WO2019201869A1

WO2019201869A1 - Thermal engine with an endless belt, endless belt, and method for producing an endless belt, and fibre for producing an endless belt

Info

Publication number: WO2019201869A1
Application number: PCT/EP2019/059696
Authority: WO
Inventors: Martin Huber
Original assignee: Martin Huber
Priority date: 2018-04-19
Filing date: 2019-04-15
Publication date: 2019-10-24
Also published as: DE102018109338A1; DE102018109338B4

Abstract

The invention relates to a thermal engine for generating mechanical energy with an endless belt (1), the length of which can be varied in the case of temperature changes, which endless belt (1) is guided around at least two deflection means (5, 6), wherein a shaft is coupled to one of the deflection means (5, 6) and is connected to a device for energy use, wherein the endless belt (1) has at least one first and one second belt run, wherein at least part of a belt run can be heated directly or by way of corresponding devices and/or part of said belt run or of another belt run can be cooled, wherein the endless belt (1) deforms spatially for the change in length, and has at least two layers (2, 3) of material with a different thermal expansion. The thermal engine (4) is improved by virtue of the fact that the first layer (2) comprises a first plastic, and the second layer (3) comprises a second plastic or carbon fibres, wherein the endless belt (1) is deformable reversibly under the influence of heat.

Description

"Heat engine with an endless belt, endless belt and process for producing an endless belt and fiber for making a

Endless belt "

The invention relates to an endless belt, a method for producing an endless belt and a heat engine and a fiber having the features of the preambles of the independent claims.

From the generic DE 10 2008 023 200 Al a heat engine with a corrugated endless belt is known, which is guided around two pulleys. The endless belt consists of a bimetallic corrugated transversely to the longitudinal direction. Each belt is assigned media for cooling and heating. The two shafts of the pulleys are mounted in the end of an elongated housing. The housing has two channels isolated from each other, in which run the stretch and the Zugtrum. In the deflection, in front of the pulleys, the channel openings are largely sealed by elastic curtains. Due to the channel of the expansion stratum, exhaust steam, hot air or hot water are routed counter to the direction of movement, a cooling medium, preferably cold air, flows through the channel of the draft channel. The two shafts of the pulleys are coupled by a gear. This ensures that the endless belt is always pulled by the stretch rope over the driven pulley to the pulling strand. Other embodiments with an auxiliary drive for the second deflection roller or a forced guidance of the expansion strand are also possible. The shaft of the driven pulley is further coupled to a transmission gear via which the rotational movement to z. B. a water pump, drive or fan is transmitted. A coupling with a generator is also possible. The first variants have the advantage that the heat energy is converted directly into mechanically effective energy. The device can be used particularly in warm countries on a mobile irrigation system as a drive or as a pump drive for a well using the heat of the sun. In an alternative embodiment, the endless belt has chambers with inwardly opening folds of the endless belt. The chambers have an elastic wall and are at a temperature increase strongly expanding gas or a liquid filled. The wall is preferably elastic only on one side, in the longitudinal direction of the endless belt, so that the stretching can take place only in one plane.

In the prior art also different double-layer components are known, which are used for shading.

These double-layer components have a first and a second layer, wherein the two layers are interconnected. The two layers have a different thermal expansion coefficient. The coefficient of thermal expansion indicates how the length of a substance changes approximately linearly at a certain temperature change. Both layers are made of a plastic. Because the layers have a different coefficient of thermal expansion, the double-layer component is reversibly deformable under the influence of heat, as is known, for example, from bimetallic workpieces. The double-layer components show a bimetallic effect.

EP 0 369 080 A1 discloses an endless belt in the form of a plastic sheet of a self-curling material. The plastic sheet consists of two layers, which have different expansion properties. In the ground state, the sheet is rolled up. The double-layer material consists of a sheet of polyethylene laminated on aluminum foil, which in turn has been applied to a stretched polyethylene film. A first layer of plastic material is heated and stretched while this pre-stretched layer is applied to an unstretched layer.

This double-layer components and the manufacturing method described therewith, have the disadvantage that the scope of such a double-layer component is essentially limited to the shading. The thickness of such films is especially in the micrometer range. The double-layer component generates at one Heat change only a small force, although sufficient for rolling, but no further use of this bimetallic effect allows.

Further double-layer components for shading are known, for example, from DE 196 29 237 C2. Here, a double-layer component for the temperature-dependent shading of components, in particular of solar collectors, of windows or the like is known. Here, a uniaxially stretched plastic film and an unstretched film and an insulating layer are used. The uniaxially stretched plastic film has a coefficient of linear expansion in the stretching direction, which differs as much as possible from the coefficient of linear expansion of the other film in the stretching direction. In particular, a uniaxially stretched polymer film is used as the inner film in combination with aluminum foil.

US 2011/0942174 A1 discloses a composite of a flexible polymer composition and a carbon nanotube film structure. When a voltage is applied to the carbon nanotube film structure, the polymer mass is heated, whereby the thermal expansion of the double-layer component is reversibly deformable due to the different thermal expansion coefficients. The thickness of the component is 0.7 mm. This double-layer component can not be used in a heat engine. The heat engine does not work when the double _S chichtbauteile must be heated externally by a power supply.

From US 2002/019189 Al a plastic double layer component is known. The two layers are formed by polyethylene and polyvinyl chloride. The thickness varies between 1 and 10 mils, ie between 0.0254 mm and 0.254 mm.

From JP 2001/341223 A, a double-layer component with a layer of polypropylene and titanium dioxide is known. As a result, a white layer is formed. This layer has been made in the form of a 20 cm square with a thickness of 0.4 mm. The other layer has 99% polypropylene and 1% "carbon black" with which the layer has been dyed black. The two strips were then glued together. Goal in the production This component is to achieve the highest possible change in the rate of thermal expansion coefficient. The layers are made by melting pellets and casting a plate. Paragraph 16 discloses that one of the layers may be admixed with a fibrous filler. However, the fibers are not unidirectionally aligned, but merely strengthen the composite.

From US 3,430,441 and FR854 030 a heat engine in the form of a wheel is known in each case. The wheel has a plurality of spokes, which are formed by double-layer components in the form of bimetallic strips.

From DE 26 17 577 a shutter in the form of a transparent sheet and a plurality of arranged on one side of the web slats is known. The angle between the surface and the web and the lamellar plane can be changed. The slats are flexible and made of a thermoplastic material, the slats are composed of several layers. The layers have different thermal expansion coefficients. When exposed to heat from sunlight, the lamellae change their shape. The slats are made of polyvinyl chloride (PVC).

From DE 27 09 207 Al a heat-sensitive venetian blind made of a closed-cell flexible foam plate is known, wherein the plate is divided by cuts in slats. The lamellae thus formed are laminated on some surfaces with a flexible sheet of a material with the lowest possible coefficient of thermal expansion. The flexible foam sheet may be foamed polyethylene. The laminated fabric consists of sheet steel.

It is an object of the invention to improve the generic endless belt, method and heat engine, and to provide improved fiber for producing an endless belt. This object of the invention is now achieved by a heat engine, an endless belt and a method and a fiber having the features of the independent claims.

The heat engine is designed to generate mechanical energy and has an adjustable in temperature changes in length endless belt which is guided around at least two pulleys. A shaft of a driven pulley is connected to a device for energy absorption, wherein the endless belt has at least a first and a second belt strand, wherein the first belt strand can be heated directly or by appropriate means and / or the second belt strand is coolable, wherein the endless belt for length change spatially deformed and having at least two layers of material of different thermal expansion, wherein a plurality of corrugation areas are formed for length change with temperature change at the endless belt. The first layer comprises a first plastic and the second layer comprises a second plastic or carbon fibers. The endless belt is reversibly deformable under the influence of heat.

The great advantage of the new heat engine is that it can be mounted directly on a roof, without the need for water pipes and pumps as in the known heat engine. The engine is more compact and efficient and much easier to produce in large quantities.

The heat engine drives in particular an asynchronous generator. The problem of different speeds with different levels of solar radiation is preferably solved by a transmission, in particular a CVT transmission (Continuous Variable Transmission). The transmission is arranged between the driven pulley and the asynchronous generator in the power flow. An inverter such as photovoltaic can be dispensed with. Making alternating current from a rotary motion is much easier than from a DC voltage. Alternatively, a frequency converter can be used together with an electrical generator.

Preferably, the tensile strand is passed through a warm medium and the strain of strain through a cool medium. Alternatively, it is conceivable to feed the tensile strand through a cool medium and the stretch strand through a warm medium. Both variants can be built. This depends on which side of the corrugated areas of the endless belt are curved during cooling or heating.

Further, in one embodiment, a portion of a first belt runner may be cooled and another portion of the same belt runner may be heated. If there are two bands, then four zones, one warm and one cold, can be used on each band.

Preferably, at least one strand is passed through a solar collector. It can be used a tubular solar collector. Preferably, the solar collector is formed by a box, which is covered with a particular rectangular disc. This design is particularly favorable.

It is possible to use other heat sources to drive the heat engine, for example. Geothermal or waste heat from industry or the residual heat of a power plant to generate electricity. For this purpose, it is possible to use tubes as rollers, or to store the rollers on pipes, wherein a hot tube, for example. By geothermal or waste heat is heated and thus the associated role is heated, the other tube and thus the other role cold is. This also allows the endless belt to be set in rotation.

Preferably, the two rollers are not mechanically coupled except through the endless belt. In a preferred embodiment, at least one roller cooperates with a ratchet so that the roller can only rotate in one direction. It is conceivable that both roles or more roles are defined in the direction of rotation by respective associated ratchets. It is conceivable that the rollers are coupled in addition to the endless belt by a coupling, possibly even with translation.

In particular, the endless belt has corrugated regions which can be sinusoidally or asymmetrically shaped. As a result of heating and cooling, the corrugated areas contract or become stretched so that a change in length occurs. It is conceivable that the endless belt does not have a double-layer structure with two layers with different coefficients of thermal expansion over the entire length but only at selected corrugation areas, so that the bimetal effect occurs only at these areas. For example, the endless belt can only two layers with different at the inwardly facing well regions or only at the outwardly facing well regions

Have coefficient of thermal expansion. Further, it is conceivable that the design, for example, the curvature of the inwardly facing well regions of the design, eg. The curvature of the outwardly facing well regions deviates.

The endless belt is preferably sinusoidal. This has the advantage that for easy production a corrugated sheet is usable, which is also sinusoidal. This has advantages in the production, but an arrangement with only wave crests without troughs is better, but more expensive to produce. Respectively. Both have their advantages and disadvantages. The big advantage is that one of the layers does not have to be interrupted to prevent the effects in the endless belt between wave trough and wave mountain leveling out.

It is possible to produce the endless belt by welding together of initially individual sections. Each section is simply bent. The sections are arranged side by side in a zigzag manner for welding, so that one section forms a wave crest and the adjacent section forms a wave trough. The sections are thus rotated by 180 ° to the adjacent section. Subsequently, the sections are each welded together at the joint. The thickness of the foil which is used to produce at least one of the layers is preferably either 0.25 mm, 0.5 or 1 mm so that the entire double-layer component is 0.5 mm to 1.5 mm, for example 1 mm or 1, 5 mm thick. The film may be formed as a polyamide film (PA film) or in particular as a polybutylene terephthalate Fobe (PBT Fobe). The thickness of the carbon fiber layer can also be varied. The thicker film is better because you can apply more power per surface and the bending effect is still strong enough.

The endless belt can be used in a heat engine, wherein the thickness of the endless belt is preferably at least 0.1 mm, preferably 0.5 mm. The thickness is preferably not less than 0.5 mm and not more than 5 cm, in particular not more than 1 cm, preferably not more than 5 mm. The thinner the endless belt, the greater the deflection, but the lower the forces exerted. With the endless belt according to the invention can be built in particular in a very cost-effective manner, heat engines, the endless belt can generate sufficiently large forces.

The width of the endless belt has no effect on the size of the deflection, but on the power that can apply the endless belt. The wider the endless belt, the greater the force. Preferably, the width of the endless belt is between 1 cm and 1000 cm, in particular between 50 cm and 200 cm. A larger width may be necessary if a larger thermal engine is to be designed. In a particularly preferred embodiment, the heat engine is dimensioned such that the endless belt has a width of lm.

The length of the endless belt also influences the deflection. The longer the endless belt, the greater the deflection and the greater the forces that can be applied by the endless belt. The length of the endless belt is preferably between 20 cm and 1000 cm. In a particularly preferred embodiment, the length can be between 100 cm and 200 cm. The endless belt preferably has a width between 0.1 m and 2 m, in particular of 1 m and a length of 2 to 5 m. The longer the endless belt, the more bipolymers work together and the faster the heat engine rotates.

The endless band is much longer than it is wide. The width is significantly greater than the thickness. The exact ratios of length to width to thickness are a matter of interpretation of the application.

The use of an endless belt with two layers of plastic has the advantage that the temperature range in which the endless belt can work is particularly useful. The usable temperature range may be in particular between -20 ° C and + 110 ° C. The maximum temperature for continuous use is below the melting temperature of the corresponding plastic, namely about 15 degrees below the Vicat softening temperature.

The endless belt is preferably formed as Bipolymerstreifen, which works like a bimetallic strip.

Examples of materials from which the layers can be made are, for example, polyethylene, in particular HDPE. Polyethylene is one of the most widely produced plastics in the world and therefore the initial cost is low. One ton of HDPE costs about € 1,600.00. Therefore, the cost of producing a strip is extremely low. A solar cell with the size of one square meter costs about 200,00 €. The solar cell has an efficiency of more than 10 percent. Although a corresponding heat engine with the endless bands has a lower efficiency than a solar cell, but at a fraction of the cost. The costs are significantly lower than those of a solar cell.

HDPE has a melting temperature of 130 degrees and a Vicat softening temperature of 105 degrees. One layer may consist of stretched and tempered HDPE and the other layer of stretched HDPE. The thermal conductivity of HDPE is 0.4 watts per Kelvin times meters. Becomes For example, a Bipolymerstreifen with a thickness of 1 mm and a width of 1 cm, a length of 10 cm and thus viewed from an area of 10 cm ² , so there is a heat conductivity of 0.4 watts per Kelvin. So assuming a working temperature difference of approximately 20 Kelvin, there is a heat conduction per strip of 8 watts or 8 joules per second. The heat capacity of HDPE is 1.9 joules per gram x Kelvin.

The polyethylene used has a high density of more than 0.955 g / cm ³ and / or a low degree of branching less than 1.3 branch per 1000 C atoms. This has the advantage that a particularly pronounced deviation of the thermal expansion coefficients in the layers can be achieved. The density of HDPE is more preferably 0.963 grams per cm ³ or more. Preferably, the polyethylene has 1 branch per 1000 C atoms. For example, Rigidex HD5502S from Ineos may preferably be used as the HDPE. This HDPE has a density of 0.955 grams per cm ³ with a degree of branching of 1.3 branch per 1000 carbon atom. Alternatively Rigidex HD6007S can be used by Ineos, the / cm has a density of 0.962 g of ³ and a degree of branching of less than 0.5 branches per 1000 carbon atoms.

It is desirable that the endless belt has a high thermal conductivity for the heat engine to have a high number of revolutions, since the cooling and heating of the endless belt is directly related to the number of revolutions.

Before the heat engine is described in more detail, the production of the endless belt will first be described in detail.

In a preferred embodiment, the layers of two strips of high density polyethylene (HDPE) are produced with very different coefficients of expansion. The two strips are then joined together to form a corresponding endless belt. The special properties of HDPE are particularly useful. HDPE can have both positive and negative thermal expansion coefficients and is therefore particularly well suited. In order to obtain desired properties, the HDPE must be stretched. For this purpose, an isotropic sample is first prepared. This can be done by extruding well above the melting temperature or by melting pellets in a mold. The melting point of the HDPE is approximately 130 degrees.

For stretching, the polyethylene can be extruded or pressed in the form of shoulder bars, which are subsequently drawn. The stretching can be done with a draw factor of 8. That is, the length of the shoulder bars or the extruded strand increases by eight times. When stretching, pay attention to inclusions and necks. The diameter decreases to about 1/3 during drawing. The density also decreases sharply to values of, for example, 0.8 grams per cm ³ . To increase the density, the samples can be treated for ten minutes at 5600 bar in a high pressure autoclave. The subsequently achieved coefficient of linear expansion, however, is independent of the pressure treatment, but the modulus of elasticity would be additionally increased. The E-modulus increases both by stretching and by the pressure treatment. A higher modulus of elasticity is desirable for use as a bimetallic replacement material because the mechanical stresses can be relatively high and a high modulus of elasticity compensates for this. The strips thus obtained should have a coefficient of linear expansion of about -24 x 10 ⁶ per Kelvin, ie a negative coefficient of linear expansion and thus contract when heated. This process is reversible in the temperature range of -20 degrees to +40 degrees. The coefficient of linear expansion is negative for stretched samples and becomes even more negative as the temperature increases. In order to obtain a strip with a particularly high coefficient of linear expansion, the strip must be tempered to just below the melting temperature. As a result, a linear expansion coefficient of + 160 x 10 ^{_ 6} per Kelvin can be achieved. If a stretched HDPE layer is annealed to just below the melting temperature, the maximum coefficient of thermal expansion results. So polyethylene can vary depending on the treatment have different thermal expansion coefficients, although chemically they are still the same substance.

Next, the two strips are combined together to form an endless belt. For this purpose, the two strips can be glued. The strips can either be glued over the entire surface of the contact surface or glued only at the ends of the contacts. The bonding can be done with molten plastic. Alternative joining methods of the strips are riveting, welding and rolling. The joining of the two HDPE strips is simplified by the fact that both parts are made of polyethylene.

Alternative plastic materials may be EVA (ethylene / vinyl acetate copolymer) having a linear coefficient of linear expansion of 25 x 10 ⁴ / K to 200 x 10 ⁶ 1 / K. Alternatively, linear polyurethane with a linear expansion coefficient of 210 x IO ⁶ 1 / K can be used. It is also conceivable polyamide 6 with a linear expansion coefficient of 95 x IO ⁶ 1 / K or high density polyethylene with a linear expansion coefficient of 260 x 10 ⁶ 1 / K use. Furthermore, it is conceivable to use nylon or polyamide with a linear expansion coefficient of 16 × 10 ⁶ 1 / K.

In one embodiment, the one layer of carbon fibers and the other layer of polyamide or nylon. This also makes it possible to produce a strong bimetal effect at a low cost. The working temperature can be significantly higher here. For example, the working temperature can be a maximum of 200 degrees. The carbon fibers can be used in particular in the form of carbon fiber rovings for producing the endless belt. The intense black of the carbon fibers is beneficial in direct sunlight on the endless belt.

A preferred embodiment comprises a layer of polyamide 6 or 12. This layer is bonded to a layer of unidirectional carbon fiber rovings. In order to increase the thermal conductivity of the endless belt, preferably at least one of the layers has graphene as an additive. The endless belts change shape faster when exposed to heat. The performance of the heat engine is increased. The graphene fraction can in particular be between 0.1% by mass and 80% by mass, in particular 1% by mass and 60% by mass, of the layer. In particular, a layer of polyamide, in particular polyamide 12, with an additional graphene component together with a layer with unidirectional carbon fiber rovings can form a corresponding endless belt.

Furthermore, it is conceivable to use two layers of polyamide with different thermal expansion coefficients.

In one embodiment, a layer of polybutylene terephthalate. Preferably, a layer of polybutylene terephthalate. Polybutylene terephthalate is even better than polyamide suitable because it is even more stable and more temperature resistant. The life of the endless belts is thereby increased. At higher temperatures and by the higher modulus of elasticity, the performance with polybutylene terephthalate is higher in the heat engine in addition to the increased efficiency due to the higher temperature difference. The other layer may be formed by unidirectional carbon fiber rovings. The layer of polybutylene terephthalate may further comprise a proportion of graphene to increase the thermal conductivity. The graphene content ranges between 0.1% by mass to 80% by mass, in particular 1% by mass and 60% by mass.

Preferably, no single-layer graphene is used, but Graphene Nano Platelets (GNPs). These GNPs then have about 7-8 layers, but can also have more or less, until it is by definition graphite. GNPs are cheap and still have a very strong effect on the plastic without large quantities. The thermal conductivity is increased so much that the reduced length expansion is compensated. In order to produce a corresponding endless belt, at least one of the layers is produced by extrusion, wherein the layers are joined together in a further step. It is conceivable that both layers are produced by extrusion. First, a rope-shaped blank having two layers is made, the ends of which are finally joined to form the endless belt. Further, the ends of the strand-like blank are glued together to form an endless belt.

In one embodiment, a layer is formed by carbon fiber rovings. The other layer can be applied by means of an extruder to this carbon fiber layer. The applied plastic layer and / or the carbon fiber layer are then preferably heated, after which the plastic layer and the carbon fiber layer are compacted. The densification and heating can be accomplished by pulling the two layers together through a taper in a heatable block. It can be a heatable metal block, for example. An aluminum block with a taper can be used. The taper may be wedge-shaped.

Alternatively, the endless belt can be made in a plastic press. The required plastic film can either be made of granules in the press itself or it can be used finished film. The film should be used in the direction of extrusion with the direction of the unidirectional carbon fibers. After pressing, the endless belt can be tempered in an oven. For this, the oven is heated above the melting point (eg 200 ° C) and the endless belt placed in the oven until it has laid completely flat. The plastic becomes very soft and the orientation is lifted. Subsequently, the plastic is taken out of the oven and cooled at room temperature very quickly, this gives the plastic a preferred direction and the bipolar effect is significantly increased. The bend is increased and the strength is also significantly increased. The layers are glued together and / or connected by the molten plastic.

Thereafter, in a further method step, the front ends are enclosed with plastic, so that the front ends of the carbon fibers are well connected to the plastic layer.

The two layers are joined together under pressure and heat. It is preferable that the corrugation regions are formed in the same step. However, the production of the corrugated areas can also take place in a subsequent step. The strand having the two layers may be passed through two intermeshing heated rollers, the rollers having a contour to create the corrugation regions. The rollers may have a sinusoidal outer contour which produces sinusoidal wave regions on the endless belt. The rollers are heated by means of heating elements. As they pass through the gap between the rollers, the layers are pressed together and joined together. It is conceivable that a roller has an interruption element for interrupting the structure. In particular, the element may be arranged in the apex region of the inward-facing or outward-facing corrugation regions, the interruption element weakening or severing one of the layers at this point. In particular, the interruption element can sever or weaken the plastic layer. This ensures that when heating or cooling the endless belt changes in length and the effects of the outwardly and inwardly facing wave areas does not cancel.

The band can also be heated by electricity as carbon fiber conducts electricity in such a way that it can image a very good heating wire. This is used eg in car seats for seat heating. In certain applications it may be useful to trigger the bipolar effect by current. Likewise, it may be useful to give the plastic a special shape, so that a snap effect similar to a Formgedächnismaterial arises. The plastic is under tension to a certain point during heating and the blocked expansion until the voltage then discharges. The same course then occurs on cooling. A comparison would be here bimetallic switches such as kettles whose clicking sound you can even hear.

The object is further achieved by a fiber according to claim 28.

The fiber is particularly suitable for producing an endless belt. The fiber has a first layer and a second layer, the two layers having different coefficients of thermal expansion, the first layer having a first plastic and the second layer having a second plastic or carbon fibers. The materials and material combinations for the layers mentioned with respect to the endless belt and listed in the description or the claims can be used correspondingly for the fiber. This fiber may also be referred to as bipolymer yarn. From the fiber, a woven or knitted fabric can be made. In addition to the use in an endless belt, there are other application examples. The fiber curls when exposed to heat and can be reversibly deformed.

The fiber can be used to make a fabric. In an advantageous embodiment, functional clothing (everything that one wears on the body) is produced with the fiber. The clothing can have conventional fibers and fibers according to the invention. The shape of clothing changes under the influence of heat and cold. The clothes can adapt to the outside temperature by making the fabric more dense and thus better insulated or widened to dissipate more heat from the body. The clothing could also have functions when putting on, for the perfect hold or emphasis of certain body regions.

In medical technology prostheses with the fiber or a plaster with the fiber are conceivable, which adapt themselves perfectly by the body temperature.

The fiber can also be used in adhesives. An adhesive strip with the fiber can be prepared so that when the strip is heated, the fiber contracts, thereby deforming the adhesive strip and thereby peel off the adhesive strip. In practical use, adhesive strips could be removed easily and without residue using a hair dryer.

One application is the use of fibers rather than shape memory metals in wafer production. The wafers (silicon for the production of processors) must be fixed very exactly and very strongly during the production but later also be loosened again. This is done in the prior art in that the shape memory metals are heated and thereby detach the adhesive. Instead, a fiber can be introduced into the adhesive. Generally, the bilayer fiber can be used as a cheap replacement for shape memory materials. Among other things, for fixing or detachment of adhesives or adhesive tape by heat and to perform functions.

The layers can thus be formed in a fiber. The fiber may be woven or knitted into an endless belt. The endless belt may further be woven or knitted from spun fibers, the fibers having two layers with different thermal expansion coefficients. The layers of the fibers may be formed from plastic and / or from carbon fibers as already described herein. In this case, preferably, a very thin bipolymer fiber is produced, such as a thread, which can then even be whirled, whereby the thread contracts sharply when heated. The threads can be woven into an endless belt and then used in the heat engine as an endless belt.

There are a variety of ways to design the endless belts according to the invention, the method and the heat engine and the fiber. Here, reference may first be made to the independent claims for parent claims. In the following, a preferred embodiment of the invention is explained in more detail with reference to the drawing and the associated description. In the drawing shows: 1 is a schematic sectional view of a part of a

Endless belt,

Fig. 2 in a schematic, perspective view of a

Heat engine

Fig. 3 in a schematic, perspective view of a

Extruder for producing an endless belt according to FIG. 1,

Fig. 4 in a schematic representation of another system for

Production of endless belts according to FIG. 1, and

Fig. 5 is a schematic representation of an arrangement for

Production of an endless belt with corrugated areas,

Fig. 6 is a schematic representation of another system for

Production of an endless belt with corrugated areas,

7 shows a schematic representation of a machine for producing corrugated areas in an endless belt,

Fig. 8 is a schematic representation of an endless belt with a

Carbon fiber layer and a PBT film, and

Fig. 9 in a schematic representation of a plant for producing a two-layer plastic fiber.

In Fig. 1, a part of an endless belt 1 can be seen. The endless belt 1 has two layers 2, 3. The layers 2, 3 are connected to each other over their entire surface. In a preferred embodiment, both layers 2, 3 are made of polyethylene. The one layer preferably has a positive thermal expansion coefficient and the other layer has in particular a negative or lower coefficient of thermal expansion. Both layers 2, 3 thus consist of a plastic. The endless belt 1 can also be referred to as a bipolymer strip. The layer 2 may be made of stretched polyethylene and the other layer 3 may be made of stretched and tempered polyethylene. In particular HDPE is used as polyethylene.

The total layer thickness of the endless belt 1, i. the sum of the thicknesses of the layers 2, 3 is in particular 0.1 mm or more than 0.1 mm, preferably 0.5 mm or more than 0.5 mm, the thickness of the endless belt (1) being 5 cm or less than 5 cm is. As a result, sufficiently large forces can be generated to insert the corresponding endless belt 1 in a heat engine 4, which is shown in FIG.

The heat engine 4 is used to generate mechanical energy with a temperature changes in the length changeable endless belt 1, which is guided by at least two deflection means 5, 6. As a deflection 5, 6 serve here crosses or stars. Alternatively, a gear can be used. The crosses intervene here in non-adjacent, outwardly facing wave areas of the endless belt.

It is possible to use rollers as deflection means 5, 6. The wheels can be made of shape memory foam, which adapts perfectly to the shape of the band and thus ensures optimum grip. Another advantage of the foam is the high coefficient of friction. The roles can be designed differently, since the bipolymers are heated on one roll and thus flat and on the other roll cold and compressed. A different size can also help define a preferred direction as a replacement / supplement to the ratchets.

A shaft (not shown in detail) is coupled to one of the deflection means 5, 6 and connected to a device for energy absorption. There may also be more than two deflection means 5, 6. The endless belt 1 has at least a first and a second belt strand, wherein the first belt strand can be heated directly or by appropriate means and / or the second belt strand can be cooled.

The one bandtrum is led through a warm zone 9, wherein the warm zone can be formed by a solar collector. The other Bandtrum is passed through a cold zone 10, wherein the cooling can be done by ambient air.

There are a plurality of corrugated areas for length change with temperature change formed on the endless belt. The endless belt 1 has, in particular, corrugated areas which are constructed or shaped asymmetrically by the material and / or by the design. The endless belt 1 is deformed by a change in length and is made of at least two layers 2, 3 of material of different thermal expansion.

As described, the first layer 2 comprises a first plastic and the second layer 3 comprises a second plastic or carbon fibers, wherein the endless belt 1 is reversibly deformable under the influence of heat.

The heat engine 4 is characterized in that the endless belt 6 is very inexpensive to produce and can additionally work in a temperature range from -20 degrees Celsius to 110 degrees Celsius, with a heat difference between the warm zone 9 and the cold zone 10, for example, 20 degrees Celsius is sufficient to drive the heat engine 4. The heat engine drives in particular an asynchronous generator.

FIG. 3 shows a preferred representation of a method for producing the corresponding layers 2, 3. There is a plastic extruder 14 which pushes a molten plastic through a nozzle 15. The nozzle 15 has a rectangular cut-out for the production of the corresponding strips. The strand 16 coming out of the nozzle is now first guided past a fan 17 and finally wound onto a roller 18. The winding speed of the roller 18 is preferably higher as the feed rate of the strand 16 through the nozzle 15, so that the strand 16 is stretched during winding. The strand 16 can be stretched 8 times. The wound strand material is now used to produce a corresponding layer 2, 3. Another strand material also produced in this manner is now additionally annealed in order to obtain a very different thermal expansion coefficient to the material of the other layer. These two strand materials are now cut accordingly in pieces of material of the strip length of the endless belt and connected to each other over the entire surface. This can be done by bonding with molten polyethylene. In particular, molten plastic is used to bond the layers. Gentle bonding is to be used, whereby the temperature of the layers is not increased in such a way that the effect of tempering is influenced. For example, a molten polyethylene wire may be used.

In this way, corresponding endless belts 1 can be produced particularly inexpensively.

It is conceivable to extrude a plastic, to stretch during winding and to provide it directly with a layer of carbon fibers, which are fed from another roll.

4, a further system for the production of endless belts 25 is shown. A carbon fiber layer 20 is first unwound from a roll 19 with carbon fiber rovings. By means of a plastic extruder 21, a plastic layer 23 is then applied to the carbon fiber layer 20 through a nozzle 22. Thereafter, the two layers are pulled through a taper to heat and densify the two layers. The taper is preferably formed in a heatable metal block. For example, a heatable aluminum block with a taper 24 is used. The plastic layer 23 and the carbon fiber layer 20 are heated as they pass through the taper and pressed together and thus compacted. The plastic layer 23 is thus printed on the carbon fiber layer 20. The result is a strand 25 of an endless belt. The strand 25 can initially wound on another roll 26. Thereafter, the strand 25 unwound again and the individual endless belt can be cut from the strand (not shown). Thereafter, in a further method step, the front ends are enclosed with plastic, so that the front ends of the carbon fibers with the plastic layer 23 are well connected.

In the manufacturing process (see Fig. 5), two large rollers 7, 8 are used, on which corrugated iron is clamped, so that the waves mesh like gears. The rollers 7, 8 are rotatably mounted on suspensions 27, 28. It is conceivable that both or only one roller 7, 8 is driven. The rollers 7, 8 are then arranged one above the other so that between the rollers 7, 8 of the blank 31 in the form of a loose double-layer component (the layers 2, 3 are in particular not yet connected) is formed. One or both rollers 7, 8 are heated by means of heating elements 29, so that the carbon fiber with the polyamide under the pressure between the rollers 7, 8 in the working zone 30 connects to each other. It is important to always interrupt the polyamide layer after one wavelength, so that the effects do not cancel, since in the wave, the curvature of the corrugated areas alternated and abolished under the influence of temperature. The interruption can be formed either in the troughs or on the wave crests by interruption elements 30 eg. Iron bars on the roller 8 and a device for cutting, for example. A sharp triangle, which then interrupts the polyamide layer.

After passing through the working zone 33 is formed from the blank 31, a strand 32 with corrugated areas from which the endless belt 1 can be made. The strand 32 is cut and the ends are joined together.

Fig. 6 shows another system for producing an endless belt. An upper plastic 34 and a lower plastic 35 are preferably provided on rollers (not shown) and pressed together by means of a press 36. The press 36 has a pneumatic cylinder 37, wherein the pneumatic cylinder 37 moves a pressing plate 38. The press 36 also has another press plate 39 as a counterpart. Between the press plates 38,

39, the upper and lower plastic 34, 35 are inserted and pressed by the press 36. The lower pressure plate 39 is in this case over a

Heater 40 heated. In particular, carbon fiber and the PBT or even polyamide can be pressed together under heat and pressure with the press. This results in the two-ply endless belt 25.

Fig. 7 shows a machine with which the endless belt its waveform is impressed by a heated blade or sword 41 presses kinks 42 in the endless belt. The sword works between two tubes 43, 44 or cylinders that form the peaks of the endless belt 25. The sword 41 is heated by means of at least one heating element 45 and moved by means of a pneumatic cylinder 46 transversely to the longitudinal extent of the endless belt 25. The sword 41 is shaped so that it fits perfectly on the rollers of the heat engine 1. The plastic is heated to such an extent (over the Schmelztempertaur) that it is melted by the sword 41st

Fig. 8 shows another embodiment of an endless belt 47, wherein first a PBT film 48 has been bent in a folding bench to get the waveform. Thereafter, carbon fibers 49 previously impregnated with epoxy resin have been applied. The carbon fibers 49 are cut to less than the width of the wave crests, so that in the kinks (wave troughs) no carbon fibers 49 are arranged.

FIG. 9 shows a plant or production machine for two-layer plastic fibers 50. A carbon fiber 51 is first unwound from a roll 19. By means of a plastic extruder 21, a plastic layer 23 is then applied to the carbon fiber 51 through a nozzle 22. After that, the carbon fiber 51 is pulled by a taper for heating and densifying the two layers. The taper is preferably formed in a heatable metal block. For example, a heatable aluminum block with a taper 24 is used. The plastic layer 23 and the carbon fiber are heated as they pass through the taper and pressed together and thus compacted. The fiber 50 comes out of the nozzle 22 that at the lower part of the fiber 50 of the plastic 23 is scraped off at the nozzle. At the top, the plastic 23 remains on the fiber 50. Because the fiber 50 itself is twisted, the finished fiber 50 is wrapped in a spiral with plastic 23, which enhances the bipolar effect. The plastic layer 23 is thus printed on the carbon fiber layer 20. The result is a strand 25 of a plastic fiber 50. The strand 25 can first be wound onto another roller 26. This fiber 50 may also be referred to as a bipolymer yarn.

One possibility is to use the fiber 50 to make functional clothing (everything you wear on your body). Clothes could adapt to the outside temperature by making the fabric more dense and thus better insulating or expanding to dissipate more heat from the body. The clothing could also have functions when putting on, for the perfect hold or emphasis of certain body regions. In medical technology, prostheses or a plaster with such a fiber 50 would be conceivable, which adapt perfectly to the body temperature. Other medical devices are also conceivable for use with bipolymer materials, such as a stent of bipolymer material or a fabric of fibers with corresponding layers. In all applications in medicine in the

Shape memory materials are used, these can be replaced by Bipolymermaterialien.

The fiber 50 can also be used in adhesives. The fiber may be ordered or disordered in the adhesive. Upon exposure to heat, the fiber 50 curls and deforms the adhesive, resulting in the release of the adhesive from the substrate. In this case, an adhesive strip is prepared so that when the adhesive strip is heated, the fiber curls or shrinks and thereby peel off the adhesive strip. In practical use, adhesive strips could be removed easily and without residue using a hair dryer.

This application is inspired by the use of

Shape memory metals in wafer production. The wafers (silicon for Production of processors) must be fixed very precisely and very strongly during production but later also be solved again. This happens because the shape memory metals are heated and thereby replace the adhesive.

In general, the fiber 50 can be a cheap substitute for

Shape memory materials are used. Among other things, for fixing or detachment by heat and to perform functions.

List of Reference Numerals: endless band

layer

heat engine

Cross / deflection

role

warm zone

cold zone

Insulation / parting plane

spring means

Plastic extruder

jet

strand

Fan

role

Roll with carbon fiber rovings

Carbon fiber layer

Plastic extruder

jet

Printed plastic layer

Aluminum block with taper for heating and compaction of both layers

Strand for endless band

Roll for winding

suspension

heating element interruption element

Blank / loose double-layer component stranded form with corrugated areas working zone

plastic

Press

pneumatic cylinder

press plate

heater

sword

kinks

pipe

heating element

pneumatic cylinder

endless belt

PBT film

Carbon fiber

two-layer plastic fiber carbon fiber

Claims

Claims:

1. Heat engine for generating mechanical energy with a at

Temperature changes in the length variable endless belt (1) which is guided around at least two deflection means (5,6), wherein a shaft is coupled to one of the deflection means (5,6) and with a

Device for energy reduction is connected, wherein the endless belt (1) has at least a first and a second Bandtrum, wherein at least a portion of a Bandtrumes can be heated directly or by appropriate means and / or a part of the same or another Bandtrumes coolable, the endless belt ( 1) to

Length change is spatially deformed and at least two layers (2, 3) material of different thermal expansion, characterized in that the first layer (2) comprises a first plastic and the second layer (3) comprises a second plastic or

Carbon fibers, wherein the endless belt (1) below

Heat influence is reversibly deformable.

2. Heat engine according to claim 1, characterized in that the thickness of the endless belt (1) is at least 0.1 mm, wherein the thickness of the endless belt (1) is 5 cm or less than 5 cm.

3. Heat engine according to one of the preceding claims, characterized

in that a strain (8) through a warm area, for example. A chamber with warm medium (7) or

Sun reflectors, and a Zugtrum (9) through a cool area, eg. A chamber with cool medium (6) is guided.

4. Heat engine according to one of the preceding claims, characterized

characterized in that the endless belt (1) has corrugated areas.

5. Heat engine according to one of the preceding claims, characterized

characterized in that the outwardly and inwardly facing well regions are at least partially formed differently.

6. Heat engine according to one of the preceding claims, characterized in that at least one of the layers (2, 3) is interrupted or weakened in the outwardly or inwardly facing well regions.

7. Heat engine according to one of the preceding claims, characterized

characterized in that the deflection means (5, 6) are formed as a cross or star.

8. Heat engine according to one of the preceding claims, characterized in that the media for cooling and heating against the direction of rotation of the endless belt (1), each thermally insulated, are each guided in a housing in which run the two Bandtrume.

9. Heat engine according to one of the preceding claims, characterized in that the endless belt (1) or more parallel endless belts are guided in particular with the Zugtrum in a solar collector.

10. endless belt (1, 47) with a first layer (2) and a second layer

(3), wherein the layers (2, 3) are interconnected, the two layers (2, 3) being different

Thermal expansion coefficients, wherein the endless belt (1) can be used in a heat engine according to one of the preceding claims, characterized in that the first layer (2) comprises a first plastic and the second layer (3) comprises a second plastic or carbon fibers, wherein the Endless belt (1) is reversibly deformable under the influence of heat.

11. An endless belt according to claim 10, characterized in that the thickness of the endless belt (1, 47) is at least 0.1 mm, wherein the thickness of the endless belt (1, 47) is 5 cm or less than 5 cm.

12. An endless belt according to claim 10 or 11, characterized in that the thickness of the endless belt (1) is at least 0.5 mm.

13. Endless belt according to one of the preceding claims, characterized in that the width of the endless belt (1) in the range between 1 cm and 1000 cm hedges.

14 endless belt according to one of the preceding claims, characterized in that the length of the endless belt (1) is between 20 cm and 1000 cm.

15. An endless belt according to any one of the preceding claims, characterized in that at least one of the layers (2, 3) consists of polyethylene, wherein the polyethylene has a density of more than 0.955 g / cm ³ and / or a degree of branching of less than 1.3 Branching per 1000 C atoms.

16 endless belt according to one of the preceding claims, characterized in that one layer (2) stretched and tempered HDPE (high density polyethylene) and the other layer (3) stretched, untempered HDPE.

17. An endless belt according to one of the preceding claims, characterized in that a layer comprises carbon fibers.

18. An endless belt according to one of the preceding claims, characterized in that at least one of the layers comprises polyamide.

19. An endless belt according to one of the preceding claims, characterized in that a layer of polybutylene terephthalate (PBT), in particular consists of polybutylene terephthalate.

20. An endless belt according to one of the preceding claims, characterized in that at least one of the layers graphene, in particular Graphene Nano Platelets has as an additive.

21. An endless belt according to one of the preceding claims, characterized in that the layers (2, 3) are formed in a fiber, wherein the fiber is woven or knitted into an endless belt.

22. A method for producing an endless belt according to any one of the preceding claims, characterized in that at least one of the layers (2, 3) is produced by extrusion, wherein the layers are joined together in a further step.

23. Method according to the preceding claim, characterized in that the layers (2, 3) are glued together.

24. Method according to the preceding claim, characterized in that the layers (2, 3) are connected by molten plastic.

25. The method according to any one of the preceding claims, characterized in that a plastic layer (23) by means of an extruder (21) on a carbon fiber layer (20) is applied, wherein the applied plastic layer (23) and / or the carbon fiber layer (20) heated is / are, wherein the plastic layer (23) and the carbon fiber layer (20) are compacted.

26. The method according to any one of the preceding claims, characterized in that under heat the corrugated areas are formed when passing through two intermeshing rollers (7,8).

27. Method according to the preceding claims, characterized in that the layers (2, 3) are heated while passing through the rollers (7, 8) and joined together under pressure.

28 fiber (50), in particular for producing an endless belt (1, 47), characterized by a first layer and a second layer, wherein the two layers have different thermal expansion coefficients, wherein the first layer comprises a first plastic (23) and the second layer comprises a second plastic or carbon fibers (51).