FIELD OF INVENTION

The present invention relates to a smoke generator and more particularly to a smoke generator that is able to produce large volumes and densities of smoke.

DESCRIPTION OF THE PRIOR ART

There are a number of ways in which artificial smoke or fog can be produced, the smoke or fog having a number of uses in a diverse set of areas including, but not limited to, military, industrial and entertainment. One of the traditional ways in which artificial smoke or fog is produced is by spraying or atomising pure mineral oil into the surrounding atmosphere. These types of smoke producing machines typically generate significant amounts of relatively large oil bubbles into the atmosphere and so are quite messy and uneconomic to run.

An example of this is that used in the process of "sky writing" wherein a plane is equipped to dispense smoke behind it and will maneuver accordingly to form letters and words to convey a message. The way in which typically smoke is produced in this manner is by delivering a smoke generating liquid into the hot exhaust pipes of the aircraft's engine where the oil is then subsequently vapourised and passed into the atmosphere.

One of the major limitations of such a system is that the quality and quantity of smoke produced is directly related to the size of the engine, as in order to produce large quantities of smoke by this method is by providing a proportionally large amount of heat energy in the way of hot exhaust gases. This then represents as somewhat of a problem when large amounts of smoke are required in that it will be necessary to employ engines of ever increasing size.

With particular reference to the art of sky writing, in order to provide or deposit the smoke at a great altitude it is then necessary to employ planes capable of

reaching the appropriate altitude and provide sufficient quantities of smoke such that the letters or symbols written by the sky writing plane are clear and legible to those viewing from the ground. This then requires that planes of substantial size be used, as the amount of smoke required is significantly greater. Small planes then can simply not provide this service and the use of the larger aircraft adds significantly to the overall cost of the operation.

There are land operated smoke generators, typically used for special effects or military operations, however, these are not generally subject to the same problems of size, due to the unlimited storage facilities of the smoke producing liquid. Moreover, with land operated smoke generators weight is not a considerable factor that needs to be taken into account to any extent.

In comparison, smoke generating machines on aircraft, of which the output of such machines is directly related to engine size, are limited with respect to the size of the smoke producing liquid reservoir such that efficiency of the smoke producing method is also important. Moreover, the added weight of the apparatus used to produce smoke adds to the running cost of the airplane and so the lighter the smoke generator is the better.

There is significant importance in obtaining larger and denser volumes of smoke using smoke generators that are simple to use and light weight.

Examples of known smoke generators, by way of mere paper publication, are those featured in US3632067 and US2422024.

Both of these descriptions refer to smoke generators that attach directly to the exhaust outlet of an engine thus, as described previously, the generated smoke output is directly related to the size of the engine. Additionally, the way in which the smoke generator is attached to the aircraft requires a complex arrangement of equipment and is not easily removable for either service or replacement.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a smoke generator that is relatively lightweight and able to produce large and dense volumes of smoke.

It is an object of the present invention to overcome, or at least substantially ameliorate, the disadvantages and shortcomings of the prior art.

Other objects and advantages of the present invention will become apparent from the following description, taking in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

SUMMARY OF THE INVENTION

According to the present invention, although this should not been seen as limiting the invention in any way, there is provided a smoke generator that includes a first tube having a heating means substantially located therein, a chamber within the first tube, the chamber having an inlet opening and an outlet opening and at least one baffle plate means disposed within.

The baffle plate means is positioned so as to provide a surface that diverts an incoming air flow entering through the inlet opening relative longitudinal to the chamber, to increase turbulence of the air flow therein. The chamber also includes a liquid delivery means for delivering a smoke generating liquid to the chamber and furthermore, there is a means for providing pressurised air into the inlet opening. As such, when in use, air when entering the first tube is heated by the heating means located therein and this then heats the at least one baffle plate means so that upon introduction of the smoke generating liquid the liquid is then atomised by striking the baffle plate means and vapourised in the chamber so as to generate a smoke that is then channeled out of the outlet opening.

In preference, the heating means comprises a burner having a burner nozzle, a burner fuel conduit connected between the burner nozzle and a fuel supply and an ignition source for igniting the fuel as it exits the burner nozzle.

In preference, the heating means is positioned near an air inlet opening of the first tube.

In preference, the chamber is further characterised in that it is substantially within a second tube, the second tube having an external diameter less than the internal diameter of the first tube such that air can pass between the first and second tubes.

In preference, the second tube is constructed from a heat conductive material to increase the rate of vapourisation within the chamber.

In preference, the baffle plate means is also constructed from a heat conductive material to increase the rate of vapourisation of the smoke generating liquid.

In preference, the liquid delivery means is positioned substantial behind a portion of the baffle plate means so that air entering an inlet opening of the second tube is at least substantially deflected by a portion of the baffle plate means prior to the liquid delivery means

In preference, the baffle plate means has an air conduit running therethrough and longitudinal with the first tube such that heated air may pass from the inlet opening to the outlet opening without coming into contact nor carrying any of the smoke generating liquid or vapour thereof.

In preference, the air conduit is coaxially aligned with the second tube so as to minimise air turbulence to air traveling through the air conduit.

In preference, the conduit has s smaller external diameter than the first tube and is held at least substantially coaxial to the first tube.

In preference, the baffle plate means comprises of at least one helical spiral plate.

In preference, the at least one helical spiral plate runs the length of the chamber.

In preference, the at least one helical spiral plate is at least substantially wrapped around the air conduit.

In preference, the baffle plate means is a plurality of substantially circular plates having at least one aperture thereon.

In preference, the apertures are offset relative to one another such that air traveling through the apertures takes a convoluted path from the inlet to the outlet.

In preference, the first tube is constructed from a heat insulating material.

In preference, there is a first helical spiral plate that runs from the inlet opening to midway along the chamber and at least two helical spiral plates that run from the middle of the chamber to the outlet opening.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, an employment of the invention is described more fully the renown for with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a smoke generator according to a preferred embodiment of the invention,

Figure 2 is a cutaway view of the smoke generator of Figure 1 ,

Figure 3 is a perspective view of the smoke generator of figure 1 in use, showing internal features.

DETAILED DESCRIPTION OF THE INVENTION

The smoke generator 10 has a first cylindrical tube 15, which forms the outer casing of the smoke generator 10. The first cylindrical tube has an inlet opening 17 and an outlet opening 19. Adjacent to the inlet opening 17 is the burner 20, consisting of a burner nozzle 22, a fuel line 24 for supplying fuel to the burner nozzle 22. The fuel line 24 being connected to a supply of fuel, which may be

directed from the aircraft's main fuel tank, or in the alternative, a separate fuel supply.

The burner nozzle 22 is held approximately central relative to the longitudinal axis of the first cylindrical tube by the burner-mounting member 25, which also accommodates the burner ignition unit 27, a piezo-electric system or other such system capable of igniting the burner fuel exiting from burner nozzle 22. Both the burner ignition unit 27 and regulation of burner fuel through the fuel line 24 can be achieved via remote operating means within the cockpit.

Thus when the aircraft is flying, air 29, upon entering through the inlet opening 17 is heated by the flame 18 to relatively high temperatures such that when the smoke generating liquid is exposed to the heated air it vapourises. The temperature of the heated air can be regulated to some extent by controlling the flame 18, by way of regulation of the burner fuel, depending on the type of smoke generating oil used.

Located generally more towards the outlet opening 19 of the first tube 15 is a second tube 30 having an outer diameter 32 less than the internal diameter 16 of the first tube 15 thus allowing air traveling through the inlet opening 17 of the first tube 15 to travel between the second tube 30 and the first tube 15 then exit through outlet 19.

The second tube 30 is held within the first tube 15 by way of mounting brackets 35, 36 and 37 and allow for the second tube 30 to be releasably secured within the first tube 15 such that it can be removed when appropriate for periodical maintenance.

Nesting within the second tube 30 is the baffle plate 40, which travels the length of the second tube from the inlet opening 41 to the outlet opening 42. The first segment 45 of the baffle plate 40 consists of a helical screw having a rib 47. At the beginning of the first segment 45, closest to the inlet opening 41 of the second tube 30 the first turn of the rib 47 shields the smoke producing oil injection line 50 so that air passing through the inlet opening 17 of the first tube

15 first strikes against the baffle plate rib section 52, which forces the air to turn in a circular manner prior to the introduction of the smoke producing oil from the injection line 50.

The incoming heated air 43 entering through the inlet opening 41 will at least in part then be traveling around the helical channel 46 and pick up the injected smoke producing oil from injection line 50 forcing it into the ribs 47 of the baffle plate 40 as well as the internal surface 33 of the second tube 30. In this manner then the introduced smoke producing oil is efficiently atomised via mechanical forces.

In addition, the helical baffle plate 40 is wrapped around a third cylindrical tube 57 running the length of the second tube 30, thus forming the central axis of the baffle plate 40. Tube 57 is hollow, thus allowing heated air to pass through it, the heat then being transferred to the ribs 47 along the its length.

In this way then, prior to the introduction of smoke generating liquid through the injection line 50, the ribs 47 of the baffle plate 40 are heated up to temperatures sufficient to facilitate in the vapourisation of the smoke generating liquid upon contact with the ribs 47.

The second segment 60 of the baffle plate 40 is where an additional helical channel 62 is positioned, which adds a further means of vapourising and atomizing any remaining smoke generating liquid.

The smoke thus produced in the second tube 30 then exits the outlet openings 19 and 42, smoke cloud 65where turbulence, created by the interaction of the smoke traveling though the second tube 30 and the heated air passing through aperture 31 and through the third tube 57, further acts to vapourise and remaining un vapourised-atomised smoke producing oil and disseminate the smoke.

This then is an important feature of the invention, where there are several stages where the smoke generating liquid can be vapourised and/or atomized.

As the present invention in terms of smoke output is thus not reliant on the size of the engine and the overall efficiency is very high compared to current methods of generating smoke from aircraft.

The smoke generating apparatus 10 can be fitted to any aircraft with little modification, by way of mounting brackets 18 to an aircrafts fuselage. The burner fuel line 24 and smoke generating line 50 can then be connected to their respective supplies in an appropriate manner, be it to an inbuilt fuel/smoke generating liquid reservoir system or an add-on system attached directly to the smoke producing apparatus 10.

The smoke generator as described may also be controlled via a computer, to control accurately the production of smoke via control of preferably the addition of the smoke generating liquid though line 50.

Additionally, it would be well appreciated by a person skilled in the art that the apparatus as described above can also be used in other situations apart from that involving aircraft. For example, air can be forced in be a high-speed fan, or other such method, into the first tube 15 and the system mounted of a vehicle, this then would provide for a mobile ground system.

Although the invention has been hearing shown and described in one is conceived to be the most practical and preferred embodiment, it is recognized that departures can be made within the scope of the invention, which is not to be limited to the details described herein but it is to be accorded the full scope of the appended claims so as to embrace any and all equivalent devices and apparatus.