Cartridge and Immersion Heaters

Cartridge, Immersion, Tubular, and Fin Heaters

• Round cartridge heaters
• Square cartridge heaters
• Cartridge immersion heaters
• Flanged cartridge heater
• Fin cartridge heater
• Insertion heater
• Rod heaters
• Pencil heaters
• Low density
• High density

Letters used for part numbers often don't relate directly to how the heaters components or their primary use. The naming convention is especially true when translated from one language to another. PSA, as an example, is used in many different industries and has different meanings in each.

Here are a few meanings of PSA in different industries:

• ·   Medical - Prostate-specific antigen
• ·   Business - Professional services automation
• ·   Finance - Public Securities Association
• ·   Legal - Pooling and servicing agreement
• ·   Public Service Announcement
• ·   Chemistry - Polar surface area
• ·   Professional squash association

For more PSA acronyms, check here.

Industrial sectors have even more variations, but for our purposes, PSA Heater in German refers to Patrone Silikon Alu, roughly translated to cartridge, silicone, aluminum. The ceramic heating element is inserted into a cartridge made of aluminum. The component is embedded in silicone to transfer or conduct the heat to the aluminum surface effectively. The aluminum surface passes the heat directly to a surface or material requiring the heat.

Less confusing ESH heater stands for Electric Surface Heater!

What is the difference between heaters, and when do you use each type of heater?

What are Cartridge Heaters?

Cartridge heater refers to the family of heaters. These heaters have the heating element embedded inside a housing that can be attached or inserted to transfer heat. The application and type of material or surface to be heated dictate the design.

Cartridge heaters are inserted through the wall of a container to heat the materials within. To warm the oil in an engine block or plastic in an extrusion line are examples. An extrusion line may use a heater in the die block itself to maintain the best operating temperature.

Other heating enclosures may come into contact with the liquid or material within the container, such as oil or corrosive materials, and require corrosive-resistant outer housing.

Some cartridge heaters screw in while others inserted into other heat conductive components. Square or rectangular-shaped heaters can fasten to the side of an object.

The common denominator is the heating element placed inside a container, often embedded in silicone rubber for heat transfer, wires terminated for the application is a cartridge heater.

When Would I Use a Tubular Heater?

Physics will explain that a tubular shape has a consistent surface area to radiate heat evenly across the surface. There are no hot spots on corners. These types are most likely to be inserted into a container or metal die to maintain temperature, as was mentioned in the cartridge heater explanation. Tubular or cartridge heaters have a very high watt density per square inch compared to other electric heaters. In all cases, the insulated lead wires bonded to one end of the cartridge for ease of use and protection against the heating element.

How are Immersion Heaters Used?

An immersion heater is another version of a cartridge heater named after its application. These heaters are inserted through a container wall into a liquid or other material or immersed in the material to be heated. The most common example is the heating elements that go into water heaters. These heaters referred to as cartridge & immersion heaters can be found in hundreds of different industrial applications. 

Heaters specifically designed to screw into place with a gasket to prevent leakage are cartridge heaters. Their outer coverings and screw or bolt fastener protect the heating elements against rust or corrosion. Unlike the typical water heater, an electric part exposed to the water in the tank, more sophisticated coverings could be high-grade stainless steel.

The stainless steel sheath and end connectors can be food or medical grade for additional protection against water, solvents, and steam.

Why are Fin Heaters Referred to as Cartridge Heaters?

A fin heater transfers heat to an adjoining surface rather than inserted into the container to be heated. To accomplish the necessary heat, transfer first a cartridge, square or tubular is inserted into the aluminum fin housing. The cartridge and fin housing have no insulating air between their surfaces.

The fin surfaces transfer heat to the air around it or the surface it is attached. Heat-conducting materials are used between surfaces to facilitate heat transfer. Heat-conducting tape supplied in some cases that adhere to the fin heater to the surface.

What is the Best Type of Heating Element?

PTC, Positive Temperature Coefficient ceramic heating elements are a superior choice for cartridge heaters. The application determines the choice. Medical devices or similar industrial equipment applications requiring precision heating PTC heaters are more common.

The ceramic PTC heating elements do not require electronic controls to precisely maintain heat, reducing the complexity and costs. Durability, reliability, and no maintenance requirements are advantages. High watt densities, low voltage, and energy-saving characteristics make them desirable for use with electronics.

Read the full blog on What is PTC and Why Use PTC Ceramic Heating Elements

Need more information or have a specific application in mind our engineers will help you find the right solution for your application.  DBK technical specification and CAD.