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US20100192623A1 - Refrigeration circuit - Google Patents

Refrigeration circuit Download PDF

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Publication number
US20100192623A1
US20100192623A1 US12/669,004 US66900408A US2010192623A1 US 20100192623 A1 US20100192623 A1 US 20100192623A1 US 66900408 A US66900408 A US 66900408A US 2010192623 A1 US2010192623 A1 US 2010192623A1
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United States
Prior art keywords
tubing
tube
exchanger
cooling fluid
circuit
Prior art date
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Abandoned
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US12/669,004
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English (en)
Inventor
Paolo Cittadini
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Industrie Ilpea SpA
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Industrie Ilpea SpA
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Assigned to INDUSTRIE ILPEA S.P.A. reassignment INDUSTRIE ILPEA S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CITTADINI, PAOLO
Publication of US20100192623A1 publication Critical patent/US20100192623A1/en
Abandoned legal-status Critical Current

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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
    • F25B39/00—Evaporators; Condensers
    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/08—Tubular elements crimped or corrugated in longitudinal section
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
    • F28F21/062—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material the heat-exchange apparatus employing tubular conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/0246—Arrangements for connecting header boxes with flow lines

Definitions

  • the present invention relates to a refrigeration circuit.
  • the present invention relates to a refrigerating apparatus, preferably of the type used in household appliances such as refrigerators, freezers, deep-freezers, iceboxes and the like.
  • the invention is likewise and also applicable, in a totally similar manner, also to household appliances for conditioning.
  • refrigerators of the traditional type and similar refrigerating apparatus comprise a refrigeration circuit wherein a refrigerating means is used suitable for subtracting heat from a closed space to be cooled to a predetermined temperature, such as the interior of the refrigerator or freezer, transferring it towards the outer warmer space.
  • the above refrigeration circuit is a closed circuit wherein a compressor, a condenser, a lamination or capillary device and an evaporator operate in a sequence according to known operating modes.
  • the refrigerating means is a low boiling point substance suitable for undergoing a passage of state from liquid to vapour by expansion with the effect of subtracting heat to the ambient it is in contact with, and afterwards a reverse passage from vapour to liquid, during the circulation thereof within the refrigeration circuit.
  • the metal coils used for such function are generally obtained starting from a continuous metal tube (steel, aluminium or copper) which is suitably bent multiple times for following a profile of a useful surface intended for thermal exchange.
  • a useful surface is located at the back of the refrigerator in the case of the condenser, whereas in the case of the evaporator, the arrangement of the coils depends on the model of refrigerating apparatus or refrigerator, freezer or combined, and it concerns one or more walls inside the refrigerator itself. In particular, it is known to position the coil of the evaporator at the inside bottom wall and/or at the inside side walls of the refrigerator, or even at one or more shelves provided inside the refrigerator.
  • the evaporators may be static (Wire On Tubes or Tubes On Plates) or dynamic (No Frost).
  • a pack consisting of steel or aluminium or copper tubes suitably bent and welded or otherwise connected to other metal bodies that increase the exchange surface thereof (metal wires in the case of WOT, metal sheets in the case of TOP and aluminium sheets in the case of NF).
  • the bending of the metal tube for making the evaporator coil is carried out according to different methods depending on the geometry of the surface whereon the coil itself is intended to be active.
  • the bending of the metal tube is generally carried out by special tube bending machines prior to the final installation of the coil, and it must therefore be arranged in a differentiated manner according to the final geometry of the coil. The bending must be made so as to prevent chocking or section variations in such zones.
  • the storage processes are damaged as they must provide for the storage of different types of coils, each intended to be mounted only on predetermined thermal exchange surfaces having predetermined geometry.
  • the manufacture of the above coils starting from metal tubes implies further production costs related to the procurement of raw materials (metal), to any processing of raw materials themselves, as well as to the complex operations for manufacturing the metal tube and the bending thereof for defining the end profile of the coil.
  • the metal tube is obtained by welding a suitable formed flat sheet, and such process is very expensive and complex, as it must also be carried out in an accurate manner to prevent leaks of cooling fluid which would irreparably damage the refrigerator in very short times, with serious economic consequences for the manufacturer and for the environment (such fluids are often polluting).
  • the metal tube is supplied in rolls to the manufacturers of evaporators and is thus unrolled, straightened, the diameter thereof is checked and then it is suitably bent multiple times at 180° in alternating direction to obtain the desired thermal exchange surface, and finally coupled to metal bodies shaped as fins or straight metal wires, suitable for facilitating the thermal exchange with the ambient to be cooled.
  • the coupling with such metal wires is mostly made by spot welding (WOT) or by the introduction of the tube bundle into special slits obtained in the aluminium fins (NF).
  • a refrigerator comprising an evaporator equipped with a flexible tube.
  • the flexible tube made of plastic material, is cylindrical and wound spiral-wise around respective supports and can be elongated or packed for varying its configuration based on a part of the refrigerator wherein a cooling action is desired.
  • the flexibility of the tube is limited and the same may be deformed substantially along a single direction around which the coils are wound.
  • a refrigerator is known from patent KR 20010094016 provided with an evaporator made of plastic material.
  • such evaporator (with rigid structure and shaped as a flat surface defining the cooling tubes and the fins) exhibits a coating of electrically conductive paste to be connected to an external metal conductor and a further external insulating layer of plastic as well.
  • the adoption of a similar plastic tube having perfectly cylindrical shape does not allow optimum thermal exchange by the cooling fluid circulating therein.
  • the above cylindrical tube wound spiral-wise is suitable for being elongated or packed along a predetermined direction, however it does not exhibit high properties of flexibility in any direction, and in particular in the case of very marked bending such as narrow radius bending generally required in making flat coils for refrigerators.
  • the above patent also refers to the making of a layer of conductive material comprised between an internal plastic material in contact with the cooling fluid and an external coating material the nature and application technology whereof are absolutely not described.
  • a cover is provided outside the tubes of plastic material, consisting of synthetic fibres in turn protected by a further outer sheath.
  • the tube described in the above European patent exclusively serves for carrying such fluid and not for a thermal exchange with the ambient, which takes place in different and not described structures.
  • tubing of plastic material for heat exchangers is known for applications totally different from refrigeration circuits for household appliances.
  • heat exchangers are designed for the most varied applications in the automotive field.
  • exchangers are known according to patent US2007/0289725 and U.S. Pat. No. 5,706,864.
  • the technical task of the present invention is to provide a refrigeration circuit and household appliance which should be free from the drawback mentioned above.
  • an object of the invention is to provide a household appliance for cooling whose production should imply a high operating flexibility.
  • a further object of the invention is to provide a household appliance for cooling which should be made in a simple, inexpensive and more environment-friendly way.
  • a further object of the invention is to provide a household appliance for cooling which should be made in a more automated and thus reliable manner, with special reference to the above welding operations, eliminating manual welding that are presently carried out for connecting the various circuit devices to one another.
  • a further object of the invention is to combine, where possible, the materials used to make the is various cooling system parts (presently copper, aluminium and steel), replacing them with plastic materials compatible and recyclable without separation, so as to simplify the storage processes of the parts themselves.
  • the invention results from the observation that the slow step phase of the thermal exchange process on the current refrigerating circuits is not heat conduction through the thickness of the exchanger tube, but thermal exchange by natural or forced convection (no frost) between the air and the surface is of the tube itself.
  • the exchangers for household appliances have always been made of metal material (even very expensive like copper), to increase the thermal conductivity of the tube.
  • the invention uses a plastic material, less expensive, better processable, but with lower thermal conductivity, just because the exchange process is not generated by the thermal conductivity of the tube.
  • a preferred but non-exclusive embodiment of a household appliance for cooling shall now be illustrate by way of a non-limiting example according to the present invention and to the annexed figures, wherein:
  • FIG. 1 shows a schematic representation of a refrigeration circuit according to the present invention, and in particular of the type with evaporating tubes;
  • FIG. 2 shows a perspective view of a portion of the refrigeration circuit of a household appliance according to the present invention
  • FIG. 3 shows a partly side and partly dissected representation of a tube usable in a refrigeration circuit according to the present invention and according to a first embodiment
  • FIG. 3 a shows a possible version of section of the tube of FIG. 3 ;
  • FIG. 4 shows a partly side and partly dissected representation of the detail of FIG. 3 consisting of a double layer of plastic material suitable for making the tube wall totally gas-proof according to a different embodiment
  • FIGS. 5 and 6 show two possible sections of a capillary tube used in the circuit according to the finding
  • FIGS. 7 to 10 a show a section of possible embodiments of the heating means used in the tubing according to the finding
  • FIGS. 11-13 show different embodiments of connectors for connecting portions of tubing used in the circuit according to the invention.
  • FIGS. 14 and 15 show the coupling between a capillary tube and tubing according to the present invention
  • FIGS. 14 a , 14 b and 14 c show three possible embodiment versions of a coupling between capillary and corrugated tube for thermal exchange and energy recovery;
  • FIG. 16 shows the coupling between metal tubing and a plastic tubing according to the present invention
  • FIGS. 17-19 show the coupling between two end portions of tubes of plastic material used in the circuit according to the present invention.
  • FIG. 20 shows a possible configuration of coupling between a tubing and the compressor
  • FIGS. 21 a and 21 b show two possible configurations of engagement between tubing and capillary.
  • reference numeral 1 globally indicates a refrigeration apparatus which may be, by way of an example, a refrigerator, a freezer, a deep-freezer, a conditioner or any other appliance mainly for household purpose suitable for cooling a closed ambient, in particular a space 2 , particularly for storing food products or for conditioning a living room.
  • a refrigeration apparatus which may be, by way of an example, a refrigerator, a freezer, a deep-freezer, a conditioner or any other appliance mainly for household purpose suitable for cooling a closed ambient, in particular a space 2 , particularly for storing food products or for conditioning a living room.
  • Apparatus 1 comprises a refrigeration circuit 3 object of the present invention, which is suitable for carrying out a thermo-dynamic refrigerating cycle and is suitable for conveying a cooling fluid along a closed path according to an advance direction indicated with “A” in FIG. 1 .
  • the refrigeration circuit 3 works by a liquid-vapour phase change of the cooling fluid, and comprises a compressor 4 , a condenser 5 , a filter 18 , a lamination device 6 and an evaporator 7 , besides other optional devices suitable for improving the yield of the cooling cycle.
  • the detailed operation of the refrigeration circuit 3 is beyond the contents of the present invention and therefore, it shall not be described hereinafter in detail.
  • Evaporator 7 defines a first heat exchanger which has the function of drawing energy in the form of heat from an inner portion of apparatus 1 , and in particular from space 2 , and transferring it to the cooling fluid circulating through evaporator 7 .
  • Space 2 which in the case of refrigerators is generally intended for storing food or in any case perishable food, is delimitated by walls 8 and is accessible from the exterior of the apparatus, for example by one or more closing ports.
  • evaporator 7 comprises a tubing 9 that extends from a first end 9 a , connectable (optionally through further tubing portions) to the lamination device 6 , to a second end 9 b which usually has the function of heat exchanger with the lamination device 6 , connectable (optionally by further tubing segments as well) to compressor 4 .
  • Tubing 9 is intended for conveying the cooling fluid and allowing transfer of thermal energy (heat) from space 2 towards the cooling fluid circulating in tubing 9 itself.
  • condenser 5 comprises a coil 10 which extends from a first end 10 a , connectable to compressor 4 , to a second end 10 b , connectable to the lamination device 6 and that usually, contains a gas filtering element 18 .
  • Coil 10 is intended for conveying the cooling fluid and allowing transfer of thermal energy from the cooling fluid circulating in coil 10 itself towards an external ambient wherein the apparatus is placed or towards a hot source.
  • coil 10 may consist of a tubing similar to tubing 9 mentioned above but with a smaller diameter, due to the highest operating pressures or, as an alternative, it maybe made by a metal tubing as it commonly happens at present in the refrigerating circuits on the market.
  • the refrigerating fluid belongs to classes HFC (hydrofluorocarbons), HC (hydrocarbons) or mixtures thereof.
  • the cooling fluid used is an aliphatic hydrocarbon such as isobutane, R600a.
  • both tubing 9 and coil 10 are arranged according to respective winding paths (which by way of an example may form 180 degree deflections; however, other equivalent operating geometrical configurations may be taken, as better explained hereinafter), so as to substantially bend on themselves for taking a compact configuration suitable for obtaining an efficient thermal exchange.
  • FIG. 2 shows an example of embodiment of tubing 9 of evaporator 7 , which is applied to a (bottom, or intermediate supporting) surface 11 of a refrigerator and is schematised with a thread-wise pattern to highlight the winding path of tubing 9 itself.
  • tubing 9 is built in a thickness of surface 11 so as to be steadily associated thereto but as an alternative, of course it may be positioned also inside a wall of the apparatus being buried into the same.
  • tubing 9 is made of synthetic and preferably plastic material, so as to simplify the production processes and reduce the overall weight of the circuit.
  • Tubing 9 shall exhibit at least two peculiarities: it shall be not permeable to the cooling fluid that flows therein to prevent contaminations of the environment and loss of refrigerating capability of the circuit, and it shall also ensure humidity/water impermeability to prevent infiltrations (and consequent freezing) of the latter into the refrigeration circuit; moreover, the tubing shall also ensure impermeability to O 2 and N 2 (incondensable gases).
  • Tubing 9 is at least partly, preferably entirely or at least at the curves, defined by a corrugated tube, exhibiting a profile of the type illustrated in FIG. 3 .
  • tubing 9 exhibits an alternation of protrusions 12 and recesses 13 , alternating with one another for defining a substantially undulated outer profile, according to what illustrated in FIGS. 3 and 4 .
  • tubing 9 used for evaporator 7 has a maximum outer diameter “De-max” comprised between 6 mm and 14 mm and preferably within the optimum range 8-11 mm whereas the length of tube 9 for the evaporator will be comprised between 8 and 26 m based on the thermal exchange required and on load losses.
  • the optimum dimensions of the refrigeration circuit, in the condenser section (first heat exchanger 5 ) are as follows: maximum outer diameter De-max of the tube comprised within the range 5-10 mm and, preferably within the range 6-8 mm.
  • the tube length will be comprised within a range between 4-15 m based on the thermal exchange required and on load losses.
  • a fundamental feature of refrigeration circuits besides ensuring the desired thermal exchange, is to constitute a barrier as much as possible impermeable to different agents.
  • the refrigeration circuits work in a range of temperatures from ⁇ 30° to +70° C. and in a range of pressure varying from 0.3 to 12 bar; of course, the impermeability specifications of the above table must be kept within all of these ranges.
  • the lubricating oil of the compressor is partly and uninterruptedly carried along with the coolant it is perfectly soluble with.
  • the oil does not exhibit the features of the coolant, that is, those of evaporating at low temperature, and it is therefore carried by the suction current generated by the compressor along all the refrigeration circuit, or in solution with the coolant or in the form of droplets if (evaporator) the coolant has already evaporated.
  • the velocity of the cooling fluid should in general preferably be higher than 4 m/sec. If not, there is the risk that the compressor may be deprived of the oil that gets trapped in the corrugations of the tube and may burn out.
  • the tube diameter, its length and the shape of the profile corrugation are also involved in the generation of noise inside the tube by the effect of turbulence and of the frequencies of the vortices generated inside the tube itself.
  • Tubing 9 in a possible embodiment, has a step “p”, that is, the distance between two consecutive protrusions 12 , preferably equal to 2 mm.
  • the tubing may have a shape ratio, that is, the ratio between the outer side surface of a portion of tubing and a corresponding longitudinal length of the portion itself, comprised between 20 mm 2 /mm and 60 mm 2 /mm.
  • the corrugated shape of tubing 9 causes an increase in the outer surface of tubing 9 itself relative to a cylindrical tubing having a same length, and in this way the thermal exchange between the cooling fluid circulating inside tubing 9 and the air outside the same is facilitated.
  • the corrugated profile of tubing 9 of plastic material makes the same more flexible compared to a similar cylindrical tubing, allowing bending radiuses and angles that otherwise would cause the squeezing thereof (with reduction of a passage section of the cooling fluid) and thus, adaptable to be arranged according to a plurality of different configurations by simply bending tubing 9 without intervening plastically and irreversibly deforming tubing 9 itself.
  • tubing 9 may exhibit only some corrugated portions, in particular only the portions intended for defining curved portions in the path of tubing 9 itself or those where thermal exchange is to be maximised.
  • tubing 9 in that case intended for defining rectilinear portions, may be smooth or in any case free from surface shaping.
  • the inside diameter of the tubing will be comprised between 4 and 11 mm and preferably between 6-8 mm.
  • Tubing 9 may advantageously be produced by an extrusion process, wherewith a hollow cylindrical extrusion is obtained which may be further modified by in line finishing processes, for obtaining a desired profile of tubing 9 .
  • the extrusion process may be followed by a shaping step that imparts the corrugated shape illustrated in FIG. 3 to the entire hollow cylindrical body or only to a portion thereof.
  • This may be obtained by coupling a counter-shaped matrix to the corrugated profile to be obtained externally to the hollow cylinder body, and generating such pressure inside the body itself as to plastically deform it forcing it to take a shape counter-shaped to the matrix.
  • this step is carried out when the hollow cylindrical body is still at a high temperature, corresponding to a state suitable for a plastic deformation process.
  • the shaping operation described above leads tubing 9 to take a corrugated profile both internally and externally, according to the view of FIG. 3 , and this imparts the flexibility properties mentioned above and of turbulence of the cooling fluid circulating therein.
  • the geometry of the section of the corrugated tube can have also other shapes that aid the improvement of the thermal exchange.
  • evaporator 7 is wound about a metal rack.
  • the tube presently used, metal as well (mainly aluminium) generally has a circular shape and therefore it has a very small contact surface with the metal rack that may be indicated in a single line on all the tube length.
  • tubing 9 is obtained by a multilayer extrusion process (co-extrusion) suitable for improving the mechanical and impermeability properties of tubing 9 .
  • a multilayer extrusion process it is possible to obtain a tubing 9 having two or more layers, each suitably selected based on specific functions to be carried out such as, referring to what already said before, impermeability to the cooling fluid, impermeability to humidity and to incondensable gases, flexibility, thermal conductivity, as well as resistance to the pressure exerted by the cooling fluid.
  • tubing 9 comprises a first layer “S 1 ”, typically outermost, made of a material provided with features adapted for imparting to tubing 9 the necessary resistance to mechanical and thermal strains and impermeable to the is cooling fluids commonly used in cooling apparatus for household purpose (hydrocarbons), and in particular R600a.
  • a material is a polyamide 6; 6-6; 6-12; 11; 12 or one of the respective copolymers, preferably polyamide 6-6
  • tubing 9 comprises a second layer “S 2 ”, usually innermost, made of a material impermeable to water and resistant to hydrolysis (or also N 2 and O 2 ) and characterised by good compatibility with the material of layer S 1 .
  • such material is a copolymer, for example of the type Bynel® by the company DuPont like Bynel® 4206, low density polyethylene modified maleic anhydride or Bynel® 50E662, polypropylene modified maleic anhydride.
  • the second layer “S 2 ” is combined, that is, overlapped, to the first layer “S 1 ” for making a protection of the cooling fluid to any introduction of humidity or water coming from the exterior, improving at the same time the chemical inertia of the tube against the above cooling fluids.
  • the overall thickness S of the tube will be comprised between a minimum and maximum value of 0.4-1.5 mm and of a preferred range between 0.6 and 1.2 mm.
  • Thickness S 1 of the material barrier to humidity and water is comprised between 20% and 40% of the total thickness and is about 30%.
  • thickness S 2 of the material barrier to the cooling fluid and air is about 70% of the total thickness (in general comprised between 60% and 80%).
  • the thickness of the first layer S 1 is comprised between 0.2 mm and 0.4 mm whereas the thickness of the second layer S 2 is preferably comprised between 0.4 mm and 1 mm.
  • condenser 10 Since condenser 10 operates at a higher pressure (2.5-7 bar) than the evaporator (normally 0.5-2.5 bar—the pressure of 2.5 bar common to evaporator and condenser takes place at stationary circuit), it may be useful for the latter to consist of only the material PA6-6 or PA12 without the waterproof layer.
  • the condenser allows the water entered through the evaporator to go out again thus maintaining a balanced situation. This allows maintaining the water molar fraction inside the circuit below certain critical values that the current regulations set to 100 ppm.
  • the above filter 18 is noted, which is arranged between the first exchanger 5 and the lamination device 6 and is suitable for removing any humidity present in the circuit, for example by the use of a gel capable of absorbing it.
  • the lamination unit 6 comprises a capillary tube 19 for reducing the pressure in the passage of the cooling fluid between the first exchanger 5 and the second exchanger 7 . Moreover, in its path it also performs a function of energy recovery exchanging heat between the hot coolant at the liquid state that flows therein and the cold vapour present in the tube at the outlet of evaporator 7 .
  • capillary tube 19 that performs the heat exchange exhibits an outer surface of larger area than that of the tube with circular section; in that case, the section of the capillary tube 19 may exhibit one or more lobes 22 for increasing the thermal exchange.
  • the “lobed” section is illustrated in FIG. 6 and its primary purpose is to increase the outer surface of the tube that exchanges heat with the cooling gas outside.
  • At least a portion of the capillary tube 19 is placed inside a portion of tube 21 in output from evaporator 7 for allowing energy recovery.
  • Tubing 9 ( FIGS. 7 , 8 , 9 , 10 ) then comprises heating means 23 steadily coupled for allowing a selective defrosting of evaporator 7 when required.
  • the defrosting function of the evaporator circuit is carried out automatically by the intervention of electrical resistances external to the circuit.
  • This method of defrosting is not very efficient as it is based on the heat transmission from the electrical resistance of the ice formed on the tubes by radiation.
  • the aim is to obtain the defrosting of the ice by the heating means 23 that are differently coupled in a steady manner to tubing 9 .
  • the heating means 23 comprise, in a first embodiment, at least one metal conductor 24 , preferably thread-like constrained to a layer S of tubing 9 (see FIGS. 7 , 8 , 9 , and 10 ).
  • the metal conductor 24 is constrained to the second layer S 2 inside tubing 9 as in particular it is coextruded with the same and is therefore at least partly buried.
  • FIGS. 7 and 8 show the presence of two electro-conductive wires arranged with prevailing pattern substantially parallel to the development direction of tubing 9 .
  • FIGS. 9 and 10 show the adoption of a thread-like metal conductor 24 wound spiral-wise around the axis of development of tubing 9 .
  • the heating means comprise a layer of conductive material 25 obtained on a surface, preferably external, of tubing 9 (see FIG. 10 a ).
  • conductive layer 25 may be obtained according to different technologies, such as metallization of the tube surface to be made by metallization in high vacuum, by deposition of conductive nanoelements on the tube surface, etc.
  • the coating of the tube with nanoelements may both constitute a further barrier to the inlet of water into the refrigeration circuit, and for the peculiarity of the surface thereof, a factor of increase of the thermal exchange with the air.
  • At least one insulating surface coating 26 will be provided for protecting the heating means 23 from the ambient outside tubing 9 ( FIG. 10 a ).
  • such surface coating 26 may be obtained by deposition of an insulating polymeric film or by other surface coating treatments.
  • the heat required for defrosting the ice is thus transferred by the heating means 23 by direct conduction from the resistance buried in the tube to the ice, thus considerably increasing the efficiency of the defrosting system and reducing energy consumption.
  • tubing 9 may be obtained both by direct extrusion and corrugation with elements of different sizes, and by the assembly of two or more tube portions, preferably corrugated ( FIG. 18 ) but not necessarily so ( FIG. 19 ), having dimensional modularity features.
  • tubing 9 may be obtained from the reciprocal coupling of two, and preferably a plurality of, portions of corrugated tube preferably having same dimensions both in section and in length. This allows obtaining tubing 9 having different lengths starting in any case from portions having a same standard length, and thus suitable for facilitating respective storage processes. In this case in fact it is necessary to have stored only a reduced range of portions, or optionally only one type of tubes, which are then assembled in a sufficient number to make a tubing 9 having a desired length.
  • junctions illustrated may be made with alternative methods, such as vibration welding, laser etc; the purpose of the junctions is to provide a connection of mechanical and/or physical and/or chemical type, which should be impermeable to the cooling gas and to the other gases and humidity mentioned above.
  • the circuit will exhibit a plurality of coupling terminals or connectors 15 for connecting to is each other multiple portions of tube belonging to the refrigeration circuit or connecting the tube itself to the various components.
  • FIG. 11 shows a possible embodiment of the connection between the capillary tube 19 and the corrugated tube 9 belonging to the evaporator.
  • connector 15 comprises a seat 27 suitable for receiving an end 28 of tubing 9 ; the seal between connector 15 and tubing 9 is ensured by a suitable welding.
  • Connector 15 further comprises a through cavity 29 for allowing the passage of the cooling fluid between the connected tubes and the connector itself.
  • the capillary tube 19 entirely crosses the above through cavity bringing directly the cooling fluid at the inlet section of the corrugated tube 9 .
  • the latter comprises a shaped seating portion 31 suitable for being crossed by the end of the capillary tube 19 for defining in cooperation with the latter an irremovable constraint area 30 .
  • the constraint is preferably obtained using suitable glue.
  • the coupling in the left portion between the connector and the tubing portion 21 that contains the capillary may be obtained by welding, using the above seat 27 that receives end 28 of tubing 9 and the welding technology.
  • Connector 15 then comprises an inlet/outlet hole 37 for allowing the passage of the capillary tube 19 from inside tubing 9 to the outer ambient and vice versa (to this end it should be noted that the inlet zone of the capillary tube will be mirror or with different configurations compared to that shown in FIG. 12 where the outlet takes place).
  • connection between the exchanger tube with the return tube from the evaporator exhibits both a glued junction zone (exchanger tube+capillary tube with return tube), and a junction welded by rotation (exchanger tube to the connector).
  • FIG. 13 shows an embodiment version of connection between the exchanger tube with the return tube to the evaporator: in fact, such junction is entirely made by gluing.
  • the shaped seating portion 31 and the tube end define means for first coupling 32 for allowing a first holding into position to the purpose of a subsequent irremovable constraint.
  • first coupling means 32 of FIG. 19 comprise respective expansions 33 and recesses 34 respectively defined in one or in the other of the shaped seating portions 31 and of the ends of the tube to ensure a first engagement by interference that maintains the reciprocal position during the subsequent permanent junction steps.
  • expansions 33 and recesses 34 are placed relative to each other so as to ensure the keeping of the position during the irremovable constraint steps (by glue, welding or the like).
  • first coupling means 32 may be used for connecting subsequent tubing portions directly to one another, as clearly shown in FIG. 19 .
  • FIG. 15 shown an embodiment version wherein the inlet/outlet hole 37 , instead of being at the normal corrugations of the tubing, is defined in a pre-shaped zone 38 suitable for defining a flat inlet/outlet area of the capillary tube that is substantially parallel to the axis of the tube itself.
  • FIG. 16 shows how to connect metal tubes belonging to the circuit (for example the inlets and the outlets from the compressor identified with reference 35 ) to tube 9 according to the invention.
  • an end of tubing 9 is overlapped to a corresponding end of a metal tube 35 and there is an over-pressing element 36 for irremovably constraining said ends.
  • evaporator 7 comprises a flexible tubing 9 made of plastic material
  • condenser 5 comprises a conventional metal coil 10 which is welded to the remaining part of the refrigeration circuit 3 .
  • an apparatus 1 exhibiting both coil 10 of condenser 5 and tubing 9 of evaporator 10 of synthetic material, preferably one or more plastic materials of the type described above.
  • the present invention attains the proposed objects, overcoming the disadvantages mentioned in the prior art.
  • connectors that in any case are elements of discontinuity in the circuit and that have a certain cost, may be avoided using corrugators of higher length and provided with shaping elements shaped to obtain different sections in the same continuously extruded corrugated tube; the above sections with special shape, for example required for coupling to the copper tube ( 35 ), may be obtained by continuous extrusion and corrugation with shaped elements.
  • the exchanger tube 17 may be extruded continuously with tube 9 of evaporator 7 , inserting in the corrugator, if required, shaped elements that allow obtaining section 38 for inserting capillary 19 and the final portion 36 for over-pressing. In this way it is possible to prevent some coupling joints, making the refrigeration circuit safer and less expensive.
  • the corrugated shape, at least in portions, of the tubing allows an increase of the thermal exchange surface since the corrugated shape of the tubing exhibits a greater outer surface than a corresponding smooth or in any case perfectly cylindrical tubing. Moreover, the corrugated shape also inside the tubing itself allows generating whirling motions in the cooling fluid that positively affect the thermal exchange made by the fluid itself.
  • the lamination device 6 and art of the exchanger tube constitute a tubular exchanger having an inner tube a calibrated polyamide tube, wherein the liquid to be cooled flows, and an outer tube, optionally coextruded with the inner one ( FIGS. 14 a , 14 b ) or rolled up or coextruded/rolled up ( 14 c ) externally or internally to tube 17 , wherein the vapour to be heated to be then compressed by the compressor without droplets flows.
  • the device described above may be entirely made of plastic material and in the desired shapes, unlike what occurs presently using metals which, for obvious reasons, limit shapes and length thereof.
  • tube 17 may also be obtained as simple extension of tube 9 of evaporator 7 thus eliminating a junction.
  • Both such device and the various components of the refrigeration circuit are then suitable for being made by coextrusion of plastic material with inserted one or more thin metal wires, usable as resistances for the quick defrosting of the evaporator or any other part of the circuit, or for overheating the vapour to be sent to the compressor.
  • the tube or portions thereof may be made by coextrusion of one or more layers of plastic material covered by a special lake (further outer layer) containing conductive nanoelements; such lake will be applicable by spray during the extrusion or afterwards on the already assembled work or as an alternative even by immersion in a special bath and will have the characteristic of generating heat when crossed by an electrical current, so as to carry out the function of defrosting or heating device of specific zones of the refrigeration circuit.
  • a special lake further outer layer
  • conductive nanoelements such lake will be applicable by spray during the extrusion or afterwards on the already assembled work or as an alternative even by immersion in a special bath and will have the characteristic of generating heat when crossed by an electrical current, so as to carry out the function of defrosting or heating device of specific zones of the refrigeration circuit.
  • Condensers 10 may be made similarly to what described for evaporators 9 , making the plastic material tube shapes and sizes in the most suitable possible manner for the operating requirements of the refrigerating appliances.
  • Condensers 10 operating upstream of the compressor must higher pressures than those of evaporators 7 . For this reason, they should meet more restrictive rules, in particular they should withstand a pressure of 36 bar.
  • the thickness of corrugated tubes must be increased to no less than 0.7 mm (preferably 0.8-1.4 mm) and it is thus important to increase the thermal exchange surfaces making suitable geometries. All these components of the circuit may be coupled to each other by the above connectors, allowing assembly saving (they are presently welded to one another) and assembly safety.
  • connections between the components of the refrigeration circuit may be obtained by rotation welding operations or gluing by the use of quick connections with seals (o-rings or alternative ones) as sealing element.
  • the described invention thus eliminates the complex and expensive processes for making the metal tube and bending the same for obtaining the traditional metal coil of the evaporator, and the range of products on stock is reduced since it is necessary to store only the tubing that has not received the final winding and bent configuration yet. Also the need of storing the tubing may be easily eliminated having an extrusion and corrugation line for the plastic tube the cost whereof is at least 20 times less than a production line for metal tubes and for the operation whereof it is necessary to have a covered surface much smaller than that required for a production line of the metal tube.
  • the condenser tube 5 may be coextruded to tube 10 b and having special elements in the corrugator, the seat of filter 18 may be obtained in the same way without the use of connectors with the economic and safety advantages described above ( FIGS. 21 a and 21 b ).

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Geometry (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
US12/669,004 2007-07-16 2008-07-08 Refrigeration circuit Abandoned US20100192623A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IT001419A ITMI20071419A1 (it) 2007-07-16 2007-07-16 Circuito di raffreddamento
ITMI2007A001419 2007-07-16
PCT/IB2008/001795 WO2009010839A2 (fr) 2007-07-16 2008-07-08 Circuit de réfrigération

Publications (1)

Publication Number Publication Date
US20100192623A1 true US20100192623A1 (en) 2010-08-05

Family

ID=40130806

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/669,004 Abandoned US20100192623A1 (en) 2007-07-16 2008-07-08 Refrigeration circuit

Country Status (10)

Country Link
US (1) US20100192623A1 (fr)
EP (1) EP2171374A2 (fr)
CN (1) CN101821563B (fr)
AR (1) AR067532A1 (fr)
BR (1) BRPI0813510A2 (fr)
CO (1) CO6300810A2 (fr)
IN (1) IN2010KN00163A (fr)
IT (1) ITMI20071419A1 (fr)
RU (1) RU2490566C2 (fr)
WO (1) WO2009010839A2 (fr)

Cited By (5)

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Publication number Priority date Publication date Assignee Title
US20180066873A1 (en) * 2015-05-27 2018-03-08 Mitsubishi Electric Corporation Compressor and refrigeration cycle apparatus
US10982870B2 (en) 2018-08-31 2021-04-20 Jonhson Controls Technology Company Working fluid distribution systems
US20210302079A1 (en) * 2020-03-25 2021-09-30 Carrier Corporation Fluid conduit connection of an hvac system
US11674620B2 (en) 2017-03-06 2023-06-13 Xinchang County Sitong Electrical Co., Ltd Vibration absorption tubing and manufacturing method thereof
US20240150955A1 (en) * 2019-08-14 2024-05-09 Lg Electronics Inc. Heat exchanger and manufacturing method of home appliance including the heat exchanger

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CN104952533A (zh) * 2015-06-11 2015-09-30 深圳市骏鼎达科技有限公司 复合型套管、复合型波纹套管及其制造方法
CN108194676A (zh) * 2017-12-29 2018-06-22 浙江省平湖市北辰实业有限公司 一种减震效果好的四通阀
CN216114849U (zh) * 2021-07-26 2022-03-22 合肥海尔电冰箱有限公司 管间固定件、蒸发器及冰箱
CN114526629A (zh) * 2022-02-24 2022-05-24 东莞市瑞为电器配件有限公司 一种热交换装置及其制造方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180066873A1 (en) * 2015-05-27 2018-03-08 Mitsubishi Electric Corporation Compressor and refrigeration cycle apparatus
US11313593B2 (en) * 2015-05-27 2022-04-26 Mitsubishi Electric Corporation Compressor and refrigeration cycle apparatus
US11674620B2 (en) 2017-03-06 2023-06-13 Xinchang County Sitong Electrical Co., Ltd Vibration absorption tubing and manufacturing method thereof
US10982870B2 (en) 2018-08-31 2021-04-20 Jonhson Controls Technology Company Working fluid distribution systems
US20240150955A1 (en) * 2019-08-14 2024-05-09 Lg Electronics Inc. Heat exchanger and manufacturing method of home appliance including the heat exchanger
US20210302079A1 (en) * 2020-03-25 2021-09-30 Carrier Corporation Fluid conduit connection of an hvac system

Also Published As

Publication number Publication date
RU2010100987A (ru) 2011-09-20
CO6300810A2 (es) 2011-07-21
BRPI0813510A2 (pt) 2018-12-26
EP2171374A2 (fr) 2010-04-07
IN2010KN00163A (fr) 2015-08-28
CN101821563A (zh) 2010-09-01
ITMI20071419A1 (it) 2009-01-17
CN101821563B (zh) 2014-03-12
RU2490566C2 (ru) 2013-08-20
WO2009010839A3 (fr) 2009-05-07
AR067532A1 (es) 2009-10-14
WO2009010839A2 (fr) 2009-01-22

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