It is known to use venturi flow in movement of a second liquid such as shown in US 5,179, 969 for removal of free standing water from a roof. However, generally such systems use a solid heavy duty metal venturi system which is connected to a flexible light weight siphon system. In this way the siphon head can be placed at the position of the pool of water on the roof and connects back by an extended pipe to the flow centre having the venturi flow means mounted fixedly on the side wall of the building to enable a suction of the water from the roof into the recovery system.

In another US patent document 4, 332, 044 there is shown a means of emptying a water bed by use of a siphon pump attached directly to the mattress outlet and can be secured to an integrally formed storage chamber in the mattress whereby flow through the venturi pump forms a decrease in pressure to allow outlet of the water from the water bed through an outlet tube to a drain. Such apparatus is primarily fixed or able to be fixed to this particular connection.

Clearly from the above the particular venturi system needs to be specifically made and have specific connections for the particular application. Further they are generally formed from heavy duty metal and because of their specific requirements are expensive to make and difficult to move.

Also in US 5,695, 654, there is disclosed an apparatus and method for draining, cleaning and filling a fish aquarium. The venturi means has three connecting points with one connecting directly to a faucet and having an outlet feeding directly to the normal water

outlet of the faucet and an intermediate connection point for an extended hose extending from the position of the faucet to the aquarium. For the outlet material to be collected or discarded at a different point from the normal water faucet outlet, a further connection must be made to the outlet of the venturi means. This three connection venturi system, therefore, requires specific connections for the three mounts and requires specific hoses connecting the venturi meter to the aquarium. Clearly there are limits on its use and position of use.

It is an object of the invention, to provide a fluid flow pump that is particularly versatile in its use and particularly cost effective in its form of manufacture due to its construction In accordance with the invention there is provided a fluid flow pump having a pump body with an input enclosed channel leading to an output enclosed channel with an interruption between the input and output channels formed by an opening fluidly connected to the exterior surrounds ; the input channel having a constricting outlet at the interruption and able to feed fluid from the inlet channel to an opening of the outlet channel at the interruption: and a venturi-shaped formation made at least partially of a substantially non-erodin material and able to be connected at or near the output channel at the interruption wherein a venturi effect is formed at the interruption so that fluid flow from the inlet channel into the outlet channel draws fluid and any suspended particulate matter from outside the pump into the opening and into the outlet channel.

The fluid flow pump can have the venturi-shaped formation attached to the end of the outlet channel at the interruption, or the venturi-shaped formation could be an insert received within the end of the outlet channel at the interruption.

A fluid flow pump in accordance with the invention can have the venturi-shaped formation with an internal channel with a first frusto-conical restricting diameter portion and

a second fmsto-conical enlarging diameter portion so as to provide the venturi effect. It may further have an intermediary tubular constant diameter portion between the first and second portion. In one form the venturi-shaped formation is internally shaped to provide a venturi effect when the inlet channel and the outlet channel have the same cross-sectional flow area.

The relative lengths of the first. intermediary and second portions can be approximately in the ratio 2: I : 4 with the first portion having an angle of the frusto-conical shape of between 10° and 25° and preferably 18° and the second portion having an angle at the friisto-conical shape of between 2° and 8° and preferably 3°.

Preferably. the fluid flow pump of the invention has the external connection inlet and outlet at the beginning of the inlet channel and end of the outlet channel respectively are able to be connected to hoses for ready supply of fluid source and removal of the fluid combining the fluid source and fluid and material drawn into the fluid flow pump. The external connection inlet and outlet can be substantially adjacent with the inlet and outlet channels substantially forming a U-shape.

The fluid flow pump can be used with domestic mains pressure water supply and able to be readily connected and disconnected to domestic garden hoses such as by snaplocks for ready suction of domestic sumps such as swimming pools, garden or garage puddles etc.

In one form of the invention there is provided a moulded plastic body with an internal interrupted channel connected between respective external connection inlet and outlet, able to be formed into a single integral body. with the channel being interrupted by an opening fluidly connected to the exterior surrounds: and an insert formed at least partialiv of a harder material than the moulded plastic body and able to be received in the channel on the exit side of the opening to form a venturi effect structure at the opening wherein a constricting outlet at the interruption of the channel is able to feed fluid from the external connection inlet into

the opening and directly across to a relative enlarged inlet holding the insert and feeding to the continuation of the channel the insert being internally shaped such that flow along the interrupted channel and across the opening draws fluid and any suspended particulate matter from the exterior surrounds into the insert and to the external connection outlet of the channel. The moulded plastic body can be elongated and shaped and the channel constructed such that the external connection inlet and outlet are at or near a first end of the moulded plastics bodv and the opening forming the channel interruption is at or near the opposite end and wherein a substantial portion of the interrupted channel before and after the interruption of the channel are of similar dimensions and coextend substantially adjacent and formed integrally and wherein the insert is formed of metal.

The invention also provides a method of forming a fluid flow pump comprising the steps of : (a) forming a pump body with enclosed inlet and outlet channels with an interruption therebetween forming a fluid connection to the exterior surrounds ; (b) forming a venturi-shaped formation from a substantially non-eroding material : (c) connecting the venturi-shaped formation at or near the output channel at the interruption to form a venturi effect at the interruption so that fluid flow from the inlet channel into the outlet channel draws fluid and any suspended particulate material into the opening and into the outlet channel.

The method can have the step of forming inlet and outlet channels comprising moulding two parts each with one inlet groove and one outlet groove such that combining the two parts in respective alignment forms enclosed inlet and outlet channels. Also the method can have the step of connecting the venturi-shaped formation comprises forming location shapes in or adjacent the outlet grooves adjacent the interruption and locating the

venturi-shaped formation in one outlet by the location shapes prior to placing the other moulded part having the other outlet groove in relative position to form the enclosed outlet channel and at least substantially encapsulate the venturi-shaped formation. The body with the inlet and outlet channels can be moulded from plastic and the venturi-shaped formation is made from metal able to withstand corrosive or eroding effects of fluid and material being drawn into the outlet channel.

It can be seen that the construction of the invention provides a substantial advantage in its manufacture. Instead of being a large fixed bulkv construction or made from copper or brass as other venturi type pumps this can be easily constructed substantially from plastics.

I'recisely shaped flow structures to provide a venturi constricting opening are extremely difficult and costly to make from plastics. As normal plastic will generally be eroded over a short time by contact with particulate matter such as sand. it is generally not feasible to make such an item from plastic. However, the apparatus of the invention is able to use harder plastics onlv for the insert which are able to withstand sand erosion and therefore be useable in more circumstances. The apparatus of the invention is also able to make use of metal characteristics and strength and shaping flexibility in combination with the benefits of plastics. The particular structure of the invention including the insert construction allows these avantages to be used which have not previouslv been able to be effectively used.

The invention in one particularly advantageous form provides a fluid flow pump further having the moulded plastic body being elongated and shaped and the channel constructed such that the external connection inlet and outlet are at or near a first end of the moulded plastics body and the opening forming the channel interruption is at or near the opposite end and wherein a substantial portion of the interrupted channel before and after the interruption of the channel coextend substantially adjacently.

This particular structure provides the dual benefit of allowing minimal plastic use in the moulding process and a stronger structure while providing a useful structure that can have its external connections at one end connected to required hoses and allow the other end to be inserted into the pool of liquid to be transported away.

In order that the invention is more readily understood, a particular embodiment thereof will be described by way of illustrations with reference to the drawings wherein: Figure 1 is a front view of a fluid flow pump in accordance with a first embodiment of the invention.

Figure 2 is a side view of the fluid flow pump of Figure I.

Figure 3 is a vertical cross sectional view of preferred insert able to be used in the fluid flow pump of Figure 1.

Figure 4 is a front view of a fluid flow pump in accordance with a second embodiment of the invention.

Figure 5 is a side view of the fluid flow pump of Figure 4.

Referring to the drawings there is shown a fluid flow pump 10 having a substantially U shaped interrupted channel comprising inlet channel 17 and outlet channel 18. The fluid flow pump 10 uses the venturi effect to draw external liquid into the outlet channel 8 at an opening 35 forming an interruption in the channels 17 18 between an external connection inlet 31 and an external connection outlet 33.

The fluid flow pump comprises a moulded plastic body 10 being substantially planar and elongated with the integral internal interrupted U-shaped channel 17, 18 connected between an external connection inlet 31 and outlet 32 at or near one end of the body 15.

The inlet 31 and outlet 32 both have a snap-on structure for ready connection to snap-on

structures used with domestic garden hoses or the like. The channel 17, 18 is interrupted by the opening 35 near the distal end. This allows the channel 17, 18 to be fluidly connected to the exterior surrounds. A substantial portion of the inlet channel 17 and outlet channel 18 before and after the interruption of the channel coextend substantially adjacently.

The moulded body 10 is formed by two mirror body parts 11, 12 which each have corresponding grooves such that joining the two parts in alignment the grooves form enclosed tubular channels 17, 18.

A venturi shaped formation, in the form of an insert 41 and made preferably of brass, is received in the channel 17. 18 during manufacture and form a venturi effect structure at the opening 35. The insert 41 has an internal shape of opposing frusto conical shapes and feeding to and expanding to the internal dimensions of the outlet channel 18.

The interruption of the channel 17, 18 begins at the end of the first continuous channel part 17 shortly after negotiating the [J-shape end bend with a frusto conical shaped constricting outlet 45. The outlet 45 is able to feed liquid into the opening 35 and directly across an inlet 47 of the insert 41 at the beginning of the linear extending outlet channel 18.

In this way flow of a liquid along the inlet channel 17 and across the opening 35 to the venturi shaped formation insert draws liquid and any suspended particulate matter from the exterior surrounds around the opening 35 into the enlarging inlet 47 and to the external connection outlet 33 of the channel.

Referring to Figure 3, there is shown a particularly preferred metal insert 41 having a constant outside circular dimension except for an enlarged placement ring 51 near one end of the metal insert 41. This placement ring 51 is sized to fit within a metal insert locating groove 44 comprising an enlargement of the outlet channel 18 and a subsequent enlargement of the external moulded structure. The metal insert 41 has a continuous internal channel

comprising three portions being a first opening portion 53 which is frusto conical in shape and has its largest opening leading from its inlet 47 leading from the opening 35 between the two parts of the channel 17, 18. The first opening portion 53 feeds into a middle portion 54 having parallel tubular sides with the same dimension as the smallest dimension of the opening portion 53 to allow smooth flow and leading to the third part being an exit portion 55 also being frusto conical extending from the smallest dimension equal to the dimension of the middle portion 54 to a larger dimension just smaller than the internal dimension of the second channel part 18. T he relative lengths of each portion are approximatelv in ratio of 2: 1 : 4 from the opening portion 53 to the middle portion 54 to the exit portion 55.

In operation the external connection inlet 31 will be connected to a main water pressure hose connection feeding water down the first channel part 17 having an outer circumference of about 18 mm and inner circumference of about 14 mm and extending around the U-bend to a constricting outlet 43. The outlet 43 size is about 3 mm feeding water directly across the opening 35 of about 4 mm to the opening portion 53 of the insert 41 with an opening of just less than 13 mm circumference leading to the middle portion having an internal circumference of about 10 mm which feeds to the exit portion having an outlet size of about 15 mm and feeding back into the second channel part 18 having an internal circumference of about 14 mm and external dimensions of about 18 mm. The opening portion 53 has an angle of the frusto conical shape of about 18° while the exit portion 55 has an angle of about 3°.

The shaping around the external part of the constricting outlet 43 is also substantially frusto conical allowing ready access of the external liquid adjacent to the 3 mm outlet and in the opening 35 to the opening portion 53 of the metal insert 41.

By means of the increase of speed of the flow due to the constricting outlet 43 and the enlarging diameter of the exit portion 55 of the metal insert 41 to allow a lower pressure relative to the fluid around the opening 35, the fluid and any particulate matter around the opening 35 is drawn into the metal insert 41 and into the second channel part 18 to exit the external connection outlet 33.

Referring to Figures 4 and 5 there is shown a fluid flow pump 60 substantially the same as the fluid flow pump at Figures 1 to 3 but with an add-on attachable venturi-shaped formation 71 rather than an insert 41. This venturi-shaped formation 71 is able to be connected to the shortened outlet channel 18 bv internal or external screw thread or clip means or the like. Thereby the liquid is directed into the venturi-shaped formation from the inlet channel 17 so as to have the venturi-shaped formation in linear alignment with an outlet 43 of the inlet channel 17 and an inlet 77 of the outlet channel 18.

It should be noted that the above description of the embodiments are illustrative and not restrictive of the scope of the invention which is defined by the foilowing claims.