Cooling apparatus

Abstract

A cooling apparatus having a closed cooling circuit for cooling objects to semi-cryogenic or cryogenic temperatures includes a compressor to compress a gaseous coolant, and from which the coolant exits in a compressed gaseous state, an after-cooler connected downstream from the compressor, whereby the coolant exits largely in gaseous form, a counterflow heat exchanger having a feed line and return line arranged in such a way that the compressed coolant is liquefied in the feed line as the relieved coolant flowing through the return line is being heated. A cooling head that is connected with the feed line and return line. A coolant can flow through the cooling head whereby the coolant evaporates. The cooling head is arranged in a vacuum chamber, which can be joined with a low-pressure source, and is joined by flexible connecting lines with the feed line and return line of the counterflow heat exchanger.

Claims

1. A cooling apparatus with a closed cooling circuit, said closed cooling circuit configured for cooling objects to semi-cryogenic or cryogenic temperatures of 230 K to 80 K, said closed cooling circuit for cooling objects to said semi-cryogenic or cryogenic temperatures according to the Joule Thomson cooling process, said cooling apparatus comprising a compressor for compressing a gaseous coolant supplied to the compressor in a gaseous state so as to obtain a compressed gaseous coolant, and said coolant exiting in a compressed gaseous state from said compressor, an after-cooler connected downstream from the compressor, from which the coolant exits largely in gaseous form, a counterflow heat exchanger (7) comprising a feed line and a return line, which are arranged in such a way that the compressed coolant is liquefied in the feed line as the relieved coolant flowing through the return line is being heated, a cooling head (11) that is connected with the feed line to receive the liquefied coolant from the feed line and connected with the return line and has the coolant flowing through said cooling head in which the liquefied coolant evaporates, a vacuum chamber (16), and a throttle (10), wherein the cooling head (11) is arranged in the vacuum chamber (16), which is adapted for joinder with a low-pressure source, and is joined by flexible connecting lines (13, 14) with the feed line and return line (8, 9) of the counterflow heat exchanger (7), the counterflow heat exchanger is situated outside of and not in the vacuum chamber in which the cooling head is arranged, and the counterflow heat exchanger is not arranged in any other vacuum chamber, the connecting lines (13, 14) have vacuum insulation (17), the vacuum insulation (17) having a hollow space, the vacuum chamber (16) having a lead-through for the connecting lines (13, 14), the vacuum chamber configured such that the hollow space of the vacuum insulation (17) for the connecting lines (13, 14) is joined with the interior space of the vacuum chamber (16), the cooling head (11) is connected to the feed line (8) of the counterflow heat exchanger (7) with the throttle (10) disposed between said feed line and the cooling head, and the vacuum chamber (16) and the vacuum insulation (17) for the connecting lines (13, 14) are directly joined together, and are configured for joinder with a shared low-pressure source.

2. The cooling apparatus according to claim 1, wherein the vacuum insulation (17) comprises a cladding tube (18) that envelops the connecting lines (13, 14), with the formation of an essentially annular hollow space, wherein the hollow space can be joined with a low-pressure source.

3. The cooling apparatus according to 2, wherein the cooling apparatus further comprises at least one spacer (19) is arranged in the hollow space between the connecting lines (13, 14) and the cladding tube (18).

4. The cooling apparatus according to claim 3, wherein the spacer (19) exhibits a corrugated outer and inner contour.

5. The cooling apparatus according to claim 2, wherein the vacuum chamber (16) includes a port (23) for connecting the shared low-pressure source.

6. The cooling apparatus according to claim 1, wherein the vacuum chamber (16) incorporates a tubular spacer (22), said spacer envelops the lead-through, and defines the distance between the cooling head (11) and an inner wall of the vacuum chamber (16), said spacer (22) having radial through holes (24).

7. The cooling apparatus according to claim 1, wherein the coolant comprises butane and/or isobutane and/or propane and/or propene and/or ethyne and/or ethane and/or ethene and/or methane and/or argon and/or nitrogen.

8. The cooling apparatus according to claim 1, wherein the coolant comprises a butane, isobutene, propane, propene, ethyne, ethane, ethane, methane, argon, or a combination of any thereof.

9. A cooling apparatus having a closed cooling circuit, said closed cooling circuit configured for cooling objects to semi-cryogenic or cryogenic temperatures of 230 K to 80 K, said closed cooling circuit for cooling objects to said semi-cryogenic or cryogenic temperatures according to the Joule Thomson cooling process, said cooling apparatus comprising a compressor for compressing a gaseous coolant supplied to the compressor in a gaseous state so as to obtain a compressed gaseous coolant, and said coolant exiting in a compressed gaseous state from said compressor; an after-cooler (5) connected downstream from the compressor, from which the coolant exits largely in gaseous form; a counterflow heat exchanger comprising a feed line and a return line, which are arranged in such a way that the compressed coolant is liquefied in the feed line as the relieved coolant flowing through the return line is being heated; a cooling head (11) that is connected with the feed line to receive the liquefied coolant from the feed line and connected with the return line and has the coolant flowing through said cooling head in which the liquefied coolant evaporates; a vacuum chamber (16), and a floor mounted device, wherein the cooling head (11) is arranged in the vacuum chamber, which is adapted for joinder with a low-pressure source, and is joined by flexible connecting lines (13, 14) with the feed line and return line (8, 9) of the counterflow heat exchanger (7), the counterflow heat exchanger (7) is situated outside of and not in the vacuum chamber (16) in which the cooling head is arranged, and the counterflow heat exchanger is not arranged in any other vacuum chamber, the connecting lines (13, 14) have vacuum insulation (17), the vacuum chamber (16) and the vacuum insulation (17) for the connecting lines (13, 14) are directly joined together, and are configured for joinder with a shared low-pressure source, and the compressor (1), after-cooler (5) and counterflow heat exchanger (7) are situated together in the floor-mounted device, the floor-mounted device further comprising a housing having a lead-through for the connecting lines (13, 14) that join the counterflow heat exchanger (7) with the vacuum chamber (16).

10. The cooling apparatus according to claim 9, wherein the cooling head (11) is connected to the feed line (8) of the counterflow heat exchanger (7) with a throttle (10) disposed between said feed line and the cooling head.

11. The cooling apparatus according to claim 10, wherein the connecting line (13) joining the feed line (8) of the counterflow heat exchanger (7) with the cooling head (11) forms the throttle (10).

12. The cooling apparatus according to claim 9, wherein the vacuum insulation (17) having a hollow space, the vacuum chamber (16) having a lead-through for the connecting lines (13, 14), the vacuum chamber configured such that the hollow space of the vacuum insulation (17) for the connecting lines (13, 14) is joined with the interior space of the vacuum chamber (16).

13. The cooling apparatus according to claim 9, wherein the coolant comprises a butane, isobutene, propane, propene, ethyne, ethane, ethane, methane, argon, nitrogen, or a combination of any thereof.

14. A cooling apparatus equipped with a closed cooling circuit for cooling objects to semi-cryogenic or cryogenic temperatures of 230 K to 80 K, said closed cooling circuit for cooling objects to said semi-cryogenic or cryogenic temperatures according to the Joule Thomson cooling process, said cooling apparatus comprising (a) a cooling aggregate having: (i) a compressor for compressing a coolant supplied to the compressor in a gaseous state, wherein the coolant exits said compressor in a compressed gaseous state, (ii) an after-cooler connected downstream from the compressor from which after-cooler the coolant exits largely in gaseous form, (iii) a counterflow heat exchanger comprising a feed line and a return line, which are arranged in such a way that the compressed coolant is liquefied in the feed line as the relieved coolant flowing through the return line is being heated, and (iv) respective connecting lines for the feed line and for the return line, (b) a cooling head that is connected with the feed line to receive the liquefied coolant from the feed line and connected with the return line, wherein said cooling head is configured so that the coolant flows through the cooling head and the liquefied coolant evaporates, (c) a vacuum chamber for containing the cooling head, and (d) a throttle, wherein the cooling head is arranged within the vacuum chamber, which can be joined with a low-pressure source, and the cooling head is joined to the counterflow heat exchanger through the respective connecting lines with the feed line and return line, the counterflow heat exchanger is separate from and situated outside the vacuum chamber in which the cooling head is arranged, and the counterflow heat exchanger is not arranged in any other vacuum chamber, the connecting lines have vacuum insulation, the throttle is between the cooling head and the counterflow heat exchanger, and the vacuum chamber and the vacuum insulation for the connecting lines are directly joined together.

15. The cooling apparatus according to claim 14, wherein the compressor, after-cooler and counterflow heat exchanger are situated together in a floor-mounted device, the floor-mounted device further comprising a housing having a lead-through for the connecting lines (13, 14) that join the counterflow heat exchanger (7) with the vacuum chamber (16).

16. The cooling apparatus according to claim 14, wherein the vacuum chamber incorporates a tubular spacer, said spacer envelops the lead-through, and defines the distance between the cooling head and an inner wall of the vacuum chamber, said spacer having radial through holes.

17. The cooling apparatus according to claim 14, wherein the coolant comprises a butane, isobutene, propane, propene, ethyne, ethane, ethane, methane, argon, nitrogen, or a combination of any thereof.

Description

(1) The invention will now be explained in greater detail based on exemplary embodiments schematically depicted on the drawing. In the latter,

(2) FIG. 1 presents a closed coolant circuit with a cooling aggregate and a cooling head,

(3) FIG. 2 a sectional view of the cooling head with the connecting lines, and

(4) FIG. 3 a section according to line III-III on FIG. 2.

(5) The coolant circuit shown on FIG. 1 is most often referred to as a mixed gas Joule Thomson cooling process, and is described, for example, in Document EP 650574 A1. The coolant circuit comprises a compressor 1 for compressing the coolant supplied in gaseous form at 2. For example, the coolant can be a gas mixture consisting of propane, ethane, methane and nitrogen. The compressed coolant is fed via a line 3 to an oil separator 4, with which the oil potentially being mixed with the coolant in the compressor 1 is separated out. The coolant cleansed of oil is subsequently fed to an after-cooler 5, in which the heat supplied to the compressor 1 is removed from the coolant. The cooled, compressed, but still most often gaseous coolant is then fed via a line 6 to a counterflow heat exchanger 7, in which the coolant flowing through the coolant feed line 8 is cooled and liquefied by the coolant flowing in the coolant return line 9. In practice, the coolant feed line 8 and coolant return line 9 can be several meters long, and are often helically or spirally wound, so as to achieve a certain compactness of the thermal flow heat exchanger. The liquefied coolant is relieved by way of a throttle 10, so that the coolant can evaporate in the cooling head 11, allowing it to remove heat of evaporation from the environment. Since coolant passes through the cooling head 11, the latter is designed as a hollow cylinder, for example. As a consequence, the coolant flowing back from the cooling head 11 is heated to room temperature in the counterflow heat exchanger 7, wherein the returning coolant cools the inflowing coolant. In order to cool an object schematically marked 12, the latter is brought into contact with the cooling head 11. Therefore, the cooling head 11 consists of a thermally conductive material, such as copper.

(6) According to the invention, the cooling head 11 is joined with the counterflow heat exchanger 7 by connecting lines 13 and 14, so that the cooling aggregate 15 and the cooling head 11 arranged in a vacuum chamber 16 can be realized as separate structural units. The configuration according to the invention requires that the coolant cooled and liquefied in the heat exchanger 7 be transported over a more or less long distance by way of the connecting lines 13 and 14, so that a sufficient insulation must be ensured for the connecting lines.

(7) FIG. 2 provides a more detailed view of the cooling head with vacuum chamber, along with the connecting lines. As evident, the connecting lines 13 and 14 exhibit a vacuum insulation 17, the evacuated interior space of which is connected with the interior space of the vacuum chamber 16. The connecting lines 13 and 14 can here be designed as flexible tubes, so as to improve operability. The vacuum insulation 17 of the connecting line exhibits a flexible cladding tube 18, for example which can be designed as a stainless steel corrugated tube that preferably exhibits a steel jacket. The connecting lines 13 and 14 can also exhibit a corrugated outer contour, and have arranged between them spacers 19 that can also be flexible in design. The spacers 19 preferably exhibit a corrugated outer contour, so that the resultantly achieved linear contacts with the cladding tube 18 or connecting lines 13 and 14 minimize the heat transfer. As a consequence, the spacer 19 is used to mechanically, and hence thermally, decouple the connecting lines 13 and 14 to the cladding tube 18. It should be sufficiently flexible, temperature stabile, ageing resistant and outgassing free (e.g., Teflon, plastic, stainless steel). The connecting lines 13 and 14 are routed out of the vacuum insulation 17 at point 20. An eye must be kept out for slight thermal losses at the transition point 20. This can be achieved using materials with a slight thermal conductivity and a slight transition cross section (e.g., stainless steel). In addition, the transition point 20 can also be protected by conventional materials for heat insulation (e.g., foamed polystyrene, Armaflex).

(8) The connecting lines 13 and 14 can be thermally coupled. Alternatively, the connecting lines 13 and 14 can also be telescoped into each other. Depending on the cross section and length of the connecting line 13, the coolant can undergo a pressure reduction along the feed line, so that the coolant evaporates in the cooling head, just as in compression refrigeration machines, and heat is dissipated. In this case, the feed line simultaneously acts as the throttle.

(9) The vacuum insulation 17 is joined with a vacuum flange 21, through which the connecting lines 13 and 14 are passed, and routed to the cooling head 11. In order to improve the mechanical stability of the cooling head 11, the cooling head 11 and vacuum flange 21 have arranged between them a spacer 22, for example which can consist of Teflon, ceramic or stainless steel, and should be outgassing-resistant, low temperature-suitable, embrittlement-resistant and ageing-resistant. Care must here be taken to ensure that the spacer 22 is thermally decoupled from the vacuum flange 21 to a sufficient extent, and that there is a good atmospheric permeability relative to the cladding tube 18. As evident from the cross sectional view on FIG. 3, the spacer 22 exhibits several radial through holes 24, so that the evacuated interior space of the vacuum insulation for the connecting lines is conductively connected with the evacuated interior space of the vacuum chamber 16. A flange or port for connection to a vacuum pump is marked 23.

(10) The cooling head becomes extremely low-vibration if coolant flows uniformly through the cooling head and the cooling head is mechanically stabilized by means of spacers.

(11) Typical areas of application for the invention include the cooling of heavy duty laser amplifiers as well as various cooling operations in analytical chemistry, in the field of superconductivity, astronomy, and also generally in research and development, along with medical diagnostics.