FR3065064A1 - DEVICE AND METHOD FOR COOLING A CRYOGENIC FLUID FLOW - Google Patents

Abstract

Apparatus for cooling a cryogenic fluid flow comprising a cryoreocooler (2) comprising a cold head (3) provided with an exchange surface (4), in heat exchange with a heat exchanger comprising a mass (5) of thermal conductive material, the mass (5) of conductive material being in heat exchange with the flow of fluid to be cooled, the cryogenic fluid circuit to be cooled comprising a pipe (6) for supplying a flow of fluid and a pipe ( 7) for recovering the heat exchanged fluid flow with the mass (5) of conductive material and in that the mass (5) of conductive material is housed in a sealed casing (12) comprising a fluid inlet connected to the pipe (6) supply and a fluid outlet connected to the pipe (7) for recovery, the mass (5) of conductive material consisting of adjacent sections (15) forming fins which each extend from the surface (4). ) of exchanged e of the cold head (3) between a first upper end adjacent to the exchange surface (4) of the cold head (3) and an opposite second lower end

Description

Holder (s): AIR LIQUIDE, ANONYMOUS COMPANY FOR THE STUDY AND EXPLOITATION OF GEORGES CLAUDE PROCESSES Société anonyme.

Extension request (s)

Agent (s): AIR LIQUIDE.

DEVICE AND METHOD FOR COOLING A FLOW OF CRYOGENIC FLUID.

FR 3 065 064 - A1 (57)

Device for cooling a flow of cryogenic fluid comprising a cryocooler (2) comprising a cold head (3) provided with an exchange surface (4), in heat exchange with a heat exchanger comprising a mass (5) of thermal conductive material, the mass (5) of conductive material being in heat exchange with the flow of fluid to be cooled, the cryogenic fluid circuit to be cooled comprising a line (6) for supplying a flow of fluid and a line ( 7) for recovering the flow of fluid having thermally exchanged with the mass (5) of conductive material and in that the mass (5) of conductive material is housed in a sealed casing (12) comprising a fluid inlet connected to the pipe (6) supply and a fluid outlet connected to the recovery pipe (7), the mass (5) of conductive material consisting of adjacent sections (15) forming fins which each extend from the surface (4 ) exchange e of the cold head (3) between a first upper end adjacent to the surface (4) for exchanging the cold head (3) and a second opposite lower end

The invention relates to a device for cooling a cryogenic fluid.

The invention relates in particular to a heat exchange device (monophasic or multiphasic) with a cold source of the type having a planar surface.

The invention relates more particularly to a device for cooling a flow of cryogenic fluid, in particular for the condensation of a gas within a mixture of gases, the device comprising a cryo-cooler comprising a cold head provided with a exchange surface, the exchange surface of the cold head being in heat exchange with a heat exchanger comprising a mass of thermal conductive material, the mass of conductive material being in heat exchange with the flow of cryogenic fluid to be cooled.

The invention relates in particular to a device for cooling a cryogenic fluid composed of a gaseous or partly liquid mixture.

In particular, the invention may advantageously relate to the condensation of neon in a flow of a mixture of helium and neon in which the mixture is brought close to the triple point of the Neon (24.5 K).

This invention can be applied to any type of mixture for which it is desired to cool, or even condense, one or more constituents, by heat exchange with a flat cold surface. This invention has a large developed exchange surface in a small footprint.

The known solutions of cooling devices for producing such condensation, although satisfactory, are either expensive / complex or have insufficient efficiency.

An object of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

To this end, the device according to the invention, furthermore in accordance with the generic definition given in the preamble above, is essentially characterized in that the cryogenic fluid circuit to be cooled comprises a supply line of a fluid flow intended to thermally exchange with the mass of conductive material and a pipe for recovering the flow of fluid having thermally exchanged with the mass of conductive material and in that the mass of conductive material is housed in a sealed casing comprising an inlet for fluid connected to the supply line and a fluid outlet connected to the recovery line, the mass of conductive material consisting of adjacent sections forming fins which each extend from the exchange surface of the cold head between a first upper end adjacent to the exchange surface of the cold head and a second lower end o posed.

Furthermore, embodiments of the invention may include one or more of the following characteristics:

- the adjacent sections forming fins each extend in a direction perpendicular to the exchange surface of the cold head,

- the adjacent sections are separated by respective interstices which extend in the direction perpendicular to the exchange surface of the cold head,

- the successive interstices are connected consecutively to each other by fluid passages located alternately near the first upper end of the mass and then near the second lower end, so that the flow of fluid which enters the casing via the supply line must flow sequentially in a gap in one direction and then in the next gap by changing direction, that is to say that, in a first gap the fluid flow circulates in a direction perpendicular to the surface interchange and from the second lower end to the first upper end, then enters a second gap at the first upper end and flows through this second gap from the first upper end to the second lower end and so on until to the recovery line,

- the fluid circuit inside the casing connecting the fluid inlet to the fluid outlet forms a closed loop comprising two separate branches connecting the inlet to the outlet, the flow of fluid which enters the casing via the pipe supply flowing in the direction of the outlet orifice, subdividing into two portions circulating respectively in the two branches, that is to say that a first portion of the fluid circulates in a first branch by passing through a first assembly of corresponding interstices while the second portion of the fluid circulates in the second branch while passing through the other set of corresponding interstices,

- the fluid circuit inside the casing connecting the fluid inlet to the fluid outlet forms a closed loop comprising a single path and in that the flow of fluid which enters the casing via the supply line circulates in the direction of the outlet orifice forms a single flow circulating in a predetermined direction in the loop, that is to say that the flow passes sequentially through all the interstices before joining the outlet pipe,

the mass of conductive material has the general shape of a cylinder whose central longitudinal axis and the generatrices are perpendicular to the exchange surface of the cold head, the interstices being formed radially between the central longitudinal axis of the cylinder and its periphery,

- the adjacent sections are regularly distributed around and a central longitudinal axis perpendicular to the exchange surface,

- the supply line opens into the casing adjacent to the second lower end of the mass of conductive material,

the recovery pipe opens into the casing adjacent to the first upper end or adjacent to the second lower end of the mass of conductive material,

the mass of conductive material consists at least in part of a metallic material, in particular copper, a copper alloy, aluminum or an aluminum alloy,

the mass of conductive material is brought into contact with the exchange surface of the cold head, a layer of gilding and / or thermal grease and / or of a filler of thermal conductive material, being interposed between the mass of material conductor and the exchange surface of the cold head,

- the surfaces in contact with the mass of conductive material and the exchange surface of the cold head each include a gilding having a thickness of between 0.1 μm and 100 μm,

- the fluid inlet and outlet connected respectively with the supply and recovery pipes are arranged diametrically opposite on either side of the central longitudinal axis of the cylinder,

The invention also relates to a method of condensing neon in a gas mixture flow containing neon and helium in gaseous form in which the gas flow is cooled in a device according to any one of the characteristics below. -above or below at a temperature less than or equal to the condensation temperature of the neon.

The invention may also relate to any alternative device or process comprising any combination of the above or below characteristics.

Other particularities and advantages will appear on reading the description below, made with reference to the figures in which:

FIG. 1 represents a schematic and partial side view of a vertical section of an example of the structure and operation of a cooling device according to the invention,

FIGS. 2 and 3 represent views in transverse, schematic and partial sections, along lines AA and BB respectively of FIG. 1,

- Figure 4 shows a perspective view, schematic and partial illustrating a detail of the structure and operation of the device of Figure 1.

The cooling device 1 illustrated in the figures comprises a cryocooler 2 comprising a cold head 3 provided with a terminal exchange surface 4.

The exchange surface 4 of the cold head 3, for example forms a disc in heat exchange with a heat exchanger comprising a mass 5 of thermal conductive material.

The mass 5 of conductive material has for example a generally cylindrical shape whose end (upper face) is in contact with the terminal end 4 of the cold head 3.

For example, the mass 5 of conductive material consists at least in part of a metallic material, for example copper or aluminum or a copper or aluminum alloy.

Contact between the cold head 4 and the mass 5 can be achieved by mechanical tightening, for example by brazing (filler alloy based on tin or silver for example) or by welding. For example, as illustrated in FIGS. 2 and 3, the mass 5 of conductive material may include a plurality of bores 111 arranged around the center of the mass and provided for fixing screws on the cold head 3.

At least part of the rest of the body of the mass 5 of conductive material is in heat exchange (preferably by direct contact) with the flow of cryogenic fluid to be cooled.

The device 1 comprises a cryogenic fluid circuit to be cooled comprises a line 6 for supplying a flow of fluid intended to thermally exchange with the mass 5 of conductive material and a line 7 for recovery which collects the flow of fluid having thermally exchanged with the mass 5 of conductive material.

The mass 5 of conductive material is housed in a sealed casing 12. That is to say that the casing 12 delimits a volume in which the exchange (contact) takes place between the flow of fluid to be cooled and the mass 5 of material cooled by the cold head 4.

The casing 12 includes a fluid inlet connected to the supply line 6 and a fluid outlet connected to the recovery line 7.

The casing 12 can be hermetically closed around the mass 5 of conductive material by soldering, welding or mechanical tightening for example. The material constituting the casing 12 is not necessarily the same as that constituting the mass 5.

A central part 18 can be placed in a central bore 10 of the mass 5. This part 18 can be a block of material (an electrical resistance for example) mounted tightly in the bore 10, and whose function can be to cancel any passage or bypass for the fluid between the adjacent fin sections. The mounting of this part 18 can be carried out by shrinking, by cryogenic immersion of the central part 18 then insertion into the bore 10 of the support mass 5 maintained at room temperature for example during assembly.

The mass 5 of conductive material consists of adjacent sections 15 forming fins which each extend in a direction perpendicular to the exchange surface 4 of the cold head 3 between a first upper end adjacent to the exchange surface 4 the cold head 3 (above in FIG. 1) and a second opposite lower end (below in FIG. 1).

As a possible variant (not shown in the figures), the adjacent sections 15 forming fins each extend in a direction parallel to the exchange surface 4 of the cold head 3.

The adjacent sections 15 are separated by respective interstices 11 which extend in the direction perpendicular to the exchange surface 4 of the cold head 3. These interstices 11 form passages for the flow of fluid intended to thermally exchange with the mass 5.

As illustrated, the interstices 11 can be arranged radially around a central longitudinal axis perpendicular to the end surface of the cold head 4. These interstices 11 can be created by an industrial wire or laser cutting process for example.

These successive interstices 11 are connected consecutively to each other by passages 13 and 14 of fluid located alternately near the first upper end of the mass 5 and then near the second lower end. Thus, the flow of fluid which enters the casing 12 via the supply line 6 must flow sequentially in a gap 11 in one direction (for example from bottom to top in FIG. 1) then in the next gap 11 by changing direction (from top to bottom in Figure 1).

In other words, in a first gap 11, the flow of fluid circulates in a direction perpendicular to the exchange surface 4 and from the second lower end to the first upper end. Then, the flow enters via the passage or channel 14 into a second interstice 11 at the first upper end and flows in this second interstice 11 from the first upper end to the second lower end and so on to the pipe 7 recovery.

Figures 2 and 3 illustrate an exemplary embodiment: the interstices 11 (arranged radially around a central longitudinal axis of the mass 5) are connected sequentially to each other by passages located alternately at the top (cf. reference 14) then at the bottom (see reference 13) of the mass.

This is also illustrated schematically in Figure 4 where the flow 17 from the left goes up an interstice 11 then joins the adjacent interstice to the right via an upper passage 14 then descends into this second interstice then goes up into the next and ... Thus the passages 14, 13 constrain the flow to pass from one interstice 11 to another (in the plane perpendicular to the interstices) by changing direction (from top to bottom or from bottom to top) of circulation with each change of gap 11.

This structure creates meanders in both directions (vertical and transverse) which increase the heat exchange of the flux with the fins of the mass 5 of material.

As shown diagrammatically in FIG. 5, along a plane parallel to the cutting planes of FIGS. 3 and 4, the fluid circuit 17 inside the casing 12 connecting the fluid inlet (symbolized by the reference 6) to the outlet of fluid (symbolized by the reference 7) forms a closed loop comprising two distinct branches 16, 26 connecting the inlet 6 to the outlet 7. The flow of fluid which enters the casing via the supply line 6 flows in the direction of the outlet 7 by subdividing into two portions circulating respectively in the two branches 16, 26. That is to say that a first portion of the fluid circulates a first branch 16 passes through a first set of corresponding interstices 15 while the second portion of the fluid circulates in the second branch 26 while passing through the other set of corresponding interstices 15.

In the variant of FIG. 6, the fluid circuit 17 inside the casing 12 connecting the fluid inlet 6 to the fluid outlet 7 forms a closed loop comprising a single path. Thus, all the flow of fluid which enters the casing 12 via the supply line 6 flows in the direction of the outlet orifice 7 in a predetermined direction in the loop. That is to say that the flow passes sequentially through all the interstices 15 before joining the outlet pipe 7.

These arrangements make it possible to diffuse a flow (in particular two-phase) in a homogeneous manner in each channel / interstice 11.

According to an advantageous feature, the mass 5 of conductive material can be brought into contact with the exchange surface 4 of the cold head 3 by interposing a layer 8, 9 of a material significantly improving the contact resistance between 4 and 5 ( gilding by electrochemical deposition or fillers "fillers" of alloys of gold or indium for example and / or thermal grease) between the mass 5 of conductive material and the surface 4 of exchange of the cold head 3.

For example, the two surfaces in contact with the mass 5 of conductive material and the exchange surface 4 of the cold head 3 may each have a gilding having a thickness of between 0.1 μm and 100 μm. Of course, as a variant, a single layer of gilding can also be provided on one of the two faces.

This reduces the contact resistance with the cold surface. The efficiency of device 1 is improved. In addition, this also limits the risk of local corrosion / oxidation in the long term.

This structure makes it possible to obtain extremely high thermal conductivities in the case in particular of copper (strong increase in thermal conductivity for copper between 4K and 40K) or of aluminum, and thus to minimize the associated thermal resistances.

A bore or blind hole (not shown) can be provided to accommodate a temperature sensor.

The temperature sensor can be provided for regulating a heating member such as a heating resistor housed in a central bore 13 to finely regulate the temperature of the mass 5 and therefore control the cooling temperature.

Thus, while being simple and reliable in structure, the device has great efficiency, in particular for condensing neon contained in a stream of helium and neon.

Claims (15)

1. Device for cooling a flow of cryogenic fluid, in particular for the condensation of a gas within a mixture of gases, the device (1) comprising a cryo-cooler (2) comprising a cold head (3) provided with an exchange surface (4), the cold head exchange surface (4) (3) being in heat exchange with a heat exchanger comprising a mass (5) of thermal conductive material, the mass ( 5) of conductive material being in heat exchange with the flow of cryogenic fluid to be cooled, characterized in that the cryogenic fluid circuit to be cooled comprises a line (6) for supplying a flow of fluid intended to heat exchange with the mass (5) of conductive material and a pipe (7) for recovering the flow of fluid having thermally exchanged with the mass (5) of conductive material and in that the mass (5) of conductive material is housed in a casing (12 ) waterproof including one in fluid inlet connected to the supply line (6) and a fluid outlet connected to the recovery line (7), the mass (5) of conductive material consisting of adjacent sections (15) forming fins which each extend from the surface (4) for exchanging the cold head (3) between a first upper end adjacent to the surface (4) for exchanging the cold head (3) and a second opposite lower end. 2. Cooling device according to claim 1, characterized in that the adjacent sections (15) forming fins each extend in a direction perpendicular to the surface (4) for exchanging the cold head (3). 3. Device according to claim 2, characterized in that the adjacent sections (15) are separated by respective interstices (11) which extend in the direction perpendicular to the surface (4) for exchanging the cold head (3 ). 4. Device according to claim 3, characterized in that the successive interstices (11) are connected consecutively to each other by passages (14, 13) of fluid located alternately near the first upper end of the mass (5) then near the second lower end, so that the flow of fluid which enters the casing (12) via the supply line (6) must flow sequentially through a gap (11) in one direction then in the gap (11) following by changing direction, that is to say that, in a first gap (11) the fluid flow circulates in a direction perpendicular to the surface (4) of exchange and from the second lower end towards the first upper end, then enters (14) into a second interstice (11) at the first upper end and flows through this second interstice (11) from the first upper end to the second lower end higher and so on up the line (7) recovery. 5. Device any one of claims 3 to 4, characterized in that the circuit (17) of fluid inside the casing (12) connecting the fluid inlet to the fluid outlet forms a closed loop comprising two separate branches (16, 26) connecting the inlet to the outlet, and in that the flow of fluid which enters the casing (12) via the supply line (6) flows in the direction of the orifice (7) outlet by subdividing into two portions circulating respectively in the two branches (16, 26), that is to say that a first portion of the fluid circulates in a first branch (16) passing through a first set of corresponding interstices (15) while the second portion of the fluid circulates in the second branch (26) passing through the other set of corresponding interstices (15). 6. Device any one of claims 3 to 4, characterized in that the circuit (17) of fluid inside the casing (12) connecting the fluid inlet to the fluid outlet forms a closed loop comprising a single path and in that the flow of fluid which enters the casing (12) via the supply line (6) flows in the direction of the outlet orifice (7) forms a single flow circulating in a predetermined direction in the loop, that is to say that the flow passes sequentially through all the interstices (15) before joining the outlet pipe (7). 7. Device according to any one of claims 1 to 6, characterized in that the mass (5) of conductive material has a general shape of a cylinder whose central longitudinal axis and the generatrices are perpendicular to the surface (4 ) for exchanging the cold head (3) and in that the interstices (15) are formed radially between the central longitudinal axis of the cylinder and its periphery. 8. Device according to claim 7, characterized in that the adjacent sections (15) are regularly distributed around and of a central longitudinal axis perpendicular to the exchange surface (4). 9. Device according to any one of claims 1 to 8, characterized in that the supply pipe (6) opens into the casing (12) adjacent to the second lower end of the mass (5) of conductive material . 10. Device according to any one of claims 1 to 9, characterized in that the recovery pipe (7) opens into the casing (12) adjacent to the first upper end or adjacent to the second lower end of the mass (5) of conductive material. 11 .A device according to any one of claims 1 to 10, characterized in that the mass (5) of conductive material consists at least in part of a metallic material, in particular copper, a copper alloy, d aluminum or an aluminum alloy. 12. Device according to any one of claims 1 to 10, characterized in that the mass (5) of conductive material is brought into contact with the surface (4) for exchanging the cold head (3) and in that '' a layer (8, 9) of gilding and / or thermal grease and / or of a filler made of thermal conductive material, is interposed between the mass (5) of conductive material and the surface (4) for exchanging the cold head (3). 13. Device according to claim 11, characterized in that the surfaces in contact with the mass (5) of conductive material and the surface (4) for exchanging the cold head (3) each include a gilding having a thickness comprised between 0.1 pm and 100 pm. 14. Device according to any one of claims 1 to 12, characterized in that the fluid inlet and outlet respectively connected with the pipe (6) for supply and recovery (7) are arranged diametrically opposite from one side and across the central longitudinal axis of the cylinder. 15. A method of condensing neon within a gas mixture flow containing neon and helium in gaseous form in which the gas flow is cooled in a device according to any one of claims 1 to 13 to a temperature less than or equal to the temperature 5 of neon condensation. 1/2 Fl 6.3