US3908397A - Cooling system - Google Patents

Cooling system Download PDF

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Publication number
US3908397A
US3908397A US455399A US45539974A US3908397A US 3908397 A US3908397 A US 3908397A US 455399 A US455399 A US 455399A US 45539974 A US45539974 A US 45539974A US 3908397 A US3908397 A US 3908397A
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United States
Prior art keywords
fluid
cooling
duct
heat
space
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Expired - Lifetime
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US455399A
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English (en)
Inventor
Gijsbert Prast
Jan Mulder
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US Philips Corp
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US Philips Corp
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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
    • 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 to a lower temperature at least one space which is closed in operation.
  • the system comprises at least one cooling element which' is placed in said space and through which a cooling fluid can flow, and the inlet of which is connected to a fluid supply pipe passed through a wall of the space, while the outlet is connected to a fluid discharge pipe passed through a wall of the space.
  • Cooling systems of the type referred to are described in British Pat. No. 521,792 and in US. Pat. No. 2,753,691, FIG. 4.
  • the cooling elements are in the form of cooling coils placed in storage containers for liquefied gas.
  • the cooling coils by recondensing liquid vaporized by heat leakage into the container or by direct cooling of the liquid, prevent the pressure in the storage containers from exceeding a given value.
  • the known cooling systems have a disadvantage which manifests itself in the case of increased heat flow from the ambient atmosphere into the cooled container as a result of leakage, for example when the evacuated sheath of the container has leaks due to mechanical shock or vibration.
  • the increased heat leakage results in a substantial rise of the temperature in the container so that the cooling fluid flowing through the cooling coil is heated. This means that a considerable part of the available cooling power is wasted.
  • the heat leaking into the container spreads to the remainder of the cooling system.
  • the system comprises further containers equipped with cooling elements, cooling of these containers also is jeopardized.
  • the rise in temperature in the leaking container is accompanied by a rise in pressure.
  • leakage even involves additional losses of cooling power. This state of affairs is not improved by a vent valve opening at a given maximum pressure.
  • a cooling system according to the invention is characterized in that a blocking device is provided which completely or partly blocks the flow of fluid to the cooling element in response to an intolerable rise in temperature of the cooled space.
  • the blocking device may be a temperature sensor which is placed in the space to be cooled and operates a valve in the fluid supply pipe.
  • moving parts are involved, which increases the complexity of the system.
  • an advantageous embodiment of the cooling system according to the invention is characterized in that the blocking device comprises a restriction included in the part of the fluid supply pipe situated within the cooled space and by a heat exchanger included on the one hand in the fluid supply pipe on the side of the restriction remote from the cooling element and on the other hand in the fluid discharge pipe.
  • the temperature of the cooling fluid issuing from the cooling element is substantially equal to the temperature at which it enters the element.
  • the heat exchanger in the fluid supply and discharge pipes is passive.
  • the cooling fluid flowing towards the cooling element is heated in the heat exchanger by warm cooling fluid flowing from the cooling element, possibly after vaporization.
  • the restriction primarily because of the reduced density (transition from liquid to gas) or because of the reduced density and the increased viscosity (gas) of the cooling fluid, abruptly offers a flow resistance such to the cooling fluid that substantially no fluid is allowed to pass.
  • a cooling system having a blocking device which operates automatically and reliably and comprises no moving parts, and in the case of heat leakage into the cooled container substantially blocks the flow of cooling fluid to this container, with the re sult that substantially no cooling power is wasted and the remainder of the system is unaffected by the heat leakage into the said container.
  • the cooling system in which in operation gaseous cooling fluid is supplied to the fluid supply pipe, is characterized in that the restriction is a laminar restriction.
  • the laminar restriction may for example comprise a system of small-diameter passages.
  • the restriction according to the invention is a turbulent restriction.
  • a turbulent restriction such as a diaphragm provides the advantage that in general its manufacture is simpler than that of a laminar restriction.
  • a Dewar flask 1 contains liquid hydrogen.
  • a cooling coil 3 is placed, the inlet of which is connected to a supply pipe 4 for cooling fluid andthe outlet of which is connected to a discharge pipe 5.
  • a heat exchanger 6 for heat exchange with the cold head 7 ofa cold gas refrigerator 8 is connected at one end to the supply pipe 4 and at the other end to the discharge pipe 5.
  • Said supply and discharge ducts 4 and have a first part 4a, 5a, respectively extending from the refrigerator 8 to said flask or closed space 1, and a second part 4a, 5a, respectively within said space, with adjacent portions of said second parts forming said heat exchanger.
  • a pumping device 9 connected in the supply pipe 4 serves to circulate the cooling fluid, in this case pressurized gaseous helium.
  • the part of the supply pipe 4 situated within the vapor space 2 of the Dewar flask 1 includes a laminar restriction 10, while outside the Dewar flask a heat exchanger l 1 is included in the supply pipe 4 and also in the discharge pipe 5.
  • the restriction or first means 10 and the heat exchanger or second means 11 together form a blocking device.
  • the gaseous helium at a pressure of for example 20 atmospheres which circulates in the pipe system is cooled in the heat exchanger 6 to for example 15 K.
  • the cold gaseous helium just ensures recondensation of hydrogen vaporized by heat leakage.
  • the hydrogen pressure remains at a value below atmospheric pressure.
  • the temperature of the helium gas streams entering and leaving the cooling coil are nearly equal.
  • the temperatures of the two helium gas streams which pass through the heat exchanger 11 are substantially equal also.
  • this heat exchanger 11 plays no active part.
  • the hot helium gas issuing from the Dewar flask heats the cold helium stream from the cold head 7.
  • the laminar restriction 10 allows only a fraction of the initial helium stream to pass. I-Ience substantially no thermal energy is wasted in the Dewar flask l, and at the same time heating of the cold head 7 of the cold gas refrigerator 8 is prevented.
  • the three turbulent restrictions have substantially equal internal cross-sectional areas so that in normal operation they also ensure that substantially equal cooling fluid streams flow to the cooling coils.
  • the common discharge pipe 36 opens into a container 45 the vapor space 46 of which communicates via heat exchangers 47, 48 and 49 with the suction inlet 50 of a low-pressure compressor 51 the outlet of which is coupled to the inlet of a high-pressure compressor 52.
  • the outlet 53 of the high-pressure compressor 52 is connected to the common supply pipe 35 via, in the enumerated order, a cooler 54, heat exchangers 49, 55, 48, 56 and 47, a throttle valve 57 and a heat exchanger 58 arranged in the container 45.
  • a cold source 60 forms part of the heat exchanger 55, and a cold source 61 forms part of the heat exchanger 56.
  • the two cold sources may be the cold areas of a two-stage cold gas refrigerator.
  • the cooling device uses helium as the cooling fluid. In operation gaseous helium is compressed to a high pressure in the compressors 51 and 52 and then supplied via the outlet 53 to the cooler 54 in which the compressed helium gives off the heat of compression. In the heat exchanger 49 the compressed helium then gives off heat to helium at a lower pressure and temperature. In the heat exchanger the high-pressure helium is cooled by the cold source to a temperature of, for example, 60K
  • the heat exchanger 48 again gives off heat to helium at a low pressure and temperature.
  • the compressed helium is cooled further to a temperature of, for example, l5K by the cold source 61.
  • the high-pressure helium again gives off hcat to helium at a lower pressure and temperature.
  • the high-pressure helium then enters a throttle valve 57 in which it expands isenthalpically to below the critical pressure of 2.26 atmospheres and to below the critical temperature of 5.3K, so that about 50 percent of the gaseous helium is liquefied.
  • the remaining 50 percent of gaseous helium is condensed by the liquid helium in the container 45, so that substantially only liquid helium is supplied to the cooling coils 26, 27 and 28. In these cooling coils about one-half of the helium flowing through them is vaporized.
  • helium in the gaseous state is separated from helium in the liquid state.
  • the 50 percent of liquid helium then are used to condense the 50 percent of gaseous helium in the helium stream from the throttle valve 57.
  • the helium vapor in the container 45 is sucked into the compressor 51.
  • a cooling system operable with a source of cooled fluid for refrigerating a closed space, including a cooling element which is situated in said space and through which said fluid is flowable for refrigerating said space, a supply duct for communicating said fluid from said source to said cooling element, a discharge duct for communicating said fluid from said element to said source, and means for circulating said fluid through said system, the improvement in combination therewith, wherein said supply and discharge ducts each comprise a first part extending from said source to said closed space and a second part within said closed space extending to said cooling element, said first part of said supply and discharge ducts having adjacent portions in heat exchange relationship forming a heat exchanger, the improvement being a blocking device comprising said heat exchanger and a fluid flow restriction means in said second part of the supply duct, whereby a heat leak into said closed space causing a temperature rise therein causes heat transfer into fluid in said cooling element and in said discharge duct, and further heat transfer from fluid in said discharge duct to fluid in said supply duct via said heat
  • said restriction means comprises a laminar flow restriction means.
  • said source of cooling fluid comprises continuous duct means including as parts thereof said supply and discharge ducts, a quantity of helium in said duct means, and a cold gas refrigerator for cooling said helium in said duct means.
  • a cooling system operable with a source of fluid for refrigerating a closed space, including a cooling element which is situated in said space whereby said fluid becomes heated and through which said fluid is flowable for refrigerating said space, a supply duct for communicating said fluid from said source to said cooling element, a discharge duct forcommunicating said fluid from said element to said source, and means for circulating said fluid through said system, the improvement in combination therewith, comprising first means in said closed space, and second means for transferring heat from said fluid heated in said cooling element to fluid in said supply duct upstream of said space, said first means operable to restrict flow in the supply duct of said fluid when it has been heated by said second means.
  • said second means comprises a heat exchanger formed of adjacent portions of said discharge and supply ducts whereby heat from said fluid when heated in said cooling element is transferred to fluid in said supply duct, which fluid then becomes less dense and flow thereof is restricted by said first means.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Details Of Measuring And Other Instruments (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Containers, Films, And Cooling For Superconductive Devices (AREA)
US455399A 1973-04-09 1974-03-27 Cooling system Expired - Lifetime US3908397A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7304884A NL7304884A (enrdf_load_stackoverflow) 1973-04-09 1973-04-09

Publications (1)

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US3908397A true US3908397A (en) 1975-09-30

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US455399A Expired - Lifetime US3908397A (en) 1973-04-09 1974-03-27 Cooling system

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US (1) US3908397A (enrdf_load_stackoverflow)
JP (1) JPS5219334B2 (enrdf_load_stackoverflow)
CA (1) CA997163A (enrdf_load_stackoverflow)
CH (1) CH569941A5 (enrdf_load_stackoverflow)
DE (1) DE2416423C2 (enrdf_load_stackoverflow)
FR (1) FR2224714B1 (enrdf_load_stackoverflow)
GB (1) GB1468745A (enrdf_load_stackoverflow)
NL (1) NL7304884A (enrdf_load_stackoverflow)
SE (1) SE397875B (enrdf_load_stackoverflow)

Cited By (3)

* 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
US7976770B1 (en) * 2005-07-29 2011-07-12 Hatch Ltd. Diagnostic system and method for metallurgical reactor cooling elements

Citations (1)

* 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

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB521792A (en) * 1938-09-28 1940-05-31 Eric Geertz Improved apparatus for handling liquid carbon dioxide
US2753691A (en) * 1951-09-15 1956-07-10 Chicago Bridge & Iron Co Method of cooling and storing propane and the like

Patent Citations (1)

* 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

Cited By (4)

* 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
US7976770B1 (en) * 2005-07-29 2011-07-12 Hatch Ltd. Diagnostic system and method for metallurgical reactor cooling elements
US8613883B2 (en) 2005-07-29 2013-12-24 Hatch Ltd. Diagnostic system and method for metallurgical reactor cooling elements

Also Published As

Publication number Publication date
GB1468745A (en) 1977-03-30
FR2224714B1 (enrdf_load_stackoverflow) 1977-10-21
SE397875B (sv) 1977-11-21
FR2224714A1 (enrdf_load_stackoverflow) 1974-10-31
CH569941A5 (enrdf_load_stackoverflow) 1975-11-28
DE2416423A1 (de) 1974-10-24
JPS5219334B2 (enrdf_load_stackoverflow) 1977-05-27
JPS49129941A (enrdf_load_stackoverflow) 1974-12-12
CA997163A (en) 1976-09-21
NL7304884A (enrdf_load_stackoverflow) 1974-10-11
DE2416423C2 (de) 1983-05-19

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