WO2011160622A1

WO2011160622A1 - Supercharged expansion motor

Info

Publication number: WO2011160622A1
Application number: PCT/DE2011/001386
Authority: WO
Inventors: Hans Jürgen RATHKAMP
Original assignee: Rathkamp Hans Juergen
Priority date: 2010-06-11
Filing date: 2011-06-10
Publication date: 2011-12-29
Also published as: DE102010023422A1

Abstract

In the case of an apparatus for converting thermal energy into a rotary movement of a drive shaft, in particular an expansion motor, having at least one thermal reactor, which has at least one cold region and hot region and at least one pressure chamber with a displacement piston, which is accommodated in a rotatable manner in the interior and which accommodates a compressed gas which moves cyclically back forth between the cold region and hot region by means of the displacement piston, and having at least one actuator for converting at least the cyclic change in volume of the compressed gas into a rotary movement of the drive shaft, wherein the actuator has at least one working piston, which is retained in an axially movable manner in a working chamber, and a coupler gear mechanism, which converts the linear movement of the working piston to the rotary movement of the drive shaft, and wherein the working chamber is coupled, at least with pressure-channelling action, to the pressure chamber of the thermal reactor, each working chamber of the actuator is designed such that it is filled with a working fluid which moves the working piston and has a low level of compactability.

Description

Highly charged expansion engine

The invention relates to a device for converting thermal energy into a rotational movement of a driven shaft, in particular an expansion engine, with at least one at least one cold and

Thermoreactor having hot area, which has at least one pressure chamber with a rotatably received in its interior displacer, in which a cyclically reciprocated by means of the displacer between the cold and warm area compressed gas is received, and at least one cyclic at least

Volume change of the compressed gas in a rotary motion of the drive shaft changing actuator.

Devices of known type have the function similar to a Stirling machine, by means of which an "inferior" form of energy, such as

Heat energy in the form of waste heat, in a "high-quality" and thus more usable form of energy, primarily mechanical energy to be converted.A compressed gas, such as air or a clean gas, such as helium, alternately heated and cooled, resulting in a continuous pressure and Volume change of the compressed gas and a resulting

Movement of an actuator has the consequence. From DE 198 09 847 A1 a Stirling machine is known, which comprise at least one cold and warm region having a thermal reactor with at least one pressure chamber in which a displacer is rotatably received. By means of the displacer, a compressed gas located in the pressure chamber between the cold and warm area is cyclically reciprocated. As a result, in particular in conjunction with the alternating heating and cooling of the compressed gas, a continuous pressure and volume change of the compressed gas causes, which in turn has a movement of the actuator and thus ultimately a rotational movement of the drive shaft result.

In this case, the actuator according to DE 198 09 847 A1 has a likewise rotatably received, designed as a rotary piston working piston, which is in particular coupled to the displacer via a shaft. The displacer and the rotational movement of the drive shaft generating actuator thereby form a rotor unit, which is a structurally complex configuration, in particular of the heat energy converting mechanical components of such Stirling machines. The production of prescribed Stirling machines also has to be done while maintaining a relatively high accuracy or low manufacturing tolerances in order to achieve a relatively high efficiency.

The invention is therefore an object of the invention to improve a device of the aforementioned type in that a relatively high

Efficiency is achieved in a simultaneously advantageous simple embodiment of the device.

The object is achieved according to the invention by a device having the features of patent claim 1. Advantageous developments and

Embodiments of the invention are specified in claims 2 to 16. In a device for converting thermal energy into a rotational movement of a driven shaft, in particular a Stirling machine, having at least one thermoreactor having at least one cold and warm region, which has at least one pressure chamber with a displacer rotatably received in the interior, in which a means the displacer between the cold and warm area cyclically reciprocating compressed gas is received, and with at least one cyclic change in volume of the compressed gas in a rotary motion of the drive shaft changing actuator is provided according to the invention that the actuator at least one axially in a working chamber movably held working piston and a linear movement of the working piston in the rotational movement of the drive shaft converting coupling gear, wherein the working chamber is at least pressure-conductively coupled to the pressure chamber of the thermoreactor.

The separate embodiment of the actuator with at least one axially movable in a working chamber held working piston is a structurally advantageous possibility for the design of a device for converting thermal energy into mechanical energy, in particular in a rotational movement of a drive shaft. The production of the expansion engine according to the invention is thereby advantageously simplified, as with the separate, mechanically independent from one another education of the displacement piston and the actuator a simplified seal can be ensured to the outside. By a pressure change in the pressure chamber and an associated change in volume of the compressed gas, a correspondingly directed force acts on the working piston of the actuator, whereby it is moved in the working chamber in the axial direction. In this case, the working chamber, which may be formed as a cylinder, at least pressure-conductively connected to the pressurized gas-containing pressure chamber of the thermoreactor. In this case, the pressure-conducting connection between the chambers may also comprise a media-conducting connection. To convert the linear movement into a rotational movement of the drive shaft, in particular a coupling gear is used, such as a crank mechanism. According to an advantageous development of the expansion engine is provided that each working chamber of the actuator is designed such that it is filled with a working piston moving the working piston, a low compressibility having working fluid. The use of a working fluid within the working chamber and predetermined connection areas of the actuator has, on the one hand, the advantage that an improved sealing of the movable working piston to the wall of the working chamber can be ensured. In contrast to a compressed gas used in the thermoreactor of the device, such as helium, a working fluid in the region of moving component surfaces and their gaps is not so volatile, so that it can be operated at higher pressures. On the other hand, the use of a generally nearly incompressible working fluid has the advantage that here, in contrast to the use of only one compressed gas, which is then also used for movement of the working piston, the dead volume is reduced, which is advantageous to the efficiency of the invention Device affects. In this case, the compressed gas can act directly on the working fluid to transmit pressure, it being ensured that the compressed gas never flows into the working chamber. The pressure chamber has at least one pressure line as a connection to the working chamber, in which already preferably the incompressible working fluid is present. Accordingly, only a volume change of the pressure gas received in the pressure chamber of the thermoreactor takes place. By a pressure change in the pressure chamber and a volume change of the compressed gas associated therewith, a correspondingly directed force acts on the working fluid in the

Working chamber and thus on the working piston of the actuator, whereby it is moved in the working chamber in the axial direction. In particular, any fluid having a relatively low compressibility and causing no corrosion on the mainly metallic components can be used as the working fluid. Furthermore, one of at least one

Working chamber leaking leakage flow of a working fluid of advantageously collected, for example, a leak oil collection device and be pumped back by means of a pump of the leak oil collection device into the corresponding working chamber. It is also conceivable, measured values, in particular Press to connect sensing sensors to the chambers of measurement, which receive the respective working pressure in the working chambers, so that then the deviations of the working pressures among each other are determined. The ascertained deviations can be compensated in particular with the leakage oil collecting device by filling certain working chambers with the working fluid.

The compressed gas and the working fluid are separated from each other in particular by at least one varying pressures transmitting release agent, whereby an advantageous separation of the compressed gas is achieved by the working fluid. By using a release agent or pressure transmitter according to the invention, which may preferably be formed as a metallic membrane, preferably with helium to be filled pressure chamber can be formed as a self-contained, metallically encapsulated area, so that an accidental escape of the compressed gas from the pressure chamber almost is excluded. For this purpose, metallic seals are also used in assembling the device according to the invention, which, due to the complete encapsulation of the rotatably received displacer, are advantageously not burdened by any, along it moving components. In this case, the pressure-transmitting, metallic separating agent between the compressed gas and the working fluid is also a dynamically moving seal, are advantageously avoided via the diffusion processes of the compressed gas into the working fluid.

Preferably, at least two working chambers are arranged in a radially aligned to the drive shaft plane, wherein the working chambers are arranged with their working piston and optionally coupled with the working chambers thermoreactors in particular at an angle of 180 ° to each other on both sides of the drive shaft. Thus, on the one hand ensures a balanced balance of power on both sides of the drive shaft. On the other hand, the device according to the invention can be charged relatively high in an advantageous manner, wherein by the Symmetrical arrangement of the working chambers and their working piston extremely high charges are even possible. Within a pressure chamber, for example, ambient pressures of 400 bar and higher may be present at ambient temperature, so that waste heat with a temperature of about 100 ° C can be used optimally for conversion into mechanical energy here in an advantageous manner. The reciprocating motion of the working piston is caused by the respective differential pressure in both working chambers continuously, inversely changing working pressures, as a result of offset by 180 degrees to each other control times of the displacer. A prerequisite for a uniform operation of the device is a uniform charging of the opposing pressure chambers. Preferably, the longitudinal axes of the working chambers, in particular designed as cylinders, are arranged coaxially, the common longitudinal axis extending radially through the longitudinal axis of the drive shaft. In order to generate a correspondingly high force on the drive shaft, for example, a plurality of such symmetrically arranged to the drive shaft working chamber arranged one behind the other along the drive shaft. Of course, more than two pistons extending approximately in a plane radially to the working shaft, may be arranged in a star shape around the working shaft, wherein the pistons preferably each have the same offset angle.

The coupling gear is in particular designed as a cross loop with a transverse to the direction of movement of the working piston aligned slide and a rotatably and slidably held in the sliding guide crank pin of the drive shaft. The use of a cross loop has the advantage that no tilting moments occur on the working piston and thus an advantageously improved sealing can be made to the sliding surfaces of the working chambers. The formation of a cross loop further has the advantage that the working pistons guided radially on both sides can in particular be designed in one piece, wherein a particular cuboid central part of the working piston is equipped with the sliding guide receiving the crank pin. In the Use of several successively arranged working chambers along the drive shaft whose crank pin are preferably arranged offset from one another, such that the inventive device, if a sufficient amount of heat is applied to the thermoreactor, starts by itself.

In addition, a plurality of filled with the working fluid working chambers may be arranged radially around the drive shaft of the expansion engine, wherein the working chambers with the axially movably held therein working piston and the coupling mechanism are at least part of a radial piston motor. With a particular star-shaped arrangement of a plurality of working chambers radially to the drive shaft and the formation of the working chambers with their working piston and mechanically connected to the power piston coupling gear as a radial piston motor is an advantageous way to convert the rectilinear piston movements in a rotary motion of the drive shaft by means of the in the working chambers given partially incoming and outgoing working fluids. In this case, the radial piston motor can be equipped with external or internal piston support.

As an alternative to the working chambers arranged radially around the drive shaft, the actuator can have a plurality of working chambers with center axes running parallel to one another, wherein the working chambers are arranged in a circle around a central region which forms. In order for a relatively compact arrangement of the working chambers is generated to each other, whereby an advantageous application of force to, for example, a mechanically connected to a drive shaft coupling gear is possible. Preferably, the working chambers and the axially movable therein

Working piston formed together with the coupling mechanism as axial piston. With the formation of the actuator as axial piston motor is the advantageous possibility, the stroke of the pistons within the working chambers in dependence on the required load or the existing heat energy change. The torques to be generated and rotational speeds of the axial piston motor present, for example, as a bent-axis motor, can thereby be optimally adapted. Accordingly, there is always an advantageous high efficiency of the actuator with respect to the respective present thermal

Given conditions.

Another development of the invention provides that the drive shaft and the displacer piston are coupled to each other via a coupling device, a fixed or varying angle of rotation to each other.

With the help of a coupling device can ensure a trouble-free synchronous or asynchronous transmission of the rotational movement of the drive shaft to the displacer for compliance with predetermined timing. In this case, the synchronous transmission of the rotational movement from the drive shaft takes place both in particular to a displacement piston pair arranged symmetrically on both sides of the drive shaft and also to possibly several displacement piston pairs arranged one behind the other along the drive shaft. Of course, the pressure chambers for the displacement piston can also be arranged in a star shape around the drive shaft. Depending on the number of used

Displacement piston pairs have these with respect to their timing, a predetermined twisting or offset angle to each other.

Preferably, the coupling device has at least one servomotor, which has a respective associated displacer piston in dependence on

Angle of rotation of the drive shaft adjusted. The use of a servomotor represents a structurally advantageous possibility for forming a connection-free coupling between the drive shaft and the particular encapsulated displacement piston. By means of the servomotors, phase shifts between drive shaft and displacer piston can be advantageous

Make way, so that the displacer can be passed slowly corresponding to a respective hot and cold area. For an improved heating or cooling and an associated expansion or compression of the compressed gas is achieved. To this end Measuring sensors are arranged on the drive shaft, which detect the rotation angle of the drive shaft and thus the position of the piston in the working chambers. About the permanently monitored angle of rotation of the drive shaft then the servomotors and thus the displacer are specifically controlled. The coupling between servomotor and displacer can be realized for example by means of magnetic couplings.

Alternatively, the coupling device has at least one belt drive, which is connected directly or indirectly with the drive shaft in a rotary manner and has pulleys coupled to the displacer piston by means of magnetic couplings. With the use of a belt drive, such as a toothed belt drive, a structurally advantageous possibility for synchronous transmission of the rotational movement between the drive shaft and the displacement piston associated pulleys is created. In order to ensure an encapsulated design of the individual pressure chambers, corresponding magnetic couplings are used with sufficiently high magnetic forces for non-contact coupling of the pulleys with the displacer. Of course, instead of a belt drive, the coupling device may have a chain drive or a spur gear for the synchronous rotation of the displacers to the drive shaft.

Each displacer piston is formed, in particular, from a plurality of disc bodies arranged one above the other with recesses for the compressed gas, stators forming regions of the pressure chamber wall projecting between the disc bodies. By between the disk body protruding stators an increased heat transfer surface and thus an improved heat exchange between the cold and hot area of the thermal reactor and the pressure gas located in the pressure chamber is ensured. With the improved heat exchange is always relatively quickly or suddenly rising and falling again pressure change in the constantly repeating cycle allows, which is advantageous to the efficiency of the device according to the invention effect. Each disk body of a displacer piston has a recess for the compressed gas to be moved in the pressure chamber, wherein the recesses of a displacer piston are always aligned congruent to each other. The disk body, for example, have a cylindrical

Shape on, over the entire height of a respective disk body a circular segment-like portion for forming the recess for the compressed gas is removed. The created by the recesses compressed gas volume is in a correspondingly high ratio to the given by gap dimensions and pressure lines dead volume.

Another development of the invention provides that each stator is subdivided into at least two stator sections forming a cold and a hot zone of the pressure chamber wall, via which either heat is transferred to the compressed gas present in the recesses or heat is withdrawn from the compressed gas. In this case, there is always a thermal separation of the cold and warm area of the thermoreactor forming stator sections. In particular, between the different temperature levels having stator sections, a regenerator may be provided in each case, wherein the regenerator is radially to both

Has sides of the displacer shaft extending portions. The regenerator sections arranged on either side of the displacer shaft are connected to one another in a heat-conducting manner. Each stator section forming a cold or warm region of the thermoreactor extends approximately over one third of the circumference of the pressure chamber wall.

It is within the scope of the invention that a respective stator section is equipped with at least one channel leading to a heating or cooling medium. Preferably, each of the stator sections projecting between two rotatable disk bodies of the displacer piston has a liquid one

Medium leading channel, initiated via the targeted heat by means of a correspondingly hot or heated medium in the thermoreactor or can be deducted from the heat over a correspondingly cold medium. As a heating medium can directly a waste heat stream be used. It is also conceivable to lead the waste heat stream to be used via a heat exchanger coupled to the device according to the invention, in which case a separate heating, cooling circuit is formed on the device exclusively as a heating medium and as a coolant between a heat exchanger and the thermoreactor is.

In particular, the displacer piston has a hollow shaft which has apertures associated with the recesses of the disk body, so that a pressure and media-conducting connection is produced between the inner diameter of the hollow shaft and the recesses receiving the compressed gas. The use of a hollow shaft for producing a pressure-conducting connection between the pressure chamber and the possibly separately formed actuator provides a structurally advantageous possibility for pressure transmission. The apertures formed as bores run radially to the longitudinal axis of the hollow shaft. Furthermore, the displacement piston is open at one of its ends, whereby the pressure and medium-conducting connection to the separating the pressure gas and the working fluid separation means, which is arranged in a pressure transmission region of the thermoreactor, is ensured.

An embodiment of the invention, from which further inventive features, is shown in the drawing. Show it:

Fig. 1: a perspective view of an inventive

Device with a partial section in the region of its actuator;

Fig. 2 is a perspective sectional view of an individual

Thermoreactor and sections of the actuator, and

Fig. 3: a detail view of the thermal reactor in section. 1 denotes a Stirling machine, which has a plurality of thermoreactors 2, 2 ', 2 ", each thermoreactor 2, 2', 2" being equipped with at least one pressure chamber 3, in each of which a displacer 4 (FIG. Fig. 2) is arranged. In this

Embodiment is in particular arranged at the lower end of each thermoreactor pressure-conductively connected to the pressure chamber 3 working chamber 5, in which a working piston 6 (Fig. 2) is held axially movable. The working piston 6 which forms part of the actuator 7 is in particular connected to a drive shaft 9 of the Stirling engine 1 via a coupling mechanism 8 which converts the linear movement of the working piston into a rotary motion. Furthermore, a coupling device 10 is provided on the drive shaft 9, which ensures a coupling of the drive shaft which maintains a fixed angle of rotation with the displacement pistons 4 of the thermoreactors 2, 2 " The belts of the belt drives 11, 11 'are guided in particular via pulleys 13, 13', wherein the belt pulleys are synchronously rotationally coupled to the respective displacement piston 4 by means of magnetic couplings 14 (FIG. 13 'and the

Displacement piston 4 are arranged in particular coaxially, which is also apparent from Fig. 2.

In Fig. 2 is a detail view of the thermoreactor 2 and a particular directly disposed thereon work chamber 5 is shown in section, and is intended in particular to illustrate the structure of the pressure chamber 3 and the pressure-conductive connection to the working chamber 5. The pressure chamber 3 has an approximately cylindrical basic shape, wherein within the pressure chamber 3, the displacer 4 is received rotatably. The displacer piston 4 is made of a plurality of disk bodies arranged one above the other

15, 15 ', 15 ", wherein each disk body has a recess 16, 16' (FIG. 3) for the compressed gas received in the pressure chamber -Wave 17 on which as a hollow shaft is formed and the recesses 16, 16 'of the disk body 15, 15', 15 "respectively associated, not shown breakthroughs has .. With its open end 18, the displacer shaft 17 is connected to at least one pressure line 19, which opens into a pressure transfer area 20 In particular in the pressure transfer region 20 is on one side of a respective release agent 21, 21 'directly in the volume changing pressure gas and on the other side About the directly on the release agent 21st 21 'and up to the working chamber 5 of the actuator 7 working fluid via at least one pressure line 22, a pressure relaying compound to the working piston 6 in the working chamber 5. The cyclically through the heating or cooling of the compressed gas generated pressure and Vo Lumenänderung acts on the release agent 21, 21 "and the nearly incompressible working fluid into the working chamber 5, so that a force acting in the longitudinal direction of the working chamber force on the working piston 6 rests and attacks and this moves accordingly. At the other end 23 of the displacer 17, a part of a magnetic coupling 14 is arranged, which is a non-rotatable

Coupling to a rotatably held at the top of the thermoreactor 2 pulley 13 produces, which in turn has the other part of the magnetic coupling 14. In this case, it is always ensured that the pressure chamber 3 of the thermoreactor is completely metallurgically housed pressure-resistant. As illustrated in FIG. 1, in particular two thermoreactors are symmetrical to

Drive shaft arranged. In this context, the working piston 6, 6 'preferably formed in one piece, wherein the working piston connecting approximately cuboid center region 24 has a transverse to the direction of movement of the working piston trained slide 25 for rotatably and slidably held therein crank pin of the drive shaft 9 for forming the linkage 8 , The movement of the working piston 6, 6 'is generated by the pressure difference between the prevailing in the respective associated working chambers 5 working pressures, the piston movements of the working piston 6, 6' in opposite directions to each other are. In this case, the respectively assigned displacement piston 4 of the thermoreactors arranged opposite each other assume a rotation angle offset by 180 degrees relative to each other. The use of more than two pistons is also conceivable, in which case the coupling mechanism 8 may be a conventional crank mechanism.

Fig. 3 shows an enlarged detail view of a portion of the thermal reactor in section, which illustrates in particular its structure. To the heat transfer from a hot area to the compressed gas and from the

Pressure gas to achieve a cold region of the thermoreactor, stand between the disk body 15, 15 'of the displacer 4 each stators 26, 26' to the displacement piston shaft 17 before. To increase the heat transfer surface of the disc body 15, 15 'and the stators 26, 26' are introduced a contactless interlocking ribbing 27 forming grooves and lands on the converging surfaces. Each stator 26, 26 'is divided into at least two stator sections 28, 28', each forming a cold zone and a hot zone. In addition, in addition to the cold and hot regions forming stator sections, a regenerator function acquiring stator section 28 is provided, which is arranged on both sides of the displacer shaft 16 between the stator sections 28, 28 '. In particular, in the one respective cold and warm area forming stator sections 28, 28 'are each a heating or cooling-carrying channels 29, 29' are provided, whereby the direct heat input or the direct heat dissipation into the interior of the thermal reactor 2, in particular in the stator 28, 28 ', takes place. For this purpose, 2 terminals 30, 30 'for introducing or discharging the heating or cooling medium are formed on the outer surface of the thermoreactor. The thermoreactor 2 can be composed of aufeinandersetzbaren segments.

Claims

claims

Device for converting thermal energy into a rotational movement of a drive shaft, in particular an expansion engine, with at least one thermoreactor having at least one cold and warm region, which has at least one pressure chamber with a displacer rotatably received in the interior, in which a displacer between the Cold and warm area cyclically reciprocating compressed gas is received, and with at least one at least the cyclic change in volume of the compressed gas in a rotational movement of the drive shaft changing actuator,

characterized,

in that the actuator has at least one working piston which is axially movably held in a working chamber and a coupling gear which converts the linear movement of the working piston into the rotational movement of the drive shaft, and wherein the working chamber is at least pressure-conductively coupled to the pressure chamber of the thermoreactor.

Apparatus according to claim 1, characterized in that each working chamber (5) of the actuator (7) with a working piston (6, 6 ') moving, a low compressibility having working fluid is filled.

Apparatus according to claim 2, characterized in that the compressed gas and the working fluid by at least one varying pressures transmitting release agent (21, 21 ') are separated from each other.

Apparatus according to claim 3, characterized in that the pressure chamber is formed by means of the separating means as a self-contained, the compressed gas encapsulating area.

Device according to one of claims 1 to 4, characterized in that at least two working chambers (5) are arranged in a radially to the drive shaft (9) aligned plane.

Device according to one of claims 1 to 5, characterized in that the coupling gear (8) as a cross loop with a transversely to the direction of movement of the working piston (6, 6 ') aligned sliding guide (25) and one in the sliding guide (25) rotatable and sliding movable held crank pin of the drive shaft (9) is formed.

Device according to one of claims 1 to 5, characterized in that a plurality of filled with the working fluid working chambers (5) are arranged radially around the drive shaft (9) around, wherein the working chambers with the axially movable therein held piston and the coupling gear at least part a radial piston motor are.

Device according to one of claims 1 to 4, characterized by a plurality of working chambers (5) with mutually parallel center axes, wherein the working chambers are arranged in a circle around a forming center region around.

Apparatus according to claim 8, characterized in that the working chambers (5) and the axially movable working piston are formed together with the coupling gear as axial piston.

Device according to one of claims 1 to 9, characterized in that the drive shaft (9) and the displacer piston (4) via a coupling device (10), a fixed angle of rotation to each other, are coupled together.

11. The device according to claim 9, characterized in that the coupling device has at least one respective associated displacer in dependence on the Drehwinkei the drive shaft adjusting servomotor.

12. The apparatus according to claim 10, characterized in that the coupling device (10) has at least one belt drive (1 1, 11 ') which is pivotally connected to the drive shaft (9) and by means of magnetic clutches (14) with the displacer (4) coupled pulleys (13, 13 ').

13. Device according to one of claims 1 to 12, characterized in that each displacer (4) has a plurality of superimposed disk body (15, 15 ', 15 ") with recesses (16, 16') for the compressed gas, wherein between the Disk body (15, 15 ', 15 ") projecting portions of the pressure chamber wall stators (26, 26') protrude.

14. The device according to claim 13, characterized in that each stator (26, 26 ') in at least two, a cold and a hot region forming stator sections (28, 28') is divided.

15. The apparatus according to claim 14, characterized in that a respective stator section (28, 28 ') with at least one heating or cooling medium leading channel (29, 29') is equipped.

16. Device according to one of claims 1 to 15, characterized in that the displacement piston (4) has a hollow shaft which has the recesses (16, 16 ') of the disk body (15, 15', 15 ") associated openings.