Bundle Rod Heater

Marathon make Bundle rod heater consists of circular ceramic disc that holds the heating elements, in combination with the radiant tubes which delivers high power, avoid refractory corrosion and avoid the gas impurity in process materials. This design is suitable for long life and maintenance free operation. The element can be provided in ferritic alloys up to 1250° C and Ni Cr alloy up to 1100°C materials.

Construction

1. Direct heating element wire

2. Ceramic Disc : for hold the heating element & insulation

3. Fiber Disc : for holds the terminal rod and prevent heat loss

4. Center rod : for alignment & take weight of heater bundle

 

Advantages

  • Reduces carbon dioxide emissions by eliminating flue gases and controllable aural various heat treatment furnace, to avoid the contact of burning outcome or to avoid the corrosion of furnace gas to heating element
  • The control of temperature, assemble and maintenance are very convenient and can be easy to seal.
  • Horizontal or vertical mounting
  • Minimized environmental impact
  • Longer working life and better technical properties
  • Higher surface load & resistivity
  • Free from oxide debris
  • Economic cost with High watt density output.
  • Heating element

    Ferritic alloy powder metallurgical element , Mara FeCrAl, NiCr 80/20

  • Watt Density

    1/10 W/cm2

  • Max. Temperature

    Up to 1250°C

  • Cold resistance tolerance

    ≤3%

  • Power

    1 kW to 75 kW

Physical and Mechanical Properties of Ferritic alloys & Nicrome element

Heating Element Grade


 

Mara FeCrAl -Super

Mara FeCrAl-60

Mara FeCrAl-55

Mara FeCrAl-48

Mara Nichrome-80/20

Standard chemical composition  %

Al

6

6

5.5

4.8

Ni-80

Cr

23

23

23

23

20

Fe

Balance

Balance

Balance

Balance

0

Max continuous operating temperature

1420

1400

1300

1200

1200

Melting point

1500

1500

1500

1500

1400

Electric resistivity at 20℃

μΩ-m

1.45±5%

1.45±5%

1.40±5%

1.42±5%

1.08±5%

Density

g/cm3

7.1

7.1

7.2

7.2

8.4

Thermal expansion factor 20℃〜1,000℃

-1

14.8X10-6

13.6X10-6

13.6X10-6

14.8X10-6

17.6X10-6

Tensile strength 

N/mm2

650 〜900

650 〜900

650 〜900

630 〜850

700 〜900

Elongation

15 〜25

15 〜25

15 〜30

10 〜30

20 or more

Hardness 

Hv

220〜240

220〜240

220〜240

220〜240

150 〜190

Repeat bending frequency

F/R

≥5

≥5

≥5

≥5

 

Continuous service time

Hours/℃

≥300/1300

≥300/1300

≥300/1300

≥100/1300

≥300/1200

Magnetic properties

 

Magnetic

Magnetic

Magnetic

Magnetic

Non-Magnetic

 

Special Technique by Marathon for Radiant tube Heater

  • Marathon applied special Boron nitride coating on Radiant tube and Hangers to prevent impurities in the furnace atmosphere (especially aluminium /zinc holding & melting furnaces) for instance flux fumes, dust, oil, salt, sulphur, chlorine or carbon deposits can damage/puncture the radiant tube and heating element inside.
  • One of the most important design is using straight Element in place of U type element to protect element shorting at High Temperatures
  • Special Low weight high Temperature Ceramic (Special combination of High Purity Alumina and Cordrite) which gives High Strength at High Temperature and Low weight so stress on tube is less.
  • Special technique to join Terminal Rod and Center Rod with Additional Protective rods.

Bundle Rod Heater Accessories

Radiant Tube

Steanless steel SS grade, Incoloy, PMD, Cast alloys

Thickness of Tube

1.5 to 8mm

Length of Tube

300 to 5000mm (custmize diameter & length)

Hangers

Mara FeCrAl, NiCr  80/20 

Flange

MS, SS grade

Thermocouple Pocket

Alumina Tube(ceramic)

Control

Thermocouple, RTD’s, Thermostat

 

Application Areas

  • Primary aluminium holding and melting furnace
  • Galvanizing furnace in steel industries
  • Heat treatment furnace in automotive industries
  • Annealing furnace
  • Carburizing furnace