TECHNICAL FIELD

[0001] The present invention generally relates to a device for separating a stream of compressed gas into separate hot and cold streams.

BACKGROUND

[0002] Cooling devices, commonly known as vortex tubes, are known devices that separate a supply of compressed gas, typically air, into a cold stream and a hot stream without the use of any moving parts. Despite the concept being developed some time ago, the devices have found only limited use.

[0003] Applications of such devices are generally restricted to applications where a source of compressed air is readily available and where a localised cooling effect is required. For example, the devices are sometimes used for cooling cutting tools or for quickly freezing scientific samples in a laboratory. They are not considered practical for large scale cooling, however, due to their poor efficiency and size limitations.

[0004] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

SUMMARY

[0005] According to one example aspect, there is provided a device, including an inlet, a cold air outlet and a hot air outlet, wherein the device is configured to accept a supply of compressed gas at the inlet and to produce a cold gas stream that exits from the cold air outlet and a hot gas stream that exits from the hot air outlet.

[0006] In one form, the device further includes a ventilated heat shield. Preferably, the device uses a venturi effect to draw ambient air through the heat shield. In an alternative form, the device includes an orifice to provide air from the inlet to inside the heat shield. In another form, the device includes an adjustable gas accelerator.

[0007] According to another aspect, there is provided a device, comprising: a tube with a hot gas outlet at a first end and a cold gas outlet at a second end; an inlet in fluid communication with the tube; and an accelerator associated with the tube, wherein the device is configured to accept a supply of compressed gas at the inlet, the accelerator causing the air to form a vortex inside the tube and the device producing a cold gas stream that exits from the cold gas outlet and a hot gas stream that exits from the hot gas outlet.

[0008] In one form, the device further includes a ventilated heat shield surrounding at least a portion of the tube. In other particular, but non-limiting, example forms: air flowing within the heat shield is in contact with the outside of the tube; and the heat shield extends past the first end of the tube.

[0009] In one example form, the device includes an orifice to supply air from the inlet to a space between the tube and the heat shield. In another example form, the hot gas stream exiting the hot gas outlet draws ambient air through the heat shield.

[0010] In one form, the heat shield is connected to the tube by flanges that enable heat to be conducted away from the tube. Preferably, air or gas flowing within the heat shield and outside the tube is in contact with the flanges.

[0011] In another form, the accelerator includes a helical groove. Preferably, the helical groove of the accelerator causes the gas entering the tube via the inlet to be channelled in a vortex motion towards the hot gas outlet. In one particular example form, the accelerator includes a substantially cylindrical portion with an outer surface in which the helical groove is formed.

[0012] In yet another form, the accelerator includes vanes that cause the vortex motion to be imparted on the gas as it moves from an outer perimeter towards the centre of the tube. In one particular example form, the accelerator includes one or more slots adjacent to the vanes. [0013] In yet another form, a flow rate of gas through the accelerator is adjustable. In one particular example form, the flow rate of gas through the accelerator is adjusted by moving a delivery controller in a longitudinal direction within the tube at least partially within a space central to the vanes.

[0014] In still further particular, but non-limiting, example forms: a diameter of the tube at the second end is greater than a diameter of the tube proximal to the accelerator; the device further includes a muffler surrounding at least a portion of the tube; and/or the muffler surrounds a portion of the tube proximal to the first end.

[0015] In still further particular, but non-limiting, example forms: the device further includes a bracket fixed to the tube that allows the device to be attached to a fixed object; and/or the device is suitable for use in an underground mine.

BRIEF DESCRIPTION OF FIGURES

[0016] Example embodiments should become apparent from the following description, which is given by way of example only, of at least one preferred but non- limiting embodiment, described in connection with the accompanying figures, wherein:

[0017] Figure 1 illustrates an isometric view of an embodiment of a device according to the present invention;

[0018] Figure 2 illustrates a bottom view of the device of Figure 1;

[0019] Figure 3 illustrates a front view of the device of Figure 1;

[0020] Figure 4 illustrates an end view of the device of Figure 1;

[0021] Figure 5 illustrates a front cross sectional view of the device of Figure 1, the cross section being taken through the section as illustrated by arrows 200 in Figure 2;

[0022] Figure 6 illustrates in greater detail the area circled in Figure 5;

[0023] Figure 7 illustrates an exploded isometric view of the components making up a central portion of the device of Figure 1 ; [0024] Figure 8 illustrates an exploded isometric view of the device of Figure 1;

[0025] Figure 9 illustrates a front cross sectional view of the device of Figure 1, the cross section being taken through the section as illustrated by arrows 200 in Figure 2;

[0026] Figure 10 illustrates in greater detail the area circled in Figure 9;

[0027] Figure 11 illustrates a bottom view of a spin chamber from the device of Figure l ;

[0028] Figure 12 illustrates an isometric view of the spin chamber of Figure 11;

[0029] Figure 13 illustrates an isometric cross sectional view of the spin chamber of Figure 11;

[0030] Figure 14 illustrates a front cross sectional view of the spin chamber taken through the section as illustrated by arrows 201 of Figure 11;

[0031] Figure 15 illustrates an end view of the spin chamber of Figure 11;

[0032] Figure 16 illustrates a front view of an accelerator from the device of Figure 1;

[0033] Figure 17 illustrates an isometric view of the accelerator of Figure 16;

[0034] Figure 18 illustrates a reverse isometric view of the accelerator of Figure 16;

[0035] Figure 19 illustrates a front view of the accelerator from Figure 16;

[0036] Figure 20 illustrates an end view of the accelerator from Figure 16;

[0037] Figure 21 illustrates a top view of a delivery controller from the device of Figure 1;

[0038] Figure 22 illustrates an isometric view of the delivery controller of Figure 21;

[0039] Figure 23 illustrates a front view of the delivery controller of Figure 21;

[0040] Figure 24 illustrates an end view of the delivery controller of Figure 21; [0041] Figure 25 illustrates a front view of a heat shield from the device of Figure 1;

[0042] Figure 26 illustrates an end view of the heat shield of Figure 25;

[0043] Figures 27A to 27D illustrate bottom, rear, isometric and end views respectively of a heat shield from an embodiment of the device where the heat shield is ventilated from orifices in the spin chamber;

[0044] Figure 28 illustrates an exploded isometric view of an embodiment of the device that includes a variable vane accelerator;

[0045] Figure 29 illustrates a front cross sectional view of the device of Figure 28 in a fully open configuration;

[0046] Figure 30 illustrates a front cross sectional view of the device of Figure 28 in a fully closed configuration;

[0047] Figure 31 illustrates in greater detail the area circled in Figure 30;

[0048] Figure 32 illustrates in greater detail the area circled in Figure 29;

[0049] Figure 33 illustrates an isometric cross sectional view of the device of Figure 28 in a fully closed configuration;

[0050] Figure 34 illustrates an isometric cross sectional view of the device of Figure 28 in a fully open configuration;

[0051] Figure 35 illustrates a front view of a variable accelerator from the device of Figure 28;

[0052] Figure 36 illustrates an isometric view of the accelerator of Figure 35; [0053] Figure 37 illustrates a reverse isometric view of the accelerator of Figure 35; [0054] Figure 38 illustrates a front view of the accelerator from Figure 35; [0055] Figure 39 illustrates an end view of the accelerator from Figure 35; [0056] Figure 40 illustrates a bottom view of a spin chamber from the device of Figure 28;

[0057] Figure 41 illustrates an isometric view of the spin chamber of Figure 40;

[0058] Figure 42 illustrates an isometric cross sectional view of the spin chamber of Figure 40 taken through section 202;

[0059] Figure 43 illustrates a front cross sectional view of the spin chamber of Figure 40 taken through section 202;

[0060] Figure 44 illustrates an end view of the spin chamber of Figure 40;

[0061] Figure 45 illustrates a front view of a variable delivery controller from the device of Figure 28;

[0062] Figure 46 illustrates an isometric view of the delivery controller of Figure 45;

[0063] Figure 47 illustrates a reverse isometric view of the delivery controller of Figure 45;

[0064] Figure 48 illustrates a front view of the delivery controller of Figure 45;

[0065] Figure 49 illustrates an end view of the delivery controller of Figure 45;

[0066] Figure 50 illustrates a bottom view of a spin chamber with ventilation orifices;

[0067] Figure 51 illustrates a left end view of the spin chamber of Figure 50;

[0068] Figure 52 illustrates a front view of the spin chamber of Figure 50;

[0069] Figure 53 illustrates a right end view of the spin chamber of Figure 50;

[0070] Figure 54 illustrates a front cross sectional view taken through section 203 of the spin chamber of Figure 51 ;

[0071] Figure 55 illustrates a left isometric view of the spin chamber of Figure 50; [0072] Figure 56 illustrates a right isometric view of the spin chamber of Figure 50;

[0073] Figure 57 illustrates a bottom view of a single helix vane accelerator;

[0074] Figure 58 illustrates a left end view of the helix vane accelerator of Figure 57;

[0075] Figure 59 illustrates a front view of the helix vane accelerator of Figure 57;

[0076] Figure 60 illustrates a right end view of the helix vane accelerator of Figure 57;

[0077] Figure 61 illustrates a left isometric view of the helix vane accelerator of Figure 57;

[0078] Figure 62 illustrates a right isometric view of the helix vane accelerator of Figure 57;

[0079] Figure 63 illustrates a bottom view of a double helix vane accelerator;

[0080] Figure 64 illustrates a left end view of the helix vane accelerator of Figure 63;

[0081] Figure 65 illustrates a front view of the helix vane accelerator of Figure 63;

[0082] Figure 66 illustrates a right end view of the helix vane accelerator of Figure 63;

[0083] Figure 67 illustrates a left isometric view of the helix vane accelerator of Figure 63;

[0084] Figure 68 illustrates a right isometric view of the helix vane accelerator of Figure 63

[0085] Figure 69 illustrates a bottom view of an assembly that includes an inlet tube, a double helix vane accelerator and a spin chamber with ventilation orifices;

[0086] Figure 70 illustrates a front view of the assembly of Figure 69;

[0087] Figure 71 illustrates an end view of the assembly of Figure 69; [0088] Figure 72 illustrates a front cross sectional view taken through section 204 of the assembly of Figure 69, with the inlet tube shown in full;

[0089] Figure 73 illustrates an isometric view of the assembly of Figure 69;

[0090] Figure 74 illustrates an isometric cross sectional view taken through section 204 of the assembly of Figure 69, with the inlet tube shown in full;

[0091] Figure 75 illustrates an exploded isometric view of the assembly of Figure 69;

[0092] Figure 76 illustrates a left end view of a spin chamber that includes heat shield ventilation orifices;

[0093] Figure 77 illustrates a bottom view of the spin chamber from Figure 76;

[0094] Figure 78 illustrates an isometric view of the spin chamber from Figure 76;

[0095] Figure 79 illustrates an isometric cross sectional view of the spin chamber taken through section 205 of Figure 77;

[0096] Figure 80 illustrates a rear cross sectional view of the spin chamber taken through section 205 of Figure 77;

[0097] Figure 81 illustrates a right end view of the spin chamber from Figure 76;

[0098] Figure 82 illustrates a bottom view of an embodiment of an accelerator that includes fins;

[0099] Figure 83 illustrates a left isometric view of the accelerator from Figure 82;

[0100] Figure 84 illustrates a right isometric view of the accelerator from Figure 82;

[0101] Figure 85 illustrates a front view of the accelerator from Figure 82;

[0102] Figure 86 illustrates a right end view of the accelerator from Figure 82; [0103] Figure 87 illustrates an isometric view of another embodiment of a device according to the present invention;

[0104] Figure 88 illustrates a top view of the device from Figure 87;

[0105] Figure 89 illustrates a front view of the device from Figure 87;

[0106] Figure 90 illustrates an end view of the device from Figure 87;

[0107] Figure 91 illustrates a front cross sectional view of the device from Figure 87;

[0108] Figure 92 illustrates an enlarged front cross sectional view of the circled area from Figure 91;

[0109] Figure 93 illustrates an exploded isometric view of the device from Figure 87;

[0110] Figures 94A and 94B illustrate end and front cross sectional views respectively of an alternative embodiment of orifice plate; and

[0111] Figures 95A to 95E illustrate left end, front, right end, direction 206 (see Figure 95C) and isometric views respectively of a heat shield end cap.

DETAILED DESCRIPTION

[0112] The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

[0113] In the Figures, incorporated to illustrate features of an example embodiment, like reference numerals are used to identify like parts throughout the Figures.

[0114] Referring to Figure 1, together with Figures 2 to 7, a preferred embodiment of a device 10 according to the present invention is shown. The device 10 can be connected to a source of compressed gas, typically air, at an inlet 11 of an inlet assembly 12. This compressed gas is separated by the device 10 into a cold stream that exits from a cold end assembly 13 at a cold gas outlet 14 and a hot stream that exits from a hot end assembly 15 at a hot gas outlet 16.

[0115] A bracket 18 allows the device 10 to be fixed in place during use, by attaching the device to a fixed object. For example, the bracket 18 may allow the device 10 to be suspended from a roof.

[0116] Referring to Figure 8, the hot end of the device 10 includes a heat shield 20 that is fitted over the inner tube 22. Flanges 24 connect the inner tube 22 to the heat shield 20. A discharge orifice plate 26 is fitted to the end of the inner tube 22, however this outlet is located some distance from the hot gas outlet 16, as shown in Figure 9. A wire 28 extends across the hot gas outlet 16.

[0117] The cold end 13 of the device 10 includes an outer cover 30 and an inner tube 32 being connected to one another by foam rings 34. The cold gas outlet 14 includes a socket 36 connected to an orifice plate 38.

[0118] The high volume of air exiting the relatively narrow tube at the cold end of a vortex tube traditionally resulted in vortex tubes being very loud, with resulting safety implications. The design of the cold end assembly 13 of the present invention, however, reduces the noise produced. The outer cover 30 and foam rings 34 serve as a muffler on the cold end inner tube 32.

[0119] The foam rings 34 are made from Fire Resistant Anti Static (FRAS) material in the present embodiment, but it will be appreciated that they may be made from other materials in alternative embodiments. The present invention also uses mesh to form the cold end inner tube 32, however this may not be the case in alternative embodiments. This design of the cold end assembly 13 allows the noise to be reduced to an acceptable level.

[0120] The central part of the device 10 includes a spin chamber 40, a vane accelerator 42 having vanes 43, and a delivery controller 44. Referring to Figures 11 to 15, the spin chamber 40 is shown in more detail. In use, compressed gas enters the spin chamber 40 via a valve 46 and a tube 48 that connect to the opening at the top of the spin chamber 40. Apart from this opening, the main body of the spin chamber forms a hollow cylinder that is open at the ends. The inside of the spin chamber is smooth apart from a lip 41 at one end.

[0121] Referring to Figures 16 to 20, the vane accelerator 42 is shown in more detail. This device is also substantially cylindrical and has a hollow interior, so that when the device 10 is assembled it forms part of a tube extending from the orifice plate 26 to the cold gas outlet 14. Figure 9 illustrates that the various components of the device together form a continuous tube that extends from the cold gas outlet 14 through to the orifice plate 26 and ultimately the hot gas outlet 16.

[0122] The accelerator 42 is sized to fit snugly inside the spin chamber 40, either abutting or very close to the inside surface (see Figure 10). Vanes 43 protrude from one end of the accelerator 42 and a lip extends outwardly from the other end, thereby limiting how far into the spin chamber 40 the accelerator 42 can be placed. The outer ends of the vanes 43 are smaller in diameter than the main body of the accelerator 42. The vanes 43 are tapered to a point toward the central axis of the accelerator 42 and are also have curved edges, thereby creating curved channels between the vanes.

[0123] Referring to Figures 21 to 24, the delivery controller 44 is shown in more detail. The delivery controller 44 has a hollow interior 54 which is tapered or stepped so that an opening at one end is larger than an opening at the other end. The portion of the delivery controller 44 with the largest diameter has a similar outer diameter to the outer edges of the vanes 43 of the accelerator 42.

[0124] Figure 10 shows the detail of the spin chamber 40, accelerator 42 and delivery controller 43 when assembled. It can be seen in this Figure that when assembled there is a space 52 created between the inside of the spin chamber 42 and the outside of the delivery controller 43 and the outside of the vanes 43 and associated smaller diameter section of the accelerator 42.

[0125] This space 52 allows gas entering the spin chamber 40 via the tube 48 to flow around the entire circumference of the delivery controller 43 and the accelerator 40. This, in turn, allows the gas to flow from this outer perimeter, between all of the vanes 43 towards the cavity 54, as will be described in more detail below.

[0126] The general function of the device 10 will now be described. Compressed air, typically at a pressure in the range of 500 to 800kPa, enters the spin chamber 40 via the compressed air inlet assembly 12. The vane accelerator 42 forces the inlet air into a specific cyclonic motion known as a vortex in the spin chamber 40. From here the air is propelled laterally into the hot air end assembly 15, rotating down the inner tube 22 to the discharge orifice plate 26 at an estimated l,000,000rpm.

[0127] From this step in the process, the below events typically take place in a constant state whilst the compressed air is applied to the inlet assembly 12 of the device 10. Firstly, a controlled amount of hot air is discharged from the orifice plate 26. The remaining rotating air that is not discharged from the orifice plate 26 flows back down through the vortex inner low pressure area, as a secondary inner vortex, rotating in the same direction and with the same angular velocity as the outer vortex in the hot end assembly 15.

[0128] Dynamic energy is given up as heat from the inner low pressure vortex to the outer low pressure vortex, due to the inner vortex having a loss in angular momentum. Otherwise stated, the inner vortex spins at the same rotational speed as the outer vortex rather than an expected increase in speed of the inner vortex as dictated by the principle of conservation of angular momentum. This shift in angular momentum creates a "drag" on the inner vortex, slowing it and creating heat energy that it gives off to the outer vortex, effectively cooling the inner vortex.

[0129] The heat given up by the inner vortex is transferred through the material consisting of the hot end assembly 15. The removal of the dissipating heat from the hot end assembly 15 is enhanced by the addition of the venturi and heat sink effect, provided by the heat sink transfer strips 24 and the ventilated heat shield 20. The addition of the strips 24 and heat shield 20 allow for a more efficient removal of generated heat and greater rate of heat transfer interaction, between the inner and outer vortex operating within the hot end assembly 15. This is believed to contribute to the improved efficiency of the present invention over known vortex tubes.

[0130] The cooled inner vortex air stream passes back through the spin chamber 40 into and through a tapered re-entrant cavity 54, and passes through the centre of the vane accelerator 42, tangentially to the vanes in which the supply of compressed air entered the device. On exit from the tapered re-entrant cavity 54 and vane accelerator 42, the air begins its expansion and further cools as it exits the device 10 via the noise suppressor assembly or cool end assembly 13.

[0131] The air discharged from the orifice plate 26 creates a venturi effect that draws air through the heat shield 20. This air mixes with the air from the orifice plate 26 prior to exiting through the outlet 16.

[0132] The addition of the ventilated heat shroud 20 to a vortex tube has assisted in producing a device that allows adequate control of the risks associated with excessive surface temperatures in hazardous areas, operate at safe and manageable noise pressure levels, negate localised safety injuries from burns and increase the efficiency of the device's output cold temperature, without changing the volume and rate of air projected from the cold end assembly 13 of the device 10.

[0133] Typically, to achieve a colder temperature at the cold end discharge on a traditional vortex tube, it would be necessary to either increase the volume of hot air released from the discharge orifice plate, thus reducing the velocity and volume of cooled air from the cold end, or, change the dynamics of the vane accelerator tapered re-entrant cavity, known as a generator in the traditional vortex tube, to one which in turn would dramatically reduce the volume and velocity of cooled air from the cold end, by the nature of its design requirements.

[0134] To achieve the cold air discharge temperature, velocity and volume required at the cold gas outlet 14, the ventilated heat shield 20 was developed to cool the hot end inner tube 22, in which the vortex action and inner gas heat exchange takes place. The ventilated heat shield 20 is attached, separated and bonded to the hot end inner tube 22 by heat sink transfer strips 24.

[0135] The ventilated heat shield 20 is flared at its intake end 60 (see Figure 10, for example), with the intake end 60 set according to the required gap to allow the most efficient volume of venturi effect air to be drawn through the inner space between the hot end inner tube 22 and the ventilated heat shield 20. Slots 62 are provided to accommodate the bracket 18 (see for example Figures 25 and 26).

[0136] The venturi effect of the ventilated heat shield 20 is achieved by means of extending it a nominal distance past the hot air discharge orifice plate 26 that is attached to the hot end inner tube 22. As the air discharges from the orifice plate 26, it creates a draw of ambient air through the flared end 60 of the ventilated heat shield 20, down across and in contact with the heat sink transfer strips 24 and the hot end inner tube 22. This has the effect of cooling the hot end inner tube 22, where heat is being generated through the heat exchange occurring in the high and low pressure gas vortex in the hot end inner tube 22.

[0137] By removing the heat generated in the hot end inner tube 22 by means other than natural dissipation, some or all of the following benefits and measurable observations may be achieved: reduced hot end air discharge temperatures; reduced hot air end pipe surface temperatures; reduced sound pressure level from hot air end discharge; reduced cold end air temperatures; heat shield serves as correct size to fit standard 2" flexible hose to duct away the warm venturi discharge air, from the immediate area being cooled, without creating back pressure on the device creating inefficiencies, or contact with the hotter inner hot end air pipe; removal of the potential of harm to persons from heat related burns due to the manual handling of the device; and increased device efficiency with relation to the cold end air discharge temperature, velocity and volume.

[0138] In an alternative embodiment of the invention, the ventilated heat shield is closed to the atmosphere on the intake side. Instead of drawing air using a venturi effect, it is supplied with compressed air via one or more orifices in the tube 48 or the spin chamber 40. In such an embodiment, the ventilated heat shield 20 attaches to and substantially seals with the spin chamber 40 in a similar manner to how the outer cover 30 of the noise suppressor attaches to the vane accelerator 42.

[0139] This alternative method of ventilating the hot end of the device ensures there is no build up of dust and foreign materials in the inner heat tube 22 if it is operating in extremely dusty, wet and/or humid conditions.

[0140] Referring to Figures 76 to 81, such an embodiment of a spin chamber 40 is shown that includes a number of orifices 102 extending from an inlet 104 at the hollow interior 105 of the spin chamber 40 to an outlet 106. The heat shield seals with the end of the spin chamber 40, rather than being open to the atmosphere as described previously. Figures 27 A to 27C show such a heat shield, for example, while Figures 91 and 92 show a complete assembly.

[0141] Therefore, the outlets 106 of the orifices 102 are located in the space between the outside of the inner tube 22 and the inside of the heat shield. During operation, air enters the hollow interior 105 via the inlet 107, as in previous examples, where a vortex is generated. In the present embodiment, however, a small portion of the air in the hollow interior 105 is bled off, flowing through the orifices 102 and thereby ventilating the space inside the heat shield.

[0142] The embodiment shown in the Figures includes three ventilation orifices 102, however it will be appreciated that the number of orifices 102 or the diameter of the orifices 102 can be varied as necessary to adjust the flow rate and therefore the level of ventilation to the heat shield. For example, a single orifice 102 may be used in some embodiments, while in others there may be two, four, or more than four. A higher flow rate will provide increased ventilation, but may result in degraded performance of the spin chamber 100.

[0143] Using three orifices 102 in the present embodiment is advantageous, as there are three flanges 24 connecting the heat shield to the inner tube 22, and therefore three separate passages through the inside of the heat shield. Of course, other embodiments may change both the number of passages and the number of orifices so that there are equal numbers of each or so that they are in a particular ratio to one another.

[0144] Referring to Figures 50 to 56, yet another embodiment of a spin chamber 100 is shown that also includes a number of orifices 102 extending from an inlet 104 at the hollow interior 105 of the spin chamber 100 to an outlet 106. The inner tube 22 fits to a narrow end portion 108 and a heat shield seals with a portion of the main body 109 of the spin chamber 100, rather than being open to the atmosphere as described previously. This embodiment requires much longer orifices 102 due to the long accelerator it is designed to be used with, as will be described in more detail below.

[0145] It will be appreciated that different operating conditions and/or applications may require optimisation of the size and/or number of orifices 102 to achieve optimal overall performance of the device, as the performance of the spin chamber is traded off against the level of ventilation in the heat shield, each of which impact this overall performance.

[0146] Referring to Figures 82 to 86, an alternative form of accelerator 42 is shown. Similar to the previous embodiment, this accelerator 42 still includes an outer surface 110 sized to fit snugly inside the spin chamber 40, a lip 111 at one end to abut the end of the spin chamber 40 and position the accelerator 42 appropriately, and a narrow section 112 that includes the vanes 43. The embodiment additionally includes a number of fins 115 that form part of the main body section, effectively being formed by creating slots into the cylindrical surface 110.

[0147] The fins 115 alter the heat conduction and dissipation properties of the accelerator 42 and may thereby improve the overall performance of the device 10. In one prototype tested, these fins 115 reduced the temperature of the gas exiting the cold gas outlet 14 by 2-3°C.

[0148] While the fins 115 may not be actively cooled, they reduce the thermal mass of the accelerator 42 and can reduce the heat conducted along the length of the accelerator 42, thereby preventing conduction of heat from the warm end assembly 15 to the cold end assembly 13. The fins 115 thereby prevent the cold end inner tube 32 becoming warm and reheating the cooled gas before it can exit the device 10.

[0149] In prior art vortex tubes, the generator, which is a component similar to the vane accelerator 46 of the present invention, are an individual component that can be removed and changed to suit various requirements of temperature, volume and velocity required of the discharged cold end air from the device. The present invention may use a similar system, as described in relation to the preferred embodiment above, or may alternatively use a device that allows variation without changing the vane accelerator 46. An alternative embodiment that allows adjustment of the vane accelerator will now be described.

[0150] The design of the fixed and variable vane accelerators are such to deliver a fixed volume of air to the device to match the device specifications and requirements of output delivery. The fixed and variable vane accelerator is a merged component, incorporating the vane accelerator as part of the spin chamber body ends.

[0151] The inclusion of this merger of components may allow for the following benefits and measurable observations: greater cost control of manufacture of components; reduced resonance and thermal loss in the transfer of cooled air through the tapered reentrant cavity to the noise suppressor assembly; component less susceptible to wear through normal use; and increased spin body strength.

[0152] The fixed vane accelerator component 42 has the respective vanes 43 machined in a manner that differs from the normal practice, whereby the vanes do not allow the inlet compressed air flow to intersect or collide directly with an air input from a vane located adjacent at 90°. Traditional vortex tube generators see every second vane at 90° to each other. This results in the air exiting any particular vane colliding with the next adjacent vane's airflow and wall structure in which the vane is machined.

[0153] The cool tube fixed vane accelerator 42 has its vanes 43 machined in a configuration as such the cyclonic vortex motion is assisted by attempting to add each vane's air supply to the spin chamber 40 in a progression that already sees the air stream curved, with minimal collision with adjacent vane airstreams or vane wall structures.

[0154] The design of the vane accelerator input vanes 43 may allow for the following benefits and measurable observations: increased air input efficiency; reduced air input stream collision; input air stream cyclonic vortex action assistance within the spin chamber; and reduced component wear from normal frictional inefficiencies.

[0155] The design of the cool tube variable vane accelerators are such that they can either be a single input fixed vane component or a variable input vane component.

[0156] Referring to Figures 28 to 49, an embodiment of the invention is shown that includes an adjustable or variable vane accelerator 82 and a variable output delivery controller 84. The variable vane accelerator 82 is part of a system as opposed to the fixed vane accelerator 42 that is a standalone merged component.

[0157] A modified spin chamber 80 is also used, which includes an internal thread 85 that couples with an external thread 86 of the delivery controller 84. The spin chamber also includes an internal flange 88 that partially separates the threaded portion of the spin chamber from the remainder of the spin chamber 80. A clockwise or anticlockwise rotation of the delivery controller 84 causes it to move in an axial or longitudinal direction within the spin chamber 80.

[0158] The variable vane accelerator 82 has an extended depth of the input vanes 83 such that the input air volume can be adjusted. An offset in the variable vane accelerator 82 allows for the delivery controller 84 to screw down clockwise such that an end portion 89 moves into the central offset of the accelerator 82. This in turn reduces the available delivery passage volume between the air vanes 83, thereby reducing the amount of cyclonic air being provided to the hot end inner tube 22.

[0159] An anticlockwise rotation of the variable output delivery controller 84 will conversely see an increase in the available air vane delivery passage volume of cyclonic air to the hot end inner tube 22. The flange 88, however, ensures that the accelerator vanes 83 remain encased on either side by a wall, to ensure efficient operation of the vanes 83. [0160] The design of the variable vane accelerator input vanes may allow for the following benefits and measurable observations: increased air input efficiency; reduced air input stream collision; input air stream cyclonic vortex action assistance within the spin chamber; reduced component wear from normal frictional inefficiencies; variable volume input air into the spin chamber; variable temperature, volume and velocity of output air streams on both the hot and cold ends with the use of a solitary component; and greater manufacturing cost control with a singular item used for multiple temperature, volume and velocity variations.

[0161] The device 10 may be used in a wide variety of applications, such as but not limited to a workplace environment cooling situation to combat such things as heat stress, and equipment or infrastructure overheating.

[0162] The bracket 18 allows the device to be easily secured in a desired location. Referring to Figure 8, the bracket 18 includes two flanges 70 with a bolt 72, nut 73 and washers 74 being used to pivotally secure a connector 76. The connector can be fixed from pivoting by a rod 77. A first nut 78 and a second nut 79 can be used to fix the connector to some other external fixture, such as a roof, wall or piece of machinery. In one example, the connector 76 may be coupled to a magnetic device that is in turn attached to a fixture.

[0163] Referring to Figures 57 to 62, another alternative form of vane accelerator 120 is shown. The single helix vane accelerator 120 includes a body 122, a reduced diameter central section 123 and a vane portion 124. The central section 123 includes ridges 125, while the vane portion 124 has a substantially cylindrical outer surface 126 in which a helical groove 128 is formed. The ridges 125 can help to ensure that any heat being conducted along the length of the accelerator 120 towards the cold end assembly 13 is transferred to the gas entering via the inlet 12, rather than being conducted to the body 122 and possibly all the way to the cold end inner tube 32.

[0164] Referring to Figures 63 to 68, a double helix vane accelerator 120 is shown, which is largely the same as the single helix vane accelerator 120 with the addition of a second helical groove 129 formed in the outer surface 126 of the vane portion 124. [0165] It will be appreciated that the helix vane accelerator 120 could also be formed with more than two helical grooves 128. For simplicity, the reference numeral 128 as used in the following description may refer to either of the helical grooves 128, 129.

[0166] Referring now to Figures 69 to 75, the spin chamber 100 with ventilation orifices 102 is shown together with a helical vane accelerator 120. It will be appreciated that the helical vane accelerator 120 can also be used with a spin chamber 40 that does not include ventilation orifices 102. These Figures also show an inlet tube 132 fitted to the inlet 107 of the spin chamber 100.

[0167] The operation of this embodiment is similar to that as described previously. Compressed air enters the spin chamber 100 through the inlet tube 132. There is some space in the hollow interior 105 at this location due to the central section 123 of the helix vane accelerator 120. The air then flows along the helical vanes 128, which due to their shape create a vortex in a similar way to the vanes 42 of the previous embodiments. The air then travels along the hot end assembly 15, with the cooled inner vortex returning and passing through the centre 135 of the helix vane accelerator 120 and into the cold end assembly 13.

[0168] The helical vanes 128 may be advantageous as they impart lateral momentum to the air along the length of the tube, in addition to creating the angular momentum about the central axis. This may improve the operation of the device by assisting the flow of the outer vortex along the length of the tube, rather than only directing the air to create the vortex without imparting any lateral momentum, as was the case in the previous embodiments.

[0169] Use of the helical vane 128 can allow the hot end orifice 26 to be reduced in size, as it is not necessary to release as much air at the hot end to train the gas towards the hot end due to the lateral momentum imparted to the outer vortex by the helical vane 128. Reducing the size of the orifice at the hot end and thereby reducing the rate of air discharged from the hot end can lead to increases in efficiency of the device. [0170] In the embodiment shown, the helical vanes 128 are angled at 60° to the axis of the helix vane accelerator 120. It will be appreciated that other angles may be used depending on the specific design of the helix vane accelerator 120, spin chamber 100 and other components. For example, the helical vanes 128 may be angled at between 58° and 62°, between 55° and 65°, or at other angles outside this range.

[0171] The use of the helical vanes 128 can lead to advantageous effects on the device, including: reduced cold end temperatures at similar flow rates to traditional vortex accelerators: reduction in inlet gases creeping back down towards the cold outlet prior to travelling down the hot tube (an ambient air temperature "warm ring" has been recorded surrounding the cold air stream at the cold outlet on prior art devices); and simplified manufacture with fewer parts and a screw together assembly as opposed to welded in some other embodiments and prior art devices.

[0172] Referring to Figures 88 to 93, a complete device 10 is shown that includes the ventilated heat shield from Figures 27A to 27D and the accelerator from Figures 82 to 86. This heat shield 20, rather than being configured to have a hose attached or simple opening as described previously, includes a series of slots 140 positioned beyond the end of the inner tube 22.

[0173] An end cap 142 is removably fitted to the end of the heat shield 20 and is attached to the heat shield 20 using a tether 144 that extends from an eyelet 145 on the cap 142 to an eyelet 146 on the outside of the heat shield 20. A mesh insert 148 is fitted inside the heat shield to cover the inside of the slots 140. The end cap 142 also includes a number of holes 149 and is illustrated in more detail in Figures 95A to 95E.

[0174] Referring to Figures 94 A and 94B, an alternative form of orifice plate 26 is illustrated. The orifice plate 26 still has a central opening 27, but now fits over the end of the inner tube 22. In the embodiment shown it may be held in place by a thread, however in other embodiments alternative fastening means may be used.

[0175] One example embodiment of the present invention is a mine compliant, compressed air driven, portable "air conditioner", capable of delivering super cooled additional air to a workplace. This example embodiment is a device with a 19.05mm (¾") BSP ball valve inlet that weighs approximately 6kg and can deliver chilled air at a rate starting from approximately 50m/sec and 35L/sec when supplied with 690kPa (lOOpsi) of compressed air. Nominal operating compressed air input range is 500 to 800kPa.

[0176] Other typical operating conditions for this example embodiment include cold air exiting at about 4°C wet bulb, 9°C dry bulb temperature and warm air exiting at about 26°C wet bulb, 39°C dry bulb temperature at a rate of 20m/sec and 2L/sec. The maximum surface temperature of the outer shield is about 48°C while the maximum surface temperature of the inner tube is about 68°C.

[0177] The noise level measured at the 4 cardinals, from lm and 3m distance, averaged to 87dbA at lm and 73dbA at 3m with the standard noise suppressor and exhaust extension hose and further reduces to 82dbA at lm and 75dbA at 3m when a 250mm additional noise suppressor is attached to the standard cold end noise suppressor as described previously. This has no adverse effect on the discharge deliverables.

[0178] Temperatures substantially stabilise within 2 minutes. It will be appreciated that these values are examples only and in practice will vary due to a range of factors.

[0179] Mine safety legislation typically dictates maximum surface temperatures for equipment, such as CMHSR 2001 mandating that the temperature of the hot end of the device must be below 150°C. The ventilated heat shield of the present embodiment is designed to ensure safe contact with the devices hot end, in addition to compliance to CMHSR 2001 Chapter 4 Part 2 152 which specifies the maximum allowable surface temperatures in underground coal mines. Therefore, the present invention provides a device that is suitable for use in underground mines, particularly coal mines.

[0180] The heat shield of this example embodiment also serves as the correct size to fit a standard 50.8mm (2") hose to duct away the warm discharge air from the immediate area being cooled.

[0181] The example embodiment also includes no non-conductive components. The device is fully welded and sealed for static elimination. [0182] Further, the example embodiment on final assembly has pre-set, non-adjustable cold and hot discharge temperatures to avoid the possibility of causing over temperature of the hot end in a hazardous or explosive environment.

[0183] The example embodiment has minimal noise levels when compared to current air movers, air amplifiers and Venturis. This is at least partially due to stainless steel baffled mufflers which also have the ability to add screw on extensions to further reduce noise levels. The baffles of this example embodiment are filled with Fire Retardant Anti Static (FRAS) rated foam material.

[0184] The air inlet size to this example embodiment of the device is 19.05mm (¾")· An example embodiment of a device using the variable vane accelerator 82 employs a 25.4mm (1") air inlet. An alternative example embodiment using the fixed vane accelerator 42 also has the option for a 25.4mm (1") air inlet incorporating a larger spin chamber 40. All external pipe sizes are designed with flexibility of use in mind for standard hoses, fittings pipes and mounting arrangements used in underground mining. It will be appreciated that many other alternative sizes for the inlet and other components may be used.

[0185] The example embodiment includes a magnetic adjustable mount base, however this is an optional inclusion that is provided simply for ease of use and may be redesigned or omitted in other embodiments.

[0186] The ventilated heat shroud of the example embodiment allows adequate control over the risks associated with excessive surface temperatures in hazardous areas, to negate localised safety injuries from burns, and to increase the efficiency of the device output cold temperature without changing the volume and rate of air projected from the cold end of the device.

[0187] Essentially, to achieve a colder temperature at the cold end discharge, it would be necessary either to increase the volume of hot air released from the hot end, thus reducing volume and rate of flow from the cold end, or to change the dynamics of the vane accelerator to one which in turn would reduce the volume and flow rate from the cold end by the nature of its design.

[0188] The example embodiment has uses that include, but are not limited to, maintenance on longwall faces, development faces, hard rock mining, dragline tub maintenance, conveyors; seal build sites, face drilling activities and charging faces; confined space locations; air conditioning of COBS, refuge chambers, crib rooms and chemical containers; flushing of hot humid air from water bodies or sumps with chilled air; and any other application where there is access to compressed air of the given values, with a requirement for cooling of the localised work environment.

[0189] While many parts of this specification describe the operation of the device in relation to air, it will be appreciated that the device is not limited to air, and any other suitable gas may be used.

[0190] Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention.