AU2018222911B2

AU2018222911B2 - Spray nozzle

Info

Publication number: AU2018222911B2
Application number: AU2018222911A
Authority: AU
Inventors: Vitold Ronda
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-11-14
Filing date: 2018-08-28
Publication date: 2021-10-07
Anticipated expiration: 2038-08-28
Also published as: AU2020102810B4; AU2020102810C4; AU2018222911A1; AU2020102810A4

Abstract

A nozzle housing for a multiple orifice spray nozzle comprising a cylindrical body with a liquid inlet end with a base section with two or more liquid spray nozzle ports for removeably receiving at least one liquid spray nozzle, the liquid nozzle spray ports being in liquid communication with the liquid inlet, an open liquid outlet end such that liquid sprayed from at least one spray no the base section passes through the cylindrical body towards the liquid outlet end and the cylindrical body comprises at last two radially angled air inlet holes for introducing air into the liquid spray. Figure 1 1/6 42 44 18 10 30 6 34 12 22 20 14 1 Figure 1 48 32 16 1414 10 -48 -- F12i~~~e12 Figure 2 Figure 2a

Description

1/6

42

44 18 10

30 6 34 12

20 22

1 14 Figure 1 48 32

16

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Figure 2 Figure 2a

SPRAY NOZZLE FIELD

The present disclosure relates to a spray nozzle for delivering a spray mist at relatively high velocity.

BACKGROUND

The use of water mist sprays has wide applications in dust suppression systems, evaporative cooling and fire protection systems.

Generally, the first component selected in the design of a spray mist is the nozzle type which is selected based on droplet size, spray penetration, mist density, spray angle, and droplet velocity. These are all a function of spray nozzle design and input conditions (e.g. water pressure). The aspect of a nozzle's performance most important to its effectiveness in these applications is droplet size.

For example, in dust suppression systems, as both a droplet and a dust particle travel through the air, both will impart a force on the air which will alter their motion and effect their interactions with each other. If a very small object is travelling towards a larger object, the fluid flowing around the large object will impart a force on the small object causing it to become entrained in the disturbed air and travel around the object rather than impacting with it. The greater the difference in size the more pronounced this effect will be and as such the less likely it is that impact will occur. Based on this explanation it can be concluded that to maximise the potential of dust capture by water droplet it is most important to have droplets of comparable size to the dust particles being captured. Furthermore, as well as having droplets of comparable size, it is also necessary to have droplet concentration or mist density greater than the concentration of dust in the air such that all the dust can be captured.

Dust suppression systems are used in any application where respirable dust is generated. Respirable dust is generally considered to be particles less than 100 pm that can be inhaled and retained in the lungs. Long term exposure to respirable dust can cause long term health effects. An example is black lung disease caused by inhalation of respirable coal dust. It follows that droplet size for dust suppression systems.

Water mist systems for use in indoor fire protection systems is becoming more preferable over conventional sprinkler systems. Water mist systems deliver fine water sprays of small droplets of between about 100 pm and 200pm. These systems are very efficient in controlling fires.

Water extinguishes fires by vaporisation to steam that results in a dilution of oxygen and fuel vapours together a cooling effect as a result of conversion of water to steam. If sufficient heat is withdrawn from the hot gases and flame, the temperature may be dropped below that necessary to sustain combustion.

A spray with a fine droplet size has a significantly increased surface area for heat absorption and evaporation when compared to smaller droplet size and enhances the speed at which the spray extracts heat.

Another advantage of the water mist spray system is that all water is evaporated and avoids water damage that occurs using conventional sprinkler systems. Another advantage is that significantly less water is required to supress a fire.

However, there is a compromise between droplet size, susceptibility to drift and cross winds and reach. This has limited use of spray mist fire suppression to enclosed areas. It will be appreciated that use of a fine mist that is subject to cross wind drift would not be suitable for a bush fire or wild fire that are generally fed by wind and updraft generated by the heat of the fire.

There are broadly two types of atomising nozzles, hydraulic nozzles and ait atomising nozzles or two fluid nozzles. Hydraulic nozzles rely upon the internal energy of the liquid being sprayed to atomise the fluid into droplets and form the spray pattern. Higher fluid pressures increases the overall internal energy of the fluid. Most of the internal energy of the fluid is consumed by breaking up the liquid into droplets and there is very little left to project the droplets forward.

Thus although small size droplets from hydraulic nozzles may have a high initial velocity, this diminishes quickly, such that they do not travel far. Fine drop sizes are also particularly susceptible to turbulence or cross winds. This can be disadvantageous in underground mines where mine ventilation, particularly in those areas where high levels of dust are generated. Susceptibility to turbulence and cross winds, limits water mist fire protection systems to enclosed areas.

Air atomising nozzles, on the other hand, impact compressed air into the fluid to break the fluid into fine droplets, and to project the droplets forward. Small droplet sizes may be projected by the compressed air further than a spray from a hydraulic nozzle and at much lower water pressure.

However, in some applications it is not practical to have a source of compressed air.

It would be desirable to provide a spray nozzle and spray nozzle housing therefore that may provide an alternative to currently available spray nozzles.

SUMMARY

In one aspect, there is disclosed a nozzle housing for a multiple orifice hydraulic spray nozzle comprising a cylindrical body with a liquid inlet end configured in use for receiving a liquid under pressure with a base section with two or more liquid spray nozzle ports for removeably receiving at least one liquid spray nozzle, the liquid nozzle spray ports being in liquid communication with the liquid inlet, an open liquid outlet end such that liquid sprayed from at least one spray nozzle received within the base section passes through the cylindrical body towards the liquid outlet end and the cylindrical body comprises at last two radially angled air inlet holes for introducing air into the liquid spray.

Suitably, the base section comprises at least three spray nozzle ports, with one port located centrally. The other ports may be spaced radially and suitably equidistant.

Thus in one aspect, there may be five nozzle ports, one central port and four radial ports defining an angle of 90° apart.

In another aspect, there may be seven nozzle ports, one central port and six radial ports defining an angle of 72° apart.

In a further aspect, there may be nine nozzle ports, one central port and eight radial ports defining an angle of 45° apart.

The nozzle ports can removeably receive a spray nozzle.

The nozzle ports may also removeably receive one or more nozzle port plugs so as to allow for customisation of the outlet.

It will be appreciated that different nozzle configurations can be used depending on the requirements of the specific application including control of the number of nozzles and nozzle orifice sizes. This allows the spray coverage, droplet distribution and water consumption to be optimised for specific applications.

The outlet end of the cylindrical body has at least two radially angled air inlet holes. By radially angled is meant that the angle of the inlet hole axis is at an angle to the radius of the chamber defined between the centre of the chamber and the axis of the hole on the outer wall. Suitable angles are between about 10° to about 30°, more suitably about 20°.

The inlets draw air into the cylindrical body and creates a swirling motion in the spray from the nozzles. This further breaks up the spray from the nozzles without absorbing kinetic energy from the liquid, thereby improving reach of the spray.

Further, as multiple nozzles can be employed with different orifices, the nozzle configuration may be optimised to improve reach and reduce drift. An example configuration may consist of a relatively large orifice nozzle delivering a spray with a droplet size of between about 100 pm to about 400 pm in the centre and small orifice nozzles delivering a spray with a smaller droplet size of up to about 50 pm t o 200 pm around the outside. This would allow the spray to penetrate a large distance due to the inner large orifice nozzle whilst still maintaining fine droplets due to the outer small orifice nozzles.

Also disclosed herein is a multi orifice spray nozzle comprising the spray nozzle housing as disclosed herein and at least two spray nozzles mounted thereto

Suitably, the multi-orifice spray nozzle comprises liquid inlet housing is fluidly connected to a liquid supply by means of a liquid inlet housing. The liquid inlet housing suitably has a base with a single liquid inlet for connection to a fluid supply at the inlet end thereof, the liquid outlet chamber having a base defining an outlet end wall of the inlet housing.

The liquid inlet member suitably has a cylindrical body having an internal bore with an inlet end and an outlet end.

The internal bore is suitably stepped outwardly from the inlet end to the outlet end.

In one aspect, the stepped bore of the inlet housing has three step sections, a first inlet bore section having afirst diameter, a second outlet bore section having a second diameter larger than the first diameter and an intermediate bore section having a diameter intermediate the first diameter and the second diameter.

The nozzle housing may have a collar depending from the outlet end of the nozzle housing and the collar has bores for receiving the inlet end of a respective spray nozzle body and the step between the intermediate bore section and the outlet bore section forms a seat for the terminal end of the collar.

Suitably, the collar may have an external thread for being threadably received within the outlet bore of the inlet housing.

In this case the intermediate bore section serves as a manifold for feeding liquid to the respective spray nozzles of the spray nozzle housing.

Suitably, the operating pressure of the multi-orifice spray nozzle is between about 5 bar to about 350 bar, suitably between about 100 bar to about 300 bar.

It will be appreciated that operating pressure may be determined by a number of factors such as desired droplet size, mist profile, reach and cross wind.

Suitably the nozzles are a pressure swirl type of nozzle.

In one aspect the nozzles are a modified pressure swirl nozzle having an enclosed section surrounding the spray exit that creates a low-pressure zone adjacent to the spray. There are air inlets at the nozzle exit. These inlets draw air into the nozzle and create a swirling motion in the spray that enhances liquid breakup resulting in a greater concentration of fine droplets as well as improved dispersion and velocity. The nozzle housing consists of several more air inlets. These inlets entrain more air into the spray.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a perspective exploded view of a spray nozzle as disclosed herein;

Figure 2 is a perspective view of the spray nozzle;

Figure 2a is the nozzle of Figure 2 in which the two parts are welded together;

Figure 3a is a plan view of the spray nozzle housing;

Figure 3b is a cross section of the housing showing the air inlet holes;

Figure 3c is a plan view of the housing showing one example of a nozzle configuration;

Figure 4 is a side view of the housing showing the nozzle ports and inlet in phantom;

Figure 5 is a plan view and cross section of the liquid inlet housing;

Figure 6 is a top perspective view of the inlet housing;

Figure 7 is a cross section of the spray nozzle;

Figure 8 is a cross section of a nozzle as shown in Figure 1;

Figure 9 is a graph of water consumption of various nozzles of the type shown in Figure 8, when a single nozzle is fitted to the spray nozzle housing; and

Figure 10 is a graph showing velocity against distance for a single nozzle of the type shown in Figure 8 when fitted to the spray nozzle at different pressures.

DETALED DESCRIPTION OF THE FIGURES

Figure 1 is an exploded view of a multi-orifice spray nozzle 10 of one aspect of the disclosure. The spray nozzle 10 has a liquid inlet housing 12 and a spray nozzle housing 14. The liquid inlet housing 12 has a cylindrical body 20 terminating in an open upper end 22. The liquid inlet housing 12 has a base 16 with a single liquid inlet 17.

The liquid nozzle housing 14 also has a cylindrical body 18 with a base section 30 with an extending collar 32. The base section 30 has nine nozzle ports 34 (more clearly seen in the plan view of figure 3). There is a central nozzle port 34c and 8 nozzle ports equally spaced towards the circumference of the liquid outlet chamber. The nozzle ports 34 have a screw thread for threaded connection with a spray nozzle 42 or a plug 44. This allows a user to change nozzle configuration as desired in response to different applications and conditions.

The spray nozzle housing 14 has 5 air four inlet holes 48 spaced equally about the body 18. The air inlet holes 48 pass through the wall of the body 18 at an angle a of about 20° to the intersecting radius as shown in Figure 3b.

The inlets 48 draw air into the nozzle housing 14 and create a swirling motion in the spray that enhances total liquid breakup up of spray produced by all nozzles. This results in a greater concentration of fine droplets as well as improved dispersion and velocity.

Figures 3a, 3b and 3c show top plan views and a cross section of the top plan view showing the location and angle of inclination of the air inlet holes 48 and an example configuration of nozzles 42 and plugs 44.

The base section 30 of the spray nozzle body 14 has an extending collar 32 into which the nozzle ports 34 extend as may be seen in figures 4 and 7. The collar 32 has an external thread.

As can be seen in figures 5, and the liquid inlet 17 in the inlet housing base 12 has a stepped bore 50. The stepped bore 50 has three step sections, a first inlet bore section 51 having a first diameter, a second outlet bore section 54 having a second diameter that is larger than the first diameter and an intermediate bore section 56 having a diameter intermediate the first diameter and the second diameter.

The intermediate bore section 56 has an internal thread for threadingly receiving collar 32 so as to join the spray nozzle housing 14 to the inlet housing 12. The threaded connection is for ease of manufacture. In practice, the two parts 12, 14 will welded together so as to resist the high operating pressures. Suitably the weld is machined such that the weld line cannot be seen as shown in Figure 2a.

Figure 7 shows the two parts 12, 14 connected together and how the inlet end of the collar 32 is seated on the seat 58. It may also be seen in figure 7 that the intermediate bore part inlet 17 can feed liquid to all 9 nozzle ports 34.

Figure 8 is a cross section of a preferred nozzle 60 for use with the spray nozzle.

The nozzle 60 is based upon the general concept of a pressure swirl type nozzle.

A pressure swirl nozzle traditionally consists of a swirl plate and swirl chamber fed by angled liquid inlets. The purpose of the swirl plate is to create rotational motion of the liquid stream that assists with droplet breakup and distribution as it exits the swirl chamber outlet nozzle orifice.

The design of the nozzle 60 in figure 8 has a swirl plate 64 and a swirl chamber fed by angled liquid inlets 64 as per conventional swirl nozzle. However, the nozzle 60 has an additional enclosed chamber section 70 surrounding the swirl chamber outlet orifice 68 that creates a low-pressure zone adjacent to the spray 72 from the orifice 68.

Air inlets 74 introduce air into chamber section 70. The comparably high-pressure air outside the nozzle 60 is drawn in. These inlets 74 draw air into the nozzle 60 and create a swirling motion in the spray that enhances liquid breakup resulting in a greater concentration of fine droplets as well as improved dispersion and velocity.

Figures 9 and 10 are graphs showing water consumption and mist velocity for a nozzle of the type shown in figure 8 when fitted to a spray nozzle as disclosed herein.

As discussed above, the nozzle housing consists of several air inlets. These air inlets entrain more air into the spray, using the same mechanism described earlier, as it further develops out of the nozzle and thus increasing the desirable affects noted earlier. It will be appreciated that at high pressure and nine nozzle sprays, that the effect of the entrained air in breaking up the spray further and introducing kinetic energy to the droplets may be significant.

The disclosed spray nozzles may find particular application in any suitable dust suppression spray system. Dust suppression spray systems are used in underground coal mines to protect miners from respirable dust. Dust suppressions systems are also used when transferring particulate material to ship holding containers, other material handling sites and stock piles. The spray nozzles can deliver a spray with small droplets at high pressure that avoids the requirement of a compressed air supply. Further, the nozzle can deliver a high concentration of droplets. It is important for dust suppression that not only are the droplets of comparable size of the dust particles, that the droplet concentration is greater than the particle concentration. Still further, the spray is delivered with sufficient velocity that the droplets are much less susceptible to drift when compared with conventional hydraulic nozzles.

Still further, the spray nozzle can be tailored for a specific application by using different nozzles and configurations thereof.

Another application for the spray nozzles as disclosed herein is in firefighting and in particular rural fire fighting where a water supply is carried on a fire tanker or pump. Outdoor fires are generally sprayed with a straight spray of water at pressures generally below 35 bar. The seat of the fire is sprayed and subsequent vaporisation of the water reduces oxygen availability and has a cooling effect.

The water is sprayed at a flow rate of between about 1000 litres per minute to about 3500 litres per minute. It will be appreciated that tank capacity can significantly limit the effective fire fighting time of a fire tanker or pump. Vaporisation efficiency is dependent upon droplet size that in turn is dependent upon pressure. At conventional firefighting water pressures and nozzles, the droplet size is in the order of about 1000 pm. Smaller droplets have a significantly larger surface area that enables faster and more efficient cooling. Further the smaller droplets are completely vaporised, thereby allowing water flow rates to be significantly reduced. As shown above in figure 7, flow rates of nozzles suitable for use in the spray nozzle of the present disclosure have flow rates of between about 1 L/min at 100 bar to about 24L/min at 300 bar. With nine nozzles, the water flow rate would be between about 9 L/min to about 216 L/min.

Still further, smaller droplet sizes will travel further in the air, thereby having a greater reach. However, as discussed in the introductory section, this smaller size means that conventional mists from hydraulic nozzles have little kinetic energy, low velocity and a highly subject to deflection from a crosswind. As can be seen from Figure 8, a nozzle mounted to the spray nozzle disclosed herein has an initial velocity of between about 30 m/s at 100 bar to about 40m/s at 160 bar and therefore are less subject to cross wind deflection.

It may be appreciated that the spray nozzle as disclosed herein may be used for any suitable application where the spray mist may be subject to a crosswind or other wind current.

It will be appreciated that various changes and modifications may be made to the invention as disclosed and claimed herein without departing from the spirit and scope thereof.

Claims

1. A nozzle housing for a multiple orifice hydraulic spray nozzle comprising a cylindrical body with a liquid inlet end configured in use to receive a liquid under pressure with a base section with two or more liquid spray nozzle ports for removeably receiving at least one liquid spray nozzle, the liquid nozzle spray ports being in liquid communication with the liquid inlet end, an open liquid outlet end such that liquid sprayed from at least one spray nozzle received within the base section passes through the cylindrical body towards the liquid outlet end and the cylindrical body comprises at least two radially angled air inlet holes for introducing air into the liquid spray.

2. The nozzle housing of claim 1, wherein the liquid is water.

3. The nozzle housing of claim 1 or claim 2, wherein the base section comprises at least three nozzle ports.

4. The nozzle housing of claim 3, wherein one nozzle port is located centrally and the other nozzle ports are spaced radially and equidistant from each other.

5. The nozzle housing of claim 4, comprising five nozzle ports, one central port and four radial ports defining an angle of 90° apart.

6. The nozzle housing of claim 4, comprising seven spray nozzle ports, one central port and six radial ports defining an angle of 72° apart.

7. The nozzle housing of claim 4 comprising nine spray nozzle ports, one central port and eight radial ports defining an angle of 4 5 ° apart.

8. The nozzle housing of any one of claims 1 to 6, wherein the nozzle ports have threads for threadingly receiving a spray nozzle or a nozzle port plug.

9. The nozzle housing of any one of claims 1 to 8, wherein the base section comprises a depending collar with threaded bores for receiving a threaded inlet end of a spray nozzle.

10. The nozzle housing of claim 9, wherein the collar has an external thread.

11. A multiple orifice spray nozzle comprising the spray nozzle housing of any one of claims 1 to 10, and aliquid inlet member fluidly mounted to the inlet end of the nozzle housing for fluid connection to a supply of pressurised liquid.

12. The multiple orifice spray nozzle of claim 11, wherein the fluid inlet member has a cylindrical body having an internal bore with an inlet end and an outlet end.

13. The multiple orifice spray nozzle of claim 12, wherein the internal bore is stepped outwardly from the inlet end to the outlet end.

14. The multiple orifice spray nozzle of claim 13 wherein the steppe bore of the inlet housing has three step sections, a first inlet bore section having a first diameter, a second outlet bore section having a second diameter larger than the first diameter and an intermediate bore section having a diameter intermediate the first diameter and the second diameter.

15. The multiple orifice spray nozzle of claim 14, wherein the nozzle housing has a collar depending from the outlet end of the nozzle housing and the collar has bores for receiving the inlet end of a respective spray nozzle body and the step between the intermediate bore section and the outlet bore section forms a seat for the terminal end of the collar.

16. The multiple orifice spray nozzle of claim 14, wherein the intermediate bore section serves as a manifold for feeding liquid to the respective spray nozzles.

17. The multi-orifice spray nozzle of any one of claims 1 to 11 comprising a central spray nozzle delivering a spray with a droplet size of between about 100 pm to about 400 pm.

18. The multi-orifice spray nozzle of claim 17, comprising radial spray nozzles delivering a spray with a droplet size of up to about 200pm.

19. The multiple orifice spray nozzle of any one of claims 11 to 18, where the liquid is water and the operating pressure of the water is between about 5 bar to about 350 bar.

20. The spray nozzle of any one of claims 11 to 19, wherein at least one nozzle is a modified pressure swirl nozzle comprising an enclosed chamber section surrounding the swirl chamber spray exit that creates a low-pressure zone adjacent to the spray exit and air inlets are provided in the enclosed chamber section.