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
  • F25B49/00—Arrangement or mounting of control or safety devices
  • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
  • F25B49/025—Motor control arrangements
• • 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
  • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
  • F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
• • 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
  • F25B2600/00—Control issues
  • F25B2600/02—Compressor control
  • F25B2600/025—Compressor control by controlling speed
  • F25B2600/0251—Compressor control by controlling speed with on-off operation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Definitions

• the piesent invention lefeis to improvements in the 1 efngeratmg cncuits of household and sirmlai l ef ⁇ geration apparatuses (refrigerators, freezeis and the bke) of the type comprising a hermetically sealed compressoi , which is driven by an electric brushless, electronically controlled motoi , and electromagnetic valve means that aie adapted to cut off the flow of the refrigerant medium upstream of the expansion device
• a well-known diawback of I efngeratmg circuits of the above mentioned kind is due to the fact that, dunng the pauses determined by the control thermostat of the appliance in the opei ation of the compiessor, part of the le ⁇ igerant medium migrates fiom the condenser (le.
• lefngei ant medium in the gaseous state is already piesent at the inlet of said capillaiy tube
• the refrigeration effect is extiemely reduced foi a certain time aftei compressor restarting.
• the motoi driving the compiessoi uses electric energy for pioducmg a 1 educed amount of lefngeiation
• Pressostatic, le piessure-sensitive valve means aie for instance known which when added directly to a refrigerating circuit, advantageously cut off the flow of refrigerant medium in the capillary tube during the thermostatically determined pauses of the compiessoi , and which are then capable of automatically restoring said flow each time that the same compiessor is restarted (see document US-A-4 267 702) Howevei , these piessostatic means due to their being of the mechanical type and requiring construction modifications, particularly in the form of welded oi mechanical joints that in all cases constitute as many potential refrigerant leakage souices, consideiably contribute to a reduction m the overall lebabibty of the l eft lgei atmg circuit
• valve means pioducing similai effects as the above cited ones are also known, which are operationally bnked with temperature sensors (see document US-A-4 286 438)
• These othei means do not lequire any modification to the lef ⁇ geiating circuits, however, the unavoidable thermal inertia and the practical difficulty in identifying a rebable position m which to locate the sensois, usually on the coils of the condensei of the lefngeiating circuit, le on the outside of the le ⁇ igeration appbance, generally pi event the opening and closing of said valve means fiom being co ⁇ ectly and lebably timed with the start and stop cycbng of the motoi dnvmg the compressoi
• Figure 1 is a block diagiam of a I efngeratmg cncuit accoiding to the present invention
• Figui e 2 is diagi ammatical view of the evolution patterns of the pressui es of the lefngeiant medium at the suction and debvery sides of the compiessor du ng a certain time of opeiation thereof
• a refngeiating circuit foi a household or sirmla lefiigeiation appaiatus compnses a hermetically sealed compressor 1 , whose shell also encloses the d vmg motoi , a condensei 2, a dehydrator-filtei 3, a capillaiy tube 4 foi the substantially lsoenthalpic expansion of the refngerant medium, and an evapoi atoi 5
• the compressoi 1 is of the type descnbed in the afoie mentioned patent EP-A-0 490 089 to the same Appbcant, le of the type dnven by a biushless motoi associated to a frequency contiol anangement 7
• Said fiequency contiol arrangement is such as to ensuie that, undei any load condition whatsoevei , the motoi is capable of operating at an automatically conti oiled lotational speed that optimizes the perfoimance of the compiessoi , said lotational speed being in all cases slowei than the lated one, detei mined by the fiequency of the powei supply system, of an equivalent induction motor of the ti aditional type
• the connection between the compressoi 1 and said frequency control arrangement 7 is established any appropriate manner, in particular through conventional electric wires 6.
• a bistable, unidirectional valve 8 of any per se known type, eg. the one described in the document IT-A-1 203 572.
• Any other type of valve may however be used, provided that it is of the type that absorbs power only in the switching transients from the closed position to the open one, and vice-versa, in order to avoid using energy unnecessarily.
• the operation of the bistable valve 8 is interlinked with the same frequency control arrangement 7 which also the operation of the motor driving the compressor 1 is actually interlinked with. Even in the case of the connection between the valve 8 and said frequency control arrangement 7, this can be estabbshed in any appropriate manner, in particular through conventional electric wires 9.
• the "downstieam” pressuie uses fiom ⁇ n initial lowei value p' e to an upper value p" ⁇ and stab ⁇ zes at such uppei value thioughout most of the period of operation 1A which teiminates at the instant Tl , when the compressor is switched off and stops operating (due to the contiol thermostat of the apparatus tripping in the well-known mannei)
• the "upstieam” pressuie deci eases rapidly from an uppei initial value p', to a sbghtly lower value p", and then remains substantially unaltered until the final instant Tl Starting from said instant Tl , and throughout the entne period of pause IB of the compiessoi (terminating with the same compressoi lestarting at the instant T2), the "downstream” pressuie decreases fiom the initial

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Control Of Positive-Displacement Pumps (AREA)
• Air Conditioning Control Device (AREA)
• Telephonic Communication Services (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=11395170

Family Applications (1)

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• 1996
  • 1996-07-16 IT IT96PN000044A patent/IT1289387B1/it active IP Right Grant
• 1997
  • 1997-06-24 WO PCT/EP1997/003310 patent/WO1998002697A1/en not_active Application Discontinuation
  • 1997-06-24 BR BR9710245A patent/BR9710245A/pt not_active Application Discontinuation
  • 1997-06-24 EP EP97930392A patent/EP0912866A1/en not_active Withdrawn
  • 1997-06-24 JP JP10505543A patent/JP2000514544A/ja active Pending

Non-Patent Citations (1)

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