall and being axially moveable within the housing member and dimensioned to provide a substantially annular control passage between the outer wall of the flow restrictor member and the inner wall of the housing member; sealing the control passage between the housing member and the flow restrictor member by a seal slidingly engageable to prevent fluid flow in the control passage past the seal, and biasing the flow restrictor member against the force exerted thereon by the pressure of fluid flowing thereagainst whereby the cross-sectional area of the fluid flow path varies in accordance with the axial position of the flow restrictor member within the housing member.

In another aspect this invention resides broadly in a fluid flow regulator for a tap or valve, the regulator having a fluid flow path therethrough, and including:- a housing member through which fluid flows having a substantially cylindrical inner wall; a flow restrictor member having a substantially cylindrical outer wall and being axially moveable within the housing member and dimensioned to provide a substantially annular control

passage between the outer wall of the flow restrictor member and the inner wall of the housing member; sealing means between the housing member and the flow restrictor member and being slidingly engageable to prevent fluid flow in the control passage past the sealing means, and biasing means which bias the flow restrictor member against the force exerted thereon by the pressure of fluid flowing thereagainst; the cross-sectional area of the fluid flow path varying in accordance with the axial position of the flow restrictor member within the housing member.

It is also preferred that the housing member and the flow restrictor member are cylindrical.

It is also preferred that the housing member is a substantially hollow cylinder open at the inlet end and substantially closed at the outlet end, the substantially closed outlet end having an outlet passage therethrough.

In a first embodiment it is preferred that the flow restrictor member has at least one axially extending passage therethrough and at least one substantially radial passage through the wall thereof, and that the tap or valve flow is through the at least one axially extending passage alone, or through said passage and the at least one radial passage, depending on the axial position of the flow restrictor member within the housing member. The at least one substantially radial passage can extend axially whereby the effective cross sectional area through which fluid flows to enter the axially extending passage varies in accordance with the position of the flow restrictor member within the cylindrical housing, the sealing means variably sealing off the control passage in accordance with the position. However it is preferred that the flow restrictor member has a plurality of axially spaced substantially radial passages through the wall thereof. It is also preferred that the flow restrictor member is a cylinder substantially closed at the inlet end, the substantially closed inlet end having the at least one axially extending passage therethrough. It is also preferred that the sealing means is a seal seated in a first annular recess in the inner surface of the housing member.

In a second embodiment it is preferred that the flow restrictor member includes at least one axially extending passage therethrough and the housing member includes at least one substantially axially extending groove along the inner wall thereof, and the tap or valve flow is through the at least one axially extending passage alone, or through said passage and the at least one axially extending groove, depending on the axial position of the flow restrictor member within the housing member. It is also preferred that the housing member has a plurality of axially extending grooves for providing fluid communication with the control passage at axially spaced locations along the inner wall. Suitably, the axially extending grooves are circumferentially spaced grooves in the inner wall, the grooves being of variable length. It is also preferred that the flow restrictor member is a cylinder substantially closed at the inlet end, the substantially closed inlet end having the at least one axially extending passage therethrough. It is also preferred that the sealing means is at least one seal seated in a respective annular recess in the outer surface of the flow restrictor member.

Alternative arrangements will be apparent. For example there could be more than one seal to better stabilise the flow restrictor member. Moreover the seals could be seated in annular recesses in the inner wall of the housing member and the circumferentially spaced grooves be formed in the outer surface of the flow restrictor member. In both embodiments it is preferred that the biasing means is at least one compression spring bearing against the substantially closed outlet end of the housing member and the substantially closed inlet end of the flow restrictor member. The biasing means could comprise more than a single compression spring. It is also preferred that the compression spring is seated in annular recesses in the substantially closed outlet end of the housing member and in the flow restrictor member. The flow restrictor member can be substantially open at the outlet end as illustrated in the second embodiment. As illustrated in the first embodiment, the flow restrictor member can be substantially closed at the outlet end, the substantially closed outlet end having the at least one axially extending passage therethrough and having an axially extending annular recess for housing and seating the compression spring. In the first embodiment there may be only one substantially radial passage at each axially spaced position, although it is preferred that there is a plurality of axially spaced substantially radial passages at least one of a plurality of axially spaced positions. The plurality of axially spaced substantially radial passages through the wall of the flow restrictor member could be inclined to the axis and pass from the wall to the substantially closed outlet end thereof, although in the preferred embodiment illustrated, the axially spaced substantially radial passages connect with the axially extending annular recess.

In the second embodiment it is preferred that the compression spring is seated in seats in the substantially closed outlet end of the housing member and in the flow restrictor member. The biasing means could comprise more than a single compression spring. It is also preferred that the flow restrictor member is substantially open at the outlet end, the substantially closed inlet end having the at least one axially extending passage therethrough and having a seat for seating the compression spring.

In both embodiments it is preferred that the fluid flow regulator includes stop means to limit movement of the flow restrictor member away from the substantially closed outlet end of the housing member. The stop means could take various forms. It could for example be a threaded washer attached to the open inlet end of the housing member. However it is preferred that the stop means is a circlip seated in an annular recess in the inner surface of the housing member. It is preferred that the fluid flow regulator includes fixing means for fixing the regulator relative to the tap or valve. It is preferred that the fixing means is a screw thread at the open inlet end of the housing member for attaching the regulator to the tap or valve outlet. Alternatively, the fixing means can be a stepped shoulder on the outer surface of the housing member for seating the regulator within the tap or valve.

In another aspect this invention resides broadly in a tap or valve including a fluid flow regulator as defined above.

Description of Drawings

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate two preferred embodiments of the invention, wherein in relation to the first embodiment:- FIG 1 is a cross sectional elevation of a housing member;

FIG 2 is a cross sectional elevation of a flow restrictor member;

FIG 3 is a cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned within the housing member;

FIG 4 is a schematic cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned in the housing member under conditions of relatively low fluid pressure to produce a maximum fluid flow passage;

FIG 5 is a schematic cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned in the housing member under conditions of medium fluid pressure to produce a medium fluid flow passage, and FIG 6 is a schematic cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned in the housing member under conditions of relatively high fluid pressure to produce a minimal size fluid flow passage.

In relation to the second embodiment:-

FIG 7 is a cross sectional elevation of a housing member; FIG 8 is a cross sectional elevation of a flow restrictor member;

FIG 9 is a cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned within the housing member;

FIG 10 is a schematic cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned in the housing member under conditions of relatively low fluid pressure to produce a maximum fluid flow passage;

FIG 11 is a schematic cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned in the housing member under conditions of medium fluid pressure to produce a medium fluid flow passage, and

FIG 12 is a schematic cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned in the housing member under conditions of relatively high fluid pressure to produce a minimal size fluid flow passage.

In relation to further embodiments:-

FIG 13 is a cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned within the housing member in a third embodiment; FIG 14 is a cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned within the housing member in a fourth embodiment, and

FIG 15 is a cross sectional elevation of the fluid flow regulator showing the flow restrictor member positioned within the housing member in a fifth embodiment.

Description of Preferred Embodiment of Invention

Turning to FIGS 1 , 2 and 3 which illustrate a first preferred embodiment of the present invention, the fluid flow regulator 30 (see FIG 3) for a tap or valve is seen to have a cylindrical housing member 10 through which fluid flows and a cylindrical flow restrictor member 21 which is axially moveable within housing member 10 as seen in FIG 3.

Housing member 10 is a substantially hollow cylinder 11 made from brass or other suitable material open at the inlet end 12 and substantially closed at the outlet end 13 which has an outlet passage 14 therethrough.

Flow restrictor member 21 is a cylinder made from brass or other suitable material and is substantially closed at the inlet end 23 which has an axially extending passage 25 therethrough.

In the preferred embodiment illustrated flow restrictor member 21 is substantially closed at the outlet end 24 through which axially extending passage 25 passes. Outlet end 24 also has an axially extending annular recess 28 for housing and seating a compression spring 33 (as seen in dotted outline in FIGS 3-6) and which acts as biasing means to bias the flow restrictor member 21 against the force exerted thereon by the pressure of fluid flowing thereagainst. Alternatively, as best seen in FIG 13, the outlet end 24 of flow restrictor member 21 may be substantially closed in an arrangement similar to that subsequently described with more particularity with reference to the second embodiment illustrated in FIGS 7-12.

In arrangements not shown, there may of course be more than two sets of radial passages. There need not be more than one radial passage at each axial position, or as indicated previously, there need not be more than one axially spaced radial passage - rather, a single axially extending radial passage can be utilised. There could also be one or more arrays of radial passages in a spiral pattern.

Flow restrictor member 21 is dimensioned to provide a control passage 29 between the outer wall 22 of flow restrictor member 21 and the inner wall 17 of housing member 10. In the illustrated embodiment, flow restrictor member 21 has an axially extending passage 25 therethrough, and two sets of substantially radial passages 26a, 26b 26n and 27a, 27b 27n at two axially spaced locations 26 and 27.

An annular recess 15 is formed in the inner surface 17 of housing member 10 and holds sealing means in the form of an O-ring seal 31 which effects a seal between housing member 10 and flow restrictor member 21 to prevent fluid flow in control passage 29 past seal 31.

The tap or valve flow is thus seen to be controlled by flow restrictor member 21 so as to be either through axially extending passage 25 alone, or through passage 25 and the set of radial passages 26a, 26b 26n at axial location 26, or through passage 25 and the both sets of radial passages 26a, 26b 26n and 27a, 27b 27n at both axial location 26 and 27. Which of these alternatives constitute the tap or valve flow path pattern is determined by the axial position of flow restrictor member 21 within housing member 10.

This is turn depends (as will be described subsequently) on the pressure of the fluid flowing against the inlet end 23 of flow restrictor member 21 which exerts a force thereon which acts against an opposing force on flow restrictor member 21 exerted by compression spring 33

which bears against the substantially closed outlet end 13 of housing member 10 where it is seated in annular recess 18, and the substantially closed inlet end 23 of flow restrictor member 21 where it seats and is housed in axially extending annular recess 28.

Flow restrictor member 21 is prevented from travelling to the full extent of expansion of compression spring 33 by stop means in the form of a circlip 32 seated in a second annular recess 16 in inner surface 17 of housing member 10 located towards the inlet. Circlip 32 limits movement of flow restrictor member 21 away from the outlet end 13 of housing member 10.

Flow regulator 30 can be attached to the outlet spout of a tap by fixing means in the form of screw thread (not shown) at position 19 at the open end 12 of housing member 10. Alternatively, flow regulator 30 can be seated within the tap or valve by fixing means in the form of stepped shoulder 20 in the outer surface of housing member 10 which engages with a complementary seat in the tap or valve (not shown). In order to attach an aerator or the like, a screw thread (not shown) may be provided at position 34 at the outlet end 13 of housing member 10. Turning now to FIG 4, when the inlet end of flow restrictor member 21 is acted on by a low fluid pressure acting in one direction against the bias of compression spring 33 acting in the opposite direction, flow restrictor member 21 adopts the position shown. This is referred to as the static position of the flow restrictor member. As seen by the block arrows, with flow restrictor member 21 in this position, fluid can flow through the open end of housing member 10, through the central passage in flow restrictor member 21 and out of the flow regulator though the central passage in the outlet end of housing member 10. Fluid can also flow through the open inlet end of housing member 10, through the control passage 29 between the housing member 10 and the flow restrictor member 21, through both sets of axially spaced radial passages in flow restrictor member 21 , through the annular recess in flow restrictor member 21 which also houses the compression spring and out of the flow regulator though the central passage in the outlet end of housing member 10.

When the inlet end of flow restrictor member 21 is acted on by a medium or intermediate fluid pressure acting in one direction against the bias of compression spring 33 acting in the opposite direction, flow restrictor member 21 moves against the spring and adopts the position seen in FIG 5. This is referred to as an intermediate position of the flow restrictor member. Again as seen by the block arrows, with flow restrictor member 21 in this position, fluid can flow through the inlet end of housing member 10, through the central passage in flow restrictor member 21 and out of the flow regulator though the central passage in the outlet end of housing member 10. Fluid can also flow through the inlet end of housing member 10, through the control passage 29 between the housing member 10 and the flow restrictor member 21, but through only the uppermost of the sets of axially spaced radial passages in flow restrictor member 21, through the annular recess in flow restrictor member 21 which also houses the compression spring and out of the flow regulator though the central passage in the outlet end of housing member 10. In this position, the lowermost of the sets of axially spaced radial passages is blocked off by O ring 31 ,

thus controlling the volume of fluid that flows through the flow regulator by restricting the total cross-sectional area of the fluid flow passage.

Finally with reference to FIG 6, it can be seen that when the inlet end of flow restrictor member 21 is acted on by a high fluid pressure acting in one direction against the bias of compression spring 33 acting in the opposite direction, flow restrictor member 21 moves even further against the spring and adopts the final position seen in FIG 6. This is referred to as the stop position of the flow restrictor member. Again as seen by the block arrows, with flow restrictor member 21 in this position, fluid can only flow through the inlet end of housing member 10, through the central passage in flow restrictor member 21 and out of the flow regulator though the central passage in the outlet end of housing member 10. Fluid can flow through the inlet end of housing member 10 and into but not through the control passage 29 between the housing member 10 and the flow restrictor member 21, because O ring 31 prevents any fluid flowing through either set of axially spaced radial passages in flow restrictor member 21 , thus further restricting the total cross- sectional area of the fluid flow passage to control the volume of fluid flowing through the flow regulator.

Turning to FIGS 7, 8 and 9 which illustrate a second preferred embodiment of the present invention, the fluid flow regulator 130 (see FIG 9) for a tap or valve is seen to have a cylindrical housing member 110 through which fluid flows and a cylindrical flow restrictor member 121 which is axially moveable within housing member 110 as seen in FIG 9. Housing member 110 (see FIG 7) is a substantially hollow cylinder 111 made from brass or other suitable material open at the inlet end 112 and substantially closed at the outlet end 113 which has an outlet passage 114 therethrough.

Flow restrictor member 121 (see FIG 8) is a cylinder made from brass or other suitable material and is substantially closed at the inlet end 123 which has an axially extending passage 125 therethrough. In the preferred embodiment illustrated flow restrictor member 121 is substantially open at the outlet end 124 and inlet end 123 provides a seat 136 for seating a compression spring 133 (as seen in dotted outline in FIGS 9-12) and which acts as biasing means to bias the flow restrictor member 121 against the force exerted thereon by the pressure of fluid flowing thereagainst. Flow restrictor member 121 is dimensioned to provide a control passage 129 between the outer wall 122 of flow restrictor member 121 and the inner wall 117 of housing member 110. In the illustrated embodiment, flow restrictor member 121 has an axially extending passage 125 therethrough and housing member 110 has a plurality of axially extending peripherally spaced grooves 134, 135 on the inner wall 117. It will be understood that although only two grooves appear in FIGS 7 and 9 which are cross-sectional elevations, there can and in practice preferably will be more than only two such grooves spaced circumferentially about inner wall 117. Typically there could be four or six grooves each of different axial length. Flow restrictor member 121 and housing member 110 are dimisnsioned to provide an annular passage 129 between the inner wall

134,135 constitute axially extending passages in communication with annular passage 129. As can be seen in FIGS 7 and 9, grooves 134,135 are of variable length.

An annular recess 137 is formed in the outer surface 122 of flow restrictor member 121 and holds sealing means in the form of an O-ring seal 131 which effects a seal between housing member 110 and flow restrictor member 121 to block fluid flow in control passage 129 at seal 131 when the seal is below the end of passages 134, 135.

The tap or valve flow is thus seen to be controlled by flow restrictor member 121 so as to be either through axially extending passage 125 alone, or through passage 125 and groove 135 and/or groove 134. Which of these alternatives constitute the tap or valve flow path pattern is determined by the axial position of flow restrictor member 121 within housing member 110.

This is turn depends (as will be described subsequently) on the pressure of the fluid flowing against the inlet end 123 of flow restrictor member 121 which exerts a force thereon which acts against an opposing force on flow restrictor member 121 exerted by compression spring 133 which bears against the substantially closed outlet end 113 of housing member 110 where it is seated in recess 118, and the substantially closed inlet end 123 of flow restrictor member 121 where it seats on seat 136.

Flow restrictor member 121 is prevented from travelling to the full extent of expansion of compression spring 133 by stop means in the form of a circlip 132 seated in an annular recess 116 in inner surface 117 of housing member 110 located towards the inlet. Circlip 132 limits movement of flow restrictor member 121 away from the outlet end 113 of housing member 110.

It will be appreciated that stop means other than a circiip can be used. For example, in a manner not illustrated, annular recess 116 could house a retaining lug or flange at the base of an inverted hollow truncated cone made of pliable plastic material, the top end of which bears against and stops the inlet end of flow restrictor member 121. The Cone stop means is soft enough to be compressed and pushed in so that the flange sits in annular recess 116, but resilient enough to act as a stop.

Flow regulator 130 can be attached to the outlet spout of a tap by fixing means in the form of screw thread (not shown) at position 119 at the open end 112 of housing member 110. Alternatively, flow regulator 130 can be seated within the tap or valve by fixing means in the form of stepped shoulder 120 in the outer surface of housing member 110 which engages with a complementary seat in the tap or valve (not shown). In order to attach an aerator or the like, a screw thread (not shown) may be provided at position 138 at the outlet end 113 of housing member 110.

Turning now to FIG 10, which shows the position of flow restrictor 121 with a low fluid pressure (typically of about 150 kPa) acting on the end of the restrictor, when the inlet end of flow restrictor member 121 is acted on by a low fluid pressure acting in one direction against the bias of compression spring 133 acting in the opposite direction, flow restrictor member 121 adopts the position shown. This is referred to as the static position of the flow restrictor member. As seen by the block arrows, with flow restrictor member 121 in this position, fluid can flow through the open inlet end of housing member 110, through the central passage in flow restrictor member 121

and out of the flow regulator though the central passage in the outlet end of housing member 110. Fluid can also flow through the open inlet end of housing member 110, through the control passage 129 between the housing member 110 and the flow restrictor member 121 , through both grooves 134, 135 in housing member 110, and out of the flow regulator though the central passage 114 in the outlet end of housing member 110.

When the inlet end of flow restrictor member 121 is acted on by a medium or intermediate fluid pressure acting in one direction against the bias of compression spring 133 acting in the opposite direction, flow restrictor member 121 moves against the spring and adopts the position seen in FIG 11 which shows the position of flow restrictor 121 with a medium fluid pressure (typically of about 250 kPa) acting on the end of the restrictor. This is referred to as an intermediate position of the flow restrictor member. Again as seen by the block arrows, with flow restrictor member 121 in this position, fluid can flow through the inlet end of housing member 110, through the central passage in flow restrictor member 121 and out of the flow regulator though the central passage in the outlet end of housing member 110. Fluid can also flow through the inlet end of housing member 110, through the control passage 129 between the housing member 110 and the flow restrictor member 121 , but through only groove 134 and out of the flow regulator though the central passage 114 in the outlet end of housing member 110. In this position only groove 134 acts as a grooved fluid passageway and is the only groove not blocked off by O ring 131 , thus controlling the volume of fluid that flows through the flow regulator by restricting the total cross-sectional area of the fluid flow passage.

Finally with reference to FIG 12, which shows the position of flow restrictor 121 with a high fluid pressure (typically of about 350 kPa or more) acting on the end of the restrictor, it can be seen that when the inlet end of flow restrictor member 121 is acted on by a high fluid pressure acting in one direction against the bias of compression spring 133 acting in the opposite direction, flow restrictor member 121 moves even further against the spring and adopts the final position seen in FIG 12. This is referred to as the stop position of the flow restrictor member. Again as seen by the block arrows, with flow restrictor member 121 in this position, fluid can only flow through the inlet end of housing member 110, through the central passage 114 in flow restrictor member 121 and out of the flow regulator though the central passage in the outlet end of housing member 110. Fluid can flow through the inlet end of housing member 110 and into but not through the control passage 129 between the housing member 110 and the flow restrictor member 121 , because O ring 131 blocks any fluid flowing past it and because the lower axial position of flow restrictor member 121 means that no groove in the housing member 110 can act as a fluid passageway, thus further restricting the total cross-sectional area of the fluid flow passage to control the volume of fluid flowing through the flow regulator.

Alternative arrangements to those described in the two embodiment above will be apparent. As seen in FIG 14 for example, two seals may be seated on the flow restrictor member to provide better stability during movement of the flow restrictor member within the housing member. Furthermore, as seen in FIG 15, the positioning of seals and the circumferentially spaced grooves can be reversed from that described and illustrated with reference to FIGS 7 to

12. As seen in FIG 15, the seals can be seated in annular recesses in the inner wall of the housing member with the circumferentially spaced grooves formed in the outer surface of the flow restrictor member.

It will be appreciated that for a given tap or valve setting, the flow will increase as water pressure increases. For a given tap or valve setting this effect can be offset by decreasing the size of the flow passage. The extent to which this increase in flow can be offset can be varied by varying the strength of the compression spring. For a given water pressure, the adjusted flow will be greater if the spring is stronger and vice versa.

The flow regulator of the present invention is thus seen to restrict the maximum rate of flow from a tap or valve and can ensure that the flow rate is kept within specified limits over a set range of fluid pressures in the supply line at the tap.

It will of course be realised that whilst the above has been given by way of an illustrative example of this invention, all such and other modifications and variations hereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is herein set forth.