WO2000066959A1 - Resistance element for defrosting evaporators in refrigeration units - Google Patents

Resistance element for defrosting evaporators in refrigeration units Download PDF

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Publication number
WO2000066959A1
WO2000066959A1 PCT/EP1999/002867 EP9902867W WO0066959A1 WO 2000066959 A1 WO2000066959 A1 WO 2000066959A1 EP 9902867 W EP9902867 W EP 9902867W WO 0066959 A1 WO0066959 A1 WO 0066959A1
Authority
WO
WIPO (PCT)
Prior art keywords
resistance element
temperature
sheath
refrigeration units
surrounded
Prior art date
Application number
PCT/EP1999/002867
Other languages
French (fr)
Inventor
Gianangelo Perozzo
Ivano Dal Col
Original Assignee
I.R.C.A. S.P.A. - Industria Resistenze Corazzate E Affini
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 I.R.C.A. S.P.A. - Industria Resistenze Corazzate E Affini filed Critical I.R.C.A. S.P.A. - Industria Resistenze Corazzate E Affini
Priority to AU39292/99A priority Critical patent/AU3929299A/en
Priority to PCT/EP1999/002867 priority patent/WO2000066959A1/en
Publication of WO2000066959A1 publication Critical patent/WO2000066959A1/en

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/40—Heating elements having the shape of rods or tubes
    • H05B3/42—Heating elements having the shape of rods or tubes non-flexible
    • H05B3/48—Heating elements having the shape of rods or tubes non-flexible heating conductor embedded in insulating material
    • 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
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/06—Removing frost
    • F25D21/08—Removing frost by electric heating
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/02—Heaters using heating elements having a positive temperature coefficient

Definitions

  • This invention relates to a resistance element for defrosting evaporators in refrigeration units. Resistance elements used for this purpose are known.
  • the resistance elements are currently mounted on the finned pack after which, but not necessarily, a thermostat and/or a safety temperature fuse able to sense ambient temperature are mounted.
  • the purpose of the thermostat is to prevent current passage on attaining a predetermined temperature, the purpose of the temperature fuse being to intervene if the thermostat does not operate, in which case overheating of the resistance element could occur with consequent damage.
  • a further object of the invention is to provide a combined resistance element and temperature controls which is of small overall size.
  • a resistance element for evaporators in refrigeration units comprising a resistive wire surrounded by a layer of dielectric material and housed in a sheath of heat-conducting material, to the ends of the sheath there being applied at least one temperature limiting element and one temperature regulating element, characterised in that said elements have their sensitive part in contact with the sheath and are surrounded by a block of heat-insulating material.
  • Figure 1 is a schematic view of the resistance element applied to an evaporator
  • Figure 2 is a perspective view of the resistance element
  • Figure 3 is a longitudinal section through the part by which the thermostat is fixed to the resistance element.
  • the resistance element of the invention is indicated overall by 2 and consists of a resistive wire 4 covered with a glass fibre core which itself is covered with a layer of silicone, all housed in a tubular aluminium sheath 6.
  • Said resistance element 2 which extends with such a configuration as to enable it to adapt to the finned pack 8 of the evaporator, comprises at its ends a thermostat 10 and a temperature fuse 12.
  • the thermostat 10 which is of the bimetallic strip type, rests directly on the tubular sheath 6, and is enclosed by a resin block 14 obtained by injection in a mould formed from two half-moulds provided with the corresponding impressions.
  • the thermostat has a maximum operating temperature less than the activation temperature of the fuse.
  • the device operates in the following manner.
  • the timer activates the resistance element which however can only operate if the thermostat positioned inside the refrigeration unit senses a temperature less than the limiting temperature.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuses (AREA)

Abstract

A resistance element for evaporators in refrigeration units comprising a resistive wire (4) surrounded by a layer of dielectric material and housed in a sheath (6) of heat-conducting material, to the ends of the sheath there being applied at least one temperatrue limiting element (12) and one temperature regulating element (10), characterised in that said elements have their sensitive part in contact with the sheath and are surrounded by a block of heat-insulating material.

Description

RESISTANCE ELEMENT FOR DEFROSTING EVAPORATORS IN REFRIGERATION UNITS
This invention relates to a resistance element for defrosting evaporators in refrigeration units. Resistance elements used for this purpose are known.
The resistance elements are currently mounted on the finned pack after which, but not necessarily, a thermostat and/or a safety temperature fuse able to sense ambient temperature are mounted.
The purpose of the thermostat is to prevent current passage on attaining a predetermined temperature, the purpose of the temperature fuse being to intervene if the thermostat does not operate, in which case overheating of the resistance element could occur with consequent damage.
These known resistance elements have however certain drawbacks, and in particular: - the appliance manufacturer has to assemble the thermostat and the temperature fuse, with consequent time loss,
- temperature control is not reliable in that as the thermostat senses ambient temperature, which is less than the temperature of the resistance element, it may not intervene when the temperature of the resistance element reaches the limiting value, but later. Because of this, plastic parts and components cannot be reliably used in contact with the heating element, because of safety problems related to high temperature.
An object of the invention is to eliminate these drawbacks by providing a resistance element for evaporators in refrigeration units which reliably intervenes when the limiting temperature is exceeded. Another object of the invention is to provide a resistance element which improves the effectiveness of the defrosting process by being able to operate at the correct temperature.
A further object of the invention is to provide a combined resistance element and temperature controls which is of small overall size.
These and further objects are attained according to the invention by a resistance element for evaporators in refrigeration units comprising a resistive wire surrounded by a layer of dielectric material and housed in a sheath of heat-conducting material, to the ends of the sheath there being applied at least one temperature limiting element and one temperature regulating element, characterised in that said elements have their sensitive part in contact with the sheath and are surrounded by a block of heat-insulating material.
The invention is described in detail hereinafter with reference to the accompanying drawing, on which:
Figure 1 is a schematic view of the resistance element applied to an evaporator; Figure 2 is a perspective view of the resistance element; Figure 3 is a longitudinal section through the part by which the thermostat is fixed to the resistance element.
As can be seen from the figures the resistance element of the invention is indicated overall by 2 and consists of a resistive wire 4 covered with a glass fibre core which itself is covered with a layer of silicone, all housed in a tubular aluminium sheath 6. Said resistance element 2, which extends with such a configuration as to enable it to adapt to the finned pack 8 of the evaporator, comprises at its ends a thermostat 10 and a temperature fuse 12.
The thermostat 10, which is of the bimetallic strip type, rests directly on the tubular sheath 6, and is enclosed by a resin block 14 obtained by injection in a mould formed from two half-moulds provided with the corresponding impressions.
The thermostat has a maximum operating temperature less than the activation temperature of the fuse. The device operates in the following manner.
At normally predetermined intervals the timer activates the resistance element which however can only operate if the thermostat positioned inside the refrigeration unit senses a temperature less than the limiting temperature.
From the aforegoing it is apparent that the resistance element of the invention provides numerous advantages, and in particular:
- a smaller overall size than known assembled devices available commercially, - improved efficiency of the defrosting process as the temperature sensor measures the real temperature of the resistance element sheath, it being in contact with it and thermally insulated towards the outside, hence preventing the resistance element and those evaporator regions in contact with it from reaching too high a temperature and limiting defrosting to the time necessary,
- it ensures correct current passage interruption on exceeding the set temperature, hence if this value is of a suitable level it enables components with a lower temperature limit to be used. The description refers to an aluminium resistance element, however the invention can be applied to armoured resistance elements of steel construction in which the resistive wire is surrounded by magnesium oxide.

Claims

C L A I M S
1. A resistance element for evaporators in refrigeration units comprising a resistive wire (4) surrounded by a layer of dielectric material and housed in a sheath (6) of heat-conducting material, to the ends of the sheath there being applied at least one temperature limiting element (12) and one temperature regulating element (10), characterised in that said elements have their sensitive part in contact with the sheath and are surrounded by a block of heat-insulating material.
2. A resistance element as claimed in claim 1 , characterised in that both elements consist of bimetallic thermostats with different operating temperatures.
3. A resistance element as claimed in claim 1 , characterised in that the regulating element consists of a temperature sensor and the limiting element consists of a temperature fuse.
PCT/EP1999/002867 1999-04-28 1999-04-28 Resistance element for defrosting evaporators in refrigeration units WO2000066959A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU39292/99A AU3929299A (en) 1999-04-28 1999-04-28 Resistance element for defrosting evaporators in refrigeration units
PCT/EP1999/002867 WO2000066959A1 (en) 1999-04-28 1999-04-28 Resistance element for defrosting evaporators in refrigeration units

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP1999/002867 WO2000066959A1 (en) 1999-04-28 1999-04-28 Resistance element for defrosting evaporators in refrigeration units

Publications (1)

Publication Number Publication Date
WO2000066959A1 true WO2000066959A1 (en) 2000-11-09

Family

ID=8167277

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1999/002867 WO2000066959A1 (en) 1999-04-28 1999-04-28 Resistance element for defrosting evaporators in refrigeration units

Country Status (2)

Country Link
AU (1) AU3929299A (en)
WO (1) WO2000066959A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009134052A3 (en) * 2008-04-28 2009-12-23 주식회사 에이엠오 Defrosting heater using strip type plane heating element, manufacturing method thereof and defrosting device using the same
WO2011026207A3 (en) * 2009-09-01 2011-07-21 Whirlpool S.A. Defrosting device for evaporators
WO2019145780A1 (en) * 2018-01-25 2019-08-01 Zoppas Industries De Mexico S.A., De C.V. Sheathed fiberglass heater wire
IT201900012903A1 (en) * 2019-07-25 2021-01-25 Irca Spa ELECTRIC HEATER

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1094486A (en) * 1953-11-23 1955-05-20 Improvements to refrigeration devices
US2758150A (en) * 1952-07-22 1956-08-07 Gen Electric Electrical connector for refrigerator defrosting means
US3099914A (en) * 1961-12-29 1963-08-06 Gen Electric Refrigerating apparatus
GB940499A (en) * 1959-09-18 1963-10-30 Merlin Mouldings Ltd Improvements in or relating to electric heating elements
US4112410A (en) * 1976-11-26 1978-09-05 Watlow Electric Manufacturing Company Heater and method of making same
US4358667A (en) * 1977-12-16 1982-11-09 International Telephone And Telegraph Corporation Cartridge-type electric immersion heating element having an integrally contained thermostat
US4432211A (en) * 1980-11-17 1984-02-21 Hitachi, Ltd. Defrosting apparatus
EP0204850A1 (en) * 1985-06-05 1986-12-17 Elpag Ag Chur Tubular heating element
EP0456216A2 (en) * 1990-05-08 1991-11-13 Elpag Ag Chur Tubular heating element with fuse
DE9416355U1 (en) * 1994-05-18 1994-12-08 Whirlpool Europe B.V., Amsterdam Device for controlling the defrosting of the evaporator
EP0660644A2 (en) * 1993-12-23 1995-06-28 Elpag Ag Chur Tubular heating element with overload protection and temperature sensor
FR2754128A1 (en) * 1996-09-27 1998-04-03 Vulcanic Tubular heating element for electric radiator

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2758150A (en) * 1952-07-22 1956-08-07 Gen Electric Electrical connector for refrigerator defrosting means
FR1094486A (en) * 1953-11-23 1955-05-20 Improvements to refrigeration devices
GB940499A (en) * 1959-09-18 1963-10-30 Merlin Mouldings Ltd Improvements in or relating to electric heating elements
US3099914A (en) * 1961-12-29 1963-08-06 Gen Electric Refrigerating apparatus
US4112410A (en) * 1976-11-26 1978-09-05 Watlow Electric Manufacturing Company Heater and method of making same
US4358667A (en) * 1977-12-16 1982-11-09 International Telephone And Telegraph Corporation Cartridge-type electric immersion heating element having an integrally contained thermostat
US4432211A (en) * 1980-11-17 1984-02-21 Hitachi, Ltd. Defrosting apparatus
EP0204850A1 (en) * 1985-06-05 1986-12-17 Elpag Ag Chur Tubular heating element
EP0456216A2 (en) * 1990-05-08 1991-11-13 Elpag Ag Chur Tubular heating element with fuse
EP0660644A2 (en) * 1993-12-23 1995-06-28 Elpag Ag Chur Tubular heating element with overload protection and temperature sensor
DE9416355U1 (en) * 1994-05-18 1994-12-08 Whirlpool Europe B.V., Amsterdam Device for controlling the defrosting of the evaporator
FR2754128A1 (en) * 1996-09-27 1998-04-03 Vulcanic Tubular heating element for electric radiator

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009134052A3 (en) * 2008-04-28 2009-12-23 주식회사 에이엠오 Defrosting heater using strip type plane heating element, manufacturing method thereof and defrosting device using the same
US8405009B2 (en) 2008-04-28 2013-03-26 Amogreentech Co., Ltd. Defrost heater using strip type surface heat emission element and fabricating method thereof and defrost apparatus using the same
WO2011026207A3 (en) * 2009-09-01 2011-07-21 Whirlpool S.A. Defrosting device for evaporators
WO2019145780A1 (en) * 2018-01-25 2019-08-01 Zoppas Industries De Mexico S.A., De C.V. Sheathed fiberglass heater wire
US11920853B2 (en) 2018-01-25 2024-03-05 Zoppas Industries De Mexico S.A., De C.V. Sheathed fiberglass heater wire
IT201900012903A1 (en) * 2019-07-25 2021-01-25 Irca Spa ELECTRIC HEATER
WO2021014432A1 (en) * 2019-07-25 2021-01-28 I.R.C.A. S.P.A. Industria Resistenze Corazzate E Affini Electric heater
CN114731741A (en) * 2019-07-25 2022-07-08 I.R.C.A.（共同）股份公司工业铠装及类似电阻 Electric heater

Also Published As

Publication number Publication date
AU3929299A (en) 2000-11-17

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