WO2008151751A1

WO2008151751A1 - Heat pipe and cooling device used in cryotechnology

Info

Publication number: WO2008151751A1
Application number: PCT/EP2008/004483
Authority: WO
Inventors: Jens Müller; Carsten BÜHRER; Jan Wiezoreck; Christoph Füllbier; Ingolf Hahn
Original assignee: Zenergy Power Gmbh
Priority date: 2007-06-11
Filing date: 2008-06-05
Publication date: 2008-12-18
Also published as: US20100155034A1; DE102007027355A1; GB2461668A; GB0919543D0

Abstract

The invention relates to a heat pipe or a cooling pipe used in cryotechnology, comprising a cladding tube (1) and a chamber (4) which is hermetically enclosed by means of a condensation element (3) on one end of the tube and an evaporation element (2) on the other end of the tube, and filled with a heat transfer medium suitable for cryogenics. The aim of the invention is to be able to cool supraconductive elements or components to the required transition temperature over a short period of cooling time, with high operating safety and in a highly economical manner. To this end, at least one cooling module (20) is built into the chamber (4) between the condensation element (3) and the evaporation element (2). Said cooling module comprises a tubular lateral surface (21) which is partially applied to the inner surface (1') of the cladding tube (1), and is provided with a guiding device (22), at least on the side of the condensation element, for deviating condensed and/or liquid heat transfer media towards the lateral surface (21). The invention also relates to a cooling device comprising a plurality of cooling tubes.

Description

Title: Wäπnerohr and cooling device for cryogenics

The invention relates to a heat pipe for cryogenics, with a cladding tube and a hermetically sealed by means of a condensation element at one end of the tube and an evaporation element at the other end of the tube, filled with heat transfer medium chamber. The invention further relates to a cooling device for cryotechnology for cooling superconductor components, in particular superconducting coils such as HTS coils (high-temperature superconductor coils), with at least one heat pipe.

The use of so-called heat pipes is not only in heat exchanger systems but e.g. also known for the cooling of microprocessors, solar modules or microelectronic cooling. A heat pipe (also called a "heat pipe") is a heat exchanger that allows a high heat flux density by utilizing the heat of evaporation and condensation of a substance. The operation of a heat pipe is based on circulating in a hermetically sealed tube, each having a heat transfer surface for the heat source and a heat transfer medium, preferably exclusively by gravity, to circulate through the phase transition of the heat transfer medium between liquid and gaseous To extract heat or material from the element. For the gravitational independent circulation the capillary effect of a shaft can be used in the heat pipe. Only as an example of the prior art for heat pipes is made to EP 483 324 Bl, in which a heat pipe is described in thermal coupling with a solar collector.

When using superconducting components such as superconductor coils, superconductor generators, linear motors with superconducting conductive coils, superconducting magnets od. Like. For example, it is necessary to cool the superconductive components to a temperature level below the transition temperature of the superconducting material. Since for most superconducting HTS materials, a temperature level below about 77 K must be achieved, the cooling is often done by means of cooling units in the form of cryocoolers with eg closed helium pressure circuit (dry cooling) or in a liquid bath, eg liquid nitrogen (77K at normal pressure). The classic cryogenic technique, which uses so-called cryogenic superconductors, even uses liquid helium for this purpose, which allows an operating temperature of 4.2K in the liquid bath. Since a temperature level below about -150 ° C is desired, numerous different refrigeration units or cryocooler for cryogenics, cryogenics and cryogenic technology can be used.

However, the liquid bath cooling has the disadvantage of a high cost, since a closed and pressure-resistant vessel must be guaranteed. On the other hand, if the liquid is allowed to evaporate, it must be constantly refilled from a reservoir. The direct contact of a refrigeration unit (cryocooler) with a component to be cooled has the disadvantage that the heat dissipation via heat conduction takes place in the material, so it is limited in terms of distance and the transferable power or requires the use of a lot of additional material that applications makes it undesirably difficult.

Only by way of example for the use of refrigeration units in the form of cryocoolers combined with a heat pipe in a superconducting motor is made to DE 102 11 363 Al, in between a superconducting coil receiving secondary part of a motor (rotor) and a cold head having a refrigeration unit fixed heat pipe is arranged, which projects axially into a co-rotating with the secondary part, lateral cavity and with a refrigerant (heat transfer medium) cooperates. The heat transfer medium (refrigerant) consists of a mixture of at least two refrigerant components, wherein the condensed refrigerant is conveyed via the heat pipe into the lateral cavity under groove tion of a Thermosyphoneffektes is introduced and in the cavity evaporating refrigerant via the heat pipe back to the condensation unit. From DE 102 11 363 Al it is known to use a heat pipe for cryogenics.

A conventional heat pipe for heating applications is known from US 2005/0257918 Al. In the chamber of the cladding tube, a built-in element is installed to divide the cladding tube into an upper and a lower half. The heat transfer medium which changes its state of aggregation to superheated steam at the evaporation element rises through the installation element to the condensation element and precipitates as condensate on the inner circumference of the cladding tube, the condensed drops running down from the condensation element to the installation element transporting the heat over the entire envelope. effect flat upper half. The mounting member serves as a collection ring for transferring the liquid heat transfer medium into an outwardly branching bypass line which returns liquid heat transfer medium in a closed line outside the chamber to the evaporation element.

The object of the invention is to provide a heat pipe for cryogenics and a cooling device with corresponding heat pipes, with which superconductive elements or components with high reliability and economy can be cooled with a short cooling time to the required transition temperature. Another object of the invention is to provide heat pipes with which also superconducting components of greater extent can be cooled.

The above objects are achieved in a heat pipe according to the invention in that in the chamber between the condensation element and the evaporation element at least one cooling module is installed, which partially rests with a tubular shell surface on the inner surface of the Hüll- and at least Kondensationselementseitig is provided with a guide, to deflect condensed and / or liquid heat transfer medium to the inside of the jacket surface of the cooling module. The liquid or condensed heat transfer The coolant flows downwards along the inside of the jacket surface of the cooling module, whereby the heat removal takes place selectively only in the region of the extent of the jacket surface. Since the heat pipe according to the invention for the cryogenics is to be used, and as a suitable refrigerant for the selected temperature range of the cryogenics is used as a heat transfer medium, the heat pipe can also be referred to as a cold pipe. The built in the heat pipe or cold tube, only partially relative to the total surface of the cladding tube on the inner wall applied cooling module causes the heat transfer medium or refrigerant only at certain areas of the cladding tube due to the direct contact between the outer surface of the cooling module and the inner surface of the cladding Cooling of the wall surface causes. At the points where there is contact between the cooling module and the cladding tube or on which the cooling module is positioned on the inside, it is therefore possible to selectively dissipate heat, in particular heat of a superconducting component, which is directly or indirectly connected to the zone of the cladding tube of the heat pipe or heat pipe ., Cold-oil communicates. The operation of the heat pipe (cold pipe) is based in a conventional manner that the refrigerant hermetically enclosed in the cold pipe, which is preferably a liquefied gas or gas mixture suitable for cryogenics, evaporates on supply of heat and reliquefies on the cooled condensation element becomes. The evaporating at warmer areas within the heat pipe refrigerant extracts heat on the heat of vaporization or enthalpy of vaporization of the corresponding zone, whereby the cooling effect is achieved in the region of the cooling modules. At constant pressure of the refrigerant, the temperature of the refrigerant (boiling temperature) also remains constant during the phase transition. It is understood that the condensation element for operating a heat pipe or cold pipe must be thermally coupled with a cryocooler to cool the condensation element to a temperature at which a phase transition gaseous-liquid takes place for the re-liquefaction of the refrigerant.

In the preferred embodiment, the guide of the cooling module is provided with passage slots, which lead to the inside of the Man- open surface to achieve a targeted application of the lateral surface with the liquid and dripping refrigerant on the condensation element. In the particularly preferred embodiment, the guide is designed as a cone or funnel-shaped, wherein it is preferably widened by the condensation element in the direction of the lateral surface. It is understood that each cooling module will normally have a certain distance from the condensation element.

In order to restrict the cooling effect of the cladding tube specifically to a specific zone, it is furthermore advantageous if the cooling module is provided with a guide element on the evaporation element side in order to lead away condensed and / or liquid heat transfer medium from the lateral surface. The guide element can also be advantageously designed as a cone or funnel-shaped. According to an advantageous embodiment, the guide element may have a sieve-like wall, consist of a perforated plate or be made of a perforated plate. The recesses in the screen or in the perforated plate serve to drain liquid refrigerant on the guide element in order to supply it to a further cooling module or to the evaporation element at the lower tube end of the heat pipe. Alternatively, the guide element may be provided with drainage slots.

In order to produce a cold pipe according to the invention with relatively little effort, it is particularly advantageous if the cooling module with guide,. Jacket surface and guide element made of metal, in particular a metal sheet, preferably made of steel, steel, copper, copper alloy or copper sheet. The cooling module can then by sheet metal forming, if necessary, without welds or the like. getting produced. For mounting a cooling module within the cladding tube is particularly advantageous when the assembly process by means of a shrinking process, namely by cooling the Kühltnoduls and / or simultaneous heating of the cladding tube, thus especially at the cryogenic temperatures, a secure positioning of the cooling modules and at the same time a secure Contact between the lateral surface of the cooling module and the inner surface of the cladding tube is ensured. The cryogenic refrigerant (heat transfer medium) may according to an advantageous embodiment consist of a mixture of at least two coolants with different condensation temperatures, such as a suitable for cryogenics helium nitrogen mixture (nH ₂ ) or nitrogen-oxygen mixture. Alternatively, the refrigerant may consist of a liquefied pure substance gas or an isotope thereof, in particular ⁴ He (liquid helium I), ³ He, neon, hydrogen or nitrogen (N ₂ ). The advantage of a multiphase refrigerant is that this refrigerant does not have an exact boiling point but a boiling range. The thermodynamic equilibrium may then shift to the higher boiling component of the liquid phase, causing a boiling point increase. Upon heating of a corresponding liquefied heat transfer medium (refrigerant), the phase transition begins when the temperature reaches the boiling point of that mixture constituent which reaches the lower boiling point. As the particles of this ingredient increasingly pass into the gas phase, the composition of the mixture changes locally, which also changes the boiling point until the boiling point of the other component is reached. At the same time, the pressure in the heat pipe can be adjusted higher or lower according to the requirements, so that a fine-tuning of the cooling area can be carried out here as well.

In a particularly preferred embodiment, the chamber facing side of the condensation element on a prismatic surface with drip tips, wherein preferably the drip tips in the assembled state are aligned with the passage slots in the cooling module. This measure also serves to selectively supply the liquefied at the condensation element refrigerant to the conical guide of the cooling module and the passage slots formed there, when the cold tube is used substantially vertically and the cycle of the refrigerant takes place due to gravity. The surfaces of the prisms may also be formed as fins to increase the heat exchange surface. The lamellae are perpendicular to the surface and the tips of the prism men are formed by the lamellae, ie the prisms form a superstructure.

In order to effect passively the circulation of the refrigerant between the cooling modules and the condensation element or between the evaporation element at the lower end of the tube and the condensation element at the upper end of the tube by means of gravitational forces, it is particularly advantageous if a shaft leading from the evaporation element to the condensation element, preferably laid concentrically to the central axis is laid, which can be formed in particular by means of a hollow tube. Through the cavity of the shaft or pit tube then gaseous refrigerant can rise unhindered to the condensation element.

A heat pipe according to the invention may have only a single cooling module in the chamber. In the preferred embodiment, however, a plurality of cooling modules are installed in the chamber to be able to cool by means of a cold pipe, if necessary, several superconducting, arranged outside the cold tube components to the necessary for the superconductivity operating temperature. In the case of several cooling modules in the chamber, the effect additionally occurs that by means of each cooling module a zone is formed, between which and the condensation element the refrigerant circulates until the zone has cooled to the desired cryogenic temperature level (ideally eg about 27K or 33K), only then liquid refrigerant passes through the perforated plate of the guide element to the cooling module of the next zone. If a cooling module has reached the temperature level, an approximately constant temperature profile arises between the condensation element and this cooling module, as a result of which the condensation zone also increases. In the beginning, the refrigerant in a deeper zone will evaporate as far as possible completely with high heat dissipation. Due to the extended condensation zone, however, this vapor can condense again to wet steam or droplets already at the overlying cooling module without the vapor having to rise up to the condensation element. The provision of a shaft is also advantageous in the case of a plurality of cooling modules, for which purpose the cooling modules preferably have a passage for a shaft or a hollow shaft pipe centrally. In order to ensure that evaporating refrigerant to the condensation element at the individual cooling modules, the shaft for each cooling module may have at least one radial opening above which the guide rests sealingly against the hollow tube.

The central hollow tube or shaft tube can in turn be connected to the plurality of cooling modules by a shrinking process, wherein preferably in the production of a heat pipe with multiple cooling modules first all cooling modules are attached to the hollow tube and then this unit, again by a shrinkage process, is introduced into the cladding tube. Alternatively, a combination of shrinking process in combination with soldering can be performed.

According to a further embodiment of the invention, the sheath tube can be designed annular and have an inner ring and an outer ring shell, wherein the cooling module rests with its lateral surface depending on the positioning of the component to be cooled on the inner surface of the inner ring or on the inner surface of the outer ring. The superconductive component to be cooled, in particular a superconductive coil, is expediently positioned on the annular jacket, on the inner surface of which the jacket surfaces of the cooling module (s) abut. An annular heat pipe is particularly advantageous for cooling large superconducting coils, ie coils with large inner diameters. The coils and corresponding to the heat pipe may be rotationally symmetrical about a central axis but may also be elliptical, oval or racetrack-shaped. In such embodiments of the heat pipe, an annular shaft can advantageously be formed between the cooling module (s) and that annular jacket on whose inner surface the lateral surfaces of the cooling module (s) do not abut. The guide devices and the guide elements are then aligned obliquely in such a way that the guide devices direct condensed heat transfer medium to the jacket surface on which the coil to be cooled is positioned, and the guide elements guide the heat transfer medium away from the jacket surface again. Further preferably, when the coil is positioned on the inner shell of the annular heat pipe, in the center of the component to be cooled be installed thermal insulation to produce a hot hole in the center of the coil. In order to be able to cool even long superconducting coils or superconductor elements uniformly, a heat-distributing element, in particular a copper tube, can additionally be arranged between the component to be cooled and the annular jacket.

The above object is also achieved by means of a cooling device for cryotechnology for cooling superconductor components such as superconducting coils, in particular HTS coils, which has at least one such heat pipe or cold tube. The cooling device has a receiving tube, in the inner chamber according to the invention a plurality of heat pipes are each arranged with at least one built-in cooling module, the condensation elements are thermally coupled to a cryocooler and their sheaths are at least partially in contact with the receiving tube. The cooling modules of a plurality, preferably all, of the heat pipes preferably lie in a common plane and a superconducting component is positioned in the same plane on the outer circumference of the receiving tube. In order to achieve optimum thermal coupling between the cold tubes and the components to be cooled cryogenically, inner thermal coupler elements in the same installation height as the cooling modules are formed in the interior of the receiving tube and / or an external one is present between the superconducting component and the outer jacket of the receiving tube thermal coupler element such as formed a copper ring. With such a cooling device not only, for example, superconducting coils can be cooled with a large inner diameter, but it can be achieved at the same time a high cooling capacity due to the large number of heat pipes or cold pipes. Even with such cold pipes long combinations of coils can be cooled, since a heat transfer over larger units is ensured.

In a cooling device is particularly advantageous if the heat pipes are anchored with their evaporation elements in a common receiving base, which is preferably formed thermally conductive and is thermally coupled to a heater. With the heater can then be prevented that in cooling mode, when all the cooling modules on the corresponding batch of the cladding tube cooled the desired temperature and even have the cryogenic temperature, icing at the foot of the heat pipe liquid refrigerant iced, since the additional heat supply, the refrigerant then evaporates, wherein the vapor rises via the shaft by convection or capillary action to the condensation element.

An advantageous field of application of corresponding cooling devices could be, for example, superconducting coil-equipped generators for the conversion of ocean waves or ocean currents into electricity. Another advantageous application is the cooling of an elongated, polysolenoid linear motor or an elongated or / and large-volume coil of a magnet for current limiters.

Further advantages and embodiments of the invention will become apparent from the following description of advantageous embodiments shown in the drawing. In the drawing show:

Fig. 1 is a longitudinal section through an inventive

Heat pipe for cryogenics, partially broken;

2 shows a side view of an embodiment of a cooling module for a heat pipe according to the invention;

3 shows in perspective an embodiment of a condensation element for a heat pipe according to the invention;

4 shows a cooling device with heat pipes according to the invention in side view;

Fig. 5 shows schematically a longitudinal section through the cooling device of Figure 4, partially broken.

Fig. 6 is a plan view of the upper head of the cooling device according to FIG. 4 and 5; and Fig. 7 shows schematically a longitudinal section through an annular heat pipe according to another embodiment for cooling large HTS coils.

The reference numeral 10 in Fig. 1 generally designated heat pipe or cryogenic pipe for cryogenics has a cylindrical cladding tube 1 as a connecting tube, which at its lower end with an evaporation plate 2 as an evaporation element and at its upper end with a condensation plate 3 as a condensation element or Capacitor element is closed. The connection between the tube shell of the cladding tube 1, the condensation plate 2 and the evaporation plate 3 takes place such that within the cladding tube 1 a hermetically sealed against the environment chamber 4 is formed. So that the heat pipe or cold tube 10 shown in FIG. 1 can be used for cryotechnology, ie for a temperature range below about -150 ° C, the chamber 4 is filled with a suitable, not shown cryogenic refrigerant as a heat transfer medium, in particular ⁴ He with a boiling point of about 4.23 K (Kelvin) at 1.013 bar, nH ₂ with a boiling point of about 20.4 K or N ₂ with a boiling point of about 77.35 K. The cryogenic refrigerant may also be from another liquid pure substance gas or gas mixture exist. For the operation of the heat pipe 10, the condensation plate 3 is thermally connected to a suitable cryocooler, not shown, with which the condensation element 3 can be cooled to a temperature at which liquid gaseous refrigerant trapped in the chamber 4 changes to the state of aggregation. The chamber 4 is preferably filled with the refrigerant at a pressure which is greater than atmospheric pressure, and the heat pipe 10 and all connections within the heat pipe 10 can withstand high overpressure. The heat pipe 10 is preferably designed for standing installation, in which the central axis of the jacket tube 1 is vertical or occupies a small angle to the vertical or vertical of <30 °.

According to the invention, at least one cooling module, designated in its entirety by 20, is installed in the chamber 4, which is shown in detail in FIG. 2, to which reference is first made. That preferably consisting of metal such as steel or copper or copper alloy cooling module 20 has a much smaller axial length than the sheath tube and it has a cylindrical, tubular lateral surface 21, to which a first cone or Kegeleletnent 22 connects, starting from the Transition 23 between the. Mantle surface 21 and the cone element 22 tapers conically or funnel-shaped upwards. The conical surface of the cone 22, widening towards the lateral surface 21, forms a guide device for directing liquid or liquefied refrigerant, which falls from above onto the conical element 22 due to the gravitational forces, to the lateral surface 21. The guiding action of the cone element 22 is reinforced by the fact that distributed over the circumference of the cone element 22 are several, for example four to eight guide slots 24 which extend to the edge or transition 23 and which allow the liquid and from above dripping Refrigerant through the guide slots designed as openings 24 to the inner surface 21 '(Fig. 1) of the lateral surface 21 can pass down to flow down there. The cone element 22 opens up flush into a circular dome 25, which forms a circular opening for a shaft tube or hollow tube 5 (FIG. 1), which is positioned concentrically to the axis of the jacket tube 1 of the heat pipe 10 and substantially over the entire height of the heat pipe 10 extends. At the lateral surface 21 is followed at the bottom by a second cone element 26, which in the illustrated embodiment of a screen plate or the like. is made, numerous sieve holes 27 and tapers conically from the lower cylindrical edge 28 of the lateral surface to the central axis. The second cone element 26 ends bluntly in a through hole 29 for the passage of the hollow tube or shaft tube 5. The recesses or holes 27 in the screen plate of the cone element 26 serve to further dissipate liquid refrigerant down or forward, so that liquid refrigerant not can accumulate within a single cooling module 20. The cone forming the guide 22 has substantially the same dimensions as the guide element forming cone, but is reversed in order to achieve an inflow liquid refrigerant to the cladding tube 1 or a flow towards the axis and at the same time to divert a flow of gaseous refrigerant within the cones towards the central axis.

In a heat pipe 10 according to the invention, at least one corresponding cooling module 20 is arranged between the evaporation plate 2 closing the lower tube end of the jacket tube 1 and the condensation plate 3 closing the upper tube end and inserted into the chamber 4 in such a manner that the outer surface 21 surrounds the inner surface with its outer side 1 'of the jacket tube 1 rests flat. The planar contact is preferably effected by means of an interference fit, which is achieved as a result of shrinkage of the cooling module 20 into the jacket tube 1, by e.g. heated for the shrinking process, the jacket tube 1 and at the same time the cooling module 20 is cooled in order to achieve by contraction or expansion joining of cooling module 20 and cladding tube 1.

With the built-in heat pipe 10 cooling module 20 is achieved that liquid refrigerant is selectively brought to the lateral surface 21 of each cooling module 20, whereby the cladding tube 1 in that area in which the cooling module 20 with its lateral surface 21 on the inner surface 1 'of Cladding tube rests, heat can be dissipated. A superconductive component such as a superconductive coil can therefore be positioned in a region on the outer circumference of the jacket tube 1 of the heat or cold tube 10, which is flush with the jacket surface of the cooling module 20, whereby one of these contact zone within the chamber 4 of the heat pipe 10 supplied liquid refrigerant can selectively and effectively dissipate heat from the superconductor components or superconductive coils, so that they are operated below the transition temperatures of the superconducting material. For the heat removal in this case the evaporation enthalpy of the refrigerant is utilized, which requires the refrigerant at the phase transition between the states of matter liquid-gaseous. The incorporation of the cooling modules 20 in the cold tube 10 has the special effect that the maximum cooling capacity is limited provided within a very short time in the area in which superconducting devices are positioned on the outer circumference of the heat pipe. In order to allow an optimal circulation of the refrigerant within the chamber 4 in the heat or cold tube 10, the hollow tube 5 forming the shaft has radial passages 6 of sufficient size substantially immediately below the dome 25 of the upper cone element 22 having the passage slots 24. through which refrigerant which has passed over into the gaseous aggregate state within a cooling module 20 into the inner tube 7 of the shaft tube 5 and from there can be supplied in gaseous form to the condensation plate 3 which has been cooled by means of the cryocooler. This is also supported by the funnel shape or conical shape of the cooling module 20.

Although Fig. 1 shows only a cooling module 20 within the chamber 4 of the cold tube 10. However, preferably over the height of the cold tube 10 evenly distributed more identical cooling modules 20 are arranged, with only the inside of the chamber 4 top, the condensation element 3 immediately adjacent lying cooling module 20 drops of liquid refrigerant from the condensation plate 3, while on the guide or cone elements 22 of the subsequent cooling modules liquid refrigerant drips, which passes through the holes 27 in the lower cone member 26. The evaporation plate 2 at the lower end of the heat pipe 10 then comes into play, although the lowest cooling module 20 within the chamber 4 can still pass liquid refrigerant down. In order to prevent accumulation of liquid refrigerant at the bottom of the cold tube 10, the evaporation plate 2 may be thermally or the like with a heater. be coupled, which prevents the liquid refrigerant at the bottom of the cold ear 10 ices. The on the evaporation plate 2 in the gaseous state of aggregation exceeding refrigerant can in this case pass through radial inlets 8 at the foot of the hollow tube 5 in the shaft inner tube 7 and flow from there to the condensation plate 3. For the radial slots 8, it may be sufficient to arrange the foot section 9 of the shaft shaft 5 at a suitable distance from the evaporation plate 2 or to support it by means of intermediate webs on this or on the jacket tube 1. Before the cooling modules 20 are mounted inside the chamber 4 of the cladding tube 1, preferably all the cooling modules 20 are produced by means of a shrinking process the hollow tube 5 shrunk before the assembly of shaft tube 5 and cooling modules 20 is used as a unit using thermal expansion / shrinkage in the cladding tube 1.

Fig. 3 shows an advantageous embodiment of a condensation plate 3 with the largest possible surface area to maximize the contact area for gaseous refrigerant and at the same time to achieve a targeted dripping or falling down of re-liquefied or liquefied refrigerant. The condensation plate 3 has for this purpose on its underside a prismatic surface 13 with a preferably the number of passage slots 24 in the uppermost cooling module 20 corresponding number of drip tips 14. Each drip tip may e.g. have four flat edges as prism surfaces. The thermal coupling of the condensation plate 3 with the cold head of a cryocooler or the like, for example via a copper rod. take place as a thermal bus or the cold head of a cryocooler can be connected directly to the condensation plate 3 of the heat pipe or the cold tube 10.

FIGS. 4 to 6 show an application example for the use of a plurality of cold pipes within a cooling device designated as a whole by 100. Each cold tube 10 in this case has a structure as described with reference to FIGS. 1 to 3 and each cold tube 10 has a plurality of cooling modules 20 over its height. The individual cooling tubes 10 are designed such that in all the cooling tubes 10, the cooling modules 20 are positioned at the same distance from the condensation plate 3 and the evaporation plate of each cold tube 10.

In the cooling device 100, a total of six cold tubes 10 are arranged at the same angular distance on a pitch circle about a central axis Z of the cooling device 100. The outer surfaces of the cladding tube 1 of each cold tube 10 preferably abut directly on a receiving tube 80, which is positioned concentrically to the central axis Z and includes all the cooling tubes 10 over their entire height. In the interior of this receiving tube 80, preferably only in those areas in which the cooling modules 20th are arranged within the cooling tubes 10, each cooling module level, an inner thermal conductor 81 is positioned as a thermal coupling element, which partially direct thermal contact between the entire outer surface of the cladding tube 1 of the individual cooling tubes 10 with the inner circumferential surface 82 of the receiving tube 80 causes as high as possible To achieve heat transfer between the receiving tube 80 and the cooling tubes 10 in the area in which the individual cooling modules 20 are positioned. In the exemplary embodiment shown, outer thermal coupling rings 85 are positioned at the regions of the outer jacket 83 of the receiving tube 80 that are in alignment with the cooling modules 20 and the inner thermal conductor elements 81, against which annular superconducting coils 90 abut with their inner ring.

The superconductor coils 90 may be cooled by the respective cooling modules 20 in the cold tubes 10 below the critical temperature of the superconductive material. All condensing plates 3 of the total here six cold tubes 10 are connected to each other via a coupling ring 70, to which the cold head 75 of a cryocooler, not further shown, is connected. The receiving tube 80 for the cold tubes 10 in turn is positioned within a tubular jacket 71, which is preferably designed as a cryostatic container. In the cooling device 100, all of the cold tubes 10, with their lower ends sealed to the evaporating plates, are thermally coupled in a receiving base 72 and are preferably associated with a heater to prevent the refrigerant within the individual, hermetically sealed, cold tubes 10 can freeze.

7 shows an exemplary embodiment of a heat pipe 210 for cooling a large and long superconducting coil 290. The heat pipe 210 is here rotationally symmetrical about the central axis Z ¹ and has an annular sheath 201 with an inner ring sheath 261 and an outer sheath 262 at the upper end of the two annular shells of the cladding tube 201, an annular condensation plate 203 with drip tips 214 is attached to its underside, and at the lower end an annular evaporation plate 202 is fixed in such a way. assumes that in the cladding tube 201, a hermetically encapsulated chamber 204 is formed, which is filled with a suitable cryogenic refrigerant. In the annular chamber 4 more cooling modules 220 are installed, of which only one is shown here. Each cooling module

220 rests with a cylindrical lateral surface 221 on the inner surface 261 'of the inner ring shell 261. Above each lateral surface

221 is an oblique, annularly around the inner ring jacket 261 circumferential guide 222 is formed, which deflects liquid or condensed refrigerant to the lateral surface 221. Below each lateral surface 221, the cooling module 220 has an inclined guide wall 226, which leads liquid refrigerant away from the lateral surface 221. The baffle 226 is provided with screen holes 227 so that refrigerant can drip down to another cooling module or to the evaporation plate 204. Between the cooling modules 220 and the outer ring jacket 262, an annular intermediate wall 265 is arranged, with which within the chamber 4, an annular shaft 207 between the cooling modules 220 and the outer ring jacket 262 is formed. The intermediate wall 265 is spaced from the condensation plate 203 and the evaporation plate 204, so that liquid and / or gaseous refrigerant can pass into the part of the chamber 204 in which the cooling modules are arranged. The Abtropfspitzen 214 on the condensation plate 203 are correspondingly radially within the intermediate wall 265. The intermediate wall 265 is immediately below the contact point between the here about 45 ° obliquely upwardly extending guide ring 222 and its contact point with the intermediate wall 265 provided with passages 206, thus within the cooling modules 220 can still rise above the pit evaporating refrigerant to the condensation plate 203. In the embodiment shown, the superconducting coil 290 to be cooled is positioned inside the inner tube shell 261. In order to achieve a good heat conduction between the cooling modules 220 and the coil 290 to be cooled, thermal coupling rings 281 are arranged outside the jacket tube 201, opposite the lateral surfaces 221. Since the coil 290 extends almost over the entire height of the heat pipe 210, is located on the outside of the coil 290, a copper tube 285 as a heat dissipation element, which in turn is in several places in each case in contact with the coupling rings 281. Those skilled in the art will recognize from the foregoing description numerous modifications which are intended to be within the scope of the appended claims. The figures show only preferred embodiments and in particular the number of cooling modules in a cold pipe or the heat pipe, the number of cold tubes in a refrigeration device, the thermal coupling between a cryocooler and the condensation elements of the individual cooling tubes can vary without departing from the scope of the appended claims , As a refrigerant, various pure substance gases, gases or gas mixtures, which are suitable for cryogenics or cryogenics, are used. The superconducting components and components can be attached directly to the cooling pipes or the receiving tube of the cooling device or indirectly to these or thermally coupled with these. The tubes may also be provided with overpressure relief valves, negative pressure evacuation valves and / or cooling fluid admission valves. In the annular heat pipe could be installed in the center of the coil, a thermal insulation, whereby in the center of the coil, a heat well. Alternatively, the coil could also rest on the outside of the outer ring jacket. The guide and guide wall of the cooling modules would then be inclined in accordance with obliquely to the outer ring casing and the lateral surface would be on this. The annular heat pipe could also oval or the like. be educated. Also, channels or gaps could be formed between the outside of the shell surface of the cooling modules and the inside surface to allow condensed liquid refrigerant to flow through those channels or gaps in the region of the cooling modules and then back from the inside surface with suitable means such as drip rings wegzuleiten and only in the area of the subsequent cooling module to lead back to the inner surface. In this case, the entire heat transfer medium could also only flow through the channels or gaps.

Claims

Patent claims

A heat pipe for cryogenics, comprising a cladding tube (1, 201) and a chamber (4, 204) hermetically sealed at the other end of the tube by means of a condensation element (3, 203) at one end of the tube and an evaporation element (2; ), characterized in that at least one cooling module (20; 220) is installed in the chamber (4; 204) between the condensation element (3; 203) and the evaporation element (2; 202), which is provided with a tubular jacket surface (21; 221 ) is partially in contact with the inner surface (I ¹ ; 261 •) of the cladding tube (1; 201), and at least one condensation element side is provided with a guide device (22; 222) for conveying condensed and / or liquid heat transfer medium to the inner side (21 ', 261'). ) of the lateral surface (21; 221) of the cooling module (20; 220) hinschulenken.

2. Heat pipe according to claim 1, characterized in that the guide (22) is provided with passage slots (24) which open to the inside (21 ') of the lateral surface (21) and / or the guide (22) formed as a cone or funnel-shaped is.

3. Heat pipe according to one of claims 1 or 2, characterized in that the cooling module (20) evaporation element side with a guide element (26) is provided to carry away condensed and / or liquid heat transfer medium from the lateral surface (21), wherein preferably the guide element (20). 26) is designed as a cone or funnel-shaped.

4. heat pipe according to claim 3, characterized in that the guide element (26) is designed as a sieve or consists of a perforated plate or is executed.

5. Heat pipe according to claim 3 or 4, characterized in that ■ the guide element is provided with preferably radially extending drainage slots.

6. Heat pipe according to one of claims 2 to 5, characterized in that the cooling module (20) with guide (22), lateral surface (21) and guide element (26) made of metal, in particular a metal sheet, preferably copper or copper alloy sheet or Sheet steel exists.

7. Heat pipe according to one of claims 1 to 8, characterized in that the cooling module (20) by means of a shrinking process by cooling the cooling module and / or heating of the sheath tube (1) is inserted into this.

8. Heat pipe according to one of claims 1 to 7, characterized in that the heat transfer medium is a mixture of at least two refrigerants with different condensation temperatures, wherein preferably the heat transfer medium is a helium-nitrogen mixture.

9. Heat pipe according to one of claims 1 to 8, characterized in that the chamber (4) facing side of the condensation element (3) has a prismatic surface (13) with drip tips (14) or a prismatic superstructure with drip tips, preferably the Drip tips (14) are aligned or almost in alignment with the passage slots (24) in the cooling module (20).

10. Heat pipe according to one of claims 1 to 9, characterized by one of the evaporation element (2) to the condensation element (3) leading, preferably laid concentrically to the central axis shaft (7), in particular by means of a hollow tube

(5) is formed.

11. Heat pipe according to one of claims 1 to 10, characterized in that a plurality of cooling modules (20) in the chamber (4) are installed.

12. Heat pipe according to claim 11, characterized in that the cooling modules (20) centrally have a passage for a shaft or a hollow tube (5), wherein the hollow tube (5) preferably for each cooling module (20) with at least one radial opening (6). is provided, above which the guide (22) rests on the hollow tube (5).

13. Heat pipe according to one of claims 1 to 12, characterized in that on the outer circumference of the cladding tube (1), in the same installation position as the lateral surface (21) of the cooling module (20), a superconductive component such as in particular a superconductive coil is positioned.

14. Heat pipe according to one of claims 1 to 13, characterized in that the cladding tube (201) is annular and has an inner ring shell (261) and an outer ring shell (262), wherein the cooling module (220) with its lateral surface (221) the inner surface (261 ') of the inner ring casing (261) or abuts against the inner surface of the outer ring shell.

15. A heat pipe according to claim 14, characterized in that the superconductive component to be cooled, in particular a superconducting coil (290), is positioned on the annular jacket (261), against the inner surface of which are the lateral surfaces of the cooling module (s).

16. Heat pipe according to one of claims 14 or 15, characterized in that an annular shaft (207) between the cooling module (220) and that annular jacket (262) is formed, on the inner surface of the lateral surfaces of / the cooling module / e are not present.

17. Heat pipe according to one of claims 1 to 16, characterized.- that in the center of the component to be cooled, a thermal insulation to achieve a hot hole is installed and / or that between the component to be cooled (290) and the Ring jacket (261) a heat distribution element (285), in particular a copper tube, is arranged.

18. Cooling device for cryotechnology for cooling superconductor components or superconductor coils, in particular HTS coils, with at least one heat pipe according to one of claims 1 to 17, characterized in that the cooling device has a receiving tube (80), in the interior (84) more Heat pipes (10) are arranged, the condensation elements (3) are thermally coupled to a cryocooler (75) and the cladding tubes (1) at least partially in contact with the receiving tube (80), wherein the cooling modules (20) of several, preferably all heat pipes (10) lie in a common plane and a superconductive component (90) is positioned in the same plane on the outer circumference (83) of the receiving tube (80).

19. Cooling device according to claim 18, characterized in that in the interior (84) of the receiving tube (80) inner thermal guide elements (81) in the same installation height as the cooling modules (20) are formed and / or between the superconducting member (90) and the Outer jacket (83) of the receiving tube (80) an outer thermal conductor (85) is formed.

20. Cooling device according to claim 18 or 19, characterized in that the heat pipes (10) are anchored with their evaporation elements in a common receiving base (72), which is preferably formed thermally conductive and thermally coupled to a heater.