However, the invention is not restricted in its application to domestic cleaning. Moreover, the invention may be used with other liquids and/or gases for commercial or industrial purposes.

Background to the Invention It is known to provide detergents or similar concentrates in containers incorporating mixing attachments designed to mix the contents of the container with water supplied to the attachment through a conventional garden hose fitting. Such arrangements are ideal for washing the external walls of houses or garden paths or other exterior surfaces. These attachments generally operate by utilising the venturi effect whereby the diluent, that is the water, passes over the top of the supply tube of the concentrate ie the detergent, such that the water creates a suction at the supply tube to draw the detergent into the flow of water and thereby mix the detergent with the water. Such attachments have a number of disadvantages. Firstly while they operate effectively with the faucet fully open, they are less effective at a lower flow rate. Therefore, such arrangements might not be appropriate for domestic cleaning operations requiring a more controlled delivery of detergent and diluent. Compare a house washing operating with cleaning a car. In the house washing operation it might be appropriate to have the water pressure at full strength to assist with the removal of debris from the side of the house especially since most parts will be out of reach of the user. On the other hand, consider a car washing operation in which it is desirable that the detergent and diluent be delivered at a low or medium flow to enable thorough washing of the car without wastage of detergent and/or water. Known arrangements will not function properly at certain reduced delivery rates.

Known arrangements as described above also suffer from the disadvantage that the detergent might not get well mixed with the diluent. A further shortcoming of known arrangements is that if they are to be used with further attachments downstream then a one way valve is a requirement to prevent backflow and contamination of the water supply.

It will be understood that with known arrangements, the venturi effect operates just as well under backflow conditions as it does under normal conditions to draw detergent from the

supply. The addition of a one way valve will lead to increased complexity and cost of such mixing arrangements.

Other known arrangements generally used for commercial purposes include an electric pump for one or both of the liquids to be mixed. It will also be understood that the use of a pump increases the complexity of such arrangements.

It is therefore an object of the present invention to provide a venturi feed device which overcomes or ameliorates at least one of the above mentioned disadvantages or at least provides the public with a useful choice.

Summary of the Invention In accordance with a first aspect of the present invention there is provided a venturi feed device including a bore for flow of a first liquid, the bore including a constricted region followed by a divergent region defined by one or more progressively diverging flow surfaces downstream of the constricted region, there being one or more openings provided in the diverging flow surface (s), the or each opening being connectable to a source of a second fluid.

Preferably the constricted region is defined by a necked or waisted region of the bore.

This may be created by a convergent region followed by the divergent region immediately downstream of the convergent region. The divergent region means a progressive widening of the diverging flow surface (s) or in other words a progressive increase in the cross-sectional dimension of the diverging flow surface (s). Preferably the diverging flow surface (s) extends at an angle of approximately 45 ° to the longitudinal axis of the bore.

It is contemplated that the diverging flow surface may be a single surface eg an internal frusto-conical surface. As an alternative the internal surface of the divergent region may be paraboloidal or concave. On the other hand the divergent region may be defined by multiple diverging flow surfaces. For example, consider the case where the side walls of the bore define a truncated pyramid.

Suitably, the venturi feed device includes means to induce flow of liquid along the diverging flow surface (s). However this is not essential because if the feed device is embodied in a spray nozzle which exits only a short distance downstream of the divergent region then priming to induce the flow of liquid along the diverging flow surface (s) can be achieved with the user's finger placed over the exit for a few seconds. However in

many applications it will be desirable to have a self priming means. This may be in the form of a flow separator. In a preferred form of the invention a projection is provided at least partially in the divergent region with a closed end facing the divergent region. Preferably the projection is centrally located with respect to the divergent region so that the flow of the first liquid after passing through the constricted region is forced to flow around the projection and along the diverging flow surface (s) due to the obstruction provided by the projection. The projection may be a solid projection. In a most preferred form of the invention the projection has an end facing the diverging flow surface (s), the end having one or more inclined face (s) corresponding to the angle of the diverging flow surface (s).

The venturi feed device may be embodied in a fluid mixing device which has a first connection for connection of the device to a supply of the first fluid eg garden hose and a second connection for connection to a source of a second fluid eg a concentrated substance such as detergent to be diluted by the first fluid. The first and second fluids may be liquid or gas. Preferably the second connection is a threaded connection or a snap- fit connection to connect the fluid mixing device to a bottle of detergent. As mentioned above the or each of the openings in the diverging flow surface (s) are connectable to a source of the second fluid. Accordingly, a flow passage may be provided along which the second fluid can flow through to the or each opening. Additionally a pre-chamber may be provided in communication with the or each opening. This embodiment is particularly preferred where there are a number of openings to enable the second fluid to be evenly distributed through each of the openings. Preferably the fluid mixing device includes an aeration means to introduce air into either or both of the first and second fluids so that where the second fluid is a detergent the air will provide an appropriate foaming action.

The aeration means is preferably in the form of an air inlet provided into the supply of the second fluid. In a most preferred form of the invention this is achieved by having a stem which feeds detergent from a supply container into the pre-chamber connected to the or each opening. The stem has an aperture which draws in air as the second fluid is drawn by suction through the or each opening.

It will be understand that the downstream end of the constricted region will define an outlet from which the first fluid then passes into the divergent region. The or each opening may be arranged to surround the outlet of the constricted region. More particularly, the or each opening may be arranged equidistant from the outlet of the constricted region. The or each opening may be disposed intermediate the distance along the diverging flow surface (s). Preferably the or each opening is disposed towards the

constricted region along the diverging flow surface (s). The preferred distance is 1/4 to 2/5 along the length of the diverging flow surface (s).

In a most preferred form of the invention there are a plurality of openings provided in the diverging flow surface (s). These may be in the form of slots. However in a most preferred form of the invention the openings comprise a series of spaced circular apertures arranged in an annulus around the outlet of the constricted region. They may be closely spaced and a preferred number of apertures is 16. In a preferred form of the invention the area of the openings exceeds the area of the outlet of the constricted region.

In accordance with a second aspect of the present invention there is provided a venturi feed device including a bore for flow of a first fluid, the bore including a constricted region followed by a divergent region downstream of the constricted region, there being a plurality of openings provided in the divergent region, the openings being connectable to a source of a second fluid.

The openings may include any of the features described above in accordance with the first aspect of the invention. Other features of the venturi feed device may also accord with those features described in accordance with the first aspect.

In accordance with a third aspect of the present invention there is provided a venturi feed device including: a bore for flow of a first fluid, the bore including a constricted region followed by a divergent region defined by one or more diverging flow surfaces downstream of the constricted region; a flow separator to induce flow of the first liquid along the or each divergent flow surface, there being one or more openings provided in the divergent region, the or each opening being connectable to a source of a second fluid.

The flow separator may take the form of a projection as described in connection with the first aspect of the invention.

In accordance with a fourth aspect of the present invention there is provided a fluid mixing device including a body having a primary bore, a venturi feed device removably inserted into the primary bore including a secondary bore for flow of a first fluid, the bore including a constricted region and a divergent region downstream of the constricted region with one or more openings provided in the divergent region, the or each opening being connectable to a source of a second fluid.

Preferably the venturi feed device is moveable within the primary bore. The venturi feed device may be moveable by way of a sliding fit. In a preferred form of the invention the venturi feed device may include one or more flanges at the upstream opening of the secondary bore. If the primary bore is of cylindrical configuration then the flange will suitably be annular in shape.

The divergent region may be defined by one or more diverging walls. For example, the divergent region may be defined by a frusto-conical wall. The constricted region may be in the form of a convergent region. Alternatively the convergent region may be defined by a necked or waisted region. A tubular portion may include the convergent region in which case the tubular portion will extend between the flange (s) and the diverging wall (s) of the divergent region. In this construction the flange (s) abut the inner wall of the primary bore as do the diverging wall (s). With this configuration it will be appreciated that the flange (s), diverging wall (s) and tubular portion define an annular chamber surrounding the tubular portion. Preferably the annular chamber is in communication with the one or more openings and the annular chamber is also in communication with a supply of the second fluid.

The fluid mixing device may also include a flow separator to induce flow of the first fluid along the diverging wall (s). The flow separator may be embodied in a removable insert provided in the primary bore. Preferably, the removable insert is fitted onto the front of the body.

In accordance with a fifth aspect of the invention, there is provided a washing assembly including a portable fluid mixing device for mixing a first fluid with a second fluid, the mixing device being connectable to a source of the first fluid and connectable to a source of the second fluid, the mixing device further including a venturi feed means for feeding the second fluid into the flow of the first fluid wherein the assembly further includes a washing pad or mitt through which the mixed first and second fluids is dispersed, the pad or mitt being connected to the fluid mixing device by a length of conduit sufficient to enable a user to hold the portable mixing device in one hand and the washing pad or mitt in the other.

Preferably the conduit extends into the pad so that the outlet of the conduit distributes the mixed fluids somewhat evenly across the pad. The pad may be in the form of an enclosed mitt to receive the users hand. Alternatively, the pad may simply include a finger hold or finger grips for user manipulation of the pad over the surface to be cleaned.

The fluid mixing device may include a connection suitable for attachment to a conventional garden hose. The connection may be a threaded connection or alternatively a snap connection may be provided. Suitably the connection to the source of the second fluid is by way of a threaded connection between the fluid mixing device and the top of a container of the second fluid.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

Brief Summary of the Drawings In order that the invention may be more fully understood, some embodiments will now be described by way of example with reference to the drawings in which: Figure 1 is a side partially sectional view of a first preferred embodiment of a fluid mixing device in accordance with the present invention; Figure 2 is an end and part sectional view of a component forming part of the fluid mixing device shown in Figure 1; Figure 3 is an end and sectional view of a venturi feed device forming part of the fluid mixing device shown in Figure 1; Figure 4 is a sectional view of a second preferred embodiment of a fluid mixing device according to the present invention; Figure 5 is a top view of a washing pad adapted for use with the fluid mixing device shown in Figures 1 and 4; Figure 6 is a side view of the washing pad shown in Figure 5; Figure 7 is a sectional view through the washing pad shown in Figure 5; Figure 8 is an underside view of the washing pad shown in Figure 5; Figure 9 is a perspective view of a foam portion of a washing pad according to a second preferred embodiment; Figure 10 is a plan view of the foam portion of Figure 9; Figure 11 is an exploded elevation illustrating the portions of the washing pad

according to a second preferred embodiment; and Figure 12 illustrates a third preferred embodiment of the mixing device.

Preferred Embodiments of the Present Invention Figure 1 illustrates a first preferred form of a fluid mixing device 10. The fluid mixing device 10 includes a body 12 which is substantially T-shaped in side view as illustrated including a top elongate portion 16 and an intermediate portion 18. The top portion 16 has a primary central bore 14 extending therethrough from an inlet opening 20 to an outlet opening 22. The body 12 also provides a connection to a supply of a first fluid ie water by means of an external thread 28 provided on the external periphery of the top portion 16 of the body 12 adjacent the inlet opening 20. The external thread 28 is shaped for engagement with an internal thread provided on a conventional garden hose coupling.

Inserted in the other end of the elongate portion 16 is a venturi feed device 30. Figure 3 illustrates a slightly modified portion of the parts of the venturi feed device 30. The venturi feed device 30 has a first tubular portion 32 and a second frusto-conical portion 34 terminating in an annular flange 36. The tubular portion 32 has a secondary bore 38 extending therethrough. The second bore 38 includes a constricted region 40. The constricted region 40 includes an outlet 42 opening into a divergent region 46 defined by the internal surface of the frusto-conical portion 34. The frusto-conical portion 34 is comprised of a thin frusto-conical wall of uniform thickness. It can be seen from Figure 3 that the frusto-conical portion includes a series of small closely spaced apertures 50 in a circular array equidistant about the opening 42 of the constricted region 40. The combined area of the openings 50 is larger than the opening of the outlet 42 of the constricted region 40.

Reverting to Figure 1, the venturi feed device 30 can be viewed in its operative position at the downstream end of the top portion 16 of the body 12. The tubular portion 32 is inserted so that is outer wall is in close contact with the internal periphery of the central primary bore 14. This ensures that water entering the primary bore 14 through inlet opening 20 is forced through the tubular portion 38 and constricted region 40 of the venturi feed device 30.

Downstream of the venturi feed device 30 is a flow separator 60 more clearly illustrated in Figure 2. The flow separator 60 includes a central projection 62 having an end facing the outlet 42 of the constricted region with a conical end surface at an angle corresponding

to the angle of the frusto-conical portion 34. The projection 62 induces the flow to separate in the region of the projection and travel along the internal wall of the frusto- conical portion 34. Four slots 64 extend in a circular manner about the projection 62 to enable water to pass through the flow separator 60 and out through a nozzle portion 66.

The flow separator 60 shown in Figures 1 and 2 are not identical. The flow separator 60 shown in Figure 1 has an internal thread co-operable with an external thread provided on the top portion 16 adjacent the outlet opening 22 thereof. The flow separator shown in Figure 2 is externally threaded for cooperation with an internally threaded end of the top portion 16.

The intermediate portion 18 contains a third internally threaded bore 70 for screw connection to a complementary externally threaded top of a container containing a second fluid such as a detergent. A stem 70 extends into the container 71 towards its bottom end.

The stem 70 includes an aperture 72 for reasons which will be explained. The stem 70 extends up to a conduit and pre-chamber 75 which is in communication with the openings 50 in the frusto-conical portion of the venturi feed device 30.

The operation of the fluid mixing device will now be explained. With the garden hose (not shown) connected onto external thread 28 and the water turned on, the water is caused to flow through the primary bore 14 in the direction from the inlet opening 20 towards the outlet opening 22. When the water reaches the venturi feed device 30, the constricted region 40 in the venturi feed device creates a very high speed, high pressure, low volume water flow through the constricted region 40. A preferred diameter for the constricted region 40 is 0.050 inches (approximately 1.27 mm). On passing out through the outlet 42 of the constricted region 40, the flow of water is separated by flow separator 60 to pass around the projection 62. The water then passes along the internal surface of the frusto-conical portion 34 and out through the outlet opening 22, the slots 64 and the nozzle 66. As the water passes over the circular array of apertures 50 a suction is created in conduit and pre-chamber 75 which draws the detergent up the stem 70. The stem 70 may include a reducing portion 73 of approximately. 020 inches (approximately 0.508 mm) to limit the amount of detergent drawn therethrough.

Above the reducing portion 73 is an aperture 72 of approximately 0.020 inches (0.508 mm). This aperture enables air to be drawn into the system and mixed with the detergent to create a high level of sudsing. The mixture of detergent and air is then drawn into conduit and pre-chamber 75 and subsequently out through the series of openings 50 to mix with the water. Water and foamed detergent thus leave through the outlet of nozzle

66. This nozzle is preferably of approximately 8 mm. The fluid mixing device may be used to spray water onto any surface to be cleaned. Alternatively further attachments may be connected to the nozzle of the flow separator 60, see for example the conduit and pad shown in Figures 5 to 8.

Figure 4 illustrates a second embodiment of the fluid mixing device. Many of the parts are similar to the fluid mixing device showing in Figure 1 and like numerals represent like parts.

The main differences in the fluid mixing device 80 illustrated in Figure 4 compared to the device 10 of Figure 1, are for reasons of ease of manufacture. The primary bore 14 is of substantially uniform cross-section throughout apart from a slightly narrower region 82 adjacent the outlet end defining a shoulder 84.

The venturi feed device 32A includes tubular portion 32 and frusto-conical portion 34 as before but additionally includes an annular flange 86 at the upstream end of the venturi feed device 32A. The venturi feed device 32A is inserted into the primary bore 14 from the inlet end thereof and the annular flange 36 abuts against the shoulder 84. Preferably the venturi feed device 32A is a sliding fit within the primary bore 14. Since the venturi device 32A is removable, this facilitates the insertion of different venturi feed devices to suit the water pressure. The size of the constricted region 40 may be varied with different venturi feed devices according to the water pressure. For example, with lower pressure, the size of the constricted region would be reduced whereas for higher pressure the size of the constricted region would be enlarged.

The arrangement illustrated protects against reverse flow problems. As explained earlier in the specification, with conventional venturi devices backflow across the detergent supply continues to draw detergent out of the detergent supply with the potential for a high degree of contamination to the water supply. In the present invention if a backflow condition exists it will be appreciated that water is more likely to enter the series of apertures 50 rather than flow back through the very small outlet 42 of the constricted region 40. The small risk of contamination from diluted detergent flowing back through the constricted region 40 will result in minimal likelihood of contamination. In any case, with the greater likelihood of diluted detergent flowing back through apertures 50, a venturi effect will not be created to draw further neat detergent from the supply back into the water supply.

Figures 5 to 8 illustrate a wash pad for use in combination with the fluid mixing device 10 shown in Figure 1 or the fluid mixing device 80 shown in Figure 4. The wash pad 100 is comprised of a top nylon layer 102 secured by stitching to an intermediate foam layer 104 with a flock layer 106 provided on the downward side thereof. A conduit 108 extends from the pad 100 to the nozzle 66 of the fluid mixing device 10,80. The conduit 108 is of sufficient length to enable a user to hold the container 71 in one hand while utilising the wash pad 100 in the other hand.

Figure 7 illustrates the internal construction of the foam layer 104. In the illustrated embodiment the foam layer 104 has a central channel and four branches burned into the foam. The central channel receives the conduit 108. The conduit 108 has outlet apertures formed therein in alignment with the branches 110. Holes 112 are punched through the foam layer 104 and the flock layer 106 to enable water/detergent mix flowing through the conduit to pass out through the flock layer 106 providing sudsy water to enable washing of a car or other exterior surface to be cleaned. In an alternative embodiment the branches 110 are not provided and simply six holes are provided in the conduit 108 within the region of the pad aligning with six holes provided through the foam and flock layers 104, 106 of the pad. To construct the pad, the foam and flock layers 104,106 are adhered together. These layers may be adhered prior to cutting to shape. The foam layer 104 is then burnt out in the appropriate region to receive the conduit and/or form the branches and the holes 112 are cut through both layers 104,106. The conduit 108 is then placed in position. Appropriate adhesive may be required to secure the conduit 108 into position.

The right side of the upper nylon layer 102 is then applied to the flock layer 106 and the assembly is sewn around the boundary of the two apart from the edge where the conduit 108 enters the pad. The assembly is then turned inside out with stitching provided along the entire peripheral boundary. The conduit 108 may in fact exit the pad through the upper layer 102 to enable the pad to be fully sewn along that edge as well as locating the conduit away from the flock surface so as not to interfere with the surface being cleaned.

It can be seen in Figure 5 that the outer surface of the nylon layer includes a finger hold for insertion of the user's fingers to aid gripping the pad.

Figure 9 illustrates a foam portion 120 for a washing mitt according to a second preferred embodiment. The foam portion has flock fabric 122 adhered thereto. In plan, the foam portion 120 is curved at one end and square at the other end. The square end is cut so as to taper in thickness so that at that end there is basically only the thickness of the flock fabric 122. The foam portion 120 also has a central cut-out 124 extending from the tapered

part towards the curved end, substantially the length of the foam portion 120. The depth of the cut-out 124 is substantially to the flock fabric 122.

Down each side of the cut-out 124 is a line of holes 126. These holes which are aligned with the edge of the cut-out are formed by punching through the remaining foam and the flock fabric 122.

Figure 11 illustrates the arrangement of the portions making up the mitt according to the second embodiment. These portions include the foam portion 120, a cover portion 130 and a conduit portion 132. In the assembled mitt, the conduit portion 132 is inserted in the central cut-out of the foam portion 120. The conduit portion has holes 134 provided therein which align with the holes 126 punched through the foam portion 120. A connector 135 includes an integrally moulded extension piece 136.

In order to construct the mitt, the cover portion 130 is sewn (right sides together) to the foam portion along the external periphery apart from the square end. The assembly is then turned right side out and the conduit portion 132 and connector 135 are positioned within the cut-out with the end of the connector 135 extending out an aperture 137 in the cover portion 130. The tapered edge of the foam portion enables the raw edges to be turned inside and lie neatly against the foam portion. The edge is then sewn closed, overstitching the integrally moulded extension piece 136. This overstitching holds the extension piece and attached conduit portion 132 in position within the assembled mitt. It can be seen that the upper surface of the cover portion 130 includes a finger hold 138.

Figure 12 illustrate a third preferred embodiment of the mixing device. The mixing device 140 operates on the same principles as the first and second embodiments 10,80. The main difference is the incorporation of a selector valve which enables the user the select between three different operational modes of the mixing device 140. The selector knobs 142 enables the user to select the position of the selector valve. There are two knobs 142 so that the user can operate either one depending on whether the user is left or right handed. Referring to the knob shown in Figure 12, the selector knob 142 is movable between 3 different positions. At a first"up"position at which the knob 142 is disposed at about 2 o'clock, the valve allows water to flow in through the device and straight out through the rinse nozzle 144. At the 3 o'clock position of the knob, the valve is positioned at the off position to cease water flow through the device. At the"down"position at approximately 4 o'clock, the valve is positioned to allow for water flow through the device in a manner which provides for mixing with the detergent in the container 71 as

described in connection with previous embodiments. Reference is made to US 4696593 which describes a possible internal configuration of a selector valves for the present invention.

The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.