AU773819B2

AU773819B2 - A venturi

Info

Publication number: AU773819B2
Application number: AU37084/01A
Authority: AU
Inventors: Desmond John Berry; Robert Kenneth Mcnab
Original assignee: EDGETEC SYSTEMS Pty Ltd
Current assignee: EDGETEC SYSTEMS Pty Ltd
Priority date: 2000-04-17
Filing date: 2001-04-17
Publication date: 2004-06-10
Anticipated expiration: 2021-04-17
Also published as: AU3708401A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): EDGETEC SYSTEMS PTY LTD Invention Title: A VENTURI The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 A VENTURI This invention relates to a venturi especially for use in mixing jet assemblies for spa baths and pools.

It is however understood that the venturi could be used in other environment such as jet pumps.

Mixing jet assemblies for spa baths and pools conventionally use a venturi that accelerates the water to draw in air to mix air with water to provide the effect of a bubbling delivery. Users of such equipment require aerated water that has a comfortable feel. This means there has to be a high proportion of air within the water but the pressure must not be too extreme nor the mixture too turbulent. There is also a constraint on the amount of power available to mix the water with air to provide the desired effect. The venturi is an important component of such equipment and this invention relates to an improvement in venturis especially for equipment of this kind.

According to the present invention there is provided a venturi adapted to mix fluids comprising a converging nozzle having a mouth joined to a throat via a mixing chamber, the converging nozzle being arranged to be 25 coupled to a first fluid to in use accelerate said fluid :through the nozzle to exit the mouth as a jet stream, the mixing chamber being adapted to be coupled to a source of second fluid which mixes with the jet stream in the mixing S: chamber to leave the throat as a mixture of fluids characterised in that means is provided upstream of the mixing chamber to additionally introduce the second fluid within the jet stream of the first fluid.

Preferably the first fluid is water and the second fluid is air.

In a preferred embodiment, a plenum chamber \\melb_files\home$\MCooper\Keep\Speci\PQ6951 BERRY MCNAB-CAP.doc 6/04/04 3 having a mouth and a closed end, the chamber being supported centrally of the nozzle with the closed end upstream of the flow, radial passageways extending from the plenum chamber to the exterior of the nozzle to provide communication with the second fluid. Preferably, the exterior of the plenum chamber is tapered to diverge outwardly downstream of the nozzle. In a preferred embodiment, the plenum chamber is supported by three radially extending vanes, each vane being hollow to act as a fluid passageway. The vanes preferably act as means to straighten out rotational forces that the fluid may possess as it flows through the nozzle.

In a preferred embodiment, the venturi is 15 incorporated in a mixing jet assembly for spa baths and pools.

An embodiment of the present invention will now be described by way of example only with reference to the eeeee* 20 accompanying drawings in which: Figure 1 is a cross-sectional view of a mixing Jet assembly for use in a spa bath or pool incorporating an *improved venturi, Figure 2 is a perspective side view of part of the mixing jet assembly, Figure 3 is a perspective view of the front of the assembly illustrating the front of the invention, Figure 4 is a perspective sectional view of the assembly, and Figure 5 is a perspective sectional view of the assembly when coupled to ancillary pipework.

The mixing jet assembly 10 illustrated in the accompanying drawings is essentially composed of four components that are injection moulded in plastics. The four components comprise a receptor-retaining nut 20, a jet \\melbfiles\homeS\MCooper\Keep\Specii\PQ6951 BERRY MCNAB-CAP.doc 17/04/01 4 tube and receptor 30, a decorative face plate 60 and an eyeball 50. The components are designed so that they can be readily assembled to provide the characteristics required by a mixing jet assembly whilst at the same time facilitate attachment of the assembly to the wall of a spa bath or pool. The assembly is also designed to provide an appropriate degree of disassembly without the need for complicated tools.

As shown in Figure 1, the assembly 10 is arranged to be screwed into an internally threaded bore 4 of a housing 7. The housing 7 shown in Figure 5 forms part of an array of pipes that provide water and air to the assembly. The housing 7 terminates in an annular outer 15 flange 6 which is adapted to abut the exterior surface (not shown) of the wall of the spa or pool, and the assembly is clamped to the wall through abutment of an annular flange 21 that is provided on the radial extremity of the receptor-retaining nut 20. Thus, the receptor-retaining 20 nut 20 is externally threaded at one end 22 so that it can be screwed into the threaded bore 4 of the housing 7 to clamp the wall of the spa or pool between the flanges 6 and 21.

o The receptor-retaining nut 20 has a substantially cylindrical internal bore 24 that terminates at the inner end in an annular rib As shown in Figures 2 and 3 the jet receptor is moulded to be integrally formed with a jet tube 31. The jet tube 31 is positioned centrally of the receptor 30 by four webs 12, 13, 14 and 15 and is of substantially cylindrical configuration with an arcuate semi-cylindrical cut-out 32 at one end. The jet tube 31 is supported centrally of a cylindrical receptor member 34 that is a sliding fit within the bore 24 of the retaining nut The receptor member 34 terminates in an annular flange \\melbfiles\home$\MCooper\Keep\speci\PQ6951 BERRY MCNAB-CAP.doc 17/04/01 5 at the front of the receptor. The external profile of the jet receptor 30 is stepped from the annular flange 35 down to a cylindrical portion 36 to an end portion 39. As shown in Figures 1 and 2 the inner end portion 39 has four axially extending cut-outs 41 that define a pair of diametrically opposed locking tongues 42, 43. Each tongue ends in an upstanding arcuate rib 44 as shown in Figures 2 and 3. The diameter of the arcuate ribs 44 is slightly greater than the inner diameter of the end face 25 of the retaining nut 20 and thus the jet receptor 30 is arranged to be a snap fit within the bore of the retaining nut by pushing the receptor 30 into the retaining nut 20 and causing the ribs 44 on the two tongues 42, 43 to deflect radially inwardly to snap into engagement behind the surface 25 as shown in Figure 1. Thus, the jet receptor can be snap-fitted into engagement with the retaining nut :I 20 thus preventing axial displacement of the receptor S: relative to the nut with the receptor free to axially rotate relative to the nut As shown in Figure 1 the receptor 30 has an internal bore 49 that supports the jet tube 31. The bore also terminates in a part spherical recess 45 which is profiled to accommodate a similarly spherically curved surface 51 of the eyeball 50. The spherically curved outer surface 51 of the eyeball reduces in diameter to terminate in a cylindrical forward portion 52. The eyeball 50 has an internal bore 53 that tapers inwardly from the front to the rear to join an enlarged end bore 54 that fits closely with the extremities of the internal bore of the receptor The eyeball 50 is held in position within the receptor bore by means of the decorative face ring 60 that has an inner portion 61 that is adapted to be a snap fit within the front face of the bore of the jet receptor 30. Finger adjustment causes the eyeball 50 to swivel about its axis thereby altering the output direction of the air/water jet.

\\melb~fies\homeS\MCooper\Keep\Speci\PQ6951 BERRY MCNAB-CAP.doc 17/04/01 6 A venturi conventionally comprises a converging nozzle which is defined by the forward end 9 of the jet tube 31, a mixing chamber that is defined by the interior of the jet tube receptor 30 that surrounds the end of the jet tube 31 and is in communication with air drawn into the assembly via an air port 8 that forms part of the housing 7 as shown in Figure 5. The venturi also includes a throat which is in the form of a slightly diverging passageway that is defined by the internal bore 53 of the eyeball.

In the embodiment of this invention illustrated in the accompanying drawings, the nozzle or jet tube 31 has a elongate plenum chamber 70 supported centrally of the tube at the forward end 9 by three equally spaced radially vanes 82, 83 and 84. The plenum chamber has an open mouth 71 and an interior that tapers to a point 72 at the rear of the chamber. Each vane comprises a wall structure of :hollow construction defining an air passageway 85 that extends radially from the wall of the jet tube 31 to the 20 interior of the plenum chamber 70. The thickness of the wall structure of each vane 82, 83 or 84 tapers outwardly downstream of the assembly so that the wall structures operate as vanes. The vanes operate to straighten the flow of water entering the jet tube which as can be seen from Figure 5 comes in radially from an associated water pipe that forms part of the housing 7. The radial entry of the water causes a rotational force and the three vanes 82, 83, and 84 straighten the radial component of movement of water as it flows through the jet tube. The air passageways defined by the three vanes exit via elongate apertures 87, 88, 89 in the wall of the plenum chamber 70 so that air is drawn into the plenum chamber along a substantial part of its length at three equally spaced positions around the periphery of the chamber 70. The mouth 71 of the chamber 70 terminates at the mouth of the jet tube as shown in Figure 1. In this manner air is drawn into the plenum chamber 70 via the radial wall structures of the vanes 82, \\melbfiles\home\MCooper\Keep\Speci\P06951 BERRY MCNAB-CAP.doc 17/04/01 7 83, and 84 to mix with the core of the water flowing through the jet tube. Thus the mass of water mixes with air both on the radial exterior from the air drawn from the mixing chamber and on the interior via the plenum chamber 70 and the internal wall structures described above.

Thus, the surface area of the water that is subject to air contact is substantially increased which increases the aeration of the water and has the effect of increasing the efficiency of the jet by providing a more aerated effect without the need for additional power. By increasing the air/water ratio, a superior massage effect is created. An additional benefit is a reduction in load requirement on the pump. This allows more jets for a given 15 pump size. A conventional jet-venturi typically 8mm diameter, has an outer circumference of 25.1mm. The outer diameter of the jet nozzle discharge is the high velocity region where the air is induced or entrained into the water jet stream. The larger the circumference for a given velocity, the more air is entrained. By increasing the nozzle diameter the area of the entrainment region can be increased. However, this also increases the cross sectional area of the nozzle (which increases by the diameter squared) and consequently the mass of water required to drive the jet increases proportionally. Hence, the pump power requirement increases.

The new venturi arrangement described above has an outer diameter of 12mm, an inner diameter of 7mm with the three radial vanes 82, 83, 84 producing six radial edges of length 2.65mm. The physical arrangement results in a linear length of 58.74mm where the high velocity jet stream can induce or entrain the incoming air. By increasing the surface area of contact, without increasing the mass or volume of water, a higher induced air-flow can be generated without increasing pump power.

\\mebfies\home\MCooper\Keep\pei\PQ6951 BERRY MCNAB-CAP.doc 17/04/01 8 The dimensions discussed above are typical for the pressures and flows used in the spa application. It is understood that these dimensions would vary in other applications with other fluids, pressures and rates of flow.

Although the jet assembly and venturi are described for use with pool or jet spa assembly, it is understood that the venturi can be used in many other applications. Venturis are used in fields such as jet pumps where instead of mixing air with water, two fluids are mixed. Often these fluids are the same but merely at different pressures and velocities. Thus, it is understood that the venturi that is described above is equally 15 applicable to many other situations where fluids have to be intermixed with the use of minimum power.

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Claims

1. A venturi adapted to mix fluids comprising a converging nozzle having a mouth joined to a throat via a mixing chamber, the converging nozzle being arranged to be coupled to a first fluid to, in use, accelerate said fluid through the nozzle to exit the mouth as a jet stream, the mixing chamber being adapted to be coupled to a source of second fluid which mixes with the jet stream in the mixing chamber to leave the throat as a mixture of fluids characterised in that means is provided upstream of the mixing chamber to additionally introduce the second fluid within the jet stream of the first fluid.

2. The venturi according to claim 1 wherein the means is positioned within the nozzle to introduce the *i second fluid to the centre of the jet stream. *0

3. The venturi according to either claim 1 or claim S. 20 2 wherein the means comprises a plenum chamber having a mouth and a closed end, the chamber being supported substantially centrally of the nozzle with the closed end upstream of the flow, at least one conduit extending from the plenum chamber to the exterior of the nozzle to introduce the second fluid to the plenum chamber.

4. The venturi according to claim 3 wherein the plenum chamber is tapered to diverge outwardly downstream .of the nozzle, the mouth of the plenum chamber being at the mouth of the nozzle.

The venturi according to claim 4 wherein the plenum chamber is supported by at least two radially extending vanes, each vane being hollow to act as the fluid conduit.

6. The venturi according to claim 5 wherein the \\melb_files\home$\MCooper\Keep\Speci\PQ6951 BERRY MCNAB-CAP.doc 6/04/04 10 chamber is supported by three radially extending vanes equally spaced around the chamber.

7. The venturi according to either claim 5 or claim 6 wherein each vane tapers outwardly downstream of the venturi.

8. The venturi according to any one of claims 5 to 7 wherein the vanes act as means to straighten out rotational forces that the first fluid may possess as it flows through the nozzle.

9. The venturi according to any one of the preceding claims wherein the first fluid is water and the second fluid is air. I

10. A mixing jet assembly for use in a swimming pool or spa incorporating a venturi in accordance with any one of the proceeding claims.

11. A venturi substantially as described herein with reference to and as illustrated in the accompanying drawings. *o 25

12. A mixing jet assembly substantially as described herein with reference to and as illustrated in the accompanying drawings. Dated this 6 day of April 2004. DESMOND JOHN BERRY and ROBERT KENNETH MCNAB By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia \\melb_files\home$\MCooper\Keep\Speci\PQ6951 BERRY MCNAB-CAP.doc 5/04/04