Robust Radiator (RR) and Sleeve Heater Heating Modules are provided in six categories:

Large KW Sleeve Heaters

All Robust-radiator modules are specified with the dimensions in the schematic below. Please read the power in the respective tables below.

Why are they long-lasting? MHI Robust Radiator is enclosed in a special RR Fractalin Ceramic, which displays extraordinarily low expansion or distortion. This is the secret of its longevity.
For A, B, C & D Dimensions, See Diagram Below. For Multi-Zone Models, RHUL type (1500C+), MRCL (1350C), GRR (1300C), and Stack (please scroll down)

Several Models are priced on the MHI Web Store

RR Dimensional

RR Dimensional

Please see the diagram above to specify the Robust Radiators
Please scroll below for various types, including Inline and Split Radiators

Heated Ultra and Magna-Coil inside a Radiator

Robust Radiator™ Applications.   To estimate approximate power requirement.  Click here.

The Robust Radiator uses,  include zone-heating, crucible-heating, pipe-heating or other applications requiring high temperatures and high versatility.

Suggested Uses
Multi-Zone Furnaces

Material Testing

Fluid heating

Tube Heating Crucible Melting
Annealing Crystal Growth

Wafer Productions

Semiconductor purge gas heating

Ink preheating systems •

Sintering and Food cooking equipment
Metal Melting. And Many More Uses

Hemo-dialysis fluid heating

The JOULE (J) is a commonly used unit of energy. The BTU is also an unit of energy. Another typical unit for energy is KWhr (Kilo-Watt-Hour).  See conversion tables.

RHUL Robust Radiator 1500°C-1700°C   

Crucible Crucible melter Stainless Shell Robust Radiator

Robust Radiators on the MHI Web-store

Linear Radiator on the Web Store

Standard Robust Radiator™ Configurations (High temperature – nominal range 1500C-1700C with end caps)

For A, B, C & D, Please Refer to the Dimensions in the Diagram 

Model # Maximum Power (Watts)* Heated Length (A) Overall Length (B) ID (C) OD (D)
RHUL-MP1125-6 825 4 in 6 in 1 in 5 in
RHUL-MP2125-6 1425 4 in 6 in 2 in 6 in
RHUL-MP3125-6 3000 4 in 6 in 3 in 6-7″ (inch), depending on the shell.
RHUL-MP4125-6 3200 4 in 6 in 4 in 6-8″ (inch), depending on the shell.

Sleeve Heater

Sleeve Heater

Sleeve Heater

Use for individual zone heaters in zone refining operations

Model # Max Power (Watts) Heated Length (A) Overall Length (B) ID (C) OD (D)
SLH1.5 350 0.25 in 2 in 1.5 in 5 in
SLH-3.0 800 0.25 in 2 in 3 in 6.5 in

GRR & Sleeve Models – High Uniformity Plug-in G-Robust Radiators (GRR) and Sleeves for 1250°C/1300°C user applications

High Uniformity G-Robust Radiators (GRR Models)  for 1250°C/1300°C
Multi-Zones Design

RR Robust Radiator plug in

RR Robust Radiator plugin

Provided with a Non-toxic Ceramic Enclosure, GRR High Uniformity Robust Radiators may be used to approximately 1300°C. For temperatures higher than 1300°C for the Robust Radiator, please click on Robust Radiators. Please call for Dimensions of GRR. Dimensions are for heated chamber size. Please add about 1″ – 2″ thickness for the ceramic shell. The following table provides dimensional guidance only for the heated zone. Use with DC or AC (50/60Hz).

GRR Model ID (in) L (in) Power (kW) (Nominal) Control Panel Volts**
GRR1(3)-110 1 3 1 IBPAN-110 115/120
GRR2(2)-120 2 2 1.4 IBPAN-110 120
GRR2(4)-220 2 4 2.5 IBPAN-220 220/230
GRR2(10)-220 2 10 6 IBPAN-220 220/230
GRR 3(3) -120 3 3 1.5 IBPAN-120 110/1200
GRR 3(5)-220 3 5 3 IBPAN-220 220/230
  • Click for GRR & Sleeve Models – High Uniformity Plug-in G-Robust Radiators (GRR) and Sleeves for 1250°C/1300°C user applications

** Plugin voltage indicates closest IBPAN preference. The GRR unit temperature, amperage (current), or power cannot be exceeded in any user configuration.   Configuration of use changes with end caps, load, control thermocouple flow placement, and insulation extent.   Please check the manual for maximum element temperature that cannot be exceeded.

Giant Sleeve BH_IMA Giant Sleeve Heaters >60KW – used for oil heaters and gas pipelines. Tilt provided As per MHI thermal code. Contact MHI for BH-IMA.
RR Dimensional

RR Dimensional

Inline Robust Radiator

Specifications (Inline is built to specification, minimum order may be required)

MHI’s Inline Robust Radiators™ are versatile, high-temperature heating devices capable of reaching temperatures up to 1700°C. They can be used in a variety of environments and positions. The MHI Inline Robust Radiator™ is available with optional end caps to achieve maximum chamber temperatures and an optional stainless steel shell that adds to the connection accessibility. You can order by part number or inquire about special needs. MHI will be happy to provide a personalized recommendation that will fit your needs.


  • Zone Furnaces
  • Ceramic Fiber Heater
  • Flue gas heater
  • Wafer Productions
  • Crystal Growth
  • Material Testing
  • Crucible Melting and more…
  • (Use with Airtorch™)
1 – 6 KW Power

BPAN-O-PLUS Control Panel

and UL model

Inline RR Model # Max. The temperature of the Heating Element (A) Heated Length (B) Overall Length (C) ID (D) OD
Magna- IMRCL-GA1125-4


MagnaCoil™ (Max. Temp. in RR ~1400°C) (~1 KW Power)

MagnaCoil™ (Max. Temp. in RR ~1400°C) (~1.5 KW Power)









Ultra-IRUHL-MP0625-4 UltraCoil™ (Max. Temp. in RR ~ 1700°C) (~1 KW Power) 2″ 4″ 0.5″ ~6.5″
Magna- IRHUL-MP1125-8 UlltaCoil™ (Max. Temp. RR ~1700°C) (~3.5  KW Power ) 6″ 8″ 1″ TBD
**Standard terminal length is about 1″ protrusions from the ceramic face. Aluminized for UltraCoil Model.

SS Models have Stainless Steel Shell Enclosures.

The temperature of the part may vary with thermal load; For IRHUL, the temperature rating is with end caps.

 See the illustration above for the dimensions and nomenclature of A, B, C, and D.

MRCL Robust Radiator 1300°C

Robust Radiators on the MHI Web Store

For A, B, C & D Please Refer to Dimensions in the Diagram 

Model # Maximum Power (Watts)* Heated Length (A) Overall Length (B) ID (C) OD (D)
(SS casing)

208-240V plug in

20 in 24 in 6 in >10 in
MRCL-GA1125-6 825 4 in 6in 1 in 5 in
MRCL-GA5125-6 Call 4 in 6 in 5 in 9 in
MRCL-GA2125-6 Call 4 in 6 in 2 in 6 in
MRCL-GA4125-6 Call 4 in 6 in 4 in 8 in
MRCL-GA3125-6 Call 4 in 6 in 3 in 7 in
(SS casing required)
12 kW

(High Power Models)

20 in 24 in 6in ~10 in

The MRCL-GA6125-24 is2a 220V/230V/240V plug in

Request Robust Radiator™ Quote

User Submitted Photographs

Robust Radiator™ as a Crucible Heater

Robust Radiator™ Heating Ceramic Tube (picture submitted in 2002, most likely still in use!)

Please review Testimonials


Some Of Our Many Satisified Customers Using the Robust Radiator

M.O., National Laboratory
“…the heating system that you helped me set up is working great!”

E.B., University
“…Robust Radiator is working perfect as a Crucible heater.”

L.C., Canada
“We just received the elements… they look great.”

Dave J, Washington
“I am very pleased with its performance. We feel it can be useful for a lot of our projects.”

Robust Radiator™ – R&D Project Use

More Testimonials…

Unlike fully finished furnaces, Robust Radiators™ are products that are typically components of a larger system. Please be fully conversant with the electrical and safety requirements during installation and use, including the use of connectors. Please call MHI at 513-772-0404 when in doubt. Contact MHI for custom solutions.

Split Radiator

Split Radiator – Split Radiators offer Lower Power.  MRCL class only.

Only as Special Order Custom Units. Total Watts 2 Halves- 200W (C= 1″ x A= 1″ ) (1100C)

Split Radiator with Shell is special make only e.g B=4″ and C=0.5″. Power~200W.

Split Compact Furnace

Model Number
Maximum Temperature
Request Quote

Compact Slider Furnace - Glove Box Furnace

Unlimited Power with Multiple Zones

  • High power density
  • Volume pricing
  • Non-toxic fiber-free enclosure
  • Match to your line voltage if required
  • Full line of electronic controls available
  • Rapid Delivery

Live Customer Support by phone (513-772-0404) or email. . Typical single and Multi-zone configurations are shown below. Terminal connectors are shown for each-zone.  End-caps and all other accessories available – see section on Robust Radiators.

Micro RR

Buy Now

GRR™ Micro Coil Robust Radiator

Robust radiator with Stainless Casing

Multi Zone Stacked GRR modules. 6 Stack Module.

(KiloJoule) = 0.9485 BTU=0.0002778 kWhr

The Watt (W) is a unit for power i.e. the energy used (or supplied) per unit time. 1 J/s (Joule per second) = 1 W (Watt)
Power-Units Conversion 1kW (KiloWatt) = 3414 BTU/hr

How much energy and what kind of power will be suitable for your heating application? The estimators in the link above may be used to calculate the energy required for common processes. Then by choosing a time over which the energy will be used one can calculate the best power required from the heater.