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:: Cartridge Heaters ::
MATRUSREE ELECTRO HEATS assists our customers with unique designs and solve existing problematic applications with special and custom engineered and manufactured thermal components which set our industry Standard for excellence. MATRUSREE cartridge heaters are round tubular heaters with electrical terminations on one side. These dependable heaters are made to withstand tough industrial usage. With a tolerance of +/- 0.002" on their outside diameter to secure a tight fit inside receptacle holes, and rock hard compaction of MgO insulation through swaging, these heaters can attain 1200 F sheath temperature.

MATRUSREE cartridges are available with various termination styles and mounting attachments. In cartridge heaters the resistance wire loops are positioned as close as possible to the outside shell. Because the MgO powder insulation around these loops is compacted by swaging and transformed into a very hard medium, heat transmission is very efficient. MATRUSREE cartridges can have up to 30-45 w/in2 watt densities. Cartridges are usually supplied with lead wires. The attachment of the leads to the central pins is done internally, in a 3/8" cold section. In excessively hot applications the length of this cold section could be increased. To facilitate installation and avoid excessive air pockets, cartridges are made 0.004" less than the nominal size of the receptacle hole with a tolerance of +/- 0.002".
  • Up to30-45 w/in2
  • Durable construction
  • Efficient heat transfer
  • Where space limitations apply.
  • Resistant to impact and vibration.
  • Dual voltage, selected diameters.
  • Three phase, selected diameters.
  • Distributed wattage.
  • Wide range of diameters.
  • Many termination styles.
  • U.L. approved and C.S.A. recognized.
  • Top quality ceramic element support.
  • Unique winding design allows faster heating and longer life.
  • High purity MgO packing for even heat distribution.
  • Fiberglass insulated lead wire is standard.
  • Various special features. Screw Plug- Brass Steel and Stainless Steel in 1", 1 1/4", 2" and 2 1/2" NPT sizes.
Features & Construction Details:
Cartridge Material:
  • The standard termination for Cartridge Heaters is internally connected flexible stranded nickel wire leads with high temperature fiberglass/Teflon tape insulation, UL approved for 300 Volt or 600 Volt service, rated at a continuous operating temperature of 482F (250C).
  • Helically wound Nickel-Chrome resistance wire.
  • Alloy 304 Stainless Steel is used to provide high temperature strength, good thermal conductivity and resistance to oxidation up to 1200F (650C). Alloy 304 is a Nickel-Chromium Stainless Steel.
  • Specially selected grain size high purity Magnesium Oxide (MgO) is used to fill all remaining space inside the ceramic insulator thus increasing thermal conductivity, dielectric strength and heater life
Available Dimensions:
Electrical Ratings:
Performance Ratings:
  • Maximum Temperature: 1200F (650C)
  • Maximum Watt Density: 30-45 W/in2 (4.6-7.0 W/cm2) depending on heater size and operating temperature.
Typical Application:
  • Heat Sealing Equipment
  • Laminating Equipment
  • Packaging Equipment
  • Molds and Dies
  • Food Processing
  • Refrigeration
  • Shoe Machinery
  • Glue Guns
  • Wax Pots
  • Heating Liquids
  • Heating Gases
  • Plastic molding
  • Heating tanks
  • Plastic extruders
  • Labeling machinery
Our Standard Cartridge heaters are designed as an economical, quality heater for lower temperature use (typically 40 watts per square inch, depending on the application). Standard Cartridges can meet U.L./C.S.A. approval. The Standard Cartridge Heater is made to withstand internal temperatures of up to1200 F (648 C) and features a stainless steel sheath for resistance to oxidation. High-purity magnesium oxide (MgO) fills any space around the resistor wire in order to optimize heat transfer and increase the life of the heater
  • Computer designed specifications.
  • 304 stainless steel sheath for oxidation resistance.
  • Ceramic insulator spaces helically wound resistor inside the sheath.
  • Helically wound nickel chromium resistor is of a conservative design for each application and evenly stretched through the ceramic insulators.
  • Fine grain high purity magnesium oxide (MgO) fills any voids around the resistor wire to optimize heat transfer, dielectric strength and life of the heater.
  • Resistor wire is joined to the leads by placing each end into nickel chromium which, upon crimping, affords a positive and consistent junction.
  • U.L. approved and C.S.A. certified flexible nickel conductor with fiberglass insulated lead wire 482 F, (250 C) is standard. Mica tape/fiberglass insulated 842 F, (450 C) available when requested as dictated by the application.
  • Disc end of the heater rests on a mica insulator and is held in position when the sheath is rolled over onto it. This is a standard assembly procedure unless the application requires moisture or waterproof sealing, at which time the end cap can be sealed by brazing or welding.
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.
  • 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.
Formula for Determination of Watt Density:
This lead termination provides flexibility because the lead wires are internally connected to the terminal pins. The lead wires can be sharply bent as they exit the ceramic insulating cap without exposing the bare wire or breaking the solid terminal pins.

  • Standard termination type for cartridge heaters.
  • Minimum 3?8" up to 1" cold section at the lead end is required.
  • Temperature at the lead end is not to exceed 482F (250C).
  • For higher temperature applications special lead wires can be used.
  • Built in thermocouples are available for all cartridge heater diameters
Straight Leads with Clip Support:


Right angle Leads With Clip Support:
Strain relief clip for leads subject to tension and stress. Clip support helps to minimize lead breakage where leads exit heater.
Silver Brazed Cable Sheath:
The armor cable is silver brazed directly to the cartridge heater, eliminating the coupling, to maintain an overall diameter equal to or smaller than the cartridge diameter.
Right Armor Cable:
Use this termination when space is limited and maximum protection is required. The armor cable is silver brazed to the cartridge sheath at 90. The sheath extension is potted with cement.
Important Installation Considerations:
  • For closest fit and best heat transfer, use reamed holes.
  • When possible, drill holes through the object being heated. This will make heater removal easier.
  • When using an anti-seize coating, do not apply over lead wires or any other current carrying conductors.
  • When using insulated tape or sleeving, check to make sure it is rated for the temperature of the application. Lower temperature rated materials can contain an adhesive or binder that can carbonize and become electrically conductive.
  • When using heaters near their maximum recommended watt density, it is recommended the temperature sensing probes be approximately 12.5 mm from the heater sheath.
  • Lead wires should not be located in the hole containing the cartridge heater during operation. This may cause the lead wires to be exposed to temperatures above their rated temperature.
  • When used in a vacuum application, make sure the lead end of the heater is outside the vacuum. If the lead has to be in the vacuum, consult MATRUSREE for specific recommendations.
  • Many applications will subject a heater's electrical terminations to one or more of the following potentially damaging conditions:
    • Moisture
    • Flexing
    • Oil and other
    • Abrasion contaminants
    • High temperature
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