GB2122264A - Improvements in or relating to hot venturi tube or hot chamber thermal engines - Google Patents

Abstract

The working fluid is pressurized by jet type air compressor 5 and cooled by water circulating through jackets 3 and 4 and heat exchanger 13, in which steam is generated from said water and thereafter led into jacket 2, which reheats the cooled compressed air working fluid leaving said air compressor and expanding to utilization in propulsion nozzle 18 through the divergency of hot tube cum chamber 1, which incorporates said jacket 2. Modified plants diffuse said steam with said expanding working fluid or employ a gaseous heat conveying medium or a thermo- electric heat exchange means. The condensate water formed in jacket 2 is fed by pump 7 back into assemblies 3, 4 and 13. <IMAGE>

Description

SPECIFICATION Improvements in or relating to hot tube or chamber engines This invention concerns improvements in or relating to hot tube or chamber engines.

More specifically, these improvements relate to such engines comprising one or more venturi tubes or chambers receiving air under pressure, from a jet type air compressor system and employing a thermodynamic cycle in which useful power is produced by a process of heat transference, partially effected by'a circulating fluid, from the air under pressure feeding said venturi tube(s) or chamber(s) to the air expanding through them, but not exclusively so.

In my previous designs for such thermal engines, I have disclosed heat conveying circulating fluid methods utilizing molten metal convecting in the hollow walls of their venturi tubes or chambers for heat transference from the air under compression in their air compressors back to this air during its subsequent expansion in said venturi tubes or chambers. These methods have the disadvantage that the operating temperature of the venturi tubes or chambers must be comparatively high to obtain effective circulation of the molten metal in their hollow walls.

Other generally similar thermal engines employ a circulating gaseous fluid which is alternately compressed and expanded in their heat transference equipment, to convey heat from the air under compression to the same air expanding through the divergent sections of their venturi tubes. In these engines, a considerable proportion of their total power output may be utilized to compress the heat conveying fluid which would reduce the useful work output obtainable.

The invention includes among its objects and advantages, the provision of a method and means for operating hot venturi tube and hot chamber thermal engines of the kind employing a circulating fluid to assist the heat transference from and back to their primary working medium efficiently at relatively low venturi tube or chamber temperatures and without the expenditure of large amounts of energy to pump the heat conveying circulating fluid through its circuit.

In such engines according to the present invention, simple means such as an engine driven displacement pump or the pressure of the relative wind, not involving as an essential requirement of said means any appreciable compressive effort by said pump or wind, are utilized to circulate the heat conveying fluid, which is a gas, such as air or steam at atmospheric pressure, a liquid such as water, or even steam and its liquid, in the preferred method of operation.The power consumption of said means could therefore, be less than that necessary if the heat conveying fluid was compressed by it, and the need for a high operating temperature in the walls of the venturi tubes or chambers is avoided by the use of more volatile and amenable heat conveying fluids, in said walls, the theoretical positive work output obtainable being higher than the useful work output of comparable similar engines of earlier design.

With my hot venturi tube and hot chamber engines in which the heat conveying fluid circulated through the hollow walls of their venturi tubes and chambers is molten metal, only a limited amount of heat transference, which is their source of power, is effected by said fluid.

This is not so with thermal engines according to this invention, in which the heat transference is almost entirely carried out by the circulated heat conveying fluid and may extend to include heat conveyance from assemblies, such as air compressors having several stages and their entraining tubes, embodied in said engines.

However, this does not alter the method of power production utilized by these engines, which remains basically the same as that employed by my earlier such hot tube or hot chamber engines, i.e., heat transference from the air under compression, back to said air upon its expansion in the divergent sections of their venturi tubes or chambers.

Since the process of heat transference by the circulating fluid is essentially one of heat exchange, it may be convenient to use heat exchange means, such as jacket or tubular devices, of another construction which may be preferential and considered advantageous, e.g.

from the point of view of the thermal efficiency of the engine, for this purpose, in particular embodiments of the invention, whose scope comprehends such modifications and improved methods of heat transference. Such devices are either closed system or open circuit units.

Supposing the heat conveying fluid is a liquid this fluid could convect, but, to obtain the greatest thermal efficiency or heat transference by said liquid, it would be preferable to pump it through its circuit. Conversely, the liquid may be allowed to boil and the steam given off by it utilized to transfer the heat.A divided circuit for said fluid, such as two separate heat exchangers, one for the liquid and the other for the steam, connected by a steam delivery pipe and a condensate return conduit and pump is provided to permit this method of operation, in which, unless a liquid volatile at atmospheric temperature is evaporated to form the steam, means such as an electric heater placed in the heat exchanger containing the liquid, for preheating the liquid to boiling temperature prior to starting the engine's working cycle, to enable the heat transference process to function, is desirably incorporated.

To increase the power of these engines or merely to ensure ease of starting their working cycle, means such as the provision of an electric heater placed in the heat conveying fluid stream or streams directed over the divergent portions of the venturi tubes or chambers of the engines, to additionally heat this fluid continuously or intermittently, e.g. to increase the Brake Horse Power of the engine or merely to facilitate the starting of its working cycle respectively, further comprises the invention.

A significant improvement in the thermal efficiency, whichdepends on the effectiveness of the heat transference process, of the engines can be achieved by the extension of the heat transference means to encompass the complete air compressor assemblies, where these air compressors having a plurality of compression stages, it being practical to transfer large amounts of heat from the air under compression, in this way.

Another appreciable increase in the thermal efficiency of jet propulsion unit embodiments of the invention, which may be ram jet units, furthermore, can be obtained by also passing heat from the ram air entering the entraining ducts of the air compression systems of these engines, their heat transference means being suitably constructed to induce this extra heat withdrawal.

Such extra heat withdrawal might be at a lower temperature than that of the primary heat transference and act only to preheat the circulating fluid of the latter means or process.

Severai heat transference means operating at the same or different temperatures can be embodied in a single engine, progressive heat transference methods employing the latter mode of operation being practicable for use with said means.

In practice, vaporizing liquid heat conveying fluids may have a considerable vapour pressure, but this would not alter the amount of work done by the circulating pump, since the pressure on both sides of this pump would be the same. This being so, with these methods the fluid circulating pump can be a steam driven unit, such as an automatic injector or a mechanical pump, operated by some of said vapour. The circulating pump work, where heat transference methods comprising the invention, utilizing a pressurized gaseous heat conveying medium are featured, would similarly remain unaltered. An ejector pump operated by said pressurized fluid can be used to circulate this fluid.

With ambient air fed heat transference means, the circulating fluid pump is a fan or an air jet ejector operated by the working fluid jet or jets exhausting from the engine's discharge nozzle system and drawing said air through an open circuit. Air or gas filled unpressurized such means having a closed circuit method of operation circulate their fluid by means, such as a fan.

Alternatively, the heat conveying fluid is circulated by a mechanical pump of another kind, such as an auxiliary power unit or air screw driven sliding vane, gear wheel or piston pump, or, in air breathing open circuit heat transference means, by the working medium compressor and its entraining action or suction, or by an auxiliary ejector operated by only a portion of said working medium and incorporated for this purpose exclusively or combined with an expansion device, such as a thrust producing nozzle or an air turbine generating power to drive ancilliaries, fed with the ejected air.

Embodiments of the invention having a plurality of venturi tubes or chambers induce heat transference by means either separate for each said tube or chamber or common to all such assemblies.

Control of the power output or the thrust for propulsion or lift of these engines is, in most instances, obtained by methods, such as regulation of the working fluid supply to the engine or its compressor or regulation of the speed of the heat conveying fluid pump and thus the rate of heat transference, or the flow of heat conveying fluid through connecting channels of the heat transference means.

An electronic heat transference means comprising an electric generator operating to produce electricity directly from e.g. the hot fluid of the primary heat transference means, and utilize this electricity to energise an electric heating device or devices placed and functioning to heat the working fluid stream or streams expanding through the divergent sections of the engine's venturi tube(s) or its chamber(s), at least supplements the action of said primary heat transference means, in a refinement of the apparatus.

A choice of either of two different kinds of electric generator is optionally provided with this electronic heat transference means, one such generator being a thermocouple and the other an electronic alternator or various possible detail design.

The invention additionally encompasses modifications viz. the application of combinations of the heat transference methods briefly described in the preceding paragraphs and the utilization of the primary working fluid of specific embodiments, to a variable extent, also as the heat conveying fluid of their heat transference means.

The cooling of the working fluid under compression may or may not proceed to liquefaction, the use of any gas or gaseous medium, for example air or steam, as said fluid, being contemplated.

Finaliy, I provide means to induce the heat transference consisting, in part, of the reheating of the compressed cooled working fluid expanding through the divergency of the hot tube or chamber by cooling fluid steam mixed for example in said divergency by its admission thereto, directly with said cooled working fluid. In an example, said steam is also utilized to compress the working fluid.

Further, it will be fully understood by anyone with a knowledge of the art, that the foregoing generate statement of the invention in no way obviates the practicability of its application to broadly similar thermal engines in which a significant proportion of the total heat transference for useful power production is obtained by the use of existing methods, such as heat conduction through the thick walls of the engine's venturi tubes or chambers from their convergent sections to their divergent sections, or in which the working fluid medium compression is carried out exclusively or partially by a mechanical compressor.

According to the invention, a hot venturi tube or hot chamber thermal engine comprising one or more venturi tubes or chambers receiving a working fluid, such as air, at a pressure sufficiently high to increase substantially its temperature and employing a thermodynamic cycle in which useful power is produced by a process of heat transference from the working fluid under compression feeding said venturi tube(s) or chamber(s), back to this same fluid upon its expansion through their divergent section(s), is characterised in that in said process, a part at least of the heat transference is effected by a comparatively light heat conveying fluid, such as air or water, circulated by for example, a mechanical pump, through a heat exchange device or devices constituting, with said heat conveying fluid and its displacement provision, the means for said partial heat transference for power production.

According to a feature of the invention, a hot venturi tube or hot chamber thermal engine includes heat transference means operating to generate electronically, electricity from heat derived from the compressed or partly compressed working fluid of the engine and utilize this electricity to heat said working fluid during its subsequent expansion.

In order that the objects and advantages of the invention may be made more clearly apparent, some examples will now be described with reference to the accompanying drawing, which shows a hot venturi tube cum chamber jet pro pulsion unit according to the invention.

This jet propulsion unit comprises a venturi tube cum chamber 1, which has a heat transference means consisting primarily of two jackets 2 and 3 and, in the lower half of the drawing, a third jacket 4, and a jet type air compressor 5 having, in the top half section of the figure, a single stage and, in the lower half of said figure, two stages, which compresses the air feeding said tube or chamber.

The jackets 3 and 4 contain water which acts as a coolant for the convergent inlet of tube or chamber 1 and air compressor 5 respectively, and forms steam which is led e.g. by pipe 6, into jacket 2 and heats the divergent downstream portion of said tube or chamber and the cooled compressed air received from said air compressor and said inlet, expanding through this portion of said tube or chamber. The steam led into jacket 2 condenses and the condensate is fed back into jackets 3 and 4 by a pump 7. If desired, heat may be transferred in a similar manner, by a further jacket 8 operating to cool the air, which may be compressed by ram action at high speeds above mach 1, entrained by air compressor 5 and generates more steam which would also be led into jacket 2. Alternatively, the jacket 8 may act merely to preheat the condensate water fed into jackets 3 and 4.Spring loaded valves 9 and 10 and an operable valve 11 respectively, release surplus steam from jackets 3 and 4, which are connected by a steam pipe 12, admit ambient air into jackets 2, 3 and 4 when the engine is in disuse, to destroy the vacuum created therein by steam condensation, and evacuate this air by steam pressure when starting the engine's working cycle, to permit steam to enter jacket 2.

A multitubular heat exchanger 13 placed in the air entraining tube connecting the first and second stages of the air compressor 5 shown in the lower half of the figure, is connected to jacket 4 by a water feed pipe 14 and at its top extremity, by a steam pipe not shown, and helps to cool the compressed air entrained through said tube. Preheating of the water in jackets 3 and 4 to boiling temperature, to raise steam prior to starting the engine's working cycle, may be necessary and would be a disadvantage of this system of heat transference.

Consequently, it may be preferred to substitute a liquid having a comparatively low boiling temperature, such as carbon-dioxide or the refrigerants Cryogen and Freon, and not requiring such preheating, for the water in jackets 3 and 4 and assembly 13. A device, such as an electric immersion heater, however, can be provided in all cases to help the initial steam formation in said jackets and assembly.

Instead of water, jacket 3 may receive only steam from jacket 4 and heat exchanger 1 3 and act, by directing this steam over the air inlet end of tube or chamber 1, to superheat this steam before its passage into jacket 2, as weil as to cool said tube or chamber end which would be at high temperature and forms the final air compression duct of the air compressor 5, in the arrangement shown in the lower half of the drawing.

Optionally, the steam led into jacket 2 is super heated by another method, such as combustion gas or electric heating of the steam pipe 6.

A heat exchanger, for example a coiled tube or a multitubular such device, incorporated in the divergent part of tube or chamber 1 and fed with steam by pipe 6 is preferred as the means for heating the cooled compressed air expanding through this tube divergency, but it is practical to use both jacket 2 and such a device for said purpose or even steam e.g. from jacket 3, mixed with said air.

The provision of a reservoir of the requisite liquid and a feed arrangement, such as a gravity or a pumped supply system, may be necessary to replace any of the coolant lost by leakage or other causes from the jackets 2, 3 and 4.

Some of the heat of the air compressed by air compressor 5 is transferred by electronic means, the apparatus consisting of an oscillatory circuit 1 5 operating at infra red frequency and incorporating a rectifier 16, (such as a mercury arc or transistor unit or a so called cavity magnetron valve suitably arranged) passing current to an electric resistance coil 1 7 placed in the divergency of tube or chamber 1 and acting to help reheat the cooled air fed into said divergency by said air compressor. The lower part of the oscillatory circuit 1 5 is located in jacket 3 and is heated by the fluids (water and steam) contained therein and is activated by this heat, which is the source of the electrical energy of said circuit.

Possibly this apparatus would function more efficiently if this part of the circuit 1 5 was made of a metal or a substance passing little of its heat to the remainder of said circuit, whose electrical resistance would be increased by such heating. If desired, the rectifier 1 6 may be omitted and current passed directly from the oscillatory circuit to coil 17. A plasma producing device can replace coil 17, when preferential or said coil may be an induction unit. The portion of the oscillatory circuit placed in jacket 3 may need to be insulated electrically from said jacket and its fluid contents, but not thermally so. This insulation might consist of a ceramic or synthetic sapphire or ruby coating conducting heat to said circuit portion, possibly enclosed in a metallic sheath, such as a copper or aluminium tube.To preheat the water in jackets 3 and 4 previous to starting the engine's working cycle, the said lower part of circuit 1 5 could be supplied with electricity by a dynamo or a battery and act as an immersion heater. Said part of circuit 15 may have a low, medium or high electrical resistance, depending on the design of said circuit, which is shown very diagrammatically, or may be both electrically and thermally insulated, except for the passage to it of infra red heat radiation, and operate by induction of electromagnetic or electrostatic kind. In practice, such an induction operated oscillatory circuit portion forms a coil, such as a copper of aluminium wire coal or a similar metal plate unit, wrapped round the inlet end of tube or chamber 1 and air compressor 5.

A modified electrical heat transference means employs a thermocoupled similarly placed and heated by the fluids in jacket 3 and 4, to supply electricity to the heating coil 1 7.

The oscillatory circuit 1 5 may function more effectively or perhaps only if excited initially or continuously by a secondary oscillator not illustrated, operated by e.g. some of the electric current from said circuit.

The reheated air is mostly exhausted from tube or chamber 1 through an adjustable nozzle 1 8 to produce a reactive thrust, although some of this air is directed by conduits 1 9 to nozzles 20, which are the power nozzles of air compressor 5 and exhaust respectively, through the convergency of said tube or chamber and the air duct 21, which is also convergent, of the first stage of said air compressor.The inlet ends of conduit 1 9 project into tube 1 and are bent to form scoops facing into the air stream flowing through the outlet end of said tube to nozzle 1 8. The conduits 1 9 may be provided with valves operated manually and perhaps, by a governing device, automatically, controlling the supply of power fluid (compressed air) to nozzles 20 of air compressor 5 and thus the amount of air compressed by said air compressor and the thrust of the engine.

A means to preheat the water in jackets 3 and 4 and to start the engine's working cycle, comprises a single nozzle 22 adjacent nozzle 20 of the only or final stage of air compressor 5 and arranged to exhaust, during said phase, a jet of pressurized fuel vapour through the inlet of tube or chamber 1. The jet of fuel vapour also acts to induce an air flow through said inlet and the mixture is burnt in the divergent part of said tube or chamber, so heating jacket 3 from which steam would pass by pipe 12 into jacket 4 and heat the water therein. The air compressor nozzles 20 would receive some of the products of this combustion until said phase is complete.

Preferably, the fuel vapour supplied to nozzle 22 is obtained from a vaporizer placed in assembly 1 and heated by the combustion in its divergency, wherein said vaporizer desirably would be positioned.

To increase the thrust of the engine during for example, take off and climbing conditions, fuel, such as oil fuel vapour supplied to e.g. nozzle 22, is additionally burnt in the divergency of assembly 1.

To assist the conduction of heat from the steam led into jacket 2, to the cooled air expanding through the divergent portion of tube or chamber 1, external or/and internally disposed fins may be provided on the surface(s) of said tube or chamber portion.

Although the embodiment described is disclosed on apparatus whereby the working fluid feeding the venturi tube or chamber is compressed mainly by a jet type air compressor, it is obvious that an air compressor of some other kind, such as a turbine-driven unit, may be provided for said purpose or that said air compression may be effected exclusively by ram action or by combinations of these means.

A modification of the jet propulsion unit example now understood employs a heat transference means in which a fluid, such as air or water, is circulated by pump 7 through jackets 2, 3, 4 and the like and heat exchanger 13 or in which jacket 2 is connected to an air ejector 23 operated by the air jet from nozzle 1 8 and acting to draw ambient air, admitted by suitable vents to jackets 3 and 4 or only to jacket 4, through said jackets 3 and 4, heat exchanger 13 and finally jacket 2. Air ejector 23 is indicated in the top half only of the figure. A simple cowling replacing jackets 2, 3 and 4 optionally directs said ambient air over air compressor 5 and tube or chamber 1 to air ejector 23. Pump 7, which could be a fan in this case, could replace air ejector 23 as the means provided to induce the ambient air flow through jackets 2, 3 and 4 and heat exchanger 13 or even said cowling, which might be extended forward of the air inlets of air compressor 5 for example, to assist by the ram action of said air flow, the compression of the air feeding tube or chamber 1 or to exclusively effect this air compression; or said ambient air flow may be ram air.

A fourth system connects jacket 2 or the outlet of said cowling to the air inlet of air compressor 5 by a pipe not shown, to induce, by said compressor's suction, the ambient air flow through jackets 2, 3, 4, and heat exchanger 13 or said cowling, it being possible to deliver all or only a part of the engine's working fluid to said air compressor through said pipe.

Within reason, the power jet nozzles 20 of air compressor 5 can be supplied with compressed air obtained from another source, such as a turbine-driven auxiliary air compressor operated by the cooled or/and the reheated air stream(s) leaving said air compressor 5.

Because of the high efficiency of the heat transference means, the operating temperature of the venturi tube or chamber necessary to obtain effective continuous working of the apparatus without loss of power or thrust can be comparatively low, enabling a much lighter construction to be used with comparable engines having the same working fluid compression value and giving an enhanced reliability and freedom from fire risk.

Devices for improving the heat transference by the means disclosed may include fins placed on the surfaces of tube 1 and air compressor 5, corrugation of these surfaces and baffles for directing the heat conveying fluid stream systematically, for example up and down alternately or spirally, over them and superheating said fluid.

A second modification of the embodiment of the invention described with reference to the drawing, but utilizing ambient air for its heat conveyance, derives this fluid from the divergency of tube or chamber 1; said air being expanded through vents 24 into jacket 2, which functions as an additional cooler for the partially cooled compressed air, all of which passes into said jacket, delivered into said divergency by air compressor 5. The expanded air debouches from jacket 2 through suitable connecting pipes into jacket 3 and, if appropriate, jacket 4 and finally passes to utilization e.g. in a propulsion nozzle or a curved duct, indicated in the figure by the broken line 25, reversing the direction of its flow.

Said air is reheated in said jackets, and is returned by duct 25 into the air intake of air compressor 5, thus producing by this flow reversal, a reactive thrust on the fore wall of said duct. The heating coil 1 7 could be placed in duct 25, jackets 3 or 4 or in a cowling replacing jackets 2, 3, 4 and help to reheat said air. Alternatively, jacket 2 is omitted and the cooled compressed air from air compressor 5 passed directly or from vents 24, by a pipe or pipes, into jacket 3 for example, or said cowling. No extra energy is expended in displacing the heat conveying air, since this air is the working fluid of the engine and jackets 2, 3, 4 or said cowling form(s), at least partially, the divergency of tube or chamber 1. Only a portion of the working fluid is so utilized as the heat conveying medium, in another such arrangement.

In all embodiments of the invention employing a closed working fluid circuit, the recompression of the air feeding tube or chamber 1 optionally is induced by ram action due to the high velocity of the recycled air, but such engines described in the preceding paragraph may be provided with e.g.

rearranged jet type air compressors operated by some of their reheated working fluid led, by suitably modified conduits, to nozzle(s) 20 of said air compressors from the divergencies, such as jackets 2, 3 and 4 or a cowling duct replacing them or even the exhaust manifold of a turbine equipped installation, of their venturi tubes or chambers, for said purpose. The air compressor 5 is rearranged to be operated similarly by air from said jackets, cowling or manifold, in engines employing open working fluid circuits and functioning as disclosed in said preceding paragraph. Tubular heat exchangers, such as the unit 1 3, are preferred as the divergency of tube or chamber 1 and the source of the fluid directed to nozzle(s) 20, in some such embodiments.

The jackets 2, 3, 4 are connected either in series or separately to their fluid supply source.

Thermal insulation of all parts of the engine assemblies likely to incur a disadvantageous heat loss or gain is desirable. Conceivably, a small refrigerator or cryostat may be embodied to correct any such heat gain by a volatile heat conveying fluid.

Fuel, such as oil fuel or hydrogen, possibly in either liquid or vaporized form and derived from a vaporizer, such as jackets 2,3 and 4 or unit 13, may be injected into air ejector 23 and ignited and burnt therein, to increase the maximum thrust of the unit. Such fuel might also be burnt in an extension of tube 1 rearward of its heating jacket 2, for said purpose.

Power to drive ancilliaries, such as pump 7 or a dynamo supplying electric current to an electric motor driving said pump, is obtained from an embodied auxiliary power plant of any chosen kind or for example, a turbine or an air screw rotated by the engine's working fluid stream.

Several, such as a ring, of the units shown in the drawing may be united by suitable brackets to form a larger engine or/and feed an expansion device, such as a turbine or a single nozzle replacing the several nozzles 1 8 and the like.

The air compressors optionally replacing the jet unit 5, in effect, constitute or partially constitute the convergency of tube or chamber 1 and pass their hot cooling fluid to jacket 2, to effect the heat transference necessary in the engine's working cycle.

Referring again to the top half of the figure, when required, upon closure of a valve 26 in conduit 19, the nozzle 20 is supplied by a pipe 27 connected to said conduit on the downstream side of said valve, with its power fluid by an apparatus comprising an insulated vessel 28 in which a first fluid, such as water, is vaporized, a compressor 29 operating to compress a second fluid, such as ambient air, and deliver it through a clack 30 into said vessel for the purpose of heating said first fluid and possibly to replace any of this latter fluid lost by said vaporization, and a filter 31 for the said second fluid fed into the intake of said compressor.Comprising the full working cycle of this apparatus, some of the first fluid is furthermore, led by a pipe 32 from vessel 28 to an atomizer not shown, mixing said fluid with the second fluid also entrained by compressor 29, to cool this latter fluid during its compression and is returned with the second fluid into the lower end of said vessel, and a bypass with a stop valve 33 permits, to facilitate starting said cycle, this compressed mixture to pass directly to atmosphere during said starting process, but it should be understood that these provisions are not an essential requirement. The fluid mixture is fed into vessel 28 by a diffuser 34 consisting of a flat spiral tube coil connected at both its ends to the pipe delivering the said mixture and provided on its top side with multiple outlet nozzles submerged in the first fluid into which they discharge.

In the apparatus shown, the first fluid is liquid air and the compressor 29 is a jet type unit fed with ambient air and powered by some of the pressurized vapour (air) generated in vessel 28, which consists of two shells separated by a space from which the air is evacuated, and led to it by a pipe 35. Preferably, the vapour directed by pipe 27 into conduit 19 is superheated, for example by first using it to cool or help cool air compressors 5 and 29 or the air entrained by them, e.g. by passing it through heat exchangers incorporated in these units. A portion of the vapour or superheated vapour may be used to drive the auxiliary engine. The bypass 33 interposed between air compressor 29 and clack 30 is a desirable provision in this plant.

Relevant to the working cycle of the apparatus, the latent heat and first fluid lost by evaporation from vessel 28 is replaced by the condensation and the latent heat of this condensation of the compressed second fluid or mixture fed by air compressor 29 into said vessel. If this was not so, for example if the first fluid is water, a supply of said first fluid through a feed pump would be necessary to replace that lost from vessel 28 by said evaporation. Preheating of first fluids of low volatility, for example by electrical means, to raise steam when starting said working cycle, may be provided for. A small automatic cryostat may be embodied for the purpose of extracting surplus heat passed to vessel 28 from any other source, in the present installation.Inert first and second fluids, such as liquid and gaseous nitrogen or carbon-dioxide may be preferred for use in the closed circuit embodiments described. The vessel 28 may have an ordinary safety valve to release excess vapour. To obtain satisfactory working, operation of the vessel 28 above a critical minimum temperature at which the evaporation of the first fluid starts to exceed the increase in the applied heat is required. With water first fluid this temperature is roughly 2500 F.

An auxiliary power plant working according to this cycle could be arranged with either an open or a closed working fluid circuit, exhaust vapour recovery from the heat engine possibly being as mist carried in a different second fluid exhaust stream back to the compressor. A mixture of such a second fluid and the vaporized first fluid may be delivered to the heat engine of the plant.

Where the difference in the volatility of the two fluids used in vessel 28 is great or when a considerable difference in their operating temperature exists, little or no condensation of the second fluid fed into said vessel may occur and all or most of the heat passed by it to the first fluid may be sensible heat. It may be practical therefore to superheat the first fluid vapour by increasing said temperature difference. Also to regulate the heating of this fluid by passing second fluid through bypass 33 or control of compressor 29.

In a modification of the apparatus now described, condensation of the second fluid fed into vessel 28 is reduced or avoided by delivering it into said vessel at a point above the level 36 of the first fluid, the vapour of which is superheated by diffusion with said second fluid. Contrariwise, condensation of the vapour, which is vaporized first fluid mixed with the second fluid entrained by the compressor 29 in this case, in vessel 28, could be encouraged by withdrawing heat, by means, such as a small refrigerator, from the first fluid in said vessel, thus superheating said second fluid by transmission to it of the latent heat of said condensation. Heat removal from the first fluid might also be effected by circulating it by means, such as a pump or convection, through a radiator.

Waste heat from these first fluid cooling devices could be used to superheat the second fluid or/and vapour leaving vessel 28, in these and in the other embodiments of the apparatus.

The location of superheating heat exchange systems between compressor 29 and vessel 28 is practical, as is cooling of the second fluid entrained and compressed by compressor 29 and this compressor itself, by first fluid fed heat exchangers employing convection, gravity or a pumped supply circulating means for this first fluid, which is derived either from vessel 28 or from a cold feed supply or the like. Vaporizing such first fluid fed cooling methods pass their vapour into vessel 28 or to the superheater helping to cool compressor 29 or/and the second fluid. The use of combinations of the compressor and second fluid cooling methods described and including the mixing of cold feed first fluid with said second fluid, where appropriate, is practicable and may be advantageous. Vessel 28 may even be formed by the first fluid fed heat exchange system.

It is assumed that in the apparatus shown the temperature of the first fluid in vessel 28 may have to be regulated, for example by control of the heat withdrawal from the second fluid for superheating purposes, to prevent loss of said first fluid by excessive evaporation, from said vessel.

The air compressed by air compressor 5 may be cooled to liquefaction and then reheated to a gaseous state in the divergency of tube cum chamber 1 or the part of said divergency used for reheating purposes, by employing liquid air coolant in for example, jackets 3 and 4 and heat exchanger 13, which may form said divergency or part of it.

The liquid air leaving e.g. air compressor 5, is preferably sprayed under its own pressure into the divergency or the part of it devoted to reheating said air, or tube 1, by a ring or rings of small nozzles or atomizers, perhaps directing it onto the hot surfaces of said divergencies.

Some of the liquid coolant may be bled, from jackets 3, 4 and assembly 1 3 for example, and sprayed directly into the air ducts of air compressor 5, to enhance the heat transference from and back to the working fluid, for power generation. Such coolant may need to be pump pressurized for feeding purposes or may use its own pressure to effect its supply.

Liquefaction of the working fluid may of course be carried out with the use of any coolant medium and other kinds of compressors and compression systems, such as those I have referred to in this description previously.

Allowance for the increased electrical resistance, caused by its heating, of the oscillatory circuit 1 5 would be necessary in the design of this circuit, which is not confined to the simple arrangement shown.

The fluid delivery pressure obtainable with injectors or jet type compressors depends largely upon the density of the pumped fluid, and cooling the air compressed by air compressor 5 increases the density of said air; it is advantageous therefore, to supply nozzle(s) 20 with some of-the cooled compressed air leaving said air compressor, thus increasing the cooling and the density of the air under compression in this air compressor. The nozzle 20 of the first compression stage of the two stage air compressor 5 shown in the lower half of the drawing might, in this way, be supplied with some of the cooled compressed air debouching from air duct 21. Irrespective of the cooling of the air under compression by the cooled air issuing from nozzle(s) 20, the average density of the mixture of these two fluids is increased merely due to the greater density of the latter air.

Another means for increasing the average density of the fluid under compression in air compressor 5 comprises the mixing of a heavy fluid, such as water or liquid air, with the air entrained by said air compressor and perhaps an arrangement for the recovery and recycling of said fluid after its initial use. The necessary equipment for mixing the heavy fluid with the entrained air could consist of one or more suitably positioned spray nozzles fed with said heavy fluid and discharging it in a downstream direction, into the entrained air stream. The division of the heavy fluid by the spray nozzles with suitable design of these nozzles is reduced to a level which would prevent atomization and the-vaporization of said fluid in the air compressor and consequent loss of density by this fluid. A provision to cool any recycled heavy fluid may be required also, to prevent its vaporization.

A new non-thermal process for power generation is involved consisting of the compression of a primary fluid, such as air, at a pressure determined partially by the average density of said primary fluid and a heavy secondary fluid mixed with it, by a jet type compressor operated by some of said compressed primary fluid, mixing said heavy secondary fluid with the primary fluid entrained by said compressor, to increase the delivery pressure of said fluid mixture, optionally the recovery, cooling and recycling of said secondary fluid from said compressed mixture, and the utilization and expansion of said compressed mixture or the remaining compressed primary fluid or both these media, in a device or devices, such as a nozzle or/and a turbine, or/and the transfer of heat from said fluids.

The air compressors alternatively supplying compressed air to tube cum chamber 1 or to its divergency, are either displacement or impulse units or even a multistage jet type air compressor or the apparatus shown in the top half of the drawing and supplying compressed air only to nozzle 20, or a similar apparatus employing the power generation cycle or process defined in the preceding paragraph.

A refinement of the embodiment shown in the drawing includes the use of the air ejector 23 as an extension of the divergency of tube or chamber 1, acting to reheat or help reheat the cooled compressed air debouching from air compressor 5 mixed with the ambient air drawn into said ejector. To this end, air ejector 23 could for example, incorporate a heating jacket fed with the or some of the steam generated in jackets 3, 4 and unit 1 3 or entrain exclusively or in combination with its entrainment of ambient air, the hot cooling air from air compressor 5, which might then be operated by some of the ejected mixture. This heating device alternatively is supplied with hot vapour and air mixture led from vessel 28 or from a superheater fed with said mixture, in an appropriate example, or even acts as said vessel or a separate cooler for its first fluid.The use of similar heating devices to supplement the heating of the cold air fed into the main divergency or its other extension not being said air ejector, disclosed, of venturi tube cum chamber 1, is also anticipated.

The apparatus using vessel 28 employs a process for producing energy consisting in the compression of a primary fluid, such as air, the utilization of said compressed primary fluid to heat and vaporize a secondary fluid, for example water, and the expansion of the vapour so generated or a mixture of it and said primary fluid, in a devices, such as a nozzle or/and a turbine, or/and the condensation of said vapour or fluid mixture and heat transference from said secondary fluid in a heat exchanger.

Heating devices fed with hot air and vapour mixture by vessel 28 or by its superheater could condense said vapour to a liquid state and return this liquid by gravity or by a pump, back into said vessel, the remaining cooled air being expanded in a device, such as nozzle(s) 20 or a turbine.

Other heating devices receive only hot compressed air from vessel 28, the cooled air leaving them being expanded similarly.

The duct 25 in the lower half of the figure might advantageously terminate in a nozzle or nozzles coaxial with air duct 21 through which said nozzle(s) would exhaust, or be connected to said air duct thus, in the appropriate examples, by the momentum of the reheated air working fluid debouching through said nozzle(s) or duct 25, recompressing said reheated air.

The power fluid supplied to nozzles 20 may possibly be steam, preferably obtained from an electrically heated boiler, which could be of any convenient design, or for instance, jackets 3 and 4 and heat exchanger 13 or a multitubular or coiled tube boiler incorporated in said jackets and heated by their heat conveying fluid, and replacing said heat exchanger.

Appertaining to the invention, the transfer of a portion of the heat of the heat conveying fluid of installations, by diverting some of said hot fluid or its vapour through a suitable heat exchanger, for use in a lesser process, such as aircraft cabin heating, is concurrently envisaged.

It may be convenient to drive the ancilliaries, for example pump 7, by electrical means in lieu of any other method, electrical power supply means comprising a thermionic valve alternator supplied with its operating low and high voltage electric current by its own circuit through a rectifier and transformer arrangement, being viewed for energising said driving means.

The overall length of the example described with reference to the drawings could be shortened by positioning the divergent portion of tube or chamber 1 , its heating means 2 or the like, and for instance nozzle 18, alongside air compressor 5, which could direct its compressed air through a bent connecting pipe to said portion of tube 1, thus compacting the assembly. Or said divergency of tube or chamber 1 could be connected to and exhaust its reheated fluid through duct 25, or the entraining tube 37 of air compressor 5 may form and function as said divergency in addition to its normal use and be heated by said heating means and receive the cooled compressed air leaving the high pressure delivery side of said air compressor through a suitable pipe connection.These latter units and those previously disclosed directing their reheated working fluid through air duct 25 constitute -closed system jet propulsion units wherein a means is provided to collect their propulsion jet fluid after its expansion through e.g. said air duct, to produce a thrust reaction, and to continuously recompress said fluid and cool it to reduce its velocity, momentum and volume and therefore its counter thrust, in air compressor 5, so recuperating said fluid whilst maintaining a positive forward thrust.

The invention moreover also concerns jet propulsion unit installations of the closed system kind described in the preceding paragraph, but in which the reheated air expanded through nozzle 18 is collected in a recompression chamber placed downstream of said nozzle and cooled by a heat exchange means, such as water jacket coupled to the engine's heat transference system and incorporated in said chamber, and equipped with an inlet nozzle for the entry of said air and, at its opposite end, with an outlet connected by a return pipe or channel to duct 25, power nozzles 20 or/and to the low pressure air entraining tube 37 of air compressor 5, and in which chamber said air is recompressed, by the conversion of most of its momentum into pressure, and its compression heat lost to said heat exchange means and finally directed- through its outlet to said return pipe or channel, which conveys it back to said air compressor. To exclude the ambient air from the recompression chamber, in such examples, nozzle 1 8 is connected to said inlet nozzle by a small vacuum chamber. The heat lost from the recompressed air is recuperated in the unit's heat transference system. The air pressure in the recompression chamber is reduced by this heat loss.

Closed system units employ any chosen or convenient working fluid, although the medium used in most of the embodiments described is air, since said fluid circulates continuously in its closed circuit.

The fuel vapour nozzle 22 might be designed as a compound unit mixing extra liquid fuel with the fuel vapour jet issuing from said nozzle, which could function as an ejector and a vaporizer for said liquid fuel. To the latter end, the fuel vapour fed to nozzle 22 is highly superheated and the volatility of the liquid fuel is increased by preheating it before its delivery to said nozzle.

Metal fuels, such as liquid sodium, potassium calcium or magnesium, with appropriate e.g.

water injection provision or combined said metal fuel and oil fuel, for example in emulsion, colloidal solution or separate feed form, perhaps without said water supply provision, can alternatively be utilized.

Preferably, the compression and cooling chamber of the closed circuit jet propulsion unit embodiments would employ its compressed cooled working fluid stream, expanded through vents, such as vents 24, into its cooling means, to cool its compresed working fluid, albeit any other of the heat transfer methods described can be employed for said purpose, exclusively or in combined systems. The density of the working fluid fed into said chamber would also be increased by methods similar to those optionally employed by air compressor 5, to increase the compression of said fluid obtainable therein, rendering the use of a smaller such chamber practical.

The invention does not obviate the use of a metal, such as sodium, potassium, calcium or even magnesium, as the heat transferring medium, but a means, such as a thermostat controlled electric heater, may be an essential provision to maintain the fluidity of said medium in such design.

A gas generator unit according to this invention supplies compressed air to compressor nozzles 20, in a final embodiment, as an auxiliary inclusion, although an auxiliary such unit of any other chosen kind could be embodied to supply the said air.

In a possible modification of the liquid air driven plant shown in the top half of the figure, an ordinary injector operating to feed ambient air, which would become liquid in the process, and very cold liquid air drawn continuously from the bottom of vessel 28 into said vessel, replaces air compressor 29 and said vessel is cooled by the air led to nozzle 20 by pipe 27.

Nitrogen could be boiled off from a liquid air heat conveying fluid and, with precise temperature control, the liquid oxygen left, drawn off for utilization, thus adapting embodiments to function as liquid oxygen producers. Priming of the heat transference means with liquid air before starting this process is desirable. The nitrogen vapour given off could e.g. be fed to an expander, or be exhausted to atmosphere or used as a coolant.

To facilitate starting the working cycle of the example illustrated and improve its low thrust operating characteristics a means for bleeding some of the expanding working fluid from tube cum chamber 1, when required, and passing said fluid to atmosphere or back to the air inlet of its jet compressor 5 via suitable channel connections, may be provided. Such a provision may, for example, be necessary in a water borne vessel jet propulsion application with underwater fluid jet discharge, owing to the back pressure of the water affecting the expansion of the working fluid through nozzle 18 or through water ejector(s), whuch may also comprise the equipment, operated by said working fluid. That is to say, to keep the unit functioning as a hot tube or chamber engine at reduced working pressure.

High pressure working fluid to operate the jet compressor 5 may be led from any available source. Cooling water or steam mixed with or, in the latter case, forming said fluid, could also be utilized to oxidise the metal fuels referred to previously. The co-combustion of hydrocarbon fuel in tube 1 would generate such mixed steam oxidant.

The liquid air driven plant disclosed for use as the compressed air supplier for the power nozzles 20 of air compressor 5 is a heat engine in accord with my co-pending patent application No.

81 32375 of the United Kingdom.

The duct 25 in the lower half of the drawing, may incorporate curved guide vanes for the purpose of reducing the energy loss from the working fluid conveyed through it, by shock.

Vapour working fluids may be cooled at least partially to a liquid state, such as mist form, in closed system plants, liquid condensate being reused by diffusion in the remaining vapour or by spraying into compressor coolers.

Claims (14)

Claims

1. A hot venturi tube or hot chamber thermal engine comprising one or more venturi tubes or chambers receiving a working fluid, such as air, at a pressure sufficiently high to increase substantially its temperature and employing a thermodynamic cycle in which useful power is produced by a process of heat transference from the working fluid under compression feeding said venturi tube(s) or chamber(s), back to this same fluid upon its expansion through their divergent section(s), is characterised by the fact that, in said process, a part at least of the heat transference is effected by a comparatively light heat conveying fluid, such as air or water, circulated by for example, a mechanical pump, through a heat exchange device or devices constituting, with said heat conveying fluid and its displacement provision, the means for said partial heat transference for power production.

2. The thermal engine defined by claim 1, comprising open circuit or closed circuit working fluid channels, in a closed circuit such engine, the working fluid return portion of said channels being or not being the divergent section or sections of its venturi tube(s) or chamber(s) and, in the appropriate instance, incorporating the working fluid reheating means, or only being a part of said divergent section(s), said channels also having a provision, such as a turbine, a propulsion nozzle or a curved thrust reaction producing bend, for the expansion of said working fluid for remote utilization, in a preferred construction the placing of said divergent channel section(s) alongside said engine's working fluid compressor, appropriate examples further providing branch working fluid channel(s) for the carriage of motive fluid to the power nozzle(s) of jet such compressors, air ejector devices and means to burn fuel in said working fluid or to heat this fluid electrically.

3. The thermal engine in claim 2, comprising open circuit or closed circuit heat conveying fluid channels, in the latter such channels a provision to release air therefrom upon vapour formation therein from a liquid heat conveying fluid and admit ambient air into said channels upon the cessation of such vapour formation therein, and a provision to release excess such vapour from said channels, alternatively, the arrangement of said channels to convey exclusively gaseous or liquid fluids, multiple said channels being connected either in series or in parallel, said gaseous fluid conveying channels in a specific example, being combined with said engine's working fluid channels.

4. The thermal engine in claim 3, comprising heat transference means consisting of a circulating gaseous, liquid or liquid and gaseous medium, optionally with a provision to regulate the flow of said media for the purpose of controlling the power output or thrust reaction of the engine, in said means.Further, the optional employment in continuous operation of preheating and superheating methods for said medial, and the diffusion of liquid said media in the working fluid of the engine, additionally vaporizing and condensing methods with said liquid or liquid and gaseous media, a vaporizing liquid said medium being preheated, if of low volatility, prior to starting the engine's working cycle, by combustion gas or electrical heating methods, to induce said fluid vaporizing, said continuous media preheating and superheating being effected by transferred compressor heat or, in the latter instance, similarly.

5. The means in claim 4, comprising the reheating of the expanding working fluid by the diffusion therein of heat conveyance fluid vapour, in a specific instance, by the utilization of said vapour also to effect or partially effect the working fluid compression in a jet type compressor, or by the diffusion in said fluid of hot heat conveyance air, in an air ejector.

6. The means in claim 4, comprising a circulating liquid fuel and its vapour.

7. The means in claim 4, comprising the circulating working fluid or a portion thereof, in liquid or/and gaseous form, in a specific instance, with a provision for the continuous separation of nitrogen from a liquid air said fluid and the withdrawal of the liquid oxygen remainder.

8. The thermal engine defined by any previous claim, comprising heat conveyance fluid pumping or displacement means of either mechanical or/and fluid jet operated kind, ram action inducement or the relative wind, said jet operated means being either said engine's working fluid compressor, its air ejector or an auxiliary such unit, said mechanical means being auxiliary units or even said engine's working fluid compression system, inclusive of heat conveyance fluid vapour operated auxiliary mechanical or jet such methods usage and the utilization of fluid suction or/and pressure modes of actuation.

9. The thermal engine in any previous claim, comprising heat conveyance fluid channels also constituting the divergencies of its venturi tubes or chambers or portions of said divergencies.

10. The thermal engine in any previous claim, comprising heat conveyance fluid channel means extending to cover working fluid compressor intake ducts, compression nozzles and connecting tubes, working fluid operated air ejectors or even working fluid jet recompression, cooling and recovery chambers.

11. The thermal engine in any previous claim, comprising heat conveyance fluid channels consisting of jacket, coiled tube or multitubular heat exchangers or combinations of such assemblies, such as a liquid fed coiled tube immersed in and heated by the liquid coolant contained in a jacket and generating high pressure steam for use as the motive fluid of jet type air compressors supplying working fluid to said engine, or merely simple combined systems, a plain cowling or including such a cowling, said channels optionally employing corrugated or fin surfaces and fluid directing baffles to enhance their heat transferring capabilities.

12. The thermal engine in any previous claim, comprising electronic heat transference means acting to generate electrical energy from the hot working fluid under compression, thus cooling said fluid, and utilize said energy to reheat said cooled working fluid during its expansion.

13. The means in previous claim 12, comprising a high frequency oscillator energising a resistance or an induction electric heater or a plasma producing device or a thermocouple and a such heater or device.

14. Ajet propulsion unit substantially as hereinbefore described with reference to the foregoing claims and the drawings, comprising means to collect for re-use the working medium it employs to produce a reactive thrust consisting of either the return portion of its closed working fluid circuit or a compression and cooling chamber system receiving said medium prior to its return to and re-entrainment by said unit's compressor and connected by its inlet nozzles and an interposed vacuum chamber arrangement to the unit's propulsion nozzle and provided with a heat exchanger coupled to said unit's heat transference means, and, at its outlet end, with a pipe or channel connection to the inlet of said compressor, for the cooled medium, a positive thrust being obtained respectively, by reversing the direction of flow of the working medium stream returning, after its reheating therein, through said closed circuit portion, and by reducing the counter thrust, by cooling it in said compression chamber(s), exerted by said medium, preferably said medium, in this latter instance, being cooled during its compression by itself through expansion, after said heat withdrawal, into said heat exchanger and by the diffusion in said medium of liquid coolant or by any other of the heat transference methods disclosed, provision optionally being made to increase the density of said medium, to raise said compression.

1 5. In the thermal engine definite by any previous claim, working fluid compression means consisting of an auxiliary plant, such as an electrically heated steam boiler, the regenerative cycle air compressor described with reference to the top half of the drawing or a turbine driven auxiliary air compressor, acting to supply power fluid to a jet type (main) working fluid compressor, a turbine driven impulse or displacement such compressor or a working fluid or air ejector mixture operated jet type unit, ram air or fluid momentum actuated systems, for example air ejector induced flow and exhaust fluid momentum methods, a provision to mix a heavier fluid, such as water, liquid or cooled air, with the working fluid under compression in a jet compressor, to increase said working fluid's average density and thereby the compression obtained, or superheating of the power fluid of such a jet compressor by heat derived from the engine's heat transference fluid, and auxiliary gas.

generator unit equipment for supplying said power fluid.

1 6. A hot venturi tube or hot chamber thermal engine designed, constructed or operating substantially as hereinbefore described with reference to the two halves of the accompanying drawings.