Insertion Heaters

insertion heaters

An insertion heater is an industrial heating element that is inserted into one or more drilled holes. This tube-shaped heater can be used to heat metal parts from the inside or heat a process liquid to a specific temperature.

These types of heaters range considerably in size, material and temperature range. The operating temperature can be very low and designed to keep a metal block warm, or it can be as high as 1,400 degrees Fahrenheit to quickly heat materials. There are many industries that use this style of heater, so the features and characteristics vary.

How Does an Insertion Heater Work?

The heating element of an insertion type heater is a resistance coil. This is wound around a ceramic core and surrounded by dielectric. The entire unit is encased in a metal sheath to protect against corrosion and damage to the resistance coil.

A major difference between insertion heaters, rod heaters and other industrial heaters is the cartridge design. Special- or general-purpose holes are drilled into a container or casing to allow the heater to be inserted. The hole can be larger if the temperature application is low, because this allows for easy installation and removal. For high-temperature applications, however, a tight fit is required.

Benefits of Cartridge Heaters

Cartridge heaters offer several significant benefits for various industrial applications. Depending on the location of your temperature application, a cartridge heater can offer the following benefits:

  • Versatile use: Heat water, air, metal and chemical solutions with this versatile heating element. Choose the optimal sheathing material to improve conductivity and avoid corrosion or other damage to the heating element.
  • Convenient heat application: Compared with other industrial heater designs, cartridge heaters offer convenient, consistent temperatures. Connect one or more units to a single controller and prepare for a high-temperature operation or maintain low, even temperatures.
  • Compact size: Cartridge heaters find their way into control panels, scientific equipment, closed circuits and many other applications thanks to their small size and powerful output.
  • Efficient heat transfer: Instead of heating an entire engine block or using additional transfer media, insertion type heaters provide directed heat to the specific point or medium required. In many cases, this makes it more efficient than other industrial heaters.

Cartridge Heater Applications

While the category of cartridge heaters offers excellent flexibility and efficient heat transfer, the particular unit you select can be custom-made to your application. Consider the applications of cartridge heaters before choosing a type and size that fits your specifications. Here are some common areas where an insertion type heater can efficiently power your process:

cartridge heaters
  • Die casting
  • Engine sump
  • Chemical solution
  • Food production
  • Control panel
  • 3D printing
  • Rubber molding
  • Closed circuit
  • Medical devices
  • Injection molding

Most situations where heat needs to be applied internally or to a specific point can benefit from a cartridge heater. Whether you’re heating a process liquid from a center point or providing specific heat to an oil reservoir, these heaters offer the dedicated temperature control you need.

Types of Cartridge Heaters

The most basic definition of a cartridge heater is an element that’s embedded in a housing. This heating element is then attached to, or inserted into, a material to be heated. Beyond that basic definition, these heaters can vary in type. Here are three common types heaters to consider:

  • Immersion
  • Square or round cartridge
  • Fin

Immersion Heaters

Immersion heaters are immersed in the material to be heated. This is usually a liquid, but can be another material. Instead of being submerged into an open barrel or reservoir, these heaters are inserted into the container.

A gasket prevents leakage, while a screw, flange or bolt connects the heating element to the wall of the container, engine block or other objects. Immersion heaters for water must have a watertight sheath that resists corrosion to heat efficiently in this environment. In some cases, the sheath must be made of food-safe or medical-grade materials.

Square or Round Cartridge Heaters

Most cartridge heaters have a tubular design. While not exactly the same as a tubular heater, these round cartridge heaters offer consistent heat around the entire surface. They don’t have any corners or hot spots.

A square cartridge heater can be used for specific applications. This shape may decrease the consistency of heat due to corners and other features, but it may be a suitable shape for your industrial process.

Fin Heaters

Fin heaters aren’t often thought of as cartridge heaters, because they aren’t inserted into a reservoir or other heating application. Instead, they heat an adjoining surface. This style of heater is still considered a type of cartridge heater.

The heating element is inserted into a fin housing, typically made of aluminum. The fins directly connect with the cartridge, creating efficient heat transfer. The fin heater is then adhered to a surface to provide the specified amount of heat.

Insertion Heater vs. Tubular Heater

While insertion and cartridge heaters can be used interchangeably, there are distinct differences between these terms and tubular heaters. Explore the differences to determine the optimal heating element for your application.

Insertion Type Heaters

This types of heater is a straight tube. It can be rectangular or cylindrical, but it doesn’t have any curves, bends or other shaping. The purpose of this straight heater is to provide consistent heat after being inserted into a hole drilled in a material.

Flexible electrical leads connect the heater to a power source and controller. These heaters range in size from 8 feet down to less than an inch in length. The sheathing used and the operating temperatures may vary, but insertion type heaters typically have this basic design.

Tubular Heaters

Tubular heaters, however, are typically shaped to provide more complex heating areas. Curves, bends and other geometric shapes allow these heaters to expand the heating area and create a more custom approach.

A tubular heater doesn’t necessarily need to be inserted into a hole. Many of these heaters are welded or otherwise installed directly to a surface. Some are even cast into metals. Ovens and other heating chambers often use this style of heating element.

How To Choose an Insertion Type Heater

Navigate the diverse options of these heaters by carefully reviewing your application and heating needs. If you’re expanding your heating process or looking to improve the efficiency of an existing process, use these features to choose an insertion style heater:

  • Gap
  • Watt density
  • Application

Cartridge Heater Gap

This type of heater needs to fit in the hole drilled into your reservoir or another component. If you already have a hole drilled, this narrows your search for the ideal heater. A temperature heater must fit with very little gap between the heater and the hole. Lower temperature operations can be more flexible in spacing.

Optimal Watt Density

The heat flow is measured in watts per square inch. This watt density describes how powerful or efficient your chosen heater is. A high watt density offers high temperatures but often comes with a shorter service life.

Your Application

Heating plastic for an injection molding process doesn’t have the same requirements as heating a vat of fry oil in a restaurant setting. Insertion type heaters need to be tailored to your specific application to achieve optimal results. Without industry- and application-specific features, your heater may not achieve your temperature or service life goals.