AU2302601A - Air-swirl impingement cooling nozzle - Google Patents

Description

Z-ul ;1 :24 ;61 3 93479994 6/ 61 3 93479994 Regulation 3.2 -1-

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT APPLICANT: SPRAY NOZZLE ENGINEERING PTY. LIMITED

NUMBER:

FILING DATE: Invention Title: AIR-SWIRL IMPINGEMENT COOLING NOZZLE The following statement is a full description of this invention, including the best method of performing it known to me: RECEIVED TIME 9- FEB. 16:24 PRINT TIME 10. FEB. 11:12 -U 1 16:24 ;61 3 93479994 7/ S61 3 93479994 -2- AIR-SWIRL-IMPINGEMENT COOLING NOZZLE Area of the Invention This invention relates to cooling nozzles and in particular to cooling nozzles of the type in which air atomizes a cooling fluid and the resulted air/coolant mixture is ejected from the nozzle and caused to impinge upon a surface which is to be cooled.

Background to the Invention Such nozzles are discussed in the specification of US patent number 4,511,087 of Kyoritsu Gokin Manufacturing Co. Limited.

This specification describes two different types of nozzles which atomize liquid, one being a type in which the liquid is pressurized and passed through a nozzle and the other being a type where the liquid is entrained in air in the nozzle and the liquid/air mixture is expressed therefrom.

It is to the second form of such nozzles that the patent relates and it is to this form of nozzle too that the present application relates.

As is described in US patent number 4,511,087 there is a desiderata of nozzles of this type that the liquid be dispersed as evenly as possible in the airflow and the size of the droplets be small. This provides even distribution of the liquid onto the surface to which it is being applied, and where it is being used in a cooling application, the liquid has a substantial surface area per volume which partially enables evaporation to be effected quickly making maximum benefit of the latent heat contained in the liquid and, at the same time, the smaller the particles the less likely they are to rebound from the surface and thus be wasted as a cooling fluid.

K:\WP51\SPEC\SprayNozcap.wpd 9/2/0] RECEIVED TIME 9. FEB. 16:24 PRINT TIME 10. FEB. 11:12 9- 2-01;16:24

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;61 3 93479994 8/ 61 3 93479994 Outline of the Invention It is a principal object of the present invention to provide a nozzle apparatus for atomizing a liquid which operates more effectively than previously known nozzles.

The invention includes a nozzle apparatus for atomizing a liquid of the type where the liquid is caused to enter a chamber in the nozzle where it is struck by air to cause atomization and entrainment thereof, said nozzle including a nozzle head and delivery tube comprising the chamber and being provided with means to cause rotary motion of the air about a central axis of the nozzle to cause effective mixing of the liquid with the air.

The invention also includes a nozzle of this general type in which the fluid being passed into the chamber is caused to impinge upon a surface in the chamber to cause initial breaking up of the liquid into droplets.

In order that the invention may be more readily understood we shall describe one specific embodiment of the invention by way of non limiting example by reference to the accompanying drawing.

Brief Description of the drawing Figures Fig. 1 Fig. 2 Fig. 3 Shows a cross-section through an invention; embodiment of the nozzle of the is a perspective drawing of the pintle member; is a cross-section through the water ducts; head of the nozzle showing the air and A\SPEC\SprayNozzcap.wpd RECEIVED TIME 9. FEB. 16:24 PRINT TIME 10. FEB. 11 :12 -u ;I0:24 61 3 93479994 9/ 61 3 93479994 -4- Figure 1 shows the nozzle of the invention 10,which has a central bore 11 through which the fluid, hereinafter referred to for convenience as water, passes into a mixing chamber 12 or supply tube.

The arrangement of the liquid delivery differs from that of the previous known nozzles in that the liquid as it is passed into the tube 12, strikes a pintle 20 in the form of a disc coaxial of the tube and forward of the position of liquid delivery 21. The liquid striking this pintle tends to be dispersed outwardly in droplets or thin sheets.

The liquid, as shown in Figure 3, enters the side of the tube and enters the central bore 11 at right angles.

The gas referred to herein as air enters the head 15 of the nozzle at 16 and passes through ducts 17 to an annulus 43 of the pintle member 40 and passes through diagonally oriented channels 42 in the annulus so that the air which emerges is rotary in nature and spinning about axis 24. It is envisaged also that the air when passing through the chamber surrounding the water delivery means and the exterior wall of the nozzle, may be caused to rotate by the location of vanes or the like therein if preferred.

The air is delivered through a reduced portion 23 which has a frusto-conical outer S surface so that the air, on entering the tube, tends to be directed inwardly towards the axis of the tube and in fact towards the pintle 20 which is struck by the liquid.

In this arrangement there is a double action on the water, it tends to be dispersed by striking the pintle, and at the same time, it is struck by the air causing rapid and effective atomization. A lip 25 inside tube 12 at the air outlet helps prevent the mixed air and water re-entering the frusto-conical section 23.

The arrangement in delivery has two effects. Firstly, it tends to ensure that the air delivered around the periphery is effectively at the same volume and pressure about the periphery and secondly, the form of movement aids in ensuring that the water is broken K:\WP51\SPEC\SprayNozzcap.wpd 9/2/01 RECEIVED TIME 9. FEB. 16:24 PRINT TIME 10. FEB. 11:12 U- -U1 16:24 ;61 3 93479994 10/ 61 3 93479994 into small droplets which are carried by the air in this swirling motion so as, again, to ensure even distribution thereof.

The mixed air liquid drops pass down the delivery tube 12 which is of a sufficient length that the swirling droplet/air mixture becomes quite homogenised. It is then ejected through a nozzle aperture 30 which may have a smoothly formed inner surface and which may be of different formation depending upon the required distribution of the material leaving the nozzle.

For example, we could provide a flat spray forming a flat wide band of material being sprayed or a full conical spray head or other form of spray pattern.

For example, the aperture through the nozzle could be of a frusto-conical form having the larger diameter in at the outlet of the nozzle so that there will tend to be a relatively wide dispersement of the material leaving the nozzle. Alternatively, the aperture could have a relatively cylindrical form so that the material leaving this is delivered in a relatively small stream with the material in this stream being largely a homogeneous mixture of the air and the water.

oo One exemplary application of a nozzle of the invention is to cool steel or the like after it passes through sizing rollers and in this application it is required that as much benefit be gained as possible of the latent heat of the liquid, in this case water, being sprayed thereon, the spray being relatively even so the cooling of the sheet is effectively uniform.

The nozzle must be adapted to be able to have a good working life at relatively high temperatures.

o The nozzle of the invention provides all of these desiderata.

The nozzle can be used in other applications, such as gas cooling an precipitation of solids from gasses, as used in pollution control applications or to distribute fungicides K:\WP51\SPEC\SprayNozzcap.wpd 9/2/01 RECEIVED TIME 9. FEB. 16:24 PRINT TIME 10J EB, 11:11 S, 4 ;61 3 93479994 11/ 61 3 93479994 -6or insecticides or other applications where a fine dispersion which is basically uniform is required.

We have described in the foregoing one particular form of nozzle but it is to be understood that variations can be made in this depending upon the required output from the nozzle. For example, the actual form of chamber in which the air is caused to move can be modified as can the outlet from this to provide a required form of airflow.

Also, we have described the pintle as being in the form of a disc and whilst this may be a desirable feature in some application, if a more disturbed flow is required some other shape could well be used.

It is also possible to incorporate an air-flow straightener so that the swirling motion os re-directed straight down the tube for applications where the gas is to be directed directly forward of the nozzle orifice to be emitted in a particular form.

It is also possible to provide a spiral or helicoidal nozzle at the outlet as well as a nozzle which has a full conical distribution pattern.

9* In some applications, the connections of the liquid and the gas can be reversed to provide required properties of the outlet.

i We have not described the materials of construction or the particular formation of the nozzle of the invention, the materials would be those commonly used in the art and the actual formation could be caused to vary substantially depending on the use to which the nozzle is to be put and the characteristics of the nozzle output required.

All such modifications are deemed to be within the spirit and scope of the invention.

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Claims (7)

1. A nozzle apparatus for atomizing a liquid of the type where the liquid is caused to enter a chamber in the nozzle where it is struck by air to cause atomization and entrainment thereof, said nozzle including a nozzle head and delivery tube comprising the chamber and being provided with means to cause rotary motion of the air about a central axis of the nozzle to cause effective mixing of the liquid with the air.

2. A nozzle as claimed in claim 1 in which the fluid being passed into the chamber is caused to impinge upon a surface in the chamber to cause initial breaking up of the liquid into droplets.

3. A nozzle as claimed in claim 2 in which the air is caused to move in a rotary fashion by being passed through at least one diagonally oriented channel in a head of the nozzle to a mixing chamber or delivery tube of the nozzle.

4. A nozzle as claimed in claim 3 wherein the air after passing through a diagonally oriented channel in the head of the nozzle, passes through an aperture prior to entry in the delivery tube which aperture has a reduced exit portion and which aperture is shaped to direct the air towards the axis of the delivery tube.

5. A nozzle as claimed in claim 4 wherein the aperture is substantially frusto-conical in shape.

6. A nozzle as claimed in any one of claims 1 to 5 wherein a lip is provided within the nozzle where the air enters the delivery tube to minimise the possibility of air and water droplets re-entering the nozzle head. K:\WP51\SPEC\SprayNozzcap.wpd 9/2/01 RECEIVED TIME 9. FEB- 16:24 PRINT TIME 10. FEB. 11:11

9- 2-01; 16:24 rk. ;61 3 93479994 13/ 61 3 93479994 7. A nozzle as claimed in any one of claims 1 to 6 wherein water enters the nozzle head through an aperture in the side of the head and passes to the delivery tube through a central channel orthogonal to the aperture. 8. A nozzle as claimed in claim 2 in which the surface is a disc suspended from the nozzle head into the delivery tube. 9. A nozzle substantially as hereinbefore described with reference to the accompanying drawings. DATED this 9 day of February, 2001 SPRAY NOZZLE ENGINEERING PTY. LIMITED By Its Patent Attorneys A TATLOCK ASSOCIATES C. 9* K:\WPS1\SPEC\SprayNozzcap.wpd RECEIVED TIME 9, FEB. 16:24 PRINT TIME 10. F EB. 11 :11