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Tubular Heaters
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Cartridge Heaters
Process Immersion Heaters
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   Tubular Heaters

MATRUSREE ELECTRO HEATS Designs and Manufactures Industrial Electric Tubular Heaters that set the industry Standard for excellence. The most versatile of all electric heating elements, the tubular heaters are capable of being formed into virtually any shape & configuration, brazed or welded to any metal surface, and can be cast into different metals.

Request For Quotation

Depending on the application different tube diameters and different tube Sheath materials are available. Heating of air requires an oxidized tube surface. The Commonly specified Sheath Materials are SS304, SS316, and SS316L & INCOLOY for high temperature applications. The range of ratings, sizes, materials and terminations available, makes the tubular heater adaptable to many industrial, commercial and Process applications. All wattages and voltages are possible as long as the resistance is within the fixed limits and the surface load will not be exceeded.

MATRUSREE uses only 95% pure MgO, the highest grade available for electric heating elements. Tubular Heaters can be Finned. see Finned tubular heaters.
Available in
See Heater Selection & Application
Features & Construction Details:

  • Tube Material Heating element in SS304 & other high temperature, corrosion resistant Alloys such as S316, SS316L, SS 321, Incoloy & InconelSheath Materials
  • Available Diameter 0.318" (8.1mm), 0.430" (11mm), 0.551" (14mm), 0.63" (16mm) element diameter with Tolerance of + 0.2mm. For Other Diameters Consult Matrusree
  • Available in Lengths upto 6.1 Meters (or) 20 Feet
  • Electrical Rating Several wattage and voltage combinations are available.
  • Temperature Limits 500 C.
  • Termination Standard M4 screw, M6 Adapter Termination & Lead Wire (for Special Applications)
  • End Seal RTV or Silicon Varnish
  • Watt Density Tube watt density of 30 w/in - suitable for many uses
  • Custom Shapes Custom configurations, Bends, lengths, watts, volts available.Tubular heaters can be
  • factory formed to practically any shape, sometimes to bends as small as one element tube diameter.
  • Terminal Enclosures Moisture resistant/explosion resistant terminal enclosure option.
  • Mounting Fittings Tubular Heating elements may be Bracket Mounted, clamped, Thread Nipple fitted, Flanged, casted into metals, Fitted with terminal box or spaced away from the work as radiant heaters. Elements can also be positioned in ducts or vessels for heating air or other gases.
  • Easy to install.
  • Excellent internal electrical insulation and heat conduction.
  • Electrically isolated sheath.
Typical Application:

There are numerous applications, mentioned above are a few..

  • In Plastic industries, domestic applications, high vacuum applications
  • Suitable for efficient baking.
  • Curing of plants enamels, lacquers and adhesives.
  • Tubular heaters are cast into aluminum for broad surface coverage and uniform heating application requirements
  • Please refer to general application guidelines, recommended watt densities, sheath temperature limitations, corrosion guide, and other engineering data to assist you with product selection.


The cutaway view of a typical MATRUSREE's tubular Heating element shows its basic construction. A coil of the highest-grade resistance Wire (80% nickel, 20% chromium) is precisely centered in a heavy gauge metal tube while the tube is filled with granular magnesium oxide powder. Terminal pins are Screwed / welded or silver soldered to the resistance coil at each end to provide an unheated length near the terminals and to secure the coil in the magnesium oxide. Through Swaging, the diameter of this assembly is reduced and the magnesium oxide compacted, insuring rapid heat transfer from the coil to the sheath, as well as high dielectric strength. After compaction, the element is processed in one of three Ways:

    1. Straight length elements are sealed and appropriate terminals applied.
    2. Formed elements are annealed and bent before they are Sealed and terminated.
    3. Finned elements are wound with a helical fin before they are sealed and terminated.
Picture Construction:
(Transform this Image into same Colour as all other Cutaway Cunstructiuon Images are Colour check the colour of other Cutaway Images)
Quality Control
From raw materials through the finished product, MATRUSREE maintains the highest standards in the industry through a series of Quality Control/Assurance checks.
  • Magnesium Oxide - MATRUSREE uses only 96% pure MgO, the highest grade available for electric heating elements. Each batch is checked against two Standards that determines tap density to assure a high insulation density. and for sieve analysis. Sieves to assure a high concentration of larger grains, which have better thermal conductivity and dielectric strength. As a result, MEH's elements have extremely high MgO density.

  • Recompaction - In the process of bending, hairline cracks can develop in the compacted magnesium oxide. These cracks, in turn, can lead to overheating and coil failure, especially at high temperatures or high watt densities. To prevent such failures, we recompress most bends with a center-to-center diameter of 2" or less, eliminating cracks in the magnesium oxide.

  • Alloy Wire- It is important to use the correct wire gauge to carry the Amperage required. A wire not large enough can overheat, become brittle and break. The ambient temperature must also be considered in choosing the correct type of wire and insulation. Make sure wiring to terminals is tight. Keep terminals away from heat if possible.

Finned Tubular Heaters
Finned tubular heating elements are of the type where the surface area is enlarged by a strip in order to heat gases. At high power the surface temperature is small and the heating element is short.

MATRUSREE's Finned Tubular Heaters are manufactured with the same rugged construction as the standard Tubular Heaters except a MILD STEEL ELECTROPLATED or a corrugated 304 STAINLESS STEEL FIN is helically wound on Heater Tube heater element. To insure a permanent bond & each end of the fin is fully brazed to the Heater sheath, for optimum heat dissipation and efficiency, as Brazed fins transfer heat at about double the efficiency of unbrazed designs. These heaters are ideal for heating air and select gases in forced and natural convection applications.
  • Possible Tube & Fin diameters:
    Heater OD: 8.2mm 11.2mm
    Fin OD: 28mm 30mm
  • Stainless Steel (Fin) sheath models are suitable for operating temperatures to 425 C.
  • Mild Steel (Fin) sheath (Electro plated) models are suitable for operating temperatures to 300 C.
  • Watt density: Max up to 35 w/in
  • High Temperature grade magnesium oxide insulation imbeds the resistance wire coil for optimum heat transfer & Dielectric Strength.
  • Mounting fitting available with Standard Bracket or Threaded Nipple arrangement.( Standard and custom options available)
  • Several wattage and voltage combinations are available.
Picture Construction:
(Transform this Image into same Colour as all other Cutaway Cunstructiuon Images are Colour check the colour of other Cutaway Images)
Typical Applications
  • Designed for rapid and uniform heat transfer for forced air heating.
  • Temperature boosting.
  • Channel air heaters for air conditioning and drying apparatus.
  • Industrial Ovens and Cabinets.
  • Duct Heater Assemblies.
  • Resistive Load Banks.
Additional Information Requires changes at some positions
Standard Sizes and Materials
The sheath materials available are stainless steel, steel, copper, and incoloy. Standard diameters are: .260", .315", .330", .375" and .450". Diameter tolerance is .010".
Sheath MaterialMax. Temp. Allowed on SheathMax. Length of SheathMax. Cold Lengths
St. Steel1200F324"96"
Sheath Materials and Watt Densities
ApplicationApprox.Operating Temp.Rec. Sheath MaterialWatts/ Of Element Surface
Clamped to SurfacesUp to 300F
Still Air (Sheath Temp.)800F
Clamped into Machined Grooves500F
St. Steel
Formula for Determination of Unit Wattage
Unit Wattage = Diameter x 3.142 x Heated Length x Allowable watts/
Electrical Tolerances and Limits
Sheath Diameter.260".315".375".440".490"
Max. OHMS/in.8050505050
Max. Voltage.250300480600600
Max. Amperes2030404040
Wattage tolerance is + 5%, -10% at rated volts.
Standard Length Tolerances
Sheath lengthLengthHeated Length
Up to 20" 1/16" 2%
20" to 100" 1/8" 2%
100" to 200" 1/4" 2%
Cold Ends
When not specified, cold ends will be the minimum length as shown in table below. Longer cold lengths up to 12" each end may be specified at no extra cost. Over 12", consult factory. Optional cold ends of unequal lengths are available.
Sheath lengthMinimum Cold Ends
Up to 20"1"
20" to 100"1 1/2"
100" to 200"4"
Mounting Fittings
Fittings are available with light jam nuts (plated steel), plain washers (plated steel), and/or copper gaskets.
Brass bushings are used with copper and steel sheaths.
Silver brazed stainless steel bushings are used with stainless steel and incoloy sheaths.
Welded stainless steel bushings are available at additional cost.
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Launched new Tublar heater for an Multi National Company, USA. For more details click here
Launched new Tublar heater for an Multi National Company, USA. For more details click here
Launched new Tublar heater for an Multi National Company, USA. For more details click here
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