Crimped on Leads

• Crimped on leads are generally used where the temperature at the end of the heater exceeds the maximum rated temperature of the lead wire. Since the connection between the leads and power pins is made outside the heater, the unheated length at the lead end of the heater is kept to a minimum.

• Crimped on leads are not recommended for applications where the leads must be bent sharply near the heater, or in applications where the leads will be subject to a lot of flexing.

• The high temperature connectors are covered by 1-1/2” of 2500 volt silicone rubber coated fiberglass sleeving.

Right Angle Leads

Straight Braid

Right Angle Braid

Stainless Steel Flexible Conduit

Right Angle Stainless Steel Flexible Conduit

Convoluted Conduit

Right Angle Copper Elbow with Conduit

Copper Coupler

Ceramic Beads

Straight Pins

Sleeving

End Seals

End Seals and Lead Wires

FITTING OPTIONS

Single Ended NPT Fittings

Double Ended NPT Fittings

Custom Fittings

Straight Threads

OTHER OPTIONS

Internal Thermocouple

• Built-in thermocouples can be of type “J” or type “K”, grounded or ungrounded, and attached either at the disc end of middle of the cartridge.

• Thermocouple lead wire is 24 ga. solid and, unless
  otherwise specified, thermocouple leads are the same
  length as the power leads.

• When ordering, please specify type, location, grounded or ungrounded (if not specified, you will receive grounded), and insulation material (if not specified, you will receive fiberglass).

• Type “A”: Center of cores, measures heater temperature, not part temperature.

• Type “B”: Middle, grounded, also available as ungrounded.

• Type “C”: Disc end, ungrounded, also available as grounded.

Flanges

• Flanges can be welded on the lead end of the heater.

• Flanges can be used to hold a heater in place to
  prevent backing out during operation.

• Flanges also assist in heater removal.

• Flanges are 1/16” thick

Flanges

Mechanical Stops

• Weld Beads

• Tab Stops

• Custom Round Flanges

• Custom Rectangular Flanges

• Ideal for prventing heaters from sliding too far into the hole.

Length Control

• Due to the large reduction in diameter during the swaging process, cartridge heaters also grow in length. Although
  the length change is fairly predictable, it is influenced by many factors and yields a larger length tolerance than is
  found in other manufacturing techniques. When dealing with longer heaters this length variation can be an issue in
  some applications. There are several alternatives in these situations.

• The simplest is to just order the heater short enough that when at the maximum length tolerance it does not extend
  beyond the block it has been inserted into. The downside to this is that when the heater is at the short end of the
  length tolerance, you have empty space in the hole.

• An alternative is to have the heater trimmed to length after the swaging process. As only the unheated portion
  of the heater can be trimmed away, a large unheated section must be designed into the heater for trimming as
  illustrated below. The end result is the same amount of unheated block as you would have with the standard heater
  described above.

• Marathon does offer a heater called the HTS heater which allows for length adjustments in the heated area and
  produces an exact length heater with minimal unheated section. Unfortunately, this is only an option for some
  combinations of voltage, wattage, and heated length. Please consult with the engineering department at Marathon
  Heater to see if this is an option for your application.

• Another good option when watt densities and temperatures permit is a non-swaged heater. Non-swaged heaters are
  built with a standard length tolerance of ⅛”.

Flange Example

• When ordering a heater with 30” below the flange,
  the heater must be designed so that if they run on
  the short side of the tolerance. They are still long
  enough to have 30” below the flange (heater needs to
  be 30.06 long). This means that the heater has to be
  designed at 30.99” long and the heaters at the high
  side of the tolerance could be as long as 31.92” long.

No Flange Example

• When ordering a heater trimmed to exactly 30”, we can not trim
  away the heated portion of the heater, so we leave a cavity to trim
  and fill the remaining portion of the cavity with cement. We need
  to have at least 1/8” cavity to pot. So, we require a cavity length
  that, when we trim the longest heater, will leave us 1/8” of cavity.
  The heaters have to be designed so that the shortest heater is at
  least 30” long. That means they are designed at 30.92” and the
  longest one could be 31.98”.

Post Terminals

• Post terminals (also called screw terminals or stud terminals) are used in applications where easy lead replacement is desirable. They work great with ring terminals or fork terminals.

• Post terminals are only available for heaters 1/2” diameter and up.

• Terminals are #6-32 and supplied with 2 stainless steel washers and 2 stainless steel nuts on each stud.

Bent Cartridge Heater

• Cartridge heaters can be bent at any angle from 10°
  to 120°.

• Heaters must be bent in an unheated section.
  

• Can be constructed with most of the other options
  shown in this catalog.

End Tube Extensions

Spring Guard

• Spring guards are used for additional support in flexing applications.

Dual Voltage

• Dual Voltage cartridge heaters can be engineered to operate at different voltage ratings. To order, specify dual voltage and voltage requirements.

3 Phase

• Marathon Cartridge Heaters are available for three phase delta for high amperage applications. Certain restrictions apply.

Wattage

• We are sometimes asked about DC or frequencies other than 60 Hz. Neither of these affect the performance or wattage rating of the heater.

Individually Controlled Heat Zones

• Individually controlled heat zones give flexibility when needing to control the heat along the length of a cartridge heater. These zones are commonly used in sealing bar applications.

• Dual Zone are commonly constructed with 4 power leads.

• Three Zone heaters are constructed with (6) color coded leads. Yellow leads indicate disk end zone. Black leads indicate center zone. Red leads indicate lead end zone. Please consult factory for available diameters. Specify length and wattages of desired zones.

Distributed Wattage

• Distributed wattage heaters are often used in platens and sealing bars. Wattage is usually increased on the ends of the heater to compensate for end losses and maintain a constant temperature along the heated product.
  

• Specify desired lengths in inches and wattages in
  percentage.

Ready for any modification

• Marathon Heater, Inc. has thousands of standard stock cartridge heaters ready for a variety of modifications.
  

Stock heaters can ship the same day with the following options:

Diameters include:

• 1/4”
• 3/8”
• 1/2”
  
• 5/8”
• 3/4”

• All heaters come with either 14”, 26”, or 38” high temperature leads.

• Allow 1 extra day for options requiring potting.

• The Today Heaters part numbers are also easily available online at
  www.marathonheater.com.

• Orders must be received by 2:00 pm CST in order to ship the same day.

• Out of stock heaters and heaters with options such as fittings and potting will ship the next day.

How to Order:

• Step 1: Choose a Today Heater Stock
  part # that matches your
  required dimensions and
  wattage. Get the part #’s at
  marathonheater.com
  (xxxxxxxxx)

• Step 2: Choose your lead length (in).

• Step 3: Choose your option (Conduit,
  right angle leads, etc.).

• Step 4: Choose your lead protection
  length (in).

Options Chart:

Applications

• For applications where a swaged heater is not required, non-swaged cartridge heaters offer a cost effective alternative.

• Non-swaged heaters can be used up to 45 w/in² and to temperatures up to 800°F. Non-swaged heaters offer tighter length tolerances (±1/16”) than swaged heaters. Non-swaged heaters can be built with 3 independent heat zones. Nonswaged heaters are not recommended for applications where there is a lot of vibration or impact.

• Most of the lead configurations and options available for swaged HotRod heaters are also available for non-swaged cartridge heaters. Consult your Marathon Heater agent for more information.

• Standard leads are UL rated to 550°C. Leads are connected
  internally with nickel connectors.

• High temperature cement filling protects leads and internal
  parts. Epoxy and silicone rubber are also available.

• Nickel-Chromium resistance wire stretched evenly throughout
  the heated length.

• High purity MgO is vibratory filled into the heater for
  maximum heat transfer.

• 304 Stainless Steel sheath for superior oxidation resistance.

• Welded end disc to prevent contamination and moisture
  absorption.

Specifications

Clearance

• Clearance is determined by taking the hole diameter and subtracting the heater diameter.

• Cycling reduces heater life and high cycling applications should use lower numbers.

• Staying below these values will result in increased heater life.

Formula

• Watt density is calculated with the following formula:

Watt Density = (Wattage) / (Heated Length x Diameter x 3.14)

High Density Square Cartridge Heaters

• For those applications where a drilled hole is not practical, Marathon Heater offers square cartridge heaters. Unlike square cartridge heaters from other manufacturers, Marathon’s square cartridge heaters are swaged, allowing them to be used in high temperature and high watt density applications.

• Square heaters are ideal for milled slots in long platens where drilling a long hole would be too difficult. Square heaters are also much easier to remove from a slot after extended high temperature usage than removing a round heater from a drilled hole.

• Typical Applications:
  Bag Sealings
  Long Platens
  Cutting Jaws

• Available Diameters
  .375" Diameter
  .500"
  .625"
  
  
• Lead Options
  Right Angle Leads
  S/S braid
  S/S conduit
  Rt. Angle Braid
  Rt. Angle Conduit
  
  
• Heater Options
  Thermocouple
  Flanges
  Tab Stops
  Weld Beads
  Moisture Seals
  Distributive Wattage
  

Specifications

Recommended Maximum Watt Densities

Unheated Length at Lead End of Heater

Maximum HotRod Watt Density in 200°F Moving Air

Maximum HotRod Watt Density in Still Air.

HotRod Sheath Temperature in 70°F Still Air

Sheath Suitability Chart

• Our standard sheath material, 304 stainless steel, is suitable for most applications. For applications above 1200º F the use of Incoloy is recommended.

• The use of Incoloy below 1200º F will provide no performance improvement, however it will increase cost.
  
  
• For many immersion applications, especially tap water, 316 stainless steel is the best choice. Please see the chart below for help in determining the best sheath material for your application.

Ordering

• A correct and complete purchase order saves time and money for yourself and your customer. Here are some ordering
  tips to save playing phone tag with your customers. material for your application.
  
  
• Always distinguish overall length (OAL) and insertion length.
  

• Include flange and locating ring locations as measured from the disk end.

• Please provide a sketch for zone profiles or distributive wattage heaters.

• Don’t forget to indicate if an internal thermocouple is grounded or ungrounded and its location.

• Please remember to include quote numbers on all your purchase orders.

• Please reference applicable quote numbers on all orders.

Variation in Quantity

1. How long will my heater last?

• There is no standard heater life in the industry. The life of your heater is affected by:
  
  
  
• Application
• Application Temperature
• Watt Density
• Cycling
• Hole Fit
• Contamination

2. What is the maximum temperature for my heater?

• The sheath material will withstand temepratures of up to 1800 °F. See "Sheath Suitability Chart".

3. What is the maximum watt density allowed?

• Maximum watt density is determined by several factors including:
  
• Whether you are heating air, water, oil, metal. Etc.
• Application temperatures
• Hole Fit

4. How do you wire a 3 zone heater?

• The red wire is the lead end zone.
• The black wire is the center zone
• The yellow wire is the disk end zone

5. How much does a heater expand after energizing?

• Expansion is usually not a factor as the part being heated also expands.

6. How can I extend the life of my heater?

• The number one cause of heater failure is contamination.

• When foreign substances enter the heater and carbonize, this causes arcing and failure inside the heater. If temperature or other circumstances prevent you from using an end seal, avoid substances that could enter the heater at the lead entrance.

• Heat transfer compounds, especially grease based ones, are a common source of contamination.

• Wrapping tape around the lead wires is another common source of contamination as the adhesive melts and runs down into the heater. Remember, any organic or carbon based product has the potential to cause contamination.

• Excessive cycling is the next most common cause of failure. Avoid excessive cycling by properly sizing your heater and not using more wattage than necessary.

• Solid state controllers are also easier on the heaters than simple on-off controllers.