WO2000036337A1 - Torches and portable power sources - Google Patents

Abstract

A torch (1) comprises a light emitter (2), means for receiving fuel (28), a motor (8) for converting the chemical energy of the fuel to mechanical energy and a generator (4) for converting the mechanical energy produced by the motor (8) to electrical energy to power the light emitter (2). The motor (8) has a recommended operating range which includes a rate of at least 10,000 r.p.m.

Description

TORCHES AND PORTABLE POWER SOURCES

The present invention relates to portable power sources and, in particular, to portable light sources such as search lamps, torches, lanterns and the like, hereinafter referred to as torches. The invention can be applied generally to domestic torches, miners style headlamp torches, hand-held miners lamps and hurricane

(storm) lantern variations and equipment considered to suffer from similar limitations as torches described below.

The term portable is meant in the torch application sense of the word as distinct from where portable actually only means luggable.

In general, conventional torches compromise between brightness and duration of light emission to remain hand portable. Such conventional torches which incorporate a battery power source can be disappointing in many applications particularly due to the limited battery lifetime and the brightness of the light emitter which can be powered by a portable battery unit. In general, batteries have a poor energy/mass/volume ratio.

Battery expense makes torches costly to run unless rechargeable types are used. So called fast chargers still take several minutes and most take at least an hour to recharge . Frequent rapid charging shortens the service life of batteries. In many circumstances the recharge time and availability of a suitable supply in the field of use rule out this option. Primary cells perform poorly under heavy load so powerful torches are restricted to intermittent use if the batteries are to be fully utilised. Secondary cells perform better under heavy load but have less capacity than good primary types and again are restricted to intermittent use.

Furthermore, visual inspection usually provides little or no indication of battery status or previous usage. Some battery types self discharge during storage making torches disappointing in practical service and when really needed. In practical terms this usually means that torches only work if they are used regularly.

Despite a century of torch and battery development a simple candle remains in many ways a more practical light source than a torch. A small Tea light candle providing sustained light for 4 or 5 hours with indication of time remaining as well as constant light output remains superior to most torches in a sustained power cut .

In many areas, for example camping and caravanning, the candle and portable gas mantle lamp remain essential equipment due to the poor performance of torches.

Given that naked flames often remain preferable over the electric torch despite their dangers, inconvenience and lack of versatility it is clear the electric torch has failed to fulfil despite being around for 100 years.

It is clear from the above discussion that the energy reserve of the naked flame light coupled to an electric light source would have much to commend it as this would solve the feeble performance of the torch allowing it to be optimised for brightness or duration.

More efficient light emitters such as fluorescent or high intensity discharge (hid) lamps have had little impact on torch development due to the heavy load they would exert on a torch battery.

Fluorescent discharge lamps with an electronic circuit improve matters but practical torches still can only utilise low power lamps and most conventional torches remain feeble in comparison, for example, to a 60 watt mains bulb. Efficient High Intensity Discharge (H.I.D.) lamps have a better point source but still provide a heavy load to a torch battery.

The present invention has been made from a consideration of the disadvantages with known torches and in order to provide an improved torch or portable power source which can provide sufficient power to support a wide range of light emitters including fluorescent or h.i.d lamps yet which remains sufficiently portable in comparison with conventional torches. These gains being so appreciable as to allow the use of spare power to be wholly or partially utilised to power ancillary equipment.

According to the invention there is provided a torch comprising a light emitter, means for receiving fuel, a motor for converting the chemical energy of the fuel to mechanical energy and a generator for converting the mechanical energy produced by the motor to electrical energy to power the light emitter characterised in that said motor comprises a motor having a recommended operating range which includes a rate of at least 10,000 r.p.m. Thus, in use, the motor can be operated from idle up to at least 10,000 r.p.m. Preferably, components of the torch are housed in a portable and/or hand-held housing unit. Preferably, the means for receiving fuel comprises a fuel reservoir such as a tank.

Preferably, the light emitter is electrically coupled to said generator.

Preferably, the generator comprises a dynamo or alternator which may produce either alternating current or direct current . Any suitable type of generator may be used. The light emitter may comprise any suitable type of lamp such as an electric bulb, a lantern, a fluorescent or high intensity discharge lamp or the like.

Preferably, the motor comprises an internal - combustion engine. Alternatively, the motor may comprise an external combustion engine such as a steam engine.

Preferably, the fuel receiving means or fuel reservoir, the motor, the generator and/or the light emitter are mounted on a chassis.

Preferably, the chassis is adapted to be located in and releasably secured in a housing which forms the main body of the torch. Preferably, an exhaust outlet is provided on the housing.

The housing may have any suitable form but is preferably in the shape of a conventional hand-held torch or lantern. The housing may be adapted for example to be secured to a miner's headgear or belt.

Preferably, the housing is provided with a releasable cap to facilitate refuelling the tank. The torch may be provided with an auxiliary battery source .

The torch may be adapted to operate using any suitable fuel but is preferably adapted to be run on petrol .

Preferably, the torch is provided with an electrical switch for switching on or off the electrical supply to the light emitter. Preferably, the torch comprises an auxiliary power output terminal. Power outlets can also be provided for other equipment and a miners headlamp or handlamp.

Preferably, the motor is provided with a control valve or throttle to control the flow of fuel or steam in the engine. A suitable control lever or the like may be used to operate the valve. Preferably, the valve allows the brightness of the light emitter to be varied by varying the frequency of the motor. For example, when the engine is idle, the light output may be dull whereas brighter output may be obtained by increasing the engine frequency. Appropriate electronic circuitry may be used to vary or adjust the brightness of the light emitter.

Thus, in a torch of the invention, the battery may be replaced or supplemented with a small motor generator unit of such size as to be hand portable and provide significant improvement in the energy/weight ratio of the torch, due to the recoverable energy stored in fuel far exceeding batteries for a given volume or mass .

In an alternative embodiment, a steam engine may be used and may be more suitable for enclosed/indoor areas as such an embodiment can have green emissions can be very quiet and still offer advantages over batteries.

The use of a motor to power an electricity generator to power a torch lamp has significant advantages. The energy stored in the fuel far exceeds that which can be stored in batteries and so allows significant improvements in power output and/or duration in use. Thus, replacing or supplementing the battery by a small motor generator unit improves torch performance.

According to a second aspect of the invention there is provided a portable power source comprising means for receiving fuel, a motor for converting the chemical energy of the fuel to mechanical energy and a generator for converting the mechanical energy produced by the motor to electrical energy characterised in that said motor comprises a motor having a recommended operating range which includes a rate of at least 10,000 r.p.m.

The motor or engine size is preferably in the range of 0 to 15 cc and most preferably in the region of 0.1 to 1.5 cc . Preferably, the motor is adapted to run on petrol although the torch of the invention may be run on glow plug fuel or diesel if desired. Preferably, the engine would have a dry weight of less than about 1 kg, more preferably a weight in the range of 0.1 to 1 kg.

Preferably, the fuel reservoir has a capacity of less than 1 litre, typically about 0.5 litres and most preferably less than 250 cc capacity. The maximum reservoir capacity will typically be used while maintaining the desired portability. Preferably, the motor comprises a miniature or micro engine and is capable of operating at ultra high r.p.m. ie above 10,000 r.p.m. such as a model engine. The highest recommended operating rate of a normal engine is typically much less than 8,000 r.p.m. Preferably, the motor has a recommended operating range which includes a rate of at least 15,000 r.p.m. Preferably, the motor has a recommended operating rate in the range 10,000 to 100,000 r.p.m. The recommended operating rate may be in the range 20,000 - 85,000 r.p.m.

A torch of the invention may have the following specific advantages : -

1. A motor - generator torch or torch of the invention delivers more total Energy ( ) per unit volume of fuel than a battery torch. = Volts (V) x Amps (I) x Time (t) = Vlt

2. A motor - generator torch or torch of the invention delivers more total Energy ( ) per unit weight of fuel than a battery torch. W = Vlt

3. The energy density of motor fuel far exceeds battery energy density allowing torch power outputs and/or duration to be considerably increased and still remain hand portable.

4. The total energy available allows more efficient light sources to be used that cannot normally be sustained from batteries. Example:- High Intensity Discharge (H.I.D.) Lamps. 5. Motor - generator torches or torches of the invention provide sustainable torch lamp powers not achievable with battery torches.

6. Motor - generator torches or torches of the invention provide full output power until all fuel is exhausted, unlike battery powered torches which get gradually dimmer as the battery runs down.

7. Motor generator torches or torches of the invention don't leave the user with a useless by product like flat batteries for disposal .

8. Motor generator torches or torches of the invention are refuelled quicker than rechargeable battery torches .

9. Motor generator torches or torches of the invention allow the user to carry spare fuel whereas rechargeable battery torches require access to an electricity supply.

10. Motor generator torches or torches of the invention allow the user to carry spare fuel of greater energy density than batteries and do not result in user inconveniences of carrying low energy density primary batteries that require disposal or recharging delays of secondary batteries .

11. Fuel cell torches are quiet to operate and cleaner environmentally.

12. Fuels, especially liquid fuels, can be accommodated in any suitable shape reservoir so that a torch of the invention can be made compact by adapting the reservoir size and shape around the other components of the torch. By contrast, batteries are restricted as to shape and size.

13. Fuel is much cheaper per watt output than primary batteries so that a torch of the invention is much more economical and efficient to operate.

14. The space saved by using physically smaller engines and generators leaves more space for fuel or other equipment .

Prior art patent descriptions for smaller lighter power generation go to great lengths to describe how they intend to do this using engines not fit for the purpose. Much is made of the use of smaller lighter generators using better smaller magnets and of course electronics none of which is particularly relevant when the orthodox engine/power source is the main unsuitable component, being altogether too cumbersome. Furthermore, utilising unsuitable engines causes larger generators to be used as well, even with special magnets and/or electronics.

Such prior art portable generators actually result in a strimmer or lawnmower engine with a generator fitted to it, resulting in devices that are essentially static and at best only luggable. Much is made of the use of smaller generators using high energy product magnets, for example in O96/09679, but little or no attention is paid to the unsuitable conventional engines preventing these devices making the grade to a torch or portable device as defined above .

Thus, devices claiming to be portable are only luggable and when implemented produce devices of several kilograms and even the best examples remain cumbersome requiring to be transported as a bulky back pack or shoulder bag. Others have a handle for transporting between places of use but are totally static when in use and none are suitable for incorporation into other portable equipment without serious detriment to target equipment portability.

The power available from a given engine is mainly due to the rate the fuel is burned and not the physical size of the engine .

Hence, very small engines capable of much higher r.p.m. such as at least 10,000 r.p.m. can match and exceed the performance of conventional counterparts and take much less space, weight and bulk. Furthermore, increased r.p.m. also allows the use of much smaller lighter generators so a double saving in weight and bulk is achieved without recourse to electronics, special magnets or materials. Although these can be utilised if required.

Hence, very small high r.pm. engines achieve very significant power levels enabling smaller lighter generators to be used creating space, weight and size savings for more fuel and/or ancillary equipment. This approach enables generators small enough for incorporation into portable equipment and for this equipment to remain portable and in many cases have no affect on equipment portability other than to improve it.

Engine efficiency plays a part but compared to batteries the recoverable energy from fuel per unit volume and/or unit mass is so great that even inefficient engines coupled to inefficient generators will still easily outperform a battery torch. Furthermore, the very significant size and weight savings on the motor and also generator allow much larger fuel tanks to be used so high efficiency is helpful but not essential for a practical device .

By making the engine fit the application as opposed to making the application fit the engine, the torch and similarly debilitated applications prevented by conventional approaches, can fulfil much more of its potential, albeit fifty years late.

Conventional prior art portable lights such as described in US 4464706 using TELE-LITE TEX350 and generators such as the Coleman Powermate Inc . LIGHT WEIGHT GENSET described in WO96/09679 utilise engines like the TECUMSEH TC300 2.0 horsepower, 49cc two stroke which weighs 3.4 kg and has no performance data quoted above 6000 r.p.m, having a recommended operating range of 4,000 to 6,000 r.p.m.

Implementing these principles the TECUMSEH TC300 could be replaced by a 3.5cc engine developing 2.1 horsepower at 30,000 r.p.m. and weighing less than 0.3kg with a practical r.p.m. range of 3000-38000 such as the Thunder Tiger PR021 glow engine.

If something a little more sedate is required a MDS68 glow engine 11.15 cc develops 2.21 horsepower at 18000 r.p.m and weighs less than 0.6kg.

These engines run on glow fuel but can be adapted for other fuels. Some degradation of performance can occur but plenty of portable power will remain. Torch lamp sizes can now be chosen to fit the need of the application instead of the needs of the battery.

The principles discussed can be implemented with a gas turbine engine or a jet engine optimised for power generation sometimes called a shaft turbine. Turbine compressor changes are sometimes implemented when utilised as a shaft turbine .

The FD3/67 series gas turbine engines can produce around 2 kilowatts of power at very high r.p.m. The unit measures 220 mm long by 110 mm diameter and weighs 0.78 kg. The fuel and lubrication system add a further 0.15- 0.3 kg. However, the jet exhaust system is not required for propulsion and its removal will make the engine shorter and lighter. So the gas turbine should weigh less than 1.0 kg and measure 180 mm in length, possibly less. The practical r.p.m. range is 20000-85000. The FDR/67 series gas turbines is quiet compared to other turbines however much more powerful types almost identical in size and marginally heavier could also be use, such as the KJ66. Driving the generator as a motor would make starting the gas turbine easier.

Gas turbines can be adapted to run on almost any liquid fuel such as paraffin, petrol, diesel, methanol etc and also run very well on gas such as butane or propane. Diesel fuels high energy content makes for smaller fuel tanks and also gas turbines designed for liquid fuel can be persuaded to run on liquid gas.

Engines of less than lcc, weighing around 60 grams, will outperform all but the very best battery torches. In fact battery performance is so feeble that these same engines can still match batteries when running at similar r.p.m. as orthodox counterparts.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: -

Figure 1 is a schematic view showing the various components of a torch of the invention;

Figure 2 (a) is a side view of one embodiment of torch of the invention;

Figure 2 (b) and 2 (c) are end and plan views respectively of the torch of figure 2 (a) ;

Figure 3 (a) - (c) are plan, side and end views respectively of the torch of figure 2 mounted in a torch housing;

Figure 4(a) - (d) are plan, side, rear end and front end views respectively corresponding to figure 3 but showing less hidden detail for clarity;

Figure 5(a) - (c) are plan, side and end views respectively of the torch of figure 2 mounted in a lantern housing; and

Figure 6(a) - (d) are plan, side, rear end and front end views respectively corresponding to figure 5 but showing less hidden detail for clarity.

Referring to figure 1, a torch 1 of the invention comprises a light emitter or lamp 2 electrically connected to be powered by a generator 4 which is driven by a motor 8 through power coupling 10. Typically, a lamp on/off switch 12 is provided for switching the light emitter 2 on or off as required. An auxiliary power on/off switch 14 allows power to be switched on or off to an auxiliary power connector 16 which allows other electric devices to be powered via the portable light source if desired. Similarly an optional battery 18 and on/off battery switch 20 may be provided to allow battery back-up if desired.

Referring to figure 2, a torch 10 of the invention is shown mounted on a chassis 22. The torch comprises a lamp 2 mounted on a lampholder 24 which is supported by a bracket 26 on the chassis 22. A fuel tank 28 receives fuel through inlet 30 for driving the engine or motor 8 which causes the engine/motor shaft 34 to rotate and consequently rotate the generator/dynamo shaft 36 of the generator dynamo 4. The shafts 34, 36 are mechanically coupled via coupling 6. The fuel or combustion system 32 is provided in the engine/motor 8. It will be appreciated that, although a box shaped fuel tank is shown, the fuel tank may be shaped to fit in around the other components to improve compactness.

A starter handle 38 and recoil starter 40 are also provided on the engine 8. A suitable exhaust system 42 having an exhaust outlet 44 is provided.

The lamp switch 12, power outlet switch 14 and power outlet socket 16 are provided on a housing 46.

Referring to figures 3 and 4, the torch mounted on the chassis as shown in figure 2 is mounted in a torch housing 48. The bezel 50 is screw threaded 51 onto the main body 52 of the housing and holds a reflector 54 and glass plate 56 in position as conventional. The bezel is unscrewed and the cover plate 58 is removed to allow the chassis to slide inside the main housing body 52. The chassis is held in place by the reflector when the bezel is screwed onto the torch body. The chassis is also secured by screws or the like (not shown) . When the chassis is in place, the cover plate 58 and then the handle 60 are fitted to the main body. A cutout or recess in the torch body provides access to the switches and connectors. A removable and/or adjustable bracket handle 62 may be provided for carrying and/or fastening the torch to a stand or other fixture. The handle 62 is adjustably and/or removably secured to the housing 48 by means of screw knobs 64 received through apertures in the handle 62 and in threaded brackets 66 provided on the housing.

Referring to figures 5 and 6, the torch mounted on the chassis as shown in figure 2 is mounted in a lantern housing. The lantern housing features are substantially similar to the torch housing described with reference to figure 3. However, for the lantern, the reflector is removed and a glass and/or plastic cover 68 is fitted to the housing to form a lantern style headlamp. The bracket handle is more suitable for larger semi-portable lanterns and torches which may have large fuel reserves for hours or days of use or simply for very powerful lamps.

Retaining an auxiliary battery as shown in figure 1 allows the torches of the invention to have electric start by either driving the generator/dynamo or separate starter motor. The torch could also run for short periods without the engine. The engine can also run for recharge and/or auxiliary power without a lamp running. This should improve starting from the battery. It will be seen that using a torch of the present invention, a small quantity of fuel can be used to power a high intensity, stable light. Such torches can be used for domestic applications or in industrial situations.

Thus, it will be seen that an engine size of only a few cc will give a very bright torch. For example, an 0.8 cc model engine size could be expected to achieve about 60 watts output with glow plug fuel. Preferably, these very small engines would be converted to run on petrol or other filling station fuels where necessary as the convenience of filling station fuels is considered worthwhile to the user.

By contrast, a large 12v 6.5 amp per hour battery of about 2.2 kg weight would only give about 50 watt output for an hour.

Any suitable fuel powered engine may be used, including diesel type engines which, although slower, are suitable for use in a torch of the invention.

It will be appreciated that the present invention is not intended to be restricted to the details of the above embodiments which are described by way of example only.

The portable power source of the invention may have any of the features described above with reference to a torch.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification

(including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A torch comprising a light emitter, means for receiving fuel, a motor for converting the chemical energy of the fuel to mechanical energy and a generator for converting the mechanical energy produced by the motor to electrical energy, to power the light emitter characterised in that said motor comprises a motor having a recommended operating range which includes a rate of at least 10,000 r.p.m.

2. A torch according to claim 1, wherein the torch is contained in a portable, housing unit.

3. A torch according to any preceding claim wherein the motor has a recommended operating rate in the range 10,000 r.p.m. to 100,000 r.p.m.

4. A torch according to any preceding claim, wherein the motor comprises an internal-combustion engine.

5. A torch according to any preceding claim, wherein the fuel receiving means, the motor, the generator and/or the light emitter are mounted on a chassis.

6. A torch according to claim 5, wherein the chassis is adapted to be located in and releasably secured in a housing which forms the main body of the torch.

7. A torch according to any preceding claim, wherein the torch is provided with an electrical switch for switching on or off the electrical supply to the light emitter.

8. A torch according to any preceding claim, wherein the torch comprises an auxiliary power output terminal.

9. A torch according to any preceding claim, wherein the motor is provided with a control valve or throttle to control the flow of fuel in the engine.

10. A torch according to claim 9, wherein the valve allows the brightness of the light emitter to be varied by varying the frequency of the motor.

11. A portable power source comprising means for receiving fuel, a motor for converting the chemical energy of the fuel to mechanical energy and a generator for converting the mechanical energy produced by the motor to electrical energy characterised in that said motor comprises a motor having a recommended operating range which includes a rate of at least 10,000 r.p.m.