US3827252A - Method of regulation of the frigorific power of a joule-thomson refrigerator and a refrigerator utilizing said method - Google Patents

Method of regulation of the frigorific power of a joule-thomson refrigerator and a refrigerator utilizing said method Download PDF

Info

Publication number
US3827252A
US3827252A US00342672A US34267273A US3827252A US 3827252 A US3827252 A US 3827252A US 00342672 A US00342672 A US 00342672A US 34267273 A US34267273 A US 34267273A US 3827252 A US3827252 A US 3827252A
Authority
US
United States
Prior art keywords
expansion
passage
refrigerant fluid
refrigerator
section
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
US00342672A
Other languages
English (en)
Inventor
P Chovet
C Rollin
H Galasso
R Prost
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Air Liquide SA filed Critical Air Liquide SA
Application granted granted Critical
Publication of US3827252A publication Critical patent/US3827252A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • F25B9/02—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using Joule-Thompson effect; using vortex effect
    • 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
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/02—Gas cycle refrigeration machines using the Joule-Thompson effect
    • F25B2309/022—Gas cycle refrigeration machines using the Joule-Thompson effect characterised by the expansion element

Definitions

  • the invention relates to a method of and apparatus for [73] Assignee: lLAir Liquide, Somme A ny the regulation of the frigorific power supplied by a relPour LEtude Er LExploirari deg frigerator utilizing the Joule-Thomson expansion of a Procedes Georges Cla de, Pari refrigerant fluid at a temperature below its inversion France temperature, in which the flow-rate of the expanded refrigerant fluid is automatically re ulated in de en- [221 1973 dence on the frigorific output to bf supplied, an d is [21] Appl.
  • the refrigerator comprises an U-S- 14, expansion device consisting of an expansion rifice a 62/223 seating and a needle-valve, one of said two latter elellnt- Cl. 1 ments being fixed and the other movable and a Field 01fSearch 222, 1 56 temperature-responsive detection.
  • the regulation may be effected by proportional action 3,055,192 9/1962 Dennis 62/514 of y dirfict action, in the latter Case, the temperature 3 32 755 5 9 7 je 2 5 responsive regulation chamber being constituted by a 3.451730 7/1969 Berry 62/514 bellows member containing a charge of heat- 3,517,525 6/1970 Campbell 1. 62/514 expandable fluid. 3,590,597 7/1971 Campbell 62/514 3,640,091 2/1972 Buller 62 514 9 Clams, 7 Drawmg Figures PATENIEU AUG 6 I974 SHEET 1 OF 3 FIG.]
  • the present invention relates to a method of regulation of the effective refrigerating power delivered by a refrigerator utilizing the Joule-Thomson expansion of a refrigerant fluid from a high pressure to a low pressure, the said fluid being at a temperature lower than its inversion temperature.
  • the invention is also con cerned with a Joule-Thomson refrigerator enabling the method of regulation forming the object of the invention to be carried into effect.
  • Refrigerators of the Joule-Thomson type have been employed for several years in various applications, especially in maintaining cold for devices detecting electro-magnetic radiation.
  • a refrigerator of this kind comprises a heat exchanger including a first passage for the refrigerant fluid under high pressure, and a second passage for the said fluid under low pressure, in heat-exchange relation with each other; an expansion member, the upstream side of which communicates with the first passage; a chamber for the refrigerant fluid under low pressure, communicating with the downstream side of the expansion member and the second passage.
  • this latter is generally arranged on the outside of the chamber under low pressure of the refrigerator, in thermal contact with the metal wall of this latter facing the expansion member along the mean direction of ejection of the refrigerant fluid.
  • the refrigerant fluid in the gaseous state and at high pressure is cooled and at least partly liquefied by the Joule-Thomson expansion.
  • a liquid phase and a gaseous phase of the refrigerant fluid are cooled and at least partly liquefied by the Joule-Thomson expansion.
  • the thermal load is then maintained at a cold temperature level, substantially equal to the boiling point of the refrigerant fluid at low pressure.
  • the calorific power injected into the refrigerator may vary within certain limits, independently ofthe expanded flow-rate. This may be due to an intermittent evolution of heat from the thermal load to be cooled, or to variations of the surrounding temperature, external to the refrigerator.
  • Certain impurities of the refrigerant fluid utilized may be condensed at the level of the expansion de vice, thus causing an obstruction of this latter and resulting in a reduction of the frigorific power delivered.
  • the refrigerator is supplied with refrigerant fluid from a gaseous source of constant volume under high pressure
  • a substantially constant low pressure atmospheric pressure for example
  • the frigorific power delivered is greater than the nominal frigorific power, by reason of the very high pressure, whereas at the end of the stable operating period the frigorific power delivered is lower than the nominal frigorific power due to the lower high pressure.
  • refrigerant fluid is therefore wasted and the autonomy of the refrigerator is correspondingly reduced for a gaseous source of given volume.
  • the expansion device is capable in addition of adjusting the flow-rate of the refrigerant fluid and is provided for that purpose with a seating having an expansion orifice and a needlevalve defining, with the said orifice, an adjustable expansion passage for the refrigerant fluid, one of these two members being movable with respect to the other which is fixed.
  • the system of regulation chosen then effects the movement of the moving member of the expansion device in dependence on a detected quantity representing the discrepancy of the useful frigorific power delivered by the refrigerator, with respect to its nominal value.
  • the regulation systems employed may be of different types:
  • the system of regulation comprises a detection element responsive to temperature (for example a thermo-couple), mounted inside the refrigerator, in the expansion chamber of the refrigerant fluid, in heat-exchange relation with the circuit of the refrigerant fluid under low pressure obtained after expansion.
  • a detection element responsive to temperature for example a thermo-couple
  • the electricl signal obtained at the output of the thermo-couple representing the temperature detected depending on the instantaneous useful frigoritic power delivered, is transmitted to a measuring device outside the refrigerator.
  • the electric signal transmitted is algebraically added to a reference signal corresponding to the nominal frigorific power in order to obtain an error signal.
  • the error signal thus obtained is transmitted to an electro-pneumatic valve external to the refrigerator and finally operating the displacement of the moving member of the expansion device as a function of the detected temperature.
  • the regulation system is entirely disposed in the refrigerator, and comprises a regulation chamber responsive to temperature, containing a charge of a fluid expandable under the effect of tempera ture, consisting at least partly of a bellows having one extremity fixed while the other movable extremity actuates the displacement of the moving member of the expansion device, in heat exchange relation with the refrigerant fluid at the low pressure.
  • the position of the moving element of the expansion device is thus adjusted in dependence on the discrepancy of the net delivered frigorific power with respect to its nominal value, and this under the effect of the temperature reached by the detection element responsive to the temperature:
  • the quantity detected by the regulation system is generally a temperature (that reached by the detection element responsive to temperature, for example by the chamber of expandable fluid) depending on the frigorific power of the refrigerator.
  • the detection element is in heat-exchange relation, on the one hand with the expanded refrigerant fluid, that is to say with all or part of the circuit under low pressure of the said fluid from the downstream side of the expansion device (chamber under low pressure and second passage of the exchanger, in the case of the refrigerator previously specified), and on the other hand with the hot part of the refrigerator, in particular by heat conduction.
  • the temperature reached by the regulation member corresponds to the equilibrium between the flow of heat reaching the said device from the hot part of the refrigerator, and the flow of cold reaching the said device from the circuit under low pressure of the refrigerant fluid.
  • any variation of the frigorific power delivered, or of the calorific power injected, or both, is thus indicated by a variation of the temperature reached by the detection element.
  • the bellows is capable of being expanded and contracted in a housing substantially isolated from the lowpressure circuit of the expanded refrigerant fluid. In this case, under steady conditions, due to the total inertia of the regulation system (essentially thermal), it is impossible to stabilize the frigorific power delivered at a nominal value.
  • the expanded flow-rate of refrigerant fluid thus oscillates between a maximum flow-rate and a flow-rate substantially zero.
  • the period of the corresponding oscillations depend on the one hand on the thermal inertia and on the other hand on the mechanical inertia of the regulation system employed. In this connection, it must be observed that the heat exchange rate effected between the refrigerant fluid under low pressure and the sealed charge of expandable fluid, contained in the regulation chamber, is relatively low.
  • the regulation chamber containing the sealed charge of expandable fluid may be entirely defined by the wall of the bellows or partly defined by the wall of the bellows and additionally by the wall of the housing in which the bellows is mounted.
  • the regulation chamber may further comprise a bulb forming an appendice arranged at least partly beyond the expansion device with respect to the remainder of the chamber.
  • the said chamber may be partly transferred to a hot zone of the refrigerator, in which case another portion remains in a cold zone of this latter in the form of a bulb, or it may be entirely located in a cold zone of the refrigerator.
  • the moving extremity of the bellows actuates the displacement of the moving needle-valve of the expansion device.
  • the refrigerant fluid is expanded and condensed and is then separated into a liquid phase collected at the bottom of the chamber at low pressure, and a gaseous phase occupying the remainder of the said chamber, which thus implies operation of the refrigerator in a vertical position, and the production of a level of refrigerant fluid in liquid form.
  • the regulation chamber is always in heatexchange relation directly with the refrigerant fluid at the low pressure.
  • the regulation chamber in direct contact with the refrigerant fluid under the low pressure, there are provided in a first case in which the chamber is arranged in a housing separate from the main chamber at low'pressure, communication passages from the said main chamber towards the said chamber, pierced in the wall of the said housing, and in the second case for which the regulation chamber is separate from the main chamber under low pressure, by at least one part of its own wall, a bulb comstituting an appendice of the said chamber, arranged in the lowpressure chamber of the refrigerator.
  • the flow-rate thus oscillates, in an undamped manner, on each side of the nominal flowrate, that is to say between a zero flow-rate and a maximum flow-rate.
  • the period of the oscillations is less than the period of the oscillations of the flow-rate obtained for a refrigerator in accordance with the previous proposal.
  • the total inertia of the regulation system is smaller.
  • the amplitude of the oscillations that is to say the upper limit (maximum flow-rate) of the expanded flow is very large, due to the nature of the expandable fluid chosen for filling the regulation chamber.
  • it is chosen to fill the regulation chamber with a fluid identical with the refrigerant fluid (nitrogen for example) or a fluid such as methane, the boiling point of which at the pressure existing under steady operating conditions in the expansion chamber, is at least equal to the boiling point of the refrigerant fluid at the low pressure of the refrigerator.
  • the quantity detected in order to regulate the frigorific power delivered corresponds in fact to the measurement of the level of the liquid phase of the refrigerant fluid in the chamber under low pressure.
  • a refrigerator according to the second proposal thus has a regulation of the expanded flow-rate of the on/off type characterized by a very short period or a high frequency and oscillations of large amplitude.
  • the present invention thus proposes to define a new method of regulation of a Joule-Thomson refrigerator which makes it possible to overcome the disadvantages of the regulation systems discussed above. More precisely, the invention proposes to define a method of regulation different from the method of regulation by on/off of the expanded flow-rate, and reducing substantially the oscillations of the expanded flow.
  • the conception of the system and method of regulation according to the invention is characterized by the fact that by means of the system of regulation chosen, the flow-rate of the expanded refrigerant fluid is automatically adjusted, above a minimum flow-rate other than zero corresponding to the minimum frigorific power which is to be delivered under steady conditions by the expansion of the refrigerant fluid in order to compensate for the heat losses of the refrigerator under those conditions.
  • regulation system there is meant according to the present invention, the regulation systems previously considered, whether they are of the indirect or direct action type, and whether the quantity detected in order to correct the flow-rate of the expanded refrigerant fluid is the level of the refrigerant fluid in the liquid form in the expansion chamber of the refrigerator, or the temperature existing in the cold zone of the exchanger of the refrigerator, or any other significant quantity of the variations of the useful frigorific power delivered.
  • the heat losses of the refrigerator in steady operation may be easily evaluated by calculation or experiment, for example by filling the expansion chamber with a given quantity of the refrigerant fluid in liquid form and measuring as a function of time the quantity of refrigerant fluid in the gaseous form escaping from the refrigerator.
  • the expanded flowrate is constantly regulated above this rate of flow.
  • minimum flow-rate there is thus meant a flowrate of expanded refrigerant fluid permitting the compensation under steady operation of the heat losses of the refrigerator.
  • This flow-rate does not necessarily remain constant; it is for example capable of varying as a function of variations in the rate of expansion of the refrigerant fluid.
  • to a reduction of the high pressure there will correspond an increase of the minimum flow-rate.
  • a system of regulation functioning according to the invention may carry out its action under two conditions of operation:
  • the system of regulation adjusts in a corresponding manner the flow-rate of the expanded refrigerant fluid between the minimum flow-rate and an initial flow-rate higher than the minimum flow.
  • the minimum flow-rate corresponds to a so-called minimum position of the moving element of the expansion device, in which the total section of passage of the refrigerant fluid through the expansion device is a minimum.
  • the regulation of the expanded flow-rate is thus of the all-or-little type.
  • the disadvantages previously indicated, associated with a regulation of the on/off type are eliminated. Irrespective of the period of the oscillations of the regulated flow-rate, or the amplitude of these oscillations, and whatever may be the conditions of operation of the re frigerator, a minimum frigorific power, guaranteeing the maintenance of the cold reference temperature of the refrigerator is always ensured under steady operating conditions.
  • the invention has the following preferred procedure.
  • the nature of the expandable fluid is chosen in such manner that this latter remains gaseous at the boiling temperature of the refrigerant fluid at the low pressure.
  • the expandable fluid is chosen from hydrogen, helium, neon, and mixtures of these gases.
  • the expandable fluid there is utilized as the expandable fluid a gas which is non-condensable at the nominal working temperature of the refrigerator.
  • the regulation chamber then behaves in operation like a gas thermometer and not like a vapour tension bulb, as shown by the state of the art.
  • the choice of a gas as the expandable fluid for the regulation chamber makes it possible to reduce substantially the amplitude of the oscillations of the expanded flow-rate.
  • the regulation chamber has a greater heat inertia than in the case of a filling with a gas-liquid mixture (vapour-tension bulb); the coefficient of internal exchange utilized is lower than in the previous case.
  • the total minimum section of the passage through the expansion device, of the first passage of the exchanger towards the expansion chamber is not zero. It is preferably equal to at least 2 percent of the section of the orifice of the seating of the expansion device.
  • This minimum total section may be represented by a calibrated leakage passage.
  • the regulation chamber may be formed entirely by the wall of the bellows or partly formed by the wall of this latter and additionally by the wall of the housing in which the bellows is arranged.
  • FIG. I represents a view in longitudinal section of the cold portion of a Joule-Thomson refrigerator according to the invention.
  • FIG. 2 represents a view in cross-section taken along the line Il-II of FIG. ll, of the same refrigerator;
  • FIG. 3 represents a view in crosssection, taken along the line III-III of FIG. I, of the same refrigerator;
  • FIG. 4- represents diagrammatically the expansion device of the refrigerator shown in FIGS. l to 3, and illustrates a method of regulation of the expanded flow-rate in the said device, according to the invention
  • FIG. 5 shows diagrammatically another expansion device according to the invention, and illustrates a method of regulation of the expanded flow-rate according to the invention
  • FIG. 6 shows diagrammatically a further expansion device according to the invention, and illustrates a method of regulation of the expanded flow-rate according to the invention
  • FIG. 7 shows graphically the variations of the flowrate Q of the refrigerant fluid expanded, as a function of the time t. The curve shown indicates these variations for a refrigerator having its flow-rate regulated according to the invention, as described with reference to FIGS. d to 6.
  • the Joule-Thomson refrigerator shown in accordance with FIGS. I to 3 comprises a heat-exchanger 1, an expansion device 2, a regulation system 3, arranged in the interior of a heat-insulating wall 4 comprising an internal wall 5 and an external wall 6 between which a vacuum has been created.
  • the heat-exchanger 1 comprises a tube 50 of great length, arranged in the form of a coil between the cylindrical inner wall 5 and a cylindrical casing 7, and constituting a first passage for a refrigerant fluid under high pressure.
  • the expansion device 2 capable of adjusting the flow-rate of the expanded refrigerant fluid, comprises a fixed seating 9 of stainless steel provided with an expansion orifce Ill and a moving needle-valve lltl defining with the said orifice 11, an expansion passage for the refrigerant fluid.
  • the needle-valve It ⁇ is constituted by a sapphire stuck on a metal piece.
  • the seating 9 comprises a channel 12, the upstream side of which communicates with the first passage 50 of the exchanger 1, while the downstream side communicates with the expansion orifice ill.
  • the seating 9 is fixed to a collar 13 by means of a pin M; the collar 13 is itself fixed by welding to one extremity of the cylindrical casing 7. There exists however a certain play between the pin 14 and the seating 9 in order to permit a self-centering action of the needle-valve it) inside the seating 9.
  • the needle-valve 10 is fixed on a perforated plug 15 engaged inside and at one extremity of a movable split tube 16.
  • the internal space formed by the inner wall 5 is therefore partly occupied by the exchanger l and the expansion device 2.
  • the remaining portion constitutes a chamber 17 for the refrigerant fluid under low pressure, communicating with the downstream side of the expansion orifice Ill and the second passage 8 of the exchanger 1, as previously defined.
  • a thermal load 18 constituting the sensitive portion of a detector of electro-magnetic radiation is fixed to the exterior of the inner wall 5, in thermal contact with this latter, opposite the expansion device 2, in the mean direction of ejection of the refrigerant fluid out of the expansion orifice Ill.
  • the direct-action regulation system 3 comprises a regulation chamber 19 sensitive to the temperature, defined by a bellows 20. As will be seen below, in operation this chamber constitutes, as for an indirect action regulation system, the detection element of a temperature representing the useful frigorific power delivered by the refrigerator.
  • the chamber 119 is in heat-exchange relation, on the one hand with the circuit of the refrigerant fluid under low pressure (chamber 17 and the second passage 8 of the exchanger I), and more particularly with the cold portion of the second passage of the heat-exchanger 2, and on the other hand with the hot part of the refrigerator by thermal conduction.
  • One extremity of the bellows 2 1) is fixed and con nected to a cylindrical member 21 arranged inside the casing 5, and the other extremity of which is movable and is connected to a block 22 fixed to the split tube 16.
  • the moving extremity of the bellows 20, rigidily fixed to the block 22, thus controls the movement of the needle-valve 10 of the expansion device 2, through the intermediary of the split tube 16 sliding on each side of the guiding pin 14.
  • the chamber 19 contains a sealed charge of a fluid expandable under the effect of temperature, introduced into the bellows 20, by means of a tube 23 passing through the member 21.
  • a sealed charge of a fluid expandable under the effect of temperature introduced into the bellows 20, by means of a tube 23 passing through the member 21.
  • the nature of this charge is determined in dependence on the refrigerant fluid chosen, on the low-pressure existing in the expansion chamber, in such manner that this charge will remain gaseous during operation.
  • the expandable fluid is chosen from the group consisting of helium, hydrogen, neon, or a mixture of these gases.
  • the cylindrical casing 7, the collar 3 and the member 21 define a compartment enclosing the bellows 20, substantially insulated from the chamber 17 under low pressure.
  • the needle-valve it) and the seating 9 are accurately centered with respect to each other by virtue of the sliding of the split tube 16 on each side of the pin 14;
  • a suitable refrigerant fluid nitrogen for example
  • a suitable refrigerant fluid circulates in the first passage or the conduit 50 of the exchanger 1 and is cooled to a low temperature. It is then expanded at low pressure in the expansion device 2, and the flow-rate of expanded refrigerant fluid delivers the frigorific power necessary to compensate at least for the calorific power injected into the refrigerator.
  • the refrigerant fluid is at least partly liquefied by expansion from the high pressure to the low pressure
  • the presence of the refrigerant fluid at low pressure enables a cold reference temperature to be maintained in the chamber 17 which is substantially constant and equal to the boiling point of the refrigerant fluid employed at the said pressure.
  • the charge 18, in heat-exchange relation with the said fluid, is therefore maintained at a substantially constant cold temperature.
  • the vaporized refrigerant fluid at low pressure then circulates in the second passage 8 of the exchanger 1, in which it is heated by heat-exchange with the refrigerant fluid at high pressure, in course of cooling in the first passage 50.
  • the regulation system 3 employed, or more particularly the expandable chamber 19 is subjected on the one hand to an additional supply of heat coming from the hot part of the refrigerator, and on the other hand to a supply of cold coming from the immediate and cold surroundings of the said device, that is to say from the circuit under low pressure of the expanded refrigerant fluid (chamber 17 and second passage 8 of the exchanger 1).
  • the regulation chamber 19 is therefore brought to an intermediate temperature, higher than the boiling point of the refrigerant fluid at the low pressure, correspond ing to an equilibrium between the calorific and frigorific fluxes which reach the chamber 19.
  • the calorific flux generally remains substantially constant, while on the other hand the frigorific flux varies in dependence on the variations in the liquid-gas proportion of the refrigerant fluid under low pressure, collected in the chamber 17.
  • the variations of the temperature of the said device thus follow the variations of useful frigoriflc power delivered.
  • the chamber 19 contains a sealed charge of a gas which is expandable under the effect of temperature, it is therefore possible to effect a direct-action regulation of the useful frigorific power delivered, as a function of the temperature obtained at the level of the regulation system, and more precisely an automatic adjustment of the expanded flow-rate in dependence on the said temperature.
  • the operation of the regulation capacity as a gas thermometer makes it possible to obtain a linear relation between the temperature detected by the regulation chamber 19 and the displacement of the moving element of the expansion device (needle-valve 10). As by construction there exists a linear relation between this displacement and the flow-rate of expanded refrigerant fluid, there may thus be obtained a servo-control of the useful frigorific power delivered to the temperature detected by the regulation system.
  • the minimum frigorific power which is to be delivered under steady operating conditions by the expansion of the refrigerant fluid in order to compensate for the heat losses of the refrigerator under those conditions, is shown by the minimum flow-rate QMIN.
  • This flow-rate is not necessarily constant, as has been previously indicated, especially if the rate of expansion of the refrigerant fluid varies with time.
  • the flow-rate QMIN corresponds to the minimum position 24 of the needlevalve 10 (see FIG. 4), in which the total section of passage of the refrigerant fluid through the expansion device is a minimum but not zero.
  • the refrigerator according to the invention is working under the transient conditions of starting-up.
  • the useful frigorific power delivered varies automatically from an initial useful frigorific power delivered by the intitial flowrate QI, greater than the minimum frigorific power delivered by the flow-rate QMIN, to the nominal useful frigorific power of the refrigerator, delivered by the nominal flow-rate ON.
  • the initial flow-rate 01 corresponds to the frigorific power delivered during the starting-up of the refrigerator, when the needle-valve 10 is in the intitial position 26 (see FIG. 4), that is to say when this latter liberates the full section of the expansion orifice.
  • the flow-rate of the expanded refrigerant fluid is thus caused to vary automatically between the initial flow-rate 01 for which the temperature of the regulation chamber 19 is the ambient temperature, and the nominal flow-rate QN for which the regulation chamber is at a temperature close to but higher than the nominal temperature of operation of the refrigerator (77K for example).
  • the refrigerator according to the invention operates under steady conditions. From the instantT, the frigorific power delivered is maintained at its nominal value, by virtue of the regula tion system employed. Correspondingly, as a function of the disturbances caused in the operation of the refrigerator (variations of the rate of expansion for exam ple), the flow-rate of expanded refrigerant fluid is automatically adjusted regulated to a nominal value QN greater than the minimum flow-rate QMIN previously defined.
  • the flow-rate ON corresponds to the nominal position 70 of the needle'valve in which the total nominal section of the expansion passage is greater than the total minimum section of passage previously defined.
  • the expanded flow-rate Due to the thermal inertia of the regulation system the expanded flow-rate is not stabilized at its nominal value but continually oscillates about that value, that is to say between an upper limit (maximum flow-rate QMAX) and a lower limit.
  • the minimum flow-rate QMIN there is chosen as the lower limit of the oscillations of the flow-rate, the minimum flow-rate QMIN previously defined, corresponding to the minimum frigorific power of the refrigerator.
  • the expanded flow-rate is continuously adjusted above this flow-rate QMIN which is a minimum but not zero.
  • the volume of the regulation chamber is automatically regulated under continuous steady conditions and under the effect of the temperature reached by the expandable fluid, in dependence on the frigorific power to be delivered. More precisely, this volume is automatically adjusted between:
  • This maximum total section of passage is lower under steady conditions than the initial total section of passage of the refrigerant fluid through the expansion desteady operating conditions, for refrigerators of the state of the art, the nominal frigorific power is maintained at a value substantially equal to the minimum frigorific power contemplated by the present invention.
  • the expanded flow-rate is automatically regulated to a nominal value substantially equal to the minimum flow-rate QMIN shown in FIG. 7.
  • the flow-rate oscillates continually about the nominal flowrate QMIN, whereas for the refrigerator according to the invention, it oscillates continually about a nominal flow-rate QN greater than the flow-rate QMIN.
  • the minimum flow-rate QMIN is always greater than the residual! leakage flow e which is substantially zero, resulting from imperfections of construction of the expansion device 2, flowing away when the needle-valve l0 completely closes the expansion orifice 111 in order to annul the useful section of the expansion passage between the needle-valve I0 and the orifice Ill.
  • the frigorific power delivered is always in excess of the frigorific power strictly required. However, this does not result in a very large excess consumption of refrigerant fluid.
  • the nominal flow-rate QN (representing the mean expanded flow-rate) is very little higher than the minimum flow-rate QMIN.
  • the result according to the invention is to facilitate a very good thermal efficiency of the exchanger of the refrigerator (the expanded flow-rate is not regulated by all-or-nothing) while consuming a. flow-rate of refrigerant fluid which is very close to that of refrigerators of the prior art.
  • the autonomy of a Joule- Thomson refrigerator is considerably improved.
  • the minimum section of passage through the expansion device is substantially equal to the minimum useful section of the expansion passage, existing between the needle-valve l0 and the expansion orifice lll when the needle-valve I0 is in the minimum position 24.
  • the whole of the minimum flow-rate QMIN is thus expanded through the said minimum useful section.
  • it is possible to act at the level of the expansion device by regulating either the position of the needle-valve 10 with respect to its supporting plug 15, or the position of the seating 9. Action can then be taken at the level of the regulation device, either by regulating the position of the fixed extremity of the bellows (part 21), for example from the hot part of the refrigerator, or by regulating the characteristics of the expandable chamber 19.
  • either the elasticity of the bellows 20 may be suitably chosen (choice of the constituent material and its dimensions), or action may be taken on the characteristics of the sealed charge of the expandable fluid (by choosing for example a suitable filling pressure for the gas chosen as the: expandable fluid).
  • the minimum corresponding useful section of the expansion passage is substantially zero.
  • the whole of the minimum flow-rate QMIN is therefore expanded through a calibrated passage 28.
  • the expansion device comprises a calibrated leakage passage 28, located as shown in FIG. 5 in the seating 9 of the expansion device or located, as shown in FIG. 6, in the needle-valve 10 of the expansion device.
  • the section of the leakage passage 28 is substantially equal to the total minimum section previously referred to.
  • the minimum total section previously defined is comprised between 2 and 5% of the section of the expansion orifice 11.
  • a Joule-Thomson refrigerator for the isenthalpic expansion of a refrigerant fluid at a temperature below the inversion temperature thereof, from a high pressure to a low pressure comprising:
  • a heat-exchanger including a first passage for said fluid under high pressure, and a second passage for said fluid under low pressure, in heat-exchange relation with one another,
  • an expansion device to adjust the flow rate of the expanded refrigerant fluid, the upstream side of which is in fluid communication with said first passage, said expansion device comprising a seating having an expansion orifice, and a needle valve defining with said expansion orifice an adjustable expansion passage for said refrigerant fluid, one of said seating and said needle valve being movable in a longitudinal direction while the other remains fixed,
  • direct-action regulating means comprising a temperature-responsive regulation chamber containing a charge of fluid expandable under the effect of temperature, at least partly in heat-exchange relation with at least part of the low-pressure circuit of said refrigerant fluid, a bellows member comprising at least part of a wall of said chamber and extending in said longitudinal direction, one extremity of which is fixed, whereas the other extremity is movable along said longitudinal direction and actuates the movable element of said expansion device in said longitudinal direction,
  • said expandable fluid being at least one member selected from the group consisting of hydrogen, helium and neon.
  • a refrigerator according to claim ll wherein at least one of said regulating means and said expansion means adjusts the total expansion section through said expansion device, from said first passage toward said reception chamber, above a minimum expansion section, different from a substantially zero section.
  • a Joule-Thomson refrigerator for the isenthalpic expansion of a refrigerant fluid at a temperature below the inversion temperature thereof, from a high pressure to a low pressure comprising:
  • a heat-exchanger including a first passage for said fluid under high pressure, and a second passage for said fluid under low pressure, in heat-exchange relation with one another,
  • an expansion device to adjust the flow rate of the expanded refrigerant fluid, the upstream side of which is in fluid communication with said first passage, said expansion device comprising a seating having an expansion orifice, and a needle valve defining with said expansion orifice an adjustable expansion passage for said refrigerant fluid, one of said seating and said needle valve being movable in a longitudinal direction while the other remains fixed,
  • regulating means comprising a temperatureresponsive detection element at least partly in heatexchange relation with at least part of the lowpressure circuit of said refrigerant fluid, for moving the movable element of said expansion device in said longitudinal direction in response to the temperature detected by said detection element,
  • At least one of said regulating means and said expansion means adjusting the total expansion section through said expansion device, from said first passage toward said reception chamber, above a minimum expansion section, different from a substantially zero section.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Temperature-Responsive Valves (AREA)
US00342672A 1972-03-23 1973-03-19 Method of regulation of the frigorific power of a joule-thomson refrigerator and a refrigerator utilizing said method Expired - Lifetime US3827252A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7210139A FR2176544B1 (enrdf_load_stackoverflow) 1972-03-23 1972-03-23

Publications (1)

Publication Number Publication Date
US3827252A true US3827252A (en) 1974-08-06

Family

ID=9095674

Family Applications (1)

Application Number Title Priority Date Filing Date
US00342672A Expired - Lifetime US3827252A (en) 1972-03-23 1973-03-19 Method of regulation of the frigorific power of a joule-thomson refrigerator and a refrigerator utilizing said method

Country Status (5)

Country Link
US (1) US3827252A (enrdf_load_stackoverflow)
JP (1) JPS4935940A (enrdf_load_stackoverflow)
DE (1) DE2314003A1 (enrdf_load_stackoverflow)
FR (1) FR2176544B1 (enrdf_load_stackoverflow)
GB (1) GB1431333A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4080802A (en) * 1976-07-14 1978-03-28 International Telephone And Telegraph Corporation Hybrid gas cryogenic cooler
US4236518A (en) * 1978-04-14 1980-12-02 Gyne-Tech Instrument Corporation Cryogenic device selectively operable in a continuous freezing mode, a continuous thawing mode or a combination thereof
US4237699A (en) * 1979-05-23 1980-12-09 Air Products And Chemicals, Inc. Variable flow cryostat with dual orifice
US4569210A (en) * 1984-07-30 1986-02-11 Societe Anonyme De Telecommunications Cooling controller utilizing the Joule-Thomson effect
US4570457A (en) * 1984-01-26 1986-02-18 The Hymatic Engineering Company Limited Cryogenic cooling apparatus
US4631928A (en) * 1985-10-31 1986-12-30 General Pneumatics Corporation Joule-Thomson apparatus with temperature sensitive annular expansion passageway
US5548963A (en) * 1995-06-08 1996-08-27 Hughes Missile Systems Company Joule-Thompson cryostat for use with multiple coolants
US5595065A (en) * 1995-07-07 1997-01-21 Apd Cryogenics Closed cycle cryogenic refrigeration system with automatic variable flow area throttling device
US20170370638A1 (en) * 2016-06-24 2017-12-28 Universidad De Zaragoza System and method for improving the liquefaction rate in cryocooler-based cryogen gas liquifiers
CN110142546A (zh) * 2019-05-15 2019-08-20 中国电子科技集团公司第十一研究所 使用膜片弹簧的波纹管型j-t制冷器自调机构装配夹具
CN110274404A (zh) * 2019-05-15 2019-09-24 中国电子科技集团公司第十一研究所 波纹管型自调式j-t制冷器

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2520131B1 (fr) * 1982-01-19 1985-09-20 Telecommunications Sa Dispositif de regulation d'un refrigerateur a effet joule-thomson
FR2598206B1 (fr) * 1986-05-05 1988-07-08 Air Liquide Refroidisseur joule-thomson.
FR2599128A1 (fr) * 1986-05-26 1987-11-27 Air Liquide Procede d'alimentation d'un refroidisseur joule-thomson et appareil de refroidissement pour sa mise en oeuvre
FR2645256B1 (fr) * 1989-03-15 1994-12-23 Air Liquide Refroidisseur joule-thomson a deux debits
GB2247517B (en) * 1990-08-07 1994-01-26 Hymatic Eng Co Ltd Cryogenic cooling apparatus

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3055192A (en) * 1960-12-01 1962-09-25 Specialties Dev Corp Cooling apparatus
US3320755A (en) * 1965-11-08 1967-05-23 Air Prod & Chem Cryogenic refrigeration system
US3457730A (en) * 1967-10-02 1969-07-29 Hughes Aircraft Co Throttling valve employing the joule-thomson effect
US3517525A (en) * 1967-06-28 1970-06-30 Hymatic Eng Co Ltd Cooling apparatus employing the joule-thomson effect
US3590597A (en) * 1968-08-06 1971-07-06 Hymatic Eng Co Ltd Cooling apparatus employing the joule-thomson effect
US3640091A (en) * 1969-05-13 1972-02-08 Santa Barbara Res Center Valve arrangement to provide temperature level control at cryogenic temperature ranges
US3704597A (en) * 1969-12-08 1972-12-05 Hymatic Eng Co Ltd Cooling apparatus
US3704598A (en) * 1969-03-25 1972-12-05 Hymatic Eng Co Ltd Cryogenic cooling apparatus
US3728868A (en) * 1971-12-06 1973-04-24 Air Prod & Chem Cryogenic refrigeration system
US3747365A (en) * 1970-02-18 1973-07-24 Hymatic Eng Co Ltd Cryogenic cooling apparatus

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3055192A (en) * 1960-12-01 1962-09-25 Specialties Dev Corp Cooling apparatus
US3320755A (en) * 1965-11-08 1967-05-23 Air Prod & Chem Cryogenic refrigeration system
US3517525A (en) * 1967-06-28 1970-06-30 Hymatic Eng Co Ltd Cooling apparatus employing the joule-thomson effect
US3457730A (en) * 1967-10-02 1969-07-29 Hughes Aircraft Co Throttling valve employing the joule-thomson effect
US3590597A (en) * 1968-08-06 1971-07-06 Hymatic Eng Co Ltd Cooling apparatus employing the joule-thomson effect
US3704598A (en) * 1969-03-25 1972-12-05 Hymatic Eng Co Ltd Cryogenic cooling apparatus
US3640091A (en) * 1969-05-13 1972-02-08 Santa Barbara Res Center Valve arrangement to provide temperature level control at cryogenic temperature ranges
US3704597A (en) * 1969-12-08 1972-12-05 Hymatic Eng Co Ltd Cooling apparatus
US3747365A (en) * 1970-02-18 1973-07-24 Hymatic Eng Co Ltd Cryogenic cooling apparatus
US3728868A (en) * 1971-12-06 1973-04-24 Air Prod & Chem Cryogenic refrigeration system

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4080802A (en) * 1976-07-14 1978-03-28 International Telephone And Telegraph Corporation Hybrid gas cryogenic cooler
US4236518A (en) * 1978-04-14 1980-12-02 Gyne-Tech Instrument Corporation Cryogenic device selectively operable in a continuous freezing mode, a continuous thawing mode or a combination thereof
US4237699A (en) * 1979-05-23 1980-12-09 Air Products And Chemicals, Inc. Variable flow cryostat with dual orifice
EP0020111A3 (en) * 1979-05-23 1981-02-11 Air Products And Chemicals, Inc. Cryogenic refrigerators, arrangement incorporating such cryogenic refrigerators and system incorporating such cryogenic refrigerators
US4570457A (en) * 1984-01-26 1986-02-18 The Hymatic Engineering Company Limited Cryogenic cooling apparatus
US4569210A (en) * 1984-07-30 1986-02-11 Societe Anonyme De Telecommunications Cooling controller utilizing the Joule-Thomson effect
US4631928A (en) * 1985-10-31 1986-12-30 General Pneumatics Corporation Joule-Thomson apparatus with temperature sensitive annular expansion passageway
WO1987002798A1 (en) * 1985-10-31 1987-05-07 General Pneumatics Corporation Joule-thomson apparatus with temperature sensitive annular expansion passageway
US4738122A (en) * 1985-10-31 1988-04-19 General Pneumatics Corporation Refrigerant expansion device with means for capturing condensed contaminants to prevent blockage
US5548963A (en) * 1995-06-08 1996-08-27 Hughes Missile Systems Company Joule-Thompson cryostat for use with multiple coolants
US5595065A (en) * 1995-07-07 1997-01-21 Apd Cryogenics Closed cycle cryogenic refrigeration system with automatic variable flow area throttling device
US20170370638A1 (en) * 2016-06-24 2017-12-28 Universidad De Zaragoza System and method for improving the liquefaction rate in cryocooler-based cryogen gas liquifiers
CN110142546A (zh) * 2019-05-15 2019-08-20 中国电子科技集团公司第十一研究所 使用膜片弹簧的波纹管型j-t制冷器自调机构装配夹具
CN110274404A (zh) * 2019-05-15 2019-09-24 中国电子科技集团公司第十一研究所 波纹管型自调式j-t制冷器

Also Published As

Publication number Publication date
GB1431333A (en) 1976-04-07
JPS4935940A (enrdf_load_stackoverflow) 1974-04-03
FR2176544B1 (enrdf_load_stackoverflow) 1982-02-19
FR2176544A1 (enrdf_load_stackoverflow) 1973-11-02
DE2314003A1 (de) 1973-10-04

Similar Documents

Publication Publication Date Title
US3827252A (en) Method of regulation of the frigorific power of a joule-thomson refrigerator and a refrigerator utilizing said method
US5119637A (en) Ultra-high temperature stability Joule-Thomson cooler with capability to accommodate pressure variations
US7415836B2 (en) Cooling apparatus and a thermostat with the apparatus installed therein
US5195331A (en) Method of using a thermal expansion valve device, evaporator and flow control means assembly and refrigerating machine
US3457730A (en) Throttling valve employing the joule-thomson effect
US4002039A (en) Self-regulating cryostat
US3687365A (en) Thermostatic flow controller
US3728868A (en) Cryogenic refrigeration system
US4177650A (en) Cryogenic cooling apparatus
US5293750A (en) Control system for liquefied gas container
US3667246A (en) Method and apparatus for precise temperature control
US3640091A (en) Valve arrangement to provide temperature level control at cryogenic temperature ranges
US3590597A (en) Cooling apparatus employing the joule-thomson effect
US4479367A (en) Thermal filter
US4569210A (en) Cooling controller utilizing the Joule-Thomson effect
US5181386A (en) Cryogenic cooling apparatus
US4381652A (en) Demand flow cryostat
US5913889A (en) Fast response Joule-Thomson cryostat
US3910064A (en) Method and apparatus for producing variable temperature with the aid of a cryoliquid
US3427815A (en) Cryogenic temperaure control
JPS6021730Y2 (ja) 低温度恒温装置
EP0815402B1 (en) Cooler
US5548963A (en) Joule-Thompson cryostat for use with multiple coolants
US5313801A (en) Cryostat throttle
Hedegard et al. A NON-CU) GGING, TEMPERATURE-SENSITIVE, CLOSED-CYCLE LINDE-HAMPSON CRYOCOOLER