Heat exchanger for a joule-thomson cooler, and joule-thomson cooler

Abstract

A first aspect of the invention relates to a heat exchanger (30) for a Joule-Thomson cooler (10), comprising a main body (310) and at least one gas pipe (32) made from a material composed of ceramic and metal, surrounding the main body (310). A second aspect of the invention relates to a Joule-Thomson cooler (10), comprising: - a heat exchanger according to the first aspect, and - a casing (20), in which the heat exchanger is housed. A third aspect of the invention relates to a method for manufacturing a heat exchanger according to the first aspect, comprising at least one step of manufacturing the gas pipe comprising at least one step of forming the gas pipe by extrusion and a step of coiling the gas pipe.

Description

TITLE: JOULE-THOMSON TYPE COOLER HEAT EXCHANGER AND JOULE-THOMSON TYPE COOLER TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of Joule-Thomson type coolers equipped with a heat exchanger.

[0002] More particularly, the present invention relates to a Joule-Thomson type cooler, a Joule-Thomson cooler heat exchanger and a method of manufacturing such a heat exchanger. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Classically, Joule-Thomson type coolers provide cryogenic cooling of an element by quickly reaching low temperatures of around 120 Kelvin.

[0004] Typically, Joule-Thomson coolers are designed to achieve controlled expansion of a gas initially under high pressure. The temperature of the expanded gas drops sharply, allowing an element to be cooled in contact with it. Such a cooler is used, for example, to cool elements such as infrared detectors and / or electronic components.

[0005] Figure 1 shows an example of a conventional Joule-Thomson type cooler 10. The Joule-Thomson type cooler 10 comprises a casing 20 and a heat exchanger 30, housed inside the casing 20.

[0006] The casing 20, also designated by the term “cold finger”, comprises a contact wall 200 comprising an external surface 202, capable of receiving and / or being in contact with an element to be cooled 40, such as an infrared detector and / or an electronic component.

[0007] The heat exchanger 30 of cooler 10 comprises: - a hollow main body 310 extending along an axis Z of a reference XYZ between a head 311 and an end wall 312, together closing an interior space of the main body 310; the end wall 312 being arranged opposite the external surface 202 of the casing 20, and at least one gas pipe 32 surrounding the main body 310 in a helical manner.

[0008] The envelope 20 contains a volume divided into an expansion zone 210 and a heat exchange zone 212 according to which: - the expansion zone 210 extends, along the Z axis, between the contact wall 202 of the casing 20 and the end wall 312 of the main body 310 of the heat exchanger 30, and - the heat exchange zone 212 extends, along the Z axis, between the end wall 312 of the main body 310 and the head 311 of the heat exchanger 30; the heat exchange zone 210 being open to the outside by an opening 214 formed between the casing 20 and the head 311.

[0009] The heat exchanger 30 is arranged inside the casing 20 so that the head 311 is at least partly separated from a peripheral wall 204 of the casing 20, in order to define the opening 214 formed between the casing 20 and the head 311.

[0010] The gas pipe 32 of the heat exchanger 30 comprises a tube 320, with a longitudinal center O and extending longitudinally between: - an inlet 326, passing through the head 311 of the heat exchanger 30, capable of being connected to an external source of high-pressure compressed gas (not shown), and - an outlet 328, opening into the expansion zone 210 of the envelope 20.

[0011] As shown in Figures 2A and 2B, the tube 320 of the gas line 32 includes an outer surface 321 and fins 330 extending radially from the outer surface 321 and perpendicularly around the tube 320, respectively.

[0012] The gas pipe 32 is wound around the main body 310 of the heat exchanger 30, so that the tube 320 is wound around the main body 310 at a pitch “p” along the Z axis.

[0013] The operation of the Joule-Thomson type cooler 10 includes the following steps: - opening of a valve upstream of the inlet 326 of the tube 320, during which a high-pressure gas HP undergoes a first phase of expansion, and then is admitted, once expanded, into the tube 320 via the inlet 326; - circulation of the gas in the tube 320 to the outlet 328, during which the gas undergoes a second expansion phase resulting in progressive cooling; - ejection of the gas into the expansion zone 210 of the casing 20, during which the gas undergoes a third expansion phase also resulting in progressive cooling, so that, at the outlet of the expansion zone 210, the gas is a low-pressure LP gas; - circulation of the low-pressure gas LP in the heat exchange zone 212 up to the opening 214, during which the low-pressure gas LP cools the tube 320 and therefore the gas circulating in the tube 320; and - evacuation of low-pressure LP gas to the outside, in particular into the ambient atmosphere, through opening 214.

[0014] During the steps of circulation of the high-pressure gas HP, of the gas circulating in the tube 320, also designated by “gas of the gas line 32”, and of the low-pressure gas LP, the presence of fins 330 makes it possible to increase a heat exchange surface between the low-pressure gas LP, contained in the heat exchange zone 212 of the casing 20, and the gas of the gas line 32, hotter than the low-pressure gas LP, to improve the cooling of the gas of the gas line 32.

[0015] In fact, the performances of the Joule-Thomson type cooler 10 with such geometry are proportional: - the expansion capacities of high-pressure gas HP and gas from gas line 32, - to the heat exchange capacities between the low-pressure LP gas and the gas from gas line 32.

[0016] Furthermore, the performance of the cooler 10 is inversely proportional to the amount of thermal energy transmitted between a hot environment in contact with the head 311 and the outlet 328 of the tube 320 of the gas line 32.

[0017] Generally, the gas pipe 32 of such a heat exchanger 30 is made of a metallic material. The methods for manufacturing metallic gas pipes 32 are well known and mastered. However, they include different manufacturing steps increasing the manufacturing cost of the heat exchanger 30.

[0018] Furthermore, the thermal conductivity of metallic materials being significantly high, an amount of thermal energy transmitted longitudinally along the tube 320 wound helically between the inlet 326, close to the valve, and the outlet 328 of the tube 320 is not minimized, reducing the performance of such a cooler 10 of the Joule-Thomson type.

[0019] Since the thermal conductivity of ceramic is lower than that of metal, it was therefore considered to use ceramic for the manufacture of Joule-Thomson coolers and more particularly for the manufacture of heat exchangers 30.

[0020] However, the manufacturing of the gas pipe 32 of the heat exchanger 30 by an additive manufacturing process with a ceramic material is complex.

[0021] Indeed, the various manufacturing constraints associated with 3D (three-dimensional) ceramic printing techniques, such as a minimum wall thickness and a minimum draft angle, do not allow the manufacturing of a helical gas pipe 32 such as those integrated in conventional heat exchangers 30.

[0022] In addition, the use of a ceramic material to manufacture the tube 320 of the gas line reduces the heat exchange capacities between the cold low-pressure LP gas and the gas in the gas line 32 and would alter the performance of the Joule-Thomson cooler 10. SUMMARY OF THE INVENTION

[0023] The invention provides a solution to the problems mentioned above by proposing a Joule-Thomson type cooler heat exchanger having a particular architecture and construction.

[0024] A first aspect of the invention relates to a Joule-Thomson type cooler heat exchanger comprising a main body and at least one gas pipe surrounding the main body, in particular in a helical manner, the gas pipe being made of a material composed of ceramic and metal.

[0025] The heat exchanger according to the first aspect of the invention makes it possible, thanks to the use of a material composed of ceramic and metal, to minimize a transfer of thermal energy along the gas line while maintaining good heat exchange capacities of the gas line.

[0026] According to a first embodiment of the invention, the gas pipe comprises a tube comprising at least one high-pressure channel and at least one low-pressure channel, extending in particular along the entire length of the tube.

[0027] In such a case, the heat exchanges between the gas in the low-pressure channel and the gas in the high-pressure channel are carried out by conduction directly inside the gas pipe tube. The proximity between the low-pressure channel and the high-pressure channel improves the heat exchanges and therefore the cooling of the gas contained in the high-pressure channel.

[0028] In particular, according to the first embodiment, the tube of the gas line has an overall high-pressure channel volume less than an overall low-pressure channel volume of the tube.

[0029] Such a feature makes it possible to optimize the cooling of the gas contained in the high-pressure channel by the gas contained in the low-pressure channel, the latter having a larger volume in the gas line tube.

[0030] By total volume of high-pressure channel or total volume of low-pressure channel is meant the total volume of one or both high-pressure or low-pressure channels respectively. In other words, the tube comprises a section in which the section of the high-pressure channel or the sum of the sections of the high-pressure channels is less than the section of the low-pressure channel or the sum of the sections of the low-pressure channels of the tube.

[0031] Furthermore, according to the first embodiment, the tube of the gas pipe has a longitudinal center O, in particular of helical shape. In such a configuration, the high-pressure channel has a longitudinal center O and the low-pressure channel is distributed around the high-pressure channel.

[0032] Alternatively, the low-pressure channel has a longitudinal center O and the high-pressure channel is distributed around the low-pressure channel

[0033] Such a feature allows to improve the homogeneity of cooling of the gas circulating in the high-pressure channel.

[0034] According to an example of this first embodiment, the tube of the gas line comprises a single high-pressure channel. According to another variant of the first embodiment, the tube comprises several high-pressure channels distributed angularly around the longitudinal center O of the tube, with the low-pressure channels or around a single low-pressure channel.

[0035] According to the first embodiment, the high-pressure channel and the low-pressure channel of the gas line tube are sealed from each other.

[0036] According to a variant of the heat exchanger according to the first embodiment, the heat exchanger comprises an internal gas pipe directly wound around the main body and an external gas pipe wound around the internal gas pipe. Such an arrangement makes it possible to accelerate the cooling process of the heat exchanger.

[0037] According to a second embodiment of the invention, the gas pipe comprises a tube having an external surface and fins extending longitudinally from an external surface of the tube along the entire length of the tube.

[0038] In such a case, the heat exchanges between the gas contained outside the gas pipe and the gas contained inside the gas pipe of the high-pressure channel are carried out by conduction through the wall of the gas pipe tube.

[0039] The presence of longitudinal fins increases the heat exchange surface of the gas pipe and thus improves the cooling of the gas contained in the gas pipe tube.

[0040] The fact that the fins extend longitudinally only over half the circumference of the tube makes it possible to reduce the size of the gas pipe, without deteriorating the quality of the heat exchanges, compared to the presence of fins extending radially according to the prior art.

[0041] Advantageously, according to the second embodiment, the external surface is divided into two semi-circular portions, a first semi-circular portion of which is arranged opposite the main body of the heat exchanger and a second semi-circular portion is opposite the first circumferential portion.

[0042] According to the second embodiment, the longitudinal fins of the gas pipe extend from the second semi-circular portion.

[0043] Such a feature helps to reduce the bulk of the gas pipe. In addition, it helps to reduce the number of fins in the gas pipe while maintaining a large heat exchange surface area of ​​the gas pipe.

[0044] Preferably, according to the second embodiment, the fins of the gas pipe are parallel to each other. Such a characteristic makes it possible to simplify the manufacture of the gas pipe and to minimize its size.

[0045] A second aspect of the invention relates to a Joule-Thomson type cooler comprising a heat exchanger according to the first aspect of the invention, and a casing in which the heat exchanger is housed.

[0046] In addition, the casing may comprise a contact wall having an external surface capable of receiving an element to be cooled.

[0047] Furthermore, according to the second aspect of the invention, the casing comprises a sealing wall extending from the contact wall to the heat exchanger.

[0048] More particularly, the sealing wall forms: a cooling chamber extending between the contact wall of the casing and an end wall of the main body of the heat exchanger.

[0049] Optionally, the sealing wall can also be used to form a vacuum zone extending between the casing and the gas pipe.

[0050] Such a geometry of the Joule-Thomson type cooler makes it possible, with an exchanger according to the first embodiment, in particular by the presence of a vacuum zone, to thermally insulate the gas pipe and thus to minimize the quantity of thermal energy transmitted inside the gas pipe.

[0051] A third aspect of the invention relates to a method of manufacturing a heat exchanger according to the first aspect of the invention according to which it comprises at least one step of manufacturing the gas pipe comprising at least: - a step of forming the gas pipe by extrusion, and - a step of winding the gas pipe, in particular in a helical manner.

[0052] Such a manufacturing process, thanks to the implementation of the material composed of ceramic and metal, by extrusion, allows the gas pipe to be formed in a single manufacturing step.

[0053] In particular, according to a first variant of the third aspect of the invention, the step of forming and the step of winding the gas pipe are carried out simultaneously by a movable extrusion nozzle rotating around the main body of the heat exchanger.

[0054] In addition, the step of forming and the step of winding the gas pipe can be carried out simultaneously with a step of rotating the tube.

[0055] According to a second variant of the third aspect of the invention, the step of winding the gas pipe is carried out after the step of forming the gas pipe.

[0056] A fourth aspect of the invention relates to a Joule-Thomson type cooler heat exchanger comprising a main body and a gas pipe wound, in particular helically, around the main body. The gas pipe comprises a tube in which at least one high-pressure channel and at least one low-pressure channel are formed, each extending along the entire length of the tube.

[0057] A fifth aspect of the invention relates to a Joule-Thomson type cooler heat exchanger comprising a main body and a gas pipe wound, in particular helically, around the main body. The gas pipe comprises a longitudinal center tube O having an external surface surrounding at least one high-pressure channel and fins extending longitudinally from the external surface of the tube along the entire length of the tube.

[0058] Advantageously, according to the fourth aspect of the invention or the fifth aspect of the invention, the gas pipe is made of a metallic material.

[0059] Advantageously, according to the fifth aspect of the invention, the external surface is divided into two equal semi-circular portions, including a first semi-circular portion arranged opposite the main body and a second semi-circular portion opposite the first semi-circular portion, and each of the longitudinal fins of the gas pipe extending from the second semi-circular portion.

[0060] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0061] Of course, the different characteristics, variants and / or embodiments of the present invention can be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other. BRIEF DESCRIPTION OF THE FIGURES

[0062] The present invention will be better understood and other advantages and characteristics of the invention will become apparent upon reading the detailed description which follows, comprising embodiments given for illustrative purposes with reference to the appended figures, presented as non-limiting examples, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which: - Figure 1 is a schematic sectional representation of a Joule-Thomson cooler comprising a casing and a heat exchanger equipped with a gas pipe according to the state of the art; - Figure 2A is a partial schematic cross-sectional representation of the gas pipe of Figure 1; - Figure 2B is a partial sectional view along section plane BB of the gas pipe of Figure 2A; - Figure 3 is a schematic sectional representation of an embodiment of a Joule-Thomson type cooler according to the invention; - Figure 4 is a schematic sectional representation of an alternative embodiment of a Joule-Thomson type cooler according to the invention; - Figure 5A is a partial schematic representation in section of a first variant of a first embodiment of the gas pipe of Figure 4; - Figure 5B is a partial sectional view along a section plane BB of the gas pipe of Figure 5A; - Figure 6A is a partial schematic representation in section of a second variant of the first embodiment of the gas pipe of Figure 4; - Figure 6B is a partial sectional view along a section plane BB of the gas pipe of Figure 6A; - Figure 7A is a partial schematic sectional representation of a third variant of the first embodiment of the gas pipe of Figure 4; - Figure 7B is a partial sectional view along a section plane BB of the gas pipe of Figure 7A; - Figure 8A is a partial schematic sectional representation of a fourth variant of the first embodiment of the gas pipe of Figure 4; - Figure 8B is a partial sectional view along a section plane BB of the gas pipe of Figure 8A; - Figure 9A is a partial schematic cross-sectional representation of a second embodiment of the gas pipe of Figure 4; and - Figure 9B is a partial sectional view along a section plane BB of the gas pipe of Figure 9A. DETAILED DESCRIPTION

[0063] An exemplary embodiment of a Joule-Thomson type cooler comprising a heat exchanger according to the invention is described in detail below, with reference to the attached drawings. The exemplary embodiment presented illustrates the characteristics and advantages of the invention.

[0064] It should be noted that, in the figures, unless otherwise specified, the same structural and / or functional element common to the different embodiments appearing in different figures has a single reference. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0065] For an understanding of the invention, an orthonormal reference frame XYZ indicated in the figures is defined whose axes X and Y extend in a horizontal plane and the axis Z extends in a vertical plane, following the orientation in the figures.

[0066] In particular, a head towards an end wall of a heat exchanger can be oriented along the Z axis of the XYZ coordinate system.

[0067] Figure 3 represents a cooler 10 of the Joule-Thomson type according to a first embodiment of the invention comprising a casing 20 and a heat exchanger 30 housed inside the casing 20.

[0068] The envelope 20, also referred to as the “cold finger”, comprises: - a contact wall 200 comprising an external surface 202, capable of receiving an element to be cooled 40, such as an infrared detector and / or electronic component, and - a peripheral wall 204 extending along the Z axis.

[0069] The casing 20 contains a volume divided into a cooling chamber 220 and a vacuum zone 222 separated from each other by a sealing wall 216 extending from the contact wall 200 of the casing 20.

[0070] The cooling chamber 220 extends along the Z axis between the contact wall 202 of the casing 20 and the end wall 312 of the main body 310 of the heat exchanger 30 and is surrounded by the sealing wall 216 of the casing 20 along the X and Y axes.

[0071] The vacuum zone 222 extends along the Z axis between the contact wall 200 of the casing 20 and the head 311 of the heat exchanger 30 and is between the sealing wall 216 and the peripheral wall 204 of the casing 20 along the X and Y axes.

[0072] The sealing wall 216 is defined and arranged in the Joule-Thomson type cooler 10 such that the cooling chamber 220 and the vacuum zone 222 are physically separated. Thus, no gas communication can take place from the cooling chamber 220 to the vacuum zone 222, and vice versa.

[0073] The presence of a vacuum zone 222 provides thermal insulation around the gas pipe 32.

[0074] The heat exchanger 30 of cooler 10 comprises: - a hollow main body 310 extending along the Z axis of the XYZ reference frame, and - a gas pipe 32 surrounding the body 310, in particular in a helical manner.

[0075] In addition, the main body 310 of the heat exchanger 30 comprises a head 311 and an end wall 312 respectively arranged at an axial end of the main body 310. The main body 310 is configured to close an interior space of the main body 310.

[0076] The heat exchanger 30 is arranged inside the casing 20 so that the head 311 bears against a peripheral wall 204 of the casing 20. Furthermore, the heat exchanger 30 can be arranged inside the casing 20 so that the end wall 312 faces the external surface 202 of the contact wall 200 of the casing 20.

[0077] The gas pipe 32 of the heat exchanger 30 comprises a tube 320 with a longitudinal center O comprising an outer surface 321 and extending longitudinally between: - an inlet 326, passing through the head 311 of the heat exchanger 30, capable of being connected to an external source of high-pressure compressed gas (not shown), and - an outlet 328, opening into the cooling chamber 220 of the casing 20.

[0078] The gas pipe 32 is wound around the main body 310 of the heat exchanger 30, so that the tube 320 is wound around the main body 310 at a pitch “p” along the Z axis.

[0079] Figure 4 is a schematic sectional representation of an alternative embodiment of the Joule-Thomson type cooler 10 comprising the heat exchanger 30 according to the invention.

[0080] According to an alternative embodiment of the heat exchanger 30 as shown in FIG. 4, the heat exchanger 30 comprises an internal gas pipe 32A directly wound around the main body 310 and an external gas pipe 32B wound around the internal gas pipe 32A.

[0081] Thus, the internal gas line 32A of the heat exchanger 30 comprises an internal tube 320A comprising an outer surface and extending longitudinally between: - an internal inlet 326A, passing through the head 311 of the heat exchanger 30, capable of being connected to an external source of high-pressure compressed gas (not shown), and - an internal outlet 328A, opening into the cooling chamber 220 of the casing 20.

[0082] Similarly, the external gas line 32B of the heat exchanger 30 comprises an external tube 320B comprising an outer surface and extending along the longitudinal center O and longitudinally between: - an external inlet 326B, passing through the head 311 of the heat exchanger 30, capable of being connected to an external source of high-pressure compressed gas (not shown), and - an external outlet 328B, opening into the cooling chamber 220 of the casing 20.

[0083] The internal gas line 32A is wound around the main body 310 of the heat exchanger 30, so that the internal tube 320A is wound around the main body 310 at a pitch “p” along the Z axis.

[0084] Furthermore, the outer gas line 32A is wound around the inner gas line 32A, so that the outer tube 320B is wound around the inner tube 320A at a pitch "p" along the Z axis.

[0085] As shown in Figure 4, the heat exchanger 30 may comprise a sheath 314 extending from the end wall 312 and into which each outlet 328A, 328B of the internal 326A and external 326B pipes opens.

[0086] According to the first embodiment of the invention, the tube 320 of the gas pipe 32 comprises at least one high-pressure channel 322 and at least one low-pressure channel 324, in particular extending respectively along the entire length of the tube 320.

[0087] The high-pressure channels 322 and the low-pressure channels 324 are sealed from each other by inter-channel walls 323.

[0088] The tube 320 may have a section according to which the sum of the sections of the high-pressure channels 322 is less than the sum of the sections of the low-pressure channels 324 of the tube 320.

[0089] The outer surface 321 of the tube 320 of the gas pipe 32 is divided into two semicircles including: - a first semi-circular portion 321 A is arranged opposite the main body 310 of the heat exchanger 30, and - a second semi-circular portion 321 B is arranged opposite the vacuum zone 222 of the envelope 20.

[0090] The presence of high-pressure channels 322 and low-pressure channels 324 in the tube 320 of the gas line 32 makes it possible to carry out heat exchanges between the low-pressure gas LP of the low-pressure channel 324 and the gas of the high-pressure channel 322 by conduction directly inside the tube 320 of the gas line 32. The proximity between the low-pressure channel 324 and the high-pressure channel 322 makes it possible to improve the heat exchanges and therefore the cooling of the gas contained in the high-pressure channel 322.

[0091] In the first embodiment, the gas pipe 32 can be produced according to different variants described below.

[0092] Figures 5A and 5B are respectively a partial schematic representation in section of a first variant of a first embodiment of the gas pipe of Figure 4 and a partial sectional view along a section plane B-B of Figure 5A;

[0093] According to the first variant of the gas pipe 32 as shown in Figures 5A and 5B, the tube 320 comprises: - a single circular high-pressure channel 322 with longitudinal center O of the tube 320 of helical shape, and - two low-pressure channels 324 distributed around the high-pressure channel 322.

[0094] Optionally, each low-pressure channel 324 has a section in the shape of an arc of a circle. In particular, the low-pressure channels 324 are arranged symmetrically on either side of the high-pressure channel 322.

[0095] Figures 6A and 6b are respectively a partial schematic representation in section of a second variant of the first embodiment of the gas pipe of Figure 4 and a partial sectional view along a section plane B-B of the gas pipe of Figure 6A.

[0096] According to the second variant of the gas pipe 32 as shown in Figures 6A and 6B, the tube 320 comprises: - a single high-pressure channel 322, notably circular, with longitudinal center O of the tube 320, and - four low-pressure channels 324, in particular circular and specifically of the same diameter, distributed, in particular regularly, around the high-pressure channel 322.

[0097] Figures 7A and 7B are respectively a partial schematic representation in section of a third variant of the first embodiment of the gas pipe of Figure 4 and a partial sectional view along a section plane B-B of the gas pipe of Figure 7A.

[0098] According to the third variant of the gas pipe 32 as shown in Figures 7A and 7B, the tube 320 comprises: - a single high-pressure channel 322, in particular circular, with longitudinal center O of the tube 320, and - six low-pressure channels 324, in particular circular and specifically of the same diameter, distributed, in particular regularly, around the high-pressure channel 322.

[0099] Figures 8A is a partial schematic sectional representation of a fourth variant of the first embodiment of the gas pipe of Figure 4 and a partial sectional view along a section plane BB of the gas pipe of Figure 8A.

[0100] According to the fourth variant of the gas pipe 32 as shown in Figures 8A and 8B, the tube 320 comprises: - a first high-pressure channel 322, in particular circular, with longitudinal center O of the tube 320, - four low-pressure channels 324, in particular circular and specifically of the same diameter, distributed around the high-pressure channel 322, and - four second high-pressure channels 322', in particular circular channels of the same diameter, each distributed between two low-pressure channels 324.

[0101] According to an alternative of the fourth variant of the gas pipe 32, the diameter of each low-pressure channel 324 is greater than the diameter of each high-pressure channel 322.

[0102] The operation of the Joule-Thomson 10 type cooler according to the first embodiment comprises the following steps: - an opening step, during which a valve upstream of the inlet 326, respectively the internal inlet 326A and the external inlet 326B, of the tube 320, respectively the internal tube 320A and the external tube 320B, of the gas pipe 32 of the heat exchanger 30 is opened during which the high-pressure gas HP undergoes a first expansion phase, - a gas admission step, during which the gas, wholly or partly expanded, is admitted into each high-pressure channel 322 of the tube 320, respectively of the inner tube 320A and of the outer tube 320B, of the gas pipe 32 via the inlet 326, respectively the inner inlet 326A and the outer inlet 326B, - a gas circulation step, during which the gas circulates in each high-pressure channel 322 of the tube 320, respectively of the inner tube 320A and of the outer tube 320B, up to the outlet 328, respectively the inner outlet 328A and the outer outlet 328B, during which the gas undergoes a second expansion phase resulting in progressive cooling, - a gas ejection step, during which the gas is ejected through the outlet 328, respectively the internal outlet 328A and the external outlet 328B, into the cooling chamber 220 of the casing 20 so that, at the outlet 328, respectively the internal outlet 328A and the external outlet 328B, the gas undergoes a final expansion phase and becomes a cold low-pressure gas LP, - a LP gas admission step, during which the low-pressure LP gas is admitted into each low-pressure channel 324 of the tube 320 of the gas pipe 32 via the outlet 328, respectively the internal outlet 328A and the external outlet 328B, - a LP gas circulation step, during which the LP low-pressure gas circulates to the inlet 326, respectively the internal inlet 326A and the external inlet 326B, during which the LP low-pressure gas of each low-pressure channel 324 exchanges thermal energy with the gas circulating in each high-pressure channel 322 to cool it, and - an evacuation of the LP gas, during which the low-pressure LP gas from the Joule-Thomson 10 type cooler is evacuated, in this case into the ambient atmosphere downstream of the inlet 326, respectively the internal inlet 326A and the external inlet 326B.

[0103] Figure 9A is a partial schematic sectional representation of a second embodiment of the gas pipe of Figure 4 and a partial sectional view along a section plane BB of the gas pipe of Figure 9A.

[0104] According to a second embodiment of the invention, the Joule-Thomson 10 type cooler may comprise: - an envelope 20 identical to that of the Joule-Thomson 10 type cooler according to the state of the art, as shown in figure 1, or - an envelope 20 as shown in Figure 4 and a gas pipe 32 as shown in Figures 9A and 9B.

[0105] According to the second embodiment, the tube 320 of the gas pipe 32 comprises only a high-pressure channel 322 and longitudinal fins 330 extending respectively from the external surface 321 of the tube 320. The fins 330 are arranged along the length of the tube 320.

[0106] More particularly, the fins 330 each extend longitudinally and parallel to the longitudinal center O of the second semi-circular portion 321 B of the outer surface 321 of the tube 320.

[0107] Such an arrangement of the fins 330 makes it possible to minimize, compared to a heat exchanger equipped with a gas pipe and fins according to the state of the art, the pitch “p” of the tube 320, that is to say the diameter of the tube 320, by obtaining longitudinal portions of the external surface 321 contiguous in contact with each other.

[0108] Such an arrangement makes it possible to obtain a longer gas pipe 32 compared to a gas pipe 32 according to the prior art comprising radial fins 330.

[0109] The operation of the Joule-Thomson 10 type cooler according to the second embodiment is substantially identical to the operation of the Joule-Thomson 10 type cooler of the prior art as described above, except for the fact that the low-pressure gas LP circulates along a space formed between the longitudinal fins 330, thus licking the longitudinal fins 330 and the second circumferential portion 321 B of the external surface 321 of the tube 320 between two longitudinal fins 330.

[0110] In particular, in the case of an envelope 20 according to FIG. 4, a space formed between two fins 330 forms a closed helical channel with the sealing wall 216 in which the low-pressure gas LP circulates, thus allowing better cooling of the gas circulating in the high-pressure channel 322.

[0111] A method of manufacturing a heat exchanger 30 according to the invention comprises a step of manufacturing the gas pipe 32 comprising at least: - a forming step, during which the gas pipe 32 is formed by extruding a material composed of metal and ceramic, and - a winding step, during which the gas pipe 32 is wound, in particular helically, around the main body 310 of the heat exchanger 30.

[0112] According to a first variant of the manufacturing method, the step of forming and the step of winding the gas pipe 32 are carried out simultaneously by a movable extrusion nozzle rotating around the main body 310 of the heat exchanger 30.

[0113] Alternatively or in addition, the forming step and the winding step are carried out simultaneously with a step of rotating the tube 320. In this way, it is possible to increase the length of the low-pressure channels 324 and / or the high-pressure channels 322 arranged at the periphery of the tube 320, thereby maximizing the heat transfer between the gas circulating in the low-pressure channels 324 and the gas circulating in the high-pressure channels 322.

[0114] According to a second variant of the manufacturing method, the step of winding the gas pipe 32 is carried out after the step of forming the gas pipe 32 by shaping the gas pipe 32 around the main body 310. In particular, the winding step can be carried out hot.

[0115] The step of forming the gas pipe 32 according to the first embodiment consists of forming the tube 320, the high-pressure channels 322, the low-pressure channels 324 and the inter-channel walls 323.

[0116] The step of forming the gas pipe 32 according to the second embodiment consists of forming the tube 320 and the fins 330.

[0117] A heat exchanger 30 according to the invention makes it possible, thanks to the use of a material composed of metal and ceramic for the manufacture of the gas pipe 32, respectively the internal gas pipe 32A and the external gas pipe 32B, to minimize the quantity of thermal energy transmitted between the inlet 326, respectively the internal inlet 326A and the external inlet 326B, and the outlet 328, respectively the internal outlet 328A and the external outlet 328B, of the gas pipe 32, respectively the internal gas pipe 32A and the external gas pipe 32B, while maintaining good heat exchange capacities of the gas pipe between the cold low-pressure LP gas and the high-pressure HP gas.

[0118] In addition, the use of such a material makes it possible to simplify the manufacturing process by reducing the number of manufacturing steps and thus to reduce the manufacturing cost of the heat exchanger 30 according to the invention.

[0119] In the detailed presentation of the invention given above, the terms used should not be considered as limiting the invention to the embodiments set forth in the description just given, but should be interpreted to include all equivalents the prediction of which is within the reach of those skilled in the art by applying their general knowledge to the implementation of the teaching just disclosed to them.

[0120] Obviously, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that may be envisaged by those skilled in the art within the framework of the present invention and in particular all combinations of the different operating modes described above, which can be taken separately or in combination.

Claims

CLAIMS

1. Heat exchanger (30) of a cooler (10) of the Joule-Thomson type comprising a main body (310), and at least one gas pipe (32, 32A, 32B) surrounding the main body (310), in particular in a helical manner; characterized in that the gas pipe (32, 32A, 32B) is made of a material composed of ceramic and metal.

2. Heat exchanger (30) according to claim 1, characterized in that the gas pipe (32, 32A, 32B) comprises a tube (320) comprising at least one high-pressure channel (322) and at least one low-pressure channel (324), the high-pressure channel (322) and / or the low-pressure channel (324) extending in particular along the entire length of the tube (320).

3. Heat exchanger (30) according to claim 2, characterized in that the tube (320) has an overall volume of high-pressure channel (322) less than an overall volume of low-pressure channel (324).

4. Heat exchanger (30) according to claim 2 or 3, characterized in that the tube (320) has a longitudinal center O, in particular of helical shape, and in that: - the high-pressure channel (322) has a longitudinal center O, and - the low-pressure channel (324) is distributed around the high-pressure channel (322).

5. Heat exchanger (30) according to claim 2 or 3, characterized in that the tube (320) has a longitudinal center O, in particular of helical shape, and in that: - the low-pressure channel (324) has a longitudinal center O, and - the high-pressure channel (322) is distributed around the low-pressure channel (324).

6. Heat exchanger (30) according to claim 1, characterized in that the gas pipe (32) comprises: - a tube (320) having an external surface (321), and fins (330) extending longitudinally from an external surface (321) of the tube (320), in particular along the entire length of the tube (320).

7. Heat exchanger (30) according to claim 6, characterized in that: - the external surface (321) of the tube (320) comprises a first semi-circular portion (321 A), arranged opposite the main body (310) of the heat exchanger (30), and a second semi-circular portion (321 B), - and in that the fins (330) extend from the second semi-circular portion (321 B).

8. Joule-Thomson type cooler (10) comprising: - a heat exchanger (30) according to any one of the preceding claims, and - an envelope (20), in which the heat exchanger (30) is housed.

9. Joule-Thomson cooler (10) according to claim 8, characterized in that the casing (20) comprises a contact wall (200) comprising an external surface (202), capable of receiving an element to be cooled (40).

10. Joule-Thomson cooler according to claim 9, characterized in that the casing (20) comprises a sealing wall (216) extending from the contact wall (200) to the heat exchanger (30).

11. Joule-Thomson cooler according to claim 10, characterized in that the sealing wall (216) forms: - a cooling chamber (220) extending between the contact wall (200) of the casing (20) and an end wall (312) of the main body (310) of the heat exchanger (30), and - optionally, a vacuum zone (222) extending between the casing (20) and the gas pipe (32, 32A, 32B).

12. A method of manufacturing a heat exchanger (30) according to any one of claims 1 to 7, characterized in that it comprises at least one step of manufacturing the gas pipe (32, 32A, 32B) comprising at least: - a forming step, during which the gas pipe (32, 32A, 32B) is formed by extrusion, and - a winding step, during which the gas pipe (32) is wound, in particular in a helical manner.

13. A manufacturing method according to claim 12, characterized in that the step of forming and the step of winding the gas pipe (32) are carried out simultaneously by a movable extrusion nozzle rotating around the main body (310) of the heat exchanger (30).

14. Manufacturing method according to claim 12 or 13 in combination with claim 2, characterized in that the step of forming and the step of winding the gas pipe (32) are carried out simultaneously with a step of rotating the tube (320).

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