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EP-4057774-B1 - HEATER BUNDLES HAVING VARIABLE POWER OUTPUT WITHIN ZONES

EP4057774B1EP 4057774 B1EP4057774 B1EP 4057774B1EP-4057774-B1

Inventors

  • EVERLY, MARK
  • BOEHMER, Scott

Dates

Publication Date
20260506
Application Date
20220310

Claims (15)

  1. A heater system (10) comprising: a heater bundle (12) comprising: a plurality of heater assemblies (18), at least one of the heater assemblies (18) comprising a plurality of heater units (52), at least one heater unit having an independently controlled heating zone (62); a plurality of power conductors electrically connected to the plurality of heater units; means for determining temperature; and a power supply device including a controller configured to modulate power to the independently controlled heating zone through the power conductors based on the determined temperature to provide a desired power output along a length of the at least one heater assembly, characterized in that the at least one heater assembly comprises a physical construction configured to deliver a variable power output per unit length along a length of the at least one heater assembly.
  2. The heater system (10) according to Claim 1, wherein the physical construction comprises a resistive heating element (120) within at least one heater unit (52) having a variable pitch (P 1 , P 2 , P 3 ).
  3. The heater system (10) according to Claim 2, wherein the variable pitch is continuously variable along a length of the resistive heating element (120).
  4. The heater system (10) according to Claim 1, wherein the physical construction comprises a resistive heating element (120) within at least one heater unit (52) having a variable cross-sectional area.
  5. The heater system (10) according to Claim 1, wherein the physical construction comprises a resistive heating element (120) within at least one heater unit (52) having a variable cross-sectional area and a variable pitch.
  6. The heater system (10) according to Claim 1, wherein the physical construction comprises a plurality of parallel circuits within at least one heater unit (52).
  7. The heater system (10) according to Claim 1, wherein the physical construction is provided in more than one of the plurality of heater units (52).
  8. The heater system (10) according to Claim 1 wherein the physical construction comprises a composite heating element having a higher electrical resistivity proximate an adjacent heater unit or an end portion of the at least one heater assembly and a lower electrical resistivity proximate another opposed adjacent heater unit (52).
  9. The heater system (10) according to Claim 1, wherein the physical construction is provided in more than one of the heater assemblies (18).
  10. The heater system (10) according to Claim 1, wherein at least one heater assembly (18) from among the plurality of the heater assemblies is a cartridge heater (30).
  11. The heater system (10) according to Claim 1, wherein the physical construction comprises at least one heater unit (18) having a cross-sectional area that is different from adjacent heater units (18).
  12. The heater system (10) according to Claim 1, wherein the heater units (18) include a plurality of resistive heating elements (120), wherein at least one of the resistive heating elements functions as a sensor.
  13. The heater system (10) according to Claim 1, wherein the physical construction comprises a composite heating element having a variable electrical resistivity.
  14. The heater system (10) according to Claim 13, wherein the variable electrical resistivity comprises a higher electrical resistivity proximate an adjacent heater unit or an end portion of the at least one heater assembly and a lower electrical resistivity proximate an opposed adjacent heater unit.
  15. An apparatus (70) for heating fluid comprising: a sealed housing (72) defining an internal chamber and having a fluid inlet (76) and a fluid outlet (78); and the heater system (10) according to Claim 1, the heater bundle (12) being disposed within the internal chamber of the housing, wherein the heater bundle (12) is adapted to provide a responsive heat distribution to a fluid within the housing (72).

Description

FIELD The present disclosure relates to electric heaters, and more particularly to heaters for heating a fluid flow such as heat exchangers. BACKGROUND The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. A fluid heater may be in the form of a cartridge heater, which has a rod configuration to heat fluid that flows along or past an exterior surface of the cartridge heater. The cartridge heater may be disposed inside a heat exchanger for heating the fluid flowing through the heat exchanger. If the cartridge heater is not properly sealed, moisture and fluid may enter the cartridge heater to contaminate the insulation material that electrically insulates a resistive heating element from the metal sheath of the cartridge heater, resulting in dielectric breakdown and consequently heater failure. The moisture can also cause short circuiting between power conductors and the outer metal sheath. The failure of the cartridge heater may cause costly downtime of the apparatus that uses the cartridge heater. Documents US 2017/254564 A1, US 2017/254565 A1, WO 2018/009768 A1, US 2008/083741 A1 and US 2016/295641 A1 disclose heating system to heat fluid according to the prior art. SUMMARY The present disclosure provides a heater system comprising a heater bundle, the heater bundle comprising a plurality of heater assemblies, at least one of the heater assemblies comprising a plurality of heater units, at least one heater unit having an independently controlled heating zone, and the at least one heater assembly comprising a physical construction configured to deliver a variable power output per unit length along a length of the at least one heater assembly. A plurality of power conductors are electrically connected to the plurality of heater units, and the heater system further comprises a means for determining temperature. A power supply device includes a controller configured to modulate power to the independently controlled heating zone through the power conductors based on the determined temperature to provide a desired power output along a length of the at least one heater assembly. In variations of this heater system, which may be implemented individually or in any combination: the physical construction comprises a resistive heating element within at least one heater unit having a variable pitch; the variable pitch is continuously variable along a length of the resistive heating element; the physical construction comprises a resistive heating element within at least one heater unit having a variable cross-sectional area; the physical construction comprises a resistive heating element within at least one heater unit having a variable cross-sectional area and a variable pitch; the physical construction comprises a plurality of parallel circuits within at least one heater unit; the physical construction is provided in more than one of the plurality of heater units; the physical construction comprises a composite heating element having a higher electrical resistivity proximate an adjacent heater unit or an end portion of the at least one heater assembly and a lower electrical resistivity proximate another opposed adjacent heater unit; the physical construction is provided in more than one of the heater assemblies; at least one heater assembly from among the plurality of the heater assemblies is a cartridge heater; the physical construction comprises at least one heater unit having a cross-sectional area that is different from adjacent heater units; the heater units include a plurality of resistive heating elements, wherein at least one of the resistive heating elements functions as a sensor; the physical construction comprises a composite heating element having a variable electrical resistivity; the variable electrical resistivity comprises a higher electrical resistivity proximate an adjacent heater unit or an end portion of the at least one heater assembly and a lower electrical resistivity proximate an opposed adjacent heater unit. In another form, an apparatus for heating fluid comprises the aforementioned heater system along with a sealed housing defining an internal chamber and having a fluid inlet and a fluid outlet, the heater bundle being disposed within the internal chamber of the housing. The heater bundle is adapted to provide a responsive heat distribution to a fluid within the housing. In still another form, a heater system includes a heater bundle comprising a plurality of heater assemblies, at least one of the heater assemblies comprising a plurality of heater units, at least one heater unit having an independently controlled heating zone, and the at least one heater assembly comprising a physical construction configured to deliver a variable power output per unit length along a length of the at least one heater assembly. A plurality of power conductors are electrically connected to the heater units, and a means for determi