WO1999008076A1

WO1999008076A1 - Fluid dispensing device

Info

Publication number: WO1999008076A1
Application number: PCT/AU1998/000622
Authority: WO
Inventors: Brian Rollston
Original assignee: Hennessey, Alan, John
Priority date: 1997-08-07
Filing date: 1998-08-07
Publication date: 1999-02-18

Abstract

A device (10) for dispensing a metered dose of a first fluid (12), such as a cleaning agent, into a second fluid that has a surface that varies in height. The device (10) includes a reservoir (11) for the first fluid (12) and a piston (13) that has a fluid collection means that is relatively movable through an orifice (17) of the reservoir under the influence of a float (14). The float (14) moves in concert with the varying heigh of the surface of the second fluid. When the piston (13) moves upwardly relative to the remainder of the device (10), the fluid collection means collects the cleaning fluid (12). When the piston (13) moves relatively downwardly, the collected cleaning fluid (12) is dispensed from the reservoir (11) and is ready for dispersal as required.

Description

"Fluid dispensing device"

Field of the Invention

The present invention relates to a device for dispensing a metered dose of a first fluid, such as a cleaning fluid, into a second fluid, such as water used to flush a toilet bowl or urinal.

Background of the Invention

Toilet bowls and urinals require regular cleaning if they are to remain hygienic and possess a desirable level of cleanliness. Cleaning agents are often utilised in the cleaning of such devices. While regular treatment with cleaning agents will appropriately clean a toilet bowl or urinal, it can be difficult to retain appropriate standards in the case of public toilets which can be undesirably soiled after just one use.

It is accordingly desirable to provide a device that can automatically dispense chemical cleaning agents into the water flowing through a toilet bowl or urinal on a regular basis. While such devices are known, devices to date have typically either not supplied a precisely metered dose of cleaning agent or have incorporated a large number of moving parts and are hence prone to breakdown.

Summary of the Invention According to a first aspect, the present invention is a device for dispensing a metered dose of a first fluid into a second fluid that has a surface that varies in height, the device including: a reservoir for the first fluid, the reservoir having an orifice disposed proximate a lower end thereof; a piston relatively movable through the orifice and having a first sealing surface, a second sealing surface, and a first fluid collection means separating the first and second sealing surfaces; and a flotation means that can move in concert with the varying height of the second fluid surface; the flotation means being adapted in use to move the piston between at least a first position, where the first sealing surface is sealing the orifice and the first fluid collection means is outside the reservoir, and a second position where the second sealing surface is sealing the orifice and the first fluid collection means can collect the first fluid from inside the reservoir, and then back to the first position to dispense the collected first fluid to outside of the reservoir. The device according to the present invention can incorporate only one moving part, namely the piston moving relative to the reservoir, requires no electrical power and also dispenses a precise quantity of first fluid out of the reservoir in each instance of operation. In a preferred embodiment, the flotation means includes an outwardly extending frusto-conical member having an upper and lower surface. The upper surface of the frusto-conical member is preferably attached to the piston below and adjacent the second sealing surface such that its longitudinal axis is aligned with the longitudinal axis of the piston. On placement of the frusto-conical member downwardly into the second fluid with its longitudinal axis held vertical, it is possible to trap a quantity of air under the lower surface which serves to give the frusto-conical surface buoyancy when the device is in use.

A fluid catchment means is also preferably disposed on the upper surface of the frusto-conical member. The fluid catchment means can be provided by a wall extending upwardly from the upper surface of the frusto- conical member. The upstanding wall can be cylindrical and extend upwardly adjacent an outer edge of the upper surface so forming a catchment means provided by the upper surface of the frusto-conical member and the upstanding cylindrical wall. A fluid outlet means is preferably formed in the wall above and adjacent its connection to the upper surface to allow the fluid to exit the fluid catchment means. The fluid outlet means can include a discontinuous slot extending about some or all of the perimeter of the upstanding wall or a number of orifices regularly spaced around the perimeter of the wall.

An outer surface of the wall comprising the fluid catchment means is preferably adapted to move relatively within a surrounding collar having an inner surface shaped to match the shape of the outer surface of the upstanding wall on the flotation means. When the upstanding wall has a cylindrical outer surface, the inner surface of the collar will also have a cylindrical surface. The collar can comprise a downwardly extending extension of the reservoir. The collar also preferably has a fluid inlet means disposed to allow the second fluid to enter the collar and be caught by the fluid catchment means. If necessary, the collar can also have a fluid outlet means disposed to allow fluid exiting the fluid outlet means of the upstanding wall to also exit through the collar when the piston is in the first position.

Both the fluid inlet means and fluid outlet means of the collar can comprise a discontinuous slot extending about some or all of the perimeter of the collar.

The lower edge of the collar can have a plurality of downwardly extending fingers about its periphery to help disperse the fluid exiting the fluid outlet means of the collar. The fingers can be equally spaced about the periphery. The first and second sealing surfaces are preferably provided by respective cylindrical portions of the piston. The fluid collection means is preferably provided by a central post of smaller diameter than the respective cylindrical portions and extending between them, with the smaller diameter of the central post defining the piston between the respective cylindrical portions and the distance between the cylindrical portions setting the volume of the first fluid collected by the first fluid collection means when the piston is in the second position. At or adjacent the free end of the cylindrical portion distal the flotation means, the piston can have a boss. The boss serves to limit the travel of the piston through the orifice in the lower end of the reservoir. The piston can also be comprised of two or more interconnectable parts to allow ready assembly or disassembly of the piston as required.

In one embodiment, the size of the collection means can be adjusted by attaching clips of differing thicknesses around the central post so as to occupy a portion of the volume of the fluid collection means and so control the volume of first fluid collected and dispensed by the device. Where the central post is cylindrical, the clip can be a C-clip.

The reservoir can include a cylindrical chamber with its lower end comprising a substantially flat base. The orifice is presently formed at the centre of the base. The orifice can have about its periphery a wall extending upwardly therefrom and having an inner surface adapted to seal with the first and second sealing surfaces of the piston as it moves relative thereto. The height of the wall about the orifice is preferably greater than the length of the fluid collection means of the piston. The reservoir can comprise a sealed chamber. For example, the chamber can be sealed with a threaded or push-on closure after being filled with the first fluid. In a still further embodiment, first fluid can be supplied to the reservoir by a pipe from a fluid storage area disposed some distance from the device.

In one embodiment of the invention, the device can be positioned within an outer chamber. The outer chamber can engage the outer surface of the device and can contain the second fluid. In this embodiment, the outer chamber preferably has an inlet disposed separated from a lower end thereof to allow the second fluid to enter the chamber. The chamber also has an outlet, preferably positioned at its lowest end, to allow the second fluid to exit the chamber. To allow air to escape the chamber on entry of the second fluid through its inlet, at least one orifice is preferably provided in the chamber wall adjacent its upper end.

In another embodiment of the present invention, the flotation means can comprise a float mounted on at least one float arm. The float can be a hollow air-filled float or can be comprised of a floatable material such as foam. The at least one float arm can extend outwardly from a cam assembly that is adapted to rotate about a pivot point. The float is preferably attached to the float arms by means of slots in the float that form an interference fit with the float arms. By sliding the float along the arms to different positions it is possible to vary the swept value of the float. The swept value increases on sliding of the float away from the pivot point and decreases on sliding of the float towards the pivot point. This feature, in this embodiment, allows the dispenser to compensate for different shapes of cistern which can produce different rates of change of water level in the cistern during a flush and also lead to different overall changes in the vertical height of the water between the beginning and end of a flush. The float can be made in a variety of shapes including a sphere, a cylinder or an ellipsoid. If desired, the float can be made in the shape of an animal, including a marine animal. The interference slots in the float for the float arms can also be offset from an axis of the float.

The cam assembly in the embodiment of the invention having a hollow float can have two cams located at pre-set angles radiating from the pivot point of the assembly. Both sets of cams can be partially split adjacent their ends distal the pivot point to form two sets of fingers that are a slightly greater distance apart than the diameter of complementary cam drive slots on the piston distal the first and second sealing surfaces. In operation, the fingers are adapted to engage with the cam drive slots on the piston and so move the piston relative to the dispenser as is described in more detail below.

The cam assembly is preferably supported between two legs that extend downwardly from the collar of the dispenser. The inside of each leg preferably has a locating lug that serve to locate the cam assembly in the desired position and allow the cam assembly to freely rotate in a vertical plane relative to the legs.

In this further embodiment of the invention, the piston can have two fluid collection means for collecting first fluid from the reservoir. Below the fluid collection means, the piston can have a plurality of inlet ports that are in fluid communication with a bore that extends through the piston to an outlet at its end distal the fluid collection means.

The device according to the various embodiments of the present invention can be fabricated from any suitable material, including sheet metal or a polymeric material such as poly(vinyl chloride) (PVC) or polymethylmethacrylate (PMMA).

The first fluid can be a cleaning and/or odour-neutralising fluid. The second fluid can be water and, preferably, water used to flush toilet bowls and urinals. In one embodiment, the device can be mounted in a cistern of a toilet and is preferably adapted to only dispense the first fluid when the toilet is flushed. In another embodiment, the device can be mounted on or in a pipe carrying flushing water to the toilet or urinal.

In another embodiment, the device according to the present invention can be used to dispense a metered dose of nutrients or other desired additives to a hydroponic system or a metered dose of biocide to a water cooled air conditioning system. Brief Description of the Drawings

By way of example only, preferred embodiments of the invention are now described with reference to the accompanying drawings, in which:

Fig. 1 is a vertical cross-sectional view of one embodiment of a dispensing device according to the present invention;

Fig. la depicts enlarged plan and side elevational views of a C-clip for use with the device depicted in Fig. 1; Fig. 2 is a vertical cross-sectional view of a second embodiment of a device according to the present invention with the piston in its lower position;

Fig. 3 is a vertical cross-sectional view of the second embodiment with the piston depicted in its upper position;

Fig. 4 is a vertical cross-sectional view of a third embodiment of a device according to the present invention with its piston in its upper position;

Fig. 5 is a perspective view of the cam assembly of the dispenser depicted in Fig. 4; and

Fig. 6 provides two vertical sectional views of the dispenser depicted in Fig. 4 with its piston in a lower position to that depicted in Fig. 4. Preferred Mode of Carrying out the Invention

A first embodiment of a device for dispensing a metered dose of a cleaning and odour control fluid into the water in a toilet cistern on flushing of the toilet is depicted generally as 10 in Fig. 1.

The plastic dispenser 10 comprises a sealed cylindrical reservoir 11 for the cleaning fluid 12, a piston 13 having a float 14, and a cylindrical collar 15 depending from the circular lower edge 16 of the reservoir 11. The piston 13 is movable relative to the reservoir 11 and the collar 15 through the circular orifice 17 formed in the base 18 of the reservoir 11. The periphery of the orifice 17 is surrounded by a cylindrical wall 19 extending upwardly from the base 18. The piston 13 has a first cylindrical portion 21 at one end having a first cylindrical sealing surface 22. The piston also has a second cylindrical portion 23 having a second sealing surface 24 separated from the first cylindrical portion by a central post 25. The length of the central post 25 and the difference in its diameter to that of the first and second cylindrical portions 21,23 defines the parameters of a fluid collection area 20 and sets the maximum volume of the fluid 12 collected from the reservoir 11 in each instance of operation of the device 10. The volume of the fluid collection area 20 can be reduced if desired by positioning a C- shaped clip 37, depicted in Fig. la, about the central post 25.

At the end of the piston 13 distal the first cylindrical portion 21 and within the collar 15 is the float 14. The float 14 comprises a frusto-conical portion 26 having a cylindrical wall 27 extending upwardly from its outer edge. The frusto-conical portion 26 and the cylindrical wall 27 define a catchment 30 for water 34. A discontinuous slot 28 that allows water 34 to exit the catchment 30 extends about the circumference of the wall 27 adjacent the outer edge of the frusto-conical portion 26. The undersurface 35 of the frusto-conical portion 26 on placement of the float 14 directly into water traps a pocket of air that serves to provide the necessary buoyancy required by the float 14 when the dispenser 10 is in use as described below.

Adjacent its connection to the reservoir 11, a discontinuous slot 29 also extends about the circumference of the collar 15. A further discontinuous slot 31 distal the slot 29 is also provided about the circumference of the collar 15 and is positioned to allow water exiting the catchment 30 to also exit through the collar 15 when the slots 28 and 31 are longitudinally aligned.

Disposed below the discontinuous slot 31 on dispenser 10 is an abutment 32 that serves as a piston stop and so limits the travel of the float 14 relative to the reservoir 11 and collar 15. Below the abutment 32 and about the circumference of the collar 15, a plurality of equally spaced fingers 33 are disposed that help to disperse water passing thereover as is explained more fully below.

In use, the dispenser 10 is placed within a toilet cistern at a position such that the rise and fall of water on flushing of the cistern will move the float 14 upwardly and downwardly relative to the reservoir 11. In some cisterns, the fall of water within the cistern can be little as 45mm. The depicted embodiment of the device is designed to operate in cisterns having such small changes of water level on flushing, with the collar being accordingly about 45mm in length. It will be readily appreciated by persons skilled in the art of the invention that the dispenser 10 will operate in cisterns having far greater changes in water level. It will also be appreciated by persons skilled in the art that the depicted dispenser 10 could be readily modified to operate in cisterns having a water level change of less than 45mm if required.

In Fig. 1, the dispenser 10 is depicted as if the cistern has just been flushed and is emptying of water. Accordingly, the dispenser 10 is depicted with the piston 13 at its lowest position, with the float 14 against abutment 32 and where cleaning fluid 12 has just been dispensed into the water 34 stored in the catchment 30 on the float 14. At times when the toilet is not being used and the cistern has filled with the water, the piston 13 will have risen, due to the float 14. to its highest position relative to the reservoir 10. While the cistern is full with water and unflushed. the piston 13 remains at its furthermost upward extent. At this time, the central post 25 extends into the reservoir 11 and the orifice 17 is sealed by the second sealing surface 24. With the cistern full, water will have also entered through the slot 29 and filled the catchment 30 on the upper surface of the float 14. Because of the air trapped below the float 14 and that the outer surface of the cylindrical wall 27 does not form a perfect seal with the surrounding inner surface of the collar 15, the float retains the piston 13 in its furthermost upward extent despite the weight of the water in the full catchment 30.

On flushing of the cistern, the water level in the cistern immediately begins to fall. As a result, water stops entering the dispenser through slot 29, the float 14 begins to drop leading to the piston 13 also beginning to fall so that the central post 25 of the piston enters the area of the orifice 17 surrounded by the cylindrical wall 19. Continued fall of the water in the cistern results in the second sealing surface exiting the orifice 17 so allowing the cleaning fluid 12 trapped in the fluid collection area 20 to fall and disperse into the water 34. This pre-dispersal of the cleaning fluid 12 into the water 34 is particularly advantageous as it later increases the rapidity of the dispersion of the fluid 12 into the water in the cistern. Also, by this time, the first sealing surface 22 has sealed the orifice 17 so preventing any further cleaning fluid 12 exiting the reservoir 11 than that dispensed by the fluid collection area 20.

Continued fall of the water in the cistern results in the float 14 striking the abutment 32 and the slots 28 and 29 coming into longitudinal alignment, ie. the piston 13 has returned to the position depicted in Fig. 1. At this point the water 34 having the dispersed cleaning fluid 12 exits the catchment 30, runs over the fingers 33, enters the water in the cistern and then is flushed into the toilet. The fingers serve to further disperse the water 34 containing the fluid 12 throughout the remaining the water in the cistern. Also, because the water 34 with dispersed cleaning fluid 12 does not enter the cistern water until the flush is well underway, it ensures that a significant proportion of the cleaning fluid remains in the water remaining in the toilet bowl at the end of the flush so maximising the time it is in contact with the toilet bowl and hence its cleaning effectiveness. Once the cistern has emptied, it begins to fill with water in the normal manner. The rising level of the water leads to the float 14 again rising so moving the piston 13 upwardly relative to the orifice 17. By the time the cistern has filled, the fluid collection area 20 has again entered the reservoir 11 and water in the cistern is also able to enter through slot 29 and fill the catchment 30 on the upper surface of the float 14. The dispenser 10 is then again ready to dispense a metered dose of the cleaning fluid 12 as described above.

A second embodiment of a dispensing device according to the present invention is generally depicted as 40 in Figs. 2 and 3, with like features numbered in accordance with the numbering of features utilised in respect of Fig. 1.

In this embodiment, the dispensing device 40 is housed within an outer chamber 41. The chamber 41 has an upper cylindrical portion 42 and a lower frusto-conical portion 43 defining therein a water holding area 55.

Disposed in the wall of the frusto-conical portion 43 is a fluid inlet 44 connected to a feed pipe 49, while at the lower end thereof, there is provided a fluid outlet 45 connected to a drain pipe 51. At its upper end, the outer chamber 41 has a screw thread 46 adapted to engage with a complementary screw thread 47 on the outer surface of the collar 15 of the dispenser 40. While shown connected to the collar by the complementary screw threads 46,47, it can be readily envisaged that the collar 15 and outer chamber 41 could be formed as an integral unit. Below the complementary screw threads 46,47, the chamber 41 has a small orifice 56 that allows air to escape the chamber 41 as the float 14 is moved upwardly by water entering the water holding area 55 as described below.

Shown also connected by a screw thread to an upper end of the collar 15 is a reservoir 11 having an inlet pipe 48. As in the first depicted embodiment, the dispenser 40 has a centrally located piston 13 having the same features as depicted in Fig. 1. The piston 13 is also connected to a float 14 which in turn has a cylindrical wall 27 around its outer edge defining a water catchment. Disposed at the lower end of the catchment are a plurality of evenly spaced orifices 52 in the cylindrical wall 27 that allow water to exit the catchment when the orifices 52 are below the lower end 53 of the collar 15. The upper end of the piston 13 also has a boss 36 that prevents the piston 13 falling downwardly completely out of the dispenser 40 by abutting the cylindrical wall 19 surrounding the orifice 17 in the lower end of the reservoir 11. As depicted in Fig. 2, the boss 36 can be adapted to allow travel of the piston 13 sufficiently downwardly to allow the orifices 52 to clear the lower end of the collar 15 but no further. In this embodiment, the piston 13 is also fabricated in two parts to allow ready assembly and disassembly of the dispenser 40 if required.

The dispenser 40 can be mounted adjacent a pipe 54 used to transport flushing water into a toilet or urinal. Before the urinal or toilet is flushed, perhaps automatically by a timer, the pipe 54, inlet pipe 49 and water holding area 55 are all substantially empty of water. Accordingly, the piston 13 is in its lowest position, as depicted in Fig. 2.

On the occurrence of a flush, water travels rapidly through the pipe 54. A portion of the water is directed by the feed pipe 49 through the inlet 44 and into the water holding area 55 of the chamber 41. As the water level rises in the water holding area 55, the float 14 also begins to rise which in turn leads to a relative movement of the piston 13 upwardly in the dispenser 40. As the float 14 moves upwardly, air trapped in the dispenser 40 is able to exit the chamber 41 through orifice 56. When the water holding area 55 is full, the float 14 has risen to its maximum extent, as depicted in Fig. 3, at which time the central post 25 of the piston 13 extends into the reservoir 11 containing the cleaning fluid and the orifice 17 is sealed by the second sealing surface 24. As the flush nears completion, the rate of flow of water through the pipe 54 begins to fall and eventually stops. During this time, the flow of water out of the water holding area 55 through outlet 45 and drain pipe 51 is greater than that entering through inlet 44. The float 14, accordingly, begins to drop relative to the dispenser 40 and eventually leads to the second sealing surface 24 exiting the lower end of the orifice 17 so allowing the metered dose of trapped cleaning fluid to enter the remaining water in the water holding area 55 and then be subsequently discharged with this water at the end of the flush into the toilet or urinal. The float 14 at the end of the flush has then returned to its lower position as depicted in Fig. 2 ready for the cycle to repeat on the occurrence of the next flush. While the use of single dispensers is described above, it will be appreciated that a plurality of dispensers might be utilised, especially for urinals that might extend along a wall. If desired, rather than filling each individual reservoir 11 directly with cleaning fluid, it can be envisaged that a separate refillable storage reservoir that supplied cleaning fluid to each dispenser, such as through pipe 48, could be utilised if desired. This would have the advantage of minimising the time taken to refill the dispensers with cleaning fluid than would be the case if each individual dispenser had to be accessed and refilled. A third embodiment of the present invention is generally depicted as

60 in Figs. 4-6. Again, for this embodiment, like features have been numbered in accordance with the numbering utilised in respect of the first two embodiments of the invention.

In this embodiment, the flotation means comprises a spherical float 61 attached to two float arms 62 that are in turn mounted to a cam assembly 63 that can rotate about a pivot point 64. The position of the float 61 on the arms 62 can be changed to vary the swept value of the float during rise and fall of water in the cistern in which the dispenser is placed. The cam assembly 63 pivots between two legs 65 that extend downwardly from the lower end of collar 15. The cam assembly 63 can be mounted on two lugs extending respectively inwardly from the legs 65. The cam assembly 63 has two cams 66,67 that are located at pre-set angles radiating from the pivot point 64. Both cams 66,67 are partially split at their ends distal the pivot point 64 so forming two sets of fingers which are a slightly greater distance apart than the diameter of the complementary cam drive slots 68,69 on the piston 13.

In this embodiment, the piston 13 has its longitudinal movement within the dispenser 60 limited by the piston seats 71 that have a diameter greater than the orifice 17 in the base of the reservoir 11. The upper piston seat serves to limit the downward stroke of the piston 13 as it reaches the lip surrounding orifice 17. The seat also forms a seal to substantially prevent chemical from passing under pressure from the reservoir through to the cistern. The lower piston seat limits the upward movement of the piston when it comes into contact with the lower lip surrounding the orifice 17. The lower piston seat when sealing the orifice 17 also prevents any water from the cistern passing back under pressure to the reservoir 11 and any chemical from the reservoir 11 leaking past the cistern 13 and into the catchment area surrounded by collar 15.

In this embodiment, the piston has two regions where the piston is defined by a post 25 of smaller diameter than the portions of the piston each side of the post 25. This results in the piston having two fluid collection areas. As in other embodiments, the total volume of each fluid collection area can be adjusted by the use of C-clips that can be inserted around the posts 25 to lower the total volume of fluid collected by each collection area. Directly adjacent the lower piston seat 71, the piston diameter reduces away from the piston seat in area 72. The area 72 of piston 13 serves to direct fluid collected from reservoir 11 towards two or three inlet ports that are in fluid communication with a bore 73 (depicted in phantom in Fig. 4) that extends through the piston 13 to an outlet port 74.

While the piston 13 is depicted with a upper piston seat 71 that is flat, it can be readily envisaged that the upper surface of the seat 71 could be conical or otherwise extend upwardly to a sharp point. In such an embodiment, a bottle containing cleaning fluid that is sealed by an aluminium, plastic or other suitable frangible membrane could be engaged with the engagement ridge 75 such that the sharp point pierces the membrane. This results in the reservoir 11 being filled with a suitable cleaning fluid without the necessity for the person serving the dispenser to in any way come into contact with the cleaning fluid.

The dispenser 60 is designed for a dual flush type cistern, in which only half the of the water in the cistern leaves the cistern and passes through the toilet or urinal when only the half flush mode is activated.

Fig. 4 depicts the dispenser 60 in stand by mode with the float 61 at its highest level and the dispenser ready to dispense cleaning fluid on the occurrence of the next flush of the cistern in which the dispenser 60 is placed. While not depicted, it can be readily envisaged that the reservoir 11 is sealingly engaged with a bottle containing cleaning fluid. When the float 61 is at its highest level, the piston 13 is also at its highest point of travel relative to the dispenser 60, with the lower piston seat 71 in engagement with the underside of the lip surrounding the orifice 17. Both of the fluid collection areas formed by the smaller diameter posts 25 are fully immersed in the cleaning fluid filling the reservoir 11. At this time, the catchment area 76 within the area defined by collar 15 has also filled with water from the cistern through slots 29 and cam 66 is fully engaged with cam drive 68.

On activation of the cistern such that only half its contents are flushed through the toilet or urinal, the float 61 immediately begins to lower in response to the falling water level in the cistern. By virtue of the connection of the float arms 62 to the cam assembly 63, the piston 13 is also driven downwardly. As the piston 13 moves relatively downwardly, the water in the catchment 76 begins to drain through bore 73 of the piston 13. As the aperture of the outlet port 74 is less than that of the combined areas of the apertures of the inlet ports of the bore, a venturi effect is produced which leads to the liquid moving through the bore 73 to be ejected relatively quickly from the outlet port 74.

As is depicted in Fig. 6, once the water level in the cistern has lowered sufficiently, the first fluid collection means has moved through orifice 17 and dispensed a volume of cleaning fluid. The majority of the volume of this cleaning fluid runs down the piston 13 and is collected and fed through the inlet ports and into the water exiting the catchment 76 through the bore 73. If desired, the volume of the fluid collection means and that of the catchment 76 can be set to allow approximate control of the ratio of cleaning fluid to water as it is dispersed into the cistern. For example, in the depicted embodiment, the respective volumes are set to provide a water:cleaning fluid ratio of about 50:1.

The cleaning fluid and water exiting the port 74 is substantially ejected between the float arms 62 to prevent substantial build up on the float arms 62 or other parts of the dispenser 60.

At the end of the flush, the cistern begins to again fill with water. This results in the float 61 and in turn the piston 13 rising upwardly back to the position depicted in Fig. 4 ready for the cycle to be repeated.

If the full flush mode of the cistern is activated, all of the contents of the cistern are flushed through the toilet or urinal. In this case, the dispenser 60 operates as described above in relation to the half mode, except that as the water in the cistern continues to fall beyond the level depicted as 77, cam 67 engages cam drive 69 (see Fig. 6) so leading to the piston 13 falling further relative to the dispenser 60 until the second of the fluid collection means dispenses a second volume of cleaning fluid from the reservoir 11. By this arrangement, the dispenser 60 serves to provide two metered doses of cleaning fluid into the cistern if full flushing of the cistern is activated. The provision of the two fluid collection means on the piston 13 depicted in Figs. 4-6 can be readily envisaged as being present on the piston 13 used on the dispensers 10 and 40 described above. As the water level in the cistern begins to rise and the fluid collection areas move back through the orifice 17, they each transfer an equal volume of air to the reservoir 11 as the cleaning fluid is dispensed thereby maintaining equilibrium of pressure in the reservoir 11. This serves to seal the reservoir from the atmosphere and help prevent drying out of the cleaning fluid. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A device for dispensing a metered dose of a first fluid into a second fluid that has a surface that varies in height, the device including: a reservoir for the first fluid, the reservoir having an orifice disposed proximate a lower end thereof; a piston relatively movable through the orifice and having a first sealing surface, a second sealing surface, and a first fluid collection means separating the first and second sealing surfaces; and a flotation means that can move in concert with the varying height of the second fluid surface; the flotation means being adapted in use to move the piston between at least a first position, where the first sealing surface is sealing the orifice and the first fluid collection means is outside the reservoir, and a second position where the second sealing surface is sealing the orifice and the first fluid collection means can collect the first fluid from inside the reservoir, and then back to the first position to dispense the collected first fluid to outside of the reservoir.

2. The dispensing device of claim 1 wherein the flotation means includes an outwardly extending frusto-conical member having an upper and lower surface.

3. The dispensing device of claim 2 wherein the upper surface of the frusto-conical member is attached to the piston below and adjacent the second sealing surface such that its longitudinal axis is aligned with the longitudinal axis of the piston.

4. The dispensing device of claim 3 wherein a fluid catchment means is disposed on the upper surface of the frusto-conical member.

5. The dispensing device of claim 4 wherein the fluid catchment means is provided by a wall extending upwardly from the upper surface of the frusto- conical member.

6. The dispensing device of claim 5 wherein the upwardly extending wall is cylindrical and extends upwardly adjacent an outer edge of the upper surface so forming a catchment means provided by the upper surface of the frusto-conical member and the upwardly extending cylindrical wall.

7. The dispensing device of claims 5 or 6 wherein a fluid outlet means is formed in the wall above and adjacent its connection to the upper surface of the flotation means to allow the fluid to exit the fluid catchment means.

8. The dispensing device of claim 7 wherein the fluid outlet means is a discontinuous slot extending about some or all of the perimeter of the upstanding wall.

9. The dispensing device of claim 7 wherein the fluid outlet means is a number of orifices regularly spaced around the perimeter of the wall.

10. The dispensing device of any one of claims 6 to 9 wherein an outer surface of the wall comprising the fluid catchment means is adapted to move relatively within a surrounding collar having an inner surface shaped to match the shape of the outer surface of the upstanding wall on the flotation means.

11. The dispensing device of claim 10 wherein the collar comprises a downwardly extending extension of the reservoir.

12. The dispensing device of claims 10 or 11 wherein the collar has a fluid inlet means disposed to allow the second fluid to enter the collar and be caught by the fluid catchment means.

13. The dispensing device of claim 12 wherein the collar has a fluid outlet means disposed to allow fluid exiting the fluid outlet means of the upstanding wall to also exit through the collar when the piston is in the first position.

14. The dispensing device of claim 13 wherein both the fluid inlet means and fluid outlet means of the collar each comprise a discontinuous slot extending about some or all of the perimeter of the collar.

15. The dispensing device of any one of claims 10 to 14 wherein the lower edge of the collar has a plurality of downwardly extending fingers about its periphery to help disperse the fluid exiting the fluid outlet means of the collar.

16. The dispensing device of claim 15 wherein the fingers are equally spaced about the periphery.

17. The dispensing device of any one of the preceding claims wherein the first and second sealing surfaces are provided by respective cylindrical portions of the piston.

18. The dispensing device of claim 17 wherein the fluid collection means is provided by a central post of smaller diameter than the respective cylindrical portions and extending between them, with the smaller diameter of the central post defining the piston between the respective cylindrical portions and the distance between the cylindrical portions setting the volume of the first fluid collected by the first fluid collection means when the piston is in the second position.

19. The dispensing device of any one of the preceding claims wherein and end of the piston distal the flotation means has a boss that serves to limit the travel of the piston through the orifice in the lower end of the reservoir.

20. The dispensing device of any one of the preceding claims wherein the piston is comprised of two or more interconnectable parts to allow ready assembly or disassembly of the piston as required.

21. The dispensing device of claim 18 wherein the size of the collection means is adjustable by attaching one or more C-clips of differing dimensions around the central post so as to occupy a portion of the volume of the fluid collection means and so control the volume of first fluid collected and dispensed by the device.

22. The dispensing device of any one of the preceding claims wherein the reservoir includes a cylindrical chamber with its lower end comprising a substantially flat base.

23. The dispensing device of claim 22 wherein the orifice is formed at the centre of the base.

24. The dispensing device of claims 22 or 23 wherein the orifice has about its periphery a wall extending upwardly therefrom and having an inner surface adapted to seal with the first and second sealing surfaces of the piston as the piston moves relative thereto.

25. The dispensing device of claim 24 wherein the height of the wall about the orifice is greater than the length of the fluid collection means of the piston.

26. The dispensing device of any one of the preceding claims wherein the reservoir comprises a sealable chamber.

27. The dispensing device of any one of the preceding claims wherein the device is positioned within an outer chamber that engages the outer surface of the device and contains the second fluid.

28. The dispensing device of claim 27 wherein the outer chamber has an inlet disposed separate from a lower end thereof to allow the second fluid to enter the chamber, and an outlet positioned at its lowest end to allow the second fluid to exit the chamber.

29. The dispensing device of claim 28 wherein at least one orifice is provided in the chamber wall adjacent its upper end to allow air to escape the chamber on entry of the second fluid through its inlet.

30. The dispensing device of claim 1 wherein the flotation means comprises a float mounted on at least one float arm extending outwardly from a cam assembly, the assembly having at least one cam that can engage with a complementary cam drive on the piston, and wherein movement of the float in response to the varying height of the second fluid results in rotation of the cam assembly and so movement of the piston relative to the dispenser.

31. The dispensing device of claim 30 wherein the float is a sphere, a cylinder or an ellipsoid.

32. The dispensing device of claims 30 or 31 wherein the cam assembly is supported between two legs extending downwardly from the dispenser.

33. The dispensing device of any one of claims 30 to 32 wherein the piston has two fluid collection means.

34. The dispensing device of any one of claims 30 to 33 wherein the piston has a bore in fluid communication with plurality of inlet ports located proximate the fluid collection means and an outlet port located distal the fluid collection means, the bore being adapted to allow at least the first fluid to drain from the dispenser.

35. The dispensing device of any one of the preceding claims wherein the device is fabricated from a polymeric material such as polyfvinyl chloride) (PVC) or polymethylmethacrylate (PMMA).

36. The dispensing device of any one of the preceding claims wherein the first fluid is a cleaning and/or odour-neutralising fluid.

37. The dispensing device of any one of the preceding claims wherein the second fluid is water used to flush toilet bowls and urinals.

38. The dispensing device of any one of the preceding claims wherein the device is mountable in a cistern of a toilet and is adapted to only dispense the first fluid when the toilet is flushed.

39. The dispensing device of any one of claims 1-29 or 35-37 wherein the device is mountable on or in a pipe carrying flushing water to a toilet or urinal.