A guide for process engineers to select suitable cartridge heater type and design for their process heating

Hey there process engineers! Today, we're going to talk about something that's near and dear to your hearts: cartridge heaters. These little powerhouses are essential for many industrial processes, and choosing the right type and design can make all the difference in your operations. So let's dive in and create a guide that will help you make an informed decision.

Step 1: Determine the Heating Load

The first step in selecting a cartridge heater is to determine the heating load. This is the amount of heat required to maintain the desired temperature in your process. To calculate the heating load, you'll need to consider the following factors:

  • The volume of the heated space
  • The desired temperature rise
  • The thermal conductivity of the material being heated
  • The specific heat of the material being heated
  • Once you've determined the heating load, you'll have a better idea of the wattage and size of the cartridge heater you'll need.


Step 2: Choose the Right Heater Type

There are several types of cartridge heaters to choose from, including:

  • Straight: These are the most common type of cartridge heater and are ideal for cylindrical applications.
  • Dual diameter: These heaters have a larger diameter at one end, which can help distribute heat more evenly.
  • Swaged: These heaters have a tapered design that can help increase the surface area in contact with the heated material.
  • High density: These heaters have a higher wattage density, which can help provide more heat in a smaller space.

Consider the specific needs of your application when choosing a heater type.

Step 3: Determine the Sheath Material

The sheath material is the outer layer of the cartridge heater and is typically made of stainless steel or Incoloy. The sheath material should be chosen based on the following factors:

  • The temperature requirements of your application
  • The chemical compatibility of the sheath material with the heated material
  • The required mechanical strength of the heater

Stainless steel is a good all-around choice, but Incoloy may be a better option for high-temperature applications.

Step 4: Determine the Lead Wire Material

The lead wire material should be chosen based on the following factors:

  • The temperature requirements of your application
  • The required flexibility of the lead wire
  • The chemical compatibility of the lead wire material with the environment

Common lead wire materials include copper and stainless steel 

Step 5: Consider Cartridge Heater End Connections


Threaded Ends: Threaded cartridge heaters have male or female threads on one or both ends, allowing for easy installation and removal from the heating chamber. They are available in various thread sizes and styles, such as NPT (National Pipe Thread) and BSP (British Standard Pipe).

  1. Flange Ends: Flange cartridge heaters have a flange on one or both ends that allows for mounting onto a surface or inside a heating chamber. The flange provides a larger surface area for heat transfer and helps to distribute the heat evenly.
  2. Non-stick Ends: Non-stick cartridge heaters have a special coating on one or both ends that prevents the heater from sticking to the heating chamber. This feature is useful in applications where the heater may come into contact with materials that can cause sticking or fouling.
  3. Weld Ends: Weld cartridge heaters have a welded end that allows for secure attachment to a heating chamber or other components. This type of end connection is often used in high-temperature applications where a more robust connection is required.
  4. Brass Ends: Brass cartridge heaters have a brass end piece that provides a more durable and corrosion-resistant end than standard steel ends. Brass ends are often used in applications where the heater may come into contact with harsh chemicals or corrosive materials.
  5. Expansion Ends: Expansion cartridge heaters have a flexible end that allows for expansion and contraction due to temperature changes. This feature is useful in applications where the heater may be subjected to rapid temperature changes or vibration.

Step 6: Consider Special Features

There are several special features that can be added to cartridge heaters to improve their performance or durability, including:

  • Thermo-couples: These can be added to the heater to provide temperature feedback.
  • High-temperature insulation: This can help protect the lead wire and surrounding materials from high temperatures.
  • Stainless steel mesh: This can be added to the heater to increase its durability and resistance to vibration.

Consider the specific needs of your application when choosing special features.

Step 7: Consult with a Professional

When in doubt, consult with a professional. A knowledgeable supplier can help you choose the right cartridge heater for your application and provide valuable insights into the selection process.

By following these steps, you'll be well on your way to selecting a cartridge heater that meets the needs of your process and provides reliable, efficient heat for years to come. Happy engineering!

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