AU2018220007A1 - Spray apparatus - Google Patents

Abstract

A spray apparatus 30 for dust suppression comprising an elongate housing 32 having a first side wall 38, a second side wall and a spray wall 34 having at least one spray exit hole 36. An elongate fluid conduit 60 is located within the housing. A least one spray nozzle 64 is fluidly mounted to the elongate fluid conduit 60 at a position such that a fluid sprayed from the spray nozzle will exit the housing through a spray exit hole 36. Figure 1 22 sr 2 Figure 10 li 38 31 li* 42 Figure 2

Description

A spray apparatus 30 for dust suppression comprising an elongate housing 32 having a first side wall 38, a second side wall and a spray wall 34 having at least one spray exit hole 36. An elongate fluid conduit 60 is located within the housing. A least one spray nozzle 64 is fluidly mounted to the elongate fluid conduit 60 at a position such that a fluid sprayed from the spray nozzle will exit the housing through a spray exit hole 36.

Figure 1

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Figure 2

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SPRAY APPARATUS

FIELD

The present disclosure relates to a spray apparatus. In particular, the present disclosure relates to a spray apparatus for dust suppression.

BACKGROUND

The reference to prior art in this specification is not and should not be taken as an acknowledgment or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia or in any other country.

Control of dust emission during material handling and transport and dust generated during mining operations is a recognized problem.

The present disclosure will place particular attention to the mining industry and in particular coal mining. However, it will be appreciated that the disclosed spray apparatus and methods may not necessarily be limited to use in the mining industry and no limitation is intended thereby.

Of particular concern in many industries including but not limited to mining, materials handling and transport is the control of respirable dust. Inhalation of respirable dust, particles having a particle size of 10 microns or less is known to create a number of health hazards, one of which is the risk of developing lung diseases. Coal miners are known to be at risk of developing coal workers’ pneumoconiosis or black lung disease. Many industrialized countries have set strict dust concentration standards, in order to protect worker’s health and mine safety. The permissible exposure limit (PEL) is the daily limit of exposure to a substance to humans is generally measured as a time weighted average (TWA) over and 8 hour work shift. The TWA for exposure for respirable coal dust (containing < 5% quartz) in Australia is 3 mg/m³ (according to s89 of the coal Mining Safety and Health Regulation 2001 (Cth) and 2.4mg/m³ (according to the Occupational Safety and Health Administration) in the United States.

Dust on longwall production faces has always been an issue of concern for health and safety of workers. Longwall mining is a method of underground mining where a wall of coal is mined in a single slice. The machine used to cut the coal form the coal face is known as a shearer. The shearer has a rotating drum that rotates in a plane parallel to the coalface. The drum is mounted to a ranging arm which is connected to the shearer body. The shearer is mounted on an armored face conveyer (AFC) which is used to carry the shearer along

2018220007 21 Aug 2018 the length of the face of a coal wall panel. In this way the shearer gradually removes the coal as it moves along the length of the panel, then loads the mined coal onto the AFC which transports the coal to the main conveyer system via the beam stage loader (BSL).

Hydraulic jacks known as shields, chocks or powered roof supports, support the roof of the coalface and advances as the shearer works through the panel of coal. As the chocks progress forward, the resulting unsupported roof behind the chocks is allowed to collapse.

The advancement of longwall mining technologies has led to an increase in productivity. This in turn has led to an increase in the dust produced. Controlling dust to within the PEL is an ongoing challenge to mine operators, and a subject of ongoing research.

Conventionally, dust is controlled by ventilation, scrubbers, engineering controls aimed at reducing dust generation, using water sprays for dust suppression or a combination thereof.

The shearers and chocks have been found to be the main source of dust on long wall faces. Water sprays are generally mounted at various positions on a shearer and also set up at the BSL discharge. As each mine is different, the number and positioning of the sprays varies from mine to mine and each mine has a dust mitigation set up that is effective for that particular operation.

Water sprays can suppress, capture and/or redirect dust away from operators, dependent upon the velocity, flow pressure, location and type of spray generated.

Generally, the first component selected in the design of a dust suppression system 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 at capturing dust is droplet size. 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.

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Mounting of these spray nozzles have generally be done in one of two ways, either multiple nozzles inside a solid block of material, referred to as a spray block, or single nozzles mounted one off out of a pipe or hose. Nozzle mounting is a critical issue as the mounting method can greatly affect the longevity of the nozzles. Nozzles used for dust suppression are often located in extremely harsh environments where large machinery, rocks, and other objects are moving around and can easily impact with the nozzles. If the nozzles are not securely mounted and protected they become damaged and either need to be replaced or simply become useless.

Spray blocks are manufactured by machining nozzle mounting holes and air inlet holes into a billet of material. This provides optimum protection for the nozzles from being impacted by flying rocks and debris in the harsh mine environment. However, this is a very costly and time-consuming approach. Billet material is expensive and the machining operations required to remove material away from the billet to provide the nozzle positions and the inlet air holes are complex. This approach also requires specific tooling/jigs to be developed for each individual spray block/bar that is produced, this limits flexibility and results in there generally being a one size fits all approach taken to reduce the cost associated with trying to manufacture several types for all applications.

It is therefore not possible to provide flexibility in spray block production so as to customise the spray for different applications and environments.

In the present description and claims, the term “comprising” shall be understood to have a broad meaning similar to the term “including” and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” and “comprises”.

SUMMARY

In a first aspect, there is disclosed herein a spray apparatus for dust suppression, the spray apparatus comprising;

an elongate housing having a first side wall, a second side wall and a spray wall having at least one spray exit hole therein, an elongate fluid conduit within the housing;

at least one spray nozzle fluidly mounted to the elongate fluid conduit at a position such that a fluid sprayed from the spray nozzle will exit the housing through a spray exit hole.

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Suitably the elongate fluid conduit is formed from a material that can be easily machined to allow for different types of spray nozzles to be mounted to the conduit and to also vary the spacing between the spray nozzles. This allows for flexibility of design that is not possible with conventional spray blocks.

Suitably, the housing is able to provide at least some protection for nozzles housed within from falling rock and debris.

Suitably, the housing is modular in construction to allow for ease of manufacture.

Suitably, the housing has a first elongate member and a second elongate member that can be engaged to define the housing.

Suitably, the first and second elongate members are U shaped metal bars having opposed flanges connected by a web.

Suitably, the respective webs form the first and second side walls of the housing when they are engaged. In this case, the spray wall is defined by the abutting flanges of the respective elongate members. Suitably, the abutting flanges have a profile having spaced and opposite hemispherical recesses that when the flanges abut, define the spray exit holes.

Suitably, the spray apparatus comprises at least one mounting member for mounting the spray apparatus to a support. In one aspect, the support may be various parts of a shearer used in longwall coal mining operations.

Suitably the spray nozzles of the spray apparatus are of the type having an air inlet for allowing air to become entrained with the fluid so as to optimise droplet formation and velocity. In this arrangement the housing will further comprise at least one air inlet for allowing air into the housing.

The U shaped metal bars can easily be machined to provide tailored configurations of air inlets, mounting bars and nozzle mountings.

In one aspect, the spray apparatus may comprise at least one spray nozzle that produces a spray having first droplet particle size distribution over a first spray area and a second nozzle that produces a spray having a second droplet particle size distribution and the spacing between the at least first nozzle and the at least second nozzle is predetermined such that there is at least some overlap of the first spray area and the second spray area.

This arrangement allows for the particle sizes to be combined so as to provide a broader droplet distribution of size so as to capture a broader range of dust particle sizes.

It will be appreciated that there may be considerable different ranges and types of dust particle size distribution between different mines, different ventilation systems, different machinery, different grades of material being mined and many other variables.

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Further, the combination of different nozzles and the distances between them can be arranged in such a way that high velocity large droplet sprays can be used to help carry the smaller more effective droplets further towards the area that is being treated improving the performance of the overall system.

Thus the disclosed spray assembly provides the flexibility to tailor a spray solution to specific circumstances, allowing optimisation of dust suppression. This can provide a significant advantage in terms of workplace health and safety.

According to a further aspect of the disclosure, there is provided, a method of supressing dust at a location, comprising;

assessing dust level values and particle size values at a location;

calculating from the assessed values, a desired droplet particle size distribution, volume and particle velocity; and selecting spray nozzles to provide the desired spray droplet particle size distribution and manufacturing a spray apparatus as disclosed herein with the selected spray nozzles and mounting the spray apparatus at the location.

Methods of assessing dust parameters can easily be carried out by persons of skill in the art and is in fact required to be done as part of work and safety compliance.

Another area where dust suppression is required but only on a temporary basis is during loading and unloading of dust containing or generating materials from transporters such as ships, trucks and railcars and also storage containers. It is known to provide temporary dust suppression spray systems within dry bulk cargo containers such as a hold of a ship. Such systems have a series of spray bars that are temporarily mounted to the side of the container for dust suppression during loading of the dry bulk cargo into the container. Setting up dust suppression systems in a container takes time, man power and thus cost. Generally spray bars are suspended or otherwise mounted to the top or walls of the container.

It is considered desirable to be able to provide an alternative method for mounting a spray apparatus within a dry cargo container.

Also disclosed herein is a dust suppression system for use in a container having a ferromagnetic surface part for a dry bulk material comprising;

at least one elongate fluid conduit having a plurality of fluid spray nozzles fluidly mounted thereto;

a fluid supply fluidly connectable to the at least one elongate fluid conduit;

at least one magnet that is switchable between a magnetic state and a nonmagnetic state and in use can magnetically engage and disengage a ferromagnetic surface part of the container; and

2018220007 21 Aug 2018 a connector for connecting the elongate fluid conduit to a magnet.

The mounting system uses a switchable magnetic for mounting the fluid conduit or spray bars to the container. The magnet may be any suitable type of magnet such as an electromagnetic or switchable permanent magnet, the latter being preferred.

Typically, containers are fully constructed of a ferromagnetic material such as steel. It will be appreciated that the magnetic can therefore be mounted at any suitable location of the container without constraints of mechanical fastening methods.

The connector may be any suitable method of connecting a fluid conduit to a magnet. Suitably the connector is flexible such as a cable.

In one aspect, the system includes a mount for connecting the connector to the spray bar. Suitable the mount allows for removable connection such that the mounting position on the spray bar can be changed as desired to provide for flexibility in the system to be used with different size containers, different types of dry cargo and fill levels.

Suitably the mount allows for rotation of the bar relative to the mount to allow for spray angle of the spray nozzles to be varied.

Also disclosed herein is a spray apparatus for use in a container having a ferromagnetic surface part for a dry bulk material comprising;

at least one elongate fluid conduit having a plurality of fluid spray nozzles fluidly mounted thereto;

a fluid supply fluidly connectable to the at least one elongate fluid conduit;

at least one magnet that is switchable between a magnetic state and a nonmagnetic state and in use can magnetically engage and disengage a ferromagnetic surface part of the container; and a connector for connecting the elongate fluid conduit to a magnet.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a prior art spray block;

Figure 2 shows a spray apparatus as disclosed herein;

Figure 3 shows an exploded view of the spray apparatus as shown in Figure 2;

Figure 4 shows a nozzle and nozzle housing for use with the spray apparatus as shown in Figure 2;

Figure 5 is a volume% vs droplet size graph for two different sized nozzles;

Figure 6 is a volume% vs droplet size graph for two different nozzles sizes used in combination;

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Figure 7 shows schematically a spray bar system for temporary dust suppression applications as also disclosed herein;

Figure 8 shows details of the system as shown in Figure 7;

Figure 9 is a further detail of parts of the system shown in Figure 7; and

Figure 10 is a front view of the system as shown in Figure 7.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a prior art spray block 20 that has been machined from a solid billet. The spray block 20 has a water inlet 22 and three spray exits 24. The block houses three nozzles within the block 20 so as to protect the nozzles from rocks and other debris. The block 20 also has three air inlet holes 26 associated with each nozzle to allow air to flow to nozzle inlet holes.

Figure 2 shows a spray apparatus as disclosed herein. The spray apparatus 30 has an elongate housing 32 that is substantially square in cross section. A water inlet 31 is provided at one end of the housing 32. The housing 32 has a spray surface 34 which includes four water exit holes 36. The apparatus 30 further includes two opposed side walls 38 that each have four air intake slots 40 located equidistant between the water exit holes 36.

The apparatus 30 has mounting brackets 42 for mounting the apparatus 30 to a support. The mounting brackets 42 extend through slots 43 in the housing 32

Figure 3 shows an exploded view of the spray apparatus 30. The housing 32 comprises opposed U shaped bars 44, 46 that each have an upper flange 50, 51 a lower flange 52, 53 and an interconnecting web, 54, 56.

A pipe 60 is located within the housing 32 and extends from one end to the other. The pipe 60 has four nozzle housings 62 mounted thereto. The nozzle housings 62 have air intake apertures 64. The holes for the nozzle housing 62 may be drilled at any spacing and location along the pipe 60. Nozzles 66 are mounted within each nozzle housing 62.

Each web 54, 56 has four sets of three air inlet slots 40. Each web also has two pairs of slots 72 for receiving the ends of the mounting brackets 42. It can be seen that the mounting brackets 42 have a hemispherical recess 74 for receiving the pipe 60.

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It may be seen that each upper flange 50, 52 has opposed hemispherical recesses 76 that when the two parts 44, 46 of the housing are joined, the recesses 76 define the water exit holes 36.

The U shaped bars 44, 46 can be easily machined to provide the air inlets 40 and mounting bracket slots 43 at any required location.

Figure 4 shows a nozzle and nozzle housing arrangement 80 that is suitable for use with the disclosed spray assembly. The nozzle 82 is based on a conventional pressure swirl spray nozzles that have a swirl plate 83 with angled water inlets 84 that introduce water into a swirl chamber 86. The purpose of the swirl plate is to create rotational movement of the liquid that assists with droplet break up and distribution.

The nozzle 82 has an enclosed section 88 surrounding the spray exit 90 from the swirl chamber 86. This section 88 creates a low-pressure zone. Air inlets 94 draw air in from the comparably high pressure air outside the nozzle that creates a swirling motion breaking up the droplets and improving dispersion and velocity.

In a second stage, a nozzle housing 96 is provided that has further inlets 98 that entrain more air into the spray 92, thereby further increasing the above advantageous and desirable effects.

The ability to vary the characteristics of the generated mist/spray by varying the nozzle type and the spacing between nozzles has some important advantages. Different nozzles have droplet size, velocity, and distribution characteristics specific to the individual nozzle. These characteristics are matched to the application generally in terms of dust particle size and velocity, and air velocity in the area they are being used. The ability to utilise various nozzles and different spacings allows the characteristics of different nozzles to be combined in order to better match the properties of the application.

Figures 5 and 6 show the theoretical result of two different nozzles used in combination, the nozzles separately produce relatively narrow size distributions each with a different average size, however, when combined they produce a wide droplet size range which has the potential to capture a greater range of dust particle sizes. This is one reason in which varying nozzle type using this invention will be favourable, another reason is the ability to

2018220007 21 Aug 2018 combine nozzles in a way that will increase the penetration of the sprays droplets. The most effective droplets in a spray are usually the smaller ones, however, these droplets are effected greatly by the air around them and as such slow down and do not travel very far. With this invention, the combination of different nozzles and the distances between them can be arranged in such a way that high velocity large droplet sprays can be used to help carry the smaller more effective droplets further towards the area that is being treated improving the performance of the overall system.

Figure 7 shows a system 100 for temporary dust suppression for use in a dry material container. Figure 7 shows an exemplary part of a side wall 102 and upper shoulder 104 of a ship cargo container. The system 100 has a spray bar 106 having a series of spray nozzles 108 mounted thereto. The spray bar 106 is connected a fluid source (not shown).

The spray bar 106 is mounted to the container by means of two magnets 109. Each magnetic 109 is switchable between a magnetic state and a nonmagnetic state that allows the magnets for magnetically engage the ferromagnetic shoulder 104 of the container wall. Two cables 110 extend between the magnets 109 and the spray bar 106.

Figures 8a and 8b show details A and B of Figure 8. Figure 8A shoes a detail of the magnet 109 and switch 120. Figure 8 B shows that each cable 110 is fixed to the spray bar 106 by means of a mount 112. The mount 112 has a pipe bracket part 114 and a foot part 116. The pipe bracket 114 engages the spray bar 106 and mounting screws 115 on the pipe bracket 114 can be loosed or removed between an engagement position and a free position such that the mount 112 can fix the spray bar at any selected position along the length thereof (see in Figure 10). This can assist with flexibility of system design.

The bracket 112 can also be loosened to allow for the spray bar 106 to rotatably move relative to the bracket 112 and side wall 102. This allows for the angle of spray direction from the spray nozzles 108 to be varied, as shown in Figure 9. The foot part 116 is trapezoidal such that the base 118 is flat and sits flush against the container wall 102.

Figure 9 also shows that the height H of the spray bar 106 relative to a container floor can be easily varied by moving the magnets 109 towards and away from the container edge 120. The cable length can also be readily varied.

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Figure 10 shows that the distance D between magnets can be readily adjusted so as to tailor the system to different applications, cargo hold sizes and the like.

It will be appreciated that the system as disclosed herein allows for quick and efficient mounting of a spray apparatus to a support. The use of this system allows for very quick mounting to any ferromagnetic surface without the need for any special fixtures to already be in place. This may reduce cost and time associated with the setup of a temporary dust suppression system.

The flexibility of the design is a desirable feature for setting up temporary dust suppression systems. The magnets in combination with the cable system not only allow for quick mounting but also give flexibility in mounting position. The magnets can be positioned where convenient with no constraint on the distance between them the distance to the spray bar (length of cable can be adjusted). The mounting foot and cable system also allows significant adjustability of the setup, the mounting foot allows for the angle of the spray outlet to be adjusted to suit the specific application and the cables allow for the position of the spray bar to be adjusted up and down to suit the position of the dust source. This allows the user to quickly and easily “tune” the dust suppression system to gain the highest dust capture efficiency possible. Such tuning is not usually possible in any dust suppression system let alone one that can be setup for temporary use in under an hour.

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

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Claims (14)

1. A spray apparatus for dust suppression, the spray apparatus comprising;

an elongate housing having a first side wall, a second side wall and a spray wall having at least one spray exit hole therein, an elongate fluid conduit within the housing; and at least one spray nozzle fluidly mounted to the elongate fluid conduit at a position such that a fluid sprayed from the spray nozzle will exit the housing through a spray exit hole.

2. The spray apparatus of claim 1, wherein the housing is modular in construction to allow for ease of manufacture.

3. The spray apparatus of claim 2, wherein the housing has a first elongate member and a second elongate member that can be engaged to define the housing.

4. The spray apparatus of claim 3, wherein the first and second elongate members are U shaped metal bars having opposed flanges connected by a web.

5. The spray apparatus of claim 4, wherein the respective webs form the first and second side walls of the housing when they are engaged and the spray wall is defined by the abutting flanges of the respective elongate members.

6. The spray apparatus of claim 5, wherein the abutting flanges have a profile having spaced and opposite hemispherical recesses that when the flanges abut, define the spray exit holes.

7. The spray apparatus of any one of claims 1 to 6, wherein the spray nozzles are of the type having an air inlet for allowing air to become entrained with the sprayed fluid and the housing further comprises at least one air inlet for allowing air into the housing.

8. The spray apparatus of any one of claims 1 to 7, comprising at least one spray nozzle that produces a spray having first droplet particle size distribution over a first spray area and a second nozzle that produces a spray having a second droplet particle size distribution and the spacing between the at least first nozzle and the at least second nozzle is predetermined such that there is at least some overlap of the first spray area and the second spray area.

9. A method of supressing dust at a location, comprising;

2018220007 21 Aug 2018 assessing dust level values and particle size values at the location;

calculating from the assessed values, a desired droplet particle size distribution, volume and particle velocity; and selecting spray nozzles to provide the desired spray droplet particle size distribution and manufacturing a spray apparatus as disclosed herein with the selected spray nozzles and mounting the spray apparatus at the location.

10. A dust suppression system for use in a container having a ferromagnetic surface part for a dry bulk material comprising;

at least one elongate fluid conduit having a plurality of fluid spray nozzles fluidly mounted thereto;

a fluid supply fluidly connectable to the at least one elongate fluid conduit;

at least one magnet that is switchable between a magnetic state and a nonmagnetic state and in use can magnetically engage and disengage a ferromagnetic surface part of the container; and a connector for connecting the elongate fluid conduit to a magnet.

11. The system of claim 10, wherein the connector is flexible such as a cable.

12. The system of claim 10 or claim 11 comprising a mount for connecting the connector to the elongate fluid conduit that allows for removable connection such that the mounting position on the spray bar can be changed as desired.

13. The system of claim 12, wherein the mount further allows for rotation of the elongate fluid conduit relative to the mount to allow for spray angle of the spray nozzles to be varied.

14. A spray apparatus for use in a container having a ferromagnetic surface part for a dry bulk material comprising;

at least one elongate fluid conduit having a plurality of fluid spray nozzles fluidly mounted thereto;

a fluid supply fluidly connectable to the at least one elongate fluid conduit;

at least one magnet that is switchable between a magnetic state and a nonmagnetic state and in use can magnetically engage and disengage a ferromagnetic surface part of the container; and a connector for connecting the elongate fluid conduit to a magnet.

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Figure 4

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Figure 6

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Figure 8a