US3910063A - Cooling system - Google Patents

Cooling system Download PDF

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Publication number
US3910063A
US3910063A US455398A US45539874A US3910063A US 3910063 A US3910063 A US 3910063A US 455398 A US455398 A US 455398A US 45539874 A US45539874 A US 45539874A US 3910063 A US3910063 A US 3910063A
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United States
Prior art keywords
fluid
cooling
supply duct
main
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US455398A
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English (en)
Inventor
Gijsbert Prast
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US Philips Corp
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US Philips Corp
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Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3910063A publication Critical patent/US3910063A/en
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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
    • 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
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant

Definitions

  • the invention relates to a cooling system for cooling at least one object, which system is provided with a compression device for compressing a cooling fluid to a higher pressure, the compressor outlet being connected to a main supply pipe via at least one heat exchanger in which the compressed fluid is cooled to a temperature below the inversion temperature associated with the higher pressure.
  • the system has a plurality of heat exchange elements for heat exchange with the objects to be cooled, each element having a fluid inlet and a fluid outlet, which inlets are connected each via an auxiliary supply pipe to the main supply pipe and have fluid supplied to them via a pressure reducing device in which compressed fluid which has been cooled in the heat exchanger is reduced in pressure.
  • the heat exchange elements take the form of cooling coils arranged in storage containers for liquefied .gas.
  • the cooling coils ensure that the pressure in the storage containers does not exceed a given value.
  • the fluid which has been precooled to a temperature below the' associated inversion temperature, is throttled from a higher pressure to a much lower pressure.
  • the temperature of the fluid drops, owing to isenthalpic expansion (Joule-Kelvin effect) and/or the fluid exhibits a phase transition from the gaseous to the liquid state, at least part of the fluid being liquefied.
  • This liquefaction obviously requires that the temperature and the pressure should assume values below the critical temperature and the critical pressure respectively.
  • each auxiliary supply pipe includes an expansion valve as a pressure reducing device.
  • each of the auxiliary supply pipes passes a fraction of the main flow through the main supply pipe.
  • the expansion valves in the auxiliary supply .pipes have passages of comparatively small internal cross-sectional areas. Owing to these small-area passages impurities readily deposit in the expansion valves, with the result that the fluid flows through the auxiliary supply pipes will become widely different and that some valves may even become clogged.
  • the cooling of several Dewar flasks filled with liquid gas is impaired or even stopped so that the pressure in these flasks will rapidly rise.
  • the fixed or fixedly set restrictions included in the auxiliary supply pipes ensure a distribution of the fluid flow between the auxiliary supply pipes which is as equal as possible. Thus substantially equal cooling powers are available for the objects to be cooled.
  • the restrictions may have comparatively large-area passages associated with pressure drops which, taken absolutely, are small, for example 0.1 atmosphere, but in relation to the pressure drops in the remainder of each auxiliary pipe are large, for the distribution of the fluid flow between the auxiliary pipes is determined by the overall pressure drop in the supply pipes. Because the pressure drop in the pan of the auxiliary pipe downstream of the heat exchange element is greatly dependent upon the thermal load imposed on this element, (for example a greater gas fraction in the discharged auxiliary fluid in the case of increased evaporation), the distribution of the fluid flow between the heat exchange elements also would be dependent of the thermal load, which is unacceptable. Hence the restrictions in the auxiliary supply pipes are located at the fluid inlet sides of the heat exchange elements. Owing to the comparatively large-area passages of the restrictions clogging is very unlikely.
  • the refrigeration capacity of the cooling system need only be such as to compensate for the leakage of heat into the liquefied gas storage containers.
  • the latter is frequently optimized so that in normal operation hardly any unnecessary cooling power is available.
  • the accuracy with which the cooling power and hence the fluid flow is distributed between the heat exchange elements has to satisfy stringent requirements, in particular when part of the fluid supplied to these elements is gaseous and the remainder is liquid, for refrigeration mainly utilizes the latent heat (the heat of evaporation) of liquid fluid and substantially no sensible heat, so that in the refrigerating process proper, the gaseous fluid is notsignificant.
  • the cooling system according to the invention is characterized in that the outlets of the heat exchange elements open into a container for separating gaseous fluid from liquid fluid, the gas space of the container being connected to the suction inlet of the compression device while the liquid space is in thermal contact with a part of the main supply pipe, which part lies downstream of the pressure reducing device, for
  • the cooling system shown has a compression device comprising a lowpressure compressor 1 and a high-pressure compressor 2 having an outlet 3.
  • the outlet 3 is connected to a cooler 4 in which the heat of compression of the compressed fluid, in the present case helium under a pressure of for example 30 atm., is dissipated.
  • the compressed helium flows through a heat exchanger 5 in which it exchanges heat with helium at a lower pressure and temperature.
  • a heat exchanger 6 the high-pressure helium is cooled by a refrigerator 7 to a temperature of for example 60K.
  • the highpressure helium agains exchanges heat with helium at a lower pressure and temperature in the heat exchanger 8 and subsequently is cooled to a temperature of for example 15K by a refrigerator 10 in a heat exchanger 9. The temperature is then further decreased in a heat exchanger 11 by heat exchange with helium at a lower pressure and temperature.
  • the high-pressure helium finally has a temperature below its critical temperature of -5.3K.
  • the high-pressure helium then enters a throttle valve 12 which-acts as a pressure reducing device and in which the helium expands to below its critical pressure of 2.26 atm. and part of it, about 50%, liquefies.
  • the throttle valve 12 is included in a main supply pipe 13 to which, in the present embodiment, three parallel auxiliary supply pipes 14 are connected which lead to inlets 15 of heat exchange elements 16 in the form of cooling coils which are arranged in the vapor space of closed storage containers 17 which contain liquid helium.
  • the outlets 18 of the heat exchange elements 16 are connected to a common return flow pipe 19 which opens in a container 20 the vapor space 200 of which communicates via the heat exchangers 1 l, 8 and 5 with the suction inlet 21 of the compressor 1.
  • the auxiliary supply pipes 14 include substantially equal restrictions 22.
  • the mixture of gaseous and liquid helium issuing from the throttle valve 12 is completely converted into the liquid phase by heat exchange with the liquid helium contained in the liquid space 20b of the container 20.
  • part of the main supply pipe 13 is formed as a heat exchanger arranged in the container 20.
  • the flow of liquid helium is equally divided between the three heat exchange elements by means of the restrictions 22, which may be simple diaphragms.
  • the heat exchange elements part of the liquid helium in the embodiment under consideration, 50%, evaporates owing to condensation on these elements of helium evaporated in the containers 17 as a result of inward leakage of heat.
  • the pressure in the containers remains low.
  • the mixture of gas and liquid which issues from the heat exchange elements is separated into gas and liquid in the container 20.
  • the 50% in the form of liquid helium just ensures condensation of the 50% in the form of gaseous helium in the helium flow from the throttle valve 12.
  • Precooling of the high-pressure helium may be effected in cold gas refrigerators.
  • expansion engines pietron expansion engines, expansion turbines
  • a part tapped from the high pressure helium flow expands while performing mechanical work, in order to produce cold which is used to precool the high-pressure helium main flow.
  • a closed system operable with a cooling fluid flowing through a continuous passage for cooling a plurality of objects, and including first means for compressing said fluid to a first high pressure, second means for cooling said fluid to a reduced temperature below the inversion temperature associated with said high pressure, a tubular cooling element with inlet and outlet means, a main supply duct for conveying said reduced temperature fluid, an auxiliary supply duct communicating each of said inlet means with said main supply duct, a main return duct communicating each of said outlet means with said first means, the improvement in combination therewith comprising Joule- Kelvin throttle valve means in said main supply duct for reducing the pressure of said fluid at said reduced temperature before it flows to said cooling elements, and fluid flow restriction means in each of said inlet means, said; restriction means all having substantially equal internal cross-sectional areas.
  • Apparatus according to claim 1 further comprising downstream of said valve means a container having liquid and vapor spaces therein respectively for containing liquefied gas and vapor thereof, said main-supply duct being in heat exchange relationship with said liquefied gas in said liquid spacefor condensing gaseous fluid in said main supply duct, and said main return duct feeding into said vapor space which then feeds into said first means.
  • Apparatus according to claim 2 wherein said objects each comprise a Dewar flask for containing a quantity of liquefied gas therein, and situated within each flask is one of said cooling elements and restriction means.
  • said second means comprises a plurality of heat exchangers for' successively cooling said cooling fluid, each heat exchanger including a source of cold.

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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)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
US455398A 1973-04-09 1974-03-27 Cooling system Expired - Lifetime US3910063A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7304885A NL7304885A (de) 1973-04-09 1973-04-09

Publications (1)

Publication Number Publication Date
US3910063A true US3910063A (en) 1975-10-07

Family

ID=19818593

Family Applications (1)

Application Number Title Priority Date Filing Date
US455398A Expired - Lifetime US3910063A (en) 1973-04-09 1974-03-27 Cooling system

Country Status (9)

Country Link
US (1) US3910063A (de)
JP (1) JPS5322979B2 (de)
CA (1) CA997162A (de)
CH (1) CH573091A5 (de)
DE (1) DE2416070A1 (de)
FR (1) FR2224715B1 (de)
GB (1) GB1468539A (de)
NL (1) NL7304885A (de)
SE (1) SE397579B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030899A (en) * 1975-02-24 1977-06-21 U.S. Philips Corporation Cooling device
US4030900A (en) * 1975-02-24 1977-06-21 U.S. Philips Corporation Cooling device
US7234331B2 (en) 2002-09-26 2007-06-26 Newfrey Llc Rekeyable lock assembly
US20090183860A1 (en) * 2008-01-21 2009-07-23 Bruker Biospin Sa, Societe Anonyme Heat exchanger device and nmr installation that comprises such a device
JP2013174377A (ja) * 2012-02-24 2013-09-05 Taiyo Nippon Sanso Corp ヘリウム液化装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3350896A (en) * 1966-01-11 1967-11-07 Westinghouse Electric Corp Multiple evaporator refrigeration systems
US3442093A (en) * 1966-07-01 1969-05-06 Philips Corp Apparatus and ejector for producing cold
US3447339A (en) * 1966-05-25 1969-06-03 Philips Corp Cold producing systems
US3464230A (en) * 1966-07-01 1969-09-02 Philips Corp Systems for producing cold and ejectors in such systems
US3496735A (en) * 1967-07-27 1970-02-24 Philips Corp Ejector in refrigerating device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3350896A (en) * 1966-01-11 1967-11-07 Westinghouse Electric Corp Multiple evaporator refrigeration systems
US3447339A (en) * 1966-05-25 1969-06-03 Philips Corp Cold producing systems
US3442093A (en) * 1966-07-01 1969-05-06 Philips Corp Apparatus and ejector for producing cold
US3464230A (en) * 1966-07-01 1969-09-02 Philips Corp Systems for producing cold and ejectors in such systems
US3496735A (en) * 1967-07-27 1970-02-24 Philips Corp Ejector in refrigerating device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030899A (en) * 1975-02-24 1977-06-21 U.S. Philips Corporation Cooling device
US4030900A (en) * 1975-02-24 1977-06-21 U.S. Philips Corporation Cooling device
US7234331B2 (en) 2002-09-26 2007-06-26 Newfrey Llc Rekeyable lock assembly
US20090183860A1 (en) * 2008-01-21 2009-07-23 Bruker Biospin Sa, Societe Anonyme Heat exchanger device and nmr installation that comprises such a device
US8683816B2 (en) * 2008-01-21 2014-04-01 Bruker Biospin Sa Heat exchanger device and NMR installation that comprises such a device
JP2013174377A (ja) * 2012-02-24 2013-09-05 Taiyo Nippon Sanso Corp ヘリウム液化装置

Also Published As

Publication number Publication date
FR2224715A1 (de) 1974-10-31
CA997162A (en) 1976-09-21
SE397579B (sv) 1977-11-07
DE2416070A1 (de) 1974-10-24
JPS5322979B2 (de) 1978-07-12
NL7304885A (de) 1974-10-11
CH573091A5 (de) 1976-02-27
JPS49129942A (de) 1974-12-12
FR2224715B1 (de) 1977-10-14
GB1468539A (en) 1977-03-30

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