US3362174A - Gaseous condensation in vacuum with plural refrigerants - Google Patents

Gaseous condensation in vacuum with plural refrigerants Download PDF

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Publication number
US3362174A
US3362174A US401371A US40137164A US3362174A US 3362174 A US3362174 A US 3362174A US 401371 A US401371 A US 401371A US 40137164 A US40137164 A US 40137164A US 3362174 A US3362174 A US 3362174A
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nitrogen
chamber
refrigerating
heat exchange
hydrogen
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US401371A
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Carbonell Emile
Martin Monique
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Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Air Liquide SA
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
    • F25J1/0275—Construction and layout of liquefaction equipments, e.g. valves, machines adapted for special use of the liquefaction unit, e.g. portable or transportable devices
    • F25J1/0276—Laboratory or other miniature devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D8/00—Cold traps; Cold baffles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
    • F25J1/0012—Primary atmospheric gases, e.g. air
    • F25J1/0015—Nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/0035—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by gas expansion with extraction of work
    • F25J1/0037—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by gas expansion with extraction of work of a return stream
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/004—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by flash gas recovery
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/0045—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by vaporising a liquid return stream
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0047—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle
    • F25J1/005—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle by expansion of a gaseous refrigerant stream with extraction of work
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0047—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle
    • F25J1/0052—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
    • F25J1/0062—Light or noble gases, mixtures thereof
    • F25J1/0067—Hydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0203—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle
    • F25J1/0208—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle in combination with an internal quasi-closed refrigeration loop, e.g. with deep flash recycle loop
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
    • G01M9/02—Wind tunnels
    • G01M9/04—Details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/20—Processes or apparatus using other separation and/or other processing means using solidification of components
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/14—External refrigeration with work-producing gas expansion loop
    • F25J2270/16—External refrigeration with work-producing gas expansion loop with mutliple gas expansion loops of the same refrigerant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2280/00—Control of the process or apparatus
    • F25J2280/30—Control of a discontinuous or intermittent ("batch") process

Definitions

  • the present invention relates to a process by which a chamber connected to a source of gas is maintained under vacuum by gas entering the chamber being deposited in the solid state on a device for supplying cold by indirect heat exchange with at least one liquefied refrigerating fluid, in which the solid deposits of this gas on the means supplying cold are periodically liquefied, at least in part, by warming up of this latter and are discharged from the chamber.
  • Processes of this type are more especially employed for ensuring rapid discharges of gas with considerable rates of flow for the purpose of aerodynamic studies.
  • the conduit in which it is desired to ensure the rapid discharge flow is connected at one end to a source of the said gas and at the other end to a chamber under vacuum, in which this gas is deposited in the solid state in pro portion as it reaches the said chamber.
  • This chamber is generally known under the name of cryopump; the vacuum which obtains therein should generally be not more than 0.1 to 0.01 millibar.
  • the gas of which it is desired to ensure the flow is generally deposited on metal plates having good thermal contact with the ducts in which circulates a liquefied refrigerating fluid formed by a gas which is more volatile than the gas which is to be deposited in the solid state.
  • One or more other refrigerating fluids can be used for assuring a preliminary cooling of the gas which enters into the vacuum chamber.
  • this gas can be solidified by heat exchange with liquid hydrogen, after a first cooling by heat exchange with liquid nitrogen.
  • it can be solidified by heat exchange with liquid helium, after a first cooling by heat exchange with liquid hydrogen and optionally liquid nitrogen.
  • the heat exchange between the gas to he solidified and the more volatile refrigerating fluid becomes less satisfactory as soon as the solid layer on the heat exchange plates has reached a certain thickness, so that the gas intake capacity of the cryopump decreases. It is then expedient to regenerate the heat exchange arrangement by a warming up which is sufficient to melt the solid deposits on the plates. A relatively hot fluid is then caused to pass through the heat exchange ducts, this ensuring the melting of the solid layer deposited on the heat exchange plates. The liquid formed is then discharged from the chamber, the latter is once again placed under vacuum by means of an auxiliary vacuum pump and then it is put again into operation by re-establishing the circulation of the refrigerating fluids.
  • the periodic regeneration of the heat exchange plates of the chamber involves a considerable loss of cold and as a consequence an appreciable energy consumption for re-est'ab'lishing the cold state of the chamber after each regeneration, since the chamber must be cooled from a temperature which is higher than the melting point of the gas to be deposited in the solid state down to a temperature such that its 3,362,174 Patented Jan. 9, 1968 vapour pressure by sublimation does not exceed the desired value, i.e., the chamber must be cooled several tens of degrees, at a temperature level (liquefaction point of hydrogen or helium, for example) at which any production of cold requires a high energy consumption.
  • the present invention has for its object to overcome this disadvantage and to reduce to a large degree the energy consumption which is necessary to ensure the operation of a cryopump. It permits of recovering a considerable fraction of the cold which was hitherto lost because of the evacuation of the liquid formed by the melting of the solid deposits on the heat exchange plates during their regeneration. In addition, it is possible therewith to facilitate the liquefaction of the more volatile refrigerating fluid provided for ensuring the solidification of the gas to be drawn into the cryopump.
  • the invention is characterised in that the liquid formed during the warming up of the solid deposits, after the said liquid has been withdrawn from the chamber, is vapourised and optionally warmed up so as to recover some of the supply of cold and to utilize the recovered cold to effect the deposition in the solid state of the gas entering the chamber.
  • the invention moreover preferably comprises the following embodiments, separately or in any combination:
  • the second refrigerating fluid is the same gas as that to be deposited in the solid state in the chamber, and the liquid formed during the warming up of the solid deposits is combined with this second liquefied refrigerating fluid.
  • the chamber to be kept under vacuum is connected alternately to one or other of the cryopumps 1 and 2, one of these latter 1 being in operation while the other 2 is undergoing regeneration during the period of operation which is illustrated.
  • cryopumps connected to the chamber in which it is desired to assure the flow of nitrogen through a conduit 1A or 2A, is equipped with metal plates formed with ducts in which the refrigerating fluids circulate.
  • a first system of plates shown diagrammatically at 5, 6 is connected to the refrigeration cycle for the production of liquid nitrogen;
  • a second system of plates 3, 4 is connected to the refrigerating cycle for the production of liquid hydrogen.
  • Each of the cryopumps is provided in its lower part with a receiver 7, 8, in which is to be collected the liquefied nitrogen formed with the defrosting of the plates 3, 4 of the liquid hydrogen cycle, the said tanks being connected by a discharge valve 9, and conduits 17, 18, 19 to the liquid nitrogen storage reservoir 20.
  • a coil 70, 8a disposed in the receiver ensures the melting of the blocks of solid nitrogen which would become detached from the plates before complete melting and would pose the danger of obstructing the valves or discharge conduits.
  • the tanks 7, 8 are in addition connected by valves 11, 12 and conduits 13, 14 to a vacuum pump 15, designed to ensure the preliminary vacuum in the cryopump at the moment of starting up and to eliminate continuously those gases (neon, hydrogen, helium) which cannot be condensed and which are contained in the nitrogen to be pumped. Finally, the heat insulation of the cryopumps is assured by means of double Walls equipped with liquid nitrogen coils 107 and 108.
  • the nitrogen cycle provided for ensuring the preliminary cooling of the nitrogen to be deposited in the cryopump down to a temperature of about 90 K. is of a known type.
  • the nitrogen recycled through the pipe 74 is brought by the compressor 21 to a pressure of approximately 80 bars absolute. Discharged from the compressor through the pipe 22, it is divided into two parts. The first part is cooled in the exchanger 24 to approximately 93 K. in counter-current with the nitrogen discharged under vacuum (absolute pressure of about 120 millibars) by the pump 102 after vapourisation in heat exchange with the hydrogen cycle in the region of 63 K., which is the temperature of the triple point of nitrogen.
  • the second part of the nitrogen is cooled in the first place in the exchanger 23 to 196 K. in counter-current with the recycled nitrogen; one fraction is then conducted through the pipe 25 to the expansion machine 26, where it is expanded to approximately 1.3 bars and is cooled to about 80 K., then combined with the gaseous nitrogen originating from the operating cryopump and with the nitrogen vapours originating from the liquid nitrogen reservoir; the combined flow is then recycled through the pipe 72 in counter-current into the exchanger 28 in order to ensure the cooling of the residual part of the nitrogen under pressure to about 155 K.
  • the hydrogen cycle permitting the final temperature of 33 K. to be reached in the operating cryopump is also of a known type, with production of cold by two expansions with external work at difierent temperature levels.
  • the hydrogen recycled through the pipe 98 is brought by the compressor 40 to a pressure of about 25 bars absolute. It is introduced by way of the pipe 41 into the exchanger 42, in counter-current with the low-pressure hydrogen recycled from the cryopump undergoing defrosting, and then through the pipe 43 into the exchanger 44, where it is cooled to about 75 in heat exchange with the low-pressure hydrogen recycled from the operating cryopump and the expansion machines.
  • the hydrogen under pressure then passes by Way of the pipe 45 into the exchanger 46, where it is cooled to approximately 66 K. by vapourisation of liquid nitrogen at 120 millibars absolute.
  • a first fraction thereof is then sent through the pipe 47 to the expansion turbine 48 in which it is expanded to about atmospheric pressure, then combined by means of the pipe 49 with the recycled low-pressure hydrogen and introduced with the latter through the pipe 88 into the exchanger 56.
  • the remaining hydrogen under pressure is introduced through the pipe 50 into the exchanger 51 and cooled to 51 K. by the recycled low-pressure hydrogen.
  • a fresh fraction thereof is then diverted and sent through the pipe 52 to the expansion turbine 53 in which it is expanded to about atmospheric pressure; cooled to 21 K., at about the dew point of the hydrogen, it is combined by means of the pipe 54 with the hydrogen vapourised in the operating cryopump and returned with said hydrogen to the cold end of the exchanger 58.
  • the hydrogen under pressure is then sent successively through the pipes 55 and 57 into the exchangers 56 and 58, where it is cooled to about 25 K. by heat exchange with the low-pressure hydrogen originating from the operating cryopump and the expansion engines. It is then returned through the pipe 59 into the operating cryopump.
  • the preliminary cooling to K. of the nitrogen which is drawn in is ensured by the vapourisation under atmospheric pressure in the ducts of the heat exchange plates 5 of liquid nitrogen introduced through the pipe 60, the open valve 61 (the valve 62 connected to the plates 6 of the cryopump 2 undergoing regeneration being closed) and the pipe 63.
  • the vapourised nitrogen is discharged through the pipe 65, the open valve 67 (the corresponding valve 68 connected to the cryopump 2 being closed) and the pipe 69 towards the pipe 71 for the recycling of the cold nitrogen at low pressure.
  • coils 107 and 108 providing part of the heat insulation of the cryopumps, are fed with liquid nitrogen drawn off through pipe 103 from pipe 60, then sent respectively through pipes 105 and 106 to coils 107 and 108.
  • the vapourised nitrogen at the outlet of coils 107 and 108 is withdrawn through pipe 109 and added to the low pressure nitrogen recycle stream of pipe 73 at the cold end of heat exchanger 23.
  • the final cooling to 33 K. in the cryopump 1, causing the freezing of the drawn-in nitrogen, is assured by the vapourisation at 20 K. under atmospheric pressure in the ducts of the heat exchange plates 3 of liquid hydrogen introduced through the pipe 59, the open expansion valve 75 (the corresponding valve 76 connected to the plates 4 of the cryopump 2 being closed) and the pipe 77.
  • the vapourised hydrogen is discharged through the pipe 79, the open valve 83 (the corresponding valve 84 being closed) and the pipe 85 towards the cold end of the exchanger 58 of the hydrogen liquefaction cycle.
  • the melting of the solidified nitrogen deposited on the plates 4 cooled with liquid hydrogen is assured as follows.
  • the low-pressure hydrogen warmed up in the exchanger 44 to approximately K. is sent through the pipe 91 and the open valve 94 (the valve 93 connected to the corresponding cycle of the cryopump 1 being closed) and then through the pipe 96 into the coil 8a in the sump 8 of the cryopump, where it provides for the melting of the blocks of solid nitrogen which could become detached from the plates 4 before complete melting; it then passes into the ducts of the plates 4, thereby ensuring the progressive warming up of the latter to 80 K.
  • the major part of the solid nitrogen deposited on the plates 4 is liquefied and flows into the tank 8. It is sent from thence through the open valve 10 and the pipes or conduits 18 and 19 to the liquid nitrogen storage reservoir, with a view to being used for supplying cold, either in the precooling plate 5 or 6 of the cryopumps, or in the hydrogen and nitrogen refrigerating cycles in the exchangers 46 and 24 already referred to.
  • a certain quantity of solid nitrogen is sublimed and produces a raising of the pressure in the cryopump.
  • a process for condensing normally gaseous medium under subatmospheric conditions in alternating chambers comprising (1) condensing said gaseous medium in one of said alternating chambers by indirect heat exchange with a plurality of refrigerating liquids of distinctly different boiling points in closed separate refrigerating circuits while maintaining said one chamber under subatmospheric conditions, said closed refrigerating circuits being included in each of said alternating chambers, (2) withdrawing thus condensed gas from said other chamber, (3) vaporizing a portion of said withdrawn condensed gas to produce at least a portion of the refrigeration for one of the circuits in one of said chambers, (4) passing another portion of said withdrawn condensed gas in heat exchange with at least one of said refrigerating circuits, and (5) alternating the flow of the gaseous medium so that it is condensed as in step (1) in the other chamber and is withdrawn from the one chamber as in step (2) above.
  • a process as claimed in claim 3 and melting the solid in the chambers to form a liquid, and removing the latter liquid from the chambers in liquid phase.
  • one of said refrigerating liquids being nitrogen and the other being a liquid boiling lower than nitrogen.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
US401371A 1963-10-14 1964-10-05 Gaseous condensation in vacuum with plural refrigerants Expired - Lifetime US3362174A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR950527A FR1388726A (fr) 1963-10-14 1963-10-14 Procédé de maintien sous vide d'une enceinte

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US3362174A true US3362174A (en) 1968-01-09

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US401371A Expired - Lifetime US3362174A (en) 1963-10-14 1964-10-05 Gaseous condensation in vacuum with plural refrigerants

Country Status (6)

Country Link
US (1) US3362174A (de)
BE (1) BE654085A (de)
DE (1) DE1279887B (de)
FR (1) FR1388726A (de)
GB (1) GB1073928A (de)
NL (1) NL6411947A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3416324A (en) * 1967-06-12 1968-12-17 Judson S. Swearingen Liquefaction of a gaseous mixture employing work expanded gaseous mixture as refrigerant
US3511058A (en) * 1966-05-27 1970-05-12 Linde Ag Liquefaction of natural gas for peak demands using split-stream refrigeration
US4274851A (en) * 1976-08-16 1981-06-23 The University Of Sydney Gas recovery of sulphur hexafluoride

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5799509A (en) * 1997-08-22 1998-09-01 The Boc Group, Inc. Multi-component recovery apparatus and method
CN110563063A (zh) * 2019-09-29 2019-12-13 江苏苏境电力科技有限责任公司 用于脱硫废水零排放系统的蒸汽湿式自冷凝装置及方法
CN112556967B (zh) * 2020-12-30 2022-08-23 太原理工大学 一种复杂结构管网气固两相运移模拟试验装置

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Also Published As

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DE1279887B (de) 1968-10-10
GB1073928A (en) 1967-06-28
FR1388726A (fr) 1965-02-12
BE654085A (de) 1965-04-07
NL6411947A (de) 1965-04-15

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