ITNA20100049A1 - SINGLE-OPERATIONAL STIRLING MACHINE - Google Patents

Description

DESCRIPTION

Of the invention entitled "ONE-WAY FLOW STIRLING MACHINE"

DESCRIPTION

TECHNICAL FIELD

1. The present invention relates to the field of machines based on the Stirling cycle. It can be motors, capable of extracting a certain amount of mechanical work from thermal energy, to be used in various ways, or it can be chillers or cryogenerators which, operating in reverse cycle with respect to the motors, exploit the mechanical work applied to subtract heat aN environment and generate low temperatures. The present invention is a closed cycle machine, like the usual Stirling machines, and, in particular, it has an advantageous and innovative construction architecture which increases its efficiency and specific power.

PRE-EXISTING ART

2. The classic problem of Stirling cycle engines is that of the coordination difficulties between thermodynamics and mechanics. In fact, the thermodynamic transformations imposed by the cycle provide for speed variations, due respectively to the absorption of heat and the transfer of heat, which lead the pistons to follow a somewhat discontinuous motion. However, the moment of acceleration of the piston of the expansion chamber does not coincide at all with the moment of acceleration of the piston (displacer) of the compression chamber. Connecting the motion of the two pistons in a uniform motion, useful for immediately activating an alternator, is not easy. In this way, compromise solutions have been reached, which however strongly penalize the performance of the machine. This happens because by imposing - starting from the rotation axis - the motion to the pistons, this is quite distant from the thermodynamics requirements of the Stirling cycle.

3. Attempts have been made to respond to these difficulties in various ways. An answer, which was remarkably successful, was offered by the innovation proposed by W. Beale in the second half of the last century, with the introduction of the so-called Stirling engine "Free piston". The Free Piston engine is characterized by the absence of crank mechanisms and by the fact that it is the same sequence of thermodynamic transformations that determine the movement of the piston and the displacer, whose motion is precisely determined by the so-called pressure waves, certainly with a good improvement in mechanical performance, even if the system is of complex design, it requires the use of linear electric generators, and in any case perfect thermal insulation between the hot and cold parts is difficult.

4. In the state of the art it is possible to find some examples on the subject of innovative kinematics. Eg. see US patent 5644917, in which the use of cam wheels with movable pins is proposed which overall make the real cycle very similar to the theoretical one. However, for this mechanism, the absorption of mechanical energy is truly remarkable

5. The recent patent application of the same inventors (Scala-Riccelli-Gargano, Italian filing prot. NA2010000043) combines the high mechanical performance of the Free Piston with the simplicity of configurations with crank mechanism; the current invention is a further advance towards constructive simplicity and the achievement of higher powers.

EXHIBITION OF THE INVENTION

6. The ideal Stirling cycle is characterized by the thermodynamic transformations of a quantity of fluid which - as a result of the absorption and transfer of heat - undergoes non-symmetrical thermal and volumetric variations. The asymmetry of the volumetric variations results in an asymmetry of the motion of the pistons moved by the fluid.

It is possible to correct this asymmetry by providing as many distinct volumes (chambers) traveled by the fluid, as are the phases completed by the same fluid during the ideal Stirling cycle.

Since the ideal Stirling cycle is divided into four phases (in each phase the volume of the fluid has a monotonous trend and therefore the relative movements of the pistons are simplified) there are four chambers, not all equal in volume, in which the fluid performs, passing in sequence from one chamber to another, the thermodynamic-volumetric transformations typical of the cycle itself.

The fluid assumes, from time to time, the volumetric values of the chambers. The pistons therefore have a symmetrical and uniform motion.

The system, therefore, is schematically divided into:

- four chambers, two in a warm environment (the first with a smaller volume than the second) and two in a cold environment (the first with a larger volume than the second), each communicating with the adjacent ones;

- system of lights or valves (according to the use of rotary or alternative pistons), loading and unloading systems for each chamber;

- system of exchangers, so that the flows of fluid coming from the hot and cold side, crossing each other, exchange heat; auxiliary exchangers are provided between the two high-temperature chambers, as well as between the two low-temperature chambers, in order to optimize the heat exchange with the external environment.

working fluid circulating inside the chambers, which enters the smaller hot chamber, absorbs heat and expands assuming the volume of the larger hot chamber, then passes to the larger cold chamber through the exchanger, and then releases heat and compresses assuming the volume of the minor cold room; from here, finally, the fluid passes through said exchanger to return to the smaller hot chamber. The piston of the larger hot runner and, to a lesser extent, that of the smaller hot runner, take out mechanical work.

The compression and expansion chambers can be of a fixed structure (classic chambers with alternative pistons), or of a mobile structure, created by the geometry and reciprocal motion of the stator and rotor device (s), such as, for example, in the case of bladed rotors.

The description of the machine is made starting from the alternative piston variant, as it is easier and more immediate to understand. The variant with rotary pistons will be illustrated below, in a succinct manner, being able to refer to the construction principles learned in the analysis of the machine with alternative pistons.

It is evident that, regardless of the implementation solutions adopted, the inventive idea is summarized in the independent claim, number 1, formulated as follows:

1) Stirling cycle thermal machine, suitable for driving or operating function,

comprising:

- at least two thermally insulated environments (1, 2), even at different temperatures;

- at least one compressor machine, suitable for being located in one of the aforementioned environments and built with at least partly thermally conductive materials, so as to exchange heat with the working fluid and with the environment in which it is located;

- at least one expanding machine, suitable for being located in one of the aforementioned environments and built with materials at least in part thermally conductive, so as to exchange heat with the working fluid and with the environment in which it is located;

- at least one heat exchanger, suitable for allowing the exchange of heat between the working fluid flows, having different temperatures, coming, respectively, from the compressor machine and from the expander machine;

- working fluid, suitable for running - cyclically and with a unidirectional flow - a circuit, through compressor, exchanger and expander; the fluid being suitable for exchanging thermal energy, even with the environments containing the machines, in the said path between the compressor, exchanger and expander; said latter devices being able to cooperate to induce the working fluid to perform basically isothermal thermodynamic transformations, in the circulation through the compressor machine (isothermal compression) and through the expanding machine (isothermal expansion); and to perform regenerative transformations which tend to be isochore in the transfer, through the exchanger, from one machine to another; thus carrying out the Stirling cycle, direct or reverse. The elements that make up the machine are now examined in detail and individually, warning the reader that the description focuses on the direct Stirling cycle.

ROOMS:

7. The proposed technical solution is explained, as mentioned, in independent claim number 1. The elementary configuration of the machine provides four chambers (volumes), each associated with one of the four typical phases of the Stirling cycle (isochoric transfer from the cold side to the heat, isothermal expansion, isochoric transfer from the hot side to the cold side and, finally, isothermal compression). In each of these four chambers only one of the four transformations of the Stirling cycle takes place. Precisely, isochoric transfer takes place in the first chamber (hot side); in the second chamber (hot side) the actual isothermal expansion takes place; in the third chamber (first cold side) isochoric transfer takes place; in the fourth chamber (second cold side) the actual compression takes place. The entire cycle is then completed with the passage of the working fluid from one chamber to another. Unlike the classic configurations of Stirling engines (Alfa, Beta and Gamma), in which a single hot volume and a single cold volume can - in principle - be distinguished and in which the engine works with the cyclic flow of fluid from the "hot chamber" "(Expansion) to" cold (compression), in the machine of the present invention the expansion chamber and the compression chamber are distinct, each of them in chambers of different volume, and the entire cycle is carried out through the circulation of the fluid in a "circuit" represented by the four (or more) chambers.

8. Wanting to summarize the principle effectively, it can be said that the fluid moves with harmonic linear motion in the classic Stirling configurations (from the compression chamber to the expansion chamber, from the expansion chamber to the compression chamber and so on), while in the present configuration they move with a uniform circular motion (from the first chamber to the second, then to the third, to the fourth, and again from the fourth to the first and so on), crossing environments (i.e. chambers) placed at different temperatures and characterized by volumes are not all the same. Precisely, the volumes are different to correspond to the expansion phase (in which the volume of the fluid tends to increase) and to the compression phase (in which the volume of the fluid tends to decrease). 9. Therefore, the heart of the inventive idea is to circulate the working fluid, in sequence, from the first expansion chamber, to the second, and then to the first and second compression chamber, so that the volume variations determined by the Thermodynamic transformations of the Stirling cycle carried out do not translate into an accelerated motion of the pistons, which is difficult to synchronize, but are in accord with the volumes of the chambers in which the fluid circulates, corresponding to the volume variations assumed by the gas during the cycle. Consequently, the second compression chamber will have a volume equivalent to that of the first expansion chamber (because the passage of the fluid corresponds to the isochoric transfer phase); the first expansion chamber will have a smaller volume than the second expansion chamber (because the passage of the fluid corresponds to the isothermal expansion phase); the second expansion chamber will have a volume equivalent to that of the first compression chamber (because the passage of the fluid corresponds to an isochorous transfer); the first compression chamber will have a greater volume than the second compression chamber (because the passage of the fluid corresponds to an isothermal compression). In summary, the volumes cited relate as follows:

Espi <Exp 2 = Comp 1> Comp 2 = Exp 1

10. Thus, the system is divided into at least four chambers, at least two for expansion and at least two for compression, in which the volumes are differentiated by tracing (in principle) precisely the volumes depicted in the didactic representations of the Stirling cycle (for all, see the text Heat and Thermodynamics, by M. Zemansky, published in Italy by Zanichelli, Bologna). The didactic representations indicate the cycle consisting of four transformations, in which the fluid occupies, in sequence, half a warm volume, a hot volume, a cold volume, a cold half volume, and then starts the cycle again with a warm half volume. The result of this elementary graphic schematization is expressed in the PV diagrams usually used to demonstrate the theoretical efficiency of the cycle. Therefore, as in the schematizations, the proposed machine will have four chambers, two for expansion and two for compression, the first of volume 1⁄2 X (hot half volume), the second of volume 1 (whole hot volume), the third of volume 1 (cold whole volume) and the fourth volume 1⁄2 X (cold half volume). It is obvious that the provision of a 1 to 2 ratio between the volumes of the chambers is the result of a theoretical schematization, other volumetric ratios being possible, depending on the operating conditions of the machine (temperature and pressure). The fluid will circulate, absorbing heat in the first two chambers and releasing heat in the other two. The circulation of the fluid is ensured by the presence of pistons in the chambers, each out of phase by 180 degrees with respect to those of the adjacent chambers in the completion of the cycle (i.e. the previous and the next) so that when a piston rises pushing the fluid the immediately following one descends letting in the fluid, and so on for all four chambers considered. This occurs in the alternative piston configuration; in the variant with rotary pistons, the timing takes place, as is obvious, differently.

11. It will not escape the observer that the machine performs two overlapping cycles at the same time. In fact, when the working fluid is in the compression phase, symmetrically, another portion of fluid is already carrying out the expansion phase. This feature explains how it is possible - at the same time - to coexist two isochoric transfers, one in one direction (from the hot side to the cold side) and the second in the other direction (from the cold side to the hot side). And it is precisely for this peculiarity that an exchanger can be used in place of the classic regenerator, with the advantages described below.

THE EXCHANGERS

12. Traditional Stirling machines use a device, called a regenerator, to improve the performance of the system. The regenerator consists of metal wool, or another element with a high thermal storage capacity, which works by absorbing heat from the fluid that passes from the hot side to the cold side, and then retains said heat and gives it back to the working fluid when this is pushed from the cold side to the warm side. In the machine according to the present invention, since the working fluid makes a "circular" path, a certain quantity of cooled fluid is simultaneously transferred to the first expansion chamber, while another quantity of hot fluid is transferred to the first chamber compression. The two isochoric transfers mentioned take place in separate ducts, this being possible precisely because the working fluid follows a circular and non-linear path (forward / backward). Therefore, for these two reasons (contemporaneity of isochoric transfers and circularity of the fluid path) it is possible to use an exchanger instead of the classic regenerator. The benefits are significant. The need for thermal accumulation, typical of the regenerator, is eliminated, because the circulation of the hot portion of the fluid and of the cold one occurs at the same time and in opposite directions, ideal conditions for reaching the maximum efficiency of the exchanger. Since the regenerator is no longer there, there are no more friction losses deriving from the passage of the fluid through the metal wool or in any case through the porous material.

13. In addition to the "main" exchanger, operating in the isochoric transfer phase between the hot fluid and the cold fluid, auxiliary exchangers are provided in the connection ducts between the first and second expansion chambers and the first and second compression chambers . The role of the auxiliary exchangers is to maximize the efficiency of the heat transfer (therefore, ultimately, of the heat exchange with the external environment) in correspondence with the isothermal transformations, i.e., respectively, of the isothermal expansion phase and of the compression isotherm. Consequently, when the fluid, already heated, passes from the first expansion chamber to the second expansion chamber, it passes through the connection duct, which also acts as an exchanger with the external hot environment and, significantly taking advantage of the turbulence created, absorbs heat and pushes the piston down, allowing the latter to extract mechanical work from the cycle. Symmetrically, the auxiliary exchanger located between the first and second compression chamber facilitates the removal of heat from the working fluid, facilitating the compression phase. The cycle is thus completed, which then begins again with the passage of the fluid from the second compression chamber to the first expansion chamber.

14. The presence of auxiliary exchangers, which also act as a connection between the first and second expansion chambers as well as between the first and second compression chambers, is of considerable advantage. These exchangers, in fact, help to generate turbulence in the motion of the working fluid. The turbulent motion allows a significant improvement in the transfer of heat from the external environment to the said working fluid. All this with a good improvement in system performance, also in terms of obtainable power, due to the greater usable displacement.

VALVES (alternative piston variant)

15. To allow the fluid to circulate as programmed, valves are provided, placed on each chamber, in order to regulate the flow of the working fluid. Precisely, each chamber has two valves, one for the intake (or load) and one for the expulsion (or exhaust). In each chamber, the filling valve will open in correspondence with the downward phase of the piston, and will close in correspondence with the rising (thrust) phase of the same piston. Conversely, and symmetrically, the exhaust valve will remain closed during the descent phase of the piston and will open during the ascent phase. This synchronism allows the working fluid to pass from one chamber to another, in correspondence with the movement of the pistons. The valves can be controlled by common camshafts, suitably designed and manufactured, in order to keep the valve closed at one half turn of the crankshaft, and to keep the valve open at the other half turn. In the rotary piston variant there are no valves properly so called, but loading and unloading ports, whose opening and closing is determined by the motion of the rotors (rotary pistons) inside the stators.

16. In an alternative double-acting machine, the valve distribution system may be borrowed from those used, for example, in alternative steam machines (slide valves or equivalent).

SYNCHRONISM (alternative piston variant)

17. The valve system and the movements of the pistons are obviously synchronized to determine the circulation of the working fluid from one chamber to another. Of particular importance is the timing of the pistons. They must be placed in such a way that each is in phase opposition with that of the immediately preceding chamber in the direction of circulation of the fluid, and, likewise, must be in phase opposition with that of the immediately following chamber in the direction of circulation of the fluid. fluid. Therefore, when any chamber is expelling fluid, and therefore the piston is evidently in the upward phase, running up to the TDC (top dead center), the immediately following chamber has the piston in the descending phase, which runs towards the BDC (bottom dead center). ) and ultimately sucks in the fluid coming from the thrust from the other chamber. On the other hand, when a chamber sucks in fluid, the piston of the immediately preceding chamber, being in phase opposition, pushes it inside. The transfer of fluids occurs by virtue of the opening and closing of the valves, properly controlled, as explained in the previous paragraph and as illustrated in the table below. The schematic of the operation of the machine is quite simple:

Operating table (Alternative piston variant)

DETAILED DESCRIPTION / BEST WAY OF IMPLEMENTING THE INVENTION

18. The simplest construction variant is that with reciprocating pistons and controlled valves. The machine can be described, in its elementary configuration, as a four-chamber system, consisting of the following components: a) a first expansion chamber; b) a second expansion chamber; c) a first compression chamber; d) a second compression chamber; e) four pistons which slide in each of the four chambers and transmit motion to a common drive shaft for all four chambers; f) system of valves, placed on each chamber, controlled by a camshaft, even if other solutions are possible; g) heat exchanger system;

19.11 valve system allows the working fluid to circulate in the four chambers, sequentially, and precisely in the first expansion chamber, then in the second expansion chamber, then, passing through the auxiliary exchanger, in the first compression chamber and then in the second compression chamber, to then return, again passing through the auxiliary exchanger, to the first expansion chamber. Each chamber is therefore equipped with two on / off valves, i.e. only open or only closed, of which the first is a suction valve, as it opens when the working fluid is pushed - by the piston of the previous chamber - inside, until the piston stroke has come to an end. Then, the intake valve closes and, simultaneously with the inversion of the piston stroke which begins to rise, the other expulsion valve opens to allow the working fluid to exit the chamber, pushed by the piston, and to continue your journey by entering the next room.

20.1 pistons are suitably out of phase with each other in such a way that, when one of them descends, those relative to the adjacent chambers rise, defining the other two chambers crossed previously and subsequently in circulation as adjacent to a chamber. In this way, the combined action of the pistons and valves allows the working fluid to pass through the four chambers, in sequence, making the thermodynamic transformations required by the Stirling cycle. This can happen because the expansion chambers are placed in contact with a heat source, while the compression chambers are located in contact with a cold source.

21. The exact completion of the Stirling cycle is determined by the presence of the heat exchanger system. When the cooled working fluid is in the second compression chamber and has finished the cycle, it is pushed through the exchanger and preheats before entering the first expansion chamber.

22. At this point, attention will be focused on the transformations induced by the system to the working fluid, to understand how thermal energy is transformed into mechanical energy.

23. In this chamber the working fluid begins to undergo the thermodynamic transformations of the Stirling cycle. In contact with the heat of the chamber walls, the fluid increases its pressure, with a tendency, therefore, to increase its temperature as well. However, the expansion of the fluid can occur at a constant temperature because the working fluid is transferred, with a non-regenerative isochoric transfer, to the second expansion chamber, which is larger than the previous one. The increase in pressure due to heating therefore translates into mechanical work through the movement of the piston.

24. From the second expansion chamber, the fluid passes through the exchanger and is transferred to the first compression chamber, with a volume equivalent to the second expansion chamber, to comply with the dictates of the Stirling cycle which provides, as a third phase, a regenerative isochore transfer ; in fact, when passing through the exchanger, the fluid transfers heat (to the fluid which is simultaneously passing from the second compression chamber to the first expansion chamber).

25. Finally, the compression phase follows and the subsequent transfer of the fluid back to the hot side.

26. Referring to the best state of the art, it is also possible to realize a variant of the double-acting machine, with alternative pistons. In particular, it is possible to refer to the examples of alternative double-acting machines produced in the field of steam machines, which adopt, among the various possible solutions, the slide valve distribution system.

REALIZATION VARIANTS: THE ROTARY PISTON VARIANT

27. Given that the hinge of the present invention is to fix a flow mechanism of the working fluid of the circular type (chamber 1 / chamber 2 / chamber 3 / chamber 4 / chamber 1) and not already alternative (chamber 1 / chamber 2 and vice versa) we will have that, in place of the reciprocating pistons, connected to a classic connecting rod / crank crank, it will be possible to use rotary pistons, not dissimilar to those used, according to the best technique, in the volumetric operating machines (compressors and depressors, pumps and equivalents) . In rotary machines, the reciprocal geometry of rotor (or rotors, in multi-axis machines) and stator, with the possible help of other devices (e.g. vanes, in vane compressors) means that the volume of fluid introduced into the intake port is progressively compressed to be expelled from the delivery (i.e. exhaust) port. Symmetrically, with the same geometry, in the so-called depressors the cells used to receive the fluid undergo an inverse volumetric variation, progressively expanding. The compression ratio or the expansion ratio can be programmed upstream with an adequate design of the geometry of the components.

28. Having said this, it can be observed that, by using a device designed as an expander, exactly what is required by the Stirling cycle occurs: the fluid enters the cell initially at a low volume and expands; the tendency to lower the temperature is counteracted by the absorption of heat so that the fluid continues to expand (isotherm) by pushing the rotor in the direction of rotation, not unlike what happens in the presence of an alternative piston. At the end of the rotation, the volume of the cell has grown, as would have happened if it was an alternative piston, and therefore the fluid has performed work at a constant temperature (isothermal transformation); the hot fluid is expelled, passes through the exchanger and ends up in the rotary compression piston, where exactly the reverse occurs. The cell initially has a volume close to what the fluid had before expulsion (isochoric transfer) and then gradually shrinks and compresses. The fluid releases heat at the same time, so compression tends to occur at a constant temperature (isothermal transformation). From here, through the exchanger, the fluid returns to the expansion cell which has a volume close to the compression cell at the last stage (isochoric transfer).

29.11 Stirling cycle (two isotherms and two regenerative isochores) can also be performed with other rotary machines, other than those with cells with variable volume in the same rotation, machines in which, on the contrary, the inlet and outlet volumes are close ( so-called "blower" compressors). In fact, similar to the configuration described with four alternative piston chambers, each chamber assigned to a specific phase of the cycle, there can be a configuration with four rotary chambers (for example, Root-type lobe rotors or the like) in which the thermodynamic transformations are in any case reproduced. of the PV type diagram referring to the Stirling cycle, and being the mechanical work (in the expansion phase) collected by the rotary piston. It should be noted that, in the rotary piston configuration, the four chambers can be observed from a "dynamic" point of view, as the four thermal / volumetric values assumed by the working fluid are determined by the movement and geometry of the rotors inside the cavities in which they operate: they are, so to speak, “mobile” chambers, but this is not influential for the purpose of completing the Stirling cycle.

30. Evidently, in all rotary piston configurations, the pistons - expansion and compression - are connected and integral in rotation. In the rotary piston configuration there are no controlled valves, but loading and unloading ports that open and close according to the movement and geometry of the rotor (or rotors, in multi-axis rotary machines). Here the synchronism is programmed by the relative positioning of the compression and expansion rotors. It is clear that the stator rotor groups are made with materials suitable for thermal transfer needs.

31. An interesting application example of the machine, in the rotary piston configuration, can be done with the use of rotors very similar to the so-called Wankel, used with some success in AC motors. As can be seen from the drawing number. with the use of two Wankel-type stator / rotor pairs, the sequence of thermodynamic transformations typical of the Stirling cycle can be obtained in practice. Precisely, a Wankel stator / rotor pair, with the loading and unloading ports suitably redesigned and repositioned, can simultaneously carry out two opposite cycles of the intake and exhaust phases. The motion of the three-lobed rotor simultaneously forms two intake chambers, where the intake is obviously allowed by two different loading ports, and subsequently the fluid is expelled through two different exhaust ports, again due to the motion of the three-lobed rotor. lobes. By providing two stator / rotor pairs, hot and cold, it is possible to carry out the cycle already described previously in the alternative piston variant. Obviously, as an alternative to the three-lobe rotor and the Wankel stator, various realizations of stator / rotor pairs are also possible, capable of cyclically carrying out the suction / discharge phases, circulating the fluid in hot and cold environments and vice versa.

MANUFACTURING VARIATIONS: THE MULTI-STAGE

32. "Multistage" configuration: In the Stirling cycle the upper isotherm is characterized by a pressure P which decreases as the volume V increases. In a "multistage" configuration the various cylinders intercept parts of this isotherm: for example if from on the hot side there are 4 cylinders, the isotherm will be divided into three parts (the first cylinder is dedicated to isochoric transfer). The various pistons, on the expansion side, will exert the same force on the connecting rod-crank as the decrease in pressure is compensated by the increase in volume (i.e. with the same height of the cylinders, the base area increases). The same multiplication of the cylinders is performed symmetrically on the compression side. Then, in the event that there are sources of heat at various temperatures, there is also the possibility of combining the different temperatures to the various cylinders, obtaining the total cycle as a combination of several S cycles. An advantage of the "multistage" configuration is that it increases the useful surface for heat exchanges with the hot source and with the cold source and this allows machines of greater power to be created.

THE REVERSE COOLER CYCLE

33. From the aforementioned theory it is explained why the cycle of S. is a reversible cycle; it follows that if mechanical energy is administered and the cycle is run in the opposite direction, the side where the expansions occurred is now characterized by compressions and vice versa. The result is that heat is transferred from the colder tank to the warmer one. Constructively, the machine is the one shown above, the fields of application are environmental conditioning and cryogeneration.

BRIEF DESCRIPTION OF THE DRAWINGS

34. DRAWING 1 - This can be taken as a general engine diagram. 1 is the expansion side comprising the two expansion chambers 4; 2 is the compression side comprising the two compression chambers 3; 5 is the (main) exchanger. Referring to the Stirling cycle in the PV plane (pressure volume), it is necessary to follow the path of the fluid; it starts from its passage from the major chamber to the minor 3 (lower isotherm); the next step is the transit through the exchanger 5 where the fluid absorbs heat and then moves into the smaller of the two expansion chambers 4 (isochoric transfer from cold to hot); the passage from the minor chamber to the major expansion chamber 4 (upper isotherm) follows; finally there is the transit for the exchanger 5 where the fluid releases heat and then moves into the larger of the two compression chambers 3 (isochoric transfer from hot to cold) and so on.

35. DRAWING 2 - The diagram described in the previous drawing is implemented by ordinary cylinder-piston pairs 10, 11, 12, 13 equipped with pairs of on-off valves 14. The phases are indicated with 6, 7, 8, 9; the fluid passages from one cylinder to the other are represented by arrows in a continuous line 15 in the case of the first Stirling cycle and by arrows with discontinuous lines 16 in the case of the second cycle (in phase opposition with the first); the arrow also coincides with the exchanger which will be main in passages from 10 to 13 and from 12 to 11 and auxiliary d in passages from 13 to 12 and from 11 to 10. 17, solid line, indicates the position of the piston at the end of the phase considered .

36. DRAWING 3 - From the previous drawing, of which 18 is a partial reproduction, the detail relating to the auxiliary exchanger 19 is enlarged. of thermal transmission with the outside; only a pair of cooling / heating fins 21 are indicated, fins which contribute to the heat exchange; finally, passing from one end of the auxiliary exchanger to the other, the major axis of the elliptical section rotates by 90 ° (in the plane perpendicular to the axis of the tube that connects the two inlets 20) to create the turbulence in the working fluid artfully .

37. DRAWING 4 -Two ways of realizing the general diagram shown in drawing 1 are shown: ordinary pairs of rotating volumetric pumps with stator vane of different sizes 22, 23; alternatively, single rotary volumetric pump with rotor vane and special stator profile 33.

In the pumps 22, 23 the constituent elements are: 24 rotor, 25 stator, 26 rotation axis, 27 blade with spring 28, 29 and 31 loading port, 30 and 32 unloading port; here no valves are needed: the pair 22, 23 works as an expander if the inlet is 31 and the exhaust port 32 is connected, via an auxiliary exchanger, to the loading port 29, then having 30 as the final output; the pair 22, 23 works as a compressor if the input is 29 and the discharge port 30 is connected, via an auxiliary exchanger, to the loading port 31, then having 32 as the final output. It can be seen that the complete machine will consist of a pair 22, 23 in the expander configuration combined with another pair 22, 23 in the compressor configuration having connected, by means of the main exchanger, the exhaust port 30 of the expander with the loading port 29 of the compressor and the compressor discharge port 32 with the expander loading port 31. It is hardly necessary to specify that these four volumetric stator vane pumps will all have the same axis of rotation on which the mechanical energy generated will be available.

The pump 33 by itself already constitutes a complete machine which, like the previous one, does not use valves and moreover does not use auxiliary exchangers. Its constituent elements are: 34 stator, 35 rotor, 36 vanes with springs, 37 and 41 exhaust port, 38 and 40 loading port, 39 exchanger (main); the stator profile 34 is modeled in such a way that, during rotation, there is a progressive expansion on the one hand and progressive compression on the other. Since the left side (expansion) in contact with the hot source and the right side (compression) in contact with the cold source, constructively it will be necessary to pay attention to thermal bridges.

38. DRAWING 5 - The machine object of this invention can also be made using the suitably modified Wankel 42 engine.

43 is the stator on which the two loading ports 45, 47, the two exhaust ports 46, 48 have been obtained and from which the combustion chambers have been eliminated; then: 44 is the classic Wankel rotor; 42, 49, 80, 51 are the sequences relating to the suction function of the right half of the modified Wankel; 51, 52, 53, 54 are the sequences relating to the expulsion function of the right half of the modified Wankel; symmetrically the left half will behave.

From what has been seen in the previous drawing, it is automatic to assemble a pair (small and large) of these Wankels, for the expansion function and another pair for the compression function (along the lines of the pumps with stator vane illustrated in drawing 4) to then continue to complete the machine. In this case it must be said that you get a double car, since on each of these Wankels everything is doubled with the left side.

39. DRAWING 6 - The general diagram shown in drawing 1 can also be made from ordinary pairs of rotary lobe volumetric pumps of different sizes 55, 56. The constituent elements are: 57 stator, 58 lobes, 59 and 61 loading port, 60 and 62 exhaust port. As described in drawing 4 for the rotary volumetric pumps with stator vane, also here the couples for the expansion and compression functions can be formed in order to then assemble the complete machine. It can be pointed out that, given the characteristics of the lobes, the final result will be an even more continuous mechanical couple.

40. DRAWING 7 - The expansion can take place progressively in several cylinders (multistage) 63, 64, 65, 66 and the same can be said for compression 67, 68, 69, 70. In analogy to drawing 2, also here the steps of fluid from one cylinder to another are represented by arrows in a continuous line 71 in the case of the first Stirling cycle and by arrows with discontinuous lines 72, 73, 74 in the case of the second / third / fourth cycle (all out of phase both from the first cycle and among them); the arrow also coincides with the exchanger which will be main in passages from 63 to 70 and from 67 to 66 and auxiliary in passages from 70 to 69, from 69 to 68, from 68 to 67, from 66 to 65, from 65 to 64 and 64 to 63. What is illustrated in drawing 2 has similarly been realized and illustrated, with rotary devices, in drawings 4, 5, 6. Rotary machines replace reciprocating machines.

41. DRAWING 8 - The scheme described in drawing 2 concerned the engine; by inverting the direction of rotation, we obtain, with the same components, the refrigeration machine described; we have ordinary cylinder-piston pairs 83, 84, 85, 86 equipped with pairs of on-off valves 87. The phases are indicated with 91, 92, 93, 94; the fluid passages from one cylinder to the other are represented by arrows in a continuous line 88 in the case of the first Stirling cycle and by arrows with discontinuous lines 89 in the case of the second cycle (in phase opposition with the first); the arrow also coincides with the exchanger which will be main in the passages from 86 to 83 and from 84 to 85; the exchanger will be auxiliary in the passages from 86 to 83 and from 84 to 85; the solid line 90 indicates the position of the piston at the end of the phase considered.

ADVANTAGES OF THE INVENTION

42 with the proposed innovation it is no longer necessary to resort to complex kinematics to coordinate mechanics with thermodynamics. Unlike the classic configurations with crank mechanism (Alpha, for example) to which, with the due differences, the proposed machine refers, each chamber and therefore each piston is associated with only one phase of the Stirling cycle, and will perform, at any time, the same movement with the same speed, upwards or downwards: it will be an aspiration (downward movement) or an expulsion (upward movement) of the working fluid

43 The inventive leap with respect to the pre-existing technique can be effectively understood considering that to satisfy the requirements of the Stirling cycle, the working fluid must perform the thermodynamic transformations - that is, two isothermal transformations, expansion and compression, and two isochore regenerative transformations. - while the mechanics have only a functional importance, in the sense that its contribution is relevant only to the extent that the working fluid carries out the cycle, and nothing more. Therefore, there can be the most different mechanical forms, the most disparate kinematics and crank mechanisms, there may even be no crank mechanisms (Free piston system); but, ultimately, any mechanics is valid on condition that it imposes the required thermodynamic transformations on the fluid. In this regard, the invention provides for the simplest of the possible kinematics that satisfies this condition.

44. Regarding the description of the cycle carried out in the machine, it should be noted that the isothermal transformations, of expansion and compression, are always accompanied by a non-regenerative isochoric transfer, since the fluid in any case passes from one chamber to another in each of the four phases . However, in practice, these isochoric transfers, not being regenerative, have no influence on the sequence of the thermodynamic transformations carried out by the fluid and do not interfere with the correct completion of the Stirling cycle which, as known, provides for two isothermal transformations and two isochore regenerative ones.

INDUSTRIAL APPLICABILITY

45. The advantages of the system described relate to the simplification of construction, to the increase in power and obtainable efficiency. From the industrial point of view, the machine can be used in all sectors where the Stirling engine is used, through the enhancement of any thermal source, including waste. The system can obviously also operate in reverse cycle as a chiller or heat pump, supplying mechanical energy. Systems for electric generators, heat pumps, refrigerating machines and cryogenerators, possibly also traction motors, as an auxiliary or even main element can be created.

Claims (2)

CLAIMS Of the invention entitled "ONE-WAY FLOW STIRLING MACHINE" CLAIMS It claims: 1) Stirling cycle thermal machine, suitable for driving or operating function, comprising: - at least two thermally insulated environments (1, 2), even at different temperatures; - at least one compressor machine (3), suitable for being located in one of the aforementioned environments and built with materials that are at least partly thermally conductive, so as to exchange heat with the working fluid and with the environment in which it is located; - at least one expanding machine (4), suitable for being located in one of the aforementioned environments and built with at least partly thermally conductive materials, so as to exchange heat with the working fluid and with the environment in which it is located; - at least one heat exchanger (5), suitable for allowing the exchange of heat between the working fluid flows, having different temperatures, coming, respectively, from the compressor machine (3) and from the expander machine (4); - working fluid, suitable for running - cyclically and with unidirectional flow - a circuit, through compressor (3), exchanger (5) and expander (4); the fluid being suitable for exchanging thermal energy, also with the environments containing the machines (1, 2), in the said path between the compressor, exchanger and expander; said latter devices being able to cooperate to induce the working fluid to perform basically isothermal thermodynamic transformations, in the circulation through the compressor machine (isothermal compression) and through the expanding machine (isothermal expansion); and to perform regenerative transformations which tend to be isochore in the transfer, through the exchanger, from one machine to another; thus carrying out the Stirling cycle, direct or reverse. 2) Stirling cycle thermal machine, as per claim 1, characterized by the fact that the flow rate of the working fluid leaving the compressor machine is basically equivalent to the inlet flow rate of the expander machine, and, furthermore, by the fact that the flow rate of the working fluid outgoing from the expanding machine is basically equivalent to the inlet flow rate of the compressor machine, since said quantitative relationship between the flow rates of the working fluid is suitable for carrying out the isochorous transfer phases, typical of the direct Stirling cycle or reverse; 3) Stirling cycle thermal machine, as per claims 1 and 2, characterized by the fact that the compressor machine is a multistage machine, suitable for compressing the fluid in several phases (stages) with the aid of at least one suitable device to push the fluid into progressively decreasing spaces; 4) Stirling cycle thermal machine, as per claims 1, 2 and 3, characterized by the fact that the expanding machine is a multistage machine, suitable for carrying out the expansion of the fluid in several phases (stages) with the aid of at least a device suitable for pushing the fluid into progressively increasing spaces; 5) Stirling cycle thermal machine, as per claims 3 and 4, characterized in that, in the passage from one compression stage to another and in the passage from one expansion stage to another, the working fluid is passed through an exchanger device, suitable for exchanging heat even with thermal sources or with the external environment, in order to make the Stirling machine more efficient and powerful; 6) Stirling cycle thermal machine, as per claims 1, 2, 3, 4, 5, characterized by the fact that the expanding machine is placed in an environment with a higher temperature than the environment, isolated from the first, in which the machine is located compressor, and therefore the working fluid being induced to perform a direct Stirling cycle in transit between the compressor machine, the exchanger device and the expanding machine, so as to compress itself, releasing heat to the external environment, in the compressor machine; in order to exchange heat with the fluid at different temperatures - coming from the expander - in the exchanger device; in order to expand in the expander machine, acquiring heat with the external environment; in order to exchange heat with the fluid at different temperatures, coming from the compressor, in the exchanger device, to then pass through the compressor again, and repeat the cycle; said system being capable of supplying mechanical energy, suitable for producing electrical energy with the aid of a generator; 7) Stirling cycle thermal machine, as per claims 1, 2, 3, 4, 5, characterized by the fact that the expanding machine and the compressor machine are located in environments, however thermally insulated from each other, having a similar temperature compared to N ' external environment; therefore the working fluid being induced to perform an inverse Stirling cycle in transit between the compressor machine, the exchanger device and the expanding machine, following the administration of mechanical energy to the machine system; the working fluid being suitable for compressing itself by releasing heat to the external environment, in the compressor machine; in order to exchange heat with the fluid at different temperatures - coming from the expander - in the exchanger device; in order to expand in the expanding machine, acquiring heat from the external environment; in order to exchange heat with the fluid at different temperatures, coming from the compressor, in the exchanger device, to then pass through the compressor again, and repeat the cycle; so as to transfer heat from the room where the compressor machine is located, to the room where the expander machine is located; 8) Stirling cycle thermal machine, as per claims 1, 2, 3, 4, 5, 6, 7 characterized in that the volumetric compressor machine and the volumetric expander machine have at least one component in common; 9) Stirling cycle thermal machine, as per claim 8, characterized by the fact that the common components are manufactured with thermally insulating material, suitable for avoiding a thermal bridge effect. 10) Stirling cycle thermal machine, as per claims 1, 2, 3, 4, 5, 6, 7, 8, 9, characterized by the presence of at least one device suitable for collecting or administering mechanical work.